栉孔扇贝人工雌核发育的细胞学观察  

Cytological observations on artificially induced gynogenesis in Chlamys farreri

作　　者：潘英[1] 李琪[1] 于瑞海[1] 王如才[1] 

机构地区：[1]中国海洋大学教育部海水养殖重点实验室

出　　处：《水产学报》2004年第6期616-622,共7页Journal of Fisheries of China

基　　金：国家自然科学基金资助项目(30170735);教育部留学回国人员科研启动基金

摘　　要：运用荧光显微镜观察了栉孔扇贝正常卵子与雌核发育卵子在受精和成熟分裂过程中的核相变化。结果表明,尽管紫外线照射没有影响受精卵的成熟分裂以及雌性、雄性原核的形成,但使雌核卵的发育速度出现明显的滞缓。在第1次卵裂中期,雌核发育卵子中的雄性原核没有像雌性原核那样形成染色体,而是浓缩为一染色质小体(DCB),游离在细胞质中,不参与核分裂。胞质分裂结束时,DCB位于2个卵裂球之一的细胞质内或在赤道板处被分割成两部分。实验结果首次提供了栉孔扇贝雌核发育的细胞学证据。Nuclear changes in normal and gynogenetic eggs of the Chlamys farreri were examined under a fluorescence microscope during meiosis and fertilization. Two milliliters of sperm suspension ( 1×10~7 sperm·mL^(-1)) were spread on a 9.0 cm diameter plastic petri dish and placed on a reciprocal shaker 15 cm below a 15 W UV germicidal light. Haploid gynogenesis was induced by sperms, which were ultraviolet (UV)-irradiated for 30 s at an intensity of 2561 μW·cm^(-2)·s^(-1). Both the treated sperm and the untreated sperm (control) were mixed separately with a suspension of eggs ( 2×10~4 egg·mL^(-1)), and the eggs were then allowed to develop at 22℃. Samples of eggs from the two groups were taken at 5 min intervals up to 2 h after the addition of sperm and fixed in 2% formalin in seawater at 4℃. After rinsing three times with 0.1 mol·L^(-1) phosphate buffer containing 8% sucrose, the samples were stained with DAPI, and observed with a fluorescence microscope. The results obtained in this study demonstrated that although UV irradiation did not affect either meiotic maturation or the formation of the male and female pronuclei, their developmental progress was delayed apparently. At metophase of the first cleavage, the male pronucleus derived from sperm genome inactivated by UV-irradiated sperms inseminated with the normal egg formed no chromosomes, unlike the female pronucleus, but became a dense chromatin body (DCB), which did not participate in the karyokinesis at anaphase of the first cleavage as evidenced by chromosomal nondisjunction. On completion of cytokinesis of the first cleavage, the DCB was seen either in the cytoplasm of one of the two blastomeres or on the equatorial plate as two partitional parts. As did the normal eggs, the eggs inseminated with UV-irradiated sperm also developed in an asynchronous manner. On the other hand, in this study the eggs inseminated with UV-irradiated sperm developed slowly, and time difference between normal and gynogenetically developed eggs in reaching a developmental

关 键 词：栉孔扇贝 雌核发育 细胞学 4 6-二氨基-2-苯基吲哚 

分 类 号：S917[农业科学—水产科学]