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Journal of Bacteriology May 1968Poly-beta-hydroxybutyrate (PHB) from various representative strains of the genera Azotobacter, Beijerinckia, and Derxia was isolated and characterized. During growth in...
Poly-beta-hydroxybutyrate (PHB) from various representative strains of the genera Azotobacter, Beijerinckia, and Derxia was isolated and characterized. During growth in shake culture, with glucose as a carbon and energy source, and molecular nitrogen as a nitrogen source, increase in dry weight appeared linear, and PHB formed a constant percentage of the dry weight. In a medium containing 1% (w/v) glucose, PHB declined with the onset of the stationary phase of growth; with 2% (w/v) glucose, an increase in PHB content during stationary phase was noted in the case of some strains, before a subsequent decline. The decrease in PHB as a percentage of dry cellular weight (not of total amount present in the culture) during growth of some strains with 2% as opposed to 1% (w/v) glucose may be ascribed to a greater production of capsular polysaccharide. PHB content could not be used as a taxonomic criterion. Strain differences were as great as or greater than species differences. The only strain of Beijerinckia fluminensis obtained contained PHB, but it could not be grown on the nitrogen-free medium used. Two species of the genus Azotomonas, reported to be aerobic, nonsymbiotic nitrogen-fixers, did not grow on the nitrogen-free medium used and did not produce PHB during growth with a combined nitrogen source.
Topics: Azotobacter; Bacteria; Culture Media; Hydroxybutyrates
PubMed: 5650085
DOI: 10.1128/jb.95.5.1798-1803.1968 -
PloS One 2018The influence of nanomaterials on the ecological environment is becoming an increasingly hot research field, and many researchers are exploring the mechanisms of...
The influence of nanomaterials on the ecological environment is becoming an increasingly hot research field, and many researchers are exploring the mechanisms of nanomaterial toxicity on microorganisms. Herein, we studied the effect of two different sizes of nanosilver (10 nm and 50 nm) on the soil nitrogen fixation by the model bacteria Azotobacter vinelandii. Smaller size AgNPs correlated with higher toxicity, which was evident from reduced cell numbers. Flow cytometry analysis further confirmed this finding, which was carried out with the same concentration of 10 mg/L for 12 h, the apoptotic rates were20.23% and 3.14% for 10 nm and 50 nm AgNPs, respectively. Structural damage to cells were obvious under scanning electron microscopy. Nitrogenase activity and gene expression assays revealed that AgNPs could inhibit the nitrogen fixation of A. vinelandii. The presence of AgNPs caused intracellular reactive oxygen species (ROS) production and electron spin resonance further demonstrated that AgNPs generated hydroxyl radicals, and that AgNPs could cause oxidative damage to bacteria. A combination of Ag content distribution assays and transmission electron microscopy indicated that AgNPs were internalized in A. vinelandii cells. Overall, this study suggested that the toxicity of AgNPs was size and concentration dependent, and the mechanism of antibacterial effects was determined to involve damage to cell membranes and production of reactive oxygen species leading to enzyme inactivation, gene down-regulation and death by apoptosis.
Topics: Apoptosis; Azotobacter vinelandii; Bacterial Proteins; Environmental Pollutants; Gene Expression; Hydroxyl Radical; Metal Nanoparticles; Nitrogen Fixation; Oxidative Stress; Particle Size; Reactive Oxygen Species; Silver Compounds
PubMed: 30566461
DOI: 10.1371/journal.pone.0209020 -
Polish Journal of Microbiology 2013Effects of pre-sowing soybean seed inoculation with Bradyrhizobium japonicum alone or with mixed inoculants containing soybean rhizobia and Azotobacter chroococcum were...
Effects of pre-sowing soybean seed inoculation with Bradyrhizobium japonicum alone or with mixed inoculants containing soybean rhizobia and Azotobacter chroococcum were compared. In the pot experiment all the tested strains of soybean rhizobia in pure cultures or in mixtures with A. chroococcum significantly improved nodulation of soybean plants and seed yields of this crop. In micro-plot experiments pre-sowing soybean seeds treatment with the inoculant containing the most effective strain 94P of B. japonicum alone or with the mixed inoculant of strain 94P and A. chroococcum were equally effective in improving nodulation intensity and seed yields of soybean in comparison to the uninoculated soybean.
Topics: Azotobacter; Bradyrhizobium; Plant Root Nodulation; Seeds; Soil Microbiology; Glycine max
PubMed: 24730143
DOI: No ID Found -
Journal of Bacteriology Jan 1986Azotobacter vinelandii mutants defective for acetate utilization that were resistant to fluoroacetate (FA) were isolated. FA-resistant mutant AM6 failed to transport...
Azotobacter vinelandii mutants defective for acetate utilization that were resistant to fluoroacetate (FA) were isolated. FA-resistant mutant AM6 failed to transport [14C]acetate and lacked enzymatic activity for both acetate kinase and phosphotransacetylase. Growth of wild-type A. vinelandii was sensitive to 10 mM glycine; however, all FA-resistant strains were resistant to glycine toxicity. Isolated mutants that were spontaneously resistant to glycine were also resistant to FA and lacked both acetate kinase and phosphotransacetylase activity. The glycine-resistant mutant AM3, unlike mutant AM6, was capable of growth on acetate. The mutant strain AM6 was unable to growth under acetate-glucose diauxie conditions. Glucose utilization in this mutant, unlike that in wild-type A. vinelandii, was permanently arrested in the presence of acetate. Revertants of strain AM6 were selected on plates with acetate or acetate-glucose. Two classes of revertants were isolated. Class I revertant mutants AM31 and AM35 were positive for both acetate kinase and phosphotransacetylase activities. These revertants were also sensitive to both FA and glycine. Class II revertant strains AM32 and AM34 still lacked acetate kinase and phophotransacetylase activity. Both of these revertants remained resistant to FA and glycine.
Topics: Acetate Kinase; Acetates; Acetic Acid; Acetyltransferases; Azotobacter; Fluoroacetates; Glucose; Mutation; Oxygen Consumption; Phosphate Acetyltransferase; Phosphotransferases
PubMed: 3001033
DOI: 10.1128/jb.165.1.6-12.1986 -
European Journal of Biochemistry Jun 1980
Topics: Azotobacter; Enzymes, Immobilized; Macromolecular Substances; NADH, NADPH Oxidoreductases; NADP Transhydrogenases; Polymers
PubMed: 7398644
DOI: No ID Found -
Journal of Bacteriology Nov 1970Vegetative cells and cysts of Azotobacter vinelandii 12837 were prepared for electron microscopy by several methods assumed to preserve structural details destroyed by...
Vegetative cells and cysts of Azotobacter vinelandii 12837 were prepared for electron microscopy by several methods assumed to preserve structural details destroyed by techniques previously reported in the literature. Examination of large numbers of cells and cysts by these methods revealed four structural details not reported previously: intine fibrils, intine vesicles, intine membrane, and microtubules. The intine fibrils form a network in the gel-like homogeneous matrix of the CC2 layer. Intine vesicles which seem to originate in the cell wall complex of the central body are seen in the intine and exine of cysts. Analogous structures are found on vegetative cells. The intine is divided into two chemically distinct areas by the two-layered intine membrane. Microtubules, previously reported only in vegetative cells, were found in cysts.
Topics: Acetates; Aldehydes; Arsenic; Azotobacter; Bacteriological Techniques; Cell Membrane; Cell Wall; Chromates; Cytoplasm; Freeze Drying; Lead; Microscopy, Electron; Microtubules; Osmium; Oxides; Potassium; Staining and Labeling; Tartrates; Uranium
PubMed: 4099100
DOI: 10.1128/jb.104.2.933-939.1970 -
Journal of Bacteriology Aug 1978Dormant cysts of Azotobacter vinelandii germinated at 30 degrees C in Burk nitrogen-free media containing 1% glucose. Samples taken at intervals and examined by electron...
Dormant cysts of Azotobacter vinelandii germinated at 30 degrees C in Burk nitrogen-free media containing 1% glucose. Samples taken at intervals and examined by electron microscopy revealed that as germination progressed, vesicle-like and fibrillar structures became visible in the intine region. Lamellae associated with the cell membrane appeared in the central body at 6 h post-initiation of germination. Both electron micrographic and chemical analysis showed that the poly-beta-hydroxybutyrate content of cysts decreased significantly after 4 h of germination. Dormant cysts were resistant to sonic oscillation, but this property was lost during their conversion to metabolically active vegetative cells.
Topics: Azotobacter; Cell Membrane; Cytoplasmic Granules; Hydroxybutyrates; Vacuoles
PubMed: 681284
DOI: 10.1128/jb.135.2.641-646.1978 -
The Journal of Biological Chemistry Jul 1988The crystal structure of the 7Fe ferredoxin from Azotobacter vinelandii has been redetermined using area detector data to 2.7-A resolution and a new derivative....
The crystal structure of the 7Fe ferredoxin from Azotobacter vinelandii has been redetermined using area detector data to 2.7-A resolution and a new derivative. Tetragonal crystals of the protein were maintained at pH 8.0. The results show that the structure previously reported was in error and confirms a recent independent report of the structure (Stout, G.H., Turley, S., Sieker, L. C., and Jensen, L. H. (1988) Proc. Natl. Acad. Sci. U. S. A. 85, in press). The protein fold is similar to the homologous 8Fe ferredoxin structure for the N-terminal half of the protein; the C-terminal residues wrap around this structure. The structure contains a 3Fe cluster coordinated by cysteines 8, 16, and 49 and a 4Fe cluster coordinated by cysteines 20, 39, 42, and 45. However, there are two free sulfhydryls, cysteines 11 and 24, in the new model. Cysteine 24 is in contact with the [4Fe-4S] cluster. Cysteine 11 is shielded from solvent by residues 86-90.
Topics: Azotobacter; Ferredoxins; Iron; Models, Molecular; Protein Conformation; X-Ray Diffraction
PubMed: 3379067
DOI: 10.2210/pdb3fd1/pdb -
Journal of Bacteriology May 1953
Topics: Azotobacter; Enzymes; Hydrogenase; Nitrogenase
PubMed: 13069414
DOI: 10.1128/jb.65.5.511-517.1953 -
PloS One 2017This study was conducted to explore the changes in soil microbial populations, enzyme activity, and tuber yield under the rotation sequences of Potato-Common vetch...
This study was conducted to explore the changes in soil microbial populations, enzyme activity, and tuber yield under the rotation sequences of Potato-Common vetch (P-C), Potato-Black medic (P-B) and Potato-Longdong alfalfa (P-L) in a semi-arid area of China. The study also determined the effects of continuous potato cropping (without legumes) on the above mentioned soil properties and yield. The number of bacteria increased significantly (p < 0.05) under P-B rotation by 78%, 85% and 83% in the 2, 4 and 7-year continuous cropping soils, respectively compared to P-C rotation. The highest fungi/bacteria ratio was found in P-C (0.218), followed by P-L (0.184) and then P-B (0.137) rotation over the different cropping years. In the continuous potato cropping soils, the greatest fungi/bacteria ratio was recorded in the 4-year (0.4067) and 7-year (0.4238) cropping soils and these were significantly higher than 1-year (0.3041), 2-year (0.2545) and 3-year (0.3030) cropping soils. Generally, actinomycetes numbers followed the trend P-L>P-C>P-B. The P-L rotation increased aerobic azotobacters in 2-year (by 26% and 18%) and 4-year (40% and 21%) continuous cropping soils compared to P-C and P-B rotation, respectively. Generally, the highest urease and alkaline phosphate activity, respectively, were observed in P-C (55.77 mg g-1) and (27.71 mg g-1), followed by P-B (50.72 mg mg-1) and (25.64 mg g-1) and then P-L (41.61 mg g-1) and (23.26 mg g-1) rotation. Soil urease, alkaline phosphatase and hydrogen peroxidase activities decreased with increasing years of continuous potato cropping. On average, the P-B rotation significantly increased (p <0.05) tuber yield by 19% and 18%, compared to P-C and P-L rotation respectively. P-L rotation also increased potato tuber yield compared to P-C, but the effect was lesser relative to P-B rotation. These results suggest that adopting potato-legume rotation system has the potential to improve soil biology environment, alleviate continuous cropping obstacle and increase potato tuber yield in semi-arid region.
Topics: Actinobacteria; Alkaline Phosphatase; Azotobacter; Crop Production; Fabaceae; Medicago sativa; Plant Tubers; Soil; Soil Microbiology; Solanum tuberosum; Urease; Vicia sativa
PubMed: 28463981
DOI: 10.1371/journal.pone.0175934