对钉螺具有毒性作用细菌的分离及初步鉴定

目的筛选对钉螺具有毒性作用的细菌及其毒素成分.方法收集濒死钉螺及其周围的土壤样本,分离其中的细菌.经发酵制备细菌的发酵上清、细菌裂解产物.通过杀螺毒性试验测定细菌发酵上清液、细菌的裂解产物及细菌对钉螺的毒性作用.结果从濒死钉螺及土壤样本中分离到104株细菌,经初步鉴定,这些细菌包括革兰氏阳性球菌、革兰氏阳性杆菌,革兰氏阴性球菌、革兰氏阴性杆菌.细菌PY1-1, PY3-3, PY1-2-1, PY7-2, PY3-5, PY19-3, PY2-2-2, PY8-2-2, PY8-4, PY16-1的发酵上清液、细菌裂解产物及细菌菌体对钉螺均具有不同程度的毒性作用,其中细菌PY1-1, PY7-2, PY3-5, PY19-3, PY2-2-2, PY8-2-2, PY16-1的发酵上清液对钉螺的杀灭作用均〉50.0%.结论对钉螺具有毒性作用的细菌已经被分离出,为进一步鉴定对钉螺具有毒性作用的单一细菌成分奠定了基础.

Isolation and preliminary identification of bacteria which are poisonous to Oncomelania hupensis

Objective To screen the bacteria and its components which are toxic to Oncomelania hupensis. Methods The samples of Oncomelania hupensis on the point of death and the soil around the snails were collected. The bacteria existing in the snails and soil were isolated and identified by using regular methods. After being fermented, the toxicity of the bacterium components including the ferment supernatant, split products and bacteria to the snail were tested by the toxicity test. Results Totally, 104 strains of bacteria were isolated from the snails and soil samples, which included Gram positive cocci or bacilli, Gram negative cocci or bacilli. The fermenting supernatant, splitting products and 10 strains of bacteria showed different level of toxicity against the snail respectively. All the fermenting supernatant of bacterium PY1-1, PY7-2, PY3 5, PY19-3, PY2-2-2, PY8-2-2, PY16-1 could kill more than 50 percent of snails. Conclusion The bacteria which are poisonous to snails have been isolated that make a good basis for identifying single toxic component against snails.