南方九孔鲍培苗过程中潜在致病菌胞外产物的分析

从广东汕尾一养殖场鲍苗掉板池中(包括水、藻膜和变白鲍苗)分离筛选到105株菌,并对之进行了致病毒力因子(胞外酶及溶血作用)的分析,同时应用PCR对溶血毒素的归属进行了初步的探讨,采用API对菌株进行了种类鉴定。结果表明,105株菌中,仅35株菌具有较强的分泌胞外蛋白酶、明胶酶和脂肪酶的能力,尤其以菌株1、2、3、5、9以及16相对强大。在此35株菌中,85.6%的菌株(3035株)表现出溶血现象,但仅16株菌的TlhPCR呈阳性。API鉴定表明,35株菌中弧菌约占50%,溶藻弧菌又占弧菌的70%。研究结果揭示,和其它菌株相比,分离自变白鲍苗的6株溶藻弧菌(菌株1、2、3、5,13和16)和2株副溶血弧菌(菌株9和21)具有较强的分泌胞外酶和或溶血的能力,意味着极有必要对其作进一步的研究,以观测它们对鲍苗的影响。

Studies on extracellular virulent factors produced by potential pathogenic bacteria isolated from Abalone postlarvae and biofilms

To find out the potential pathogen(s) that caused massive death of abalone postlarvae(Haliotis diversicolor supertesta)in Southern China, 105 bacterial strains were isolated from the water, whitened postlarvae and their biofilms of an abalone farm in Guangdong Province. Extra-cellular protease, gelatinase, lipase as well as haemolysis tests were performed on them. Lysophospholipase (Tlh)-targeted PCR was also carried out in order to reveal if the haemolysis caused by bacterial strains were related to Tlh. Results showed that 35 out of 105 strains possessed extra-cellular enzymatic abilities and strains 1, 2, 3, 5, 9 and 16 were the most powerful ones of all. Among these 35 strains, 85.6% strains (30/35) possessed haemolytic activities on goat blood agar and specific PCR revealed that 16 strains were PCR positive, indicating that they contained Tlh genes. In order to identify these strains, API 20 E strips were employed and results indicated that 50% were vibrios, among them Vibrio alginolyticus composed 70% of the vibrio population. In conclusion, compared to other strains, 6 Vibrio alginolyticus(strain 1, 2, 3, 5, 13, and 16 ) and 2 Vibrio parahaemolyticus (strain 9 and 21) which all were isolated from whitened abalone postlarvae, warrant further studies due to their better abilities in extra-cellular enzyme(s) production and/or haemolytic activities.