International Education and Research Center for Food and Agricultural Immunology, Graduate School of Agricultural Science, Tohoku University, Miyagi, 980-8572, Japan; Laboratory of Animal Functional Morphology, Graduate School of Agricultural Science, Tohoku University, Miyagi, 980-8572, Japan.
International Education and Research Center for Food and Agricultural Immunology, Graduate School of Agricultural Science, Tohoku University, Miyagi, 980-8572, Japan; Laboratory of Animal Microbiology, Graduate School of Agricultural Science, Tohoku University, Miyagi, 980-8572, Japan.
Biochem Biophys Res Commun. 2024 Mar 5;699:149566. doi: 10.1016/j.bbrc.2024.149566. Epub 2024 Jan 23.
There is increasing interest in the antimicrobial activity of mannosylerythritol lipids-B (MEL-B) against Gram-positive bacteria such as Staphylococcus aureus (S. aureus). However, the specific molecules involved in MEL-B's antimicrobial action against S. aureus have not been identified. This study utilized the Nebraska transposon mutant library (NTML), which contains 1920 mutants, each lacking three-quarters of the genes found in S. aureus. The NTML was screened to identify mutants resistant to MEL-B. Four mutants (Accession Number: SAUSA300_0904, SAUSA300_0752, SAUSA300_0387, and SAUSA300_2311) largely unaffected by incubation with MEL-B, indicating MEL-B resistance. Despite the strong binding of MEL-B to these mutants, the four molecules encoded by the deleted genes (yjbI, clpP, pbuX, or brpS) in each mutant were not directly recognized by MEL-B. Given that these molecules are not localized on the outer surface of S. aureus and that the antibacterial activity of MEL-B against S. aureus is facilitated by the effective transfer of two antibacterial fatty acids (caprylic acid and myristoleic acid) to S. aureus via ME, the deletion of each of the four molecules may alter the peptidoglycan structure, potentially inhibiting the effective transfer of these antimicrobial fatty acids into S. aureus.
人们对甘露糖赤藓糖醇脂质 B（MEL-B）对金黄色葡萄球菌（S. aureus）等革兰氏阳性菌的抗菌活性越来越感兴趣。然而，MEL-B 对 S. aureus 的抗菌作用所涉及的特定分子尚未确定。本研究利用包含 1920 个突变体的内布拉斯加转座子突变体文库（NTML），每个突变体缺失三分之二的 S. aureus 基因。对 NTML 进行筛选以鉴定对 MEL-B 具有抗性的突变体。四个突变体（注册号：SAUSA300_0904、SAUSA300_0752、SAUSA300_0387 和 SAUSA300_2311）在与 MEL-B 孵育时基本不受影响，表明对 MEL-B 具有抗性。尽管 MEL-B 与这些突变体强烈结合，但每个突变体中缺失基因（yjbI、clpP、pbuX 或 brpS）编码的四个分子未被 MEL-B 直接识别。鉴于这些分子不在 S. aureus 的外表面定位，并且 MEL-B 对 S. aureus 的抗菌活性通过 ME 有效地将两种抗菌脂肪酸（辛酸和豆蔻油酸）转移到 S. aureus 中，四个分子中的每一个的缺失都可能改变肽聚糖结构，可能抑制这些抗菌脂肪酸有效转移到 S. aureus 中。
