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https://www.readbyqxmd.com/read/29214973/expression-of-the-small-regulatory-rna-gene-mmgr-is-regulated-negatively-by-ania-and-positively-by-ntrc-in-sinorhizobium-meliloti-2011
#1
Germán Ceizel Borella, Antonio Lagares, Claudio Valverde
In the N2-fixing symbiont of alfalfa root nodules, Sinorhizobium meliloti 2011, the mmgR gene encodes a 77 nt small untranslated RNA (sRNA) that negatively regulates the accumulation of polyhydroxybutyrate (PHB) when the bacterium is grown under conditions of surplus carbon (C) in relation to nitrogen (N). We previously showed that the expression of mmgR is primarily controlled at the transcriptional level and that it depends on the cellular N status, although the regulatory mechanism and the factors involved were unknown...
December 7, 2017: Microbiology
https://www.readbyqxmd.com/read/29199214/-expression-of-two-rpoh-sigma-factors-in-sinorhizobium-meliloti-upon-heat-shock
#2
Hisayuki Mitsui, Kiwamu Minamisawa
The plant symbiotic α-proteobacterium Sinorhizobium meliloti has two RpoH-type sigma factors, RpoH1 and RpoH2. The former induces the synthesis of heat shock proteins and optimizes interactions with the host. Using a Western blot analysis, we examined time course changes in the intracellular contents of these factors upon a temperature upshift. The RpoH1 level was relatively high and constant, suggesting that its regulatory role in the heat shock response is attained through the activation of the pre-existing RpoH1 protein...
December 2, 2017: Microbes and Environments
https://www.readbyqxmd.com/read/29191113/characterization-of-cis-4-hydroxy-d-proline-dehydrogenase-from-sinorhizobium-meliloti
#3
Seiya Watanabe, Daichi Morimoto, Fumiyasu Fukumori, Yasuo Watanabe
The hypO gene from Sinorhizobium meliloti, located within the trans-4-hydroxy-L-proline metabolic gene cluster, was first successfully expressed in the host Pseudomonas putida. Purified HypO protein functioned as a FAD-containing cis-4-hydroxy-D-proline dehydrogenase with a homomeric structure. In contrast to other known enzymes, significant activity for D-proline was found, confirming a previously proposed potential involvement in D-proline metabolism.
December 1, 2017: Bioscience, Biotechnology, and Biochemistry
https://www.readbyqxmd.com/read/29158240/novel-genes-and-regulators-that-influence-production-of-cell-surface-exopolysaccharides-in-sinorhizobium-meliloti
#4
Melanie J Barnett, Sharon R Long
Sinorhizobium meliloti is a soil-dwelling α-proteobacterium that engages in a nitrogen-fixing root nodule symbiosis with leguminous plants. Cell surface polysaccharides are important for both adapting to stresses in the soil and development of an effective symbiotic interaction. Among the polysaccharides characterized to date, the acidic exopolysaccharides EPS-I (succinoglycan) and EPS-II (galactoglucan) are particularly important for protection from abiotic stresses, biofilm formation, root colonization, and infection of plant roots...
November 20, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/29155157/synthesis-characterization-and-the-antifungal-activity-of-chitosan-derivatives-containing-urea-groups
#5
Jingjing Zhang, Wenqiang Tan, Zhenpeng Zhang, Yinping Song, Qing Li, Fang Dong, Zhanyong Guo
As an abundant and renewable polysaccharide, chitosan has been drawing broad attention due to its natural properties. For the further utilization of chitosan, chemical modification can be applied in improving its water solubility and the bioactivities. In this study, four chitosan derivatives were synthesized by the reaction of chloracetyl chitosan derivative with quaternary ammonium salt (CTCS) and urea groups bearing 4-amino-pyridine, including BCTCS, 2CBCTCS, 3CBCTCS, and 4CBCTCS. The structure characteristics of synthesized products were established based on FT-IR spectroscopy, (1)H NMR, and elemental analysis...
November 15, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29150514/sinorhizobium-meliloti-glutathione-reductase-is-required-for-both-redox-homeostasis-and-symbiosis
#6
Guirong Tang, Ningning Li, Yumin Liu, Liangliang Yu, Junhui Yan, Li Luo
Glutathione (L-γ-glutamyl-L-cysteinylglycine; GSH), one of the key antioxidants in Sinorhizobium meliloti, is required for the development of alfalfa (Medicago sativa) nitrogen-fixing nodules. Glutathione exists either in a reduced form (GSH) or an oxidized form (GSSG), and its content is regulated by two pathways in S. meliloti The first pathway is the de novo synthesis of glutathione from its constituent amino acids, namely, Glu, Cys, and Gly, catalyzed by γ-glutamyl cysteine synthetase (GshA) and glutathione synthetase (GshB)...
November 17, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29150498/identification-of-a-chez-like-gene-in-azorhizobium-caulinodans-a-key-gene-in-the-control-of-chemotaxis-and-colonization-of-the-host-plant
#7
Xiaolin Liu, Wei Liu, Yu Sun, Chunlei Xia, Claudine Elmerich, Zhihong Xie
Chemotaxis can provide bacteria with competitive advantages for survival in complex environments. The CheZ chemotaxis protein is a phosphatase, affecting the flagellar motor in Escherichia coli, by dephosphorylating the response regulator CheY-P protein responsible for clockwise rotation. A cheZ gene has been found in Azorhizobium caulinodans ORS571, in contrast to other rhizobial species studied so far. The CheZ protein in ORS571 has a conserved motif similar to that corresponding to the phosphatase active site in E...
November 17, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29124841/regulation-of-cysteine-residues-in-lsrb-proteins-from-sinorhizobium-meliloti-under-free-living-and-symbiotic-oxidative-stress
#8
Guirong Tang, Shenghui Xing, Sunjun Wang, Liangliang Yu, Xuan Li, Christian Staehelin, Menghua Yang, Li Luo
The development of legume nitrogen-fixing nodules is regulated by reactive oxygen species (ROS) produced by symbionts. Several regulators from Rhizobium are involved in ROS sensing. In a previous study, we found that Sinorhizobium meliloti LsrB regulates lipopolysaccharide production and is associated with H2 O2 accumulation in alfalfa (Medicago sativa) nodules. However, its underlying regulatory mechanism remains unclear. Here, we report that the cysteine residues in LsrB are required for adaptation to oxidative stress, gene expression, alfalfa nodulation and nitrogen fixation...
November 10, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/29121239/overproduction-of-s-meliloti-argc-n-acetyl-gamma-glutamyl-phosphate-reductase-promotes-growth-delay-and-inefficient-nodules
#9
Carmen Vargas-Lagunas, Yolanda Mora, Rafael Díaz, Gabriel Martínez-Batallar, Lourdes Girard, Sergio Encarnación, Humberto Peralta, Jaime Mora
argC encodes N-acetyl-gamma-glutamyl phosphate reductase, the enzyme that catalyzes the high-energy consuming third step in the arginine synthesis pathway. A comparative analysis revealed two translation start sites in argC from Sinorhizobium meliloti. To determine whether both protein versions are synthesized in the organism and their functional role, we obtained genetic constructs with one (1S) or two (2S) start sites, with promoters of low (pspeB) or high (plac) transcriptional rate. The constructs were transferred to the S...
November 7, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/29110071/retrieved-16s-rrna-and-nifh-sequences-reveal-co-dominance-of-bradyrhizobium-and-ensifer-sinorhizobium-strains-in-field-collected-root-nodules-of-the-promiscuous-host-vigna-radiata-l-r-wilczek
#10
Sughra Hakim, Babur S Mirza, Ahmad Zaheer, Joan E Mclean, Asma Imran, Sumera Yasmin, M Sajjad Mirza
In the present study, the relative distribution of endophytic rhizobia in field-collected root nodules of the promiscuous host mung bean was investigated by sequencing of 16S ribosomal RNA (rRNA) and nifH genes, amplified directly from the nodule DNA. Co-dominance of the genera Bradyrhizobium and Ensifer was indicated by 32.05 and 35.84% of the total retrieved 16S rRNA sequences, respectively, and the sequences of genera Mesorhizobium and Rhizobium comprised only 0.06 and 2.06% of the recovered sequences, respectively...
November 6, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/29076560/an-account-of-evolutionary-specialization-the-abcr-small-rnas-in-the-rhizobiales
#11
REVIEW
Lauren M Sheehan, Clayton C Caswell
The AbcR small RNAs (sRNAs) are a fascinating example of two highly conserved sRNAs that differ tremendously at the functional level amongst organisms. From their transcriptional activation to their regulatory capabilities, the AbcR sRNAs exhibit varying characteristics in three well-studied bacteria belonging to the Rhizobiales order: the plant symbiont Sinorhizobium meliloti, the plant pathogen Agrobacterium tumefaciens, and the animal pathogen Brucella abortus. This review outlines the similarities and differences of the AbcR sRNAs between each of these organisms, and discusses reasons as to why this group of sRNAs has diverged in their genetic organization and regulatory functions across species...
October 27, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/29051066/study-of-the-cys-his-bridge-electron-transfer-pathway-in-a-copper-containing-nitrite-reductase-by-site-directed-mutagenesis-spectroscopic-and-computational-methods
#12
Julio C Cristaldi, María C Gómez, Pablo J González, Felix M Ferroni, Sergio Dalosto, Alberto C Rizzi, María G Rivas, Carlos D Brondino
The Cys-His bridge as electron transfer conduit in the enzymatic catalysis of nitrite to nitric oxide by nitrite reductase from Sinorhizobium meliloti 2011 (SmNir) was evaluated by site-directed mutagenesis, steady state kinetic studies, UV-vis and EPR spectroscopic measurements as well as computational calculations. The kinetic, structural and spectroscopic properties of the His171Asp (H171D) and Cys172Asp (C172D) SmNir variants were compared with the wild type enzyme. Molecular properties of H171D and C172D indicate that these point mutations have not visible effects on the quaternary structure of SmNir...
October 16, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29050878/stable-symbiotic-nitrogen-fixation-under-water-deficit-field-conditions-by-a-stress-tolerant-alfalfa-microsymbiont-and-its-complete-genome-sequence
#13
Cintia Jozefkowicz, Silvina Brambilla, Romina Frare, Margarita Stritzler, Carlos Piccinetti, Mariana Puente, Carolina Andrea Berini, Pedro Reyes Pérez, Gabriela Soto, Nicolás Ayub
We here characterized the stress-tolerant alfalfa microsymbiont Sinorhizobium meliloti B401. B401-treated plants showed high nitrogen fixation rates under humid and semiarid environments. The production of glycine betaine in isolated bacteroids positively correlated with low precipitation levels, suggesting that this compound acts as a critical osmoprotectant under field conditions. Genome analysis revealed that strain B401 contains alternative pathways for the biosynthesis and uptake of glycine betaine and its precursors...
October 16, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/29049366/transgenic-expression-of-antimicrobial-peptide-d2a21-confers-resistance-to-diseases-incited-by-pseudomonas-syringae-pv-tabaci-and-xanthomonas-citri-but-not-candidatus-liberibacter-asiaticus
#14
Guixia Hao, Shujian Zhang, Ed Stover
Citrus Huanglongbing (HLB) associated with 'Candidatus Liberibacter asiaticus' (Las) and citrus canker disease incited by Xanthomonas citri are the most devastating citrus diseases worldwide. To control citrus HLB and canker disease, we previously screened over forty antimicrobial peptides (AMPs) in vitro for their potential application in genetic engineering. D2A21 was one of the most active AMPs against X. citri, Agrobacterium tumefaciens and Sinorhizobium meliloti with low hemolysis activity. Therefore, we conducted this work to assess transgenic expression of D2A21 peptide to achieve citrus resistant to canker and HLB...
2017: PloS One
https://www.readbyqxmd.com/read/28990486/nodule-specific-cysteine-rich-peptides-negatively-regulate-nitrogen-fixing-symbiosis-in-a-strain-specific-manner-in-medicago-truncatula
#15
Qi Wang, Jinge Liu, Hua Li, Shengming Yang, Peter Körmöczi, Attila Kereszt, Hongyan Zhu
Medicago truncatula shows a high level of specificity when interacting with its symbiotic partner Sinorhizobium meliloti. This specificity is mainly manifested at the nitrogen-fixing stage of nodule development, such that a particular bacterial strain forms nitrogen-fixing nodules (Nod+/Fix+) on one plant genotype but ineffective nodules (Nod+/Fix-) on another. Recent studies have just begun to reveal the underlying molecular mechanisms that control this specificity. The S. meliloti strain A145 induces the formation of Fix+ nodules on the accession DZA315...
October 9, 2017: Molecular Plant-microbe Interactions: MPMI
https://www.readbyqxmd.com/read/28978203/silver-engineered-nanomaterials-and-ions-elicit-species-specific-o2-consumption-responses-in-plant-growth-promoting-rhizobacteria
#16
Ricky W Lewis, Jason Unrine, Paul M Bertsch, David H McNear
Metal containing engineered nanomaterials (ENMs) are now commonly used in various industrial and commercial applications. Many of these materials can be transformed during waste water treatment and ultimately enter terrestrial ecosystems via agriculturally applied biosolids. It is unclear how agriculturally important soil microbes will be affected by exposure to environmentally relevant, sublethal concentrations of ENMs and their transformation products (i.e., ions, aggregates, etc.). A method was developed, which puts O2 consumption responses in terms of viability, and tested by examining the toxic effects of Ag(+), Zn(2+), and Ni(2+) ions on the plant growth promoting rhizobacterium (PGPR) Bacillus amyloliquefaciens GB03...
October 4, 2017: Biointerphases
https://www.readbyqxmd.com/read/28967174/the-nitrate-reduction-gene-cluster-components-exert-lineage-dependent-contributions-to-optimization-of-sinorhizobium-symbiosis-with-soybeans
#17
Li Xue Liu, Qin Qin Li, Yun Zeng Zhang, Yue Hu, Jian Jiao, Hui Juan Guo, Xing Xing Zhang, Biliang Zhang, Wen Xin Chen, Chang Fu Tian
Receiving nodulation and nitrogen fixation genes does not guarantee rhizobia an effective symbiosis with legumes. Here, variations in gene content were determined for three Sinorhizobium species showing contrasting symbiotic efficiency on soybeans. A nitrate-reduction gene cluster absent in S. sojae was found to be essential for symbiotic adaptations of S. fredii and S. sp. III. In S. fredii, the deletion mutation of the nap (nitrate reductase), instead of nir (nitrite reductase) and nor (nitric oxide reductase), led to defects in nitrogen-fixation (Fix(-) )...
October 2, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28945538/gellertiella-hungarica-gen-nov-sp-nov-a-novel-bacterium-of-the-family-rhizobiaceae-isolated-from-a-spa-in-budapest
#18
Erika Tóth, Sára Szuróczki, Zsuzsa Kéki, Károly Bóka, Tibor Szili-Kovács, Peter Schumann
A novel alphaproteobacterium, strain RAM11T, belonging to the family Rhizobiaceae was isolated from the pool water of a thermal bath in Budapest, Hungary. Based on the 16S rRNA gene sequence strain RAM11T shows the highest sequence similarity values to Ensifer adhaerens Casida A (97.44 %), to Ensifer (syn. Sinorhizobium) americanus CFNEI 156T (96.87 %) and to Rhizobium azooxidifex Po 20/26T (96.76 %). The new bacterium is strictly aerobic, its optimum growth occurs at 20-37 °C, between pH 7 and 9 and without NaCl...
September 25, 2017: International Journal of Systematic and Evolutionary Microbiology
https://www.readbyqxmd.com/read/28936222/the-soybean-rfg1-gene-restricts-nodulation-by-sinorhizobium-fredii-usda193
#19
Yinglun Fan, Jinge Liu, Shanhua Lyu, Qi Wang, Shengming Yang, Hongyan Zhu
Sinorhizobium fredii is a fast-growing rhizobial species that can establish a nitrogen-fixing symbiosis with a wide range of legume species including soybeans (Glycine max). In soybeans, this interaction shows a high level of specificity such that particular S. fredii strains nodulate only a limited set of plant genotypes. Here we report the identification of a dominant gene in soybeans that restricts nodulation with S. fredii USDA193. Genetic mapping in an F2 population revealed co-segregation of the underlying locus with the previously cloned Rfg1 gene...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28916561/succinate-transport-is-not-essential-for-symbiotic-nitrogen-fixation-by-sinorhizobium-meliloti-nor-rhizobium-leguminosarum
#20
Michael J Mitsch, George C diCenzo, Alison Cowie, Turlough M Finan
Symbiotic nitrogen fixation (SNF) is an energetically expensive process performed by bacteria during endosymbiotic relationships with plants. The bacteria require the plant to provide a carbon source for generation of reductant to power SNF. While C4-dicarboxylates (succinate, fumarate, malate) appear to be the primary, if not sole, carbon source provided to the bacteria, the contribution of each C4-dicarboxylate is not known. We address this issue using a genetic and systems-level analyses. Expression of a malate specific transporter (MaeP) in Sinorhizobium meliloti Rm1021 dct mutants unable to transport C4-dicarboxylates resulted in malate import rates up to 30% that of wild type...
September 15, 2017: Applied and Environmental Microbiology
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