硇洲岛海胆可培养细菌的多样性

摘要

[Objective] To investigate the diversity of culturable bacteria isolated from the sea urchin Hemicentrotus pulcherrimus collected from a tidal flat of Naozhou Island(20°52'N～20°56'N 110°33'E～110°38'E),Leizhou Bay,South China Sea,China. [Methods] Bacteria were isolated from the sample by using conventional culture-dependent method and then investigated by using phylogenetic analysis based on 16S rRNA gene sequence comparisons.[Results ]We isolated 106 bacterial strains from the sample on media (Difco marine 2216;International Streotomyces Project medium 2;nutrient;sea water and humic acid agars) supplemented with 0～2 mol/L NaCl.On the basis of morphological;physiological and biochemical characteristics;we selected 34 strains to perform a phylogenetic analysis based on 16S rRNA gene sequences.Our results showed that 34 isolates represented 21 species; belonging to 17 genera (Alteromonas, Bacillus, Brachybacterium , Brevibacterium, Halobacillus,Halomonas, Nocardiopsis , Oceanobacillus, Piscibacillus, Planococcus, Pontibadllus, Pseudoalteromonas, Pseudonocardia,Sahnicoccus, Sahnwibrio, Staphylococcus, Vibrio, Virgibacillus) of 10 families (Alteromonadaceae, Bacillaceae,Brevibactenaceae, Dermabacteraceae,Halomonadaceae,Planococcaceae,Pseudoalteromonadaceae,Pseudonocardiaceae;Nocardiopsaceae,Staphylococcaceae,Vibnonaceae)in three phylogenetic groups (Actinobactena,Firmicutes,GammaProteobactena).The most abundant and diverse isolates were within the phylum Firmicutes (58.8%)and the subphylum Gamma-Proteobactena (26.5% ).The phylogenetic distance matrix results suggested that there were obvious genetic divergences between most isolates and their closestly related type strains (16S rRNA gene sequence similarities ranged from 99.6 to 99.9%), and that, out of 34 isolates, at least 5 strains (JSM 076033, JSM 076056, JSM 076093, JSM 078063, JSM 078169) could represent 5 potential new species within 5 characterized genera (Jeotgalicoccus,Pontibacillus,Halomonas,Bacillus, Sporosardna),in which the descriptions of 3 novel species [Jeotgalicoccus marinus (type strain,JSM 076033),Pontibacillus halophilus (JSM 076056),Halomonas zhanjiangensis (JSM 078169)] have been published in IJSEM (International Journal of Systematic and Evolutionary Microbiology).[Conclusion]The results presented above showed that there are abundant bacteria diversity in the sea urchin Hemicentrotus pulcherrimus collected from Naozhou Island.%[目的]研究南海硇洲岛马粪海胆(Hemicentrotus pulcherrimus)培养细菌多样性.[方法]采用纯培养法和基于16S rRNA基因序列的系统发育分析对样品中细菌(含放线菌)多样性进行研究.[结果]用补充0～2.0 mol/L NaCl的MA、ISP 2、NA、SWA和HAA培养基从海胆样品中分离到106株细菌菌株,根据形态观察和部分生理生化实验结果去冗余,选取34个代表性菌株进行基于16S rRNA基因序列的系统发育多样性分析.结果表明,这些分离菌株代表21个物种,属于3个大的系统发育类群(Firmicutes,Aetinobacteria,Gamma-Proteobacteria)的10个科、17个属.多数菌株属于Firmicutes门(21株,58.8%)和Actinobacteria门(9株,26.5%).大多数菌株与其系统发育关系最密切的已知物种的典型菌株之间存在一定的遗传差异(16S rRNA基因序列相似性为99.6%～99.9%),其中至少有5个菌株(JSM 076033,JSM 076056,JSM 076093,JSM 078063和JSM 078169)代表潜在的新分类单元(potential new taxa).[结论]研究结果表明,南海硇洲岛海胆中存在较为丰富的细菌多样性,并且潜藏着较多的新的微生物类群(物种).