Ammonium inhibition of nitrogenase activity in Herbaspirillum seropedicae.
Haian Fu,R. H. Burris +1 more
TLDR
The effect of oxygen, ammonium ion, and amino acids on nitrogenase activity in the root-associated N2-fixing bacterium Herbaspirillum seropedicae was investigated and there is no clear evidence that ADP-ribosylation of the dinitrogenase reductase is involved in the ammonium inhibition of H. seropedICae.Abstract:
The effect of oxygen, ammonium ion, and amino acids on nitrogenase activity in the root-associated N2-fixing bacterium Herbaspirillum seropedicae was investigated in comparison with Azospirillum spp. and Rhodospirillum rubrum. H. seropedicae is microaerophilic, and its optimal dissolved oxygen level is from 0.04 to 0.2 kPa for dinitrogen fixation but higher when it is supplied with fixed nitrogen. No nitrogenase activity was detected when the dissolved O2 level corresponded to 4.0 kPa. Ammonium, a product of the nitrogenase reaction, reversibly inhibited nitrogenase activity when added to derepressed cell cultures. However, the inhibition of nitrogenase activity was only partial even with concentrations of ammonium chloride as high as 20 mM. Amides such as glutamine and asparagine partially inhibited nitrogenase activity, but glutamate did not. Nitrogenase in crude extracts prepared from ammonium-inhibited cells showed activity as high as in extracts from N2-fixing cells. The pattern of the dinitrogenase and the dinitrogenase reductase revealed by the immunoblotting technique did not change upon ammonium chloride treatment of cells in vivo. No homologous sequences were detected with the draT-draG probe from Azospirillum lipoferum. There is no clear evidence that ADP-ribosylation of the dinitrogenase reductase is involved in the ammonium inhibition of H. seropedicae. The uncoupler carbonyl cyanide m-chlorophenylhydrazone decreased the intracellular ATP concentration and inhibited the nitrogenase activity of whole cells. The ATP pool was not significantly disturbed when cultures were treated with ammonium in vivo. Possible mechanisms for inhibition by ammonium of whole-cell nitrogenase activity in H. seropedicae are discussed.read more
Citations
More filters
Journal ArticleDOI
Azospirillum, a free-living nitrogen-fixing bacterium closely associated with grasses: genetic, biochemical and ecological aspects
Oda Steenhoudt,Jos Vanderleyden +1 more
TL;DR: Four aspects of the Azospirillum-plant root interaction are highlighted: natural habitat, plant root interaction, nitrogen fixation and biosynthesis of plant growth hormones, and the relevance of each of these four aspects for plant growth promotion by AzospIRillum is discussed.
Journal ArticleDOI
Infection and Colonization of Sugar Cane and Other Graminaceous Plants by Endophytic Diazotrophs
TL;DR: Agriculturally important grasses such as sugar cane (Saccharum sp.), rice (Oryza sativa), wheat (Triticum aestivum) sorghum (Sorghum bicolor), maize (Zea mays), Panicum maximum, Brachiaria spp.
Book ChapterDOI
Biological nitrogen fixation associated with sugar cane
TL;DR: A recent15N dilution/N balance study confirmed that certain sugar cane varieties are capable of obtaining large contributions of nitrogen from plant-associated N2 fixation, and under good conditions of water and mineral nutrient supply, it may be possible to dispense with N fertilization of these varieties altogether.
Journal ArticleDOI
Enzymatic mechanism and biochemistry for cyanide degradation: a review.
TL;DR: Different enzymes, their mechanisms and corresponding pathways with respect to the known biochemistry of enzyme and feasibility for the use in treatment of cyanides containing industrial effluents are dealt with.
Journal ArticleDOI
PII signal transduction proteins: nitrogen regulation and beyond
TL;DR: This review sets out to summarize the current understanding of P(II) biology and to consider where future studies of these extraordinarily adaptable proteins might lead us.
References
More filters
Journal ArticleDOI
Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4
TL;DR: Using an improved method of gel electrophoresis, many hitherto unknown proteins have been found in bacteriophage T4 and some of these have been identified with specific gene products.
Book
Molecular Cloning: A Laboratory Manual
TL;DR: Molecular Cloning has served as the foundation of technical expertise in labs worldwide for 30 years as mentioned in this paper and has been so popular, or so influential, that no other manual has been more widely used and influential.
Journal Article
Cleavage of structural proteins during the assemble of the head of bacterio-phage T4
TL;DR: Using an improved method of gel electrophoresis, many hitherto unknown proteins have been found in bacteriophage T4 and some of these have been identified with specific gene products as mentioned in this paper.
Journal ArticleDOI
A technique for radiolabeling DNA restriction endonuclease fragments to high specific activity
TL;DR: A technique for conveniently radiolabeling DNA restriction endonuclease fragments to high specific activity is described, and these "oligolabeled" DNA fragments serve as efficient probes in filter hybridization experiments.
A technique for radiolabeling DNA restriction endonuclease fragments to high specific activity
TL;DR: In this article, a technique for conveniently radiolabeling DNA restriction endonuclease fragments to high specific activity is described, where DNA fragments are purified from agarose gels directly by ethanol precipitation and are then denatured and labeled with the large fragment of DNA polymerase I, using random oligonucleotides as primers.