Harish Chander, and Praveen Rishi
Department of Microbiology, Panjab University, Chandigarh - 160 014
Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh -160 012
Microbes are involved in a series of interactions with the hostile and diverse physiological conditions of the host where they may ultimately cause disease(s). Pathogens not only encounter potentially lethal conditions in the natural environment, but resist the host defensive mechanisms as well. The ability of bacteria to sense and respond to unscheduled changes in the environments is crucial to their survival. In order to survive, micro-organisms have to overcome many stresses mounted in the form of availability of nutrients, ions, variation in temperature, acidic conditions (inorganic and organic), changes in osmo-molarity, oxidative stress and relatively anaerobic conditions within the gut. They adapt to these stresses by coordinated expression of a number of genes/proteins, which contribute directly or indirectly to their pathogenicity. Understanding of their behaviour in different environments will enable dissection of more targeted strategies to control their infections. Their response to acidic stress is being reviewed in the present attempt.
Key words: Acid stress, microorganisms, survival strategy.