title: Role of uricase in the triggering of germination of Bacillus fastidiosus spores.
abstract: The likelihood that uric acid was the only compound capable of triggering germination of Bacillus fastidiosus spores was reinforced by the finding that ureidoglycollic acid, urea, NH4Cl, 2,8-dihydroxypurine and a combination of L-alanine and O-carbamoyl-D-serine were ineffective as germinants. Uric acid-triggered germination of B. fastidiosus was prevented by a range of inhibitors that also inhibited uricase activity in dormant spore extracts. O2 uptake during germination started immediately after addition of uric acid, possibly as a consequence of the oxidation of uric acid by the enzyme uricase. Germination showed a dependence on uric acid concentration, with a relatively high Km (4-5 mM). During the first 10 min of germination of heat-activated spores there was no detectable change in the number of spore-cortex reducing groups, indicating that selective cortex hydrolysis is not involved in the trigger mechanism of germination of B. fastidiosus. On the basis of the results, a model is proposed in which re-initiation of uricase activity is the mechanism by which B. fastidiosus spores are triggered to emerge from the dormant state.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000581:Amidohydrolases / Q000378:metabolism; D001407:Bacillus / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D010101:Oxygen Consumption; D010848:Picolinic Acids / Q000378:metabolism; D013171:Spores, Bacterial / Q000187:drug effects / Q000201:enzymology; D014503:Urate Oxidase / Q000378:metabolism*
chemical_list: D010848:Picolinic Acids; D000255:Adenosine Triphosphate; D014503:Urate Oxidase; D000581:Amidohydrolases; C019659:allantoinase; D002118:Calcium; C004860:dipicolinic acid