17 results on '"Kerros ME"'
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2. Bacterial community composition and potential controlling mechanisms along a trophic gradient in a barrier reef system
- Author
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Weinbauer, MG, primary, Kerros, ME, additional, Motegi, C, additional, Wilhartitz, IC, additional, Rassoulzadegan, F, additional, Torréton, JP, additional, and Mari, X, additional
- Published
- 2010
- Full Text
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3. Bacterial colonization of transparent exopolymeric particles in mesocosms under different turbulence intensities and nutrient conditions
- Author
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Pedrotti, ML, primary, Beauvais, S, additional, Kerros, ME, additional, Iversen, K, additional, and Peters, F, additional
- Published
- 2009
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4. Effect of seawater–freshwater cross-transplantations on viral dynamics and bacterial diversity and production
- Author
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Bonilla-Findji, O, primary, Rochelle-Newall, E, additional, Weinbauer, MG, additional, Pizay, MD, additional, Kerros, ME, additional, and Gattuso, JP, additional
- Published
- 2009
- Full Text
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5. Pollution by anthropogenic microfibers in North-West Mediterranean Sea and efficiency of microfiber removal by a wastewater treatment plant.
- Author
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Pedrotti ML, Petit S, Eyheraguibel B, Kerros ME, Elineau A, Ghiglione JF, Loret JF, Rostan A, and Gorsky G
- Abstract
The widespread pollution from the release of microfibers is an emerging concern as they are a potential threat to the environment. Their identification in samples in terms of quantity and pathways remain a challenge as contamination can be a major source of error. A systematic study of synthetic microfibers (MFs) has been carried out in different environmental compartments of an urban area and in the surface waters of the northwestern Mediterranean. The quantity, size and type of polymer of MFs were recorded in air, in waste water from a domestic washing machine, at the inlet and outlet of the Haliotis urban wastewater treatment plant (WWTP) in Nice (Provence Alpes Côte-d'Azur, France) and in a variety of coastal and offshore areas. The results showed that MFs released by clothes during washing (on average of 13 × 10
6 MFs per m3 ) are an important emitter of microplastics. Despite its high removal efficiency (87.5% to 98.5%) by Haliotis, a large number of MFs, estimated at 4.3 billion, enter the marine environment daily from the treatment plant. The attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) characterization of the raw materials showed that 14 to 50% of fibers are synthetic, mostly polyester and polyamide, the remaining 35 to 72% being natural polymers (cotton, wool) or manufactured by processing natural polymers (especially cellulose). MFs were found in all environmental compartments studied and appear to be widespread in coastal and offshore surface waters with concentrations varying from 2.6 × 103 to 3.70 × 104 m-3 . The sources of MFs in the marine environment are multiple, with laundry fibers discharges from WWTP and the atmospheric transport of urban fibers are among the main pathways., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)- Published
- 2021
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6. A machine learning algorithm for high throughput identification of FTIR spectra: Application on microplastics collected in the Mediterranean Sea.
- Author
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Kedzierski M, Falcou-Préfol M, Kerros ME, Henry M, Pedrotti ML, and Bruzaud S
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- Environmental Monitoring methods, Humans, Mediterranean Sea, Algorithms, Machine Learning, Plastics analysis, Plastics chemistry, Water Pollutants, Chemical analysis, Water Pollutants, Chemical chemistry
- Abstract
The development of methods to automatically determine the chemical nature of microplastics by FTIR-ATR spectra is an important challenge. A machine learning method, named k-nearest neighbors classification, has been applied on spectra of microplastics collected during Tara Expedition in the Mediterranean Sea (2014). To realize these tests, a learning database composed of 969 microplastic spectra has been created. Results show that the machine learning process is very efficient to identify spectra of classical polymers such as poly(ethylene), but also that the learning database must be enhanced with less common microplastic spectra. Finally, this method has been applied on more than 4000 spectra of unidentified microplastics. The verification protocol showed less than 10% difference in the results between the proposed automated method and a human expertise, 75% of which can be very easily corrected., (Copyright © 2019 Elsevier Ltd. All rights reserved.)
- Published
- 2019
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7. Microplastics in Mediterranean Sea: A protocol to robustly assess contamination characteristics.
- Author
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Kedzierski M, Villain J, Falcou-Préfol M, Kerros ME, Henry M, Pedrotti ML, and Bruzaud S
- Subjects
- Environmental Monitoring, Mediterranean Sea, Particle Size, Reproducibility of Results, Spectrophotometry, Spectroscopy, Fourier Transform Infrared, Environmental Pollution analysis, Plastics analysis, Seawater analysis, Water Pollutants, Chemical analysis
- Abstract
The study of microplastic pollution involves multidisciplinary analyses on a large number of microplastics. Therefore, providing an overview of plastic pollution is time consuming and, despite high throughput analyses, remains a major challenge. The objective of this study is to propose a protocol to determine how many microplastics must be analyzed to give a representative view of the particle size distribution and chemical nature, and calculate the associated margin error. Based on microplastic data from Tara Mediterranean campaign, this approach is explained through different examples. In this particular case, the results show that only 3% of the collected microplastics need to be analyzed to give a precise view on the scale of the North West Mediterranean Basin (error <5%), and 17.7% to give an overview manta per manta (error <10%). This approach could be an important practical contribution to microplastic studies., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
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8. Effects of sodium azide on the abundance of prokaryotes and viruses in marine samples.
- Author
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Winter C, Kerros ME, and Weinbauer MG
- Subjects
- Cell Count, Flow Cytometry, Seawater, Statistics, Nonparametric, Marine Biology methods, Prokaryotic Cells drug effects, Sodium Azide pharmacology, Tissue Preservation methods, Viruses drug effects
- Abstract
Flow cytometry is set to become the standard method for enumerating prokaryotes and viruses in marine samples. However, the samples need to be flash-frozen in liquid nitrogen directly after aldehyde fixation. Because liquid nitrogen may not always be available, we tested the potential of sodium azide as a preservative for prokaryotes and viruses in marine samples as a possible alternative. For that we conducted incubation experiments with untreated and sodium azide treated marine water samples at 4°C and room temperature. The data indicate that sodium azide cannot be used to maintain marine samples used for the enumeration of prokaryotes and viruses.
- Published
- 2012
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9. Early development and molecular plasticity in the Mediterranean sea urchin Paracentrotus lividus exposed to CO2-driven acidification.
- Author
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Martin S, Richier S, Pedrotti ML, Dupont S, Castejon C, Gerakis Y, Kerros ME, Oberhänsli F, Teyssié JL, Jeffree R, and Gattuso JP
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- Animals, Calcification, Physiologic, Calcium metabolism, Embryo, Nonmammalian drug effects, Female, Fertilization drug effects, Gene Expression Regulation, Larva cytology, Male, Mediterranean Sea, Oceans and Seas, Carbon Dioxide pharmacology, Hydrogen-Ion Concentration, Larva drug effects, Paracentrotus drug effects, Paracentrotus embryology, Paracentrotus growth & development
- Abstract
Ocean acidification is predicted to have significant effects on benthic calcifying invertebrates, in particular on their early developmental stages. Echinoderm larvae could be particularly vulnerable to decreased pH, with major consequences for adult populations. The objective of this study was to understand how ocean acidification would affect the initial life stages of the sea urchin Paracentrotus lividus, a common species that is widely distributed in the Mediterranean Sea and the NE Atlantic. The effects of decreased pH (elevated P(CO(2))) were investigated through physiological and molecular analyses on both embryonic and larval stages. Eggs and larvae were reared in Mediterranean seawater at six pH levels, i.e. pH(T) 8.1, 7.9, 7.7, 7.5, 7.25 and 7.0. Fertilization success, survival, growth and calcification rates were monitored over a 3 day period. The expression of genes coding for key proteins involved in development and biomineralization was also monitored. Paracentrotus lividus appears to be extremely resistant to low pH, with no effect on fertilization success or larval survival. Larval growth was slowed when exposed to low pH but with no direct impact on relative larval morphology or calcification down to pH(T) 7.25. Consequently, at a given time, larvae exposed to low pH were present at a normal but delayed larval stage. More surprisingly, candidate genes involved in development and biomineralization were upregulated by factors of up to 26 at low pH. Our results revealed plasticity at the gene expression level that allows a normal, but delayed, development under low pH conditions.
- Published
- 2011
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10. Response of the calcifying coccolithophore Emiliania huxleyi to low pH/high pCO 2 : from physiology to molecular level.
- Author
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Richier S, Fiorini S, Kerros ME, von Dassow P, and Gattuso JP
- Abstract
The emergence of ocean acidification as a significant threat to calcifying organisms in marine ecosystems creates a pressing need to understand the physiological and molecular mechanisms by which calcification is affected by environmental parameters. We report here, for the first time, changes in gene expression induced by variations in pH/pCO
2 in the widespread and abundant coccolithophore Emiliania huxleyi . Batch cultures were subjected to increased partial pressure of CO2 (pCO2 ; i.e. decreased pH), and the changes in expression of four functional gene classes directly or indirectly related to calcification were investigated. Increased pCO2 did not affect the calcification rate and only carbonic anhydrase transcripts exhibited a significant down-regulation. Our observation that elevated pCO2 induces only limited changes in the transcription of several transporters of calcium and bicarbonate gives new significant elements to understand cellular mechanisms underlying the early response of E. huxleyi to CO2 -driven ocean acidification.- Published
- 2011
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11. Matrix therapy in regenerative medicine, a new approach to chronic wound healing.
- Author
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Barbier-Chassefière V, Garcia-Filipe S, Yue XL, Kerros ME, Petit E, Kern P, Saffar JL, Papy-Garcia D, Caruelle JP, and Barritault D
- Subjects
- Animals, Biomimetic Materials chemistry, Collagen biosynthesis, Dextrans chemistry, Epithelium growth & development, Glycosaminoglycans chemistry, Glycosaminoglycans therapeutic use, Heparitin Sulfate, Mice, Biomimetic Materials therapeutic use, Dextrans therapeutic use, Extracellular Matrix Proteins metabolism, Regenerative Medicine methods, Skin Ulcer therapy, Wound Healing drug effects
- Abstract
Nonhealing wounds remain a major health problem whose treatment is challenging and costly. Treatments based on cells or growth factors are still not very effective. We developed an entirely novel strategy consisting in treatment of the wound-tissue matrix with biopolymers engineered to mimic heparan sulfates called OTR4120. This compound was dextran polymer with sulfated and carboxymethyl groupments. After binding to matrix proteins, the heparan-sulfate-mimicking polymer protects the microenvironment, maintaining the normal production of signals and growth factors needed for healing to occur. Here, we show that a specific biopolymer accelerates ulcer closure and improves re-epithelialization and dermal-matrix-component remodeling. OTR4120 treatment was associated with faster maturation of epidermal structures, most notably regarding the number of epithelial-cell layers, and with an appearance that more closely resembled normal skin. Treatment had also a main effect on collagen I and III expression. Necrotic skin ulcers induced in mice with doxorubicin recovered normal collagen levels and organization, with no evidence of fibrosis. Thus, appropriate polymer-based matrix therapy is a valid and simple alternative to regenerative medicine.
- Published
- 2009
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12. Light-dependent transcriptional regulation of genes of biogeochemical interest in the diploid and haploid life cycle stages of Emiliania huxleyi.
- Author
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Richier S, Kerros ME, de Vargas C, Haramaty L, Falkowski PG, and Gattuso JP
- Subjects
- Diploidy, Haploidy, Darkness, Eukaryota physiology, Gene Expression Profiling, Light
- Abstract
The expression of genes of biogeochemical interest in calcifying and noncalcifying life stages of the coccolithophore Emiliania huxleyi was investigated. Transcripts potentially involved in calcification were tested through a light-dark cycle. These transcripts were more abundant in calcifying cells and were upregulated in the light. Their application as potential candidates for in situ biogeochemical proxies is also suggested.
- Published
- 2009
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13. Structure-activity studies of heparan mimetic polyanions for anti-prion therapies.
- Author
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Ouidja MO, Petit E, Kerros ME, Ikeda Y, Morin C, Carpentier G, Barritault D, Brugère-Picoux J, Deslys JP, Adjou K, and Papy-Garcia D
- Subjects
- Animals, Anions, Binding Sites, Biomimetic Materials administration & dosage, Biomimetic Materials therapeutic use, Cell Line, Humans, Prion Diseases drug therapy, Prion Diseases metabolism, Protein Binding, Structure-Activity Relationship, Heparitin Sulfate administration & dosage, Heparitin Sulfate chemistry, Neurons drug effects, Neurons metabolism
- Abstract
Polysulfated molecules, as the family of heparan mimetics (HMs) and pentosan polysulfate, are considered among the more promising drugs used in experimental models of prion diseases. Regardless of their therapeutic potential, structure-function studies on these polyanions are still missing. Here, we report the syntheses of a library of HMs of different molecular sizes, containing various sulfation and carboxylation levels, and substituted or not by different hydrophobic cores. The HMs capacities to inhibit the accumulation of PrPres in chronically infected cells (ScGT1-7) and their PrPc binding abilities were examined. Our results showed that an optimal size and sulfation degree are needed for optimum activity, that incorporation of hydrophobic moieties increases compounds efficacy and that the presence of carboxymethyl moieties decreases it. These structural features should be considered on the modelling of polyanionic compounds for optimum anti-prion activities and for advancing in the understanding the mechanisms involved in their biological actions.
- Published
- 2007
- Full Text
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14. Virus attachment to transparent exopolymeric particles along trophic gradients in the southwestern lagoon of New Caledonia.
- Author
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Mari X, Kerros ME, and Weinbauer MG
- Subjects
- Geologic Sediments virology, New Caledonia, Organic Chemicals chemistry, Particle Size, Viruses chemistry, Water Microbiology, Polymers chemistry, Seawater virology, Viruses growth & development
- Abstract
Viruses on organic aggregates such as transparent exopolymeric particles (TEP) are not well investigated. The number of TEP-attached viruses was assessed along trophic gradients in the southwestern lagoon of New Caledonia by determining the fraction of viruses removed after magnetic isolation of TEP. In order to isolate TEP magnetically, TEP were formed in the presence of magnetic beads from submicrometer precursors collected along the trophic gradients. The mixed aggregates of TEP-beads-viruses were removed from solution with a magnetic field. The percentage of viruses associated with newly formed TEP averaged 8% (range, 3 to 13%) for most of the stations but was higher (ca. 30%) in one bay characterized by the low renewal rate of its water mass. The number of viruses (N) attached to TEP varied as a function of TEP size (d [in micrometers]) according to the formulas N = 100d(1.60) and N = 230d(1.75), respectively, for TEP occurring in water masses with short (i.e., <40 days) and long (i.e., >40 days) residence times. These two relationships imply that viral abundance decreases with TEP size, and they indicate that water residence time influences viral density and virus-bacterium interactions within aggregates. Our data suggest that the fraction of viruses attached to TEP is highest in areas characterized by a low renewal rate of the water mass and can constitute at times a significant fraction of total virus abundance. Due to the small distance between viruses and hosts on TEP, these particles may be hot spots for viral infection.
- Published
- 2007
- Full Text
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15. RGTA OTR4120, a heparan sulfate mimetic, is a possible long-term active agent to heal burned skin.
- Author
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Garcia-Filipe S, Barbier-Chassefiere V, Alexakis C, Huet E, Ledoux D, Kerros ME, Petit E, Barritault D, Caruelle JP, and Kern P
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- Animals, Burns complications, Burns metabolism, Burns pathology, Cicatrix etiology, Cicatrix metabolism, Fibrillar Collagens biosynthesis, Humans, Male, Matrix Metalloproteinase 2 biosynthesis, Matrix Metalloproteinase 9 biosynthesis, Rats, Rats, Nude, Skin metabolism, Skin pathology, Time Factors, Biomimetic Materials pharmacology, Burns drug therapy, Cicatrix prevention & control, Heparitin Sulfate pharmacology, Wound Healing drug effects
- Abstract
Burn-related skin fibrosis leads to loss of tissue function and hypertrophic scar formation with damaging consequences for the patient. There is therefore a great need for an efficient agent to treat burned skin. We report that ReGeneraTing Agent (RGTA) reduces burn-induced skin alteration. The tissue-regenerating effect of RGTA OTR4120 was evaluated after 1-6 days and after 10 months in a rat skin burn model. This effect was also examined in vitro using fibroblasts isolated from control and 6-day-old burned skins. We measured production of dermal collagen I, III, and V and activities of metalloproteinases 2 and 9 (MMP-2 and MMP-9). Ratio of collagen III over collagen I production increased 6 days after the burn, because of a decrease in collagen I production. After 10 months, ratio of collagen III over collagen I in burn sites was still increased compared with control skin, because of an increase in collagen III production. Both abnormalities were corrected by OTR4120. OTR4120 increased pro- and active MMP-2 and MMP-9, compared with healthy and burned controls and therefore accelerated remodeling. Similar data were obtained with cultured fibroblasts from healthy and burned skins. OTR4120 enhanced healing in short- and long-term after burns, reducing the formation of fibrotic tissue, and then represents a potential agent to improve burned skin healing., ((c) 2006 Wiley Periodicals, Inc.)
- Published
- 2007
- Full Text
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16. Dominant negative effectors of heparin affin regulatory peptide (HARP) angiogenic and transforming activities.
- Author
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Bernard-Pierrot I, Delbé J, Rouet V, Vigny M, Kerros ME, Caruelle D, Raulais D, Barritault D, Courty J, and Milhiet PE
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- 3T3 Cells, Amino Acid Sequence, Animals, Antineoplastic Agents pharmacology, Aorta, Carrier Proteins chemistry, Carrier Proteins genetics, Cytokines chemistry, Cytokines genetics, DNA Replication, Endothelium, Vascular drug effects, Humans, Kinetics, Mice, Mice, Nude, Molecular Sequence Data, Neoplasms blood supply, Neovascularization, Physiologic drug effects, Peptide Fragments chemistry, Recombinant Proteins metabolism, Carrier Proteins physiology, Cell Transformation, Neoplastic, Cytokines physiology, Endothelium, Vascular physiology, Growth Substances physiology, Neoplasms prevention & control, Neovascularization, Physiologic physiology, Peptide Fragments pharmacology
- Abstract
Heparin affin regulatory peptide (HARP) is an heparin-binding growth factor, highly expressed in several primary human tumors and considered as a rate-limiting angiogenic factor in tumor growth, invasion, and metastasis. Implication of this protein in carcinogenesis is linked to its mitogenic, angiogenic, and transforming activities. Recently, we have demonstrated that the C-terminal residues 111-136 of HARP are required for its mitogenic and transforming activities (Bernard-Pierrot, I., Delbe, J., Caruelle, D., Barritault, D., Courty, J., and Milhiet, P. E. (2001) J. Biol. Chem. 276, 12228-12234). In this paper, HARP deleted of its last 26 amino acids was shown to act as a dominant negative effector for its mitogenic, angiogenic, transforming, and tumor-formation activities by heterodimerizing with the wild type protein. Similarly, the synthetic corresponding peptide P111-136 displayed in vitro inhibition of wild type HARP activities, but in this case, the inhibition was mainly explained by the competition of the peptide with HARP for the binding to the extracellular domain of the high affinity ALK receptor.
- Published
- 2002
- Full Text
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17. Immunoassay for measuring the heparin-binding growth factors HARP and MK in biological fluids.
- Author
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Soulié P, Héroult M, Bernard I, Kerros ME, Milhiet PE, Delbé J, Barritault D, Caruelle D, and Courty J
- Subjects
- Adult, Aged, Animals, Carrier Proteins blood, Case-Control Studies, Cattle, Cells, Cultured, Cytokines blood, Endothelium, Vascular cytology, Endothelium, Vascular metabolism, Female, Humans, Male, Middle Aged, Midkine, Neoplasms blood, Reproducibility of Results, Sensitivity and Specificity, Carrier Proteins metabolism, Cytokines metabolism, Enzyme-Linked Immunosorbent Assay methods
- Abstract
Heparin-affin regulatory peptide (HARP) and Midkine (MK) belong to a family of growth/differentiation factors that have a high affinity for heparin. The involvement of these molecules in various proliferative diseases prompted us to develop an assay for measuring the concentrations of these factors in biological fluids and culture media. This report describes an immunoassay that uses only commercially available materials, based on the high affinity of certain molecules for heparin. It consists of adsorbing heparin-BSA covalent complexes to microtiter plate wells and to quantify the heparin bound HARP or MK by using appropriate antibody. The method is specific and measures concentrations ranging from 40-1200 pg/mL HARP and from 25-1200 pg/mL MK and various parameters are investigated. The within-assay coefficient of variation was less than 5% for both assays. The method was checked by measuring the concentrations of these growth factors in the sera of healthy humans and in patients with cancer. As previously reported, we confirmed that the serum concentrations of MK are higher in patients with tumours (n = 139) than in controls (n = 19). The synthesis of HARP and MK by various cells in culture was also analysed.
- Published
- 2002
- Full Text
- View/download PDF
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