Search results for "Fish"
showing 10 items of 3164 documents
On the relevance of genotoxicity for fish populations II: genotoxic effects in zebrafish (Danio rerio) exposed to 4-nitroquinoline-1-oxide in a compl…
2003
In order to characterize the impact of genotoxic potentials on populations of aquatic organisms in surface waters, zebrafish (Danio rerio) were exposed to the model genotoxicant 4-nitroquinoline-1-oxide (NQO) in a complete life-cycle test. Fish exposed to mean NQO concentrations of 0, 0.1, 0.3, 1.1, and 2.9 microg/l were examined by several genotoxicity assays with different endpoints. Assays included the unscheduled DNA synthesis (UDS) test, the comet assay, the alkaline filter elution, and the micronucleus test. The genotoxicity assays revealed an increasing genotoxicity, ranging from induction of DNA repair (even at the lowest concentration tested) to primary and secondary DNA alteration…
Genotoxicity of the fungicide dichlofluanid in seven assays
1991
Seven different endpoints for detection of genotoxicity have been used to demonstrate the DNA-altering properties of Dichlofluanid, a fungicide commonly used in viticulture pest control. Each endpoint (DNA synthesis inhibition test, alkaline viscosimetry, umu-test, alkaline filter elution, FADU-test, 32P-postlabeling, and electron microscopy) shows clear evidence of genotoxicity. These data indicate that application of the fungicide dichlofluanid may be mutagenic and/or carcinogenic for exposed humans.
Editorial: Zebrafish Epigenetics.
2022
A key area of focus in the field of epigenetics pertains the comprehension of the functional relevance of the epigenetic mechanisms occurring during embryogenesis to shape normal developmental trajectories and adult phenotypes (Atlasi and Stunnenberg, 2017; Skvortsova et al., 2018; Cavalieri, 2021; Marchione et al., 2021). Several lines of evidence highlighted that the small freshwater cyprinid Danio rerio, commonly known as zebrafish, is an excellent vertebrate model for research purposes in the field of epigenetics (Huang et al., 2013; Balasubramanian et al., 2019; Horsfield, 2019; Cavalieri, 2020). The general strengths of zebrafish over concurrent models are well known: ease of husbandr…
Top consumer abundance influences lake methane efflux
2015
Lakes are important habitats for biogeochemical cycling of carbon. The organization and structure of aquatic communities influences the biogeochemical interactions between lakes and the atmosphere. Understanding how trophic structure regulates ecosystem functions and influences greenhouse gas efflux from lakes is critical to understanding global carbon cycling and climate change. With a whole-lake experiment in which a previously fishless lake was divided into two treatment basins where fish abundance was manipulated, we show how a trophic cascade from fish to microbes affects methane efflux to the atmosphere. Here, fish exert high grazing pressure and remove nearly all zooplankton. This re…
An MLSA approach for the taxonomic update of the Splendidus clade, a lineage containing several fish and shellfish pathogenic Vibrio spp.
2016
A multilocus sequence analysis was undertaken in order to redefine the Splendidus clade of the genus Vibrio, a large group of species containing several pathogenic members that affect fish and shellfish, and are difficult to identify through both phenotypic and genotypic approaches. The study included analysis of partial sequences of recA, gyrB, mreB, rpoD and pyrH genes, as well as the 16S rRNA gene. Seventeen type strain species were included that were complemented with other reference strains and a collection of isolates tentatively identified as members of this clade, as well as a set of other Vibrio species. The clade was well defined and stable in all analyses, and was confirmed to co…
Investigating bacterial populations in styrene-degrading biofilters by 16S rDNA tag pyrosequencing
2014
Microbial biofilms are essential components in the elimination of pollutants within biofilters, yet still little is known regarding the complex relationships between microbial community structure and biodegradation function within these engineered ecosystems. To further explore this relationship, 16S rDNA tag pyrosequencing was applied to samples taken at four time points from a styrene-degrading biofilter undergoing variable operating conditions. Changes in microbial structure were observed between different stages of biofilter operation, and the level of styrene concentration was revealed to be a critical factor affecting these changes. Bacterial genera Azoarcus and Pseudomonas were among…
Long-term effects of crop management on Rhizobium leguminosarum biovar viciae populations.
2004
Little is known about factors that affect the indigenous populations of rhizobia in soils. We compared the abundance, diversity and genetic structure of Rhizobium leguminosarum biovar viciae populations in soils under different crop managements, i.e., wheat and maize monocultures, crop rotation, and permanent grassland. Rhizobial populations were sampled from nodules of pea- or vetch plants grown in soils collected at three geographically distant sites in France, each site comprising a plot under long-term maize monoculture. Molecular characterization of isolates was performed by PCR-restriction fragment length polymorphism of 16S-23S rDNA intergenic spacer as a neutral marker of the genomi…
Estimation of atrazine-degrading genetic potential and activity in three French agricultural soils
2004
The impact of organic amendment (sewage sludge or waste water) used to fertilize agricultural soils was estimated on the atrazine-degrading activity, the atrazine-degrading genetic potential and the bacterial community structure of soils continuously cropped with corn. Long-term application of organic amendment did not modify atrazine-mineralizing activity, which was found to essentially depend on the soil type. It also did not modify atrazine-degrading genetic potential estimated by quantitative PCR targeting atzA, B and C genes, which was shown to depend on soil type. The structure of soil bacterial community determined by RISA fingerprinting was significantly affected by organic amendmen…
Virulence and Molecular Typing of Vibrio harveyi Strains Isolated from Cultured Dentex, Gilthead Sea Bream and European Sea Bass
2003
Vibrio harveyi was isolated from internal organs or ulcers of diseased and apparently healthy gilthead sea bream (Sparus aurata) and European sea bass (Dicentrarchus labrax) cultured in several fish farms located on the Spanish Mediterranean coast. The prevalence of the bacterium was significantly higher in European sea bass than in gilthead sea bream, and was closely related to the season in both fish species, occurring almost exclusively on warm months (June to November). After phenotypic characterization, a selection of forty five isolates from gilthead sea bream, sea bass, and several isolates previously obtained from common dentex (Dentex dentex) of the same area, were molecularly type…
Aeromonas hydrophila subsp. dhakensis isolated from feces, water and fish in Mediterranean Spain.
2012
Eight Aeromonas hydrophila-like arabinose-negative isolates from diverse sources (i.e., river freshwater, cooling-system water pond, diseased wild European eels, and human stools) sampled in Valencia (Spain) during 2004-2005, were characterized by 16S rRNA gene sequencing and extensive biochemical testing along with reference strains of most Aeromonas species. These isolates and all reference strains of A. hydrophila subsp. dhakensis and A. aquariorum showed a 16S rRNA sequence similarity of 99.8-100%, and they all shared an identical phenotype. This matched exactly with that of A. hydrophila subsp. dhakensis since all strains displayed positive responses to the Voges-Prokauer test and to t…