摘要
通过比较D系三倍体银鲫(Carassius auratus gibelio Bloch)与异源四倍体银鲫,我们发现异源四倍体的外周血与精巢组织跟三倍体银鲫存在明显差异。HE染色结果表明,异源四倍体银鲫外周血红细胞有明显的分裂倾向。利用流式细胞术对D系三倍体银鲫与异源四倍体银鲫外周血的DNA直方图进行比较,结果表明异源四倍体外周血的DNA直方图有两个主峰。此外,我们观察到异源四倍体银鲫精巢的三种类型,其中Ⅰ型精巢可以产生正常精子,Ⅱ型可观察到精小囊结构,但不能产生精子,Ⅲ型精巢未发育出精小囊结构。进一步用银鲫Vasa抗体对精巢切片进行组织免疫荧光共聚焦显微分析,结果表明,Ⅰ型精巢的生殖细胞完成了减数分裂,能观察到精原细胞、初级精母细胞、次级精母细胞,以及大量位于精小管中间的精子细胞和精子;而Ⅱ型精巢的生殖细胞不能完成第二次减数分裂,精小囊中存在大量的初级和次级精母细胞,没有精子细胞产生。研究丰富了对异源四倍体银鲫生物学性状的认识。
Gibel carp(Carassius auratus gibelio),a unique polyploid fish,is discovered to be able to reproduce by gynogenesis or sexuality reproduction.Since the allotetraploid gibel carp with 212 chromosomes were discovered from the gynogenetic offspring of gibel carp activated by red common carp sperm in 1990s,a lot of works have be done to study the genome organization and formation mechanism of them.The observations of genomic in situ hybridization and 45S rRNA gene localization on the allopolyploid metaphases showed the unusual allotetraploid gibel carp which contain the whole chromosomes of gibel carp and one chromosome set of common carp.However,the histological characterizations of allotetraploid gibel carp still remain unknown.In this study,we compared the histological features and found significant differences in peripheral blood cells and testis tissues between triploid(D clone) and allotetraploid gibel carp.The HE staining results showed that there were many abnormal red blood cells with small,round nuclear in the blood cell smear of allotetraploid gibel carp,which was obviously different from red blood cells with oval-shaped nuclear of triploid gibel carp.Moreover,the dual-nuclear red blood cells indicated a trend of cell division in peripheral blood of the allotetraploid gibel carp.Meanwhile,using the flow cytometry technique,we compared the DNA histogram of peripheral blood cells between triploid and allotetraploid gibel carp.The result revealed the existence of two kinds of cells with different DNA content in peripheral blood of allotetraploid gibel carp.In addition,we observed three testis types of allotetraploid gibel carp: TypeⅠ,wild type,which the sperm development was as normal as that of the male D clone gibel carp and large quantity of spermatids and sperms could be found in spermatogenic cysts;TypeⅡ,in which spermatids and sperms could not be observed in spermatogenic cysts;and Type Ⅲ,lacking the structure of spermatogenic cysts.Among those three types,TypeⅡ and type Ⅲ were the mainly forms of testis in allotetraploid gibel carp.To further study the characterizations of sperm development,fluorescent immunostaining was performed to compare different testis types of allotetraploid gibel carp by using the vasa antibody.The result revealed that germ cells in TypeⅠtestis could complete the meiosis process and produce a large number of spermatids and sperms in breeding season,while TypeⅡ testis was observed considerable quantities of primary and secondary speratocytes without spermatids in its spermatogenic cysts,indicating that germ cells cannot complete the second meiosis process in TypeⅡ testis.The unique characterization of red blood cell and testis could broaden our understanding about allotetraploid gibel carp.
出处
《水生生物学报》
CAS
CSCD
北大核心
2012年第2期229-235,共7页
Acta Hydrobiologica Sinica
基金
现代农业产业技术体系建设专项资金(NYCYTX-49)
中国科学院知识创新重要方向项目(KSCX3-EW-N-04)资助