All-Russian Research Institute for Food Additives, Branch of V. M. Gorbatov Federal Research Center for Food Systems (RAS), 55 Liteyny Prospekt, Saint Petersburg, 191014, Russia.
Smorodintsev Research Institute of Influenza, 15/17 Ulitsa Professora Popova, Saint Petersburg, 4197022, Russia.
J Microbiol. 2021 Dec;59(12):1104-1111. doi: 10.1007/s12275-021-1214-5. Epub 2021 Oct 26.
An essential part of designing any biotechnological process is examination of the physiological state of producer cells in different phases of cultivation. The main marker of a bacterial cell's state is its fatty acid (FA) profile, reflecting membrane lipid composition. Consideration of FA composition enables assessment of bacterial responses to cultivation conditions and helps biotechnologists understand the most significant factors impacting cellular metabolism. In this work, soil SDS-degrading Pseudomonas helmanticensis was studied at the fatty acid profile level, including analysis of rearrangement between planktonic and aggregated forms. The set of substrates included fat hydrolysates, SDS, and their mixtures with glucose. Such media are useful in bioplastic production since they can help incrementally lower overall costs. Conventional gas chromatography-mass spectrometry was used for FA analysis. Acridine orange-stained aggregates were observed by epifluorescence microscopy. The bacterium was shown to change fatty acid composition in the presence of hydrolyzed fats or SDS. These changes seem to be driven by the depletion of metabolizable substrates in the culture medium. Cell aggregation has also been found to be a defense strategy, particularly with anionic surfactant (SDS) exposure. It was shown that simple fluidity indices (such as saturated/unsaturated FA ratios) do not always sufficiently characterize a cell's physiological state, and morphological examination is essential in cases where complex carbon sources are used.
设计任何生物技术过程的一个重要部分是检查生产者细胞在不同培养阶段的生理状态。细菌细胞状态的主要标志物是其脂肪酸 (FA) 谱，反映了膜脂组成。考虑 FA 组成可以评估细菌对培养条件的反应，并帮助生物技术人员了解影响细胞代谢的最重要因素。在这项工作中，研究了土壤 SDS 降解假单胞菌在脂肪酸谱水平上的特性，包括对浮游和聚集形式之间的重排进行分析。所研究的底物包括脂肪水解物、SDS 及其与葡萄糖的混合物。由于这些培养基有助于逐步降低总成本，因此在生物塑料生产中非常有用。采用常规气相色谱-质谱法进行 FA 分析。通过荧光显微镜观察吖啶橙染色的聚集物。结果表明，在存在水解脂肪或 SDS 的情况下，细菌会改变脂肪酸组成。这些变化似乎是由培养基中可代谢底物的耗尽驱动的。细胞聚集也被发现是一种防御策略，特别是在暴露于阴离子表面活性剂 (SDS) 时。结果表明，简单的流动性指数（例如饱和/不饱和 FA 比）并不总是足以表征细胞的生理状态，并且在使用复杂碳源的情况下，形态学检查是必不可少的。
