The cell envelope is a multilayered structure that insulates the interior of bacterial cells from an often chaotic outside world. Common features define the envelope across the bacterial kingdom, but the molecular mechanisms by which cells build and regulate this critical barrier are diverse and reflect the evolutionary histories of bacterial lineages. Intracellular pathogens of the genus Brucella exhibit marked differences in cell envelope structure, regulation, and biogenesis when compared to more commonly studied gram-negative bacteria and therefore provide an excellent comparative model for study of the gram-negative envelope. We review distinct features of the Brucella envelope, highlighting a conserved regulatory system that links cell cycle progression to envelope biogenesis and cell division. We further discuss recently discovered structural features of the Brucella envelope that ensure envelope integrity and that facilitate cell survival in the face of host immune stressors.

中文翻译：

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布鲁氏菌细胞包膜

细胞膜是一种多层结构，将细菌细胞的内部与混乱的外部世界隔离开来。共同的特征定义了整个细菌界的包膜，但细胞构建和调节这一关键屏障的分子机制是多种多样的，反映了细菌谱系的进化历史。与更常研究的革兰氏阴性细菌相比，布鲁氏菌属的细胞内病原体在细胞包膜结构、调节和生物发生方面表现出显着差异，因此为革兰氏阴性包膜的研究提供了一个极好的比较模型。我们回顾了布鲁氏菌包膜的独特特征，强调了将细胞周期进程与包膜生物发生和细胞分裂联系起来的保守调节系统。我们进一步讨论了最近发现的布鲁氏菌包膜的结构特征，这些特征确保包膜完整性并促进细胞在面对宿主免疫应激源时存活。