Stress proteins in biology and medicine: evolution, adaptation and clinical evaluation

I. Stress response: Stress response is a universal phenomenon. The term, “stress”, generally refers to any physical or psychological change that disrupts the organism's balance or homeostasis. Stress activates many systems in the body, however, through a defined mechanism, which starts at the cellular level. All organisms, from bacteria to humans, have evolved mechanisms to deal with significant changes in their external or internal environments, and though the biochemical mechanism behind this remains the same. The bacterial stress response is a global regulatory system, which is required for the effective adaptation to changes in the environment. The stress proteins, which are associated with adaptive cytoprotective process, are highly conserved among and between species. This is true in case of plants too, since plants are exposed to environmental ques, where an environmental adaptation by plants is a normal process. The decision for these adaptive responses is made by an in-built pre-existing protective system. In the early stages of a successful adaptive response, cells comprise enhanced cellular functions, which are similar to the conditions of stress exposure. Thus, it is hard to distinguish between pathologic responses visa-vis an extreme adaptation to an excessive functional demand. Elucidation of biochemical mechanisms responsible for cellular adaptations to stress unravels hidden dimensions of stress response and its evolution through species.