Chunduru Jayendra, West Thomas P
Department of Chemistry, Texas A&M University-Commerce, Commerce, TX 75429, USA.
Can J Microbiol. 2018 Jun;64(6):432-438. doi: 10.1139/cjm-2018-0015. Epub 2018 Feb 27.
Regulation of pyrimidine biosynthesis by pyrimidines in the emerging, opportunistic human pathogen Pseudomonas monteilii ATCC 700476 was evident. When wild-type cells were grown on succinate in the presence of uracil or orotic acid, the activities of all 5 pyrimidine biosynthetic enzymes were depressed while the activities of 3 of the enzymes decreased in glucose-grown cells supplemented with uracil or orotic acid compared with unsupplemented cells. Pyrimidine limitation of succinate- or glucose-grown pyrimidine auxotrophic cells lacking orotate phosphoribosyltransferase activity resulted in more than a doubling of the pyrimidine biosynthetic enzyme activities relative to their activities in uracil-grown cells. Independent of carbon source, pyrimidine-limited cells of the pyrimidine auxotrophic cells deficient for dihydroorotase activity generally resulted in a slight elevation or depression of the pyrimidine biosynthetic enzyme activities compared with their activities in cells grown under saturating uracil conditions. Aspartate transcarbamoylase activity in P. monteilii was regulated at the enzyme activity level, since the enzyme was strongly inhibited by CTP, UMP, GMP, GDP, ADP, and UTP. In summary, the regulation of pyrimidine biosynthesis in P. monteilii could be used to control its growth or to differentiate it biochemically from other related species of Pseudomonas.
在新出现的机会性人类病原体蒙氏假单胞菌ATCC 700476中，嘧啶对嘧啶生物合成的调节作用明显。当野生型细胞在尿嘧啶或乳清酸存在的情况下以琥珀酸盐为培养基生长时，所有5种嘧啶生物合成酶的活性均受到抑制，而在添加了尿嘧啶或乳清酸的以葡萄糖为培养基生长的细胞中，有3种酶的活性相较于未添加的细胞有所下降。缺乏乳清酸磷酸核糖基转移酶活性的以琥珀酸盐或葡萄糖为培养基生长的嘧啶营养缺陷型细胞，其嘧啶限制导致嘧啶生物合成酶的活性相对于在尿嘧啶培养基中生长的细胞活性增加了一倍多。与碳源无关，缺乏二氢乳清酸酶活性的嘧啶营养缺陷型细胞的嘧啶限制细胞，与在饱和尿嘧啶条件下生长的细胞相比，其嘧啶生物合成酶的活性通常会略有升高或降低。蒙氏假单胞菌中的天冬氨酸转氨甲酰酶活性在酶活性水平上受到调节，因为该酶受到CTP、UMP、GMP、GDP、ADP和UTP的强烈抑制。总之，蒙氏假单胞菌中嘧啶生物合成的调节可用于控制其生长，或在生化方面将其与假单胞菌的其他相关物种区分开来。
