中华稻蝗卵子卵黄发生期超微结构研究

利用透射电镜研究了中华稻蝗Oxya chinesis卵子发生中卵黄发生期的超微结构.卯黄发生初期,滤泡上皮细胞胞质内出现大量粗面内质网及线粒体等细胞器,可能与为卵母细胞提供营养有关.卵黄发生期卵母细胞胞质内卵黄球逐渐增多,它也许有多种来源.观察到环形片层结构,并讨论了其可能功能.     

Activation of egg production and the corpus allatum without feeding in the adult female of the insect Rhodnius prolixus

Summary

In unfed virgin or mated females of Rhodnius prolixus, a proportion of females makes some eggs. Vitellogenesis in this prefeed period resembles closely that in fed females: it involves the activation of follicle cells, the development of spaces between the follicle cells, and a dependency on the corpus allatum and juvenile hormone. It is concluded that juvenile hormone is normally secreted in the period between emergence and the first adult blood meal. Eggs are produced only if sufficient blood remains in the crop from the previous larval meal. The data concerning crops size are consistent with the hypothesis that the activity of the corpus allatum is governed by the degree of distension of the crop or abdomen.     

锯缘青蟹卵黄发生期卵母细胞和卵泡细胞之间的结构变化

通过电镜研究了锯缘青蟹二次卵巢发育过程中卵黄发生期（分为初期和后期）卵母细胞表面的结构和胞质的变化。卵黄发生初期分为：内源性卵黄发生阶段和有卵泡细胞直接参与的外源性卵黄合成阶段,前者特征为：在卵母细胞中充满了内质网泡,在泡内有不同程度的卵黄物质合成,此时在卵母细胞的表面区域,可见很多卵泡细胞向卵母细胞表面迁移,并包围卵母细胞。后者其特征是在卵母细胞的表面,有大量的胞饮小泡出现在卵膜的内面,随着两细胞表面膜的逐步融合和胞饮作用加强最后形成链锁状结构,胞质中靠近卵质周围有卵黄体的积极合成和大更换 脂肪滴积累,在此阶段的后期,卵泡细胞质已基本吸收完毕,卵泡细胞膜和卵母细胞膜融合,某些界面已无膜结构。卵黄发生后期在亲蟹孵出幼体后的第11d至第27d基本结束,此期也主要以外源性卵黄发生为主,在卵母细胞的周围,卵泡细胞迅速扩大,其间分布着大量的大小不同的囊泡和线粒体,在接近卵母细胞表面,还常可见大量的脂肪滴存在。卵泡细胞与卵母细胞间其膜结构完全消失,从而可使滤泡大片细胞质直接融入卵母细胞中,以后随着卵黄发生的进一步发展,卵母细胞与卵泡细胞的交界面逐步形成一个网状的膜结构屏障,同时在卵巢中可见正在降解的卵母细胞,在卵黄发生近结束以后,在卵母细胞的表面,逐步形成两层卵膜,这时的卵母细胞质中几乎充满了卵黄体和脂肪滴。     

Vitellogenic and embryogenic activity of the microtubule disruptor vinblastine following ingestion by the wasp Bracon hebetor

The reproductive performance of Bracon hebetor females was adversely affected by the consumption of sub-lethal doses of vinblastine. While all oögenic cell types present in the gonads at the time of treatment displayed various degrees of fecundity and/or fertility depression, the transitional cells proved to be the least susceptible to vinblastine damage. Vitellogenically active oöcytes were most sensitive to vinblastine. In these oöcytes development was blocked at or prior to the terminal growth phase. Oviposited eggs which did arise from the exposed vitellogenic oöcytes were few in number and characterized by aberrant morphology. Embryogenic effects were predominantlydue to pre-blastoderm formation damage and most pronounced in oöcytes exposed during the most advanced stages of gonadal development, late vitellogenesis through meiotic metaphase I. Reduced egg hatchability also occurred in exposed undifferentiated oögonial cells but the effect was less severe than that seen in the more mature oögenic cells. All observed effects could be accounted for by vinblastine's selective interference with microtubule-dependent processes. Fecundity effects were most closely associated with oöcyte cortex and possibly follicular cell damage which prevented vitellogenic growth beyond the terminal growth phase. Fertility effects were caused by the inhibition of early embryonic karyokinesis with the most plausible target being mitotic spindle formation.     

Development of Vitellogenin-ELISA,an In Vivo Bioassay,and Identification of Two Vitellogenesis-Inhibiting Hormones of the Tiger Shrimp <Emphasis Type="BoldItalic">Penaeus monodon</Emphasis>

A sandwich enzyme-linked immunosorbent assay (ELISA) for the quantification of vitellogenin in the hemolymph of Penaeus monodon is reported. Lipovitellin from the mature ovary was purified using hydroxylapatite column chromatography and used as the standard protein, which was serially diluted from 3336 to 6.51 μg and gave a linear plot. Sensitivity results showed ELISA was insensitive to samples that did not contain vitellogenin or lipovitellin. Specificity results showed the degree of the discrimination of the assay between positive samples (having vitellogenin or lipovitellin) and negative samples (devoid of vitellogenin or lipovitellin). Reproducibility studies showed that the intraassay coefficient of variation was 5.1% (n= 11) and the interassay coefficient of variation was 5.15% (n= 13). Separation of X-organ sinus gland peptides using a reversed phase column gave a total of 37 fractions. Two fractions were found to reduce the hemolymph vitellogenin concentration in a time-dependent manner and could be identified as vitellogenesis-inhibiting hormones I and II. Received February 2, 2001; accepted June 24, 2001     

Lipophorin as a yolk precursor in Hyalophora cecropia: uptake kinetics and competition with vitellogenin

Vitellogenic follicles of Hyalophora cecropia were incubated in metabolically radiolabeled, high-density lipophorin isolated from pharate adult hemolymph by KBr density gradient centrifugation. The follicles transferred this probe from the incubation medium to the cortical yolk spheres in the oocyte by an energy-dependent and saturable mechanism. Vitellogenin and high-density lipophorin competed with each other for uptake, and are therefore concentrated by the follicle with a common mechanism. Microvitellin and lipophorin, in contrast, did not compete for uptake. The K(uptake) for the accumulation of high-density lipophorin was substantially higher than the value estimated earlier for vitellogenin (133 microM vs. 18 microM). This relationship helps explain why the shared concentrating mechanism does not deplete the lipid transport capacity of the hemolymph, and how a low vitellogenin: lipophorin molar ratio in the hemolymph yields a high ratio in the mature egg.     

Postendocytic vitellin processing in ovarian follicles of the stick insect Carausius morosus (Br.)

Newly laid eggs of the stick insect Carausius morosus contain two native vitellins (Vit A and Vit B). Under denaturing conditions, these vitellins resolved into 3 (A₁, A₂, and A₃) and 2 (B₁ and B₂) polypeptides. All of these polypeptides had counterparts in the female hemolymph from which they were shown to be derived by in vivo labelling. During ovarian development, the 2 vitellins changed both in charge and polypeptide composition. In EV and LV follicles, Vit A resolved into 4 distinct vitellin polypeptides (A₀, A₁, A₂ and A₃). Using a panel of monoclonal antibodies, polypeptide A₀ proved to be immunologically related to polypeptide A₂. In follicles about to begin choriongenesis, polypeptide A₃ was gradually replaced by a lower M_r polypeptide. Over the same time period, polypeptide B₁ changed in charge, but not in M_r. To confirm the existence of a polypeptide processing in C. morosus, ovarian follicles of different developmental stages were exposed in vivo to [³⁵S]-methionine from 6 to 72 h. Data showed that A₀ and B₁ were the polypeptides most heavily labelled after short time exposures to the radioisotope. Polypeptides B₂ and A₃ were also labelled to some extent. With progressively longer exposures, polypeptides A₁ and A₂ also became labelled. In vivo exposure to [³H]-GlcNAc caused all vitellin polypeptides to become heavily labelled. Autoradiographic analysis of ovarian follicles labelled this way showed that, during development, radioactivity was gradually transferred from newly formed yolk spheres in the cortical ooplasm to the central ooplasm. Data were interpreted as suggesting a causal relationship between polypeptide processing and progressive yolk sphere fusion to yield the central ooplasm. © 1993 Wiley-Liss, Inc.     

Behavior of symbionts during oogenesis and early stages of development in the German cockroach, Blattella germanica (Blattodea)

In this paper, adaptations and microanatomic changes in the branchial chamber, as well as influence of parasitosis on the reproductive function of shrimp, are analyzed. Probopyrus cf. oviformis was observed in the branchial chamber of shrimps of both sexes, with an infestation rate of 29%. The infestation frequency in relation to sex and size was not uniform, and two trends were observed: a higher frequency in bigger males in contrast to females, with less infestation frequency in older individuals. This aspect was related to changes in the sex ratio of shrimps, infested and noninfested, with the following conclusions: (1) Sexual inversions were not observed in females of P. argentinus; (2) male infestation with P. cf. oviformis showed tertiary sexual rate bias. It occurred because the metabolic parasite-host relationship led to an increase in size. These infested males were incorporated into a normal population characterized by females being bigger than males. The morphological and functional changes observed were (1) branchial chamber reduction, slendering of the cephalothorax lateral wall, together with local injury (oxygen consumption was below the normal values; and (2) the ovaries of infested females of P. argentinus remained stationary in incipient maturity (secondary vitellogenesis was not observed).     

Independently regulated juvenile hormone activity and vitellogenesis in mosquitoes

Temporally distinct, head-mediated processes regulate vitellogenic development as well as juvenile hormone (JH)-mediated development of ovarian follicles of Aedes aegypti. In blood-fed adult mosquitoes, vitellogenic development is stimulated during the first day after blood is imbibed and JH secretion is stimulated 2 days later. JH secretion in recently ecdysed adult mosquitoes is stimulated during or shortly before ecdysis. These observations suggest that vitellogenesis follows blood-ingestion, whereas JH activity may secondarily be promoted by vitellogenesis. It may be that vitellogenesis and JH activity are mediated by different brain hormones     

EFFECT OF A HIGH TEMPERATURE ON VITELLOGE-NESIS IN THE JAPANESE OAK SILKWORM,ANTHERAEA YAMAMAI (LEPIDOPTERA: SATURNIIDAE)*

Abstract The effect of a high temperature, i. e. 32°C. on vitellogenesis of the Japanese oak silkworm, Antheraea yamamai (Lepidoptera: Saturniidae) was markedly significant. Its extent was dependent on the development stage of the silkworm exposed to 32°C. When exposed to 32 °C since the 1st day after cocooning, titres of both vitellogenin (Vg) and soluble proteins in the fat body and hemolymph of mature larvae were evidently lower than those at 26°C. When pupae were maintained at 32°C since the 1st day after pupation. the titres of Vg in the fat body showed no significant difference from those at 26°C, but those in the hemolymph and the titres of vitellin (Vt) in the ovary mostly were obviously lower in contrast to those at 26°C. While exposed to 32°C since the 6th day after pupation, at most instance the tires of Vg both in the fat body and hemolymph were not markedly different from those at 26°C, and those of Vt in the ovary were significantly higher than those at 26°C, In addition, the changes in the titres of soluble proteins in the fat body and hemolymph as well as the ovary were monitored when pupae were maintained at 32°C since the 1st or 6th day after pupation. It is recommended that both mature larvae and pupae at cocooning stage and earlier pupal stage should not be exposed to 32°C when the silkworm is reared for egg raising.     

中国海产刚毛藻科(Cladophoraceae)八个新记录种

报道中国海产刚毛藻科(Cladophoraceae),沙生刚毛藻Cladophora arenaria,蝾螺刚毛藻C. conchopheria,暗色刚毛藻C. opaca,透明刚毛藻C. pellucida,微小刚毛藻C. pusilla,棉形刚毛藻C. rudolphiana,光毛刚毛藻C. sericea,美丽刚毛藻C. speciosa。     

山西轮藻属新植物

本文报道采自山西省的轮藻属植物2个新种,运城轮藻Chara yunchengensis,拟灰色轮藻C.pseudocanescens和3个中国新记录,阿尔泰轮藻C.altaica,豪威轮藻C.howeana,味美轮藻簇毛变种C.delicatula var.barbata