曲古抑菌素A对慢性髓细胞白血病细胞增殖与凋亡的作用及机制研究

该文研究了去乙酰化酶抑制剂曲古抑菌素A(trichostatin A,TSA)对慢性髓细胞白血病(chronic myeloid leukemia,CML)细胞株K562及K562/G01增殖和凋亡的影响及机制。采用不同浓度TSA处理K562及K562/G01细胞,CCK8和克隆形成实验检测细胞增殖能力;流式细胞术、蛋白印迹法和DAPI染色检测细胞凋亡;蛋白印迹法检测细胞自噬相关蛋白及BCR-ABL/STAT5/c-Myc信号轴蛋白水平。结果显示,TSA显著抑制K562及K562/G01细胞的增殖;明显促进K562及K562/G01细胞的凋亡;TSA与伊马替尼(imatinib,IM)联用可更有效地杀伤CML细胞。TSA可抑制BCR-ABL/STAT5/c-Myc信号轴,降低c-Myc蛋白水平;增强CML细胞自噬,自噬抑制剂氯喹(chloroquine,CQ)可部分回复TSA引起的凋亡。综上,TSA通过抑制STAT5信号通路,降低c-Myc蛋白水平,抑制CML细胞增殖;增强CML细胞自噬,促进其凋亡。     

敲低TRAF6对白血病K562细胞增殖和凋亡的影响及其分子机制

该文探讨了干扰肿瘤坏死因子受体相关因子6(tumor necrosis factor receptor-associated factor 6,TRAF6)表达对人白血病K562细胞增殖、凋亡的影响及其分子机制。将靶向TRAF6基因的sh RNA慢病毒载体感染K562细胞,利用荧光显微镜观察感染效率;Western blot方法检测TRAF6蛋白表达的改变;CCK-8法检测体外细胞增殖活性;流式细胞术分析细胞凋亡率;Western blot方法检测凋亡相关蛋白Bax、Bcl-2表达和AKT磷酸化水平的变化。结果显示,TRAF6-sh RNA慢病毒载体成功感染K562细胞,TRAF6蛋白表达水平明显下降。与空白对照组和TRAF6-NC组相比较,TRAF6-sh RNA组细胞增殖能力明显受抑(P0.05),而细胞凋亡率增加(P0.05);同时,促凋亡蛋白Bax表达升高、抗凋亡蛋白Bcl-2表达下降。此外,干扰TRAF6可下调K562细胞p-AKT(T308)和p-AKT(S473)活性,而总AKT水平未见明显变化。该研究表明,干扰TRAF6表达可抑制K562细胞增殖和诱导细胞凋亡,其机制可能与下调AKT活性有关,提示TRAF6可作为白血病治疗的一个潜在靶点。     

NPM1突变基因表达抑制K562白血病细胞体外增殖和侵袭

核仁磷酸蛋白(nucleophosmin,NPM1)突变是近年发现的在急性髓系白血病中发挥重要作用的基因改变,为探讨NPM1突变对K562白血病细胞体外增殖和侵袭能力的影响,将载体pEGFPC1-NPM1-mA转染K562细胞系,构建稳定表达NPM1突变蛋白的白血病细胞株(K562-mA)。利用细胞生长曲线观察细胞体外增殖能力;流式细胞仪检测细胞周期进程改变;细胞粘附、Transwell实验分别用以观察细胞体外粘附、迁移及侵袭能力。结果发现,NPM1突变转染后K562细胞体外增殖能力明显减弱;同时G1期细胞比例明显增高,S期细胞比例显著减低。与未处理组和空载体转染组细胞相比,K562-mA细胞体外迁移能力有所增加,但细胞粘附及侵袭能力却明显减弱。提示NPM1突变基因的表达能够抑制白血病细胞体外增殖和侵袭能力,为进一步深入探讨NPM1突变在白血病发生发展中的调控机制奠定了良好的基础。     

下调RALA表达抑制人白血病K562细胞迁移和侵袭

目的 研究小干扰RNA（siRNA）抑制v-ral 白血病致病因子RALA基因表达对人白血病K562细胞迁移和侵袭的影响.方法 利用LipofectamineTM 2000将化学合成的RALA siRNA转染体外培养的K562细胞,Real-time PCR检测细胞内RALA mRNA的表达水平;Western印迹检测细胞内RALA蛋白的表达水平;Boyden趋化小室实验检测细胞体外迁移和侵袭能力.结果与随机对照组相比,转染48 h后,RALA siRNA显著下调K562细胞内RALA mRNA和蛋白的表达（P＜0.05）.与随机对照组相比,转染RALA siRNA的K562细胞迁移和侵袭能力显著降低（P＜0.05）.结论 癌基因RALA在人白血病K562细胞迁移和侵袭过程中发挥重要作用,通过siRNA下调RALA的表达可抑制K562细胞迁移和侵袭能力.     

选择性COX-2抑制剂celecoxib对K562细胞的增殖抑制、凋亡诱导作用和分子机制

环氧化酶(cyclooxygenase, COX)家系被显示与恶性肿瘤的增殖和凋亡耐受有关,COX-2可作为恶性肿瘤治疗和预防的重要分子靶标.应用COX-2特异抑制剂——celecoxib,观察了药物对人慢性粒细胞白血病急变细胞株——K562细胞的增殖抑制和凋亡诱导效应.结果证明,celecoxib能够有效地抑制K562细胞增殖(台盼蓝染色,MTT试验及集落形成抑制试验证实),并呈一定的剂量依赖性.Celecoxib抑制K562细胞增殖的IC₅₀为46 μmol/L.通过DNA ladder胶电泳和流式细胞仪检测,凋亡细胞的AO/EB染色等方法证明celecoxib能够诱导K562细胞凋亡,这一效应与Caspase-3蛋白表达上调和裂解激活有关,当阻断Caspase-3的活性,celecoxib诱导的K562细胞凋亡明显受抑.利用RT-PCR分析技术及蛋白质印迹,证明K562细胞存在COX-2 mRNA和COX-2蛋白表达;而且,K562细胞COX-2蛋白表达可被IL-1β诱导性刺激,从而确认K562细胞为COX-2表达阳性细胞;celecoxib在较高浓度(80～160μmol/L)既可抑制K562细胞COX-2 mRNA表达,也可下调COX-2蛋白质表达,提示celecoxib抗K562白血病细胞活性与COX-2的抑制相关,其抗白血病的分子机制部分涉及到COX-2依赖性途径.     

氧化苦参碱对K562肿瘤细胞增殖的影响

目的:研究氧化苦参碱(OM)对人白血痛细胞系K562生长增殖的影响.方法:运用MTT比色法、活细胞计数法、集落形成法以及透射电镜观察检测OM对人白血病细胞系K562增殖抑制作用.结果:MTT实验、生长曲线及集落形成实验显示OM能明显抑制K562细胞的增殖.随着OM浓度的增加,K562细胞存活细胞显著降低,呈现明显的刺量依赖性,经相关分析,细胞抑制率与OM浓度呈正相关(r=0.9010),其半数抑制浓度(IC50)为0.33 mg/ml.透射电镜下显示在低浓度即有明显的诱导细胞凋亡的作用,出现核固缩、核碎裂、凋亡小体等典型的凋亡形态.结论:OM具有抑制K562白血病细胞增殖诱导肿瘤细胞凋亡的作用.     

lncRNA BANCR 在晶体上皮细胞上皮-间质转化，增殖、凋亡及自噬的作用

目的:探索长链非编码RNA BANCR(lncRNA BANCR)在人晶状体上皮细胞FHL24中对上皮-间质转化的作用,并进一步探究了其调控晶体上皮细胞增殖、凋亡及自噬的作用及相关分子机制。方法:运用qReal-time PCR检测TGF-β诱导对FHL24细胞内EMT相关标志物α-SMA,E-cadherin,Coll I,ZO1及BANCR m RNA相对表达量。细胞中转染BANCR。Western印迹检测各组细胞中EMT相关标志蛋白及LC3Ⅱ/Ⅰ的蛋白表达。MTT法检测各组细胞的增殖,凋亡情况。结果:与正常对照组比较,TGF-β诱导组细胞中BANCR,α-SMA, Coll I,ZO1 m RNA的相对表达量明显增加,而E-cadherin m RNA显著下降,差异均有统计学意义(t=-5.031,-7.145,-9.023,-6.012, 5.097均P0.05),以上因子的蛋白表达趋势相同,差异均有统计学意义(均P0.05)。si RNA-BANCR TGF-β诱导组细胞中E-cadherin m RNA相对表达量比si RNA TGF-β诱导组显著增加(t=-9.98, P0.05);α-SMA,Coll I及ZO1 m RNA相对表则显著减少(t=9.003; 27.738; 19.620, P0.05)。抑制BANCR后细胞增殖活力48、72 h时细胞活性显著降低(t=5.032, 9.041,均P0.05),细胞凋亡率显著升(t=16.772,P0.001)。自噬标志蛋白LC3-II/LC3-I比例增加(P 0.05)。结论:长链非编码BANCR参与了晶体上皮细胞的抑制其上皮-间质转化,抑制BANCR可抑制晶体上皮细胞增殖、增加凋亡及自噬的发生。     

RNAi干扰Shp2基因对K562细胞增殖的抑制效应

通过RNA干扰技术沉默蛋白酪氨酸磷酸酶跏2基因,构建重纽质粒,采用实时荧光定量PCR（Real-timePCR）法、Westernblot、MTT法、流式细胞术（FCM）分别检测转染后K562细胞中bcr／abl融合基因、bcr／abl融合蛋白的表达水平、细胞生长增殖变化及细胞凋亡率,探索该基因的沉默表达对K562N胞的抑制作用。结果表明,该实验成功构建出能明显下调Shp2基因及其蛋白表达的重组质粒,转染K562细胞后,其bcr／abl融合基因及融合蛋白水平均明显降低、K562细胞增殖活力被抑制（P〈0．05）、细胞凋亡水平上升（P〈0．05）。与对照组相比,其差异具有统计学意义。提示,重组质粒可显著降低bcr／abl基因及蛋白的表达,抑制K562细胞的生物学效应,表明在细胞水平沉默Shp2有可能成为治疗慢性粒细胞白血病的有效靶点。     

生长抑素对白血病细胞增殖影响的免疫组织化学研究

目的　研究生长抑素 (somatostatin ,SS)对人红白血病K5 6 2细胞和白血病患者骨髓单个核细胞 (BMM NC)增殖的影响。方法　将 8肽生长抑素 (奥曲肽 ,octreotide ,SMS)在体外作用于K5 6 2细胞和BMMNC ;用原位末端标记 (TUNEL)技术、免疫组织化学方法在光镜下随机计数阳性细胞数 ,并用图象分析系统分析bcl 2蛋白和CD34 抗原表达的光密度值 (OD值 )。结果　与对照组比较 ,用SMS 10 -6mol/L处理的K5 6 2细胞组TUNEL检测凋亡细胞明显增多(P <0 0 1)。在加SMS 10 -8mol/L～ 10 -6mol/L处理的白血病患者BMMNC组 ,bcl 2蛋白的表达与未加SMS组比较 ,阳性细胞数明显减少 (P <0 0 1) ;OD值P <0 0 1。CD34 抗原表达在SMS10 -6mol/L和 10 -7mol/L处理的白血病患者BMMNC组 ,阳性细胞数比与未处理组明显减少 (P <0 0 1) ;OD值明显低于对照组 ,分别为P <0 0 1和P <0 0 5。结论　SMS可抑制K5 6 2细胞和白血病患者BMMNC增殖 ,诱导凋亡 ;减少bcl 2蛋白和CD34 抗原的表达 ;SMS对白血病细胞具有抑制增殖的作用。     

过表达TRAF6对人急性髓系白血病细胞自噬活性的影响

该文旨在探讨过表达肿瘤坏死因子受体相关因子6(tumor necrosis factor receptorassociated factor 6,TRAF6)对人急性髓系白血病(acute myeloid leukemia,AML)细胞自噬活性的影响。利用基因表达数据库GEO分析TRAF6在AML患者白血病细胞中的mRNA表达水平。通过癌症基因组图谱TCGA分析TRAF6表达与AML患者临床预后的关系。将TRAF6重组质粒载体转染人AML细胞系(KG-1a和THP-1),采用自噬激活剂雷帕霉素(Rapamycin)和自噬相关抑制剂3-甲基腺嘌呤(3-methyladenine,3-MA)、巴弗洛霉素A1(bafilomycin A1,Baf-A1)分别处理AML细胞。荧光定量PCR、蛋白免疫印迹技术检测过表达TRAF6后白血病细胞自噬标志物(LC3和p62)mRNA和蛋白水平;免疫荧光方法检测LC3绿色荧光斑点结构(puncta);流式细胞术检测细胞凋亡率;CCK-8实验检测AML细胞的体外增殖能力。结果显示,AML患者白血病细胞高表达TRAF6(P<0.01);TRAF6高表达的白血病患者总体生存率和无事件生存率均较TRAF6低表达组显著降低(P=0.01)。TRAF6重组质粒转染能够显著增加两株AML细胞系中TRAF6的mRNA和蛋白水平(P<0.05)。Rapamycin处理能够激活AML细胞系自噬水平,过表达TRAF6后AML细胞LC3 mRNA和LC3II蛋白水平表达上调(P<0.05)、p62 mRNA和蛋白水平下调(P<0.05)以及LC3 puncta聚集增多。用Baf-A1处理以阻断过表达TRAF6的白血病细胞系中的自噬流后,LC3II蛋白表达水平显著提高(P<0.05)。3-MA处理过表达TRAF6的白血病细胞后,LC3II蛋白表达减少、p62蛋白表达增加(P<0.05)。此外,过表达TRAF6降低白血病细胞凋亡率和促进细胞的体外增殖(P<0.001),而过表达TRAF6后联合3-MA处理则可逆转TRAF6对白血病细胞的抗凋亡和促增殖作用(P<0.001)。以上研究结果提示,过表达TRAF6能够增强AML细胞的自噬活性,促进AML细胞的生长。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Kinetics and thermodynamics of peroxidase- and laccase-catalyzed oxidation of N-substituted phenothiazines and phenoxazines

N -substituted phenothiazines (PTs) and phenoxazines (POs) catalyzed by fungal Coprinus cinereus peroxidase and Polyporus pinsitus laccase were investigated at pH 4–10. In the case of peroxidase, an apparent bimolecular rate constant (expressed as k _cat/K _m) varied from 1 ×10⁷M⁻¹s⁻¹to 2.6×10⁸M⁻¹s⁻¹ at pH 7.0. The constants for PO oxidation were higher in comparison to PT. pH dependence revealed two or three ionizable groups with pK _a values of 4.9–5.7 and 7.7–9.7 that significantly affected the activity of peroxidase. Single-turnover experiments showed that the limiting step of PT oxidation was reduction of compound II and second-order rate constants were obtained which were consistent with the constants at steady-state conditions. Laccase-catalyzed PT and PO oxidation rates were lower; apparent bimolecular rate constants varied from 1.8×10⁵M⁻¹s⁻¹ to 2.0×10⁷M⁻¹s⁻¹ at pH 5.3. PO constants were higher in comparison to PT, as was the case with peroxidase. The dependence of the apparent bimolecular constants of compound II or copper type 1 reduction, in the case of peroxidase or laccase, respectively, was analyzed in the framework of the Marcus outer-sphere electron-transfer theory. Peroxidase-catalyzed reactions with PT, as well as PO, fitted the same hyperbolic dependence with a maximal oxidation rate of 1.6×10⁸M⁻¹s⁻¹ and a reorganization energy of 0.30 eV. The respective parameters for laccase were 5.0×10⁷M⁻¹s⁻¹ and 0.29 eV. Received: 20 September 1999 / Accepted: 24 February 2000     

Coiled-coil nanomechanics and uncoiling and unfolding of the superhelix and alpha-helices of myosin

The nanomechanical properties of the coiled-coils of myosin are fundamentally important in understanding muscle assembly and contraction. Force spectra of single molecules of double-headed myosin, single-headed myosin, and coiled-coil tail fragments were acquired with an atomic force microscope and displayed characteristic triphasic force-distance responses to stretch: a rise phase (R) and a plateau phase (P) and an exponential phase (E). The R and P phases arise mainly from the stretching of the coiled-coils, with the hinge region being the main contributor to the rise phase at low force. Only the E phase was analyzable by the worm-like chain model of polymer elasticity. Restrained molecular mechanics simulations on an existing x-ray structure of scallop S2 yielded force spectra with either two or three phases, depending on the mode of stretch. It revealed that coiled-coil chains separate completely near the end of the P phase and the stretching of the unfolded chains gives rise to the E phase. Extensive conformational searching yielded a P phase force near 40 pN that agreed well with the experimental value. We suggest that the flexible and elastic S2 region, particularly the hinge region, may undergo force-induced unfolding and extend reversibly during actomyosin powerstroke.     

放牧对牧草光合作用、呼吸作用和氮、碳吸收与转运的影响

研究放牧对草地植物生理活动的影响,对于揭示草地放牧演替的生理机制有重要意义.大量研究表明,家畜放牧对牧草光合作用、呼吸作用以及C和N吸收与转运的影响,可以分为生理伤害和生理恢复2个阶段.放牧通过改变草地冠层结构影响牧草光合作用,净光合作用速率短期内迅速下降,随着叶面积指数增加又逐渐上升,呼吸作用有相似的变化趋势.牧草放牧后再生长所需的C和N最初主要来自根系和留茬中的贮藏物质,此后随着牧草生长恢复逐渐由同化作用供给,C代谢与土壤N水平负相关.放牧后牧草生理活动变化与牧草遗传特性、种间竞争、家畜放牧特征、非生物环境等因素密切相关.     

Synthesis of hapten and conjugates of coumestrol and development of immunoassay

3-O-Carboxymethylcoumestrol was prepared as the hapten for immunoassay by a partial alkylation of coumestrol with ethyl chloroacetate in acetone alkalized with potassium carbonate. 3-O-Ethoxycarbonylmethylcoumestrol was separated by column chromatography and finally was hydrolyzed with formic acid. 1H and 13C NMR data (APT, COSY, HMQC, and HMBC) revealed that the reaction was regioselective, as 3-O-ethoxycarboxymethylcoumestrol was the only monosubstituted derivative. The hapten was then conjugated to bovine serum albumin and used for immunization of rabbits. A radioimmunoassay (RIA) system was established based on the polyclonal antiserum and a 125I-labeled hapten-tyrosine methyl ester conjugate as the radioligand. Parameters of the RIA: sensitivity: 12 pg per tube, 50% intercept: 140 pg per tube, working range: 20-4000 pg per tube. The cross-reactivity of a panel isoflavonoid and lignan phytoestrogens was either negligible (e.g. formononetin 0.07%; biochanin A 0.06%) or not detectable at all. The major immunoreactive peak in HPLC fractions from an alfalfa extract had the same retention time as coumestrol standard and represented 94.8% of the signal. The remaining 5.2% of immunoreactivity was distributed between five minor peaks. We conclude that after the validation for particular matrices, the method will be a useful tool for analysis of coumestrol, especially in low volume and low concentration samples.     

颧骨颧弓骨折的分类及诊治

颧骨颧弓骨折是最常见的面中部骨折之一,迄今为止,在其分类及诊治的选择上仍然存在一定争议,本文对目前颧骨颧弓骨折的分类及诊治的现状和进展作一综述,以期对临床工作提供参考。     

Effect of soil salinity and water stresses on growth and content of nitrogen,chloride and phosphate of wheat and triticale

Summary Three wheats and one triticale were grown, up to flowering stage, in pots on calcareous soil adjusted to a range of salinities (S₁=3.5, S₂=6, S₃=8.5, and S₄=11 mmhos/cm, 20°C, soilpaste extract) by adding solution consisting of 3∶2∶1 of Na-, Ca- and Mg chlorides in chemical equivalent amounts. Moisture in the pots was kept at 100% (W₁), 40% (W₂) and 20% (W₃) of the available water. The vegetative growth, nitrogen and phosphate were affected by S and W treatments, chloride was affected only by S. The interaction S×W affected only dry weight. Varietal effect was observed between wheat as a group and triticale. Multiple quadratic regression equations of these properties on salinity and water revealed that the higher the available water the wider the range of tolerable salinity. Triticale was relatively more tolerant to water stress. Salinity increases Cl and decreases N, whereas water stress enhances N accumulation to a certain extent. However, in triticale at S₃ and S₄ the effect of water stress on N was overshadowed by the excessive salinity. This did not occur for the wheat (Florence). P trends were described. R² for P was low (0.7435–0.3603) which made interpretations rather difficult.