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

从河口网虾腹足类中检出耐热的副溶血性弧菌的直接溶血素(TdH)产生菌。成虫的血淋巴中含有成熟的血细胞，而幼虫的血淋巴中含有未成熟的血细胞，这些血细胞在化学上被副溶血弧菌吸引，只有在软体动物血浆存在的情况下才能吞噬副溶血弧菌。这些证据表明，即使在血细胞存在的情况下，副溶血性弧菌也可以在幼虫的消化道中定植。在本研究中，我用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳法和凝胶扩散法分析了副溶血弧菌在腹足类消化道的定植水平和腹足类血浆蛋白的组成。在20ﾟC，盐度为20*的循环人工海水中，摄食了10^5cfu/g的副溶血弧菌D-3和非产生菌R-13和N-18的成虫和幼虫保持了长达21天的时间。在成人中，所有菌株在21天内均降至10^0cfu/g水平。在幼虫中，D-3菌株在10^4~10^5cfu/g的水平下存活至少21d，而菌株R-13和N-18在第21天下降到10^2~10^1cfu/g的水平。除副溶血弧菌外，反枝线虫和两种海洋网虫的血浆分别用各自血浆的抗血清进行了SDS-PAGE和凝胶扩散。在SDS-PAGE中可见3种腹足类动物共有的主要条带和3种腹足类动物共有的主要条带。

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.