Department of Microbiology, University of Texas Southwestern, Medical Center, Dallas, Texas, USA.
Infect Immun. 2012 Mar;80(3):982-95. doi: 10.1128/IAI.05918-11. Epub 2011 Dec 19.
Young adult chinchillas were atraumatically inoculated with Moraxella catarrhalis via the nasal route. Detailed histopathologic examination of nasopharyngeal tissues isolated from these M. catarrhalis-infected animals revealed the presence of significant inflammation within the epithelium. Absence of similar histopathologic findings in sham-inoculated animals confirmed that M. catarrhalis was exposed to significant host-derived factors in this environment. Twenty-four hours after inoculation, viable M. catarrhalis organisms were recovered from the nasal cavity and nasopharynx of the animals in numbers sufficient for DNA microarray analysis. More than 100 M. catarrhalis genes were upregulated in vivo, including open reading frames (ORFs) encoding proteins that are involved in a truncated denitrification pathway or in the oxidative stress response, as well as several putative transcriptional regulators. Additionally, 200 M. catarrhalis genes were found to be downregulated when this bacterium was introduced into the nasopharynx. These downregulated genes included ORFs encoding several well-characterized M. catarrhalis surface proteins including Hag, McaP, and MchA1. Real-time reverse transcriptase PCR (RT-PCR) was utilized as a stringent control to validate the results of in vivo gene expression patterns as measured by DNA microarray analysis. Inactivation of one of the genes (MC ORF 1550) that was upregulated in vivo resulted in a decrease in the ability of M. catarrhalis to survive in the chinchilla nasopharynx over a 3-day period. This is the first evaluation of global transcriptome expression by M. catarrhalis cells in vivo.
幼年沙鼠经鼻腔途径被无创伤性接种了卡他莫拉菌。从这些感染了卡他莫拉菌的动物的鼻咽组织中分离出的组织进行详细的组织病理学检查，发现上皮内存在明显的炎症。在假接种动物中未发现类似的组织病理学发现，证实了在这种环境中，卡他莫拉菌暴露于大量宿主来源的因素。接种后 24 小时，从动物鼻腔和鼻咽中回收了足够用于 DNA 微阵列分析的活的卡他莫拉菌。在体内有超过 100 个卡他莫拉菌基因上调，包括编码参与截断反硝化途径或氧化应激反应的蛋白质的开放阅读框 (ORF)，以及几个假定的转录调节剂。此外，当这种细菌被引入鼻咽时，发现 200 个卡他莫拉菌基因下调。这些下调的基因包括编码几种特征明确的卡他莫拉菌表面蛋白的 ORF，如 Hag、McaP 和 MchA1。实时逆转录 PCR (RT-PCR) 被用作严格的对照，以验证 DNA 微阵列分析测量的体内基因表达模式的结果。体内上调的一个基因 (MC ORF 1550) 的失活导致卡他莫拉菌在沙鼠鼻咽中的存活能力在 3 天内下降。这是卡他莫拉菌细胞在体内进行全转录组表达的首次评估。
