The Adaptive Response to Alkylation Damage

A weak adaptive response to alkylation damage in Salmonella typhimurium.

An efficient adaptive response to alkylation damage was observed in several enterobacterial species, including Klebsiella aerogenes, Shigella sonnei, Shigella boydii, Escherichia alkalescens, Escherichia hermanii, and Escherichia fergusonii. Increased O6-methylguanine-DNA and methylphosphotriester-DNA methyltransferase activities correlated with the induction of a 39-kDa protein recognized by m...

Regulatory responses of the adaptive response to alkylation damage: a simple regulon with complex regulatory features.

Oxidation of Methylhydrazines to Mutagenic Methylating Derivatives and Inducers of the Adaptive Response of Escherìchia coli to Alkylation Damage

The mrili) lliulr;t/ini"s. monomi lli>llmlra/inr, 1,1-dimethylhydrazinc, and 1,2-dimethyHiydrazinc, are known carcinogens but only weak mutagens in the Ames test. Chemical oxidation of these compounds by potassium fcrricyanide greatly enhanced their mutagenicity to an Escherichia coli atla mutant and converted them into inducers of the adaptive response of /•'. col! to alkylation damage. Knzy...

Oxidation of methylhydrazines to mutagenic methylating derivatives and inducers of the adaptive response of Escherichia coli to alkylation damage.

The methylhydrazines, monomethylhydrazine, 1,1-dimethylhydrazine, and 1,2-dimethylhydrazine, are known carcinogens but only weak mutagens in the Ames test. Chemical oxidation of these compounds by potassium ferricyanide greatly enhanced their mutagenicity to an Escherichia coli ada mutant and converted them into inducers of the adaptive response of E. coli to alkylation damage. Enzymatic oxidat...

Functional specialization of Chlamydomonas reinhardtii cytosolic thioredoxin h1 in the response to alkylation-induced DNA damage.

DNA damage occurs as a by-product of intrinsic cellular processes, like DNA replication, or as a consequence of exposure to genotoxic agents. Organisms have evolved multiple mechanisms to avoid, tolerate, or repair DNA lesions. To gain insight into these processes, we have isolated mutants hypersensitive to DNA-damaging agents in the green alga Chlamydomonas reinhardtii. One mutant, Ble-1, show...