栉孔扇贝异精雌核发育四倍体早期胚胎发育的细胞学荧光显微观察  

Cytological observations on development of early embryos of allogynogenetic tetraploids of Chlamys farreri

作　　者：迟长凤[1] 杨爱国[1] 王清印[2] 刘志鸿[2] 周丽青[2] 

机构地区：[1]中国海洋大学生命科学与技术学部,山东青岛266003 [2]农业部海洋渔业资源可持续发展利用重点实验室中国水产科学研究院黄海水产研究所,山东青岛266071

出　　处：《中国水产科学》2007年第2期175-182,共8页Journal of Fishery Sciences of China

基　　金：国家自然科学基金资助项目(30600465);国家高技术研究发展计划"863"资助课题(2003AA603022);国家重大基础研究发展规划"973"资助课题(G1999012009);国家科技攻关计划项目(2004BA526B0103)

摘　　要：用1500μW/cm2的紫外线照射长牡蛎(Crassostrea gigas)精子60 s以进行灭活处理,并使之与栉孔扇贝(Chlamys farreri)卵子受精,在卵子受精后排出第一极体前用6-DMAP(50 mg/L)处理受精卵,持续处理35 min,抑制第一极体和第二极体的排放,诱导异精雌核发育四倍体。采用二脒基苯基吲哚(DAPI)荧光染色显微观察法,对灭活的长牡蛎精子诱导的栉孔扇贝雌核发育四倍体早期胚胎发育过程进行细胞学观察。结果表明:经紫外线灭活过的长牡蛎精子进入栉孔扇贝卵子后发生轻微膨胀;在第一次卵裂中期,精核形成一致密的染色质小体(DCB),位于两组分开的母本染色体之间,不参与核分裂;第一次卵裂结束时DCB滞留于两卵裂球的分裂沟上或进入其中一分裂球中;第二次卵裂过程中,DCB的去向与第一次卵裂时基本一致。6-DMAP处理有效地抑制了第一极体和第二极体的排出,从而使雌核四倍化。对担轮幼虫染色体倍性分析结果表明,通过本方法可以获得6.25%的四倍体幼虫。本研究还对灭活的异源长牡蛎精子诱导栉孔扇贝雌核发育四倍体过程中产生的复杂倍性、核物质分离紊乱及多精附卵现象进行了观察和分析。Zhikong scallop plays an important role in aquaculture in north of China because of their economic benefits. However, in recent years, cuhurable scallop sometime dies abnormally in different sea areas, and its yield and quality per unit reduce. Artificial polyploid provides a new way for us to improve the serious situa- tion. Triploid shellfish are of great interest in aquaculture because of their sterility, improved meat quality, and superior growth. But the triploid population is hard to be used in production abroad because they can＇ t reproduce and must be induced each year. Tetraploid breeding can solve the problem because that induced tetraploids provide an alternative method for mass production of triploids by mating them with normal diploids. The method is the best one for producing triploids in factory. Then study on the technique of tetraploid breeding is meaningful for triploid industrialization. The work results of our lab before showed that sperm of Crassostrea gigas could attach Chlamys farreri egg rapidly and penetrate into it after insemination, and sperm nucleus diffused and formed male pronucleus. Egg of Chlamys farreri resumed meiosis, released polar body and formed female pronucleus when it was activated by the heterogenous sperms. At last, male and female pronuclei fused and fertilized egg began the first cleavage. The chromosome could not be distributed equally into two cells in most of the zygote during the first cleavage, which resulted in that the hybrids between Zhikong scallop and Pacific oyster are not viable. In order to prevent any genetic paternal contamination,sperm of Crassostrea gigas must be genetically inactivated. This study aims to induce allogynogenesis tetraploid with 6-DMAP by inhibiting the release of the first and the second polar bodies, and observe cytological process of fertilization and the early embro development of allogynogenetic tetraploid, which can provide us some evidence for inducing allogynogenetic tetraploid and finding its mechanism. Allogynogenetic

关 键 词：栉孔扇贝 异精雌核发育 四倍体 细胞学 荧光显微观察 

分 类 号：Q959.215[生物学—动物学]