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 differences between strains in the range of substrates utilized, the relative rates of oxidation and the observed saturation constants for substrates, 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 patterns. However, there were consistent differences in the patterns of substrate utilization between other groups of the M. mycoides cluster, suggesting that these patterns may be useful in identification. In particular, SC (small colony) strains of M. mycoides subsp. mycoides were distinguished by their inability to oxidize maltose, trehalose and (at low concentrations) mannose and glucosamine. Surprisingly, the type strain, 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 differences between these strains and M. capricolum subsp. capricolum strains is in contrast to the genetic evidence that was used to support the designation of the M. F38 group as a subspecies of M. capricolum.