GENETIC-HETEROGENEITY AMONG KETO-ACID-PRODUCING STRAINS OF GLUCONOBACTER-OXYDANS

The genomes of four keto-acid-producing Gluconobacter oxydans strains (ATCC9937, IFO3293, IF012258 and DSM2343) were analysed by pulse-field gel electrophoresis (PFGE). PFGE of undigested DNA allowed the detect ion of plasmids in the following strains: ATCC9937 (3 plasmids; 8, 27, 31 kb), IFO3293 (9 kb), DSM12343 (21 kb). The three plasmids in ATCC9 937 showed no homology to each other or to plasmids in the other strai ns. Seventeen restriction enzymes were tested for use in PFGE analysis of the G. oxydans strains and XbaI was chosen for restriction fragmen t analysis of the genomes. Fairly good resolution of restriction fragm ents at all size ranges was achieved by using three different pulse-ti me programs. The genome sizes of the four strains were estimated to be between 2240 kb and 3787 kb. The XbaI restriction patterns of the fou r strains showed no similarities to each other. Ten random cosmid clon es of ATCC9937 were used as hybridization probes against the four stra ins, but, with the exception of one clone, hybridization signals were only observed with ATCC9937 itself. These data show that the four stra ins are not closely related.