Main description:

Concern is often expressed that our environment may include an increasingly large variety of mutagens, but the extent of the potential hazard they pose has yet to be fully evaluated. A variety of empirical procedures has been devised with which to estimate the mutagenic potency of suspect agents, and the relative merits of different tests are currently under debate. Although such tests are of great value, and are indeed indispensable, they are not, nevertheless, sufficient. In the long term, accurate estimation of hazard will also require a better understanding of the various mechanisms of mutagenesis, and in many instances these remain remarkably elusive. Our knowledge and appreciation of the problem has increased substantially over the last few years, but the precise way in which many mutagens cause mutations is not yet known. The aims of this conference were therefore two-fold. The first was to survey present information about mutagenic mechanisms, drawing together data from work with various experimental approaches and organisms, in order to discern the principles governing the action of different mutagens. The second was to examine the implications of such principles for the execution and evaluation of test procedures, and critically assess the research areas that need further attention in order to improve the interpretation of test results. Chris Lawrence v ACKNOWLEDGEMENT We gratefully acknowledge the support provided for this Conference by the U.,S. Department of Energy, The Foundation for Microbiology, Exxon Corporation and the University of Rochester.

Contents:

Session I: Mutagen/DNA Interactions.- Mutagenic effects of nucleic acid modification and repair assessed by in vitro transcription.- Genetic effects of bisulfite: Implications for environmental protection.- Session II: Infidelity and Specificity.- Infidelity of DNA replication as a basis of mutagenesis.- The specificity of infidelity of DNA polymerase.- Replication and mutagenesis of irradiated single-strand phage DNA.- Mutational specificity of UV light: Influence of excision repair and the mutator plasmid pKM101.- Session III: Genetic Analysis of Mutagenesis.- Regulation and function of cellular gene products involved in UV and chemical mutagenesis in E. coli.- Differential sensitivity to certain DNA-damaging treatments, including 8-methoxypsoralen plus 340nm ultraviolet irradiation, between K-12 and B/r strains of Escherichia coli.- The use of DNA-repair deficient mutants of Chinese Hamster ovary cells in studying mutagenesis mechanisms and in testing for environmental mutagens.- Session IV: Mammalian Systems.- Variation in response to mutagens amongst normal and repair-defective human cells.- Relationship between excision repair and the cytotoxic and mutagenic action of chemicals and UV radiation.- The induction of resistance to alkylation damage in mammalian cells.- Induced mutagenesis of simian virus 40 infecting carcinogen-treated monkey cells.- Session V: Human Systems and Environmental Protection.- Analysis of chemically induced mutation in single cell populations.- Adaptability of microbial mutagenicity assays to the study of problems of environmental concern.- Final Discussion.- Participants.