Bacterial endospores form when the environment is no longer conducive to active cell
metabolism. The soil bacterium Bacillu subtilis, for example, begins the process of sporulation
when one or more nutrients are depleted. The end product is a small, metabolically dormant
structure that can survive almost indefinitely with no detectable metabolism. Spores have
mechanisms prevent accumulation of potentially lethal mutations in their DNA over periods of
dormancy that can exceed 1,000 years. B. subtilis spores are much more resistant than are the
organism's growing cells to heat, UV radiation, and oxidizing agents, all o which promote
mutations. One factor that prevents potential DNA damage in spores is their greatly decreased
water content. How would decreasing the water content affect some types of mutations? A
reduction in endospore water content prevents oxidation of deoxyribose and minimizes DNA
strand breaks. Low water content in endospores decreases the rate of depurination reactions.
Minimal water content in endospores prevents alkylation of DNA bases. Decreased water
content in endospores reduces the formation of pyrimidine dimers, including cyclobutane rings
and 64 photoproducts..
Bacterial endospores form when the environment is no longer conducive.pdf
1. Bacterial endospores form when the environment is no longer conducive to active cell
metabolism. The soil bacterium Bacillu subtilis, for example, begins the process of sporulation
when one or more nutrients are depleted. The end product is a small, metabolically dormant
structure that can survive almost indefinitely with no detectable metabolism. Spores have
mechanisms prevent accumulation of potentially lethal mutations in their DNA over periods of
dormancy that can exceed 1,000 years. B. subtilis spores are much more resistant than are the
organism's growing cells to heat, UV radiation, and oxidizing agents, all o which promote
mutations. One factor that prevents potential DNA damage in spores is their greatly decreased
water content. How would decreasing the water content affect some types of mutations? A
reduction in endospore water content prevents oxidation of deoxyribose and minimizes DNA
strand breaks. Low water content in endospores decreases the rate of depurination reactions.
Minimal water content in endospores prevents alkylation of DNA bases. Decreased water
content in endospores reduces the formation of pyrimidine dimers, including cyclobutane rings
and 64 photoproducts.
