Microbial Genetics Laboratory, Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati 517507, Andhra Pradesh, India.
Department of Cosmeceutics, College of Pharmacy, China Medical University, Taichung 40402, Taiwan (Republic of China).
Can J Microbiol. 2021 Apr;67(4):323-331. doi: 10.1139/cjm-2020-0434. Epub 2020 Nov 2.
The enormous spread of infections through biofilms is a major concern in hospital-acquired infections. Biofilm formation by on any surface is facilitated by adjusting its redox status. This organism is a facultative anaerobe shift more towards reductive conditions by enhancing nitrogen metabolism where glutamine synthesis plays a key role. Glutamine is synthesized by glutamine synthetase (GS) encoded by the gene. The gene was amplified by PCR from the chromosomal DNA of , sequenced (HQ329146.1), and cloned. The pure recombinant GS exhibited of 11.06 ± 0.05 mmol·L for glutamate and 2.4 ± 0.03 mmol·L for ATP. The gene sequence showed a high degree of variability with its human counterpart, while it was highly conserved in bacteria. Structural analysis revealed that the GS structure of showed close homology with other Gram-positive bacteria and exhibited a high degree of variation with GS. In the present study, we observed the increased presence of GS activity in multidrug-resistant strains of with elevated biofilm units, grown in brain heart infusion broth; among them methicillin-resistant strains LMV 3, 4, and 5 showed higher biofilm units. All these results explain the important role of glutamine biosynthesis with elevated biofilm units in the pathogenesis of .
生物膜中 感染的广泛传播是医院获得性感染的主要关注点。通过调整其氧化还原状态, 很容易在任何表面形成生物膜。这种生物体是一种兼性厌氧菌,通过增强氮代谢向还原性条件转变,其中谷氨酰胺合成起着关键作用。谷氨酰胺由谷氨酰胺合成酶(GS)合成,该基因由 基因编码。该基因通过从 的染色体 DNA 中扩增 PCR、测序(HQ329146.1)和克隆得到。纯重组 GS 对谷氨酸的 Km 值为 11.06±0.05mmol·L,对 ATP 的 Km 值为 2.4±0.03mmol·L。基因序列显示与人类对应物具有高度的变异性,而在细菌中则高度保守。结构分析表明, 的 GS 结构与其他革兰氏阳性菌具有密切的同源性,并与 GS 具有高度的变异性。在本研究中,我们观察到在脑心浸液肉汤中生长的耐多药 菌株中 GS 活性增加,生物膜单位升高;其中耐甲氧西林菌株 LMV 3、4 和 5 显示出更高的生物膜单位。所有这些结果都解释了谷氨酰胺生物合成在 发病机制中的重要作用,以及生物膜单位升高。