(Ni-Sn-M_xO_y)/Pb改性复合电极电解合成L-半胱氨酸的反应

在（Ｎｉ－Ｓｎ）／Ｐｂ合金修饰电极中添加某些金属氧化物进行改性,用于电解合成Ｌ－半胱氨酸反应。结果证明,添加ＷＯ３后电极反应活性大大加强,反应同期转化率有较大提高,选择性也有所提高,添加稀土金属氧化物能有效降低反应阴极过电位,使反应选择性有所提高,但是电极稳定性还有待改善。     

Simultaneous analysis of artemisinin and flavonoids of several extracts of Artemisia annua L. obtained from a commercial sample and a selected cultivar

Artemisia annua L. (Qinghao) is a promising and potent antimalarial herbal drug. This activity has been ascribed to its component artemisinin, a sesquiterpene lactone that is very effective against drug-resistant Plasmodium species with a low toxicity. Our studies indicate that several flavonoids of A. annua can promote and enhance the reaction of artemisinin with hemin. These data are in good agreement with previous investigations on the in vitro potentiation of antimalarial activity of artemisinin by such flavonoids. As a consequence, in view of a possible use of the phytocomplex rather than pure artemisinin, an HPLC/DAD/MS method is proposed for the simultaneous detection and quantification of both flavonoids and artemisinin. Different extracts, obtained from two different herbal drugs, a commercial sample and a selected cultivar, were analyzed in order to determine which solvents provide the best yields of both artemisinin and flavonoids. Qualitative and quantitative results obtained using an HPLC method are described, which will be useful for developing highly effective herbal drug preparations.     

5-氟尿嘧啶增强HeLa细胞对自然杀伤细胞敏感性研究

目的用5-氟尿嘧啶（5-fluorouracil,5-FU）处理HeLa细胞,检测其NKG2D配体MICA的表达及其对NK92细胞杀伤敏感性的变化。方法不同浓度的5-Fu处理HeLa细胞,在不同时间点用半定量PCR及流式细胞术检测HeLa细胞表面的NKG2D配体MICA在RNA及蛋白水平的表达变化情况,用MTT法检测NKG2D抗体封闭NK92细胞的NKG2D受体前后,NK92细胞对HeLa细胞的杀伤作用。结果不同浓度的5．Fu作用于HeLa细胞后,半定量RT—PCR结果显示MICA表达随5-Fu作用浓度增加逐渐增高。而且40μg／ml5．Fu作用于HeLa细胞后随着作用时间的延长（0、8、16、24h）MICA表达增加,流式细胞术检测结果表明,MICA表达的增加主要依赖于未凋亡细胞的MICA表达。在40μg／ml5-FU作用24h,效靶比为2．5：1,5：1,10：1,20：1时都检测到NK92细胞对HeLa细胞的杀伤增强,杀伤作用可部分被NKG2D抗体抑制。结论5-FU能够上调HeLa细胞表面NKG2D配体MICA的表达,增强HeLa细胞对NK92细胞的敏感性,提示化疗联合NK细胞免疫治疗宫颈癌可产生协同作用,提高治疗效果。     

产黄酮银杏内共生真菌的分离及其发酵条件的优化

本文从不同年龄、不同地域的银杏叶、茎、根部组织中分离得到20株银杏内共生真菌,经过发酵复筛有5株的产黄酮能力超过5μg/m L。实验对菌株的最佳发酵产黄酮条件进行了优化,优化条件为:3%葡萄糖、0.5%蛋白胨、0.4%酵母膏、0.3%KH2PO4、0.01%Mg SO4·7H2O;起始p H值7.0、最适发酵温度28℃、摇床转速为140 r/min、装液量125 m L/250 m L。在此条件下,该系列菌株在发酵7 d左右产黄酮量可达6.4μg/m L。     

特早熟甘蓝型油菜异交率的测定

利用SSR分子标记技术构建3个特早熟甘蓝型油菜恢复系的指纹图谱,筛选出这3个恢复系的共显性SSR标记,测定了这3个恢复系的异交率。结果表明,恢复系材料4395、3509、4152的异交率分别为46.02%、33.32%、18.12%,在P<0.01时呈极显著差异,说明这3个恢复系的异交差异明显,为确定这3个恢复系在综合杂交种中的比例提供依据。     

Reduction of superoxide production by mitochondria oxidizing NADH in the presence of organic acids

Effects of multiple substrates on oxygen uptake and superoxide production by mitochondria isolated from the pericarp tissue of green bell pepper (Capsicum annuum L.) were studied. Mitochondria isolated from peppers stored at 4 °C for 5 and 6 days had higher rates of oxygen uptake and were less sensitive to cyanide than mitochondria isolated from freshly harvested peppers. Succinate enhanced state 2 and state 4 rates of oxygen uptake with exogenous NADH in the absence of cytochrome path inhibitors, but not state 3 rates by mitochondria isolated from either freshly harvested or cold-stored bell peppers. The sensitivity of NADH oxidation to cyanide was reduced by both malate and succinate in mitochondria from cold-stored bell peppers, whereas only succinate was effective in mitochondria from freshly harvested peppers.Mitochondria isolated from both freshly harvested peppers and those stored at 4 °C for 5 and 6 days produced superoxide in the absence of exogenous substrates. Superoxide production by mitochondria from freshly harvested bell peppers increased when the mitochondria were supplied with malate, succinate or NADH, but only NADH enhanced superoxide production by mitochondria from cold-stored peppers. Both succinate and malate reduced the production of superoxide by mitochondria isolated from cold-stored bell peppers. Succinate and malate as second substrates also reduced the production of superoxide with NADH by mitochondria from both freshly harvested and cold-stored bell peppers. Malonate, a competitive inhibitor of succinate dehydrogenase, was inhibitory to oxygen uptake and to superoxide production.Mitochondria isolated from cold-stored bell peppers converted succinate to pyruvate at 25 °C at considerably higher rates than those of mitochondria from freshly harvested bell peppers. Since pyruvate has been shown to activate the alternative oxidase and the presence of pyruvate is essential for continued alternative oxidase activity, we suggest that pyruvate limits superoxide production by enhancing the flow of electrons through the alternative path. A direct scavenging of superoxide by succinate, malate and pyruvate, however, cannot be ruled out.     

向日葵染色体Giemsa C-带带型分析

采用HKG(HCl-KOH-Giemsa)法对内葵杂3号三交种染色体进行了C-分带研究和分析。结果表明:每条染色体至少都有一条C-分带,染色体组共有62条C-分带,以中间带和着丝点带为主,中间带主要分布在染色体短臂上;C-分带强弱差异明显,其中46条强带,16条弱带。Giemsa C-分带带型公式为:2n=2x=34=8I++3T++5I+I+T++4C+2CI+4CI++3CI++I+T++CT++2CT+。每条染色体都显示出显著的带纹特征,因此,利用Giemsa C-分带方法可以将向日葵的每条染色体区分开。     

Isolation and characterization of the Δ12-fatty acid desaturase in peanut (Arachis hypogaea L.) and search for polymorphisms for the high oleate trait in Spanish market-type lines

An understanding of the molecular mechanisms that are responsible for increased oleic acid accumulation would open avenues to alter peanut fatty acid composition and allow detection of polymorphic regions which can be used for marker assisted selection (MAS). Δ¹²-Fatty acid desaturase (FAD) was isolated and characterized from genotypes having a low or high oleic to linoleic acid O/L ratio – genotypes, Tamspan 90 (T-90) and F435–2-2 (F435), respectively. Southern blots showed three to four copies per haploid genome, and no major differences in organization between the two parental lines. Approximately 3525 bp was isolated from both genotypes, including a genomic walk toward the promoter region. The Δ¹²-Fad contains a putative intron, the coding region at the 3′ end, and an open reading frame (ORF) of 1140 bp encoding 379 amino acids. Comparisons of the coding sequences from the high and low oleic acid genotypes revealed several single nucleotide polymorphisms (SNPs). Two polymorphisms appear to be associated with the high O/L trait. The first is an ”A” insertion 442 bp after the start codon. The ”A” insertion shifts the amino acid reading frame, probably resulting in a truncated, inactive protein and the loss of one of three histidine boxes believed to be involved in metal ion complexation required for the reduction of oxygen. Another polymorphism at 448 bp from the start codon results in an amino acid change. The region containing the polymorphisms was amplified from leaf tissue of several independently derived backcross lines (IDBLs). Most high O/L lines had either the ”A” insertion or the amino acid substitution. Received: 1 February 2000 / Accepted: 20 March 2000     

长效肥料ENTEC对野生刺苋驯化栽培的影响

探讨了含有硝化抑制剂DMPP(3,4-二甲基吡唑磷酸盐)的长效肥料ENTEC对剌苋(Amaranthus spinosus L.)干物质积累及其氮素利用的影响. 结果表明: 与尿素处理相比,ENTEC对提高剌苋干物质积累作用不明显,其最大生长速率出现时间较晚; 施用ENTEC,土壤含氮量较高,且下降速度较慢,说明其具有较强的防止氮素流失的作用.同时,ENTEC有利于提高氮素的利用率,ENTEC处理的植株氮素利用率比尿素处理提高了41.56%.另外,ENTEC能促进剌苋对磷、钾素的吸收.     

Bile acid receptors as targets for the treatment of dyslipidemia and cardiovascular disease

Dyslipidemia is an important risk factor for cardiovascular disease (CVD) and atherosclerosis. When dyslipidemia coincides with other metabolic disorders such as obesity, hypertension, and glucose intolerance, defined as the metabolic syndrome (MS), individuals present an elevated risk to develop type 2 diabetes (T2D) as well as CVD. Because the MS epidemic represents a growing public health problem worldwide, the development of therapies remains a major challenge. Alterations of bile acid pool regulation in T2D have revealed a link between bile acid and metabolic homeostasis. The bile acid receptors farnesoid X receptor (FXR) and TGR5 both regulate lipid, glucose, and energy metabolism, rendering them potential pharmacological targets for MS therapy. This review discusses the mechanisms of metabolic regulation by FXR and TGR5 and the utility relevance of natural and synthetic modulators of FXR and TGR5 activity, including bile acid sequestrants, in the treatment of the MS.