To investigate a new glycosylation method. Methods In the presence of TMSOTfas catalyst, 1-O-(3, 5-dinitrobenzoyl)-2, 3, 4, 6-tetra-O-benzyl-α-D-glucopyranose 1 reacted with aseries of carboxylic acid, phenols, alcoh...To investigate a new glycosylation method. Methods In the presence of TMSOTfas catalyst, 1-O-(3, 5-dinitrobenzoyl)-2, 3, 4, 6-tetra-O-benzyl-α-D-glucopyranose 1 reacted with aseries of carboxylic acid, phenols, alcohols and saccharides respectively to give the correspondingglycosylation products. The compounds were determined by ~1H NMR and ^(13)C NMR spectra. ResultsThe α-glu-co-pyranosides and related oligosaccharides were prepared in high yields. Conclusion The3, 5-dinitro-benzoyl group was found to be a good leaving group at the anomeric position andO-glucopyranosides and oligosaccharides were stereoselectively synthesized in good yield.展开更多
Among the 14 serovars of Listeria monocytogenes(Lm),serovar 4b strains are the most predominant isolates linked to human listeriosis outbreaks-a phenotype associated with their unique wall teichoic acid(WTA)decorated ...Among the 14 serovars of Listeria monocytogenes(Lm),serovar 4b strains are the most predominant isolates linked to human listeriosis outbreaks-a phenotype associated with their unique wall teichoic acid(WTA)decorated with galactose(Gal)and glucose(Glu).A wealth of knowledge is available for galactosylated-WTA(Gal-WTA)manipulating bacterial homeostasis and virulence,whereas the relationship between glucosylated-WTA(Glu-WTA)and Gal-WTA in listerial physiology and pathogenesis remains unclear.Here,we find that Glu-WTA and Gal-WTA jointly constitute the O-antigen pattern of serovar 4b Lm;however,Glu-WTA specifically serves as the indispensable ligand for listeriophage LP4 adsorption.Moreover,the co-operation between Glu-and Gal-WTA increases biofilm formation and bacterial resistance to cationic antimicrobial peptide(CRAMP).We further demonstrate that Gal-WTA modulates the anchoring of surface proteins,including IspC,Ami,and InlB.Additionally,dual glycosylated WTA interaction with ActA facilitates bacterial intracellular motility and dissemination.Consistently,Glu-WTA significantly enhances bacterial colonization ability in the mesenteric lymph nodes(MLNs),ileum,liver,and brain of mouse,cooperating with Gal-WTA to facilitate Lm dissemination to distant organs and tissues.In conclusion,we reveal the crucial roles of Glu-WTA in synergizing with Gal-WTA to modulate the integrity of the cell wall structure and exacerbate bacterial infection,providing a global understanding of the hypervirulence and pathogenicity of invasive serovar 4b Lm.展开更多
As a ubiquitous reaction, glucosylation controls the bioactivity of cytokinins in plant growth and development. Here we show that genetic manipulation of zeatin-O- glucosylation regulates the formation of important ag...As a ubiquitous reaction, glucosylation controls the bioactivity of cytokinins in plant growth and development. Here we show that genetic manipulation of zeatin-O- glucosylation regulates the formation of important agronomic traits in rice by manipulating the expression of OscZOG1 gene, encoding a putative zeatin O-glucosyltransferase. We found that OscZOG~ was preferentially expressed in shoot and root meristematic tissues and nascent organs. The growth of lateral roots was stimulated in the overexpression lines, but inhibited in RNA interference lines. In shoots, knockdown of OscZOG1 expression by RNA interference significantly im- proved tillering, panicle branching, grain number per panicle and seed size, which are important agronomic traits for grain yield. In contrast, constitutive expression of OscZOG1 leads to negative effects on the formation of the grain-yielding traits with a marked increase in the accumulation levels of cis-zeatin O-glucoside （cZOG） in the transgenic rice plants. In this study,our findings demonstrate the feasibility of improving the critical yield-determinant agronomic traits, including tiller number, panicle branches, total grain number per panicle and grain weight by downregulating the expression level of OscZOG1. Our results suggest that modulating the levels of cytokinin glucosylation can function as a fine-tuning switch in regulating the formation of agronomic traits in rice.展开更多
Three new glucosylated caffeoylquinic acid isomers (1-3), along with six known compounds, have been isolated from an aqueous extract of the flower buds of Lonicera japonica. Structures of the new compounds were determ...Three new glucosylated caffeoylquinic acid isomers (1-3), along with six known compounds, have been isolated from an aqueous extract of the flower buds of Lonicera japonica. Structures of the new compounds were determined by spectroscopic and chemical methods as (-)-4-O-(4-O-beta-D-glucopyranosylcaffeoyl)quinic acid (-)-3-O-(4-O-beta-D-glucopyranosylcaffeoyl)quinic acid (2), and (-)-5-O-(4-O-beta-D-glucopyranosylcaffeoyl)quinic acid (3), respectively. In the preliminary in vitro assays, two known compounds methyl caffeate and 2'-O-methyladenosine showed inhibitory activity against Coxsackie virus B3 with IC50 values of 3.70 mu mol/L and 6.41 mu mol/L and SI values of 7.8 and 12.1, respectively. (C) 2015 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.展开更多
Uridine diphosphate-glucosyltransferases(UGTs)maintain abscisic acid(ABA)homeostasis in Arabidopsis thaliana by converting ABA to abscisic acid-glucose ester(ABA-GE).UGT71C5 plays an important role in the generation o...Uridine diphosphate-glucosyltransferases(UGTs)maintain abscisic acid(ABA)homeostasis in Arabidopsis thaliana by converting ABA to abscisic acid-glucose ester(ABA-GE).UGT71C5 plays an important role in the generation of ABA-GE.Abscisic acid receptors are crucial upstream components of the ABA signaling pathway,but how UGTs and ABA receptors function together to modulate ABA levels is unknown.Here,we demonstrated that the ABA receptors RCAR12/13 and UGT71 C5 maintain ABA homeostasis in Arabidopsis following rehydration under drought stress.Biochemical analyses show that UGT71C5 directly interacted with RCAR8/12/13 in yeast cells,and the interactions between UGT-71C5 and RCAR12/13 were enhanced by ABA treatment.Enzyme activity analysis showed that ABA-GE contents were significantly elevated in the presence of RCAR12 or RCAR13,suggesting that these ABA receptors enhance the activity of UGT71C5.Determination of the content of ABA and ABA-GE in Arabidopsis following rehydration under drought stress revealed that ABA-GE contents were significantly higher in Arabidopsis plants overexpressing RCAR12 and RCAR13 than in nontransformed plants and plants overexpressing RCAR11 following rehydration under drought stress.These observations suggest that RCAR12 and RCAR13 enhance the activity of UGT71C5 to glycosylate excess ABA into ABA-GE following rehydration under drought stress,representing a rapid mechanism for regulating plant growth and development.展开更多
文摘To investigate a new glycosylation method. Methods In the presence of TMSOTfas catalyst, 1-O-(3, 5-dinitrobenzoyl)-2, 3, 4, 6-tetra-O-benzyl-α-D-glucopyranose 1 reacted with aseries of carboxylic acid, phenols, alcohols and saccharides respectively to give the correspondingglycosylation products. The compounds were determined by ~1H NMR and ^(13)C NMR spectra. ResultsThe α-glu-co-pyranosides and related oligosaccharides were prepared in high yields. Conclusion The3, 5-dinitro-benzoyl group was found to be a good leaving group at the anomeric position andO-glucopyranosides and oligosaccharides were stereoselectively synthesized in good yield.
基金supported by the National Natural Science Foundation of China(32161133025 and 32373012)the Key Research and Development Program of Jiangsu(BE2021331)+2 种基金111 Project(D18007)the Priority Academic Development Program of Jiangsu Higher Education Institutions(PAPD),the State-funded Postdoctoral Researchers Program(GZC20241437)the Jiangsu Funding Program for Excellent Postdoctoral Talent(2024ZB641).
文摘Among the 14 serovars of Listeria monocytogenes(Lm),serovar 4b strains are the most predominant isolates linked to human listeriosis outbreaks-a phenotype associated with their unique wall teichoic acid(WTA)decorated with galactose(Gal)and glucose(Glu).A wealth of knowledge is available for galactosylated-WTA(Gal-WTA)manipulating bacterial homeostasis and virulence,whereas the relationship between glucosylated-WTA(Glu-WTA)and Gal-WTA in listerial physiology and pathogenesis remains unclear.Here,we find that Glu-WTA and Gal-WTA jointly constitute the O-antigen pattern of serovar 4b Lm;however,Glu-WTA specifically serves as the indispensable ligand for listeriophage LP4 adsorption.Moreover,the co-operation between Glu-and Gal-WTA increases biofilm formation and bacterial resistance to cationic antimicrobial peptide(CRAMP).We further demonstrate that Gal-WTA modulates the anchoring of surface proteins,including IspC,Ami,and InlB.Additionally,dual glycosylated WTA interaction with ActA facilitates bacterial intracellular motility and dissemination.Consistently,Glu-WTA significantly enhances bacterial colonization ability in the mesenteric lymph nodes(MLNs),ileum,liver,and brain of mouse,cooperating with Gal-WTA to facilitate Lm dissemination to distant organs and tissues.In conclusion,we reveal the crucial roles of Glu-WTA in synergizing with Gal-WTA to modulate the integrity of the cell wall structure and exacerbate bacterial infection,providing a global understanding of the hypervirulence and pathogenicity of invasive serovar 4b Lm.
基金supported in parts by the Ministry of Science and Technology of China(2012CB944802 and 2012AA101103)the National Natural Science Foundation of China(91317305)the Ministry of Agriculture of China(2014ZX08009-003)
文摘As a ubiquitous reaction, glucosylation controls the bioactivity of cytokinins in plant growth and development. Here we show that genetic manipulation of zeatin-O- glucosylation regulates the formation of important agronomic traits in rice by manipulating the expression of OscZOG1 gene, encoding a putative zeatin O-glucosyltransferase. We found that OscZOG~ was preferentially expressed in shoot and root meristematic tissues and nascent organs. The growth of lateral roots was stimulated in the overexpression lines, but inhibited in RNA interference lines. In shoots, knockdown of OscZOG1 expression by RNA interference significantly im- proved tillering, panicle branching, grain number per panicle and seed size, which are important agronomic traits for grain yield. In contrast, constitutive expression of OscZOG1 leads to negative effects on the formation of the grain-yielding traits with a marked increase in the accumulation levels of cis-zeatin O-glucoside （cZOG） in the transgenic rice plants. In this study,our findings demonstrate the feasibility of improving the critical yield-determinant agronomic traits, including tiller number, panicle branches, total grain number per panicle and grain weight by downregulating the expression level of OscZOG1. Our results suggest that modulating the levels of cytokinin glucosylation can function as a fine-tuning switch in regulating the formation of agronomic traits in rice.
基金Financial support from the National Natural Science Foundation of China (NNSFC,Nos.20772156 and 30825044)the Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT,No.IRT1007)the National Science and Technology Project of China (No.2012ZX09301002-002)
文摘Three new glucosylated caffeoylquinic acid isomers (1-3), along with six known compounds, have been isolated from an aqueous extract of the flower buds of Lonicera japonica. Structures of the new compounds were determined by spectroscopic and chemical methods as (-)-4-O-(4-O-beta-D-glucopyranosylcaffeoyl)quinic acid (-)-3-O-(4-O-beta-D-glucopyranosylcaffeoyl)quinic acid (2), and (-)-5-O-(4-O-beta-D-glucopyranosylcaffeoyl)quinic acid (3), respectively. In the preliminary in vitro assays, two known compounds methyl caffeate and 2'-O-methyladenosine showed inhibitory activity against Coxsackie virus B3 with IC50 values of 3.70 mu mol/L and 6.41 mu mol/L and SI values of 7.8 and 12.1, respectively. (C) 2015 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.
基金supported by grants from the National Natural Science Foundation of China(31671455 to Y.Y.)。
文摘Uridine diphosphate-glucosyltransferases(UGTs)maintain abscisic acid(ABA)homeostasis in Arabidopsis thaliana by converting ABA to abscisic acid-glucose ester(ABA-GE).UGT71C5 plays an important role in the generation of ABA-GE.Abscisic acid receptors are crucial upstream components of the ABA signaling pathway,but how UGTs and ABA receptors function together to modulate ABA levels is unknown.Here,we demonstrated that the ABA receptors RCAR12/13 and UGT71 C5 maintain ABA homeostasis in Arabidopsis following rehydration under drought stress.Biochemical analyses show that UGT71C5 directly interacted with RCAR8/12/13 in yeast cells,and the interactions between UGT-71C5 and RCAR12/13 were enhanced by ABA treatment.Enzyme activity analysis showed that ABA-GE contents were significantly elevated in the presence of RCAR12 or RCAR13,suggesting that these ABA receptors enhance the activity of UGT71C5.Determination of the content of ABA and ABA-GE in Arabidopsis following rehydration under drought stress revealed that ABA-GE contents were significantly higher in Arabidopsis plants overexpressing RCAR12 and RCAR13 than in nontransformed plants and plants overexpressing RCAR11 following rehydration under drought stress.These observations suggest that RCAR12 and RCAR13 enhance the activity of UGT71C5 to glycosylate excess ABA into ABA-GE following rehydration under drought stress,representing a rapid mechanism for regulating plant growth and development.
