Joseph Biju, Mertins Sonja, Stoll Regina, Schär Jennifer, Umesha Kanasinakatte Rudrappa, Luo Qin, Müller-Altrock Stefanie, Goebel Werner
Institut für Hygiene und Mikrobiologie, Universität Würzburg, Gebäude E1, 97080 Würzburg, Germany.
J Bacteriol. 2008 Aug;190(15):5412-30. doi: 10.1128/JB.00259-08. Epub 2008 May 23.
Listeria monocytogenes is able to efficiently utilize glycerol as a carbon source. In a defined minimal medium, the growth rate (during balanced growth) in the presence of glycerol is similar to that in the presence of glucose or cellobiose. Comparative transcriptome analyses of L. monocytogenes showed high-level transcriptional upregulation of the genes known to be involved in glycerol uptake and metabolism (glpFK and glpD) in the presence of glycerol (compared to that in the presence of glucose and/or cellobiose). Levels of expression of the genes encoding a second putative glycerol uptake facilitator (GlpF(2)) and a second putative glycerol kinase (GlpK(2)) were less enhanced under these conditions. GlpK(1) but not GlpK(2) was essential for glycerol catabolism in L. monocytogenes under extracellular conditions, while the loss of GlpK(1) affected replication in Caco-2 cells less than did the loss of GlpK(2) and GlpD. Additional genes whose transcription levels were higher in the presence of glycerol than in the presence of glucose and cellobiose included those for two dihydroxyacetone (Dha) kinases and many genes that are under carbon catabolite repression control. Transcriptional downregulation in the presence of glycerol (compared to those in the presence glucose and cellobiose) was observed for several genes and operons that are positively regulated by glucose, including genes involved in glycolysis, N metabolism, and the biosynthesis of branched-chain amino acids. The highest level of transcriptional upregulation was observed for all PrfA-dependent genes during early and late logarithmic growth in glycerol. Under these conditions, a low level of HPr-Ser-P and a high level of HPr-His-P were present in the cells, suggesting that all enzyme IIA (EIIA) (or EIIB) components of the phosphotransferase system (PTS) permeases expressed will be phosphorylated. These and other data suggest that the phosphorylation state of PTS permeases correlates with PrfA activity.
单核细胞增生李斯特菌能够有效地利用甘油作为碳源。在限定的基本培养基中，（在平衡生长期间）甘油存在时的生长速率与葡萄糖或纤维二糖存在时的生长速率相似。对单核细胞增生李斯特菌的比较转录组分析表明，在甘油存在的情况下（与葡萄糖和/或纤维二糖存在时相比），已知参与甘油摄取和代谢的基因（glpFK和glpD）转录上调水平较高。在这些条件下，编码第二种假定的甘油摄取促进剂（GlpF(2)）和第二种假定的甘油激酶（GlpK(2)）的基因表达水平增强程度较低。在细胞外条件下，GlpK(1)而非GlpK(2)对单核细胞增生李斯特菌的甘油分解代谢至关重要，而GlpK(1)的缺失对Caco-2细胞中复制的影响小于GlpK(2)和GlpD的缺失。在甘油存在时转录水平高于葡萄糖和纤维二糖存在时的其他基因包括两种二羟基丙酮（Dha）激酶的基因以及许多受碳分解代谢物阻遏控制的基因。对于几个受葡萄糖正调控的基因和操纵子，在甘油存在时（与葡萄糖和纤维二糖存在时相比）观察到转录下调，包括参与糖酵解、氮代谢和支链氨基酸生物合成的基因。在甘油的对数生长早期和后期，所有PrfA依赖性基因的转录上调水平最高。在这些条件下，细胞中存在低水平的HPr-Ser-P和高水平的HPr-His-P，这表明所表达的磷酸转移酶系统（PTS）通透酶的所有酶IIA（EIIA）（或EIIB）组分将被磷酸化。这些以及其他数据表明，PTS通透酶的磷酸化状态与PrfA活性相关。
