Shafiei Rasoul, Leprince Pierre, Sombolestani Atena Sadat, Thonart Philippe, Delvigne Frank
Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran.
GIGA-Neurosciences, University of Liège, Liège, Belgium.
Front Microbiol. 2019 Mar 26;10:608. doi: 10.3389/fmicb.2019.00608. eCollection 2019.
Acetic acid bacteria are very vulnerable to environmental changes; hence, they should get acclimated to different kinds of stresses when they undergo downstream processing. In the present study, LMG 23690, a thermo-tolerant strain, was acclimated sequentially to different carbon sources including glucose (condition Glc), a mixture of glucose and ethanol (condition EtOH) and a mixture of glucose and acetic acid (condition GlcAA). Then, the effects of acclimation on the cell proteome profiles and some phenotypic characteristics such as growth in culture medium containing ethanol, and tolerance to freeze-drying process were evaluated. Based on the obtained results, despite the cells acclimated to Glc or EtOH conditions, 86% of acclimated cells to GlcAA condition were culturable and resumed growth with a short lag phase in a culture medium containing ethanol and acetic acid. Interestingly, if LMG 23690 had been acclimated to condition GlcAA, 92% of cells exhibited active cellular dehydrogenases, and 59% of cells were culturable after freeze-drying process. Proteome profiles comparison by 2D-DiGE and MS analysis, revealed distinct physiological status between cells exposed to different acclimation treatments, possibly explaining the resulting diversity in phenotypic characteristics. Results of proteome analysis by 2D-DiGE also showed similarities between the differentially expressed proteins of acclimated cells to EtOH condition and the proteome of acclimated cells to GlcAA condition. Most of the differentially regulated proteins are involved in metabolism, folding, sorting, and degradation processes. In conclusion, acclimation under appropriate sub-lethal conditions can be used as a method to improve cell phenotypic characteristics such as viability, growth under certain conditions, and tolerance to downstream processes.
醋酸菌对环境变化非常敏感；因此，在进行下游加工时，它们应适应不同类型的压力。在本研究中，将耐热菌株LMG 23690依次适应不同的碳源，包括葡萄糖（条件Glc）、葡萄糖和乙醇的混合物（条件EtOH）以及葡萄糖和乙酸的混合物（条件GlcAA）。然后，评估了适应对细胞蛋白质组图谱以及一些表型特征的影响，如在含乙醇培养基中的生长情况和对冻干过程的耐受性。根据所得结果，尽管细胞适应了Glc或EtOH条件，但适应GlcAA条件的细胞中有86%可培养，并在含乙醇和乙酸的培养基中经过短暂的滞后期后恢复生长。有趣的是，如果LMG 23690适应了GlcAA条件，92%的细胞表现出活跃的细胞脱氢酶活性，并且在冻干过程后59%的细胞可培养。通过二维差异凝胶电泳（2D-DiGE）和质谱分析对蛋白质组图谱进行比较，揭示了暴露于不同适应处理的细胞之间不同的生理状态，这可能解释了表型特征中产生的多样性。二维差异凝胶电泳的蛋白质组分析结果还显示，适应EtOH条件的细胞和适应GlcAA条件的细胞中差异表达的蛋白质之间存在相似性。大多数差异调节的蛋白质参与代谢、折叠、分选和降解过程。总之，在适当的亚致死条件下进行适应可作为一种改善细胞表型特征的方法，如活力、在特定条件下的生长以及对下游加工的耐受性。
