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The Chemistry of O-Polysaccharide Chains in Bacterial Lipopolysaccharides
Published in Helmut Brade, Steven M. Opal, Stefanie N. Vogel, David C. Morrison, Endotoxin in Health and Disease, 2020
Rhizobial bacteria have the unique property of nitrogen fixation, through a complex multistep interaction. The O-specificity is changed when they convert to nitrogen-fixing bacteria, and the LPS has therefore attracted attention. The R. leguminosarium bv. trifolii strain 24 LPS (106) contains a sugar previously only found in plants, 3-deoxy-lyxo-heptulosaric acid (absolute configuration not determined) and in addition 6-deoxy-l-talose. In R. loti the O-polysaccharide was found in the phenol phase after phenol-water extraction, due to the hydrophobicity of the chain (Table 9). The enrichment of O-antigen in the phenol phase was also observed for R. tropici strain CIAT899 (107). Other phenol-soluble S-type LPS has been observed from Pseudomonas aeruginosa 07 (108), Legionella pneumophila O1 (105), and Citrobacter freundii (109).
The Genetics of the Frankia-Actinorhizal Symbiosis
Published in Peter M. Gresshoff, Molecular Biology of Symbiotic Nitrogen Fixation, 2018
Pascal Simonet, Philippe Normand, Ann M. Hirsch, Antoon D. L. Akkermans
The process of biological nitrogen fixation which is carried out by a number of prokaryotic organisms via the nitrogenase enzyme complex remains rate-limiting in many agricultural areas. There has been much discussion about improving biological nitrogen fixation, especially the Rhizobium-legume symbiosis which is the best known. However, many other symbiotic associations occur, and these have been recently reviewed.1,2 Symbiosis between woody, dicotyledonous plants and Frankia, a filamentous prokaryote which is classified in the order Actinomycetales,3 is particularly interesting, and several reviews have been published recently that describe in detail various aspects of the Frankia-actinorhizal plant symbiosis. These include the biology of Frankia,4 the efficiency of the nitrogen-fixing activity of the actinorhizal association,5 the ecology,6 host plant-endophyte specificity, and the genetics of Frankia.7 The progress in Frankia-actinorhizal plant symbiosis has been presented in the proceedings of symposia on this subject during the last decade: Petersham,8 Corvallis,9 Madison,10 Wageningen,11 Laval,12 and Umeå.13
Biology of microbes
Published in Philip A. Geis, Cosmetic Microbiology, 2006
The latter two are sometimes contaminants of personal care products, so we will touch briefly on nitrogen fixation. Realize, however, that nitrogen fixation is primarily a function of organisms that are not of concern to the cosmetic or drug microbiologist. Nitrogen fixation is the reduction of atmospheric gaseous nitrogen into ammonia by nitrogenase. It requires at least 6 electrons for reducing power and 12 ATP molecules.
Insights in nodule-inhabiting plant growth promoting bacteria and their ability to stimulate Vicia faba growth
Published in Egyptian Journal of Basic and Applied Sciences, 2022
Amr M. Mowafy, Mona S. Agha, Samia A. Haroun, Mohamed A. Abbas, Mohamed Elbalkini
Symbiotic nitrogen fixation, which is positioned as a major part of biological nitrogen fixation, is an important alternative source of chemical nitrogen fertilizers not only for leguminous but also for non-leguminous plants. The interaction between legumes and rhizobia leads to root nodule organogenesis, an organ that is produced in response to bacterial nod factors and plant developmental signals leading to the formation of a plant stem cell niche [1]. Recently, rhizobia have been shown to improve the nutrition of non-leguminous crops, such as barley, wheat and canola [2]. It has been established that the legume nodule is exclusively inhabited by the rhizobium. Meanwhile, in 2001, this concept has changed dramatically when non-rhizobial strains were regarded for their ability to nodulate legumes, such as Methylobacterium and Burkholderia that have been isolated from Crotalaria [3] and Mimosa [4], respectively. In addition to nodule-inducing bacteria, several bacterial strains have been isolated from nodules as co-inhabitants with rhizobium, such as Klebsiella, Pseudomonas [5], Bacillus [6] and Streptomyces [7]. Interestingly, a review titled ‘the nodule microbiome: N2-fixing rhizobia do not live alone’ has been published in 2017 to conclude that some of these non-rhizobial bacteria might be nitrogen fixer or participate in nodule genesis and the others, more striking, might neither participate in nodulation nor fix nitrogen [8].
Graphene oxide influence in soil bacteria is dose dependent and changes at osmotic stress: growth variation, oxidative damage, antioxidant response, and plant growth promotion traits of a Rhizobium strain
Published in Nanotoxicology, 2022
Tiago Lopes, Paulo Cardoso, Diana Matos, Ricardo Rocha, Adília Pires, Paula Marques, Etelvina Figueira
Soil microorganisms, although constituting less than 0.5% (w/w) of soil mass, are an essential part of soil ecosystems, for playing important ecological roles that influence soil properties (Yan et al. 2015; Jansson and Hofmockel 2020). Oxidation, nitrification, ammonification, nitrogen fixation, and organic matter mineralization are processes driven by soil microorganisms that make nutrients available for plant uptake (Yan et al. 2015). Some climatic events can interfere with these processes, shifting microbial communities and affecting soil properties and soil nutrient cycles (Jansson and Hofmockel 2020). With the increase of extreme weather events, already taking place in Europe and predicted to increase along the twenty-first century (IPCC 2021), such as the prevalence of long and severe drought events, mainly in spring and summer), effects on microbial communities and the services they provide can be difficult to predict, especially in the Mediterranean region considered as a hotspot (IPCC 2021).
An overview on cyanobacterial blooms and toxins production: their occurrence and influencing factors
Published in Toxin Reviews, 2022
Isaac Yaw Massey, Muwaffak Al osman, Fei Yang
It is well established that nitrogen fixation is an important feature of some cyanobacteria species and in terms of nutrition nitrogen-fixing, cyanobacteria are considered the most self-sufficient among other organisms. They are photoautotrophs that require only light energy, CO2, dinitrogen (N2), water and some minerals (Paerl and Huisman 2009, Paerl and Otten 2013, Paerl et al.2016, 2001). Heterocysts are specialized nitrogen-fixing cells. Heterocysts have thick cell wall, do not pose photosynthetic membrane and are larger, clearer and highly refractive under light microscope appearance. They may occur within the filament of photosynthetic cells or terminally on a filament (Paerl and Huisman 2009, Paerl and Otten 2013, Paerl et al.2016, 2001). Due to the differences in size, shape and location of heterocysts, they form a significant component in species identification. Within the heterocysts, the enzyme nitrogenase reduces molecular nitrogen to ammonia, which is incorporated into the amido group of glutamine. The thickened cell wall enables molecular oxygen to enter the cell, to be reduced (Bryant 1994, Paerl et al.2016, 2001), thus helping to maintain a highly reducing environment within the cell, necessary for nitrogen reduction.