SOS response

The question, of course, is that if the prokaryotic cells of the bacterium E. coli act in this way, under what circumstances will damaged or cancerous eukaryotic cells (animal or human cells) also act to repair themselves in the same manner  

Cancer-causing agents, or carcinogens, can induce an SOS response in bacteria, and cause mutations, and there is a strong correlation between mutagenesis and carcinogenesis (Voet and Voet, 1995, p. 1051). Further information is provided in the 

Among the previously unsuspected carcinogens found via the Ames test is the compound with the chemical name tn j -(2,3-dibromopropyl)phosphate, but commonly called Tris, as has been noted. Once used as a fire retardant on children s sleepwear, it unfortunately can be absorbed through the skin. Among other uses, it was even used in Japan as an antibacterial agent in food. 

The inferences are obvious. DNA genetic recombination can be a conduit for the formation and spread of cancerous cells. 

What is called DNA recombination repair is the replacement of a damaged segment of a DNA strand by a corresponding segment from an undamaged strand. In E. coli, at least, both these processes have been observed to be mediated or regulated by an enzyme (which is named RecA protein, and further identified as a 38-kDa nuclease). 

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Not appropriate. No enrichment occurs here, so the method is unlikely to pick up the very small numbers of organisms likely to be present in the soil. Medium A is also used, so response 1 also applies. 

On the other hand, comparative analysis of Fi variables gave the relative reduction of SOS-response in preincubated with AR bacterial cells (Table 3). So, repression SOS-response was proportionally to the length of the AR alkyl radical and was Fi = 3.7 (for Ce-AR) and Fi = 7.0 (for C12-AR) that 76.43-40.40 fold lower than the SOS-system activation level in cells exposured only by UV radiation. With reduction of the AR concentration to lO- M is still observed statistically significant differences in the values of induction index (Fi) of the control and experimental samples, although the repression of SOS-response was less expressed. An increase of the AR concentration up to 1(>3 M in the case of Ci-AR and C3-AR led to some suppression, and for the C5-, Ca- and C12-AR to increase the values of R. 

Tsvetkova, N., Golyasnaya, N. Induction of SOS-response in Escherichia coli under conditions of osmotic stress and in the presence of N-methyl-N -nitro-N-... 

Piddock, L. J. V., Walters, R. N., and Diver, J. M. (1990). Correlation ofquinolone MIC and inhibition ofDNA, RNA and protein synthesis and induction of the SOS response in Escherichia coli. Antimicrob. Agents Chemother. 34, 2331-2336. 

Figure 5.24 Activation of the host SOS response leads to lysis of a lysogenic cell.

Mutations in either recA or lexA can abolish the SOS-response and eliminate both W-reactivation and W-mutagenesis. These mutations also eliminate the mutability of the bacteria by UV-irradiation (16) The observation that UV mutagenesis depended on the SOS-response established that mutations were not inevitable outcomes of DNA damage and that DNA damage required processing by cellular mechanisms in order for mutations to be recovered. What specific processes regulated by the SOS-response are responsible for mutagenesis ... 

The SOS response is an inducible DNA-repair system that allows bacteria to survive rapid increases in DNA damage. Two proteins play a key role in... 

Flegrova, Z., Skarek, M., Bartos, T, Cupr, P. and Holoubek, I. (2007) Usefulness of three SOS-response tests for genotoxicity detection. Fresenius Environmental Bulletin, 16, 1369-1376. 

CA235 Obana, H., S. I. Nakamura, and R. I. Tanaka. Suppressive effects of coffee on the SOS responses induced by UV and chemical mutagens. Mutat Res 1986 175 47-50. 

PRB, Prophage, induction SOS response strand-breaks or cross-links. Salmonella typhimurium TAI525 pSK 1002... 

Muller, J. Janz, S. (1993) Modulation of the HnOn-induced SOS response in Escherichia coli PQ300 by amino acids, metal chelators, antioxidants, and scavengers of reactive oxygen species. Environ, mol. Mutag., 22, 157-163... 

Trichloroethane did not induced SOS response in the umu test using Salmo-... 

PRB, Prophage, induction, SOS response, strand-breaks or 666 Nakamura etal. (1987)... 

Regardless of the reality of these speculations (which will require significant additional experimentation to prove or disprove), it is clear that the addition of epigallocatechin gal-late to this system abolishes the induction of the SOS response. This strongly suggests that... 

Effect of various concentrations of epigallocatechin gallate on glabrene induction of the SOS response. 

Glabrene Quinones — - Enthusiastic — Cytoprotection- - DNA SOS Response Repair... 

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