Biomarkers under pollution stress and their molecular diagnosis technology

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.