秉志锥虫的重描述及其系统发育分析

Redescription and phylogenetic study of Trypanosoma pingi

为丰富鱼类锥虫的物种资源,了解养殖鱼类锥虫的感染情况,通过调查湖北地区鱼类锥虫的感染情况,在武汉市江夏区牛山湖渔场养殖的鲫血液中分离到一种锥虫,并采用形态学和分子生物学数据对该锥虫进行描述。通过形态特征和衍征的比较与分析,发现该锥虫与秉志锥虫(Trypanosoma pingi)形态一致,故鉴定为秉志锥虫。扩增并获得秉志锥虫的18SrDNA分子序列,通过序列比对分析,发现其与黄颡锥虫(Trypanosoma pseudobagri)18SrDNA序列相似性最高,为94.62%,分子系统发育树分析显示秉志锥虫落于淡水鱼类锥虫支类,与黄颡锥虫(Trypanosoma pseudobagri)形成姊妹群。

Fish trypanosome is a kind of flagellated parasitic protozoa which parasitizes in the blood of fish,causing harm of fish and economic losses.Clinical signs of the disease include depressed,general oedema and visceral hemorrhage.But the taxonomic of trypanosome and basic research is quite limited and backward.During the parasite fauna investigation,a freshwater fish trypanosome was isolated from the blood of crucian carps.According to the morphological comparison between the trypanosome we got and other trypanosomes data,it was identified as Trypanosoma pingi and was redescribed using 13 morphometric characterizations.SSU rDNA sequences were also compared.The sequence alignments revealed that the present SSU rDNA sequence was most similar to that of Trypanosomapseudobagri（94.62%）,but the morphological variation were significant different,suggesting that T.pingi and T.pseudobagri might be different genotypes.