Biochemical and molecular characterization of an Azotobacter vinelandii strain with respect to its ability to grow and fix nitrogen in olive mill wastewater (original) (raw)
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Selective inactivation of the nitrogenase in Azotobacter vinelandii batch cultures
Journal of Bacteriology
D Kleiner and J A Kleinschmidt vinelandii batch cultures. nitrogenase in Azotobacter Selective inactivation of http://jb.asm.org/content/128/1/117 found at: Updated information and services can be These include: CONTENT ALERTS more» alerts (when new articles cite this article), Receive: RSS Feeds, eTOCs, free email http://journals.asm.org/site/misc/reprints.xhtml Information about commercial reprint orders: http://journals.asm.org/site/subscriptions/ To subscribe to to another ASM Journal go to: on October 5, 2012 by guest
D Kleiner and J A Kleinschmidt vinelandii batch cultures. nitrogenase in Azotobacter Selective inactivation of http://jb.asm.org/content/128/1/117 found at: Updated information and services can be These include: CONTENT ALERTS more» alerts (when new articles cite this article), Receive: RSS Feeds, eTOCs, free email http://journals.asm.org/site/misc/reprints.xhtml Information about commercial reprint orders: http://journals.asm.org/site/subscriptions/ To subscribe to to another ASM Journal go to: on October 5, 2012 by guest
Canadian Journal of Microbiology, 1983
Mutant strains of Azotobacter vinelandii which might have potential for use as bacterial fertilizer have been isolated and fall into two categories: constitutive mutants that synthesize nitrogenase in the presence of ammonium and mutants that overproduce nitrogenase when grown in nitrogen-free medium. The constitutive mutants described in this paper were isolated from the wild type as methylalanine-resistant strains and express up to 23% of the fully derepressed nitrogenase level when grown in medium containing excess ammonium. By contrast, ammonium-grown cultures of wild type have less than 0.003% of the fully derepressed level. Strains which fix more N2 than the wild type in nitrogen-free medium were isolated as mefhylammonium-resistant mutants. Although the methylammonium-resistant mutant strains fix more N2 than the wild type, they grow no faster. The excess nitrogen produced by these mutants is excreted into the medium, resulting in up to 60% more nitrogen than in the medium of...
Genes required for rapid expression of nitrogenase activity in Azotobacter vinelandii
Proceedings of the National Academy of Sciences, 2005
Rnf proteins are proposed to form membrane-protein complexes involved in the reduction of target proteins such as the transcriptional regulator SoxR or the dinitrogenase reductase component of nitrogenase. In this work, we investigate the role of rnf genes in the nitrogen-fixing bacterium Azotobacter vinelandii . We show that A. vinelandii has two clusters of rnf -like genes: rnf1 , whose expression is nif -regulated, and rnf2 , which is expressed independently of the nitrogen source in the medium. Deletion of each of these gene clusters produces a time delay in nitrogen-fixing capacity and, consequently, in diazotrophic growth. Δ rnf mutations cause two distinguishable effects on the nitrogenase system: ( i ), slower nifHDK gene expression and ( ii ), impairment of nitrogenase function. In these mutants, dinitrogenase reductase activity is lowered, whereas dinitrogenase activity remains essentially unaltered. Further analysis indicates that Δ rnf mutants accumulate an inactive and ...
Evidence for an alternative nitrogen fixation system in Azotobacter vinelandii
Proceedings of the National Academy of Sciences, 1980
Two Azotobacter vinelandii strains capable of growing on N2(Nif+) were isolated from two different mutant strains that lacked dinitrogenase activity (Nif-). Extracts of N2-grown cells of the two Nif+ strains lacked significant amounts of the "conventional" dinitrogenase protein subunits, as determined by two-dimensional gel electrophoresis. Instead, the extracts contained at least four new proteins that appeared to be ammonia-repressible (i.e., they were not detected in extracts of ammonia-grown cells). Based on the results of genetic backcrosses, the two Nif+ strains were shown to be pseudorevertants. Both Nif+ pseudorevertant strains were able to grow in N-free media lacking molybdenum but containing tungsten (conditions that prevented growth of the wild-type strain). The four new proteins were observed in extracts of N2-fixing cells of the Nif+ pseudorevertants regardless of whether the cells were grown in the presence of molybdenum-starved wild-type A. vinelandii cells...
Archives of Microbiology, 1974
A method is described which allows the quantitative determination of small ammonia concentrations in the culture of nitrogen-fixing microorganisms. With this method the ammonia concentration range was estimated in which repression of nitrogenasc synthesis in Azotobacter vinelandii occurs. Both in batch and continuous cultures there was no repression below 10 ~M, whereas nitrogenase synthesis stopped completely if the ammonia concentration in the medium exceeded 25 ~M.
Growth and nitrogenase activity of Azotobacter vinelandii on soil phenolic acids
Journal of Applied Bacteriology, 1990
... Accepted 14 May 1990 MORENO, J., DE LA RuBIA,T., RAMOS-CORMENZANA, A. & VELA, GR 1990. ... Journal of General Microbiology 9,89-96. HAIDER, K., MARTIN, JP & FILIP, Z. 1975 Humus Biochemistry. In Soil Biochemistry, Vol. 4 ed. Paul, EA & McLaren, AD pp. 195-244. ...
Nitrogenase activity of immobilizedAzotobacter vinelandii
Biotechnology and Bioengineering, 1979
As part of a program to investigate the use of biological nitrogen fixation for fertilizer ammonia production, an investigation into the immobilization of the aerobic, nitrogen-fixing bacterium, Azotohucter vinelmdii was undertaken. Immobilization was accomplished by adsorption onto an anionic exchange cellulose (Cellex E ) with loadings as high as 10" cellsig resin. Immobilized cell preparations were tested under both batch and continuous-flow conditions. Nitrogenase activities as high as 4200 nmollmin g resin were observed as measured by the acetylene reduction assay. Immobilized cells retained their activity for as long as 117 hr in a continuous-flow reactor. Activity loss appeared to be related to the development of a variant strain.