endospore The resting stage of certain bacteria, formed in response to adverse conditions. The bacterial cell changes into a partially dehydrated core, enclosed in a multilayered protein coat. On return to favourable conditions the spore germinates and reverts to the normal vegetative form of the organism. Endospores can remain viable for long periods, perhaps several thousands of years. There are even reports of successful germination of endospores obtained from the guts of prehistoric bees preserved in amber for 25–40 million years.

endospore (bacterial) A type of resting cell that develops within a vegetative cell under certain conditions. Endospores are extremely resistant to adverse environmental conditions.

endospore A type of bacterial resting cell that develops within a vegetative cell under certain conditions. Endospores are extremely resistant to adverse environmental conditions.

endospore (end-oh-spor) n. the resting stage of certain bacteria, particularly species of the genera Bacillus and Clostridium.