污染胁迫下的分子生物标志物和分子诊断技术

    Biomarkers under pollution stress and their molecular diagnosis technology

    • 摘要: 在环境科学领域中,细胞和分子水平的生物标志物由于其特异性和实用性等优点,在近年来已经被广泛认可。传统的分子生物标志物,如超氧化物歧化酶(superoxide dismutase, SOD)、丙二醛(malonaldehyde, MDA)、8-羟基脱氧鸟苷(8-hydroxydeoxyguanosine, 8-OHdG)等,往往只能表征某类胁迫的程度,但却不能解释损伤和响应发生的分子机理,也不能精确地指示环境污染物的种类。新技术(高效液相色谱,气质联用,酶联免疫法等)的发展提升了传统分子生物标志物的检测灵敏度和特异性。为了加深对分子毒理学机理,筛选和确定新的分子生物标志物,一些新技术常着眼于提高筛选通量,提升可操作性和降低成本(如组学技术,单细胞凝胶电泳,报告生物体)。分子诊断的概念起初来源于临床诊断,转而被引入到环境科学研究中来,因为环境和人体一样是一个复杂的系统,环境污染可以看作一个复杂系统的疾病。为了更快更有效地筛选合适的生物标志物,需要广泛开展对模式生物的组学研究和致毒分子机制的研究。同时,也应注意研究过程中的标准化(如谨慎选择暴露浓度和时间,代表物种和其特定的生活史阶段)。

       

      Abstract: Abstract: Cellular and molecular biomarkers have been widely accepted in these years because of their strength of specific, monitoring and utilitarian. However, conventional biomarkers can only indicate the class of stress, but fail to explain why damage or response happens or, to indicate a specific pollutant. Thus, environmental monitoring and risk assessment are calling for utilitarian biomarkers and their measurement techniques. Recently, several studies have developed new techniques (e.g. high efficiency liquid chromatography and its mass spectrum, gas phase chromatography and its mass spectrum, enzyme-linked immunosorbent assay) for detecting molecular biomarkers, such as superoxide dismutase (SOD), malonaldehyde (MDA), 8-hydroxydeoxyguanosine (8-OhdG), etylcholinesterase (AchE), glutathione (GSH), heat shock proteins (HSPs), metallothionein(MT). Besides, many efforts focus on perfecting the extant techniques for easier operability or lower cost. We believe that techniques which are low-cost, or trace amount detectable or quickly and easily operative will be preferent in new biomarkers screening and validation. The screening, validation, and their evaluation methods need standardization before biomarkers are widely used in realistic environmental monitoring and management, because there is high diversity among different species and different exposure. In our opinion, for a certain pollutant, typical subject organisms in a specific period of its life history should be chosen and well studied the toxic response mechanisms induced by range concentrations and range exposure periods of toxic chemicals. Not only the extant biomarkers' research is in progress, but the new generation techniques, such as DNA chips, comet assay, bioreporter and omics methodology had emerged. They have offered a new sight to understand ecotoxicology, and powerful tools to explore new biomarkers. Omics and DNA chips may help to screen new responding gene specifically sensitive to a class of toxicants or particular one. The screening process is that: firstly prepare cDNA library derived from creatures exposed to pollutants, secondly analyze the differences of the mRNAs (genes) translation profile between blank control and treatments to summarize a specific responding profile for a particular pollutant, thirdly confirm and optimize the respond combination of genes in the field study. Comet assay is a promising and low-cost method to identify genotoxicants in the low level exposure. By using comet tail parameters, comet assay can determine the DNA damage of eukaryotes including human being. The standardized 96-well plate style comet assay kit allows scientists to detect numeric samples, especially for occupational health check. Bioreporters are the genetic modified organism, most of which are bacteria, and can monitoring environment risk outside the laboratory by fluorescence. Molecular biology has provided new strategies to explore and to study biomarkers. The intersection of molecular biology and environmental science can arise more and more promising knowledge and methodologies. The concept of molecular diagnosis was come up in the disease diagnosis area. However, it is also fit for environmental science, because pollutions are like diseases of the Mother Nature. Thus, the research frontiers, such as new strategies and techniques of disease molecular diagnosis are also very valuable for environmental monitoring and management.

       

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