[Objectives]This study was conducted to obtain porcine gastrin-releasing peptide(GRP)fusion protein.[Methods]The constructed pET32a(+)-GRP plasmid was transformed into Escherichia coli BL21(DE3)competent cells to obta...[Objectives]This study was conducted to obtain porcine gastrin-releasing peptide(GRP)fusion protein.[Methods]The constructed pET32a(+)-GRP plasmid was transformed into Escherichia coli BL21(DE3)competent cells to obtain the pET32a(+)-GRP-BL21(DE3)fusion protein expression strain,which was induced with 0.5 mM IPTG at 25℃and 150 r/min for 12 h,and the His-tagged GRP fusion protein was detected by SDS-Page gel electrophoresis and Western Blot.[Results]After optimizing the IPTG-induced expression conditions,it was confirmed that the porcine GRP fusion protein was obtained,and the porcine GRP fusion protein was soluble,stable and highly active.[Conclusions]This study lays a foundation for the subsequent preparation of anti-pig GRP antibodies.展开更多
Recently, enzymatic peptide synthesis has drawn increasing attention due to its eco-friendly reagents and mild conditions, as compared to traditional chemical peptide synthesis. In this study, we successfully produced...Recently, enzymatic peptide synthesis has drawn increasing attention due to its eco-friendly reagents and mild conditions, as compared to traditional chemical peptide synthesis. In this study, we successfully produced an important antioxidant dipeptide precursor, BOC-Tyr-Ala, via a kinetically controlled enzymatic peptide synthesis reaction, catalyzed by the recombinant car- boxypeptidase Y （CPY） expressed in P. pastoris GS 115. In this reaction, the enzyme activity was 95.043 U/mL, and we used t-butyloxycarbonyl-L-tyrosine-methyl ester （BOC-Tyr-OMe） as the acyl donor and L-alanine （L-Ala） was the amino donor. We optimized the reaction conditions to be： 30 ℃, pH 9.5, organic phase （methanol）/aqueous phase = 1：20, BOC-Tyr-OMe 0.05 mol/L, Ala 0.5 mol/L, and a reaction time of 12 h. Under these conditions, the dipeptide yield reached 49.84%. Then, we established the kinetic model of the synthesis reaction in the form of Michaelis-Menten equation according to the con-centration-time curve during the process and the transpeptidation mechanism. We calculated the apparent Michaelis constant K^（app）mand the apparent maximum reaction rate r^（app）max to be 2.9946 x 10^-2 mol/L and 2.0406 x 10.2 mmol/（mL h）, respectively.展开更多
Amyloid-beta peptide is the main component of amyloid plaques, which are found in Alzhei- mer＇s disease. The generation and deposition of amyloid-beta is one of the crucial factors for the onset and progression of Al...Amyloid-beta peptide is the main component of amyloid plaques, which are found in Alzhei- mer＇s disease. The generation and deposition of amyloid-beta is one of the crucial factors for the onset and progression of Alzheimer＇s disease. Lipid rafts are glycolipid-rich liquid domains of the plasma membrane, where certain types of protein tend to aggregate and intercalate. Lipid rafts are involved in the generation of amyloid-beta oligomers and the formation of amyloid-beta peptides. In this paper, we review the mechanism by which lipid rafts disturb the aberrant deg- radative autophagic-lysosomal pathway of amyloid-beta, which plays an important role in the pathological process of Alzheimer＇s disease. Moreover, we describe this mechanism from the view of the Two-system Theory of fasciology and thus, suggest that lipid rafts may be a new target of Alzheimer＇s disease treatment.展开更多
Benign prostatic hyperplasia(BPH)is a pathologic condition of the prostate described as a substantial increase in its number of epithelial and stromal cells.BPH may significantly reduce the quality of life due to the ...Benign prostatic hyperplasia(BPH)is a pathologic condition of the prostate described as a substantial increase in its number of epithelial and stromal cells.BPH may significantly reduce the quality of life due to the initiation of bladder outlet obstruction and lower urinary tract syndromes.Current medical therapies mostly consist of inhibitors of 5α-reductase orα1-adrenergic blockers;their efficacy is often insufficient.Antagonistic analogs of neuropeptide hormones are novel candidates for the management of BPH.At first,antagonists of luteinizing hormone-releasing hormone(LHRH)have been introduced to the therapy aimed to reduce serum testosterone levels.However,they have also been found to produce an inhibitory activity on local LHRH receptors in the prostate as well as impotence and other related side effects.Since then,several preclinical and clinical studies reported the favorable effects of LHRH antagonists in BPH.In contrast,antagonists of growth hormone-releasing hormone(GHRH)and gastrin-releasing peptide(GRP)have been tested only in preclinical settings and produce significant reduction in prostate size in experimental models of BPH.They act at least in part,by blocking the action of respective ligands produced locally on prostates through their respective receptors in the prostate,and by inhibition of autocrine insulin-like growth factors-Ⅰ/Ⅱand epidermal growth factor production.GHRH and LHRH antagonists were also tested in combination resulting in a cumulative effect that was greater than that of each alone.This article will review the numerous studies that demonstrate the beneficial effects of antagonistic analogs of LHRH,GHRH and GRP in BPH,as well as suggesting a potential role for somatostatin analogs in experimental therapies.展开更多
The pathological implication of amyloid precursor protein(APP)in Alzheimer’s disease has been widely documented due to its involvement in the generation of amyloid-β peptide.However,the physiological functions of AP...The pathological implication of amyloid precursor protein(APP)in Alzheimer’s disease has been widely documented due to its involvement in the generation of amyloid-β peptide.However,the physiological functions of APP are still poorly understood.APP is considered a multimodal protein due to its role in a wide variety of processes,both in the embryo and in the adult brain.Specifically,APP seems to play a key role in the proliferation,differentiation and maturation of neural stem cells.In addition,APP can be processed through two canonical processing pathways,generating different functionally active fragments:soluble APP-α,soluble APP-β,amyloid-β peptide and the APP intracellular C-terminal domain.These fragments also appear to modulate various functions in neural stem cells,including the processes of proliferation,neurogenesis,gliogenesis or cell death.However,the molecular mechanisms involved in these effects are still unclear.In this review,we summarize the physiological functions of APP and its main proteolytic derivatives in neural stem cells,as well as the possible signaling pathways that could be implicated in these effects.The knowledge of these functions and signaling pathways involved in the onset or during the development of Alzheimer’s disease is essential to advance the understanding of the pathogenesis of Alzheimer’s disease,and in the search for potential therapeutic targets.展开更多
Chilled chicken has become the mainstream of chicken consumption.In order to explore the effect of post-mortem aging on water-soluble flavor precursors of chicken,pH,adenosine triphosphate(ATP)degradation,flavor nucle...Chilled chicken has become the mainstream of chicken consumption.In order to explore the effect of post-mortem aging on water-soluble flavor precursors of chicken,pH,adenosine triphosphate(ATP)degradation,flavor nucleosides,free amino acids and water-soluble low molecular weight peptides were determined using Qingyuan partridge yellow-feathered broilers as material during 0-4℃ post-mortem aging in 48 h.The results showed that the pH value fell to the limit pH 5.64(4 h)in chicken breast and 6.21(3 h)in thigh.Regardless of chicken breast or thigh,ATP dropped rapidly within 3 h.It was found that the K-value in chicken thigh was the lowest at 2 h indicating the freshness was the best.Considering the equivalent umami concentration(EUC),the value at 3 h and 4 h was relatively high,but the corresponding electronic tongue umami value was not high,which further showed that the water-soluble low molecular taste peptide played an important role on the post-mortem aging process.Combined with cluster analysis and partial least squares discriminant analysis(PLS-DA),it was preliminarily inferred that the optimal time for chilled chicken during 0-4℃ post-mortem aging was 2 h,which could provide a theoretical basis for the further processing of fresh chicken.展开更多
The aim of this study is to find the experimental evidence that the precursor frequency of alloreactive CTLs is proportional to the number of the T-cell epitope specificities. The number of T-cell epitope specificitie...The aim of this study is to find the experimental evidence that the precursor frequency of alloreactive CTLs is proportional to the number of the T-cell epitope specificities. The number of T-cell epitope specificities was manipulated by pulsing different humor of HLA-A2 restricted peptide（s） onto the T2 cells, which acted as stimulating cells to elicit allo-reaction by co-culturing with peripheral blood lymphocytes （PBLs） of HLA-A2 negative individual. Ten HLA-A2 restricted peptides （all were normal cell components ） were synthesized, and cell peptide extract was prepared by frozen and thawed. T2 cells loaded with different number of peptide（s） were co-cultured with PBLs of an HLA-A2 negative individual; the latter were stained with PKH67 in advance. Then the proliferation was monitored with flow cytometry, and the precursor frequency of the effector cells was ＇analyzed by the ModFit Software. After 6 d of culture, no proliferation was observed in the bulk culture of PBL alone, and obvious proliferation took place when PBLs of the HLA-A2 negative were co-cultured with T2 cells loaded with or without loading peptide（ s）. The precursor frequency of the alloreactive CTLs was 0.052 819 for co-culture with T2 cells loaded without peptide; however it was 0. 030 429 for T2 cells with EBV/LMP2A and 0. 030 528 for T2 cells loaded with a single autogeneic peptide, and increased up to 0. 144 942 for T2 cells loaded with 10 autogeneic peptides; the precursor frequency was 0. 203 649 when co-cultured with T2 cells loaded with miscellaneous peptides extracted from the cytoplasm of T2 cells. This study reveals that the precursor frequency of alloreactive CTLs is proportional to the number of T-cell epitope specificities, and independent of the density of the allogeneic HLA Class Ⅰ molecule. Our findings support the hypothesis that the alloreactive T cell populations comprise miscellaneous T cell clones; each is specific to corresponding pMHC. The novel constellation of peptides presented by allogeneic MHC molecules makes thousands of different epitopes, which account for the exceptional high precursor frequency of alloreactive T cells.展开更多
基金Supported by National Natural Science Foundation of China(31802149)China Postdoctoral Science(2019M651985)+2 种基金Natural Science Foundation of Jiangsu Province(BK20180919)Scientific Research Fund of Nanjing General Hospital of Nanjing Military Command(2016033)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘[Objectives]This study was conducted to obtain porcine gastrin-releasing peptide(GRP)fusion protein.[Methods]The constructed pET32a(+)-GRP plasmid was transformed into Escherichia coli BL21(DE3)competent cells to obtain the pET32a(+)-GRP-BL21(DE3)fusion protein expression strain,which was induced with 0.5 mM IPTG at 25℃and 150 r/min for 12 h,and the His-tagged GRP fusion protein was detected by SDS-Page gel electrophoresis and Western Blot.[Results]After optimizing the IPTG-induced expression conditions,it was confirmed that the porcine GRP fusion protein was obtained,and the porcine GRP fusion protein was soluble,stable and highly active.[Conclusions]This study lays a foundation for the subsequent preparation of anti-pig GRP antibodies.
基金supported by Ministry of Science and Technology of China(No.2012YQ090194 and No.2013AA102204)the National Natural Science Foundation of China(No.21676191,No.21476165,and No.21621004)
文摘Recently, enzymatic peptide synthesis has drawn increasing attention due to its eco-friendly reagents and mild conditions, as compared to traditional chemical peptide synthesis. In this study, we successfully produced an important antioxidant dipeptide precursor, BOC-Tyr-Ala, via a kinetically controlled enzymatic peptide synthesis reaction, catalyzed by the recombinant car- boxypeptidase Y （CPY） expressed in P. pastoris GS 115. In this reaction, the enzyme activity was 95.043 U/mL, and we used t-butyloxycarbonyl-L-tyrosine-methyl ester （BOC-Tyr-OMe） as the acyl donor and L-alanine （L-Ala） was the amino donor. We optimized the reaction conditions to be： 30 ℃, pH 9.5, organic phase （methanol）/aqueous phase = 1：20, BOC-Tyr-OMe 0.05 mol/L, Ala 0.5 mol/L, and a reaction time of 12 h. Under these conditions, the dipeptide yield reached 49.84%. Then, we established the kinetic model of the synthesis reaction in the form of Michaelis-Menten equation according to the con-centration-time curve during the process and the transpeptidation mechanism. We calculated the apparent Michaelis constant K^（app）mand the apparent maximum reaction rate r^（app）max to be 2.9946 x 10^-2 mol/L and 2.0406 x 10.2 mmol/（mL h）, respectively.
基金supported by a grant from Projects of High-tech Industrialization of Guangdong Province of China,No.2011B010500004a grant from National Financial Major Project of China
文摘Amyloid-beta peptide is the main component of amyloid plaques, which are found in Alzhei- mer＇s disease. The generation and deposition of amyloid-beta is one of the crucial factors for the onset and progression of Alzheimer＇s disease. Lipid rafts are glycolipid-rich liquid domains of the plasma membrane, where certain types of protein tend to aggregate and intercalate. Lipid rafts are involved in the generation of amyloid-beta oligomers and the formation of amyloid-beta peptides. In this paper, we review the mechanism by which lipid rafts disturb the aberrant deg- radative autophagic-lysosomal pathway of amyloid-beta, which plays an important role in the pathological process of Alzheimer＇s disease. Moreover, we describe this mechanism from the view of the Two-system Theory of fasciology and thus, suggest that lipid rafts may be a new target of Alzheimer＇s disease treatment.
基金Supported by The Medical Research Service of the Veterans Affairs Department,Departments of Pathology and Medicine,Division of Hematology/Oncology,Sylvester Comprehensive Cancer Center,University of Miami,Miller School of Medicine,the South Florida Veterans Affairs Foundation for Research and Education(all to Schally AV)the L Austin Weeks Endowment for Urologic Research(to Block NL)+2 种基金in part by a grant from the Urology Care Foundation Research Scholars Program and the American Urological Association(AUA)Southeastern Section(to Rick FG)by a stipend program of the Department of Medicine,Dresdenby the Helmholtz Alliance ICEMED(Imaging and Curing Environmental Metabolic Diseases)through the Initiative and Networking Fund of the Helmholtz Association(to Popovics P)
文摘Benign prostatic hyperplasia(BPH)is a pathologic condition of the prostate described as a substantial increase in its number of epithelial and stromal cells.BPH may significantly reduce the quality of life due to the initiation of bladder outlet obstruction and lower urinary tract syndromes.Current medical therapies mostly consist of inhibitors of 5α-reductase orα1-adrenergic blockers;their efficacy is often insufficient.Antagonistic analogs of neuropeptide hormones are novel candidates for the management of BPH.At first,antagonists of luteinizing hormone-releasing hormone(LHRH)have been introduced to the therapy aimed to reduce serum testosterone levels.However,they have also been found to produce an inhibitory activity on local LHRH receptors in the prostate as well as impotence and other related side effects.Since then,several preclinical and clinical studies reported the favorable effects of LHRH antagonists in BPH.In contrast,antagonists of growth hormone-releasing hormone(GHRH)and gastrin-releasing peptide(GRP)have been tested only in preclinical settings and produce significant reduction in prostate size in experimental models of BPH.They act at least in part,by blocking the action of respective ligands produced locally on prostates through their respective receptors in the prostate,and by inhibition of autocrine insulin-like growth factors-Ⅰ/Ⅱand epidermal growth factor production.GHRH and LHRH antagonists were also tested in combination resulting in a cumulative effect that was greater than that of each alone.This article will review the numerous studies that demonstrate the beneficial effects of antagonistic analogs of LHRH,GHRH and GRP in BPH,as well as suggesting a potential role for somatostatin analogs in experimental therapies.
基金supported by grants from the Ministerio de Ciencia e Innovación-Instituto de Salud Carlos Ⅲ(PI-10/00291 and MPY1412/09)Ministerio de Economía y Competitividad(SAF2015-71140-R)+2 种基金Comunidad de Madrid(Neurostem-Comunidad de Madrid consortium S2010/BMD-2336)supported by grants from Plan de Empleo Juvenil-Ministerio de Economía y Competitividad
文摘The pathological implication of amyloid precursor protein(APP)in Alzheimer’s disease has been widely documented due to its involvement in the generation of amyloid-β peptide.However,the physiological functions of APP are still poorly understood.APP is considered a multimodal protein due to its role in a wide variety of processes,both in the embryo and in the adult brain.Specifically,APP seems to play a key role in the proliferation,differentiation and maturation of neural stem cells.In addition,APP can be processed through two canonical processing pathways,generating different functionally active fragments:soluble APP-α,soluble APP-β,amyloid-β peptide and the APP intracellular C-terminal domain.These fragments also appear to modulate various functions in neural stem cells,including the processes of proliferation,neurogenesis,gliogenesis or cell death.However,the molecular mechanisms involved in these effects are still unclear.In this review,we summarize the physiological functions of APP and its main proteolytic derivatives in neural stem cells,as well as the possible signaling pathways that could be implicated in these effects.The knowledge of these functions and signaling pathways involved in the onset or during the development of Alzheimer’s disease is essential to advance the understanding of the pathogenesis of Alzheimer’s disease,and in the search for potential therapeutic targets.
基金supported by China Agriculture Research System of MOF and MARA (CARS-41)Wens Fifth Five R&D Major Project (WENS-2020-1-ZDZX-007)
文摘Chilled chicken has become the mainstream of chicken consumption.In order to explore the effect of post-mortem aging on water-soluble flavor precursors of chicken,pH,adenosine triphosphate(ATP)degradation,flavor nucleosides,free amino acids and water-soluble low molecular weight peptides were determined using Qingyuan partridge yellow-feathered broilers as material during 0-4℃ post-mortem aging in 48 h.The results showed that the pH value fell to the limit pH 5.64(4 h)in chicken breast and 6.21(3 h)in thigh.Regardless of chicken breast or thigh,ATP dropped rapidly within 3 h.It was found that the K-value in chicken thigh was the lowest at 2 h indicating the freshness was the best.Considering the equivalent umami concentration(EUC),the value at 3 h and 4 h was relatively high,but the corresponding electronic tongue umami value was not high,which further showed that the water-soluble low molecular taste peptide played an important role on the post-mortem aging process.Combined with cluster analysis and partial least squares discriminant analysis(PLS-DA),it was preliminarily inferred that the optimal time for chilled chicken during 0-4℃ post-mortem aging was 2 h,which could provide a theoretical basis for the further processing of fresh chicken.
基金The work was supported by the grants from the National Natural Science Foundation of China(No.30271201)the Major State Basic Research Development Program of China(No.2001C510008).
文摘The aim of this study is to find the experimental evidence that the precursor frequency of alloreactive CTLs is proportional to the number of the T-cell epitope specificities. The number of T-cell epitope specificities was manipulated by pulsing different humor of HLA-A2 restricted peptide（s） onto the T2 cells, which acted as stimulating cells to elicit allo-reaction by co-culturing with peripheral blood lymphocytes （PBLs） of HLA-A2 negative individual. Ten HLA-A2 restricted peptides （all were normal cell components ） were synthesized, and cell peptide extract was prepared by frozen and thawed. T2 cells loaded with different number of peptide（s） were co-cultured with PBLs of an HLA-A2 negative individual; the latter were stained with PKH67 in advance. Then the proliferation was monitored with flow cytometry, and the precursor frequency of the effector cells was ＇analyzed by the ModFit Software. After 6 d of culture, no proliferation was observed in the bulk culture of PBL alone, and obvious proliferation took place when PBLs of the HLA-A2 negative were co-cultured with T2 cells loaded with or without loading peptide（ s）. The precursor frequency of the alloreactive CTLs was 0.052 819 for co-culture with T2 cells loaded without peptide; however it was 0. 030 429 for T2 cells with EBV/LMP2A and 0. 030 528 for T2 cells loaded with a single autogeneic peptide, and increased up to 0. 144 942 for T2 cells loaded with 10 autogeneic peptides; the precursor frequency was 0. 203 649 when co-cultured with T2 cells loaded with miscellaneous peptides extracted from the cytoplasm of T2 cells. This study reveals that the precursor frequency of alloreactive CTLs is proportional to the number of T-cell epitope specificities, and independent of the density of the allogeneic HLA Class Ⅰ molecule. Our findings support the hypothesis that the alloreactive T cell populations comprise miscellaneous T cell clones; each is specific to corresponding pMHC. The novel constellation of peptides presented by allogeneic MHC molecules makes thousands of different epitopes, which account for the exceptional high precursor frequency of alloreactive T cells.
