Bacterial proliferation in hosts requires activation of a number of housekeeping pathways, including purine de novo biosynthesis. Although inactivation of purine biosynthesis genes can attenuate virulence, it is uncle...Bacterial proliferation in hosts requires activation of a number of housekeeping pathways, including purine de novo biosynthesis. Although inactivation of purine biosynthesis genes can attenuate virulence, it is unclear which biochemical or virulence factors are associated with the purine biosynthesis pathway in vivo. We report that inactivation of purC, a gene encoding phosphoribosylaminoimidazole-succinocarboxamide synthase, caused complete loss of virulence in Xanthomonas campestris pv. cam- pestris, the causal agent of black rot disease of cruciferous plants. The purC mutant was a purine auxotroph; it could not grow on minimal medium, whereas addition of purine derivatives, such as hypoxanthine or adenine plus guanine, restored growth of the mutant. The purC mutation also significantly enhanced the production of an unknown purine synthesis associated pigment and extracellular polysaccharides by the bacterium. In addition, comparative proteomic analyses of bacteria grown on rich and minimal media revealed that the purC mutation affected the expression levels of diverse proteins involved in purine and pyrimidine synthesis, carbon and energy metabolisms, iron uptake, proteolysis, protein secretion, and signal transduction. These results provided clues to understanding the contributions of purine synthesis to bacterial virulence and interactions with host immune systems.展开更多
Chiralα-substituted 1,3-dihydroisobenzofurans are key scaffolds in a number of bioactive natural products and synthetic pharmaceuticals.However,catalytic asymmetric approaches have been rarely developed.Here,a redox ...Chiralα-substituted 1,3-dihydroisobenzofurans are key scaffolds in a number of bioactive natural products and synthetic pharmaceuticals.However,catalytic asymmetric approaches have been rarely developed.Here,a redox deracemization technology is adopted to address the catalytic asymmetric synthesis.A broad range ofα-aryl substituted 1,3-dihydroisobenzofurans are effectively deracemized in high efficiency with excellent ee.α-Alkynyl substituted ethers were also compatible with the deracemization technology.展开更多
基金supported by the grants from the National Basic Research Program of the Ministry of Science and Technology of China(No.2011CB100700)the National Science Foundation of China(Nos.31100065 and 31070081)the Basic Research of Frontiers of the Chinese Academy of Sciences(No.KSCX2-EW-J-6)
文摘Bacterial proliferation in hosts requires activation of a number of housekeeping pathways, including purine de novo biosynthesis. Although inactivation of purine biosynthesis genes can attenuate virulence, it is unclear which biochemical or virulence factors are associated with the purine biosynthesis pathway in vivo. We report that inactivation of purC, a gene encoding phosphoribosylaminoimidazole-succinocarboxamide synthase, caused complete loss of virulence in Xanthomonas campestris pv. cam- pestris, the causal agent of black rot disease of cruciferous plants. The purC mutant was a purine auxotroph; it could not grow on minimal medium, whereas addition of purine derivatives, such as hypoxanthine or adenine plus guanine, restored growth of the mutant. The purC mutation also significantly enhanced the production of an unknown purine synthesis associated pigment and extracellular polysaccharides by the bacterium. In addition, comparative proteomic analyses of bacteria grown on rich and minimal media revealed that the purC mutation affected the expression levels of diverse proteins involved in purine and pyrimidine synthesis, carbon and energy metabolisms, iron uptake, proteolysis, protein secretion, and signal transduction. These results provided clues to understanding the contributions of purine synthesis to bacterial virulence and interactions with host immune systems.
基金financial supported by the National Natural Science Foundation of China(Nos.21971148)Shenzhen Special Funds(No.JCYJ20190807093805572)。
文摘Chiralα-substituted 1,3-dihydroisobenzofurans are key scaffolds in a number of bioactive natural products and synthetic pharmaceuticals.However,catalytic asymmetric approaches have been rarely developed.Here,a redox deracemization technology is adopted to address the catalytic asymmetric synthesis.A broad range ofα-aryl substituted 1,3-dihydroisobenzofurans are effectively deracemized in high efficiency with excellent ee.α-Alkynyl substituted ethers were also compatible with the deracemization technology.
