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Intracellular compartmentation of CTP synthase in Drosophila

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Journal of genetics and Genomics 2010年第5期37卷 281-296页

作者： Ji-Long Liu Medical Research Council Functional Genomics Unit,department of physiology,anatomy and genetics,university of oxford,oxford,OX1 3QX,United Kingdom Medical Research Council Functional Genomics Unit Department of Physiology Anatomy and Genetics University of Oxford Oxford OX1 3QX United Kingdom

Compartmentation is essential for the localization of biological processes within a eukaryotic cell. ATP synthase localizes to organelles such as mitochondria and chloroplasts. By contrast, little is known about the subcellular distribution of CTP synthase, the critical enzyme in the production of CTP, a high-energy molecule similar to ATP. Here I describe the identification of a novel intracellular structure con- taining CTP synthase, termed the cytoophidium, in Drosophila cells. I find that cytoophidia are present in all major cell types in the ovary and exist in a wide range of tissues such as brain, gut, trachea, testis, accessory gland, salivary gland and lymph gland. In addition, I find CTP synthase-containing cytoophidia in other fruit fly species. The observation of compartmentation of CTP synthase now permits a broad range of questions to be addressed concerning not only the structure and function of cytoophidia but also the organization and regulation of CTP synthesis.

关键词： CTP synthase cytoophidium Drosophila organelle cilium oogenesis

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Autoantibody against Cardiac β1-Adrenoceptor Induces Apoptosis in Cultured Neonatal Rat Cardiomyocytes

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Acta Biochimica et Biophysica Sinica 2006年第7期38卷 443-449页

作者： Yan GAO~1 Hui-Rong LIU~1 Rong-Rui ZHAO~1 Jian-Ming ZHI~(2*) 1 department of Cardiovascular physiology Shanxi Medical university,Taiyuan 030001,China 2 department of physiology,Shanghai Jiaotong university,College of Basic Medicine,Shanghai 200025,China department of Cardiovascular physiology Shanxi Medical UniversityTaiyuan 030001 China department of physiology Shanghai Jiaotong University College of Basic MedicineShanghai 200025 China

To clarify whether apoptosis is involved in the injury processes induced by autoantibodyagainst cardiac β1-adrenoceptor,we investigated the biological and apoptotic effects of antibodies on culturedneonatal rat *** rats were immunized with peptides corresponding to the second extra-cellular loop of the β1-adrenoceptor to induce the production of anti-β1-adrenoceptor antibodies in the ***（Ig）G in the sera was detected using synthetic antigen enzyme-linked immunosorbentassay and purified using the diethylaminoethyl cellulose ion exchange *** of cardiomyo-cytes was evaluated using agarose gel electrophoresis and flow *** results showed that thepositive serum IgG greatly increased the beating rates of cardiomyocytes and showed an"agonist-like"***,positive serum IgG induced cardiomyocyte apoptosis after treatment with β1-adrenoceptor overstimulation for *** effects of monoclonal antibody against β-adrenoceptor werealso found to be similar to those of positive serum *** was suggested that the autoantibody could inducecardiomyocyte apoptosis by excessive stimulation of β1-adrenoceptor.

关键词： β1-adrenoceptor rat cardiomyocyte autoantibody apoptosis

Diverse Effects of L-arginine on Cardiac Function of Rats Subjected to Myocardial Ischemia and Reperfusion in vivo

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Acta Biochimica et Biophysica Sinica 2007年第3期39卷 201-207页

作者： Xiaoliang WANG~1 Feng LIANG~2 Xiangying JIAOI Lei LIU~1 Xiaojie BAI~1 Meixia LI~1 Jianmin ZHI~3 Huirong LIU~1* 1 department of physiology,Shanxi Medical university,Taiyuan 030001,China 2 department of Cardiothoracic Surgery,General Hospital of Taiyuan Iron and Steel Company Taiyuan 030003,China 3 department of physiology.Shanghai Jiaotong university.College of Basic Medicine,Shanghai 200025,China department of physiology Shanxi Medical UniversityTaiyuan 030001 China department of Cardiothoracic Surgery General Hospital of Taiyuan Iron and Steel CompanyTaiyuan 030003 China department of physiology Shanghai Jiaotong University College of Basic MedicineShanghai 200025 China

In vivo administration of L-arginine at different time points during the course of myocardialischemia and reperfusion（MI/R）has been shown to differentially regulate postischemic *** is one of the most important indexes used to judge the degree of myocardial *** presentstudy attempted to determine whether in vivo administration of L-arginine at different stages of MI/R has adiverse influence on cardiac function of ischemic reperfused hearts and,if so,to investigate the *** adult rats were subjected to 30 min myocardial ischemia followed by 5 h *** L-arginine bolus was given either 10 min before and 50 min after reperfusion（early treatment）or3 h and 4 h after reperfusion（late treatment）.Early treatment with L-arginine markedly increased the leftventricular systolic pressure（LVSP）and dP/dtmax,and decreased myocardial nitrotyrosine *** strictcontrast,late treatment with L-arginine resulted in a significant decrease in LVSP and dP/dtmaxfrom 4 h to 5h after reperfusion,and increase in toxic peroxynitrite formation as measured by *** resultssuggest that the administration of L-arginine at different time points during the course of MI/R leads todiverse effects on cardiac *** supplementation decreased the nitrative stress and improvedleft ventricular ***,late treatment with L-arginine increased the formation of peroxynitriteand aggravated cardiac functional injury.

关键词： myocardial ischemia reperfusion cardiac function nitric oxide peroxynitrite

Effect of curcumin on multidrug resistance in resistant human gastric carcinoma cell line SGC7901/VCR

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Acta Pharmacologica Sinica 2005年第8期26卷 1009-1016页

作者： Xiao-qing TANG~1, Hu BI~1, Jian-qiang FENG~2, Jian-guo CAO~3 ~1 department of physiology, Nanhua university, Hengyang 421001, China ~2 department of physiology, Zhongshan Medical College, Sun Yat sen university, Guangzhou 510080, China ~3 Institute of Oncology, Nanhua university, Hengyang 421001, China department of physiology Nanhua University Hengyang China department of physiology Zhongshan Medical College Sun Yatsen University Guangzhou China Institute of Oncology Nanhua University Hengyang China

Aim: To investigate the reversal effects of curcumin on multidrug resistance （MDR） in a resistant human gastric carcinoma cell line. Methods: The cytotoxic effect of vincristine （VCR） was evaluated by MTT assay. The cell apoptosis induced by VCR was determined by propidium iodide （PI）-stained flow cytometry （FCM） and a morphological assay using acridine orange （AO）/ethidium bromide （EB） dual staining. P-glycoprotein （P-gp） function was demonstrated by the accumulation and efflux of rhodamine 123 （Rh123） using FCM. The expression of P-gp and the activation of caspase-3 were measured by FCM using fluorescein isothiocyanate （FITC）-conjugated anti-P-gp and anti-cleaved caspase-3 antibodies, respectively. Results: Curcumin, at concentrations of 5 μmol/L, 10 μmol/L, or 20 μmol/L, had no cytotoxic effect on a parent human gastric carcinoma cell line （SGC7901） or its VCR-resistant variant cell line （SGC7901/VCR）. The VCR-IC50value of the SGC7901/VCR cells was 45 times more than that of the SGC7901ceUs and the SGC7901/VCR cells showed apoptotic resistance to VCR. SGC7901/VCR cells treated with 5 μmol/L, 10μmol/L, or 20 μmol/L curcumin decreased the IC50value of VCR and promoted VCR-mediated apoptosis in a dose-dependent manner. Curcumin （10 μmol/L） increased Rh123 accumulation and inhibited the effiux of Rh123 in SGC7901/VCR cells, but did not change the accumulation and efflux of Rh123 in SGC7901 ceils. P-gp was overexpressed in SGC7901/VCR cells, whereas it was downregulated after a 24-h treatment with curcumin （10 μmol/L）. Resistant cells treated with 1 μmol/L VCR alone showed 77% lower levels of caspase-3 activation relative to SGC7901 cells, but the activation of caspase-3 in the resistant cell line increased by 44% when cells were treated with VCR in combination with curcumin. Conclusion: Curcumin can reverse the MDR of the human gastric carcinoma SGC7901/VCR cell line. This might be associated with decreased P-gp function and expression, and the promotion of caspase-3

关键词： curcumin multidrug resistance apoptosis P-glycoprotein caspase-3

changes in Autoantibodies against β1-Adrenoceptor and M2-Muscarinic Receptor during Development of Renovascular Hypertension in Rats

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Acta Biochimica et Biophysica Sinica 2004年第12期36卷 793-797页

作者： Jian-Ming ZHI*, Rong-Fang CHEN1, Heng WU2, Hui-Rong LIU2, and Rong-Rui ZHAO2 department of physiology, Shanghai Second Medical university, Shanghai 200025, China 1department of Toxicology, Second Military Medical university, Shanghai 200433, China 2 department of physiology, Shanxi Medical university, Taiyuan 030001, China department of physiology Shanghai Second Medical UniversityShanghai 200025 China department of Toxicology Second Military Medical UniversityShanghai 200433 China department of physiology Shanxi Medical UniversityTaiyuan 030001 China

In an experimental rat’s renovascular hypertension model, we studied the genesis of anti- cardiac β1-adrenoceptor and M2-muscarinic receptor autoantibodies in relation to the changes in immunological function during the development of renal hypertension. The biological activities of these autoantibodies were also examined. It was shown that after two weeks of operation both the frequency of occurrence and the titre of autoantibodies to cardiac β1-adrenoceptor and M2-muscarinic receptor were significantly increased as compared with the control of pre-treatment. The increased autoantibodies lasted for several weeks and then automatically decreased gradually to the pre-clipping level at 10 weeks. Meanwhile the ratio of CD4 /CD8 + + was also undergone an initial increase followed by gradual recovery and correlated well with the changes in antibody titre. The biological effects of these autoantibodies displayed an “agonistic-like” activities on the beating frequency of cultured neonatal cardiomyocyte. It is suggested that autoimmune mechanisms are involved in the pathogenesis of renal hypertension and the cardiac receptor autoantibodies might be one of the mechanisms leading to cardiac dysfunction.

关键词： autoantibody renal hypertension cardiac receptor immunology

Effects of AMP579 and adenosine on L-type Ca2+current in isolated rat ventricular myocytes

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Acta Pharmacologica Sinica 2005年第5期26卷 559-562页

作者： Xiong WANG~1,Bo-wei WU,Dong-mei WUdepartment of physiology Shanxi Medical university,Taiyuan 030001,China department of physiology Shanxi Medical University Taiyuan China

Aim:To compare the effects of AMP579 and adenosine on L-type Ca2+current(ICa-L)in rat ventricular myocytes and explore the mechanism by which AMP579acts on ***:ICaLwas recorded by patch-clamp technique in ***:Adenosine(10nmol/L to 50μmol/L)showed no effect onbasal ICaL,but it inhibited the ICaLinduced by isoproterenol 10 nmol/L in a concen-tration-dependent manner with the IC50of 13.06 μmol/*** to adenosine,AMP579 also showed an inhibitory effect on the ICaLinduced by ***579 and adenosine(both in 10 μmol/L)suppressed isoproterenol-inducedICaLby 11.1% and 5.2%, *** addition,AMP579 had a direct inhibitoryeffect on basal ICaLin a concentration-dependent manner with IC50(1.17 μmol/L).PD 116948(30μmol/L),an adenosine A1receptor blocker,showed no action on theinhibitory effect of AMP579 on basal ***,GF109203X(0.4μmol/L),aspecial protein kinase C(PKC)blocker,could abolish the inhibitory effect of AMP579on basal I*** the inhibitory effect of AMP579 on basal ICaLwas inducedthrough activating PKC,but not linked to adenosine ***:AMP579 shows a stronger inhibitory effect than adenosine on the ICaLinducedby ***579 also has a strong inhibitory effect on basal ICaLin ratventricular *** of PKC is involved in the inhibitory effect ofAMP579 on basal ICaLat downstream-mechanism.

关键词： AMP579 adenosine heart ventricles cardiac myocytes L-type calcium channels patch-clamp techniques

Double-stranded DNA breaks and gene functions in recombination and meiosis

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Cell Research 2006年第5期16卷 402-412页

作者： Wuxing Li~1 Hong Ma~1 ~1The department of Biology,The Intercollege Graduate Degree Program in Plant physiology,The Huck Institutes of the Life Sciences,The Pennsylvania State university,university Park,PA 16802,USA The department of Biology The Intercollege Graduate Degree Program in Plant Physiology The Huck Institutes of the Life Sciences The Pennsylvania State University University Park USA

Meiotic prophase Ⅰ is a long and complex *** recombination is an important process that occursbetween homologous chromosomes during meiotic prophase Ⅰ.Formation of chiasmata,which hold homologous chro-mosomes together until the metaphase Ⅰ to anaphase Ⅰ transition,is critical for proper chromosome *** have suggested that the SPO 11 proteins have conserved functions in a number of organisms in generating sites ofdouble-stranded DNA breaks (DSBs) that are thought to be the starting points of homologous *** these sites of DSBs requires the function of RecA homologs,such as RAD51,DMC 1,and others,as suggested bymutant studies;thus *** to repair these meiotic DSBs results in abnormal chromosomal alternations,leading todisrupted *** discoveries on the functions of these RecA homologs have improved the understanding of themechanisms underlying meiotic homologous recombination.

关键词： meiosis homologous recombination double-stranded DNA breaks SPO11 RAD51 DMC1

Isoprenaline enhances local Ca2+ release in cardiac myocytes

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Acta Pharmacologica Sinica 2006年第7期27卷 927-932页

作者： Jian-xin SHEN~(2,3,42 department of physiology,Shantou university Medical College,Shantou 515041,China 3 department of physiology,Medical School of Xi'an Jiaotong university,Xi'an 710061,China department of physiology Shantou University Medical College Shantou China department of physiology Medical School of Xi'an Jiaotong University Xi'an China

Aim:Contraction of cardiac myocytes is controlled by the generation and ampli-fication of intracellular Ca2+*** key step of this process is the couplingbetween sarcolemma L-type Ca2+channels（LCCs）and ryanodine receptors（RyRs）in the sarcoplasmic reticulum（SR）.β-Adrenergic stimulation is an important regu-latory mechanism for this coupling *** the details underlied the globallevel,which require local Ca2+release study are still *** present study isto explore the effects of β-adrenergic stimulation on local Ca2+***:Using confocal microscopy combined with loose-seal patch-clamp approaches,effects of isoprenaline(1 μmol·L-1),a β-adrenergic agonist,on local SR Ca2+re-lease triggered by Ca2+influx through LCCs in intact rat cardiac myocytes ***:Isoprenaline increased the intensity of ensemble averagedlocal Ca2+transients,the peak of which displayed a typical bell-shaped voltage-dependence over the membrane voltages ranging from～-40mV to～+35m ***-ther analysis showed that this enhancement could be explained by the increasedcoupling fidelity（which refers the increased probability of RyRs activation upondepolarization）,and the increased amplitude of evoked Ca2+sparks(due to moreCa2+releases through local RyRs).In addition,isoprenaline decreased the firstlatency,which displayed a typical"U"-shaped voltage-dependence,showing theavailable acceleration and synchronization of β-adrenergic stimulation on intrac-ellular calcium ***:Isoprenaline enhances local Ca2+release incardiac *** results underscore the importance of regulation of β-adrenergic stimulation on local intermolecular signals between LCCs and RyRs inheart cells.

关键词： local calcium release calcium signaling cardiac myocytes isoprenaline confocal microscopy

Melatonin reduces peroxynitrite-induced injury in aortic smooth muscle cells

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Acta Pharmacologica Sinica 2004年第2期25卷 60-64页

作者： Jun-lin ZHOU1, Xiao-guang ZHU1, Yi-ling LING2, Qing LI3 department of Hand Suegery, Third Affiliated Hospital, Hebei Medical university, Shijiazhuang 050051 2department of Pathophysiology, Hebei Medical university, Shijiazhuang 050017 3department of physiology, Hebei Medical university, Shijiazhuang 050017,China department of Hand Suegery Third Affiliated Hospital Hebei Medical University Shijiazhuang 050051 department of Pathophysiology Hebei Medical University Shijiazhuang 050017 department of physiology Hebei Medical University Shijiazhuang 050017

AIM: To study the protective role of melatonin (MT) in peroxynitrite-induced injury in cultured aortic smooth muscular cells (ASMC). METHODS: Peroxynitrite was synthesized chemically with a quenched flow reaction. Cells were exposed to peroxynitrite 500 μmol/L for 1 h in the absence or presence of various concentrations of MT 100, 300, and 500 μmol/L. Nitrotyrosine (NT), a specific “footprint” of peroxynitrite formation, was detected by immunohistochemical technique. The DNA damage was assayed by TUNEL technique. The levels of MDA in the medium and cell viability were measured. RESULTS: Incubation of ASMC with peroxynitrite 500 μmol/L for 1 h elicited the increase in the extent of immunostaining for NT, the rate of the TUNEL-positive cell, the content of MDA in the medium, and the number of dead cell. Pretreatment of ASMC with MT 100-500 μmol/L decreased these peroxynitrite-induced changes in a concentration-dependent manner. CONCLUSION: MT attenuated the injury induced by peroxynitrite in ASMC.

关键词： melatonin nitrates nitric oxide free radicals vascular smooth muscle