PubMed HealthSearch

PubMed · 4428

Inhibition of dimethyl ether and methane oxidation in Methylococcus capsulatus and Methylosinus trichosporium.

Abstract

Metal-chelating or -binding agents inhibited the oxidation of dimethyl ether and methane, but not methanol, by cell suspensions of Methylococcus capsulatus and Methylosinus trichosporium. Evidence suggests that the involvement of metal-containing enzymatic systems in the initial step of oxidation of dimethyl ether and methane.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

R Patel, C T Hou, A Felix. 1976. Inhibition of dimethyl ether and methane oxidation in Methylococcus capsulatus and Methylosinus trichosporium.. https://doi.org/10.1128/jb.126.2.1017-1019.1976

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

The effect of iron limitation on expression of the aerobic and anaerobic electron transport pathway genes in Escherichia coli.

To determine whether the aerobic and anaerobic respiratory pathways of Escherichia coli are regulated in response to iron availability, strains containing lacZ reporter fusions to the cydAB, cyoABCDE, narGHJI, dmsABC and frdABCD operons were grown in medium limited for iron by use of the chelator, 2,2'-dipyridyl. Under anaerobic conditions, expression of the anaerobic respiratory pathway operons, narG-lacZ, dmsA-lacZ and frdA-lacZ, was reduced 14-16 fold when iron was limited. In contrast, expression of the aerobic pathway operons, cyoA-lacZ and cydA-lacZ, was elevated modestly. Iron-dependent transcriptional control of these operons was independent of the fur gene which encodes an iron-and-DNA-binding regulatory protein. The expression of fnr-lacZ was relatively unaffected by iron limitation suggesting that Fnr levels in the cell do not change in response to iron. The above findings suggest that in addition to Fur, some other cellular protein may bind iron for reporting and regulating iron-dependent cell functions.

2,2'-Dipyridyl

Transcriptional regulation of Mn-superoxide dismutase gene (sodA) of Escherichia coli is stimulated by DNA gyrase inhibitors.

The expression of manganese-containing superoxide dismutase (sodA) in Escherichia coli using sodA::lacZ gene fusion was found to be stimulated by DNA gyrase inhibitors, nalidixic acid, or coumermycin A1. Aerobically, the gyrase inhibitors increased the expression of sodA::lacZ in the presence or absence of either paraquat or the iron chelator 2,2'-dipyridyl. The concentrations of the inhibitors used were found to reduce DNA supercoiling. Treatment of wild-type cells (sodA+) with nalidixic acid increased the transcription of MnSOD mRNA. Anaerobically, the expression of sodA::lacZ in wild-type cells was not affected by nalidixic acid. However, nalidixic acid had a stimulatory effect on the anaerobic expression of sodA::lacZ in cells preinduced by the iron chelator as well as in mutants derepressed in sodA expression by virtue of their lacking the trans-acting repressor proteins or the cis-acting regulatory elements needed for sodA regulation. The results indicate that the effect of DNA gyrase inhibitors is secondary to the cis- and trans-regulatory elements of sodA and suggest that changes in DNA topology may affect transcriptional regulation of sodA.

2,2'-Dipyridyl

Ionizable groups linked to the reaction of 2,2'-dithiobispyridine with hemoglobin.

The pH-dependence of the second-order rate-constant for the reaction of 2,2'-dithiobispyridine with the CysF9(93) beta sulphydryl group of hemoglobin in the R quaternary structure is analyzed in terms of a tentative model based on the observation that this sulphydryl exists as a mixture of two tertiary conformations in dynamic equilibrium. For the four aquomethemoglobins studied (human A and S, dog and rabbit), the equation derived from this model gives a better fit than a simpler equation based on the assumption of only one tertiary conformation. For the corresponding carbonmonoxyhemoglobins the simpler equation gives a better fit. The dog and rabbit oxy and azidomet data are better fitted by the model equation, whereas the data for the corresponding human A and S derivatives are better fitted by the simpler equation. From the analysis pKa values of 6.1 and 8.7 are obtained for the ionization of groups coupled to the presumed conformational transition. The pKa of 6.1 is assigned to HisHC3(146) beta; the pKa of 8.7 is assigned to the CysF9(93) beta sulphydryl group in its external conformation. It is estimated that the pKa of this sulphydryl may be as high as 12.9 in its internal conformation.

2,2'-Dipyridyl