Dipartimento di Biologia, Difesa e Biotecnologie Agro-forestali, Università degli Studi della Basilicata, Potenza, Italy.
Int J Food Microbiol. 2012 Apr 2;155(1-2):51-9. doi: 10.1016/j.ijfoodmicro.2012.01.017. Epub 2012 Jan 28.
The growth of Lactobacillus plantarum WCFS1 and of its ΔccpA ery mutant, WCFS1-2, was compared in batch fermentations in a complex medium at controlled pH (6.5) and temperature (30°C) with or without aeration, in order to evaluate the effect of ccpA inactivation and aeration on growth, metabolism and stress resistance. Inactivation of ccpA and, to a lesser extent, aeration, significantly affected growth, expression of proteins related to pyruvate metabolism and stress, and tolerance to heat, oxidative and cold/starvation stresses. The specific growth rate of the mutant was ca. 60% of that of the wild type strain. Inactivation of ccpA and aerobic growth significantly affected yield and production of lactic and acetic acid. Stationary phase cells were more stress tolerant than exponential phase cells with little or no effect of inactivation of ccpA or aeration. On the other hand, for exponential phase cells inactivation of ccpA impaired both heat stress and cold/starvation stress, but increased oxidative stress tolerance. For both strains, aerobically grown cells were more tolerant of stresses. Evidence for entry in a viable but non-culturable status upon prolonged exposure to cold and starvation was found. Preliminary results of a differential proteomic study further confirmed the role of ccpA in the regulation of carbohydrate catabolism and class I stress response genes and allow to gain further insight on the role of this pleiotropic regulator in metabolism and stress. This is the first study in which the impact of aerobic growth on stress tolerance of L. plantarum is evaluated. Although aerobic cultivation in batch fermentations does not improve growth it does improve stress tolerance, and may have significant technological relevance for the preservation of starter and probiotic cultures.
植物乳杆菌 WCFS1 及其ΔccpA ery 突变体 WCFS1-2 的生长在控制 pH（6.5）和温度（30°C）的复杂培养基中进行批式发酵，比较有无通气的情况下，以评估 ccpA 失活和通气对生长、代谢和应激抗性的影响。ccpA 失活和通气在一定程度上显著影响生长、与丙酮酸代谢和应激相关的蛋白质表达以及对热、氧化和冷/饥饿应激的耐受性。突变体的比生长速率约为野生型菌株的 60%。ccpA 失活和需氧生长显著影响乳酸和乙酸的产量和生产。与野生型相比，处于静止期的细胞比指数期细胞更能耐受应激，但 ccpA 失活和通气对其影响较小。另一方面，对于指数期细胞，ccpA 失活削弱了热应激和冷/饥饿应激，但增加了氧化应激的耐受性。对于两种菌株，需氧生长的细胞对应激更耐受。在长时间暴露于寒冷和饥饿时，进入可存活但非可培养状态的证据。差异蛋白质组学研究的初步结果进一步证实了 ccpA 在碳水化合物分解代谢和 I 类应激反应基因调控中的作用，并进一步了解了该多效调节因子在代谢和应激中的作用。这是首次评估好氧生长对植物乳杆菌应激耐受性的影响的研究。虽然好氧培养在分批发酵中不能提高生长，但它确实提高了应激耐受性，对于保存启动子和益生菌培养物具有重要的技术意义。
