Uptake and genotoxicity of micromolar concentrations of cobalt chloride in mammalian cells

Literature data concerning the genotoxicity of cobalt salts have been conflicting. To establish appropriate incubation conditions, we conducted a series of uptake studies, before genotoxicity was determined by DNA strand break induction in HeLa cells and mutagenicity in V79 Chinese hamster cells. Co(II) is taken up by HeLa cells in a concentration‐dependent manner and is accumulated inside the cell. The uptake is preceded by a fast association step to the outer membrane, with no saturation up to 24 h. DNA strand breaks as determined by nucleoid sedimentation are induced at concentrations as low as 50μMCoCl₂. The induction is time‐dependent, showing the highest number of breaks after 4h incubation with no further increase up to 24h. CoCl₂ is mutagenic at the HPRT‐locus, enhancing the spontaneous mutation frequency 4.2‐fold at 100μ?. Besides direct interactions with DNA, the mutagenicity of CoCl₂ could also be due to a decrease in the Fidelity of DNA polymerisation.     

壬基酚、五氯酚及硝基苯对端足类河蜾蠃蜚(Corophium acherusicum)的毒性效应

为检测海洋中环境激素及芳烃类化合物对端足类生物的污染危害,实验选择端足类河蜾蠃蜚(Corophium acherusicum)为受试生物,研究了其在壬基酚、五氯酚、硝基苯三种有机污染物暴露下的96 h急性致死毒性效应和7 d慢性DNA损伤毒性效应。计算获得壬基酚、五氯酚和硝基苯对河蜾蠃蜚的96 h半致死浓度(LC50)分别为70、465、25 000μg·L-1,三种有机污染物对河蜾蠃蜚的毒性强弱顺序为壬基酚五氯酚硝基苯。运用碱解旋法检测壬基酚、五氯酚和硝基苯对河蜾蠃蜚DNA损伤的程度,计算得到7 d半效应浓度(EC50)分别为30、256、11 000μg·L-1。实验结果表明:三种有机污染物浓度的不断加大,引起河蜾蠃蜚DNA损伤程度的不断增加,呈显著的剂量-效应关系。     

北京市大气细颗粒物的遗传和非遗传毒性研究

用胞质阻断微核试验与单细胞凝胶电泳法检测北京市大气PM_2.5无机提取物与有机提取物对Balb/c 3T3细胞微核形成与DNA链断裂的影响;通过划痕染料示踪技术(SL/DT)观察PM_2.5无机提取物与有机提取物对Balb/c3T3细胞间通讯的影响.发现PM_2.5有机提取物可引起双核微核细胞率显著增加(P<0.01)及导致慧星细胞率和DNA迁移长度显著增加(P<0.01);PM_2.5有机提取物引起细胞间通讯的抑制; PM_2.5无机提取物未见明显毒作用.结果表明,PM_2.5可引起染色体损伤和原发性DNA损伤,抑制细胞间通讯,其毒作用主要由其有机成分引起.     

气态甲醛致小白鼠肝脏DNA-DNA交联的研究

为了探讨气态甲醛致生物体内DNA-DNA交联效应,进一步评价甲醛的遗传毒性作用,以昆明纯系小鼠为实验材料,进行了72 h动态吸入式连续染毒,采用荧光检测法检测甲醛染毒后小鼠肝细胞DNA-DNA交联形成的效应.实验结果表明,0.5 mg·m-3的气态甲醛能引起明显的DNA-DNA交联(p＜0.05),较高浓度的甲醛(1.0mg·m-3、3.0 mg·m-3,p＜0.01)可以产生极为明显的DNA-DNA交联作用.以上实验结果显示了0.5mg·m-3的气态甲醛就能致生物体内DNA-DNA交联效应,且随着浓度的升高DNA-DNA交联率越高.     

几株光合细菌的表型特征及DNA－NDA同源性分析

对５株新分离的光合细菌从形态、生理生化及ＤＮＡ－ＤＮＡ同源性等方面进行了研究．结果表明，菌株８与深红红螺菌（Ｐｈｏｄｏｓｐｉｒｉｌｌｕｍｒｕｂｒｕｍ）的模式菌株ＡＴＣＣ１１１７０的ＤＮＡ－ＤＮＡ同源性为９７％，菌株３７与沼泽红假单胞菌（Ｒｈｏｄｏｐｓｅｕｄｏｍｏｎａｓｐａｌｕｓｔｒｉｓ）的模式菌株ＡＴＣＣ１７００１的ＤＮＡ－ＤＮＡ同源性为８０％；菌株５５与球形红杆菌（Ｒｈｏｄｏｂａｃｔｅｒｓｐｈａｅｒｏｉｄｅｓ）的模式菌株ＡＴＣＣ１７０２３的ＤＮＡ－ＤＮＡ同源性为７１％；菌株４０和５２分别为另外两个ＤＮＡ同源群．根据各菌株形态、生理生化等表型特征以及ＤＮＡＧ＋Ｃｍｏｌ％和ＤＮＡ－ＤＮＡ同源性分析结果，确定了几株光合细菌的分类地位．     

Estimation of Aerobic Capacity and Determination of Its Associated Factors Among Male Workers of Industrial Sector of Iran

Introduction. The aim of this study was to estimate maximal aerobic capacity (V_O2max), to determine its associated factors among workers of industrial sector of Iran and to develop a regression equation for subjects’ V_O2max. Methods. In this study, 500 healthy male workers employed in Shiraz industries participated voluntarily. The subjects’ V_O2max was assessed with the ergocycle test according to the Åstrand protocol. Required data was collected with a questionnaire covering demographic details (i.e., age, job tenure, marital status, education, nature of work, shift work, smoking and weekly exercises). Results. The subject’s mean V_O2max was 2.69 ± 0.263 L/min. The results showed that there was an association between V_O2max and age, BMI, hours of exercise and smoking, but there was no association between V_O2max and height, weight, nature of work and working schedule. On the basis of the results, regression equations were developed to estimate V_O2max. Conclusion. Final regression equation developed in this study may be used to estimate V_O2max reliably without the need to use other laboratory instruments for aerobic measurement.     

北京市模拟给水管网管壁微生物膜群落分析

以北京市模拟给水管网管壁微生物膜为研究对象,采用HPC(异养菌平板计数)和PCR-SSCP(单链构象多态性)方法,分析模拟给水管网管壁微生物膜异养菌数目和微生物群落结构.结果表明,在相同流速条件下,镀锌钢管的管壁微生物数量约为PVC管的5倍.在相同材质的镀锌钢管内,死水区的HPC计数量约为0.6m·s-1,是流速区的1/5.计数结果的差异可能与不同材质表面的光滑度及流速造成微生物生长所需的氧气和营养基质不同有关.而不同材质和不同流速区微生物群落的SSCP电泳图谱则显示为一样,均在相同位置出现同样条带.测序结果显示, SSCP电泳图中的3条带与蜡状芽孢杆菌(Bacillus cereus, GenBank登录号为AB190077)、假单胞菌(Peudomonas sp.yged143, GenBank登录号为EF419342)和未分类细菌(Bacterium UASWS0134, GenBank登录号为DQ190347)的同源性分别为100%、99%和94%.测序结果的一致性可能与取样点为同一模拟管网,距离比较接近,不同微生物容易在其中流动和转移有关.而潜在致病菌蜡状芽孢杆菌和假单胞菌的存在则提示应该更加重视饮用水的微生物安全性.     

用于预应力筋长期实时应力监测的光纤传感测试技术研究

预应力筋是预应力混凝土结构中的关键受力构件,对其应力状态的监测具有重大意义。针对传统测试方法难以有效解决其应力分布测试问题的现状,提出基于光纤布拉格光栅传感测试技术的预应力筋长期实时应力监测方法。设计模拟张拉装置,并构建预应力钢筋的光纤光栅应变测试系统,进行模拟试验研究,其试验结果表明,该测试系统适合于预应力筋的工作环境,具有线性度高、重复性好,且不影响基体性能的特点。此外,针对预应力钢绞线的特殊结构和工作特点,提出具有温度补偿能力的锚端光纤布拉格光栅应力传感测试方案,并进行理论分析。研究结果验证了光纤光栅传感技术用于预应力筋应力测试的可行性,并为其实际工程应用奠定了基础。     

Effect of the chemical composition of organic extracts from environmental and industrial atmospheric samples on the genotoxicity of polycyclic aromatic hydrocarbons mixtures

Particulate organic matter (PM) present in the atmosphere is a complex mixture of chemicals like polycyclic aromatic hydrocarbons (PAH) that may exert adverse health effects including respiratory and cardiovascular disturbances and cancer. In this study, airborne samples from environmental or industrial areas exhibiting different physicochemical composition were compared for their capacities to induce DNA damage in human hepatocytes HepG2. DNA strand breaks and DNA adducts formed by benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE), the most reactive metabolite of the carcinogenic benzo[a]pyrene (B[a]P), were measured with the comet assay and by high-performance liquid chromatography (HPLC)/mass spectrometry, respectively. Cells were exposed to organic matter extracted from PM. Experiments were performed either at a constant concentration of B[a]P or at concentrations corresponding to fixed air volumes. Results show that industrial extracts tend to produce more benzo[a]pyrene diol epoxide-N ²-2′-deoxyguanosine (BPDE-N ²-dGuo) DNA adducts than strand breaks, whereas the opposite was observed with environmental extracts. The chemical composition of the extracts significantly impacts the nature and levels of DNA damage. The amount of B[a]P and interaction with other contaminants in the extracts need to be considered to explain the formation of DNA damage. These results emphasize the use of in vitro tests as promising and complementary tools to widely used toxic equivalent factor (TEF) approach in order to assess health hazards related to chemical exposure of the general population.     

Genotoxic potentials and related mechanisms of bisphenol A and other bisphenol compounds: A comparison study employing chicken DT40 cells

Bisphenol A (BPA) has been found in plastic food containers, paper currencies and toys. BPA has been reported for various adverse health concerns including reproduction, development and carcinogenesis. These potential health implications have led to increasing use of alternative bisphenols such as bisphenol F and bisphenol S among many. However, little is known about the toxicity of alternative bisphenols and most of the toxicological information is limited to endocrine disrupting potentials. In this study, we evaluated cytotoxicity and the genotoxic potentials of several bisphenol compounds, and identified the mechanism of genotoxicity using a panel of mutant chicken DT40 cell lines deficient in DNA repair pathways. Several bisphenols including bisphenol AP, bisphenol M, or bisphenol P exerted genotoxic potentials that are greater than that of BPA. Generally RAD54^−/− mutant cells were the most sensitive to all bisphenols except for bisphenol F, suggesting the induction of DNA double-strand breaks that could be rescued by homologous recombination. Genotoxic potential of bisphenols was confirmed by chromosomal aberration assay and γ-H2AX foci forming assay between wild-type and RAD54^−/− mutant. Among the tested bisphenols, BPP at 12.5 μM showed the greatest genotoxic potency, inducing chromosomal aberration and γ-H2AX foci in RAD54^−/− mutant by 2.6 and 4.8 folds greater than those in wild-type, respectively. Our results clearly show several alternative bisphenols can cause genotoxicity that could be rescued by homologous recombination pathway, and some bisphenols induced even greater genotoxic potentials than that of BPA.