The effect of NADH on the activity of the purified pyruvate dehydrogenase complexes (PDHc) of Enterococcus (Ec.) faecalis, Lactococcus lactis, Azotobacter vinelandii and Escherichia coli was determined in vitro. It was found that the PDHc of E. coli and L. lactis was active only at relatively low NADH/NAD ratios, whereas the PDHc of Ec. faecalis was inhibited only at high NADH/NAD ratios. The P...

Azotobacter vinelandii DJ71, which contains a mutation in the nifV gene, was derepressed for nitrogenase in the presence of homocitrate. When dinitrogenase was isolated from this culture, it was found to be identical to the wild-type dinitrogenase. However, when the same NifV- strain was derepressed in the presence of erythrofluorohomocitrate, a homocitrate analog which produces a nitrogenase w...

The properties of Azotobacter vinelandii deoxyribonucleic acid (DNA) and folded chromosomes were studied and compared to those of Escherichia coli as a standard. Based on melting temperature and buoyant density measurements, the guanosine + cytosine content of purified A. vinelandii DNA was 65%, whereas that of E. coli DNA was 50%. The results of renaturation studies showed that the unique DNA ...

CooA is a heme-containing transcriptional activator that enables Rhodospirillum rubrum to sense and grow on CO as a sole energy source. We have identified a number of CooA homologs through database searches, expressed these heterologously in Escherichia coli, and monitored their ability to respond to CO in vivo. Further in vitro analysis of two CooA homologs from Azotobacter vinelandii and Carb...

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Fragments of the Azotobacter vinelandii tetragonal surface (S) layer, free of outer membrane material, were obtained by treating whole cells with 100 microM EDTA. The three-dimensional structure of the S layer was reconstructed from tilted-view electron micrographs of the S-layer fragments, after computer-assisted image processing by correlation averaging. At a resolution of 1.7 nm, the S layer...

Blumberg, W. E. & Peisach, J. (1974) Arch. Biochem. Biophys. 162,502-512 Cammack, R. (1973) Biochem. Biophys. Res. Commun. 54,548-554 Cammack, R., Rao, K. K. & Hall, D. 0. (1971) Biochem. Biophys. Res. Commun. 44,s-14 Coffman, R. E. & Stavens, B. W. (1970) Biochem. Biophys. Res. Commun. 41,163-169 Fee, J. A. & Palmer, G. (1971) Biochim. Biophys. Actu 249,175-195 Genonde, Ic, Schlaak, M. E., Bri...

The high-potential 4Fe-4S* center ofAzotobacter vinelandii ferredoxin I has been titrated potentiometrically by a reductive procedure. The absorbance decrease at 510 nm accompanying the reduction of the high-potential center titrated with an Em of 320 mV (n = 1). The low-potential 4Fe-4S* center was titrated by using the absorbance decrease at 410 nm to monitor its reduction. This center exhibi...

background and objectives: azotobacter is a diazotroph bacterium reported to possess various plant growth-promoting characteristics.the aim of this study was to isolate azotobacter strains capable of fixing nitrogen and effectively hydrolyzing both organic and inorganic pi compounds. materials and methods: in this study, soil samples collected from a diverse range of slightly alkaline soil type...

Temperature affects the expression of the three different nitrogenases in Azotobacter vinelandii. Molybdenum repressed the vnfH and anfH operons relatively more at 30 degrees C than at 20 degrees C; at 14 degrees C molybdenum did not repress these genes at all. Similarly, V repressed the anf operon at 30 degrees C but not at 20 or 14 degrees C. Mo was poorly transported into cells grown at the ...