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At least 145 records · Page 8Linked to original sources
PubMed2000

Identification of maturation-inducing steroid in a freshwater perch Anabas testudineus and differential responses of intact follicles and denuded oocytes to cyclic AMP in oocyte maturation.

Postvitellogenic follicles of freshwater perch Anabas testudineus incubated with [(3)H]pregnenolone as exogenous precursor produced several metabolites, including 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (DHP) and 5 beta-pregnane-3 alpha, 17 alpha,20 beta-triol (5 beta-3 alpha,17 alpha,20 beta-P). These were identified by chromatography, microchemical reactions, and crystallization to constant specific activity. Following stimulation with fish (perch) pituitary extract (FPE) there was significant high production of DHP and 5 beta-3 alpha,17 alpha,20 beta-P, concomitant with a high percentage of germinal vesicle breakdown (GVBD). Inhibitor of steroidogenesis (trilostane) and inhibitors of protein synthesis (cycloheximide and actinomycin-D) completely blocked FPE-induced pregnenolone metabolism and oocyte maturation. The effectiveness of various C(21) steroids in inducing GVBD was examined. Results indicate that DHP was the most potent inducer of GVBD than other structurally related C(21) steroids. In intact follicles, FPE-stimulated production of DHP was shown to be mediated through the adenylate cyclase-cAMP pathway. Addition of IBMX or forskolin, which increases the endogenous cAMP level, as well as directly supplementing dbcAMP to the incubation medium, had no inhibitory effect on DHP-induced GVBD in the intact follicles. But all these agents were shown to inhibit GVBD in fully denuded oocytes. This study provides evidence that DHP, produced by postvitellogenic follicles through the adenylate cyclase-cAMP pathway, is the maturation-inducing steroid in freshwater perch and that the role played by cAMP in the induction of GVBD in intact follicles is different from that in the denuded oocytes. J. Exp. Zool. 287:294-303, 2000.

1-Methyl-3-isobutylxanthine↗
PubMedDate not supplied

[Interrelation between the food spectrum of perch fry (Perca fluvatilis L.) and macrozoobenthos structure in experimental mesocosms].

In experimental ecosystems that accommodate perch fry (Perca fluviatilis), significant structural changes within the benthic communities occurred under the effect of fish feeding on oligochaetes and on the larvae of chidonomids and other insects. Perch fry began to consume benthic animals at early developmental stages (C1-C2). The transition to regular feeding under experimental condition occurred at the D2-E stage (days 30-40), when the benthic community reached a developmental peak. The quantitative parameters characterizing the compositions of perch stomach contents and the main groups of zoobenthos closely correlated with each other. The dynamics of quantitative parameters of these animal groups (except for mollusks) proved to be determined both by the specific features of their life cycles and by the degree of consumption.

Animals↗
PubMedDate not supplied

[Seasonal variations of the localization of the Bunodera luciopercae marites (Trematoda: Bunoderidae) in three species of perch fishes].

Distribution of Bunodera luciopercae marites in the intestine of the fuff, sande and perch were studied in the Rybinsk Reservoir. For the fuff and perch fry, except three summer months, the more proportion of helminths was observed in the posterior region of the intestine. Because of a continuous passage of B. luciopercae in predatory fishes (sanders and adult perches), more proportion of trematodes was always observed in anterior region of the intestine. In all groups of hosts, 20-30% of total parasite number was registered in the middle intestine.

Animals↗
PubMedDate not supplied

[Studies of oligosaccharide specificity of perch roe fucolectin, using gold labeled neoglycoproteins].

The specificity of perch (Perca fluviatilis) roe fucolectin was studied using the protein dot blot technique, followed by detection with colloidal gold-labeled neoglycoproteins bearing human milk polysaccharides. The strongest binding was noted with the H type 1 pentasaccharide lacto-N-fucopentaose (LNFP I, Fuc alpha 1-2 Gal beta 1-3 GlcNAc beta 1-3 Gal beta 1-4Glc); the interaction with the H type 6 trisaccharide 2'-fucosyllactose (2-FL, Fuc alpha 1-2 Gal beta 1-4 Glc) was weaker. Binding of the perch lectin to the Lewis antigens (associated with tumors and embryonic tissues) was also studied. It was found that the lectin weakly interacted with the hexasaccharide lacto-N-difucohexaose I, Fuc alpha 1-2 Gal beta 1-3[Fuc alpha 1-4]GlcNac beta 1-3 Gal beta 1-4 Glc), but not with Lea, Lec, Lex antigens. Thus, perch roe lectin exhibited pronounced differences in carbohydrate specificity from other fucolectins--a feature that may be used in structural studies and isolation of fucose-containing glycoconjugates.

Animals↗
PubMed2002

In vitro production of ovarian steroids in yellow perch (Perca flavescens): effects of photothermal manipulation, gonadotropin and phorbol ester.

We investigated the capacity of ovaries of yellow perch to produce steroid hormones in vitro and the ovarian response to gonadotropin and phorbol ester during the annual reproductive cycle. The effects of photothermal manipulation on perch gonadal steroidogenesis and its regulation have also been examined. Initially, all females kept indoors were exposed to the same water temperature and photoperiod. By the end of August, following the first sampling, fish were submitted to different photothermal regimes. Group A was maintained under photothermal conditions characteristic for southern Ohio. Group B was submitted to a condensed light/temperature regime designed to accelerate physiological changes that depend on photothermal stimuli. In group A, basal in vitro production of ovarian estradiol (E2) was the highest in October and November, and hCG significantly stimulated E2 secretion during the entire period of vitellogenesis (October-January). In this group, the highest production of basal testosterone (T) was observed before spawning. hCG-stimulated production of T was highest at the beginning of vitellogenesis. Gonadotropin stimulated T production before spawning, a time when gonadotropin was unable to stimulate E2 production. Phorbol ester (PDBu) stimulated E2 and T production during vitellogenesis at the same time points as hCG did (E2: December, January; T: December). hCG-stimulated T production was not mimicked by PDBu in April. Condensing of the photothermal cycle resulted in diminished ovarian production of E2 during vitellogenesis. Moreover, the fish submitted to a condensed photothermal cycle demonstrated augmented T production during the postvitellogenic stage of ovarian development. Ovaries of group B did not respond to PDBu. Generally, the seasonal fluctuations in ovarian capacity to produce E2 and T as well as in gonadal responsiveness to gonadotropin observed in female yellow perch illustrate the dynamic nature of ovarian endocrine function. The lack of response to gonadotropin with regard to E2 production prior to spawning is not due to insensitivity to gonadotropin, but rather due to some deficiency in steroidogenesis (e.g. reduced aromatase activity). It appears also that ovarian steroidogenesis and its regulation are dependent on annual changes of photothermal conditions.

Animals↗
PubMedDate not supplied

Isoelectric focusing identification of four freshwater fish commercially labeled "perch".

Isoelectric focusing (IEF) was used to distinguish 4 freshwater fish species that are sold in the European Union under the generic label of "perch": Perca fluviatilis (European perch), Lates niloticus (Nile perch), Stizostedion lucioperca (European pikeperch), and Morone chrysops x saxatilis (Sunshine bass). These species have different commercial values but are easily interchangeable because they are sold already filleted, in view of the numerous bones of the whole fish. IEF of the water-soluble proteins extracted from fish muscle resulted in species-specific patterns. None of the bands was common to all 4 species. Intraspecies polymorphism was low and did not concern the bands identified as characteristic of the species.

Animals↗
PubMed1980

Distribution and elimination of a polychlorinated biphenyl after acute dietary exposure in yellow perch and rainbow trout.

Distribution and elimination of a single polychlorinated biphenyl isomer (2,5,2',5'-tetrachloro[14C]biphenyl, 4-CB) were compared in a nonfatty fish (yellow perch) and a fatty fish (rainbow trout). Adult fish were exposed acutely to 4-CB (0.8 microgram/fish) by the oral or intraperitoneal route and were killed at designated times thereafter for one month. Whole body elimination of 4-CB was similar in both species with 20 to 30% of the radioactive 4-CB being eliminated in the first 3 to 4 days after treatment, but very little thereafter. Also, the same extent of elimination was seen when the compound was given orally or intraperitoneally. Tissue distribution of 4-CB residues was different in the two species. Perch relied on viscera and carcass as main 4-CB distribution sites and skeletal muscle, skin and scales as minor sites. In rainbow trout, on the other hand, skeletal muscle and carcass were major distribution sites, whereas viscera and skin were minor sites. This species difference in 4-CB distribution was not due to a difference in sexual maturity of the perch and trout, because a build-up of eggs or sperm was not present in the peritoneal cavity of either species.

Animals↗
PubMed1984

Plasma thyroxine levels in freshwater perch: influence of season, gonadotropins, and gonadal hormones.

Plasma thyroxine (T4) of a freshwater female perch Anabas testudineus (Bloch) has been measured by specific radioimmunoassay (RIA). Monitoring of plasma T4 throughout the year showed that July to early September (spawning stage) had the highest T4 and late September to January (postspawning stage) had the lowest T4. The plasma T4 cycle was coincident with the ovarian cycle. Treatment of intact perch with salmon gonadotropin (SG-G100) or ovine LH (500 ng/100 g body wt) markedly enhanced plasma T4 levels. Ovine FSH was without any effect. Ovarian steroids, estrone and 17 beta-estradiol (100 ng/100 g body wt), also significantly augmented T4 level whereas estriol or progesterone had no such effect. There was a striking fall of plasma T4 in ovariectomized fish. The drop of T4 due to ovariectomy could not be reversed by SG-G100 but administration of estrone or 17 beta-estradiol to ovariectomized fish effectively reversed the drop of plasma T4 level. These findings suggest that gonadotropin's stimulatory effect on perch thyroid is mediated via the release of ovarian steroids.

Animals↗
PubMed1989

Caesium-137 in Perch in Swedish Lakes after Chernobyl-present situation, relationships and trends.

The Chernobyl accident, and the general acidification of Swedish water systems, form the base for this project. The aims of the work have been to present results on the linkage between the concentration of Cs-137 in fish, lake load of Cs and lake characteristics, to give a preliminary prognosis on the recovery, and to put the results within a wider framework of environmental hazard analysis. A broad set of data on limnology, morphometry and drainage area conditions from 41 lakes were collected during 1986 and 1987. Cs-137 was determined in 1 + perch (Cs-pe, 1-year-old perch), water, material collected by sediment traps and from surficial sediments. The main results are as follows. The average value of Cs-pe for all lakes has dropped from 9800 Bq kg(-1) (wet) to 5040 between the 2 years. Generally, the decrease is between 5 and 90%. We have tested if any factor(s) could be specifically linked to this decrease-no such factors have been found. The concentrations of Cs in sediment traps have, on average, decreased by 80%. Very high correlations exist between Cs-pe and the caesium load as determined from the sediment traps. Between 1 and 10% (mean 3.9%) of the initial fall-out deposition to the drainage area was transported from land to water during June to August 1986. The variation in initial fall-out deposition explains 65-69% of the variability in Cs-pe; the degree of explanation (= coefficient of determination, r2) increases to about 85% if one also takes into account the lake water hardness and totP. A map showing with lakes likely to have 1 + perch with higher mean Cs-concentrations than 1500 Bq kg(-1) wet is presented. Between 4000 and 7000 lakes in Sweden appear to have Cs-pe higher than 1500 Bq kg(-1) wet, figures which emphasize the serious impact of the Chernobyl accident on the environmental conditions in Sweden.

Journal Article↗
PubMed1985

The enhancing effect of spawning on elimination of a persistent polychlorinated biphenyl from female yellow perch.

Distribution and elimination of 2,5,2',5'-tetrachloro[14C]biphenyl (4-CB) were studied for 6 months after exposing sexually mature female yellow perch to the compound in water and transferring them to flowing 4-CB-free water. Perch that were exposed in January spawned in May, and the study was terminated in June. During the first 41/2 months after exposure, the t1/2 for whole-body elimination was 22 weeks, primarily by elimination of 4-CB from the viscera and carcass. During spawning, enhanced elimination (t1/2 less than 0.7 weeks) was due to the voiding of eggs containing 4-CB. After spawning, whole-body elimination returned to a slower rate (t1/2 = 16.3 weeks). Prior to the enhancement in 4-CB elimination rate during spawning, there was a redistribution of 4-CB residues within the body of the perch which was characterized by a transfer of 4-CB residues from primarily the carcass and viscera to eggs. Two weeks after exposure, 30% of the initial 4-CB body burden was distributed to the eggs, whereas just prior to spawning, about 50% was present in this tissue. These findings demonstrate that egg maturation and spawning result in a significant reduction in the body burden of a persistent polychlorinated biphenyl in a lean-fish species.

Animals↗
PubMed1975

A comparison of food habits of white perch (Morone americana) in the heated effluent canal of a steam electric station and in an adjacent river system.

Analysis of the stomach contents of 97 white perch, Morone americana, taken from the effluent canal of a steam electric station (S.E.S.) and 106 white perch from adjacent Patuxent River waters indicated similar food habits from September 1970 through August 1971. However, 35% of all white perch taken from the heated effluent canal contained small pieces of coal and cinders, whereas only 3% of the river specimens contained such items in their stomachs. Fly ash and coal dust are present on the bottom of the S.E.S. canal, whereas little such material, if any, can be found on the river bottom in the study area. This suggests the canal fish were actively feeding in the heated effluent and not simply moving into the canal after feeding in the river. No significant difference (Pgreater than0.05) was found between the average wet weight stomach contents of the river and canal fish within the same mouth.

Animals↗
PubMed2005

Are high perches in the blackcap Sylvia atricapilla song or listening posts? A sound transmission study.

Birds often sing from high perches referred to as song posts. However, birds also listen and keep a lookout from these perches. We used a sound transmission experiment to investigate the changes for receiving and sending conditions that a territorial songbird may experience by moving upwards in the vegetation. Representative song elements of the blackcap Sylvia atricapilla were transmitted in a forest habitat in spring using a complete factorial design with natural transmission distances and speaker and microphone heights. Four aspects of sound degradation were quantified: signal-to-noise ratio, excess attenuation, distortion within the sounds determined as a blur ratio, and prolongation of the sounds with "tails" of echoes determined as a tail-to-signal ratio. All four measures indicated that degradation decreased with speaker and microphone height. However, the decrease was considerably higher for the microphone than for the speaker. This suggests that choosing high perches in a forest at spring results in more benefits to blackcaps in terms of improved communication conditions when they act as receivers than as senders.

Amplifiers, Electronic↗
PubMed2004

Locomotion of lizards on inclines and perches: hindlimb kinematics of an arboreal specialist and a terrestrial generalist.

Arboreal animals, especially lizards, often traverse three-dimensional networks of narrow perches with variable and steep inclines, but the effects of both incline and narrow surfaces on the locomotor movement and function of limbs are poorly understood. Thus, we quantified the three-dimensional hindlimb kinematics of a specialized arboreal lizard, Chamaeleo calyptratus, moving horizontally, and up and down a 30 degrees incline on a narrow (2.4 cm) perch and a flat surface. We compared the flat-surface data of C. calyptratus with those of an anatomically generalized terrestrial lizard, Dipsosaurus dorsalis. Inclines had significant main effects for relatively few kinematic variables of C. calyptratus (11%) compared to D. dorsalis (73%). For C. calyptratus, the main effects of locomotor surface were nearly three times more widespread than those of incline. The foot of C. calyptratus was markedly anterior to the hip at footfall, primarily as a result of an unusually extended knee for a lizard. A large amount of knee flexion during early stance may be used by C. calyptratus to actively pull the body forward in a manner not found in D. dorsalis. Unexpectedly, the pelvic rotation of C. calyptratus greatly exceeded that of D. dorsalis and, unlike D. dorsalis, was not affected by incline. The more medial location of the foot of C. calyptratus on the narrow perch during stance was primarily a result of knee flexion rather than femur depression. Unlike previous qualitative descriptions of chameleons, our data for the hindlimb posture of C. calyptratus during stance indicate that the limb was not particularly erect.

Adaptation, Biological↗
PubMed2003

Exploitation of Erythrina dominguezii Hassl. (Fabaceae) nectar by perching birds in a dry forest in western Brazil.

Among the vertebrate pollinated plants, the genus Erythrina includes tree species in which birds are the pollen vectors. Two groups in this genus may be distinguished: a) the hummingbird, and b) the perching bird pollinated species. Erythrina dominguezii is included in the second group and occurs in deciduous/semi-deciduous forests in the southwestern neotropics. I studied the exploitation of Erythrina dominguezii nectar by perching birds in a dry forest in western Brazil. Six perching bird species from two distinct groups (Psittacidae: Brotogeris chiriri, Nandayus nenday, Aratinga acuticaudata; Icterinae: Psarocolius decumanus, Icterus cayanensis, I. icterus) consumed its nectar. The two most important consumers were Brotogeris chiriri (51.5% of the flowers visited by birds) and Psarocolius decumanus (20%). While B. chiriri was a flower predator, P. decumanus removed the nectar without damaging the flowers which it opened by inserting its large bill between the standard and the keel. Nandayus nenday, Aratinga acuticaudata, and I. icterus exploited the nectar like P. decumanus, and presumably also contributed to pollen transfer. As the flowering in E. dominguezii was intense and synchronous during the dryest period of the year, and its nectar was highly consumed by birds, the present data suggest that the nectar of this species may be important as an alternative resource to frugivorous/omnivorous birds when other resources are scarce.

Animals↗
PubMedDate not supplied

[L-fucose-specific lectin from pike perch (Lucioperca lucioperca L.) roe. Purification and studies of carbohydrate specificity].

L-fucose-specific lectin was purified from pike perch (Lucioperca lucioperca L.) roe by affinity chromatography on ovariomucine H-sepharose from a human ovary cyst. Three bands were detected after disk-electrophoresis in PAAG in alkaline (pH 8.9) and five bands--in acidic system (pH 4.3). According to electrophoresis data in 15% SDS-PAGE the lectin contains two components with molecular weight 13-14 kDa. Molecular weight of the lectin is 50 kDa according to gel-chromatography on tojopearl HW-55. The immunochemical properties of the lectins from perch (Persa fluviatilis L.) roe and pike perch (Lucioperca lucioperca L.) roe are similar.

Animals↗
PubMed1981

[1st findings of Anisakis larvae in pike perches, Stizostedion lucioperca, in coastal waters of the Baltic Sea].

For the first time Anisakis larvae were found in pike perches, Stizostedion lucioperca (L), caught in GDR coastal waters. Herrings parasitized by Anisakis are regarded as the source of infestation, for herrings represent an important part of the food of the pike perch. The occurrence of anisakiasis by eating pike perch is very unlikely considering eating habits in the GDR. The occurrence of larvae as "natural indicators" can be applied in fish biological research.

Animals↗
PubMed1994

Hereditary disorders in the French Canadian population of Quebec. II. Contribution of Perche.

In our previous paper (De Braekeleer and Dao 1994) we showed that most of the hereditary disorders present in the French Canadian population of Canada cluster in eastern Quebec. Furthermore, the disorders probably were brought to Nouvelle-France in the seventeenth century by migrants coming from Perche, France. Here, the analysis of several historical, social, and demographic factors shows that, rather than migrants coming from other French provinces, migrants from Perche came from a limited area and settled in eastern Quebec, preferentially on the north shore of the St. Lawrence River. They arrived earlier than the other migrants and had a larger descendance. However, only a limited number of migrants from Perche were found in the founding nucleus of the hereditary disorders. Further analysis shows that the social system had major consequences on migration, marriage, kin network, and family behavior. Therefore the presence and the high frequency of most of the hereditary disorders in the French Canadian population appear to be the result of founder effect and genetic drift.

Cluster Analysis↗
PubMed2002

High performance liquid chromatographic separation of steroids from ovarian follicles of fresh water perch Anabas testudineus: identification and characterization of the maturation-inducing hormone.

Accurate separation and identification of steroids from the postvitellogenic ovarian follicles of Indian climbing perch Anabas testudineus was performed by high-performance liquid chromatography (HPLC) and specific radioimmunoassay (RIA). The steroids from such follicles, incubated in Cortland's saline with or without homologous fish pituitary extract (FPE), were extracted with dichloromethane and separated on a micro Bondapak C(18) column. Identification of the HPLC fractions was further confirmed by thin layer chromatography. As HPLC peaks for 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (DHP) and testosterone (T) were close, clear separation of these steroids and accurate measurement of their quantities was achieved by RIA of HPLC fractions using specific antibodies. Altogether, nine eluted fractions in the FPE-untreated and ten in FPE-treated samples were obtained. Of these, six were identified as: 5 beta-pregnan-3 alpha,17 alpha,20 beta-triol (5 beta-3 alpha,17 alpha,20 beta-P); DHP; T; 17 alpha-hydroxyprogesterone (17 alpha-P(4)); progesterone (P(4)); and androstenedione (AD). Three fractions from untreated and four from FPE-treated samples, however, remained unidentified. Of all the HPLC fractions examined for their relative maturational inducing (MI) potency on full grown (postvitellogenic) ovarian follicles of perch, the fraction identified as DHP was found to be the most effective inducer of germinal vesicle breakdown (GVBD) both at low and high concentrations. Fractions identified as 5 beta-3 alpha, 17 alpha, 20 beta-P and 17alpha-P(4) could induce only 32% and 20% GVBD at their highest concentration, while none of the unidentified fractions showed any MI activity. FPE caused increased production of DHP, testosterone, and 5 beta-3 alpha, 17 alpha, 20 beta-P. The qualitative differences between the fractions obtained from FPE-treated samples and those from FPE-untreated samples were only the appearance of a new polar metabolite of unknown function. The present study showed that, as a single steroid, DHP was the most potent MIH for A. testudineus.

Animals↗