寄生于金鱼肌肉和肝胰脏的吴李碘泡虫形态特征与分子鉴定

doi:10.14012/j.cnki.fjsc.2024.01.009

摘要/Abstract

摘要：

2021年9月,北京市通州区相邻两家观赏鱼养殖场的金鱼(Carassius auratus)发生孢子虫病,患病鱼头背部肌肉隆起或腹部膨大而失去观赏价值,并造成少量死亡。为鉴定金鱼源孢子虫的种类,采集具有临床症状的病鱼,取病灶组织制作水封片进行孢子虫形态观察和形状测量,并进一步对孢子虫的18S rDNA进行克隆、测序和生物信息学分析。结果表明:造成金鱼头背部肌肉隆起或肝胰脏膨大的孢子虫壳面观均呈梨形,前端有2个八字形排列的极囊,极囊约占孢子虫全长的一半,极丝圈数为7~9圈,形态特征和形状测量数据与吴李碘泡虫(Myxobolus wulii)相似。孢子虫的18S rDNA序列经Blast同源性检索,与吴李碘泡虫同源性最高,相似性在99%以上,构建的系统发育树也与吴李碘泡虫聚为一枝。因此,确认这两起金鱼孢子虫病的病原为吴李碘泡虫,这是该碘泡虫寄生于金鱼肌肉的首次报道,为其在金鱼寄生部位的研究提供了资料。

关键词: 金鱼, 吴李碘泡虫, 形态特征, 分子鉴定

Abstract:

In September 2021,the goldfish (C.auratus) cultured at two adjacent ornamental fish farms in Tongzhou District of Beijing suffered from sporidiosis,and displayed dorsolateral humps or swollen abdomen,which lost their ornamental value and caused a small number of deaths.In order to identify the specie of parasite and enrich its epidemiological data,the lesion tissues from dorsolateral humps and hepatopancreas of diseased fish were collected.Morphological observation and spores measurement were carried out.18S rDNA gene of the parasites was then cloned,sequenced and analyzed.The results showed that the morphological characteristics of the spore was pyriform in shape,and two polar capsules arranged in an octagonal shape at the front which accounts for about half of the entire length of the spore.The measured data of the spores were 17.58 μm and 18.09 μm in average length,11.02 μm and 11.82 μm in average width,and there were 7-9 loops of polar filaments,which were similar to those of M.wulii. The partial sequences of 18S rDNA gene of the parasites had the highest homology with M.wulii based on blast from GenBank,and the similarity was more than 99%.In addition,in the constructed phylogenetic tree by 18S DNA gene,the isolated spore was also clustered with the M.wulii.Therefore,it was confirmed that the parasites caused goldfish sporidiosis in these two cases were both M.wulii,and this was the first report that M.wulii parasitized in goldfish muscle.

Key words: Carassius auratus, Myxobolus wulii, morphological characteristic, molecular identification

中图分类号:

S943

王小亮, 曹欢, 王姝, 吕晓楠, 王静波, 张文, 王澎, 徐立蒲. 寄生于金鱼肌肉和肝胰脏的吴李碘泡虫形态特征与分子鉴定[J]. 渔业研究, 2024, 46(1): 85-91.

WANG Xiaoliang, CAO Huan, WANG Shu, LÜ Xiaonan, WANG Jingbo, ZHANG Wen, WANG Peng, XU Lipu. Morphological characteristic and molecular identification of Myxobolus wulii found in dorsolateral muscle and hepatopancreas of diseased goldfish(Carassius auratus)[J]. Journal of Fisheries Research, 2024, 46(1): 85-91.

图/表 7

图1 感染孢子虫的金鱼背部隆起（A）、肝胰脏膨大（B）

Fig.1 Showing dorsolateral humps (A) and enlarged hepatopancreas (B) of goldfish infected by Myxobolus spp.

图2 BTXD210907肌肉隆起组织流出液水浸片（400×）

Fig.2 The dorsolateral humps tissue outflow of BTXD210907 smear showing cyst and numerous spores (400×)

图3 BTXL210907 金鱼肝胰脏组织水浸片（400×）

Fig.3 The hepatopancreas tissue of goldfish BTXL210907 smear showing cyst and numerous spores (400×)

图4 孢子虫的形态注:A为光学显微镜下孢子虫的形态(1 000×);B为单孢子经数码放大的形态。

Fig.4 The morphology of Myxobolus spp. Notes:A.Spore morphology under a light microscope(1 000×);B.A spore magnified by a digital zoom.

表1 感染金鱼组织的孢子虫形态特征

Tab.1 Morphological characteristics of Myxobolus spp. isolated from diseased goldfish

采集地 Location	宿主 Host	寄生部位 Site of infection	孢子长 SL	孢子宽 SW	孢子虫厚度 ST	极囊长 PCL	极囊宽 PCW	极丝圈数 PFC
北京 Beijing	金鱼 C.auratus auratus	肌肉	17.58±0.85	11.02±0.58	8.68±0.42	8.82±0.48^a 8.35±0.48^b	3.88±0.27^a 3.83±0.25^b	7~9
北京 Beijing	金鱼 C.auratus auratus	肝胰脏	18.09±0.54	11.82±0.44	8.82±0.52	8.25±0.16^a 7.95±0.31^b	3.92±0.26^a 3.53±0.26^b	7~9

图5 基于18S rDNA 部分序列构建的系统发育树(NJ 树)

Fig.5 Phylogenetic tree（NJ tree） based on the 18S rDNA partial sequence of the parasites

表2 吴李碘泡虫不同株的形态学特征

Tab.2 Morphological character of different strains of M.wulii

采集地 Locations	宿主 Hosts	寄生部位 Sites of infection	孢子长 SL	孢子宽 SW	极囊长 PCL	极囊宽 PCW	极丝圈数 PFC	文献来源 Reference
日本 Japan	金鱼 C.auratus auratus	肝胰脏	17.1	10.5	8.0	3.4	7~9	Zhang J Y等^[9]
中国湖北 Hubei,China	异育银鲫 C.auratus gibelio	肝胰脏	17.7	10.6	9.3^a 9.0^b	3.7^a 3.6^b	7~9	Zhang J Y等^[9]
中国重庆 Chongqing,China	鲫 C.auratus auratus	鳃	14.45	9.87	7.67	3.90	7~9	杨承忠等^[11]

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