Effects of folic acid and vitamin B12 on human umbilical vein endothelial cells against homocysteine-induced apoptosis

AIM: To investigate the effect of folic acid and vitamin B₁₂ on homocysteine (Hcy)-induced apoptosis of human umbilical vein endothelial cells (HUVECs) through mammalian sterile 20-like kinase 1 (MST1). ME-THODS: HUVECs were cultured in the absence (control group), or presence of 100 μmol/L Hcy alone (Hcy group) or 100 μmol/L Hcy plus 30 μmol/L folic acid and vitamin B₁₂ (intervention group) for 72 h. The effect of Hcy on the apoptosis of HUVECs was analyzed by flow cytometry. The transfection efficiency of DNA methyltransferase 1 (DNMT1)-overexpressing adenovirus was observed under fluorescence inverted microscope. The mRNA and the protein levels of DNMT1 and MST1 were determined by RT-qPCR and Western blot. The DNA methylation level of MST1 promoter was detected by methylation-specific PCR. RESULTS: Compared with control group, the apoptotic rate (P<0.01) and the expression of MST1 at mRNA (P<0.01) and protein (P<0.05) levels in the HUVECs were significantly increased, while the mRNA levels of DNMT1 was decreased in Hcy group (P<0.01). In addition, folic acid and vitamin B₁₂ treatment significantly inhibited Hcy-mediated apoptosis of HUVECs (P<0.01), increase in MST1 mRNA level (P<0.01) and decrease in DNMT1 mRNA level (P<0.01). Meantime, the mRNA level of MST1 was positively correlated with the apoptotic rate of the HUVECs (r=0.943 9, P<0.001). The expression of DNMT1 at mRNA and protein levels was significantly increased after the transfection of DNMT1-overexpressing adenovirus into HUVECs (P<0.01), and a large amount of green fluorescent protein expression was observed. Meanwhile, the DNA methylation level of MST1 promoter was increased (P<0.01), while the protein level of MST1 was decreased (P<0.01).CONCLUSION: Up-regulation of MST1 promotes Hcy-induced apoptosis of HUVECs, while folic acid and vitamin B₁₂ exert an anti-apoptosis effect, which might be regulated by hypermethylation of MST1 promoter region.     

基于MC9S12单片机的氢发动机电控系统设计

相比于传统燃料,氢能作为车用发动机燃料拥有众多的优越性,它被认为是最有发展前途的清洁代用燃料之一,为了实现对氢发动机的精确控制,设计了氢发动机电控系统,对喷氢正时和喷氢量进行了探讨,并采用模块化思想设计了氢发动机主程序和转速计算程序、A/D转换子程序以及输出比较中断程序.     

2种相手蟹线粒体12S rRNA基因序列分析

测定了红螯相手蟹和褶痕相手蟹线粒体12s rRNA基因部分片段的序列,前者为572 bp,后者为576 bp.二者的核苷酸序列A、T、G、C的含量相似,分别为42.5%、37.6%、11.9%、8.0%;42.0%、37.0%、12.5%、8.5%;不包括8处插入/缺失位点,两序列间有48个变异位点,核苷酸差异率为8.42%,其中转换30个、颠换18个,转换与颠换比约1.67.对国内外相手蟹长度为383 bp的12SrRNA基因同源序列进行分析,A T含量为76.6%～81.4%,明显高于G C的含量,且存有84个多态位点.系统发生树的拓扑结构显示,所有的相手蟹分别聚为3大支,代表着3个不同的属即相手蟹属、栉齿蟹属和仿相手蟹属;这与形态学分类结果相一致.     

ARID4B在牛磺酸调节成肌细胞C2C12蛋白质合成中的作用

肌肉细胞蛋白质合成能力与畜禽产肉量性状有关,试验旨在探究转录因子AT富集区4B(AT-rich interaction domain 4B,ARID4B)对牛磺酸(Taurine,Tau)调节成肌细胞C2C12蛋白质合成的影响.向体外培养C2C12细胞培养液中分别添加0、60、120、180和240μmol·L-1 T...     

玉米自交系K12的创造与应用

K12是以高配合力玉米自交系黄早四和西南亚热带种质为基础材料,创造性运用“品系内群体轮回选择与自交系谱法选择”选育而成的优良自交系。它具有配合力高,抗逆性强,适应性广,综合农艺性状好的特点,因而被全国各地广泛应用。自20世纪90年代以来,用K12组配选育并经省市以上品种审定委员会审定的品种就有10多个,累计推广种植面积467万hm2,为中国玉米育种和生产做出了巨大的贡献。     

利用种子蛋白聚丙烯酰胺凝胶电泳鉴定玉米种子纯度的研究

利用种子贮存蛋白SDS-PAGE技术,对2份玉米母本 种子的蛋白质进行电泳分析,结果表明,它们的母本种子蛋白质电泳图谱差异明显,特征谱带稳定。种子蛋白电泳鉴定与田间小区种植鉴定结果之间纯度达97;以上,该技术可作为玉米杂交种和自交系种子纯度鉴定的一种手段。     

利用花粉管通道法将叶片衰老抑制基因PSAG12-IPT导入普通小麦的研究

利用花粉管通道法将叶片衰老抑制基因PSAG12-IPT导入普通小麦品种西农1376,经PCR﹑GUS组织化学染色﹑点杂交和Southern杂交分析,证明带有特异启动子的目的基因已整合到5个植株的基因组中,且在大部分转基因植株中能够稳定遗传。通过叶片细胞分裂素含量﹑叶绿素含量﹑叶片衰老进程及农艺性状分析,初步证明PSAG12-IPT基因在     

寒地冬小麦TaEXPB12同源基因在拟南芥中的遗传转化及功能分析

扩展蛋白（Expansin）是一类具有非水解活性的细胞壁松弛蛋白,参与调控植物的生长发育和胁迫抗性。为探究寒地冬小麦扩展蛋白基因TaEXPB12-A/B/D的功能,本研究将克隆自高抗寒冬小麦品种东农冬麦2号的TaEXPB12-A/B/D三个基因转化到拟南芥中,利用抗性筛选、PCR和Western-blot鉴定,分别获得了过表达TaEXPB12-A/B/D三个基因的转基因拟南芥植株。进一步对转基因拟南芥的生长情况进行观察,并测定低温胁迫下转基因拟南芥的存活率、体内抗氧化酶活性以及丙二醛（MDA）、脯氨酸（Pro）、可溶性糖的含量。结果显示,过表达TaEXPB12-A/B/D三个基因可促进拟南芥根的伸长以及根毛和侧根的生长,且转基因拟南芥的叶宽、叶片数目、株高均显著高于野生型;低温处理后转基因拟南芥体内超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）的活性以及可溶性糖、Pro的含量均维持在较高水平,且MDA的含量较低。以上结果表明,TaEXPB12-A/B/D三个基因的过表达显著促进了转基因拟南芥的生长,并提高了转基因植株在低温胁迫下的存活率。     

Immunostimulatory effects of human recombinant interleukin-12 on peripheral blood mononuclear cells from normal dogs

Interleukin-12 (IL-12) plays a pivotal role in regulating cellular immune responses involving autoimmunity, infectious disease, and cancer. Human recombinant (hr) IL-12 is being evaluated for therapy of human cancer. We investigated the potential of hrIL-12 to activate canine peripheral blood mononuclear cells (PBMC) using proliferation and cytotoxicity as readouts. Human rIL-12 caused increased proliferation of PBMC, and enhanced lysis of allogeneic canine tumor targets mediated by PBMC from normal dogs in vitro. In addition, antibody-dependent cellular cytotoxicity (ADCC) mediated by canine PBMC was enhanced by hrIL-12. These results indicate that hrIL-12 is recognized by canine immune cells, triggering a number of immune responses in canine PBMC, that may be important for immunotherapy of canine cancer. Information from this investigation provides impetus for evaluation of the effects of hrIL-12 on PBMC from tumor-bearing dogs and should be helpful in the development of hrIL-12 as an immune cell activator in vivo in the dog.     

黄粉虫幼虫免疫血淋巴最佳制样条件的确定

采用正交设计Ｌ２７（３＾１３）的方法对大肠杆菌诱导黄粉幼虫的免疫血淋巴最佳制样条件进行了研究,结果表明：以每虫１０＾５菌量诱导较小的虫体后７２ｈ取样后得到的样品活性最高。