Laboratory of Fish Diseases, Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Japan.
Laboratory of Fish Diseases, Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Japan.
J Invertebr Pathol. 2022 Jan;187:107705. doi: 10.1016/j.jip.2021.107705. Epub 2021 Dec 14.
The protozoan parasite Perkinsus olseni is a major pathogen of marine mollusks. A large number of zoospores (the most infective stage) is required to experimentally examine the transmission and invasion processes of this parasite, but the conventional zoosporulation method in seawater is inefficient. A recent study found that P. olseni zoosporulation was highly enhanced in a nutrient-rich medium which was developed for trophozoite proliferation in Perkinsus. Here, we examined the effect of each medium component on P. olseni zoosporulation and found that lipids enhanced zoosporulation. Moreover, zoospores failed to develop into trophozoites in seawater supplemented with lipids, indicating that this zoosporulation method using seawater supplemented with lipids is ideal for preparing a large number of P. olseni zoospores for various biological assays. Lipid supplementation also significantly enhanced zoosporulation in P. honshuensis, P. chesapeaki, and P. marinus, although the enhancing effect of the lipid supplementation varied by species. Considering the limited availability of lipids in the sea water column, our findings suggest that Perkinsus zoosporulation likely occurs mainly in the vicinity of hosts (not in the sea water column), such as in the mantle cavity or on the body surface of mollusk hosts.
原生动物寄生虫 Perkinsus olseni 是海洋软体动物的主要病原体。为了实验研究寄生虫的传播和入侵过程，需要大量的游动孢子（最具感染性的阶段），但传统的海水中游动孢子形成方法效率低下。最近的一项研究发现，在 Perkinsus 滋养体增殖的营养丰富的培养基中，P. olseni 的游动孢子形成得到了高度增强。在这里，我们研究了每种培养基成分对 P. olseni 游动孢子形成的影响，发现脂质增强了游动孢子形成。此外，在添加脂质的海水中，游动孢子无法发育成滋养体，这表明这种使用添加脂质的海水的游动孢子形成方法非常适合为各种生物学测定制备大量 P. olseni 游动孢子。脂质补充还显著增强了 P. honshuensis、P. chesapeaki 和 P. marinus 的游动孢子形成，尽管脂质补充的增强效果因物种而异。考虑到海水中脂质的有限可用性，我们的发现表明 Perkinsus 游动孢子的形成可能主要发生在宿主附近（而不是在海水中），例如在套膜腔或软体动物宿主的体表。
