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991.
本文在培养的大鼠三叉神经节(trigeminal ganglion,TG)神经元上采用全细胞膜片钳技术,探讨大麻素对大鼠TG神经元ATP激活电流(ATP-activated currents,IATP)的影响.结果显示(1)胞外给予ATP,大部分受检细胞(67/75,89.33%)可记录到一个内向电流,且具有剂量依赖性.该电流可被P2X嘌呤受体特异性拮抗剂PPADS所阻断.(2)预加WIN55212-2[大麻素受体1(cannabinoid receptor 1,CB1受体)激动剂]可对IATP产生抑制作用,此作用呈剂量依赖性,并可被CB1受体特异性拮抗剂AM281阻断.预加不同浓度的WIN55212-2(1x10-13、1x10-12、1x10-11、1x10-10、1x10-9和1x10-8mol/L)对IATP(1x10-4mol/L ATP)的抑制作用分别为(8.14±3.14)%、(20.11±2.72)%、(46.62±3.51)%、(72.16±5.64)%、(80.21±2.80)%和(80.59±3.55)%.(3)预加WIN55212-2后IATP的浓度-反应曲线明显下移;最大反应浓度时的IATP幅值减小了(58.02±4.21)%,而阈值基本不变;预加WIN55212.2前后曲线的EC50值非常接近(1.15x10-4mol/L vs 1.27x10-4 mol/L).(4)预加forskolin[腺苷酸环化酶(adenylyl cyclase,AC)激动剂]或8-Br-cAMP可以逆转WIN55212-2对IATP的抑制作用.以上结果表明,大麻素可能作用于CB1受体,通过抑制AC-cAMP-PKA途径发挥对IATP的抑制作用. 相似文献
992.
993.
The S2 domain of the severe acute respiratory syndrome coronavirus (SARS-CoV) spike (S) protein is responsible for fusion between virus and target cell membranes, and is expected to be immungenic. In this study, we investigated the immune responses against the S2 subunit in BALB/c mice, which were vaccinated either with plasmid DNA encoding the S2 domain (residues 681-1120), the recombinant S2 fragment (residues 681-980) in incomplete Freund's adjuvant, or with inactivated SARS-CoV. The increased number of specific cytotoxic cells (CTLs) and the high titer of specific antibody showed stimulation of both arms of the immune system in these groups. The shift in cytokines suggested that Th1-polarized immune response was induced by plasmid pCoVS2, meanwhile the Th2-dominant response was induced by recombinant S2 fragment and inactivated vaccine. However, the titer of neutralizing antibodies was only detectable in mice immunized with inactivated virus, but not with pCoVS2 plasmid. Taken together, the S2 domain could induce specific cellular immune response and a high level of total IgG but little neutralizing antibodies against infection by SARSCoV. 相似文献
994.
施肥进步在粮食增产中的贡献及其地理分异 总被引:15,自引:6,他引:15
采用中长期田间试验对8种模拟施肥模型在温带的海伦试验站、暖温带的沈阳试验站和亚热带的桃源试验站进行了6~10年试验,以比较、评价施肥在粮食生产中的贡献.结果发现,施肥在作物产量形成中的贡献随施肥制度和气候的热量因素所影响;在最佳施肥条件下,施肥在产量中的贡献率分别为海伦(温带)30%、沈阳(暖温带)38%、桃源(亚热带)44%.按这一实验结果可以一般地估计:当其他技术条件不变时,施肥在产量形成中的贡献率最高可达30~45%,随所在地区气候的热量条件而不同. 相似文献
995.
Ning-Sheng Lai Jian-Liang Chou Gary C. W. Chen Su-Qin Liu Ming-Chi Lu Michael W. Y. Chan 《Molecular biology reports》2014,41(6):3773-3780
In this study, we aim to determine the relationship between methylation level of an inflammatory-related gene, SOCS-1 in serum samples of patients with ankylosing spondylitis (AS) and their degree of inflammation as well as serum cytokine level. Quantitative real time methylation specific PCR was performed to examine the promoter methylation of SOCS-1 in serum samples of 43 HLA-B27+ AS patients and 6 B27+ healthy controls. Degree of inflammation was accessed by spondylopathy, sacroiliitis as well as acute phase reactant, erythrocyte sedimentation rate and C-reactive protein (CRP). Serum IL-6 and TNF-α level was determined by ELISA assay. SOCS-1 methylation can only be found in serums samples from patients but not normal control. Methylation of SOCS-1 significantly associated with severity of patient’s spondylopathy (P < 0.005), sacroiliitis (P < 0.005) and acute phase reactant CRP (P = 0.0278). AS patients also exhibited higher serum IL-6 (P < 0.001) and TNF-α level (P < 0.001). Importantly, patients with high serum IL-6 or TNF-α level demonstrated a significantly higher SOCS-1 methylation (P < 0.001). In conclusion, this proof-of-principle study suggested that methylation of SOCS-1 can be detected in serum of HLA-B27+ AS patients but not in B27+ controls. The pathogenic potential of SOCS-1 methylation in AS deserves further investigation. 相似文献
996.
Considering the practical technology-economy of glycerol processing from oleochemicals industry, the ensuing work was proposed to further explore the atmospheric aqueous glycerol autocatalytic organosolv pretreatment (AAGAOP) to improve the enzymatic hydrolysis of lignocellulosic biomass. With the liquid-solid ratio of 20 g g(-1) at 220 degrees C for 3h, the AAGAOP enabled wheat straw to remove approximately 70% hemicelluloses and approximately 65% lignin, with approximately 98% cellulose retention. The pretreated fiber was achieved with approximately 90% of the enzymatic hydrolysis yield after 48 h. At oven-drying, dehydration was likely to cause the hornification of fiber, which was responsible for the low enzymatic hydrolysis of dried fiber. With SEM observations, the AAGAOP disrupted wheat straw into thin and fine fibrils, with a small average size and more surface area. The AAGAOP technique, as a novel strategy, enhanced the enzymatic hydrolysis of lignocellulosic biomass by removing the chemically compositional barrier and altering the physically structural impediment. 相似文献
997.
998.
目的建立一种简单、有效的Balb/C乳鼠小脑Purkinje细胞原代培养方法,并初步研究其细胞电生理特性。方法钝性分离生后24h内的乳鼠小脑,采用低浓度胰蛋白酶加机械吹打法获得单细胞悬液,然后用含10%胎牛血清的DMEM/F12培养,24h候更换为1%N2+1%T3+1%谷氨酰胺的DMEM/F12维持培养,3-5d天后进行细胞免疫荧光染色,7-9d天后用全细胞膜片钳单通道法记录钙电流。结果该方法培养的神经元形态典型,细胞学鉴定阳性率高(70%),并能记录到钙通道电流。结论该方法取材容易,操作简便,且培养出的原代Purkinje细胞生长状态较好,神经元的活性较高,可用于电生理研究。 相似文献
999.
抑制O~6-甲基鸟嘌呤-DNA甲基转移酶活性与肿瘤细胞对亚硝脲药物敏感性关系的研究 总被引:1,自引:0,他引:1
80%以上的肿瘤细胞为O~6-甲基鸟嘌吟-DNA甲基转移酶(O~6-MT)活性较高的Mer~+型,能够修复亚硝脲药物(NU)造成的DNA烷化损伤,对NU不敏感。本实验证明,用0.75,0.50和0.25mmol/L甲基亚硝脲(MNU)分别处理Mer~+型的HeLaS3,SMMC-7721和表现Mer~-型特征的Cc801,均能明显降低细胞中O~6-MT活性,从而显著提高了三种细胞对嘧啶亚硝脲和双氯乙亚硝脲的敏感性,提示降低O~6-MT活性是使用NU对Mer~+型肿瘤进行有效治疗的前提。 相似文献
1000.
Infection of human dendritic cells by a sindbis virus replicon vector is determined by a single amino acid substitution in the E2 glycoprotein 总被引:5,自引:0,他引:5 下载免费PDF全文
Gardner JP Frolov I Perri S Ji Y MacKichan ML zur Megede J Chen M Belli BA Driver DA Sherrill S Greer CE Otten GR Barnett SW Liu MA Dubensky TW Polo JM 《Journal of virology》2000,74(24):11849-11857
The ability to target antigen-presenting cells with vectors encoding desired antigens holds the promise of potent prophylactic and therapeutic vaccines for infectious diseases and cancer. Toward this goal, we derived variants of the prototype alphavirus, Sindbis virus (SIN), with differential abilities to infect human dendritic cells. Cloning and sequencing of the SIN variant genomes revealed that the genetic determinant for human dendritic cell (DC) tropism mapped to a single amino acid substitution at residue 160 of the envelope glycoprotein E2. Packaging of SIN replicon vectors with the E2 glycoprotein from a DC-tropic variant conferred a similar ability to efficiently infect immature human DC, whereupon those DC were observed to undergo rapid activation and maturation. The SIN replicon particles infected skin-resident mouse DC in vivo, which subsequently migrated to the draining lymph nodes and upregulated cell surface expression of major histocompatibility complex and costimulatory molecules. Furthermore, SIN replicon particles encoding human immunodeficiency virus type 1 p55(Gag) elicited robust Gag-specific T-cell responses in vitro and in vivo, demonstrating that infected DC maintained their ability to process and present replicon-encoded antigen. Interestingly, human and mouse DC were differentially infected by selected SIN variants, suggesting differences in receptor expression between human and murine DC. Taken together, these data illustrate the tremendous potential of using a directed approach in generating alphavirus vaccine vectors that target and activate antigen-presenting cells, resulting in robust antigen-specific immune responses. 相似文献