Search results for "Carbon fixation"
showing 7 items of 17 documents
Nitrogen fixation and methanotrophy in forest mosses along a N deposition gradient
2013
Abstract Nitrogen deposition has decreased the plant-associated nitrogen (N 2 ) fixation when measured using the indirect acetylene reduction assay (ARA). However, nitrogen deposition can also lead to changes in the diversity of moss symbionts, e.g. affect methanotrophic N 2 fixation, which is not measured by ARA. To test this hypothesis we compared ARA with the direct stable isotope method ( 15 N 2 incorporation) and studied methanotrophy in two mosses, Hylocomium splendens and Pleurozium schreberi , collected from seven forest sites along a boreal latitudinal N deposition transect. We recognized that the two independent N 2 fixation measures gave corresponding results with the conversion …
In Situ X-Ray Tomography Imaging of Soil Water and Cyanobacteria From Biological Soil Crusts Undergoing Desiccation
2018
Biological soil crusts (biocrusts) are millimeter-sized microbial communities developing on the topsoils of arid lands that cover some 12% of Earth’s continental area. Biocrusts consist of an assemblage of mineral soil particles consolidated into a crust by microbial organic polymeric substances that are mainly produced by the filamentous bundle-forming cyanobacteria, among which Microcoleus vaginatus is perhaps the most widespread. This cyanobacterium is the primary producer for, and main architect of biocrusts in many arid soils, sustaining the development of a diverse microbial community. Biocrusts are only active when wet, and spend most of their time in a state of desiccated quiescence…
Variety of size and form of GRM2 bacterial microcompartment particles
2021
Bacterial microcompartments (BMCs) are bacterial organelles involved in enzymatic processes, such as carbon fixation, choline, ethanolamine and propanediol degradation, and others. Formed of a semi‐permeable protein shell and an enzymatic core, they can enhance enzyme performance and protect the cell from harmful intermediates. With the ability to encapsulate non‐native enzymes, BMCs show high potential for applied use. For this goal, a detailed look into shell form variability is significant to predict shell adaptability. Here we present four novel 3D cryo‐EM maps of recombinant Klebsiella pneumoniae GRM2 BMC shell particles with the resolution in range of 9 to 22 Å and nine novel 2D class…
Changes in net photosynthesis, chlorophyll fluorescence and xanthophyll cycle interconversions during freeze-thaw cycles in the Mediterranean moss Le…
1999
The tolerance to freezing and thawing of Leucodon sciuroides, a moss growing in mountainous areas of the Mediterranean (south-east Spain), was investigated by means of CO2 gas exchange, modulated chlorophyll (Chl) a fluorescence and pigment analysis by high-performance liquid chromatography. Evidence is presented for freezing-induced decreases in CO2 fixation that enhance non-radiative dissipation of absorbed light energy, a process which protects the photosynthetic apparatus. The photosynthetic apparatus of L. sciuroides remained fully recuperable after freezing, as indicated by the recovery of photosynthetic CO2 fixation and Chl fluorescence parameters to pre-freezing values during thawin…
The Influence of Brassinosteroid, a Growth-promoting Steroidal Lactone, on Development and CO2-fixation Capacity of Intact Wheat and Mustard Seedlings
1984
In 1970, Mitchell et al. isolated a lipoidal complex from the pollen of rape (Brassica napus L.). This complex, called “Brassins” was found to have partly powerful growth-promoting properties. The novel growth response of young bean plants in the second internode assay (Worley, Mitchell 1971; Mitchell, Gregory 1972) and other physiological changes following Brassin-treatment have been studied under several aspects (Krizek, Worley 1981; Gregory 1981).
Reversible inhibition of CO2fixation by ribulose 1,5-bisphosphate carboxylase/oxygenase through the synergic effect of arsenite and a monothiol
2013
The activity of the photosynthetic carbon-fixing enzyme, ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), is partially inhibited by arsenite in the millimolar concentration range. However, micromolar arsenite can fully inhibit Rubisco in the presence of a potentiating monothiol such as cysteine, cysteamine, 2-mercaptoethanol or N-acetylcysteine, but not glutathione. Arsenite reacts specifically with the vicinal Cys172-Cys192 from the large subunit of Rubisco and with the monothiol to establish a ternary complex, which is suggested to be a trithioarsenical. The stability of the complex is strongly dependent on the nature of the monothiol. Enzyme activity is fully recovered through …
CO2 Fixation by Copper(II) Complexes of a Terpyridinophane Aza Receptor
2004
CO2 is fixed by a Cu2+ complex of a macrocyclic terpyridinophane ligand forming a carbamate group. Several features of the structure mimic the enzyme rubisco.