斑节对虾病原菌胞外产物的致病性研究

由养殖濒死病虾体内分离的副溶血弧菌(2019#)、溶藻弧菌(4302#)和嗜水气单胞菌(1003#)培养液中分别提取了胞外产物,测定了酶成分,定量分析了蛋白酶及磷酸酯酶的活性.用细菌胞外产物粗提液对斑节对虾进行致死试验,戊二醛固定致死对虾的肝组织,电镜观察了斑节对虾肝组织的超微病变,初步探讨了三株细菌胞外产物诱发虾病的病理.

Studies on pathogenesis of extracellular products from pathogenetic bacteria in Penaeus monodon Fabrivius

The extracellular products of Vibrio parahaemolyticus, V. alginolyticus and Aeromonas hydrophila, which were isolated from diseased Penaeus monodon in Tong an from June to August 1997, are extracted and investigated. Composition of extracellular enzymes from these three bacteria is detected. Among them, protease and phospholiase, including both acidic phospholiase and alkine phospholiase, are chosen to do quantitative analysis on their activities. These three kinds of the above enzymes extracted from cultures of V. parahaemolyticus are more active than those of the others. Bacterial extracellular products are used to do lethal experiments by injecting to the healthy P. monodon. Conforming to the result of activity of protease and phospholiase, lethal action of V. parahaemolyticus is the strongest and that of V. alginolyticus is the weakest. The pathological variations of dying shrimps livers in the lethal experiments are observed by transmit electron microscope (TEM). Cells of those shrimps livers show to be destroyed at different extents, for example, nuclear core of some cells disappeared and nuclear membrane are wrecked, mitochondria are destroyed, even the whole cell is disintegrated. It is showed that not only dxtracellular products of these three strains are poisonous and could be mortal to shrimps, but also the activities of protease and phospholiase in extracellular products of pathogen are related to toxicity of these three strains.