Structure and Function of Bacterial Cells (page 10)
(This chapter has 10 pages)
© Kenneth Todar, PhD
A bacterial structure
sometimes observed as an
inclusion is actually a type of dormant cell called an endospore.
Endospores are formed by a few groups of Bacteria as
structures, but ultimately they are released as free endospores.
endospores are a fascinating type of cell. Endospores exhibit no signs
of life, being described as cryptobiotic. They are highly
to environmental stresses such as high temperature (some endospores can
be boiled for hours and retain their viability), irradiation, strong
disinfectants, etc. They are probably the most durable cell produced in
nature. Although cryptobiotic, they retain viability indefinitely such
that under appropriate environmental conditions, they germinate back
vegetative cells. Endospores are formed by vegetative cells in response
to environmental signals that indicate a limiting factor for vegetative
growth, such as exhaustion of an essential nutrient. They germinate and
become vegetative cells when the environmental stress is relieved.
endospore-formation is a mechanism of survival rather than a mechanism