Murugan Prem Anand, Sahu Muktesh Kumar, Gupta Manish Kumar, Sankar T Sabari, Chandran Sivasurender, Matheshwaran Saravanan
Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India.
Soft and Biological Matter Laboratory, Department of Physics, Indian Institute of Technology, Kanpur, India.
R Soc Open Sci. 2024 Sep 18;11(9):240822. doi: 10.1098/rsos.240822. eCollection 2024 Sep.
Various environmental signals, such as temperature, pH, nutrient levels, salt content and the presence of other microorganisms, can influence biofilm's development and dynamics. However, the innate mechanisms that govern at the molecular and cellular levels remain elusive. Here, we report the impact of physiologically relevant concentrations of NaCl on biofilm formation and the associated differences in an undomesticated natural isolate of . NaCl exposure and its uptake by bacterial cells induced substantial changes in the architecture of pellicle biofilm and an upsurge in the expansion of biofilm colonies on agar surfaces. We have observed the upregulation of genes involved in motility and the downregulation of genes involved in the biosynthesis of extracellular matrix components through the transcription factor suggesting the possible underlying mechanisms. To further support these observations, we have used Δ Δ null mutants, which showed compromised NaCl-induced effects. Our results indicate that NaCl induces a lifestyle shift in from a sessile biofilm state to an independent unicellular motile state. Overall, we present evidence that NaCl can reprogramme gene expression and alter cellular morphology and the state of cells to adapt to motility, which facilitates the expansion of bacterial colonies.
各种环境信号，如温度、pH值、营养水平、盐含量以及其他微生物的存在，都会影响生物膜的形成和动态变化。然而，在分子和细胞水平上起调控作用的内在机制仍不清楚。在此，我们报告了生理相关浓度的NaCl对生物膜形成的影响以及在一种未驯化的天然分离菌株中相关的差异。NaCl的暴露及其被细菌细胞摄取导致了菌膜生物膜结构的显著变化以及琼脂表面生物膜菌落扩张的激增。我们通过转录因子观察到参与运动性的基因上调以及参与细胞外基质成分生物合成的基因下调，这表明了可能的潜在机制。为了进一步支持这些观察结果，我们使用了ΔΔ缺失突变体，其显示出受损的NaCl诱导效应。我们的结果表明，NaCl诱导了从固着生物膜状态到独立单细胞运动状态的生活方式转变。总体而言，我们提供的证据表明，NaCl可以重新编程基因表达，改变细胞形态和细胞状态以适应运动性，这有利于细菌菌落的扩张。
