González-Fraga Sol, Pichel Mariana, Binsztein Norma, Johnson Judith A, Morris John Glenn, Stine Oscar Colin
Instituto Nacional de Enfermedades Infecciosas-ANLIS Carlos G. Malbrán, Buenos Aires, Argentina.
FEMS Microbiol Lett. 2008 Sep;286(1):32-8. doi: 10.1111/j.1574-6968.2008.01251.x.
In Gram-negative bacteria, the O-antigen-encoding genes may be transferred between lineages, although mechanisms are not fully understood. To assess possible lateral gene transfer (LGT), 21 Argentinean Vibrio cholerae O-group 1 (O1) isolates were examined using multilocus sequence typing (MLST) to determine the genetic relatedness of housekeeping genes and genes from the O1 gene cluster. MSLT analysis revealed that 4.4% of the nucleotides in the seven housekeeping loci were variable, with six distinct genetic lineages identified among O1 isolates. In contrast, MLST analysis of the eight loci from the O1 serogroup region revealed that 0.24% of the 4943 nucleotides were variable. A putative breakpoint was identified in the JUMPstart sequence. Nine conserved nucleotides differed by a single nucleotide from a DNA uptake signal sequence (USS) also found in Pastuerellaceae. Our data indicate that genes in the O1 biogenesis region are closely related even in distinct genetic lineages, indicative of LGT, with a putative DNA USS identified at the defined boundary for the DNA exchange.
在革兰氏阴性菌中，编码O抗原的基因可能在谱系间转移，尽管其机制尚未完全明确。为评估可能的横向基因转移（LGT），对21株阿根廷霍乱弧菌O1群（O1）分离株进行了多位点序列分型（MLST），以确定管家基因和O1基因簇基因的遗传相关性。MSLT分析显示，七个管家基因座中4.4%的核苷酸是可变的，在O1分离株中鉴定出六个不同的遗传谱系。相比之下，对O1血清群区域八个基因座的MLST分析显示，4943个核苷酸中有0.24%是可变的。在JUMPstart序列中鉴定出一个假定的断点。九个保守核苷酸与巴斯德氏菌科中也发现的DNA摄取信号序列（USS）仅相差一个核苷酸。我们的数据表明，即使在不同的遗传谱系中，O1生物合成区域的基因也密切相关，这表明存在LGT，并在确定的DNA交换边界处鉴定出一个假定的DNA USS。
