BIOCHEMICAL DIVERSITY WITHIN THE MYCOPLASMA-MYCOIDES CLUSTER

The metabolism of 51 strains within the 'Mycoplasma mycoides cluster' was investigated by measuring oxygen uptake following the addition of organic substrates to washed cell suspensions. There were extensive di fferences between strains in the range of substrates utilized, the rel ative rates of oxidation and the observed saturation constants for sub strates, which ranged from a few mu M to several mM. M. mycoides subsp . capri and M. mycoides subsp. mycoides LC (large colony) strains were diverse and could not be distinguished by substrate utilization patte rns. However, there were consistent differences in the patterns of sub strate utilization between other groups of the M. mycoides cluster, su ggesting that these patterns may be useful in identification. In parti cular, SC (small colony) strains of M. mycoides subsp. mycoides were d istinguished by their inability to oxidize maltose, trehalose and (at low concentrations) mannose and glucosamine. Surprisingly, the type st rain, M. F38, of Mycoplasma capricolum subsp. capripneumoniae and two further isolates differed from all other strains in that they did not oxidize glucose or other sugars. They did, however. oxidize pyruvate, lactate and 2-oxobutyrate at high rates. The marked metabolic differen ces between these strains and M. capricolum subsp. capricolum strains is in contrast to the genetic evidence that was used to support the de signation of the M. F38 group as a subspecies of M. capricolum.