Submitted to: International Journal of Systematic and Evolutionary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/2/2001
Publication Date: N/A
Interpretive Summary: Unknown round-spore producing bacteria were previously discovered while studying the classification of the mosquito-killing bacteria named Bacillus sphaericus. Studies were needed to determine their relationship to the insecticidal organisms. Genetic and biochemical studies of two groups showed them to be distinct and therefore merited designation as new species. They were assigned the names Bacillus pycnus and Bacillus neideii. This study provided information for distinguishing the pathogen and non-pathogens.
Technical Abstract: Previous phylogenetic studies revealed that Bacillus sphaericus sensu lato was a composite of seven or more unrelated taxa, one of which was B. sphaericus and another B. fusiformis. The present study assessed the taxonomic positions of two of the remaining groups (groups 6 and 7). DNA relatedness analyses showed that the two groups were distinct from each other, from B. sphaericus, B. fusiformis, B. silvestris and from the other unidentified clades. The genetic distinction of the two groups was supported by differences in their whole cell fatty acid compositions. The two groups share with all other B. sphaericus-like organisms the inability to grow anaerobically, inability to use common hexoses as sources of carbon, and G+C values of 34 to 36 mol%. Unique characteristics of group 6 include the ability to utilize Beta-hydroxybutyrate, the non-requirement for vitamins, and the inability to grow in 5% NaCl. Characteristics peculiar to group 7 include the inability to utilize pyruvate and growth requirement for cystine. These data show that groups 6 and 7 represent two new species for which the names Bacillus pycnus and Bacillus neideii are proposed.