[Objective] This study was conducted to evaluate the effect of 1-methylcy- clopropene (1-MCP) on fruit firmness, and the activity of the enzymes involved in ethylene metabolism and membrane lipid peroxidation. [Meth...[Objective] This study was conducted to evaluate the effect of 1-methylcy- clopropene (1-MCP) on fruit firmness, and the activity of the enzymes involved in ethylene metabolism and membrane lipid peroxidation. [Method] The nearly ripe fruits of the papaya cultivar Risheng were randomly assigned to one of four groups. Two groups were treated under hypobaric and hypoxic (HH) atmosphere condition for six hours, and immediately soaked in deionized water (HH alone), or fumigated with 2.0 mg/L 1-MCP (HH+I-MCP) for 24 h. The other two groups untreated under HH condition were also soaked in deionized water (negative control), or fumigated with 2.0 mg/L 1-MCP (1-MCP alone) for 24 h. After that, the fruits of all the four treatments were stored at room temperature (23+1) ℃. Cell membrane permeability, fruit firmness, respiration rate, ethylene release rate, SOD activity, POD activity, CAT activity, MAD content and LOX activity were measured once every three days during storage. [Result] Treatment with 1-MCP delayed the occurrence of the peaks of respiration rate and ethylene release rate, significantly reduced the accumulation of malondialdehyde (MDA), and inhibited the decrease in papaya fruit firmness. Compared with the control, 1-MCP treatment significantly increased the SOD (su- peroxide dismutase), POD (peroxidase) and CAT (catalase) activity, reduced the ac- tivity of lipoxygenase (LOX), a product of lipid peroxidatlon in membranes, and in- hibited ethylene biosynthesis, thus delaying the aging process and prolonging the storage life of papaya fruits. [Conclusion] The results will provide a theoretical basis for analvzina the key factors controllinq postharvest maturity and aging of papaya fruits.展开更多
FT Ⅰ (AAAAGGGGAAGCAGAG), a poly purine ele-ment within the myloid-lineage specific enhancer (En 1) of the mouse myeloperoxidase gene [1, 2] has been fur-ther characterised. 1, FT Ⅰ functions as a myeloid-lineage spe...FT Ⅰ (AAAAGGGGAAGCAGAG), a poly purine ele-ment within the myloid-lineage specific enhancer (En 1) of the mouse myeloperoxidase gene [1, 2] has been fur-ther characterised. 1, FT Ⅰ functions as a myeloid-lineage specific transcription regulatory element; 2, WEHI 3BD+ cells have higher binding activity to FT Ⅰ and express the proteins which could form the unique DNA-protein com-plex(es) of FT Ⅰ;. 3, The essential sequence for the specific DNA-protein interactions of FT Ⅰ is AAAAGGGGAAGC; 4, South-western analysis in conjunction with the compe-tition assay of the proteins binding to FT Ⅰ, has revealed a 28 kd protein in WEHI 3BD+ cells that displays the properties of the putative transcription factor which acts through FT Ⅰ. These new findings have demonstrated both the functional myeloid-lineage specificity and the novelty of FT Ⅰ.展开更多
Objective.To investigate the effect of peroxis ome proliferator-activated recept ors(PPARs )activators on plasminogen activator inhibitor ty pe-1(PAI-1)expression in human umbilical vein e ndothelial cells and the pos...Objective.To investigate the effect of peroxis ome proliferator-activated recept ors(PPARs )activators on plasminogen activator inhibitor ty pe-1(PAI-1)expression in human umbilical vein e ndothelial cells and the possi-ble mechanism.Methods.Human umbilical vein endothelial ce lls(HUVECs )were obtained from normal fetus,and cul-tured conventionally.Then the HUVECs were exposed to test agents(linolenic acid,linoleic acid,oleic acid,stearic acid and prostaglandin J 2 respectively)in varying concentrations with fresh media.RT -PCR and ELISA were applied to determine the expression of PPARs and PAI-1in HUVECs.Results.PPARα,PPARδand PPARγmRNA were detected by using RT-PCR in HUVECs.Treatment of HUVECs with PPARαand PPARγactivators---linolenic acid,linoleic acid,oleic acid and prostaglandin J 2 respectively,but not with stearic a cid could augment PAI-I mRNA expression and protein secretion in a concentration-dependent manner.However,the mRNA expressions of 3subclasses of PPAR with their activators in HUVECs were not changed compared w ith controls.Conclusion.HUVECs express PPARs.PPARs activators may increase PAI-1expression in ECs,but the underlying mechanism remains uncle ar.Although PPARs expression was not enhanced after stimulated by their activators in ECs,the role of functionally active PPARs in regulating PA I-1expression in ECs needs to be further investigated by using transient gen e transfection assay.展开更多
The epoxidation of methyl oleate(MO)was conducted in the presence of aqueous H2O2 as the oxidant and hierarchical TS-1(HTS-1)as the catalyst;the catalyst was synthesized using polyquaternium-6 as the mesopore template...The epoxidation of methyl oleate(MO)was conducted in the presence of aqueous H2O2 as the oxidant and hierarchical TS-1(HTS-1)as the catalyst;the catalyst was synthesized using polyquaternium-6 as the mesopore template.The effects of various parameters,i.e.,H2O2/C=C molar ratio,oxidant concentration,amount of the catalyst,reaction temperature,and time,were systematically studied.Furthermore,response surface methodology(RSM)was used to optimize the conditions to maximize the yield of epoxy MO and to evaluate the significance and interplay of the factors affecting the epoxy MO production.The H2O2/C=C molar ratio and catalyst amount were the determining factors for MO epoxidation,wherein the maximum yield of epoxy MO reached 94.9%over HTS-1 under the optimal conditions.展开更多
This article focuses on the current underlying of molecular mechanisms of the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) mediated pathway and discuss possible therapeutic benefits of inc...This article focuses on the current underlying of molecular mechanisms of the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) mediated pathway and discuss possible therapeutic benefits of increased mitochondrial biogenesis in compensating for mitochondrial dysfunction and ameliorating aging and aging-related diseases. PGC-1α is the master transcription regulator that stimulates mitochondrial biogenesis, by upregulating nuclear respiratory factors and mitochondrial transcription factor A, leading to increased mitochondrial DNA replication and gene transcription. PGC-1α also regulates cellular oxidant-antioxidant homeostasis by stimulating the gene expression of superoxide dismutase-2, catalase, glutathione peroxidase 1, and uncoupling protein. Recent reports from muscle-specific PGC-1α overexpression underline the benefit of PGC-1α in muscle atrophy and sarcopenia, during which PGC-1α enhanced mitochondrial biogenic pathway and reduced oxidative damage. Thus, PGC-1α seems to have a protective role against aging associated skeletal muscle deterioration.展开更多
Titanium silicalite-1(TS-1)films were synthesized on stainless steel plate,glass slide and monolith supports via an in-situ hydrothermal method.Characterization data showed that the formation of TS-1 films was easier ...Titanium silicalite-1(TS-1)films were synthesized on stainless steel plate,glass slide and monolith supports via an in-situ hydrothermal method.Characterization data showed that the formation of TS-1 films was easier on the porous flat support with rough surface such as monolith than on the smooth non-porous supports like glass slide and stainless steel plate.The film on the monolith had the highest uniformity and smallest size of crystals.The catalytic property of monolithsupported film was tested for epoxidation of allyl chloride(ACH)by H2O2in a fixed bed reactor.Under the condition of a methanol(solvent)/ACH(90% )/H2O2(30% )ratio of 12:1:1,a LHSV of 1.35 h-1and a temperature of 318 K,the conversion of allyl chloride and the selectivity to epichlorohydrin reached 79% and 51% ,respectively.展开更多
AIM:To investigate the effects of heme oxygenase(HO)-1 on liver fibrosis and the expression of peroxisome proliferator-activated receptor gamma(PPARγ) and nuclear factor-kappa B(NF-κB) in rats.METHODS:Sixty Wistar r...AIM:To investigate the effects of heme oxygenase(HO)-1 on liver fibrosis and the expression of peroxisome proliferator-activated receptor gamma(PPARγ) and nuclear factor-kappa B(NF-κB) in rats.METHODS:Sixty Wistar rats were used to construct liver fibrosis models and were randomly divided into 5 groups:group A(normal,untreated),group B(model for 4 wk,untreated),group C(model for 6 wk,untreated),group D [model for 6 wk,treated with zinc protoporphyrin Ⅸ(ZnPP-Ⅸ) from week 4 to week 6],group E(model for 6 wk,treated with hemin from week 4 to week 6).Next,liver injury was assessed by measuring serum alanine aminotransferase(ALT),aspartate aminotransferase(AST) and albumin levels.The degree of hepatic fibrosis was evaluated by measuring serum hyaluronate acid(HA),type Ⅳ collagen(Ⅳ-C) and by histological examination.Hydroxyproline(Hyp) content in the liver homogenate was determined.The expres-sion levels of alpha-smooth muscle actin(α-SMA) in liver tissue were measured by real-time quantitative polymerase chain reaction(RT-PCR).The expression levels of PPARγ and NF-κB were determined by RT-PCR and Western blotting.RESULTS:The expression of HO-1 increased with the development of fibrosis.Induction of HO-1 by hemin significantly attenuated the severity of liver injury and the levels of liver fibrosis as compared with inhibition of HO-1 by ZnPP-Ⅸ.The concentrations of serum ALT,AST,HA and Ⅳ-C in group E decreased compared with group C and group D(P < 0.01).Amount of Hyp and α-SMA in the liver tissues in group E decreased compared with group C(0.62 ± 0.14 vs 0.84 ± 0.07,1.42 ± 0.17 vs 1.84 ± 0.17,respectively,P < 0.01) and group D(0.62 ± 0.14 vs 1.11 ± 0.16,1.42 ± 0.17 vs 2.56 ± 0.37,respectively,P < 0.01).The expression of PPARγ at levels of transcription and translation decreased with the development of fibrosis especially in group D;and it increased in group E compared with groups C and D(0.88 ± 0.15 vs 0.56 ± 0.19,0.88 ± 0.15 vs 0.41 ± 0.11,respectively,P < 0.01).The expression of NF-κB increased with the development of fibrosis especially in group D;and it decreased in group E compared with groups C and D(1.43 ± 0.31 vs 1.89 ± 0.29,1.43 ± 0.31 vs 2.53 ± 0.54,respectively,P < 0.01).CONCLUSION:Our data demonstrate a potential mechanism that HO-1 can prevent liver fibrosis by enhancing the expression of PPARγ and decreasing the expression of NF-κB in liver tissues.展开更多
The inhibitory effect of the methanolic extract of the root of Aegle marmelos (MERA) and its constituents on the lipid peroxidation in vivo and in vitro were studied. The results suggested that MERA increased the acti...The inhibitory effect of the methanolic extract of the root of Aegle marmelos (MERA) and its constituents on the lipid peroxidation in vivo and in vitro were studied. The results suggested that MERA increased the activities of superoxide dismutase (SOD) and GSH-peroxidase in the liver cytosol of mice, but showed no significant effect on the activity of catalase, and one of its major constituents, 4-methoxy-1-methyl-2-quinolone (MMQ) increased the activity of SOD in liver tissue of mice intoxicated with FeCl2-ascorbic acid (AA)-ADP in vivo. Various constituents isolated from the root of title plant inhibited the lipid peroxidation in rat liver homogenate, which was in vitro induced by FeCl2-ascorbic acid, CCl4-NADPH, or ADP- NADPH. Of the test compounds, MMQ and its derivatives integriquinolone were similar to (-tocopherol in inhibiting MDA production in rat liver microsomes induced by Fe2+-ascorbate, CCl4-NADPH, or ADP-NADPH.展开更多
This review summarized our recent studies on involvement of tissue type plasminogen activator(tPA)and plasminogen activator inhibitor type 1(PAI-1) in process of ovulation.We have demonstrated that 1)hCG induces ovula...This review summarized our recent studies on involvement of tissue type plasminogen activator(tPA)and plasminogen activator inhibitor type 1(PAI-1) in process of ovulation.We have demonstrated that 1)hCG induces ovulation and coordinated tPA and PAI-1 gene expression in both rat and monkey ovaries;(2) GnRH and FSH are also capable of inducing ovulation by increasing ovarian tPA and PAI-1 gene expression in the same manner as hCG does;(3)Compounds which increase tPA production can induce oviation while compounds which decrease tPA and/or increase PAI-1 expression inhibit ovulation. Based on the data provided,a working model on the involvement of tPA in ovulation is presented.展开更多
A transition diagram is used to describe the behavior of systems. Birth-death equations were derived from transition diagram depicting the state of the birth-death processes. Queue models and characteristics of queue ...A transition diagram is used to describe the behavior of systems. Birth-death equations were derived from transition diagram depicting the state of the birth-death processes. Queue models and characteristics of queue models are also derivable from birth-death processes. These queue models consist of mathematical formulas and relationships that can be used to determine the operating characteristics (performance measures) for a waiting line. Schematic and transition diagrams of different single server queue models were shown. Relationships between birth-death processes, waiting lines (queues) and transition diagrams were given. While M/M/I/K queue model states was limited by K customers and had (K+I) states, M/M/1/1 queue model had only two states. M/G/1/∝/∝ and M/M/1/∝/∝ shared similar characteristics. Many ideal queuing situations employ M/M/1 queueing model.展开更多
A transmission bottleneck occurs during each human immunodeficiency virus(HIV) transmission event, which allows only a few viruses to establish new infection. However, the genetic characteristics of the transmitted vi...A transmission bottleneck occurs during each human immunodeficiency virus(HIV) transmission event, which allows only a few viruses to establish new infection. However, the genetic characteristics of the transmitted viruses that are preferentially selected have not been fully elucidated. Here, we analyzed amino acids changes in the envelope protein during simian immunodeficiency virus(SIV)/HIV deep transmission history and current HIV evolution within the last 15–20 years. Our results confirmed that the V1V2 region of gp120 protein, particularly V1, was preferentially selected. A shorter V1 region was preferred during transmission history, while during epidemic, HIV may evolve to an expanded V1 region gradually and thus escape immune recognition. We then constructed different HIV-1 V1 mutants using different HIV-1 subtypes to elucidate the role of the V1 region in envelope function. We found that the V1 region, although highly variable, was indispensable for virus entry and infection, probably because V1 deletion mutants exhibited impaired processing of gp160 into mature gp120 and gp41. Additionally, the V1 region affected Env incorporation. These results indicated that the V1 region played a critical role in HIV transmission and infection.展开更多
Objective: To evaluate the antioxidation of dihydrobiopterin reductase and to explore the effect of A278C mutation of the quinoid dihydropteridine reductase(QDPR) gene on its antioxidant activity. Methods: First, plas...Objective: To evaluate the antioxidation of dihydrobiopterin reductase and to explore the effect of A278C mutation of the quinoid dihydropteridine reductase(QDPR) gene on its antioxidant activity. Methods: First, plasmids with different genes(wild and mutant QDPR) were constructed. After gene sequencing, they were transfected into human kidney cells(HEK293T). Then, the intracellular production of reactive oxygen species(ROS) and tetrahydrobiopterin(BH4) was detected after cells were harvested. Activations of nicotinamide adenine dinucleotide phosphate oxidase 4(NOX4), glutathione peroxidase 3(GPX3), and superoxide dismutase 1(SOD1) were analyzed to observe the oxidative stress after transfection. The expression of the neuronal nitric oxide synthase(n NOS) gene was analyzed by semiquantitative reverse-transcription polymerase chain reaction(RT-PCR). We also detected the activation of transforming growth factor β1(TGF-β1) by enzyme-linked immunosorbent assay(ELISA) to observe the connection of TGF-β1 and oxidative stress. Results: The exogenous wild-type QDPR significantly decreased the expression of n NOS, NOX4, and TGF-β1 and induced the expression of SOD1 and GPX3, but the mutated QDPR lost this function and resulted in excessive ROS production. Our data also suggested that the influence on the level of BH4 had no significant difference between mutated and the wild-type QDPR transfection. Conclusions: Wild-type QDPR played an important role in protecting against oxidative stress, but mutant QDPR failed to have these beneficial effects.展开更多
文摘[Objective] This study was conducted to evaluate the effect of 1-methylcy- clopropene (1-MCP) on fruit firmness, and the activity of the enzymes involved in ethylene metabolism and membrane lipid peroxidation. [Method] The nearly ripe fruits of the papaya cultivar Risheng were randomly assigned to one of four groups. Two groups were treated under hypobaric and hypoxic (HH) atmosphere condition for six hours, and immediately soaked in deionized water (HH alone), or fumigated with 2.0 mg/L 1-MCP (HH+I-MCP) for 24 h. The other two groups untreated under HH condition were also soaked in deionized water (negative control), or fumigated with 2.0 mg/L 1-MCP (1-MCP alone) for 24 h. After that, the fruits of all the four treatments were stored at room temperature (23+1) ℃. Cell membrane permeability, fruit firmness, respiration rate, ethylene release rate, SOD activity, POD activity, CAT activity, MAD content and LOX activity were measured once every three days during storage. [Result] Treatment with 1-MCP delayed the occurrence of the peaks of respiration rate and ethylene release rate, significantly reduced the accumulation of malondialdehyde (MDA), and inhibited the decrease in papaya fruit firmness. Compared with the control, 1-MCP treatment significantly increased the SOD (su- peroxide dismutase), POD (peroxidase) and CAT (catalase) activity, reduced the ac- tivity of lipoxygenase (LOX), a product of lipid peroxidatlon in membranes, and in- hibited ethylene biosynthesis, thus delaying the aging process and prolonging the storage life of papaya fruits. [Conclusion] The results will provide a theoretical basis for analvzina the key factors controllinq postharvest maturity and aging of papaya fruits.
文摘FT Ⅰ (AAAAGGGGAAGCAGAG), a poly purine ele-ment within the myloid-lineage specific enhancer (En 1) of the mouse myeloperoxidase gene [1, 2] has been fur-ther characterised. 1, FT Ⅰ functions as a myeloid-lineage specific transcription regulatory element; 2, WEHI 3BD+ cells have higher binding activity to FT Ⅰ and express the proteins which could form the unique DNA-protein com-plex(es) of FT Ⅰ;. 3, The essential sequence for the specific DNA-protein interactions of FT Ⅰ is AAAAGGGGAAGC; 4, South-western analysis in conjunction with the compe-tition assay of the proteins binding to FT Ⅰ, has revealed a 28 kd protein in WEHI 3BD+ cells that displays the properties of the putative transcription factor which acts through FT Ⅰ. These new findings have demonstrated both the functional myeloid-lineage specificity and the novelty of FT Ⅰ.
文摘Objective.To investigate the effect of peroxis ome proliferator-activated recept ors(PPARs )activators on plasminogen activator inhibitor ty pe-1(PAI-1)expression in human umbilical vein e ndothelial cells and the possi-ble mechanism.Methods.Human umbilical vein endothelial ce lls(HUVECs )were obtained from normal fetus,and cul-tured conventionally.Then the HUVECs were exposed to test agents(linolenic acid,linoleic acid,oleic acid,stearic acid and prostaglandin J 2 respectively)in varying concentrations with fresh media.RT -PCR and ELISA were applied to determine the expression of PPARs and PAI-1in HUVECs.Results.PPARα,PPARδand PPARγmRNA were detected by using RT-PCR in HUVECs.Treatment of HUVECs with PPARαand PPARγactivators---linolenic acid,linoleic acid,oleic acid and prostaglandin J 2 respectively,but not with stearic a cid could augment PAI-I mRNA expression and protein secretion in a concentration-dependent manner.However,the mRNA expressions of 3subclasses of PPAR with their activators in HUVECs were not changed compared w ith controls.Conclusion.HUVECs express PPARs.PPARs activators may increase PAI-1expression in ECs,but the underlying mechanism remains uncle ar.Although PPARs expression was not enhanced after stimulated by their activators in ECs,the role of functionally active PPARs in regulating PA I-1expression in ECs needs to be further investigated by using transient gen e transfection assay.
基金supported by the Evonik Industries AGthe Program for New Century Excellent Talents in University(NCET-04-0270)~~
文摘The epoxidation of methyl oleate(MO)was conducted in the presence of aqueous H2O2 as the oxidant and hierarchical TS-1(HTS-1)as the catalyst;the catalyst was synthesized using polyquaternium-6 as the mesopore template.The effects of various parameters,i.e.,H2O2/C=C molar ratio,oxidant concentration,amount of the catalyst,reaction temperature,and time,were systematically studied.Furthermore,response surface methodology(RSM)was used to optimize the conditions to maximize the yield of epoxy MO and to evaluate the significance and interplay of the factors affecting the epoxy MO production.The H2O2/C=C molar ratio and catalyst amount were the determining factors for MO epoxidation,wherein the maximum yield of epoxy MO reached 94.9%over HTS-1 under the optimal conditions.
文摘This article focuses on the current underlying of molecular mechanisms of the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) mediated pathway and discuss possible therapeutic benefits of increased mitochondrial biogenesis in compensating for mitochondrial dysfunction and ameliorating aging and aging-related diseases. PGC-1α is the master transcription regulator that stimulates mitochondrial biogenesis, by upregulating nuclear respiratory factors and mitochondrial transcription factor A, leading to increased mitochondrial DNA replication and gene transcription. PGC-1α also regulates cellular oxidant-antioxidant homeostasis by stimulating the gene expression of superoxide dismutase-2, catalase, glutathione peroxidase 1, and uncoupling protein. Recent reports from muscle-specific PGC-1α overexpression underline the benefit of PGC-1α in muscle atrophy and sarcopenia, during which PGC-1α enhanced mitochondrial biogenic pathway and reduced oxidative damage. Thus, PGC-1α seems to have a protective role against aging associated skeletal muscle deterioration.
基金the Natural Science Foundation of Shanxi Province,China(No.2011011023-2)for financial support
文摘Titanium silicalite-1(TS-1)films were synthesized on stainless steel plate,glass slide and monolith supports via an in-situ hydrothermal method.Characterization data showed that the formation of TS-1 films was easier on the porous flat support with rough surface such as monolith than on the smooth non-porous supports like glass slide and stainless steel plate.The film on the monolith had the highest uniformity and smallest size of crystals.The catalytic property of monolithsupported film was tested for epoxidation of allyl chloride(ACH)by H2O2in a fixed bed reactor.Under the condition of a methanol(solvent)/ACH(90% )/H2O2(30% )ratio of 12:1:1,a LHSV of 1.35 h-1and a temperature of 318 K,the conversion of allyl chloride and the selectivity to epichlorohydrin reached 79% and 51% ,respectively.
文摘AIM:To investigate the effects of heme oxygenase(HO)-1 on liver fibrosis and the expression of peroxisome proliferator-activated receptor gamma(PPARγ) and nuclear factor-kappa B(NF-κB) in rats.METHODS:Sixty Wistar rats were used to construct liver fibrosis models and were randomly divided into 5 groups:group A(normal,untreated),group B(model for 4 wk,untreated),group C(model for 6 wk,untreated),group D [model for 6 wk,treated with zinc protoporphyrin Ⅸ(ZnPP-Ⅸ) from week 4 to week 6],group E(model for 6 wk,treated with hemin from week 4 to week 6).Next,liver injury was assessed by measuring serum alanine aminotransferase(ALT),aspartate aminotransferase(AST) and albumin levels.The degree of hepatic fibrosis was evaluated by measuring serum hyaluronate acid(HA),type Ⅳ collagen(Ⅳ-C) and by histological examination.Hydroxyproline(Hyp) content in the liver homogenate was determined.The expres-sion levels of alpha-smooth muscle actin(α-SMA) in liver tissue were measured by real-time quantitative polymerase chain reaction(RT-PCR).The expression levels of PPARγ and NF-κB were determined by RT-PCR and Western blotting.RESULTS:The expression of HO-1 increased with the development of fibrosis.Induction of HO-1 by hemin significantly attenuated the severity of liver injury and the levels of liver fibrosis as compared with inhibition of HO-1 by ZnPP-Ⅸ.The concentrations of serum ALT,AST,HA and Ⅳ-C in group E decreased compared with group C and group D(P < 0.01).Amount of Hyp and α-SMA in the liver tissues in group E decreased compared with group C(0.62 ± 0.14 vs 0.84 ± 0.07,1.42 ± 0.17 vs 1.84 ± 0.17,respectively,P < 0.01) and group D(0.62 ± 0.14 vs 1.11 ± 0.16,1.42 ± 0.17 vs 2.56 ± 0.37,respectively,P < 0.01).The expression of PPARγ at levels of transcription and translation decreased with the development of fibrosis especially in group D;and it increased in group E compared with groups C and D(0.88 ± 0.15 vs 0.56 ± 0.19,0.88 ± 0.15 vs 0.41 ± 0.11,respectively,P < 0.01).The expression of NF-κB increased with the development of fibrosis especially in group D;and it decreased in group E compared with groups C and D(1.43 ± 0.31 vs 1.89 ± 0.29,1.43 ± 0.31 vs 2.53 ± 0.54,respectively,P < 0.01).CONCLUSION:Our data demonstrate a potential mechanism that HO-1 can prevent liver fibrosis by enhancing the expression of PPARγ and decreasing the expression of NF-κB in liver tissues.
文摘The inhibitory effect of the methanolic extract of the root of Aegle marmelos (MERA) and its constituents on the lipid peroxidation in vivo and in vitro were studied. The results suggested that MERA increased the activities of superoxide dismutase (SOD) and GSH-peroxidase in the liver cytosol of mice, but showed no significant effect on the activity of catalase, and one of its major constituents, 4-methoxy-1-methyl-2-quinolone (MMQ) increased the activity of SOD in liver tissue of mice intoxicated with FeCl2-ascorbic acid (AA)-ADP in vivo. Various constituents isolated from the root of title plant inhibited the lipid peroxidation in rat liver homogenate, which was in vitro induced by FeCl2-ascorbic acid, CCl4-NADPH, or ADP- NADPH. Of the test compounds, MMQ and its derivatives integriquinolone were similar to (-tocopherol in inhibiting MDA production in rat liver microsomes induced by Fe2+-ascorbate, CCl4-NADPH, or ADP-NADPH.
文摘This review summarized our recent studies on involvement of tissue type plasminogen activator(tPA)and plasminogen activator inhibitor type 1(PAI-1) in process of ovulation.We have demonstrated that 1)hCG induces ovulation and coordinated tPA and PAI-1 gene expression in both rat and monkey ovaries;(2) GnRH and FSH are also capable of inducing ovulation by increasing ovarian tPA and PAI-1 gene expression in the same manner as hCG does;(3)Compounds which increase tPA production can induce oviation while compounds which decrease tPA and/or increase PAI-1 expression inhibit ovulation. Based on the data provided,a working model on the involvement of tPA in ovulation is presented.
文摘A transition diagram is used to describe the behavior of systems. Birth-death equations were derived from transition diagram depicting the state of the birth-death processes. Queue models and characteristics of queue models are also derivable from birth-death processes. These queue models consist of mathematical formulas and relationships that can be used to determine the operating characteristics (performance measures) for a waiting line. Schematic and transition diagrams of different single server queue models were shown. Relationships between birth-death processes, waiting lines (queues) and transition diagrams were given. While M/M/I/K queue model states was limited by K customers and had (K+I) states, M/M/1/1 queue model had only two states. M/G/1/∝/∝ and M/M/1/∝/∝ shared similar characteristics. Many ideal queuing situations employ M/M/1 queueing model.
基金supported by the International Science & Technology Cooperation Program of China (2011DFA31030)Deutsche Forschungsgemeinschaft (Transregio TRR60),National Natural Science Foundation of China (No.81461130019)
文摘A transmission bottleneck occurs during each human immunodeficiency virus(HIV) transmission event, which allows only a few viruses to establish new infection. However, the genetic characteristics of the transmitted viruses that are preferentially selected have not been fully elucidated. Here, we analyzed amino acids changes in the envelope protein during simian immunodeficiency virus(SIV)/HIV deep transmission history and current HIV evolution within the last 15–20 years. Our results confirmed that the V1V2 region of gp120 protein, particularly V1, was preferentially selected. A shorter V1 region was preferred during transmission history, while during epidemic, HIV may evolve to an expanded V1 region gradually and thus escape immune recognition. We then constructed different HIV-1 V1 mutants using different HIV-1 subtypes to elucidate the role of the V1 region in envelope function. We found that the V1 region, although highly variable, was indispensable for virus entry and infection, probably because V1 deletion mutants exhibited impaired processing of gp160 into mature gp120 and gp41. Additionally, the V1 region affected Env incorporation. These results indicated that the V1 region played a critical role in HIV transmission and infection.
基金supported by the National Natural Science Foundation of China(No.81130066)the International Cooperation and Exchanges of the National Natural Science Foundation of China(No.81620108031)
文摘Objective: To evaluate the antioxidation of dihydrobiopterin reductase and to explore the effect of A278C mutation of the quinoid dihydropteridine reductase(QDPR) gene on its antioxidant activity. Methods: First, plasmids with different genes(wild and mutant QDPR) were constructed. After gene sequencing, they were transfected into human kidney cells(HEK293T). Then, the intracellular production of reactive oxygen species(ROS) and tetrahydrobiopterin(BH4) was detected after cells were harvested. Activations of nicotinamide adenine dinucleotide phosphate oxidase 4(NOX4), glutathione peroxidase 3(GPX3), and superoxide dismutase 1(SOD1) were analyzed to observe the oxidative stress after transfection. The expression of the neuronal nitric oxide synthase(n NOS) gene was analyzed by semiquantitative reverse-transcription polymerase chain reaction(RT-PCR). We also detected the activation of transforming growth factor β1(TGF-β1) by enzyme-linked immunosorbent assay(ELISA) to observe the connection of TGF-β1 and oxidative stress. Results: The exogenous wild-type QDPR significantly decreased the expression of n NOS, NOX4, and TGF-β1 and induced the expression of SOD1 and GPX3, but the mutated QDPR lost this function and resulted in excessive ROS production. Our data also suggested that the influence on the level of BH4 had no significant difference between mutated and the wild-type QDPR transfection. Conclusions: Wild-type QDPR played an important role in protecting against oxidative stress, but mutant QDPR failed to have these beneficial effects.