Base de dados : MEDLINE
Pesquisa : B03.440.400.425.293.750 [Categoria DeCS]
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  1 / 37 MEDLINE  
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[PMID]:26544528
[Au] Autor:Seder-Colomina M; Morin G; Brest J; Ona-Nguema G; Gordien N; Pernelle JJ; Banerjee D; Mathon O; Esposito G; van Hullebusch ED
[Ad] Endereço:Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, 77454 Marne-la-Vallée, France.
[Ti] Título:Uranium(VI) Scavenging by Amorphous Iron Phosphate Encrusting Sphaerotilus natans Filaments.
[So] Source:Environ Sci Technol;49(24):14065-75, 2015 Dec 15.
[Is] ISSN:1520-5851
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:U(VI) sorption to iron oxyhydroxides, precipitation of phosphate minerals, as well as biosorption on bacterial biomass are among the most reported processes able to scavenge U(VI) under oxidizing conditions. Although phosphates significantly influence bacterially mediated as well as iron oxyhydroxide mediated scavenging of uranium, the sorption or coprecipitation of U(VI) with poorly crystalline nanosized iron phosphates has been scarcely documented, especially in the presence of microorganisms. Here we show that dissolved U(VI) can be bound to amorphous iron phosphate during their deposition on Sphaerotilus natans filamentous bacteria. Uranium LIII-edge EXAFS analysis reveals that the adsorbed uranyl ions share an equatorial oxygen atom with a phosphate tetrahedron of the amorphous iron phosphate, with a characteristic U-P distance of 3.6 Å. In addition, the uranyl ions are connected to FeO6 octahedra with U-Fe distances at ~3.4 Å and at ~4.0 Å. The shortest U-Fe distance corresponds to a bidentate edge-sharing complex often reported for uranyl adsorption onto iron oxyhydroxides, whereas the longest U-Fe and U-P distances can be interpreted as a bidentate corner-sharing complex, in which two adjacent equatorial oxygen atoms are shared with the vertices of a FeO6 octahedron and of a phosphate tetrahedron. Furthermore, based on these sorption reactions, we demonstrate the ability of an attached S. natans biofilm to remove uranium from solution without any filtration step.
[Mh] Termos MeSH primário: Compostos Férricos/química
Ferro/química
Sphaerotilus/química
Urânio/química
[Mh] Termos MeSH secundário: Adsorção
Biofilmes
Precipitação Química
Análise dos Mínimos Quadrados
Microscopia Eletrônica de Varredura
Minerais/química
Fosfatos/química
Espectrometria por Raios X
Urânio/isolamento & purificação
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Ferric Compounds); 0 (Minerals); 0 (Phosphates); 2UA751211N (ferric hydroxide); 4OC371KSTK (Uranium); E1UOL152H7 (Iron); N6BAA189V1 (ferric phosphate)
[Em] Mês de entrada:1607
[Cu] Atualização por classe:151215
[Lr] Data última revisão:
151215
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:151107
[St] Status:MEDLINE
[do] DOI:10.1021/acs.est.5b03148


  2 / 37 MEDLINE  
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[PMID]:25724989
[Au] Autor:Angelova R; Groudeva V; Slavov L; Iliev M; Nedkov I; Sziklai-László I; Krezhov K
[Ad] Endereço:Faculty of Biology, Sofia University "St. Kliment Ohridski", 8 Dragan Tsankov Blvd, 1164, Sofia, Bulgaria, raly_angelova@abv.bg.
[Ti] Título:Investigation of iron-containing products from natural and laboratory cultivated Sphaerotilus-Leptothrix bacteria.
[So] Source:J Biol Phys;41(4):367-75, 2015 Sep.
[Is] ISSN:1573-0689
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Bacterial biomass collected from sheath-forming bacteria of the genera Sphaerotilus and Leptothrix was collected from a high-mountain natural stream water source. The elemental constitution and oxide phases of the products after selective cultivation of the bacteria on two different elective media using neutron activation analysis (NAA), electron microscopy (SEM, TEM), and X-ray diffraction (XRD) were studied. A high enrichment level of iron was revealed by the NAA technique in cultivated isolates as compared to the reference sample from nature. Three types of iron oxide compounds were established after cultivation in Adler's medium: lepidocrocite (γ-FeOOH), magnetite (Fe3O4), and goethite (α-FeOOH). The cultivation in the Isolation medium yielded a single phase, that of goethite, excluding one sample with a distinguishable amount of lepidocrocite. XRD and EM investigations show that the biogenic oxides are nanosized. Our study exemplifies the possibilities of the biotechnology approach for obtaining, under artificial conditions, large quantities of iron-containing by-products that could be of further used in appropriate nano- and biotechnologies.
[Mh] Termos MeSH primário: Biomassa
Ferro/química
Laboratórios
Leptothrix/química
Leptothrix/crescimento & desenvolvimento
Sphaerotilus/química
Sphaerotilus/crescimento & desenvolvimento
[Mh] Termos MeSH secundário: Técnicas de Cultura
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
E1UOL152H7 (Iron)
[Em] Mês de entrada:1605
[Cu] Atualização por classe:160901
[Lr] Data última revisão:
160901
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150301
[St] Status:MEDLINE
[do] DOI:10.1007/s10867-015-9384-1


  3 / 37 MEDLINE  
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[PMID]:25666377
[Au] Autor:Seder-Colomina M; Goubet A; Lacroix S; Morin G; Ona-Nguema G; Esposito G; Van Hullebusch ED; Pernelle JJ
[Ad] Endereço:Laboratoire Géomatériaux et Environnement (LGE) (EA 4508), Institut Francilien des Sciences Appliquées, Université Paris-Est UPEM, Bât. IFI, 5 Boulevard Descartes - Champs sur Marne, 77454, Marne-la-vallée, Cedex 2, France, marina.sedercolomina@u-pem.fr.
[Ti] Título:Moderate oxygen depletion as a factor favouring the filamentous growth of Sphaerotilus natans.
[So] Source:Antonie Van Leeuwenhoek;107(5):1135-44, 2015 May.
[Is] ISSN:1572-9699
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Sphaerotilus natans is a neutrophilic iron-related sheath-forming filamentous microorganism that presents dual morphotype: single cells and ensheathed cells forming filaments. As S. natans has been proposed as a sorbent for inorganic pollutants and it is occasionally involved in bulking episodes, elucidating factors affecting its filamentous growth is of crucial interest. The purpose of this work was to evaluate the effect of dissolved oxygen (DO) as a factor affecting S. natans filamentation from single cells. A method to quantify S. natans in its filamentous and single-cell morphotypes, based on a differential filtration procedure coupled with quantitative real-time PCR, was developed here. Scanning Electron Microscopy was used to validate the filtration step. Under actively aerated conditions (DO maintained at 7.6 ± 0.1 mg l(-1)), S. natans grew mainly as single cells throughout the experiment, while a depletion in DO concentration (to ~3 mg l(-1)) induced its filamentous growth. Indeed, when oxygen was reduced the proportion of single cells diminished from 83.3 ± 5.9 to 14.3 ± 3.4% while the filaments increased from 16.7 ± 5.9 to 85.7 ± 3.4%. Our results suggest that oxygen plays a key role in S. natans filamentation and contribute to better understanding of the filamentous proliferation of this bacterium. In addition, the proposed method will be helpful to evaluate other factors favouring filamentous growth.
[Mh] Termos MeSH primário: Oxigênio/metabolismo
Sphaerotilus/crescimento & desenvolvimento
Sphaerotilus/metabolismo
[Mh] Termos MeSH secundário: Meios de Cultura/análise
Meios de Cultura/metabolismo
Oxigênio/análise
Reação em Cadeia da Polimerase em Tempo Real
Sphaerotilus/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Culture Media); S88TT14065 (Oxygen)
[Em] Mês de entrada:1601
[Cu] Atualização por classe:150407
[Lr] Data última revisão:
150407
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150211
[St] Status:MEDLINE
[do] DOI:10.1007/s10482-015-0405-7


  4 / 37 MEDLINE  
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[PMID]:25533039
[Au] Autor:Figueroa M; Val del Río A; Campos JL; Méndez R; Mosquera-Corral A
[Ad] Endereço:Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782, Santiago De Compostela, Galicia, Spain, monica.figueroa@usc.es.
[Ti] Título:Filamentous bacteria existence in aerobic granular reactors.
[So] Source:Bioprocess Biosyst Eng;38(5):841-51, 2015 May.
[Is] ISSN:1615-7605
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Filamentous bacteria are associated to biomass settling problems in wastewater treatment plants. In systems based on aerobic granular biomass they have been proposed to contribute to the initial biomass aggregation process. However, their development on mature aerobic granular systems has not been sufficiently studied. In the present research work, filamentous bacteria were studied for the first time after long-term operation (up to 300 days) of aerobic granular systems. Chloroflexi and Sphaerotilus natans have been observed in a reactor fed with synthetic wastewater. These filamentous bacteria could only come from the inoculated sludge. Thiothrix and Chloroflexi bacteria were observed in aerobic granular biomass treating wastewater from a fish canning industry. Meganema perideroedes was detected in a reactor treating wastewater from a plant processing marine products. As a conclusion, the source of filamentous bacteria in these mature aerobic granular systems fed with industrial effluents was the incoming wastewater.
[Mh] Termos MeSH primário: Bactérias/crescimento & desenvolvimento
Reatores Biológicos/microbiologia
Purificação da Água/métodos
[Mh] Termos MeSH secundário: Aerobiose
Animais
Biomassa
Chloroflexi/crescimento & desenvolvimento
Produtos Pesqueiros
Peixes
Indústria Alimentícia
Hibridização in Situ Fluorescente
Resíduos Industriais
Esgotos/microbiologia
Sphaerotilus/crescimento & desenvolvimento
Eliminação de Resíduos Líquidos
Águas Residuais
Poluentes Químicos da Água
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Industrial Waste); 0 (Sewage); 0 (Waste Water); 0 (Water Pollutants, Chemical)
[Em] Mês de entrada:1601
[Cu] Atualização por classe:150323
[Lr] Data última revisão:
150323
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:141224
[St] Status:MEDLINE
[do] DOI:10.1007/s00449-014-1327-x


  5 / 37 MEDLINE  
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[PMID]:25098830
[Au] Autor:Schmidt B; Sánchez LA; Fretschner T; Kreps G; Ferrero MA; Siñeriz F; Szewzyk U
[Ad] Endereço:Umweltmikrobiologie, Technische Universität Berlin, Berlin, Germany.
[Ti] Título:Isolation of Sphaerotilus-Leptothrix strains from iron bacteria communities in Tierra del Fuego wetlands.
[So] Source:FEMS Microbiol Ecol;90(2):454-66, 2014 Nov.
[Is] ISSN:1574-6941
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Sheath-forming iron- and manganese-depositing bacteria belonging to the Sphaerotilus-Leptothrix group (SLG) are widespread in natural and artificial water systems. Known requirements for their growth include the presence of organic substrates and molecular oxygen. High concentrations of reduced iron or manganese, although not necessary for most species, make their growth a noticeable phenomenon. Such microbial communities have been studied mostly in the Northern Hemisphere. Here, we present descriptions of diverse ochre-depositing microbial communities in Tierra del Fuego, Argentina, using a combined approach of microscopical examination, clone library construction and cultivation focused on SLG bacteria. To date, only few SLG type strains are available. The present work increases the number and diversity of cultivated SLG bacteria by obtaining isolates from biofilms and sediment samples of wetlands in Tierra del Fuego. Thirty isolates were selected based on morphological features such as sheath formation and iron/manganese deposition. Five operational taxonomic units (OTUs) were deduced. Sequencing of 16S rRNA genes showed that one OTU is identical to the Leptothrix mobilis Feox-1(T) -sequence while the four remaining OTUs show similarity values related to previously described type strains. Similarity values ranged from 96.5% to 98.8%, indicating possible new species and subspecies.
[Mh] Termos MeSH primário: Água Doce/microbiologia
Ferro/metabolismo
Leptothrix/isolamento & purificação
Microbiologia do Solo
Sphaerotilus/isolamento & purificação
Zonas Úmidas
[Mh] Termos MeSH secundário: Argentina
DNA Bacteriano/genética
Leptothrix/classificação
Leptothrix/genética
Leptothrix/metabolismo
Manganês/metabolismo
Dados de Sequência Molecular
RNA Ribossômico 16S/genética
Sphaerotilus/classificação
Sphaerotilus/genética
Sphaerotilus/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (DNA, Bacterial); 0 (RNA, Ribosomal, 16S); 42Z2K6ZL8P (Manganese); E1UOL152H7 (Iron)
[Em] Mês de entrada:1412
[Cu] Atualização por classe:141103
[Lr] Data última revisão:
141103
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140808
[St] Status:MEDLINE
[do] DOI:10.1111/1574-6941.12406


  6 / 37 MEDLINE  
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[PMID]:24965827
[Au] Autor:Park S; Kim DH; Lee JH; Hur HG
[Ad] Endereço:School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, Korea.
[Ti] Título:Sphaerotilus natans encrusted with nanoball-shaped Fe(III) oxide minerals formed by nitrate-reducing mixotrophic Fe(II) oxidation.
[So] Source:FEMS Microbiol Ecol;90(1):68-77, 2014 Oct.
[Is] ISSN:1574-6941
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Ferrous iron has been known to function as an electron source for iron-oxidizing microorganisms in both anoxic and oxic environments. A diversity of bacteria has been known to oxidize both soluble and solid-phase Fe(II) forms coupled to the reduction of nitrate. Here, we show for the first time Fe(II) oxidation by Sphaerotilus natans strain DSM 6575(T) under mixotrophic condition. Sphaerotilus natans has been known to form a sheath structure enclosing long chains of rod-shaped cells, resulting in a thick biofilm formation under oxic conditions. Here, we also demonstrate that strain DSM 6575(T) grows mixotrophically with pyruvate, Fe(II) as electron donors and nitrate as an electron acceptor and single cells of strain DSM 6575(T) are dominant under anoxic conditions. Furthermore, strain DSM 6575(T) forms nanoball-shaped amorphous Fe(III) oxide minerals encrusting on the cell surfaces through the mixotrophic iron oxidation reaction under anoxic conditions. We propose that cell encrustation results from the indirect Fe(II) oxidation by biogenic nitrite during nitrate reduction and that causes the bacterial morphological change to individual rod-shaped single cells from filamentous sheath structures. This study extends the group of existing microorganisms capable of mixotrophic Fe(II) oxidation by a new strain, S. natans strain DSM 6575(T) , and could contribute to biogeochemical cycles of Fe and N in the environment.
[Mh] Termos MeSH primário: Compostos Férricos/metabolismo
Compostos Ferrosos/metabolismo
Nitratos/metabolismo
Sphaerotilus/metabolismo
[Mh] Termos MeSH secundário: Minerais
Dados de Sequência Molecular
Nanoestruturas/ultraestrutura
Nitritos/metabolismo
Oxirredução
Sphaerotilus/ultraestrutura
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Ferric Compounds); 0 (Ferrous Compounds); 0 (Minerals); 0 (Nitrates); 0 (Nitrites); 1K09F3G675 (ferric oxide)
[Em] Mês de entrada:1501
[Cu] Atualização por classe:170220
[Lr] Data última revisão:
170220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140627
[St] Status:MEDLINE
[do] DOI:10.1111/1574-6941.12372


  7 / 37 MEDLINE  
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[PMID]:24701952
[Au] Autor:Ferreira V; Martins C; Pereira MO; Nicolau A
[Ti] Título:Use of an aerobic selector to overcome filamentous bulking in an activated sludge wastewater treatment plant.
[So] Source:Environ Technol;35(9-12):1525-31, 2014 May-Jun.
[Is] ISSN:0959-3330
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:An urban wastewater treatment plant (WWTP) with two different parallel lines of treatment and located in the north of Portugal was studied during four months, following recurrent episodes of filamentous bulking caused by Sphaerotilus natans and eventual occurrences of Nocardioforms and Type 1863. An aerobic selector was introduced in both lines in the beginning of the studied period, suppressed in one of the lines during six weeks, and then put into operation again until the end of the study. A total of 14 filamentous bacteria morphotypes were identified. The results showed that the presence of an aerobic biological selector in continuous operation prevented the overgrowth of the filamentous Type 1863, of Nocardioforms and, in particular, of S. natans. Simultaneously, it allowed lowering the oxygen levels in the aeration tanks without negative consequences in the overall performance of the WWTP, namely bulking occurrence. Dissolved oxygen (DO) in the aeration tank varied initially between 2 and 3 mg/L, but the introduction of the selector enabled to lower it to 1-1.5 mg/L in the aeration tank and around 0.5 mg/L in the selector. A significant energy save was allowed, even considering the aeration of the selector. The results are more relevant if one considers the fact that the main cause of the bulking problems in this WWTP was the overgrowth of S. natans, a filamentous bacterium known to be stimulated by low DO levels.
[Mh] Termos MeSH primário: Sphaerotilus/fisiologia
Gerenciamento de Resíduos
Águas Residuais/microbiologia
[Mh] Termos MeSH secundário: Aerobiose
[Pt] Tipo de publicação:EVALUATION STUDIES; JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Waste Water)
[Em] Mês de entrada:1405
[Cu] Atualização por classe:140407
[Lr] Data última revisão:
140407
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140408
[St] Status:MEDLINE


  8 / 37 MEDLINE  
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[PMID]:23330385
[Au] Autor:Eprintsev AT; Vu TL; Selivanova NV; Khasan Khamad A
[Ti] Título:[Obtaining homogenous preparations of succinate dehydrogenase isoforms from the D-507 strain of Sphaerotilus natans].
[So] Source:Prikl Biokhim Mikrobiol;48(6):600-5, 2012 Nov-Dec.
[Is] ISSN:0555-1099
[Cp] País de publicação:Russia (Federation)
[La] Idioma:rus
[Ab] Resumo:Enzymatic preparations of two isoforms of succinate dehydrogenase (SDG) with specific activity of 22.00 E/mg of protein were obtained from the colorless sulfur bacterium Sphaerotilus natans D-507 cultured organotrophically. Both SDG forms were shown to be heteromers with subunit molecular masses of 70.8, 35.0, 31.8, and 16.2 kDa. The K(m) values for the first and the second forms of SDG were evaluated as 0.615 and 0.531 mM, respectively, with an optimal pH value of 7.2. It was found that the Cl- ion has an activating effect on the SDG activity that can be explained by the specific chemical modification of the enzyme molecule. The results suggest that the isolated enzyme forms are included in different multienzyme complexes, which provide the functioning of the tricarboxylic acid cycle, and SDG preparations can be used for the investigation of other enzyme systems or in vitro modeling of supramolecular cellular structures.
[Mh] Termos MeSH primário: Proteínas de Bactérias/isolamento & purificação
Subunidades Proteicas/isolamento & purificação
Sphaerotilus/enzimologia
Succinato Desidrogenase/isolamento & purificação
[Mh] Termos MeSH secundário: Proteínas de Bactérias/química
Proteínas de Bactérias/metabolismo
Cloretos/química
Cloretos/metabolismo
Cromatografia em Gel
Ciclo do Ácido Cítrico/fisiologia
Eletroforese em Gel de Poliacrilamida
Ativação Enzimática
Concentração de Íons de Hidrogênio
Isoenzimas/química
Isoenzimas/isolamento & purificação
Isoenzimas/metabolismo
Cinética
Conformação Proteica
Multimerização Proteica
Subunidades Proteicas/química
Subunidades Proteicas/metabolismo
Sphaerotilus/química
Succinato Desidrogenase/química
Succinato Desidrogenase/metabolismo
[Pt] Tipo de publicação:ENGLISH ABSTRACT; JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Chlorides); 0 (Isoenzymes); 0 (Protein Subunits); EC 1.3.99.1 (Succinate Dehydrogenase)
[Em] Mês de entrada:1302
[Cu] Atualização por classe:130121
[Lr] Data última revisão:
130121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:130122
[St] Status:MEDLINE


  9 / 37 MEDLINE  
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[PMID]:23221712
[Au] Autor:Takeda M; Umezu T; Kawasaki Y; Shimura S; Kondo K; Koizumi J
[Ad] Endereço:Division of Materials Science and Chemical Engineering, Graduate School of Engineering, Yokohama National University, Yokohama, Japan. mtake@ynu.ac.jp
[Ti] Título:A spatial relationship between sheath elongation and cell proliferation in Sphaerotilus natans.
[So] Source:Biosci Biotechnol Biochem;76(12):2357-9, 2012.
[Is] ISSN:1347-6947
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Sphaerotilus natans is a filamentous sheath-forming bacterium. A method of selective fluorescent-labeling of its sheath using conventional reagents was developed. Terminal expansion of the sheath was confirmed by this method. In addition, ubiquitous cell growth was revealed by sequential phase-contrast microscopy of a filament. Based on this and earlier reports, a model of the sheath formation is proposed.
[Mh] Termos MeSH primário: Microtúbulos/metabolismo
Sphaerotilus/citologia
[Mh] Termos MeSH secundário: Proliferação Celular
Modelos Biológicos
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1306
[Cu] Atualização por classe:121227
[Lr] Data última revisão:
121227
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:121211
[St] Status:MEDLINE


  10 / 37 MEDLINE  
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[PMID]:22940182
[Au] Autor:Kondo K; Takeda M; Mashima T; Katahira M; Koizumi J; Ueda K
[Ad] Endereço:Graduate School of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama 240-8501, Japan.
[Ti] Título:Conformational analysis of an extracellular polysaccharide produced by Sphaerotilus natans.
[So] Source:Carbohydr Res;360:102-8, 2012 Oct 01.
[Is] ISSN:1873-426X
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Sphaerotilus natans is a filamentous sheath-forming bacterium, commonly found in bulking activated sludge. The bulky nature of this bacterium is caused by an extracellular polysaccharide (EPS). EPS is a linear acidic polysaccharide with the following chemical structure: [ → 4)-α-D-Glcp-(1 → 2)-ß-D-GlcpA-(1 → 2)-α-L-Rhap-(1 → 3)-ß-L-Rhap-(1 → ](n). (1)H-(1)H and (1)H-(13)C correlation nuclear magnetic resonance (NMR) experiments were performed to acquire nuclear Overhauser effect signals, which were used for conformational elucidation. Molecular mechanics calculations were performed on each disaccharide unit of the EPS building blocks. On the basis of the results of the calculations, the conformation of a pentasaccharide fragment was estimated. After confirmation of the coincidence between the NMR data and the predicted conformation of the pentasaccharide fragment, the conformation of a heptadecasaccharide fragment was estimated using the same procedure. The heptadecasaccharide was found to form a (12/1) helix and take locally folded chain, which is attributed to a triangular arrangement formed by a series of residues, α-D-Glcp-(1 → 2)-ß-D-GlcpA-(1 → 2)-α-L-Rhap. This arrangement is caused by the peculiar consecutive (1 → 2) linkages and reinforced by a hydrogen bond between the α-glucosyl and α-rhamnosyl residues. Considering the steric hindrance due to this triangular arrangement, EPS molecules are not supposed to form double helix in an aqueous environment. We propose the name 'sphaeran' to refer to this unique chemical structure and properties of EPS.
[Mh] Termos MeSH primário: Polissacarídeos/química
Sphaerotilus/química
[Mh] Termos MeSH secundário: Configuração de Carboidratos
Modelos Moleculares
Ressonância Magnética Nuclear Biomolecular
Polissacarídeos/biossíntese
Sphaerotilus/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Polysaccharides)
[Em] Mês de entrada:1311
[Cu] Atualização por classe:120914
[Lr] Data última revisão:
120914
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:120904
[St] Status:MEDLINE



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