Recognition of thermostable direct hemolysin-producing strains of V.parahaemolyticus by C.retropictus

从河口背腹足动物中检出一株耐热直接溶血素（TDH）副溶血性弧菌。成虫的血淋巴中含有成熟血细胞，而幼虫的血淋巴中含有未成熟血细胞，这些未成熟血细胞会被副溶血性弧菌吸引，只有在软体动物血浆存在的情况下才会被吞噬。这些证据表明，即使在有血细胞存在的情况下，副溶血性弧菌也能在幼虫的消化道中定植。在这项研究中，我用SDS-PAGE和凝胶扩散分析了副溶血性弧菌在腹足动物消化道中的定植水平，以及腹足动物血浆蛋白的组成。以10^5 cfu/g的产tdh菌株D-3和非产tdh菌株R-13和n- 18为食的逆行梭状芽孢杆菌成虫和幼虫，在20 <s:1> / C、20*盐度的循环水中维持21天。在成人中，所有菌株在21天内降至10^0 cfu/g的水平。在幼体中，菌株D-3在10^4-10^5 cfu/g水平下存活至少21天，而菌株R-13和N-18在第21天降至10^2-10^1 cfu/g水平。因此，产tdh的菌株会通过反复通过幼鱼的消化道而集中在河口。对除副溶血性弧菌外的逆转录弧菌和白色弧菌、日本弧菌两种海洋奈利菌的血浆进行了SDS-PAGE和凝胶扩散实验。SDS-PAGE显示3种腹足动物共有的主带和不同的主带。凝胶扩散中可以看到每种腹足动物特有的抗原和三种腹足动物共有的抗原。

Thermostable direct hemolysin (TDH)-producing strains of Vibrio parahaemolyticus were detected from an estuarine Neritid gastropod, Clithon retropictus. Adult C.retropictus contains mature hemocytes in the hemolymph while juvenile one contains immature hemocytes which is attracted chemotactically to V.parahaemolyticus and phagocytize it only in the presence of molluscan plasma. These evidences suggest that V.parahaemolyticus could colonize in the alimentary tract of the juveniles even in the presence of hemocytes. IN this study, I analyzed the levels of V.parahaemolyticus strains to colonize in the alimentary tract of the gastropod and also composition of plasma proteins of the gastropod with SDS-PAGE and gel diffusion.Adult and juvenile C.retropictus ingested with TDH-producing strain D-3 and TDH-non-producing strains R-13 and N-18at a level of 10^5 cfu/g were maintained in UV-irradiated recirculating artificial seawater with a salinity of 20* at 20ﾟC for up to 21 days. In adults, all strains decreased to a level of 10^0 cfu/g within 21 days. In juveniles, strain D-3 survived at a level of 10^4-10^5 cfu/g for at least 21 days while atrains R-13 and N-18 decreased to the level of 10^2-10^1 cfu/g at the 21st day. Thus, TDH-producing strains would be concentrated in estuaries by the repeated passes through the alimentary tract of the juveniles.Plasmas of C.retropictus and two marine Neritids, Nerita albicilla and Heminerita japonica, exclusive of V.parahaemolyticus, were adapted to SDS-PAGE and gel diffusion with antisera of respective plasma. Main bands common to 3 gastropods and those different each other were seen in SDS-PAGE.Antigens specific to each gastropod and those common in three gastropods were seen in gel diffusion.