373 results on '"Isabelle M"'
Search Results
2. Nonsteroidal ecdysone receptor agonists use a water channel for binding to the ecdysone receptor complex EcR/USP
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Dino Moras, Yoshiaki Nakagawa, Alastair G. McEwen, Isabelle M. L. Billas, Kotaro Mori, Christopher Browning, Taiyo Yokoi, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Centre de Biologie Intégrative (CBI), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Kyoto University, and univOAK, Archive ouverte
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0106 biological sciences ,Agonist ,ligand-binding domain ,Stereochemistry ,medicine.drug_class ,dibenzoylhydrazine ,Health, Toxicology and Mutagenesis ,Substituent ,ecdysone receptor ,010501 environmental sciences ,Ring (chemistry) ,01 natural sciences ,imidazole ,chemistry.chemical_compound ,structural adaptation ,[CHIM.CRIS]Chemical Sciences/Cristallography ,medicine ,Imidazole ,Molecule ,[CHIM.CRIS] Chemical Sciences/Cristallography ,0105 earth and related environmental sciences ,Hydrogen bond ,Regular Article ,water channel ,010602 entomology ,chemistry ,Nuclear receptor ,Insect Science ,Ecdysone receptor ,hormones, hormone substitutes, and hormone antagonists - Abstract
The ecdysone receptor (EcR) possesses the remarkable capacity to adapt structurally to different types of ligands. EcR binds ecdysteroids, including 20-hydroxyecdysone (20E), as well as nonsteroidal synthetic agonists such as insecticidal dibenzoylhydrazines (DBHs). Here, we report the crystal structures of the ligand-binding domains of Heliothis virescens EcR/USP bound to the DBH agonist BYI09181 and to the imidazole-type compound BYI08346. The region delineated by helices H7 and H10 opens up to tightly fit a phenyl ring of the ligands to an extent that depends on the bulkiness of ring substituent. In the structure of 20E-bound EcR, this part of the ligand-binding pocket (LBP) contains a channel filled by water molecules that form an intricate hydrogen bond network between 20E and LBP. The water channel present in the nuclear receptor bound to its natural hormone acts as a critical molecular adaptation spring used to accommodate synthetic agonists inside its binding cavity.
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- 2021
3. Cytoreductive surgery in the management of newly diagnosed glioblastoma in adults: a systematic review and evidence-based clinical practice guideline update
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Isabelle M. Germano, D. Ryan Ormond, Mairaj T. Sami, Joseph S. Domino, Timothy C. Ryken, and Jeffrey J. Olson
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Adult ,Cancer Research ,medicine.medical_specialty ,Evidence-based practice ,Neurology ,Newly diagnosed ,Neurosurgical Procedures ,Intraoperative MRI ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Biopsy ,medicine ,Humans ,medicine.diagnostic_test ,business.industry ,Disease Management ,Cytoreduction Surgical Procedures ,Guideline ,medicine.disease ,Oncology ,chemistry ,Evidence-Based Practice ,030220 oncology & carcinogenesis ,Practice Guidelines as Topic ,Neurology (clinical) ,Radiology ,Glioblastoma ,business ,Indocyanine green ,030217 neurology & neurosurgery - Abstract
These recommendations apply to adults with newly diagnosed or suspected glioblastoma. What is the effect of extent of surgical resection on patient outcome in the initial management of adult patients with suspected newly diagnosed glioblastoma? Level II: Maximal cytoreductive surgery is recommended in adult patients with suspected newly diagnosed supratentorial glioblastoma with gross total resection defined as removal of contrast enhancing tumor. Level III: Biopsy, subtotal resection, or gross total resection is suggested depending on medical comorbidities, functional status, and location of tumor if maximal resection may cause significant neurologic deficit. What is the role of cytoreductive surgery in adults with newly diagnosed bi-frontal “butterfly” glioblastoma? Level III: Resection of newly diagnosed bi-frontal “butterfly” glioblastoma is suggested to improve overall survival over biopsy alone. What is the goal of cytoreductive surgery in elderly adult patients with newly diagnosed glioblastoma? Level III: Elderly patients (> 65 years) show survival benefit with gross total resection and it is suggested they undergo cytoreductive surgery. What is the role of advanced intraoperative guidance techniques in cytoreductive surgery in adults with newly diagnosed glioblastoma? Level III: The use of intraoperative guidance adjuncts such as intraoperative MRI (iMRI) or 5-aminolevulinic acid (5-ALA) are suggested to maximize extent of resection in newly diagnosed glioblastoma. There is insufficient evidence to make a suggestion on the use of fluorescein, indocyanine green, or intraoperative ultrasound.
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- 2020
4. Biological Effects of Hydrocarbon Degradation Intermediates: Is the Total Petroleum Hydrocarbon Analytical Method Adequate for Risk Assessment?
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Isabelle M. Cozzarelli, Barbara A. Bekins, Donald E. Tillitt, Dalma Martinović-Weigelt, Jennifer C. Brennan, and Jennifer McGuire Illig
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chemistry.chemical_classification ,Biological Products ,Chromatography ,biology ,In vitro toxicology ,Fraction (chemistry) ,General Chemistry ,010501 environmental sciences ,Aryl hydrocarbon receptor ,Risk Assessment ,01 natural sciences ,Hydrocarbons ,chemistry.chemical_compound ,Petroleum ,Hydrocarbon ,Receptors, Aryl Hydrocarbon ,chemistry ,Dissolved organic carbon ,biology.protein ,Environmental Chemistry ,CALUX ,Total petroleum hydrocarbon ,Groundwater ,0105 earth and related environmental sciences ,Dichloromethane - Abstract
In crude oil contaminant plumes, the dissolved organic carbon (DOC) is mainly hydrocarbon degradation intermediates only partly quantified by the diesel range total petroleum hydrocarbon (TPHd) method. To understand potential biological effects of degradation intermediates, we tested three fractions of DOC: (1) solid-phase extract (HLB); (2) dichloromethane (DCM-total) extract used in TPHd; and (3) DCM extract with hydrocarbons isolated by silica gel cleanup (DCM-SGC). Bioactivity of extracts from five wells spanning a range of DOC was tested using an in vitro multiplex reporter system that evaluates modulation of the activity of 46 transcription factors; extracts were evaluated at concentrations equivalent to the well water samples. The aryl hydrocarbon receptor (AhR) and pregnane X receptor (PXR) transcription factors showed the greatest upregulation, with HLB exceeding DCM-total, and no upregulation in the hydrocarbon fraction (DCM-SGC). The HLB extracts were further studied with HepG2 chemically activated luciferase expression (CALUX) in vitro assays at nine concentrations ranging from 40 to 0.01 times the well water concentrations. Responses decreased with distance from the source but were still present at two wells without detectable hydrocarbons. Thus, our in vitro assay results indicate that risks associated with degradation intermediates of hydrocarbons in groundwater will be underestimated when protocols that remove these chemicals are employed.
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- 2020
5. Twin enzymes, divergent control: The cholesterogenic enzymes DHCR14 and LBR are differentially regulated transcriptionally and post-translationally
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Isabelle M. Capell-Hattam, Anika V. Prabhu, Andrew J. Brown, Lydia Qian, Gene Hart-Smith, and Laura J. Sharpe
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0301 basic medicine ,Oxidoreductases Acting on CH-CH Group Donors ,Ubiquitin-Protein Ligases ,Receptors, Cytoplasmic and Nuclear ,Constitutively active ,CHO Cells ,Protein degradation ,Reductase ,Biology ,Biochemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Cricetulus ,Gene expression ,Genetics ,Transcriptional regulation ,Animals ,Humans ,Receptor ,Molecular Biology ,chemistry.chemical_classification ,030102 biochemistry & molecular biology ,Protein Stability ,Cholesterol ,Cell Biology ,Lipids ,Sterol ,Cell biology ,030104 developmental biology ,Enzyme ,Gene Expression Regulation ,chemistry ,Organ Specificity ,lipids (amino acids, peptides, and proteins) ,Oxidoreductases ,Protein Processing, Post-Translational ,Biotechnology - Abstract
Cholesterol synthesis is a tightly regulated process, both transcriptionally and post-translationally. Transcriptional control of cholesterol synthesis is relatively well-understood. However, of the ∼20 enzymes in cholesterol biosynthesis, post-translational regulation has only been examined for a small number. Three of the four sterol reductases in cholesterol production, 7-dehydrocholesterol reductase (DHCR7), 14-dehydrocholesterol reductase (DHCR14), and lamin-B receptor (LBR), share evolutionary ties with a high level of sequence homology and predicted structural homology. DHCR14 and LBR uniquely share the same Δ-14 reductase activity in cholesterol biosynthesis, yet little is known about their post-translational regulation. We have previously identified specific modes of post-translational control of DHCR7, but it is unknown whether these regulatory mechanisms are shared by DHCR14 and LBR. Using CHO-7 cells stably expressing epitope-tagged DHCR14 or LBR, we investigated the post-translational regulation of these enzymes. We found that DHCR14 and LBR undergo differential post-translational regulation, with DHCR14 being rapidly turned over, triggered by cholesterol and other sterol intermediates, whereas LBR remained stable. DHCR14 is degraded via the ubiquitin-proteasome system, and we identified several DHCR14 and DHCR7 putative interaction partners, including a number of E3 ligases that modulate DHCR14 levels. Interestingly, we found that gene expression across an array of human tissues showed a negative relationship between the C14-sterol reductases; one enzyme or the other tends to be predominantly expressed in each tissue. Overall, our findings indicate that whereas LBR tends to be the constitutively active C14-sterol reductase, DHCR14 levels are tunable, responding to the local cellular demands for cholesterol.
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- 2020
6. Shale gas development has limited effects on stream biology and geochemistry in a gradient-based, multiparameter study in Pennsylvania
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Jason Ditty, Josh Lookenbill, Adam C. Mumford, Luke Ulsamer, Kelly O. Maloney, Isabelle M. Cozzarelli, Sarah Nettemann, Arianne Proctor, and Denise M. Akob
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Watershed ,macroinvertebrates ,STREAMS ,Biology ,hydraulic fracturing ,water quality ,Rivers ,Animals ,Ecosystem ,Oil and Gas Fields ,Hydrology ,Multidisciplinary ,Bacteria ,Chemistry ,microbiology ,Biota ,Biological Sciences ,Pennsylvania ,Invertebrates ,Current (stream) ,Benthic zone ,Physical Sciences ,Marcellus Shale ,Water quality ,Oil shale ,Environmental Sciences ,Environmental Monitoring - Abstract
Significance This investigation provides a comprehensive evaluation of the geochemical and biological effects of shale gas development on 25 small watersheds over the course of 2 y. Sampling headwater streams seasonally over two consecutive years yielded no statistically significant relationships between the intensity, presence, or absence of shale gas development and any signal in a comprehensive set of chemical constituents (including those recognized as oil and gas geochemical tracers) or any changes in microbial or benthic macroinvertebrate community composition. This work provides a framework for investigations of anthropogenic effects stemming from natural resource development, and highlights the importance of conducting studies which control for regional and temporal variability., The number of horizontally drilled shale oil and gas wells in the United States has increased from nearly 28,000 in 2007 to nearly 127,000 in 2017, and research has suggested the potential for the development of shale resources to affect nearby stream ecosystems. However, the ability to generalize current studies is limited by the small geographic scope as well as limited breadth and integration of measured chemical and biological indicators parameters. This study tested the hypothesis that a quantifiable, significant relationship exists between the density of oil and gas (OG) development, increasing stream water concentrations of known geochemical tracers of OG extraction, and the composition of benthic macroinvertebrate and microbial communities. Twenty-five headwater streams that drain lands across a gradient of shale gas development intensity were sampled. Our strategy included comprehensive measurements across multiple seasons of sampling to account for temporal variability of geochemical parameters, including known shale OG geochemical tracers, and microbial and benthic macroinvertebrate communities. No significant relationships were found between the intensity of OG development, shale OG geochemical tracers, or benthic macroinvertebrate or microbial community composition, whereas significant seasonal differences in stream chemistry were observed. These results highlight the importance of considering spatial and temporal variability in stream chemistry and biota and not only the presence of anthropogenic activities in a watershed. This comprehensive, integrated study of geochemical and biological variability of headwater streams in watersheds undergoing OG development provides a robust framework for examining the effects of energy development at a regional scale.
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- 2020
7. The cholesterol synthesis enzyme lanosterol 14α-demethylase is post-translationally regulated by the E3 ubiquitin ligase MARCH6
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Samuel J. Gullo, Nicola A. Scott, Winnie Luu, Andrew J. Brown, Isabelle M. Capell-Hattam, and Laura J. Sharpe
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Cell Homeostasis & Autophagy ,Oxidoreductases Acting on CH-CH Group Donors ,cytochrome P450 ,Ubiquitin-Protein Ligases ,DHCR24 ,Nerve Tissue Proteins ,MARCH6 ,CHO Cells ,Reductase ,Biochemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Sterol 14-Demethylase ,0302 clinical medicine ,Cricetulus ,Animals ,Humans ,Molecular Biology ,Intramolecular Transferases ,Research Articles ,030304 developmental biology ,0303 health sciences ,biology ,Lanosterol ,protein turnover ,Lipogenesis ,Cytochrome P450 ,cholesterol ,Membrane Proteins ,Cell Biology ,Sterol ,Ubiquitin ligase ,Metabolic pathway ,lanosterol 14α-demethylase ,Metabolism ,chemistry ,Proteolysis ,biology.protein ,Demethylase ,lipids (amino acids, peptides, and proteins) ,Protein Processing, Post-Translational ,030217 neurology & neurosurgery ,Lanosterol synthase ,HeLa Cells - Abstract
Cholesterol synthesis is a tightly controlled pathway, with over 20 enzymes involved. Each of these enzymes can be distinctly regulated, helping to fine-tune the production of cholesterol and its functional intermediates. Several enzymes are degraded in response to increased sterol levels, whilst others remain stable. We hypothesised that an enzyme at a key branch point in the pathway, lanosterol 14α-demethylase (LDM) may be post-translationally regulated. Here, we show that the preceding enzyme, lanosterol synthase is stable, whilst LDM is rapidly degraded. Surprisingly, this degradation is not triggered by sterols. However, the E3 ubiquitin ligase membrane-associated ring-CH-type finger 6 (MARCH6), known to control earlier rate-limiting steps in cholesterol synthesis, also control levels of LDM and the terminal cholesterol synthesis enzyme, 24-dehydrocholesterol reductase. Our work highlights MARCH6 as the first example of an E3 ubiquitin ligase that targets multiple steps in a biochemical pathway and indicates new facets in the control of cholesterol synthesis.
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- 2020
8. Oil and Gas Wastewater Components Alter Streambed Microbial Community Structure and Function
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Andrea Fraser, Cassandra Rashan Harris, William H. Orem, Matthew S. Varonka, Denise M. Akob, Isabelle M. Cozzarelli, and Adam C. Mumford
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Microbiology (medical) ,Sediment ,microbial communities ,Anoxic waters ,microbial activity ,Microbiology ,QR1-502 ,chemistry.chemical_compound ,class II injection well ,Hydraulic fracturing ,Wastewater ,Microbial population biology ,chemistry ,Environmental chemistry ,Environmental science ,DBNPA ,unconventional oil and gas production ,Microcosm ,Groundwater ,Original Research ,wastewaters - Abstract
The widespread application of directional drilling and hydraulic fracturing technologies expanded oil and gas (OG) development to previously inaccessible resources. A single OG well can generate millions of liters of wastewater, which is a mixture of brine produced from the fractured formations and injected hydraulic fracturing fluids (HFFs). With thousands of wells completed each year, safe management of OG wastewaters has become a major challenge to the industry and regulators. OG wastewaters are commonly disposed of by underground injection, and previous research showed that surface activities at an Underground Injection Control (UIC) facility in West Virginia affected stream biogeochemistry and sediment microbial communities immediately downstream from the facility. Because microbially driven processes can control the fate and transport of organic and inorganic components of OG wastewater, we designed a series of aerobic microcosm experiments to assess the influence of high total dissolved solids (TDS) and two common HFF additives—the biocide 2,2-dibromo-3-nitrilopropionamide (DBNPA) and ethylene glycol (an anti-scaling additive)—on microbial community structure and function. Microcosms were constructed with sediment collected upstream (background) or downstream (impacted) from the UIC facility in West Virginia. Exposure to elevated TDS resulted in a significant decrease in aerobic respiration, and microbial community analysis following incubation indicated that elevated TDS could be linked to the majority of change in community structure. Over the course of the incubation, the sediment layer in the microcosms became anoxic, and addition of DBNPA was observed to inhibit iron reduction. In general, disruptions to microbial community structure and function were more pronounced in upstream and background sediment microcosms than in impacted sediment microcosms. These results suggest that the microbial community in impacted sediments had adapted following exposure to OG wastewater releases from the site. Our findings demonstrate the potential for releases from an OG wastewater disposal facility to alter microbial communities and biogeochemical processes. We anticipate that these studies will aid in the development of useful models for the potential impact of UIC disposal facilities on adjoining surface water and shallow groundwater.
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- 2021
9. Involvement of circulating factors in the transmission of paternal experiences through the germline
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Eric A. Miska, Pierre-Luc Germain, Niharika Gaur, Katharina Gapp, Isabelle M. Mansuy, Anastasiia Efimova, Ali Jawaid, Deepak K. Tanwar, Nicola Zamboni, Gretchen van Steenwyk, Francesca Manuella, Kristina M. Thumfart, University of Zurich, and Mansuy, Isabelle M
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medicine.medical_specialty ,Offspring ,paternal experiences ,blood serum ,PPAR ,sperm ,transmission ,Peroxisome proliferator-activated receptor ,610 Medicine & health ,Genetics and Molecular Biology ,Biology ,Chromatin, Epigenetics, Genomics & Functional Genomics ,General Biochemistry, Genetics and Molecular Biology ,Germline ,PPAR agonist ,Article ,Transcriptome ,03 medical and health sciences ,0302 clinical medicine ,Blood serum ,1300 General Biochemistry, Genetics and Molecular Biology ,Internal medicine ,2400 General Immunology and Microbiology ,medicine ,1312 Molecular Biology ,Molecular Biology ,030304 developmental biology ,chemistry.chemical_classification ,0303 health sciences ,10242 Brain Research Institute ,General Immunology and Microbiology ,General Neuroscience ,2800 General Neuroscience ,Articles ,Paternal Exposure ,Endocrinology ,Metabolism ,Nuclear receptor ,chemistry ,General Biochemistry ,570 Life sciences ,biology ,030217 neurology & neurosurgery ,Neuroscience - Abstract
Environmental factors can change phenotypes in exposed individuals and offspring and involve the germline, likely via biological signals in the periphery that communicate with germ cells. Here, using a mouse model of paternal exposure to traumatic stress, we identify circulating factors involving peroxisome proliferator‐activated receptor (PPAR) pathways in the effects of exposure to the germline. We show that exposure alters metabolic functions and pathways, particularly lipid‐derived metabolites, in exposed fathers and their offspring. We collected data in a human cohort exposed to childhood trauma and observed similar metabolic alterations in circulation, suggesting conserved effects. Chronic injection of serum from trauma‐exposed males into controls recapitulates metabolic phenotypes in the offspring. We identify lipid‐activated nuclear receptors PPARs as potential mediators of the effects from father to offspring. Pharmacological PPAR activation in vivo reproduces metabolic dysfunctions in the offspring and grand‐offspring of injected males and affects the sperm transcriptome in fathers and sons. In germ‐like cells in vitro, both serum and PPAR agonist induce PPAR activation. Together, these results highlight the role of circulating factors as potential communication vectors between the periphery and the germline., The EMBO Journal, 39 (23), ISSN:0261-4189, ISSN:1460-2075
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- 2020
10. Water
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G.-H. Crystal Ng, Isabelle M. Cozzarelli, Madeline E. Schreiber, Aubrey J. Dunshee, Brady A. Ziegler, and Geosciences
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Geography, Planning and Development ,0207 environmental engineering ,chemistry.chemical_element ,iron reduction ,Aquifer ,02 engineering and technology ,010501 environmental sciences ,Aquatic Science ,oil ,01 natural sciences ,Biochemistry ,biodegradation ,chemistry.chemical_compound ,Dissolved organic carbon ,020701 environmental engineering ,TD201-500 ,Arsenic ,0105 earth and related environmental sciences ,Water Science and Technology ,geography ,geography.geographical_feature_category ,sorption ,Water supply for domestic and industrial purposes ,arsenic ,reactive transport modeling ,Hydraulic engineering ,Anoxic waters ,surface complexation ,Plume ,chemistry ,Environmental chemistry ,Petroleum ,Environmental science ,Water quality ,TC1-978 ,Groundwater - Abstract
We used a reactive transport model to investigate the cycling of geogenic arsenic (As) in a petroleum-contaminated aquifer. We simulated As mobilization and sequestration using surface complexation reactions with Fe(OH)3 during petroleum biodegradation coupled with Fe-reduction. Model results predict that dissolved As in the plume will exceed the U.S. and EU 10 µg/L drinking water standard for ~400 years. Non-volatile dissolved organic carbon (NVDOC) in the model promotes As mobilization by exerting oxygen demand, which maintains anoxic conditions in the aquifer. After NVDOC degrades, As re-associates with Fe(OH)3 as oxygenated conditions are re-established. Over the 400-year simulation, As transport resembles a “roll front” in which: (1) arsenic sorbed to Fe(OH)3 is released during Fe-reduction coupled to petroleum biodegradation, (2) dissolved As resorbs to Fe(OH)3 at the plume’s leading edge, and (3) over time, the plume expands, and resorbed As is re-released into groundwater. This “roll front” behavior underscores the transience of sorption as an As attenuation mechanism. Over the plume’s lifespan, simulations suggest that As will contaminate more groundwater than benzene from the oil spill. At its maximum, the model simulates that ~5.7× more groundwater will be contaminated by As than benzene, suggesting that As could pose a greater long-term water quality threat than benzene in this petroleum-contaminated aquifer.
- Published
- 2021
11. Nitrate, ammonium, and phosphorus drive seasonal nutrient limitation of chlorophytes, cyanobacteria, and diatoms in a hyper‐eutrophic reservoir
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Tanner J. Williamson, Michael J. Vanni, María J. González, and Isabelle M. Andersen
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Cyanobacteria ,biology ,Phosphorus ,chemistry.chemical_element ,Aquatic Science ,Oceanography ,biology.organism_classification ,chemistry.chemical_compound ,Nutrient ,chemistry ,Nitrate ,Environmental chemistry ,Environmental science ,Ammonium ,Eutrophication - Published
- 2019
12. The effect of extracellular matrix protein binding and culture confluence status on the effect of ROCK on TNF-α- and IL-1-stimulated CXCL8 secretion by colonic epithelial cell
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Sayantan Banerjee, Isabelle M Weishaar, and Dennis W. McGee
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Collagen Type IV ,musculoskeletal diseases ,0301 basic medicine ,Colon ,Pyridines ,Cell Culture Techniques ,Cell Count ,Collagen Type I ,Extracellular matrix ,03 medical and health sciences ,0302 clinical medicine ,Humans ,Secretion ,Interleukin 8 ,Extracellular Matrix Proteins ,rho-Associated Kinases ,Confluency ,biology ,Tumor Necrosis Factor-alpha ,Chemistry ,Interleukin-8 ,Epithelial Cells ,Cell Biology ,General Medicine ,Amides ,Fibronectins ,Cell biology ,Fibronectin ,030104 developmental biology ,Cell culture ,030220 oncology & carcinogenesis ,biology.protein ,Laminin ,Caco-2 Cells ,Extracellular matrix protein binding ,Stem cell ,Interleukin-1 ,Developmental Biology - Abstract
Colonic and intestinal epithelial cells (EC) attach to a basement membrane of laminins, fibronectin, and collagen IV. Wounding of the epithelial layer can change the types of extracellular matrix (ECM) proteins to which the EC attach. In this study, we determined the effect of culturing Caco-2 cells on different ECM proteins on the capacity of EC to produce TNF-α- or IL-1-stimulated CXCL8. The effect of the ECM proteins was such that CXCL8 secretion by cells cultured on collagen I > collagen IV > fibronectin or laminin-111. However, suppression of ROCK activity resulted in a similar 75 to 85% suppression of CXCL8 secretion regardless of the ECM protein type. This suggests that EC can produce different levels of CXCL8 depending on the type of ECM proteins they attach to, but all cases result in a similar requirement for ROCK activity for optimal CXCL8 secretion. Furthermore, when confluent cells were compared to subconfluent cells, the level of TNF- or IL-1-stimulated CXCL8 secretion was greatly elevated with the subconfluent cells and inhibiting ROCK had no effect on CXCL8 secretion levels by the confluent cells. These experiments suggest that CXCL8 responses by confluent cells, which would model for intact, unwounded epithelial, do not involve ROCK activation. However, CXCL8 responses by subconfluent cells, which would model for cells attaching to and moving on ECM proteins in wounded epithelia, require ROCK activation for greatly elevated CXCL8 responses. These results provide a model to examine the important conditions which regulate chemokine production by EC in wounded epithelia.
- Published
- 2019
13. Associations between environmental pollutants and larval amphibians in wetlands contaminated by energy-related brines are potentially mediated by feeding traits
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R. Ken Honeycutt, Kelly L. Smalling, Todd M. Preston, Blake R. Hossack, Isabelle M. Cozzarelli, and Chauncey W. Anderson
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Pollution ,Geologic Sediments ,010504 meteorology & atmospheric sciences ,Health, Toxicology and Mutagenesis ,media_common.quotation_subject ,chemistry.chemical_element ,Wetland ,Wastewater ,010501 environmental sciences ,Toxicology ,Ambystoma ,01 natural sciences ,Chloride ,medicine ,Animals ,0105 earth and related environmental sciences ,media_common ,Pollutant ,geography ,geography.geographical_feature_category ,General Medicine ,Contamination ,Mercury (element) ,chemistry ,Metals ,Larva ,Wetlands ,Environmental chemistry ,North America ,Environmental science ,Salts ,Metalloid ,Anura ,Water Pollutants, Chemical ,Environmental Monitoring ,medicine.drug - Abstract
Energy production in the Williston Basin, located in the Prairie Pothole Region of central North America, has increased rapidly over the last several decades. Advances in recycling and disposal practices of saline wastewaters (brines) co-produced during energy production have reduced ecological risks, but spills still occur often and legacy practices of releasing brines into the environment caused persistent salinization in many areas. Aside from sodium and chloride, these brines contain elevated concentrations of metals and metalloids (lead, selenium, strontium, antimony and vanadium), ammonium, volatile organic compounds, hydrocarbons, and radionuclides. Amphibians are especially sensitive to chloride and some metals, increasing potential effects in wetlands contaminated by brines. We collected bed sediment and larval amphibians (Ambystoma mavortium, Lithobates pipiens and Pseudacris maculata) from wetlands in Montana and North Dakota representing a range of brine contamination history and severity to determine if contamination was associated with metal concentrations in sediments and if metal accumulation in tissues varied by species. In wetland sediments, brine contamination was positively associated with the concentrations of sodium and strontium, both known to occur in oil and gas wastewater, but negatively correlated with mercury. In amphibian tissues, selenium and vanadium were associated with brine contamination. Metal tissue concentrations were higher in tadpoles that graze compared to predatory salamanders; this suggests frequent contact with the sediments could lead to greater ingestion of metal-laden materials. Although many of these metals may not be directly linked with energy development, the potential additive or synergistic effects of exposure along with elevated chloride from brines could have important consequences for aquatic organisms. To effectively manage amphibian populations in wetlands contaminated by saline wastewaters we need a better understanding of how life history traits, species-specific susceptibilities and the physical-chemical properties of metals co-occurring in wetland sediments interact with other stressors like chloride and wetland drying.
- Published
- 2019
14. The Effect of IL-26 on TNF-α-Induced CXCL8 Responses by Colonic Epithelial Cell Lines
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Dennis W. McGee, Brody M. Wiles, Isabelle M Weishaar, and Rebecca S. Young
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0301 basic medicine ,Chemokine ,Colon ,MAP Kinase Signaling System ,medicine.medical_treatment ,Immunology ,p38 Mitogen-Activated Protein Kinases ,03 medical and health sciences ,0302 clinical medicine ,NF-KappaB Inhibitor alpha ,Cell Line, Tumor ,medicine ,Humans ,Secretion ,Interleukin 8 ,Phosphorylation ,Receptor ,Cells, Cultured ,biology ,Tumor Necrosis Factor-alpha ,Chemistry ,Interleukins ,Interleukin-8 ,Interleukin ,Epithelial Cells ,General Medicine ,IκBα ,030104 developmental biology ,Cytokine ,030220 oncology & carcinogenesis ,biology.protein ,Cancer research ,Tumor necrosis factor alpha ,HT29 Cells ,Interleukin-1 - Abstract
Th17 cells of the intestine and colon can produce several important cytokines during mucosal inflammation. However, few studies have focused on the role of IL-26 in intestinal inflammations. Colonic epithelial cells express receptors for IL-26, and this cytokine has been shown to induce the HT-29 colonic epithelial cell line to produce the chemokine CXCL8. However, epithelial cells would function in a cytokine network environment during mucosal inflammation and any effect of IL-26 on colonic epithelial cell chemokine responses could be affected by the presence of other potent pro-inflammatory cytokines like TNF-α and IL-1. Therefore, we investigated the effect of IL-26 with TNF-α or IL-1 on colonic epithelial cell line secretion of CXCL8. IL-26 alone had no effect on HT-29 or DLD1 cell line CXCL8 secretion. Yet, IL-26 was found to significantly enhance TNF-α-induced, but not IL-1-induced, CXCL8 secretion, but only at high levels of TNF-α. Similar results were seen with DLD1 cells. IL-26 did not enhance TNF-α-induced CXCL8 mRNA levels and did not affect TNF-α-induced IκBα phosphorylation or degradation. However, signaling through ERK and p38 MAPK were determined to be involved in the enhancing effect of IL-26 on the TNF-α-induced CXCL8 secretion, perhaps through known post-translational effects. These results suggest that the role of IL-26 in intestinal inflammation may be limited to enhancing CXCL8 secretion in the presence high levels of TNF-α, such as may occur in inflammatory bowel disease. Abbreviations: DMEM, Dulbecco's Modified Eagle's Medium; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; IBD, inflammatory bowel disease; IL, interleukin; ITS, insulin, transferrin, selenium; TBS, Tris buffered saline; TNF, tumor necrosis factor.
- Published
- 2019
15. Biological Effects of Elevated Major Ions in Surface Water Contaminated by a Produced Water from Oil Production
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Jeffery A. Steevens, Danielle Cleveland, Isabelle M. Cozzarelli, Ning Wang, and James L. Kunz
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Unionidae ,Lampsilis siliquoidea ,010504 meteorology & atmospheric sciences ,Health, Toxicology and Mutagenesis ,Cyprinidae ,Wastewater ,010501 environmental sciences ,Toxicology ,01 natural sciences ,Rivers ,biology.animal ,Toxicity Tests ,Animals ,Ecotoxicology ,Oil and Gas Fields ,0105 earth and related environmental sciences ,Ions ,biology ,Chemistry ,General Medicine ,Mussel ,Minnow ,biology.organism_classification ,Pollution ,Produced water ,Environmental chemistry ,Pimephales promelas ,Surface water ,Water Pollutants, Chemical - Abstract
Produced water (PW) from oil and gas extraction processes has been shown to contain elevated concentrations of major ions. The objective of this study was to determine the potential effects of elevated major ions in PW-contaminated surface water on a fish (fathead minnow, Pimephales promelas) and a unionid mussel (fatmucket, Lampsilis siliquoidea) in short-term (7-day) exposures. The test organisms were exposed in 3 reconstituted waters formulated with 1, 2, and 4 times the major ions measured at a PW-contaminated stream site 1 month after a PW spill from an oil production wastewater pipeline in the Williston Basin, North Dakota. A reconstituted water mimicking the ionic composition of an upstream site from the spill was used as a reference water. Significant reductions in survival and growth of the fish were observed in the 4× treatment compared with the reference. The mussels were more sensitive than the fish, with significant reductions in survival in the 2× and 4× treatments, and significant reductions in length in the 1× and 2× treatments. Overall, these results indicate that elevated concentrations of major ions in PW-contaminated surface waters could adversely affect the fish and mussels tested and potentially other aquatic organisms.
- Published
- 2019
16. Assessing structure/property relationships and synthetic protocols in the fabrication of poly(oxanorbornene imide) single-chain nanoparticles
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Justin P. Cole, Sawyer D. Cawthern, Riya Saxena, Sarah J. Benware, Jacob J. Lessard, Ruiwen Chen, Erik B. Berda, and Isabelle M. Crawford-Eng
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chemistry.chemical_classification ,Polymers and Plastics ,Organic Chemistry ,Radical polymerization ,General Physics and Astronomy ,02 engineering and technology ,Polymer ,Nuclear magnetic resonance spectroscopy ,ROMP ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Metathesis ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Monomer ,chemistry ,Polymerization ,Polymer chemistry ,Materials Chemistry ,0210 nano-technology ,Imide - Abstract
We present the synthesis of poly(oxanorbornene imide) single-chain nanoparticles (SCNP) by intrachain radical polymerization of pendant methacryloyl units. Well-defined poly(oxanorbornene imide)s were first prepared via ring-opening metathesis polymerization (ROMP) of methacryloyl-containing monomers. Handling and polymerizing these monomers requires some special care to prevent undesired premature reaction of the methacryloyl groups. Addition of AIBN to dilute solution of the ROMP polymers triggers intrachain radical polymerization of pendant methacryloyl groups, folding the linear polymers into SCNP. Characterization by NMR spectroscopy and SEC confirmed SCNP formation and revealed structure/property relationships related to methacryloyl pendent length and percent incorporation.
- Published
- 2019
17. A structural signature motif enlightens the origin and diversification of nuclear receptors
- Author
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Stéphane Erb, Vincent Laudet, Yassmine Chebaro, Dino Moras, Gabriel V. Markov, Alastair G. McEwen, Isabelle M. L. Billas, Brice Beinsteiner, Sarah Cianférani, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Biologie Intégrative des Modèles Marins (LBI2M), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Spectrométrie de Masse BioOrganique [Strasbourg] (LSMBO), Département Sciences Analytiques et Interactions Ioniques et Biomoléculaires (DSA-IPHC), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Okinawa Institute of Science and Technology Graduate University
- Subjects
Cancer Research ,[SDV]Life Sciences [q-bio] ,Gene regulatory network ,Receptors, Cytoplasmic and Nuclear ,QH426-470 ,Ligands ,Physical Chemistry ,Database and Informatics Methods ,0302 clinical medicine ,Gene Regulatory Networks ,Receptor ,Promoter Regions, Genetic ,Materials ,Genetics (clinical) ,Data Management ,Regulation of gene expression ,0303 health sciences ,Crystallography ,Repertoire ,Physics ,Monomers ,Gene Expression Regulation, Developmental ,Phylogenetic Analysis ,Condensed Matter Physics ,Phylogenetics ,Chemistry ,Physical Sciences ,Crystal Structure ,Dimerization ,Sequence Analysis ,Research Article ,Computer and Information Sciences ,Evolutionary Processes ,Bioinformatics ,Materials Science ,Embryonic Development ,Computational biology ,Retinoid X receptor ,Biology ,Research and Analysis Methods ,03 medical and health sciences ,Interaction network ,Sequence Motif Analysis ,Evolutionary Adaptation ,Genetics ,Electron Density ,Solid State Physics ,Humans ,Evolutionary Systematics ,Amino Acid Sequence ,Enhancer ,Dimers ,Molecular Biology ,Transcription factor ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,Taxonomy ,Evolutionary Biology ,Binding Sites ,Biology and Life Sciences ,Exaptation ,Polymer Chemistry ,Retinoid X Receptors ,Nuclear receptor ,Hepatocyte nuclear factor 4 ,Chemical Properties ,Evolutionary biology ,Oligomers ,Function (biology) ,030217 neurology & neurosurgery ,Transcription Factors - Abstract
Nuclear receptors are ligand-activated transcription factors that modulate gene regulatory networks from embryonic development to adult physiology and thus represent major targets for clinical interventions in many diseases. Most nuclear receptors function either as homodimers or as heterodimers. The dimerization is crucial for gene regulation by nuclear receptors, by extending the repertoire of binding sites in the promoters or the enhancers of target genes via combinatorial interactions. Here, we focused our attention on an unusual structural variation of the α-helix, called π-turn that is present in helix H7 of the ligand-binding domain of RXR and HNF4. By tracing back the complex evolutionary history of the π-turn, we demonstrate that it was present ancestrally and then independently lost in several nuclear receptor lineages. Importantly, the evolutionary history of the π-turn motif is parallel to the evolutionary diversification of the nuclear receptor dimerization ability from ancestral homodimers to derived heterodimers. We then carried out structural and biophysical analyses, in particular through point mutation studies of key RXR signature residues and showed that this motif plays a critical role in the network of interactions stabilizing homodimers. We further showed that the π-turn was instrumental in allowing a flexible heterodimeric interface of RXR in order to accommodate multiple interfaces with numerous partners and critical for the emergence of high affinity receptors. Altogether, our work allows to identify a functional role for the π-turn in oligomerization of nuclear receptors and reveals how this motif is linked to the emergence of a critical biological function. We conclude that the π-turn can be viewed as a structural exaptation that has contributed to enlarging the functional repertoire of nuclear receptors., Author summary The origin of novelties is a central topic in evolutionary biology. A fundamental question is how organisms constrained by natural selection can divert from existing schemes to set up novel structures or pathways. Among the most important strategies are exaptations, which represent pre-adaptation strategies. Many examples exist in biology, at both morphological and molecular levels, such as the one reported here that focuses on an unusual structural feature called the π-turn. It is found in the structure of the most ancestral nuclear receptors RXR and HNF4. The analyses trace back the complex evolutionary history of the π-turn to more than 500 million years ago, before the Cambrian explosion and show that this feature was essential for the heterodimerization capacity of RXR. Nuclear receptor lineages that emerged later in evolution lost the π-turn. We demonstrate here that this loss in nuclear receptors that heterodimerize with RXR was critical for the emergence of high affinity receptors, such as the vitamin D and the thyroid hormone receptors. On the other hand, the conserved π-turn in RXR allowed it to accommodate multiple heterodimer interfaces with numerous partners. This structural exaptation allowed for the remarkable diversification of nuclear receptors.
- Published
- 2021
18. Rare instances of haploid inducer DNA in potato dihaploids and ploidy-dependent genome instability
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Mwaura Livingstone Nganga, Isabelle M. Henry, Benny Ordoñez, Monica Santayana, Merideth Bonierbale, Ek Han Tan, Luca Comai, Kirk R Amundson, and Awais Khan
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0106 biological sciences ,0301 basic medicine ,Genome instability ,Genotype ,Large-Scale Biology Articles ,Introgression ,Plant Science ,Biology ,Haploidy ,01 natural sciences ,Genome ,Genomic Instability ,Polyploidy ,03 medical and health sciences ,chemistry.chemical_compound ,Hybrid ,Solanum tuberosum ,Genetics ,fungi ,food and beverages ,Karyotype ,Cell Biology ,Parthenogenesis ,DNA ,Sperm ,030104 developmental biology ,chemistry ,Ploidy ,010606 plant biology & botany - Abstract
In cultivated tetraploid potato (Solanum tuberosum), reduction to diploidy (dihaploidy) allows for hybridization to diploids and introgression breeding and may facilitate the production of inbreds. Pollination with haploid inducers (HIs) yields maternal dihaploids, as well as triploid and tetraploid hybrids. Dihaploids may result from parthenogenesis, entailing the development of embryos from unfertilized eggs, or genome elimination, entailing missegregation and the loss of paternal chromosomes. A sign of genome elimination is the occasional persistence of HI DNA in some dihaploids. We characterized the genomes of 919 putative dihaploids and 134 hybrids produced by pollinating tetraploid clones with three HIs: IVP35, IVP101, and PL-4. Whole-chromosome or segmental aneuploidy was observed in 76 dihaploids, with karyotypes ranging from 2n = 2x − 1 = 23 to 2n = 2x + 3 = 27. Of the additional chromosomes in 74 aneuploids, 66 were from the non-inducer parent and 8 from the inducer parent. Overall, we detected full or partial chromosomes from the HI parent in 0.87% of the dihaploids, irrespective of parental genotypes. Chromosomal breaks commonly affected the paternal genome in the dihaploid and tetraploid progeny, but not in the triploid progeny, correlating instability to sperm ploidy and to haploid induction. The residual HI DNA discovered in the progeny is consistent with genome elimination as the mechanism of haploid induction.
- Published
- 2021
19. Photoinduced Ligand Exchange Dynamics of a Polypyridyl Ruthenium Complex in Aqueous Solution
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Sylvestre Bonnet, Isabelle M. Dixon, Jérôme Cuny, Fabienne Alary, Photochimie théorique et computationnelle (LCPQ) (PTC), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Leiden Institute of Chemistry, Universiteit Leiden [Leiden], Modélisation, Agrégats, Dynamique (LCPQ) (MAD), Laboratoire de Chimie et Physique Quantiques Laboratoire (LCPQ), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and Universiteit Leiden
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Aqueous solution ,Denticity ,010405 organic chemistry ,Ligand ,Chemistry ,Rational design ,chemistry.chemical_element ,010402 general chemistry ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Ruthenium ,Solvent ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Excited state ,Molecule ,General Materials Science ,[CHIM.COOR]Chemical Sciences/Coordination chemistry ,Physical and Theoretical Chemistry - Abstract
International audience; The understanding of photoinduced ligand exchange mechanisms in polypyridyl ruthenium(II) complexes operating in aqueous solution is of crucial importance to rationalize their photoreactivity. Herein, we demonstrate that a synergetic use of ab initio molecular dynamics simulations and static calculations, both conducted at the DFT level, can provide a full understanding of photosubstitution mechanisms of a monodentate ligand by a solvent water molecule in archetypal ruthenium complexes in explicit water. The simulations show that the photoinduced loss of a monodentate ligand generates an unreactive 16-electron species in a hitherto undescribed pentacoordinated triplet excited state that converts, via an easily accessible crossing point, to a reactive 16-electron singlet ground state, which combines with a solvent water molecule to yield the experimentally observed aqua complex in less than 10 ps. This work paves the way for the rational design of novel photoactive metal complexes relevant for biological applications.
- Published
- 2021
20. Are fetal bilirubin levels associated with the need for neonatal exchange transfusions in hemolytic disease of the fetus and newborn?
- Author
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Renske M. van ‘t Oever, Carolien Zwiers, Isabelle M C Ree, E. J. (Joanne) Verweij, Dick Oepkes, Masja de Haas, and Enrico Lopriore
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medicine.medical_specialty ,intrauterine transfusion ,Bilirubin ,medicine.medical_treatment ,Exchange Transfusion, Whole Blood ,Blood Transfusion, Intrauterine ,Exchange transfusion ,Logistic regression ,Erythroblastosis, Fetal ,chemistry.chemical_compound ,Fetus ,Pregnancy ,Internal medicine ,medicine ,fetal reference values ,Humans ,Hematology ,Obstetrics ,business.industry ,hematology ,Infant, Newborn ,Area under the curve ,Infant ,Obstetrics and Gynecology ,General Medicine ,Odds ratio ,Confidence interval ,chemistry ,Female ,business - Abstract
BACKGROUND Fetal bilirubin is routinely measured at our center when taking a pretransfusion blood sample at intrauterine transfusions in hemolytic disease of the fetus and newborn. However, the clinical value of fetal bilirubin assessment is not well known, and the information is rarely used. We speculated that there could be a role for this measurement in predicting the need for neonatal exchange transfusion. OBJECTIVE This study aimed to evaluate the predictive value of fetal bilirubin for exchange transfusions in severe hemolytic disease of the fetus and newborn. STUDY DESIGN A total of 186 infants with Rh alloantibody–mediated hemolytic disease of the fetus and newborn treated with one or more intrauterine transfusions at the Leiden University Medical Center between January 2006 and June 2020 were included in this observational study. Antenatal and postnatal factors were compared between infants with and without exchange transfusion treatments. The primary outcome was the fetal bilirubin levels before the last intrauterine transfusion in relation to the need for exchange transfusion. RESULTS In a multivariate logistic regression analysis, the fetal bilirubin level before the last intrauterine transfusions (odds ratio, 1.32; 95% confidence interval, 1.09–1.61 per 1 mg/dL) and the total number of intrauterine transfusions (odds ratio, 0.63; 95% confidence interval, 0.44–0.91 per intrauterine transfusion) were independently associated with the need for exchange transfusion. The area under the curve was determined at 0.71. A Youden index was calculated at 0.43. The corresponding fetal bilirubin level was 5 mg/dL and had a sensitivity of 79% and a specificity of 64%. CONCLUSION A high fetal bilirubin level before the last intrauterine transfusion was associated with a high likelihood of neonatal exchange transfusion.
- Published
- 2021
21. On the Spin-State Dependence of Redox Potentials of Spin Crossover Complexes
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Azzedine Bousseksou, Isabelle M. Dixon, Alix Sournia-Saquet, Sylvain Rat, Lionel Salmon, Gábor Molnár, Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse)
- Subjects
Electrochemical reduction ,Spin states ,010405 organic chemistry ,Chemistry ,Spin transition ,Charge (physics) ,010402 general chemistry ,01 natural sciences ,Quantum mechanics ,0104 chemical sciences ,Inorganic Chemistry ,Mathematical methods ,Spin crossover ,Chemical physics ,Oxidation ,Molecule ,[CHIM]Chemical Sciences ,Molecular orbital ,Density functional theory ,Physical and Theoretical Chemistry ,Redox reactions ,Spin-½ - Abstract
International audience; Resistance switching properties of nanoscale junctions of spin crossover molecules have received recently much interest. In many cases, this property has been traced back to the variation of molecular orbital energies upon spin transition. However, one can also expect a substantial reorganization of the molecular structure due to charge localization, which calls for a better understanding of the relationship between the redox potential and the spin state of the molecule. To investigate this issue, we carried out a detailed density functional theory and variable temperature cyclic voltammetry investigation of the benchmark compound [Fe(HB(1,2,4-triazol-1-yl)3)2] in solution. We show that, for a correct thermodynamical picture, it is necessary to take into account the charge transfer-induced electronic and structural reorganization as well as spin equilibria in the oxidized and reduced species.
- Published
- 2020
22. Theoretical study of the full photosolvolysis mechanism of [Ru(bpy)3]2+ : providing a general mechanistic road map for the photochemistry of [Ru(N^N)3]2+-type complexes towards both cis and trans photoproducts
- Author
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Jean-Louis Heully, Isabelle M. Dixon, Fabienne Alary, Paul I. P. Elliott, Adrien Soupart, Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Photochimie théorique et computationnelle (LCPQ) (PTC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), University of Huddersfield, Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3)
- Subjects
010405 organic chemistry ,chemistry.chemical_element ,010402 general chemistry ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Ruthenium ,Inorganic Chemistry ,Bipyridine ,chemistry.chemical_compound ,chemistry ,Mechanism (philosophy) ,[CHIM.COOR]Chemical Sciences/Coordination chemistry ,Physical and Theoretical Chemistry ,Cis–trans isomerism - Abstract
International audience; A complete mechanistic picture for the photochemical release of bpy from the archetypal complex [Ru(bpy)3]2+ is presented for the first time following the description of the ground and lowest triplet potential energy surfaces, as well as their key crossing points, involved in successive elementary steps along pathways towards cis-and trans-[Ru(bpy)2(NCMe)2]2+. This work accounts for two main pathways that are identified involving a) two successive photochemical reactions for photodechelation followed by photorelease of a monodentate bpy ligand, and b) a novel one-photon mechanism in which initial photoexcitation is followed by dechelation, solvent coordination and bpy release processes, all of which occur sequentially within the triplet excited state
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- 2020
23. Sterol Evolution: Cholesterol Synthesis in Animals Is Less a Required Trait Than an Acquired Taste
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Isabelle M. Capell-Hattam and Andrew J. Brown
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0301 basic medicine ,Cholesterol synthesis ,Taste ,Auxotrophy ,Biology ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,parasitic diseases ,Animals ,Caenorhabditis elegans ,Caenorhabditis elegans Proteins ,Cholesterol ,fungi ,Acquired taste ,biology.organism_classification ,Sterol ,Sterols ,030104 developmental biology ,Biochemistry ,chemistry ,Trait ,lipids (amino acids, peptides, and proteins) ,General Agricultural and Biological Sciences ,030217 neurology & neurosurgery - Abstract
Although cholesterol is considered a vital lipid for animals, not all animals can make cholesterol. A new study employing that celebrated elegant worm, Caenorhabditis elegans, investigates mechanisms that evolved in a sterol auxotroph to enable survival without sterol synthesis.
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- 2020
24. Geochemical and geophysical indicators of oil and gas wastewater can trace potential exposure pathways following releases to surface waters
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Douglas B. Kent, Jeanne B. Jaeschke, Aïda M. Farag, Adam Benthem, Adam C. Mumford, Denise M. Akob, Mark A. Engle, Martin A. Briggs, Isabelle M. Cozzarelli, Katherine Skalak, and John W. Lane
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geography ,Strontium ,Environmental Engineering ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Floodplain ,chemistry.chemical_element ,Sediment ,Geophysics ,010501 environmental sciences ,Contamination ,01 natural sciences ,Pollution ,Petroleum seep ,Wastewater ,chemistry ,Environmental Chemistry ,Environmental science ,Waste Management and Disposal ,Surface water ,Groundwater ,0105 earth and related environmental sciences - Abstract
Releases of oil and gas (OG) wastewaters can have complex effects on stream-water quality and downstream organisms, due to sediment-water interactions and groundwater/surface water exchange. Previously, elevated concentrations of sodium (Na), chloride (Cl), barium (Ba), strontium (Sr), and lithium (Li), and trace hydrocarbons were determined to be key markers of OG wastewater releases when combined with Sr and radium (Ra) isotopic compositions. Here, we assessed the persistence of an OG wastewater spill in a creek in North Dakota using a combination of geochemical measurements and modeling, hydrologic analysis, and geophysical investigations. OG wastewater comprised 0.1 to 0.3% of the stream-water compositions at downstream sites in February and June 2015 but could not be quantified in 2016 and 2017. However, OG-wastewater markers persisted in sediments and pore water for 2.5 years after the spill and up to 7.2-km downstream from the spill site. Concentrations of OG wastewater constituents were highly variable depending on the hydrologic conditions. Electromagnetic measurements indicated substantially higher electrical conductivity under the bank adjacent to a seep 7.2 km downstream from the spill site. Geomorphic investigations revealed mobilization of sediment is an important contaminant transport process. Labile Ba, Ra, Sr, and ammonium (NH4) concentrations extracted from sediments indicated sediments are a long-term reservoir of these constituents, both in the creek and on the floodplain. Using the drivers of ecological effects identified at this intensively studied site we identified 41 watersheds across the North Dakota landscape that may be subject to similar episodic inputs from OG wastewater spills. Effects of contaminants released to the environment during OG waste management activities remain poorly understood; however, analyses of Ra and Sr isotopic compositions, as well as trace inorganic and organic compound concentrations at these sites in pore-water provide insights into potentials for animal and human exposures well outside source-remediation zones.
- Published
- 2020
25. On the Possible Coordination on a 3MC State Itself? Mechanistic Investigation Using DFT-Based Methods
- Author
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Jean-Louis Heully, Isabelle M. Dixon, Fabienne Alary, Adrien Soupart, Photochimie théorique et computationnelle (LCPQ) (PTC), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3)
- Subjects
010402 general chemistry ,Ring (chemistry) ,01 natural sciences ,DFT ,Inorganic Chemistry ,chemistry.chemical_compound ,nudged elastic band ,Atomic orbital ,Pyridine ,lcsh:Inorganic chemistry ,Molecular orbital ,[CHIM.COOR]Chemical Sciences/Coordination chemistry ,Lone pair ,photochemistry ,photosolvolysis mechanism ,010405 organic chemistry ,Ligand ,ruthenium polypyridine complex ,molecular orbitals ,lcsh:QD146-197 ,0104 chemical sciences ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Crystallography ,metal-centered excited states ,chemistry ,Excited state ,triplet state reactivity ,Electron configuration - Abstract
Understanding light-induced ligand exchange processes is key to the design of efficient light-releasing prodrugs or photochemically driven functional molecules. Previous mechanistic investigations had highlighted the pivotal role of metal-centered (MC) excited states in the initial ligand loss step. The question remains whether they are equally important in the subsequent ligand capture step. This article reports the mechanistic study of direct acetonitrile coordination onto a 3MC state of [Ru(bpy)3]2+, leading to [Ru(bpy)2(κ1-bpy)(NCMe)]2+ in a 3MLCT (metal-to-ligand charge transfer) state. Coordination of MeCN is indeed accompanied by the decoordination of one pyridine ring of a bpy ligand. As estimated from Nudged Elastic Band calculations, the energy barrier along the minimum energy path is 20 kcal/mol. Interestingly, the orbital analysis conducted along the reaction path has shown that creation of the metallic vacancy can be achieved by reverting the energetic ordering of key dσ* and bpy-based π* orbitals, resulting in the change of electronic configuration from 3MC to 3MLCT. The approach of the NCMe lone pair contributes to destabilizing the dσ* orbital by electrostatic repulsion.
- Published
- 2020
26. Hydrocarbons to carboxyl-rich alicyclic molecules: A continuum model to describe biodegradation of petroleum-derived dissolved organic matter in contaminated groundwater plumes
- Author
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Donald F. Smith, Klaus Schmidt-Rohr, David C. Podgorski, Barbara A. Bekins, Isabelle M. Cozzarelli, Sasha Wagner, Anne M. Kellerman, Phoebe Zito, Aron Stubbins, Xiaoyan Cao, and Robert G. M. Spencer
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Environmental Engineering ,Health, Toxicology and Mutagenesis ,0211 other engineering and technologies ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Alicyclic compound ,Dissolved organic carbon ,Environmental Chemistry ,Waste Management and Disposal ,Chemical composition ,Groundwater ,Alkyl ,0105 earth and related environmental sciences ,chemistry.chemical_classification ,021110 strategic, defence & security studies ,Aromaticity ,Biodegradation ,Pollution ,Hydrocarbons ,Plume ,Biodegradation, Environmental ,Petroleum ,chemistry ,Environmental chemistry ,Water Pollutants, Chemical - Abstract
Relationships between dissolved organic matter (DOM) reactivity and chemical composition in a groundwater plume containing petroleum-derived DOM (DOMHC) were examined by quantitative and qualitative measurements to determine the source and chemical composition of the compounds that persist downgradient. Samples were collected from a transect down the core of the plume in the direction of groundwater flow. An exponential decrease in dissolved organic carbon concentration resulting from biodegradation along the transect correlated with a continuous shift in fluorescent DOMHC from shorter to longer wavelengths. Moreover, ultrahigh resolution mass spectrometry showed a shift from low molecular weight (MW) aliphatic, reduced compounds to high MW, unsaturated (alicyclic/aromatic), high oxygen compounds that are consistent with carboxyl-rich alicyclic molecules. The degree of condensed aromaticity increased downgradient, indicating that compounds with larger, conjugated aromatic core structures were less susceptible to biodegradation. Nuclear magnetic resonance spectroscopy showed a decrease in alkyl (particularly methyl) and an increase in aromatic/olefinic structural motifs. Collectively, data obtained from the combination of these complementary analytical techniques indicated that changes in the DOMHC composition of a groundwater plume are gradual, as relatively low molecular weight (MW), reduced, aliphatic compounds from the oil source were selectively degraded and high MW, alicyclic/aromatic, oxidized compounds persisted.
- Published
- 2020
27. Recent progress in ligand photorelease reaction mechanisms: Theoretical insights focusing on Ru(II) 3MC states
- Author
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Isabelle M. Dixon, Jean-Louis Heully, Adrien Soupart, Fabienne Alary, Paul I. P. Elliott, Photochimie théorique et computationnelle (LCPQ) (PTC), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), University of Huddersfield, Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse)
- Subjects
Reaction mechanism ,Denticity ,010405 organic chemistry ,Ligand ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,3. Good health ,Ruthenium ,Inorganic Chemistry ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Transition metal ,chemistry ,Computational chemistry ,Excited state ,Materials Chemistry ,Theoretical chemistry ,Molecular motion ,Physical and Theoretical Chemistry - Abstract
International audience; The elucidation of reaction mechanisms taking place in the excited state is a current challenge for experimental and theoretical chemists. Ru(II) complexes have a long history for photophysics, and there is currently an increasing interest in their photochemistry. Ru(II) complexes provide a vast field of exploration, whether for synthetic purposes, to trigger molecular motions or to release biologically active components. The excited states involved, especially those of MLCT and MC character, are key to the rationalization of their photophysical and photochemical properties. This review focuses on the recent progress in the latter field through several case studies: i) the archetypes [Ru(bpy)3]2+ and [Ru(tpy)2]2+ first serve for the validation of the theoretical methods we are using; ii) then the study of photorelease of a monodentate ligand provides us with novel mechanistic hypotheses; iii) one step further, studying the photorelease mechanism of a bidentate ligand provides us with novel 3MC states of peculiar flattened geometry; iv) finally, returning to [Ru(bpy)3]2+ itself, we will show that the existence of these states can be generalized and probably represent a major player in the description of photoreactivity mechanisms, for ruthenium and possibly several other transition metals.
- Published
- 2020
28. DIFFERENTIAL ATTENUATION OF TRACE ELEMENTS BY IRON CARBONATES AND IRON HYDROXIDES IN A PETROLEUM-CONTAMINATED PLUME
- Author
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Katherine L. Jones, Brady A. Ziegler, Not Provided, and Isabelle M. Cozzarelli
- Subjects
Trace (semiology) ,chemistry.chemical_compound ,chemistry ,Attenuation ,Mineralogy ,Petroleum ,Environmental science ,Contamination ,Plume - Published
- 2020
29. Sex-specific expression profiles of ecdysteroid biosynthesis and ecdysone response genes in extreme sexual dimorphism of the mealybug Planococcus kraunhiae (Kuwana)
- Author
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Miyuki Muramatsu, Tomohiro Tsuji, Isabelle M. Vea, Chieka Minakuchi, Ken Miura, Akiya Jouraku, Takahiro Shiotsuki, and Sayumi Tanaka
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Male ,0106 biological sciences ,0301 basic medicine ,Life Cycles ,Insecta ,Physiology ,Gene Expression ,Molting ,01 natural sciences ,Database and Informatics Methods ,chemistry.chemical_compound ,Cytochrome P-450 Enzyme System ,Morphogenesis ,Medicine and Health Sciences ,Wings, Animal ,media_common ,Sex Characteristics ,Sexual Differentiation ,Insect Metamorphosis ,Multidisciplinary ,integumentary system ,Metamorphosis, Biological ,Pupa ,Gene Expression Regulation, Developmental ,Eukaryota ,Prothoracic gland ,Juvenile Hormones ,Insects ,Ecdysterone ,Larva ,Insect Proteins ,Medicine ,Female ,Sequence Analysis ,Ecdysone ,Research Article ,medicine.medical_specialty ,animal structures ,Arthropoda ,Bioinformatics ,media_common.quotation_subject ,Science ,Sequence Databases ,Biology ,Research and Analysis Methods ,010603 evolutionary biology ,Halloween genes ,03 medical and health sciences ,Internal medicine ,Genetics ,medicine ,Animals ,Juvenile ,Metamorphosis ,Ecdysteroid ,Sexual Dimorphism ,fungi ,Organisms ,Ecdysteroids ,Biology and Life Sciences ,Invertebrates ,Nymphs ,Biological Databases ,030104 developmental biology ,Endocrinology ,chemistry ,Juvenile hormone ,Physiological Processes ,Ecdysone receptor ,Sequence Alignment ,Zoology ,Entomology ,Developmental Biology - Abstract
Insect molting hormone (ecdysteroids) and juvenile hormone regulate molting and metamorphic events in a variety of insect species. Mealybugs undergo sexually dimorphic metamorphosis: males develop into winged adults through non-feeding, pupa-like stages called prepupa and pupa, while females emerge as neotenic wingless adults. We previously demonstrated, in the Japanese mealybug Planococcus kraunhiae (Kuwana), that the juvenile hormone titer is higher in males than in females at the end of the juvenile stage, which suggests that juvenile hormone may regulate male-specific adult morphogenesis. Here, we examined the involvement of ecdysteroids in sexually dimorphic metamorphosis. To estimate ecdysteroid titers, quantitative RT-PCR analyses of four Halloween genes encoding for cytochrome P450 monooxygenases in ecdysteroid biosynthesis, i.e., spook, disembodied, shadow and shade, were performed. Overall, their expression levels peaked before each nymphal molt. Transcript levels of spook, disembodied and shadow, genes that catalyze the steps in ecdysteroid biosynthesis in the prothoracic gland, were higher in males from the middle of the second nymphal instar to adult emergence. In contrast, the expression of shade, which was reported to be involved in the conversion of ecdysone into 20-hydroxyecdysone in peripheral tissues, was similar between males and females. These results suggest that ecdysteroid biosynthesis in the prothoracic gland is more active in males than in females, although the final conversion into 20-hydroxyecdysone occurs at similar levels in both sexes. Moreover, expression profiles of ecdysone response genes, ecdysone receptor and ecdysone-induced protein 75B, were also analyzed. Based on these expression profiles, we propose that the changes in ecdysteroid titer differ between males and females, and that high ecdysteroid titer is essential for directing male adult development.
- Published
- 2020
30. Unravelling the Mechanism of Excited State Interligand Energy Transfer and the Engineering of Dual-Emission in [Ir(C^N) 2 (N^N)] + Complexes
- Author
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Paul A. Scattergood, Jean-Louis Heully, Samantha J. O. Hardman, Anna Maria Ranieri, Adrian Comia, Luke Charalambou, Craig R. Rice, Fabienne Alary, Isabelle M. Dixon, Paul I. P. Elliott, Massimiliano Massi, Daniel A. W. Ross, University of Huddersfield, Curtin Institute for Functional Materials and Interfaces, University of Manchester [Manchester], Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3)
- Subjects
Physics::General Physics ,010405 organic chemistry ,Chemistry ,Energy transfer ,Dual emission ,chemistry.chemical_element ,[CHIM.INOR]Chemical Sciences/Inorganic chemistry ,010402 general chemistry ,ResearchInstitutes_Networks_Beacons/manchester_institute_of_biotechnology ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Chemical physics ,Excited state ,TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY ,Manchester Institute of Biotechnology ,[CHIM.COOR]Chemical Sciences/Coordination chemistry ,Iridium ,Physical and Theoretical Chemistry ,Phosphorescence ,Mechanism (sociology) - Abstract
Fundamental insights into the mechanism of triplet-excited-state interligand energy transfer dynamics and the origin of dual emission for phosphorescent iridium(III) complexes are presented. The complexes [Ir(C ∧N) 2(N ∧N)] + (HC ∧N = 2-phenylpyridine (1a-c), 2-(2,4-difluorophenyl)pyridine (2a-c), 1-benzyl-4-phenyl-1,2,3-triazole (3a-c); N ∧N = 1-benzyl-4-(pyrid-2-yl)-1,2,3-triazole (pytz, a), 1-benzyl-4-(pyrimidin-2-yl)-1,2,3-triazole (pymtz, b), 1-benzyl-4-(pyrazin-2-yl)-1,2,3-triazole (pyztz, c)) are phosphorescent in room-temperature fluid solutions from triplet metal-to-ligand charge transfer ( 3MLCT) states admixed with either ligand-centered ( 3LC) (1a, 2a, and 2b) or ligand-to-ligand charge transfer ( 3LL′CT) character (1c, 2c, and 3a-c). Particularly striking is the observation that pyrimidine-based complex 1b exhibits dual emission from both 3MLCT/ 3LC and 3MLCT/ 3LL′CT states. At 77 K, the 3MLCT/ 3LL′CT component is lost from the photoluminescence spectra of 1b, with emission exclusively arising from its 3MLCT/ 3LC state, while for 2c switching from 3MLCT/ 3LL′CT- to 3MLCT/ 3LC-based emission is observed. Femtosecond transient absorption data reveal distinct spectral signatures characteristic of the population of 3MLCT/ 3LC states for 1a, 2a, and 2b which persist throughout the 3 ns time frame of the experiment. These 3MLCT/ 3LC state signatures are apparent in the transient absorption spectra for 1c and 2c immediately following photoexcitation but rapidly evolve to yield spectral profiles characteristic of their 3MLCT/ 3LL′CT states. Transient data for 1b reveals intermediate behavior: the spectral features of the initially populated 3MLCT/ 3LC state also undergo rapid evolution, although to a lesser extent than that observed for 1c and 2c, behavior assigned to the equilibration of the 3MLCT/ 3LC and 3MLCT/ 3LL′CT states. Density functional theory (DFT) calculations enabled minima to be optimized for both 3MLCT/ 3LC and 3MLCT/ 3LL′CT states of 1a-c and 2a-c. Indeed, two distinct 3MLCT/ 3LC minima were optimized for 1a, 1b, 2a, and 2b distinguished by upon which of the two C ∧N ligands the excited electron resides. The 3MLCT/ 3LC and 3MLCT/ 3LL′CT states for 1b are very close in energy, in excellent agreement with experimental data demonstrating dual emission. Calculated vibrationally resolved emission spectra (VRES) for the complexes are in excellent agreement with experimental data, with the overlay of spectral maxima arising from emission from the 3MLCT/ 3LC and 3MLCT/ 3LL′CT states of 1b convincingly reproducing the observed experimental spectral features. Analysis of the optimized excited-state geometries enable the key structural differences between the 3MLCT/ 3LC and 3MLCT/ 3LL′CT states of the complexes to be identified and quantified. The calculation of interconversion pathways between triplet excited states provides for the first time a through-space mechanism for a photoinduced interligand energy transfer process. Furthermore, examination of structural changes between the possible emitting triplet excited states reveals the key bond vibrations that mediate energy transfer between these states. This work therefore provides for the first time detailed mechanistic insights into the fundamental photophysical processes of this important class of complexes.
- Published
- 2020
31. INVESTIGATING IRON MINERAL TRANSFORMATIONS AT A HYDROCARBON CONTAMINATED SITE FROM TEMPORAL MEASUREMENTS OF MAGNETIC SUSCEPTIBILITY OF MINERAL PACKETS SUSPENDED IN WELLS
- Author
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Selcen Yokuş, Steve Kilde, Dimitrios Ntarlagiannis, Grayson Maresh, Isabelle M. Cozzarelli, Carl Isaacson, Lee Slater, Miriam Rios-Sanchez, Barbara A. Bekins, Alicia Gohmann, and Estella A. Atekwana
- Subjects
chemistry.chemical_classification ,Mineral ,Hydrocarbon ,chemistry ,Mineralogy ,Environmental science ,Contamination ,Magnetic susceptibility - Published
- 2020
32. Toxicity Assessment of Groundwater Contaminated by Petroleum Hydrocarbons at a Well-Characterized, Aged, Crude Oil Release Site
- Author
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Jennifer T. McGuire, Dalma Martinović-Weigelt, Isabelle M. Cozzarelli, Hannah N. Link, and Barbara A. Bekins
- Subjects
0301 basic medicine ,010501 environmental sciences ,01 natural sciences ,Biological pathway ,03 medical and health sciences ,chemistry.chemical_compound ,Dissolved organic carbon ,Environmental Chemistry ,Groundwater ,0105 earth and related environmental sciences ,Pregnane X receptor ,geography ,geography.geographical_feature_category ,Chemistry ,General Chemistry ,Contamination ,Hydrocarbons ,Biodegradation, Environmental ,Petroleum ,030104 developmental biology ,Environmental chemistry ,Toxicity ,Water Pollutants, Chemical ,Water well - Abstract
Management of petroleum-impacted waters by monitored natural attenuation requires an understanding of the toxicology of both the original compounds released and the transformation products formed during natural breakdown. Here, we report data from a groundwater plume consisting of a mixture of crude oil compounds and transformation products in an effort to bridge the gap between groundwater quality information and potential biological effects of human exposures. Groundwater samples were characterized for redox processes, concentrations of nonvolatile dissolved organic carbon (NVDOC) and total petroleum hydrocarbons in the diesel range, as well as for activation of human nuclear receptors (hNR) and toxicologically relevant transcriptional pathways. Results show upregulation of several biological pathways, including peroxisome proliferator-activated receptor gamma and alpha, estrogen receptor alpha, and pregnane X receptor (PXR) with higher levels of hNR activity observed in more contaminated samples. Our study of affected groundwater contaminated by a crude-oil release 39 years ago shows these types of waters may have the potential to cause adverse impacts on development, endocrine, and liver functioning in exposed populations. Additionally, positive trends in activation of some of the molecular targets (e.g., PXR) with increasing NVDOC concentrations (including polar transformation products) demonstrate the importance of improving our understanding of the toxicity associated with the unknown transformation products present in hydrocarbon-impacted waters. Our results begin to provide insight into the potential toxicity of petroleum-impacted waters, which is particularly timely given the ubiquitous nature of waters impacted by petroleum contamination not only recently but also in the past and the need to protect drinking-water quality.
- Published
- 2018
33. Linear and Third-Order Nonlinear Optical Properties of Fe(η5-C5Me5)(κ2-dppe)- and trans-Ru(κ2-dppe)2-Alkynyl Complexes Containing 2-Fluorenyl End Groups
- Author
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Isabelle M. Dixon, Guillaume Grelaud, Joëlle Rault-Berthelot, Marie P. Cifuentes, Adam Barlow, Olivier Mongin, Graeme J. Moxey, Genmiao Wang, Frédéric Paul, Amédée Triadon, Xinwei Yang, Nicolas Richy, Mark G. Humphrey, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Australian National University (ANU), Photochimie théorique et computationnelle (LCPQ) (PTC), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), CNRS [7106, 1194], Australian Research Council (ARC), ARC, Region Bretagne, Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3)
- Subjects
Third order nonlinear ,Organic Chemistry ,chemistry.chemical_element ,02 engineering and technology ,Chromophore ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Redox ,0104 chemical sciences ,Ruthenium ,Inorganic Chemistry ,Nonlinear optical ,Crystallography ,chemistry ,Atomic electron transition ,Molecule ,[CHIM.COOR]Chemical Sciences/Coordination chemistry ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
International audience; The synthesis and characterization of a set of redox-active iron and ruthenium alkynyl complexes of general formula [[M]Cl(1-p){C equivalent to CC6H5-m(C equivalent to CFlu)(m)}((1+p))][PF6](n) are reported (n = 01; m = 12; [M] = [Fe(eta(5)-C5Me5)(kappa(2)-dppe)] and p = 1 or [M] = [trans-Ru(kappa(2)-dppe)(2)] and p = 01). The linear and third-order nonlinear optical properties of these new organometallic complexes featuring phenylalkynyl ligands functionalized by 2-fluorenyl (Flu) groups were studied in their stable redox states. Their first electronic transitions are assigned with the help of DFT calculations. We show here that these compounds possess significant third-order NLO responses in the near-IR range for molecules of their size. In particular, the remarkably large 2PA activities of the new Ru(II) compounds in the 600-800 nm range (Z-scan) make them attractive nonlinear chromophores. Structure-property studies emphasize the importance of para- versus meta-connection of the 2-fluorenylethynyl units on the phenylalkynyl core and reveal that upon progressing from mono- to bis-alkynyl complexes a further increase of the 2PA cross section can be obtained while maintaining linear transparency in the visible range.
- Published
- 2018
34. Examining Natural Attenuation and Acute Toxicity of Petroleum-Derived Dissolved Organic Matter with Optical Spectroscopy
- Author
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Barbara A. Bekins, Robert G. M. Spencer, Jennifer T. McGuire, Phoebe Zito, David C. Podgorski, Dalma Martinović-Weigelt, and Isabelle M. Cozzarelli
- Subjects
010504 meteorology & atmospheric sciences ,Spectrum Analysis ,Attenuation ,General Chemistry ,010501 environmental sciences ,01 natural sciences ,Fluorescence ,Plume ,Absorbance ,chemistry.chemical_compound ,Petroleum ,Spectrometry, Fluorescence ,chemistry ,Environmental chemistry ,Dissolved organic carbon ,Environmental Chemistry ,Petroleum Pollution ,Spectroscopy ,Groundwater ,Water Pollutants, Chemical ,0105 earth and related environmental sciences - Abstract
Groundwater samples containing petroleum-derived dissolved organic matter (DOMHC) originating from the north oil body within the National Crude Oil Spill Fate and Natural Attenuation Research Site near Bemidji, MN, USA were analyzed by optical spectroscopic techniques (i.e., absorbance and fluorescence) to assess relationships that can be used to examine natural attenuation and toxicity of DOMHC in contaminated groundwater. A strong correlation between the concentration of dissolved organic carbon (DOC) and absorbance at 254 nm (a254) along a transect of the DOMHC plume indicates that a254 can be used to quantitatively assess natural attenuation of DOMHC. Fluorescence components, identified by parallel factor (PARAFAC) analysis, show that the composition of the DOMHC beneath and adjacent to the oil body is dominated by aliphatic, low O/C compounds (“protein-like” fluorescence) and that the composition gradually evolves to aromatic, high O/C compounds (“humic-/fulvic-like” fluorescence) as a function of di...
- Published
- 2018
35. Activation of the central melanocortin system in rats persistently reduces body and fat mass independently of caloric reduction
- Author
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Isabelle M. Côté, Philip J. Scarpace, Sara M. Green, Nihal Tümer, Drake Morgan, and Christy S. Carter
- Subjects
Male ,0301 basic medicine ,medicine.medical_specialty ,Food intake ,Physiology ,Adipose tissue ,Peptides, Cyclic ,Fat mass ,Eating ,03 medical and health sciences ,0302 clinical medicine ,Central melanocortin system ,Physiology (medical) ,Internal medicine ,Hypophagia ,medicine ,Animals ,Caloric Restriction ,Pharmacology ,Control level ,Chemistry ,Body Weight ,Caloric theory ,Melanotan II ,General Medicine ,Melanocortins ,Rats ,030104 developmental biology ,Endocrinology ,medicine.anatomical_structure ,Adipose Tissue ,alpha-MSH ,030217 neurology & neurosurgery ,medicine.drug - Abstract
Recent evidence indicate that melanotan II (MTII) reduces body mass independently of caloric reduction. Because MTII induces a transient hypophagia, caloric reduction is still considered a primary mechanism for MTII-mediated body mass loss. To examine the contribution of caloric reduction to long-term body mass loss in response to MTII, we centrally infused MTII or vehicle in ad libitum fed (MTII and Control) animals in comparison with a group of animals that were pair-fed (PF) to the MTII group. Food intake and body mass were recorded daily, and body composition was assessed biweekly. The present study demonstrates that central MTII-mediated body mass loss is only partially mediated by caloric restriction, and the long-term body mass loss is independent of the initial hypophagia. More importantly, central MTII administration induced a rapid but sustained fat mass loss, independently of caloric reduction. MTII-treated animals preserved their lean/fat mass ratio throughout the study, whereas PF animals underwent a transient reduction of lean/fat mass ratio that was only normalized when food intake returned to Control level. In summary, it can be concluded that activation of the central melanocortin system in rats persistently reduces body and fat mass independently of caloric reduction.
- Published
- 2018
36. A mass balance approach to investigate arsenic cycling in a petroleum plume
- Author
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G.-H. Crystal Ng, Madeline E. Schreiber, Isabelle M. Cozzarelli, and Brady A. Ziegler
- Subjects
Geologic Sediments ,Biogeochemical cycle ,Health, Toxicology and Mutagenesis ,0208 environmental biotechnology ,chemistry.chemical_element ,Aquifer ,02 engineering and technology ,010501 environmental sciences ,Toxicology ,Ferric Compounds ,01 natural sciences ,Arsenic ,chemistry.chemical_compound ,Petroleum Pollution ,Groundwater ,0105 earth and related environmental sciences ,Total organic carbon ,geography ,geography.geographical_feature_category ,Sediment ,General Medicine ,Pollution ,Hydrocarbons ,020801 environmental engineering ,Plume ,Biodegradation, Environmental ,Petroleum ,chemistry ,Environmental chemistry ,Oxidation-Reduction ,Water Pollutants, Chemical ,Geology ,Environmental Monitoring - Abstract
Natural attenuation of organic contaminants in groundwater can give rise to a series of complex biogeochemical reactions that release secondary contaminants to groundwater. In a crude oil contaminated aquifer, biodegradation of petroleum hydrocarbons is coupled with the reduction of ferric iron (Fe(III)) hydroxides in aquifer sediments. As a result, naturally occurring arsenic (As) adsorbed to Fe(III) hydroxides in the aquifer sediment is mobilized from sediment into groundwater. However, Fe(III) in sediment of other zones of the aquifer has the capacity to attenuate dissolved As via resorption. In order to better evaluate how long-term biodegradation coupled with Fe-reduction and As mobilization can redistribute As mass in contaminated aquifer, we quantified mass partitioning of Fe and As in the aquifer based on field observation data. Results show that Fe and As are spatially correlated in both groundwater and aquifer sediments. Mass partitioning calculations demonstrate that 99.9% of Fe and 99.5% of As are associated with aquifer sediment. The sediments act as both sources and sinks for As, depending on the redox conditions in the aquifer. Calculations reveal that at least 78% of the original As in sediment near the oil has been mobilized into groundwater over the 35-year lifespan of the plume. However, the calculations also show that only a small percentage of As (∼0.5%) remains in groundwater, due to resorption onto sediment. At the leading edge of the plume, where groundwater is suboxic, sediments sequester Fe and As, causing As to accumulate to concentrations 5.6 times greater than background concentrations. Current As sinks can serve as future sources of As as the plume evolves over time. The mass balance approach used in this study can be applied to As cycling in other aquifers where groundwater As results from biodegradation of an organic carbon point source coupled with Fe reduction.
- Published
- 2017
37. Weathering of Oil in a Surficial Aquifer
- Author
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Barbara A. Bekins, Isabelle M. Cozzarelli, Mary Jo Baedecker, Jared J. Trost, Robert P. Eganhouse, and Haiping Qi
- Subjects
Total organic carbon ,chemistry.chemical_classification ,geography ,geography.geographical_feature_category ,0208 environmental biotechnology ,Aquifer ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,020801 environmental engineering ,chemistry.chemical_compound ,Hydrocarbon ,chemistry ,Environmental chemistry ,Soil water ,Environmental science ,Petroleum ,Computers in Earth Sciences ,Benzene ,Groundwater ,0105 earth and related environmental sciences ,Water Science and Technology ,Surficial aquifer - Abstract
The composition of crude oil in a surficial aquifer was determined in two locations at the Bemidji, MN, spill site. The abundances of 71 individual hydrocarbons varied within 16 locations sampled. Little depletion of these hydrocarbons (relative to the pipeline oil) occurred in the first 10 years after the spill, whereas losses of 25% to 85% of the total measured hydrocarbons occurred after 30 years. The C6-30 n-alkanes, toluene, and o-xylene were the most depleted hydrocarbons. Some hydrocarbons, such as the n-C10-24 cyclohexanes, tri- and tetra- methylbenzenes, acyclic isoprenoids, and naphthalenes were the least depleted. Benzene was detected at every sampling location 30 years after the spill. Degradation of the oil led to increases in the percent organic carbon and in the δ 13 C of the oil. Another method of determining hydrocarbon loss was by normalizing the total measured hydrocarbon concentrations to that of the most conservative analytes. This method indicated that the total measured hydrocarbons were depleted by 47% to 77% and loss of the oil mass over 30 years was 18% to 31%. Differences in hydrocarbon depletion were related to the depth of the oil in the aquifer, local topography, amount of recharge reaching the oil, availability of electron acceptors, and the presence of less permeable soils above the oil. The results from this study indicate that once crude oil has been in the subsurface for a number of years there is no longer a "starting oil concentration" that can be used to understand processes that affect its fate and the transport of hydrocarbons in groundwater.
- Published
- 2017
38. Linkage Photoisomerization Mechanism in a Photochromic Ruthenium Nitrosyl Complex: New Insights from an MS-CASPT2 Study
- Author
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Isabelle M. Dixon, Leticia González, Francesco Talotta, Martial Boggio-Pasqua, Fabienne Alary, Jean-Louis Heully, institut für Theoretische Chemie, Universität Wien, Universität Wien, Photochimie théorique et computationnelle (LCPQ) (PTC), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3)
- Subjects
Photoisomerization ,010405 organic chemistry ,chemistry.chemical_element ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Potential energy ,0104 chemical sciences ,Computer Science Applications ,Ruthenium ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Photochromism ,Intersystem crossing ,chemistry ,Excited state ,Metastability ,Density functional theory ,Physical and Theoretical Chemistry - Abstract
International audience; The N®O linkage photoisomerization mechanism in a ruthenium nitrosyl complex, [RuCl(NO)(py)4] 2+ , for which a quasi complete photoconversion between the stable nitrosyl (N-bonded) and metastable isonitrosyl (O-bonded) isomers has been observed under continuous irradiation of the crystal at 473 nm (Cormary et al., Acta Cryst. B 2009, 65, 612-623), is investigated using multiconfigurational second-order perturbation theory (CASPT2). The results support efficient intersystem crossing pathways from the initially excited singlet states to the lowest triplet excited state of metal-to-ligand charge transfer character (3 MLCT). The topology of the involved potential energy surfaces corroborates a complex sequential two-photon 2 photoisomerization mechanism involving nonadiabatic processes in agreement with experimental observations and previous density functional theory calculations.
- Published
- 2017
39. Arsenic release to the environment from hydrocarbon production, storage, transportation, use and waste management
- Author
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Madeline E. Schreiber, Isabelle M. Cozzarelli, and Geosciences
- Subjects
Environmental Engineering ,Health, Toxicology and Mutagenesis ,0211 other engineering and technologies ,chemistry.chemical_element ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Arsenic ,Natural gas ,Environmental Chemistry ,Produced water ,Waste Management and Disposal ,0105 earth and related environmental sciences ,chemistry.chemical_classification ,Trace elements ,021110 strategic, defence & security studies ,Waste management ,business.industry ,Unconventional oil ,Biodegradation ,Pollution ,Hydrocarbons ,Unconventional oil and gas ,Hydrocarbon ,chemistry ,Environmental science ,Oil sands ,business ,Groundwater - Abstract
Arsenic (As) is a toxic trace element with many sources, including hydrocarbons such as oil, natural gas, oil sands, and oil- and gas-bearing shales. Arsenic from these hydrocarbon sources can be released to the environment through human activities of hydrocarbon production, storage, transportation and use. In addition, accidental release of hydrocarbons to aquifers with naturally occurring (geogenic) As can induce mobilization of As to groundwater through biogeochemical reactions triggered by hydrocarbon biodegradation. In this paper, we review the occurrence of As in different hydrocarbons and the release of As from these sources into the environment. We also examine the occurrence of As in wastes from hydrocarbon production, including produced water and sludge. Last, we discuss the potential for As release related to waste management, including accidental or intentional releases, and recycling and reuse of these wastes. U.S. Geological Survey Toxic Substances Hydrology ProgramUnited States Geological Survey Published version We gratefully acknowledge Adam Mumford for assistance with data compilation on produced waters and Denise Akob for creating Fig. 1. We also appreciate insightful comments from two anonymous reviewers and Bill Orem of the U.S. Geological Survey. This work was supported by the U.S. Geological Survey Toxic Substances Hydrology Program. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Public domain – authored by a U.S. government employee
- Published
- 2021
40. Degradation of Crude 4-MCHM (4-Methylcyclohexanemethanol) in Sediments from Elk River, West Virginia
- Author
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Douglas B. Chambers, Adam C. Mumford, Jeanne B. Jaeschke, Tracey Spencer, Isabelle M. Cozzarelli, Amisha T. Poret-Peterson, Darren S. Dunlap, Denise M. Akob, and Mary Jo Baedecker
- Subjects
Geologic Sediments ,0208 environmental biotechnology ,02 engineering and technology ,010501 environmental sciences ,Solid-phase microextraction ,01 natural sciences ,chemistry.chemical_compound ,Rivers ,Cyclohexanes ,Environmental Chemistry ,0105 earth and related environmental sciences ,Environmental engineering ,Sediment ,General Chemistry ,West Virginia ,Biodegradation ,Anoxic waters ,020801 environmental engineering ,Biodegradation, Environmental ,chemistry ,4-Methylcyclohexanemethanol ,Environmental chemistry ,Slurry ,Microcosm ,Water Pollutants, Chemical ,Geology - Abstract
In January 2014, approximately 37 800 L of crude 4-methylcyclohexanemethanol (crude MCHM) spilled into the Elk River, West Virginia. To understand the long-term fate of 4-MCHM, we conducted experiments under environmentally relevant conditions to assess the potential for the 2 primary compounds in crude MCHM (1) to undergo biodegradation and (2) for sediments to serve as a long-term source of 4-MCHM. We developed a solid phase microextraction (SPME) method to quantify the cis- and trans-isomers of 4-MCHM. Autoclaved Elk River sediment slurries sorbed 17.5% of cis-4-MCHM and 31% of trans-4-MCHM from water during the 2-week experiment. Sterilized, impacted, spill-site sediment released minor amounts of cis- and up to 35 μg/L of trans-4-MCHM into water, indicating 4-MCHM was present in sediment collected 10 months post spill. In anoxic microcosms, 300 μg/L cis- and 150 μg/L trans-4-MCHM degraded to nondetectable levels in 8-13 days in both impacted and background sediments. Under aerobic conditions, 4-MCHM isomers degraded to nondetectable levels within 4 days. Microbial communities at impacted sites differed in composition compared to background samples, but communities from both sites shifted in response to crude MCHM amendments. Our results indicate that 4-MCHM is readily biodegradable under environmentally relevant conditions.
- Published
- 2017
41. The role of alluvial aquifer sediments in attenuating a dissolved arsenic plume
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Isabelle M. Cozzarelli, Brady A. Ziegler, and Madeline E. Schreiber
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Pollution ,Geologic Sediments ,Iron ,Minnesota ,media_common.quotation_subject ,0208 environmental biotechnology ,Aquifer ,02 engineering and technology ,010501 environmental sciences ,Silt ,01 natural sciences ,Arsenic ,Environmental Chemistry ,Organic matter ,Groundwater ,Geomorphology ,0105 earth and related environmental sciences ,Water Science and Technology ,media_common ,chemistry.chemical_classification ,geography ,geography.geographical_feature_category ,Sediment ,Sorption ,020801 environmental engineering ,Plume ,Biodegradation, Environmental ,Petroleum ,Solubility ,chemistry ,Environmental chemistry ,Oxidation-Reduction ,Water Pollutants, Chemical ,Geology - Abstract
In a crude-oil-contaminated sandy aquifer at the Bemidji site in northern Minnesota, biodegradation of petroleum hydrocarbons has resulted in release of naturally occurring As to groundwater under Fe-reducing conditions. This study used chemical extractions of aquifer sediments collected in 1993 and 2011–2014 to evaluate the relationship between Fe and As in different redox zones (oxic, methanogenic, Fe-reducing, anoxic-suboxic transition) of the contaminated aquifer over a twenty-year period. Results show that 1) the aquifer has the capacity to naturally attenuate the plume of dissolved As, primarily through sorption; 2) Fe and As are linearly correlated in sediment across all redox zones, and a regression analysis between Fe and As reasonably predicted As concentrations in sediment from 1993 using only Fe concentrations; 3) an As-rich “iron curtain,” associated with the anoxic-suboxic transition zone, migrated 30 m downgradient between 1993 and 2013 as a result of the hydrocarbon plume evolution; and 4) silt lenses in the aquifer preferentially sequester dissolved As, though As is remobilized into groundwater from sediment after reducing conditions are established. Using results of this study coupled with historical data, we develop a conceptual model which summarizes the natural attenuation of As and Fe over time and space that can be applied to other sites that experience As mobilization due to an influx of bioavailable organic matter.
- Published
- 2017
42. Significant enhancement of fatty acid composition in seeds of the allohexaploid, Camelina sativa , using <scp>CRISPR</scp> /Cas9 gene editing
- Author
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Peter G. Lynagh, Edgar B. Cahoon, Isabelle M. Henry, Donald P. Weeks, Luca Comai, and Wen Zhi Jiang
- Subjects
Fatty Acid Desaturases ,0106 biological sciences ,0301 basic medicine ,Linolenic acid ,Linoleic acid ,Camelina sativa ,Arabidopsis ,allohexaploid ,Plant Science ,Polymerase Chain Reaction ,01 natural sciences ,Polyploidy ,03 medical and health sciences ,chemistry.chemical_compound ,fatty acid composition ,Arabidopsis thaliana ,CRISPR/Cas9 ,Germ-Line Mutation ,Research Articles ,Gene Editing ,2. Zero hunger ,chemistry.chemical_classification ,biology ,Fatty Acids ,food and beverages ,Fatty acid ,Plants, Genetically Modified ,biology.organism_classification ,Camelina ,Plant Leaves ,Oleic acid ,030104 developmental biology ,oleic acid ,chemistry ,Biochemistry ,Brassicaceae ,Seeds ,CRISPR-Cas Systems ,Agronomy and Crop Science ,RNA, Guide, Kinetoplastida ,Research Article ,010606 plant biology & botany ,Biotechnology ,Polyunsaturated fatty acid - Abstract
Summary The CRISPR/Cas9 nuclease system is a powerful and flexible tool for genome editing, and novel applications of this system are being developed rapidly. Here, we used CRISPR/Cas9 to target the FAD2 gene in Arabidopsis thaliana and in the closely related emerging oil seed plant, Camelina sativa, with the goal of improving seed oil composition. We successfully obtained Camelina seeds in which oleic acid content was increased from 16% to over 50% of the fatty acid composition. These increases were associated with significant decreases in the less desirable polyunsaturated fatty acids, linoleic acid (i.e. a decrease from ~16% to
- Published
- 2017
43. Investigation into the bioavailability of milk protein-derived peptides with dipeptidyl-peptidase IV inhibitory activity using Caco-2 cell monolayers
- Author
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Xiu-Min Chen, Eunice C.Y. Li-Chan, Isabelle M. E. Lacroix, and David D. Kitts
- Subjects
Dipeptidyl Peptidase 4 ,Molecular Sequence Data ,Peptide ,Dipeptidyl peptidase ,0404 agricultural biotechnology ,Humans ,Amino Acid Sequence ,Peptide sequence ,chemistry.chemical_classification ,Dipeptidyl-Peptidase IV Inhibitors ,Chemistry ,Hydrolysis ,Biological Transport ,Biological activity ,04 agricultural and veterinary sciences ,General Medicine ,Milk Proteins ,040401 food science ,Amino acid ,Bioavailability ,Kinetics ,Enzyme ,Diabetes Mellitus, Type 2 ,Biochemistry ,Caco-2 ,Caco-2 Cells ,Peptides ,Food Science - Abstract
In recent years, peptides derived from a variety of dietary proteins have been reported to exhibit inhibitory activity against the dipeptidyl-peptidase IV (DPP-IV) enzyme, a target in the management of type 2 diabetes. While much attention has been given to the production and identification of peptides with DPP-IV inhibitory activity from food proteins, particularly dairy proteins, little is known on the bioavailability of these molecules. In this study, the stability and transport of five previously identified milk-derived peptides (LKPTPEGDL, LPYPY, IPIQY, IPI and WR) and a whey protein isolate (WPI) digest with DPP-IV-inhibitory activity were investigated using Caco-2 cell monolayers as a model system for human intestinal absorption. Even though a small percentage (ranging from 0.05% for LPYPY to 0.47% for WR) of the bioactive peptides added to the apical side was able to cross the monolayer intact, all five peptides investigated were susceptible to peptidase action during the transport study. Conversely, only minor changes to the WPI digest composition were observed. Determination of the DPP-IV inhibitory activity of the peptides and amino acids identified in the apical and basolateral solutions showed that most degradation products were less effective at inhibiting DPP-IV than the peptide they originated from. Findings from this research suggest that the susceptibility of food-derived DPP-IV inhibitory peptides to degradation by intestinal brush border membrane enzymes may alter their biological activity in vivo. Further research should be conducted to enhance the bioavailability of DPP-IV inhibitory peptides.
- Published
- 2017
44. Effectiveness of Sodium Azide Alone Compared to Sodium Azide in Combination with Methyl Nitrosurea for Rice Mutagenesis
- Author
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Areum Chun, Kathie J. Ngo, Isabelle M. Henry, Diana Burkart-Waco, and Thomas H. Tai
- Subjects
0301 basic medicine ,Nitrosourea ,Mutation ,Ethyl methanesulfonate ,Mutant ,food and beverages ,Mutagenesis (molecular biology technique) ,Mutagen ,Context (language use) ,Plant Science ,Biology ,medicine.disease_cause ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,chemistry ,Biochemistry ,medicine ,Sodium azide ,Biotechnology - Abstract
Rice seeds of the temperate japonica cultivar Kitaake were mutagenized with sodium azide alone and in combination with methyl nitrosourea. Using the reduced representation sequencing method Restriction Enzyme Sequence Comparative Analysis (RESCAN), the mutation densities, types and local sequence context were determined in the resulting M2 generation mutants. The results indicate that sodium azide is as effective alone as in combination with methyl nitrosourea in generating mutations in rice. In both cases, GC>AT transitions were the predominant mutation type and similar local sequence contexts were observed (5`-G-G-R-3` for sodium azide, 5`-R-G-R-3` for sodium azide plus methyl nitrosourea). Differences in local sequence context with those reported for another common chemical mutagen, ethyl methanesulfonate, suggests that rice mutant populations developed by combining mutants derived independently from sodium azide and ethyl methanesulfonate may exhibit a broader spectrum of mutations and mutant phenotypes.
- Published
- 2016
45. Biodegradation of a petroleum-derived groundwater plume reveals the compositional continuum of dissolved organic matter
- Author
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Isabelle M. Cozzarelli, Barbara A. Bekins, Robert G. M. Spencer, S. Wagner, Xiaoyan Cao, David C. Podgorski, K. Schmidt-Rohr, Phoebe Zito, Donald F. Smith, and A. Stubbins
- Subjects
chemistry.chemical_compound ,chemistry ,Continuum (measurement) ,Environmental chemistry ,Dissolved organic carbon ,Petroleum ,Environmental science ,Biodegradation ,Groundwater ,Plume - Published
- 2019
46. Bioinformatics of edible yellow mealworm (Tenebrio molitor) proteome reveal the cuticular proteins as promising precursors of dipeptidyl peptidase-IV inhibitors
- Author
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Kento Imai, Vincenzo Fogliano, Isabelle M. E. Lacroix, Irene Dávalos Terán, and Chibuike C. Udenigwe
- Subjects
Mealworm ,Proteome ,In silico ,Biophysics ,Bioinformatics ,Hydrolysate ,Dipeptidyl peptidase ,chemistry.chemical_compound ,Pepsin ,edible insects ,Animals ,Tenebrio ,Food, Health & Consumer Research ,VLAG ,Tenebrio molitor ,hydrophobicity ,Pharmacology ,chemistry.chemical_classification ,Dipeptidyl-Peptidase IV Inhibitors ,biology ,dipeptidyl peptidase-IV ,Computational Biology ,Cell Biology ,bioinformatics ,biology.organism_classification ,Amino acid ,Papain ,Food Quality and Design ,Health & Consumer Research ,cuticular proteins ,chemistry ,Food ,biology.protein ,Peptides ,bioactive peptides ,Food Science - Abstract
Bioinformatics was applied for strategic processing of yellow mealworm (Tenebrio molitor) proteins to produce dipeptidyl peptidase (DPP)-IV inhibiting peptides. In silico analysis of 384 mealworm proteins revealed structural proteins as better precursors of DPP-IV inhibiting peptides, compared with other protein types, after pepsin and papain hydrolysis. This was associated with the higher hydropathicity and amounts of residues associated with DPP-IV inhibition in the structural (cuticular) proteins. In silico, the peptides were mostly released with pepsin than papain. Cuticular (CP) and non-cuticular proteins (NC) were extracted from yellow mealworm and hydrolyzed with pepsin and papain in vitro to validate the virtual findings. CP hydrolysate with papain inhibited DPP-IV the most compared to CP hydrolysate with pepsin, whereas NC hydrolysates were mostly inactive. CP had higher hydrophobic–hydrophilic amino acid ratios and contents of the activity-associated residues than NC. The findings demonstrate the application of bioinformatics in processing proteins for bioactive peptide production. Practical applications: The discovery of bioactive peptides from food proteins is typically based on the classic approach involving working with a small number of protein-protease combinations in vitro. For the first time, this study reported the application of in silico tools in comprehensively studying hundreds of proteins from yellow mealworm (an edible insect) as sources of DPP-IV inhibitors, followed by in vitro processing and validation guided by the results obtained in silico. The advantage of this approach is that it allows for analysis of several protein–protease combinations (with multiple datasets of structural, functional, and bioactivity parameters) in a short time. This work is relevant in advancing research on emerging or alternative proteins as well as structure-informed food protein processing. The bioinformatics approach can be adapted for strategic processing of proteins in the food industry prior to making major resource investments.
- Published
- 2019
47. Predicting anaemia and transfusion dependency in severe alloimmune haemolytic disease of the fetus and newborn in the first 3 months after birth
- Author
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Masja de Haas, Enrico Lopriore, Dick Oepkes, Carolien Zwiers, Rutger A. Middelburg, Isabelle M C Ree, and Johanna G. van der Bom
- Subjects
medicine.medical_specialty ,Anemia, Hemolytic ,Isoantigens ,Bilirubin ,medicine.medical_treatment ,Exchange transfusion ,Kaplan-Meier Estimate ,Hemolysis ,Severity of Illness Index ,Infant, Newborn, Diseases ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Fetus ,Isoantibodies ,Pregnancy ,newborn ,Intensive Care Units, Neonatal ,medicine ,Odds Ratio ,Humans ,Blood Transfusion ,transfusion ,anaemia ,Obstetrics ,business.industry ,Incidence (epidemiology) ,Infant, Newborn ,Infant ,Hematology ,Odds ratio ,Prognosis ,Confidence interval ,alloimmunisation ,chemistry ,030220 oncology & carcinogenesis ,Cohort ,Female ,Immunization ,Disease Susceptibility ,business ,HDFN ,030215 immunology ,Haemolytic disease - Abstract
Infants with haemolytic disease of the fetus and newborn (HDFN) often require erythrocyte transfusions in the first 3 months of life. We aimed to evaluate the incidence, timing and potential predictors of transfusion-dependent anaemia. An observational cohort of 298 term and near-term infants with severe HDFN treated with or without intrauterine transfusion (IUT) was evaluated. Transfusions were administered to 88% (169/193) of infants with IUT and 60% (63/105) without IUT. The following potential predictors were associated with less anaemia: K compared to D immunisation [odds ratio (OR) 0·13, 95% confidence interval (CI): 0·03-0·55], higher reticulocyte count at birth [per 10 parts per thousand (‰) higher, OR 0·99, CI: 0·97-1·00] and exchange transfusion (OR 0·11, 95% CI: 0·03-0·50). Without IUT, these variables were: lower reticulocyte count at birth (per 10‰ lower, OR 1·02, 95% CI: 1·00-1·03), lower maximum bilirubin after birth (per 10 μmol/l lower, OR 1·01, 95% CI: 1·01-1·02) and exchange transfusion (OR 0·07, 95% CI: 0·01-0·20). In conclusion, potential predictors for anaemia in infants with severe HDFN varied between infants treated with and without IUT and are useful for selecting subgroups of infants at increased risk of anaemia.
- Published
- 2019
48. Citric-acid dialysate improves the calcification propensity of hemodialysis patients: A multicenter prospective randomized cross-over trial
- Author
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Bernard Canaud, Andreas Pasch, Adelheid Gauly, Jeroen P. Kooman, Isabelle M Gsponer, Jeroen B van der Net, Karlien J Ter Meulen, Frank M. van der Sande, Natascha J. H. Broers, Constantijn J.A.M. Konings, Matthias Bachtler, Marijke J E Dekker, MUMC+: MA Nefrologie (9), MUMC+: MA Med Staf Artsass Interne Geneeskunde (9), Interne Geneeskunde, RS: NUTRIM - R3 - Respiratory & Age-related Health, RS: Carim - V02 Hypertension and target organ damage, and RS: CARIM other
- Subjects
Male ,Time Factors ,Physiology ,medicine.medical_treatment ,030232 urology & nephrology ,Hemodynamics ,030204 cardiovascular system & hematology ,Cardiovascular Medicine ,law.invention ,0302 clinical medicine ,Randomized controlled trial ,MAINTENANCE HEMODIALYSIS ,law ,Medicine and Health Sciences ,Renal Failure ,Prospective Studies ,Prospective cohort study ,ALL-CAUSE MORTALITY ,Statistical Data ,Bone mineral ,OUTCOMES ,Multidisciplinary ,CALCIUM CONCENTRATIONS ,Statistics ,STAGE RENAL-DISEASE ,STIFFNESS ,Hematology ,Chemistry ,Nephrology ,Cardiovascular Diseases ,BALANCE ,Physical Sciences ,Medicine ,Female ,Hemodialysis ,Research Article ,medicine.medical_specialty ,Science ,PATIENTS RECEIVING HEMODIALYSIS ,Urology ,chemistry.chemical_element ,Calcium ,Citric Acid ,Calcification ,Phosphates ,CITRATE DIALYSATE ,03 medical and health sciences ,Renal Dialysis ,Medical Dialysis ,medicine ,Humans ,Vascular Calcification ,Aged ,business.industry ,Chemical Compounds ,Biology and Life Sciences ,medicine.disease ,Crossover study ,Bicarbonates ,chemistry ,business ,Physiological Processes ,Mathematics - Abstract
INTRODUCTION: The concentration of dialysate calcium (dCa) has been suggested to affect vascular calcification, but evidence is scarce. Calcification propensity reflects the intrinsic capacity of serum to prevent calcium and phosphate to precipitate. The use of citric-acid dialysate may have a beneficial effect on the calcification propensity due to the chelating effect on calcium and magnesium. The aim of this study was to compare the intradialytic and short-term effects of haemodialysis with either standard acetic-acid dialysate with dCa1.50 (A1.5) or dCa1.25 (A1.25), as well as citric-acid dialysate with dCa1.50 (C1.5) in bicarbonate dialysis on the calcification propensity of serum.METHODS: Chronic stable hemodialysis patients were included. This multicenter randomized cross-over study consisted out of a baseline week (A1.5), followed by the randomized sequence of A1.25 or C1.5 for one week after which the alternate treatment was provided after a washout week with A1.5. Calcification propensity of serum was assessed by time-resolved nephelometry where the T50 reflects the transition time between formation of primary and secondary calciprotein particles.RESULTS: Eighteen patients (median age 70 years) completed the study. Intradialytic change in T50 was increased with C1.5 (121 [90-152]min) compared to A1.25 (83 [43-108]min, pCONCLUSION: Calcification propensity, as measured by the change in T50, improved significantly during treatment in C1.5 compared to A1.25 and A1.5. Long-term studies are needed to investigate the effects of different dialysate compositions concentrations on vascular calcification and bone mineral disorders.
- Published
- 2019
49. Investigation into the potential of commercially available lesser mealworm (A. diaperinus) protein to serve as sources of peptides with DPP-IV inhibitory activity
- Author
-
Irene Dávalos Terán, Harry J. Wichers, Isabelle M. E. Lacroix, and Vincenzo Fogliano
- Subjects
Mealworm ,Dipeptidyl-peptidase IV inhibitors ,hydrolysates ,Proteases ,in vitro digestion ,Industrial and Manufacturing Engineering ,Hydrolysate ,lesser mealworm (A. diaperinus) protein ,0404 agricultural biotechnology ,Functional food ,Thermolysin ,Enzymatic hydrolysis ,Potency ,VLAG ,Food, Health & Consumer Research ,2. Zero hunger ,chemistry.chemical_classification ,biology ,04 agricultural and veterinary sciences ,biology.organism_classification ,040401 food science ,Health & Consumer Research ,Enzyme ,Food Quality and Design ,chemistry ,Biochemistry ,Food ,type 2 diabetes ,Food Science - Abstract
Food-derived peptides are known to possess inhibitory activity against the dipeptidyl-peptidase IV (DPP-IV) enzyme, a target in the management of type 2 diabetes. While proteins from commonly consumed food commodities have been investigated as precursors of DPP-IV-inhibiting peptides, studies on novel protein sources, such as those from insects, are sparse. This research aimed to determine if DPP-IV inhibitors can be generated upon in vitro digestion or enzymatic hydrolysis of lesser mealworm protein isolate and concentrate. Treatment of the proteins with digestive enzymes and proteases generated hydrolysates with varying potency, thermolysin being the most effective at releasing active peptides (IC 50 = 0.63 and 0.60 mg mL −1 for the isolate and concentrate). Ultrafiltration of the thermolysin-treated hydrolysates did not significantly improve the potency. This study shows that DPP-IV inhibitors can be generated from lesser mealworm protein and provides insight on the potential of insects to serve as functional food ingredients.
- Published
- 2019
50. EVALUATING THE EFFECTS CO-CONTAMINANTS ETHANOL AND NITRATE ON BTEX BIODEGRADATION USING A MULTI-SPECIES NUMERICAL MODEL
- Author
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Jennifer T. McGuire, Isabelle M. Cozzarelli, John Koellmann, Mantha S. Phanikumar, and Brady A. Ziegler
- Subjects
chemistry.chemical_compound ,Ethanol ,chemistry ,Nitrate ,Environmental chemistry ,Multi species ,Environmental science ,BTEX ,Biodegradation ,Contamination - Published
- 2019
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