Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Environ Microbiol. 2010 Nov;12(11):2977-87. doi: 10.1111/j.1462-2920.2010.02274.x.
The O-antigen is a highly diverse structure expressed on the outer surface of Gram-negative bacteria. The products responsible for O-antigen synthesis are encoded in the wbe region, which exhibits extensive genetic diversity. While heterogeneous O-antigens are observed within Vibrio species, characterization of these structures has been devoted almost exclusively to pathogens. Here, we investigate O-antigen diversity among coastal marine Vibrio splendidus-like isolates. The wbe region was first identified and characterized using the sequenced genomes of strains LGP32, 12B01 and Med222. These regions were genetically diverse, reflective of their expressed O-antigen. Additional isolates from physically distinct habitats in Plum Island Estuary (MA, USA), including within animal hosts and on suspended particles, were further characterized based on multilocus sequence analysis (MLSA) and O-antigen profiles. Results showed serotype diversity within an ecological setting. Among 48 isolates which were identical in three MLSA genes, 41 showed gpm genetic diversity, a gene closely linked to the wbe locus, and at least 12 expressed different O-antigen profiles further suggesting wbe genetic diversity. Our results demonstrate O-antigen hyper-variability among these environmental strains and suggest that frequent lateral gene transfer generates wbe extensive diversity among V. splendidus and its close relatives.
O 抗原是革兰氏阴性细菌外表面高度多样化的结构。负责 O 抗原合成的产物编码在 wbe 区域，该区域表现出广泛的遗传多样性。虽然在弧菌属中观察到了异质的 O 抗原，但这些结构的特征主要集中在病原体上。在这里，我们研究了沿海海洋灿烂弧菌样分离株的 O 抗原多样性。首先使用 LGP32、12B01 和 Med222 菌株的测序基因组来鉴定和表征 wbe 区域。这些区域具有遗传多样性，反映了它们表达的 O 抗原。根据多位点序列分析 (MLSA) 和 O 抗原图谱，进一步对来自马萨诸塞州普卢姆岛河口（美国）不同物理栖息地的其他分离株进行了特征描述，包括动物宿主和悬浮颗粒上的分离株。结果显示在生态环境中存在血清型多样性。在 48 株在三个 MLSA 基因上完全相同的分离株中，有 41 株显示 gpm 遗传多样性，这是一个与 wbe 基因座紧密相关的基因，至少有 12 株表达了不同的 O 抗原图谱，这进一步表明 wbe 基因具有遗传多样性。我们的结果表明这些环境菌株的 O 抗原具有高度可变性，并表明频繁的横向基因转移导致灿烂弧菌及其近亲的 wbe 广泛多样性。
