摘要:

Histological observations were made to reveal the origin of young brooded in the enteron of adultActinia equinafrom Japan. A total of 295 specimens were collected from four rocky intertidal areas of Sagami Bay and eastern Suruga Bay, Pacific coast of Japan, during the period from February 1994 to January 1995. In the enteron of adults, regardless of sex, 910 young individuals were found. Among them, blastulae with a structure resembling a syncytial blastoderm were found. Development of blastulae to young with tentacles was inferred. Early embryos were observed in both sexes all year round, although the spawning season ofA. equinafrom Japan was restricted to early summer. This observation suggests that early embryos observed during the non-spawning season are produced asexually. Somatic embryogenesis is suggested as the mode of asexual reproduction ofA. equinafrom Japan because of the existence of blastulae in the enteron of anemones in both sexes.

ISSN:0792-4259    

DOI:10.1080/07924259.1999.9652362

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Monoclonal antibodies specific toPenaeus monodonvitellin and vitellogenin were produced using crude ovarian extract from gravidP. monodonovaries. After immunization and fusion of mouse spleen cells with P3X myeloma, hybridomas were selected by indirect immunoperoxidase ELISA againstP. monodonovarian extract, followed by dot-blotting against native and denatured proteins from ovarian extract, female haemolymph, and male haemolymph. Four hybridoma clones producing antibodies (PMV-11, 15, 22 and 64) were identified. They bound with ovarian extract proteins and with female haemolymph, but not with male haemolymph. One antibody (PMV-64) bound with both native and denatured proteins. Using Western Blot analysis of ovarian extract separated by PAGE, all four monoclonal antibodies bound with the same lipoglycoprotein band. Using Western Blot analysis of proteins separated by SDS-PAGE, PMV-64 antibody bound with Mw 80 and 83 kD proteins in ovarian extract, and with Mw 83 and 200 kD proteins in female haemolymph. All four monoclonal antibodies belong to the IgG1 subclass.

ISSN:0792-4259    

DOI:10.1080/07924259.1999.9652363

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

(Z)- and (E)-narains, 3,4-dihydroxystyryl sulfates, have been isolated from a marine spongeJaspissp. as inducers of larval metamorphosis in the ascidianHalocynthia roretzi(Tsukamoto et al., 1994a, 1994b). Subsequently, we found that narains inhibited hatching inH. roretziat concentrations of 10–50 μM, but did not affect trypsin-like protease activity which is released during larval hatching. Isolated chorion was dissolved by crude hatching enzyme solution and by commercially available trypsin from bovine pancreas. In both cases, dissolution of the chorion was inhibited by narains. Furthermore, the follicle cells surrounding the chorion of narain-treated embryos became condensed. These results suggest that narains do not inhibit hatching enzyme activity but rather affect the envelope of the embryo, resulting in inhibition of hatching.

ISSN:0792-4259    

DOI:10.1080/07924259.1999.9652364

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Time-lapse video microscopy, fluorescence microscopy, and electron microscopy provide complementary perspectives on the genesis and movements of the serosa, amnion, and yolk cells of the Indian meal moth,Plodia interpunctellaHübner (Lepidoptera: Pyralidae). Prospective serosal cells undergo a nuclear division, round up and detach from the adjoining cells of the germ band. They reattach only to other serosal cells, creating a free migrating edge at the boundary between the germ band and the serosa. The serosa engages in epiboly, spreads to enclose the embryo, attaches to the vitelline envelope, and secretes materials onto the vitelline envelope on the inner side of the egg shell. The amnion derives from the dorsal edge of the germ band; at this time the germ band is a cell sheet composed of columnar cells (palisade-type). Amniotic cells change briefly into spindle-shaped, motile cells that dissociate from the germ band. They cross the dorsal rim of the germ band, then flatten and form an epithelium. The amnion engages in epiboly and spreads across most of the embryo, starting approximately 1h after the serosa does. A lamina is secreted between the amnion and the embryo. By mid-embryogenesis, the amnion reaches over the dorsal region, including some yolk cells. The lamina and amnion loosen from the embryo during blastokinesis, the stage after germ band shortening. The yolk endoplasm partitions into yolk cells between 1 to 2h after other cells appear. Yolk cells are highly motile during early embryogenesis, then gradually slow and engage in cell shape changes without locomotion. They tend to flatten and ruffle during blastokinesis. By the end of blastokinesis, they form stable membrane contacts, creating a cell sheet. These large cells exhibit fountanoid and centripetal flows when they are motile.

ISSN:0792-4259    

DOI:10.1080/07924259.1999.9652365

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Micro- and macrospermatozoa were found in the male genital duct and female spermatheca ofScolopendra cingulata(Scolopendromorpha), whereas sperm dimorphism was not encountered inHimantarium gabrielis(Geophilomorpha). On the basis of ultrastructural analysis, the micro-and macrosperm ofS. cingulataand the single sperm type ofH. gabrielisappear functional. They are very long, filiform cells with all the morphological parts characterizing chilopodan sperm: (1) a spiral head surmounted by an acrosome containing actin, (2) a long linear tail consisting of a 9+2 axoneme surrounded by a striated cylinder and mantle. However, the dimorphic sperm differ in nuclear size, nuclear helix, chromatin condensation, and specificity for a fluorescent nuclear dye (Hoechst 33258). The fluorescent dye stained the nuclei of the microsperm ofS. cingulataand the single sperm type ofH. gabrielis, but it did not stain the nucleus of the macrosperm ofS. cingulata.On the basis of these differences, sperm dimorphism in Scolopendromorpha seems to have a functional significance. The microsperm may be active for fertilization, whereas macrosperm may have trophic or supporting activity.

ISSN:0792-4259    

DOI:10.1080/07924259.1999.9652366

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

In the terrestrial CrustaceanArmadillidium vulgare, the onset of female reproduction can be sped up by a male-induced stimulation. This male-effect is mainly characterized by a shortening of the vitellogenesis period, which occurs during the preparturial intermoult. The determinism of this phenomenon, for the first time reported by Jassem in 1982, was investigated here by both experimental and ethological approaches. It was shown that a male deprived of its copulatory organs is significantly less stimulating than an integrated one. On the other hand, a paired female with obturated genital apertures is significantly less stimulated. According to the literature, mating takes place only when vitellogenesis is nearly over and therefore cannot be related to the male-effect. Nevertheless, the ethological approach has revealed that females are early attractive for males, and that mating postures can be observed during the whole preparturial intermoult. In fact, insemination can happen as early as the initiation of the secondary vitellogenesis. Before this stage, short mating postures are still observed but no sperm was found in the female genital ducts (pseudocopulation). However, spermatozoa and other seminal substances are not implicated in this phenomenon since a male unable to ejaculate is as efficient as a normal one. Therefore, it is strongly assumed that the male-effect results from mating postures during which male copulatory organs act on mechanoreceptors located in the female genital apparatus.

ISSN:0792-4259    

DOI:10.1080/07924259.1999.9652367

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

TheReticulitermes lucifugusovary consists of about 40 panoistic ovarioles. A transverse septum between the terminal filament and germarium is absent, where two successive developmental stages of oogonia are recognizable. Early meiotic oocytes with synaptonemal complexes and nuclear vacuoles characterize the prophase region. Previtellogenic oocytes first show microvilli and later, in the cortical ooplasm, endocytotic vesicles about 70nm in diameter. Small yolk spheres and 120nm coated vesicles characterize early vitellogenic oocytes, while 180nm vesicles prevail in mid- and late vitellogenesis. The observations support heterosynthetic yolk production and endocytosis of yolk precursors. Prefollicular cells surrounding oogonia and early meiotic oocytes have a scarcely differentiated cytoplasm. Around early previtellogenic oocytes, follicular cells build a monolayered epithelium, first flat then cuboidal and release a granular material on the oocyte side. They closely adhere to each other and extend microvilli interdigitating with those of the oocyte. During vitellogenesis they are first columnar then globose and show large intercellular spaces which disappear in the final stage of vitellogenesis when they again become flat. Follicular cells apparently regulate transfer of materials for oocyte growth and after vitellogenesis synthesize egg envelope precursors. During choriogenesis they show an extended proteosynthetic apparatus whose products are exocytosed on the egg-facing surface and, after choriogenesis, produce a finely granular matrix covering the egg, easing oviduct transit and binding together newly laid eggs. The postovulatory follicle becomes the “corpus luteum” composed of degenerating, non-steroidogenic cells.

ISSN:0792-4259    

DOI:10.1080/07924259.1999.9652368

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Vitellogenin synthesis was investigated in the ixodid tick,Ixodes scapularis.The fat body was the most active tissue in vitellogenin production. Midgut and ovarian tissues showed slight activity (~2000 cpm) which may have been due to a small amount of contamination by fat body cells. Proteins synthesized by the fat body were examined and confirmed as vitellogenin by electrophoresis and audioradiography. There were seven radioactive polypeptides corresponding to the subunits of vitellogenin. Immunochemical analysis showed a strong reaction with anti-vitellin antibody in the fat body and developing ovaries; however, no specific fluorescence was seen in the midgut. These results indicate that the fat body is the main and probably the only site of vitellogenin synthesis in this prostriate tick.

ISSN:0792-4259    

DOI:10.1080/07924259.1999.9652369

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:0792-4259    

DOI:10.1080/07924259.1999.9652370

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:0792-4259    

DOI:10.1080/07924259.1999.9652361

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor