The Experts below are selected from a list of 1716 Experts worldwide ranked by ideXlab platform

Claudia Gérard - One of the best experts on this subject based on the ideXlab platform.

  • Consumption of toxic cyanobacteria by Potamopyrgus Antipodarum (Gastropoda, Prosobranchia) and consequences on life traits and microcystin accumulation
    Harmful Algae, 2008
    Co-Authors: Emilie Lance, Emilie Bugajny, Myriam Bormans, Claudia Gérard
    Abstract:

    Among the wide range of toxins produced by cyanobacterial blooms, microcystins (MCs) are the most common and are known to accumulate in aquatic organisms. Freshwater gastropods are grazers and likely to ingest toxic cyanobacteria, particularly Planktothrix agardhii, one of the most common species in the northern hemisphere. The study examines (i) the ingestion of toxic P. agardhii by the prosobranch Potamopyrgus Antipodarum, (ii) the kinetics of MC accumulation and depuration in snail tissues during and post-exposure, and (iii) the impact of MCs on their life traits (survival, growth and fecundity). We showed that P. Antipodarum ingested 71% of cyanobacteria available during the first 24 h in the presence or not of non-toxic food, and accumulated 1.3% of ingested MCs during the 5-week intoxication period. Elimination of MCs was total after 3 weeks of depuration. A decrease of growth and fecundity was observed during the intoxication period, but it was reversible after the end of exposure. Results are discussed in terms of variation of the response between prosobranch and pulmonate gastropods to toxic cyanobacteria exposure, and the negative impact of toxic cyanobacteria on natural communities of freshwater gastropods.

  • variation in the response of the invasive species Potamopyrgus Antipodarum smith to natural cyanobacterial toxin and anthropogenic herbicide atrazine stressors
    Environmental Pollution, 2005
    Co-Authors: Claudia Gérard, Virginie Poullain
    Abstract:

    In the context of increasing freshwater pollution, the impact on life-traits (survival, growth and fecundity) and locomotion of Potamopyrgus Antipodarum of a 5-week field-concentration exposure to the cyanobacterial toxin microcystin-LR and the triazine herbicide, atrazine was studied. Whatever the age of exposed snails (juveniles, subadults, adults), microcystin-LR induced a decrease in survival, growth and fecundity but had no effect on locomotion. Atrazine induced a decrease in locomotory activity but had no significant effect on the life-traits. These results are discussed in terms of consequences to field populations.

  • establishment of a new host parasite association between the introduced invasive species Potamopyrgus Antipodarum smith gastropoda and sanguinicola sp plehn trematoda in europe
    Journal of Zoology, 2003
    Co-Authors: Claudia Gérard, Joseph Le Lannic
    Abstract:

    The trematode fauna of Potamopyrgus Antipodarum , an introduced and invasive gastropod mollusc species native to New Zealand, was studied in Mont Saint Michel Bay (France). The study revealed, for the first time in Europe, the occurrence of larval digenean species, Sanguinicola sp., a blood fluke of fish never previously recorded in this prosobranch. Phase contrast and scanning electron microscopy was used to investigate the morphology of the parasite. Hypotheses on the origin of the P. Antipodarum–Sanguinicola sp. association are discussed in relation to the history of invasion of the gastropod into brackish and fresh waters and the structure of local gastropod communities.

  • Potamopyrgus Antipodarum (Mollusca:Hydrobiidae) in continental aquatic gastropod communities: impact of salinity and trematode parasitism
    Hydrobiologia, 2003
    Co-Authors: Claudia Gérard, Alexia Blanc, Katherine Costil
    Abstract:

    The structure of gastropod communities was examined from January to June 1999 in four sites of the streams of Mont Saint-Michel Bay along a gradient of salinity, and the occurrence of larval trematodes infecting snails was studied. Abundance and species richness of gastropods increased from polyhaline (95 snails, 1 species) to oligohaline waters (6672 snails, 6 species). Whatever the salinity, the most abundant species was Potamopyrgus Antipodarum, an invasive non-indigenous species that represented 80% of the gastropods. Only one male was found in P. Antipodarum populations suggesting a predominantly parthenogenetic mode of reproduction. Among 7218 gastropods collected, 1.2% were infected by larval trematodes: 5 species in Lymnaea peregra (4.4%), 4 species in Planorbis planorbis (12.0%), one echinostome in Physa acuta (0.2%), and a new species of Sanguinicola in P. Antipodarum (0.5%). This is the first record of infected P. Antipodarum in Europe. No parasites were found in polyhaline waters. The prevalence per host population varied from 0 to 100% depending on time of collection, salinity and host species. In the lowest-salinity site, abundance of gastropods and prevalence of trematodes were negatively correlated. The dominance of P. Antipodarum in the gastropod communities is discussed in relation with euryhalinity, parthenogenesis and weak rate of parasitism.

  • Establishment of a new host–parasite association between the introduced invasive species Potamopyrgus Antipodarum (Smith) (Gastropoda) and Sanguinicola sp. Plehn (Trematoda) in Europe
    Journal of Zoology, 2003
    Co-Authors: Claudia Gérard, Joseph Le Lannic
    Abstract:

    The trematode fauna of Potamopyrgus Antipodarum , an introduced and invasive gastropod mollusc species native to New Zealand, was studied in Mont Saint Michel Bay (France). The study revealed, for the first time in Europe, the occurrence of larval digenean species, Sanguinicola sp., a blood fluke of fish never previously recorded in this prosobranch. Phase contrast and scanning electron microscopy was used to investigate the morphology of the parasite. Hypotheses on the origin of the P. Antipodarum–Sanguinicola sp. association are discussed in relation to the history of invasion of the gastropod into brackish and fresh waters and the structure of local gastropod communities.

Joseph Le Lannic - One of the best experts on this subject based on the ideXlab platform.

Gary R. Carvalho - One of the best experts on this subject based on the ideXlab platform.

  • isolation and characterization of di and trinucleotide microsatellites in the freshwater snail Potamopyrgus Antipodarum
    Molecular Ecology Notes, 2001
    Co-Authors: David Weetman, Lorenz Hauser, Gary R. Carvalho
    Abstract:

    The freshwater prosobranch snail Potamopyrgus Antipodarum is an important model system for studying the maintenance of sexual reproduction in its native New Zealand. Since introduction to the UK in the 1850s, the species has spread throughout Europe and recently the USA. We present the first microsatellites for P. Antipodarum. Using two isolation protocols, which are qualitatively compared, we have developed PCR primers for three di- and four trinucleotide microsatellites. All loci proved to be polymorphic, when screened for variability in several UK populations. These markers should be of considerable utility in future population and ecological genetics studies of this species.

  • Isolation and characterization of di‐ and trinucleotide microsatellites in the freshwater snail Potamopyrgus Antipodarum
    Molecular Ecology Notes, 2001
    Co-Authors: David Weetman, Lorenz Hauser, Gary R. Carvalho
    Abstract:

    The freshwater prosobranch snail Potamopyrgus Antipodarum is an important model system for studying the maintenance of sexual reproduction in its native New Zealand. Since introduction to the UK in the 1850s, the species has spread throughout Europe and recently the USA. We present the first microsatellites for P. Antipodarum. Using two isolation protocols, which are qualitatively compared, we have developed PCR primers for three di- and four trinucleotide microsatellites. All loci proved to be polymorphic, when screened for variability in several UK populations. These markers should be of considerable utility in future population and ecological genetics studies of this species.

  • Clonal Structure of the Introduced Freshwater Snail Potamopyrgus Antipodarum (Prosobranchia: Hydrobiidae), as Revealed by DNA Fingerprinting
    Proceedings of the Royal Society of London. Series B: Biological Sciences, 1992
    Co-Authors: Lorenz Hauser, Gary R. Carvalho, Roger N. Hughes, Royston E. Carter
    Abstract:

    Multi-locus DNA fingerprints were obtained from individuals of the hydrobiid snail, Potamopyrgus Antipodarum (= P. jenkinsi), by using an RNA derivative (pSPT 18.15) of Jeffreys9s 33. 15 minisatellite core sequence. Whole-body homogenization of snails yielded 3.21 $\pm $ 0.09 $\mu $g DNA per individual, producing complex profiles comprising 12-22 fragments within the 1.0-20.0 kilobase (kb) size range. Fingerprints from natural and experimental populations identified three distinct clonal genotypes corresponding to morphological strains A, B and C, with only rare mutational variants. Mother-offspring comparisons of genetic fingerprints revealed genetic stability during apomictic parthenogenesis. Data support the notion that British populations of P. Antipodarum comprise three widespread obligate parthenogenetic clones resulting from a mid-19th Century introduction from Australasia. The present-day low levels of genotypic diversity are discussed in relation to the typical occurrence of P. Antipodarum in man-made or immature habitats.

Jörg Oehlmann - One of the best experts on this subject based on the ideXlab platform.

  • The antimicrobial agents triclocarban and triclosan as potent modulators of reproduction in Potamopyrgus Antipodarum (Mollusca: Hydrobiidae)
    Journal of Environmental Science and Health Part A, 2016
    Co-Authors: Cornelia Geiß, Katharina Ruppert, Tanja Heidelbach, Jörg Oehlmann
    Abstract:

    ABSTRACTIn this study, we assessed the chronic effects of the two antimicrobial substances triclocarban (TCC) and triclosan (TCS) on reproduction of a mollusk species by using the reproduction test with the New Zealand mudsnail Potamopyrgus Antipodarum. Snails coming from a laboratory culture were exposed for 28 days to nominal concentrations ranging from 0.1 up to 10 µg/L for both chemicals (measured 0.082–8.85 µg TCC/L; 0.068–6.26 µg TCS/L). At the end of the experiment, snails were dissected and embryos in the brood pouch were counted to assess the individualized reproductive success of adult snails. Exposure to TCC resulted in an inverted u-shaped concentration–response relationship, with a stimulation of reproduction at low concentrations followed by an inhibition at higher concentrations. The no observed effect concentration (NOEC) and the lowest observed effect concentration (LOEC) were 0.082 and 0.287 µg/L, respectively. TCS caused significantly increased embryo numbers at all tested concentration...

  • Comparative sensitivity of juvenile and adult Potamopyrgus Antipodarum (Mollusca: Hydrobiidae) under chronic exposure to cadmium and tributyltin.
    Journal of Environmental Science and Health Part A, 2016
    Co-Authors: Katharina Ruppert, Cornelia Geiß, Sina Ostermann, Christina Theis, Jörg Oehlmann
    Abstract:

    ABSTRACTTo investigate a potential extension of a partial life cycle test protocol to a full life cycle test design, a comparative sensitivity analysis with juvenile and adult Potamopyrgus Antipodarum was performed. Neonates and adult snails were exposed to the metal cadmium (Cd) and the endocrine disruptor tributyltin (TBT) at nominal concentrations ranging from 1.56 to 50 μg Cd/L and from 25 to 1,000 ng TBT-Sn/L. The experiments were performed over 28 days at 16°C in a semi-static test design. Mortality was assessed for both life stages. Juvenile snails' specific growth rate and reproduction of adults were investigated as main endpoints. We determined effects on snails' survival, juvenile growth and embryo numbers in the brood pouch of adult snails under exposure to both chemicals. Juvenile control mortality was between 25% and 30% and significantly higher than in the control groups with adult snails. A higher sensitivity of juvenile snails compared to adults was observed for the endpoint mortality. Cal...

  • IDENTIFICATION OF OESTROGEN-RESPONSIVE TRANSCRIPTS IN Potamopyrgus Antipodarum
    Journal of Molluscan Studies, 2012
    Co-Authors: Daniela Stange, Jörg Oehlmann
    Abstract:

    The freshwater caenogastropod Potamopyrgus Antipodarum is a promising test species for partial lifecycle toxicity testing and also for studies of endocrine disruptors. However, endocrine signalling pathways and the genes/transcripts involved are barely identified and characterized in this snail. We therefore performed whole transcriptome sequencing (454 pyrosequencing), selected transcripts that are known to be hormone-responsive in vertebrates and determined their expression via quantitative real-time PCR after 24 h exposure to the oestrogens 17a-ethinyloestradiol (EE2) and 17b-oestradiol (E2). Examined mRNAs were: nuclear receptors [oestrogen receptor (ER), chicken ovalbumin upstream promoter-transcription factor (COUP-TF), ecdysone-induced protein (E75)], repressors of oestrogen-induced activity [prohibitin-2 (PHB-2), striatin (STRN)] and the egg yolk precursor vitellogenin (VTG). Significantly increased expression by EE2 and E2 treatment was detected for ER and VTG. E2 induced significant upregulation of E75, PHB-2 and STRN, while EE2 did not. COUP-TF expression was unaffected by EE2 or by E2. Variations between replicates were higher in snails exposed to EE2 than to E2. The identification of these oestrogen-responsive transcripts contributes to a better characterization of the endocrine system of P. Antipodarum and provides possible biomarkers for the detection of endocrine disruption.

  • Freshwater mudsnail (Potamopyrgus Antipodarum) estrogen receptor: identification and expression analysis under exposure to (xeno-)hormones.
    Ecotoxicology and Environmental Safety, 2012
    Co-Authors: Daniela Stange, Agnes Sieratowicz, Ralf Horres, Jörg Oehlmann
    Abstract:

    Abstract Molluscs are raising attention as ecotoxicological test organisms due to their high diversity and ecological importance. The ovoviviparous prosobranch gastropod Potamopyrgus Antipodarum (freshwater mudsnail) responds very sensitively to xenobiotics and has therefore been proposed as OECD standard test organism. Endocrine disrupting chemicals influence the reproduction of P. Antipodarum , which can be assessed by embryo numbers in the brood pouch. However, the knowledge about the endocrine system of P. Antipodarum is rather limited. The aim of this study was to identify an estrogen receptor in the endocrine system of P. Antipodarum and to investigate if this receptor is differentially expressed under exposure to (xeno-)hormones (17α-ethinylestradiol, bisphenol A and 17α-methyltestosterone). The DNA-binding domain of the identified ER-like transcript has an amino acid identity of 92 percent compared to the ER of the gastropod Nucella lapillus (84 percent to human ERα) and 83 percent in the ligand binding domain (38 percent to human ERα). Furthermore, the P. Antipodarum ER is transcriptionally regulated as shown by quantitative real-time PCRs of (xeno-)hormone exposed snails. 17α-ethinylestradiol and bisphenol A exposure resulted in a transitory ER-mRNA increase while17α-methyltestosterone caused a transitory reduction of ER-mRNA. In addition the solvent dimethyl sulfoxide had also a modulating effect on the receptor.

  • Reproductive toxicity of bisphenol A and cadmium in Potamopyrgus Antipodarum and modulation of bisphenol A effects by different test temperature.
    Environmental Pollution, 2011
    Co-Authors: Agnes Sieratowicz, Daniela Stange, Ulrike Schulte-oehlmann, Jörg Oehlmann
    Abstract:

    An OECD initiative for the development of mollusc-based toxicity tests for endocrine disrupters and other chemicals has recommended three test species with respective test designs for further standardisation. Preparing a subsequent pre-validation study we performed a reproduction test with Potamopyrgus Antipodarum, determining the concentration range of the selected test substances, bisphenol A (BPA) and cadmium (Cd). At 16 °C, the recommended test temperature, the number of embryos in the brood pouch was increased by BPA and decreased by Cd (NOEC: 20 μg BPA/L and 1 μg Cd/L). Coinstantaneous BPA tests at 7 °C and 25 °C demonstrated a temperature dependency of the response, resulting in lower NOECs (5 μg/L respectively). As expected, reproduction in control groups significantly varied depending on temperature. Additional observations of the brood stock showed seasonal fluctuations in reproduction under constant laboratory conditions. The recommended temperature range and test conditions have to be further investigated.

Maurine Neiman - One of the best experts on this subject based on the ideXlab platform.

  • Genetic Variation for Mitochondrial Function in the New Zealand Freshwater Snail Potamopyrgus Antipodarum.
    Journal of Heredity, 2017
    Co-Authors: Joel Sharbrough, Jennifer L. Cruise, Megan Beetch, Nicole M Enright, Maurine Neiman
    Abstract:

    The proteins responsible for mitochondrial function are encoded by 2 different genomes with distinct inheritance regimes, rendering rigorous inference of genotype-phenotype connections intractable for all but a few model systems. Asexual organisms provide a powerful means to address these challenges because offspring produced without recombination inherit both nuclear and mitochondrial genomes from a single parent. As such, these offspring inherit mitonuclear genotypes that are identical to the mitonuclear genotypes of their parents and siblings but different from those of other asexual lineages. Here, we compared mitochondrial function across distinct asexual lineages of Potamopyrgus Antipodarum, a New Zealand freshwater snail model for understanding the evolutionary consequences of asexuality. Our analyses revealed substantial phenotypic variation across asexual lineages at 3 levels of biological organization: mitogenomic, organellar, and organismal. These data demonstrate that different asexual lineages have different mitochondrial function phenotypes, likely reflecting heritable variation (i.e., the raw material for evolution) for mitochondrial function in P. Antipodarum. The discovery of this variation combined with the methods developed here sets the stage to use P. Antipodarum to study central evolutionary questions involving mitochondrial function, including whether mitochondrial mutation accumulation influences the maintenance of sexual reproduction in natural populations.

  • Distinct Bacterial Microbiomes in Sexual and Asexual Potamopyrgus Antipodarum, a New Zealand Freshwater Snail.
    PLOS ONE, 2016
    Co-Authors: Cristina Takacs-vesbach, Katelyn Larkin, Kayla C. King, David J. Van Horn, Maurine Neiman
    Abstract:

    Different reproductive strategies and the transition to asexuality can be associated with microbial symbionts. Whether such a link exists within mollusks has never been evaluated. We took the first steps towards addressing this possibility by performing pyrosequencing of bacterial 16S rRNA genes associated with Potamopyrgus Antipodarum, a New Zealand freshwater snail. A diverse set of 60 tissue collections from P. Antipodarum that were genetically and geographically distinct and either obligately sexual or asexual were included, which allowed us to evaluate whether reproductive mode was associated with a particular bacterial community. 2624 unique operational taxonomic units (OTU, 97% DNA similarity) were detected, which were distributed across ~30 phyla. While alpha diversity metrics varied little among individual samples, significant differences in bacterial community composition and structure were detected between sexual and asexual snails, as well as among snails from different lakes and genetic backgrounds. The mean dissimilarity of the bacterial communities between the sexual and asexual P. Antipodarum was 90%, largely driven by the presence of Rickettsiales in sexual snails and Rhodobacter in asexual snails. Our study suggests that there might be a link between reproductive mode and the bacterial microbiome of P. Antipodarum, though a causal connection requires additional study.

  • Response to Phosphorus Limitation Varies among Lake Populations of the Freshwater Snail Potamopyrgus Antipodarum
    2016
    Co-Authors: Amy C. Krist, Katelyn Larkin, Adam D. Kay, Maurine Neiman
    Abstract:

    Local adaptation – typically recognized as higher values of fitness-related traits for native vs. non-native individuals when measured in the native environment- is common in natural populations because of pervasive spatial variation in the intensity and type of natural selection. Although local adaptation has been primarily studied in the context of biotic interactions, widespread variation in abiotic characteristics of environments suggests that local adaptation in response to abiotic factors should also be common. Potamopyrgus Antipodarum, a freshwater New Zealand snail that is an important model system for invasion biology and the maintenance of sexual reproduction, exhibits local adaptation to parasites and rate of water flow. As an initial step to determining whether P. Antipodarum are also locally adapted to phosphorus availability, we examined whether populations differ in their responses to phosphorus limitation. We found that field-collected juvenile P. Antipodarum grew at a lower rate and reached an important size threshold more slowly when fed a relatively low vs. a relatively high- phosphorus diet. We also detected significant across-population variation in individual growth rate. A marginally significant population-by-dietary phosphorus interaction along with a two-fold difference across populations in the extent of suppression of growth by low phosphorus suggests that populations of P. Antipodarum may differ in their response to phosphorus limitation. Local adaptation may explain this variation, with the implication that snails from lakes with relatively low phosphorus availability should be less severely affected by phosphorus limitation than snail

  • Mitochondrial (cytochrome b) haplotypes in Potamopyrgus Antipodarum (with outgroup)
    2016
    Co-Authors: Dorota Paczesniak, Jukka Jokela, Katelyn Larkin, Maurine Neiman
    Abstract:

    Sequences of unique haplotypes of mitochondrial cytochrome-b fragment in Potamopyrgus Antipodarum. Homologous sequence for related species (P. estuarinus) is included an an outgroup

  • Discordance between nuclear and mitochondrial genomes in sexual and asexual lineages of the freshwater snail Potamopyrgus Antipodarum.
    Molecular Ecology, 2013
    Co-Authors: Dorota Paczesniak, Jukka Jokela, Katelyn Larkin, Maurine Neiman
    Abstract:

    The presence and extent of mitonuclear discordance in coexisting sexual and asexual lineages provides insight into 1) how and when asexual lineages emerged, and 2) the spatial and temporal scales at which the ecological and evolutionary processes influencing the evolution of sexual and asexual reproduction occur. Here, we used nuclear single-nucleotide polymorphism (SNP) markers and a mitochondrial gene to characterize phylogeographic structure and the extent of mitonuclear discordance in Potamopyrgus Antipodarum. This New Zealand freshwater snail is often used to study the evolution and maintenance of sex because obligately sexual and obligately asexual individuals often coexist. While our data indicate that sexual and asexual P. Antipodarum sampled from the same lake population are often genetically similar, suggesting recent origin of these asexuals from sympatric sexual P. Antipodarum, we also found significantly more population structure in sexuals vs. asexuals. This latter result suggests that some asexual lineages originated in other lakes and/or in the relatively distant past. When comparing mitochondrial and nuclear population genetic structure, we discovered that one mitochondrial haplotype (‘1A’) was rare in sexuals, but common and widespread in asexuals. Haplotype 1A frequency and nuclear genetic diversity were not associated, suggesting that the commonness of this haplotype cannot be attributed entirely to genetic drift and pointing instead to a role for selection.