Guasp C, Moore E R, Lalucat J, Bennasar A
Int J Syst Evol Microbiol. 2000 Jul;50 Pt 4:1629-1639. doi: 10.1099/00207713-50-4-1629.
Bacteria identified and classified as Pseudomonas stutzeri, on the basis of traditional criteria, are recognized to be markedly heterogeneous, such that a systematic phenotypic characterization has not been correlated with genotypic groupings (i.e. genomovars) based upon DNA-DNA similarities. The internally transcribed 16S-23S rDNA spacer (ITS1) regions of P. stutzeri were analysed with respect to the ability of these nucleic acid regions to differentiate and identify the genomic groups (i.e. genomovars) of P. stutzeri. The ITS1s of 34 strains of P. stutzeri were amplified by PCR and the PCR product was subjected to RFLP analysis, which allowed the differentiation and identification of the strains to their respective genomovars. Sequence determination and analysis of ITS1s supported further the results obtained by RFLP, i.e. nucleotide signatures were identified in strains belonging to different genomovars. The ITS1s of all strains of P. stutzeri contained the tandem tRNA(Ile)/tRNA(Ala) genes and did not exhibit distinct sequence heterogeneity between different operons of a strain. Phylogenetically informative variable sites were located, exclusively, in non-coding regions. The results of the RFLP and sequence analysis of ITS1s supported and correlated with the phylogenetic relationships estimated from 16S rRNA gene sequence comparisons and DNA-DNA hybridizations, offering an alternative tool for genomovar and species differentiation.
根据传统标准鉴定并归类为斯氏假单胞菌的细菌被认为具有明显的异质性，以至于基于DNA-DNA相似性的系统表型特征尚未与基因型分组（即基因组变种）相关联。对斯氏假单胞菌的内部转录16S-23S rDNA间隔区（ITS1）进行了分析，以研究这些核酸区域区分和鉴定斯氏假单胞菌基因组组（即基因组变种）的能力。通过PCR扩增了34株斯氏假单胞菌的ITS1，并对PCR产物进行了RFLP分析，从而能够将菌株区分并鉴定到各自的基因组变种。ITS1的序列测定和分析进一步支持了RFLP获得的结果，即在属于不同基因组变种的菌株中鉴定出了核苷酸特征。所有斯氏假单胞菌菌株的ITS1都包含串联的tRNA（Ile）/tRNA（Ala）基因，并且在一个菌株的不同操纵子之间未表现出明显的序列异质性。系统发育信息丰富的可变位点仅位于非编码区。ITS1的RFLP和序列分析结果支持并与基于16S rRNA基因序列比较和DNA-DNA杂交估计的系统发育关系相关，为基因组变种和物种区分提供了一种替代工具。
