摘要:

AbstractChitin and protein are major components of crustacean exoskeletons. In insect cuticles, glycosylation is one of the predominant post‐translational modifications of the proteins. Investigations of glycosylation of crustacean exoskeletal proteins are much more limited. We have used lectins to follow changes in glycosylation of proteins in the exoskeletal layers of the Bermuda land crabGecarcinus lateralisat selected stages of the intermolt cycle. Proteins extracted from the individual layers during anecdysis and late proecdysis as well as from the layers of exuviae were electrophoresed on sodium dodecyl sulfate (SDS)‐polyacrylamidegels, blotted to polyvinylidene difluoride membranes, and reacted with biotinylated lectins. Seven lectins were tested: concanavalin A (Con A), soybean agglutinin (SBA), wheat germ agglutinin (WGA),Dolichos biflorusagglutinin (DBA),Ulex europaeusagglutinin(UEA I),Ricinus communisagglutinin (RCA120), and peanut agglutinin (PNA). Con A, which binds primarily to mannose residues, produced the strongest signals. Duringanecdysis, most of the binding occurred with protein bands larger than 31 kDa, while in lateproecdysis and in layers from exuviae, small as well as large proteins were bound.N‐glycosidase F digestion of electrotransferred proteins and subsequent treatment with Con A indicated both N‐linked and O‐linked glycosylation. SBA, which binds to both α‐and β‐linkedN‐acetylgalactosamine, was the second most reactive lectin, and the number of exoskeletal proteins to which it bound also increased in late proecdysis. Little or no binding of DBA, RCA120, or PNA, which react with α‐linkedN‐acetylgalactosamine, indicated that theN‐acetylgalactosamine was β‐linked. The specificity of binding of Con A or SBA was demonstrated by inhibition with methyl‐α‐D‐mannopyranoside andN‐acetyl‐D‐galactosamine, respectively. Binding of UEAI revealed the presence of fucose residues on a few proteins. As the exoskeleton was degraded during proecdysis, protein bands that were not detected by lectin binding during anecdysis were modified in such a way that they became acces

ISSN:0022-104X    

DOI:10.1002/jez.1402710602

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractRainbow trout (Oncorhynchus mykiss) fasted for 4 months had lower plasma glucose concentration and hepatocyte glycogen content than the fed fish. Gluconeogenesis from alanine in the fasted fish was not significantly different from that of the fed fish, Whereas both alanine glyconeogenesis and oxidation increased with fasting by 400% and 300%, respectively. Glyconeogenesis from glucose was not significantly different with fasting, whereas glucose oxidation decreased significantly with fasting. The presence of glucose (10 mM) in the medium did not modify alanine glyconeogenesis or gluconeogenesis in either the fed or the fasted groups. However, glucose did increase alanine oxidation in the fed group but not in the fasted group, this response being further stimulated in the presence of insulin. Alanine (2 mM) in the medium had no effect on glyconeogenesis from glucose in either fed or fasted trout hepatocytes. Insulin significantly decreased glucose oxidation in the fed fish, whereas the insulin effect on glucose oxidation in the fasted fish occurred only in the presence of alanine. The results indicate that nutritional state affects hepatocyte responsiveness to substrate utilization and insulin stimulation in trout. Specifically, the hepatocyte potential for glyconeogenesis is enhanced in the fasted fish, although this increased glycogen production is not due to an increased glucose utilization. © 1995 Wiley‐Liss, I

ISSN:0022-104X    

DOI:10.1002/jez.1402710603

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractChemical irritation appears to be modulated by similar mechanisms in birds and mammals, despite an apparent difference between the two taxa for what constitutes a chemical irritant. Prostaglandin E1, a well‐described mammalian pain modulating substance, was not itself aversive to starlings, although it did sensitize birds to the effects of the avian irritant oaminoacetophenone. Aspirin and aspirin‐like drugs tended to desensitize starlings to the aversive effects of acetophenone bird repellents. Because the modulation mechanisms for the perception of pain appear to be similar in birds and mammals, the taxonomic differences in the perception of stimuli as irritating is inferred to be due to differences in receptor mechanism. The differences in sensory perception of chemical irritants has important implications for vertebrate foraging ecology and the evolution of plant‐animal interactions. © 1995 Wiley‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of

ISSN:0022-104X    

DOI:10.1002/jez.1402710604

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractGenotypes of early embryos obtained from matingBh/+ quail were determined by chorio‐allantoic membrane grafting of their thigh skin, and the development of TheBhhomozygous embryos was examined histologically. TheBhhomozygous embryos died at an early stage of development (after 7 to 10 days of incubation) with a very high incidence of whole‐body hemorrhage (approximately 100%), but malformation of neural tubes was not always accompanied byBhhomozygosity. Degeneration of the liver was more frequently observed in homozygous embryos than in wild‐type and heterozygous embryos. The results suggest that theBhgene causes whole‐body hemorrhage and subsequent death of homozygous embryos. In addition, our data indicate thatBhhomozygote would develop brown feathers on theirskin if they were able to survive. © 1995 Wiley

ISSN:0022-104X    

DOI:10.1002/jez.1402710605

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe fluids from healthy growing follicles of water buffalo were previously found free of the polypeptides H (Mr 36,000) and L (Mr 21,000) which were instead detected in fluids from atretic follicles and blood. Here we report evidence that these two polypeptides, as selected from serum by specific anti‐L antibodies, are the subunits of an oligomeric protein. The protein was purified from serum or follicular fluid, and its molecular weight (240 kDa), isoelectric point (6. 5), and amino acid composition were determined. The NH2‐terminal sequences of the subunits L and H were analyzed: 100% and 90% homology with α and β chains of bovine haptoglobin, respectively, was found. Thus, haptoglobin can be used as a novel molecular marker to assess the physiological state of the blood‐follicle barrier or discriminate between atretic and healthy follicles. © 1995 Wiley

ISSN:0022-104X    

DOI:10.1002/jez.1402710606

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractSperm of secondary male groupers(Epinephelus tauvina), derived from females implanted with 17α‐methyltestosterone (MT), were incubated with [3H]17‐hydroxyprogesterone for 2 hr. The medium was extracted and analyzed by high performance liquid chromatography (HPLC). A single major metabolite with relative retention time corresponding to 17α, 20β‐dihydroxy‐4‐pregnen‐3‐one (17,20α‐P) was produced by the sperm. The metabolite was isopolar with 17, 20α‐P on thin layer chromatography (TLC). The presumptive identify of the metabolite was confirmed to be 17, 20 α‐P when the metabolite was oxidised by periodic acid and the derivative recrystallized with authentic androstenedione to specific constant activity. This experiment indicates that grouper sperm possess the enzyme, 20α‐hydroxysteroid dehydrogenase (20 α‐HSD), and suggests that 17, 20 α‐P may play a role in grouper re

ISSN:0022-104X    

DOI:10.1002/jez.1402710607

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThree experiments were conducted to determine whether avian egg yolks contain the sex steroid 17β‐estradiol and whether experimentally produced elevations in maternal estradiol alter yolk estradiol and influence sexual differentiation of the offspring. The yolks of eggs laid by Japanese quail (Coturnix japonica) were found to contain significant amounts of estradiol comparable to those in the maternal circulation. Treatment of laying females with estradiol benzoate (EB) resulted in elevated yolk estradiol and a permanent morphological alteration of female off‐spring in the form of an increased incidence of right oviducts in adulthood. Such maternal transfer of a sex steroid to the egg yolk constitute a potentially significant source of maternal influence over embryonic development and adult phenotype in oviparous species. © 1995 Wiley‐Li

ISSN:0022-104X    

DOI:10.1002/jez.1402710608

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

ISSN:0022-104X    

DOI:10.1002/jez.1402710601

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY