Final answer:
Before a mature endospore is formed, a vegetative bacterial cell undergoes sporulation, forming a septum, forespore, cortex, and protein spore coat until the endospore is released upon the mother cell's disintegration.
Step-by-step explanation:
Before the formation of a mature endospore, a vegetative bacterial cell undergoes a process called sporulation when faced with adverse conditions, such as nutrient depletion. This process starts with the formation of a septum and the development of a DNA forespore. Next, a protective cortex is formed around the forespore along with layers of peptidoglycan and proteins. The forespore gets encased in a protein spore coat and, after the disintegration of the mother cell, it is released as a mature endospore that can withstand extreme conditions.
During endospore staining, a differential technique is used, making the endospores appear as light green structures, distinct from the pink vegetative cells. The process of germination will eventually reactivate the endospores when conditions become favorable again, allowing the bacteria to resume its normal vegetative state and functions such as growth and cell division.