miRNA在哺乳动物配子发生中的作用研究进展

哺乳动物配子发生的基因表达调控包括编码基因的阶段特异性表达调控及非编码基因的转录和转录后水平调控。微小RNA(microRNA, miRNA)作为一类小的非编码RNA, 通过识别靶基因非翻译区的结合位点, 导致mRNA降解或者蛋白质翻译抑制, 从而在转录后水平发挥调控作用。近年来, miRNA在哺乳动物生殖活动中的作用逐渐被揭示, 越来越多的研究表明, miRNA在哺乳动物精子发生、精子成熟、卵母细胞成熟、卵泡发育及早期胚胎发育等过程中都发挥着重要的调节作用, 其可通过调节支持细胞的增殖和凋亡或精原细胞、精母细胞及精细胞的细胞周期进程, 在精子发生的不同阶段发挥间接或直接调控作用, 也可通过调节卵母细胞、卵丘细胞以及颗粒细胞的增殖、凋亡、激素合成和细胞间作用, 对卵母细胞的发育和成熟过程进行调控。作者主要介绍了在哺乳动物配子发生过程中, miRNA的细胞和阶段特异性表达及其对靶基因的调节作用, 以期为深入研究哺乳动物配子发生的调控机制提供参考。     

斑腿蝗科2种蝗虫卵子发生比较研究

对短星翅蝗(Calliptamus abbreviatus)和长翅素木蝗(Shirakiacris shirakii)组织学观察与测量的结果表明:卵母细胞体积和形态变化显著,呈现先慢后快的发育特点;细胞核体积增长在发育初期增长速度大于后期;滤泡细胞体积在卵黄发生期达到峰值,呈高柱状,卵黄发生结束后退化,呈柳叶状;2种蝗虫卵子发生的发育进程具明显的种间差异。     

龟纹瓢虫生殖系统及卵子发生观察

【目的】龟纹瓢虫捕食蚜虫、粉虱、木虱等多种害虫,是农林业重要天敌昆虫。掌握龟纹瓢虫雌雄内生殖系统结构及卵细胞生成过程,为龟纹瓢虫人工繁育提供理论依据。【方法】采用组织石蜡切片技术和内部解剖,在光学显微镜下观察龟纹瓢虫雌雄成虫内生殖器及卵子发生过程。【结果】龟纹瓢虫雄性内生殖系统包括1对精巢、1对雄性附腺、1对输精管、贮精囊、射精管;雌性内生殖系统包括1对卵巢、1对侧输卵管、中输卵管、受精囊、生殖腔,每侧卵巢含11~13根卵巢管;卵巢管生长区可见4粒发育程度不同的卵母细胞,根据卵黄沉淀情况、滤泡细胞形态变化将卵子发生划分为前期、中期、后期、末期4个时期。【结论】卵巢结构、卵巢管和卵母细胞数量有助于解释龟纹瓢虫产卵量,不适宜的饲养条件可能抑制卵巢发育,进而导致龟纹瓢虫产卵量发生变化。因此,为实现龟纹瓢虫的规模化应用,人工繁育中应创造最优营养和环境条件以保障产生更多成熟卵细胞。     

凡纳滨对虾卵子发生的超微结构

利用透射电镜研究凡纳滨对虾卵子发生过程中细胞内部结构的变化。结果显示，卵原细胞结构简单，代谢水平低，核孔稀少，通过核周池来完成核、质之间的物质交换。卵黄发生前晚期和卵黄发生初期的卵母细胞变化显著：核膜凹凸不平，核仁数量多，核孔密集，大量核仁外排物经核孔输送到卵质中；卵质中胞器极为丰富和发达，代谢活性极强。卵黄发生旺盛期是卵黄大量形成的阶段，卵质边缘还呈辐射状排列了一圈椭圆形皮质棒，细胞出现微吞饮活动并形成卵黄膜。卵黄发生晚期卵质中充满了粗大的卵黄粒和脂滴，胞器锐减。另外，探讨了卵细胞内部结构的变化和卯黄形成的关系以及皮质棒的来源与功能。     

锯缘青蟹卵巢发育的组织学观察

根据锯缘青蟹卵巢的外部形态和内部组织学特征,卵巢发育可以划分为六个时期:未发育期、发育早期、发育期、将成熟期、成熟期和排卵后期。在发育早期,多数卵母细胞胞质中有多个嗜酸性液泡,这种结构在其他十足类卵母细胞中较少见。少数个体在发育早期发生卵母细胞全面退化,这种现象可能是缺乏交配或饥饿造成的。     

温度对野蚕黑卵蜂卵巢发育和卵子发生的影响

分别在19、22、25、28和31℃条件下,观察不同温度对野蚕黑卵蜂Telenomus theophilae Wu et Chen(Hymenoptera：Scelionidae)雌蜂卵巢发育和卵子发生的影响。结果表明,在19～28℃之间,雌蜂卵巢生长,基端卵子生长和卵巢中卵子发生的速度随温度上升而逐步加快。在31℃下,羽化1d后雌蜂卵巢长宽显著短于25℃和28℃下同日龄的的雌蜂,卵巢中成熟卵也显著减少,但从羽化后第2d开始,各项指标均与25℃和28℃下的接近。这说明该蜂对温度的适应范围较广,在19～31℃之间,虽然野蚕黑卵蜂的卵巢发育速度不同,但所能达到的最大卵量没有明显差异,说明这5个温度对于该蜂的卵子形成均较为适宜。     

异色瓢虫卵巢发育及卵子发生过程观察

为明确异色瓢虫卵巢发育和卵子发生过程,采用内部解剖和石蜡切片技术,分别对异色瓢虫卵巢形态和卵母细胞组织结构进行系统观察,并对其发育阶段进行了划分。结果表明:异色瓢虫雌性内生殖器官主要由1对卵巢、1对侧输卵管、1根中输卵管、受精囊、受精囊附腺、交配囊和黏腺组成;根据有无卵室和卵黄沉积情况将其卵巢发育划分为未分化期、生长发育初期、卵黄沉积期和成熟待产期4个等级;根据卵母细胞所在位置、体积和细胞核的变化,滋养细胞和滤泡细胞的形态变化以及卵黄沉积情况,将异色瓢虫卵子发生划分为卵母细胞分化期、卵母细胞营养期和卵黄形成期3个时期7个阶段。本研究首次对异色瓢虫的卵子发生进行了观察,并初步划分了异色瓢虫卵巢发育的分级标准。     

Modification of essential fatty acid composition in broodstock of cultured European eel Anguilla anguilla L

Farmed eels had lower levels of arachidonic acid (20:4 n‐6) (ARA) and higher ratios of eicosapentaenoic acid (20:5 n‐3) (EPA):ARA compared to wild European eels collected from the Baltic Sea and southern Norwegian coast. Eels fed a formulated feed (JD) with a distribution of essential fatty acids (EFA) resembling wild European eel were sampled after 0, 5, 10, 14 and 44 weeks of feeding to examine changes in fatty acid composition (FAC) in ovaries, visceral fat and muscle. The results showed a slow but steady incorporation of EFA. Lipids are incorporated in the oocytes early in oogenesis, and the leading cohort of oocytes is rich in lipid droplets before the onset of vitellogenesis. This indicates that feeding with optimized broodstock feeds should start early to allow the incorporation of EFA in the first cohort of oocytes. At least 14 weeks of feeding is required to change lipid EFA in broodstock eel to resemble EFA in the diet or in wild fish. After 44 weeks of feeding, ARA was significantly higher in the neutral lipids of ovaries (1.9%) compared to visceral fat (1.2%) or muscle (1.0%). EPA:ARA ratios decreased two‐ to threefold in all tissues examined during that time. ARA and docosahexaenoic acid (22:6 n‐3) (DHA) had accumulated in ovarian polar lipids.     

Research Progress on Oviposition-Related Genes in Insects

Oviposition-related genes have remained a consistent focus of insect molecular biology. Previous research has gradually clarified our mechanistic understanding of oviposition-related genes, including those related to oviposition-gland-related genes, oogenesis-related genes, oviposition-site-selection-related genes, and genes related to ovulation and hatching. Moreover, some of this research has revealed how the expression of single oviposition-related genes affects the expression of related genes, and more importantly, how individual node genes function to link the expression of upstream and downstream genes. However, the research to date is not sufficient to completely explain the overall interactions among the genes of the insect oviposition system. Through a literature review of a large number of studies, this review provides references for future research on oviposition-related genes in insects and the use of RNAi or CRISPR/Cas9 technology to verify the functions of oviposition-related genes and to prevent and control harmful insects.