Freitas Dulcecleide B, Reis Mariana P, Lima-Bittencourt Cláudia I, Costa Patrícia S, Assis Paulo S, Chartone-Souza Edmar, Nascimento Andréa M A
Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
BMC Res Notes. 2008 Oct 17;1:92. doi: 10.1186/1756-0500-1-92.
Molecular studies of Bacillus diversity in various environments have been reported. However, there have been few investigations concerning Bacillus in steel plant environments. In this study, genotypic and phenotypic diversity and phylogenetic relationships among 40 bacterial isolates recovered from steel plant waste were investigated using classical and molecular methods.
16S rDNA partial sequencing assigned all the isolates to the Bacillus genus, with close genetic relatedness to the Bacillus subtilis and Bacillus cereus groups, and to the species Bacillus sphaericus. tDNA-intergenic spacer length polymorphisms and the 16S-23S intergenic transcribed spacer region failed to identify the isolates at the species level. Genomic diversity was investigated by molecular typing with rep (repetitive sequence) based PCR using the primer sets ERIC2 (enterobacterial repetitive intergenic consensus), (GTG)5, and BOXAIR. Genotypic fingerprinting of the isolates reflected high intraspecies and interspecies diversity. Clustering of the isolates using ERIC-PCR fingerprinting was similar to that obtained from the 16S rRNA gene phylogenetic tree, indicating the potential of the former technique as a simple and useful tool for examining relationships among unknown Bacillus spp. Physiological, biochemical and heavy metal susceptibility profiles also indicated considerable phenotypic diversity. Among the heavy metal compounds tested Zn, Pb and Cu were least toxic to the bacterial isolates, whereas Ag inhibited all isolates at 0.001 mM.
Isolates with identical 16S rRNA gene sequences had different genomic fingerprints and differed considerably in their physiological capabilities, so the high levels of phenotypic diversity found in this study are likely to have ecological relevance.
已有关于不同环境中芽孢杆菌多样性的分子研究报道。然而，针对钢铁厂环境中芽孢杆菌的研究较少。在本研究中，运用经典方法和分子方法对从钢铁厂废料中分离得到的40株细菌的基因型和表型多样性以及系统发育关系进行了研究。
16S rDNA部分测序将所有分离株归为芽孢杆菌属，与枯草芽孢杆菌和蜡样芽孢杆菌群以及球形芽孢杆菌在遗传上密切相关。tDNA基因间隔区长度多态性分析以及16S - 23S基因间隔转录区分析未能在种水平上鉴定这些分离株。通过使用ERIC2（肠杆菌重复基因间共有序列）、(GTG)5和BOXAIR引物对基于rep（重复序列）的PCR进行分子分型来研究基因组多样性。分离株的基因型指纹图谱反映出种内和种间的高度多样性。使用ERIC - PCR指纹图谱对分离株进行聚类与从16S rRNA基因系统发育树得到的结果相似，表明前一种技术作为一种简单且有用的工具来检测未知芽孢杆菌属间关系的潜力。生理、生化和重金属敏感性谱也表明存在相当大的表型多样性。在所测试的重金属化合物中，锌、铅和铜对细菌分离株的毒性最小，而银在0.001 mM时抑制所有分离株。
具有相同16S rRNA基因序列的分离株具有不同的基因组指纹图谱且生理能力差异很大，因此本研究中发现的高水平表型多样性可能具有生态相关性。
