Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway.
J Bacteriol. 2018 Jul 25;200(16). doi: 10.1128/JB.00794-17. Print 2018 Aug 15.
Species within the genus display significant glycan diversity associated with the -linked protein glycosylation () systems due to phase variation and polymorphic genes and gene content. The aim of this study was to examine in detail the genotype and glycosylation phenotype in meningococcal isolates and the changes occurring during short-term asymptomatic carriage. Paired meningococcal isolates derived from 50 asymptomatic meningococcal carriers, taken about 2 months apart, were analyzed with whole-genome sequencing. The -linked protein glycosylation genes were characterized in detail using the Genome Comparator tool at the https://pubmlst.org/ database. Immunoblotting with glycan-specific antibodies (Abs) was used to investigate the protein glycosylation phenotype. All major locus polymorphisms identified in to date were present in our isolate collection, with the variable presence of and , both in combination with either or We identified significant changes and diversity in the genotype and/or glycan phenotype in 96% of the paired isolates. There was also a high degree of glycan microheterogeneity, in which different variants of glycan structures were found at a given glycoprotein. The main mechanism responsible for the observed differences was phase-variable expression of the involved glycosyltransferases and the -acetyltransferase. To our knowledge, this is the first characterization of the genotype and glycosylation phenotype in a larger strain collection. This report thus provides important insight into glycan diversity in and into the phase variability changes that influence the expressed glycoform repertoire during meningococcal carriage. Bacterial meningitis is a serious global health problem, and one of the major causative organisms is , which is also a common commensal in the upper respiratory tract of healthy humans. In bacteria, numerous loci involved in biosynthesis of surface-exposed antigenic structures that are involved in the interaction between bacteria and host are frequently subjected to homologous recombination and phase variation. These mechanisms are well described in , and phase variation provides the ability to change these structures reversibly in response to the environment. Protein glycosylation systems are becoming widely identified in bacteria, and yet little is known about the mechanisms and evolutionary forces influencing glycan composition during carriage and disease.
属内的物种由于相位变化和多态性基因和基因组成显示出与 - 连接蛋白糖基化（）系统相关的显著聚糖多样性。本研究的目的是详细研究脑膜炎奈瑟菌分离株中的基因型和糖基化表型，以及在短期无症状携带过程中发生的变化。从 50 名无症状脑膜炎奈瑟菌携带者中采集约 2 个月的配对脑膜炎奈瑟菌分离株，使用全基因组测序进行分析。使用 https://pubmlst.org/数据库中的 Genome Comparator 工具详细描述 - 连接蛋白糖基化基因。使用糖基特异性抗体（Abs）的免疫印迹法来研究蛋白质糖基化表型。到目前为止，在中鉴定的所有主要 位点多态性都存在于我们的分离株集合中，并且存在可变的 和 ，两者都与 或 组合。我们发现 96%的配对分离株中 基因型和/或聚糖表型发生了显著变化和多样性。在给定糖蛋白中还存在高度的聚糖微观异质性，其中发现了聚糖结构的不同变体。负责观察到的差异的主要机制是涉及糖基转移酶和 - 乙酰基转移酶的相位可变表达。据我们所知，这是在更大的菌株集合中对 基因型和糖基化表型的首次表征。因此，本报告提供了对 中聚糖多样性以及影响脑膜炎奈瑟菌携带期间表达糖型谱的相位可变性变化的重要见解。细菌性脑膜炎是一个严重的全球健康问题，其中一个主要病原体是 ，它也是健康人类上呼吸道的常见共生菌。在细菌中，许多参与合成表面暴露的抗原结构的基因座都参与了细菌与宿主之间的相互作用，这些结构经常受到同源重组和相位变化的影响。这些机制在 中得到了很好的描述，相位变化提供了根据环境可逆改变这些结构的能力。蛋白质糖基化系统在细菌中被广泛识别，但对携带和疾病过程中影响聚糖组成的机制和进化力量知之甚少。
