The hexoses glucose, galactose and fructose serve as important dietary energy sources in animals and glucose plays a central role in energy homeostasis within eucaryotic cells. As relatively little is known about patt...The hexoses glucose, galactose and fructose serve as important dietary energy sources in animals and glucose plays a central role in energy homeostasis within eucaryotic cells. As relatively little is known about patterns of hexose transporters expression in birds gastrointestinal tract, the aim of the study was to examine glucose transporters 2 （GLUT-2） and glucose transporters 5 （GLUT-5） expression in stomach and duodenal epithelium of two different species--broilers （Gallus gallus domesticus） and ostriches （Struthio camelus var. domesticus） chicken. Materials from the two parts of gastrointestinal tract were collected from six 7-day-old female broilers and six 7-day-old female ostriches. Specimens were fixed with 10% formalin, embedded into paraffin, cut into 7 lain thick slices, followed by immunohistochemical staining with polyclonal primary antibodies rabbit anti-GLUT-2 and rabbit anti-GLUT-5; the staining was carried out according to the manufacturers guidelines （IHC kit, Abcam, UK）. The investigation showed that the staining for both antibodies was more intensive in the epithelial cells of stomach and duodenum of the 7-day-old broilers. In duodenal epithelium, goblet cells and brush border membranes were stained in both species, however the signal was stronger for GLUT-5 than GLUT-2. Staining for GLUT-2 and GLUT-5 occurred in different parts of gastrointestinal tract of 7-day-old ostriches, but was weaker compared to 7-day-old broilers, which showed that the gastrointestinal tract of 7-day-old female broilers was more developed for transportation ofhexoses than 7-day-old female ostriches.展开更多
Hexoses accumulate to high concentrations （-200 mM） in storage parenchyma cells of tomato fruit. Hexoses are sourced from the fruit apoplasm as hydrolysis products of phloem-imported sucrose. Three hexose transporte...Hexoses accumulate to high concentrations （-200 mM） in storage parenchyma cells of tomato fruit. Hexoses are sourced from the fruit apoplasm as hydrolysis products of phloem-imported sucrose. Three hexose transporters （LeHT1, LeHT2, LeHT3）, expressed in fruit storage parenchyma ceils, may contribute to hexose uptake by these cells. An analysis of their full-length sequences demonstrated that all three transporters belong to the STP subfamily of monosaccharide transporters that localize to plasma membranes. Heterologous expression of LeHT1 （and previously LeHT2, Gear et al., 2000）, but not LeHT3, rescued a hexose transportimpaired yeast mutant when raised on glucose or fructose as the sole carbon source. Biochemically, LeHT1, similarly to LeHT2, exhibited transport properties consistent with a high- affinity glucose/H^＋ symporter. Significantly, LeHT1 and LeHT2 also functioned as low-affinity fructose/H^＋ symporters with apparent Km values commensurate with those of fruit tissues. A substantial reduction （80-90%） in fruit expression levels of all LeHT genes by RNAi-mediated knockdown caused a 55% decrease in fruit hexose accumulation. In contrast, photoassimilate production by source leaves and phloem transport capacity to fruit were unaffected by transporter knockdown. Collectively, these findings demonstrate that LeHTs play key roles in driving accumulation of hexoses into storage parenchyma cells during tomato fruit development.展开更多
Stereoisomeric hexoses are present in almost all biological organisms in the forms of aldoses and ketoses,with diverse physi-ological and pathophysiological functions.Accurate and simultaneous quantification is vital ...Stereoisomeric hexoses are present in almost all biological organisms in the forms of aldoses and ketoses,with diverse physi-ological and pathophysiological functions.Accurate and simultaneous quantification is vital for understanding their functions individually.However,such analysis remains challenging owing to their highly similar behavior in chromatography and mass spectrometry.By combining the pre-column 3-nitrophenylhydrazine derivatization and ultrahigh performance liquid chroma-tography tandem mass spectrometry(UHPLC-MS/MS),here,we developed a method for simultaneous quantification of five important stereoisomeric hexoses including D-glucose,D-galactose,D-mannose,D-fructose and L-sorbose representing both aldoses and ketoses.The method achieved baseline-separation for all these five derivatized hexoses chromatographically and had high sensitivity(LOD,femtomole on column),excellent linearity(R2>0.995)and efficiency with stable-isotope dilution.With this method,we further quantified these hexoses in nine biological matrices including human biofluids(serum,urine and saliva),human cells,human and mouse feces,rat liver tissue,mung-bean seeds and peach pulp.The results provided quantitative data for these hexoses in multiple biological samples and showed significant concentration diversity for these hexoses in different biological samples,which demonstrated the applicability of the method for simultaneous quantification of these hexose phenotypes of biological systems.展开更多
Objective:To investigate the protective role of Cardiospermum halicacabum(C.halicacabum) leaf extract on glycoprotein metabolism in streptozotocin(STZ)-induced diabetic rats.Methods: Diabetes was induced in male albin...Objective:To investigate the protective role of Cardiospermum halicacabum(C.halicacabum) leaf extract on glycoprotein metabolism in streptozotocin(STZ)-induced diabetic rats.Methods: Diabetes was induced in male albino Wistar rats by intraperitonial administration of STZ.The C.halicacabum leaf extract(CHE) was administered orally to normal and STZ-diabetic rats for 45 days.The effects of C.halicacabum leaf extract(CHE) on plasma and tissue glycoproteins (hexose,hexosamine,fucose and sialic acid) were determined.Results:The levels of plasma and tissues glycoproteins containing hexose,hexosamine and fucose were significantly increased in STZ-induced diabetic rats.In addition,the level of sialic acid significantly increased in plasma and liver while decreased in kidney of STZ-induced diabetic rats.After administration of CHE to diabetic rats,the metabolic alteration of glycoprotein reverted towards normal levels. Conclusions:The present study indicates that the CHE possesses a protective effect on abnormal glycoprotein metabolism in addition to its antihyperglycemic activity.展开更多
文摘The hexoses glucose, galactose and fructose serve as important dietary energy sources in animals and glucose plays a central role in energy homeostasis within eucaryotic cells. As relatively little is known about patterns of hexose transporters expression in birds gastrointestinal tract, the aim of the study was to examine glucose transporters 2 （GLUT-2） and glucose transporters 5 （GLUT-5） expression in stomach and duodenal epithelium of two different species--broilers （Gallus gallus domesticus） and ostriches （Struthio camelus var. domesticus） chicken. Materials from the two parts of gastrointestinal tract were collected from six 7-day-old female broilers and six 7-day-old female ostriches. Specimens were fixed with 10% formalin, embedded into paraffin, cut into 7 lain thick slices, followed by immunohistochemical staining with polyclonal primary antibodies rabbit anti-GLUT-2 and rabbit anti-GLUT-5; the staining was carried out according to the manufacturers guidelines （IHC kit, Abcam, UK）. The investigation showed that the staining for both antibodies was more intensive in the epithelial cells of stomach and duodenum of the 7-day-old broilers. In duodenal epithelium, goblet cells and brush border membranes were stained in both species, however the signal was stronger for GLUT-5 than GLUT-2. Staining for GLUT-2 and GLUT-5 occurred in different parts of gastrointestinal tract of 7-day-old ostriches, but was weaker compared to 7-day-old broilers, which showed that the gastrointestinal tract of 7-day-old female broilers was more developed for transportation ofhexoses than 7-day-old female ostriches.
文摘Hexoses accumulate to high concentrations （-200 mM） in storage parenchyma cells of tomato fruit. Hexoses are sourced from the fruit apoplasm as hydrolysis products of phloem-imported sucrose. Three hexose transporters （LeHT1, LeHT2, LeHT3）, expressed in fruit storage parenchyma ceils, may contribute to hexose uptake by these cells. An analysis of their full-length sequences demonstrated that all three transporters belong to the STP subfamily of monosaccharide transporters that localize to plasma membranes. Heterologous expression of LeHT1 （and previously LeHT2, Gear et al., 2000）, but not LeHT3, rescued a hexose transportimpaired yeast mutant when raised on glucose or fructose as the sole carbon source. Biochemically, LeHT1, similarly to LeHT2, exhibited transport properties consistent with a high- affinity glucose/H^＋ symporter. Significantly, LeHT1 and LeHT2 also functioned as low-affinity fructose/H^＋ symporters with apparent Km values commensurate with those of fruit tissues. A substantial reduction （80-90%） in fruit expression levels of all LeHT genes by RNAi-mediated knockdown caused a 55% decrease in fruit hexose accumulation. In contrast, photoassimilate production by source leaves and phloem transport capacity to fruit were unaffected by transporter knockdown. Collectively, these findings demonstrate that LeHTs play key roles in driving accumulation of hexoses into storage parenchyma cells during tomato fruit development.
基金support from the National Key R&D Program of China(2017YFC0906800)Shanghai Municipal Science and Technology Major Project(2017SHZDZX01)the National Natural Science Foundation of China(81590953,31821002 and 21405020).
文摘Stereoisomeric hexoses are present in almost all biological organisms in the forms of aldoses and ketoses,with diverse physi-ological and pathophysiological functions.Accurate and simultaneous quantification is vital for understanding their functions individually.However,such analysis remains challenging owing to their highly similar behavior in chromatography and mass spectrometry.By combining the pre-column 3-nitrophenylhydrazine derivatization and ultrahigh performance liquid chroma-tography tandem mass spectrometry(UHPLC-MS/MS),here,we developed a method for simultaneous quantification of five important stereoisomeric hexoses including D-glucose,D-galactose,D-mannose,D-fructose and L-sorbose representing both aldoses and ketoses.The method achieved baseline-separation for all these five derivatized hexoses chromatographically and had high sensitivity(LOD,femtomole on column),excellent linearity(R2>0.995)and efficiency with stable-isotope dilution.With this method,we further quantified these hexoses in nine biological matrices including human biofluids(serum,urine and saliva),human cells,human and mouse feces,rat liver tissue,mung-bean seeds and peach pulp.The results provided quantitative data for these hexoses in multiple biological samples and showed significant concentration diversity for these hexoses in different biological samples,which demonstrated the applicability of the method for simultaneous quantification of these hexose phenotypes of biological systems.
基金provided from the National Nutrition Policy Chair,King Saud University,Riyadh,Saudi Arabia
文摘Objective:To investigate the protective role of Cardiospermum halicacabum(C.halicacabum) leaf extract on glycoprotein metabolism in streptozotocin(STZ)-induced diabetic rats.Methods: Diabetes was induced in male albino Wistar rats by intraperitonial administration of STZ.The C.halicacabum leaf extract(CHE) was administered orally to normal and STZ-diabetic rats for 45 days.The effects of C.halicacabum leaf extract(CHE) on plasma and tissue glycoproteins (hexose,hexosamine,fucose and sialic acid) were determined.Results:The levels of plasma and tissues glycoproteins containing hexose,hexosamine and fucose were significantly increased in STZ-induced diabetic rats.In addition,the level of sialic acid significantly increased in plasma and liver while decreased in kidney of STZ-induced diabetic rats.After administration of CHE to diabetic rats,the metabolic alteration of glycoprotein reverted towards normal levels. Conclusions:The present study indicates that the CHE possesses a protective effect on abnormal glycoprotein metabolism in addition to its antihyperglycemic activity.
