Background:

Germicidin is a pyranone antibiotic originally excreted by Streptomyces viridochromogenes NRRL B-1551. Germicidin has an inhibitory effect on the germination of its own arthrospores at a concentration as low as 200 pM (40 pg/ml). Higher concentrations of germicidin inhibited porcine Na+/K+-activated ATPase and retarded the germination of the cress Lepidium sativum with an ID50 of 100 μM. Germicidin was the first known autoregulative inhibitor of spore germination in the genus Streptomyces and was isolated from the supernatant of germinated spores, but also from the supernatant of the submerged culture [1].

Germicidins B inhibited germination of S. coelicolor A3(2) spores above 1 μg/ml. The S. coelicolor A3(2) spores collected from a single petri dish (9 cm i.d.) contained 5.4 μg of germicidin A (