Myocyte enhancer factor 2B （MEF2B） gene belongs to myocyte enhancer factor 2 （MEF2） gene family. They are all widely expressed in muscle and nerve tissues of human and animals. MEF2B plays an important role in the...Myocyte enhancer factor 2B （MEF2B） gene belongs to myocyte enhancer factor 2 （MEF2） gene family. They are all widely expressed in muscle and nerve tissues of human and animals. MEF2B plays an important role in the growth of muscle, development and differentiation of nerve system and liver fibrosis. This re- view mainly focused on the structural characteristics, tissue distribution, biological functions and research progress of MEF2B gene in human and animals.展开更多
IAPs (inhibitors of apoptosis) are a family of proteins containing one or more characteristic BIR domains. These proteins have multiple biological activities that include binding and inhibiting caspases, regulating ce...IAPs (inhibitors of apoptosis) are a family of proteins containing one or more characteristic BIR domains. These proteins have multiple biological activities that include binding and inhibiting caspases, regulating cell cycle progression, and modulating receptor-mediated signal transduction. Our recent studies found the IAP family members XIAP and c-IAP1 are ubiquitinated and degraded in proteasomes in response to apoptotic stimuli in T cells, and their degradation appears to be important for T cells to commit to death. In addition to three BIR domains, each of these IAPs also contains a RING finger domain.We found this region confers ubiquitin protease ligase (E3) activity to IAPs, and is responsible for the auto-ubiquitination and degradation of IAPs after an apoptotic stimulus. Given the factthat IAPs can bind a variety of proteins, such as caspases and TRAFs, it will be of interest to characterize potential substrates of the E3 activity of IAPs and the effects of ubiquitination byIAPs on signal transduction, cell cycle, and apoptosis.展开更多
AIM:To determine the changes of CD8+ T subsets especially CD8+CD28-T regulatory cells in rat model of experimental colitis induced by 2,4-dinitrofluorobenzene (DNFB). METHODS:The rat model of experimental colitis was ...AIM:To determine the changes of CD8+ T subsets especially CD8+CD28-T regulatory cells in rat model of experimental colitis induced by 2,4-dinitrofluorobenzene (DNFB). METHODS:The rat model of experimental colitis was induced by enema with DNFB.Ten days later,colonic intraepithelial and splenic lymphooltes were isolated from colitis animals (n=16) and controls (n=8).The proportion of CD8+ T cells,CD8+CD28+ T cells and CD8+CD28-T regulatory cells were determined by flow cytometry. RESULTS:The model of experimental colitis was successfully established by DNFB that was demonstrated by bloody diarrhea,weight loss and colonic histopathology.The proportion of CD8+ T cells in either splenic or colonic intraepithelial lymphocytes was not significantly different between colitis animals and controls (spleen:34.6±7.24 % vs 33.5±9.41%, colon:14.0±8.93 % vs 18.0±4.06 %,P>0.05).But CD8+CD28- T regulatory cells from colitis animals were significantly more than those from controls (spleen:11.3±2.26 % vs 5.64±1.01%, colon:6.50±5.37 % vs 1.07±0.65 %,P<0.05).In contrast, CD8+CD28+ T cells from colitis animals were less than those from controls (spleen:23.3±6.14 % vs 27.8±9.70 %,P=0.06; colon:7.52±4.18 % vs 16.9±4.07 %,P<0.05).The proportion of CD8+CD28-T regulatory cells in splenic and colon intraepithelial CD8+ T cells from colitis animals was higher than that from controls (spleen:33.3±5.49 % vs 18.4±7.26 %, colon:46.0±14.3 % vs6.10±3.72 %,P<0.005). CONCLUSION:Experimental colitis of rats can be induced by DNFB with simplicity and good reproducibility.The proportion of CD8+CD28-T regulatory cells in rats with experimental colitis is increased,which may be associated with the pathogenesis of colitis.展开更多
Objective.To in vestigate clinicopathologic characteristics and surgical results of nonfunctiona l islet cell tumors.Methods.We performed retrospective analysis of50patient s with nonfunctional islet cell tumor treat-...Objective.To in vestigate clinicopathologic characteristics and surgical results of nonfunctiona l islet cell tumors.Methods.We performed retrospective analysis of50patient s with nonfunctional islet cell tumor treat-ed at Peking Union Medical College Hospital from July1968to July1999,and summarized clinical symptoms and signs,primary diagnosis before surgery,surgical treatments,pathologic and im munohisto-logical characteristics.Results.Of the50cases examined from July 1968to July1999,12were found during physical examinations. The most common symptoms were upper abdominal pain and upper abdominal dis-com fort,which appeared in20casesand17casesrespectively,an d the most common sign was abdominal masses.B-ultrasound and CT are the most commonly used means for preoperative examination,with posit ive rates of97.8%and100%respectively.Op-e rative mortality was2%.Five-year survival rate of radical surgery of maligna nt cases was75%.Immuno-histological examinations showed that tumors rich i n multi-peptide linked hormones,neuron-specific eno-lase and chromaffin were in65%cases,90.6%and73.3% respectively.The positive rates of insulin,glucagons,somatostatin,pancreat ic polypeptide,gastrin and vasoactive intestinal peptide were68.2% ,51.2%,42.9%,40% ,25%and15.8%respectively.Conclusion.Nonfuncti onal islet cell tumors lack diagnostic specificity.Ultrasound and CT are primar y examination methods.Immunohistological analysis indicates different hormones ,but lacks the presence of related clinical symptoms.Surgery is an effective treatment for nonfunctional islet cell tumors,and even for those with distal m etastasis,immediate surgical removal and treatment can improve prognosis.展开更多
Intracellular Ca2+ is vital for cell physiology.Disruption of Ca2+ homeostasis contributes to human diseases such as heart failure,neuron-degeneration,and diabetes.To ensure an effective intracellular Ca2+ dynamics,va...Intracellular Ca2+ is vital for cell physiology.Disruption of Ca2+ homeostasis contributes to human diseases such as heart failure,neuron-degeneration,and diabetes.To ensure an effective intracellular Ca2+ dynamics,various Ca2+ transport proteins localized in different cellular regions have to work in coordination.The central role of mitochondrial Ca2+ transport mechanisms in responding to physiological Ca2+ pulses in cytosol is to take up Ca2+ for regulating energy production and shaping the amplitude and duration of Ca2+ transients in various micro-domains.Since the discovery that isolated mitochondria can take up large quantities of Ca2+ approximately 5 decades ago,extensive studies have been focused on the functional characterization and implication of ion channels that dictate Ca2+ transport across the inner mitochondrial membrane.The mitochondrial Ca2+ uptake sensitive to non-specific inhibitors ruthenium red and Ru360 has long been considered as the activity of mitochondrial Ca2+ uniporter(MCU) .The general consensus is that MCU is dominantly or exclusively responsible for the mitochondrial Ca2+ influx.Since multiple Ca2+ influx mechanisms(e.g.L-,T-,and N-type Ca2+ channel) have their unique functions in the plasma membrane,it is plausible that mitochondrial inner membrane has more than just MCU to decode complex intracellular Ca2+ signaling in various cell types.During the last decade,four molecular identities related to mitochondrial Ca2+ influx mechanisms have been identified.These are mitochondrial ryanodine receptor,mitochondrial uncoupling proteins,LETM1(Ca2+ /H+ exchanger) ,and MCU and its Ca2+ sensing regulatory subunit MICU1.Here,we briefly review recent progress in these and other reported mitochondrial Ca2+ influx pathways and their differences in kinetics,Ca2+ dependence,and pharmacological characteristics.Their potential physiological and pathological implications are also discussed.展开更多
Protein ubiquitination is an important post-translational modification(PTM) in eukaryotic organisms that regulates a variety of cellular processes, such as protein degradation, signal transduction, apoptosis, and DNA ...Protein ubiquitination is an important post-translational modification(PTM) in eukaryotic organisms that regulates a variety of cellular processes, such as protein degradation, signal transduction, apoptosis, and DNA damage tolerance. To decipher mechanistically the diverse biological functions of ubiquitination, homogeneous ubiquitinated proteins are greatly needed.Although direct isolation from cell source and in vitro enzymatic methods can be used to produce such proteins, these methods often suffer from problems of low yield or heterogeneous products. Comparably, total chemical and semisynthetic approaches offer good alternatives to produce the ubiquitinated proteins with high purity and selectivity. This review summarizes the recent developments of protein ubiquitination strategies and the use of the synthesized proteins to help garner structural and functional insight into the inner workings of the ubiquitin system.展开更多
Flow cytometry(FCM)is a powerful technique for single-bacteria analysis via simultaneous light-scattering and fluorescence measurements.By offering high-throughput,quantitative,and multiparameter analysis at the singl...Flow cytometry(FCM)is a powerful technique for single-bacteria analysis via simultaneous light-scattering and fluorescence measurements.By offering high-throughput,quantitative,and multiparameter analysis at the single-cell level,FCM has gained an increased popularity in microbiological research,food safety monitoring,water quality control,and clinical diagnosis.Here we will review the recent applications of flow cytometry in areas such as(1)total bacterial cell count,(2)bacterial viability analysis,(3)specific bacterial detection and identification,(4)characterization of physiological changes under environmental perturbations,and(5)biological function studies.Nevertheless,despite these widespread applications,challenges still remain for the detection of small sizes of bacteria and biochemical features that cannot be brightly stained via fluorescence.Recent improvement in FCM instrumentation will be discussed,and particularly the development of high sensitivity flow cytometry for advanced analysis of single bacterial cells will be highlighted.展开更多
There are different types of membrane proteins in a cellular membrane,and most of them must correctly assemble into appropriate clusters for their cellular functions.In this work,we suggest a physical mechanism for se...There are different types of membrane proteins in a cellular membrane,and most of them must correctly assemble into appropriate clusters for their cellular functions.In this work,we suggest a physical mechanism for selective aggregation of different membrane proteins without specific protein-protein attraction by dissipative particle dynamics method.A membrane-mediated interaction may result in different protein clusters with ideal mixing,nonideal mixing and demixing of different types of membrane proteins,depending on the extent of the similarity of membrane deformations by those proteins.展开更多
基金Supported by Financial Project from Ministry of Agriculture(2014-2130135)Specia Fund for Basal Scientific Research of Central Public-interest Scientific Institutes,Beijing Institute of Animal Husbandry and Veterinary,Chinese Academy of Agricultura Sciences(2014ywf-yb-7)~~
文摘Myocyte enhancer factor 2B （MEF2B） gene belongs to myocyte enhancer factor 2 （MEF2） gene family. They are all widely expressed in muscle and nerve tissues of human and animals. MEF2B plays an important role in the growth of muscle, development and differentiation of nerve system and liver fibrosis. This re- view mainly focused on the structural characteristics, tissue distribution, biological functions and research progress of MEF2B gene in human and animals.
文摘IAPs (inhibitors of apoptosis) are a family of proteins containing one or more characteristic BIR domains. These proteins have multiple biological activities that include binding and inhibiting caspases, regulating cell cycle progression, and modulating receptor-mediated signal transduction. Our recent studies found the IAP family members XIAP and c-IAP1 are ubiquitinated and degraded in proteasomes in response to apoptotic stimuli in T cells, and their degradation appears to be important for T cells to commit to death. In addition to three BIR domains, each of these IAPs also contains a RING finger domain.We found this region confers ubiquitin protease ligase (E3) activity to IAPs, and is responsible for the auto-ubiquitination and degradation of IAPs after an apoptotic stimulus. Given the factthat IAPs can bind a variety of proteins, such as caspases and TRAFs, it will be of interest to characterize potential substrates of the E3 activity of IAPs and the effects of ubiquitination byIAPs on signal transduction, cell cycle, and apoptosis.
基金the National Natural Science Foundation of China,No.30240051
文摘AIM:To determine the changes of CD8+ T subsets especially CD8+CD28-T regulatory cells in rat model of experimental colitis induced by 2,4-dinitrofluorobenzene (DNFB). METHODS:The rat model of experimental colitis was induced by enema with DNFB.Ten days later,colonic intraepithelial and splenic lymphooltes were isolated from colitis animals (n=16) and controls (n=8).The proportion of CD8+ T cells,CD8+CD28+ T cells and CD8+CD28-T regulatory cells were determined by flow cytometry. RESULTS:The model of experimental colitis was successfully established by DNFB that was demonstrated by bloody diarrhea,weight loss and colonic histopathology.The proportion of CD8+ T cells in either splenic or colonic intraepithelial lymphocytes was not significantly different between colitis animals and controls (spleen:34.6±7.24 % vs 33.5±9.41%, colon:14.0±8.93 % vs 18.0±4.06 %,P>0.05).But CD8+CD28- T regulatory cells from colitis animals were significantly more than those from controls (spleen:11.3±2.26 % vs 5.64±1.01%, colon:6.50±5.37 % vs 1.07±0.65 %,P<0.05).In contrast, CD8+CD28+ T cells from colitis animals were less than those from controls (spleen:23.3±6.14 % vs 27.8±9.70 %,P=0.06; colon:7.52±4.18 % vs 16.9±4.07 %,P<0.05).The proportion of CD8+CD28-T regulatory cells in splenic and colon intraepithelial CD8+ T cells from colitis animals was higher than that from controls (spleen:33.3±5.49 % vs 18.4±7.26 %, colon:46.0±14.3 % vs6.10±3.72 %,P<0.005). CONCLUSION:Experimental colitis of rats can be induced by DNFB with simplicity and good reproducibility.The proportion of CD8+CD28-T regulatory cells in rats with experimental colitis is increased,which may be associated with the pathogenesis of colitis.
文摘Objective.To in vestigate clinicopathologic characteristics and surgical results of nonfunctiona l islet cell tumors.Methods.We performed retrospective analysis of50patient s with nonfunctional islet cell tumor treat-ed at Peking Union Medical College Hospital from July1968to July1999,and summarized clinical symptoms and signs,primary diagnosis before surgery,surgical treatments,pathologic and im munohisto-logical characteristics.Results.Of the50cases examined from July 1968to July1999,12were found during physical examinations. The most common symptoms were upper abdominal pain and upper abdominal dis-com fort,which appeared in20casesand17casesrespectively,an d the most common sign was abdominal masses.B-ultrasound and CT are the most commonly used means for preoperative examination,with posit ive rates of97.8%and100%respectively.Op-e rative mortality was2%.Five-year survival rate of radical surgery of maligna nt cases was75%.Immuno-histological examinations showed that tumors rich i n multi-peptide linked hormones,neuron-specific eno-lase and chromaffin were in65%cases,90.6%and73.3% respectively.The positive rates of insulin,glucagons,somatostatin,pancreat ic polypeptide,gastrin and vasoactive intestinal peptide were68.2% ,51.2%,42.9%,40% ,25%and15.8%respectively.Conclusion.Nonfuncti onal islet cell tumors lack diagnostic specificity.Ultrasound and CT are primar y examination methods.Immunohistological analysis indicates different hormones ,but lacks the presence of related clinical symptoms.Surgery is an effective treatment for nonfunctional islet cell tumors,and even for those with distal m etastasis,immediate surgical removal and treatment can improve prognosis.
基金supported by NIH grants(Grant Nos.HL-033333 and HL093671)to Shey-Shing Sheu
文摘Intracellular Ca2+ is vital for cell physiology.Disruption of Ca2+ homeostasis contributes to human diseases such as heart failure,neuron-degeneration,and diabetes.To ensure an effective intracellular Ca2+ dynamics,various Ca2+ transport proteins localized in different cellular regions have to work in coordination.The central role of mitochondrial Ca2+ transport mechanisms in responding to physiological Ca2+ pulses in cytosol is to take up Ca2+ for regulating energy production and shaping the amplitude and duration of Ca2+ transients in various micro-domains.Since the discovery that isolated mitochondria can take up large quantities of Ca2+ approximately 5 decades ago,extensive studies have been focused on the functional characterization and implication of ion channels that dictate Ca2+ transport across the inner mitochondrial membrane.The mitochondrial Ca2+ uptake sensitive to non-specific inhibitors ruthenium red and Ru360 has long been considered as the activity of mitochondrial Ca2+ uniporter(MCU) .The general consensus is that MCU is dominantly or exclusively responsible for the mitochondrial Ca2+ influx.Since multiple Ca2+ influx mechanisms(e.g.L-,T-,and N-type Ca2+ channel) have their unique functions in the plasma membrane,it is plausible that mitochondrial inner membrane has more than just MCU to decode complex intracellular Ca2+ signaling in various cell types.During the last decade,four molecular identities related to mitochondrial Ca2+ influx mechanisms have been identified.These are mitochondrial ryanodine receptor,mitochondrial uncoupling proteins,LETM1(Ca2+ /H+ exchanger) ,and MCU and its Ca2+ sensing regulatory subunit MICU1.Here,we briefly review recent progress in these and other reported mitochondrial Ca2+ influx pathways and their differences in kinetics,Ca2+ dependence,and pharmacological characteristics.Their potential physiological and pathological implications are also discussed.
基金supported by Exploit Technologies Pte Ltd of Agency for Science,Technology and Research(A*Star)of Singapore(ETPL-QP-19-06)
文摘Protein ubiquitination is an important post-translational modification(PTM) in eukaryotic organisms that regulates a variety of cellular processes, such as protein degradation, signal transduction, apoptosis, and DNA damage tolerance. To decipher mechanistically the diverse biological functions of ubiquitination, homogeneous ubiquitinated proteins are greatly needed.Although direct isolation from cell source and in vitro enzymatic methods can be used to produce such proteins, these methods often suffer from problems of low yield or heterogeneous products. Comparably, total chemical and semisynthetic approaches offer good alternatives to produce the ubiquitinated proteins with high purity and selectivity. This review summarizes the recent developments of protein ubiquitination strategies and the use of the synthesized proteins to help garner structural and functional insight into the inner workings of the ubiquitin system.
基金the National Key Basic Research Program of China(2013CB933703)the National Natural Science Foundation of China(91313302,21105082,21225523,21472158,21027010,21521004)the Program for Changjiang Scholars and Innovative Research Team in University(IRT13036)
文摘Flow cytometry(FCM)is a powerful technique for single-bacteria analysis via simultaneous light-scattering and fluorescence measurements.By offering high-throughput,quantitative,and multiparameter analysis at the single-cell level,FCM has gained an increased popularity in microbiological research,food safety monitoring,water quality control,and clinical diagnosis.Here we will review the recent applications of flow cytometry in areas such as(1)total bacterial cell count,(2)bacterial viability analysis,(3)specific bacterial detection and identification,(4)characterization of physiological changes under environmental perturbations,and(5)biological function studies.Nevertheless,despite these widespread applications,challenges still remain for the detection of small sizes of bacteria and biochemical features that cannot be brightly stained via fluorescence.Recent improvement in FCM instrumentation will be discussed,and particularly the development of high sensitivity flow cytometry for advanced analysis of single bacterial cells will be highlighted.
基金supported by the National Natural Science Foundation of China(20736005,20876004)the support of the Research Foundation for Youth Scholars of Beijing Technology and Business Universitythe"Chemical Grid Project"of Beijing University of Chemical Technology for the generous allocations of computer time and excellent technical assistance
文摘There are different types of membrane proteins in a cellular membrane,and most of them must correctly assemble into appropriate clusters for their cellular functions.In this work,we suggest a physical mechanism for selective aggregation of different membrane proteins without specific protein-protein attraction by dissipative particle dynamics method.A membrane-mediated interaction may result in different protein clusters with ideal mixing,nonideal mixing and demixing of different types of membrane proteins,depending on the extent of the similarity of membrane deformations by those proteins.
