tailieunhanh - ECOTOXICOLOGY: A Comprehensive Treatment - Chapter 3

Hai chủ đề thường được khám phá trong triển lãm của các độc tố sinh hóa: bản chất của sự thay đổi sinh hóa và chế độ độc hại của hành động. So với bản chất của sự thay đổi, thay đổi sinh hóa chẳng hạn như những người liên quan đến monooxygenases cytochrome P450, metallothioneins, hoặc các protein căng thẳng được xem xét trong bối cảnh giải độc độc tố nói chung, hiện tượng hấp thụ. Các thay đổi khác như DNA adduct hình thành, sự ức chế enzyme, hoặc peroxy lipid có thể được xem như là bằng. | 3 Biochemistry of Toxicants All chemical pollutants must initially act by changing structural and or functional properties of molecules essential to cellular activities. Jagoe 1996 OVERVIEW Two themes are often explored in expositions of biochemical toxicology the nature of the biochemical change and the mode of toxic action. Relative to the nature of the change biochemical changes such as those associated with cytochrome P450 monooxygenases metallothioneins or stress proteins are considered in the context of general toxicant detoxification or sequestration phenomena. Other changes such as DNA adduct formation enzyme inhibition or lipid peroxidation might be viewed as evidence of a particular mode of action resulting in damage. Consequently toxicants sharing a common mode of action are discussed together such as the coplanar polychlorinated biphenyls PCBs dioxins and furans whose common mode of action involves the aryl hydrocarbon receptor Lucier et al. 1993 . The discussion here will adopt these organizing themes because doing so facilitates integration of the chapter s content with the rich mammalian toxicology literature that is similarly organized. But in keeping with the series emphasis on interlinking phenomena chapter topics will also be described in an information transfer context Figure and also Figure in Chapter 36 . The fields describing relevant levels of information transfer and complexity are genomics transcriptomics proteomics metabolomics bioenergetics or biochemical physiology molecular toxicology. All these areas of study explore different yet linked levels of organization relative to biological information flow and complexity. Genomics explores the entire nuclear DNA complement and variations within Toxicogenomics specifically focuses on the influence of toxicants on the nuclear DNA. The next level of the biochemical information flow emerges at transcription. Transcription initiation occurs when RNA polymerase attaches to .