摘要:

Neck-ligated and thorax-ligated post-feeding (day 4) (last instar larvae ofSpodoptera mauritiawere treated with ecdysterone alone or in combination with a juvenile hormone analogue, hydroprene. The effects of these treatments on larval-pupal transformation were studied.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672197

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Genital imaginal discs were dissected fromHeliothis virescenspupae just after diapause break and culturedin vitro.The discs continued to grow and differentiate when maintained in media containing sufficiently high titers of 20-hydroxyecdysone (20HE) and co-cultured fat body or testis sheath tissue, or extract of fat body previously exposed to 20HEin vitro.Continuous changes were observed for approximately 30 days. Other tissues provided only temporary (5–8 day) developmental support. Genetal discs did not develop in the absence of 20 HE. Discs co-cultured with fat body in 20 HE medium synthesized more protein and DNA than discs co-cultured with fat body but without 20 HE. Fat body and testis sheath tissue, cultured with sufficient titers of 20 HE, produced factors essential to the development of genital imaginal discs ofH. virescens.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672198

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The male accessory reproductive glands (ARG) ofChilo partellusshow the presence of certain protein fractions which are immunologically identical with larval haemolymph proteins (LHPs). The uptake of radiolabelled haemolymph proteins obtained from the mid-last instar larvae by the male ARG has been studied here. The results show that the ARGs sequester both the LHPs (LHP 1 and LHP 2)in vitroand this uptake is stimulated by 20-hydroxyecdysone as well as by its agonist, RH 5849. When the ARGs are co-cultured with35S methionine-labelled fat body of mid-last instar larvae in the presence of 20-hydroxyecdysone, there is an increased uptake of LHPs along with a few other polypeptide fractions.In vitroculture of ARG followed by fluorographic analysis reveals that the ARGs synthesise large number of polypeptides but those which co-migrate with the LHPs are absent.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672199

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The ecdysteroid composition of embryos ofM. rosenbergiiat various stages of embryogenesis has been studied by means of radioimmunoassay (RIA), high-performance liquid chromatography—RIA (HPLC-RIA) and gas chromatography/mass spectrometry (selected ion monitoring; GC/MS(SIM). In newly-laid eggs, only free ecdysteroids (ecdysone and 20-hydroxyecdysone) were detected, whereas eggs at an early stage of embryogenesis contained ecdysone and also low levels of apolar ecdysteroid conjugates. Mid stage embryonating eggs contained comparatively high levels of both free ecdysteroid (ecdysone, 18.3 ng/g) and apolar conjugates (29.9ng/g). Late embryos contained by far the highest overall level of ecdysteroid, indicating the ability of the developing embryo to synthesize ecdysteroid. In contrast to the other stages, late embryos contained 26-hydroxyecdysone, ecdysonoic acid and 20-hydroxyecdysonoic acid at relatively low levels and 2, 3-diacetylecdysone 22-phosphate at a comparatively high level (324.0 ng/g). These results suggest that the developing embryo ofM. rosenbergiiis capable of both ecdysteroid biosynthesis (presumably for utilization during specific stages of embryogenesis), conversion into apolar conjugates and inactivation by conversion into 26-oic acids and polar conjugates.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672200

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The ultrastructure of the mature spermatozoon and spermiogenesis of the bivalveCallista chione(Heterodonta, Veneridae) are described.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672201

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Methyl farnesoate (MF) expression and reproductive system size were compared in five representative groups of maleL. emarginataselected from a sample collected in November. The groups differed from each other with respect to carapace size (small, intermediate and large), relative propodus size (small and large claw forms), and condition of the exoskeleton (abraded and unabraded). Large males with large claws and abraded exoskeletons had reproductive system indices which were significantly larger than any other group. The mandibular organs of these crabs also had significantly higher rates of methyl farnesoate synthesisin vitro.Hemolymph titers of methyl farnesoate were also highest in this group, but were not significantly different from the group with small carapaces, small claws and unabraded exoskeletons. Methyl farnesoate titers were significantly lower in all other groups of unabraded animals with small or large claws. These results suggest that methyl farnesoate may play a role in morphogenesis and reproduction in maleL. emarginata.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672202

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Ecdysteroid localization in target tissues ofDrosophila melanogasterwas demonstrated by the utilization of low temperature autoradiography and immunohistochemistry. Autoradiographic studies utilized high specific activity [3H]ponasterone A, an ecdysteroid with exceptional molting hormone activity inDrosophila.The data revealed a selective nuclear concentration of the labelled ligand in cells of the salivary gland, corpus allatum (source of juvenile hormone), prothoracic gland (source of ecdysone) and the central nervous system. Nuclear localization was also observed in epithelial cells of the esophagus and muscle cells of the pharynx and mandibles, etc. The specific labelling of cell nuclei was prevented by incubation of the tissue with [3H]ponasterone A in the presence of excess unlabelled ponasterone A. Nuclear localization of ponasterone A in the salivary gland was also observed when using an antiserum against ecdysteroids and an avidin-biotin-complex (ABC) detection system. The staining showed two binding patterns, heavy and light, that agreed with the autoradiographic studies. The results clearly demonstrate specific ponasterone A binding sites in nuclei of the target cells and support the dogma that ecdysteroids exert their effects at the level of the genome.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672203

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Luidia clathratafed a low food ration during the gametogenic period had a decrease in the weight of the body and pyloric caeca although gonads were produced. Individuals fed a high food ration during this period had an increase in the weight of the body and pyloric caeca along with gonad production. The eggs of individuals fed the low food ration were significantly although only slightly larger than those of individuals fed the high food ration. The eggs of the former group had a lower fertilizability (21 versus 100%) and a lower survival (50 versus 80%). This indicates that egg size inLuidia clathratais not greatly affected by food ration, and that egg size is not a good indicator of egg quality for this species. Life history models must consider the effect of food ration on the quality of eggs.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672204

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Adults of the conical snail,Cochlicella acuta, laid eggs in laboratory cultures from autumn to spring, with a peak in autumn-early winter. There was no evidence to suggest that large adults produced more eggs than small adults over the whole breeding season, nor that crowding of adults reduced production/snail when food was abundant. In experiments where snails were kept in pairs and size varied between pairs, an overall average of 7.1 clutches and 257.7 eggs per pair were produced during the laboratory breeding season. Where density of snails varied, an overall average of 9.2 clutches and 372.6 eggs per pair was recorded.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672205

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Proteins synthesized and accumulated during oogenesis orPseudopotamilla occelatawere analyzed by two-dimensional Polyacrylamide gel electrophoresis and fluorography. Significant changes in the patterns of synthesis and accumulation occur during oogenesis, paticularly between previtellogenic and vitellogenic stages, although many of the proteins are represented throughout the process. The changes may be generally dependent upon the variation in the gene expression affecting autosynthesis of proteins. However, appearance of proteins, which occur only at the vitellogenic stages but apparently not synthesized within the oocytes, indicates that heterosynthetic proteins are stage-specifically transported into oocytes.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672206

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor