Purine catabolism in Bacillus fastidiosus

The Gram-positive soil bacterium B. fastidiosus requirers uric acid as the carbon and energy source. This species cannot catabolize glucose. When growing in the presence of uric acid half of the total protein of B. fastidiosus is uricase enzyme. When the bacterium grows in the presence of allantoin no uricase is formed. B. fastidiosus therefor must possess an extremely efficient expression of the gene encoding uricase. Moreover uricase gene expression must be subjected to thight catabolite control. We want to isolate and analyze the gene encoding uricase in order to investigate the regulatory components responsible for the high expression and the thight control. We have analyzed the genomic contents of B. fastidiosus and have found that this organism in addition to the chromosome also contains at least three extra chromosomal elements in form of two large and one smaller plasmid. The replication origin from one of the large plasmids were isolated and its nucleotide sequence determined. It appears to be similar to origin from other plasmids isolated from related species such as B. thuringiensis. The future plan is to determine the entire sequence of all the plasmids of this organisms.