Inhibitors of preferentially stimulated deoxyribonucleic acid synthesis in pneumococci.

During experiments with Haemophilus gallinarum, mycoplasma of similar identity, were isolated from the infraorbital sinuses of chickens with coryza. These organisms were unrelated, serologically and by standard biochemical tests, to any other mycoplasma of avian origin. Furthermore, the organisms grew at room temperature in the absence of serum proteins, and were not pathogenic to either chickens or embryonating chicken eggs. Accordingly, the organisms were named Mycoplasma inocuum sp. n. (Adler, Shifrine, and Ortmayer, J. Bacteriol. 82:239, 1961). It was since determined that antisera against Al. laidlawii, prepared in donkeys (provided by the CSIRO-Animal Health Research Laboratory, Victoria, Australia) and in rabbits, agglutinated 3l. inocuutm at a titer of 1:320. The antisera for M. mycoides, M. agalactiae, Al. capri, and several other strains of goat and cattle origin failed to agglutinate an M. inocuum antigen. Antiserum prepared in rabbits against M. inocuum agglutinated JI. laidlawii at a titer of 1:160. Thus, M. inocuum and Al. laidlawii are serologically homologous. Recently, it was demonstrated (CastrejonDiez, Fisher, and Fisher, J. Bacteriol. 86:627, 1963) that these two mycoplasma differ in their glucose metabolism. .l. inocuum can metabolize glucose through the hexose monophosphate shunt, whereas this shunt is absent in Al. laidlawii. In view of the serological identity and metabolic disimilarity of Al. laidlawii and Al. inocuum, our isolate may be considered as M. laidlawii var. inocuum comb. nov.