Sporulation

Sporulation
The sporulation process begins when nutritional conditions become unfavorable, near depletion of the nitrogen or carbon source (or both) Many environmental bacteria are able to produce stable dormant, or resting, forms as a branch of their life cycle to enhance their survival under adverse conditions. Such dormant forms are called endospores, cysts, or heterocysts (primarily seen in cyanobacteria), depending on the method of spore formation, which differs between groups of bacteria.
Sporulation involves the production of many new structures, enzymes, and metabolites along with the disappearance of many vegetative cell components. These changes represent a true process of differentiation: A series of genes whose products determine the formation and final composition of the spore are activated.
Morphologically, sporulation begins with the formation of an axial filament . The process continues with an infolding of the membrane so as to produce a double membrane structure whose facing surfaces correspond to the cell wall-synthesizing surface of the cell envelope. The growing points move progressively toward the pole of the cell so as to engulf the developing spore.
Germination
The germination process occurs in three stages: activation, initiation, and outgrowth:
Activation
Most endospores cannot germinate immediately after they have formed. But they can germinate after they have rested for several days or are first activated, in a nutritionally rich medium, by one or another agent that damages the spore coat. Among the agents that can overcome spore dormancy are heat, abrasion, acidity, and compounds containing free sulfhydryl groups.

Initiation
Once activated, a spore will initiate germination if the environmental conditions are favorable. Different species have evolved receptors that recognize different effectors as signaling a rich medium: Thus, initiation is triggered by L-alanine in one species and by adenosine in another. Binding of the effector activates an autolysin that rapidly degrades the cortex peptidoglycan. Water is taken up, calcium dipicolinate is released, and a variety of spore constituents are degraded by hydrolytic enzymes.
Outgrowth
Degradation of the cortex and outer layers results in the emergence of a new vegetative cell consisting of the spore protoplast with its surrounding wall. Outgrowth requires a supply of all nutrients essential for cell growth.
Classification of Bacteria
Classification, nomenclature, and identification are the three separate but interrelated areas of taxonomy. Classification can be defined as the arrangement of organisms into taxonomic groups (taxa) on the basis of similarities or relationships. .Nomenclature is naming an organism by international rules according to its characteristics. Identification refers to the practical use of a classification scheme: (1) to isolate and distinguish desirable organisms from undesirable ones; (2) to verify the special properties of a culture in a clinical setting, (3) to isolate and identify the causative agent of a disease.