摘要
从海水养殖水体中防腐钢片的微生物黏膜上分离筛选到一株细菌,命名为DL2。采用琼脂扩散法进行体外抑菌实验,测定其抑菌谱,发现菌株DL2具有较广泛的抑菌谱,并且对致病性弧菌表现出较强的抑菌作用。通过常规生理生化研究和细菌鉴定系统测试,发现菌株DL2属于革兰氏阴性菌,短杆状,具极生单鞭毛,菌落呈褐色,能产生浅褐色扩散性色素,测试结果表明,菌株DL2与Phaeobacter属细菌的特征非常相似。为了进一步确定菌株DL2的分类学地位,测定了其16S rRNA基因序列,与相关细菌种属相应序列的同源性进行比较并构建了系统关系树,结果显示,菌株DL2与Phaeobacter inhibens的亲缘关系最近,相似性达99.8%,与Phaeobacter gallaeciensis相似性达99.1%。综合上述结果,菌株DL2可鉴定为Phaeobacter inhibens,同时可以将其作为潜在的海洋有益菌应用于水产养殖中。
A bacterium DL2 was isolated from microbial biofilms of antiseptic steel pieces in aquatic water.The inhibitory activity of DL2 was tested by using agar diffusion method on 2216E plates.Bacterium DL2 showed wide inhibitory spectrum,especially for pathogenic Vibrio sp..To identify DL2,its morphological,physiological and biochemical properties were tested,and API 20E system was applied in the bacterial identification.Morphological observation results showed that the colonies of strain DL2 on 2216E agar became brown after 48 h.The bacterium was gram-negative which had single polar flagellum and had the capability to produce brownish diffusible pigment.The organism was found to be catalase-positive,oxidase-positive,but negative for amylase,gelatinase and tweenase.It could not reduce nitrate and could not utilize citrate as sole carbon source.The results showed that the strain DL2 was similar to Phaeobacter inhibens in most of the phenotypes.To investigate the phylogenetic position of this bacterium 16S rRNA gene of strain DL2 was sequenced and compared with those of related strains.The homology of 16S rRNA gene between strain DL2 and Phaeobacter inhibens was 99.8%.Phylogenetic tree was constructed by using neighbour-joining method.Strain DL2 and the strain Phaeobacter inhibens LMG 22475T(access no.AY177712) consistently formed a monophyletic clade,which revealed that strain DL2 shared the most similarity to Phaeobacter inhibens.Base on the inhibitory activity,morphological,physiological and phylogenetic analysis,DL2 was identified as Phaeobacter inhibens.It can be used in aquaculture as a potential probiotics based on its inhibitory activity.
出处
《中国水产科学》
CAS
CSCD
北大核心
2007年第6期996-1003,共8页
Journal of Fishery Sciences of China
基金
国家高技术研究发展计划(863计划)项目(2004AA626090)
国家自然科学基金项目(30200209)
作者简介
董秀娟(1979-),女,硕士研究生,主要从事海洋微生物学方面的研究.E-mail:dongxj08@163.com 李筠(1967-),女,教授.Tel:0532-82032957;E-mail:yunlisun@ouc.edu.cn 通讯作者
