Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan.
Amino Acids. 2012 Jun;42(6):2059-66. doi: 10.1007/s00726-011-0934-y. Epub 2011 May 17.
Mechanisms of recovery from heat injury in Salmonella typhimurium were elucidated. Recovery of the heat-injured S. typhimurium cells in TSB resulted in full recovery after 3 h of incubation at 37°C. The DNA microarray analysis of 30- and 60-min recovering cells resulted in an increase in transcription of 89 and 141 genes, respectively. Among them, 15 genes, with known function, seemed to be somewhat involved in recovery. They encoded proteins involved in branched-chain amino acid (BCAA) transport (livJ, livH), cell envelope integrity (ddg), heat-shock response (cpxP, rrmJ), phage shock protein (pspA), ribosome modulation factor (rmf), virulence (sseB) transcriptional regulation (rpoE, rpoH, rseA, rseB, rseC) and ArcB signal transduction (sixA) and cytoplasmic membrane protein (fxsA). Among them, the effects of BCAA supplementation on recovery from heat injury were studied to confirm the importance of the BCAA transport liv genes during recovery. It was found that supplementation of TSB with 0.1% BCAA resulted in an enhanced recovery of injured cells in comparison to those recovered in TSB without BCAA. Supplementation of BCAA at 0.1% resulted in a cell count increase 4.4-fold greater than that of the control after 1 h incubation. It seems that BCAA promoted the recovery by promoting protein synthesis either directly through their use in translation or indirectly through stimulation of protein synthesis by activation of the Lrp protein.
阐明了鼠伤寒沙门氏菌从热损伤中恢复的机制。在 TSB 中，热损伤的鼠伤寒沙门氏菌细胞在 37°C 下孵育 3 小时后完全恢复。对 30 分钟和 60 分钟恢复细胞的 DNA 微阵列分析导致转录分别增加 89 和 141 个基因。其中，15 个具有已知功能的基因似乎与恢复过程有些关系。它们编码参与支链氨基酸（BCAA）运输的蛋白质（livJ、livH）、细胞包膜完整性（ddg）、热休克反应（cpxP、rrmJ）、噬菌体休克蛋白（pspA）、核糖体调节因子（rmf）、毒力（sseB）转录调节（rpoE、rpoH、rseA、rseB、rseC）和 ArcB 信号转导（sixA）和细胞质膜蛋白（fxsA）。其中，研究了 BCAA 补充对热损伤恢复的影响，以确认 BCAA 运输 liv 基因在恢复过程中的重要性。结果发现，与在不含 BCAA 的 TSB 中恢复的细胞相比，用 0.1% BCAA 补充 TSB 可增强受损细胞的恢复。在 1 小时孵育后，用 0.1% BCAA 补充可使细胞计数增加 4.4 倍，高于对照。似乎 BCAA 通过直接在翻译中使用它们或通过激活 Lrp 蛋白间接刺激蛋白质合成来促进蛋白质合成，从而促进恢复。
