Salas J A, Johnstone K, Ellar D J
Biochem J. 1985 Jul 1;229(1):241-9. doi: 10.1042/bj2290241.
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.
尿酸是唯一能够触发苛求芽孢杆菌孢子萌发的化合物，这一可能性因以下发现而得到加强：脲基乙醇酸、尿素、氯化铵、2,8 - 二羟基嘌呤以及L - 丙氨酸和O - 氨基甲酰 - D - 丝氨酸的组合作为萌发剂均无效。一系列抑制剂可阻止尿酸触发苛求芽孢杆菌的萌发，这些抑制剂也能抑制休眠孢子提取物中的尿酸酶活性。添加尿酸后，萌发过程中的氧气摄取立即开始，这可能是尿酸酶将尿酸氧化的结果。萌发显示出对尿酸浓度的依赖性，其米氏常数（Km）相对较高（4 - 5 mM）。在热激活孢子萌发的最初10分钟内，孢子皮层还原基团的数量没有可检测到的变化，这表明选择性皮层水解不参与苛求芽孢杆菌萌发的触发机制。基于这些结果，提出了一个模型，其中尿酸酶活性的重新启动是触发苛求芽孢杆菌孢子从休眠状态中萌发的机制。
