不同烷基醛类对脱细胞-核DNA影响的研究

研究甲醛、乙醛、丙醛、丁醛、己醛、戊醛对脱细胞-核DNA的影响。方法 将甲醛、乙醛、丙醛、丁醛、己醛、戊醛用缓冲液分别配制浓度为10 mmol/L的溶液作为受试物;用羟自由基损伤的脱细胞-核DNA断片模型检测受试物与DNA交互作用的能力;用未经羟自由基处理的脱细胞-核DNA模型检测受试物导致DNA断裂的程度。两种模型均为每组6个平行板,处理时间均为60 min,用彗星实验检测DNA拖尾情况,每张板用彗星分析软件(Comet A1.0)分析50个脱细胞-核DNA,组间差异用SPSS 18.0软件进行统计学分析。结果 经甲醛处理的脱细胞-核DNA断片模型无DNA片段泳出;经乙醛处理的脱细胞-核DNA断片模型中DNA片段泳出量明显低于对照组;其他醛类对脱细胞-核DNA断片模型的DNA断片泳出量与对照组比较差异无统计学意义;所有醛类均未导致未经羟自由基处理的脱细胞-核DNA模型的DNA断裂。结论 甲醛和乙醛均可直接与脱细胞-核DNA断片形成加合物和/或产生DNA-DNA交联,且形成加合物和/或DNA-DNA交联的能力随醛类烷基数量的增加而减弱。     

DNA烷基化损伤研究进展

DNA的烷基化损伤可导致复制过程中的错配,被认为是引起基因突变及相关疾病的原因。烷基化DNA加合物是重要的DNA烷基化损伤产物。本文介绍了DNA烷基化损伤的修复机制,以及产物。综述了烷化类损伤试剂,及其作用于细胞产生烷基化加合物的机理。讨论了烷化类DNA加合物与吸烟之间的关系。综述了烷化类DNA加合物的检测方法,展望了烷基化DNA加合物的研究方向及作为烷基化损伤标志物的研究前景。      

醛类-DNA 加合物检测技术研究进展

甲醛、乙醛、丙烯醛和巴豆醛广泛存在于环境污染物中,卷烟烟气中也有微量存在,它们不需要经过机体代谢就能够直接进攻亲核基团,可与 DNA分子发生共价结合形成 DNA加合物。DNA加合物是 DNA损伤的一种形式,在 DNA复制过程中可使所携带的遗传信息发生改变,从而有可能造成机体的损伤。本文综述了生物体内常见的 6种醛类-DNA加合物的检测技术以及醛类-DNA加合物作为卷烟烟气暴露的生物标志物的研究进展,展望了同时检测多种 DNA加合物的研究方向及醛类-DNA加合物作为 DNA损伤标志物的研究前景。      

Determination of phosphorus status of wheat and barley crops using a rapid root bioassay

A root bioassay of soil P availability, based on the amount of ³²P-labelled phosphorus taken up in 15 min from a solution in the laboratory, has been tested on seedlings of winter wheat (Triticum aestivum L) and spring barley (Hordeum vulgare L). The seedlings were taken in spring from six different fertiliser plots, selected to give an extreme range of P availability, from the Broadbalk and Hoosfield experiments at Rothamsted. The results showed a negative relationship between the rate of phosphorus uptake and (a) the phosphorus contents of plants, and (b) Olsen's bicarbonate extractable phosphorus of the soils. This pattern is consistent with the results previously obtained when determining the phosphorus status of trees and grasses. This rapid bioassay procedure may therefore be applicable to agricultural crops.     

Aromatic DNA adducts in relation to dietary and other lifestyle factors in Spanish adults

The aim of this study was to assess the relationship between bulky DNA adducts in white blood cells (WBC) and lifestyle factors in a sample from the Spanish cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC). 296 subjects aged between 35 and 64 years, from five regions, were included. Food intake was estimated with a computerized version of dietary history questionnaire. Daily intake of polycyclic aromatic hydrocarbons (PAH) was estimated using a database with information on food content of potential carcinogens. Data on lifestyle and health factors were collected and DNA adducts measured using the nuclease P1 ³²P-postlabelling technique. Geometric means of adducts were similar for men and women (4.11/10⁹ and 3.94/10⁹ nucleotides, respectively). Highest levels of adduct were observed in non-smokers and non-occupationally exposed. Meat intake, oils and fats were associated with higher levels of adducts, but all non-statistically significant. Higher intakes of calcium, sodium and phosphorus were associated with lower adducts levels. Summarising, our study shows that bulky adducts measured by ³²P-postlabelling in DNA from WBC do not correlate with the usual diet of healthy Spanish adults. Although it has been proposed that diet be the main source of PAH in nonsmokers without occupational exposure, DNA adducts do not seem to be suitable biomarkers of dietary PAH in general population.     

不同类型烟草焦油致突变性的研究

通过对五种不同类型烟草（烤烟、晒黄烟、晒红烟、香料烟、白肋烟）焦油致突变性的研究表明，（１）对于烟草焦油来说，其致突变成分在引起鼠伤寒沙门氏菌回复突变方面是以移码型为主，且需要微粒体酶的激活，属于间接致突变物质。（２）不同类型间，焦油致突变性差异极显著，依次为烤烟＞晒黄烟≥晒红地≥香料烟＞白肋烟。（３）五种类型的不同品种间焦油致突变性表现不一致，其中烤烟、晒黄烟、香料烟的不同品种间焦油致突变性差异显著（极显著），而晒红烟、白肋烟的不同品种间差异不显著。     

Formation of 2-amino-α-carbolines in pan-fried poultry and 32P-postlabelling analysis of DNA adducts

 Amino-α-carbolines are food-derived genotoxic heterocyclic aromatic amines (HAAs) that have been shown to be carcinogenic in rodents, to induce preneoplastic foci in rat liver and to be active in a number of genotoxicity tests, inducing gene mutations, DNA strand breaks and cell transformation. 2-Amino-α-carboline (AαC) has been estimated to account for about 20% of the carcinogenic HAAs that are ingested with the diet. Using the tandem cartridge solid-phase extraction procedure we were able to show that in pan-fried poultry the proportion of AαC and its 3-methyl derivative (MeAαC) account for 15% of the HAA fraction. Covalent DNA adducts are considered to be the primary lesions in chemical carcinogenesis. Both AαC and MeAαC have been shown to induce covalent DNA adducts in vitro and in vivo. Formation of DNA adducts was investigated by ³²P-postlabelling analysis in vitro in primary rat hepatocytes treated with 10–500 μM AαC or MeAαC. While for MeAαC-derived adducts the highest response was obtained with the nuclease P1 enhancement procedure, AαC adducts were most efficiently detected upon ³²P-postlabelling preceded by a cartridge enrichment step. Adduct levels detected were dose dependent but decreased for the higher doses due to cytotoxic effects. We have characterised the major DNA adducts of AαC and MeAαC as deoxyguanosine derivatives with the amino-α-carboline bound via the 2-amino group to the C8 position of guanine. Received: 23 April 1998     

Effects of some technological processes on glucosinolate contents in cruciferous vegetables

Effects of blanching, boiling and freezing of selected cruciferous vegetables (Brussels sprouts, white and green cauliflower, broccoli, and curly cale) on their glucosinolate (GLS) contents were determined. It was found that blanching and cooking of the vegetables led to considerable (P < 0.05) losses of total GLS, from 2.7 to 30.0% and from 35.3 to 72.4%, respectively. No systematic changes in total GLS were found in the vegetables that were blanched and frozen for 48 h. In addition, the highest concentration of cancer-protective compounds, such as aliphatic and indole GLS, were found in Brussels sprouts (sinigrin and glucobrassicin) and in broccoli (glucoraphanin).     

Influence of pressure/temperature treatments on glucosinolate conversion in broccoli (Brassica oleraceae L. cv Italica) heads

Glucosinolates are a group of secondary plant metabolites that are found in the Brassicaceae family. Upon hydrolysis by the endogenous enzyme myrosinase, a large number of compounds can be formed of which some are potentially anticarcinogenic, while others are largely inactive. Furthermore, some bioactive compounds are unstable. Therefore, it is not only important to determine the type and amount of glucosinolates present or hydrolysed in a given plant, but it is also relevant to investigate the type of hydrolysis products. In this research, the effect of combined pressure–temperature treatments (100–500 MPa, 20–40 °C) on the glucosinolate conversion and the kind of hydrolysis products was studied in broccoli, both during treatment and after autolysis. The results, showed that high pressure can induce glucosinolate hydrolysis during treatment, promote the formation of isothiocyanates after treatment and that relatively more indole oligomers are formed during treatment than during autolysis. These results indicate that pressure treatment limits the loss of glucosinolates and its health beneficial products.