摘要:

AbstractThe output of ammonia increases in dilute waters in which blue crabs absorb Na+against a gradient, but not those in which crabs remain in salt balance with the medium. Net acid output does not clearly vary with salinity. The balance between ammonia and urea output shifts towards ammonotelism at low salinity. These results, and the temporal responses of blood NH4+, Na+and Cl‐after a salinity change, support the hypothesis that excess ammonia in blood plays an important role in osmoregulation as well as opposing the effect of salt reduction on the oxygen transport syste

ISSN:0022-104X    

DOI:10.1002/jez.1401950112

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

年代:1976

数据来源: WILEY

摘要:

AbstractAcrosome reactions occurring in vitro in hamster sperm capacitated by bovine follicular fluid were severely inhibited by four synthetic trypsin inhibitors and by Zn2+. Three polypeptide trypsin inhibitors and a synthetic chymotrypsin inhibitor did not inhibit the acrosome reaction, and Ca2+ overcame the inhibition by Zn2. These results suggest that a trypsin‐like enzyme (possibly acrosin) plays a role in the acrosome reactio

ISSN:0022-104X    

DOI:10.1002/jez.1401950113

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

年代:1976

数据来源: WILEY

摘要:

AbstractSpongilla lacustris exhibits a type of alternative hermaphroditism, new to the phylum, in which a sponge may be exclusively male or female during the period of sexual reproduction one year and the opposite sex the next year. This form of sexuality may facilitate larva production and thus dispersal following colonization of a new habitat. Gametogenesis occurs shortly after gemmule hatching in both males and females but slightly later in males.

ISSN:0022-104X    

DOI:10.1002/jez.1401950114

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

年代:1976

数据来源: WILEY

摘要:

AbstractOocytes were collected from preantral follicles (200–300 μ in diameter) from 30‐day‐old immature rats 7 days after hypophysectomy. The ova were cultured in vitro for 17 hrs in a chemically defined medium and scored cytologically for meiotic maturation. Of 534 oocytes that were cultured 89% resumed meiosis; however, 98% of these oocytes arrested in either metaphase or anaphase I. In contrast, 82% of the oocytes isolated from preovulatory follicles (∼600 μ in diameter) of adult proestrus rats progressed to metaphase II. These results are discussed in terms of functional FSH and LH receptors on the granul

ISSN:0022-104X    

DOI:10.1002/jez.1401950115

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe lantern of the adult firefly is innervated by a nerve supply with endings similar to other known monoaminergic nerves. However, catecholamines could not be detected in the nerve endings and noradrenaline and adrenaline were relatively weak agonists in eliciting a flash of light when applied to the lantern in vitro. Firefly lanterns were assayed for octopamine using a sensitive, specific enzymatic assay in which octopamine is enzymatically converted to3H‐synephrine and quantitated by liquid scintillation counting. The presence of substantial amounts (125 ng/g tissue) of octopamine was demonstrated and confirmed by thin layer chromatography. On the basis of this and earlier work, it is suggested that the nerves to the firefly lantern are octopaminergi

ISSN:0022-104X    

DOI:10.1002/jez.1401950116

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

年代:1976

数据来源: WILEY

摘要:

AbstractExtracts of the pericardial organs of crabs injected into intact animals cause an increase in the frequency of scaphognathite beating. The active factor is not dopamine or 5‐hydroxytryptamine, which are present in pericardial organs; it is probably a peptide. The factor may represent a hormonal mechanism of coordinating heart rate and ventilatio

ISSN:0022-104X    

DOI:10.1002/jez.1401950117

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe contents of free adenylate nucleotides (ATP, ADP and AMP) were measured in the earthwormEisenia foetidaat different levels of the body, at various stages of regeneration. The nucleotide concentrations are highest in normal segment 9. AMP level decreases anteroposteriorly. In the first days of cephalic regeneration characterized by DNA synthesis the level of AMP decreases. Conversely AMP level increases during caudal regeneration. The nucleotide AMP might be the substance which specifically inhibits cephalic regeneration.

ISSN:0022-104X    

DOI:10.1002/jez.1401950118

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

年代:1976

数据来源: WILEY

ISSN:0022-104X    

DOI:10.1002/jez.1401950101

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

年代:1976

数据来源: WILEY