...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>International journal of medical microbiology: IJMM >Bacteria's different ways to recycle their own cell wall
【24h】

Bacteria's different ways to recycle their own cell wall

机译：细菌的不同方式回收自己的细胞壁

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The ability to recover components of their own cell wall is a common feature of bacteria. This was initially recognized in the Gram-negative bacterium Escherichia coli, which recycles about half of the peptidoglycan of its cell wall during one cell doubling. Moreover, E. coli was shown to grow on peptidoglycan components provided as nutrients. A distinguished recycling enzyme of E. coli required for both, recovery of the cell wall sugar N-acetylmuramic acid (MurNAc) of the own cell wall and for growth on external MurNAc, is the MurNAc 6-phosphate (MurNAc 6P) lactyl ether hydrolase MurQ. We revealed however, that most Gram-negative bacteria lack a murQ ortholog and instead harbor a pathway, absent in E. coli, that channels MurNAc directly to peptidoglycan biosynthesis. This "anabolic recycling pathway" bypasses the initial steps of peptidoglycan de novo synthesis, including the target of the antibiotic fosfomycin, thus providing intrinsic resistance to the antibiotic. The Gram-negative oral pathogen Tannerella forsythia is auxotrophic for MurNAc and apparently depends on the anabolic recycling pathway to synthesize its own cell wall by scavenging cell wall debris of other bacteria. In contrast, Gram-positive bacteria lack the anabolic recycling genes, but mostly contain one or two murQ orthologs. Quantification of MurNAc 6P accumulation in murQ mutant cells by mass spectrometry allowed us to demonstrate for the first time that Gram-positive bacteria do recycle their own peptidoglycan. This had been questioned earlier, since peptidoglycan turnover products accumulate in the spent media of Gram-positives. We showed, that these fragments are recovered during nutrient limitation, which prolongs starvation survival of Bacillus subtilis and Staphylococcus aureus. Peptidoglycan recycling in these bacteria however differs, as the cell wall is either cleaved exhaustively and monosaccharide building blocks are taken up (B. subtilis) or disaccharides are released and recycled involving a novel phosphomuramidase (MupG; S.aureus). In B. subtilis also the teichoic acids, covalently bound to the peptidoglycan (wall teichoic acids; WTAs), are recycled. During phosphate limitation, the sn-glycerol-3-phosphate phosphodiesterase GlpQ specifically degrades WTAs of B. subtilis. In S. aureus, in contrast, GlpQ is used to scavenge external teichoic acid sources. Thus, although bacteria generally recover their own cell wall, they apparently apply distinct strategies for breakdown and reutilization of cell wall fragments.
机译：恢复自己的细胞壁组分的能力是细菌的常见特征。这最初在革兰氏阴性细菌大肠杆菌中识别，其在一个细胞加倍期间回收其细胞壁的肽聚糖的约一半。此外，显示大肠杆菌在作为营养成分提供的肽聚糖组分上生长。所需的含有大肠杆菌的差异循环酶，其恢复自身细胞壁的细胞壁糖N-乙酰常规酸（Murnac）和外部Murnac的生长，是Murnac 6-磷酸（Murnac 6P）酸叔丁基醚水解酶默克。然而，我们揭示了，大多数革兰氏阴性细菌缺乏Murq Ortholog，而不是在大肠杆菌中缺席的途径，将Murnac直接与肽聚糖生物合成。这种“代谢再循环途径”绕过肽聚糖的初始步骤，包括抗生素杂霉素的靶标，从而为抗生素提供了内在抗性。革兰阴性口服病原体坦宁菌是营养营养营养素的营养营养素，显然取决于合成代谢再循环途径，通过清除其他细菌的细胞壁碎屑来合成自己的细胞壁。相比之下，革兰氏阳性细菌缺乏合成代谢的回收基因，但大多含有一个或两个Murq Orthologs。 Murq突变细胞的Murnac 6P积聚通过质谱法使我们首次证明革兰氏阳性细菌再循环其自己的肽聚糖。这早些时候受到质疑，因为肽聚糖营业额产物积聚在革兰氏阳性的培养基中。我们表明，这些片段在营养限制期间恢复，延长枯草芽孢杆菌和金黄色葡萄球菌的饥饿存活。然而，在这些细菌中回收的肽聚糖与细胞壁不同，随着细胞壁被详细裂解，并且释放单糖构件（B.枯草芽孢杆菌）或二糖被释放并再循环涉及新的磷酰胺酶（MUPG; S.aureus）。在B.枯草芽孢杆菌中，噻吩酸，与肽聚糖（壁噻吩甲酸; WTA）共价结合，被再循环。在磷酸盐限制期间，Sn-甘油-3-磷酸二磷酸二酯酶GLPQ特异性降解B.枯草芽孢杆菌的WTA。相比之下，在S.UUREUS中，GLPQ用于清除外部噻吩酸源。因此，虽然细菌通常恢复自己的细胞壁，但它们显然对细胞壁碎片的崩溃和再利用进行了明显的策略。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号