Han Lin-Li, Shao Huan-Huan, Liu Yong-Cheng, Liu Gang, Xie Chao-Ying, Cheng Xiao-Jie, Wang Hai-Yan, Tan Xue-Mei, Feng Hong
Key Laboratory of Bio-resources and Eco-environment, Ministry of Education, Sichuan Key Laboratory of Molecular Biology and Biotechnology, Sichuan University, Chengdu, 610064, Sichuan, People's Republic of China.
College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, People's Republic of China.
BMC Microbiol. 2017 Jul 11;17(1):156. doi: 10.1186/s12866-017-1066-7.
Bacillus pumilus can secret abundant extracellular enzymes, and may be used as a potential host for the industrial production of enzymes. It is necessary to understand the metabolic processes during cellular growth. Here, an RNA-seq based transcriptome analysis was applied to examine B. pumilus BA06 across various growth stages to reveal metabolic changes under two conditions.
Based on the gene expression levels, changes to metabolism pathways that were specific to various growth phases were enriched by KEGG analysis. Upon entry into the transition from the exponential growth phase, striking changes were revealed that included down-regulation of the tricarboxylic acid cycle, oxidative phosphorylation, flagellar assembly, and chemotaxis signaling. In contrast, the expression of stress-responding genes was induced when entering the transition phase, suggesting that the cell may suffer from stress during this growth stage. As expected, up-regulation of sporulation-related genes was continuous during the stationary growth phase, which was consistent with the observed sporulation. However, the expression pattern of the various extracellular proteases was different, suggesting that the regulatory mechanism may be distinct for various proteases. In addition, two protein secretion pathways were enriched with genes responsive to the observed protein secretion in B. pumilus. However, the expression of some genes that encode sporulation-related proteins and extracellular proteases was delayed by the addition of gelatin to the minimal medium.
The transcriptome data depict global alterations in the genome-wide transcriptome across the various growth phases, which will enable an understanding of the physiology and phenotype of B. pumilus through gene expression.
短小芽孢杆菌能够分泌大量胞外酶，可作为工业酶生产的潜在宿主。了解细胞生长过程中的代谢过程很有必要。在此，应用基于RNA测序的转录组分析来检测短小芽孢杆菌BA06在不同生长阶段的情况，以揭示两种条件下的代谢变化。
基于基因表达水平，通过KEGG分析富集了不同生长阶段特有的代谢途径变化。在从指数生长期进入转换期时，发现了显著变化，包括三羧酸循环、氧化磷酸化、鞭毛组装和趋化信号转导的下调。相反，进入转换期时应激反应基因的表达被诱导，表明细胞在此生长阶段可能遭受应激。正如预期的那样，在稳定生长期，芽孢形成相关基因持续上调，这与观察到的芽孢形成一致。然而，各种胞外蛋白酶的表达模式不同，表明不同蛋白酶的调控机制可能不同。此外，两种蛋白质分泌途径富含对短小芽孢杆菌中观察到的蛋白质分泌有反应的基因。然而，在基本培养基中添加明胶会延迟一些编码芽孢形成相关蛋白和胞外蛋白酶的基因的表达。
转录组数据描绘了不同生长阶段全基因组转录组的全局变化，这将有助于通过基因表达了解短小芽孢杆菌的生理学和表型。
