Selective mutagenicity

That such possibilities exist for selective mutagenicity is excellent news for all who are concerned by the steady increase in agent-resistance among uneconomic species. 

Fig. 9. Mutagenesis by a synthetic oligonucleotide of a cloned sequence available in single-stranded form (a) single-stranded M13 template containing uracil (U) residues (b) double-stranded product, uracil residues are not mutagenic (c) strong selection for M13 phages containing mutation of interest (23).

Extensive pharmacology Mutagenicity Structural optimization Backup compounds Optimal agent selection... 

The choice of the strain of microorganism is one of the important variables in the process. The strains to be used in manufacture are mutants of the original producer, which are chosen as the result of a planned program of mutant selection. Sometimes a spontaneous mutation occurs usually, it is induced by mutagenic agents or irradiation of various sorts. The choice of the best strain depends on its abiUty to produce large amounts of the proper antibiotic in a reasonable time from ingredients that are economically feasible (73). 

NCI. 1968. Evaluation of carcinogenic, teratogenic and mutagenic activities of selected pesticides and industrial chemicals. Volume I Carcinogenic study. Prepared by Bionetics Research Labs, Inc., Bethesda, MD National Cancer Institute. NCI-DCCP-CG-1973-1-1. 

From this one ancestral fungus each penicillin manufacturer has evolved a particular production strain by a series of mutagenic treatments, each followed by the selection of improved variants. These selected variants have proved capable of producing amounts of penicillin far greater than those produced by the wild strain, especially when fermented on media under particular control conditions developed in parallel with the strains. These strain selection procedures have become a fundamental feature of industrial biotechnology. 

Singh HB, Salas LJ, Stiles RE. 1982. Distribution of selected gaseous organic mutagens and suspect carcinogens in ambient air. Environmental Science and Technology 16 872-880. 

Eleven plant species (Table 3) were preliminarly tested for their response to the Feulgen staining method (described below), which is essential for the efficient microscope observation of genetic anomalies of cells. This, in order to select plants to be successively used in the experiments with the mutagenic compounds. 

Negative results for mutagenicity of d.v-chlordanc and tran.v-chlordanc were reported in various strains of bacteria and in hepatocyte cultures of small mammals. But technical chlordane proved mutagenic to selected strains of Salmonella typhimurium and induced gene conversions in certain strains of the yeast, Saccharomyces cervisiae (IARC 1979 USEPA 1980, 1988 WHO 1984). 

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