AIM: To investigate the expression of gonadotropin-releasing hormone (GnRH) receptor and the effects of GnRH analog(alarelin) on proliferation of cultured gastric smooth muscle cells (GSMC) of rats. METHODS: Immunohis...AIM: To investigate the expression of gonadotropin-releasing hormone (GnRH) receptor and the effects of GnRH analog(alarelin) on proliferation of cultured gastric smooth muscle cells (GSMC) of rats. METHODS: Immunohistochemical ABC methods and in situ hybridization methods were used to dectect protein and mRNA expression of GnRH receptor in GSMC, respectively. Techniques of cell culture, OD value of MTT test, measure of ^3H-TdR incorporation, average fluorescent values of proliferating cell nuclear antigen (PCNA) and flow cytometric DNA analysis were used in the experiment. RESULTS: The cultured GSMC of rats showed immunoreactivity for GnRH receptor; positive staining was located in cytoplasm. GnRH receptor mRNA hybridized signals were also detected in cytoplasm. When alarelin (10^-9, 10^-7, 10^-5 mol/L) was administered into the medium and incubated for 24 h, OD value of MTT, ^3H-TdR incorporation and average fluorescent values of PCNA all decreased significantly as compared with the control group (P<0.05). The maximum inhibitory effect on cell proliferation was achieved a concentration of 10s mol/L and it acted in a dose-dependent manner. Flow cytometric DNA analysis revealed that alarelin could significantly enhance ratio of G1 phase and decrease ratio of S phase of GSMC of rats (P<0.05).The maximum inhibitory effect on ratio of S phase was at the concentration of 10-s mol/L and also acted in a dose-dependent manner. CONCLUSION: Our data suggest that GnRH receptor can be expressed by GSMC of rats. GnRH analogue can directly inhibit proliferation and DNA synthesis of rat GSMC through GnRH receptors.展开更多
Gas exchange, water relations and leaf chemical characteristics were examined of twodominant psammophytes: Artemisia frigida Willd and A halodendron Turcz. ex Bess in Horqin sandy land, NeiMongol, China under differen...Gas exchange, water relations and leaf chemical characteristics were examined of twodominant psammophytes: Artemisia frigida Willd and A halodendron Turcz. ex Bess in Horqin sandy land, NeiMongol, China under different water regimes. The measurements were conducted by submitting the plantsto five different irrigation levels. A. fTigida was characterized by lower photosynthetic rate (Pn), lowertranspiration rate ( TR and lower shoot water potential (ψuw) relative to A. halodendron. Foliage of A frigdahad higher values of relative water deficit (RWD), bound water content (BWC), ratio of bound water contentto free water content (BWC/FWC) and integrated drought-resistant index (DI than that of A. halodendron.Water relations differed significantly between two species in response to soil water availability. ψw, BWCand BWC/FWC ratio of A halodendron exhibited large variation with gradual decrease of soil moisture.However, in terms of these parameters, A. fRIGIDA was characterized by higher capacity of water holding anddrought tolerance relative to A halodendron. Proline and total soluble sugar contents of A frigida and Ahalodendron tended to increase with decrease of soil moisture and the former had a larger increaseamplitude than the latter. This shows that A frigida has a higher osmotic regulation ability than A halodendron.Under the extreme drought conditions, ψw, RWD, BWC and BWC/FWC of two species were approximate,but soluble proteins degraded largely. A large amount of accumulation of organic matter, proline and totalsoluble sugars were observed in both A halodendron and A frigida. The increase in proline and total solublesugar contents and soluble protein degradation of A frigida far exceeded those of A. halodendron. Webelieve that the accumulated materials at this moment are mostly of nutrient substances available for therecovery of plants after the drought. This is one of the reasons why A halodendron plants died while Afrigida plants survived under extremely drought condition. Our results suggest that these ecophysiologicalfeatures of A frigida are favorable to its growth in the fixed sandy land compared with A halodendron, whichoften lost its dominance due to weak competition for water sources under lower soil water availability andare major factors resulting in replacement of A. halodendron by A. frigida in the later stage of sandyvegetation succession in Horqin.展开更多
In this study, Mn(Ⅱ) as a mimetic enzyme of horseradish peroxidase (HRP) was applied to the determination of hydrogen peroxide (H2O2). The method introduced in this paper is based on Mn(Ⅱ)’s catalytic effect on t...In this study, Mn(Ⅱ) as a mimetic enzyme of horseradish peroxidase (HRP) was applied to the determination of hydrogen peroxide (H2O2). The method introduced in this paper is based on Mn(Ⅱ)’s catalytic effect on the oxidation of 4-aminoantipyrine(4-AAP) with modified Trinder’s reagent N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3, 5-dimethoxyaniline(DAOS) by H2O2. By coupling this mimetic catalytic reaction with the catalytic reaction of glucose oxidase (GOD), glucose can be detected. Under optimum conditions, the calibration graphs for the determination of H2O2 and glucose are in the range of 1.0×10-3?1.0×10-1 mol/L and 1.0×10-3?14×10-3 mol/L respectively. The detection limit is 5.9×10-4 mol/L for H2O2 and is 9.2×10-4 mol/L for glucose. The feasibility of Mn ( II ) as a HRP mimetic enzyme in practical clinical analysis has been proven in the determination of glucose in human serum. So far, Mn ( II ) is the simplest and the most inexpensive mimetic enzyme.展开更多
A primitive orthorhombic crystal form of acylamino acid releasing enzyme/lipase (APE1547) from hyperthermophilic archaeon Aeropyrum pernix strain K1 has been obtained at 291 K. The diffraction pattern of the crystal e...A primitive orthorhombic crystal form of acylamino acid releasing enzyme/lipase (APE1547) from hyperthermophilic archaeon Aeropyrum pernix strain K1 has been obtained at 291 K. The diffraction pattern of the crystal extends to 0.27 nm resolution at 100 K using Cu Ka radiation. The crystal belongs to the space group P212121 with unit cell dimensions of a = 6.399, b = 10.439 and c = 16.953 nm. The presence of two molecules per asymmetric unit gives a crys-tal volume per protein mass (Vm) of 0.0022 nm3 Da-1 and a solvent content of 43% by volume. A full set of X-ray dif-fraction data were collected to 0.3 nm from the native crys-tal.展开更多
基金Supported by the Natural Science Foundation of China,No.39770388
文摘AIM: To investigate the expression of gonadotropin-releasing hormone (GnRH) receptor and the effects of GnRH analog(alarelin) on proliferation of cultured gastric smooth muscle cells (GSMC) of rats. METHODS: Immunohistochemical ABC methods and in situ hybridization methods were used to dectect protein and mRNA expression of GnRH receptor in GSMC, respectively. Techniques of cell culture, OD value of MTT test, measure of ^3H-TdR incorporation, average fluorescent values of proliferating cell nuclear antigen (PCNA) and flow cytometric DNA analysis were used in the experiment. RESULTS: The cultured GSMC of rats showed immunoreactivity for GnRH receptor; positive staining was located in cytoplasm. GnRH receptor mRNA hybridized signals were also detected in cytoplasm. When alarelin (10^-9, 10^-7, 10^-5 mol/L) was administered into the medium and incubated for 24 h, OD value of MTT, ^3H-TdR incorporation and average fluorescent values of PCNA all decreased significantly as compared with the control group (P<0.05). The maximum inhibitory effect on cell proliferation was achieved a concentration of 10s mol/L and it acted in a dose-dependent manner. Flow cytometric DNA analysis revealed that alarelin could significantly enhance ratio of G1 phase and decrease ratio of S phase of GSMC of rats (P<0.05).The maximum inhibitory effect on ratio of S phase was at the concentration of 10-s mol/L and also acted in a dose-dependent manner. CONCLUSION: Our data suggest that GnRH receptor can be expressed by GSMC of rats. GnRH analogue can directly inhibit proliferation and DNA synthesis of rat GSMC through GnRH receptors.
文摘Gas exchange, water relations and leaf chemical characteristics were examined of twodominant psammophytes: Artemisia frigida Willd and A halodendron Turcz. ex Bess in Horqin sandy land, NeiMongol, China under different water regimes. The measurements were conducted by submitting the plantsto five different irrigation levels. A. fTigida was characterized by lower photosynthetic rate (Pn), lowertranspiration rate ( TR and lower shoot water potential (ψuw) relative to A. halodendron. Foliage of A frigdahad higher values of relative water deficit (RWD), bound water content (BWC), ratio of bound water contentto free water content (BWC/FWC) and integrated drought-resistant index (DI than that of A. halodendron.Water relations differed significantly between two species in response to soil water availability. ψw, BWCand BWC/FWC ratio of A halodendron exhibited large variation with gradual decrease of soil moisture.However, in terms of these parameters, A. fRIGIDA was characterized by higher capacity of water holding anddrought tolerance relative to A halodendron. Proline and total soluble sugar contents of A frigida and Ahalodendron tended to increase with decrease of soil moisture and the former had a larger increaseamplitude than the latter. This shows that A frigida has a higher osmotic regulation ability than A halodendron.Under the extreme drought conditions, ψw, RWD, BWC and BWC/FWC of two species were approximate,but soluble proteins degraded largely. A large amount of accumulation of organic matter, proline and totalsoluble sugars were observed in both A halodendron and A frigida. The increase in proline and total solublesugar contents and soluble protein degradation of A frigida far exceeded those of A. halodendron. Webelieve that the accumulated materials at this moment are mostly of nutrient substances available for therecovery of plants after the drought. This is one of the reasons why A halodendron plants died while Afrigida plants survived under extremely drought condition. Our results suggest that these ecophysiologicalfeatures of A frigida are favorable to its growth in the fixed sandy land compared with A halodendron, whichoften lost its dominance due to weak competition for water sources under lower soil water availability andare major factors resulting in replacement of A. halodendron by A. frigida in the later stage of sandyvegetation succession in Horqin.
文摘In this study, Mn(Ⅱ) as a mimetic enzyme of horseradish peroxidase (HRP) was applied to the determination of hydrogen peroxide (H2O2). The method introduced in this paper is based on Mn(Ⅱ)’s catalytic effect on the oxidation of 4-aminoantipyrine(4-AAP) with modified Trinder’s reagent N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3, 5-dimethoxyaniline(DAOS) by H2O2. By coupling this mimetic catalytic reaction with the catalytic reaction of glucose oxidase (GOD), glucose can be detected. Under optimum conditions, the calibration graphs for the determination of H2O2 and glucose are in the range of 1.0×10-3?1.0×10-1 mol/L and 1.0×10-3?14×10-3 mol/L respectively. The detection limit is 5.9×10-4 mol/L for H2O2 and is 9.2×10-4 mol/L for glucose. The feasibility of Mn ( II ) as a HRP mimetic enzyme in practical clinical analysis has been proven in the determination of glucose in human serum. So far, Mn ( II ) is the simplest and the most inexpensive mimetic enzyme.
基金This work was supported by the 73 Project (Grant No. G1999075602).
文摘A primitive orthorhombic crystal form of acylamino acid releasing enzyme/lipase (APE1547) from hyperthermophilic archaeon Aeropyrum pernix strain K1 has been obtained at 291 K. The diffraction pattern of the crystal extends to 0.27 nm resolution at 100 K using Cu Ka radiation. The crystal belongs to the space group P212121 with unit cell dimensions of a = 6.399, b = 10.439 and c = 16.953 nm. The presence of two molecules per asymmetric unit gives a crys-tal volume per protein mass (Vm) of 0.0022 nm3 Da-1 and a solvent content of 43% by volume. A full set of X-ray dif-fraction data were collected to 0.3 nm from the native crys-tal.
