Avoidance in Bacteria
Avoidance in Bacteria can bedetermined by MMR in vivo repair specification The analysis of current natural mutation dominant in the N-terminal portion of of lacIgene. Mutation InmutH, Mutl, ormutSstrains, of lacIforward The increased about 200-fold wild-type high-speed strain.In wild-type strain, velocity, comprises only 5% variation of the base frame But total mutation events, accounting for about 25% of the events of MMRdefective strain in the event of almost all of MMR deficiency in Strains occur in Monoran 5N. 8N mononucleotide will run in the MMR-deficient strain studies also frame specification … ¬ inversion, and shows a high level of instability nucleotide, poly (GT) plan. It is believed that MMR system, and is particularly important for repairing DNA polymerase event retardation simple sequence repeats, the system exhibits an affinity about 15 times for the restoration of the transition for base substitution in the middle transversion as well. Overall, ITIES E. coli MMR system, are consistent with those derived from the transformation experiments using double-stranded DNA molecule hetero and the Ed contradiction in vivo repair specification.
By eliminating the MMR system, it is in the development of a high mutation rate Were maintained under conditions for adjusting that was observed in bacterial cells The many generations that have concentrated the mutator, and be the result Selection process. For example, mutation if there is a de ¬] ED site The increased 100 fold in MMR-deficient cells, selection for mutations in this gene locus will Of the mutants that were selected, the concentration becomes 100 times the MMR deficient cells Population. In fact, the continuous selection of the direct multiple mutations Cell population obtained is made up in the MMR-deficient mutator mainly. In addition to to speed up the mutator phenotype and adjusting the generated Sequence differences that can require recombination barrier low-level I’m contributing to the differentiation process of the bacteria. Mutator phenotype of the thing It may be advantageous under conditions selective, there is no measurable negative electrode it Bacterial cells is a non-selective support for many generations, the effect of the above; Mutation load and strain the entire ¬ “-ness as much as possible.
Evolution of MMR-deficient mutator may be important for the emergence of bacterial pathogens that need fast in the laboratory under controlled conditions I will adapt to the new source. For example, more than 1% of Salmonella and E. coli bacteria has 30% of the infection green pus pus isolates in the lungs of cystic chronically strong mutator phenotype isolates of enterica | which is a sclerosis patients mutator. In addition, both of which are associated with a defect MMR of high-level phase change pathogenic meningitis. As mentioned above, the results of the phase deviation from the on / off framework mutations, and is elevated in the absence of functional MMR system significantly in mono 7C manner. Finally, it may be associated with mutations multistep process observation of bacteria requires the development of cancer in a mammal, or can serve as a model of the relationship between MMR defects, promotes the formation of tumors
Oxidative DNA damage is a source of mutations in living cells. All living organisms have evolved mechanisms to protect against oxidative damage, but little is known, such as Pseudomonas, the mechanism nonenteric bacteria thereof. You have examined the involvement of DNA protective enzymes in foil oxidized guanine repair enzymes to avoid mutations hunger Pseudomonas. In addition, we, involvement putida DNA polymerase V homolog RulAB stationary phase mutagenesis to investigate the possible connection between oxidative damage to DNA, and error-prone in the P.. Our results, Mutt GO repair enzymes MutY, and MutM has been shown to participate in the prevention of base substitution mutations at carbon starvation P. putida. Interestingly, the effect of antimutator dog is dependent on the growth phase of bacteria.
In spite of the lack of severe phenotype mutator that causes the dog of bacterial carbon starvation, twice only increased the effect on the rate of growth observed bacterial mutation. In cells dog actively growing well, this is an indication that you have a backup system to complement the lack of this enzyme. The knockout of MutM, is localization, has not changed the frequency spectrum of mutations in mutation. The DSS, to protect DNA from oxidative damage is known. DPS-defective P. putida cells found We are sensitive to abrupt exposure of hydrogen peroxide than the wild-type cells. At the same time, the absence of DPS does not affect the accumulation of mutations in a population of bacteria starvation. Therefore, only if the bacteria are exposed to external agents, leading to not to oxidative DNA damage of under physiological conditions, protective role of DPS is possible to be essential for the integrity of the genome is. Putida introduction of the Y-family DNA polymerase PolV rulAB homolog of P. Increase the percentage of base substitution of G between the mutation that occurs during the fasting state to B. Making a synthesis overcome past the bases the damaged DNA is PolV since known, our results could indicate that an important source of bacterial mutation hunger adenine oxidation products .
Bacteria, has spent most of the time in the starvation conditions in which their growth is suppressed by insufficient energy. However, the population of the stationary phase bacteria cause mutations, and have received rapid development. Mutagenesis that occurs in idle cell, is called mutation stationary phase or adaptive mutation. Bacteria has a stress response of some to provide a method that can mutation rate increases in stationary phase cells. The oxidative DNA damage is an important source of mutagenesis. This, 7,8 – dihydro -8 – the formation of oxo-2, that can lead to mutations in the -30 Lee · deoxyguanin stationary phase E. coli known. Further, the products of oxidative damage to adenine, to be mutagenic is shown. However, to date, interest is to obtain much oxidation products thereof.