Jiri Konicek

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By using dimethyl sulfoxide or Tween 80 (1 or 0.2 %), the production ofl-lysine was increased by 20–28 and 23–25%, respectively, in regulatory mutant strains ofCorynebacterium glutamicum. The stimulation observed is supposed to be caused by influencing cellular surface structures.
Results obtained when studying conjugation in mycobacteria by means of different methods are summarized. The method of conjugation on surface of a solid complete medium was tested with different auxotrophic mutants of different strains ofMycobacterium smegmatis. It was not possible to obtain positive results even by means of the above method. This was(More)
The aim of the present work was to construct a replication map of the chromosome ofMycobacterium phlei. The method of mutagenesis of the replication point by means of nitrosoguanidine was applied to synchronously multiplying populations. Back mutations and forward mutations were induced m auxotrophic mutants PAmet and PAleu as well as in double auxotrophic(More)
It was the aim of the present work to construct the replication map of the chromosome ofMycobacterium phlei. The method of mutagenesis of the replication point by N-methyl-N-nitroso-N’-nitroguanidine in synchronously dividing populations and the method of analysis of gene frequency were applied. The order of replication of 19 genes on the chromosome was(More)
By second-step mutagenesis and treatment with N-methyl-N’-nitro-N-nitrosoguanidine a mutant strain ofMycobacterium sp. V-649 producing a glucan extracellular polymer and another new streptomycin-resistant mutant were prepared. This mutant strain formed more than 100% first-rate (1.0–1.2%) exocellular polysaccharide. Treatment with 1% dimethyl sulfoxide(More)
Results obtained when studying mutagenesis inMycobacterium phlei are summarized in this work. It was the aim of this paper to obtain an overall summary of mutation properties of this model in the selected genetic markers. Therefore, auxotrophic mutants, STM and INH resistant mutants and mutants with changed pigmentation induced by UV-radiation, ethyl(More)
A positive genetic transfer by protoplast fusion was obtained in auxotrophic mutantsBrevibacterium sp. M27his andBrevibacterium sp. M27arg. Transformation and protoplast fusion with liposomes (as genetic transfers in intact cells and their protoplasts by both the chromosomal and plasmid DNA) did not lead to transfer of the markers followed.
It is generally assumed that genetic research of mycobacteria is delayed as compared with other, more commonly used, bacterial models, particularly in the field of genetic transfers. In the field of mutagenesis the problems have been studied to such an extent that replication maps of the chromosome ofM. phlei andM. tuberculosis H37 Rv have already been(More)
Gene manipulation in mycobacteria developed in two phases. In the first phase genes of mycobacteria were transferred into cells ofE. coli andStreptomyces lividans. In the second phase, heterologous genes were transferred into mycobacteria either with a shuttle phasmid or hybrid plasmids. A prerequisite for successful gene manipulation in mycobacteria was a(More)
Production of the exocellular polysaccharide of the phytopathogenic bacteriumXanthomonas fuscans was investigated with respect to its possible use in utilization of industrial wastes containing lactose. Six stablelac + mutants were obtained after the treatment withN-methyl-N′-nitroso-N′-nitroguanidine. The mutants were compared with the parent strain.(More)