24 results on '"Bradley, T. M."'
Search Results
2. Antimicrobial peptide hepcidin contributes to host defense of Centropristis striata against Vibrio harveyi challenge.
- Author
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Ma, Xiaowan, Qiao, Ying, Shao, Yanxiang, and Chen, Chao
- Abstract
Hepcidins are small cysteine-rich antimicrobial peptides that play a vital role in immunity against pathogen invasion. Here, a hepcidin (Cshep) from Centropristis striata was described, which is considered as a valuable aquaculture marine species in China. The open reading frame consisted of 273 bp. Eight conserved cysteine residues were identified. Phylogenetic analysis showed that Cshep had a relatively close relationship with the hepcidin from Epinephelus moara. Quantitative real-time PCR analysis demonstrated that Cshep was highly expressed in liver and significantly up-regulated when challenged with Vibrio harveyi. In addition, the synthetic Cshep peptide had a high antimicrobial activity against V. harveyi, but low against other pathogenic bacteria tested in this study. The killing kinetics analysis revealed that Cshep had a fast bactericidal effect on V. harveyi. These results suggested that Cshep may be involved in the immune response of C. striata against V. harveyi infection. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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3. Falls in older adults with cancer: an updated systematic review of prevalence, injurious falls, and impact on cancer treatment.
- Author
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Sattar, S., Haase, K., Kuster, S., Puts, M., Spoelstra, S., Bradley, C., Wildes, T. M., and Alibhai, S.
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CANCER patients ,OLDER people ,CANCER treatment ,GERIATRIC oncology ,OLDER patients - Abstract
Purpose: This update of our 2016 systematic review answers the following questions: (1) How often do older adults with cancer fall? (2) What are the predictors for falls? (3) What are the rates and predictors of injurious falls? (4) What are the circumstances and outcomes of falls? (5) How do falls in older patients affect subsequent cancer treatment? and a new research question, (6) Which fall reduction interventions are efficacious in this population? Methods: MEDLINE, PubMed, CINAHL, and Embase were searched (September 2015–January 25, 2019). Eligible studies included clinical trials and cohort, case-control, and cross-sectional studies published in English in which the sample (or subgroup) included adults aged ≥ 60, with cancer, in whom falls were examined as an outcome. Results: A total of 2521 titles were reviewed, 67 full-text articles were screened for eligibility, and 30 new studies were identified. The majority involved the outpatient setting (n = 19) utilizing cross-sectional method (n = 18). Sample size ranged from 21 to 17,958. Fall rates ranged from 1.52 to 3.41% per 1000 patient days (inpatient setting) and from 39%/24 months to 64%/12 months (outpatient setting). One out of the 6 research questions contributed to a new finding: one study reported that 1 in 20 older patients experienced impact on cancer treatment due to falls. No consistent predictors for falls/fall injuries and no studies on fall reduction interventions in the geriatric oncology setting were identified. Conclusion: This updated review highlights a new gap in knowledge pertaining to interventions to prevent falls. Additionally, new knowledge also emerged in terms of impact of falls on cancer treatment; however, further research may increase generalizability. Falls and fall-related injuries are common in older adults with cancer and may affect subsequent cancer treatment. Further studies on predictors of falls, subsequent impacts, and fall reduction in the oncology setting are warranted. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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4. Acoustic Conditioning System Development and Conditioning Experiments on Black Seabreams in the Xiangshan Bay Sea Ranch.
- Author
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Hu, Qingsong, Rahman, Hafiz Abd ur, Jiang, Yazhou, Zhang, Shouyu, and Shentu, Jikang
- Abstract
Attracting released hatchery-reared fish to designated areas during the growth process is vital to realize the objectives of sea ranching. Based on the bottom artificial reefs and surface kelp culture facilities in the Xiangshan Bay sea ranch, we proposed systematic techniques related to acoustic conditioning of the black seabream (
Sparus macrocephalus ). Experiments conducted in 12 m × 10 m × 1.6 m ponds on Xixuan Island showed that black seabream was positively sensitive to 500-600 Hz periodic signals. Conditioned responses were apparent after 8 d. Two to three days were required for recovery of the memory of a conditioned response after a 20-day interval. According to the practical application requirements in the open sea, unattended acoustic conditioning equipment was developed. The ranching equipment was used in 12 m × 12 m × 2.5 m cages, and the behavior of black seabream juveniles was successfully guided after 7 days. Of the 16000 released fish, 82.5% of them were conditioned with a flexible grading net. To avoid inducing a stress response, the juveniles were released into the sea ranch in situ from the net cage. The acoustic conditioning equipments were moved into the open sea and the aggregation phenomenon of the released fish was observed when the sound was played. After 6 months of investigation and based on Sr+ marking, only one acoustically conditioned fish was found outside the 3.5-km2 sea ranch area, thereby reached the goal of guiding activity. The practical effect in the Xiangshan Bay sea ranch showed the validity of the acoustic conditioning system, which may contribute to improve the operation of the sea ranches in the East China Sea. [ABSTRACT FROM AUTHOR]- Published
- 2018
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5. The Roles of Heat Shock Proteins 70 and 90 in <italic>Exopalaemon carinicauda</italic> After WSSV and <italic>Vibrio anguillarum</italic> Challenges.
- Author
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Li, Jitao, Li, Jian, Duan, Yafei, Chen, Ping, and Liu, Ping
- Abstract
Heat shock proteins (HSPs), such as HSP70 and HSP90, are a suite of highly conserved proteins produced in all cellular organisms when they are exposed to stresses. In aquatic animals, they have been proved to play important roles in response to environmental pollutants and particularly in the non-specific immune responses to pathogen infections. In the present study, the expression profiles of HSP70 and HSP90 genes in hemocytes and hepatopancreas from the ridgetail white prawn
Exopalaemon carinicauda infected with WSSV andVibrio anguillarum were detected using reverse transcription polymerase chain reaction (RT-PCR). After WSSV challenge, the expression level of HSP 70 gene transcripts in the hemocytes and hepatopancreas increased to peak level at 6 h and 48 h, respectively. HSP90 gene transcripts in hemocytes and hepatopancreas were up-regulated significantly at 12 h and 6 h, respectively. DuringV. anguillarum challenge, the mRNA content of HSP70 gene in hemocytes and hepatopancreas increased significantly at 12 h and 6 h post-infection, respectively. The expression level of HSP90 gene both in hemocytes and hepatopancreas were up-regulated in the first 3 h. The expression patterns of HSP70 and HSP90 genes in hemocytes and hepatopancreas showed temporal and spatial differences after challenged with WSSV andV. anguillarum . The results suggested that HSPs might be involved in immune responses to pathogens challenge inE. carinicauda . [ABSTRACT FROM AUTHOR]- Published
- 2018
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6. Stress-induced systems in Escherichia coli and their response to terahertz radiation.
- Author
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Peltek, S., Demidova, E., Popik, V., and Goryachkovskaya, T.
- Abstract
We summarize the latest data concerning the reactions of Escherichia coli to nonthermal terahertz radiation. Escherichia coli is the simplest and most convenient model object for studying the effects of terahertz radiation on living organisms. Its genetics and metabolism have been well studied, and its easy accessibity to genetic engineering allows designing biosensors that employ the promoters of genes activated by certain stress factors and the reporter GFP protein. Escherichia coli cells transformed with such biosensor constructs produce easily quantitatable fluorescence in response to terahertz radiation. In this review, we present data on the reaction of certain E. сoli stress-induced systems to terahertz radiation, both ours and reported by other authors. We discuss experimental results for E. сoli/pKatGGFP, E. сoli/pCopAGFP, and E. сoli/pEmrRGFP biosensors, which are used to identify E. сoli genetic networks responding to oxidative stress, copper ion homeostasis failures, and antiseptics, respectively. The data reviewed indicate that exposure to nonthermal terahertz radiation activates E. сoli gene networks related to oxidative stress and copper ion homeostasis but does not affect those induced by antibiotics, protonophores, or superoxide anions. The fact that E. сoli/pKatGGFP and E. сoli/pCopAGFP biosensors have different activation and reaction periods when exposed to terahertz radiation and natural inducers suggests that the responses of oxidative stress and copper ion homeostasis systems to terahertz radiation are specific. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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7. Protein degradation in the skeletal muscles of parrs and smolts of the Atlantic salmon Salmo salar L.
- Author
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Kantserova, N., Lysenko, L., and Nemova, N.
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PROTEOLYSIS ,ATLANTIC salmon ,SKELETAL muscle ,SMOLTING ,PROTEOLYTIC enzymes ,PHYSIOLOGY - Abstract
This paper reports a study of the activity of calcium-dependent proteases (calpains) and proteasome in the skeletal muscles of parrs and smolts of the Atlantic salmon Salmo salar L. from the Indera River (the Kola Peninsula). It was demonstrated that the growth rate and protein mass accumulation during smoltification in salmonid fishes are inversely related to the activity of proteases in their muscles. It was noted that decreased protein degradation in the skeletal muscles of salmon juveniles serves as a mechanism ensuring the intensive growth and physiological maturity necessary for migration from the river to the sea. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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8. BackMatter.
- Author
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Kupervasser, Oleg
- Published
- 2015
9. Degradation of skeletal muscle protein during growth and development of salmonid fish.
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Nemova, N., Lysenko, L., and Kantserova, N.
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PROTEOLYSIS ,SALMONIDAE ,FISH growth ,FISH development ,MUSCLE proteins - Abstract
Published data and the results of the authors' own studies on the role of intracellular proteolytic enzymes and the metabolic and signaling processes regulated by these enzymes at certain stages of growth and development of salmonid fishes are analyzed in the present review. The major pathways of intracellular proteolysis relying on autophagy, proteasome activity, and calpain activity are considered, as well as the relative contribution of these pathways to proteolysis in skeletal muscle of the fish. Skeletal muscle accounts for more than half of the weight of the fish and undergoes the most significant changes due to the action of anabolic and catabolic signals. Special attention is paid to the intensity of protein degradation during the active growth period characterized by a high rate of protein synthesis and metabolism in fish, as well as to protein degradation during the reproductive period characterized by predomination of catabolic processes in contrast to the growth period. Skeletal muscle plays a unique role as a source of plastic and energy substrates in fish, and, therefore, the process of muscle protein degradation is regarded as a key mechanism for the regulation of growth intensity in juvenile salmon and for maintenance of viability and reproductive capacity of salmonid fish during the maturation of gametes, starvation, and migration related to spawning. The possibility of using a set of parameters of intracellular proteolysis to characterize the early development of salmonids is demonstrated in the review. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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10. Effects of heat stress on serum cortisol, alkaline phosphatase activity and heat shock protein 40 and 90β mRNA expression in rainbow trout Oncorhynchus mykiss.
- Author
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Zhen LI, Zhe LIU, Yan Ni WANG, Yu Jun KANG, Jian Fu WANG, Hai Na SHI, Jin Qiang HUANG, and Li JIANG
- Published
- 2016
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11. Interaction of temperature and salinity on the expression of immunity factors in different tissues of juvenile turbot Scophthalmus maximus based on response surface methodology.
- Author
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Huang, Zhihui, Ma, Aijun, Wang, Xin'an, Lei, Jilin, Li, Weiye, Wang, Ting, Yang, Zhi, and Qu, Jiangbo
- Subjects
PSETTA maxima ,RESPONSE surfaces (Statistics) ,SALINITY ,GENE expression ,IMMUNOGLOBULIN M - Abstract
Central Composite Design (CCD) and response surface methodology were used in the experiment to examine the combined effect of temperature (16-28°C) and salinity (18-42) on Hsp70 and IgM genes expression levels in turbot ( Scophthalmus maximus) liver and kidney. The results showed that the coefficients of determination ( R =0.965 2 for liver Hsp70, 0.972 9 for kidney Hsp70, 0.921 for liver IgM and 0.962 1 for kidney IgM) and probability values ( P<0.01) were significant for the regression model. The interactive effect between temperature and salinity on liver Hsp70, kidney Hsp70 and liver IgM were not significant ( P>0.05), while the interactive effect between temperature and salinity on kidney IgM was significant ( P<0.01). The model equation could be used in practice for forecasting Hsp70 and IgM genes expression levels in the liver and kidney of juvenile turbot via applying statistical optimization of the response of interest, at which the maximum liver Hsp70, kidney Hsp70, liver IgM and kidney IgM of 1.48, 1.49, 2.48, and 1.38, respectively, were reached. The present model may be valuable in assessing the feasibility of turbot farming at different geographic locations and, furthermore, could be a useful reference for scientists studying the immunity of turbot. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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12. Dynamic flame surface density modelling of flame deflagration in vented explosion.
- Author
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Gubba, S., Ibrahim, S., and Malalasekera, W.
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FLAME ,DENSITY ,SURFACE chemistry ,LARGE eddy simulation models ,TURBULENCE ,COMPARATIVE studies ,CHEMISTRY experiments - Abstract
The propagation of transient, turbulent premixed flames in a vented explosion chamber in the presence of a series of obstacles is numerically investigated by a dynamic formulation for the Flame Surface Density (FSD) with the Large Eddy Simulations (LES) technique. The chemistry is modelled by a one-step overall reaction, which simulates the reaction of a stoichiometric propane-air mixture. The FSD modelling in the reaction rate model is numerically employed with two different sub-grid scale (SGS) models. The first one is based on an empirical correlation of the SGS velocity fluctuations and the second one is based on similarity ideas involved in solving the wrinkled flame front considered as a fractal surface. The numerical predictions are analyzed and compared against an algebraic, simple FSD model together with experimental data. The calculations show that the dynamic FSD models provide superior results as compared with the algebraic FSD model. The comparisons demonstrate the importance of the contributions from the unresolved FSD and provide good agreement with experimental data for the flame structure, overpressure, and burning velocities. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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13. Palaeolimnological evidence of environmental change over the last 400 years in the Rwenzori Mountains of Uganda.
- Author
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McGlynn, Gayle, Mackay, Anson W., Rose, Neil L., Taylor, Richard G., Leng, Melanie J., and Engstrom, Daniel R.
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CLIMATE change ,GLOBAL environmental change ,LIMNOLOGY ,DIATOMS ,CARBON - Abstract
Tropical alpine areas may be highly sensitive to climate change. Yet, because high-resolution palaeoenvironmental studies in these regions are scant, patterns of environmental change over the last few centuries, and linkages with regional changes, remain poorly resolved. This article presents a 400-year palaeolimnological record from Lower Kitandara Lake (3,989 m above m.a.s.l.), located in the Rwenzori Mountains of Uganda, where marked glacial recession has been recorded over much of the twentieth century. An age model is produced for a 57.5 cm sediment core based on
210 Pb and14 C dating, suggesting a basal date of approximately 1600 AD. Diatom and organic geochemistry (%TOC, C/N ratios, δ13 C) analyses are carried out at an approximately decadal resolution. Twentieth-century glacial recession does not appear to have significantly impacted either the diatom or geochemical records. However, large ecological changes have occurred during the past 400 years, particularly shown by the diatom fluxes and geochemical data. Throughout the core, the diatom record reveals only minor changes in assemblage composition, which may be related to the dominance of Staurosira construens var. venter in the lake’s diatom flora, a tychoplanktonic taxon which is highly adaptive to environmental change. Geochemical analyses, however, reveal a marked change at around the end of the eighteenth century, when C/N ratios suggest an increase in the dominance of algal aquatic sources to lacustrine organic matter, concomitant with a stabilisation of catchment inputs and increased diatom productivity, which may have been caused by reduced glacial inputs. The relationship between these changes at Lower Kitandara Lake and wider regional climate change that occurred at the end of the eighteenth century is not well understood, but this study highlights the need for additional research to link drivers of alpine ecosystem change with those operating at low altitudes. [ABSTRACT FROM AUTHOR]- Published
- 2010
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14. Physical and chemical limnology of alpine lakes and pools in the Rwenzori Mountains (Uganda–DR Congo).
- Author
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Eggermont, Hilde, Russell, James, Schettler, Georg, Damme, Kay, Bessems, Ilse, and Verschuren, Dirk
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LIMNOLOGY ,MOUNTAIN ecology ,LAKES - Abstract
This study describes the physical and chemical properties of 17 Afroalpine lakes (>2 m deep) and 11 pools (<2 m deep) in the Rwenzori mountains, Uganda-DR Congo, with the aim to establish the baseline conditions against which to evaluate future environmental and biological changes in these unique tropical ecosystems, and to provide the foundation for lake-based paleoenvironmental studies. Most Rwenzori lakes are located above 3,500 m elevation, and dilute (5–52 μS/cm specific conductance at 25°C) open systems with surface in- and outflow. Multivariate ordination and pairwise correlations between environmental variables mainly differentiate between (1) lakes located near or above 4,000 m (3,890–4,487 m), with at least some direct input of glacial meltwater and surrounded by rocky catchments or alpine vegetation; and (2) lakes located mostly below 4,000 m (2,990–4,054 m), remote from glaciers and surrounded by Ericaceous vegetation and/or bogs. The former group are mildly acidic to neutral clear-water lakes (surface pH: 5.80–7.82; Secchi depth: 120–280 cm) with often above-average dissolved ion concentrations (18–52 μS/cm). These lakes are (ultra-) oligotrophic to mesotrophic (TP: 3.1–12.4 μg/l; Chl- a: 0.3–10.9 μg/l) and phosphorus-limited (mass TN/TP: 22.9–81.4). The latter group are mildly to strongly acidic (pH: 4.30–6.69) waters stained by dissolved organic carbon (DOC: 6.8–13.6 mg/l) and more modest transparency (Secchi-disk depth: 60–132 cm). Ratios of particulate carbon, particulate nitrogen and chlorophyll a in these lakes indicate that organic matter in suspension is primarily derived from the lakes’ catchments rather than aquatic primary productivity. Since key features in the Rwenzori lakes’ abiotic environment are strongly tied to temperature and catchment hydrology, these Afroalpine lake ecosystems can be expected to respond sensitively to climate change and glacier melting. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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15. Diversity in the olfactory epithelium of bony fishes: Development, lamellar arrangement, sensory neuron cell types and transduction components.
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Anne Hansen and Barbara Zielinski
- Abstract
In this study we use a taxon-based approach to examine previous, as well as new findings on several topics pertaining to the peripheral olfactory components in teleost fishes. These topics comprise (1) the gross anatomy of the peripheral olfactory organ, including olfactory sensory neuron subtypes and their functional parameters, (2) the ultrastructure of the olfactory epithelium, and (3) recent findings regarding the development of the nasal cavity and the olfactory epithelium. The teleosts are living ray-finned fish, and include descendants of early-diverging orders (e.g., salmon), specialized descendants (e.g., goldfish and zebrafish), as well as the Acanthopterygii, numerous species with sharp bony rays, including perch, stickleback, bass and tuna. Our survey reveals that the olfactory epithelium lines a multi-lamellar olfactory rosette in many teleosts. In Acanthopterygii, there are also examples of flat, single, double or triple folded olfactory epithelia. Diverse species ventilate the olfactory chamber with a single accessory nasal sac, whereas the presence of two sacs is confined to species within the Acanthopterygii. Recent studies in salmonids and cyprinids have shown that both ciliated olfactory sensory neurons (OSNs) and microvillous OSNs respond to amino acid odorants. Bile acids stimulate ciliated OSNs, and nucleotides activate microvillous OSNs. G-protein coupled odorant receptor molecules (OR-, V1R-, and V2R-types) have been identified in several teleost species. Ciliated OSNs express the G-protein subunit G
αolf/s , which activates cyclic AMP during transduction. Localization of G protein subunits Gα0 and Gαq/11 to microvillous or crypt OSNs, varies among different species. All teleost species appear to have microvillous and ciliated OSNs. The recently discovered crypt OSN is likewise found broadly. There is surprising diversity during ontogeny. In some species, OSNs and supporting cells derive from placodal cells; in others, supporting cells develop from epithelial (skin) cells. In some, epithelial cells covering the developing olfactory epithelium degenerate, in others, these retract. Likewise, there are different mechanisms for nostril formation. We conclude that there is considerable diversity in gross anatomy and development of the peripheral olfactory organ in teleosts, yet conservation of olfactory sensory neuron morphology. There is not sufficient information to draw conclusions regarding the diversity of teleost olfactory receptors or transduction cascades. [ABSTRACT FROM AUTHOR]- Published
- 2005
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16. Flames with Realistic Thermal Expansion in a Time-Dependent Turbulent Flow.
- Author
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Akkerman, V. B. and Bychkov, V. V.
- Subjects
FLAME ,COMBUSTION ,THERMAL expansion ,TURBULENCE ,FLUID dynamics ,HYPOTHESIS - Abstract
The propagation velocity of turbulent premixed flames with real thermal expansion in a time-dependent external flow is studied for an infinitely thin flame front and for flames of small but finite thickness. It is shown that the influence of temporal pulsations is usually small and can be neglected for reasonable values of the pulsation frequency. The role of pulsations is even smaller for realistic thermal expansion in comparison with the artificial case of zero thermal expansion studied previously. The results obtained indicate that the Taylor hypothesis of “ stationary” turbulence is a good approximation for turbulent flames. The role of pulsations is substantial only if the integral turbulent length scale is close to the cut-off wavelength of the Darrieus-Landau instability. In this particular case, temporal pulsations can be important for explaining recent experiments on turbulent burning. [ABSTRACT FROM AUTHOR]
- Published
- 2005
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17. Morituri te salutant? Olfactory signal transduction and the role of phosphoinositides.
- Author
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Rebecca Elsaesser and Jacques Paysan
- Abstract
During the past 150 years, researchers have investigated the cellular, physiological, and molecular mechanisms underlying the sense of smell. Based on these efforts, a conclusive model of olfactory signal transduction in the vertebrate's nose is now available, spanning from G-protein-mediated odorant receptors to ion channels, which are linked by a cyclic adenosine 3',5'-monophosphate-mediated signal transduction cascade. Here we review some historical milestones in the chronology of olfactory research, particularly emphasising the role of cyclic nucleotides and inositol trisphosphate as alternative second messengers in olfactory cells. We will describe the functional anatomy of the nose, outline the cellular composition of the olfactory epithelium, and describe the discovery of the molecular backbone of the olfactory signal transduction cascade. We then summarize our current model, in which cyclic adenosine monophosphate is the sole excitatory second messenger in olfactory sensory neurons. Finally, a possible significance of microvillous olfactory epithelial cells and inositol trisphosphate in olfaction will be discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2005
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18. Modeling and Large Eddy Simulation of Deflagration Dynamics in a Closed Vessel.
- Author
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Makarov, D. V. and Molkov, V. V.
- Subjects
EDDIES ,COMBUSTION ,TURBULENCE ,SIMULATION methods & models ,FLAME ,HYDROGEN - Abstract
The paper describes a large eddy simulation model of gaseous deflagration in a closed vessel and simulation results for stoichiometric hydrogen-air premixed combustion initiated at the center of a closed 6.37-m³ spherical vessel. The model is based on the large eddy simulation approach to turbulence modeling and the gradient method to model the mass burning rate in premixed combustion. The method for simulated flame-front thickness reduction is suggested, and its performance is investigated. The solution-adaptive mesh refinement is used to decrease the CPU time required for simulation. The simulated deflagration-pressure dynamics is in agreement with published experimental data, and the flame-front velocity is in agreement with simulation results obtained according to the lumped parameter model for the same experiment. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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19. Activation of the Escherichia coli SoxRS-Regulon by Nitric Oxide and Its Physiological Donors.
- Author
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Vasil'eva, S., Stupakova, M., Lobysheva, I., Mikoyan, V., and Vanin, A.
- Abstract
Activation of the Escherichia coli SoxRS-regulon by nitric oxide (NO) and its physiological donors (S-nitrosothiol (GS-NO) and dinitrosyl iron complexes with glutathione (DNIC
glu ) and cysteine (DNICcys ) ligands) has been studied. To elucidate the molecular mechanisms of signal transduction via nitrosylation of Fe-S-centers in SoxR, the ability of pure NO and NO-producing agents to activate the SoxRS-regulon in E. coli cells bearing a soxS:: lacZ operon (promoter) fusion has been compared. EPR spectroscopy of whole cells has been used to monitor the formation of inducible protein–DNIC complexes. DNICcys , GS-NO, and pure NO appeared to be potent inducers of soxS expression, whereas DNICglu was considerably less efficient. Thus, lower in vitro stability of DNICcys was in contrast with its higher biological activity. Pretreatment of the cells with o-phenanthroline, a chelating agent for iron, prevented soxS expression by GS-NO. Treatment of intact E. coli cells with DNIC, GS-NO, and NO at equimolar concentration 150 μM resulted in formation of a single EPR-detectable DNIC-type signal with g = 2.03. The initial stage in the SoxR transcription activity is supposed to include two steps: first, DNIC primers are formed from exogenous NO and free iron, and then these DNIC disintegrate SoxR [2Fe-2S] clusters and thus activate SoxRS-regulon transcription. [ABSTRACT FROM AUTHOR]- Published
- 2001
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20. Oxidative Stress and Mechanisms of Protection Against It in Bacteria.
- Author
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Lushchak, V.
- Abstract
In the review contemporary data on the effects of oxidative stresses of various kinds in bacteria are summarized. A general theory of oxidative stress, peculiarities of oxidative stress in eukaryotes and prokaryotes, and natural and induced oxidative stresses are described. Data on the mechanisms of protection against oxidative stress are given, including prevention of the generation of oxidative stress, prevention of propagation of free radical chain reactions, and the mechanisms of repair of damaged DNA. The regulation of effector genes via redox-sensitive iron-containing proteins is analyzed. Special attention is given to the expression of so-called antioxidant and associated enzymes as protection mechanisms and to the space–time organization of the response of bacteria to oxidative stress. [ABSTRACT FROM AUTHOR]
- Published
- 2001
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21. Chemoelectrical signal transduction in olfactory sensory neurons of air-breathing vertebrates.
- Author
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Frings, S.
- Subjects
SMELL ,CHEMICAL senses ,PHYSIOLOGY ,CELLULAR signal transduction ,CELL receptors ,CHLORIDE channels - Abstract
When odorants bind to the sensory cilia of olfactory sensory neurons, the cells respond with an electrical output signal, typically a short train of action potentials. This review describes the present state of knowledge about the olfactory signal transduction process. In the last decade, a set of transduction molecules has been identified which help to explain many aspects of the sensory response. Odor-induced second-messenger production, activation of transduction channels, the central role of the ciliary Ca
2+ concentration, as well as mechanisms that mediate adaptation, are all qualitatively understood on the basis of a consistent scheme for chemoelectrical transduction. This scheme, although necessarily incomplete, can serve as a working model for further experimentation which may reveal kinetical aspects of signal transduction processes in olfactory sensory neurons. [ABSTRACT FROM AUTHOR]- Published
- 2001
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22. Crystal structure of the transcription activator BmrR bound to DNA and a drug.
- Author
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Heldwin, Ekaterina E. Zheleznova and Brennan, Richard G.
- Subjects
MULTIDRUG resistance ,BACTERIA ,DRUG resistance in microorganisms ,CELLULAR mechanics - Abstract
Reports on the structure of multidrug transporter in Bacillus subtilis in complex with the drug tetraphenylphosphonium and a 22-base-pair oligodeoxynucleotide encompassing the promoter. The efflux chemically diverse drugs by multidrug transporters, which is one mechanism of multidrug resistance in bacteria; How the structure reveals an unexpected mechanism for transcription activation.
- Published
- 2001
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23. Effects of dietary carnitine and lipid on growth and body composition of hybrid striped bass (Morone chrysops ♀× M. saxatilis ♂).
- Author
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Gaylord, T.G. and Gatlin, D.M.
- Abstract
A study was undertaken to investigate the effects of graded dietary levels and different types of carnitine on hybrid striped bass ( Morone chrysops ♀ × M. saxatilis ♂ %) fed different levels of lipid. An incomplete factorial design was utilized in which diets containing lipid at either 5 or 10% were supplemented with l-carnitine at 0, 500, or 1000 mg kg
−1 diet, dl-carnitine at 1000 mg kg−1 diet, or carnitine chloride to provide 1000 mg carnitine kg−1 diet. Juvenile hybrid striped bass (3.3 g fish−1 ) were stocked into individual 38-l aquaria connected as a brackish water (6‰), recirculating system and fed each diet in triplicate for 9 weeks. Supplementation of the diet with 1000 mg carnitine kg−1 increased muscle carnitine from 35.5 to 47.7 μg g−1 tissue. Carnitine supplementation did not result in increased weight gain regardless of carnitine level or type; however, weight gain showed a significant ( p<0.05) response to dietary lipid with fish fed diets containing 10% lipid growing 34% more than fish fed diets with 5% lipid. The hepatosomatic index also was unaffected by diet, but the intraperitoneal fat (IPF) ratio was significantly elevated (5.1 vs 3.2%) in fish fed diets with 10% lipid compared to those fed diets with 5% lipid. Fish fed diets containing 1000 mg carnitine kg−1 had increased IPF ratio values at 4.7% compared to 3.9% for fish fed the basal diet. Liver lipid also was responsive to dietary treatment, increasing from 6.7 to 8.8% of wet weight as dietary lipid increased from 5 to 10%. The relative quantities of triglycerides, free fatty acids and phospholipids in muscle and liver were not influenced by carnitine level, carnitine type or dietary lipid level. Supplementation of carnitine does not appear to be beneficial to hybrid striped bass based on either growth performance or body composition. [ABSTRACT FROM AUTHOR]- Published
- 2000
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24. Systemic regulation of L-carnitine in nutritional metabolism in zebrafish, Danio rerio.
- Author
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Li, Jia-Min, Li, Ling-Yu, Qin, Xun, Ning, Li-Jun, Lu, Dong-Liang, Li, Dong-Liang, Zhang, Mei-Ling, Wang, Xin, and Du, Zhen-Yu
- Abstract
Excess fat accumulation has been observed widely in farmed fish; therefore, efficient lipid-lowering factors have obtained high attention in the current fish nutrition studies. Dietary L-carnitine can increase fatty acid β-oxidation in mammals, but has produced contradictory results in different fish species. To date, the mechanisms of metabolic regulation of L-carnitine in fish have not been fully determined. The present study used zebrafish to investigate the systemic regulation of nutrient metabolism by dietary L-carnitine supplementation. L-carnitine significantly decreased the lipid content in liver and muscle, accompanied by increased concentrations of total and free carnitine in tissues. Meanwhile, L-carnitine enhanced mitochondrial β-oxidation activities and the expression of carnitine palmitoyltransferase 1 mRNA significantly, whereas it depressed the mRNA expression of adipogenesis-related genes. In addition, L-carnitine caused higher glycogen deposition in the fasting state, and increased and decreased the mRNA expressions of gluconeogenesis-related and glycolysis-related genes, respectively. L-carnitine also increased the hepatic expression of mTOR in the feeding state. Taken together, dietary L-carnitine supplementation decreased lipid deposition by increasing mitochondrial fatty acid β-oxidation, and is likely to promote protein synthesis. However, the L-carnitine-enhanced lipid catabolism would cause a decrease in glucose utilization. Therefore, L-carnitine has comprehensive effects on nutrient metabolism in fish. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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