Effects of DNA-damaging Agents on Aerobic Methylobacteria Capable and Incapable of Utilizing Dichloromethane

Abstract

Methylobacterium dichloromethanicum DM4, a degrader of dichloromethane (DCM), was more tolerant to the effect of H 2 O 2 and UV irradiation than Methylobacterium extorquens AM1, which does not consume DCM. The addition of CH 2 Cl 2 to methylobacteria with active serine, ribulose monophosphate, and ribulose bisphosphate pathways of C 1 metabolism, grown on methanol, resulted in a 1.1-to 2.5-fold increase in the incorporation of [ α -32 P]dATP into DNA by the Klenow fragment (exo -). Since DCM dehalogenase was not induced in this process, the increase in the total lengths of DNA gaps resulted from the action of DCM rather than S -chloromethylglutathione (intermediate of primary dehalogenation). The degree of DNA damage in the presence of CH 2 Cl 2 was lower in DCM degraders than methylobacteria incapable of degrading this pollutant. This suggests that DCM degraders possess a more efficient mechanism of DNA repair.

Aerobic methylobacteria as the basis for a biosensor for dichloromethane detection

“…Miniature FTs are often used as electrochemical transformers of biosensor sig nals for the detection of various toxic compounds, e.g., pesticides (atrazine [17] and 2,4 D [18]) and toxins (β bungarotoxin from the venom of the snake Bun garus multicinctus [19]). FTs containing alcoholoxi dase and cells of the methylotrophic yeast Hansenula polymorpha are known to be applied for formaldehyde detection [20]. FTs are also known to be used for dichloromethane detection.…”

Chloride‐associated adaptive response in aerobic methylotrophic dichloromethane‐utilising bacteria

“…extorquens AM1 to grow with DCM, when provided with dcmA functionally expressed from a plasmid [12], suggest that other proteins and genes are likely to be involved in growth with DCM. To date, microbial adaptive mechanisms to DCM remain to be elucidated, although it is clear that DCM-consuming bacteria excrete the protons and chloride anions produced by dehalogenation into the extracellular medium [5,7].…”