Number of triplets in 16S rRNA gene related with pathogenicity of Bacillusspp. and Clostridium spp.

The relation between the number of some trinucleotides in the sequence of 1 6S rRNA gene and pathogenicity of bacterial species from the genera of Baci llus and Clostridium was revealed. The species of genus Bacillus, which are pathogenic for humans, mammals and insects, have an increased number of AA A and TAT triplets in 16S rRNA gene. Theoretically, these species, B. anthr acis and B. cereus for example, may be detected in the specimen by the high er ratio of AAA plus TAT triplets to the number of GGG triplet. Species of genus Clostridium, which are pathogenic for humans and mammals, have a maxi mum ratio of AAA and TAT triplet numbers. This ratio was higher than 2.6 fo r pathogenic species and lower than 2.2 for saprophytic ones. These theoret ical data may open a new way for detecting pathogenic bacteria through the determination of triplet numbers in the sequences of 16S rRNA or rRNA. Howe ver, the mechanism of evolutionary relation between the number of AAA and T AT triplets in the sequence of 16S rRNA gene and the pathogenicity of bacte rial species is not known. (C) 2000 Academic Press.