Acetylene Reduction Analysis
Mostrando 13-21 de 21 artigos, teses e dissertações.
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13. Endophytic Colonization of Rice by a Diazotrophic Strain of Serratia marcescens
Six closely related N2-fixing bacterial strains were isolated from surface-sterilized roots and stems of four different rice varieties. The strains were identified as Serratia marcescens by 16S rRNA gene analysis. One strain, IRBG500, chosen for further analysis showed acetylene reduction activity (ARA) only when inoculated into media containing low levels o
American Society for Microbiology.
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14. Effect of Nitrate on the Organic Acid and Amino Acid Composition of Legume Nodules 1
Nitrate supplied to legume plants inhibits the activity of nitrogenase in Rhizobium bacteroids in root nodules. The accumulation of amino N which is known to occur in Glycine max (L.) Merr. nodules as nitrogenase activity declines was studied in more detail by analysis of changes in free amino acid composition in response to high nitrate supply. A 6-fold inc
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15. Molybdenum independence of nitrogenase component synthesis in the non-heterocystous cyanobacterium Plectonema.
The cyanobacterium Plectonema boryanum (IU 594-UTEX 594) fixes N2 only in the absence of combined N and of O2. We induced nitrogenase by transfer to anaerobic N-free medium and studied the effect of Mo starvation on nitrogenase activity and synthesis. Activity was first detected within 3 h after transfer by the acetylene reduction assay in controls, increasi
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16. A mutant of Azospirillum brasilense Sp7 impaired in flocculation with a modified colonization pattern and superior nitrogen fixation in association with wheat.
We report here significant phenotypic and genetic differences between Azospirillum brasilense Sp7 and spontaneous mutant Sp7-S and their related properties in association with wheat. In contrast to the wild-type strain of Sp7, colonies of Sp7-S stained weakly with Congo red when grown on agar media containing the dye and did not flocculate in the presence of
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17. Coliform Bacteria and Nitrogen Fixation in Pulp and Paper Mill Effluent Treatment Systems
The majority of pulp and paper mills now biotreat their combined effluents using activated sludge. On the assumption that their wood-based effluents have negligible fixed N, and that activated-sludge microorganisms will not fix significant N, these mills routinely spend large amounts adding ammonia or urea to their aeration tanks (bioreactors) to permit norm
American Society for Microbiology.
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18. nifH Sequences and Nitrogen Fixation in Type I and Type II Methanotrophs
Some methane-oxidizing bacteria (methanotrophs) are known to be capable of expressing nitrogenase and utilizing N2 as a nitrogen source. However, no sequences are available for nif genes in these strains, and the known nitrogen-fixing methanotrophs are confined mainly to a few genera. The purpose of this work was to assess the nitrogen-fixing capabilities of
American Society for Microbiology.
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19. Transcriptional and Mutational Analysis of the Uptake Hydrogenase of the Filamentous Cyanobacterium Anabaena variabilis ATCC 29413
A 10-kb DNA region of the cyanobacterium Anabaena variabilis ATCC 29413 containing the structural genes of the uptake hydrogenase (hupSL) was cloned and sequenced. In contrast to the hupL gene of Anabaena sp. strain PCC 7120, which is interrupted by a 10.5-kb DNA fragment in vegetative cells, there is no programmed rearrangement within the hupL gene during t
American Society for Microbiology.
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20. The arginine deiminase pathway in Rhizobium etli: DNA sequence analysis and functional study of the arcABC genes.
Sequence analysis upstream of the Rhizobium etli fixLJ homologous genes revealed the presence of three open reading frames homologous to the arcABC genes of Pseudomonas aeruginosa. The P. aeruginosa arcABC genes code for the enzymes of the arginine deiminase pathway: arginine deiminase, catabolic ornithine carbamoyltransferase (cOTCase), and carbamate kinase
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21. Nucleotide sequence and genetic analysis of the nifB-nifQ region from Azotobacter vinelandii.
A 3.8-kilobase-pair EcoRI fragment which corrects the mutations carried by the NifB- Azotobacter vinelandii strains CA30 and UW45 was cloned, and its nucleotide sequence was determined. Four complete open reading frames (ORFs) and two partial ORFs were found. The translation product of the first partial ORF is the carboxy-terminal end of a protein homologous