摘要
研究基于形态和分子信息重描述了寄生于嘉陵江重庆段鲫(Carassius auratus Linnaeus)鳃部和胆囊的尖形碘泡虫(Myxobolus acutus Wu and Chen,1987),并获得了该虫体的18S rDNA和ITS1 rDNA序列。尖形碘泡虫成熟孢子壳面观呈梨形,前端稍尖,后端钝圆,缝面观呈宽纺锤形。孢子长(13.6±0.9)μm[(11.4—15.3)μm],宽(10.2±0.9)μm[(7.5—12.8)μm],厚(7.6±0.6)μm[(6.9—8.3)μm]。两梨形极囊开口处紧靠并位于孢子前端,极囊大小不等,大极囊长(6.2±0.4)μm[(5.1—7.5)μm],宽(3.8±0.4)μm[(2.8—4.7)μm],极丝盘绕5—8圈,小极囊长(2.7±0.4)μm[(1.7—3.7)μm],宽(1.4±0.2)μm[(0.9—1.9)μm],极丝盘绕2—3圈。基于18S rDNA为分子标记的系统发育分析显示:尖形碘泡虫与中华单极虫(Thelohanellus sinensis)有最近的亲缘关系,两物种形成的进化支与贝壳碘泡虫(M.musseliusae)、苍梧碘泡虫(M.tsangwuensis)和鳃基碘泡虫(M.basilamellaris)形成的进化支呈姐妹群关系。通过系统发育与寄生部位关系的分析结果推测,尖形碘泡虫的初始寄生部位可能为鳃,而胆囊则是该物种后来适应的新的寄生部位。
Myxosporeans are obiligate endoparasites belonging to the phylum Cnidaria that includes mainly free-living species,such as sea anemones,hydras or jellyfish.Myxosporeans infecting wild and farmed fishes represent an important pathogenic group with a worldwide distribution.Myxosporidiosis can cause severe ecological and economic effects,which draw extensive attention to many people.Although myxosporeans were discovered almost 200 years ago,their classification was debated for a long time,especially about their higher taxonomic placement.Until recently,many discoveries sealed the demise of Myxozoa as a phylum and supported its inclusion in Cnidaria.Up to now,there are some 2600 described myxosporeans species with only about 23%of them have molecular sequence data.Therefore,there are still a lot of molecular information of known species to be supplemented and perfected.The traditional classification and identification of these species were based on their spore morphology.However,many taxonomists are aware of the limitations of the morphology-only classification because of the simplified body structure and the plasticity of some myxospores.Nowadays,almost all studies about taxonomy of myxosporeans are conducted using a combination of morphological and molecular data.Myxobolus acutus Wu and Chen,1987 was first reported from gills and kidneys of Carassius auratus Linnaeus collected from Hubei,China,in the year 1983—1984.Wu and Chen named the species and gave a full description of the morphology of the parasite but without molecular data.This study redescribed the species infected the gills and gallbladders of C.auratus from Jialing River of Chongqing using the 18S rDNA and ITS1 rDNA sequences and its morphological and molecular data.The mature myxospores of M.acutus were pyriform with slightly narrow anterior and blunt posterior in valvular view.They were wide spindle-shaped in sutural view.The spores were(13.6±0.9)μm[(11.4—15.3)μm]in length,(10.2±0.9)μm[(7.5—12.8)μm]in width and(7.6±0.6)μm[(6.9—8.3)μm]
作者
石小威
王茂
陈鸿真
高磊
刘晓聪
杨承忠
赵元莙
SHI Xiao-Wei;WANG Mao;CHEN Hong-Zhen;GAO Lei;LIU Xiao-Cong;YANG Cheng-Zhong;ZHAO Yuan-Jun(Chongqing Key Laboratory of Animal Biology,College of Life Sciences,Chongqing Normal Universtiy,Chongqing 401331,China)
出处
《水生生物学报》
CAS
CSCD
北大核心
2022年第4期555-562,共8页
Acta Hydrobiologica Sinica
基金
国家自然科学基金(31970409)
重庆市留学人员回国创业创新支持计划(cx2018108)
重庆市教委科学技术研究项目(KJQN201900505)资助。
关键词
重描述
18S
rDNA
ITS1
rDNA
分子系统学
形态特征
寄生部位
鲫
尖形碘泡虫
Redescription
18S rDNA
ITS1 rDNA
Molecular phylogenetic
Morphological characteristics
Parasitic site
Carassius auratus
Myxobolus acutus
