209:. A key experiment that reveals the underlying mechanisms is that which involves the treatment with protein synthesis inhibitors to Oedogonium Chlamydomonas and Closterium cells. This experiment resulted in DNA-binding proteins being synthesized in the cells conditioned with the stressor. Furthermore, reverse adaptive response suggests that a high conditioning dose followed by a second low dose produces roughly the same magnitude of response. This could suggest that the mechanisms work by cellular response modulation, not prevention, to the impending damage. The adaptive response is not instantaneous and takes several hours to develop, however after development it can last for months given that the stressor exposure is limited and will not overwhelm the cell. This is known as being dose and time-dependent with a maximum response occurring at 4 hours after an initial conditioning dose of 100 cGy (centigray) radiation stressor.
66:
adaptive response. Since the adaptive response is able to prevent the possibility of different phenotypes it, therefore, allows organisms to minimize the stress effects it experiences from different stressors and eventually develop a resistance to the stressors. The effects of various chemical, biological, and physical genotoxic damaging agents jeopardize the genotypic integrity of all organisms; however, many evolutionary defense mechanisms have developed so that the stressors stimulate the adaptive response to reduce the stress to a more reasonable and manageable level and reduce genetic damage.
196:, and it is associated with DNA repair because this gene is able to repair lesions in phage DNA prior to infection. It has been also demonstrated that alkB is required for reactivation of MMS-treated (methylating agent methyl methanesulfonate) single-stranded phage and since there are no lesions to be removed, it has been suggested that alkBB is involved in replication of damaged template DNA. Also, the fact that alkB can confer resistance to a methylating agent it suggests that it functions by itself.
144:: Cys38 and Cys321. The Ada protein can repair damage by transferring methyl groups from O6-methylguanine or O4-methylthymine to Cys321 and also from methylphosphotriesters to Cys38 residue through an irreversible process. It can also convert the protein from a weak to a strong activator of transcription, increasing alkylation repair activity.
74:
mechanisms. This DNA up-regulation is involved in the adaptive response because the organism is being conditioned to protect itself against these stressors. Reactive oxygen species (ROS) are very damaging to DNA and highly associated with the adaptive response. When free radicals attack the important
69:
Many of these defense mechanisms have contributed to the nonspecific adaptive response by "conditioning" the effected organisms with small amounts of particular stressors to stimulate cellular conformation changes and increase the resistance when the organism is exposed to higher concentrations of
204:
Although little is known about the mechanism of the adaptive response, it is believed that changes in gene transcription and the activation of cellular defenses are involved. It has recently been suggested that specific mechanistic pathways of the adaptive response can active the important tumor
65:
Environmental influence plays a crucial role in the developmental plasticity of genotypes due to the introduction of DNA damaging agents. This phenomenon and the defense mechanism that has evolved to protect an organism’s genotype against damage and prevent multiple phenotypes is known as the
75:
biomolecules that makeup organisms, harmful molecular intermediates react with and damage DNA leading to base damage or breaks in the dsDNA strand. The adaptive response is helpful to prevent damage and maintain the integrity of the genome.
152:
The ada gene has regulatory and repair activities, both really close to each other. For the regulation to occur, the ada protein must be activated, which is a consequence of the DNA repair activity.
447:
He, Chuan; Hus, Jean-Christophe; Sun, Li Jing; Zhou, Pei; Norman, Derek P.G.; Dötsch, Volker; Wei, Hua; Gross, John D.; Lane, William S.; Wagner, Gerhard; Verdine, Gregory L. (October 2005).
23:
is a DNA damage response pathway prevalent across bacteria that protects DNA from damage by external agents or by errors during replication. It is initiated specifically against
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that particular stressor. For example, the decomposition of water produces highly reactive hydroxyl free radicals that can damage DNA, therefore, stimulating
254:"Biological stress response terminology: Integrating the concepts of adaptive response and preconditioning stress within a hormetic dose-response framework"
98:
57:, bacteria can adapt to the presence of the mutagen, rendering subsequent treatment with high doses of the same agent less effective.
329:
Widespread prevalence of a post-translational modification in activation of an essential bacterial DNA damage response
234:
Regulatory
Responses of the Adaptive Response to Alkylation Damage: a Simple Regulon with Complex Regulatory Features
326:
Kamat, Aditya; Tran, Ngat T.; Sharda, Mohak; Sontakke, Neha; Le, Tung B. K.; Badrinarayanan, Anjana (2023-10-10),
449:"A Methylation-Dependent Electrostatic Switch Controls DNA Repair and Transcriptional Activation by E. coli Ada"
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that can repair a variety of lesions, removing a base from the sugar-phosphate backbone, producing an
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51:
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Calabrese EJ, Bachmann KA, Bailer AJ, Bolger PM, Borak J, Cai L, et al. (July 2007).
111:
233:
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Crystal structures of catalytic complexes of the oxidative DNA/RNA repair enzyme AlkB.
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383:
366:
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adaptive response to alkylating agents is a flavin-containing, DNA-binding protein.
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177:
465:
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28:
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269:
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transfers methylation damage from DNA to one of its two active methyl acceptor
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141:
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Yu B, Edstrom WC, Benach J, Hamuro Y, Weber PC, Gibney BR, Hunt JF. (2006).
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43:
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393:
425:
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Rohankhedkar MS, Mulrooney SB, Wedemeyer WJ, Hausinger RP. (2006).
367:"Adaptive response: some underlying mechanisms and open questions"
189:
105:
206:
115:, each one working in specific residues, all regulated by the
47:
479:
Sedgwick, B., Robins, P., Totty, Nick., Lindahl, Tomas.
50:. Under sustained exposure to low-level treatment with
481:
Functional
Domains and Methyl Acceptor Sites of the
410:"A new pathway for DNA repair in Escherichia coli"
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226:
224:
222:
360:
358:
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8:
365:Dimova EG, Bryant PE, Chankova SG (2008).
91:adaptive response constitutes four genes:
46:groups on the sugar-phosphate backbone of
464:
392:
382:
301:
299:
297:
295:
408:Samson, Leona; Cairns, John (May 1977).
218:
83:This response was first identified in
129:adaptive response is mediated by the
7:
247:
245:
258:Toxicology and Applied Pharmacology
14:
487:v. 263. n 9. p 4430-4433, 1998.
384:10.1590/S1415-47572008000300002
232:Landini, P, Volkert MR. (2000)
371:Genetics and Molecular Biology
1:
466:10.1016/j.molcel.2005.08.013
16:Cellular activity in E. coli
160:The alkA gene product is a
561:
498:The AidB component of the
270:10.1016/j.taap.2007.02.015
338:10.1101/2023.10.09.561495
79:The E. coli Ada response
176:The aidB product is a
311:to alkylation damage.
307:Adaptive response of
180:-containing protein.
305:Volkert MR. (1988).
314:Environ Mol Mutagen
239:182(23): 6543–6549.
205:suppressor protein
523:439(7078):879-84.
420:(5608): 281–283.
21:adaptive response
552:
524:
514:
508:
500:Escherichia coli
494:
488:
483:Escherichia coli
477:
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426:10.1038/267281a0
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309:Escherichia coli
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545:Gene expression
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507:188(1):223-30.
489:
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453:Molecular Cell
439:
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377:(2): 396–408.
348:
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217:
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214:
211:
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194:oxidoreductase
185:
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485:Ada Protein*.
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316:11(2):241-55.
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237:J. Bacteriol.
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264:(1): 122–8.
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505:J Bacteriol
192:-dependent
188:alkB is an
166:abasic site
162:glycosylase
131:Ada protein
40:nucleotides
29:methylation
540:DNA repair
534:Categories
394:10023/3327
343:2024-02-28
213:References
135:covalently
72:DNA repair
52:alkylating
25:alkylation
434:1476-4687
200:Mechanism
122:protein.
44:phosphate
278:17459441
142:residues
139:cysteine
133:, which
61:Function
55:mutagens
286:1947211
127:E. coli
117:E. coli
89:E. coli
87:. The
85:E. coli
37:thymine
33:guanine
521:Nature
432:
414:Nature
284:
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178:flavin
109:, and
282:S2CID
31:, of
430:ISSN
274:PMID
190:iron
184:alkB
172:aidB
156:alkA
125:The
112:aidB
106:alkB
100:alkA
19:The
461:doi
422:doi
418:267
389:hdl
379:doi
334:doi
266:doi
262:222
207:p53
148:Ada
120:Ada
94:ada
48:DNA
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