Resistance and Structure of Spores of Bacillus subtilis

Spores of Bacillus subtilis NCDO 2130 were produced on five different media and their structure and resistance to chemicals, to heat and to ultraviolet (uv) irradiation compared. Resistance to one chemical was not necessarily related to resistance to another, to uv irradiation or to heat. Spores with the smallest protoplasts and largest cortices were most resistant to heat, while the least resistant were those in which the protoplasts became electron dense after staining and which had the lowest concentrations of calcium and dipicolinic acid.