Rapid divergence of two classes of Haemophilus ducreyi.
Rapid divergence of two classes of Haemophilus ducreyi.
复制标题
两类杜克雷嗜血杆菌的快速分化。
DOI：
10.1128/jb.01400-10
复制
发表时间：
2011
影响因子：
3.2
通讯作者：
Humphreys,TriciaL
中科院分区：
文献类型：
--
作者：
Ricotta,EmilyE;Wang,Nan;Cutler,Robin;Lawrence,JeffreyG;Humphreys,TriciaL
Haemophilus ducreyi, the etiologic agent of chancroid, expresses variants of several key virulence factors. While previous reports suggested that H. ducreyi strains formed two clonal populations, the differences between, and diversity within, these populations were unclear. To assess their variability, we examined sequence diversity at 11 H. ducreyi loci, including virulence and housekeeping genes, augmenting published data sets with PCR-amplified genes to acquire data for at least 10 strains at each locus. While sequences from all 11 loci place strains into two distinct groups, there was very little variation within each group. The difference between alleles of the two groups was variable and large at 3 loci encoding surface-exposed proteins (0.4 <KS< 1.3, whereKSis divergence at synonymous sites) but consistently small at genes encoding cytoplasmic or periplasmic proteins (KS< 0.09). The data suggest that the two classes have recently diverged, that recombination has introduced variant alleles into at least 3 distinct loci, and that these alleles have been confined to one of the two classes. In addition, recombination is evident among alleles within, but not between, classes. Rather than clones of the same species, these properties indicate that the two classes may form distinct species.
