摘要
采用透射电镜的方法研究曼氏无针乌贼(Sepiella maindroni)成熟精子的形态及结构特征。结果表明,曼氏无针乌贼的成熟精子由头部和尾部组成,尾部可明显地分为中段、主段和末段3部分。头部由顶体和细胞核构成,顶体呈倒"U"形,位于核的顶端,其内电子密度均匀。细胞核呈稍弯的长柱状纺锤形,为高电子密度的均质结构。尾部中段可见,是由无数个线粒体组成的线粒体距(mitochondrial spur)围绕尾部鞭毛。鞭毛由"9+2"结构的轴丝及外围9束粗纤维组成,形成"9+9+2"结构。尾部主段线粒体距消失,粗颗粒物质包绕轴丝。精子末段呈细长鞭状,由轴丝和质膜组成,随后包围轴丝的9束粗纤维直径变细直至消失,最终,轴丝仅为单一微管。研究认为,曼氏无针乌贼的精子类型是介于原生型与修饰型之间的中间型。
Sepiella maindroni belonging to Cephalopoda, Dibranchia, decapoda, Sepiidae, is an economic species of seafoods with nutrition and various medicinal properties. S. maindroni was one of the four major marine products in China in history, and widely spread along coastal areas, especially in the north of East China Sea along Zhejiang, and it is a traditional species of fishery with high economical value. However, Since late 1970s, due to over-fishing and eco-deterioration, the natural population of this species is nearly extincted So, to establish the aquaculture technology for this spceies is inevitable and necessary. The description of the sperm ultrastructure will provide information related to the fertilization mechanism and an understanding of the optimal culture method. In this study, the ultrastructure of the spermatozoon of S. maindroni was investigated using a transmission electron microscope. The results show that each spermatozoon consists of two parts, the head and the tail, and the tail can be divided into middle piece, principal piece and end piece. The head is composed of an inverted U-shaped acrosome and an elongated nucleus. The acrosome is filled with materials of a high electron density, positioned at the nucleus apex. Nucleus is slightly curved and long cylindrical spindle- shaped, and is highly condensed chromatin with high electron density. Mitochondria spur composed of numerous mitochondrias surrounds flagellum in the middle piece. The flagellum is composed of a ＂9＋2＂ axoneme surrounded by nine bundles of coarse fibres and forms the array of ＂9＋9＋2＂. in principal piece; mitochondria spur disappears and dense coarse granules surround axoneme. The end piece is thin and long, consisting of an axoneme and a plasma membrane. Subsequently the coarse fibres of the flagellum gradually decrease in diameter and eventually disappear, Distally, the flagellar axoneme degenerates into singlet microtubules. Maxwell （1983） suggested that molluscous spermatozoon was divided by two types, of which one was the primitive type of spermatozoon, and the other was the modified type of spermatozoon. The conclusion suggests that the spermatozoa of S. maindroni also differs from both the primitive and the modified types and is of an intermediate type.
出处
《中国水产科学》
CAS
CSCD
北大核心
2009年第1期8-14,共7页
Journal of Fishery Sciences of China
基金
国家高技术研究发展计划(863计划)资助项目(2006AA100301)
浙江省国际科技合作重大课题(2006C14017)
关键词
曼氏无针乌贼
精子
超微结构
Sepiella maindroni
spermatozoon
ultrastructure
intermediate type
