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[PMID]:28986298
[Au] Autor:Hsiao JC; McGrath AP; Kielmann L; Kalimuthu P; Darain F; Bernhardt PV; Harmer J; Lee M; Meyers K; Maher MJ; Kappler U
[Ad] Endereço:Centre for Metals in Biology, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, QLD 4072, Australia.
[Ti] Título:The central active site arginine in sulfite oxidizing enzymes alters kinetic properties by controlling electron transfer and redox interactions.
[So] Source:Biochim Biophys Acta;1859(1):19-27, 2018 01.
[Is] ISSN:0006-3002
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:A central conserved arginine, first identified as a clinical mutation leading to sulfite oxidase deficiency, is essential for catalytic competency of sulfite oxidizing molybdoenzymes, but the molecular basis for its effects on turnover and substrate affinity have not been fully elucidated. We have used a bacterial sulfite dehydrogenase, SorT, which lacks an internal heme group, but transfers electrons to an external, electron accepting cytochrome, SorU, to investigate the molecular functions of this arginine residue (Arg78). Assay of the SorT Mo centre catalytic competency in the absence of SorU showed that substitutions in the central arginine (R78Q, R78K and R78M mutations) only moderately altered SorT catalytic properties, except for R78M which caused significant reduction in SorT activity. The substitutions also altered the Mo-centre redox potentials (Mo potential lowered by ca. 60-80mV). However, all Arg78 mutations significantly impaired the ability of SorT to transfer electrons to SorU, where activities were reduced 17 to 46-fold compared to SorT , precluding determination of kinetic parameters. This was accompanied by the observation of conformational changes in both the introduced Gln and Lys residues in the crystal structure of the enzymes. Taking into account data collected by others on related SOE mutations we propose that the formation and maintenance of an electron transfer complex between the Mo centre and electron accepting heme groups is the main function of the central arginine, and that the reduced turnover and increases in K are caused by the inefficient operation of the oxidative half reaction of the catalytic cycle in enzymes carrying these mutations.
[Mh] Termos MeSH primário: Arginina/química
Proteínas de Bactérias/química
Sinorhizobium meliloti/enzimologia
Sulfito Desidrogenase/química
[Mh] Termos MeSH secundário: Substituição de Aminoácidos
Arginina/metabolismo
Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Domínio Catalítico
Transporte de Elétrons
Cinética
Molibdênio
Mutação de Sentido Incorreto
Oxirredução
Sinorhizobium meliloti/genética
Sulfito Desidrogenase/genética
Sulfito Desidrogenase/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Bacterial Proteins); 81AH48963U (Molybdenum); 94ZLA3W45F (Arginine); EC 1.8.2.1 (Sulfite Dehydrogenase)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171008
[St] Status:MEDLINE


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[PMID]:29369582
[Au] Autor:Muntyan VS; Cherkasova ME; Andronov EE; Simarov BV; Roumiantseva ML
[Ti] Título:[Occurrence of islands in genomes of Sinorhizobium meliloti native isolates].
[So] Source:Genetika;52(10):1126-33, 2016 Oct.
[Is] ISSN:0016-6758
[Cp] País de publicação:Russia (Federation)
[La] Idioma:rus
[Ab] Resumo:Genomes of 184 Sinorhizobium meliloti native isolates were studied to test the occurence of islands Sme21T, Sme19T, and Sme80S previously described in the model strain Rm1021. This analysis was conducted using PCR methodology involving specific primers. It was demonstrated that, in the examined geographically distinct populations of S. meliloti from the Northern Caucasus (NCG) and the Aral Sea region (PAG), the strains containing genomic islands were observed with similar frequency (0.55 and 0.57, respectively). Island Sme80S, denoted as an island of "environmental adaptivity," was identified predominantly (frequency of 0.38) in genomes of strains which exhibited a lower level of salt tolerance and was isolated in PAG, a modern center of introgressive hybridization of alfalfa subjected to salinity. Island Sme21T designated as "ancestral" was observed in genomes of strains isolated in NCG, the primary center of host-plant biodiversity, 10-fold more often than in strains from PAG. An island Sme19T, which predominantly carries genes encoding transposases, was observed in genomes of strains in both populations with average frequency of 0.10. The analysis of linkage disequilibrium (LD) based on the assessment of probability for detection of different islands combinations in genomes revealed an independent inheritance of islands in salt-sensitive strains of various geographic origin. In contrast, the absence of this trend was noted in the majority of the examined combinations of salt-tolerant strains. It was concluded that the structure of chromosome in PAG strains which predominantly possessed a salt-sensitive phenotype was subjected to active recombinant processes, which could predetermine the intensity of microevolutionary processes in bacterial populations and facilitate an adaptation of bacteria in adverse environmental effect.
[Mh] Termos MeSH primário: Genoma Bacteriano
Ilhas Genômicas
Desequilíbrio de Ligação
Sinorhizobium meliloti/genética
[Mh] Termos MeSH secundário: Sinorhizobium meliloti/isolamento & purificação
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180205
[Lr] Data última revisão:
180205
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180126
[St] Status:MEDLINE


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[PMID]:28686606
[Au] Autor:Hegazi NA; Sarhan MS; Fayez M; Patz S; Murphy BR; Ruppel S
[Ad] Endereço:Environmental Studies and Research Unit (ESRU), Department of Microbiology, Faculty of Agriculture, Cairo University, Giza, Egypt.
[Ti] Título:Plant-fed versus chemicals-fed rhizobacteria of Lucerne: Plant-only teabags culture media not only increase culturability of rhizobacteria but also recover a previously uncultured Lysobacter sp., Novosphingobium sp. and Pedobacter sp.
[So] Source:PLoS One;12(7):e0180424, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:In an effort to axenically culture the previously uncultivable populations of the rhizobacteria of Lucerne (Medicago sativa L.), we propose plant-only teabags culture media to mimic the nutritional matrix available in the rhizosphere. Here, we show that culture media prepared from Lucerne powder teabags substantially increased the cultivability of Lucerne rhizobacteria compared with a standard nutrient agar, where we found that the cultivable populations significantly increased by up to 60% of the total bacterial numbers as estimated by Quantitative Real-time Polymerase Chain Reaction (qRT-PCR). Cluster analysis of 16S rDNA Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) of cultivable Colony-Forming Units (CFUs) revealed a more distinct composition and separation of bacterial populations recovered on the plant-only teabags culture media than those developed on a standard nutrient agar. Further, the new plant medium gave preference to the micro-symbiont Sinorhizobium meliloti, and succeeded in isolating a number of not-yet-cultured bacteria, most closely matched to Novosphingobium sp., Lysobacter sp. and Pedobacter sp. The present study may encourage other researchers to consider moving from the well-established standard culture media to the challenging new plant-only culture media. Such a move may reveal previously hidden members of rhizobacteria, and help to further explore their potential environmental impacts.
[Mh] Termos MeSH primário: Técnicas de Cultura de Células/métodos
Medicago sativa/microbiologia
Rhizobiaceae/crescimento & desenvolvimento
Microbiologia do Solo
[Mh] Termos MeSH secundário: Meios de Cultura/farmacologia
Ecossistema
Lysobacter/efeitos dos fármacos
Lysobacter/crescimento & desenvolvimento
Pedobacter/efeitos dos fármacos
Pedobacter/crescimento & desenvolvimento
RNA Ribossômico 16S/genética
Rhizobiaceae/efeitos dos fármacos
Rizosfera
Sinorhizobium meliloti/efeitos dos fármacos
Sinorhizobium meliloti/crescimento & desenvolvimento
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Culture Media); 0 (RNA, Ribosomal, 16S)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171006
[Lr] Data última revisão:
171006
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170708
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0180424


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[PMID]:28416708
[Au] Autor:diCenzo GC; Sharthiya H; Nanda A; Zamani M; Finan TM
[Ad] Endereço:Department of Biology, McMaster University, Hamilton, Ontario, Canada.
[Ti] Título:PhoU Allows Rapid Adaptation to High Phosphate Concentrations by Modulating PstSCAB Transport Rate in Sinorhizobium meliloti.
[So] Source:J Bacteriol;199(18), 2017 Sep 15.
[Is] ISSN:1098-5530
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Maintenance of cellular phosphate homeostasis is essential for cellular life. The PhoU protein has emerged as a key regulator of this process in bacteria, and it is suggested to modulate phosphate import by PstSCAB and control activation of the phosphate limitation response by the PhoR-PhoB two-component system. However, a proper understanding of PhoU has remained elusive due to numerous complications of mutating , including loss of viability and the genetic instability of the mutants. Here, we developed two sets of strains of that overcame these limitations and allowed a more detailed and comprehensive analysis of the biological and molecular activities of PhoU. The data showed that cannot be deleted in the presence of phosphate unless PstSCAB is inactivated also. However, deletions were readily recovered in phosphate-free media, and characterization of these mutants revealed that addition of phosphate to the environment resulted in toxic levels of PstSCAB-mediated phosphate accumulation. Phosphate uptake experiments indicated that PhoU significantly decreased the PstSCAB transport rate specifically in phosphate-replete cells but not in phosphate-starved cells and that PhoU could rapidly respond to elevated environmental phosphate concentrations and decrease the PstSCAB transport rate. Site-directed mutagenesis results suggested that the ability of PhoU to respond to phosphate levels was independent of the conformation of the PstSCAB transporter. Additionally, PhoU-PhoU and PhoU-PhoR interactions were detected using a bacterial two-hybrid screen. We propose that PhoU modulates PstSCAB and PhoR-PhoB in response to local, internal fluctuations in phosphate concentrations resulting from PstSCAB-mediated phosphate import. Correct maintenance of cellular phosphate homeostasis is critical in all kingdoms of life and in bacteria involves the PhoU protein. This work provides novel insights into the role of the PhoU protein, which plays a key role in rapid adaptation to elevated phosphate concentrations. It is shown that PhoU rapidly responds to elevated phosphate levels by significantly decreasing the phosphate transport of PstSCAB, thereby preventing phosphate toxicity and cell death. Additionally, a new model for phosphate sensing in bacterial species which involves the PhoR-PhoB two-component system is presented. This work provides new insights into the bacterial response to changing environmental conditions and into regulation of the phosphate limitation response that influences numerous bacterial processes, including antibiotic production and virulence.
[Mh] Termos MeSH primário: Regulação Bacteriana da Expressão Gênica
Proteínas de Membrana Transportadoras/metabolismo
Fosfatos/metabolismo
Sinorhizobium meliloti/genética
Sinorhizobium meliloti/metabolismo
Fatores de Transcrição/metabolismo
[Mh] Termos MeSH secundário: Deleção de Genes
Proteínas de Membrana Transportadoras/genética
Mutagênese Sítio-Dirigida
Mapeamento de Interação de Proteínas
Fatores de Transcrição/genética
Técnicas do Sistema de Duplo-Híbrido
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Membrane Transport Proteins); 0 (Phosphates); 0 (Transcription Factors)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170906
[Lr] Data última revisão:
170906
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170419
[St] Status:MEDLINE


  5 / 1555 MEDLINE  
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[PMID]:28285657
[Au] Autor:Tang G; Wang S; Lu D; Huang L; Li N; Luo L
[Ad] Endereço:Shanghai Key Laboratory of Bio-energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China; School of Communication & Information Engineering, Shanghai University, Shanghai 200444, China.
[Ti] Título:Two-component regulatory system ActS/ActR is required for Sinorhizobium meliloti adaptation to oxidative stress.
[So] Source:Microbiol Res;198:1-7, 2017 May.
[Is] ISSN:1618-0623
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:The two-component system ActS/ActR plays important roles in bacterial adaptation to abiotic stress, including acid tolerance and oxidant resistance. However, the underlying regulatory mechanism is not clear. In this study, we found that the ActS/ActR system is required for adaptation to oxidative stress by regulating the transcription of the genes actR, katB, gshA and gshB1. The actS and actR mutants were sensitive to low pH and oxidants such as H O , oxidized glutathione (GSSG) and sodium nitroprusside (SNP). The expression of actR by using a plasmid rescued the defect of SNP sensitivity for all actS and actR mutants. The expression of actS and actR were suppressed by treatment with H O . The expression of actS, actR, oxyR, katA and katB was required for ActS and ActR under normal conditions. The induction of katB, gshA and gshB1 depended on ActS and ActR during treatment with H O and SNP. Our findings revealed that the ActS/ActR system is a key redox regulator in S. meliltoi and provides a new cue to understanding Rhizobium-legume symbiosis.
[Mh] Termos MeSH primário: Regulação Bacteriana da Expressão Gênica
Estresse Oxidativo
Transdução de Sinais
Sinorhizobium meliloti/genética
Sinorhizobium meliloti/fisiologia
Estresse Fisiológico
[Mh] Termos MeSH secundário: Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Deleção de Genes
Expressão Gênica
Teste de Complementação Genética
Concentração de Íons de Hidrogênio
Oxidantes/toxicidade
Oxirredução
Plasmídeos
Sinorhizobium meliloti/efeitos dos fármacos
Transcrição Genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Oxidants)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170413
[Lr] Data última revisão:
170413
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170314
[St] Status:MEDLINE


  6 / 1555 MEDLINE  
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[PMID]:28253454
[Au] Autor:Hawkins JP; Geddes BA; Oresnik IJ
[Ad] Endereço:Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
[Ti] Título:Common dyes used to determine bacterial polysaccharides on agar are affected by medium acidification.
[So] Source:Can J Microbiol;63(6):559-562, 2017 Jun.
[Is] ISSN:1480-3275
[Cp] País de publicação:Canada
[La] Idioma:eng
[Ab] Resumo:In this work, we highlight effects of pH on bacterial phenotypes when using the bacteriological dyes Aniline blue, Congo red, and Calcofluor white to analyze polysaccharide production. A study of galactose catabolism in Sinorhizobium meliloti led to the isolation of a mutation in dgoK1, which was observed to overproduce exopolysaccharides when grown in the presence of galactose. When this mutant strain was spotted onto plates containing Aniline blue, Congo red, or Calcofluor white, the intensity of the associated staining was strikingly different from that of the wild type. Additionally, a Calcofluor dull phenotype was observed, suggesting production of a polysaccharide other than succinoglycan. Further investigation of this phenotype revealed that these results were dependent on medium acidification, as buffering at pH 6 had no effect on these phenotypes, while medium buffered at pH 6.5 resulted in a reversal of the phenotypes. Screening for mutants of the dgoK1 strain that were negative for the Aniline blue phenotype yielded a strain carrying a mutation in tkt2, which is annotated as a putative transketolase. Consistent with the plate phenotypes, when this mutant was grown in broth cultures, it did not acidify its growth medium. Overall, this work shows that caution should be exercised in evaluating polysaccharide phenotypes based strictly on the use of dyes.
[Mh] Termos MeSH primário: Ágar
Corantes
Meios de Cultura/química
Polissacarídeos Bacterianos/análise
Sinorhizobium meliloti/química
[Mh] Termos MeSH secundário: Benzenossulfonatos/química
Concentração de Íons de Hidrogênio
Fenótipo
Sinorhizobium meliloti/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Benzenesulfonates); 0 (Coloring Agents); 0 (Culture Media); 0 (Polysaccharides, Bacterial); 73667-50-2 (succinoglycan); 7S9P0Y4313 (C.I. Fluorescent Brightening Agent 28); 9002-18-0 (Agar)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171025
[Lr] Data última revisão:
171025
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170303
[St] Status:MEDLINE
[do] DOI:10.1139/cjm-2016-0743


  7 / 1555 MEDLINE  
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[PMID]:28216096
[Au] Autor:León-Barrios M; Pérez-Yépez J; Dorta P; Garrido A; Jiménez C
[Ad] Endereço:Departamento de Bioquímica, Microbiología, Biología Celular y Genética, Universidad de La Laguna, 38200 La Laguna, Tenerife, Canary Islands, Spain. Electronic address: mileonba@ull.es.
[Ti] Título:Alkalinity of Lanzarote soils is a factor shaping rhizobial populations with Sinorhizobium meliloti being the predominant microsymbiont of Lotus lancerottensis.
[So] Source:Syst Appl Microbiol;40(3):171-178, 2017 Apr.
[Is] ISSN:1618-0984
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Lotus lancerottensis is an endemic species that grows widely throughout Lanzarote Island (Canary Is.). Characterization of 48 strains isolated from root nodules of plants growing in soils from eleven locations on the island showed that 38 isolates (79.1%) belonged to the species Sinorhizobium meliloti, whereas only six belonged to Mesorhizobium sp., the more common microsymbionts for the Lotus. Other genotypes containing only one isolate were classified as Pararhizobium sp., Sinorhizobium sp., Phyllobacterium sp. and Bradyrhizobium-like. Strains of S. meliloti were distributed along the island and, in most of the localities they were exclusive or major microsymbionts of L. lancerottensis. Phylogeny of the nodulation nodC gene placed the S. meliloti strains within symbiovar lancerottense and the mesorhizobial strains with the symbiovar loti. Although strains from both symbiovars produced effective N -fixing nodules, S. meliloti symbiovar lancerottense was clearly the predominant microsymbiont of L. lancerottensis. This fact correlated with the better adaptation of strains of this species to the alkaline soils of Lanzarote, as in vitro characterization showed that while the mesorhizobial strains were inhibited by alkaline pH, S. meliloti strains grew well at pH 9.
[Mh] Termos MeSH primário: Loteae/microbiologia
Rhizobium/classificação
Sinorhizobium meliloti/classificação
Microbiologia do Solo
Solo/química
Simbiose
[Mh] Termos MeSH secundário: Genes Bacterianos
Concentração de Íons de Hidrogênio
Tipagem de Sequências Multilocus
Fenótipo
Filogenia
RNA Ribossômico 16S/genética
Rhizobium/genética
Rhizobium/metabolismo
Tolerância a Sal/genética
Análise de Sequência de DNA
Sinorhizobium meliloti/genética
Sinorhizobium meliloti/metabolismo
Estresse Fisiológico
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (RNA, Ribosomal, 16S); 0 (Soil)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170221
[St] Status:MEDLINE


  8 / 1555 MEDLINE  
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[PMID]:28180335
[Au] Autor:Saramago M; Peregrina A; Robledo M; Matos RG; Hilker R; Serrania J; Becker A; Arraiano CM; Jiménez-Zurdo JI
[Ad] Endereço:Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República, Oeiras, Portugal.
[Ti] Título:Sinorhizobium meliloti YbeY is an endoribonuclease with unprecedented catalytic features, acting as silencing enzyme in riboregulation.
[So] Source:Nucleic Acids Res;45(3):1371-1391, 2017 02 17.
[Is] ISSN:1362-4962
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Structural and biochemical features suggest that the almost ubiquitous bacterial YbeY protein may serve catalytic and/or Hfq-like protective functions central to small RNA (sRNA)-mediated regulation and RNA metabolism. We have biochemically and genetically characterized the YbeY ortholog of the legume symbiont Sinorhizobium meliloti (SmYbeY). Co-immunoprecipitation (CoIP) with a FLAG-tagged SmYbeY yielded a poor enrichment in RNA species, compared to Hfq CoIP-RNA uncovered previously by a similar experimental setup. Purified SmYbeY behaved as a monomer that indistinctly cleaved single- and double-stranded RNA substrates, a unique ability among bacterial endoribonucleases. SmYbeY-mediated catalysis was supported by the divalent metal ions Mg2+, Mn2+ and Ca2+, which influenced in a different manner cleavage efficiency and reactivity patterns, with Ca2+ specifically blocking activity on double-stranded and some structured RNA molecules. SmYbeY loss-of-function compromised expression of core energy and RNA metabolism genes, whilst promoting accumulation of motility, late symbiotic and transport mRNAs. Some of the latter transcripts are known Hfq-binding sRNA targets and might be SmYbeY substrates. Genetic reporter and in vitro assays confirmed that SmYbeY is required for sRNA-mediated down-regulation of the amino acid ABC transporter prbA mRNA. We have thus discovered a bacterial endoribonuclease with unprecedented catalytic features, acting also as gene silencing enzyme.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Endorribonucleases/metabolismo
Sinorhizobium meliloti/metabolismo
[Mh] Termos MeSH secundário: Transportadores de Cassetes de Ligação de ATP/genética
Transportadores de Cassetes de Ligação de ATP/metabolismo
Substituição de Aminoácidos
Proteínas de Bactérias/química
Proteínas de Bactérias/genética
Sequência de Bases
Catálise
Cromossomos Bacterianos/genética
Endorribonucleases/química
Endorribonucleases/genética
Deleção de Genes
Perfilação da Expressão Gênica
Inativação Gênica
Genes Bacterianos
Genes Reporter
Fator Proteico 1 do Hospedeiro/genética
Fator Proteico 1 do Hospedeiro/metabolismo
Metaloproteínas/química
Metaloproteínas/genética
Metaloproteínas/metabolismo
Mutagênese Sítio-Dirigida
Conformação de Ácido Nucleico
Análise de Sequência com Séries de Oligonucleotídeos
Plasmídeos/genética
RNA Bacteriano/química
RNA Bacteriano/genética
RNA Bacteriano/metabolismo
Proteínas Recombinantes/química
Proteínas Recombinantes/genética
Proteínas Recombinantes/metabolismo
Sinorhizobium meliloti/genética
Especificidade por Substrato
Simbiose/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Host Factor 1 Protein); 0 (Metalloproteins); 0 (RNA, Bacterial); 0 (Recombinant Proteins); EC 3.1.- (Endoribonucleases)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171030
[Lr] Data última revisão:
171030
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170210
[St] Status:MEDLINE
[do] DOI:10.1093/nar/gkw1234


  9 / 1555 MEDLINE  
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[PMID]:28167519
[Au] Autor:Lagares A; Ceizel Borella; Linne U; Becker A; Valverde C
[Ad] Endereço:Laboratorio de Bioquímica, Microbiología e Interacciones Biológicas en el Suelo, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes-CONICET, Bernal, Argentina.
[Ti] Título:Regulation of Polyhydroxybutyrate Accumulation in Sinorhizobium meliloti by the -Encoded Small RNA MmgR.
[So] Source:J Bacteriol;199(8), 2017 04 15.
[Is] ISSN:1098-5530
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Riboregulation has a major role in the fine-tuning of multiple bacterial processes. Among the RNA players, -encoded untranslated small RNAs (sRNAs) regulate complex metabolic networks by tuning expression from multiple target genes in response to numerous signals. In , over 400 sRNAs are expressed under different stimuli. The sRNA MmgR (standing for akes ore ranules egulator) has been of particular interest to us since its sequence and structure are highly conserved among the alphaproteobacteria and its expression is regulated by the amount and quality of the bacterium's available nitrogen source. In this work, we explored the biological role of MmgR in 2011 by characterizing the effect of a deletion of the internal conserved core of ( ). This mutation resulted in larger amounts of polyhydroxybutyrate (PHB) distributed into more intracellular granules than are found in the wild-type strain. This phenotype was expressed upon cessation of balanced growth owing to nitrogen depletion in the presence of surplus carbon (i.e., at a carbon/nitrogen molar ratio greater than 10). The normal PHB accumulation was complemented with a wild-type copy but not with unrelated sRNA genes. Furthermore, the expression of limited PHB accumulation in the wild type, regardless of the magnitude of the C surplus. Quantitative proteomic profiling and quantitative reverse transcription-PCR (qRT-PCR) revealed that the absence of MmgR results in a posttranscriptional overexpression of both PHB phasin proteins (PhaP1 and PhaP2). Together, our results indicate that the widely conserved alphaproteobacterial MmgR sRNA fine-tunes the regulation of PHB storage in High-throughput RNA sequencing has recently uncovered an overwhelming number of -encoded small RNAs (sRNAs) in diverse prokaryotes. In the nitrogen-fixing alphaproteobacterial symbiont of alfalfa root nodules , only four out of hundreds of identified sRNA genes have been functionally characterized. Thus, uncovering the biological role of sRNAs currently represents a major issue and one that is particularly challenging because of the usually subtle quantitative regulation contributed by most characterized sRNAs. Here, we have characterized the function of the broadly conserved alphaproteobacterial sRNA gene in Our results strongly suggest that encodes a negative regulator of the accumulation of polyhydroxybutyrate, the major carbon and reducing power storage polymer in cells growing under conditions of C/N overbalance.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Hidroxibutiratos/metabolismo
RNA Bacteriano/metabolismo
Sinorhizobium meliloti/metabolismo
[Mh] Termos MeSH secundário: Proteínas de Bactérias/classificação
Proteínas de Bactérias/genética
Carbono/metabolismo
Proteínas de Ligação a DNA/classificação
Proteínas de Ligação a DNA/genética
Proteínas de Ligação a DNA/metabolismo
Regulação Bacteriana da Expressão Gênica/fisiologia
Mutação
Nitrogênio/metabolismo
Sinorhizobium meliloti/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (DNA-Binding Proteins); 0 (Hydroxybutyrates); 0 (PHAP protein, Bacteria); 0 (RNA, Bacterial); 7440-44-0 (Carbon); N762921K75 (Nitrogen)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:171031
[Lr] Data última revisão:
171031
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170208
[St] Status:MEDLINE


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[PMID]:28141492
[Au] Autor:Baumgardt K; Melior H; Madhugiri R; Thalmann S; Schikora A; McIntosh M; Becker A; Evguenieva-Hackenberg E
[Ad] Endereço:1​Institute of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany ‡â€‹Present address: CNRS, Institut de Biologie Physico-Chimique, 13 Rue Pierre et Marie Curie, 75005 Paris, France.
[Ti] Título:RNase E and RNase J are needed for S-adenosylmethionine homeostasis in Sinorhizobium meliloti.
[So] Source:Microbiology;163(4):570-583, 2017 Apr.
[Is] ISSN:1465-2080
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The ribonucleases (RNases) E and J play major roles in E. coli and Bacillus subtilis, respectively, and co-exist in Sinorhizobium meliloti. We analysed S. meliloti 2011 mutants with mini-Tn5 insertions in the corresponding genes rne and rnj and found many overlapping effects. We observed similar changes in mRNA levels, including lower mRNA levels of the motility and chemotaxis related genes flaA, flgB and cheR and higher levels of ndvA (important for glucan export). The acyl-homoserine lactone (AHL) levels were also higher during exponential growth in both RNase mutants, despite no increase in the expression of the sinI AHL synthase gene. Furthermore, several RNAs from both mutants migrated aberrantly in denaturing gels at 300 V but not under stronger denaturing conditions at 1300 V. The similarities between the two mutants could be explained by increased levels of the key methyl donor S-adenosylmethionine (SAM), since this may result in faster AHL synthesis leading to higher AHL accumulation as well as in uncontrolled methylation of macromolecules including RNA, which may strengthen RNA secondary structures. Indeed, we found that in both mutants the N6-methyladenosine content was increased almost threefold and the SAM level was increased at least sevenfold. Complementation by induced ectopic expression of the respective RNase restored the AHL and SAM levels in each of the mutants. In summary, our data show that both RNase E and RNase J are needed for SAM homeostasis in S. meliloti.
[Mh] Termos MeSH primário: Proteínas de Bactérias/genética
Endorribonucleases/genética
Regulação Bacteriana da Expressão Gênica
Metiltransferases/genética
S-Adenosilmetionina/metabolismo
Sinorhizobium meliloti/genética
Sinorhizobium meliloti/metabolismo
[Mh] Termos MeSH secundário: Transportadores de Cassetes de Ligação de ATP/genética
Flagelina/genética
Metilação
Percepção de Quorum
RNA Mensageiro/genética
RNA Mensageiro/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (RNA, Messenger); 0 (ndvA protein, Rhizobium meliloti); 12777-81-0 (Flagellin); 133606-66-3 (flaA protein, bacteria); 7LP2MPO46S (S-Adenosylmethionine); EC 2.1.1.- (Methyltransferases); EC 3.1.- (Endoribonucleases); EC 3.1.4.- (ribonuclease E)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171009
[Lr] Data última revisão:
171009
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170201
[St] Status:MEDLINE
[do] DOI:10.1099/mic.0.000442



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