title: Agents of mycobacterial variations.
abstract: Mycobacterial variations are determined by physicochemical agents or by genetic transfers. The pioneer work done on the study of the effects of light, radiation, heat, nutritional factors, and drugs is reviewed. Technical and conceptual problems arise in the study of genetic transfer by means of conjugation and transformation in mycobacteria. Transduction and lysogenic conversion are shown to be responsible for important changes in bacterial and colony morphology, enzymatic activities, bacteriophage and drug resistance. Results of recent experiments with different strains of bacille Calmette-Guérin (BCG) suggest a relationship between phage conversion and the degree of immunogenic potential.
mesh_terms: D003227:Conjugation, Genetic; D004352:Drug Resistance, Microbial; D014644:Genetic Variation; D008242:Lysogeny; D009154:Mutation; D009161:Mycobacterium / Q000187:drug effects / Q000235:genetics* / Q000276:immunology; D014161:Transduction, Genetic