scholarly journals Bacterial DNA repair genes and their eukaryotic homologues: 3. AlkB dioxygenase and Ada methyltransferase in the direct repair of alkylated DNA.

2007 ◽  
Vol 54 (3) ◽  
pp. 459-468 ◽  
Author(s):  
Jadwiga Nieminuszczy ◽  
Elzbieta Grzesiuk
Keyword(s):  
Adaptive Response ◽  
Alkylating Agents ◽  
Mechanisms Of Action ◽  
Dna Bases ◽  
Mutagenic Action ◽  
Bacterial Dna ◽  
E Coli ◽  
Sublethal Doses ◽  
Ada Protein ◽  
Repair Genes

Environmental and endogenous alkylating agents generate cytotoxic and mutagenic lesions in DNA. Exposure of prokaryotic cells to sublethal doses of DNA alkylating agents induces so called adaptive response (Ada response) involving the expression of a set of genes which allows the cells to tolerate the toxic and mutagenic action of such agents. The Ada response includes the expression of four genes: ada, alkA, alkB, and aidB. The product of ada gene, Ada protein, is an activator of transcription of all four genes. DNA bases damaged by alkylation are removed by distinct strategies. The most toxic lesion 3meA is removed by specific DNA glycosylase initiating base excising repair. The toxic and mutagenic O6meG is repaired directly by methyltransferases. 1meA and 3meC are corrected by AlkB DNA dioxygenase. The mechanisms of action of E. coli AlkB dioxygenase and its human homologs ABH2 and ABH3 are described in more details.

scholarly journals Ada protein– and sequence context–dependent mutagenesis of alkyl phosphotriester lesions in Escherichia coli cells

2020 ◽  
Vol 295 (26) ◽  
pp. 8775-8783
Author(s):  
Jiabin Wu ◽  
Jun Yuan ◽  
Nathan E. Price ◽  
Yinsheng Wang
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Adaptive Response ◽  
Dna Polymerases ◽  
Replication Machinery ◽  
Sequence Context ◽  
E Coli ◽  
Highly Efficient ◽  
Escherichia Coli Cells ◽  
Ada Protein

Alkyl phosphotriester (alkyl-PTE) lesions are frequently induced in DNA and are resistant to repair. Here, we synthesized and characterized methyl (Me)- and n-butyl (nBu)-PTEs in two diastereomeric configurations (Sp and Rp) at six different flanking dinucleotide sites, i.e. XT and TX (X = A, C, or G), and assessed how these lesions impact DNA replication in Escherichia coli cells. When single-stranded vectors contained an Sp-Me-PTE in the sequence contexts of 5′-AT-3′, 5′-CT-3′, or 5′-GT-3′, DNA replication was highly efficient and the replication products for all three sequence contexts contained 85–90% AT and 5–10% TG. Thus, the replication outcome was largely independent of the identity of the 5′ nucleotide adjacent to an Sp-Me-PTE. Furthermore, replication across these lesions was not dependent on the activities of DNA polymerases II, IV, or V; Ada, a protein involved in adaptive response and repair of Sp-Me-PTE in E. coli, however, was essential for the generation of the mutagenic products. Additionally, the Rp diastereomer of Me-PTEs at XT sites and both diastereomers of Me-PTEs at TX sites exhibited error-free replication bypass. Moreover, Sp-nBu-PTEs at XT sites did not strongly impede DNA replication, and other nBu-PTEs displayed moderate blockage effects, with none of them being mutagenic. Taken together, these findings provide in-depth understanding of how alkyl-PTE lesions are recognized by the DNA replication machinery in prokaryotic cells and reveal that Ada contributes to mutagenesis of Sp-Me-PTEs in E. coli.

Quasi-adaptive response to alkylating agents and Ada-protein functions in Escherichia coli

2008 ◽  
Vol 44 (1) ◽  
pp. 21-26
Author(s):  
S. V. Vasilieva ◽  
E. Yu. Moshkovskaya ◽  
A. S. Terekhov ◽  
V. D. Mikoyan ◽  
A. F. Vanin
Keyword(s):  
Escherichia Coli ◽  
Adaptive Response ◽  
Alkylating Agents ◽  
Protein Functions ◽  
Ada Protein

Exposure of E. coli to nitrosocimetidine induces the adaptive response to alkylating agents

1984 ◽  
Vol 139 (3) ◽  
pp. 111-114 ◽  
Author(s):  
A.J. Alldrick ◽  
I.R. Rowland ◽  
S.D. Gangolli
Keyword(s):  
Adaptive Response ◽  
Alkylating Agents ◽  
E Coli

scholarly journals Alkylating agents induce UVM, a recA-independent inducible mutagenic phenomenon in Escherichia coli.

Genetics ◽  
1995 ◽  
Vol 141 (3) ◽  
pp. 813-823 ◽  
Author(s):  
G Wang ◽  
V A Palejwala ◽  
P M Dunman ◽  
D H Aviv ◽  
H S Murphy ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Adaptive Response ◽  
Transfection Efficiency ◽  
Alkylating Agents ◽  
Dna Lesions ◽  
Noncoding Dna ◽  
E Coli ◽  
Sos Induction ◽  
Cell Pretreatment ◽  
A Site

Abstract Noninstructive DNA damage in Escherichia coli induces SOS functions hypothesized to be required for mutagenesis and translesion DNA synthesis at noncoding DNA lesions. We have recently demonstrated that in E. coli cells incapable of SOS induction, prior UV-irradiation nevertheless strongly enhances mutagenesis at a noninstructive lesion borne on M13 DNA. Here, we address the question whether this effect, named UVM for UV modulation of mutagenesis, can be induced by other DNA damaging agents. Exponentially growing delta recA cells were pretreated with alkylating agents before transfection with M13 single-stranded DNA bearing a site-specific ethenocytosine residue. Effect of cell pretreatment on survival of the transfected DNA was determined as transfection efficiency. Mutagenesis at the ethenocytosine site in pretreated or untreated cells was analyzed by multiplex DNA sequencing, a phenotype-independent technology. Our data show that 1-methyl-3-nitro-1-nitrosoguanidine, N-nitroso-N-methylurea and dimethylsulfate, but not methyl iodide, are potent inducers of UVM. Because alkylating agents induce the adaptive response to defend against DNA alkylation, we asked if the genes constituting the adaptive response are required for UVM. Our data show that MNNG induction of UVM is independent of ada, alkA and alkB genes and define UVM as an inducible mutagenic phenomenon distinct from the E. coli adaptive and SOS responses.

Quality Improvement of the DNA extracted by boiling method in Gram negative bacteria

2017 ◽  
Vol 6 (04) ◽  
pp. 5347 ◽  
Author(s):  
Omar B. Ahmed* ◽  
Anas S. Dablool
Keyword(s):  
Dna Extraction ◽  
Control Method ◽  
Extraction Procedure ◽  
Cost Effective ◽  
High Yield ◽  
Gram Negative Bacteria ◽  
Bacterial Dna ◽  
Gram Negative ◽  
E Coli

Several methods of Deoxyribonucleic acid (DNA) extraction have been applied to extract bacterial DNA. The amount and the quality of the DNA obtained for each one of those methods are variable. The study aimed to evaluate bacterial DNA extraction using conventional boiling method followed by alcohol precipitation. DNA extraction from Gram negative bacilli was extracted and precipitated using boiling method with further precipitation by ethanol. The extraction procedure performed using the boiling method resulted in high DNA yields for both E. coli and K. pneumoniae bacteria in (199.7 and 285.7μg/ml, respectively) which was close to control method (229.3 and 440.3μg/ml). It was concluded that after alcohol precipitation boiling procedure was easy, cost-effective, and applicable for high-yield quality of DNA in Gram-negative bacteria.

scholarly journals A polymeric approach toward resistance-resistant antimicrobial agent with dual-selective mechanisms of action

2021 ◽  
Vol 7 (5) ◽  
pp. eabc9917
Author(s):  
Silei Bai ◽  
Jianxue Wang ◽  
Kailing Yang ◽  
Cailing Zhou ◽  
Yangfan Xu ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Mechanisms Of Action ◽  
Model Systems ◽  
General Strategy ◽  
Antimicrobial Polymers ◽  
Bacterial Dna ◽  
Bacterial Membranes ◽  
Severe Infections ◽  
Multiple Drugs ◽  
Resistance Rates

Antibiotic resistance is now a major threat to human health, and one approach to combating this threat is to develop resistance-resistant antibiotics. Synthetic antimicrobial polymers are generally resistance resistant, having good activity with low resistance rates but usually with low therapeutic indices. Here, we report our solution to this problem by introducing dual-selective mechanisms of action to a short amidine-rich polymer, which can simultaneously disrupt bacterial membranes and bind to bacterial DNA. The oligoamidine shows unobservable resistance generation but high therapeutic indices against many bacterial types, such as ESKAPE strains and clinical isolates resistant to multiple drugs, including colistin. The oligomer exhibited excellent effectiveness in various model systems, killing extracellular or intracellular bacteria in the presence of mammalian cells, removing all bacteria from Caenorhabditis elegans, and rescuing mice with severe infections. This “dual mechanisms of action” approach may be a general strategy for future development of antimicrobial polymers.

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