一种雷氏放射孢子虫的鉴定及其特征描述

CHARACTERIZATION OF ONE TYPE OF RAABEIA ACTINOSPORE WITH SUBSIDIARY PROTRUSIONS ON THEIR CAUDAL PROCESSES IDENTIFIED IN GIBEL CARP POND

  • 摘要: 放射孢子虫(Actinosporean)是黏体动物在其中间宿主水生无脊椎动物体内的一个生活阶段。研究鉴定并描述了一种雷氏放射孢子虫的形态和分子特征。该放射孢子虫的主要形态结构是: 由三个极囊、内含孢原质的孢子体和三个尾突组成, 无孢柄。极囊位于孢子体顶端, 呈梨形, 长5.2 μm, 宽2.9 μm; 孢子体侧面观呈长椭圆形, 长16.4 μm, 宽9.5 μm; 三个尾突基本等长, 呈锚状, 平均长度102.6 μm, 宽9.54 μm, 尾突末端轻微的上翘。每个尾突远侧端表面有许多形状不规则的棘状小刺。18S rDNA序列比对表明, 该雷氏放射孢子虫与国外已报道的Myxobolus cultus 18S rDNA序列一致性最高, 达98.41%, 由此推测该雷氏放射孢子虫可能为M. cultus的对应放射孢子虫阶段。研究丰富了国内放射孢子虫的基础研究。

     

    Abstract: Actinosporea is a synonym of Myxosporea and is the infective stage for fish. This study identifies and characterizes one type of Raabeia actinospore in oligochaete specimen of Branchiura sowerbyi Beddard collected from a fish pond used for rearing gibel carp located in Caidian Experimental Station of the Institute of Hydrobiology. The spore is of characteristic “anchor” shape and without style, possesses a spore body with sporoplasm, 3 polar capsules and 3 caudal processes. Three pyriform polar capsules locate at apex of spore body with equal size (5.2 mm in length and 2.9 mm in width). Spore body shows oblong oval shape on lateral view average with 16.4 mm in length and 9.5 mm in width. Three caudal processes are approximately equal in length and width. Distally, each process possesses subsidiary protrusions which are irregularly distributed. Molecular analyses on 18S rDNA sequences indicate that this Raabeia actinospore type is most closely related to Myxobolus cultus with 98.14% identities, which indicated the type of Raabeia actinospore identified in this study is the counterpart actinosporean stage of Myxobolus cultus.

     

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