The nomenclature for compounds that are modified with isotopes is growing every day. Compounds can be modified with isotopes either individually, in a functional group or groups, or completely with all atomic centers ...The nomenclature for compounds that are modified with isotopes is growing every day. Compounds can be modified with isotopes either individually, in a functional group or groups, or completely with all atomic centers of the element. This diversity of isotope-modified compounds increases the range of researches that can be studied using them. Compounds modified with isotopes of carbon-13 or nitrogen-15 can be converted into carbon monoxide, carbon dioxide and molecular nitrogen. Currently, only the average value of carbon-13 or nitrogen-15 isotopes can be determined. However, by directly determining the atomic share of these isotopes in organic compounds modified with isotopes, information about the isotopic centers of the element can be obtained. The atomic fraction of an element is defined as a single carbon or nitrogen isotope-modified center or centers, or all centers that are isotope-modified with that element at the same time. Carbon-13 or nitrogen-15 isotopes’ atomic fraction can be determined molecularly or with fragment ions of different elemental content, or both. This makes the method self-verifying, increasing the accuracy and reliability of the results obtained. Amino acids, such as asparagine, aspartic acid, methionine, and threonine, are essential for the human body. This proposed method of isotopic analysis will increase the possibilities for scientific research using these compounds.展开更多
The present study analyzed expressional changes of excitatory neurotransmitters and inhibitory neurotransmitters in the rat corpus striatum after single-use and combined-use diazepam and Chinese herb moschus. The infl...The present study analyzed expressional changes of excitatory neurotransmitters and inhibitory neurotransmitters in the rat corpus striatum after single-use and combined-use diazepam and Chinese herb moschus. The influence of moschus on the central nervous system was analyzed, in particular whether moschus increased penetration of other drugs into the brain. Reverse-phase high-performance liquid chromatography, which included pre-column derivation with orthophthaladehyde detection, showed varied increased levels of excitatory neurotransmitters, including aspartate and glutamate, and inhibitory neurotransmitters, including glycine and Y-aminobutyric acid, in the corpus striatum after treatment with moschus alone, diazepam alone, or a combination of both. Compared with the diazepam group, aspartate levels significantly decreased at 30 and 60-105 minutes after combined treatment with moschus, while glutamate significantly increased at 45 and 75-105 minutes, glycine levels significantly increased at 105 minutes, and γ-aminobutyric acid increased at 30 and 75-105 minutes. These findings suggested that moschus increased the inhibition effects of diazepam on the brain.展开更多
Global warming causes the exacerbation of rice growing environment, which seriously affects rice growth and reproduction, and finally results in the decrease of rice yield and quality. We investigated the activities o...Global warming causes the exacerbation of rice growing environment, which seriously affects rice growth and reproduction, and finally results in the decrease of rice yield and quality. We investigated the activities of aspartate metabolism enzymes in grains, and the contents of Aspartate-family amino acids and protein components to further understand the effects of high temperature （HT） on rice nutritional quality during rice grain filling. Under HT, the average activities of aspartate aminotransferase （AAT） and aspartokinase （AK） in grains significantly increased, the amino acid contents of aspartate （Asp）, lysine （Lys）, threonine （Thr）, methionine （Met） and isoleucine （lie） and the protein contents of albumin, globulin, prolamin and glutelin also significantly increased. The results indicated that HT enhanced Asp metabolism during rice grain filling and the enhancement of Asp metabolism might play an important role in the increase of Asp-family amino acids and protein components in grains. In case of the partial appraisal of the change of Asp-family amino acids and protein components under HT, we introduced eight indicators （amino acid or protein content, ratio of amino acid or protein, amino acid or protein content per grain and amino acid or protein content per panicle） to estimate the effects of HT. It is suggested that HT during rice grain filling was benefit for the accumulation of Asp-family amino acids and protein components. Combined with the improvement of Asp-family amino acid ratio in grains under HT, it is suggested that HT during grain filling may improve the rice nutritional quality. However, the yields of parts of Asp-family amino acids and protein components were decreased under HT during rice grain filling.展开更多
AIM:To investigate the effect of bile acid on the expression of histidine decarboxylase(HDC),which is a major enzyme involved in histamine production,and gene expression of gastric transcription factors upon cooperati...AIM:To investigate the effect of bile acid on the expression of histidine decarboxylase(HDC),which is a major enzyme involved in histamine production,and gene expression of gastric transcription factors upon cooperative activation.METHODS:HDC expression was examined by immunohistochemistry,reverse transcriptase polymerase chain reaction,and promoter assay in human gastric precancerous tissues,normal stomach tissue,and gastric cancer cell lines.The relationship between gastric precancerous state and HDC expression induced by bile acid was determined.The association between the expression of HDC and various specific transcription factors in gastric cells was also evaluated.MKN45 and AGS human gastric carcinoma cell lines were transfected with farnesoid X receptor(FXR),small heterodimer partner(SHP),and caudal-type homeodomain transcription factor(CDX)1 expression plasmids.The effects of various transcription factors on HDC expression were monitored by luciferase-reporter promoter assay.RESULTS:Histamine production and secretion in the stomach play critical roles in gastric acid secretion and in the pathogenesis of gastric diseases.Here,we show that bile acid increased the expression of HDC,which is a rate-limiting enzyme of the histamine production pathway.FXR was found to be a primary regulatory transcription factor for bile acid-induced HDC expression.In addition,the transcription factors CDX1 and SHP synergistically enhanced bile acid-induced elevation of HDC gene expression.We confirmed similar expression patterns for HDC,CDX1,and SHP in patient tissues.CONCLUSION:HDC production in the stomach is associated with bile acid exposure and its related transcriptional regulation network of FXR,SHP,and CDX1.展开更多
There is growing interest among nutritionists in feeding reduced protein diets to broiler chickens.Although nearly a century of research has been conducted providing biochemical insights on the impact of reduced prote...There is growing interest among nutritionists in feeding reduced protein diets to broiler chickens.Although nearly a century of research has been conducted providing biochemical insights on the impact of reduced protein diets for broilers,practical limitation still exists.The present review was written to provide insights on further reducing dietary protein in broilers.To construct this review,eighty-nine peer reviewed manuscripts in the area of amino acid nutrition in poultry were critiqued.Hence,nutritional research areas of low protein diets,threonine,glycine,valine,isoleucine,leucine,phenylalanine,histidine,and glutamine have been assessed and combined in this text,thus providing concepts into reduced protein diets for broilers.In addition,linkages between the cited work and least cost formation ingredient and nutrient matrix considerations are provided.In conclusion,practical applications in feeding reduced protein diets to broilers are advancing,but more work is warranted.展开更多
A biodegradable gene transfer vector, poly(ethylenimine)-grafted-poly[(aspartic acid)-co-lysine] has been developed by thermal polycondensation of aspartic acid and lysine, and branch poly(ethylenimine) (Mw less than ...A biodegradable gene transfer vector, poly(ethylenimine)-grafted-poly[(aspartic acid)-co-lysine] has been developed by thermal polycondensation of aspartic acid and lysine, and branch poly(ethylenimine) (Mw less than 600) was grafted to the backbone. The polymer was characterized by 1H NMR. It appeared lower cytotoxity compared to poly(ethylenimine) (25KDa), which was quantified by MTT assay. Electrophoresis indicated that the polymer could retardate DNA at N/P ratio 1.2-1.8 (w/w). Transfection efficiency of the complexes was studied in NT2 cell lines. It was 1.5 fold higher than molecular weight PEI (Mw = 25KDa).展开更多
Serine, one of the nonessential amino acids, is of principal interest because of its capability to form magic-number ionic clusters, which provide a remarkable preference for homochirality. With L-aspartic acid as the...Serine, one of the nonessential amino acids, is of principal interest because of its capability to form magic-number ionic clusters, which provide a remarkable preference for homochirality. With L-aspartic acid as the precursor, this study provides experimental evidence for serine formation in weak acidified aqueous solutions in the presence of iron, with exposure to sunlight, which simulates the natural conditions of the prebiotic aqueous environment. The resultant mixture is directly analyzed via desorption electrospray ionization mass spectrometry（ DESI-MS）, without any sample preseparation. The serine monomer is successfully detected as protonated molecules, giving a peak at m/z 106, which is confirmed by the MS/MS fragments. Protonated serine octamer（ m/z 841 ） is also observed with significant abundance in the MS spectra and is confirmed by the MS/MS data, which shows the formation of the serine octamer by a synthesized serine in the resultant mixture. It is also found that the serine octamer yielded equivalent abundance in the DESI mass spectra in a wide pH range（pH = 1-5 ）, and that existence of ferrous salt and sunshine are essential for the conversion of aspartic acid to serine in the acidic water solution.展开更多
A comparative research has been developed for acidity and stability constants of M(Glu)1, M(Asp)2 and M(Ttr)3 complexes, which have been determined by potentiometric pH titration. Depending on metal ion-binding proper...A comparative research has been developed for acidity and stability constants of M(Glu)1, M(Asp)2 and M(Ttr)3 complexes, which have been determined by potentiometric pH titration. Depending on metal ion-binding properties, vital differences in building complex were observed. The present study indicates that in M(Ttr) com-plexes, metal ions are arranged to the carboxyl groups, but in M(Glu) and M(Asp), some metal ions are able to build chelate over amine groups. The results mentioned-above demonstrate that for some M(Glu) and M(Asp) complexes, the stability constants are also largely determined by the affinity of metal ions for amine group. This leads to a kind of selectivity of metal ions, and transfers them through building complexes accompanied with glutamate and aspartate. For heavy metal ions, this building complex helps the absorption and filtration of the blood plasma, and consequently, the excursion of heavy metal ions takes place. This is an important method in micro-dialysis. In this study the different as-pects of stabilization of metal ion complexes regarding to Irving-Williams sequence have been investigated.展开更多
Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when ad...Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in in-vivo experiment. In the studies, the mechanism for the action of ghrelin was also investigated. It was shown that vagotomy completely inhibited the action of ghrelin on the secretion of gastric acid suggesting that vagal nerve is involved in the mechanism for the action of ghrelin on acid secretion. As famotidine did not inhibit ghrelin-in-duced acid secretion in the study by Masuda et al, they concluded that histamine was not involved in the action of ghrelin on acid secretion. However, we have shown that famotidine completely inhibited ghrelin-induced acid secretion and histidine decarboxylase (HDC) mRNA was increased in gastric mucosa by ghrelin injection which is inhibited by vagotomy Our results indicate that histamine is involved in the action of ghrelin on acid secretion. Furthermore synergistic action of gastrin and ghrelin on gastric acid secretion was shown. Although gastrin has important roles in postprandial secretion of gastric acid, ghrelin may be related to acid secretion during fasting period or at night. However, further studies are needed to elucidate the physiological role of ghrelin in acid secretion.展开更多
Five novel ternary complexes of rare earth ions with L-Aspartic acid (Asp) and o-phenanthroline (Phen) were synthesized in ethanol aqueous solution. Their compositions were characterized by elemental analysis, molar c...Five novel ternary complexes of rare earth ions with L-Aspartic acid (Asp) and o-phenanthroline (Phen) were synthesized in ethanol aqueous solution. Their compositions were characterized by elemental analysis, molar conductance, FT-IR, Raman, UV-VIS and TG-DTA. The compositions of the complexes were confirmed to be: RE(Asp)3PhenCl3·3H2O (RE: Ce3+, Pr3+, Nd3+, Sm3+, Er3+). The antibacterial activity test shows that all these complexes exhibit excellent antibacterial ability against Escherichia coli, Staphylococcus aureus and Candida albicans. The antimicrobial spectrum of the complexes are broad.展开更多
Polyaspartic acid(PASP)is suitable for the inhibition of scale deposition from water.To enhance its in- hibition efficiency,PASP was modified by reacting aspartic acid(Asp)with glutamic acid(Glu)to provide Asp-Glu cop...Polyaspartic acid(PASP)is suitable for the inhibition of scale deposition from water.To enhance its in- hibition efficiency,PASP was modified by reacting aspartic acid(Asp)with glutamic acid(Glu)to provide Asp-Glu copolymer under microwave irradiation.The influence of reaction parameters on conversion,molecular weight and inhibition of CaCO3 precipitation was investigated Infra-red.(IR), 1H nuclear magnetic resonance( 1H NMR)and 13C nuclear magnetic resonance( 13C NMR)spectroscopies were used to characterize the copolymer.The results show that copolymerization of aspartic acid and glutamic acid is catalyzed by a small amount of phosphorous acid (H3PO4)in solvent,the product conversion is 98.05%under the following conditions:the molar ratio of glutamic acid to reactant[Glu/(Asp+Glu)]is 0.3 and that of catalyst(Cat)to reactant[Cat/(Glu+Asp)]is 0.05(0.65ml H3PO4),the volume of solvent dimethylformamide is 16ml,the microwave power used is 720W and the reaction for 3 min.The weight average molecular weight of copolymer synthesized under these conditions is 2709 and the inhi- bition rate for CaCO3 is 97.75%.展开更多
The effects of aspartic acid on the crystal growth, morphology of hydroxyapatite(HAP) crystal were investigated, and the inhibition mechanism of aspartic acid on the crystal growth of hydroxyapatite was studied. The r...The effects of aspartic acid on the crystal growth, morphology of hydroxyapatite(HAP) crystal were investigated, and the inhibition mechanism of aspartic acid on the crystal growth of hydroxyapatite was studied. The results show that the crystal growth rate of HAP decreases with the increase of the aspartic acid concentration, and the HAP crystal is thinner significantly compared with that without amino acid, which is mainly due to the (1 010) surface of HAP crystal being inhibited by the aspartic acids. The calculation analysis indicates that the crystal growth mechanism of HAP, following surface diffusion controlled mechanism, is not changed due to the presence of aspartic acid. AFM result shows that the front of terrace on vicinal growth hillocks is pinned, which suggests that the aspartic acid is adsorbed onto the (1 010) surface of HAP and interacts with the Ca2+ ions of HAP surface, so as to block the growth active sites and result in retarding of the growth of HAP crystal.展开更多
Objective: To observe and elucidate the neuroprotective effect of Xingnaojing (XNJ) injection on hippocampal N-methyl-D-aspartic acid (NMDA) receptors of focal cerebral ischemia in rats. Methods: Cerebral ischemia was...Objective: To observe and elucidate the neuroprotective effect of Xingnaojing (XNJ) injection on hippocampal N-methyl-D-aspartic acid (NMDA) receptors of focal cerebral ischemia in rats. Methods: Cerebral ischemia was established by occluding the middle cerebral artery with an intraluminal suture technique in rats. Neurological deficit score, infarct volume and quantity of NMDA receptors were estimated in all groups and compared. Results: After being treated with XNJ, the score decreased in the initial 6 hours and infarct volume decreased in 24 hours. And within 24 hours, the quantity of NMDA receptors obviously decreased compared with the model group (P<0. 01) It indicated that XNJ could ameliorate neurological behavior of middle cerebral artery occlusion rats and down-regulate the expression of hippocampal NMDA receptors. Conclusion: The neuroprotective effect of XNJ on focal cerebral ischemia is possibly related to down-regulating the expression of NMDA receptors in rats.展开更多
文摘The nomenclature for compounds that are modified with isotopes is growing every day. Compounds can be modified with isotopes either individually, in a functional group or groups, or completely with all atomic centers of the element. This diversity of isotope-modified compounds increases the range of researches that can be studied using them. Compounds modified with isotopes of carbon-13 or nitrogen-15 can be converted into carbon monoxide, carbon dioxide and molecular nitrogen. Currently, only the average value of carbon-13 or nitrogen-15 isotopes can be determined. However, by directly determining the atomic share of these isotopes in organic compounds modified with isotopes, information about the isotopic centers of the element can be obtained. The atomic fraction of an element is defined as a single carbon or nitrogen isotope-modified center or centers, or all centers that are isotope-modified with that element at the same time. Carbon-13 or nitrogen-15 isotopes’ atomic fraction can be determined molecularly or with fragment ions of different elemental content, or both. This makes the method self-verifying, increasing the accuracy and reliability of the results obtained. Amino acids, such as asparagine, aspartic acid, methionine, and threonine, are essential for the human body. This proposed method of isotopic analysis will increase the possibilities for scientific research using these compounds.
文摘The present study analyzed expressional changes of excitatory neurotransmitters and inhibitory neurotransmitters in the rat corpus striatum after single-use and combined-use diazepam and Chinese herb moschus. The influence of moschus on the central nervous system was analyzed, in particular whether moschus increased penetration of other drugs into the brain. Reverse-phase high-performance liquid chromatography, which included pre-column derivation with orthophthaladehyde detection, showed varied increased levels of excitatory neurotransmitters, including aspartate and glutamate, and inhibitory neurotransmitters, including glycine and Y-aminobutyric acid, in the corpus striatum after treatment with moschus alone, diazepam alone, or a combination of both. Compared with the diazepam group, aspartate levels significantly decreased at 30 and 60-105 minutes after combined treatment with moschus, while glutamate significantly increased at 45 and 75-105 minutes, glycine levels significantly increased at 105 minutes, and γ-aminobutyric acid increased at 30 and 75-105 minutes. These findings suggested that moschus increased the inhibition effects of diazepam on the brain.
基金financed by the International Technological Cooperation Program of Science and Technology DepartmentSichuan Province+1 种基金China(Grant No.2010HH0015)greatly thank for the State Scholarship Fund financed by China Scholarship Council(Grant No.201206910010)
文摘Global warming causes the exacerbation of rice growing environment, which seriously affects rice growth and reproduction, and finally results in the decrease of rice yield and quality. We investigated the activities of aspartate metabolism enzymes in grains, and the contents of Aspartate-family amino acids and protein components to further understand the effects of high temperature （HT） on rice nutritional quality during rice grain filling. Under HT, the average activities of aspartate aminotransferase （AAT） and aspartokinase （AK） in grains significantly increased, the amino acid contents of aspartate （Asp）, lysine （Lys）, threonine （Thr）, methionine （Met） and isoleucine （lie） and the protein contents of albumin, globulin, prolamin and glutelin also significantly increased. The results indicated that HT enhanced Asp metabolism during rice grain filling and the enhancement of Asp metabolism might play an important role in the increase of Asp-family amino acids and protein components in grains. In case of the partial appraisal of the change of Asp-family amino acids and protein components under HT, we introduced eight indicators （amino acid or protein content, ratio of amino acid or protein, amino acid or protein content per grain and amino acid or protein content per panicle） to estimate the effects of HT. It is suggested that HT during rice grain filling was benefit for the accumulation of Asp-family amino acids and protein components. Combined with the improvement of Asp-family amino acid ratio in grains under HT, it is suggested that HT during grain filling may improve the rice nutritional quality. However, the yields of parts of Asp-family amino acids and protein components were decreased under HT during rice grain filling.
基金Supported by National Research Foundation of Korea grant funded by the Korea government,No.2009-0093193
文摘AIM:To investigate the effect of bile acid on the expression of histidine decarboxylase(HDC),which is a major enzyme involved in histamine production,and gene expression of gastric transcription factors upon cooperative activation.METHODS:HDC expression was examined by immunohistochemistry,reverse transcriptase polymerase chain reaction,and promoter assay in human gastric precancerous tissues,normal stomach tissue,and gastric cancer cell lines.The relationship between gastric precancerous state and HDC expression induced by bile acid was determined.The association between the expression of HDC and various specific transcription factors in gastric cells was also evaluated.MKN45 and AGS human gastric carcinoma cell lines were transfected with farnesoid X receptor(FXR),small heterodimer partner(SHP),and caudal-type homeodomain transcription factor(CDX)1 expression plasmids.The effects of various transcription factors on HDC expression were monitored by luciferase-reporter promoter assay.RESULTS:Histamine production and secretion in the stomach play critical roles in gastric acid secretion and in the pathogenesis of gastric diseases.Here,we show that bile acid increased the expression of HDC,which is a rate-limiting enzyme of the histamine production pathway.FXR was found to be a primary regulatory transcription factor for bile acid-induced HDC expression.In addition,the transcription factors CDX1 and SHP synergistically enhanced bile acid-induced elevation of HDC gene expression.We confirmed similar expression patterns for HDC,CDX1,and SHP in patient tissues.CONCLUSION:HDC production in the stomach is associated with bile acid exposure and its related transcriptional regulation network of FXR,SHP,and CDX1.
文摘There is growing interest among nutritionists in feeding reduced protein diets to broiler chickens.Although nearly a century of research has been conducted providing biochemical insights on the impact of reduced protein diets for broilers,practical limitation still exists.The present review was written to provide insights on further reducing dietary protein in broilers.To construct this review,eighty-nine peer reviewed manuscripts in the area of amino acid nutrition in poultry were critiqued.Hence,nutritional research areas of low protein diets,threonine,glycine,valine,isoleucine,leucine,phenylalanine,histidine,and glutamine have been assessed and combined in this text,thus providing concepts into reduced protein diets for broilers.In addition,linkages between the cited work and least cost formation ingredient and nutrient matrix considerations are provided.In conclusion,practical applications in feeding reduced protein diets to broilers are advancing,but more work is warranted.
文摘A biodegradable gene transfer vector, poly(ethylenimine)-grafted-poly[(aspartic acid)-co-lysine] has been developed by thermal polycondensation of aspartic acid and lysine, and branch poly(ethylenimine) (Mw less than 600) was grafted to the backbone. The polymer was characterized by 1H NMR. It appeared lower cytotoxity compared to poly(ethylenimine) (25KDa), which was quantified by MTT assay. Electrophoresis indicated that the polymer could retardate DNA at N/P ratio 1.2-1.8 (w/w). Transfection efficiency of the complexes was studied in NT2 cell lines. It was 1.5 fold higher than molecular weight PEI (Mw = 25KDa).
基金Supported by the National Natural Science Foundation of China(No.20505003).
文摘Serine, one of the nonessential amino acids, is of principal interest because of its capability to form magic-number ionic clusters, which provide a remarkable preference for homochirality. With L-aspartic acid as the precursor, this study provides experimental evidence for serine formation in weak acidified aqueous solutions in the presence of iron, with exposure to sunlight, which simulates the natural conditions of the prebiotic aqueous environment. The resultant mixture is directly analyzed via desorption electrospray ionization mass spectrometry（ DESI-MS）, without any sample preseparation. The serine monomer is successfully detected as protonated molecules, giving a peak at m/z 106, which is confirmed by the MS/MS fragments. Protonated serine octamer（ m/z 841 ） is also observed with significant abundance in the MS spectra and is confirmed by the MS/MS data, which shows the formation of the serine octamer by a synthesized serine in the resultant mixture. It is also found that the serine octamer yielded equivalent abundance in the DESI mass spectra in a wide pH range（pH = 1-5 ）, and that existence of ferrous salt and sunshine are essential for the conversion of aspartic acid to serine in the acidic water solution.
文摘A comparative research has been developed for acidity and stability constants of M(Glu)1, M(Asp)2 and M(Ttr)3 complexes, which have been determined by potentiometric pH titration. Depending on metal ion-binding properties, vital differences in building complex were observed. The present study indicates that in M(Ttr) com-plexes, metal ions are arranged to the carboxyl groups, but in M(Glu) and M(Asp), some metal ions are able to build chelate over amine groups. The results mentioned-above demonstrate that for some M(Glu) and M(Asp) complexes, the stability constants are also largely determined by the affinity of metal ions for amine group. This leads to a kind of selectivity of metal ions, and transfers them through building complexes accompanied with glutamate and aspartate. For heavy metal ions, this building complex helps the absorption and filtration of the blood plasma, and consequently, the excursion of heavy metal ions takes place. This is an important method in micro-dialysis. In this study the different as-pects of stabilization of metal ion complexes regarding to Irving-Williams sequence have been investigated.
文摘Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in in-vivo experiment. In the studies, the mechanism for the action of ghrelin was also investigated. It was shown that vagotomy completely inhibited the action of ghrelin on the secretion of gastric acid suggesting that vagal nerve is involved in the mechanism for the action of ghrelin on acid secretion. As famotidine did not inhibit ghrelin-in-duced acid secretion in the study by Masuda et al, they concluded that histamine was not involved in the action of ghrelin on acid secretion. However, we have shown that famotidine completely inhibited ghrelin-induced acid secretion and histidine decarboxylase (HDC) mRNA was increased in gastric mucosa by ghrelin injection which is inhibited by vagotomy Our results indicate that histamine is involved in the action of ghrelin on acid secretion. Furthermore synergistic action of gastrin and ghrelin on gastric acid secretion was shown. Although gastrin has important roles in postprandial secretion of gastric acid, ghrelin may be related to acid secretion during fasting period or at night. However, further studies are needed to elucidate the physiological role of ghrelin in acid secretion.
基金Project supported by Shanghai Technology Committee Research Fund (0552nm036)Shanghai Leading Academic Discipline Project (T0402)+1 种基金Shanghai-Unilever Research and Development Fund (200406)Shanghai Education Committee Research Fund (05DZ19)
文摘Five novel ternary complexes of rare earth ions with L-Aspartic acid (Asp) and o-phenanthroline (Phen) were synthesized in ethanol aqueous solution. Their compositions were characterized by elemental analysis, molar conductance, FT-IR, Raman, UV-VIS and TG-DTA. The compositions of the complexes were confirmed to be: RE(Asp)3PhenCl3·3H2O (RE: Ce3+, Pr3+, Nd3+, Sm3+, Er3+). The antibacterial activity test shows that all these complexes exhibit excellent antibacterial ability against Escherichia coli, Staphylococcus aureus and Candida albicans. The antimicrobial spectrum of the complexes are broad.
基金Supported by Harbin Key Technologies R&D Program(No.2003AA4CS123).
文摘Polyaspartic acid(PASP)is suitable for the inhibition of scale deposition from water.To enhance its in- hibition efficiency,PASP was modified by reacting aspartic acid(Asp)with glutamic acid(Glu)to provide Asp-Glu copolymer under microwave irradiation.The influence of reaction parameters on conversion,molecular weight and inhibition of CaCO3 precipitation was investigated Infra-red.(IR), 1H nuclear magnetic resonance( 1H NMR)and 13C nuclear magnetic resonance( 13C NMR)spectroscopies were used to characterize the copolymer.The results show that copolymerization of aspartic acid and glutamic acid is catalyzed by a small amount of phosphorous acid (H3PO4)in solvent,the product conversion is 98.05%under the following conditions:the molar ratio of glutamic acid to reactant[Glu/(Asp+Glu)]is 0.3 and that of catalyst(Cat)to reactant[Cat/(Glu+Asp)]is 0.05(0.65ml H3PO4),the volume of solvent dimethylformamide is 16ml,the microwave power used is 720W and the reaction for 3 min.The weight average molecular weight of copolymer synthesized under these conditions is 2709 and the inhi- bition rate for CaCO3 is 97.75%.
基金Project(2003AA302210) support by the National High-Tech Research and Development Program of ChinaProject(05JJ20014) supported by the Natural Science Foundation of Hunan Province, China
文摘The effects of aspartic acid on the crystal growth, morphology of hydroxyapatite(HAP) crystal were investigated, and the inhibition mechanism of aspartic acid on the crystal growth of hydroxyapatite was studied. The results show that the crystal growth rate of HAP decreases with the increase of the aspartic acid concentration, and the HAP crystal is thinner significantly compared with that without amino acid, which is mainly due to the (1 010) surface of HAP crystal being inhibited by the aspartic acids. The calculation analysis indicates that the crystal growth mechanism of HAP, following surface diffusion controlled mechanism, is not changed due to the presence of aspartic acid. AFM result shows that the front of terrace on vicinal growth hillocks is pinned, which suggests that the aspartic acid is adsorbed onto the (1 010) surface of HAP and interacts with the Ca2+ ions of HAP surface, so as to block the growth active sites and result in retarding of the growth of HAP crystal.
基金Provided financial assistance by"Hundred Talented Projects"of Shanghai Health Bureau (No. 97BR016)
文摘Objective: To observe and elucidate the neuroprotective effect of Xingnaojing (XNJ) injection on hippocampal N-methyl-D-aspartic acid (NMDA) receptors of focal cerebral ischemia in rats. Methods: Cerebral ischemia was established by occluding the middle cerebral artery with an intraluminal suture technique in rats. Neurological deficit score, infarct volume and quantity of NMDA receptors were estimated in all groups and compared. Results: After being treated with XNJ, the score decreased in the initial 6 hours and infarct volume decreased in 24 hours. And within 24 hours, the quantity of NMDA receptors obviously decreased compared with the model group (P<0. 01) It indicated that XNJ could ameliorate neurological behavior of middle cerebral artery occlusion rats and down-regulate the expression of hippocampal NMDA receptors. Conclusion: The neuroprotective effect of XNJ on focal cerebral ischemia is possibly related to down-regulating the expression of NMDA receptors in rats.
