Search results for "BIOTIC"
showing 10 items of 1505 documents
Metabolic detoxification: implications for thresholds.
2000
The fact that chemical carcinogenesis involves single, isolated, essentially irreversible molecular events as discrete steps, several of which must occur in a row to finally culminate in the development of a malignancy, rather suggests that an absolute threshold for chemical carcinogens may not exist. However, practical thresholds may exist due to saturable pathways involved in the metabolic processing, especially in the metabolic inactivation, of such compounds. An important example for such a pathway is the enzymatic hydrolysis of epoxides via epoxide hydrolases, a group of enzymes for which the catalytic mechanism has recently been established. These enzymes convert their substrates via…
Cadmium, Copper and Tributyltin effects on fertilization of Paracentrotus lividus (Echinodermata)
2009
Marine environments are continuously being threatened by a large number of xenobi- otics from anthropogenic sources. The effect of chemical pollution on living organisms are numerous and may impair reproductive success of adults species of marine invertebrate and vertebrate through effects on gamete quality. Echinoderms are characterized by external fertilizzation and gametes, free of any type of protection, may be in contact with toxic substances so the reproductive success depends largely on the environment conditions. The purpose of this work is to assess the effects on the in vitro fertiliza- tion of exposure of sea urchin Paracentrotus lividus gametes to xenobiotic substances as CuSO4,…
A One Health perspective on the issue of the antibiotic resistance
2020
For a few years now, the One Health concept has appeared to go hand in hand with the issue of antibiotic resistance as the most comprehensive and global solution. As part of a study comparing the publicization process of the links between antibiotic resistance and food in France and in the United States, this paper retraces the One Health concept's trajectory in terms of significations and (re)definitions, according to the actors adopting this approach as a viable solution. Furthermore, this paper questions the concept's take over impact in antibiotic resistance reframing as well as its expansion in terms of functioning and applicability. Within social sciences research, interest in the iss…
Influence of land-use intensity on the spatial distribution of N-cycling microorganisms in grassland soils
2011
A geostatistical approach using replicated grassland sites (10 m × 10 m) was applied to investigate the influence of grassland management, i.e. unfertilized pastures and fertilized mown meadows representing low and high land-use intensity (LUI), on soil biogeochemical properties and spatial distributions of ammonia-oxidizing and denitrifying microorganisms in soil. Spatial autocorrelations of the different N-cycling communities ranged between 1.4 and 7.6 m for ammonia oxidizers and from 0.3 m for nosZ-type denitrifiers to scales >14 m for nirK-type denitrifiers. The spatial heterogeneity of ammonia oxidizers and nirS-type denitrifiers increased in high LUI, but decreased for biogeochemical …
The effect of a temperature-sensitive prophage on the evolution of virulence in an opportunistic bacterial pathogen
2019
AbstractViruses are key actors of ecosystems and have major impacts on global biogeochemical cycles. Prophages deserve particular attention as they are ubiquitous in bacterial genomes and can enter a lytic cycle when triggered by environmental conditions. We explored how temperature affects the interactions between prophages and other biological levels by using an opportunistic pathogen, the bacterium Serratia marcescens, that harbours several prophages and that had undergone an evolution experiment under several temperature regimes. We found that the release of one of the prophages was temperature-sensitive and malleable to evolutionary changes. We further discovered that the virulence of …
Prevalence of genetically similarFlavobacterium columnarephages across aquaculture environments reveals a strong potential for pathogen control
2020
SummaryIntensive aquaculture conditions expose fish to bacterial infections, leading to significant financial losses, extensive antibiotic use and risk of antibiotic resistance in target bacteria.Flavobacterium columnarecauses columnaris disease in aquaculture worldwide. To develop a bacteriophage-based control of columnaris disease, we isolated and characterized 126F. columnarestrains and 63 phages againstF. columnarefrom Finland and Sweden. Bacterial isolates were virulent on rainbow trout (Oncorhynchus mykiss) and fell into four previously described genetic groups A, C, E and G, with genetic groups C and E being the most virulent. Phage host range studied against a collection of 228 bact…
Co-Loading of Ascorbic Acid and Tocopherol in Eudragit-Nutriosomes to Counteract Intestinal Oxidative Stress
2019
The present study aimed at developing a new vesicular formulation capable of promoting the protective effect of ascorbic acid and tocopherol against intestinal oxidative stress damage, and their efficacy in intestinal wound healing upon oral administration. A pH-dependent copolymer (Eudragit®
Evolution and comparative genomics of di-symbiotic systems in aphids from the Lachninae subfamily and genome reduction in Serratia symbiotica
2016
Ph.D. thesis presented by Alejandro Manzano Marín Director: Prof. Dr. Amparo Latorre Castillo Institution: Universiat de València
Central nervous system involvement at first relapse in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and anthracycl…
2009
Background The prevalence of and risk factors for central nervous system recurrence in patients with acute promyelocytic leukemia are not well established and remain a controversial matter. Design and Methods Between 1996 and 2005, 739 patients with newly diagnosed acute promyelocytic leukemia enrolled in two consecutive trials (PETHEMA LPA96 and LPA99) received induction therapy-with all-trans retinoic acid and idarubicin. Consolidation therapy comprised three courses of anthracycline monochemotherapy (LPA96), with all-trans retinoic acid and reinforced doses of idarubicin in patients with an intermediate or high risk of relapse (LPA99). Central nervous system prophylaxis was not given. Re…
Perspectives for the Treatment of Brucellosis in the 21st Century: The Ioannina Recommendations
2007
Policy Forum. Competing interests: ER has received research grants from Daiichi, Bayer, and Theravance and has served as a consultant to Pfizer, Theravance, Bayer, Wyeth, Rosetta, and BiondVax. Summary Points Brucellosis remains the commonest anthropozoonosis worldwide, and its treatment remains complex, requiring protracted administration of more than one antibiotic. In November 2006, a consensus meeting aimed at reaching a common specialist statement on the treatment of brucellosis was held in Ioannina, Greece under the auspices of the International Society of Chemotherapy and the Institute of Continuing Medical Education of Ioannina. The author panel suggests that the optimal treatment o…