摘要:

AbstractThe control of synthesis of the two prolactins (tPRL188and tPRL177) in the anterior‐most portion of the pituitary, the rostral pars distalis (RPD), was investigated in freshwater (FW)‐ and seawater (SW)‐ acclimated tilapia. Individual RPD of FW and SW male tilapia were incubated in either hyposmotic or hyperosmotic medium containing3H‐leucine for various intervals, up to 360 min. The total quantity of the two tPRLs in media and RPD was assessed by gel electrophoresis and scanning densitometry of the stained bands. Synthesis was characterized as the uptake of3H‐leucine into the tPRL molecules. Results showed greater synthesis and release of both3H‐tPRLs in the RPD from FW tilapia than in those from SW‐ acclimated tilapia. The in vitro synthesis of both prolactins tPRLl88and tPRL177in RPD of FW tilapia and tPRLl77in RPD of SW fish was also augmented by exposure to hyposmotic medium. The ratio of the appearance of newly synthesized3H‐ tPRLl88:3H‐tPRL177was approximately 1.3 in FW tilapia RPD and approximately 0.5 in SW tilapia RPD. The delay between effect of osmotic pressure on tPRL release and its effect on tPRL synthesis suggests that the rapid effect of osmotic pressure upon PRL release is at least partially independent of its effect upon tPRL synthesis. Moreover, the altered ratios of tPRL188and tPRL177observed in our studies suggest that the synthesis rates of the two tPRLs are differentially sensitive to environmental salinity. © 19

ISSN:0022-104X    

DOI:10.1002/jez.1402710502

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe body surface mucus from the land slug,Incilaria fruhstorferi, not only opsonized sheep red blood cells (SRBC) and agglutinated human types A and B erythrocytes (HRBC) but also caused hemolysis of B type HRBC 12 h after agglutination. The mucus‐induced hemagglutination was specifically inhibited by a low concentration of N‐acetyl D‐galactosamine (GaINAc), and all of this activity was completely inactivated by heating at 56°C for 30 min. SDS‐polyacrylamide gel electrophoresis of water soluble fraction of the mucus showed that this fraction contained several proteins, the molecular mass of the main band being 35 KD. © 1995 Wiley

ISSN:0022-104X    

DOI:10.1002/jez.1402710503

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe myoplasm of the ascidian egg contains muscle determinants and is composed of myoplasmic cytoskeletal domain (MCD). MCD consists of two interacting parts, a plasma membrane lamina (PML) and a deep filamentous lattice (DFL). We showed that, among the four types of egg fragments that are produced by centrifugation of unfertilizedCiona savignyieggs, muscle determinants are concentrated in only one type (black fragment) and are virtually absent in the others (clear, brown and red fragments). In this study, to investigate the relationship between MCD and muscle determinants, we compared the distribution of PML and DFL among the egg fragments. Actin filament, which is a component of PML, was found in all fragments. In contrast, p58, which is a protein recognized by an anti‐intermediate filament antibody and is a component of DFL, was highly concentrated in black fragments and excluded from the other three. In addition, pigment granules and mitochondria, both of which are embedded in DFL, were also concentrated in black fragments. Thus, the distribution of muscle deteminants among the egg fragments coincided with that of DFL, supporting the possibility that muscle determinants may be associated with DFL rather than with PML. © 1995 Wiley‐Liss,

ISSN:0022-104X    

DOI:10.1002/jez.1402710504

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

年代:1995

数据来源: WILEY

摘要:

AbstractAn enzymatic method for removing embryo‐toxic ammonium from culture medium has been developed. Ammonium, produced by both embryo metabolism and spontaneous breakdown of amino acids at 37°C, is transaminated by glutamate dehydrogenase to nontoxic glutamate. Initially, the individual components of the transamination reaction were titrated against mouse embryo development in vitro to determine embryo‐safe levels. ADP, an allosteric activator of glutamate dehydrogenase, was found to inhibit embryo development and was therefore omitted from the final formulation (α‐ketoglutarate, 0.44 mM; glutamate dehydrogenase, 0.375 U; NADH, 0.12 mM). It was found that 0.30 mM ammonium could be removed from the culture medium in situ in 3 h. In situ removal of ammonium significantly increases both blastocyst cell number, implantation, fetal development, and fetal weight after transfer. Removal of ammonium by the conventional method of renewing the culture medium also increased blastocyst cell number but did not affect postimplantation development. In conclusion, it is possible to alleviate the toxic effects of ammonium in vitro on pre‐ and postimplantation mouse embryo development by its transamination in situ. Thereby facilitating the continual exposure to embryo‐derived factor(s) which stimulates both pre‐ and postimplantation development. © 1995 W

ISSN:0022-104X    

DOI:10.1002/jez.1402710505

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe determine the site of vitellin (Vn) synthesis in the blue crab,Callinectes sapidus, tissues (ovary, hepatopancreas, and gill) from adult female crabs were incubated in vitro with [35S]methionine. Tissue extracts were separated by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and radiolabeled proteins were visualized by autoradiography: Four radiolabeled ovarian proteins (188, 168, 109, and 86 kDa) comigrated with the subunits of Vn. A Western blot analysis confirmed that these ovarian proteins were the Vn subunits. Proteins in the hepatopancreas and gill were also radiolabeled but were not Vn‐immunoreactive. In vitro incorporation of [35S] methionine into ovarian proteins was inhibited by an extract of eyestalks; the inhibition was dose‐dependent and specific. Autoradiography of the electrophoretically separated ovarian proteins revealed that the eyestalk extract inhibited incorporation of [35S] methionine into numerous proteins, including the Vn subunits. These results suggest that the ovary is a site of Vn synthesis and that the eyestalks contain a factor or factors that directly inhibit the synthesis of Vn and other ovarian proteins. It is anticipated that the suppression of ovarian protein synthesis will be a useful bioassay for blue crab vitellogenesis‐inhibiting hormone. © 1995 Wiley

ISSN:0022-104X    

DOI:10.1002/jez.1402710506

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

年代:1995

数据来源: WILEY

摘要:

AbstractSuspensions of cells obtained from genital ridges and gonads of bovine embryos of 1.0‐3.4 cm in crown‐rump (C‐R) length were used for studies of the metabolism of radiolabeled exogenous steroid precursor. Tritiated androstenedione was employed as precursor and the final products of their metabolism were evaluated after separation by thin‐layer chromatography. Genetic sex was determined by the karyotype of hepatocytes from the same embryos. The extent of conversion of tritiated androstenedione was higher in cells from male embryos than cells from female embryos. Furthermore, androstenedione was metabolized mainly to testosterone in male embryos. By contrast, cells obtained from female embryos transformed androstenedione to estrone and 17β‐estradiol. The onset of this activity was observed at 1.8 cm in C‐R length in males and at 2. 2 cm in C‐R length in females. In all cases, after the onset, the metabolic activity increased in relation to the age of the embryos. These data show that in the bovine embryo gonad, the activity of aromatase and 17β‐hydroxysteroid dehydrogenase are present when the morphological differentiation of the gonadal sex has not yet been established. © 19

ISSN:0022-104X    

DOI:10.1002/jez.1402710507

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

年代:1995

数据来源: WILEY

摘要:

AbstractMost species of the viviparous teleost family Goodeidae exhibit an unusual placental relationship. Embryos lay free within the single, hollow ovary where they are bathed by the ovarian fluid. Nutrients are absorbed from the fluid through distinctive perianal processes called trophotaeniae. Trophotaeniae represent the embryonic component of the placenta and may be functionally divided into protein endocytosing and nonendocytosing types. The maternal component of the placenta is the internal ovarian epithelium (IOE). Since embryos undergo dry weight increases ranging from 68‐ to 387‐fold compared to the dry weight of mature ova, there must be substantial nutrient transfer from the maternal organism during gestation. Transmission electron microscopy of the IOE of gravid females of three goodeid species fails to reveal evidence of significant synthetic activity by the IOE, although occasional budding of parts of IOE cells occur, and the IOE of one species, G.atripinnis, contains substantial amounts of lipid. Electrophoretic comparison of nongravid females of two species establishes that the protein pattern of the ovarian fluid is similar to that of the female blood serum. In gravid females whose embryos bear protein‐endocytosing trophotaeniae, protein is undetectable in the ovarian fluid during mid‐ and late gestation, suggesting efficient protein absorption by the trophotaeniae. In gravid females whose embryos bear nonendocytosing trophotaeniae, serum proteins are present in the ovarian fluid at midgestation, but are reduced to only a trace at late gestation suggesting possible imbibition by the embryos. © 1995 Wiley

ISSN:0022-104X    

DOI:10.1002/jez.1402710508

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

年代:1995

数据来源: WILEY

摘要:

AbstractOvarian explants from the red swamp crayfish,Procambarus clarkii, were incubated with 5‐hydroxytryptamine (5‐HT) and muscle, and with 5‐HT in combination with eyestalk tissue, brains, or thoracic ganglia. In vitro, 5‐HT without brain or thoracic ganglia in the incubation medium had no significant effect on the ovarian explants. In contrast, in vitro brains and thoracic ganglia induced ovarian maturation, indicating the presence of a gonad‐stimulating hormone (GSH) in these tissues. However, this in vitro stimulatory effect was significantly greater when 5‐HT was present in the incubation medium with the brains and thoracic ganglia. These results provide in vitro evidence in support of the hypothesis that the previously observed in vivo stimulatory action of 5‐HT on the ovaries is an indirect one, 5‐HT acting to stimulate release of a GSH. © 1995

ISSN:0022-104X    

DOI:10.1002/jez.1402710509

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

年代:1995

数据来源: WILEY

摘要:

AbstractBlue crab ovaries rapidly increased in weight during the 30 days after the terminal molt into adulthood. Oocytes isolated from ovaries during this period increased in diameter from 40 to 201 μm. The concentrations of lipovitellin, a high density lipoprotein found in oocytes, were determined by a competitive ELISA procedure using a monoclonal antibody against one of the lipovitellin peptides. Lipovitellin and lipid droplets were minor components in the immature ovaries and oocytes but increased in concentration to become the major components of the mature ovaries and oocytes. In mature oocytes (201 μm diameter) lipovitellin concentrations accounted for 35 and 95% of the total oocyte protein and soluble oocyte protein, respectively. In mature oocytes the total lipid, lipovitellin lipid, and lipid droplet concentrations were 510, 240, and 140 ng/oocyte, respectively. Sections of ovaries and hepatopancreas at different stages of maturation were probed with the anti‐lipovitellin antibody. In small immature oocytes, where no yolk was present, the immunoreactivity was confined to perinuclear yolk complexes. The immunoreactivity of more mature oocytes was associated with globular structures in the cytoplasm. Neither ovarian follicle cells nor hepatopancreas cells showed immunoreactivity. Our results suggest that in blue crabs the lipovitellin components are primarily synthesized in the developing oocytes with perinuclear yolk complexes playing an important role in the formation of lipovitellin‐rich yolk granules. Scattered collections of presumed phagocytic hemocytes contained immunoreactive granular material in their cytoplasm. We suggest that these hemocytes remove debris from oocytes which fail to reach maturation and carry this debris to the hepatopancreas. © 1995 Wiley‐L

ISSN:0022-104X    

DOI:10.1002/jez.1402710510

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.1402710501

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

年代:1995

数据来源: WILEY