Preparation of gfp-bcl-XL-contained recombinant adenovirus vector by the homologous recombination in bacteria

AIM: To prepare gfp-bcl-X_L-contained recombinant adenovirus(rAd-gfp-bcl-X_L).METHODS: Bcl-X_L gene was amplified from pEGFP-C₃-bcl-X_L, subcloned into shuttle plasmid and formed transfer plasmid of pAdTrack-CMV-bcl-X_L. Then pAdTrack-CMV-bcl-X_L was linealinzed with PmeI and co-transformed into BJ5183 bacteria with adenovirus genomic plasmid of pAdEasy-1. The identified recombinant adenovirus plasmid was digested with PacI and transfected into 293 cells to package recombinant adenovirus particles. The target gene was detected by PCR.RESULTS: There were about 35% positive recombinant bacterial clones after the co-transformation of pAdTrack-CMV-bcl-X_L and pAdEasy-1 into BJ5183. Recombinant adenovirus particle were produced and further amplified after the transfection of pAdEasy-1-gfp-bcl-X_L into 293 cells. PCR test indicated that the recombinant Ad contained bcl-X_L gene. The titer of the purified rAd-gfp-bcl-X_L was 6.5×10¹² PFU/L. CONCLUSIONS: The homologous recombination in bacteria is a convenient and high efficient method to prepare rAd-gfp-bcl-X_L. This affords a good gene transfer vector for the gene therapy in human’s diseases.     

Study on integrin-mediated albumin microbubbles adherence to activated leukocytes

AIM:To investigate the mechanism responsible for albumin microbubbles adherence to activated leukocytes. METHODS: In vitro studies were performed in which activated or nonactivated leukocytes were incubated with albumin microbubbles and observed under microscopy. The suspensions of leukocytes and microbubbles which contained or absented of integrins were analyzed with flow cytometry.RESULTS: A minimum of 50cells were identified under transillumination. 5 min after microbubbles were incubated with leukocytes, the number of cells interacting with microbubbles was greater for activated cells than for nonactivated cells(20.30±2.67 vs 4.50±1.43, P <0.01).Microbubbles attached to the surface of activated leukocytes were phagocytosed and remained intact for up to 30min. Microbubble attachment was inhibited notably by blocking the leukocyte β₂-integrin Mac-1(P <0.01) and by VLA-4mAb slightly(P <0.05) CONCLUSION: The mechanism of albumin microbubbles attaching to and phagocytosed by leukocytes was due to β₂-integrin and VLA-4 mediation. Phagocytosed microbubbles can remain at the regions of inflammation for15 min, also responsible to ultrasound.     

Changes of intracellular potassium activity and membrane potential in guinea pig ventricular myocardium during superfusion with low sodium solutions and effects of low pH

AIM:To investigate the changes in intracellular potassium activity(aⁱK) and membrane potential(V_m) induced by low external sodium infusion (Low [Na]_o) and to detect the mechanisms involved and the relationship between aⁱK and V_m. METHODS:aⁱK and V_m were measured in infusion with different sodium concentrations using methods of convenient and ion selective microelectrodes in guinea pig ventricular myocardium. RESULTS:Low [Na]_o resulted in a decrease in aⁱK and an increase in V_m in a Na⁺ concentration-dependent manner.At the same time,contraction and resting potential increased, and action potential duration decreased markedly,but action potential amplitude was not affected. A change of the pH from 7.4 to 7.0 in low [Na]_o solution reduced the decrease in aⁱK, but did not affect the increase in V_m.CONCLUSION:A better linear relationship appeared between the changes in aⁱk and [Na]_o or in V_m and [Na]_o,while during each low [Na]_o the change in both aⁱK or V_m may reach a new balance level.     

蔗渣滤泥培养料栽培平菇试验

以不同比例滤泥代替栽培料中的麦麸进行平菇栽培试验。结果表明 ,滤泥能替代栽培料中的麦麸。     

两系稻制种穗期病害发生较重的原因及防治措施

调查分析稻粒黑粉病、穗颈稻瘟等两系杂交稻制种穗期主要病害的发生原因,提出了清除菌源、轮换制种、健身栽培、对口药剂防治等防治措施。     

鸡腿蘑菌丝体的同工酶研究

用8种不同培养基配方，培养鸡腿蘑菌丝体，其同工酶分析结果表明，鸡腿蘑菌丝体酯酶(EST)同工酶谱差异明显，过氧化物酶(POD)同工酶谱差异明显。     

淡紫拟青霉菌料防治大豆胞囊线虫的后效研究

淡紫拟青霉不同菌株的培养菌料，施２２５ｋｇ／ｈｍ２，对大豆胞囊线虫不但当年有４５％～６９％的较好防效，而且第２年和第３年仍然有２２．５％～３７．７％和７．３％～２２．９％的后效，即空胞囊和被寄生的胞囊数量增加。     

奥芬达唑和阿苯达唑对猪囊尾蚴作用形态学比较观察

观察了奥芬达唑和阿苯达唑对猪体内及体外培养的不同发育阶段囊尾蚴作用的形态学效果.结果表明奥芬达唑具有显著的疗效,优于阿苯达唑,且对未成熟期猪囊尾蚴的杀灭作用优于成熟期.提示奥芬达唑可能成为抗未成熟期猪囊尾蚴及治疗脑囊虫病的有效药物.     

刚察县实施"无鼠害示范区"项目调查

刚察县在2001～2003年实施了“无鼠害示范区“项目,通过项目的实施天然草地的生态环境得到了明显改善,草原鼠害得到了有效控制,草地植被得到恢复,产草量明显增加,为刚察县畜牧业可持续发展打下了良好的基础.     

奶牛MTT比色法的最佳条件探讨

为建立奶牛淋巴细胞增殖反应MTT比色法,对试验条件进行了研究。应用L16(45)正交试验,对影响MTT比色法的四个主要因素,包括ConA浓度、细胞浓度、培养液小牛血清浓度及培养时间进行了比较和探索。试验表明几个因素对其增殖反应都有显著影响(P<0.05),且最佳反应条件为:15μg/mL的ConA、1×106/mL细胞浓度、10%小牛血清及60h的培养时间;影响增殖反应的先后顺序为细胞浓度、ConA浓度、培养时间及血清浓度。