Upon encystment induction, Azotobacter vinelandii produces the phenolic lipids alkylresorcinols (ARs) that are structural components of the cysts. The enzymes responsible for the ARs synthesis are encoded in the arsABCD operon, whose expression is activated by ArpR. The transcription of arpR is initiated from an RpoS dependent promoter. The nitrogen-related phosphotransferase system (PTS(Ntr)) ...

Bacterial ferritin from Azotobacter vinelandii (AvBFJ has a function in H2 uptake. The Fe3+ reduction on the surface of the iron core from AvBF0 is accompanied simultaneously by H2 uptake, with a maximum activity of H2 uptake of 450 H2/AvBF0. A reduction potential of -402 mV for iron reduction on the surface of the core is found. A shift to the red the protein absorbance peaks ranging from 280 ...

After synthesis during the early log phase, the concentrations of ubiquinone and cytochromes did not vary during the growth cycle of Azotobacter vinelandii, when grown with either high or low aeration on nitrogen-free or urea-containing media. The level of aeration had no effect on the concentrations of the electron carriers synthesized, but affected the growth rate. On urea-containing medium, ...

Azotobacter vinelandii OP was grown to stationary phase in defined medium. The cell-free culture medium was analyzed for cytokinin content by XAD-2 and Sephadex LH-20 chromatography, thin-layer chromatography, tobacco callus bioassay, and enzyme immunoassay. Three cytokinin-active fractions were detected and tentatively identified as trans-zeatin, isopentenyladenosine, and isopentenyladenine. T...

Protein turnover occurs during differentiation of Azotobacter vinelandii 12837 to the extent of 50% during encystment and 7% during germination. The addition of rifampin at the initiation of encystment prevents encystment and inhibits turnover. In germinating cysts, protein turnover is essential owing to an apparent lack of certain amino acid biosynthetic enzymes. The capacity to synthesize sul...

Biological N2 fixation, the reduction of N2 to NH 3 , is catalyzed by the enzyme nitrogenase . Fractionation studies of nitrogenases from a variety of organisms have shown that all are composed of two similar proteins, one contains Mo and Fe and is called the Mo-Fe protein and the other contains only Fe and is called the Fe protein . Recently homogeneous preparations of these proteins from Azot...

Nitrogen fixation in Azotobacter vinelandii is regulated by the nifLA operon. NifA activates the transcription of nif genes, while NifL antagonizes the transcriptional activator NifA in response to fixed nitrogen and molecular oxygen levels. However, transcriptional regulation of the nifLA operon of A. vinelandii itself is not fully understood. Using the S1 nuclease assay, we mapped the transcr...

Mutants of Azotobacter vinelandii that fix N(2) in the presence of excess NH(4) (+) have been isolated. A mutant that was unable to synthesize component I and component II of nitrogenase was spontaneously reverted to the N(2)-fixing phenotype. Of 21 revertants picked, 7 revertants were not as sensitive as the wild type to repression. A derepressed mutant is as sensitive as the wild type to grow...

Examination of interactions among various substrates and inhibitors reacting with a partially purified nitrogenase from Azotobacter vinelandii has shown that: nitrous oxide is competitive with N2; carbon monixide and acetylene are noncompetitive with N2; carbon monoxide, cyanide, and nitrous oxide are noncompetitive with acetylene, whereas N2 is competitive with acetylene; carbon monoxide is no...

Previous research has demonstrated that production of natural fiber reinforced thermoplastic composites (NFRTCs) utilizing bacterially-derived pure polyhydroxybutyrate (PHB) does not yield a product that is cost competitive with synthetic plastic-based NFRTCs. Moreover, the commercial production of pure PHB is not without environmental impacts. To address these issues, we integrated unpurified ...