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phospholamban s-nitrosylation modulates starling response in fish heart.the frank-starling mechanism is a fundamental property of the vertebrate heart, which allows the myocardium to respond to increased filling pressure with a more vigorous contraction of its lengthened fibres. in mammals, myocardial stretch increases cardiac nitric oxide (no) release from both vascular endothelium and cardiomyocytes. this facilitates myocardial relaxation and ventricular diastolic distensibility, thus influencing the frank-starling mechanism. in the in vitro working heart of the e ...200919726482
sex-related differences in aerobic capacities and reactive oxygen species metabolism in the silver eel.silver european eels (anguilla anguilla l.) need to develop important aerobic capacities to cope with their long fasting spawning migration at depth, particularly males which are about half the size of females. moreover, they have to face potential oxidative stress because reactive oxygen species (ros) production is linked to the increase in metabolic rate. thus, aerobic metabolism was globally evaluated in male and female silver eels exposed to a 10.1 mpa hydrostatic pressure (1,000 m depth). o ...201019680762
transcript profiling and dna damage in the european eel (anguilla anguilla l.) exposed to 7,12-dimethylbenz[a]anthracene.the molecular responses induced during and after an acute exposure to 7,12-dimethylbenz[a]anthracene (dmba) were analysed in liver, gill and blood cells of juvenile anguilla anguilla with the aim of developing molecular biomarkers of environmental pah pollution. changes in the mrna expression levels of the cell cycle checkpoint-related rad1 gene and the mrnas of differentially expressed genes by suppression subtractive hybridization (ssh) were analysed in the liver, and related to well-establish ...200919586669
brain derived neurotrophic factor and trk b mrna expression in the brain of a brain stem-spinal cord regenerating model, the european eel, after spinal cord injury.evidence from mammalian studies suggests that brain derived neurotrophic factor (bdnf) and its receptor, trk b, are upregulated in neuronal cell bodies after injury. although fish possess neurotrophins and display rapid functional and morphological recovery after central nervous system (cns) injury, to date few studies have examined neurotrophin expression during cns regeneration. in this study, rt-pcr was used to investigate the effect of complete spinal cord transection on the mrna expression ...200919545610
size selectivity of fyke nets for european eel anguilla anguilla.size selectivity of fyke nets for european eels anguilla anguilla was investigated by reviewing the results of published experimental studies. a general size selectivity model was then derived that can be easily incorporated into demographic models to simulate population dynamics, assess and monitor abundance and length structure of eel stocks and forecast the consequences of different management options.200920735696
route choices, migration speeds and daily migration activity of european silver eels anguilla anguilla in the river rhine, north-west europe.downstream migration of anguilla anguilla silver eels was studied in the lower rhine, germany, and the rhine delta, the netherlands, in 2004-2006. fish (n = 457) released near cologne with implanted transponders were tracked by remote telemetry at 12 fixed detection locations distributed along the different possible migration routes to the north sea. relatively more a. anguilla migrated via the waal than the nederrijn, as would be expected from the ratio of river discharges at the bifurcation po ...200920735693
effects of commercial fishing and predation by cormorants on the anguilla anguilla stock of a shallow eutrophic lake.mortality of eels anguilla anguilla in a large shallow lake in france due to predation by the cormorant phalacrocorax carbo was found to be moderate when compared to fishery catches over a 9 year period. the results show that, contrary to previous extrapolations made at the pan-european scale, p. carbo predation in shallow lakes is not invariably a major contributor to a. anguilla mortality, even in the presence of large colonies.200920735692
piscivory and trophic position of anguilla anguilla in two lakes: importance of macrozoobenthos density.the feeding habits of the european eel anguilla anguilla (>300 mm total length, l(t)) were compared in two lakes of different environmental state: lake grosser vätersee (lgv), germany (clear water, mesotrophic and submerged macrophytes), and lake vallum (lv), denmark (turbid, eutrophic and no submerged macrophytes). the density of macrozoobenthos was higher in lv (3500 individuals m(-2)) than in lgv (1500 individuals m(-2)). the abundance of small prey fishes (40-99 mm l(t)) was highest in lv. i ...200920735691
salinity-linked growth in anguillid eels and the paradox of temperate-zone catadromy.temperate-zone anguillid eels use both saline (marine or brackish) and fresh waters during their continental phase, but use of fresh waters is paradoxical because on average these fishes grow more rapidly in saline than in fresh waters. based on data from anguillid eels whose habitat-residency histories had been determined by sr:ca otolithometry, superiority of growth rates in saline water is much greater in american eels anguilla rostrata in north-eastern north america (mean saline:fresh growth ...200920735690
morphological and genetic seasonal dynamics of european eel anguilla anguilla recruitment in southern france.the fine scale morphological and genetic dynamics of successive waves of anguilla anguilla glass eel recruitment was studied over a 2 year period at a southern european mediterranean location (camargue, france) with continuous recruitment. using morphometric [total length (l(t)), mass (m), condition (k) and pigmentation stage] as well as genetic (allozyme) markers, the aim was to test for the existence of temporally separated spawning groups and explore the relation between genetic variability a ...200920735688
genetic composition of atlantic and mediterranean recruits of european eel anguilla anguilla based on est-linked microsatellite loci.anguilla anguilla glass eels arriving at two mediterranean and two atlantic sites were tested for differences in genetic composition between regions using a total of 23 microsatellite loci developed from an expressed sequence tag (est) library. hierarchical analysis of molecular variance indicated a non-significant difference between regions (mediterranean v. atlantic), which contrasted with the significant differences observed between samples within regions. the existence of a single spawning s ...200920735687
swimming activity and behaviour of european anguilla anguilla glass eels in response to photoperiod and flow reversal and the role of energy status.to better understand migratory divergences among anguilla anguilla glass eels, the behaviour of individuals caught at the time of their estuary entrance was studied through their response to a light:dark cycle and then to both water current reversal and light:dark cycle. in a first experiment, fish moving with the flow in response to dusk (m(+) fish) and fish that had not exhibited any movement (m(-) fish) were distinguished. anguilla anguilla from these two groups were then individually marked ...200920735685
environmental determinism of year-to-year recruitment variability of european eel anguilla anguilla in a small coastal catchment, the frémur river, north-west france.the influence of environmental factors (mainly the river flow) on the year-to-year variability of european eel anguilla anguilla fluvial recruitment in a small coastal catchment, the frémur river (north-west france) was examined. a comprehensive survey of catches from fixed traps at two weirs located at 4.5 km (pont es omnes dam) and 6.0 km (bois joli dam) above the river mouth was carried out between 1997 and 2004. young pigmented elvers (mean +/-s.d. total length, 133.7 +/- 29.6 mm) were recru ...200920735684
estimates of the mortality and the duration of the trans-atlantic migration of european eel anguilla anguilla leptocephali using a particle tracking model.using lagrangian simulations, based on circulation models over three different hydroclimatic periods in the last 45 years in the north atlantic ocean, the trans-atlantic migration of the european eel anguilla anguilla leptocephali was simulated via the passive drift of particles released in the spawning area. three different behaviours were modelled: drifting at fixed depth, undergoing a vertical migration or choosing the fastest currents. simulations included mortality hypotheses to estimate a ...200920735679
regulation of expression of the myo-inositol monophosphatase 1 gene in osmoregulatory tissues of the european eel anguilla anguilla after seawater acclimation.previous microarray studies in our laboratory identified a number of genes that were differentially expressed in "silver" eels after transfer from freshwater (fw) to seawater (sw). a group of genes, which are related to the synthesis, processing, and transport of certain known osmolytes in mammalian cells, have been identified. one gene implicated with osmolyte production is myo-inositol monophosphatase (impa1). the aim of this study was to compare the expression of impa1 in the major osmoregula ...200919456379
panmixia in european eel revisited: no genetic difference between maturing adults from southern and northern europe.previous studies of genetic structure in the european eel have resulted in seemingly conflicting results, ranging from no detectable heterogeneity to small but statistically significant differences and isolation by distance patterns among eels sampled across the continental range. differences with respect to sampling design and choice of molecular markers, combined with a lack of power estimates, complicate comparisons of existing results. in this study we have used six microsatellite markers an ...200919417764
magnetic particles associated with the lateral line of the european eel anguilla anguilla.magnetization measurements of the european eel anguilla anguilla demonstrated the presence of magnetic material concentrated in the region of the mandibular canals of the lateral line system. the data suggest that the material is magnetite, has a size suitable for magnetoreception and is of biogenic origin. the presence of magnetic particles in the lateral line system is discussed in relation to their possible role in allowing the fish to orientate with respect to the geomagnetic field during th ...200920735659
pcbs and the energy cost of migration in the european eel (anguilla anguilla l.).the effect of polychlorinated biphenyls (pcbs) on the energy consumption of fasting silver european eel (anguilla anguilla l.) was studied over a 27-day period during which the animals were at rest or were swimming 800 km in blazka swim tunnels. three-year-old female hatchery eels (silver stage) between 73 and 80 cm long weighing around 1 kg were dosed intraperitoneally with pcbs at a nominal dosage of 10x the consumption standard as a mixture representative for planar (7 microg pcb126/kg eel), ...200919371957
depth distribution and biological characteristics of the european eel anguilla anguilla in lough ennell, ireland.using a longline survey, a total of 196 european eels anguilla anguilla were collected at different depths in lough ennell (maximum depth 30 m), central ireland. the catch per unit of effort of a. anguilla that were caught from 1 to 25 m depths was lowest at 0.5-5.0 m and greatest at the deepest depth range (22.5-25.0 m). sub-samples of a. anguilla from depths of <15 m showed little or no difference in size, sex ratio, age, growth rate, condition factor, length-mass relationship, gonado-somatic ...200920735604
cortisol mobilizes mineral stores from vertebral skeleton in the european eel: an ancestral origin for glucocorticoid-induced osteoporosis?endogenous excess cortisol and glucocorticoid (gc) therapy are a major cause of secondary osteoporosis in humans. intense bone resorption can also be observed in other vertebrates such as migratory teleost fish at the time of reproductive migration and during fasting when large amounts of calcium and phosphate are required. using a primitive teleost, the european eel, as a model, we investigated whether cortisol could play an ancestral role in the induction of vertebral skeleton demineralization ...200919223398
isolation and characterization of expressed sequence tag-linked microsatellite loci for the european eel (anguilla anguilla).a european eel (anguilla anguilla) expressed sequence tag database consisting of 795 contigs and 4008 singletons was screened for microsatellites sequences. primers were designed to amplify 96 repeats, of which 86 gave good quality amplification products. twenty-eight microsatellites were selected for further microsatellite genotyping. only two loci were found to be monomorphic; out of the 26 polymorphic loci, number of alleles per locus ranged from two to 14, while the observed and expected het ...200921564612
growth and mortality of european glass eel anguilla anguilla marked with oxytetracycline and alizarin red.the growth and mortality of european glass eel anguilla anguilla 192 days after marking with oxytetracycline and alizarin red s were not significantly different between the two treatments and not different to the unmarked a. anguilla.200920735541
physiological responses to starvation in the european eel (anguilla anguilla): effects on haematological, biochemical, non-specific immune parameters and skin structures.the physiological effects of short-term starvation on some haematological, biochemical and non-specific immune response parameters together with the histological structure of the skin, were investigated in the european eel, anguilla anguilla. blood haemoglobin and haematocrit, serum glucose and cortisol, hemolysins, haemagglutinins, and lysozyme in the plasma, kidney and epidermal extract, were measured in fish after 31, 42 and 58 days of starvation, and compared to those of fed fish. starvation ...201019093221
guanylin-like peptides, guanylate cyclase and osmoregulation in the european eel (anguilla anguilla).three guanylin-like peptides, guanylin, uroguanylin and renoguanylin and two guanylate cyclase type c (gc-c) receptor isoforms were cloned and sequenced from the european eel (anguilla anguilla). all peptides and both receptors (gc-c1 and gc-c2) were predominantly expressed within the intestine and kidney of both sexually immature yellow, and sexually maturing, migratory silver eels. the derived amino acid sequences for the pre-prohormones and guanylate cyclase isoforms had structural features i ...200919028495
molecular cloning and characterization analysis of immunoglobulin m heavy chain gene in european eel (anguilla anguilla).in this study, the immunoglobulin m heavy chain gene of european eel (anguilla anguilla) was cloned and analyzed. the full-length cdna of the igm heavy chain gene (genbank accession no. ef062515) has 2089 nucleotides encoding a putative protein of 581 amino acids. the igm heavy chain was composed of leader peptide (l), variable domain (vh), ch1, ch2, hinge, ch3, ch4, and c-terminus and two novel continuous putative n-glycosylation sites were found close to the second cysteine of ch3 in a. anguil ...200919013650
two distinct dopamine d2 receptor genes in the european eel: molecular characterization, tissue-specific transcription, and regulation by sex steroids.two full-length cdna encoding putative dopamine d2-like receptors were cloned from the brain of female european eel. the deduced protein sequences, termed d2a- and d2b-r, exhibit closer phylogenetic relationships to vertebrate d2 receptors compared with d3 and d4 or d1 receptors. the two protein sequences share 100% identity within the transmembrane domains containing the highly conserved amino acids involved in dopamine binding. accordingly, an apparent single population of sites on eel brain m ...200918974275
effects of propanil on the european eel anguilla anguilla and post-exposure recovery using selected biomarkers as effect criteria.the aim of this study was to assess the physiological response of anguilla anguilla to propanil and the degree of recovery after being moved to clean water. preliminary acute toxicity test was carried out in the laboratory and the median lethal concentration (lc50) at 96 h was calculated as 31.33 mg/l (29.60-33.59 mg/l). noec and loec values (at 96 h) were also calculated as 20 and 25mg/l, respectively. the fish were exposed to 0.63 and 3.16 mg/l of propanil for 72 h and allowed to recover for 1 ...200918973941
isolation and characterization of 12 dinucleotide microsatellites in the european eel, anguilla anguilla l., and tests of amplification in other species of eels.twelve polymorphic dinucelotide microsatellites in the freshwater eel anguilla anguilla l. were isolated and characterized. genetic diversity was assessed in eels from lake constance, germany. allele numbers ranged from five to 26 per locus with observed heterozygosities between 0.125 and 0.875. a portion of locus aangct77 aligns with a transcribed region of the zebrafish gene crystallin beta b2. cross-species amplification of most markers was possible for nine other anguilla eel species. the ne ...200821586052
the inflammatory response of fish to helminth parasites.fish serve as a good model for studying vertebrate immune systems because they have a relatively simple system. descriptions of histopathological effects of helminth parasites on fish are few and far between with limited observations made on the identification of the inflammatory cells involved in the host reaction. recently, two cell types found within teleosts received a great deal of attention, namely mast cells and rodlet cells. fish most cells also known as eosinophilic granule cells, are m ...200818814717
glycolytic fluxes in european silver eel, anguilla anguilla: sex differences and temperature sensitivity.european silver eels migrate 6000 km to their supposed spawning area in the sargasso sea. as the eel is fasting, this intense swimming activity is realised only with fat stores, involving mainly red muscle i.e. aerobic metabolism. however, eel migration is performed at depth and thus in cold water, both being known to induce changes in muscle energy metabolism. during migration, white and red muscles can operate together or separately in order to counteract the eventual effects of low temperatur ...200818789394
ammonia sensitivity of the glass eel (anguilla anguilla l.): salinity dependence and the role of branchial sodium/potassium adenosine triphosphatase.eel aquaculture is capture based and thus dependent on the fishery for juvenile glass eels. this fishery typically takes place in estuaries where salinity varies and ammonia levels can be elevated. also, during capture and transport glass eels are kept at high densities and ammonia from endogenous production can increase to toxic levels. ammonia is known to have detrimental effects on fish growth and survival. in the present study, the salinity dependence of ammonia sensitivity in glass eels acc ...200918717620
the suitability of cytochrome-p4501a1 as a biomarker for pcb contamination in european eel (anguilla anguilla).european eel (anguilla anguilla) elvers were intraperitoneally injected with different doses of 3,3',4,4'-tetrachlorobiyphenyl (pcb77) to examine and characterize the inductive effect of coplanar pcbs on cyp1a1 gene expression in liver and gills by using a semi-quantitative rt-pcr analysis. the influence of pcb77 injection on transcription activity of the housekeeping gene glyceraldehyde-3-phosphate-dehydrogenase (gapdh) was tested to determine its suitability as a reference gene for further qua ...200818657580
how cadmium could compromise the completion of the european eel's reproductive migration.the european eel (anguilla anguilla l.) is severely threatened with extinction. surprisingly, even though their unusual life cycle makes them particularly vulnerable to pollution, the possible contribution of contamination remains especially poorly known. here we have investigated the possible effect of cadmium (cd), a widespread nonessential metal, on eel reproductive capacities. both control and cd precontaminated female silver eels were experimentally matured and forced to swim in metal-free ...200818605594
cost of transport and optimal swimming speed in farmed and wild european silver eels (anguilla anguilla).a swimming speed of 0.4 meters per second (m s(-1)) is the minimal speed for european female silver eels to reach the spawning sites in the sargasso sea in time. as silver eels cease feeding when they start their oceanic migration, the cost of transport (cot) should be minimised and the swimming speed optimised to attain the highest energetic efficiency. in this study, we have investigated the optimal swimming speed (u(opt)) of silver eels since u(opt) may be higher than the minimal swimming spe ...200818599333
interactions of 2,4,6-trinitrotoluene (tnt) with xenobiotic biotransformation system in european eel anguilla anguilla (linnaeus, 1758).the aim of the present study was to investigate the interaction of 2,4,6-trinitrotoluene (tnt) with liver biotransformation enzymes in european eel anguilla anguilla (linnaeus, 1758). eels were exposed to 0.5, 1 and 2.5mg/l nominal concentrations of tnt for 6 and 24h. modulation of cyp1a1, udpgt and gst genes was investigated by real-time pcr. total cyp450 content, nadph cytochrome c reductase activity, cyp1a and cyp2b-like activities, such as erod, mrod and brod, as well as gst and udpgt activi ...200818407354
effects of 2,4,6-trinitrotoluene (tnt) on phase i and phase ii biotransformation enzymes in european eel anguilla anguilla (linnaeus, 1758).the aim of this study was to investigate effects of the explosive 2,4,6-trinitrotoluene (tnt) on liver drug metabolizing genes and enzymes in the european eel anguilla anguilla as a model fish species. eels were exposed in vivo for 6h and 24h to 0.5, 1 and 2.5mg/l nominal concentrations of tnt. expression of cyp1a, glutathione-s-transferase (pi-class; gst) and uridine-diphosphate glucuronosyltransferase (1-family) (udpgt) genes was investigated by rt-pcr, and 7-ethoxy- and 7-methoxyresorufin-o-d ...200818378298
pressure and temperature interactions on aerobic metabolism in migrating silver eels: results in vitro.the european eel (anguilla anguilla) migrates (6000 km) from european coast towards the supposed spawning area: the sargasso sea. this intensive and sustained swimming activity is performed without feeding and by using essentially red muscle i.e. aerobic metabolism. temperature and hydrostatic pressure vary during migration and have known effects on energy metabolism, mainly on mitochondrial functioning. we raise the question about the existence of a pressure-temperature combination that optimiz ...200818351124
is cl- protection against silver toxicity due to chemical speciation?in freshwater teleosts, the primary mechanism of acute silver toxicity is inhibition of na(+)/k(+) atpase and carbonic anhydrase at the gill, leading to net na(+) and cl(-) loss due to the continued diffusion of these ions into the hypoosmotic external environment. external cl(-) has been shown to protect rainbow trout (oncorhychus mykiss) against silver toxicity presumably by complexation to form agcl. however, cl(-) does not appear to greatly influence silver toxicity to at least two other spe ...200818304659
modulatory role of copper on β-naphthoflavone-induced dna damage in european eel (anguilla anguilla l.).gill and kidney dna integrity (alkaline unwinding assay) was assessed in anguilla anguilla exposed for 24-h to copper (cu: 1 or 2.5 μm), with or without 24-h pre-exposure to a polycyclic aromatic hydrocarbon (pah)-like compound--β-naphthoflavone (bnf: 2.7 μm). gill showed dna integrity loss in all the exposure conditions, reflecting a dual mode of bnf-cu interaction depending on the metal concentration. thus, antagonistic or additive effects were observed for bnf+cu 1 μm or bnf+cu 2.5 μm, respec ...200818304634
a field survey of metal binding to metallothionein and other cytosolic ligands in liver of eels using an on-line isotope dilution method in combination with size exclusion (se) high pressure liquid chromatography (hplc) coupled to inductively coupled plasma time-of-flight mass spectrometry (icp-tofms).the effect of metal exposure on the accumulation and cytosolic speciation of metals in livers of wild populations of european eel with special emphasis on metallothioneins (mt) was studied. four sampling sites in flanders showing different degrees of heavy metal contamination were selected for this purpose. an on-line isotope dilution method in combination with size exclusion (se) high pressure liquid chromatography (hplc) coupled to inductively coupled plasma time-of-flight mass spectrometry (i ...200818302969
first observations of histopathological effects of 2,4,6-trinitrotoluene (tnt) in gills of european eel anguilla anguilla (linnaeus, 1758): histopathological effects of 2,4,6-trinitrotoluene in gills of european eel.the aim of the present study was to investigate the effects on gill morphology of the explosive 2,4,6-trinitrotoluene (tnt) in a model fish, the european eel, anguilla anguilla (linnaeus, 1758) to assess potential detrimental effects in marine fish due to its presence in dumping areas. juvenile specimens of a. anguilla were exposed in vivo for 6 and 24 h to 0.5, 1 and 2.5 mg/l nominal concentrations of tnt using dimethyl sulfoxide (0.1 per thousand) as solvent carrier. histological analysis of g ...200818297406
offshore windmills and the effects of electromagnetic fields on fish.with the large scale developments of offshore windpower the number of underwater electric cables is increasing with various technologies applied. a wind farm is associated with different types of cables used for intraturbine, array-to-transformer, and transformer-to-shore transmissions. as the electric currents in submarine cables induce electromagnetic fields there is a concern of how they may influence fishes. studies have shown that there are fish species that are magneto-sensitive using geom ...200718240676
relationships between locomotor behavior, morphometric characters and thyroid hormone levels give evidence of stage-dependent mechanisms in european eel upstream migration.in order to decipher movements during freshwater eel colonization, we experimentally characterized individual locomotor behavior of two eel life history stages: elvers and yellow eels. a ramp located at the flume tank upstream side required a specific locomotor behavior to be ascended. placing individually tagged eels in the middle of the tank three times successively tested behavioral consistency. eels climbing the ramp on each trial were classified as "upstream climbers" whereas eels settling ...200817950736
differential expression of absorptive cation-chloride-cotransporters in the intestinal and renal tissues of the european eel (anguilla anguilla).duplicate pairs of isoforms of each of the nkcc2 and the ncc absorptive cation-chloride-cotransporters have been isolated from the european eel. as with mammalian nkcc2, nkcc2alpha isoform mrna expression was restricted to renal tissues, whereas nkcc2beta isoform expression was present in intestine and urinary bladder. similar to mammalian ncc, nccalpha mrna expression was also found in the kidney, whereas, expression of nccbeta mrna was found at low levels in a number of tissues but particularl ...200817950642
probabilistic approach to polychlorinated biphenyl (pcb) exposure through eel consumption in recreational fishermen vs. the general population.concentrations of the sum of the seven indicator pcbs (sigma7 ipcbs) measured in non-commercial european eel (anguilla anguilla l.) in flanders are high: in 80% of all sampled localities, the belgian pcb standard for fish was exceeded. the objective of this study was to assess the intake of the sigma7 ipcbs through consumption of eel by recreational fishermen and to compare it to the intake of a background population. the median estimated intake for recreational fishermen varied between 18.4 and ...200717852389
transcriptomic approach to the study of osmoregulation in the european eel anguilla anguilla.in euryhaline teleosts, osmoregulation is a fundamental and dynamic process that is essential for the maintenance of ion and water balance, especially when fish migrate between fresh water (fw) and sea water (sw) environments. the european eel has proved to be an excellent model species to study the molecular and physiological adaptations associated with this osmoregulatory plasticity. the life cycle of the european eel includes two migratory periods, the second being the migration of fw eels ba ...200717666525
nitric oxide modulates ionic transport in the isolated intestine of the eel, anguilla anguilla.we investigated the role of no (nitric oxide) in the isolated intestine of the sea water adapted eel, by testing the effect of various donors on i(sc) (short-circuit current), due to net cl(-) absorption in the control conditions. we found that the endogenous no-synthase substrate l-arginine as well as two different no donors, snp (sodium nitroprusside) and sin-1 (3-morpholinosydnonimine), produced a slow and gradual decrease of i(sc). the effect of snp was reduced by the pretreatment with odq ( ...200717604669
energy and migratory behavior in glass eels (anguilla anguilla).the influence of energy content of glass eels (anguilla anguilla) on their migratory behavior was investigated in november 2004 and february 2005 under laboratory conditions. fish were sorted according to their response to a decrease in light intensity: glass eels becoming active at dusk and using water flow to move with the current were considered as "active", whereas those remaining in the substratum throughout the catching period (24 h) were categorized as "inactive". "active" glass eels exhi ...200717561177
to what extent are hepatic concentrations of heavy metals in anguilla anguilla at a site in a contaminated estuary related to body size and age and reflected in the metallothionein concentrations?we explored how hepatic [metal]s in anguilla anguilla at a contaminated estuarine site are influenced by body size, age and season, and the extent that [cu], [cd] and [zn]s are reflected in [metallothionein (mt)]s. although each [metal] and [mt] increased significantly with length, weight and age, those biotic variables explained <10% of the variation in each [metal] and only 11-16% for [mt]. seasonal changes in [cu] and [cd] were paralleled by [mt]. the variation in [mt] explained by cu (42%) w ...200817548139
common pattern of gene expression in response to hypoxia or cadmium in the gills of the european glass eel (anguilla anguilla).european eel (anguilla anguilla) populations are in decline. glass eel recruitment has fallen 10-fold since the early 1980s. estuaries play a fundamental role in the life history of eels because glass eels must pass through them to reach freshwater ecosystems. unfortunately, because of their geographical position at the upstream basin slopes, estuaries accumulate metals like cadmium and are important sites of hypoxia events. in this context, we studied the effect of the oxygen level on the venti ...200717533871
spermiogenesis and sperm ultrastructure of deropristis inflata molin, 1859 (digenea, deropristidae), a parasite of anguilla anguilla.to our knowledge, this paper describes the first ultrastructural results on spermiogenesis and the spermatozoon of a digenea belonging to the family deropristidae, deropristis inflata. spermiogenesis follows the usual pattern found in the digeneans, but a single noteworthy characteristic concerns the centriole, which presents a "prominent pear-shaped electron-dense region." spermiogenesis in d. inflata begins with the formation of a differentiation zone. the two centrioles give rise to flagella. ...200717484073
does a 5500-km swim trial stimulate early sexual maturation in the european eel (anguilla anguilla l.)?the catadromous european eel (anguilla anguilla l.) undertakes a 6000-km spawning migration from its freshwater habitats to the sargasso sea. in large blazka swim tunnels of 127 l, the physiological effect of such a prolonged swimming performance on sexual maturation in adult female eels was investigated. two groups of eels were placed in swim tunnels for 173 days, one group was able to swim at 0.5 body lengths/second (swim group) covering a distance of c. 5500-km over the experimental period, a ...200717451986
environmental stress and life-stage dependence on the detection of heterozygosity-fitness correlations in the european eel, anguilla anguilla.heterozygosity-fitness correlations (hfcs) have been reported in populations of many species, although hfcs can clearly vary across species, conspecific populations, temporal samples, and sexes. we studied (i) the temporal stability of the association between genetic variation and growth rate (length and mass increase) and (ii) the influence of genetic variability on survival in the european eel (anguilla anguilla l). hfcs were assessed using genotypes from 10 allozyme and 6 microsatellite marke ...200617426758
development of real-time rt-pcr assays for eel gonadotropins and their application to the comparison of in vivo and in vitro effects of sex steroids.gonadotropins, luteinizing hormone (lh) and follicle-stimulating hormone (fsh), are key factors in the brain-pituitary-gonad axis and understanding their regulation remains essential for future management of eel reproduction. in this regard, we developed quantitative real-time rt-pcr (qrtrt-pcr) assays for the expression of european eel lhbeta, fshbeta and gpalpha subunits, using the light cycler system. the qrtrt-pcr was adapted to permit detection of the three gonadotropin subunit mrnas in ind ...200917418843
a preliminary observation on the pond culture of european eel, anguilla anguilla (linnaeus, 1758) in egypt: recommendations for future studies.an experiment was conducted to assess the potential of the european eel, anguilla anguilla for earthen pond aquaculture without supplementary feeding at lake manzala, egypt. juvenile a. anguilla of mean length 11.7 cm and 2.4 g weight were stocked in earthen ponds measuring 3 feddans (about 12,600 m2) and 1 m deep. stocking was done in may 2003 at a rate of 5000 fish feddan(-1) in a polyculture system including tilapia and mullets and fed mainly on natural occurring prey (natural spawned tilapia ...200719070049
cortisol regulates eel (anguilla anguilla) aquaporin 3 (aqp3) mrna expression levels in gill.previous studies in eel (anguilla anguilla) gill have shown that the expression of the aquaporin 3 (aqp3) water and small solute channel is dramatically decreased (mrna abundance decreased by up to 97%) when these euryhaline fish are acclimated from freshwater (fw) to seawater (sw). however, aqp3 mrna expression levels in the intestine following sw-acclimation do not change. the sw-acclimating corticosteroid hormone, cortisol has previously been shown to regulate the expression of aquaporins (pa ...201317353012
effect of sperm cryopreservation on the european eel sperm viability and spermatozoa morphology.the main objective of the present work was to study the effect of cryopreservation of european eel sperm both on the sperm viability and the spermatozoa head morphology. spermatozoa morphology was evaluated with computer-assisted morphology analysis after collection in fresh samples, after adding the freezing medium containing dimethyl sulfoxide as cryoprotectant and, finally, after the cryopreservation process and thawing. cell viability was assessed, in both fresh and thawed samples, by hoechs ...200717348973
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
salinity adaptation and gene profiling analysis in the european eel (anguilla anguilla) using microarray technology.the life cycle of the european eel (anguilla anguilla) includes two long migratory periods, when the newly hatched leptocephali larvae drift on ocean currents from the sargasso sea to the shores of western europe and then again up to 30 years later when adult eels swim back to their place of birth for reproductive purposes. prior to the migration from fresh water (fw) to sea water (sw) adult yellow eels undergo various anatomical and physiological adaptations (silvering) which promote sexual dev ...200717324422
the role of volume-sensitive ion transport systems in regulation of epithelial transport.this review focuses on using the knowledge on volume-sensitive transport systems in ehrlich ascites tumour cells and nih-3t3 cells to elucidate osmotic regulation of salt transport in epithelia. using the intestine of the european eel (anguilla anguilla) (an absorptive epithelium of the type described in the renal cortex thick ascending limb (ctal)) we have focused on the role of swelling-activated k+- and anion-conductive pathways in response to hypotonicity, and on the role of the apical (lumi ...200717289411
impairment of lipid storage by cadmium in the european eel (anguilla anguilla).because european silver eels (anguilla anguilla) fast during their reproductive migration to the sargasso sea, the successful completion of their unusual life cycle depends on quantity of lipids stored beforehand. these lipids are mainly accumulated during the growth phase stage of the animals, called yellow eel, as triglycerides in muscle. they are then catabolized to provide sufficient energy to enable migration, gonad maturation and spawning. in the laboratory, we investigated the possible im ...200717276523
stocking density at early developmental stages affects growth and sex ratio in the european eel (anguilla anguilla).to investigate the effect of stocking density on growth and sex ratio in european eel, four constant density conditions were tested during the transition from the glass to the elver stage for 90 days (period 1). the test conditions combined the weight of fish per unit surface or volume (surface density or volume density) resulting in four experimental groups: low surface density (0.5 kg/m(2)) and low volume density (5 kg/m(3)) (group s(0.5)v(5)); low surface density (0.5 kg/m(2)) and high volume ...200617179387
beta3-adrenoceptor in the eel (anguilla anguilla) heart: negative inotropy and no-cgmp-dependent mechanism.neuroendocrine regulation of cardiac function involves a population of three types of beta-adrenoceptors (ars). in various mammalian species, beta1- and beta2-ar stimulation produces an increase in contractility; whereas beta3-ar activation mediates negative inotropic effects. at the moment, nothing is known about the physiological role of beta3-ar in fish. using an isolated working heart preparation, we show that a beta3-ar selective agonist brl(37344) (0.1-100 nmol l(-1)) elicits a dose-depend ...200617142685
the involvement of cytochrome p450 system in the fate of 2,4,6-trinitrotoluene (tnt) in european eel [anguilla anguilla (linnaeus, 1758)].tnt (2,4,6-trinitrotoluene) was the most common nitro aromatic explosive available in world war ii ammunitions. the presence of ordnance dumped at sea might represent a great concern for marine species living close to dumping sites and the toxicological properties of the chemicals released into the marine environments need to be evaluated. the aim of the present study is to investigate the involvement of cyp (cytochrome p450) system in the metabolism of tnt in marine organisms by using the europ ...200617073791
crucial role of cytoskeleton reorganization in the negative inotropic effect of chromogranin a-derived peptides in eel and frog hearts.vasostatins (vss), i.e. the main biologically active peptides generated by the proteolytic processing of chromogranin a (cga) n-terminus, exert negative inotropism in vertebrate hearts. here, using isolated working eel (anguilla anguilla) and frog (rana esculenta) heart preparations, we have studied the role of the cytoskeleton in the vss-mediated inotropic response. in both eel and frog hearts, vss-mediated-negative inotropy was abolished by treatment with inhibitors of cytoskeleton reorganizat ...200717056132
galanin and its binding sites in the brain of eels subjected to different osmolar conditions.a galanin (gal)-like peptidergic system was investigated in the brain of anguilla anguilla subjected to hyperosmolar and hypoosmolar conditions, by using antisera raised against porcine 1-29 gal. a group of immunoreactive perikaria was identified in the periventricular hypothalamus, in the ventral thalamus, in the pretectal areas and in the optic tectum. immunoreactive perikaria were present in the nucleus lateralis of the torus semicircularis in seawater (sw) adapted eels, and were absent in th ...200616917814
pcb levels in european eel (anguilla anguilla) from two coastal lagoons of the mediterranean.eels are exposed to pollutants due to their unusual life cycle and are vulnerable to contamination associated with sediment due to their diet, feeding habits and territoriality. since the 1980s, a decline in american and european eel populations has been recorded. the causes of this decline still are unknown but pollution from domestic and industrial effluents is known to be involved. since little data is available on pcb contamination in eels from italian waters, pcbs were measured in muscle of ...200616917727
mutation analysis of ras gene in the liver of european eel (anguilla anguilla l.) exposed to benzo[a]pyrene.ras is regarded as one of the most important genes involved in carcinogenesis. such genes have been characterised in several fish species and the presence of ras mutations have already been described in fish populations from hydrocarbon contaminated areas and following experimental exposure to specific contaminants. the aims of this study were to evaluate the dna integrity by comet assay, to isolate the normal ras gene of anguilla anguilla and analyse for the presence of ras gene mutations or ch ...200616828491
polycyclic aromatic hydrocarbon metabolites and 7-ethoxyresorufin o-deethylase activity in caged european eels.this study investigated the contribution of two biomarkers, bile polycyclic aromatic hydrocarbon (pah) metabolites and 7-ethoxyresorufin o-deethylase (erod), activity in the assessment of pah contaminated sites. european eels (anguilla anguilla) were caged in a freshwater stream upstream and downstream from local industrial effluent outlets. bile pah metabolites were recorded as fluorescent aromatic compounds by synchronous fluorescence spectroscopy and as a marker for total pah metabolism: 1-hy ...200616783620
evidence for isolation by time in the european eel (anguilla anguilla l.).life history traits of highly vagile marine species, such as adult reproductive success and larval dispersal, are strongly determined by oceanographic and climatic forces. nevertheless, marine organisms may show restricted dispersal in time and space. patterns of isolation by distance (ibd) have been repeatedly observed in marine species. if spawning time is a function of geographical location, temporal and spatial isolation, can easily be confounded or misinterpreted. in this study, we aimed at ...200616780427
oxidative stress, liver biotransformation and genotoxic effects induced by copper in anguilla anguilla l.--the influence of pre-exposure to beta-naphthoflavone.fish are exposed in the aquatic ecosystems to different classes of pollutants. polycyclic aromatic hydrocarbons (pahs) and heavy metals represent two important classes of aquatic contaminants. thus, one lot of european eels (anguilla anguilla l.) was pre-exposed during 24 h to 2.7 microm beta-naphthoflavone (bnf; a pah-like compound), and subsequently exposed during 24 h to 0, 1 and 2.5 microm copper (cu). additionally, another lot not pre-exposed to bnf was exposed to the same cu concentrations ...200616735051
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
natural hybrids in atlantic eels (anguilla anguilla, a. rostrata): evidence for successful reproduction and fluctuating abundance in space and time.the outcome of natural hybridization is highly variable and depends on the nonexclusive effects of both pre- and post-mating reproductive barriers. the objective of this study was to address three specific questions regarding the dynamics of hybridization between the american and european eels (anguilla rostrata and anguilla anguilla). using 373 aflp loci, 1127 eels were genotyped, representing different life stages from both continents, as well as multiple icelandic locations. we first evaluate ...200616689906
androgen-dependent stimulation of brain dopaminergic systems in the female european eel (anguilla anguilla).dopamine (da), a neurotransmitter present in all vertebrates, is involved in processes such as motor function, learning and behavior, sensory activities, and neuroendocrine control of pituitary hormone release. in the female eel, we analyzed how gonadal steroids regulate brain expression of tyrosine hydroxylase (th), the rate-limiting enzyme in the biosynthesis of da. th mrna levels were assayed by quantitative real-time rt-pcr. th-positive nuclei were also localized by in situ hybridization (is ...200616543374
are dioxin-like contaminants responsible for the eel (anguilla anguilla) drama?eel populations worldwide are dangerously close to collapsing. our study is the first to show that current levels of dioxin-like contaminants are strong candidates because of their devastating effects on development and survival of eel embryos. female and male silver eels were artificially stimulated to maturation and reproduction by treatment with carp pituitary extracts and hcg, respectively. during maturation of female european silver eels, about 60 g fat per kg eel is incorporated in the ooc ...200616508793
oceanic biology: spawning of eels near a seamount.discoveries of the larvae of the european and american eels, anguilla anguilla and a. rostrata, in the sargasso sea and of the japanese eel, a. japonica, in the philippine sea indicate that these freshwater eels migrate thousands of kilometres into the open ocean to spawn. here we pinpoint a spawning location for japanese eels after genetically identifying newly hatched larvae that we collected from the site. the restricted size of this spawning area ensures that the eel larvae enter a particula ...200616495988
effect of the flavonol quercetin on ion transport in the isolated intestine of the eel, anguilla anguilla.flavonoids are phenolic compounds used in fish diet formulations for the control of sex differentiation. consequently it is of interest to know their effects on fish gastrointestinal mucosa that is the first target of these substances after food intake. we studied the effects of the flavonol quercetin on the transepithelial electrical parameters of the isolated intestine of the eel, anguilla anguilla, by employing ussing chamber technique. we showed that luminal quercetin (10(-4) m) reduced the ...200616466967
the eel immune system: present knowledge and the need for research.the european eel, anguilla anguilla, is one of the most important warm water fish species cultured in southern europe and the mediterranean as well as in northern countries including germany, the netherlands and denmark. the japanese eel, a. japonica, is an important cultured fish in several asiatic countries including japan, china and taiwan. during recent decades, research has been performed to elucidate the immune response of these species against different pathogens (viruses, bacteria or par ...200616436117
effects of high-pressure acclimatization on silver eel (anguilla anguilla, l.) slow muscle contraction.as the spawning migration of the eel is supposed to correspond to a long swimming activity at depth, patterns of slow red muscle contraction have been investigated in european silver eel (anguilla anguilla l.) exposed for 3 weeks to 10.1 mpa hydrostatic pressure. the results show that pressure-acclimated eels (male and female) show a three-fold decrease in maximum isometric stress of twitch and tetanic contractions while time to peak force, time from peak force to 90% relaxation and ratio of twi ...200616413804
possible role of calcitonin gene-related peptide in osmoregulation via the endocrine control of the gill in a teleost, the eel, anguilla anguilla.osmoregulation is a major challenge in aquatic animals involving a complex endocrine control. we investigated the potential role of calcitonin gene-related peptide (cgrp, a neuromediator in mammals) in the endocrine control of the gill in a teleost, the eel. transfer from freshwater to seawater induced an hyperosmolality and a concomitant large increase in plasma cgrp levels. specific cgrp binding sites were characterized in the gill and their number was up-regulated after seawater transfer. thi ...200616253389
characterization of a binary tandem domain f-type lectin from striped bass (morone saxatilis).among other functions, lectins play an important role in the innate immune response of vertebrates and invertebrates by recognizing exposed glycans on the surface of potential pathogens. despite the typically weak interaction of lectin domains with their carbohydrate ligands, they usually achieve high avidity through oligomeric structures or by the presence of tandem carbohydrate-binding domains along the polypeptide. the recently described structure of the fucose-binding european eel agglutinin ...200616251191
responses of european eel (anguilla anguilla l.) circulating phagocytes to an in situ closed pulp mill effluent exposure and its association with organ-specific peroxidative damage.the effect of bleached kraft pulp mill effluent (bkpme) persistent compounds on phagocyte activities and its organ-specific influence in gill, kidney and liver was studied in european eel (anguilla anguilla l.). eels were caged and plunged at 3 different sites-50 m (site 1), 100 m (site 2) and 2,000 m (site 3) away from the end of the closed bkpme discharging channel for 8 and 48 h. gill, head kidney and peritoneum phagocytes oxidative burst activity (oba) was measured by the nitroblue tetrazoli ...200616229874
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
morphometry characterisation of european eel spermatozoa with computer-assisted spermatozoa analysis and scanning electron microscopy.the aim of the present study was to characterise european eel spermatozoa morphometrically, as a basis for future studies on the morphological effects of methods for sperm cryopreservation and sperm quality. this characterisation was carried out measuring several spermatozoa morphology parameters (head length, width, area and perimeter) by scanning electron microscopy (sem), in comparison with measurements developed in european eel spermatozoa with computer-assisted morphology analysis (asma). s ...200616185761
analysis of vitellogenin gene induction as a valuable biomarker of estrogenic exposure in various mediterranean fish species.several pollutants have the potential to disrupt the endocrine system in aquatic organisms, and synthesis of vitellogenin (vtg) in male fish is a well-recognized effect of estrogenic xenobiotics. in this respect both the presence of the protein in plasma and the analysis of vtg gene induction may represent valuable biomarkers. the present article describes primers specifically designed for a rt-pcr assay of vtg mrna in various mediterranean fish species. all the species analyzed have great poten ...200616168407
influence of photic environment on the form of the fish electroretinographic off-response.scotopic electroretinogram of dogfish shark (scylliorhinus canicula) and eel (anguilla anguilla) is characterized by a negative off-response, changing in sign under photopic condition. it increased under the effect of increased background illumination, but its amplitude never exceeded that of the b-wave. on the other hand, dark-adapted electroretinograms of two perch-like species, perch (perca fluviatilis) and painted comber (serranus scriba), exhibited a positive off-wave, exceeding the b-wave ...200516154971
photopic vision in eels: evidences of color discrimination.several classes of second-order retinal neurons have been studied electrophysiologically in european eel (anguilla anguilla) from two different localities, lake seliger in russia and the coastal waters of the adriatic sea in montenegro. the majority of l-horizontal cells (68 explored) had both rod and cone inputs, an uncommon phenomenon among teleosts. pronounced color-opponent properties, often taken as pointing to the capacity of color vision, were identified in one amacrine cell, apparently o ...200516154922
why can the eel, unlike the trout, migrate under pressure.in order to elucidate the difference between pressure resistance in trout (onchorhyncus mykiss) and eel (anguilla anguilla), oxygen consumption of red muscle permeabilised cells and mitochondria were measured at 101 ata hydrostatic pressure per se. such an experiment involved the setting up of a special system allowing measurements under high pressure. the results show that hydrostatic pressure strongly alters the oxidative phosphorylation in trout but not in eel, which exhibits mitochondrial pr ...200116120271
panmixia in the european eel: a matter of time...the european eel (anguilla anguilla l.) has been a prime example of the panmixia paradigm because of its extraordinary adaptation to the north atlantic gyral system, semelparous spawning in the sargasso sea and long trans-oceanic migration. recently, this view was challenged by the suggestion of a genetic structure characterized by an isolation-by-distance (ibd) pattern. this is only likely if spawning subpopulations are spatially and/or temporally separated, followed by non-random larval disper ...200516024374
two sites for gtp binding in cathodic haemoglobins from anguilliformes.cathodic haemoglobins of four species of anguilliform fish were characterized from a functional point of view, with special regard to the interaction with their physiological effectors. a series of oxygen-binding experiments at increasing gtp concentrations was carried out in order to compare gtp-binding activities in the absence and presence of saturating amounts of chloride. the results indicated that the cathodic haemoglobin of three species (anguilla anguilla, conger conger and muraena helen ...200516019246
adenosine/nitric oxide crosstalk in the branchial circulation of squalus acanthias and anguilla anguilla.the potent vasomodulator adenosine (ad), thanks to the interaction with by a(1) and a(2) receptors, dilates systemic, coronary and cerebral vasculatures but exert a constrictor action in several vessels of respiratory organs. recent investigations suggest that nitric oxide (no) contributes to ad effects. in fish, both no and ad induce atypical effects compared to mammals. since there is very little information on the role of no and its involvement in mediating the actions of ad in fish, we have ...200515979367
differential regulation of luteinizing hormone and follicle-stimulating hormone expression during ovarian development and under sexual steroid feedback in the european eel.pituitary gonadotropins, luteinizing hormone (lh) and follicle-stimulating hormone (fsh) are, in teleosts as in mammals, under the control of hypothalamic factors and steroid feedbacks. in teleosts, feedback regulations largely vary depending on species and physiological stage. in the present study the regulation of fsh and lh expression was investigated in the european eel, a fish of biological and phylogenetical interest as a representative of an early group of teleosts. the eel fshbeta subuni ...200515961957
the life cycle of paraquimperia tenerrima: a parasite of the european eel anguilla anguilla.previous studies on the life history of the nematode eel specialist paraquimperia tenerrima (nematoda: quimperiidae) have failed to determine whether an intermediate host is required in the life cycle. in the laboratory, eggs failed to hatch below 10 degrees c, hatching occurring only at temperatures between 11 and 30 degrees c. survival of the free-living second stage larvae (l2) was also temperature dependent, with maximal survival between 10 and 20 degrees c. total survival of the free-living ...200515946399
seasonal variability of metallothioneins, cytochrome p450, bile metabolites and oxyradical metabolism in the european eel anguilla anguilla l. (anguillidae) and striped mullet mugil cephalus l. (mugilidae).the european eel anguilla anguilla (anguillidae) and the striped mullet mugil cephalus (mugilidae) are typical inhabitants of mediterranean brackish lagoons, and their utility as bioindicator organisms has already been suggested. the seasonal variability of several potential biomarkers was investigated during a field study carried out in the orbetello lagoon (tuscany, italy). organisms were sampled on a seasonal basis, and analyzed parameters included the levels of hepatic metallothioneins, the ...200515942813
endocrine control of anguilla anguilla glass eel dispersal: effect of thyroid hormones on locomotor activity and rheotactic behavior.dispersal, one of the most important processes in population ecology, is an issue linking physiological and behavioral features. however, the endocrine control of animal dispersal remains poorly understood. here, we tested whether and how thyroid hormones may influence dispersal in glass eels of anguilla anguilla, by testing their influence on locomotor activity and rheotactic behavior. glass eels were caught during their estuarine migration and treated by immersion in either a l-thyroxine (t(4) ...200515919385
brain expression of tyrosine hydroxylase and its regulation by steroid hormones in the european eel quantified by real-time pcr.in the eel, dopamine inhibits pubertal development. to investigate the regulatory mechanisms involved, we developed a quantitative real-time rt-pcr assay for measurement of brain expression of tyrosine hydroxylase (th), the rate-limiting enzyme in the biosynthesis of dopamine. th expression was highest in the olfactory bulb, followed by the di-/mesencephalic areas and the telencephalon/preoptic area. th expression in the optic lobes and hindbrain was low or below the detection limit. in vivo tre ...200515891106
effect of cortisol on aquaporin expression in the esophagus of the european eel, anguilla anguilla.long-term cortisol infusion into freshwater (fw)-adapted eels induced a significant increase in aquaporin-1 (aqp1) mrna expression within the esophageal epithelium of migratory "silver" eels, but not in nonmigratory, immature "yellow" eels. cortisol treatment had no significant effect on the mrna abundance of a second aquaporin-1 isoform, termed aqp1dup, which exhibited a highly variable expression profile among individual members of all fish groups. these results suggest that cortisol, at plasm ...200515891071
dopaminergic inhibition of reproduction in teleost fishes: ecophysiological and evolutionary implications.in many teleosts, dopamine (da) exerts direct inhibitory control on gonadotropes, counteracting the stimulatory effect of gonadotropin-releasing hormone (gnrh) on gonadotropin release. this dual control by gnrh and da has been demonstrated in various adult teleosts and has major implications for aquaculture. because of its unique life cycle, the european eel has provided a powerful model for demonstrating the key role of da in the control of puberty. data from tetrapods suggest that the inhibito ...200515891002
anguilla anguilla l. liver erod induction and genotoxic responses after retene exposure.anguilla anguilla l. (european eel) were exposed for 8, 16, 24, and 72 h to 0 (control), 0.1, 0.3, 0.9, and 2.7 microm retene. a. anguilla l. liver ethoxyresorufin-o-deethylase erod activity significantly increased during the whole exposure period to all retene concentrations, when compared to their controls. the liver cytochrome p450 content only increased after exposure to high retene concentrations (0.9 and 2.7 microm) from 8 to 24 and 72 h, respectively. generally, liver dna integrity decrea ...200515883094
a quantitative real-time rt-pcr assay for european eel tyrosine hydroxylase.dopamine (da) plays a key inhibitory role in pubertal development of the european eel, but how daergic neuronal activity is regulated is not known in this species. in order to investigate the regulation of da inhibition at the molecular level, we developed a quantitative real-time rt-pcr (qrtrt-pcr) assay, using the light cycler system, for the expression of eel tyrosine hydroxylase (th), the rate-limiting enzyme in catecholamine biosynthesis. two different reference genes were compared: the pre ...200515862557
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