standardization of european eel (anguilla anguilla) sperm motility evaluation by casa software.the development of powerful computer-assisted sperm analysis software has made kinetic studies of spermatozoa possible. this system has been used and validated for several species, but some technical questions have emerged regarding fish sample evaluations (i.e., frame rate, sperm dilution, chamber model, time of analysis, magnification lens, etc.). in the present study, we have evaluated the effects of different procedural and biological settings with the aim to correctly measure sperm quality ...201323465287
molecular characterization of three gnrh receptor paralogs in the european eel, anguilla anguilla: tissue-distribution and changes in transcript abundance during artificially induced sexual development.gonadotropin-releasing hormone receptor (gnrh-r) activation stimulates synthesis and release of gonadotropins in the vertebrate pituitary and also mediates other processes both in the brain and in peripheral tissues. to better understand the differential function of multiple gnrh-r paralogs, three gnrh-r genes (gnrhr1a, 1b, and 2) were isolated and characterized in the european eel. all three gnrhr genes were expressed in the brain and pituitary of pre-pubertal eels, and also in several peripher ...201323416230
tracking the migratory success of stocked european eels anguilla anguilla in the baltic investigate the extent to which european silver eels anguilla anguilla, originating from stocking programmes in the baltic sea tributaries, effectively contribute to the spawning stock, two hundred and seventy-four formerly stocked a. anguilla. emigrating from the schwentine river near kiel, germany, were tagged with t-bar anchor tags. a total of 29 anguilla spp. were recaptured (c. 11%) up to 14 months after release. stocking history of recaptured a. anguilla. was confirmed by otolith microc ...201323398076
temporal repeatability of metabolic rate and the effect of organ mass and enzyme activity on metabolism in european eel (anguilla anguilla).intraspecific variation in metabolic rate of fish can be pronounced and have been linked to various fitness-related behavioural and physiological traits, but the underlying causes for this variation have received far less attention than the consequences of it. in the present study we investigated whether european eels (anguilla anguilla) displayed temporal repeatability of body-mass-corrected (residual) metabolic rate over a two-month period and if variations in organ mass and enzyme activity be ...201323388212
environmental hazard of yperite released at sea: sublethal toxic effects on fish.the aim of this study was to evaluate the potential toxicological effects on fish related to the leakage of yperite from rusted bomb shells dumped at sea. both in vivo and field studies have been performed. as for the in vivo experiment, specimen of european eel were subcutaneously injected with 0.015, 0.15 and 1.5mg/kg of yperite and sacrificed after 24 and 48 h. in the field study, specimen of conger eel were collected from a dumping site in the southern adriatic sea. the presence/absence of y ...201323380450
new insights regarding gonad development in european eel: evidence for a direct ovarian european eel, it has been proposed that the undifferentiated gonad would develop into either an intersexual stage (syrski organ) or directly into an ovary. the syrski organ could then develop into either an ovary or a testis. in the present study, glass eels were raised until they reached a minimum size of 29 cm for histological sex assessment. in addition, some undifferentiated individuals with size encompassing 15-28 cm were sampled in a female-biased population (oir river). we also investi ...201323334566
reproduction of european eel and larval culture--state of the art. 201325141740
development of techniques and technology for embryonic and larval rearing of the european eel. 201325141622
proteomic responses of peripheral blood mononuclear cells in the european eel (anguilla anguilla) after perfluorooctane sulfonate exposure.since the 1980s, the stocks of european eel have been declining in most of their geographical distribution area. many factors can be attributed to this decline such as pollution by xenobiotics like perfluorooctane sulfonate (pfos). this study aimed at evaluating the in vitro toxicity of eel peripheral blood mononuclear cells (pbmc) exposed to pfos. exposure time and two concentrations were chosen to avoid cell mortality (48 h exposure at 10 μg pfos/l and 1mg pfos/l). after in vitro contamination ...201323261670
gene transcription reflects poor health status of resident european eel chronically exposed to environmental pollutants.understanding the effects of chronic exposure to pollutants on the genome and transcriptome of diadromous fish populations is crucial for their resilience under combined anthropogenic and environmental selective pressures. the catadromous european eel (anguilla anguilla l.) has suffered a dramatic decline in recruitment for three decades, necessitating a thorough assessment of the transcriptional effects of environmental pollutants on resident and migrating eels in natural systems. we investigat ...201323247545
catalasic activity in fish liver: improvement of the uv to visible analytic method.antioxidative defenses and more especially catalasic activity (cat) are studied in a large range of scientific research thematics. in environmental sciences, the problematic of oxidative stress is of great interest as pollutants can induce perturbations of redox homeostasis. consequently, changes in antioxidative defenses levels in fish tissues and particularly in liver are used as potential biomarkers of pollution. in most studies, the cat was assayed by following during 5 min the consumption o ...201323224832
multiple kisspeptin receptors in early osteichthyans provide new insights into the evolution of this receptor family.deorphanization of gpr54 receptor a decade ago led to the characterization of the kisspeptin receptor (kissr) in mammals and the discovery of its major role in the brain control of reproduction. while a single gene encodes for kissr in eutherian mammals including human, other vertebrates present a variable number of kissr genes, from none in birds, one or two in teleosts, to three in an amphibian, xenopus. in order to get more insight into the evolution of kissr gene family, we investigated the ...201223185286
spatial trends of organochlorinated pesticides, polychlorinated biphenyls, and polybrominated diphenyl ethers in atlantic anguillid eels.the bioaccumulation of lipophilic contaminants such as polychlorinated biphenyls (pcbs), organochlorine pesticides (ocps), and polybrominated diphenyl ethers (pbdes) can result in a reduction in fitness and spawner quality in eels and may be a factor in anguillid sp. population declines. contaminant concentrations in eels have been studied extensively in europe, but data for american eels are severely lacking. concentrations of pcbs, ocps, and pbdes were determined in american eel from eastern c ...201323168331
epr detection of paramagnetic chromium in liver of fish (anguilla anguilla) treated with dichromate(vi) and associated oxidative stress responses-contribution to elucidation of toxicity mechanisms.the impact of chromium (cr) on fish health has been the subject of numerous investigations, establishing a wide spectrum of toxicity, attributed particularly to the hexavalent form [cr(vi)]. however, reports on the simultaneous assessment of cr toxicity in fish and its toxico-kinetics, namely involving metal speciation, are scarce. therefore, keeping in view the understanding of the mechanisms of cr(vi) toxicity, this work intended to detect the formation of paramagnetic cr species in liver of a ...201323142145
effects of temperature on the nitric oxide-dependent modulation of the frank-starling mechanism: the fish heart as a case study.the frank-starling law is a fundamental property of the vertebrate myocardium which allows, when the end-diastolic volume increases, that the consequent stretch of the myocardial fibers generates a more forceful contraction. it has been shown that in the eel (anguilla anguilla) heart, nitric oxide (no) exerts a direct myocardial relaxant effect, increasing the sensitivity of the frank-starling response (garofalo et al., 2009). with the use of isolated working heart preparations, this study inves ...201323123761
unusual cases of adult intersexuality in the european eel anguilla anguilla.two cases of intersexuality are reported for the first time in european eel, anguilla anguilla (at the beginning of the silver eel stage), within 140 fish caught as glass eels in the south-west of france and reared in tanks at 17°c. cysts containing spermatozoa were observed in ovaries with pre-vitellogenic oocytes. this feature is very uncommon, especially owing to the fact that male cells do not normally reach this stage in captivity, and an environmentally controlled transdifferentation proce ...201223095260
topography and ultrastructure of the tegument of deropristis inflata molin, 1859 (digenea: deropristidae), a parasite of the european eel anguilla anguilla (osteichthyes: anguillidae).the tegumental ultrastructure of the intestine fluke deropristis inflata was studied using scanning and transmission electron microscopy. the surface of the tegument was covered by transverse cytoplasmic ridges from which protrude numerous thorn-like spines showing crenelated tips on the posterior part. spines were arranged in staggered rows. cobblestone-like units of the tegument were observed on a semicircle-shaped formation over the oral sucker. a tegumental excrescence was observed in the do ...201323052788
viral diseases of wild and farmed european eel anguilla anguilla with particular reference to the netherlands.diseases are an important cause of losses and decreased production rates in freshwater eel farming, and have been suggested to play a contributory role in the worldwide decline in wild freshwater eel stocks. three commonly detected pathogenic viruses of european eel anguilla anguilla are the aquabirnavirus eel virus european (eve), the rhabdovirus eel virus european x (evex), and the alloherpesvirus anguillid herpesvirus 1 (anghv1). in general, all 3 viruses cause a nonspecific haemorrhagic dise ...201223047193
surviving in a toxic world: transcriptomics and gene expression profiling in response to environmental pollution in the critically endangered european eel.genomic and transcriptomic approaches have the potential for unveiling the genome-wide response to environmental perturbations. the abundance of the catadromous european eel (anguilla anguilla) stock has been declining since the 1980s probably due to a combination of anthropogenic and climatic factors. in this paper, we explore the transcriptomic dynamics between individuals from high (river tiber, italy) and low pollution (lake bolsena, italy) environments, which were measured for 36 pcbs, seve ...201223009661
brominated flame retardants and dechloranes in eels from german rivers.the levels of pbdes, alternate bfrs and dechloranes in european eel (anguilla anguilla) samples (elvers, yellow and silver eels) were investigated to compare the contamination of eels from the rivers elbe and rhine and to estimate the bfr contamination throughout the eel's life cycle. pbdes were the dominating flame retardants (frs) in muscle tissues of yellow and silver eels, while the alternate bfr 2,3-dibromopropyl-2,4,6-tribromophenyl ether (dpte) and the dechlorane 602 were the dominating f ...201322985592
accumulation of mn, co, zn, rb, cd, sn, ba, sr, and pb in the otoliths and tissues of eel (anguilla anguilla) following long-term exposure in an estuarine environment.aiming at increasing the resolution of otolith tracers, we investigated the possibility to use mn, co, zn, rb, cd, sn, ba, sr, and pb otolith composition to retrieve the movements of eels (anguilla anguilla) in the lower gironde watershed. caging experiments were designed to validate the site specific otolith signatures. individually identified eels were reared in cages in three locations along the estuarine and river gradient. three trials were set up for successive periods of 3 months and 6 mo ...201222954653
polychlorinated dibenzodioxins, dibenzofurans, and biphenyls in fresh water fish from campania region, southern italy.twenty-eight fish muscle specimens from the main water bodies of the campania region were analyzed in our laboratory. on average, results showed a low contamination by pcdds+pcdfs and a relatively more important presence of dl-pcbs. all specimens were compliant with eu regulatory maximum levels. cumulative pcdd+pcdf+dl-pcb concentrations (teq(tot)) were comprised in the range 0.223-11.4 pgwho(97)-teq g(-1) fresh weight (fw). dl-pcb contribution to teq(tot) was on average greater than 86% (range, ...201322921647
diverse migration strategy between freshwater and seawater habitats in the freshwater eel genus anguilla.the freshwater eels of the genus anguilla, which are catadromous, migrate between freshwater growth habitats and offshore spawning areas. a number of recent studies, however, found examples of the temperate species anguilla anguilla, anguilla rostrata, anguilla japonica, anguilla australis and anguilla dieffenbachii that have never migrated into fresh water, spending their entire life history in the ocean. furthermore, those studies found an intermediate type between marine and freshwater reside ...201222803719
can a specialist parasite species of a widespread and common host species be rare? the case of spinitectus inermis (nematoda: cystidicolidae) in eels anguilla anguilla.the claim by many authors that spinitectus inermis (zeder, 1800), a narrowly specific parasite of european eels anguilla anguilla (l.), is a rare species is considered at three levels: its geographical range, its frequency of occurrence compared to other eel parasites and its relative abundance in component communities. the parasite is widely distributed in freshwater throughout the european range of the eel but its occurrence is erratic and unpredictable, being known from only 8 countries. surv ...201222779113
variations in the gene expression of zona pellucida proteins, zpb and zpc, in female european eel (anguilla anguilla) during induced sexual maturation.vertebrate eggs are surrounded by an extracellular glycoprotein coat termed zona pellucida (zp). integrity of zp is critical for a correct embryo development. two zona pellucida protein genes (zpb and zpc) from european eel were characterized, specific qpcr assays developed and their expression in immature males and females carried out. an experimental group of silver-stage eel females was maintained at 18 °c and hormonally induced to sexual maturation by weekly injections of carp pituitary extr ...201222750510
in vivo tracking of maturation in male european eel, anguilla anguilla (l.), by computed tomography.the present study aimed in vivo tracking of maturation of male eel by computed tomography (ct). additionally, individually monitored testes sizes were correlated with the conventionally used external maturity indicators (i.e. eye and nose indexes) in order to test and improve their usefulness at individual level. testes could be clearly identified with the ct from the end of the third week of hcg administration routinely used to induce maturation in fish. the volume of testes increased exponenti ...201222695518
fishery-induced selection for slow somatic growth in european eel.both theoretical and experimental studies have shown that fishing mortality can induce adaptive responses in body growth rates of fishes in the opposite direction of natural selection. we compared body growth rates in european eel (anguilla anguilla) from three mediterranean stocks subject to different fishing pressure. results are consistent with the hypotheses that i) fast-growing individuals are more likely to survive until sexual maturity than slow-growing ones under natural conditions (no f ...201222666373
evolution of microsatellite loci of tropical and temperate anguilla eels.anguilla eels are divided into temperate and tropical eels, based on their major distributions. the present study collected two temperate eels, anguilla japonica and anguilla anguilla, and two tropical eels, anguilla marmorata and anguilla bicolor pacifica, to examine two questions: do temperate and tropical anguilla eels have different genetic polymorphic patterns?; and do temperate anguilla japonica and anguilla anguilla have a closer relationship to each other than to tropical eels? in total, ...201222605978
the temperature challenges on cardiac performance in winter-quiescent and migration-stage eels anguilla anguilla.the present study was undertaken to examine cardiac responses to some of the temperature challenges that eels encounter in their natural environment. the contractile properties of ventricular muscle was studied on electrically paced tissue strips after long term acclimation at 0 °c, 10 °c, or 20 °c, and following acute ± 10 °c temperature changes. the time-course of contraction, and thus maximal attainable heart rates, was greatly influenced by working temperature, but was independent of acclima ...201222587961
quantitative bioassays for measuring biologically functional gonadotropins based on eel gonadotropic receptors.significant declines in eel stocks have been noted in many parts of the world. because eel aquaculture is dependent on wild-caught juveniles, there is a need to achieve artificial reproduction. adult eel maturation is currently induced by repeated injections of purified gonadotropin (human chorionic gonadotropin [hcg]) or pituitary extract. thus the determination of the biological efficacy and quantification of internal levels of gonadotropic hormones is important for optimizing artificial repro ...201222580328
genomics in eels--towards aquaculture and biology.freshwater eels (genus anguilla), especially the species inhabiting the temperate areas such as the european, american and japanese eels, are important aquaculture species. although artificial reproduction has been attempted since the 1930s and large numbers of studies have been conducted, it has not yet fully succeeded. problems in eel artificial breeding are highly diverse, for instance, lack of basic information about reproduction in nature, no appropriate food for larvae, high mortality, and ...201222527267
differential genotoxicity of roundup(®) formulation and its constituents in blood cells of fish (anguilla anguilla): considerations on chemical interactions and dna damaging has been widely recognized that pesticides represent a potential threat in aquatic ecosystems. however, the knowledge on the genotoxicity of pesticides to fish is still limited. moreover, genotoxic studies have been almost exclusively focused on the active ingredients, whereas the effect of adjuvants is frequently ignored. hence, the present study addressed the herbicide roundup®, evaluating the relative contribution of the active ingredient (glyphosate) and the surfactant (polyethoxylated am ...201222526921
development and validation of a range of endogenous controls to support the implementation of practical taqman real-time pcr-based surveillance for fish diseases within aquaculture.the use of taqman real-time pcr-based technology has recently become more frequent in the detection of pathogens in the aquaculture industry. this interest has necessitated the development of robust and reliable pathogen-detection assays. the development of a range of endogenous control assays to be run alongside these diagnostic assays works to further increase confidence in the latter. this study describes the design of a range of endogenous control assays based on the elongation factor 1-α (e ...201222524565
fish peripheral blood mononuclear cells preparation for future monitoring species possess many specific characteristics that support their use in ecotoxicology. widely used in clinical research, peripheral blood mononuclear cells (pbmcs) can reasonably be exploited as relevant target cells in the assessment of environmental chemical toxicity. the current article focuses on the methods necessary to isolate, characterize, and culture fish pbmcs. these procedures were successfully applied on an endangered species, the european eel (anguilla anguilla l.), and on an e ...201222497769
complete genomic sequence and taxonomic position of eel virus european x (evex), a rhabdovirus of european eel.eel virus european x (evex) was first isolated from diseased european eel anguilla anguilla in japan at the end of seventies. the virus was tentatively classified into the rhabdoviridae family on the basis of morphology and serological cross reactivity. this family of viruses is organized into six genera and currently comprises approximately 200 members, many of which are still unassigned because of the lack of molecular data. this work presents the morphological, biochemical and genetic charact ...201222401847
differential timing of gene expression regulation between leptocephali of the two anguilla eel species in the sargasso sea.the unique life-history characteristics of north atlantic catadromous eels have long intrigued evolutionary biologists, especially with respect to mechanisms that could explain their persistence as two ecologically very similar but reproductively and geographically distinct species. differential developmental schedules during young larval stages have commonly been hypothesized to represent such a key mechanism. we performed a comparative analysis of gene expression by means of microarray experim ...201122393514
primitive duplicate hox clusters in the european eel's genome.the enigmatic life cycle and elongated body of the european eel (anguilla anguilla l., 1758) have long motivated scientific enquiry. recently, eel research has gained in urgency, as the population has dwindled to the point of critical endangerment. we have assembled a draft genome in order to facilitate advances in all provinces of eel biology. here, we use the genome to investigate the eel's complement of the hox developmental transcription factors. we show that unlike any other teleost fish, t ...201222384188
comparative genomics reveals adaptive protein evolution and a possible cytonuclear incompatibility between european and american eels.during the early stages of speciation, interspecific gene flow may be impeded by deleterious epistatic interactions in hybrids, which maintain parental allelic combinations at the speciation genes. the resulting semipermeable nature of the barrier to interspecific gene flow provides a valuable framework to identify the genes involved in hybrid mortality or sterility, as well as the evolutionary mechanisms that initially caused their divergence. the two atlantic eels anguilla anguilla and a. rost ...201222362081
ultrastructural study of spermiogenesis and the spermatozoon of acanthocephaloides incrassatus (molin, 1858) (acanthocephala, paleacanthocephala, arhythmacanthidae) from anguilla anguilla (pisces, teleostei) in urbino ponds (corsica island).this study deals with first ultrastructure features of acanthocephaloides incrassatus (paleacanthocephala, arhythmacanthidae), a parasite of the fish anguilla anguilla, reported for the first time in a mediterranean pond. the spermiogenesis of a. incrassatus shows original specificities which have never been pointed out to this day in ultrastructural studies on spermiogenesis: the centriolar derivative is divided into two parts of different densities: an electron-dense, and the other, electron-l ...201222307764
fish welfare assurance system: initial steps to set up an effective tool to safeguard and monitor farmed fish welfare at a company level.the objective was to take a first step in the development of a process-oriented quality assurance (qa) system for monitoring and safeguarding of fish welfare at a company level. a process-oriented approach is focused on preventing hazards and involves establishment of critical steps in a process that requires careful control. the seven principles of the hazard analysis critical control points (haccp) concept were used as a framework to establish the qa system. haccp is an internationally agreed ...201222278705
do ocean-based wind farms alter the migration pattern in the endangered european silver eel (anguilla anguilla) due to noise disturbance? 201222278527
dna damage in fish (anguilla anguilla) exposed to a glyphosate-based herbicide -- elucidation of organ-specificity and the role of oxidative stress.organophosphate herbicides are among the most dangerous agrochemicals for the aquatic environment. in this context, roundup(®), a glyphosate-based herbicide, has been widely detected in natural water bodies, representing a potential threat to non-target organisms, namely fish. thus, the main goal of the present study was to evaluate the genotoxic potential of roundup(®) in the teleost fish anguilla anguilla, addressing the possible causative involvement of oxidative stress. fish were exposed to ...201222266476
the silvering process of european eel (anguilla anguilla) influences pah metabolite concentrations in bile fluid: consequences for monitoring.the stock of the catadromous european eel (anguilla anguilla l.) continues to decline and there is growing evidence that poor health status due to contaminants might be a key element in this decrease. organic contaminants such as polycyclic aromatic hydrocarbons (pahs) belong to the major threats to yellow eel in their growth habitat and their metabolites are detectable in the bile. starting the silvering process eels undergo physiological and morphological changes including cessation of feeding ...201222209300
biomonitoring of polychlorinated biphenyls (pcbs) in heavily polluted aquatic environment in different fish species.the distribution and concentrations of polychlorinated biphenyls (pcbs) were determined in fish species (european perch perca fluviatilis, northern pike esox lucius, pike perch sander lucioperca, wels catfish silirus glanus, common carp cyprinus carpio, european eel anguilla anguilla, freshwater bream abramis brama, goldfish carassius auratus, and roach rutilus rutilus) in a heavily polluted water reservoir zemplínska šírava (slovakia). the study performed at two different time points 5 years ap ...201222173787
changes in hormonal profile, gonads and sperm quality of argyrosomus regius (pisces, scianidae) during the first sexual differentiation and the present study, sexual gonadal differentiation and first sexual maturation of meagre (argyrosomus regius) was studied, based upon the annual changes in gonadosomatic index (gsi), gonadal histology, and the plasma steroid hormones, testosterone (t), 11-ketotestosterone (11-kt), and estradiol (e2). in addition, spermatozoa characteristics were evaluated by measuring sperm motility and morphology. results demonstrated that meagre completes sex differentiation at 10 to 12 mo of age, and are gr ...201222153261
molecular and biochemical biomarkers in environmental monitoring: a comparison of biotransformation and antioxidant defense systems in multiple tissues.the cytochrome p450 pathway and antioxidant responses are known for their responsiveness to environmental pollutants and are frequently used as biomarkers at the transcriptional, translational and catalytic levels. although molecular responses are often assumed to reflect similar changes in enzyme function, several factors can influence intracellular effects, including mrna stability and protein turnover, signal sensing and transduction, post-translational modifications of proteins, and multiple ...201122099345
induced oogenesis of the european eel (anguilla anguilla l.) in freshwater condition.european eel is a catadromous fish species, which means that after living in freshwater premature individuals adapt to sea water, and migrate to the sargasso sea for spawning. although male eel can be sexually matured even in freshwater, to date, it was believed that female eel can be matured only in seawater. here we show that the process of sexual maturation may be induced in freshwater by treating female eels with carp pituitary (gsi = 9.87 ± 1.55%). it is thus proposed that seawater conditio ...201122119876
myxosporean hyperparasites of gill monogeneans are basal to the multivalvulida.myxosporeans are known from aquatic annelids but parasitism of platyhelminths by myxosporeans has not been widely reported. hyperparasitism of gill monogeneans by myxidium giardi has been reported from the european eel and myxidium-like hyperparasites have also been observed during studies of gill monogeneans from malaysia and japan.the present study aimed to collect new hyperparasite material from malaysia for morphological and molecular descriptions. in addition, pcr screening of host fish was ...201122115202
topography and ultrastructure of the tegument of lecithochirium musculus (digenea: hemiuridae), a parasite of the european eel anguilla anguilla (osteichthyes: anguillidae).the tegumental ultrastructure of the stomach fluke lecithochirium musculus was studied using scanning and transmission electron microscopy. the surface of the tegument was smooth and covered by transverse cytoplasmic ridges. cobblestone-like units of the tegument were observed on the ventral surface. invagination and evagination of the ecsoma induced variations in the tegumental surface. the ultrastructural study revealed that the tegument of l. musculus had a typical syncytial organization with ...201222109611
a multidisciplinary weight of evidence approach for classifying polluted sediments: integrating sediment chemistry, bioavailability, biomarkers responses and bioassays.evaluation of chemical bioavailability and onset of biological alterations is fundamental to assess the hazard of environmental pollutants, particularly when associated to sediments which need to be removed. in the present work, five sediment samples were collected from the venice lagoon and data from sediment chemistry were integrated with those of bioaccumulation of chemicals in european eel (anguilla anguilla) exposed under laboratory conditions, responses of a wide battery of biomarkers, and ...201221982029
persistent organic pollutants (pops) in fish collected from the urban tract of the river tiber in rome (italy).european eel and chub samples were analyzed to determine the levels of non-dioxin-like polychlorobiphenyls (ndl-pcbs), polychlorodibenzodioxins (pcdds) and polychlorodibenzofurans (pcdfs), dioxin-like pcbs (dl-pcbs), and brominated polybromodiphenyl ethers (pbdes) in order to evaluate the extent of contamination of the river tiber along the urban tract through the city of rome (italy). all samples presented detectable levels of the chemicals analyzed, and exhibited species-specific differences i ...201121952158
influence of temperature regime on endocrine parameters and vitellogenesis during experimental maturation of european eel (anguilla anguilla) females.we examined the effect of temperature in european silver eels during their maturation induced by injections of carp pituitary extract on endocrine parameters: pituitary fshβ and lhβ expression, plasma 17β-estradiol (e2) and vitellogenin, estrogen receptor 1 (esr1), and vitellogenin 2 (vtg2) expression in liver. a variable thermal regime (t10) that increased from 10° to 14° and 17°c was compared with a constant 20°c regime (t20) during 12 weeks. t10 caused a faster development until week 8, highe ...201121871894
morphological and histochemical study of intestine in wild and reared european eel (anguilla anguilla l.).diet-related differences between the ratio of intestine length to body size and the enzymatic activity in the intestinal tract of wild and reared european eel (anguilla anguilla l.) were studied. compared with reared eel, wild eel showed significantly shorter relative intestine length. for the purpose of histochemical examination, different parts (anterior, middle and posterior) of intestine proper were used. activities of non-specific esterase, alkaline and acid phosphatase, and aminopeptidase ...201221818542
cholinesterase activities and sensitivity to pesticides in different tissues of silver european eel, anguilla anguilla.cholinesterase (che) activities were characterized in silver european eel, anguilla anguilla, grown in the brackish lagoon of comacchio (italy). all specimens were harvested at the "lavoriero", a traditional eel trapping weir that captures eels while leaving internal waters at the onset of reproductive migration. to our knowledge, no investigation on che was reported in silver eels. therefore a first characterization of enzyme activity in muscle, brain, liver and plasma of silver eel was carried ...201121777695
an integrated genetic-demographic model to unravel the origin of genetic structure in european eel (anguilla anguilla l.).the evolutionary enlightened management of species with complex life cycles often requires the development of mathematical models integrating demographic and genetic data. the genetic structure of the endangered european eel (anguilla anguilla l.) has been thoroughly analyzed in several studies in the past years. however, the interpretation of the key demographic and biologic processes that determine the observed spatio-temporal genetic structure has been very challenging owing to the complex li ...201125568002
metabolites of polycyclic aromatic hydrocarbons (pahs) in bile as biomarkers of pollution in european eel (anguilla anguilla) from german the light of the alarming decline of the european eel (anguilla anguilla l.) population, there is an urgent need to define ecological indicators for eel habitat quality. due to an increasing shortage of glass eels available for local stock enhancement, the decision of whether restocking is a valuable management tool to increase high-quality silver eel escapement to the sea needs to be evaluated. organic contaminants, such as polycyclic aromatic hydrocarbons (pahs), are among the major threats ...201221706228
pop up satellite tags impair swimming performance and energetics of the european eel (anguilla anguilla).pop-up satellite archival tags (psats) have recently been applied in attempts to follow the oceanic spawning migration of the european eel. psats are quite large, and in all likelihood their hydraulic drag constitutes an additional cost during swimming, which remains to be quantified, as does the potential implication for successful migration. silver eels (l(t) = 598.6±29 mm sd, n = 9) were subjected to swimming trials in a steffensen-type swim tunnel at increasing speeds of 0.3-0.9 body lengths ...201121687674
experimental quantification of the swimming performance and behaviour of spawning run river lamprey lampetra fluviatilis and european eel anguilla anguilla.using a large-scale open-channel flume, the swimming ability and behaviour of individual adult european eel anguilla anguilla and river lamprey lampetra fluviatilis, species that exhibit anguilliform locomotion, were quantified under complex hydraulic conditions created by a 0·2-0·3 m high under- or overshot weir during four discharge regimes. fishes were allowed to approach the weirs from both up- and downstream. all fishes passed the undershot weir, independent of discharge and direction of mo ...201121651544
dramatic effect of pop-up satellite tags on eel swimming.the journey of the european eel to the spawning area in the sargasso sea is still a mystery. several trials have been carried out to follow migrating eels with pop-up satellite tags (psats), without much success. as eels are very efficient swimmers, tags likely interfere with their high swimming efficiency. here we report a more than twofold increase in swimming cost caused by a regular small satellite tag. the impact was determined at a range of swimming speeds with and without tag in a 2-m swi ...201121594613
catadromous eels continue to be slippery research adults, atlantic eels (anguilla rostrata in the americas and anguilla anguilla in europe) are tubular slime-covered fish that spend most of their catadromous life-cycle in coastal environs before swimming far out to sea to reproduce, as part of an intergenerational migratory circuit that provides an interesting reversal of the pattern displayed by adult anadromous salmon that live mostly in the ocean but then migrate long distances to spawn in freshwater streams. earlier genetic findings on a ...201121544942
the use of eugenol and electro-narcosis as anaesthetics: transcriptional impacts on the european eel (anguilla anguilla l.).ecotoxicological studies aim to assess the potential environmental risks of various products. this implies the use of various biological models and tests on live animals. in case of handling fish and mammals, ethical rules have to be respected. the use of anaesthesia is considered to be the best way to ensure animal welfare. eugenol and electro-narcosis are among the most popular chemical and physical anaesthetics used in fisheries and by field biologists. in this study, the genetic and endocrin ...201121531020
heavy metals and organochlorinated compounds in the european eel (anguilla anguilla) from the adour estuary and associated wetlands (france).heavy metals and organic pollutants were investigated in the adour estuary (south west france) and associated wetlands using the european eel (anguilla anguilla) as a bioindicator. heavy metals (cu, cd, zn, pb, and ag) were measured in soft tissue of yellow eels. mercury (total hg and mehg) and organochlorinated compounds (7 pcbs, 11 ocps) were analysed in muscle. concentrations in muscle were in agreement with moderately contaminated environments in europe and were below the norms fixed for eel ...201121468402
fitness consequences of individual specialisation in resource use and trophic morphology in european eels.individual specialisation can lead to the exploitation of different trophic and habitat resources and the production of morphological variability within a population. although the ecological causes of this phenomenon are relatively well known, its consequences on individual fitness are less recognised. we have investigated the extent of individual specialisation in resource use and trophic morphology and its fitness consequences through a combination of tagging-recapture, stable isotope analyses ...201121455773
video tracking in the extreme: a new possibility for tracking nocturnal underwater transparent animals with fluorescent elastomer tags.initially developed so that an individual could be recognized in mark-recapture studies of aquatic animals, fluorescent visible implant elastomer (vie) tags are used here for a new application in ethometry: the study of the behavior of transparent animals in dim light or in darkness using automatic tracking technology. the application and validation of this multitracking method is tested in the context of research on the estuarine migratory behavior of the glass eel (anguilla anguilla), a crucia ...201121416308
first artificial hybrid of the eel species anguilla australis and anguilla anguilla.studies on artificial hybridization of different anguilla species were conducted recently, i.e. female a. australis with male a. dieffenbachii, and female a. japonica with male a. anguilla. the existence of these artificial hybrids was however not demonstrated by independent genetic methods. two species - a. anguilla and a. australis - that are phylogenetically close but have different sexual maturation times (12-25 weeks and 6-8 weeks, respectively), were expected to produce favourable hybrids ...201121396126
kinematics of swimming in two burrowing anguilliform fishes.anguilliform or eel-like fishes are typically bottom dwellers, some of which are specialized burrowers. although specializations for burrowing are predicted to affect the kinematics of swimming, it remains unknown to what extent this is actually the case. here we examine swimming kinematics and efficiency of two burrowing anguilliform species, pisodonophis boro and heteroconger hassi, with different degrees of specialization for burrowing. our data suggest that differences in the swimming kinema ...201121392954
the european eel quality database: towards a pan-european monitoring of eel quality.the stocks of the european eel anguilla anguilla are in decline and there is an increasing awareness that poor health status due to contaminants and/or diseases might be a key element in this decline and might be a hindrance to recovery. many countries have started compiling data on the health status of eels in their water bodies. objectives for these monitoring actions are diverse and there is a large amount of information collected by eu member countries. however, this information is widely sc ...201121374055
in vitro aerobic and anaerobic muscle capacities in the european eel, anguilla anguilla: effects of a swimming order to have a general view of metabolic requirements during swimming, in vitro aerobic and anaerobic fluxes were measured in red and white muscles from silver eels and yellow eels which differ in activity levels and nutritional states. these measurements were performed in control eels and after a 4 day swimming session (70% u(crit) in yellow eels, 80% u(crit) in silver eels). a swimming session significantly increases u(crit) from 12% to 18%, depending on the stage, with a significantly hig ...201121316488
all roads lead to home: panmixia of european eel in the sargasso sea.european eels (anguilla anguilla) spawn in the remote sargasso sea in partial sympatry with american eels (anguilla rostrata), and juveniles are transported more than 5000 km back to the european and north african coasts. the two species have been regarded as classic textbook examples of panmixia, each comprising a single, randomly mating population. however, several recent studies based on continental samples have found subtle, but significant, genetic differentiation, interpreted as geographic ...201121299662
prolonged feed deprivation does not permanently compromise digestive function in migrating european glass eels anguilla anguilla.the effects of prolonged feed deprivation (40 days at 18° c) and re-feeding (30 days) on body mass, growth and the activity of selected pancreatic and intestinal enzymes were evaluated in migrating european glass eels anguilla anguilla by comparison with a control group fed to satiation with hake merluccius merluccius roe for the duration of the experiment. feed deprivation resulted in mass loss and a reduction in digestive function, as revealed by a decrease in the total and specific activities ...201121284636
assessing sediment hazard through a weight of evidence approach with bioindicator organisms: a practical model to elaborate data from sediment chemistry, bioavailability, biomarkers and ecotoxicological bioassays.quality assessments are crucial to all activities related to removal and management of sediments. following a multidisciplinary, weight of evidence approach, a new model is presented here for comprehensive assessment of hazards associated to polluted sediments. the lines of evidence considered were sediment chemistry, assessment of bioavailability, sub-lethal effects on biomarkers, and ecotoxicological bioassays. a conceptual and software-assisted model was developed with logical flow-charts ela ...201121239037
the decline of the european eel anguilla anguilla: quantifying and managing escapement to support conservation.a method was developed to quantify the number and biomass of european eels anguilla anguilla escaping to the ocean for breeding. the non-intrusive method, involving a fixed-position, high-frequency multi-beam sonar, permitted constant surveillance of a. anguilla movements throughout their 5 month escapement season (july to december). during this period, >1000 individuals were monitored escaping to the atlantic ocean from their freshwater habitat in the river huntspill study site (somerset, u.k.) ...201121235544
[cdna cloning and tissue-differential expression of na+/k+/2cl(-)-cotransporter 1-alpha isoform in sarotherodon melanotheron].the gills are the major apparatus for osmoregulation in fish to acclimate the changes of salinities. na+/k+/2cl(-)cotransporter 1-alpha (nkcc1 alpha) is one of the key ion cotransporter locoalized in gill chloride cells which has been associated with the maintence of osmotic homeostasis. the transport process mediated by nkcc1 alpha is characterized by electroneutrality with a stoichiometry of 1na:1k:2cl. sarotherodon melanotheron is one of the most euryhaline teleosts able to withstand variatio ...201021174349
topography and ultrastructure of the tegument of bucephalus anguillae (digenea: bucephalidae), a parasite of the european eel anguilla anguilla (osteichthyen: anguillidae).the tegumental ultrastructure of the intestinal fluke bucephalus anguillae was studied with the use of scanning and transmission electron microscopy. the surface of the tegument is covered by transverse ridges from which protrude numerous closely packed, digitated, and claw-shaped spines. cobblestone-like units of the tegument were observed on the crescent-shaped formation of the rhynchus and at the posterior part of the body. three types of sensory structures were examined, i.e., 2 uniciliated ...201021158617
genetic patchiness in european eel adults evidenced by molecular genetics and population dynamics modelling.disentangling the demographic processes that determine the genetic structure of a given species is a fundamental question in conservation and management. in the present study, the population structure of the european eel was examined with a multidisciplinary approach combining the fields of molecular genetics and population dynamics modelling. first, we analyzed a total of 346 adult specimens of known age collected in three separate sample sites using a large panel of 22 est-linked microsatellit ...201121129491
development and validation of a two-step real-time rt-pcr for the detection of eel virus european x in european eel, anguilla anguilla.eel virus european x (evex) is one of the most common pathogenic viruses in farmed and wild european eel (anguilla anguilla) in the netherlands. the virus causes a hemorrhagic disease resulting in increased mortality rates. cell culture and antibody-based detection of evex are laborious and time consuming. therefore, a two-step real-time reverse transcriptase (rt-)pcr assay was developed for rapid detection of evex. primers and probe for the assay were designed based on a sequence of the rna pol ...201121126538
temperature dependency of element incorporation into european eel (anguilla anguilla) otoliths.the present study experimentally tested the influence of water temperature on the inclusion of 15 elements into juvenile european eel (anguilla anguilla) otoliths in freshwater. it should be investigated (1) if temperature effects on otolith sr/ca might impair the interpretation of migration studies and (2) if the elemental composition of otoliths can be used to reconstruct experienced temperature histories of eels. therefore, eels were kept under full experimental conditions at three different ...201121107822
determination of polybrominated diphenyl ethers in fish tissues by matrix solid-phase dispersion and gas chromatography coupled to triple quadrupole mass spectrometry: case study on european eel (anguilla anguilla) from mediterranean coastal lagoons.this paper describes the development and validation of an analytical methodology to determine 28 polybrominated diphenyl ethers (pbdes) in european eel (anguilla anguilla) tissues using matrix solid-phase dispersion (mspd) and gas chromatography coupled to triple quadrupole mass spectrometry (gc-qqq-ms/ms). a total of 28 pbdes were targeted, including tri- to deca-brominated congeners. the robustness and effectiveness of the proposed sample preparation procedure was demonstrated in lipid-rich ee ...201020800720
influence of oceanic factors on anguilla anguilla (l.) over the twentieth century in coastal habitats of the skagerrak, southern norway.the european eel (anguilla anguilla l.) is distributed in coastal and inland habitats all over europe, but spawns in the sargasso sea and is thus affected by both continental and oceanic factors. since the 1980s a steady decline has been observed in the recruitment of glass eels to freshwater and in total eel landings. the eel is considered as critically endangered on the international union for the conservation of nature and natural resources red list of species. the skagerrak beach seine surve ...201120798112
do otolith annular structures correspond to the first freshwater entry for yellow european eels anguilla anguilla in the baltic countries?to examine the relationship between freshwater entry and otolith annular structures, a total of 113 naturally recruited european eels anguilla anguilla from lithuania and latvia that entered fresh water at least once were collected. in some individuals (8.3-11.3%), the first freshwater entry coincided with a dark check that was distinctly different from neighbouring annuli. in most individuals (81.7-84.9%), the first freshwater entry occurred on rings and increments indistinguishable from other ...200920738518
cephalic morphology of pythonichthys macrurus (heterenchelyidae: anguilliformes): specializations for head-first burrowing.the heterenchelyidae, a family of anguilliformes, are highly specialized fossorial eels. this study was conducted to evaluate the cranial specialization in relation to head-first burrowing behavior in the heterenchelyid, pythonichthys macrurus. thereby, detailed descriptions are provided of the cranial myology and osteology of p. macrurus and its differences with that of representatives of three families: the moringuidae (moringua edwardsi), a head-first burrower; the anguillidae (anguilla angui ...201020730919
intra-specific scaling of natural mortality in fish: the paradigmatic case of the european eel.identifying factors and processes influencing natural mortality is fundamental to the understanding of population dynamics. metabolic theory of ecology and experimental studies at the cross-species level suggest the existence of general patterns linking natural mortality to body mass and temperature. however, there is scant evidence that similar relationships also hold at the intra-specific scale, possibly because of the relatively narrow range of sizes and temperatures experienced by most speci ...201120665048
european eel (anguilla anguilla) genotoxic and pro-oxidant responses following short-term exposure to roundup--a glyphosate-based herbicide.the glyphosate-based herbicide, roundup, is among the most used pesticides worldwide. due to its extensive use, it has been widely detected in aquatic ecosystems representing a potential threat to non-target organisms, including fish. despite the negative impact of this commercial formulation in fish, as described in literature, the scarcity of studies assessing its genotoxicity and underlying mechanisms is evident. therefore, as a novel approach, this study evaluated the genotoxic potential of ...201020643706
oceanic fronts in the sargasso sea control the early life and drift of atlantic eels.anguillid freshwater eels show remarkable life histories. in the atlantic, the european eel (anguilla anguilla) and american eel (anguilla rostrata) undertake extensive migrations to spawn in the oceanic sargasso sea, and subsequently the offspring drift to foraging areas in europe and north america, first as leaf-like leptocephali larvae that later metamorphose into glass eels. since recruitment of european and american glass eels has declined drastically during past decades, there is a strong ...201020573625
qualitative assessment of the diet of european eel larvae in the sargasso sea resolved by dna barcoding.european eels (anguilla anguilla) undertake spawning migrations of more than 5000 km from continental europe and north africa to frontal zones in the sargasso sea. subsequently, the larval offspring are advected by large-scale eastward ocean currents towards continental waters. however, the sargasso sea is oligotrophic, with generally low plankton biomass, and the feeding biology of eel larvae has so far remained a mystery, hampering understanding of this peculiar life history. dna barcoding of ...201020573615
a role for inositol monophosphatase 1 (impa1) in salinity adaptation in the euryhaline eel (anguilla anguilla).this study investigated the expression and tissue distribution of inositol monophosphatase (impa1) and characterized its role in salinity adaptation in the eel. the coding sequence of eel impa1 was determined and confirmed to be orthologous to the mammalian gene/enzyme by phylogenetic analysis and structural modeling. quantitative real-time pcr and western blot techniques indicated up to 17-fold increases in mrna expression and 2-fold increases in protein abundance in major osmoregulatory tissue ...201020547660
persistent organic pollutants (pcb, ddt, hch, hcb & bde) in eels (anguilla anguilla) in scotland: current levels and temporal trends.eels are an ideal biomonitor for persistent organic pollutants (pops) because of their high lipid content, longevity and tendency to remain within a defined range during their freshwater life phase. this study investigated concentrations of pops in eels (anguilla anguilla) from 30 sites across scotland, including polychlorinated biphenyls (pcbs), polybrominated diphenyl ethers (bdes), ddt (and metabolites), hexachlorocyclohexanes (alpha, beta, gamma-hch), hexachlorobenzene (hcb), hexachlorobutad ...201020471146
distribution of perfluorinated compounds in aquatic systems in the netherlands.the distribution of 15 perfluorinated compounds (pfcs) among eel (anguilla anguilla), sediment, and water was investigated for 21 locations in the netherlands. furthermore, for perfluorooctanesulfonate (pfos), a 30 year time series was measured for three locations using historical eel samples. these historical samples revealed concentrations increasing by a factor of 2-4 until the mid-1990s, followed by a return to the initial levels. in the samples described here, pfos dominated aqueous concent ...201020426438
swimming physiology of european silver eels (anguilla anguilla l.): energetic costs and effects on sexual maturation and reproduction.the european eel migrates 5,000-6,000 km to the sargasso sea to reproduce. because they venture into the ocean in a pre-pubertal state and reproduce after swimming for months, a strong interaction between swimming and sexual maturation is expected. many swimming trials have been performed in 22 swim tunnels to elucidate their performance and the impact on maturation. european eels are able to swim long distances at a cost of 10-12 mg fat/km which is 4-6 times more efficient than salmonids. the t ...201020390348
swimming suppresses hepatic vitellogenesis in european female silver eels as shown by expression of the estrogen receptor 1, vitellogenin1 and vitellogenin2 in the liver.when european silver eels (anguilla anguilla) venture into the atlantic ocean for their 6,000 km semelparous spawning run to the sargasso sea, they are still in a prepubertal stage. further sexual development appears to be blocked by dopaminergic inhibition of hypothalamus and pituitary activity. recently, we found that swimming for several weeks in freshwater stimulated the incorporation of fat droplets in the oocytes. so, it was hypothesized that long term swimming in seawater would release th ...201020302623
arsenic speciation in freshwater fish: focus on extraction and mass balance.arsenic (as) speciation in muscle tissues of freshwater fish was investigated with special emphasis on extraction yields and mass balances. for the quantification of water-soluble as compounds, samples were extracted using a 1:1 (v/v) methanol/water mixture. various extraction parameters, such as extraction volume, number of additional extractions, intermediate and final volume in sample preconcentration were optimized so as to improve the extraction efficiency. arsenic compounds were determined ...201020188911
thirty year monitoring of pcbs, organochlorine pesticides and tetrabromodiphenylether in eel from the netherlands.because of their excellent properties as a biomonitor, yellow eels (anguilla anguilla) have been used for time-trend monitoring of polychlorinated biphenyls (pcbs), organochlorine pesticides (ocps) and tetrabrominated diphenylether (tetra-bde). the program has now lasted for thirty years and has delivered valuable information on trends and spatial differences of these compounds in the delta of the rivers rhine and meuse and other dutch canals, rivers and lakes. specific local pcb, hch and dieldr ...201020185213
the occurrence of persistent chlorinated and brominated organic contaminants in the european eel (anguilla anguilla) in irish waters.the european eel (anguilla anguilla) is a relatively high lipid, long lived species capable of living in a variety of brackish, fresh and marine habitats. as such, eels can accumulate organic pollutants and have been incorporated into environmental monitoring programs as a suitable "bioindicator" species for the determination of the levels of organic contaminants within different water bodies. the global eel stock is now in decline and while the cause of the collapse remains unidentified, it is ...201020153504
identification of anguilla anguilla (l.) and anguilla rostrata (le sueur) and their hybrids based on a diagnostic single nucleotide polymorphism in nuclear 18s rdna.the variability of the nuclear 18s rdna was examined for 10 species of freshwater eels: anguilla anguilla, a. australis, a. dieffenbachii, a. japonica, a. marmorata, a. mossambica, a. nebulosa labiata, a. obscura, a. reinhardtii and a. rostrata. we observed that a single nucleotide polymorphism (snp) separated a. anguilla and a. japonica from the remaining taxa. while this snp marker may be used to identify hypothetical hybrids of a. japonica and sympatric eel species, we focused on atlantic eel ...201021565005
olfactory sensitivity to bile fluid and bile salts in the european eel (anguilla anguilla), goldfish (carassius auratus) and mozambique tilapia (oreochromis mossambicus) suggests a 'broad range' sensitivity not confined to those produced by conspecifics alone.teleosts have high olfactory sensitivity to bile salts. to assess whether this phenomenon is involved in intra-specific chemical communication alone, or is part of a more ;broad range' sensitivity to bile salts produced by heterospecifics, we investigated possible differences in the odour of bile between the sexes and among different species - the eel (anguilla anguilla), goldfish (carassius auratus) and mozambique tilapia (oreochromis mossambicus) - using the electro-olfactogram (eog). we also ...201020038666
developmental dynamics of cone photoreceptors in the eel.many fish alter their expressed visual pigments during development. the number of retinal opsins expressed and their type is normally related to the environment in which they live. eels are known to change the expression of their rod opsins as they mature, but might they also change the expression of their cone opsins?200920025774
reflex bradycardia does not influence oxygen consumption during hypoxia in the european eel (anguilla anguilla).most teleost fish reduce heart rate when exposed to acute hypoxia. this hypoxic bradycardia has been characterised for many fish species, but it remains uncertain whether this reflex contributes to the maintenance of oxygen uptake in hypoxia. here we describe the effects of inhibiting the bradycardia on oxygen consumption (mo(2)), standard metabolic rate (smr) and the critical oxygen partial pressure for regulation of smr in hypoxia (pcrit) in european eels anguilla anguilla (mean +/- sem mass 5 ...201020012057
the effects of contaminants in european eel: a review.european eel (anguilla anguilla (l.)) stocks are in decline in most of their geographical distribution and their status is considered below safe biological limits. recently, there is an increasing awareness that spawner quality might be an essential element in the decline of the species since pollution by bioaccumulating chemical substances may have a large impact on the reproduction success of the eel. this review gives an overview of the literature on the effects of contaminants on the europea ...201019806452
oceanic spawning migration of the european eel (anguilla anguilla).european eels (anguilla anguilla) undertake a approximately 5000-kilometer (km) spawning migration from europe to the sargasso sea. the larvae are transported back to european waters by the gulf stream and north atlantic drift. however, details of the spawning migration remain unknown because tracking eels in the atlantic ocean has, so far, eluded study. recent advances in satellite tracking enable investigation of migratory behavior of large ocean-dwelling animals. however, sizes of available t ...200919779192
temporal expression of hepatic estrogen receptor 1, vitellogenin1 and vitellogenin2 in european silver eels.because european silver eels have never been caught during or after their 6000-km reproductive migration to the sargasso sea, all existing knowledge on their sexual maturation comes from hormonal stimulation. silver eels that start their oceanic migration are still immature with pre-vitellogenic oocytes. hence we assumed that vitellogenesis should start with the expression of the estrogen receptor in the liver before the circulating 17beta-estradiol (e2) can have any effect. in this study we fol ...201019766647
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