Naldoni Juliana, Zatti Suellen A, Capodifoglio Kassia R H, Milanin Tiago, Maia Antonio A M, Silva Marcia R M, Adriano Edson A
Animal Biology Department, Institute of Biology, University of Campinas, Sao Paulo, Brazil;
Veterinary Medicine Department, College of Animal Science and Food Engineering, Sao Paulo University, Sao Paulo, Brazil;
Folia Parasitol (Praha). 2015 Jan 1;62:2015.014. doi: 10.14411/fp.2015.014.
Myxobolus filamentum sp. n. was found infecting gill filaments of three of 39 Brycon orthotaenia Günther specimens examined (8%), which were taken from the river São Francisco in Minas Gerais state, Brazil. Plasmodia of the parasite were white and long, measuring 5 mm in lenght. Mature spores of M. filamentum sp. n. were oval from the frontal view and biconvex from the lateral view, measuring 7.5-9.7 µm (9.0 ± 0.3 µm) in length and 5.2-7.3 µm (6.2 ± 0.4 µm) in width. The polar capsules were elongated and equal in size, measuring 3.8-5.5 µm (4.7 ± 0.3 µm) in length and 1.3-2.2 µm (1.7 ± 0.1 µm) in width. The development of the parasite led to compression of the adjacent tissues and inflammatory infiltrate with granulocytic cells. Ultrastructural observation revealed that the plasmodia were delimited by two membranes, which had numerous and extensive pinocytotic channels extending into the wide ectoplasm zone. The plasmodial wall exhibited abundant villi-like projections and a thin layer of granular material prevented direct contact between the plasmodial wall and the host tissue. Phylogenetic analysis, based on 18S rDNA, showed M. filamentum sp. n. as a sister species of Myxobolus oliveirai Milanin, Eiras, Arana, Maia, Alves, Silva, Carriero, Ceccarelli et Adriano, 2010, a parasite of other fish species of the genus Brycon Müller et Troschel from South America.
丝状粘体虫新种（Myxobolus filamentum sp. n.）在检查的39尾巴西小口脂鲤（Brycon orthotaenia Günther）标本中的3尾（8%）的鳃丝中被发现，这些标本采自巴西米纳斯吉拉斯州的圣弗朗西斯科河。该寄生虫的孢囊呈白色且长，长度为5毫米。丝状粘体虫新种的成熟孢子从正面看呈椭圆形，从侧面看呈双凸形，长7.5 - 9.7微米（9.0 ± 0.3微米），宽5.2 - 7.3微米（6.2 ± 0.4微米）。极囊细长且大小相等，长3.8 - 5.5微米（4.7 ± 0.3微米），宽1.3 - 2.2微米（1.7 ± 0.1微米）。该寄生虫的发育导致相邻组织受压，并伴有粒细胞的炎性浸润。超微结构观察显示，孢囊由两层膜界定，这两层膜有许多广泛的胞饮通道延伸到宽阔的外质区。孢囊壁表现出丰富的绒毛状突起，一层薄的颗粒物质阻止了孢囊壁与宿主组织的直接接触。基于18S rDNA的系统发育分析表明，丝状粘体虫新种是奥利维拉粘体虫（Myxobolus oliveirai Milanin, Eiras, Arana, Maia, Alves, Silva, Carriero, Ceccarelli et Adriano, 2010）的姐妹种，后者是来自南美洲小口脂鲤属（Brycon Müller et Troschel）其他鱼类的寄生虫。
