Cloning, functional expression, and characterization of cystatin in sesame seed

A cDNA fragment encoding cystatin, a cysteine protease inhibitor, was obtained from maturing sesame seeds. The clone was constructed in a nonfusion or fusion vector and then overexpressed in Escherichia coli. The recombinant cystatins were found in the soluble fraction of cell extract and were demonstrated to be functionally active in a reverse zymographic assay. The corresponding endogenous 22 kDa cystatin of low abundance in mature seeds was purified to homogeneity via a papain-coupling affinity column and confirmed by western blotting with antibodies against the recombinant cystatin. Both endogenous and recombinant cystatin proteins showed effective inhibitory activities against papain with K(i) values of 7.89 x 10(-8) M and 2.77 x 10(-8) M, respectively. Immunodetection indicated that cystatin was specifically expressed in maturing seeds and rapidly degraded in germination. Accordingly, zymographic and inhibition analyses showed that sesame cystatin could not inhibit the de novo synthesized proteases in germinating seeds. It is suggested that sesame cystatin may play a role in the regulation of endogenous cysteine proteases during seed maturation and germination.     

土壤中POPs检测方法参数的优化

 研究了环境土壤中部分毒害性有机污染物的多残留监测确证技术,采用符合实际的采样方案,应用超声提取、固相萃取前处理及净化手段,充分发挥气相色谱（GC）双柱双检测器和气相色谱-质谱联用（GC-MS）选择离子监测（SIM）优势互补技术,建立了环境土壤中艾氏剂等10种持久性有机污染物多残留检测确证方法。充分挖掘GC和MS的互补优化技术,通过标准添加和对实际样品的监测,证明方法具有前处理简洁、速度快、定量检测和定性确证结合、适合批量等优点。     

闲置沼气池产生的原因及对策

近年来，随着国家对农户用沼气池建设的不断加强和建设投资的逐年增大，我国农村沼气事业取得了长足发展。特别是“三沼”综合利用技术在农业生产上的成功推广，提升了农村沼气利用的内涵，为农业和农村循环经济的发展拓宽了空间。但是，在沼气建池数不断增加的同时，亦产生了沼气池闲置的问题，这与快速发展的沼气项目建设不相适应。针对这一问题，毕节地区对2003年建成的1．26万口沼气池的使用情况进行了随机抽样调查，     

湿气输送天然气管道腐蚀检测与安全性分析

为预测分析20号碳钢湿气输送天然气管道未来的腐蚀速率,选取了具有代表性的采气管段进行了极端情况下金属的损伤积累速度的腐蚀检测.结果表明,管道输气量和水气比是激化腐蚀的主导因素,指出腐蚀速率会随着输气量和水气比的增大而提高,在输气量和水气比相近的情况下,腐蚀速率随H2S含量增加而升高;在靠近焊缝的母材中H2S容易诱发氢致裂纹和脆化,并且随着天然气中H2S含量增加,氢致裂纹的倾向会加大.此外,受冲刷腐蚀的影响,弯管处的腐蚀速率较高.     

Identification of methanol-soluble compounds in sesame and evaluation of antioxidant potential of its lignans

The methanol extract of sesame (Sesamum indicum) seeds was fractionated and purified with the assistance of conventional column chromatography to afford 29 compounds including seven furofuran lignans. Among these isolates, (+)-samin (1) was obtained from the natural source for the first time. In addition, (-)-asarinin (30) and sesamol (31) were generated by oxidative derivation from (+)-sesamolin (2) and (+)-sesamin (3), two abundant lignans found in sesame seeds. To evaluate their in vitro antioxidant potential, the seven isolated lignans (1-7) and the two derivatives (30 and 31) were examined for the scavenging activities on DPPH free radicals and superoxide anions. Moreover, the capability of chelating ferrous ions and reducing power of these sesame lignans were also measured. The results suggest that, besides the well-known sesamolin and sesamin, the minor sesame lignans (+)-(7S,8'R,8R)-acuminatolide (5), (-)-piperitol (6), and (+)-pinoresinol (7) are also adequate active ingredients and may be potential sources for nutritional and pharmacological utilization.     

Policosanol has no antioxidant activity in human low-density lipoprotein but increases excretion of bile acids in hamsters

Policosanol is a group of long chain primary alcohols and has been shown to reduce blood cholesterol levels and to inhibit the oxidation of low-density lipoprotein (LDL). The present study examined (i) the effect of policosanol supplementation in the diet on the fecal excretion of neutral and acidic sterols in hamsters and (ii) the antioxidant activity of policosanol in human LDL. Golden Syrian hamsters were divided into four groups (n = 12/each) fed one of the four diets containing 0 (control), 0.38, 0.75, and 1.50 g kg(-1) policosanol for 6 weeks. It was found that hamsters given 0.38-1.5 g kg(-1) diets had a serum total cholesterol level lowered by 15-25% and had a high-density lipoprotein cholesterol elevated by 7-16.8%. It was found that policosanol increased the excretion of acidic sterols by 25-73%. Contrary to that in previous reports, policosanol had no apparent anti-LDL oxidation activity when 1-tetracosanol, 1-hexacosanol, and 1-octacosanol were incubated in human LDL. Policosanol also possessed no scavenging activity on the free radical2,2-diphenyl-1-picrylhydrazyl. These data provide evidence that in addition to the effect of HMG-CoA reductase, the cholesterol-lowering activity of policosanol is partially mediated by its inhibition on the absorption of bile acids, but these data disprove the claim that policosanol is an antioxidant.     

生物代谢氧化还原化学检验新方法及其应用研究

生物代谢氧化还原的化学分析方法是一种速度快、操作简、效果好的比较研究光合作用强度及呼吸作用强度的新方法.笔者将其测定方法应用于生产实践,可比较出不同情况下作物光合或呼吸作用强度、阐明作物高低产实质及应用于作物生理病害诊断等.     

Identification and characterization of a late gene encoded by grouper iridovirus 2L (GIV‐2L)

Grouper iridovirus (GIV) belongs to the Ranavirus genus and is one of the most important viral pathogens in grouper, particularly at the fry and fingerling stages. In this study, we identified and characterized the GIV‐2L gene, which encodes a protein of unknown function. GIV‐2L is 1242 bp in length, with a predicted protein mass of 46.2 kDa. It displayed significant identity only with members of the Ranavirus and Iridovirus genera. We produced mouse monoclonal antibodies against the GIV‐2L protein by immunizing mice with GIV‐2L‐His‐tag recombinant protein. By inhibiting de novo protein and DNA synthesis in GIV‐infected cells, we showed that GIV‐2L was a late gene during the viral replication. Finally, immunofluorescence microscopy revealed that GIV‐2L protein accumulated in both the nucleus and cytoplasm of infected cells. These results offer important insights into the pathogenesis of GIV.     

Assessment of the tumorigenesis and drug susceptibility of three new canine mammary tumor cell lines

Three canine mammary tumor (CMT) cell lines, namely DE-E, DE-F and DE-SF, have been established from a surgically excised specimen of a malignant mammary tumor. These CMT cell lines have been cultured for over 200 passages. The cell doubling time was estimated to be approximately 30 h for all three cell lines. DE-E, DE-F and DE-SF were epithelial, fibroblast and spindle fibroblast in morphology, respectively. Under electron microscope, DE-F and DE-SF cells displayed a higher nucleus/cytoplasm ratio as compared with DE-E. Variation in chromosome number was also observed in the three cell lines. In addition to the morphological characteristics, these cell lines displayed differential patterns of several known mammary tumor cell markers. Following xenotransplantation of the CMT cells into nude mice, DE-F and DE-SF developed tumors within 2 weeks, whereas DE-E failed to develop any visible tumor up to 8 weeks after injection. Lastly, the CMT cell lines exhibited differential chemoresistance to several anti-tumor drugs, including melatonin, cyclosporine A, tamoxifen and indole, suggesting that these cell lines can be used as a comparative experimental model for the tumorigenesis of mammary carcinomas and a valuable tool for anti-cancer drug screening.     

杂交稻叶面专用新药“稻多收”的增产效果研究

三年多来,新药"稻多收"已经用于杂交稻生产.本文报道了它的施用方法、增产效果及原因.在一般情况下,只需施药一次,每亩200克,叶面喷施,亩增产稻谷在50公斤以上.