National Institute of Water and Atmospheric Research Ltd, Private Bag 14-901, Kilbirnie, Wellington 6241, New Zealand.
Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de Murcia, Murcia, Spain.
Parasitology. 2011 Jun;138(7):836-47. doi: 10.1017/S0031182011000527. Epub 2011 Apr 18.
Scuticociliates are histophagous marine parasites that cause mortality in fish. Acid phosphatases (AcPs) are considered virulence factors and they are used by different parasites to dephosphorylate host molecules. The aim of this work was to characterize the AcPs from 3 scuticociliate species, Uronema marinum, Miamiensis avidus and Parauronema virginianum, which parasitize marine finfish species. We identified AcP activity (pH 5.2) with differential cellular distribution in the 3 parasite species. Native gel electrophoresis of ciliate lysates revealed the presence of 1 high molecular weight AcP activity band in M. avidus (tartrate-sensitive), several low molecular weight AcPs in U. marinum and 1 low molecular weight band only in P. virginianum (tartrate-resistant). Scuticociliate AcP was inhibited by specific inhibitors of tyrosine protein phosphatases. AcP decreased upon starvation but rapid reactivation occurred following exposure to skin mucus. Groper (Polyprion oxygeneios) peripheral blood leucocytes (PBLs) and, to a lesser extent, red blood cells, also increased AcP activity. Protein tyrosine phosphatase PTP1b was primarily detected in the plasma membrane of M. avidus and ingestion of groper PBLs upregulated its expression. M. avidus recovered from experimentally infected groper had greater levels of PTP1b expression than the injected suspension. The present results highlight the importance of PTPs in histophagous parasites and their interaction with fish host's factors.
旋口虫是一种食源性海洋寄生虫，可导致鱼类死亡。酸性磷酸酶（AcP）被认为是毒力因子，不同的寄生虫利用它来使宿主分子去磷酸化。本研究的目的是对寄生在海洋硬骨鱼类的 3 种旋口虫（Uronema marinum、Miamiensis avidus 和 Parauronema virginianum）的 AcP 进行特征描述。我们在 3 种寄生虫中鉴定出了 AcP 活性（pH5.2），并发现其具有不同的细胞分布。纤毛虫裂解物的天然凝胶电泳显示，M. avidus 存在 1 种高分子量 AcP 活性带（对酒石酸盐敏感），U. marinum 存在多个低分子量 AcP，而 P. virginianum 仅存在 1 个低分子量带（对酒石酸盐有抗性）。旋口虫 AcP 被酪氨酸蛋白磷酸酶的特异性抑制剂抑制。饥饿时 AcP 减少，但暴露于皮肤黏液后会迅速重新激活。石首鱼（Polyprion oxygeneios）外周血白细胞（PBL）和红细胞（更少量）的 AcP 活性也增加。蛋白酪氨酸磷酸酶 PTP1b 主要在 M. avidus 的质膜中被检测到，吞噬石首鱼 PBL 会使其表达上调。从实验感染石首鱼中恢复的 M. avidus 比注射悬浮液中的 PTP1b 表达水平更高。本研究结果强调了 PTP 在食源性寄生虫及其与鱼类宿主因子相互作用中的重要性。
