Hu Xiaoqing, Yang Xi, Wu Shuyan, Lu Xuan, Ma Yuan, Tang Ziyi, Wang Xiaoyuan, Huang Xiaodong, Wang Shuiping
State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China.
Biotechnology School, Jiangnan University, Wuxi 214122, China.
Pathogens. 2024 Nov 23;13(12):1035. doi: 10.3390/pathogens13121035.
Gram-negative bacteria possess an asymmetric outer membrane, where the outer leaflet consists of LPSs and the inner leaflet comprises phospholipids. , an opportunistic milk-borne pathogen that causes severe neonatal meningitis and bacteremia, displays diverse lipopolysaccharide (LPS) structures. As a barrier of the bacterial cell, LPSs likely influenced resistance to environment stresses; however, there are no research reports on this aspect, hindering the development of novel bactericidal strategies overcoming the pathogen's resilience. In the present study, therefore, BAA894 and two LPS mutants (Δ and Δ) were employed to investigate its influences. The Δ mutant showed lower resistance to acidic, alkali, oxidative, and osmotic stresses compared to the wild-type strain BAA894, and the Δ mutant exhibited lower desiccation resistance but higher osmotic resistance. To uncover potential reasons for these differences, comparative lipidomics was conducted. The results showed that compared to BAA894, both mutants showed drastic changes in lipid quantity, and many changed lipids were unsaturated. Additionally, eleven lipid classes exhibited significant variation in the relative content. In particular, the polyunsaturated TGs with double bonds at 5, 7, 12, and 14 displayed significant variation between the wild type and two mutants. Our study is the first to reveal that the changes in the LPS structure of resulted in altered lipid profiles and intensities, which may be a critical biochemical basis for bacterial resistance to harsh stresses.
革兰氏阴性菌具有不对称的外膜，其外层由脂多糖（LPS）组成，内层由磷脂组成。[细菌名称未给出]是一种机会性经乳传播的病原体，可引起严重的新生儿脑膜炎和菌血症，它具有多种脂多糖（LPS）结构。作为细菌细胞的一道屏障，脂多糖可能影响对环境压力的抗性；然而，在这方面尚无研究报道，这阻碍了克服该病原体抗性的新型杀菌策略的开发。因此，在本研究中，使用了[细菌名称未给出]BAA894和两个LPS突变体（Δ[具体突变未给出]和Δ[具体突变未给出]）来研究其影响。与野生型菌株BAA894相比，Δ[具体突变未给出]突变体对酸性、碱性、氧化和渗透压力的抗性较低，而Δ[具体突变未给出]突变体表现出较低的干燥抗性但较高的渗透抗性。为了揭示这些差异的潜在原因，进行了比较脂质组学研究。结果表明，与BAA894相比，两个突变体的脂质数量都发生了剧烈变化，许多变化的脂质是不饱和的。此外，11种类别的脂质在相对含量上表现出显著差异。特别是，在5、7、12和14位具有双键的多不饱和甘油三酯在野生型和两个突变体之间表现出显著差异。我们的研究首次揭示，[细菌名称未给出]LPS结构的变化导致了脂质谱和强度的改变，这可能是细菌对恶劣压力抗性的关键生化基础。
