RESUMO
AECR mutants of Bacillus subtilis were obtained and analyzed. The mutants were characterized by derepression of aspartokinase II and diaminopimelate decarboxylase synthesis and the synthesis of the precursor of lysine--DAP. According to genetic mapping data, aec mutations are localized in some B. subtilis chromosomal regions; they are linked to the thr5, leuA8, lys21 markers.
Assuntos
Bacillus subtilis/genética , Proteínas de Bactérias , Cisteína/análogos & derivados , Mutação , Aspartato Quinase/antagonistas & inibidores , Aspartato Quinase/metabolismo , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/metabolismo , Carboxiliases/antagonistas & inibidores , Carboxiliases/metabolismo , Mapeamento Cromossômico , Cisteína/farmacologia , Ácido Diaminopimélico/metabolismo , Resistência Microbiana a Medicamentos , Ligação GenéticaRESUMO
Some Bacillus subtilis strains demonstrate a high degree of pHV14 and pP1251 plasmid integration into the chromosome (1.10(-1]. According to the data of genetical analysis the plasmids are integrated into several regions of the same chromosome. A significant plasmid amplification in the composition of chromosome is observed when breeding on an increasing chloramphenicol concentration (20-300 micrograms/ml). Both tandem repetitions and single plasmid DNA copies and their fragments are found in the bacterial chromosomal DNA.
Assuntos
Bacillus subtilis/genética , Cromossomos Bacterianos , DNA/genética , Amplificação de Genes , Plasmídeos , Recombinação Genética , Bacillus subtilis/efeitos dos fármacos , Cloranfenicol/farmacologia , Mapeamento Cromossômico , Marcadores Genéticos , Especificidade da Espécie , Transformação GenéticaRESUMO
The transformation of Bacillus subtilis Lys- strains with plasmid pLRS33 containing pBR322 and the Bac. subtilis chromosomal fragment carrying the genes for lysin biosynthesis and the riboflavin operon regulatory operator region (ribO) leads to the appearance of Rib- mutants. It was shown that these mutants contained long deletions covering a great portion of the riboflavin operon.
Assuntos
Bacillus subtilis/genética , Cromossomos Bacterianos/ultraestrutura , Mutação , Plasmídeos , Riboflavina/genética , Bacillus subtilis/metabolismo , Bacillus subtilis/ultraestrutura , Deleção Cromossômica , Cromossomos Bacterianos/metabolismo , DNA Bacteriano/genética , Lisina/genética , Óperon , Recombinação Genética , Mapeamento por Restrição , Riboflavina/biossíntese , Transformação BacterianaRESUMO
A number of B. subtilis mutants auxotrophic for lysine has been isolated and mapped in relation to the flanking ser2 marker. One of the mutants has been found to have a mutation in lys A gene coding for DAP-decarboxylase activity. The expression of DAP-decarboxylase is dependent on the product of lys R gene that is not linked with lysine genes cluster.
Assuntos
Bacillus subtilis/genética , Lisina/genética , MutaçãoRESUMO
DNA treated with thiophosphamide was studied for changes in its biological activity in transformation system of Bac. subtilis. DNA alkylation by this three-functional alkylating agent is shown to be followed by the reduction of transforming activity, changes in the competitive ability as well as by a decrease of the cotransfer coefficient for linked markers of transforming DNA. The observed changes in the transforming and cotransforming activities may be explained by variations in the DNA structure.
Assuntos
Bacillus subtilis/genética , DNA Bacteriano/genética , Tiotepa/farmacologia , Transformação Bacteriana/efeitos dos fármacos , Alquilação , Bacillus subtilis/efeitos dos fármacos , Cinética , Conformação de Ácido Nucleico/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
The SalI fragment of chromosomal DNA of Bacillus subtilis carrying the gene for lysine biosynthesis and the regulatory operator region (ribO) from the riboflavin gene was cloned into Escherichia coli cells. This fragment was shown to contain the gene coding for lysine synthesizing enzyme. Localization of this gene in Bac. subtili was determined. New plasmids pLRS33 and pLRB4 were constructed using pBR322; they carry a fragment homologous to pLP102 plasmid containing the operon for riboflavin biosynthesis.
Assuntos
Bacillus subtilis/genética , Clonagem Molecular/métodos , DNA Bacteriano/genética , Genes Bacterianos , Lisina/genética , Riboflavina/genética , Bacillus subtilis/metabolismo , Mapeamento Cromossômico , Escherichia coli/genética , Lisina/biossíntese , Mutação , Óperon , Plasmídeos , Riboflavina/biossíntese , Transformação BacterianaRESUMO
Hybrid plasmids pLRS33 and pLRB4 containing Bac. subtilis genes coding lysin biosynthesis were subjected to genetical analysis. It is shown that after pLRS33- and pLRB4- transformation of E. coli strains, auxotrophic relative to lysin and diaminopimelic acid, there occurs complementation of dapA, dapB, dapC, dapD, dapE, lysA mutations by plasmid pLRS33 and of dapC, dapB, lysA mutations by plasmid pLRB4. The plasmids are studied for their influence on the level of lysin and its precurror synthesis in E. coli strains.
Assuntos
Bacillus subtilis/genética , Escherichia coli/genética , Regulação da Expressão Gênica , Lisina/biossíntese , Bacillus subtilis/metabolismo , Escherichia coli/metabolismo , Genes Bacterianos , Lisina/genética , Plasmídeos , Transformação BacterianaRESUMO
A cell-free extract from blue-green alga Anacystis nidulans contains enzymes which repair in vitro the transforming activity of gamma-irradiated Bacillus subtilis DNA. The level of restoration of the transforming activity depends on the protein concentration in the reaction mixture, the duration of incubation and on the dose of irradiation. The repair of gamma-induced lesions is most efficient in the presence of magnesium ions, NAD and ATP. The present data indicate that the repair of transforming DNA is performed with the participation of DNA polymerase and polynucleotide ligase which function in the cell-free extract of algae.
Assuntos
Bacillus subtilis/efeitos dos fármacos , Cianobactérias/enzimologia , Reparo do DNA/efeitos dos fármacos , DNA Bacteriano/efeitos da radiação , Transformação Bacteriana/efeitos dos fármacos , Bacillus subtilis/genética , Bacillus subtilis/efeitos da radiação , Reparo do DNA/efeitos da radiação , Raios gama , Transformação Bacteriana/efeitos da radiaçãoRESUMO
Activities of riboflavinkinase and riboflavinsynthetase were measured in 15 strains of Bacillus subtilis with different genotype. The increased level of riboflavinkinase was observed in strains, resistant to lumiflavin or lumichrome. Specific activity of riboflavinkinase was found to be about 100 times lower than that of riboflavinsynthetase. The regulation of biosynthesis of these enzymes seems to proceed non-coordinately. This phenomenon can be the sequence of the existence of many operators, controlling the flavinogenesis in Bac. subtilis.
Assuntos
Bacillus subtilis/genética , Óperon , Fosfotransferases/genética , Riboflavina Sintase/genética , Riboflavina/biossíntese , Transferases/genética , Bacillus subtilis/metabolismo , Sistema Livre de Células , Relação Dose-Resposta a Droga , Ativação Enzimática , Flavina-Adenina Dinucleotídeo/biossíntese , GenótipoRESUMO
Regulatory markers of ribC group were located on the chromosome of Bacillus subtilis by means of genetic transformation using DNA isolated by the phenol-benzoate method of Kelly. Markers of this group controlling the regulation of riboflavin biosynthesis were mapped in the terminal region of the chromosome between phe and lys markers. A maximal value of contransfer index between ribC 1 and lys42 markers was found to be 3.5%.
Assuntos
Bacillus subtilis , Óperon , Riboflavina/biossíntese , Mapeamento CromossômicoRESUMO
Lumiflavin and lumichrome both inhibit the growth of different strains of Bacillus subtilis including riboflavin-constitutive mutant. Lumiflavin has no regulating effect, but lumichrome is an effector and it participates in the repression of riboflavin precursors synthesis and the synthesis of riboflavinsynthetase. Mutants resistant to lumiflavin or lumichrome accumulate a mixture of riboflavin, FMN and FAD. Their regulatory characteristics are substantially altered. They are repressed by higher concentrations of all effectors comparing with the wild type. The mapping of resistant mutants showed that the most of them are located near to ribC gene, probably inside of it. The simultaneous presence of all three flavins in the cultural medium shows that the regulatory protein is universal to the biosynthesis of all flavins.
