DIVISION OF GROUP-XVI SPIROPLASMAS INTO SUBGROUPS

Some group XVI spiroplasmas, such as strains CC-1 (Spiroplasma cantharicola) and CB-1, are associated with cantharid beetles. Fifteen related but heterogeneous strains have been isolated from mosquitoes, other insects, and a flower in France and the United States. In the present study, these seventeen strains have been compared by deformation and metabolism inhibition serological tests, by one-dimensional protein sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and by determination of the guanine-plus-cytosine content of their DNA. Five of the 17 strains were further compared by DNA-DNA hybridization and by restriction enzyme (EcoRI and HindIII) analysis of their DNA. On the basis of the resulting data, we propose that group XVI be subdivided into three subgroups. Subgroup XVI-I is represented by strain CC-1 (ATCC 43207) from a cantharid beetle in the United States, and strain MQ-6 from a wasp; subgroup XVI-2 is represented by strain CB-1 (ATCC 43208) from a cantharid beetle and two strains from mosquitoes, all in the United States; and subgroup XVI-3 is represented by strain Ar-1357 (ATCC 51126) and contains 11 strains from mosquitoes and 1 strain from a flower, all from the Savoy region of France.