Injured mitochondria in cells of Euglena gracilis after DNA gyrase inhibitors treatment.

Five quinolone (ofloxacin, cinoxacin, enoxacin, ciprofloxacin, oxolinic acid) and one non-quinolone (coumermycin A1) inhibitors of prokaryotic DNA gyrase used in clinical practice for treatment of bacterial infections were experimentally examinated. As model organism the flagellate Euglena gracilis was used. Ultrastructural changes in chloroplasts and mitochondria caused by inhibitors were quantitavely evaluated. Simultaneously in all cases injury and hereditary loss of chloroplasts (bleaching) were observed in the cells. In some samples about 45% of cup-shaped mitochondria cumulated in the cytoplasm. In damaged mitochondria some degenerative signs were seen, but after the last subcultivation on drug-free media the number of injured mitochondria in the bleached cells yielded to the normal value.