Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada.
Infect Immun. 2011 Jun;79(6):2423-9. doi: 10.1128/IAI.01169-10. Epub 2011 Apr 4.
Bordetella pertussis, Bordetella parapertussis, and Bordetella bronchiseptica cause respiratory tract disease in mammals, whereas Bordetella avium causes respiratory tract disease in avian hosts. While there are striking similarities between the diseases caused by the mammalian- and avian-adapted bordetellae, differences at the genetic level may account for their different host tropisms. Bacterial pathogens utilize the chaperone-usher pathway to assemble extracellular multisubunit structures (fimbriae) that play a role in virulence. Fimbriae of the mammalian bordetellae mediate attachment to the host respiratory epithelium. They are assembled by a single chaperone/usher system encoded by the fimbrial biogenesis operon fimA-D. B. avium contains a homologous fimbrial operon (BAV1965-1962), and we report here the functionality of this locus. Reverse transcription (RT)-PCR and quantitative PCR analyses demonstrated that transcription of the locus is regulated by temperature. By immuno-transmission electron microscopy (TEM), BAV1965-containing fimbriae were observed on bacteria grown at 37°C but not those grown at 22°C. A mutant in which BAV1965-1962 was deleted displayed significantly lower levels of adherence to turkey tracheal rings than the wild type. Thus, the BAV1965-1962 fimbrial locus is functional, its expression is regulated in response to temperature, and it produces fimbriae involved in adherence to host respiratory tract tissue.
百日咳博德特氏菌、副百日咳博德特氏菌和支气管败血博德特氏菌引起哺乳动物呼吸道疾病，而鸟型博德特氏菌引起禽类宿主呼吸道疾病。虽然哺乳动物和禽源博德特氏菌引起的疾病有明显的相似之处，但遗传水平的差异可能解释了它们不同的宿主嗜性。细菌病原体利用伴侣菌毛途径组装细胞外多亚基结构（菌毛），这些结构在毒力中起作用。哺乳动物博德特氏菌的菌毛介导与宿主呼吸道上皮的附着。它们由单个伴侣/菌毛系统组装而成，该系统由菌毛生物发生操纵子 fimA-D 编码。禽型博德特氏菌含有同源菌毛操纵子（BAV1965-1962），我们在此报告该基因座的功能。逆转录（RT）-PCR 和定量 PCR 分析表明，该基因座的转录受温度调节。通过免疫透射电子显微镜（TEM）观察到，在 37°C 下生长的细菌含有 BAV1965 的菌毛，但在 22°C 下生长的细菌则没有。与野生型相比，缺失 BAV1965-1962 的突变体对火鸡气管环的粘附水平明显降低。因此，BAV1965-1962 菌毛基因座是功能性的，其表达受温度调节，并且产生参与粘附宿主呼吸道组织的菌毛。
