Isaac J H, Holloway B W
J Bacteriol. 1968 Nov;96(5):1732-41. doi: 10.1128/jb.96.5.1732-1741.1968.
The pathway of pyrimidine biosynthesis in Pseudomonas aeruginosa has been shown to be the same as in other bacteria. Twenty-seven mutants requiring uracil for growth were isolated and the mutant lesions were identified. Mutants lacking either dihydroorotic acid dehydrogenase, orotidine monophosphate pyrophosphorylase, orotidine monophosphate decarboxylase, or aspartic transcarbamylase were isolated; none lacking dihydroorotase were found. By using transduction and conjugation, four genes affecting pyrimidine biosynthetic enzymes have been identified and shown to be unlinked to each other. The linkage of pyrB to met-28 and ilv-2 was shown by contransduction. Repression by uracil alone or by broth could not be demonstrated for any enzymes of this pathway, in contrast to the situation in Escherichia coli and Serratia marcescens. In addition, derepression of these enzymes could not be demonstrated. A low level of feedback inhibition of aspartic transcarbamylase was found to occur. It is suggested that the control of such constitutive biosynthetic enzymes in P. aeruginosa may be related to the comprehensive metabolic activities of this organism.
已证明铜绿假单胞菌中嘧啶生物合成途径与其他细菌相同。分离出了27个生长需要尿嘧啶的突变体，并鉴定了突变损伤。分离出了缺乏二氢乳清酸脱氢酶、乳清苷单磷酸焦磷酸化酶、乳清苷单磷酸脱羧酶或天冬氨酸转氨甲酰酶的突变体；未发现缺乏二氢乳清酸酶的突变体。通过转导和接合，已鉴定出四个影响嘧啶生物合成酶的基因，并且显示它们彼此不连锁。通过共转导显示pyrB与met-28和ilv-2连锁。与大肠杆菌和粘质沙雷氏菌的情况相反，未证明该途径的任何酶受单独的尿嘧啶或肉汤的阻遏。此外，未证明这些酶的去阻遏。发现天冬氨酸转氨甲酰酶存在低水平的反馈抑制。有人认为，铜绿假单胞菌中这种组成型生物合成酶的控制可能与该生物体的综合代谢活动有关。
