John Tyndall discovered that intermittent boiling (cycles of heating and cooling) can kill bacterial endospores. This is a result of Choose one: A. eventual depletion of nutrients in the treated medium. B. accelerated degradation of the endospore cortex. C. cellular autolysins that are activated and degrade the endospore cell wall. D. generation of toxic oxygen species that penetrate and kill the endospore. E. endospores germinating into vegetative cells during the cooling phase.

E

Explanation:

Tyndallization involves heating a substance to eitger boiling point or a little above it and holding it there for 15 minutes for several days in succession. After each heating, the resting period will allow spores that have survived to germinate into bacterial cells. Endospore germination would produce growing (vegetative) cells during the cooling phase. And if the solution were to be reheated at this point, these cells will be killed by the next day's heating. At the end, the substance becomes sterile.

Autoclave was found to be a better means, as Tyndallization could allow some bacterial germination after the three days interval