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Journal of Bacteriology Dec 1967
Topics: Azotobacter; Cytoplasm; Microscopy, Electron
PubMed: 6074408
DOI: 10.1128/jb.94.6.2062-2064.1967 -
Journal of Basic Microbiology Jun 2010Ten strains of Azotobacter chroococcum were studied for their ability to invade the endorhizosphere of wheat. Strain W-5 exhibited ability to invade endorhizosphere as... (Comparative Study)
Comparative Study
Ten strains of Azotobacter chroococcum were studied for their ability to invade the endorhizosphere of wheat. Strain W-5 exhibited ability to invade endorhizosphere as shown in the microscopic observations. This strain was compared with the strain OA-3 which did not invade the endorhizosphere zone. Strain W-5 showed higher production of cellulase and pectinase than OA-3. Both the strains induced defense enzymes in the host plant. However, induction of peroxidase and phenylalanine ammonia lyase activities (PAL) was higher in OA-3 than W-5. Quantitative differences in flavonoid like compounds obtained from root extracts and root exudates of plants inoculated with these strains were observed.
Topics: Azotobacter; Bacterial Proteins; Cell Extracts; Cellulase; Flavonoids; Peroxidase; Phenylalanine Ammonia-Lyase; Plant Proteins; Plant Roots; Polygalacturonase; Triticum
PubMed: 20473953
DOI: 10.1002/jobm.200900218 -
Journal of Bacteriology Oct 1969When young cells of Azotobacter vinelandii are impinged on membrane filters, washed free of carbon substrate, and placed on a mineral salts basal medium, the culture...
When young cells of Azotobacter vinelandii are impinged on membrane filters, washed free of carbon substrate, and placed on a mineral salts basal medium, the culture will proceed to encyst although at a slower rate than if n-butanol were supplied as a substrate. The endogenous cysts are depleted in polybeta-hydroxybutyrate and have a narrower intine but show an increased resistance to desiccation and are susceptible to lysis by chelating agents. Membrane-supported cells reveal details of the encystment process such as the formation of a zone within the capsule prior to exine formation and the early deposition of exine structures.
Topics: Azotobacter; Bacteriolysis; Culture Media; Filtration; Freeze Drying; Membranes, Artificial; Microscopy, Electron
PubMed: 5344107
DOI: 10.1128/jb.100.1.475-479.1969 -
Nature Apr 1963
Topics: Acids; Azotobacter; Azotobacter vinelandii; Uronic Acids
PubMed: 14022036
DOI: 10.1038/198211a0 -
Journal of General Microbiology Jun 1969
Topics: Adenosine Triphosphate; Ammonium Chloride; Azotobacter; Culture Media; Cytochromes; Nitrogen Fixation; Oxidoreductases; Oxygen Consumption; Phosphates
PubMed: 5797517
DOI: 10.1099/00221287-56-3-307 -
Cytometry 1990When Azotobacter vinelandii is grown under nitrogen-fixing conditions, the mean cell volume fluctuates from 2.7 to 6.6 microns 3 as determined using a Coulter counter....
When Azotobacter vinelandii is grown under nitrogen-fixing conditions, the mean cell volume fluctuates from 2.7 to 6.6 microns 3 as determined using a Coulter counter. When NH4Cl is supplied as nitrogen source, the mean cell volume fluctuates from 4.6 to 7.4 microns3. Parallel experiments using flow cytometric measurements show similar characteristic fluctuations in the narrow forward angle light scattering signal and also in cellular protein content as determined using fluorescein isothiocyanate (FITC) fluorescence. Fluctuations in the perpendicular light scatter signal during batch growth are similar for both sets of growth conditions. Changes in cell morphology and ultrastructure are also similar for both sets of growth conditions, as demonstrated by electron microscopic examination. We conclude that narrow forward angle light scatter is a close correlate of cell size, whereas right angle scatter is an indicator of morphological variations other than size.
Topics: Ammonium Chloride; Animals; Azotobacter; Cell Division; Flow Cytometry; Fluorescein-5-isothiocyanate; Fluoresceins; Light; Microscopy, Electron; Microscopy, Electron, Scanning; Microscopy, Fluorescence; Proteins; Scattering, Radiation; Thiocyanates
PubMed: 2125552
DOI: 10.1002/cyto.990110708 -
Bacteriological Reviews Dec 1975
Topics: Azotobacter; Bacterial Proteins; Chromosomes, Bacterial; DNA; Morphogenesis; RNA; Spores, Bacterial; Transformation, Genetic
PubMed: 1212151
DOI: 10.1128/br.39.4.516-539.1975 -
Journal of General Microbiology Aug 1987Azotobacter vinelandii OP which had been naturally induced to competence by growth in iron- and molybdenum-limited medium was transformed with the broad-host-range...
Azotobacter vinelandii OP which had been naturally induced to competence by growth in iron- and molybdenum-limited medium was transformed with the broad-host-range cloning vector pKT210. However, the transformation frequency at nearly saturating levels of DNA was 1000-fold lower for pKT210 than for a single chromosomal DNA marker (nif+). Plasmid- and chromosomal-DNA-mediated transformation events were competitive, magnesium-dependent, 42 degrees C-sensitive processes specific to double-stranded DNA, suggesting a common mechanism of DNA binding and uptake. The low frequency of plasmid transformation was not related to restriction of transforming DNA or to the growth period allowed for phenotypic expression. Covalently-closed-circular and open-circular forms of pKT210 transformed cells equally well whereas EcoRI- or HindIII-linearized pKT210 transformed cells with two to three times greater efficiency. Genetic transformation was enhanced 10- to 50-fold when pKT210 contained an insert fragment of A. vinelandii nif DNA, indicating that A. vinelandii possessed a homology-facilitated transformation system. However, all transformants failed to maintain the plasmid-encoded antibiotic resistance determinants, and extrachromosomal plasmid DNA was not recovered from these cells. Flush-ended pKT210 was not active in transformation; however, competent cells were transformed to Nif+ by HincII-digested plasmid DNA containing the cloned A. vinelandii nif-10 marker.
Topics: Azotobacter; Chromosomes, Bacterial; DNA, Bacterial; Microscopy, Electron; Plasmids; Transformation, Bacterial
PubMed: 3443852
DOI: 10.1099/00221287-133-8-2059 -
The Journal of Biological Chemistry May 1979Two crystal forms of Azotobacter vinelandii (4Fe-4s)2 ferredoxin I (Fd I) have been grown which are suitable for high resolution x-ray diffraction studies. Tetragonal...
Two crystal forms of Azotobacter vinelandii (4Fe-4s)2 ferredoxin I (Fd I) have been grown which are suitable for high resolution x-ray diffraction studies. Tetragonal crystals grow as square bipyramids from ammonium sulfate and Tris buffer using a temperature gradient. The space group is P41212 (or P43212) with a = 55.3, c = 95.9 A and 1 molecule/asymmetric unit. Triclinic crystals grow as plates or laths from ammonium sulfate and phosphate buffer at constant temperature. The space group is P1 with a = 46.8, b = 58.7, c = 64.3 A, alpha = = 105 degrees 05 min, beta = 82 degrees 30 min, gamma = 110 degrees 30 min and 4 or 5 molecules/unit cell. Both crystal forms are stable to x-ray irradiation and diffract beyond 3.0 A resolution.
Topics: Azotobacter; Crystallization; Ferredoxins; Protein Conformation; X-Ray Diffraction
PubMed: 429371
DOI: No ID Found -
Folia Microbiologica 2001Thirty-seven soil isolates and mutants of Azotobacter chroococcum tested for poly-3-hydroxybutyrate (PHB) production using Sudan black B staining method were found to be...
Thirty-seven soil isolates and mutants of Azotobacter chroococcum tested for poly-3-hydroxybutyrate (PHB) production using Sudan black B staining method were found to be positive. One mutant showed a higher number of PHB-producing cells and maximum number of granules per cell. Using 2% glucose and 15 mmol/L ammonium acetate, PHB production was found to be maximum at 36 and 48 h of growth under submerged cultivation and under stationary cultivation, respectively. PHB production was found to be higher on sucrose and commercial sugar (as carbon sources) as compared to glucose and mannitol. As commercial sugar is cheaper than sucrose it was selected as carbon source for PHB production, that being found to be maximum at 1% concentration. Inorganic nitrogen sources seemed to have no stimulatory effect on the production of PHB. However, ammonium acetate (15 mmol/L) was found to be best for PHB production. Peptone (0.2%) gave a better yield of PHB under both growth conditions. Using all optimized conditions, PHB production was studied in ten selected strains. Two of them were found to be best PHB producers under both growth conditions, one producing 621 and 740 micrograms/g dry mass under submerged cultivation and under stationary cultivation, respectively, while the second one produced 589 and 733 micrograms/g.
Topics: Azo Compounds; Azotobacter; Culture Media; Hydroxybutyrates; Naphthalenes; Polyesters; Soil Microbiology; Staining and Labeling
PubMed: 11830943
DOI: 10.1007/BF02815620