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identification and characterization of a novel conserved 46 kd maltoporin of aeromonas hydrophila as a versatile vaccine candidate in european eel (anguilla anguilla).european eel (anguilla anguilla) is a crucial economic fish that has been plagued by aeromonas hydrophila infections for many years. vaccines that are cross-protective against multiple serotypes could provide an effective control against a. hydrophila-mediated diseases. the outer membrane proteins (omps) are highly immunogenic and capable of eliciting protective immune responses. this study reports the identification of a novel 46 kd maltoporin that is a conserved protective antigen for differen ...201728279793
the effect of foraging and ontogeny on the prevalence and intensity of the invasive parasite anguillicola crassus in the european eel anguilla anguilla.infection patterns of the invasive anguillicola crassus nematode were investigated in a population of the european eel anguilla anguilla where parasite invasion is very recent, loch lomond, scotland. intensity levels of the parasite were associated with differences in fish ontogeny and trophic ecology. although eels foraged on both fish and invertebrates, individuals which were smaller and fed on invertebrates (>70% contribution to diet) were found to contain a greater number of swim bladder par ...201728084623
ubiquitous distribution of fluorescent protein in muscles of four species and two subspecies of eel (genus anguilla).in this study, the localization of fluorescent protein (fp) was characterized in the muscles of four species and two subspecies of eels anguilla anguilla, a. australis, a. bicolor bicolor (b.), a. bicolor pacifica (p.) and a. mossambica in addition to the previously reported a. japonica. the open reading frame of each eel fp was 417 bp encoding 139 amino acid residues. the deduced amino acid sequences among the four species and two subspecies exhibited 91.4-100% identity, and belonged to the fat ...201728360397
role of potassium and ph on the initiation of sperm motility in the european eel.the role of potassium from the seminal plasma and/or the activation media was examined by selectively removing k(+) from this media, and by testing the use of k(+) channel inhibitors and a k-ionophore. sperm motility was measured using a casa system, intracellular k(+) and ph were measured by flow cytometry, and sperm head area was measured by asma: automated sperm morphometry analyses. sperm motility was notably inhibited by the removal of k(+) from the seminal plasma and by treatment with the ...201727693817
the expression of nuclear and membrane estrogen receptors in the european eel throughout spermatogenesis.estradiol (e2) can bind to nuclear estrogen receptors (esr) or membrane estrogen receptors (gper). while mammals possess two nuclear esrs and one membrane gper, the european eel, like most other teleosts, has three nuclear esrs and two membrane gpers, as the result of a teleost specific genome duplication. in the current study, the expression of the three nuclear esrs (esr1, esr2a and esr2b) and the two membrane gpers (gpera and gperb) in the brain-pituitary-gonad (bpg) axis of the european eel ...201727590411
silvering and swimming effects on aerobic metabolism and reactive oxygen species in the european eel.silvering, the last metamorphosis in the eel life cycle induces morphological and physiological modifications in yellow eels (sedentary stage). it pre-adapts them to cope with the extreme conditions they will encounter during their 6000-km spawning migration. a previous study showed that silver eels are able to cope with reactive oxygen species (ros) over-production linked to an increase in aerobic metabolism during sustained swimming, but the question remains as to whether this mechanism is ass ...201727717909
the chromogranin a-derived sympathomimetic serpinin depresses myocardial performance in teleost and amphibian hearts.chromogranin a (cga) is an acidic protein co-stored with catecholamines, hormones and neuropeptides in the secretory granules of endocrine, neuronal and other cell types (including cardiomyocytes). proteolytic cleavage in the c terminus of cga generates a 2.9kda peptide named serpinin (serp; ala26leu) that can be modified at its n terminus to form a pyroglutamate residue (pglu-serp). in the rat heart, both peptides increase contractility and relaxation through a β-adrenergic-like action mechanis ...201727633326
development of sperm vitrification protocols for freshwater fish (eurasian perch, perca fluviatilis) and marine fish (european eel, anguilla anguilla).vitrification was successfully applied to the sperm of two fish species, the freshwater eurasian perch (perca fluviatilis) and marine european eel (anguilla anguilla). sperm was collected, diluted in species-specific non-activating media and cryoprotectants and vitrified by plunging directly into liquid nitrogen without pre-cooling in its vapor. progressive motility of fresh and vitrified-thawed sperm was evaluated with computer-assisted sperm analysis (casa). additional sperm quality parameters ...201727174751
angiotensin ii dependent cardiac remodeling in the eel anguilla anguilla involves the nos/no system.angiotensin ii (angii), the principal effector of the renin-angiotensin system (ras), plays an important role in controlling mammalian cardiac morpho-functional remodelling. in the eel anguilla anguilla, one month administration of angii improves cardiac performance and influences the expression and localization of molecules which regulate cell growth. to deeper investigate the morpho-functional chronic influences of angii on the eel heart and the molecular mechanisms involved, freshwater eels ( ...201728232085
nuclear and membrane progestin receptors in the european eel: characterization and expression in vivo through spermatogenesis.characterization of all the progestin receptor genes (prs) found in the european eel has been performed. there were five membrane prs (mprs): mprα (alpha), mpral1 (alpha-like1), mpral2 (alpha-like2), mprγ (gamma), mprδ (delta) and two nuclear prs (nprs or pgrs): pgr1 and pgr2. in silico studies showed that the c and e(f) domains of pgr are well conserved among vertebrates whereas the a/b domain is not. phylogeny and synteny analyses suggest that eel duplicated pgr (pgr1 and pgr2) originated from ...201728196764
migratory behavior, metabolism, oxidative stress and mercury concentrations in marine and estuarine european glass eels (anguilla anguilla).the relationships between the migratory behavior, methylmercury (mehg) concentrations, oxidative stress response and detoxification processes were investigated in glass eels collected in marine (molliets) and estuarine (urt) waters (adour estuary, south west france) at the end of the fishing season (april). glass eel migratory behavior was investigated in an experimental flume according to their response to dusk. fish responding to the decrease in light intensity by ascending in the water column ...201727864042
assessing pre- and post-zygotic barriers between north atlantic eels (anguilla anguilla and a. rostrata).elucidating barriers to gene flow is important for understanding the dynamics of speciation. here we investigate pre- and post-zygotic mechanisms acting between the two hybridizing species of atlantic eels: anguilla anguilla and a. rostrata. temporally varying hybridization was examined by analyzing 85 species-diagnostic single-nucleotide polymorphisms (snps; fst ⩾0.95) in eel larvae sampled in the spawning region in the sargasso sea in 2007 (n=92) and 2014 (n=460). we further investigated wheth ...201727827390
how the european eel (anguilla anguilla) loses its skeletal framework across lifetime.european eels (anguilla anguilla) undertake an impressive 5 000 km long migration from european fresh waters through the north atlantic ocean to the sargasso sea. along with sexual maturation, the eel skeleton undergoes a remarkable morphological transformation during migration, where a hitherto completely obscure bone loss phenomenon occurs. to unravel mechanisms of the maturation-related decay of the skeleton, we performed a multiscale assessment of eels' bones at different life-cycle stages. ...201627798301
evidence for high concentrations and maternal transfer of substituted diphenylamines in european eels analyzed by two-dimensional gas chromatography-time-of-flight mass spectrometry and gas chromatography-fourier transform ion cyclotron resonance mass spectrometry.chemical pollution is hypothesized to be one of the factors driving the strong decline of the critically endangered european eel population. specifically, the impact of contaminants on the quality of spawning eels and subsequent embryo survival and development has been discussed as crucial investigation point. however, so far, only very limited information on potential negative effects of contaminants on the reproduction of eels is available. through the combination of nontargeted ultrahigh-reso ...201627791360
radionuclides ((210)po and (210)pb) and some heavy metals in fish and sediments in lake bafa, turkey, and the contribution of (210)po to the radiation dose.the pollution level of lake bafa was investigated by collecting fish samples {dicentrarchus labrax (sea bass), liza ramada (mullet) and anguilla anguilla (eel)}, surface sediment, and core samples. in all these samples, (210)po and (210)pb concentrations were estimated, and total annual dose rates were obtained for each species. some heavy metal (cr, ni, pb, cd, mn, fe, and zn) concentration levels were obtained for the fish and a core sample. the sediment mass accumulation rate was found to be ...201627834886
detecting the exposure to cd and pcbs by means of a non-invasive transcriptomic approach in laboratory and wild contaminated european eels (anguilla anguilla).detecting and separating specific effects of contaminants in a multi-stress field context remain a major challenge in ecotoxicology. in this context, the aim of this study was to assess the usefulness of a non-invasive transcriptomic method, by means of a complementary dna (cdna) microarray comprising 1000 candidate genes, on caudal fin clips. fin gene transcription patterns of european eels (anguilla anguilla) exposed in the laboratory to cadmium (cd) or a polychloro-biphenyl (pcbs) mixture but ...201626566612
rad sequencing reveals within-generation polygenic selection in response to anthropogenic organic and metal contamination in north atlantic eels.measuring the effects of selection on the genome imposed by human-altered environment is currently a major goal in ecological genomics. given the polygenic basis of most phenotypic traits, quantitative genetic theory predicts that selection is expected to cause subtle allelic changes among covarying loci rather than pronounced changes at few loci of large effects. the goal of this study was to test for the occurrence of polygenic selection in both north atlantic eels (european eel, anguilla angu ...201626562221
cutaneous myxidiosis in european eel, anguilla anguilla (linnaeus, 1758): histopathology, histochemistry and laminin immunohistochemistry.histopathology, histochemistry and immunohistochemistry of the integument of european eel, anguilla anguilla (linnaeus, 1758), infected by myxidium sp. are reported. skin samples from affected and unaffected eels were dissected, formalin fixed, paraffin embedded, sectioned and stained with h&e, periodic acid-schiff's staining method, alcian blue 8 gx ph 2.5/periodic acid-schiff's and mccallum-goodpasture's gram stain. moreover, immunohistochemistry was performed using a primary polyclonal lamini ...201626525491
a question of origin: dioxin-like pcbs and their relevance in stock management of european eels.the stock of european eel (anguilla anguilla l.) has reached an all-time low in 2011. spawner quality of mature eels in terms of health status and fitness is considered one of the key elements for successful migration and reproduction. dioxin-like polychlorinated biphenyls (dl-pcbs) are known persistent organic pollutants potentially affecting the reproductive capability and health status of eels throughout their entire lifetime. in this study, muscle tissue samples of 192 european eels of all c ...201626477019
role of calcium on the initiation of sperm motility in the european eel.sperm from european eel males treated with hcgrec was washed in a calcium free extender, and sperm motility was activated both in the presence (seawater, sw) and in the absence of calcium (nacl+edta), and treated with calcium inhibitors or modulators. the sperm motility parameters were evaluated by a computer-assisted sperm analysis (casa) system, and changes in the [ca(2+)]i fluorescence (and in [na(+)]i in some cases) were evaluated by flow cytometry. after sperm motility was activated in a me ...201626459984
protective responses of intestinal mucous cells in a range of fish-helminth systems.histopathological, immunofluorescence and ultrastructural studies were conducted on the intestines of four fish species infected with different taxa of enteric helminths. brown trout (salmo trutta trutta), eel (anguilla anguilla) and tench (tinca tinca) obtained from lake piediluco (central italy) were examined. brown trout and eel were infected with two species of acanthocephalans, and tench was parasitized with a tapeworm species. in addition to the above site, specimens of chub (squalius ceph ...201628026022
bile metabolites of polycyclic aromatic hydrocarbons (pahs) in three species of fish from morocco.polycyclic aromatic hydrocarbons (pah) are environmental contaminants that pose significant risk to health of fish. environmental pollution of fish is a topic of rising attention in morocco. however, only few studies have been carried out so far, describing the potential threat of organic pollution to moroccan aquatic ecosystem. two polycyclic aromatic hydrocarbon (pah) metabolites, 1-hydroxypyrene (1-oh-pyr) and 1-hydroxyphenanthrene (1-oh-phen), were identified and quantified from the bile of ...201627867806
an outbreak of shewanella putrefaciens group in wild eels anguilla anguilla l. favoured by hypoxic aquatic environments.microbiological analyses were conducted on wild eels from the l'albufera lake (spain). a total of 174 individuals were collected in two surveys (i.e. year 2008 and autumn-winter 2014) among those caught by local fishermen into the lagoon. the prevalence of shewanella putrefaciens group was 1.7% in 2008 and rose above 32% in 2014. it was due to an outbreak of shewanellosis that presented a morbidity rate of 64%. s. putrefaciens group strains were isolated as pure cultures from the sick eels that ...201627982438
abundance of specific mrna transcripts impacts hatching success in european eel, anguilla anguilla l.maternal mrna governs early embryonic development in fish and variation in abundance of maternal transcripts may contribute to variation in embryonic survival and hatch success in european eel, anguilla anguilla. previous studies have shown that quantities of the maternal gene products β-tubulin, insulin-like growth factor 2 (igf2), nucleoplasmin (npm2), prohibitin 2 (phb2), phosphatidylinositol glycan biosynthesis class f protein 5 (pigf5), and carnitine o-palmitoyltransferase liver isoform-lik ...201626415730
maternally transferred dioxin-like compounds can affect the reproductive success of european eel.reported concentrations of dioxin-like compounds accumulated in the european eel (anguilla anguilla) were used to perform a risk assessment for eel larval survival, taking into account a modeled amplification of tissue concentrations with a factor of 1.33 during spawning migration. the calculated concentrations of dioxin-like compounds finally deposited in the eggs were compared with the internal effect concentrations for survival of early life stages of the european eel; these concentrations, b ...201626223357
histological and hormonal changes in the european eel (anguilla anguilla) after exposure to environmental cocaine concentration.the aim of this study was the assessment of histological and hormonal changes induced in the european eel from environmental concentrations of cocaine. silver eels were exposed to 20 ng l(-1) of cocaine during 50 days; at the same time, control, vehicle control and two post-exposure recovery groups (3 and 10 days) were made. the general morphology of the skin and the intestine, and the plasma levels of prolactin, cortisol and dopamine were evaluated. in the skin, cocaine decreased the number and ...201625865023
effects of salinity and sea salt type on egg activation, fertilization, buoyancy and early embryology of european eel, anguilla anguilla.improper activation and swelling of in vitro produced eggs of european eel, anguilla anguilla, has been shown to negatively affect embryonic development and hatching. we investigated this phenomenon by examining the effects of salinity and sea salt type on egg dimensions, cell cleavage patterns and egg buoyancy. egg diameter after activation, using natural seawater adjusted to different salinities, varied among female eels, but no consistent pattern emerged. activation salinities between 30-40 p ...201625707438
development and validation of a real-time pcr assay for the detection of anguillid herpesvirus 1.anguillid herpesvirus 1 (anghv1) causes a haemorrhagic disease with increased mortality in wild and farmed european eel, anguilla anguilla (l.) and japanese eel anguilla japonica, temminck & schlegel). detection of anghv1 is currently based on virus isolation in cell culture, antibody-based typing assays or conventional pcr. we developed, optimized and concisely validated a diagnostic taqman probe based real-time pcr assay for the detection of anghv1. the primers and probe target anghv1 open rea ...201625588414
changes in ovarian gene expression profiles and plasma hormone levels in maturing european eel (anguilla anguilla); biomarkers for broodstock selection.complete sexual maturation of european eels (anguilla anguilla) in captivity can only be achieved via injections with gonadotropins. for female eels this procedure takes 4-6months and the response ranges from "unresponsive" to final maturation and ovulation. reproductive success could be significantly increased via early selection of responders based on predictive markers and minimally invasive sampling methods. to get a better understanding of the genetic background of ovarian maturation of the ...201626255685
ultrasonographic predictors of response of european eels (anguilla anguilla) to hormonal treatment for induction of ovarian development.objective to examine ultrasonographic predictors of ovarian development in european eels (anguilla anguilla) undergoing hormonal treatment for assisted reproduction. animals 83 female european eels. procedures eels received weekly im injections of salmon pituitary extract (first injection = week 1). ultrasonography of the ovaries was performed twice during hormonal treatment (weeks 7 and 11). eels were identified on the basis of body weight as having an adequate response by weeks 14 to 20 or an ...201627111015
sodium affects the sperm motility in the european eel.the role of seminal plasma sodium and activation media sodium on sperm motility was examined by selectively removing the element from these two media, in european eel sperm. sperm size (sperm head area) was also measured using an asma (automated sperm morphometry analyses) system, in the different conditions. intracellular sodium [na(+)]i was quantitatively analyzed by first time in the spermatozoa from a marine fish species. measurement of [na(+)]i was done before and after motility activation, ...201627085371
evaluating the adaptive potential of the european eel: is the immunogenetic status recovering?the recent increased integration of evolutionary theory into conservation programs has greatly improved our ability to protect endangered species. a common application of such theory links population dynamics and indices of genetic diversity, usually estimated from neutrally evolving markers. however, some studies have suggested that highly polymorphic adaptive genes, such as the immune genes of the major histocompatibility complex (mhc), might be more sensitive to fluctuations in population dyn ...201627077000
an ultrastructural and immunohistochemical analysis of the outer plexiform layer of the retina of the european silver eel (anguilla anguilla l).here we studied the ultrastructural organization of the outer retina of the european silver eel, a highly valued commercial fish species. the retina of the european eel has an organization very similar to most vertebrates. it contains both rod and cone photoreceptors. rods are abundantly present and immunoreactive for rhodopsin. cones are sparsely present and only show immunoreactivity for m-opsin and not for l-, s- or uv-cone opsins. as in all other vertebrate retinas, müller cells span the wid ...201627032102
temperature modulates testis steroidogenesis in european eel.this study evaluates the effects of temperature on hcg-induced spermatogenesis in european eel (anguilla anguilla), subjected to three thermal regimes: t10: 10°c (first 4weeks), 15°c (next 3weeks) and 20°c (last 6weeks); t15: 15°c (first 4weeks) and 20°c (last 9weeks); and t20: constant 20°c for the duration of the experiment. at 10°c, maturation stopped in the a spermatogonial stage (spg1), and no further maturation was observed until the temperature was ≥15°c. with the aim of explaining these ...201627013359
phagocytic cell responses to silica-coated dithiocarbamate-functionalized iron oxide nanoparticles and mercury co-exposures in anguilla anguilla l.immune system responses in fish are considered as suitable and sensitive biomarkers for monitoring aquatic pollution. however, a clear knowledge gap persists in the literture on the immunotoxic potential of engineered nanoparticles toward aquatic organisms such as fish. employing major enzymatic- (glutathione reductase, gr; glutathione peroxidase, gpx; glutathione sulfo-transferase, gst; catalase, cat) and thiol- (non-protein thiols, np-sh; total glutathione, tgsh)-based defense biomarkers, this ...201626976012
are biometric parameters helpful to assess the health risk of consuming organochlorine compounds contaminated silver european eel (anguilla anguilla)?several organochlorine compounds (ocs) were measured in european eels from the tevere river (italy). it followed that some of them are still important chemical contaminants. concentrations of dichlorodiphenyltrichloroethanes (ddts) are hazardous for the consumer health; those of the 6 indicator polychlorinated biphenyls (pcbs) are often close to the current european maximum residue limit and always higher than the former limit. the relationship between oc concentrations, biometric parameters and ...201626953718
rapid recovery following short-term acoustic disturbance in two fish species.noise from human activities is known to impact organisms in a variety of taxa, but most experimental studies on the behavioural effects of noise have focused on examining responses associated with the period of actual exposure. unlike most pollutants, acoustic noise is generally short-lived, usually dissipating quickly after the source is turned off or leaves the area. in a series of experiments, we use established experimental paradigms to examine how fish behaviour and physiology are affected, ...201626909193
to boldly climb: behavioural and cognitive differences in migrating european glass eels.european eel (anguilla anguilla) is a catadromous fish species that received substantial attention as its population has markedly declined in the last three decades. the possible causes of this decline include habitat fragmentation factors such as dams and weirs. in some cases, these obstacles are equipped with fish friendly passage devices that may select young eels according to their climbing behaviour. we tested how individual climbing tendency was related to the event of fishway passage expe ...201626909192
first evidence of european eels exiting the mediterranean sea during their spawning migration.the migration route and the spawning site of the european eel anguilla anguilla are still uncertain. it has been suggested that the mediterranean eel stock does not contribute to spawning because there is no evidence of eels leaving the mediterranean sea. to test this hypothesis, we equipped eight female silver eels from the south of france with pop-up satellite tags during escapement from coastal waters. once in deeper water, the eels quickly established diel vertical migration (dvm) between th ...201626906289
kleptoparasitism and aggressiveness are influenced by standard metabolic rate in eels.kleptoparasitism refers to either interspecific or intraspecific stealing of food already procured by other species or individuals. within a given species, individuals might differ in their propensity to use such a tactic, in a similar manner to which they differ in their general level of aggressiveness. standard metabolic rate is often viewed as a proxy for energy requirements. for this reason, it should directly impact on both kleptoparasitism and aggressiveness when individuals have to share ...201626861178
diet-induced phenotypic plasticity in european eel (anguilla anguilla).two phenotypes are present within the european eel population: broad-heads and narrow-heads. the expression of these phenotypes has been linked to several factors, such as diet and differential growth. the exact factors causing this dimorphism, however, are still unknown. in this study, we performed a feeding experiment on glass eels from the moment they start to feed. eels were either fed a hard diet, which required biting and spinning behavior, or a soft diet, which required suction feeding. w ...201626847560
thyroid endocrine status of wild european eels (anguilla anguilla) in the loire (france). relationships with organic contaminant body burdens.in teleost fish, thyroid function is involved in various critical physiological processes. given the complexity of the hypothalamo-pituitary-thyroid (hpt) axis, a large number of genes and proteins can be the potential target of endocrine-disrupting compounds (edcs). the aim of this study was to evaluate, in yellow and silver european eels (anguilla anguilla), potential effects of edcs on thyroid status by analyzing the associations between edc body burdens and thyroid hormones (ths). in yellow ...201626845177
using a novel "integrated biomarker proteomic" index to assess the effects of freshwater pollutants in european eel peripheral blood mononuclear cells.using proteomic data as biomarkers of environmental pollution has the potential to be of a great interest in ecological risk assessment as they constitute early warning indicators of ecologically relevant effects on biological systems. to develop such specific and sensitive biomarkers, the use of a set of proteins is required and the identification of protein expression signatures (pes) may reflect the exposure to specific classes of pollutants. using 2d-dige (differential in gel electrophoresis ...201626785284
species complexes and phylogenetic lineages of hoferellus (myxozoa, cnidaria) including revision of the genus: a problematic case for taxonomy.myxozoans are metazoan parasites whose traditional spore morphology-based taxonomy conflicts dna based phylogenies. freshwater species of the genus hoferellus are parasites of the excretory system, with several members infecting food and ornamental fish species, as well as amphibians. this study aims to increase our understanding of their molecular diversity and development, aspects about which little is known, and to generate a molecular diagnostic tool to discriminate between different pathoge ...201626754529
brominated, chlorinated and mixed brominated/chlorinated persistent organic pollutants in european eels (anquilla anquilla) from latvian lakes.fifty-eight european eel (anquilla anquilla) specimens collected from five latvian lakes were investigated for six groups of persistent organic pollutants (pops), including polychlorinated, polybrominated and mixed bromo-chloro dibenzo-p-dioxins and dibenzofurans (pcdd/dfs, pbdd/dfs and pxdd/dfs), polychlorinated and mixed bromo-chloro biphenyls (pcbs and pxbs) and polybrominated diphenyl ethers (pbdes). pcdd/dfs and pcbs were found to occur in the range 0.85-15.8 pg total-who2005-teq g(-1) f.w. ...201626730547
freshwater and coastal migration patterns in the silver-stage eel anguilla anguilla.the unimpeded downstream movement patterns and migration success of small female and male anguilla anguilla through a catchment in north-west europe were studied using an acoustic hydrophone array along the river finn and into the foyle estuary in ireland. twenty silver-stage a. anguilla (total length, lt , range: 332-520 mm) were trapped 152 km upstream from a coastal marine sea-lough outlet and internally tagged with acoustic transmitters of which 19 initiated downstream migration. migration s ...201626707686
condition-dependent physiological and behavioural responses to anthropogenic noise.anthropogenic (man-made) noise, a global pollutant of international concern, is known to affect the physiology and behaviour of a range of organisms. however, experimental studies have tended to focus on trait means; intra-population variation in responses are likely, but have rarely been explored. here we use established experimental methods to demonstrate a condition-dependent effect of additional noise. we show that juvenile european eels (anguilla anguilla) in good condition do not respond d ...201626686756
the effects of hypoxic bradycardia and extracellular hco3(-)/co2 on hypoxic performance in the eel heart.during hypoxia, fishes exhibit a characteristic hypoxic bradycardia, the functional significance of which remains debated. here, we investigated the hypothesis that hypoxic bradycardia primarily safeguards cardiac performance. in preparations from the european eel (anguilla anguilla), a decrease in stimulation frequency from 40 to 15 beats min(-1), which replicates hypoxic bradycardia in vivo, vastly improved cardiac performance during hypoxia in vitro. as eels display dramatic shifts in extrace ...201626596533
maximal oxygen consumption increases with temperature in the european eel (anguilla anguilla) through increased heart rate and arteriovenous extraction.global warming results in increasing water temperature, which may represent a threat to aquatic ectotherms. the rising temperature affects ecology through physiology, by exerting a direct limiting effect on the individual. the mechanism controlling individual thermal tolerance is still elusive, but some evidence shows that the heart plays a central role, and that insufficient transport of oxygen to the respiring tissues may determine the thermal tolerance of animals. in this study, the influence ...201627766150
evidences of dna and chromosomal damage induced by the mancozeb-based fungicide mancozan(®) in fish (anguilla anguilla l.).the formulation mancozan(®), containing mancozeb as active ingredient, is among the most widely used fungicides. although mancozeb has been detected in surface waters, studies addressing the genotoxic risk to fish arising from the use of this formulation, testing environmentally realistic concentrations, are absent from the literature. hence, this work aimed to investigate the dna and chromosome damaging potential of mancozan(®) (0.29 and 2.9μgl(-1)) in the european eel (anguilla anguilla l.), a ...201627742361
empirical observations of the spawning migration of european eels: the long and dangerous road to the sargasso sea.the spawning migration of the european eel (anguilla anguilla l.) to the sargasso sea is one of the greatest animal migrations. however, the duration and route of the migration remain uncertain. using fishery data from 20 rivers across europe, we show that most eels begin their oceanic migration between august and december. we used electronic tagging techniques to map the oceanic migration from eels released from four regions in europe. of 707 eels tagged, we received 206 data sets. many migrati ...201627713924
accumulation of persistent organic pollutants in consumers of eel from polluted rivers compared to marketable eel.globally, many river sediments are seriously contaminated with persistent organic pollutants (pops) known to accumulate in aquatic food. in the netherlands, toxicological risks of human exposure to dioxins and dioxin-like compounds led to a ban on eel fishing in the rhine-meuse delta. the aim of this study is to investigate differences in serum pop levels in consumers of eel from high-polluted areas and consumers of eel from low-polluted areas or aquaculture. in total 80 dutch men were included, ...201627697634
the european eel nccβ gene encodes a thiazide-resistant na-cl cotransporter.the thiazide-sensitive na-cl cotransporter (ncc) is the major pathway for salt reabsorption in the mammalian distal convoluted tubule. ncc plays a key role in the regulation of blood pressure. its inhibition with thiazides constitutes the primary baseline therapy for arterial hypertension. however, the thiazide-binding site in ncc is unknown. mammals have only one gene encoding for ncc. the eel, however, contains a duplicate gene. nccα is an ortholog of mammalian ncc and is expressed in the kidn ...201627587391
does asymmetric gene flow among matrilines maintain the evolutionary potential of the european eel?using evolutionary theory to predict the dynamics of populations is one of the aims of evolutionary conservation. in endangered species, with geographic range extending over continuous areas, the predictive capacity of evolutionary-based conservation measures greatly depends on the accurate identification of reproductive units. the endangered european eel (anguilla anguilla) is a highly migratory fish species with declining population due to a steep recruitment collapse in the beginning of the 1 ...201627551384
a comparison of techniques for studying oogenesis in the european eel anguilla anguilla.a multi-technique approach was used to study the changes occurring in european eel anguilla anguilla ovaries during hormonally-induced vitellogenesis. aside from classic techniques used to monitor the vitellogenic process, such as ovary histology, fat content analysis, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (sds-page) and vitellogenin enzyme linked immunosorbent assay (elisa), a new technique, fourier-transform infrared (ft-ir) microspectroscopy, was used to analyse a. anguil ...201627500665
functional characterisation of eel dopamine d2 receptors and involvement in the direct inhibition of pituitary gonadotrophins.in various vertebrate species, dopamine (da) exerts an inhibitory action on reproduction. in the european eel, da plays a pivotal role in the inhibitory control of gonadotroph function and the blockade of puberty. in vivo studies have suggested that this effect is mediated by receptors pharmacologically related to the d2 family. in the european eel, two distinct d2 receptor (d2-r) paralogous genes have been identified (d2a-r and d2b-r) and both were shown to be expressed in the pituitary. we inv ...201627453551
phthalate metabolites in the european eel (anguilla anguilla) from mediterranean coastal lagoons.the levels and fate of phthalate metabolites have been poorly evaluated in fish, despite their potential ecotoxicological impacts. the present study aims to characterize the levels of phthalate metabolites in muscle tissue of yellow eels (anguilla anguilla) from two coastal mediterranean lagoons, during three sampling periods. nine phthalate metabolites were detected in >70% of the samples. slightly higher levels of phthalate metabolites were detected in march and june compared to october, sugge ...201627412480
a comparison of metal concentrations in the tissues of yellow american eel (anguilla rostrata) and european eel (anguilla anguilla).historically abundant and widespread, populations of atlantic eels have suffered a sharp decline in recent decades, in the ranges 40-80% and 90-99% for american and european eels, respectively. as a result, american eels are now classified as threatened, whereas european eels are considered to be in critical danger of extinction. several causes have been identified as likely contributors of this decline, including overfishing, obstacles to migration (hydroelectric dams), climate change and habit ...201627395077
accumulation of neurotoxic organochlorines and trace elements in brain of female european eel (anguilla anguilla).xenobiotics such as organochlorine compounds (ocs) and metals have been suggested to play a significant role in the collapse of european eel stocks in the last decades. several of these pollutants could affect functioning of the nervous system. still, no information is so far available on levels of potentially neurotoxic pollutants in eel brain. in present study, carried out on female eels caught in belgian rivers and canals, we analyzed brain levels of potentially-neurotoxic trace elements (ag, ...201627376663
methylmercury and total mercury in eels, anguilla anguilla, from lakes in northeastern poland: health risk assessment.in the aquatic environment, mercury is readily methylated into its most toxic form of methylmercury. in this form, it enters the aquatic food chain and its concentrations increase in subsequent links, which decreases the quality of fish meat and poses risks to consumer health. concentrations of methylmercury (mehg) and total mercury (thg) were determined in the muscle tissues of 64 eel specimens measuring from 59 to 95 cm in length as functions of specimen size and weight. risks posed to consume ...201627357082
identification of the major proteins present in the seminal plasma of european eel, and how hormonal treatment affects their evolution. correlation with sperm quality. 201627343370
fipronil and two of its transformation products in water and european eel from the river elbe.fipronil is an insecticide which, based on its mode of action, is intended to be predominantly toxic towards insects. fipronil bioaccumulates and some of its transformation products were reported to be similar or even more stable in the environment and to show an enhanced toxicity against non-target organisms compared to the parent compound. the current study investigated the occurrence of fipronil and two of its transformation products, fipronil-desulfinyl and fipronil-sulfone, in water as well ...201627289396
interactive effects of dietary composition and hormonal treatment on reproductive development of cultured female european eel, anguilla anguilla.farmed female eels were fed two experimental diets with similar proximate composition but different n-3 polyunsaturated fatty acid (pufa) levels. both diets had similar levels of arachidonic acid (ara), while levels of eicosapentaenoic acid (epa) and docosahexaenoic acid (dha) in one diet were approximately 4.5 and 2.6 times higher compared to the other diet, respectively. after the feeding period, each diet group was divided into two and each half received one of two hormonal treatments using s ...201627264530
first production of larvae using cryopreserved sperm: effects of preservation temperature and cryopreservation on european eel sperm fertilization capacity.sperm cryopreservation is a useful tool in captive fish reproduction management, that is to synchronize gamete production, especially in the case of species as the european eel, where the time of female spawning readiness is unpredictable. several protocols to cryopreserve sperm of this species have been described, but until recently fertilization trials were not feasible. this study evaluated the effect of cold storage of diluted sperm prior to fertilizations and tested whether a previously def ...201627189043
morphometric analysis of the hard parts of pseudodactylogyrus anguillae and pseudodactylogyrus bini (monogenea: dactylogyridae) on the gill apparatus of the european eels ( anguilla anguilla ) from the freshwaters of latvia.we investigated the spatial distribution and measured the hard parts of the attachment apparatuses and reproductive organs of the 2 eel-specific monogenean species pseudodactylogyrus anguillae and pseudodactylogyrus bini. comparative analysis focused on parasite microhabitats within the gill apparatus. additionally, we compared the morphometric characteristics of the monogeneans based on geographical locality and seasonality. the attachment apparatus and reproductive organ characteristics of the ...201626741978
anguilla anguilla intestinal immune response to natural infection with contracaecum rudolphii a larvae.the european eel, anguilla anguilla, is a major warm-water fish species cultured in north and south europe. seventy-one a. anguilla collected between 2010 and 2015 from the comacchio lagoons were examined. fish were infected and damaged by larvae (l3) of the nematode contracaecum rudolphii a, which were encapsulated within the thickness of the intestinal wall and within the external visceral peritoneum (serosa). conspicuous granulomas, visible at sites of infection, were arranged in a trilayer, ...201626814373
comparative imaging of european eels (anguilla anguilla) for the evaluation of swimbladder nematode (anguillicoloides crassus) infestation.this study compares diagnostic imaging tools in detecting the parasitic swimbladder nematode anguillicoloides crassus in anguilla anguilla (l.) and focuses on ultrasound in an attempt to develop a non-destructive, field diagnostic test. ultrasound use could allow the parasite to be diagnosed without decreasing the number of critically endangered european eels through post-mortem. in the preliminary study, eels were examined with computed radiography, computed tomography, magnetic resonance imagi ...201625952716
anguillicola crassus infection significantly affects the silvering related modifications in steady state mrna levels in gas gland tissue of the european eel.using illumina sequencing, transcriptional changes occurring during silvering in swimbladder tissue of the european eel have been analyzed by comparison of yellow and silver eel tissue samples. functional annotation analysis based on go terms revealed significant expression changes in a number of genes related to the extracellular matrix, important for the control of gas permeability of the swimbladder, and to reactive oxygen species (ros) defense, important to cope with ros generated under hype ...201627242549
anguillicola crassus impairs the silvering-related enhancements of the ros defense capacity in swimbladder tissue of the european eel (anguilla anguilla).in a process called silvering, european eels prepare for their long-distance migration from european freshwater systems to the sargasso sea for reproduction. during this journey, eels perform extended diel vertical migrations, and the concomitant changes in hydrostatic pressure significantly affect the swimbladder, functioning as a buoyancy organ. as the swimbladder is primarily filled with oxygen, the tissue has to cope with extreme hyperoxic conditions, which typically are accompanied by the g ...201627146148
the hsp70 response of anguillicola species to host-specific stressors.the present study is based on infection experiments of two different swim bladder parasite species, anguillicola crassus kuwahara et al., 1974 and anguillicola novaezelandiae moravec and taraschewski, 1988, which were experimentally transferred to the two eel species anguilla anguilla linnaeus, 1758 and anguilla japonica temmink and schlegel, 1846, respectively. the host-parasite groups were selected due to their different grades of mutual adaptation. the main aim of this study was to analyze th ...201626920569
renal diuresis and antidiuresis after injections of arginine vasotocin in the freshwater eel (anguilla anguilla l.). 20164835434
myo-inositol phosphate synthase expression in the european eel (anguilla anguilla) and nile tilapia (oreochromis niloticus): effect of seawater acclimation.a single mips gene (isyna1/ino1) exists in eel and tilapia genomes with a single myo-d-inositol 3-phosphate synthase (mips) transcript identified in all eel tissues, although two mips spliced variants [termed mips(s) and mips(l)] are found in all tilapia tissues. the larger tilapia transcript [mips(l)] results from the inclusion of the 87-nucleotide intron between exons 5 and 6 in the genomic sequence. in most tilapia tissues, the mips(s) transcript exhibits much higher abundance (generally >10- ...201627252471
[chromatographic separation and determination of hormones of the oxytocin type (arginine-vasotocin and isotocin) from the pituitary and preoptic nucleus of the european eel (anguilla anguilla l.): eels from the baltic sea]. 20164982508
the capillary endothelium in the rete mirabile of the swimbladder of the eel (anguilla anguilla): functional and ultrastructural aspects. 20164854670
metabolic arrest and its regulation in anoxic eel hepatocytes.some vertebrates depress overall metabolism in an abrupt and reversible fashion when challenged with anoxia, ensuring stabilization of cellular [atp] and long-term survival, but little is known about the eliciting stimuli (e.g., change in o2, adenylates) and downstream effectors responsible for metabolic arrest. accordingly, eel (anguilla anguilla) hepatocytes were treated with inhibitors of putative components of the oxygen/metabolite-sensing pathway(s) and exposed to anoxia (po2=0 mmhg). anoxi ...201616228932
induction of dna strand breakage and apoptosis in the eel anguilla anguilla.the ability of benzo[a]pyrene, aroclor 1254, 2-3-7-8-tetrachlorodibenzo-p-dioxin and beta-naphthoflavone to induce dna strand breaks (sb) and apoptosis in erythrocytes of the european eel (anguilla anguilla) was investigated following by in vivo exposure. dna damage was evaluated by the comet assay, while the diffusion assay was used to investigate the induction of apoptosis 7 days after a single intraperitoneal administration. 2-3-7-8-tetrachlorodibenzo-p-dioxin induced the highest genotoxic ef ...201612408611
[isolation of neurosecretion granules from the preoptic nucleus and total hypophysis of the eel (anguilla anguilla l.) by ultracentrifugation]. 20166049264
[correlations between rheotropism and morphogenesis, on the one hand, and histologic structure of the endocrine pancreas, on the other hand, in the glass-eel (anguilla anguilla l.)]. 201614272355
laboratory and field-caging studies on hepatic enzymatic activities in european eel and rainbow trout.caging field experiments were conducted on young european eel (anguilla anguilla) and on rainbow trout (onchorynchus mykiss) for the determination of a biomonitoring protocol of freshwater streams. hepatic monooxygenase and conjugation enzyme activities were measured as biomarkers of exposure to some organic pollutants. laboratory studies were performed to compare the responsiveness of these two species concerning their enzymatic activities. the induction of monooxygenase activity, measured as t ...20159626548
preliminary investigations on vitellogenin m-rna induction in some bioindicator mediterranean fish species.this paper describes the development of a rt-pcr method for assaying vtg gene expression in different marine fish as a potentially valuable and sensitive biomarker of exposure to estrogenic chemicals. the levels of vtg mrna have been analyzed using primers specifically designed for the various species and the procedures have been standardized relative to actine mrna expression levels. different species were analyzed including organisms with a great potential as bioindicators in the mediterranean ...201512408634
the na+-k+-2cl- cotransporter and the osmotic stress response in a model salt transport epithelium.epithelia are physiologically exposed to osmotic stress resulting in alteration of cell volume in several aspects of their functioning; therefore, the activation of 'emergency' systems of rapid cell volume regulation is fundamental in their physiology. in this review, the physiological response to osmotic stress, particularly hypertonic stress, was described in a salt-transporting epithelium, the intestine of the euryhaline teleost european eel. this epithelium is physiologically exposed to chan ...201516734748
effects of high hydrostatic pressure on the pituitary-gonad axis in the european eel, anguilla anguilla (l.).european silver eels are thought to undergo sexual maturation during their oceanic reproductive migration from the european continent to their spawning area in the sargasso sea. tracking data and various anatomical and physiological features suggest that silver eels migrate in deep sea, leading us to hypothesise that high hydrostatic pressure (hp) influences the induction of eel reproduction. we subjected female and male silver eels to 101ata for 3 and 7 weeks, respectively, in a hyperbaric cham ...201517324430
metabolic and hematological studies on the yellow and silver phases of the european eel, anguilla anguilla l. iii. hematology. 20154452232
metabolic effects of technical pentachlorophenol (pcp) on the eel anguilla anguilla l. 20154653160
metabolic and hematological studies on the yellow and silver phases of the european eel, anguilla anguilla l. i. carbohydrate, lipid, protein and inorganic ion metabolism. 20154452230
effects of salinity, hypophysectomy and corticotrophin or branchial na- and k-activated atpase in the eel, anguilla anguilla l. 20154326155
enzyme activity patterns in white and red muscle of the eel (anguilla anguilla) at different developmental stages. 20154342454
influence of nematode anguillicoloides crassus infestation on the cellular and humoral innate immunity in european eel (anguilla anguilla l.).parasitic invasions are recognized as one of the primary factors responsible for decreasing populations of european eel. the aim of the present study was to determine the influence of infestation with the nematode anguillicoloides crassus on the innate immunity in european eel (anguilla anguilla). anguillicoloides crassus parasitizes the swim bladder of this fish. levels of the following immunological parameters were measured: spleen phagocyte respiratory burst activity, spleen phagocyte potenti ...201526557024
size does matter-a closer look on anguillicola morphology.the present study deals with morphological differences between two closely related parasitic nematode species (anguillicola crassus kuwahara et al., 1974 and anguillicola novaezelandiae moravec & taraschewski, 1988) in two different experimentally infected eel species (anguilla anguilla linnaeus, 1758 and anguilla japonica temminck & schlegel, 1847). furthermore, it considers the question whether size differences between those two species are ontogenetically determined or host species-dependent. ...201526096826
competing invaders: performance of two anguillicola species in lake bracciano.anguillicola crassus is one of the most successful parasitic invasive species as it has spread from its original habitat in east asia throughout the world and has acquired five new eel host species in the course of its invasion within the last three decades. records from an italian lake indicate that this species has even displaced an established population of its close relative a. novaezelandiae originating from new zealand. in order to analyze the reasons for its high invasive potential, this ...201525830111
relationship between european eel anguilla anguilla infection with non-native parasites and swimming behaviour on encountering accelerating flow.the effect of anguillicola crassus, pseudodactylogyrus bini and pseudodactylogyrus anguillae infection on the behaviour of downstream migrating adult european eels anguilla anguilla as they encountered accelerating water velocity, common at engineered structures where flow is constricted (e.g. weirs and bypass systems), was evaluated in an experimental flume. the probability of reacting to, and rejecting, the velocity gradient was positively related to a. crassus larval, adult and total abundanc ...201525801939
influence of adult anguillicoloides crassus load in european eels swimbladder on macrophage response.anguillicoloides crassus has become one of the most important threats to the european eel (anguilla anguilla). adult parasites colonize the swimbladder leading to an impaired functioning of this organ. the infection is also responsible for an increased in the stress level of infected eels, that could produce an altered immune response as well. differences in parasite loads and effects in the european and japanese eel (anguilla japonica) have been described. we have studied the influence of the n ...201525463301
richness and diversity of helminth species in eels from a hypersaline coastal lagoon, mar menor, south-east spain.the composition and diversity of parasite communities and intestinal components, as well as infra-community structure, were assessed in eels anguilla anguilla, from mar menor, a permanent mediterranean hypersaline coastal lagoon. data were used to determine whether this helminth community differs in composition and structure from that of eels in lagoons with lower salinity regimes and higher freshwater inputs. a total prevalence of 93% was detected. specifically, parasites were identified as der ...201524685015
duplicated leptin receptors in two species of eel bring new insights into the evolution of the leptin system in vertebrates.since its discovery in mammals as a key-hormone in reproduction and metabolism, leptin has been identified in an increasing number of tetrapods and teleosts. tetrapods possess only one leptin gene, while most teleosts possess two leptin genes, as a result of the teleost third whole genome duplication event (3r). leptin acts through a specific receptor (lepr). in the european and japanese eels, we identified two leptin genes, and for the first time in vertebrates, two lepr genes. synteny analyses ...201525946034
effect of the probiotic lactobacillus rhamnosus on the expression of genes involved in european eel spermatogenesis.positive effects of probiotics on fish reproduction have been reported in several species. in the present study, 40 male european eels were weekly treated with recombinant hcg for 9 weeks and with three different concentrations (10(3), 10(5), and 10(6) cfu/ml) of probiotic lactobacillus rhamnosus imc 501 (sinbyotec, italy). the probiotics were daily added to the water from the sixth week of the hcg treatment. males from the treated and control groups were sacrificed after 1, 2, and 3 weeks of pr ...201526271165
selection of best-performing reference gene products for investigating transcriptional regulation across silvering in the european eel (anguilla anguilla).the focus of the present study was to set a methodological approach for evaluating molecular mechanisms underlying silvering transformation in the european eel, anguilla anguilla. silvering is a tightly controlled process during which eels undergo significant morphological, physiological and behavioral changes, pre-adapting for the oceanic spawning migration. female eels showing different silver indexes were caught in different seasons in the comacchio lagoon (north adriatic sea, italy). isolate ...201526593703
transcriptomic profiling of male european eel (anguilla anguilla) livers at sexual maturity.the european eel anguilla anguilla has a complex life cycle that includes freshwater, seawater and morphologically distinct stages as well as two extreme long distance migrations. eels do not feed as they migrate across the atlantic to the sargasso sea but nevertheless reach sexual maturity before spawning. it is not yet clear how existing energy stores are used to reach the appropriate developmental state for reproduction. since the liver is involved in energy metabolism, protein biosynthesis a ...201526253995
subpopulation pattern of eel spermatozoa is affected by post-activation time, hormonal treatment and the thermal regimen.there has been a marked reduction in natural stocks of eels (genus anguilla) over the past 60 years, and the culture of eels is still based on the capture of very large quantities of juveniles. it is necessary to close the life cycle in captivity in order to ease the pressure on wild populations. the aims of the present study were to evaluate sperm subpopulations (through cluster analysis of computer-aided sperm analysis data) in the european eel (anguilla anguilla) and to assess the effects of ...201525402273
deep sequencing of the olfactory epithelium reveals specific chemosensory receptors are expressed at sexual maturity in the european eel anguilla anguilla.vertebrate genomes encode a diversity of g protein-coupled receptor (gpcr) that belong to large gene families and are used by olfactory systems to detect chemical cues found in the environment. it is not clear however, if individual receptors from these large gene families have evolved roles that are specific to certain life stages. here, we used deep sequencing to identify differentially expressed receptor transcripts in the olfactory epithelia (oe) of freshwater, seawater and sexually mature m ...201525580852
relationship between sperm quality parameters and the fatty acid composition of the muscle, liver and testis of european eel.this study looks at the correlations that fatty acids have with different tissues in the european eel (anguilla anguilla l.) during hormonally-induced sexual maturation, with different sperm quality parameters. in order to evaluate the different dynamics of the use of fatty acids, a categorization of the results from each sperm quality parameter (volume, concentration, motility and velocity) was performed. low and moderate correlations were observed between muscle tissue and some sperm quality p ...201525483240
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