Institute of Biology, Jan Kochanowski University in Kielce, Kielce, Poland.
Front Cell Infect Microbiol. 2021 Mar 25;11:620010. doi: 10.3389/fcimb.2021.620010. eCollection 2021.
is a pathogenic, Gram-negative, rod-shaped bacterium that causes ascending urinary tract infections. Swarming motility, urease production, biofilm formation, and the properties of its lipopolysaccharide (LPS) are all factors that contribute to the virulence of this bacterium. Uniquely, members of the O18 serogroup elaborate LPS molecules capped with O antigen polymers built of pentasaccharide repeats; these repeats are modified with a phosphocholine (ChoP) moiety attached to the proximal sugar of each O unit. Decoration of the LPS with ChoP is an important surface modification of many pathogenic and commensal bacteria. The presence of ChoP on the bacterial envelope is correlated with pathogenicity, as decoration with ChoP plays a role in bacterial adhesion to mucosal surfaces, resistance to antimicrobial peptides and sensitivity to complement-mediated killing in several species. The genome of O18 is 3.98 Mb in size, containing 3,762 protein-coding sequences and an overall GC content of 38.7%. Annotation performed using the RAST Annotation Server revealed genes associated with choline phosphorylation, uptake and transfer. Moreover, amino acid sequence alignment of the translated gene revealed it to be homologous to LicC from encoding CTP:phosphocholine cytidylyltransferase. Recognized homologs are located in the O antigen gene clusters of species, near the gene encoding the O antigen flippase, which translocates lipid-linked O units across the inner membrane. This study reveals the genes potentially engaged in LPS decoration with ChoP in O18.
是一种致病性的革兰氏阴性杆状细菌，可引起上行性尿路感染。群集运动、脲酶产生、生物膜形成以及其脂多糖（LPS）的特性都是该细菌毒力的因素。独特的是，O18 血清群的成员详述了 LPS 分子，其带有由五糖重复组成的 O 抗原聚合物的帽；这些重复物用附着在每个 O 单元近端糖上的磷酸胆碱（ChoP）部分进行修饰。ChoP 对 LPS 的修饰是许多致病性和共生细菌的重要表面修饰。细菌包膜上 ChoP 的存在与致病性相关，因为 ChoP 的修饰在几种物种的细菌粘附到粘膜表面、对抗菌肽的抗性和对补体介导杀伤的敏感性中起作用。O18 的基因组大小为 3.98 Mb，包含 3762 个蛋白质编码序列，总 GC 含量为 38.7%。使用 RAST 注释服务器进行注释揭示了与胆碱磷酸化、摄取和转移相关的基因。此外，翻译的 基因的氨基酸序列比对表明它与 编码 CTP：磷酸胆碱胞苷转移酶的 LicC 同源。公认的同源物位于 物种的 O 抗原基因簇中，靠近编码 O 抗原翻转酶的 基因，该翻转酶将脂质连接的 O 单位穿过内膜转运。本研究揭示了 O18 中可能参与 LPS 用 ChoP 修饰的基因。
