ISSN:0792-4259    

DOI:10.1080/07924259.1989.9672054

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0792-4259    

DOI:10.1080/07924259.1989.9672055

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The nervous part of the locust corpora cardiaca (NCC) was extracted using 70% methanol and subjected to fast protein liquid chromatography (FPLC). Twenty fractions were collected and injected into females from the end of the IIIrd larval instar to day-12 of the adult life to screen the effects on metamorphosis, body pigmentation, and oocyte growth. The rate of juvenile hormone (JH) biosynthesis by the corpora allata of injected animals was evaluatedin vitro.One fraction was found to stimulate ovarian maturation, and 3 to delay oocyte growth. None of them disturbed (i) either metamorphosis and body color (which are JH dependent), or (ii) rate of JH biosynthesis. Of the 3 fractions which inhibited ovarian maturation, 2 of them were identified as the neuroparsins A and B. The results clearly illustrate that antagonist factors from the brain are involved in the regulation of ovarian maturation in the locust.

ISSN:0792-4259    

DOI:10.1080/07924259.1989.9672056

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The male cells in the ovotestis of hibernating snails undergo multiplication when the temperature of the environment is raised from 5°C to 25°C. If the temperature is maintained at 25°C for 4 weeks the process of spermatogenesis is completed but the rate of spermatogenesis (DNA synthesis) starts decreasing from the 3rd week (Table 1; Fig. 1).

ISSN:0792-4259    

DOI:10.1080/07924259.1989.9672057

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The mysidSiriella armataprovides a new biological model for investigations on the molting and reproductive physiology in crustaceans. The main endocrine centres (Y-organ, mandibular organ, androgenic gland, X-organ and sinus gland) have been described and are available for experimentation. Experimental cautery of Medulla Interna-Medulla Externa-X-organ-sinus gland complex (MI-ME-X-organ-SG) of the eyestalk inhibited molt and brood production demonstrating that the complex plays a role in regulation, at leastviaa positive action upon the circulating ecdysteroids. In the present paper, the results already obtained are reviewed and the perspectives offered by this biological model discussed in reference to other crustaceans.

ISSN:0792-4259    

DOI:10.1080/07924259.1989.9672058

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The present study deals with the location of the vitellogenesis inhibiting hormone (VIH)-producing cells in the eyestalk of the lobsterHomarus americanus.In the present study, the neurosecretory pathways of VIH in Homarus, have been described immunocytochemically by use of a mouse serum againstHomarusVIH. The location of the VIH cells was compared with the location of the crustacean hyperglycemic hormone (CHH) cells visualized by a rabbit serum raised against CHH of the crayfishAstacus leptodactylus.Immunocytochemical detection procedures, both at the light and electron microscopic level, revealed frequent but not complete co-localization of VIH and CHH in a variable number of the same group of perikarya. In the sinus gland, both neuropeptides were mostly demonstrated in distinct axonal endings characterized by different granule types. Postulations on the biosynthesis of these factors and suggestions concerning the processing of both neurohormones have been made.

ISSN:0792-4259    

DOI:10.1080/07924259.1989.9672059

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In polychaete annelids, two types of vitellogenesis have been described: a heterosynthetic mechanism (in a number of different of worms) and an autosynthetic process (other includingNereis). Recent biochemical results suggest that the heterosynthetic mechanism is more general than previously thought. InNereis, the vitellogenin (the precursor) is synthesized in coelomocytes and after transfer through coelomic fluid incorporated into oocytes. In germinal cells, a conversion process, involving proteolytic cleavages of vitellogenin, produces mature vitellins which are accumulated in yolk granules.

ISSN:0792-4259    

DOI:10.1080/07924259.1989.9672060

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Seasonal reproduction in terrestrial Isopods is regulated by a neurohormone (VIH) synthesized in neurosecretory cells located in the protocerebrum median part. VIH restrains vitellogenin synthesis by the fat body. This inhibitory system is driven by the photoperiodic variations. Long days introduce a decrease in synthesis and—or—VIH release, allowing the oocytes to carry out the last vitellogenic phase. Other signals (mating, eggs in brood-pouch) tune the activity of the inhibitory system. Various aspects of photoperiodic and neurohormonal controls of reproduction are discussed: geographical variability and genetic determinism of the photoperiodic response; chemical nature, specificity and VIH mode of action; male physiology and VE synthesis, modalities of VIH synthesis and release.

ISSN:0792-4259    

DOI:10.1080/07924259.1989.9672061

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The article summarizes the research carried out in Besançon on the stylommatophoran snailHelix aspersa, a pulmonate gastropod mollusc.

ISSN:0792-4259    

DOI:10.1080/07924259.1989.9672062

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

We have analysedin vitrothe effect of farnesylacetone, a substance produced by the androgenic gland of Crustacea, in a concentration of 20 ng/ml, on the protein synthesis in the ovary ofCarcinus maenas.In winter, the farneslyacetone seems to be ineffective; the incorporation of labelled precursor per mass unity is then related to the weight of the sample. In summer, an activation of protein synthesis can be observed. These results do not depend on ovary maturation and concern all the proteins of the gonad.

ISSN:0792-4259    

DOI:10.1080/07924259.1989.9672063

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor