摘要
海城碘泡虫原始描述中形态数据较为简单,且存在多个宿主及寄生部位,其有效性有待确定。利用现行主流的黏孢子虫形态特征和基因标记系统分析相结合的分类学方法,对采自太湖棒花鱼鳃丝的海城碘泡虫进行了补充描述。该碘泡虫孢囊呈白色,圆形,大小为(0.6—1.1)mm。成熟孢子正面观近似椭圆形,上端稍尖,侧面观呈纺锤型,孢子长(10.8±0.7)μm(10.1—11.5μm),孢子宽:(8.1±0.5)μm(7.5—9.0μm),孢子厚:(5.7±0.4)μm(5.2—9.0μm);两极囊呈梨形,大小存在细微差别,极囊顶端存在突起,大极囊长:(4.7±0.5)μm(4.8—6.7μm),宽:(2.5±0.2)μm(3.2—4.3μm),小极囊长:(4.4±0.2)μm(4.1—4.8μm),宽:(2.2±0.1)μm(2.0—2.5μm);极丝盘绕4—5圈。基于18S r DNA序列(Gen Bank登录号:KY965936)比对分析,该碘泡虫与放射孢子虫Hexactinomyxon type 2相似率最高,为97%。系统发育分析表明,该碘泡虫与Hexac-caudatus和Myxobolus squamae聚为独立分支,和其他已报道的黏孢子虫亲缘关系较远。研究在补充了海城碘泡虫形态学、基因标记序列信息基础上,推断了该虫生活史。
Myxobolus haichengensis Chen,1958 forms numerous small plasmodia on the gill filaments of wild cyprinid Abbottina rivularis Basilewaky.The species described originally was lacking important characters,which made the accurate identification difficult.Here,we supplemented its characteristics with morphological and molecular data.Plasmodia of M.haichengensis are oval.Mature spores are ellipsoidal-shaped in frontal view and fusiform-shaped in lateral view,measuring(10.8±0.7)μm(10.1—11.5μm)long,(8.1±0.5)μm(7.5—9.0μm)wide,and(5.7±0.4)μm(5.2—9.0μm)thick;two unequal polar capsule are pyriform with tapering anterior,large polar capsule averaging(4.7±0.5)μm(4.8—6.7μm)long and(2.5±0.2)μm(3.2—4.3μm)wide;small polar capsule averaging(4.4±0.2)μm(4.1—4.8μm)long and(2.2±0.1)μm(2.0—2.5μm)wide;polar filaments coil with four to five turns.The nuclear 18S r DNA sequence was obtained and deposited in Gen Bank(KY965936),and sequences alignment analyses revealed that M.haichengensis was most similar with the actinosporean Hexactinomyxon type 2(AY162272,97%)released from the freshwater tublificid oligochaete Limnodrilus hoffmeisteri.
引文
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