Genome-Wide Transcriptional Responses to Carbon Starvation in Nongrowing Lactococcus lactis
Genome-Wide Transcriptional Responses to Carbon Starvation in Nongrowing Lactococcus lactis
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DOI：
10.1128/aem.03748-14
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发表时间：
2015-04-01
影响因子：
4.4
通讯作者：
Kleerebezem, Michiel
中科院分区：
文献类型：
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作者：
Ercan, Onur;Wels, Michiel;Kleerebezem, Michiel
本文介绍了非生长，retentostat培养乳酸乳球菌饥饿的转录适应。通过终止培养基供应24 h，将通过延长的retentostat培养获得的近零生长培养物（mu = 0.0001 h（-1））暴露于饥饿状态，然后通过重新开始向retentostat培养物供应培养基，再进行24 h的恢复期。在饥饿期间，培养物的活力在很大程度上得以保留，并且参与转录和翻译机制、细胞分裂和细胞膜能量代谢的基因的表达受到强烈抑制。这些基因的表达在很大程度上恢复后重新开始的培养基供应。饥饿引发了与支链氨基酸、组氨酸、嘌呤和核黄素合成相关的基因表达升高。发现这些生物合成基因的表达在培养基供应重新开始后保持在升高的水平。此外，饥饿诱导了L. lactis KF 147中，并且这些基因的表达升高在随后的恢复期持续，但是我们试图通过实验证明这些细胞中的自然转化失败。挖掘饥饿反应基因集确定了一个保守的顺式作用元件，类似于乳球菌CodY基序的上游区域的基因与转录和翻译机构，嘌呤生物合成，和L. lactis，这表明CodY在观察到的转录组适应非生长细胞中的饥饿中的作用。
This paper describes the transcriptional adaptations of nongrowing, retentostat cultures of Lactococcus lactis to starvation. Near-zero-growth cultures (mu = 0.0001 h(-1)) obtained by extended retentostat cultivation were exposed to starvation by termination of the medium supply for 24 h, followed by a recovery period of another 24 h by reinitiating the medium supply to the retentostat culture. During starvation, the viability of the culture was largely retained, and the expression of genes involved in transcription and translational machineries, cell division, and cell membrane energy metabolism was strongly repressed. Expression of these genes was largely recovered following the reinitiation of the medium supply. Starvation triggered the elevated expression of genes associated with synthesis of branched-chain amino acids, histidine, purine, and riboflavin. The expression of these biosynthesis genes was found to remain at an elevated level after reinitiation of the medium supply. In addition, starvation induced the complete gene set predicted to be involved in natural competence in L. lactis KF147, and the elevated expression of these genes was sustained during the subsequent recovery period, but our attempts to experimentally demonstrate natural transformation in these cells failed. Mining the starvation response gene set identified a conserved cis-acting element that resembles the lactococcal CodY motif in the upstream regions of genes associated with transcription and translational machineries, purine biosynthesis, and natural transformation in L. lactis, suggesting a role for CodY in the observed transcriptome adaptations to starvation in nongrowing cells.