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At least 109 records · Page 6Linked to original sources
PubMed2006

Procamallanus (Spirocamallanus) anguillae sp. n. (Camallanidae) and some other nematodes from the Indonesian shortfin eel Anguilla bicolor in Thailand.

A new species of parasitic nematode, Procamallanus (Spirocamallanus) anguillae sp. n. (family Camallanidae), is described based on specimens recovered from the intestine of the Indonesian eel Anguilla bicolor McClelland (type host) from southern Thailand (type locality Phuket Island). It is characterized mainly by the presence of 10-13 spiral ridges in the buccal capsule, length of spicules (366-372 microm and 198-216 microm), presence of a gubernaculum, arrangement of caudal papillae, and by the broad female tail with a digit-like projection bearing two cuticular spikes. In addition, two species of larval nematodes, Physalopteridae gen. sp. and Anisakis cf. simplex (Rudolphi 1809), were recorded from A. bicolor. All species are briefly described and illustrated.

Anguilla↗
PubMed1985

Detection of endocrine cells by immunofluorescence method in the gastroenteropancreatic system of the adult eel, glass-eel, and leptocephalic larva (Anguilla anguilla L.).

Five antisera against insulin (Ins), glucagon (Glu), somatostatin (SRIF), met-enkephalin (met-enk), and serotonin (5-HT) were used for immunofluorescence detection of endocrine cells in pancreas and gastrointestinal tract (GIT) of the European eel (Anguilla anguilla L.) at three stages of development (leptocephalic larva, glass-eel, and adult eel). Comparable distribution of endocrine cells was observed for adults and glass-eels. In their pancreatic islets, positive immunoreactions were obtained only for Ins, SRIF, and Glu; this later was also present in the pancreatic ducts. 5-HT cells were present throughout the GIT. SRIF cells were situated mostly in the stomach and less in the intestine. Met-enk cells were abundant in the pyloric cecum, but less frequent in the intestinal mucosa. Glu cells were present only in the intestine. No insulin-immunoreactive cells could be detected in the GIT. The pancreatic islets of leptocephalic larvae exhibited a strong reaction for SRIF, a weak reaction for Glu, and none at all for Ins, met-Enk, or 5-HT. The GIT of these larvae contained numerous met-enk cells, mainly in the foregut. In the fore- and midgut, cells exhibited a weak fluorescence after treatment with Glu antiserum. No positive immunoreactive cells were observed with 5-HT, SRIF, or Ins antisera.

Anguilla↗
PubMed1986

Effects of hypophysectomy on the testis of the European eel (Anguilla anguilla L.).

The pituitary control of testis activity in the freshwater silver European eel (Anguilla anguilla L.) was investigated by study of some variations of gonad structure and particularly changes in plasma levels of testosterone and 11-oxotestosterone (radioimmunoassay) following hypophysectomy. Germ cells comprised only spermatogonia, which were associated with Sertoli cells to form cysts. No mitotic activity of spermatogonia was observed. Gonadosomatic index (GSI) was low. Plasma levels of the main androgens (testosterone, 11-oxotestosterone) were under 1 ng ml-1. The male gonad appeared immature. After hypophysectomy, GSI decreased rapidly and cysts of germ cells were rapidly dissociated. Plasma level of testosterone decreased significantly, whereas that of 11-oxotestosterone increased significantly. These changes were not observed in sham-operated eels. Thus pituitary control appears essential for the maintenance of structural organization and secretory activity of the immature testis.

Anguilla↗
PubMed1987

Induction of spermatogenesis and spermiation by a single injection of human chorionic gonadotropin in intact and hypophysectomized immature European eel (Anguilla anguilla L.).

Intact and hypophysectomized male silver eels (Anguilla anguilla) in fresh water received a single injection of human chorionic gonadotropin (hCG) (250 C) or solvent (0.15 M NaCl). No effect of solvent was observed. Spermatogonia proliferated in testis of hCG-treated intact or hypophysectomized eels. One month after the injection, primary and secondary spermatocytes were found. After 3 months, numerous spermatozoa were present. In hypophysectomized eels, hCG was also effective even though maturing germ cells were less numerous and spermiation was less frequent than in intact animals. Within 1 week after hCG injection, plasma levels of free and glucuroconjugated androgens (testosterone and 11-oxotestosterone) rose significantly in intact and hypophysectomized fish. The highest values were observed within 1 month, and then plasma levels decreased to pretreatment values. The most important changes were observed in the case of free 11-oxotestosterone. The long-term effects of hCG can be explained partly by the long half-life of this hormone. The effects of hypophysectomy on the response of testis to hCG caused us to think that some endogenous pituitary secretions must interfere in the intact fish so that maximal effects of hCG, especially on the induction of spermiation, are obtained.

Anguilla↗
PubMed1988

Somatostatin-related and glucagon-related peptides with unusual structural features from the European eel (Anguilla anguilla).

Peptides derived from prosomatostatins I and II and from two distinct proglucagons have been isolated from the pancreas of a teleost fish, the European eel (Anguilla anguilla). The product of prosomatostatin I processing, somatostatin-14, is identical to mammalian somatostatin-14. A 25-amino-acid-residue peptide (Ser-Val-Asp-Asn-Gln5-Gln-Gly-Arg-Glu-Arg10-Lys-Ala-Gly-Cys- Lys15-Asn-Phe-Tyr- Trp-Lys20-Gly-Pro-Thr-Ser-Cys25) is derived from prosomatostatin II. Compared with the corresponding peptides from other teleost fish, the eel somatostatin-25 contains the unusual substitution Pro for Phe at position 22. This peptide was also isolated in a form containing a hydroxylsyl residue at position 20. A 29-amino-acid-residue eel glucagon contains four substitutions relative to human glucagon Asn for Ser8, Glu for Asp15, Thr for Ser16, and Ser for Thr29). In common with mammalian and avian glucagons but unlike most other fish glucagons, the eel peptide possesses a glutamine residue at position 3. A peptide derived from a second proglucagon comprises 36 amino acid residues. A 7-residue C-terminal extension to the glucagon sequence shows structural similarity to the corresponding extension in ratfish (Hydrolagus colliei) glucagon and mammalian oxyntomodulin.

Amino Acid Sequence↗
PubMed1995

Production, characterisation and applicability of monoclonal antibodies to European eel (Anguilla anguilla L., 1758) immunoglobulin.

Monoclonal antibodies (mAbs) to European eel (Anguilla anguilla L., 1758) immunoglobulin (Ig) were produced, characterised and tested for applicability in a number of immuno(cyto)chemical assays. The selected mAbs, WEI 1 and WEI 2, were specifically reactive with Ig heavy and light chain, respectively. WEI 1 appeared to react with all or nearly all Ig molecules, B cells and plasma cells. WEI 2 was reactive with a subpopulation of those cells, indicating that European eel possesses at least two antigenically different light chain types. Both mAbs could be used for detection of antigen-specific antibodies in plasma by means of an enzyme-linked immunosorbent assay (ELISA).

Anguilla↗
PubMed1982

Elevated sister chromatid exchange rate in lymphocytes of the European eel (Anguilla anguilla) with cauliflower tumor.

Sister chromatid exchange (SCE) frequency and chromosomal aberration were studied in cultured lymphocytes from the European eel (Anguilla anguilla) with cauliflower tumors. SCE was significantly increased in the affected fishes compared with normal controls, whereas chromosomal aberration did not. In comparison to normal cells, the lymphocytes responding to phytohemagglutinin M (PHA-M) in cultures from tumorous eels showed no evidence of cell cycle retardation. A possible mechanism for elevation of SCE and the significance of this finding relation to the etiology were discussed.

Anguilla↗
PubMedDate not supplied

Chromatographic and immunological evidence for mammalian GnRH and chicken GnRH II in eel (Anguilla anguilla) brain and pituitary.

Gonadotropin-releasing hormone (GnRH) peptides in the brain and pituitary of the European eel (Anguilla anguilla) were investigated by reverse phase high performance liquid chromatography (HPLC) and radioimmunoassay with region-specific antisera. Two GnRH molecular forms were demonstrated in brain and pituitary extracts. One form eluted in the same position as synthetic mammalian GnRH on HPLC and was recognized by antibodies directed against the NH2 and COOH termini of mammalian GnRH as well as by antibodies to the middle region. The second form eluted in the same position as synthetic chicken GnRH II and was recognized by specific antibodies to this molecule. Salmon GnRH and chicken GnRH I were not detected. The occurrence of mammalian GnRH in teleost fish suggests that this molecular form is more ancient than was previously suspected and arose earlier than in primitive tetrapods, or that it has arisen in the eel through random mutation of salmon GnRH. The lack of salmon GnRH in the eel brain indicates that this molecular form is not common to all teleost species. The finding in eel brain of chicken GnRH II, which has previously been described in species of Mammalia, Aves, Reptilia, Amphibia, Osteichthyes, and Chondrichthyes, supports our hypothesis that this widespread structural variant may represent an early evolved and conserved form of GnRH.

Anguilla↗
PubMed1983

Separation by velocity sedimentation of the gill epithelial cells and their ATPases activities in the seawater adapted eel Anguilla anguilla L.

The separation of cell populations by sedimentation was carried out on heterogeneous suspensions of branchial cells of the seawater adapted eel Anguilla anguilla. The cell sedimentation rates vary mainly in relation to size and permit the separation of enriched fractions of chloride cells and respiratory cells. The method is described and discussed. The homogeneity of the separated populations was checked by microscopy and particle counting. An enrichment of 95% by volume concentration of the two main cell types was obtained. The separated cells had good viability (85-95% viable). This was controlled by Trypan blue exclusion tests. The adenosine triphosphatase activities of the different cell populations were measured and compared.

Adenosine Triphosphatases↗
PubMed1985

Temperature acclimation and oxygen binding properties of blood of the European eel, Anguilla anguilla.

Temperature acclimation of the European eel, Anguilla anguilla, resulted in red cell GTP/Hb molar ratios of 1.20, 1.77 and 0.80 at 2, 17 and 29 degrees C, respectively. A small increase in blood oxygen capacity was present in 29 degrees C acclimated eels. The CO2 Bohr effect and the shape of the oxygen binding curve (n-Hill) were invariant with both temperature and GTP/Hb. The significant differences in the GTP/Hb ratio corresponded with a strong enhancement of the temperature effect on blood oxygen affinity between 2 and 17 degrees C and a similarly strong compensation between 17 and 29 degrees C. Predicted in vivo P50 values were 3.0, 13.8 and 17.6 mmHg at 2 degrees C, 17 and 29 degrees C, respectively. The adaptational value of these findings are discussed in relation to standard metabolic rates at the various temperatures. A tentative hypothesis is proposed that the present study confirms and expands earlier work and supports the contention that adjustments in blood oxygen affinity of thermally acclimated teleosts serve to provide them with an unloading O2 tension for diffusion closely matching the standard oxygen requirements at the various temperatures.

Acclimatization↗
PubMed1986

Suppression of plasma thyroid hormone concentrations by cortisol in the European eel Anguilla anguilla.

Female European eels, Anguilla anguilla, were given a single intra-arterial injection via a catheter of cortisol hemisuccinate at doses ranging from 3.5 to 35 micrograms (15 to 150 micrograms/kg body wt), yielding mean plasma cortisol levels of 87-410 ng/ml 2 hr after injection. Cortisol treatment (17.5 and 35 micrograms) significantly decreased plasma levels of thyroxine (T4) and triiodothyronine (T3) within 24 hr relative to those in control fish. Cortisol treatment (35 micrograms) appeared to increase the clearance rate of 125I-T3 from plasma and the proportionate uptake of radioactivity in certain tissues after injection of 125I-T3. Cortisol treatment had no apparent effect on the plasma clearance of 125I-T4 or tissue distribution of radioactivity after injection of 125I-T4.

Anguilla↗
PubMed1986

The relationship of eel Anguilla anguilla (L.) body size, lipid, protein, glucose, ash, moisture composition and enzyme activity (aldolase).

Body composition: protein, lipid, ash, moisture; and enzyme activity (aldolase) were studied in European eels (Anguilla anguilla) of various sizes. The fish were brought to the laboratory as glass eels (0.35 g) and maintained under controlled conditions (23 degrees C) for one year. After one year of growth, various sizes (between 9 and 420 g) were found. Significant correlation coefficients of the equation W = a ln C + b (where W = body weight, in g; C = composition, % or activity, u; and a,b are constants) were found among the composition parameters: protein, lipid, glucose and aldolase. Relative amounts of protein, glucose, moisture, ash and aldolase activity were found to decrease with an increase in the weight of eels, but the percentage of fat was higher in large eels than in small ones.

Anguilla↗
PubMed1987

The effect of pressure on the lateral swimming muscle of the European eel Anguilla anguilla and the deep sea eel Histiobranchus bathybius; results of Challenger cruise 6B/85.

1. The viability of Histiobranchus lateral muscle was prolonged up to 7 times by recompression of the tissue. 2. The maximum twitch contraction force of both Anguilla and Histiobranchus was recorded at a pressure between 150 and 350 atm. At 1 atm Anguilla developed 60% maximum force and Histiobranchus 10-20% maximum force. 3. Twitch contraction time doubled for a pressure increase of 400 atm. This effect is predicted to halve the maximum swimming speed at 4000 m and is discussed in relation to muscle force and anaerobic support.

Anguilla↗
PubMed1987

Effect of dietary carbohydrate source on soluble protein glucose concentration and enzyme activity (aldolase) of European eels (Anguilla anguilla L.).

This study was undertaken to determine the influence of dietary carbohydrate sources: wheat meal, bread meal, soluble corn starch, native potato starch and sorghum meal, on soluble protein, enzyme activity (aldolase) and glucose concentration in muscle and liver of European eels (Anguilla anguilla). There was less soluble protein in both muscle and liver of eels fed 30% wheat meal or bread meal than the other experimental groups. However, eels fed 30% bread meal or soluble corn starch had a higher glucose concentration in muscle and liver than the other experimental groups. High enzyme activity (aldolase) was found in the liver of eels fed 30% wheat meal, bread meal or soluble starch.

Anguilla↗
PubMedDate not supplied

Ion transport across the isolated intestinal mucosa of Anguilla anguilla (Pisces).

The posterior intestine of freshwater-adapted Anguilla anguilla has a serosa negative transepithelial potential difference (TPD), and a current corresponding to the flow of negative current towards serosa. The TPD and the short-circuit current (SCC) were inhibited by Na+ and K+ withdrawal, and Cl- substitution or BA2+ addition inverts TPD and SCC, suggesting a Cl- and Na+ current mucosa-serosa, a K(+)-Cl- cotransport and a K+ channel in the mucosal side. The TPD and SCC were inhibited by ouabain, DIDS, furosemide and amiloride, indicating the presence of a Na(+)-K(+)-ATPase, and Cl-/HCO3-,Na(+)-K(+)-Cl- and Na+/H+ cotransporters.

Anguilla↗
PubMed1994

A new mannan-binding lectin from the serum of the eel (Anguilla anguilla L.): isolation, characterization and comparison with the fucose-specific serum lectin.

A new mannan-binding lectin (MBL) and a previously described fucose-binding lectin (FBL) have been isolated from serum of Anguilla anguilla by affinity chromatography on A-peptone-Sepharose in combination with electroelution (MBL) or affinity chromatography using alpha-L-fucose-agarose (FBL). MBL has a mol. wt of approximately 246,000 and is composed of identical subunits of approximately 24,000, two of each are always covalently linked. FBL has a mol. wt of about 121,000 and consists of four subunits of 30,000, which, upon reduction are split into two identical subunits of 15,000. Upon isoelectric focusing MBL displays four bands ranging from pH 4.8 to 5.2. FBL shows 17-20 bands between pH 5.5 and 6.2. Of the inhibitors utilized, hemagglutination activity of MBL is inhibited only by mannan, whereas FBL activity is inhibited by several glycosubstances. MBL and FBL activity is constant between pH 4 and 10 and 5 and 10, respectively. Temperatures above 55 degrees C totally destroy MBL activity whereas FBL activity remains constant up to 75 degrees C.

Anguilla↗
PubMed1995

Primary sequence, tissue specificity and expression of the Na+,K(+)-ATPase alpha 1 subunit in the European eel (Anguilla anguilla).

The entire cDNA nucleotide sequence of the Na+,K(+)-ATPase alpha 1 isoform was cloned from the gills of the European eel (Anguilla anguilla) by a PCR based method. The amino acid sequence translated from the sequence shared 89.4 and 85.6% homology respectively with previously published Na+,K(+)-ATPase alpha subunit sequences from elasmobranch (Torpedo californica) and teleost (Catostomus commersoni) fish. The size of Na+,K(+)-ATPase alpha 1 mRNA transcripts in eel tissues was demonstrated to be 3.5 kb, except in the ovary where a 3.7 kb transcript existed. Na+,K(+)-ATPase alpha 1 mRNA was present at some level in all tissues investigated with the exception of cardiac and skeletal muscle where no Na+,K(+)-ATPase alpha 1 mRNA was detectable. The level of branchial Na+,K(+)-ATPase alpha 1 mRNA increased after the adaptation of freshwater eels to normal or double concentration seawater.

Adaptation, Physiological↗
PubMed1983

Seasonal variations in circadian rhythm of hypothalamic catecholamine content in the eel (Anguilla anguilla L.).

1. Changes in catecholamine content (CA) in hypothalamus of male and female eel (Anguilla anguilla L.) were defined using the Falck-Hillarp histochemical fluorescence method for a 24-hr period during the summer (L:D = 16:8) and winter (L:D = 8:16). 2. A circadian rhythm in the catecholamine content was found in the hypothalamus. CA content was lower by night than by day. 3. A longer light day (summer period) caused the shifting of rhythm phase in CA content. 4. Sex of eels does not affect CA content in the hypothalamus.

Anguilla↗