Biotechnology Application and Research Center, Bilecik Şeyh Edebali University, Bilecik, Turkey.
Department of Molecular Biology and Genetics, Institute of Graduate Education, Bilecik Şeyh Edebali University, Bilecik, Turkey.
World J Microbiol Biotechnol. 2024 May 16;40(7):203. doi: 10.1007/s11274-024-04019-6.
The viable but non-culturable (VBNC) state is considered a survival strategy employed by bacteria to endure stressful conditions, allowing them to stay alive. Bacteria in this state remain unnoticed in live cell counts as they cannot proliferate in standard culture media. VBNC cells pose a significant health risk because they retain their virulence and can revive when conditions normalize. Hence, it is crucial to develop fast, reliable, and cost-effective methods to detect bacteria in the VBNC state, particularly in the context of public health, food safety, and microbial control assessments. This research examined the biomolecular changes in Escherichia coli W3110 induced into the VBNC state in artificial seawater under three different stress conditions (temperature, metal, and antibiotic). Initially, confirmation of VBNC cells under various stresses was done using fluorescence microscopy and plate counts. Subsequently, lipid peroxidation was assessed through the TBARS assay, revealing a notable increase in peroxidation end-products in VBNC cells compared to controls. ATR-FTIR spectroscopy and chemomometrics were employed to analyze biomolecular changes, uncovering significant spectral differences in RNA, protein, and nucleic acid concentrations in VBNC cells compared to controls. Notably, RNA levels increased, while protein and nucleic acid amounts decreased. ROC analyses identified the 995 cm RNA band as a consistent marker across all studied stress conditions, suggesting its potential as a robust biomarker for detecting cells induced into the VBNC state under various stressors.
可培养但不可培养（VBNC）状态被认为是细菌用来应对压力条件的一种生存策略，使它们能够存活下来。处于这种状态的细菌在活细胞计数中不会被注意到，因为它们不能在标准培养基中增殖。VBNC 细胞存在重大健康风险，因为它们保留了其毒力，并且在条件正常化时可以复活。因此，开发快速、可靠和具有成本效益的方法来检测 VBNC 状态下的细菌至关重要，特别是在公共卫生、食品安全和微生物控制评估方面。本研究考察了在人工海水中，三种不同应激条件（温度、金属和抗生素）下诱导进入 VBNC 状态的大肠杆菌 W3110 的生物分子变化。首先，使用荧光显微镜和平板计数法对各种应激条件下的 VBNC 细胞进行了确认。随后，通过 TBARS 测定法评估了脂质过氧化作用，结果表明 VBNC 细胞中的过氧化终产物明显增加，与对照相比。ATR-FTIR 光谱和化学计量学被用来分析生物分子变化，揭示了 VBNC 细胞与对照相比在 RNA、蛋白质和核酸浓度方面的显著光谱差异。值得注意的是，RNA 水平增加，而蛋白质和核酸数量减少。ROC 分析确定了 995 cm RNA 带是所有研究应激条件下的一致标志物，表明其作为检测各种应激源诱导进入 VBNC 状态的细胞的强大生物标志物的潜力。
