Antimicrobial efficiency of some N,N′-bis(alkymethyl)-1,2-ethanediamine dioxides and N,N′-bis(alkylmethyl)-1,2-propanediamine dioxides

Ten dioxide species derived from N,N′-bis(alkylmethyl)-1,2-ethanediamine and N,N′-bis(alkylmethyl)-1,2-propanediamine were tested for their activity withStaphylococcus aureus, Escherichia coli andCandida albicans. A relation between the length of the alkylchain, and/or the molecule asymmetry, and the antimicrobial activity was found. Part V of the series Amine Oxides; part IV: Mlynarciket al.: Folia Microbiol. 24, 188 (1979).     

BRIEF INTRODUCTI0N TO ISSN 0253-2700

Key title=YUNNAN ZHIWU YANJIU Latin name=Acta Botanica Yunnanica (Quartely.Started in 1979.Date of issue:the 5th of February,May,August and November.Number of pages:ca.120).     

过硫酸铵-N,N,N′,N′-四甲基乙二胺体系产生的氧自由基及其清除的研究

应用ESR和自旋捕集相结合的技术直接测定了过硫酸铵—N,N,N′,N′-四甲基乙二胺(AP-TEMED)体系产生的氧自由基,经计算机波谱模拟和计算波谱参数证实该体系产生的氧自由基是O_2~-和·OH。并用维生素C、茶多酚、超氧化物歧化酶等氧自由基清除剂,从聚丙烯酰胺凝胶法、化学发光法和脂质过氧化法不同角度研究了AP-TEMED体系在自由基研究方面的应用意义。     

N6-甲基腺嘌呤修饰与环状RNA

N6-甲基腺嘌呤(N6-methyladenosine,m6A)是发生在腺嘌呤第6位氮原子上的甲基化修饰,广泛存在于多种真核生物的RNA中。环状RNA(circular RNA,circRNA)是一类表达稳定的非编码RNA。该文分别从m6A影响circRNA的形成和翻译、降解、出核、先天免疫,通过下游分子影响circRNA的方面,以及circRNA竞争性结合三种m6A相关酶影响其他RNA的m6A修饰,海绵吸附微小RNA(microRNA,miRNA)靶向m6A相关酶,调控甲基转移酶的表达,结合去甲基化酶的mRNA促进其表达,增强去甲基化酶与mRNA的相互作用,结合并参与泛素化降解m6A结合蛋白的方面,及其他间接联系方面总结归纳了二者之间的作用机制,以期为研究m6A与circRNA相互影响的机制提供参考。     

过硫酸铵-N,N,N′,N′-四甲基乙二胺体系产生的氧自由基及其清除的研究

应用ESR和自旋捕集相结合的技术直接测定了过硫酸铵—N,N,N′,N′-四甲基乙二胺(AP-TEMED)体系产生的氧自由基,经计算机波谱模拟和计算波谱参数证实该体系产生的氧自由基是O_2~-和·OH。并用维生素C、茶多酚、超氧化物歧化酶等氧自由基清除剂,从聚丙烯酰胺凝胶法、化学发光法和脂质过氧化法不同角度研究了AP-TEMED体系在自由基研究方面的应用意义。     

NMR Studies of N 1- and N 3-(D-2′-Deoxyribofuranosyl) Nucleosides from Ethyl 5-Aminoimidazole-4-Carboxylate

Abstract

The conformation of deoxyribosides derived from N¹ and N³ substitution of the aglycone ethyl 5-aminoimidazole-4-carboxylate (AICE) has been determined by ¹H and ¹³C NMR spectroscopy. The deoxyribose ring shows considerable variation in the form and population of the contributing N and S conformers but the syn/anti ratio is similar to that in the purine analogues.     

EFFICIENT METHODS FOR THE SYNTHESIS OF [2-15N]GUANOSINE AND 2′-DEOXY[2-15N]GUANOSINE DERIVATIVES

The nucleophilic addition–elimination reaction of 2′,3′,5′-tri-O-acetyl-2-fluoro-O ⁶-[2-(4-nitrophenyl)ethyl]inosine (8) with [¹⁵N]benzylamine in the presence of triethylamine afforded the N ²-benzyl[2-¹⁵N]guanosine derivative (13) in a high yield, which was further converted into the N ²-benzoyl[2-¹⁵N] guanosine derivative by treatment with ruthenium trichloride and tetrabutyl-ammonium periodate. A similar sequence of reactions of 2′,3′,5′-tri-O-acetyl-2-fluoro-O ⁶-[2-(methylthio)ethyl]inosine (9) and the 6-chloro-2-fluoro-9-(β-D-ribofuranosyl)-9H-purine derivative (11), which were respectively prepared from guanosine, with potassium [¹⁵N]phthalimide afforded the N ²-phthaloyl [2-¹⁵N]guanosine derivative (15; 62%) and 9-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-6-chloro-2-[¹⁵N]phthalimido-9H-purine (17; 64%), respectively. Compounds 15 and 17 were then efficiently converted into 2′,3′,5′-tri-O-acetyl[2-¹⁵N]guanosine. The corresponding 2′-deoxy derivatives (16 and 18) were also synthesized through similar procedures.     

高产β-葡萄糖苷酶N1菌株的分类鉴定

从纳豆中分离纯化得到1株β-葡萄糖苷酶高产菌株,命名为N1菌,利用16S rDNA分析对该菌作了系统进化鉴定.首先提取N1菌基因组DNA,根据不同种属细菌的16S rDNA序列两端的保守性设计通用引物,对N1菌16S rDNA片断进行PCR扩增,对扩增得到的目标片段测序,利用BLAST对测序结果进行比对,构建系统进化树进行分析,初步确定该菌属于枯草芽孢杆菌.研究表明以16S rDNA分析对该菌鉴定完全可行.     

模拟N沉降下不同林龄马尾松林凋落叶分解-土壤C、N化学计量特征

模拟N沉降对森林生态系统的影响是当今全球变化生态学研究的一个热点问题,土壤碳库对N沉降比较敏感,N沉降增加了凋落叶分解过程中外源N含量,间接影响凋落叶分解的化学过程并改变凋落叶分解速率,因此,研究模拟N沉降下凋落叶分解-土壤C-N关系对预测森林C吸存有重要意义。利用原位分解袋法研究了模拟N沉降下三峡库区不同林龄马尾松林(Pinus massoniana)凋落叶分解过程中凋落叶-土壤C、N化学计量响应及其关系;N沉降水平分对照(CK,0 g m~(-2)a~(-1))、低氮(LN,5 g m~(-2)a~(-1))、中氮(MN,10 g m~(-2)a~(-1))和高氮(HN,15 g m~(-2)a~(-1))。结果表明:分解540 d后,N沉降促进20年生和30年生马尾松林凋落叶分解,46年生马尾松林中仅低氮处理促进凋落叶分解,4种处理均是30年生分解最快,说明同一树种起始N含量低的凋落叶对N沉降呈正响应,N沉降处理促进起始N含量低的凋落叶分解,起始N含量高的凋落叶分解过程中易达到"N饱和"。N沉降抑制20年生和46年生凋落叶C释放(低于对照0.62%—6.69%),促进30年生C释放(高于对照0.28%—5.55%);30年生和46年生林分N固持量均高于对照(高于对照0.15%—21.34%),20年生则低于对照(5.70%—13.87%),说明模拟N沉降处理促进起始C含量低的凋落叶C释放和起始N含量低的凋落叶N固持。N沉降处理下仅30年生马尾松林土壤有机碳较对照增加,且土壤有机质与凋落叶C、N和分解速率呈正相关,与凋落叶C/N比呈显著负相关;土壤总氮与凋落叶分解速率、凋落叶N含量呈正相关,土壤有机碳/总氮比与凋落叶C、N含量呈正相关;对照处理中凋落叶分解指标对土壤养分影响顺序是分解速率凋落物C含量凋落物C/N比凋落物N含量,低、中、高氮处理中则是凋落物C含量分解速率凋落物N含量凋落物C/N比。研究表明低土壤养分含量马尾松林对N沉降呈正响应,N沉降促进低土壤养分马尾松林凋落叶分解并提高土壤肥力;凋落叶质量和土壤养分含量低的生态系统土壤C对N沉降响应更显著。     

三种四膜虫全基因组N6-甲基腺嘌呤比较研究

为了揭示N6-甲基腺嘌呤(6mA)在近缘物种间的分布规律和物种进化过程中的变化, 研究在分离2种四膜虫(Tetrahymena malaccensis和Tetrahymena pyriformi)大核的基础上, 利用三代测序技术绘制了其全基因组单碱基分辨率6mA图谱, 结合公共数据库中已有的模式种Tetrahymena thermophila数据, 开展了3种四膜虫比较6mA甲基化组分析, 发现: (1)3种四膜虫6mA甲基化位点分布特征类似, 包括呈约200 bp周期性分布和具有保守AT基序; (2)6mA主要分布于基因的5′端, 在种间直系同源基因上的分布模式具有区域近似性, 但在单碱基水平不完全保守; (3)在种内近期复制的并系同源基因中, 6mA分布在单碱基水平具有较高的保守性; (4)结合3种四膜虫的分化时间, 估算出了四膜虫中6mA动态变化过程, 6mA位点建立的速度大约为每Mb每百万年69.9—226个位点。     

白细胞介素-2和狂犬病毒N蛋白基因重组与表达

研究白细胞介素－２ 与狂犬病毒Ｎ蛋白基因工程产物的免疫活性。采用生物工程技术,结果显示经基因扩增分别获得４００ｂｐ 和１４００ｂｐ 的ＩＬ－２ 和狂犬病毒Ｎ蛋白基因片段,构建了表达载体ＰＬＹ－４ＩＮ,于工程菌中转化后。得到５６ＫＤ重组蛋白产物,该产物具有ＩＬ－２活性,可诱导小鼠抵抗狂犬病毒攻击。     

不同取代度N,0-羧甲基壳聚糖的抗氧化性能

低聚壳聚糖经醚化得到三种取代度不同的 N,O-羧甲基壳聚糖(NOA、NOB和NOC),本文对其结构进行表征,考察了其对超氧阴离子自由基O2、DPPH 自由基和过氧化氢(H2O2)的清除活性和还原能力.结果表明NOA、NOB 和 NOC 对O2和 DPPH 的清除活性随-OH 位置取代度的降低而升高;对H2O2的清除率随一NH2位置取代度的降低而升高;还原能力大小随其总取代度的升高而增强.     

水痘-带状疱疹病毒糖蛋白N的单克隆抗体制备及初步研究

水痘-带状疱疹病毒(VZV)是水痘和带状疱疹的共同致病原,其糖蛋白N(gN)在子代病毒的组装、成熟和出胞过程中发挥重要作用。但是目前关于VZV gN的研究还很少,其蛋白性质和具体分子功能仍不清楚。本研究目的是制备抗VZV gN的单克隆抗体,对该蛋白在VZV感染细胞和人皮肤组织内的表达和分布情况进行初步探究。本研究选择抗原性和亲水性较强的gN区段基因,构建rGST-gN融合蛋白的原核表达质粒,将鉴定正确的重组质粒转化大肠杆菌后用IPTG诱导融合蛋白表达,经亲和层析柱纯化rGST-gN融合蛋白后使用PSP酶切除GST标签,将获得的重组蛋白rgN免疫BALB/c小鼠,使用杂交瘤技术制备其单克隆抗体;共获得24株稳定分泌抗VZV gN单克隆抗体的杂交瘤细胞株,选取其中一株性能最优的12E10进行单克隆抗体生产纯化和抗体鉴定;单克隆抗体12E10为IgG2a亚型,其ELISA效价达到1∶10 000;通过Western blot、免疫荧光及免疫组织化学染色方法鉴定,该抗体能够特异性识别细胞和组织中表达的VZV gN;本研究应用该抗体首次确定了gN在VZV感染细胞中的反式高尔基体定位,并且确定了gN在VZV感染人皮肤组织中的表达。以上工作为今后深入研究VZV gN功能奠定了基础。     

Human Naa50p (Nat5/San) Displays Both Protein Nα- and N?-Acetyltransferase Activity

Protein acetylation is a widespread modification that is mediated by site-selective acetyltransferases. KATs (lysine N^ϵ-acetyltransferases), modify the side chain of specific lysines on histones and other proteins, a central process in regulating gene expression. N^α-terminal acetylation occurs on the ribosome where the α amino group of nascent polypeptides is acetylated by NATs (N-terminal acetyltransferase). In yeast, three different NAT complexes were identified NatA, NatB, and NatC. NatA is composed of two main subunits, the catalytic subunit Naa10p (Ard1p) and Naa15p (Nat1p). Naa50p (Nat5) is physically associated with NatA. In man, hNaa50p was shown to have acetyltransferase activity and to be important for chromosome segregation. In this study, we used purified recombinant hNaa50p and multiple oligopeptide substrates to identify and characterize an N^α-acetyltransferase activity of hNaa50p. As the preferred substrate this activity acetylates oligopeptides with N termini Met-Leu-Xxx-Pro. Furthermore, hNaa50p autoacetylates lysines 34, 37, and 140 in vitro, modulating hNaa50p substrate specificity. In addition, histone 4 was detected as a hNaa50p KAT substrate in vitro. Our findings thus provide the first experimental evidence of an enzyme having both KAT and NAT activities.     

肝硬化患者内毒素、T N F -α和N O 水平与 高动力循环状态的相关性研究

目的：观察肝硬化患者血流动力学变化情况及血浆内毒素（LPS）、肿瘤坏死因子-α（TNF-α）和NO的水平并探讨之间相关关系。方法：试验检测血浆内毒素,双抗体夹心ELISA检测TNF-α,NO2^-／NO3^-测定采用硝酸还原法。并对CO、MAP、SVRI行同步观察。结果：健康组与肝硬化患者比较。失代偿组高动力循环状态特征明显。失代偿组、代偿组、健康组LPS、TNF-α、NO依次明显升高（P〈0．01）。血浆LPS与TNF-α和N0之间呈直线正相关。血浆NO水平与CO呈显著性正相关;与MAP、SVRI呈显著性负相关。结论：肝硬化患者血浆LPS、TNF-α、NO生成增多,NO在肝硬化血液动力学紊乱中起重要作用。     

Efficient Synthesis of [2-15N]Guanosine and 2′-Deoxy[2′-15N]Guanosine Derivatives Using N-(tert-Butyldimethylsilyl)[15N]Phthalimide as a 15N-Labeling Reagent

Nucleophilic aromatic substitution of 9-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-6-chloro-2-fluoro-9 H-purine with N-(tert-butyldimethylsilyl)[ ¹⁵ N]phthalimide in the presence of a catalytic amount of CsF at room temperature in DMF efficiently afforded the 6-chloro-2-[ ¹⁵ N]phthalimidopurine derivative, which was subsequently converted to the [2-¹⁵N]guanosine derivative was also efficiently synthesized through a similar procedure.     

Phospholipid bilayers as biological membrane models: The effect of N,N′-bis(dichloroacetyl)-1,12-diaminododecane

Summary N,N-bis(dichloroacetyl)-1,12-diaminododecane is a potent inhibitor of microsomal drug metabolism and also uncouples succinate-linked mitochondrial oxidative phosphorylation, apparently by promoting a transient permeability to anions. When added in very small concentrations to synthetic phospholipid bilayers made from a 144 mixture of purified cardiolipin, phosphatidylcholine, and phosphatidylethanolamine, the drug causes a rapid, transient decrease in electrical resistance with a return to an end-resistance somewhat lower than the initial one. The magnitude of the decrease was related to drug concentration. However, the drug produced a nontransitory, i.e. permanent decrease in resistance of bilayers made from pure phosphatidylcholine or cardiolipin. The 144 mixture of lipids, which closely resembles the lipid composition of the inner mitochondrial membrane yielded drug effects most closely resembling those observed in intact mitochondria. Transference number measurements on the 144 bilayer with an impressed KCl gradient revealed that the drug-induced decrease in electrical resistance was caused by an increase in the fraction of current carried by the anions in the system. The 144 phospholipid bilayer thus mimics the mitochondrial inner membrane in its response to this drug and indicates that the lipid composition of the lipid bilayer is a major determinant of at least some of its physical characteristics. The effect of varying the structure of the drug was also examined.     

Distribution of a Betaine Lipid O-(1,2-Diacylglycero)-4′-(N,N,N-Trimethyl)homoserine in Tissues of Some Lycopodiophyta Species

The distribution of O-(1,2-diacylglycero)-4-(N,N,N-trimethyl)homoserine (DGTS), a betaine lipid, in ten samples of plants belonging to the division Lycopodiophyta collected in various habitats was studied. Homogeneous plant tissues (vegetative shoots and spikelets) and mixed tissues (shoots with spikelets) were analyzed. A particular attention was paid to the DGTS-synthesizing ability of various club mosses, various tissue types forming an organ in a single plant species, as well as the ratio between DGTS and other glycerolipid classes.     

Effect of N,N′-bis (alkyldimethyl)-α,ω-alkanediammonium dibromides on bacteria of the genusclostridium

Antibacterial effect of 17 ammonium compounds of the type of N,N′-bis(alkyldimethyl)-α,ω-alkanediammonium dibromides was tested on anaerobically sporulating bacteria of the genusClostridium. A sizable antibacterial activity was displayed by five N,N′-bis(alkyldimethyl)-1,6-hexanediammonium dibromides and by four N,N′-bis(decyldimethyl)-α,ω-alkanediammonium dibromides. These compounds exhibited activity higher than, or comparable with, that of the reference standards Ajatin and Septonex. The maximum antibacterial activity was found in compounds whose alkyl chain contained 9–12 carbon atoms. Compounds with a lower number of carbon atoms in the chain (less than 8) exhibited a low activity.