Water Activity and microbial Stress: Part A

In this video, I am going to explain different water activity and microbial stress. It explains the coping or adaptive mechanisms of microbes or bacteria in low water activity food. It is important to mention that low water activity could be achieved with the desiccation, i.e. removal of water or adding solutes, i.e. osmotic stress (hyperosmotic stress). First, I am going to explain osmotic readjustment to secure turgor pressure, then attraction of K+, then transient early stage cell divisions, then formation of compatible solutes, then structural changes of cell membrane, then biofilm formation, and then changes in the gene expression which controls most of the metabolic functions of a microbial cell. Contents are going to be divided into 3 parts, i.e. three videos. It is important to watch all three videos to understand the complete mode or adaptive mechanisms of microbes under hyperosmotic stress.