Adriano E A, Arana S, Alves A L, Silva M R M, Ceccarelli P S, Henrique-Silva F, Maia A A M
Departamento de Ciências Biológicas, Universidade Federal de São Paulo, Diadema, SP, Brazil.
Vet Parasitol. 2009 Jun 10;162(3-4):221-9. doi: 10.1016/j.vetpar.2009.03.030. Epub 2009 Mar 27.
This work is part of an ongoing investigation into the characteristics of Myxozoan parasites of freshwater fish in Brazil and was carried out using morphology, histopathology and molecular analysis. A new Myxosporea species (Myxobolus cordeiroi) is described infecting the jaú catfish (Zungaro jahu). Fifty jaú specimens were examined and 78% exhibited plasmodia of the parasite. The plasmodia were white and round, measuring 0.3-2.0mm in diameter and the development occurred in the gill arch, skin, serosa of the body cavity, urinary bladder and eye. The spores had an oval body and the spore wall was smooth. Partial sequencing of the 18S rDNA gene resulted in a total of 505bp and the alignment of the sequences obtained from samples in different organs revealed 100% identity. In the phylogenetic analysis, the Myxobolus species clustered into two clades-one primarily parasites of freshwater fish and the other primarily parasites of marine fish. M. cordeiroi n. sp. was clustered in a basal position in the freshwater fish species clade. The histological analysis revealed the parasite in the connective tissue of the different infected sites, thereby exhibiting affinity to this tissue. The plasmodium was surrounded by an outer collagen capsule of fibers with distinct orientation from the adjacent connective tissue and an inner layer composed of delicate collagen fibrils-more precisely reticular fibers. The development of the parasite in the cornea and urinary bladder caused considerable stretching of the epithelium.
这项工作是对巴西淡水鱼粘孢子虫寄生虫特征进行的一项正在进行的调查的一部分，采用了形态学、组织病理学和分子分析方法。描述了一种感染雅乌鲶鱼（Zungaro jahu）的新粘孢子虫物种（Myxobolus cordeiroi）。检查了50个雅乌鲶鱼标本，78%的标本显示有该寄生虫的包囊。包囊呈白色圆形，直径为0.3 - 2.0毫米，在鳃弓、皮肤、体腔浆膜、膀胱和眼睛中发育。孢子呈椭圆形，孢子壁光滑。18S rDNA基因的部分测序共得到505个碱基对，对不同器官样本获得的序列进行比对显示100%的同一性。在系统发育分析中，粘孢子虫物种聚为两个分支——一个主要是淡水鱼寄生虫，另一个主要是海水鱼寄生虫。新种科代罗粘体虫（M. cordeiroi n. sp.）聚集在淡水鱼物种分支的基部位置。组织学分析显示寄生虫存在于不同感染部位的结缔组织中，从而表现出对该组织的亲和力。包囊被一层外部胶原纤维囊包围，其纤维方向与相邻结缔组织明显不同，内部由精细的胶原纤维组成——更确切地说是网状纤维。寄生虫在角膜和膀胱中的发育导致上皮组织显著伸展。
