The mutagenic effect of ultraviolet radiation and nitrous acid on Mycobacterium phlei.
ABSTRACT Lethal and mutagenic effects of nitrous acid and UV radiation onMycobacterium phlei were studied Three auxotrophic strains of the PA strain ofMycobacterium phlei were obtained: ala-, his-, and gly- (ser-) INHr Bods of the his- strain grown in liquid media are longer to filamentous as compared with cells of the prototrophic PA strain grown in the
same media, whereas cells of the gly- (ser-) INHr mutant are shorter to coccobacillary. Cells of the ala- strain are characterized by their various length from normal to coccobacillary. The auxotrophic strains obtained differ from
each other by a frequency of spontaneous reversions to prototrophy. The his- strain is the most stable, a frequency of spontaneous reversions to prototrophy being 10-9. The gly- (ser-) INHr strain reverts spontaneously to prototrophy with a frequency of 10-8 to 10-7. The ala- strain spontaneously reverting with a frequency of 10-5 is the most labile. The auxotrophic mutants obtained do not differ from the original prototrophic strain in the other properties
A change in a frequency of INH and STM-resistant mutants was also studied. It was found that under the influence of UV radiation
a frequency of INH-resistant mutants increases 43 to 80 fold as compared with a frequency of spontaneous mutations, this latter
being about 2.6 × 10-6. No substantial increase in a frequency of STM-resistant mutants was found using UV irradiation under the given experimental
conditions; their spontaneous frequency equals to 9.0 × 10-9 to 2.0 X 10-8.
Article: Genetic transfers in Mycobacteria.[Show abstract] [Hide abstract]
ABSTRACT: Mycobacteria hold a special position among other bacterial genera, having a different composition of the cell wall, highly variable morphology of cells and colonies, specific growth properties, production of secondary metabolites etc. Mycobacteria are a group of microorganisms with a widerange of pathogenicity, varying from saprophytic to highly pathogenic species. Mycobacteria are a somewhat difficult model for studying genetic transfers, but they are important from the practical point of view as agents of serious human and animal diseases. In addition to slow growth, the main obstacle to genetic transfer studies in pathogenic mycobacteria is their cell wall. It is a barrier complicating the penetration of genetic material in both directions and its gentle disruption that would preserve the integrity of bacterial DNA is still a problem. Studies of genetic problems in mycobacteria started in the sixties when geneticists concentrated mainly on transformation, transduction, lysogeny and mutagenesis, in agreement with trends of work with other bacterial models. In spite of considerable effort knowledge of the genetics of mycobacteria is delayed as compared with other microbial models. However, even in mycobacteria a series of more or less successful attemps at genetic transfer between varieties of the same species or betwoen two representatives of different species have boon described. Nevertheless, moShods of genetic transfer have not yet been satisfactorily mastered and mutagenesis remains the main reliable means of at least a rough characterization of the myeobacterial genome. In the present communication we summarize the results obtained SO far. CO NJUGATIONFolia Microbiologica 02/1978; 23(2):140-51. · 0.79 Impact Factor
Article: Mycobacterium.Bacteriological reviews 04/1977; 41(1):217-372.
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ABSTRACT: This review summarizes the main results obtained in the fields of general and molecular microbiology and microbial genetics at the Institute of Microbiology of the Academy of Sciences of the Czech Republic (AS CR) [formerly Czechoslovak Academy of Sciences (CAS)] over more than 50 years. Contribution of the founder of the Institute, academician Ivan Málek, to the introduction of these topics into the scientific program of the Institute of Microbiology and to further development of these studies is also included.Journal of Industrial Microbiology 12/2010; 37(12):1227-39. · 1.80 Impact Factor