巴豆醛-DNA加合特性的研究

目的 探讨巴豆醛和DNA加合特性,寻找优势反应核苷酸,初步确定对DNA损伤机制.方法 采用体外测试系统,应用高效液相色谱法对巴豆醛与4种单脱氧核苷酸的加合反应、加合物键型、反应级数进行研究.结果 经高效液相色谱仪(HPLC)分离检测,巴豆醛与脱氧鸟苷酸反应,确定了巴豆醛与4种单脱氧核苷酸结合的优势反应核苷酸.结论 巴豆醛能够与DNA的脱氧鸟苷酸结合而体现遗传特性,鸟苷的N2位可能是共价加合的位点.     

HPLC法研究苯乙烯-DNA的加合特性

目的：研究苯乙烯的DNA加合特性。方法：采用高效液相色谱法研究苯乙烯-7，8-氧化物（S0）、苯乙烯、苯乙醇酸（MA）、苯乙醛酸（PGA）和DNA的加合反应。结果：苯乙烯、MA、PGA不与DNA发生加合反应；SO可与脱氧鸟苷酸及脱氧腺苷酸发生加合反应，生成以共价键结合的加合物。结论：苯乙烯进入机体后，通过其活性中间代谢物SO与DNA起加合作用，SO攻击DNA脱氧鸟苷酸及脱氧腺苷酸形成加合物，如果在细胞复制前所形成的DNA加合物没有被修复或者被错误修复的话，就有可能导致基因突变。苯乙烯的其他代谢物未见此效应。     

苯乙烯-DNA加合特性的研究

目的 研究苯乙烯的DNA加合特性。方法 采用紫外光谱移动法测定苯乙烯－7，8－氧化物（SO）、苯乙烯、苯乙醇酸（MA）、苯乙醛酸（PGA）、苯乙烯巯基尿酸（UMA）和DNA的加合反应；以^32P后标记法研究SO－DNA加合物；以气相色谱－质谱、核磁共振研究SO－DAN加合物的结构。结果 苯乙烯、MA、PGA和UMA不与DNA发生加合反应；SO分别在DNA脱氧鸟苷碱基上的O^6位、N^2位形成6种加合物。结论 苯乙烯进入机体后，通过其活性中间代谢物SO与DNA起加合作用，SO攻击DNA脱氧鸟苷碱基上的O^6位、N^2位形成加合物，如果在细胞复制前所形成的DNA加合物没有被修复或者被错误修复的话，就有可能导致基因突变，产生化学损伤。苯乙烯的其他代谢物未见此效应。     

BPDE—DNA加合物体外生成实验研究

目的：探讨体外合成苯并（a）芘与DNA形成加合物的条件.方法：以一定比例混合苯并（a）芘丙酮溶液、DNA溶液、S9混合液、于37℃孵育24 h后,紫外分光光度计扫描DNA图谱,得出DNA结构改变的信息;同时用HPLC检测反应体系中的苯并（a）芘含量、苯并（a）芘代谢物及DNA加合物酸水解后的产物.确定BPDE-DNA加合物生成,质谱验证生成物的结构.结果：反应后DNA紫外最大吸收峰红移;HPLC检测发现孵育后反应体系中苯并（a）芘含量降低,反应管有新的物质生成;质谱分析生成物的分子量同于目标产物.结论：一定条件下体外可合成苯并（a）芘-DNA加合物.     

人血中三硝基甲苯血红蛋白加合物的结构鉴定和定量分析

建立高效液相色谱定量测定三硝基甲苯（ＴＮＴ）血红蛋白（Ｈｂ）加合物的方法，并用于分析人的Ｈｂ加合物。结果表明，ＴＮＴ在体外可与人Ｈｂ反应形成加合物，并发现至少有两种类型：酸不稳定型和稳定型。前者占所有ＴＮＴ－Ｈｂ加合物的７１％。接触ＴＮＴ工人的Ｈｂ水解后，用液相色谱／质谱／质谱（ＬＣ／ＭＳ／ＭＳ）首次鉴定出了个４－氨基－２，６－二硝基甲苯（４Ａ），但未检测出在大鼠实验中所发现的２－氨基－４，６－二硝基甲苯（２Ａ）；接触组加合物浓度范围为０．０１４～０．７９２μｇ／ｇＨｂ。对照组未检出Ｈｂ加合物。     

体外甲基丙烯酸环氧丙酯-DNA加合物的研究

目的 探讨新诱变剂甲基丙烯酸环氧丙酯（ＧＭＡ）与ＤＮＡ形成加合物的类型和特性。方法 在体外条件下,dＡＭＰ、dＣＭＰ、dＧＭＰ、dＴＭＰ及小牛胸腺ＤＮＡ与ＧＭＡ发生反应,反应产物经紫外光谱、反相高效液相色谱（ＲＰ－ＨＰＬＣ）和质谱先进方法分析。结果 ＧＭＡ能与dＡＭＰ、dＣＭＰ、dＧＭＰ及小牛胸腺ＤＮＡ形成专一性共价结合。已 被证实１捉ＧＭＡ－ＤＮＡ加合物为Ｎ３－甲基丙烯酸－２羟丙－基－脱氧胞嘧啶核苷一磷     

不同膳食硒水平对甲基苄基亚硝胺（NMBzA）诱发大鼠食道上皮细胞DNA烷基化和

本文报道了硒对NMBzA诱发大鼠食道上皮细胞DNA加合物的形成，DNA加合物修复酶（甲基转移酶）的活性以及-cmyc的基因表达的影响，一次腹腔注射NMBzA 2.5mg/Kg体重，6小时后测定产食上皮细胞中O6－甲基脱氧鸟嘌呤核甙酸（O6－MedGua)和N7－甲基脱氧鸟嘌呤核甙酸（N7－MedGua)的含量，结果表明饲料中不同硒含量对DNA加合物无明显影响；对O6－MedGua DNA甲基转移酶活性也无明显作用，给大鼠每周一次灌胃NMBzA 3mg/kg体重，共8周诱发大鼠食道上皮细胞c-myc基因表达，结果膳食缺硒（＜0．02ppm)和补硒（2ppm)对 c-myc基因表达亦无影响.     

气相色谱-质谱法检测保健食品中角鲨烯

角鲨烯 (squalene)又名鲨烯 ,鲨萜 ,是一种高度不饱和烃类化合物 ,其系统命名为 2 ,6,10 ,15 ,19,2 3—六甲基— 2 ,6,10 ,14 ,18,2 2—二十四碳六烯 ,分子式为C3 0H5 0 ,相对分子量为 410 .7。角鲨烯在常温下为无色油状液体 ,通常以富含此组分的大鲨鱼肝为原料进行提取。角鲨烯具有类似红细胞的携氧功能 ,提高机体组织对氧的利用能力 ,促进新陈代谢 ,增强机体免疫力 ,加速消除因缺氧所致的各种疾病 ,是保健食品功效成分之一。角鲨烯的分析方法多为气相色谱法和液相色谱法 ,气相色谱—质谱法则未见报道。本文以气相色谱—质谱法检测保健食…     

反向高效液相色谱法测定依普黄酮

依普黄酮 (Ipriflavone)又名依普拉封 ,化学名为 7-异丙氧基异黄酮 ,分子式C1 8H1 6 O3,具有类似雌性激素的作用[1 ] ,现已被广泛地使用于牲畜、家禽及水产品养殖的混合饲料中。本文探索用反向高效液相色谱法测定混合饲料中依普黄酮含量的方法。材料与方法1　仪器　LC - 10AT高效液相色谱仪带SPD - 10A紫外检测器 (日本岛津 ) ;Shim packCLC ODS (15 0mm× 4 6mm× 5 μm) ;N2 0 0 0色谱工作站 (浙江大学智能信息工程研究所 )。2　试剂　甲醇 (一级色谱纯 ) ;盐酸 (AR) ;醋酸 (AR) ;醋酸胺 (AR) ;依普黄酮 (≥ 99 5 % ) ;二次蒸…     

反相高效液相色谱法检测食品中苏丹-1的含量

苏丹-1(Sudan-1)即1-(苯基偶氮)-2-萘酚,国内又称苏丹红一号、油溶黄;美国化学文摘号(CAS)为842-07-9;国际索引号:S.Y.14(12055).分子式C16H12N2O属偶氮类染料,主要用于塑料、油脂、肥皂、皮鞋油、地板蜡、蜡制品等的着色,但在一些国家也用于食品生产领域.有关研究表明,苏丹-1及其他一些偶氮类染料具有致癌性,我国和欧盟现都已禁止在生产过程中添加使用苏丹-1[1、2].本研究采用C18柱和紫外检测器,建立了测定食品中苏丹-1的高效液相色谱方法.     

氧化型染发剂DNA交联作用的研究

采用溴乙锭荧光法测定氧化型染发剂的主要成分对苯二胺（ＰＰＤ）、过氧化氢（Ｈ２Ｏ２）和ＰＰＤ－Ｈ２Ｏ２混合物对小牛胸腺ＤＮＡ的双链间交联形成作用。结果表明：用０～６％的对苯二胺及０～３％的Ｈ２Ｏ２对小牛胸腺ＤＮＡ直接染毒，３７℃３０ｍｉｎ时无双链间ＤＮＡ交链的形成；而ＰＰＤ和Ｈ２Ｏ２发生氧化反应后则具有双链ＤＮＡ交联形成作用并具有剂量反应关系（ｒ＝０．８２９，Ｐ＜０．０１），在受试剂量为０～０．８％（以对苯二胺含量计）时，氧化型对苯二胺的ＤＮＡ交联作用增加了４．２倍。研究结果提示，ＤＮＡ交联作用可能是氧化型染发剂遗传毒作用过程中ＤＮＡ损伤的一种方式。     

Synthesis, antibacterial, antifungal activity and interaction of CT-DNA with a new benzimidazole derived Cu(II) complex

The ligand [C(16)H(10)O(2)N(4)S(2)] L has been synthesized by the condensation reaction of 2-mercaptobenzimidazole and diethyloxalate. The ligand L was allowed to react with bis(ethylenediamine)Cu(II)/Ni(II) complexes to yield [C(20)H(22)N(8)S(2)Cu]Cl(2)1 and [C(20)H(22)N(8)S(2)Ni]Cl(2)2 complexes. The Ni(II) complex was synthesized only to elucidate the structure of the complex. The complexes 1 and 2 were characterized by elemental analyses, IR, NMR, EPR, UV-vis spectroscopy and molar conductance measurements. Both the complexes are ionic in nature and possess square-planar geometry. The binding of the complex 1 to calf thymus DNA was investigated spectrophotometrically. The absorption spectra of complex 1 exhibits a slight red shift with "hyperchromic effect" in presence of CTDNA. Electrochemical analysis and viscosity measurements were also carried out to ascertain the mode of binding. The complex 1 in the absence and in presence of CT DNA in aqueous solution exhibits one quasi-reversible redox wave corresponding to Cu(II)/Cu(I) redox couple at a scan rate of 0.2 V s(-1). The shift in DeltaE(p), E(1/2) and I(pa)/I(pc) values ascertain the interaction of calf thymus DNA with copper(II) complex. There is decrease in viscosity of CTDNA which indicates that the complex 1 binds to CTDNA through a partial intercalative mode. The antibacterial and antifungal studies of the [C(7)H(6)N(2)S], [C(4)H(16)N(4)Cu]Cl(2,) [C(16)H(10)N(4)S(2)O(2)] and [C(20)H(22)N(8)S(2)Cu]Cl(2) were carried out against S. aureus, E. coli and A. niger. All the results reveal that the complex 1 is highly active against the bacterial strains and also inhibits fungal growth.     

三种醛类化合物-DNA加合特性的研究

目的 探讨甲醛、乙醛和丙烯醛对DNA的损伤机制.方法 采用体外测试系统,应用高效液相色谱法(HPLC)对甲醛、乙醛、丙烯醛及其在人体内的代谢产物甲酸、乙酸、羟丙基巯基尿酸与4种单脱氧核苷酸的加合反应进行研究.结果 经HPLC分离检测,甲醛、醋醛与脱氧鸟苷酸发生加合反应,而丙烯醛、甲酸、醋酸和羟丙基巯基尿酸难以与脱氧鸟苷酸发生加合反应或加合物产量过低,初步确定了甲醛、乙醛与4种单脱氧核苷酸结合的优势反应核苷酸.结论 甲醛、乙醛能够与DNA的脱氧鸟苷酸结合而体现遗传特性.     

Synthesis and characterization of dinuclear macrocyclic cobalt(II), copper(II) and zinc(II) complexes derived from 2,2,2('),2(')-S,S[bis(bis-N,N-2-thiobenzimidazolyloxalato-1,2-ethane)]: DNA binding and cleavage studies

New homodinuclear macrocyclic complexes of cobalt(II), copper(II) and zinc(II) were isolated from the newly synthesized ligand 2,2,2',2'-S,S[bis(bis-N,N-2-thiobenzimidazolyloxalato-1,2-ethane)]. The structures of the complexes were elucidated by elemental analysis, molar conductance measurements, IR, 1H NMR, 13C NMR, electronic and ESI-MS spectroscopic techniques. In complex 1, Co(II) ions possess a tetrahedral coordination environment composed of O2S2 donor atoms while its Cu(II) and Zn(II) counterparts 2 and 3, respectively, reveal a six coordinate octahedral structure, defined by the O2S2 donors from the macrocyclic ring and two chloride ions. Molar conductance and spectroscopic data also support the proposed geometry of the complexes. DNA binding properties of complexes 1-3 were investigated using electronic absorption spectroscopy, fluorescence spectroscopy, viscosity measurements and cyclic voltammetry. The absorption spectra of complexes 2 and 3 with calf thymus DNA showed hypochromism, while complex 1 showed hyperchromism attributed to a partial intercalation and electrostatic binding modes, respectively. The intrinsic binding constant K(b) of complexes 1-3 were determined as 16.6 x 10(4) M(-1), 4.25 x 10(4) M(-1) and 3.0 x 10(4) M(-1), respectively. The decrease in the relative specific viscosity of calf thymus DNA with increasing concentration of the complexes authenticates the partial intercalation binding mode. Gel electrophoresis of complex 2 with plasmid DNA demonstrated that complex exhibits excellent "artificial" nuclease activity.     

饮茶抑制大鼠体内杂环胺-DNA加合物形成的机理

目的我们已报告饮茶可有效抑制２氨基１甲基６苯基咪唑并［４，５ｂ］吡啶（ＰｈＩＰ）在大鼠体内形成致癌物ＤＮＡ加合物，本研究旨在探讨这一作用机理。方法ＰｈＩＰ在体内经代谢活化形成终致癌物Ｎ乙酰氧基ＰｈＩＰ，后者与ＤＮＡ结合形成ＰｈＩＰＤＮＡ加合物。本研究模拟体内条件，观察茶水或茶多酚对化学合成的［３Ｈ］Ｎ乙酰氧基ＰｈＩＰ与ＤＮＡ反应的抑制作用，并以高效液相色谱分析反应产物。结果茶水和茶多酚均可显著抑制ＰｈＩＰ与ＤＮＡ结合，抑制效果与加入的茶水或茶多酚呈浓度效应关系。在所测试的茶水和茶多酚中，在同等浓度下，绿茶抑制效果优于红茶，绿茶多酚优于红茶多酚。高效液相色谱分析未发现［３Ｈ］Ｎ乙酰氧基ＰｈＩＰ与茶多酚的结合物，而反应体系中的主要产物是母体杂环胺ＰｈＩＰ。结论茶多酚抑制Ｎ乙酰氧基ＰｈＩＰ与ＤＮＡ结合的作用机理，是直接将Ｎ乙酰氧基ＰｈＩＰ还原成ＰｈＩＰ，使之失去亲电子的能力从而抑制ＰｈＩＰＤＮＡ加合物形成。鉴于茶多酚和Ｎ乙酰氧基ＰｈＩＰ均可在血循环和组织中存在，两者之间的直接反应可能是饮茶抑制体内ＰｈＩＰＤＮＡ加合物形成的机理     

Biological evaluation of a novel water soluble sulphur bridged binuclear copper(II) thiosemicarbazone complex

The reaction of 2-oxo-1,2-dihydroquinoline-3-carbaldehyde 4(N,N)-dimethylthiosemicarbazone (HL) with copper(II) nitrate in methanol yielded water soluble [{Cu(L)(CH(3)OH)}(2)](NO(3))(2) · H(2)O. Structural analysis revealed that the complex consists of centrosymmetric binuclear entities containing square-pyramidal copper(II) ions bridged through the sulfur atoms. The spectroscopic experimental evidences strongly suggested that the ligand and complex could interact with calf thymus DNA (CT-DNA) through intercalation. A gel electrophoresis assay demonstrated the ability of the complex to cleave the pBR322 plasmid DNA. The complex also exhibited a strong binding to bovine serum albumin (BSA) over the ligand. Investigations of antioxidative properties showed that the complex has strong radical scavenging properties. Further, the cytotoxic effect of the complex was examined on HeLa, Hep G2, and HEp-2, which showed that the complex exhibited substantial cytotoxic specificity on HeLa over the other two.     

Effects of dietary conjugated linoleic acid on DNA adduct formation of PhIP and IQ after bolus administration to female F344 rats

Meats cooked at high temperatures contain mutagenic heterocyclic amines such as 2‐amino‐l‐methyl‐6‐phenylimidazo[4,5‐b]pyridine (PhIP) and 2‐amino‐3‐methylimidazo[4,5‐f]quinoline (IQ). In female Fischer 344 rats, IQ is a multiorgan carcinogen, whereas PhIP induces mammary adenocarcinomas. For IQ and PhIP, N‐hydroxylation, catalyzed by microsomal cytochrome P‐450 1A1 and/or 1A2, and then esterification, especially O‐acetylation, are the principal steps leading to DNA adduct formation. Conjugated linoleic acid (CLA) is a mixture of conjugated linoleic acid isomers found in various meat and dairy products. We have examined the effect of dietary CLA on DNA adduct formation by PhIP and IQ in female Fischer 344 rats. Four‐week‐old animals were maintained on AIN‐76A diet without or with CLA (4% wt/wt) and treated with IQ or PhIP (50 mg/kg by gavage) after two weeks. Animals were killed (4/group) one, four, and eight days later. DNA isolated from mammary epithelial cells, liver, colon, and white blood cells was analyzed for carcinogen‐DNA adducts by ³²P‐postla‐beling assays. On Day 1, dietary CLA significantly inhibited adduct formation (82.0%) in mammary epithelial cells in IQ‐but not in PhIP‐treated rats. In the colon, dietary CLA significantly inhibited PhIP‐DNA adduct formation (18.7%) on Day 8 but increased IQ‐DNA adduct formation (30.5%) on Day 8. Dietary CLA had no effect on adduct levels in liver or white blood cells. Calf thymus DNA was incubated with N‐hydroxy‐PhIP or ‐IQ in the presence of acetyl‐CoA. Enzymatic activation was catalyzed by liver or mammary cytosol. A two‐week pretreatment with 2% (wt/wt) dietary CLA had no effect on O‐acetyltransferase‐catalyzed IQ‐ or PhIP‐DNA adduct formation. It is concluded, under certain conditions, that dietary CLA can lower IQ‐ and PhlP‐DNA adduct formation. Overall, however, the major mode of action of CLA is probably by a mechanism other than the inhibition of the N‐hydroxylation and subsequent O‐acetylation of PhIP or IQ.