摘要
研究测定了寄生于草鱼肠道的鲩肠袋虫的18S rDNA序列。鲩肠袋虫的18S rDNA基因序列包括1638个碱基。分别用3种分析方法(邻接法、最大简约法、贝叶斯法)构建了毛口亚纲的系统发育树,得到结果如下:均支持毛口亚纲为单系发生且内分前庭目、内毛目和澳大利亚枝3个类群(100%Bay、100%MP、100%NJ);均支持内毛目(100%Bay、98%MP、93%NJ)、澳大利亚枝(100%Bay、97%MP、99%NJ)的单系性和前庭目的并系性。3种构树方法都支持鲩肠袋虫与澳大利亚枝聚类(100%Bay、100%MP、100%NJ),而后与"内毛目+前庭目(部分)"构成姊妹群(100%Bay、85%MP、72%NJ);而结肠小袋纤毛虫与"澳大利亚枝+鲩肠袋虫"以及"内毛目+前庭目(部分)"分枝并列,共同构成毛口亚纲(100%Bay、100%MP、100%NJ)。这暗示了肠袋虫类群在系统发育上的并系性和其分类阶元的提升。
Balantidium ctenopharyngodoni,an obligatory intestinal symbiont and possibly opportunistic parasite of grass carp（Ctenopharyngodon idella）,was first discovered and named by Chen（1955）.It mainly inhabits the cream-like luminal contents and spaces between mucosal folds of the hindgut.In the present study,twenty two or three-summer grass carp were bought from Wuhan Fruit-Lake Market in March 2009 and transported alive to the laboratory for further examination.All fish samples were dissected and the intestines were cut to collect the luminal contents into Petri dishes for examination.Then 0.65% saline solution was added to the contents and waited for a few minutes to allow B.cteno-pharyngodoni swim free of luminal contents.The ciliates were collected with Pasteur micropipette and washed twice in distilled water.The parasite gDNA was isolated by proteinase K digestion overnight at 37℃,followed by phe-nol-chloroform protein extraction and ethanol precipitation.Its 18S rDNA was then sequenced,which contains 1638 base pairs.Phylogenetic trees were also constructed by the neighbour joining method,the maximum parsimony method and the Bayesian method,respectively.The results indicated that the subclass Trichostomatia was monophyletic and composed of the order Entodiniomorphida,Vestibuliferida and Australian clade（100% Bay;100% MP;100% NJ）.The oder Entodiniomorphida（100% Bay;98% MP;93% NJ） and Australian clade（100% Bay;97% MP;99% NJ） showed their monophyletic while the order Vestibuliferida showed its paraphyly.As to the phylogenetic position,B.cteno-pharyngodoni first clustered with the Australian clade with higher bootstrap values（100% Bay;100% MP;100% NJ）.Then they formed a sister clade to ＂Entodiniomorphida＋ Vestibuliferida＂（100% Bay;85% MP;72% NJ）.B.coli,as an isolated taxon,was joined together with ＂Australian clade ＋ B.ctenopharyngodoni＂ and ＂Entodiniomorphida ＋ Vestibu-liferida（part）＂ to form the subclass Trichostomatia（100% Bay;100% MP;100% NJ）.It also suggested that the genus Balantidium should be recognized as a higher taxon.
出处
《水生生物学报》
CAS
CSCD
北大核心
2011年第2期203-209,共7页
Acta Hydrobiologica Sinica
基金
国家自然科学基金(30870275)、(31000947)
农业部海水养殖生态与质量控制重点实验室开放课题(2008C1201)
农业部淡水鱼类遗传育种和养殖生物学重点实验室开放课题(BZ2009-02)
淡水生态与生物技术国家重点实验室开放课题(2009FB08)
淮安市科技支撑计划(SN1087)
湖北省教育厅优秀中青年人才项目(Q20101702)资助
