MUTAGENICITY OF 5,6-DIHYDROPENICILLIC ACID (DHPA) IN DROSOPHILA-MELANOGASTER AND BACTERIAL CONVERSION OF PENICILLIC ACID TO DHPA

We studied the mutagenicity of 5,6-dihydropenicillic acid (DHPA) by me ans of the Drosophila wing-spot test. DHPA (10 mg/ g of medium) signif icantly increased the number of small single and twin spots. Since twi n spots were exclusively caused by mitotic crossing-over, the results demonstrated that DHPA can induce chromosome recombination in Drosophi la somatic cells. Penicillic acid (PA) was converted to DHPA by an inc ubation with Agrobacterium radiobactor. The conversion occurred with o ther spoilage bacteria, such as Pseudomonas aeruginosa and P. cepacia. PA was completely converted to DHPA within a 24-h incubation with P. aeruginosa or P. cepacia in medium containing yeast extract. The resul ts suggested that mutagenic DHPA is produced by environmental bacteria when foods ate contaminated by fungi which produce PA.