小鼠肌母细胞的增殖与分化

通过对小鼠肌母细胞C2C12的培养,研究C2C12细胞的增殖与分化的关系以及胰岛素在细胞分化过程中的作用。在对照组中,C2C12细胞增殖占了明显的优势,细胞形态几乎没有发生变化;而在实验组中,C2C12细胞在换为分化培养基24小时后,就出现了部分细胞衰亡和死亡的现象,尤其是在48小时细胞的死亡率达到最高,存活细胞开始从增殖期进入分化期,72小时出现了少量肌管,在96小时细胞分化效果达到最好。而在添加了胰岛素的分化培养基中的细胞分化效果明显好于没有添加胰岛素的分化培养基中的细胞,结果表明,胰岛素促进C2C12细胞的分化。     

呼肠病毒BYD株吸附蛋白σ1的原核表达及其抗原性鉴定

将呼肠病毒BYD株S1片段编码的细胞吸附蛋白基因连接至pET-28a( ),构建表达载体pET-28a( )-S1,转化表达宿主菌E.coli BL21(DE3),分析表达载体能否表达预期大小的重组σ1,并进一步鉴定重组σ1的抗原性。SDS-PAGE实验表明,经IPTG诱导后,表达载体能表达53kD左右蛋白质,与重组σ1的预期大小相符;免疫印迹分析表明重组σ1有较好的抗原性和特异性,可用于呼肠病毒诊断试剂的制备。     

刈割对草原化荒漠区驼绒藜(Krascheninnikovia ceratoides)根际土壤特性的影响

在休眠期对草原化荒漠中自然生长的驼绒藜(Krascheninnikovia ceratoides)进行不同频度的刈割处理(连年刈割、隔年刈割、对照),通过测定根际土壤理化性质、土壤微生物数量及土壤酶活性等指标,分析和讨论了不同频度的刈割处理对驼绒藜根际土壤特性的影响。结果表明:(1)连年刈割和隔年刈割都显著提高了根际土壤含水量,隔年刈割使根际土壤全碳含量显著上升、有机质含量显著下降,但刈割对根际土壤pH值和全氮含量的影响不明显;(2)刈割对根际土壤微生物总量的影响不明显,但显著影响细菌、真菌和放线菌的组成,连年刈割使真菌数量显著增加,隔年刈割使放线菌数量显著增加,驼绒藜根际土壤中放线菌所占比例最大,其数量表征了土壤的贫瘠程度;(3)刈割对根际土壤过氧化氢酶和中性磷酸酶活性有显著影响,两种刈割处理会显著提高土壤过氧化氢酶活性、降低土壤中性磷酸酶活性,而对土壤多酚氧化酶、脲酶、转化酶和碱性磷酸酶活性的影响不显著。总之,隔年刈割对植物根际土壤养分供给及土壤分解者的活性更加有利,而且土壤理化因子对土壤微生物数量和土壤酶活性的影响不显著。刈割对驼绒藜根际土壤特性影响的规律性不强,可能是由于半灌木刈割利用的时间较短,根际土壤各个测量指标之间尚未形成显著的相关性。     

Design,synthesis, and biological evaluation of novel carbazole derivatives as potent DNMT1 inhibitors with reasonable PK properties

The DNA methyltransferases (DNMTs) were found in mammals to maintain DNA methylation. Among them, DNMT1 was the first identified, and it is an attractive target for tumour chemotherapy. DC_05 and DC_517 have been reported in our previous work, which is non-nucleoside DNMT1 inhibitor with low micromolar IC₅₀ values and significant selectivity towards other S-adenosyl-_L-methionine (SAM)-dependent protein methyltransferases. In this study, through a process of similarity-based analog searching, a series of DNMT1 inhibitors were designed, synthesized, and evaluated as anticancer agents. SAR studies were conducted based on enzymatic assays. And most of the compounds showed strong inhibitory activity on human DNMT1, especially WK-23 displayed a good inhibitory effect on human DNMT1 with an IC₅₀ value of 5.0 µM. Importantly, the pharmacokinetic (PK) profile of WK-23 was obtained with quite satisfying oral bioavailability and elimination half-life. Taken together, WK-23 is worth developing as DNMT1-selective therapy for the treatment of malignant tumour.     

Hemin with Peroxidase Activity Can Inhibit the Oxidative Damage Induced by Ultraviolet A

Excessive reactive oxygen species (ROS), a highly reactive substance that contains oxygen, induced by ultraviolet A (UVA) cause oxidative damage to skin. We confirmed that hemin can catalyze the reaction of tyrosine (Tyr) and hydrogen peroxide (H₂O₂). Catalysis was found to effectively reduce or eliminate oxidative damage to cells induced by H₂O₂ or UVA. The scavenging effects of hemin for other free-radical ROS were also evaluated through pyrogallol autoxidation, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·)-scavenging assays, and phenanthroline–Fe²⁺ assays. The results show that a mixture of hemin and tyrosine exhibits strong scavenging activities for H₂O₂, superoxide anion (O₂⁻·), DPPH·, and the hydroxyl radical (·OH). Furthermore, the inhibition of oxidative damage to human skin keratinocyte (HaCaT) cells induced by H₂O₂ or UVA was evaluated. The results show that catalysis can significantly reduce the ratio of cell apoptosis and death and inhibit the release of lactate dehydrogenase (LDH), as well as accumulation of malondialdehyde (MDA). Furthermore, the resistance to apoptosis was found to be enhanced. These results show that the mixture of hemin and tyrosine has a significantly protective effect against oxidative damage to HaCaT cells caused by UVA, suggesting it as a protective agent for combating UVA damage.     

陕南茶树栽培区域生态与地方品种分布

陕南秦巴山区是亚热带北缘地区。由于生态环境复杂,地区差异性大,茶树栽培与引种受到一定限制。大致以汉江谷地粮作区为界,南部大巴山北麓低山丘陵区为适栽区;北部秦岭南麓低山丘陵区则为次适栽区。地方茶树群体品种有7个,约由28个地方品种组成,呈斑、块状分布。     

XBP-1转录激活系统的构建

人X盒结合蛋白1(XBP-1)是CREB／ATF(cAMP应答元件结合蛋白／激活转录因子)转录因子家族中的一员,在很多癌细胞中高水平表达。将XBP-1两种剪切形式的编码序列分别克隆在pRC-lac真核载体上,构建成pRC-lac-XBP-1S和pRC-lac-XBP-1U重组质粒。Westem印迹分析表明,这两种XBP-1形式在哺乳动物细胞中都得到了表达。瞬时转染人胚胎肾细胞293T,用荧光素酶报告基因检测这两种剪切形式的转录活性。结果显示,pRC-lac-XBP-1S和pRC-lac-XBP-1U在293T细胞中均有活性,pRC-lac-XBP-1U的活性约是空载体的65倍,pRC-lac-XBP-IS的活性约是空载体的3倍。成功构建了xBP-1的转录激活系统,为进一步了解XBp-1在各种疾病中的作用奠定了基础。     

电针诱导心肌缺血大鼠延髓头端腹外侧区nNOS和iNOS差异表达

许多研究表明,延髓头端腹外侧区(rostral ventrolateml medulla,RVLM)的NO/NOS系统参与心血管活动的中枢调节.本实验以结扎Wistar大鼠左冠状动脉前降支法建立急性心肌缺血(acute myocardial ischemia,AMI)动物模型,观察针刺"内关"穴改善AMI大鼠的心功能作用,同时检测大鼠RVLM区神经元型一氧化氮合酶(neuronal nitric oxide synthase,nNOS)和诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)表达的变化,进而探讨针刺治疗AMI的中枢机制.实验观察显示,AMI大鼠心功能各项指标减弱,伴随外周血去甲肾上腺素(norepinephrine,NE)和脑钠肽(brain natriuretic peptide,BNP)水平显著升高,同时RVLM区nNOS阳性神经元数和nNOS mRNA表达升高,而iNOS水平则降低.针刺"内关"穴(Pe 6)(每天30 min,连续5天)改善心功能,降低AMI大鼠血清中NE和BNP的水平,同时升高iNOS并降低nNOS在RVLM的表达.以上结果提示,针刺治疗心肌缺血的同时可以调节iNOS/NO和nNOS/NO在RVLM的变化,这可能与针刺通过调节RVLM区的NO含量进而降低交感传出,从而改善AMI大鼠的心功能有关.