BACKGROUND Fibroblast growth factor(FGF)15/19,which is expressed in and secreted from the distal ileum,can regulate hepatic glucose metabolism in an endocrine manner.The levels of both bile acids(BAs)and FGF15/19 are ...BACKGROUND Fibroblast growth factor(FGF)15/19,which is expressed in and secreted from the distal ileum,can regulate hepatic glucose metabolism in an endocrine manner.The levels of both bile acids(BAs)and FGF15/19 are elevated after bariatric surgery.However,it is unclear whether the increase in FGF15/19 is induced by BAs.Moreover,it remains to be understood whether FGF15/19 elevations contribute to improvements in hepatic glucose metabolism after bariatric surgery.AIM To investigate the mechanism of improvement of hepatic glucose metabolism by elevated BAs after sleeve gastrectomy(SG).METHODS By calculating and comparing the changes of body weight after SG with SHAM group,we examined the weight-loss effect of SG.The oral glucose tolerance test(OGTT)test and area under the curve of OGTT curves were used to assess the anti-diabetic effects of SG.By detecting the glycogen content,expression and activity of glycogen synthase as well as the glucose-6-phosphatase(G6Pase)and phosphoenolpyruvate carboxykinase(Pepck),we evaluated the hepatic glycogen content and gluconeogenesis activity.We examined the levels of total BA(TBA)together with the farnesoid X receptor(FXR)-agonistic BA subspecies in systemic serum and portal vein at week 12 post-surgery.Then the histological expression of ileal FXR and FGF15 and hepatic FGF receptor 4(FGFR4)with its corresponding signal pathways involved in glucose metabolism were detected.RESULTS After surgery,food intake and body weight gain of SG group was decreased compare with the SHAM group.The hepatic glycogen content and glycogen synthase activity was significantly stimulated after SG,while the expression of the key enzyme for hepatic gluconeogenesis:G6Pase and Pepck,were depressed.TBA levels in serum and portal vein were both elevated after SG,the FXR-agonistic BA subspecies:Chenodeoxycholic acid(CDCA),lithocholic acid(LCA)in serum and CDCA,DCA,LCA in portal vein were all higher in SG group than that in SHAM group.Consequently,the ileal expression of FXR and FGF15 were also advanced in SG group.Moreover,the hepatic expression of FGFR4 was stimulated in SG-operated rats.As a result,the activity of its corresponding pathway for glycogen synthesis:FGFR4-Ras-extracellular signal regulated kinase pathway was stimulated,while the corresponding pathway for hepatic gluconeogenesis:FGFR4-cAMP regulatory element-binding protein-peroxisome proliferator-activated receptorγcoactivator-1αpathway was suppressed.CONCLUSION Elevated BAs after SG induced FGF15 expression in distal ileum by activating their receptor FXR.Furthermore,the promoted FGF15 partly mediated the improving effects on hepatic glucose metabolism of SG.展开更多
In this paper, the role of mixed amino acids in nitrate uptake and assimilation was evaluated in leafy radish by using ^15N labeled nitrate. The mixtures of alanine, β-alanine, aspartic acid, asparagines, glutamic ac...In this paper, the role of mixed amino acids in nitrate uptake and assimilation was evaluated in leafy radish by using ^15N labeled nitrate. The mixtures of alanine, β-alanine, aspartic acid, asparagines, glutamic acid, glutamine, and glycine were sprayed to plant leaf two or four times. The activity of the enzymes related to the process of NO3- reduction （nitrate reductase, nitrite reductase and glutamine synthetase） was affected differently depending on the application rate of mixed amino acids. Applying mixed amino acids increased the fresh weight, dry weight, and N yield. The NO3 content was reduced to 24-38%, but no significant differences were observed in amino acids and proteins. In addition, the nitrogen derived from fertilizer and the ^15N-NO3-recovery rate increased to 2-8% and 15-47%, respectively. These results strongly suggest that the positive effect of mixed amino acids on nitrate uptake and assimilation might be attributed to the regulation on NO3- uptake and assimilation, but not to the preference for amino acids as sources of reduced nitrogen.展开更多
The compound 15α-hydroxyl-oleanolic acid was biotransformed from oleanolic acid with Colletotrichum lini AS3.4486,and its structure was characterized by 1H NMR,13C NMR,HR-ESI-MS and single-crystal X-ray diffraction.T...The compound 15α-hydroxyl-oleanolic acid was biotransformed from oleanolic acid with Colletotrichum lini AS3.4486,and its structure was characterized by 1H NMR,13C NMR,HR-ESI-MS and single-crystal X-ray diffraction.The crystal of the title compound belongs to monoclinic,space group R3 with a=34.255（5）,b=34.255（5）,c=6.8671（14）,β=90°,Z=9,V=6978（2）3,Mr=490.70,Dc=1.051 mg/m3,μ=0.069 mm-1,F（000）=2430,R=0.0375 and wR=0.0808.The title compound is stacked into a three-dimensional network through hydrogen bonds.展开更多
Compound-specific stable isotope analysis of individual amino acids(CSIA-AA)has been widely used in ecological and biogeochemical studies.It has been proven to be powerful in tracing the diet sources and trophic inter...Compound-specific stable isotope analysis of individual amino acids(CSIA-AA)has been widely used in ecological and biogeochemical studies.It has been proven to be powerful in tracing the diet sources and trophic interactions.However,assessing the N sources of mesopelagic fishes has been inconclusive because the mesopelagic fishes’unique domain(water depth ranged from 0 to 1000 m)and unresolved nitrogen isotopes of various forms.This study proposes a new method for coupling instruments(ion chromatography and PreconIRMS)and chemical method of oxidation-reduction of amino acids,and also combinedδ15N of AAs withδ13C of fatty acids(FAs)to analyze the trophic interactions of mesopelagic fishes in the South China Sea(SCS).AAs were isolated by ion chromatography with high peak resolution and collected by an automated fraction collector.The chemical method then converted the AAs into N2 O with a robust oxidation yields and suitable molar ratio of NH2 OH to.Finally,theδ15N of AAs at 20 nmol were measured with a reasonable precision(<0.6‰).With this method,this study report the first batch high precisionδ15N of AAs andδ13C of FAs of mesopelagic fishes collected from SCS.Diaphus luetkeni,Chauliodus minimus and Bathygadus antrodes showed similarδ13C values of 20:4 n-6(~-28‰),while Argyropelecus affinis and Stomias had similar values(~-32‰).These results reflect that mesopelagic fishes had complex diet sources.An increase of 4‰inδ15N of glutamic acid(Glu)was found between piscivorous and planktivorous fishes,which might suggest a trophic discrimination factor of mesopelagic fishes in the SCS.This study usedδ13C of 20:4 n-6 to reveal the diet sources of mesopelagic fishes andδ15N of Glu to clarify trophic level between piscivorous and planktivorous fishes.Thus,this combinative method could therefore ultimately be applied in a variety of deep-sea ecosystem.展开更多
目的:建立顶空气相色谱法测定药用辅料15-羟基硬脂酸聚乙二醇酯中的残留杂质环氧乙烷和二氧六环的含量。为15-羟基硬脂酸聚乙二醇酯的质量控制提供参考和依据。方法:参考国内外药典方法,选用色谱柱DB-5(15 m×0.32 mm, 1μm),以5%苯...目的:建立顶空气相色谱法测定药用辅料15-羟基硬脂酸聚乙二醇酯中的残留杂质环氧乙烷和二氧六环的含量。为15-羟基硬脂酸聚乙二醇酯的质量控制提供参考和依据。方法:参考国内外药典方法,选用色谱柱DB-5(15 m×0.32 mm, 1μm),以5%苯基-95%甲基聚硅氧烷为固定液,采用程序升温模式:起始温度为35℃,维持5 min,以每分钟5℃的速率升温至180℃,然后以每分钟30℃的速率升温至250℃,维持5 min。进样口温度为150℃,检测器温度为250℃,顶空平衡温度70℃,平衡时间45 min,分流比为10∶1。按标准加入法计算供试品中环氧乙烷和二氧六环的含量。结果:在该色谱条件下,环氧乙烷和二氧六环分别在0.5~4μg·mL^(-1)和5~40μg·mL^(-1)范围内线性关系良好(r≥0.99);平均回收率均为75%(RSD=5%,n=9)。来自三个厂家的五批次样品均未检测出环氧乙烷,其中一批样品未检出二氧六环,另外四批样品中二氧六环含量均小于0.005%,符合限度要求。结论:该方法适用于15-羟基硬脂酸聚乙二醇酯中环氧乙烷和二氧六环含量测定,为15-羟基硬脂酸聚乙二醇酯的质量控制提供了参考与指导。展开更多
^15N-labelled phenolic polymers were synthesized by reactions of p-benzoquinone and 1,4-diphenol with ^15N-labelled glycine and were studied by using ^15N CP-MAS NMR technique in combination with chemical approaches.R...^15N-labelled phenolic polymers were synthesized by reactions of p-benzoquinone and 1,4-diphenol with ^15N-labelled glycine and were studied by using ^15N CP-MAS NMR technique in combination with chemical approaches.Results showed that the proportion of polymer nitrogen as N-phenyl amino acid N was not as great as expected,only accounting for 5%-15%;and most of N in polymers occurred in the forms of amide,pyrrole-and indole-like nitrogen,aliphatic amines and isonitrile.It seems that great differences existed between synthetic humic acids and soil humic acids in the type and distribution of nitrogen forms.展开更多
基金the National Natural Science Foundation of China, No. 81600617
文摘BACKGROUND Fibroblast growth factor(FGF)15/19,which is expressed in and secreted from the distal ileum,can regulate hepatic glucose metabolism in an endocrine manner.The levels of both bile acids(BAs)and FGF15/19 are elevated after bariatric surgery.However,it is unclear whether the increase in FGF15/19 is induced by BAs.Moreover,it remains to be understood whether FGF15/19 elevations contribute to improvements in hepatic glucose metabolism after bariatric surgery.AIM To investigate the mechanism of improvement of hepatic glucose metabolism by elevated BAs after sleeve gastrectomy(SG).METHODS By calculating and comparing the changes of body weight after SG with SHAM group,we examined the weight-loss effect of SG.The oral glucose tolerance test(OGTT)test and area under the curve of OGTT curves were used to assess the anti-diabetic effects of SG.By detecting the glycogen content,expression and activity of glycogen synthase as well as the glucose-6-phosphatase(G6Pase)and phosphoenolpyruvate carboxykinase(Pepck),we evaluated the hepatic glycogen content and gluconeogenesis activity.We examined the levels of total BA(TBA)together with the farnesoid X receptor(FXR)-agonistic BA subspecies in systemic serum and portal vein at week 12 post-surgery.Then the histological expression of ileal FXR and FGF15 and hepatic FGF receptor 4(FGFR4)with its corresponding signal pathways involved in glucose metabolism were detected.RESULTS After surgery,food intake and body weight gain of SG group was decreased compare with the SHAM group.The hepatic glycogen content and glycogen synthase activity was significantly stimulated after SG,while the expression of the key enzyme for hepatic gluconeogenesis:G6Pase and Pepck,were depressed.TBA levels in serum and portal vein were both elevated after SG,the FXR-agonistic BA subspecies:Chenodeoxycholic acid(CDCA),lithocholic acid(LCA)in serum and CDCA,DCA,LCA in portal vein were all higher in SG group than that in SHAM group.Consequently,the ileal expression of FXR and FGF15 were also advanced in SG group.Moreover,the hepatic expression of FGFR4 was stimulated in SG-operated rats.As a result,the activity of its corresponding pathway for glycogen synthesis:FGFR4-Ras-extracellular signal regulated kinase pathway was stimulated,while the corresponding pathway for hepatic gluconeogenesis:FGFR4-cAMP regulatory element-binding protein-peroxisome proliferator-activated receptorγcoactivator-1αpathway was suppressed.CONCLUSION Elevated BAs after SG induced FGF15 expression in distal ileum by activating their receptor FXR.Furthermore,the promoted FGF15 partly mediated the improving effects on hepatic glucose metabolism of SG.
基金the Science Foundation of Zhejiang Forestry University, China (2006FR011)
文摘In this paper, the role of mixed amino acids in nitrate uptake and assimilation was evaluated in leafy radish by using ^15N labeled nitrate. The mixtures of alanine, β-alanine, aspartic acid, asparagines, glutamic acid, glutamine, and glycine were sprayed to plant leaf two or four times. The activity of the enzymes related to the process of NO3- reduction （nitrate reductase, nitrite reductase and glutamine synthetase） was affected differently depending on the application rate of mixed amino acids. Applying mixed amino acids increased the fresh weight, dry weight, and N yield. The NO3 content was reduced to 24-38%, but no significant differences were observed in amino acids and proteins. In addition, the nitrogen derived from fertilizer and the ^15N-NO3-recovery rate increased to 2-8% and 15-47%, respectively. These results strongly suggest that the positive effect of mixed amino acids on nitrate uptake and assimilation might be attributed to the regulation on NO3- uptake and assimilation, but not to the preference for amino acids as sources of reduced nitrogen.
基金supported by the starting Foundation of Tianjin University of Science and Technology (No. 20070449)the Natural Science Foundation of Tianjin (Nos. 08JCZDJC15200 and 08JCZDJC15300)
文摘The compound 15α-hydroxyl-oleanolic acid was biotransformed from oleanolic acid with Colletotrichum lini AS3.4486,and its structure was characterized by 1H NMR,13C NMR,HR-ESI-MS and single-crystal X-ray diffraction.The crystal of the title compound belongs to monoclinic,space group R3 with a=34.255（5）,b=34.255（5）,c=6.8671（14）,β=90°,Z=9,V=6978（2）3,Mr=490.70,Dc=1.051 mg/m3,μ=0.069 mm-1,F（000）=2430,R=0.0375 and wR=0.0808.The title compound is stacked into a three-dimensional network through hydrogen bonds.
基金The National Basic Research Program(973 Program)of China under contract No.2014CB441502the National Natural Science Foundation of China under contract No.41876074the Cross-research Center Project by QNLM under contract No.JCZX202007。
文摘Compound-specific stable isotope analysis of individual amino acids(CSIA-AA)has been widely used in ecological and biogeochemical studies.It has been proven to be powerful in tracing the diet sources and trophic interactions.However,assessing the N sources of mesopelagic fishes has been inconclusive because the mesopelagic fishes’unique domain(water depth ranged from 0 to 1000 m)and unresolved nitrogen isotopes of various forms.This study proposes a new method for coupling instruments(ion chromatography and PreconIRMS)and chemical method of oxidation-reduction of amino acids,and also combinedδ15N of AAs withδ13C of fatty acids(FAs)to analyze the trophic interactions of mesopelagic fishes in the South China Sea(SCS).AAs were isolated by ion chromatography with high peak resolution and collected by an automated fraction collector.The chemical method then converted the AAs into N2 O with a robust oxidation yields and suitable molar ratio of NH2 OH to.Finally,theδ15N of AAs at 20 nmol were measured with a reasonable precision(<0.6‰).With this method,this study report the first batch high precisionδ15N of AAs andδ13C of FAs of mesopelagic fishes collected from SCS.Diaphus luetkeni,Chauliodus minimus and Bathygadus antrodes showed similarδ13C values of 20:4 n-6(~-28‰),while Argyropelecus affinis and Stomias had similar values(~-32‰).These results reflect that mesopelagic fishes had complex diet sources.An increase of 4‰inδ15N of glutamic acid(Glu)was found between piscivorous and planktivorous fishes,which might suggest a trophic discrimination factor of mesopelagic fishes in the SCS.This study usedδ13C of 20:4 n-6 to reveal the diet sources of mesopelagic fishes andδ15N of Glu to clarify trophic level between piscivorous and planktivorous fishes.Thus,this combinative method could therefore ultimately be applied in a variety of deep-sea ecosystem.
基金Project supported by the National Natural Science Foundation of China.
文摘^15N-labelled phenolic polymers were synthesized by reactions of p-benzoquinone and 1,4-diphenol with ^15N-labelled glycine and were studied by using ^15N CP-MAS NMR technique in combination with chemical approaches.Results showed that the proportion of polymer nitrogen as N-phenyl amino acid N was not as great as expected,only accounting for 5%-15%;and most of N in polymers occurred in the forms of amide,pyrrole-and indole-like nitrogen,aliphatic amines and isonitrile.It seems that great differences existed between synthetic humic acids and soil humic acids in the type and distribution of nitrogen forms.
