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Microbial succession within an anaerobic sequencing batch biofilm reactor (ASBBR) treating cane vinasse at 55ºC

RIBAS, Maria Magdalena Ferreira; CHINALIA, Fabio Alexandre; POZZI, Eloisa; FORESTI, Eugenio
Fonte: Tecpar Publicador: Tecpar
Tipo: Artigo de Revista Científica
ENG
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The aim of this work was to investigate the anaerobic biomass formation capable of treating vinasse from the production of sugar cane alcohol, which was evolved within an anaerobic sequencing batch biofilm reactor (ASBBR) as immobilized biomass on cubes of polyurethane foam at the temperature of 55ºC. The reactor was inoculated with mesophilic granular sludge originally treating poultry slaughterhouse wastewater. The evolution of the biofilm in the polyurethane foam matrices was assessed during seven experimental phases which were thus characterized by the changes in the organic matter concentrations as COD (1.0 to 20.0 g/L). Biomass characterization proceeded with the examination of sludge samples under optical and scanning electron microscopy. The reactor showed high microbial morphological diversity along the trial. The predominance of Methanosaeta-like cells was observed up to the organic load of 2.5 gCOD/L.d. On the other hand, Methanosarcinalike microorganisms were the predominant archaeal population within the foam matrices at high organic loading ratios above 3.3 gCOD/L.d. This was suggested to be associated to a higher specific rate of acetate consumption by the later organisms.; Este trabalho investigou a formação de um biofilme anaeróbio capaz de tratar vinhaça da produção de álcool de cana-de-açúcar...

Structural characterization of exopolysaccharides from biofilm of a cariogenic streptococci

AIRES, Carolina P.; TENUTA, Livia M.; CARBONERO, Elaine R.; SASSAKI, Guilherme L.; IACOMINI, Marcello; CURY, Jaime A.
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Artigo de Revista Científica
ENG
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Soluble (EPS-SOL), as well as insoluble extracellular polysaccharide (EPS-INSOL), extracted from biofilm of Streptococcus mutans, were analyzed by nuclear magnetic resonance spectroscopy, methylation analysis, and a controlled Smith degradation. EPS-SOL was a branched alpha-glucan containing a (1 -> 6)-and (1 -> 3)-linkages. EPS-INSOL was a branched alpha-glucan with similar linkages, but with a (1 -> 3)-linked main-chain partially substituted at O-6 with Glcp-(1 -> 6)-Glcp-side chains. Biofilm EPS had a distinct chemical structure compared with those synthesized by plankton cells or by purified enzymes from S. mutans, which could indicate different mechanisms for its degradation. (C) 2011 Published by Elsevier Ltd.; CNPq[152302/2007-7]

Diversidade e análise quantitativa de microrganismos do dominio Archaea em amostras de biofilme subgengival de individuos com periodontite agressiva e saúde periodontal.; Diversity and quantitative analysis of micoorganisms of Archaea domain in biofilm subgingival samples from aggressive periodontitis and periodontally healty subjects.

Matarazzo, Flávia
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 25/11/2010 PT
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Archaea ainda não foi reconhecido como patógeno de doença humana. O objetivo deste estudo foi determinar a prevalência, diversidade, níveis e proporções de Archaea no biofilme subgengival de indivíduos com periodontite agressiva (PA) e saúde periodontal (SP). Sessenta indivíduos foram selecionados para este estudo (n=30/grupo). A análise de diversidade foi realizada em 10 indivíduos/grupo. Quatro sítios/indivíduo do grupo PA e 2 sítios/indivíduo do grupo SP foram analisados por qPCR. A freqüência de Archaea foi de 60% dos indivíduos/ 15,2% dos sítios em PA e de 63,3% dos indivíduos/ 15,6% dos sítios em SP (p>0,05). Um a três filotipos foi identificado por amostra. O número de cópias e a proporção de Archaea e Bacteria foram menores no grupo SP do que no grupo PA (p<0,05). Archaea são encontrados no biofilme subgengival de indivíduos com PA e SP. Methanobrevibacter oralis é o filotipo mais prevalente, podendo ser considerado residente da cavidade bucal. A alteração ecológica na microbiota de indivíduos com PA inclui o aumento dos níveis e proporções de Archaea.; Membrers of Archaea domain may be detected in the microbiota of mucous surfaces of human and animals, but their association with diesase have not been yet stablished Some studies have suggested that Archaea domain may be indirectly associated with pathogenesis of periodontitis...

Avaliação da atividade de óleos essenciais sobre micro-organismos bucais e efeito de formulação de exaguatório bucal contendo óleo essencial sobre biofilme de micro-organismo cariogênio; Evaluation of essential oils activity against oral microorganisms and effect of mouthwash containing essential oil upon cariogenic microorganism biofilm

Sousa, Ingrid Pontes de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 04/07/2014 PT
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A utilização de enxaguatórios bucais é um recurso importante na manutenção da saúde oral, uma vez que esta pode suprir as limitações da higienização tradicional mecânica, devido ao maior acesso às bactérias do biofilme dental. Em função de sua fácil utilização, palatabilidade e poder de refrescância, os enxaguatórios podem ser considerados um produto de fácil adesão, sendo especialmente importantes na manutenção da saúde bucal de usuários com menor destreza ou impossibilidade de realizar uma escovação adequada. Entre os diversos componentes ativos que podem estar presentes nos enxaguatório bucais estão os constituintes de óleos essenciais como mentol, eucaliptol e timol. Uma grande vantagem da utilização de óleos essenciais em produtos para saúde bucal é a existência de uma gama de propriedades biológicas e organolépticas que os mesmos podem conferir às formulações, uma vez que podem atuar como agentes antimicrobianos, inibidores da produção de ácidos e sulfetos voláteis por bactérias orais, antioxidantes, anti-inflamatórios, aromatizantes e flavorizantes simultaneamente. Dessa forma, formulações contendo óleos essenciais podem ser potenciais agentes na prevenção e tratamento das afecções bucais mais comuns como a cárie dental...

Filmes de ormosils contendo polioxometalatos dopados com nanopartículas de titânia: adsorção de lipídeos e formação de biofilmes de Escherichia coli; Ormosils films containing polixomethalates doped with titania nanoparticles: lipids adsorption and biofilm formation of Escherichia coli

Souza, Luciana Valgas de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 16/06/2014 PT
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Neste trabalho foram preparados materiais híbridos do tipo silicatos organicamente modificados (ormosils) contendo fosfotungstato, [PW12O40]-3 e dopados com nanopartículas de TiO2. O objetivo é obter uma ação sinérgica destes dois fotocatalisadores na prevenção de formação de biofilmes e/ou sua fotodegradação. O fotocatalisador principal no sistema é o fosfotungstato, sendo o co-adjuvante o TiO2. Sendo assim, procurou-se manter a concentração deste no menor nível possível. Os materiais foram caracterizados por espectroscopias vibracionais, espectroscopia de fotoelétrons de raios X (XPS), Fluorescência de Raios X, Microscopia de força atômica e Microscopia eletrônica de varredura (MEV). Os filmes não mostraram eficácia na fotodegradação de biomoléculas como fosfolipídios encontrados na membrana celular. Os ensaios de inibição de crescimento de biofilmes de Escherichia coli sobre os ormosils mostraram que a maior inibição de bactérias é do filme contendo maior teor de nanopartículas de titânia portanto, são bons candidatos para filmes e revestimentos bactericidas/bacteriostáticos a serem usados em máscaras respiratórias, revestimentos de superfícies em salas de cirurgia e em filtros de ar em sistemas fechados (sistemas de ar condicionado e ventilação em geral).; This thesis deals with hybrid materials named organically modified silicates (Ormosils) with phosphotungstate...

Modulação do biofilme de Porphyromonas gingivalis pela associação com Streptococcus gordonii e com Prevotella intermedia.; Modulation of Porphyromonas gingivalis biofilm by association with Streptococcus gordonii and with Prevotella intermedia.

Higashi, Daniela
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 30/01/2015 PT
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P. gingivalis é um dos principais patógenos da doença periodontal, é encontrado em biofilmes orais com S. gordonii e P. intermedia e em células endoteliais da artéria coronária in vivo. P. gingivalis necessita de ferro em seu metabolismo e pode usar certas proteínas do hospedeiro como fontes deste íon em ambientes limitantes. Assim, este estudo investigou o papel dos genes PGN0741/PG0637 (receptor dependente de TonB) e PGN0531/PG1380 (fvW) de P. gingivalis na formação de biofilme em diferentes concentrações de ferro, em biofilmes mistos com S. gordonii e P. intermedia, e na adesão e invasão de células endoteliais da artéria coronária. Os resultados mostraram divergências no papel dos genes TonB e fvW na formação dos monobiofilmes e mistos e em diferentes concentrações de ferro, demonstrando uma relação cepa-dependente. Na adesão, fvW se mostrou importante para ambas cepas, mas na persistência apenas para P. gingivalis W83. Este trabalho enfatiza, assim, a necessidade do uso de mais de uma cepa de P. gingivalis no estudo do papel de genes em ensaios experimentais.; P. gingivalis is one of the major pathogens of periodontal diseases. It is found in oral biofilms associated with S. gordonii and P. intermedia...

Candida parapsilosis complex water isolates from a haemodialysis unit: biofilm production and in vitro evaluation of the use of clinical antifungals

Pires, Regina Helena; Santos, Jaime Maia dos; Zaia, José Eduardo; Martins, Carlos Henrique Gomes; Mendes Giannini, Maria José Soares
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: 646-654
ENG
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Candida parapsilosis, currently divided into three distinct species, proliferates in glucose-rich solutions and has been associated with infections resulting from the use of medical devices made of plastic, an environment common in dialysis centres. The aims of this study were (i) to screen for Candida orthopsilosis and Candida metapsilosis (100 environmental isolates previously identified as C. parapsilosis), (ii) to test the ability of these isolates to form biofilm and (iii) to investigate the in vitro susceptibility of Candida spp biofilms to the antifungal agents, fluconazole (FLC) and amphotericin B (AMB). Isolates were obtained from a hydraulic circuit collected from a haemodialysis unit. Based on molecular criteria, 47 strains were re-identified as C. orthopsilosis and 53 as C. parapsilosis. Analyses using a formazan salt reduction assay and total viable count, together with microscopy studies, revealed that 72 strains were able to form biofilm that was structurally similar, but with minor differences in morphology. A microtitre-based colorimetric assay used to test the susceptibility of fungal biofilms to AMB and FLC demonstrated that the C. parapsilosis complex displayed an increased resistance to these antifungal agents. The results from these analyses may provide a basis for implementing quality controls and monitoring to ensure the microbiological purity of dialysis water...

Candida species: Current epidemiology, pathogenicity, biofilm formation, natural antifungal products and new therapeutic options

Sardi, J. C. O.; Scorzoni, L.; Bernardi, T.; Fusco-Almeida, A. M.; Mendes Giannini, Maria José Soares
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 10-24
ENG
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The incidence of fungal infections has increased significantly, so contributing to morbidity and mortality. This is caused by an increase in antimicrobial resistance and the restricted number of antifungal drugs, which retain many side effects. Candida species are major human fungal pathogens that cause both mucosal and deep tissue infections. Recent evidence suggests that the majority of infections produced by this pathogen are associated with biofilm growth. Biofilms are biological communities with a high degree of organization, in which micro-organisms form structured, coordinated and functional communities. These biological communities are embedded in a self-created extracellular matrix. Biofilm production is also associated with a high level of antimicrobial resistance of the associated organisms. The ability of Candida species to form drugresistant biofilms is an important factor in their contribution to human disease. The study of plants as an alternative to other forms of drug discovery has attracted great attention because, according to the World Health Organization, these would be the best sources for obtaining a wide variety of drugs and could benefit a large population. Furthermore, silver nanoparticles, antibodies and photodynamic inactivation have also been used with good results. This article presents a brief review of the literature regarding the epidemiology of Candida species...

NaOCl effect on biofilm produced by Staphylococcus aureus isolated from the milking environment and mastitis infected cows

Melo, Poliana De Castro; Sousa, Cláudia; Botelho, Cláudia; Oliveira, Rosário; Nader-filho, Antonio
Fonte: Colégio Brasileiro de Patologia Animal - CBPA Publicador: Colégio Brasileiro de Patologia Animal - CBPA
Tipo: Artigo de Revista Científica Formato: 109-113
ENG
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Biofilms constitute a physical barrier, protecting the encased bacteria from detergents and sanitizers. The objective of this work was to analyze the effectiveness of sodium hypochlorite (NaOCl) against strains of Staphylococcus aureus isolated from raw milk of cows with subclinical mastitis and Staphylococcus aureus isolated from the milking environment (blowers and milk conducting tubes). The results revealed that, in the presence of NaOCl (150ppm), the number of adhered cells of the twelve S. aureus strains was significantly reduced. When the same strains were evaluated in biofilm condition, different results were obtained. It was found that, after a contact period of five minutes with NaOCl (150ppm), four strains (two strains from milk , one from the blowers and one from a conductive rubber) were still able to grow. Although with the increasing contact time between the bacteria and the NaOCl (150ppm), no growth was detected for any of the strains. Concerning the efficiency of NaOCl on total biofilm biomass formation by each S. aureus strain, a decrease was observed when these strains were in contact with 150 ppm NaOCl for a total period of 10 minutes. This study highlights the importance of a correct sanitation protocol of all the milk processing units which can indeed significantly reduce the presence of microorganisms...

The Relationship between Biofilm and Physical-Chemical Properties of Implant Abutment Materials for Successful Dental Implants

Avila, Erica Dorigatti de; Molon, Rafael Scaf de; Vergani, Carlos Eduardo; Mollo, Francisco de Assis; Salih, Vehid
Fonte: Mdpi Ag Publicador: Mdpi Ag
Tipo: Artigo de Revista Científica Formato: 3651-3662
ENG
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Processo FAPESP: 11/05106-6; The aim of this review was to investigate the relationship between biofilm and peri-implant disease, with an emphasis on the types of implant abutment surfaces. Individuals with periodontal disease typically have a large amount of pathogenic microorganisms in the periodontal pocket. If the individuals lose their teeth, these microorganisms remain viable inside the mouth and can directly influence peri-implant microbiota. Metal implants offer a suitable solution, but similarly, these remaining bacteria can adhere on abutment implant surfaces, induce peri-implantitis causing potential destruction of the alveolar bone near to the implant threads and cause the subsequent loss of the implant. Studies have demonstrated differences in biofilm formation on dental materials and these variations can be associated with both physical and chemical characteristics of the surfaces. In the case of partially edentulous patients affected by periodontal disease, the ideal type of implant abutments utilized should be one that adheres the least or negligible amounts of periodontopathogenic bacteria. Therefore...

Exploitation of a link between antibacterial agent-resistance and biofilm-formation by classical and emergent pathogens

João, Inês; Reis, Lúcia; Carvalho, Patrícia; Duarte, Aida; Jordão, Luisa
Fonte: Instituto Nacional de Saúde Doutor Ricardo Jorge, IP Publicador: Instituto Nacional de Saúde Doutor Ricardo Jorge, IP
Tipo: Conferência ou Objeto de Conferência
Publicado em /04/2013 ENG
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Objectives: In recent years nosocomial infections have gained growing importance. Among their etiological agents are “classical” pathogens such as S.aureus and also emergent pathogens, previously neglected, such as nontuberculous mycobacteria (MTM). The ability to resist to antibacterial agents, such as antibiotics and disinfectants, is shared by all of them. Here we aim to establish a link between bacterial virulence, antibacterial agents’ resistance and biofilm formation. Methods: Bacterial reference strains and clinical isolates were grown in adequate medium. Among the “classical” pathogens used are E.coli, K. pneumoniae, S. aureus and P. aeroginosa. The group of emergent pathogens includes M.fortuitum, M.abcessus, M.chelonae, M.avium etc. NTM susceptibility test to antibiotics was evaluated by broth based microdilution method and interpreted according to NCCLS guidelines. The desinfectant (oxygen peroxide, ammonium quaternary salts [AQS] and glutaraldehyde [GA) efficacy was performed according to the approved guidelines. The susceptibility was performed by two different methods: broth microdilution and diffusion in solid medium. In order to evaluate the effect of these agents in bacteria a scanning electron microscopy (SEM) study was performed. Biofilm forming ability was evaluated by the microtiter-plate test. The assay was performed at 25ºC and 37ºC in optimal growth media...

Biofilm establishment and heavy metal removal capacity of an indigenous mining algal-microbial consortium in a photo-rotating biological contactor

Orandi, S.; Lewis, D.; Moheimani, N.
Fonte: Nature America Inc Publicador: Nature America Inc
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
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An indigenous mining algal-microbial consortium was immobilised within a laboratory-scale photo-rotating biological contactor (PRBC) that was used to investigate the potential for heavy metal removal from acid mine drainage (AMD). The microbial consortium, dominated by Ulothrix sp., was collected from the AMD at the Sar Cheshmeh copper mine in Iran. This paper discusses the parameters required to establish an algal-microbial biofilm used for heavy metal removal, including nutrient requirements and rotational speed. The PRBC was tested using synthesised AMD with the multi-ion and acidic composition of wastewater (containing 18 elements, and with a pH of 3.5 ± 0.5), from which the microbial consortium was collected. The biofilm was successfully developed on the PRBC's disc consortium over 60 days of batch-mode operation. The PRBC was then run continuously with a 24 h hydraulic residence time (HRT) over a ten-week period. Water analysis, performed on a weekly basis, demonstrated the ability of the algal-microbial biofilm to remove 20-50 % of the various metals in the order Cu > Ni > Mn > Zn > Sb > Se > Co > Al. These results clearly indicate the significant potential for indigenous AMD microorganisms to be exploited within a PRBC for AMD treatment.; S. Orandi...

Aspergillus fumigatus biofilm on primary human sinonasal epithelial culture

Singhal, D.; Baker, L.; Wormald, P.J.; Tan, L.W.
Fonte: Ocean Side Publications Inc Publicador: Ocean Side Publications Inc
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
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BACKGROUND: Bacterial biofilms have been implicated in chronic rhinosinusitis (CRS). However, direct evidence in support of fungal biofilms in sinus disease is lacking in the literature. This study was designed to develop and characterize an in vitro Aspergillus fumigatus biofilm model on primary human sinonasal epithelial cell culture. METHODS: Sinonasal biopsy specimens harvested during endoscopic sinus surgery of six CRS patients and three pituitary tumor (control) patients were cultured in Dulbecco's modified Eagle media (DMEM; Invitrogen)/Hams F12 airway media to encourage epithelial cell proliferation. Epithelial cells separated by immunomagnetic beads were seeded in tissue culture-treated Y-shaped microslides. At confluence the primary cultures were inoculated with A. fumigatus spores. Fungus was allowed to germinate and form biofilms under two in vitro conditions: (1) static (no flow through of media) and (2) continuous flow coculture (continuous flow movement of media). At regular intervals cocultures were stained with FUN-1, concanavalin A-alexa fluor 488, and examined by confocal scanning laser microscopy. Comstat software was used to assess biomass and thickness. RESULTS: A. fumigatus formed three-dimensional biofilm structures with parallel-packed...

Biofilm formation and binding specificities of CFA/I, CFA/II and CS2 adhesions of Enterotoxigenic Escherichia coli and CfaE-R181A mutant

Liaqat,Iram
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2012 EN
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Enterotoxigenic Escherichia coli (ETEC) strains are leading causes of childhood diarrhea in developing countries. Adhesion is the first step in pathogenesis of ETEC infections and ETEC pili designated colonization factor antigens (CFAs) are believed to be important in the biofim formation, colonization and host cell adhesions. As a first step, we have determined the biofilm capability of ETEC expressing various types of pili (CFA/I, CfaE-R181A mutant/ CfaE tip mutant, CFA/II and CS2). Further, enzyme-linked immunosorbent assay (ELISA) assay were developed to compare the binding specificity of CFA/I, CFA/II (CS1 - CS3) and CS2 of ETEC, using extracted pili and piliated bacteria. CFA/II strain (E24377a) as well as extracted pili exhibited significantly higher binding both in biofilm and ELISA assays compared to non piliated wild type E24377a, CFA/I and CS2 strains. This indicates that co-expression of two or more CS2 in same strain is more efficient in increasing adherence. Significant decrease in binding specificity of DH5αF'lacIq/∆cotD (CS2) strain and MC4100/pEU2124 (CfaE-R181A) mutant strain indicated the important contribution of tip proteins in adherence assays. However, CS2 tip mutant strain (DH5αF'lacIq/pEU5881) showed that this specific residue may not be important as adhesions in these strains. In summary...

Evaluation of biofilm production by Pseudomonas Aeruginosa isolates recovered from cystic fibrosis and non-cystic fibrosis patients

Perez,L.R.R.; Costa,M.C.N.; Freitas,A.L.P.; Barth,A.L.
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2011 EN
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Cystic fibrosis (CF) patients typically suffer of persistent and recurrent lung infections caused by Pseudomonas aeruginosa that many times possess ability for the biofilm production. Here, biofilm production among P. aeruginosa isolates recovered from sputum of CF and non-CF patients was evaluated. Most isolates were biofilm-producing independently of the patient's condition.

Water-limiting conditions alter the structure and biofilm-forming ability of bacterial multispecies communities in the alfalfa rhizosphere.

Bogino, Pablo Cesar; Abod, Ayelen Selene; Nievas, Fiorela Lujan; Giordano, Walter Fabian
Fonte: Public Library Science Publicador: Public Library Science
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
ENG
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Biofilms are microbial communities that adhere to biotic or abiotic surfaces and are enclosed in a protective matrix of extracellular compounds. An important advantage of the biofilm lifestyle for soil bacteria (rhizobacteria) is protection against water deprivation (desiccation or osmotic effect). The rhizosphere is a crucial microhabitat for ecological, interactive, and agricultural production processes. The composition and functions of bacterial biofilms in soil microniches are poorly understood. We studied multibacterial communities established as biofilm-like structures in the rhizosphere of Medicago sativa (alfalfa) exposed to 3 experimental conditions of water limitation. The whole biofilm-forming ability (WBFA) for rhizospheric communities exposed to desiccation was higher than that of communities exposed to saline or nonstressful conditions. A culture-dependent ribotyping analysis indicated that communities exposed to desiccation or saline conditions were more diverse than those under the nonstressful condition. 16S rRNA gene sequencing of selected strains showed that the rhizospheric communities consisted primarily of members of the Actinobacteria and α- and γ-Proteobacteria, regardless of the water-limiting condition. Our findings contribute to improved understanding of the effects of environmental stress factors on plant-bacteria interaction processes and have potential application to agricultural management practices.; Fil: Bogino...

Characteristics of a methanogenic biofilm on sand particles in a fluidized bed reactor

Mussati,M.; Thompson,C.; Fuentes,M.; Aguirre,P.; Scenna,N.
Fonte: Latin American applied research Publicador: Latin American applied research
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2005 EN
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The typical microbiological groups reported in literature under the experienced environmental conditions are present in the biofilm structure investigated on sand particles. This is concluded based on microorganism morphology analyzed by scanning electron microscopy. Methanosarcina sp. (acetate consumers) and filamentous microorganisms with morphology similar to Methanospirillum sp. (H2-utilizing archaea) are distinguished among methanogens. Based on acetate levels and microorganism's threshold concentration, a predominance of Methanosarcina mazei rather than Methanosarcina barkeri is concluded. Among acetogens, bacillus morphologically similar to the syntrophic acetogenic Syntrophobacter wolinii are observed together with Desulfovibrio sp. (hydrogen-utilizing, sulfate-reducing). With respect to acidogens, short and long rod-shaped bacteria, diplococcus in chains (probably Streptococcus-like bacteria) and filamentous bacilli are morphologically distinguished but cannot be characterized from this study. A methanogenic biofilm fluidized bed reactor inoculated with the biofilm population investigated showed process efficiencies up to 98% of chemical oxygen demand reduction for treating an acetate-based substrate.

Aspects on methanogenic biofilm reactor modeling

Mussati,M. C.; Aguirre,P.; Fuentes,M.; Scenna,N.
Fonte: Latin American applied research Publicador: Latin American applied research
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2006 EN
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A previously developed deterministic steady state module for modeling methanogenic biofilm reactors has been revised to enlarge the model application range and to deal with system dynamics. Two models for the hydrolysis of non-active biomass representing extreme alternatives: without biomass hydrolysis (model A) and with complete and instantaneous hydrolysis of non-active suspended and attached biomass (model B) were investigated. Both models resulted to be suitable for simulating highly anaerobic loaded systems. However, only model B showed good agreement between experimental and calculated values at low organic loading rates. The values of the specific biofilm detachment rate and the specific microbial death rate of the original model were re-estimated for model B based on a set of step-type disturbances on the organic loading rates. At loading rates ranging between 2 to 4 g COD per day per liter of expanded bed applied to a lab-scale fluidized bed reactor, the parameter estimates were 0.0269 Lg-1d-1 and 0.061 d-1 for the specific biofilm detachment rate and the specific death rate, respectively, with a 95% chi-square confidence level.

Reduction of microbial biofilm formation using hydrophobic nano-silica coating on cooling tower fill material

Türetgen,Irfan
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2015 EN
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A cooling tower is a heat removal device, which extracts waste heat to the atmosphere through the cooling of a water stream to a lower temperature. Cooling towers are frequently associated with biofilm problems and Legionnaires disease outbreaks. Where biofilms can cause clogging and corrosion, reduction of biofilms is important for operational reasons and public health. Therefore, effective anti-biofilm strategies are needed in practice. The aim of the present study was to reduce biofilm formation using a nano-hydrophobic coating on cooling tower fill materials - polypropylene cooling tower fill material was coated with nano-silica. The effectiveness of the hydrophobic coating was investigated for a 6-month test period in a model cooling tower system, by monthly counting of the surface-associated bacteria using an epifluorescence microscope. A significant reduction (up to 4 log) in surface-associated bacteria was observed on coated test samples in comparison to uncoated control coupons. This study is the first report regarding the use of nano-silica coatings on cooling tower fills. The coating can be easily fabricated and the range of possible applications can be expanded to include a variety of conditions.

Enterotoxinas, biofilm y resistencia a los agentes antimicrobianos de cepas de Staphylococcus coagulasa negativa aisladas de hemocultivos

Nava Terán,Karelis Lilibeth; Sánchez Galvis,Dalialba María; Colina López,Gladis; Valero Leal,Kutchynskaya
Fonte: Universidad del Zulia Publicador: Universidad del Zulia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2013 ES
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Staphylococcus coagulasa negativa (SCN) es el microorganismo que se aísla con mayor frecuencia en los hemocultivos. Sin embargo, es poco el conocimiento que se tiene sobre los factores de virulencia producidos por SCN que contribuyen a la patogénesis de las infecciones causadas por estos microorganismos. El presente estudio se realizó para determinar la producción de enterotoxinas estafilocócicas, la producción de biofilm y la resistencia a los agentes antimicrobianos. Con este propósito, un total 48 cepas de SCN aisladas de hemocultivo en el Hospital Universitario de Maracaibo, Zulia, Venezuela fueron estudiadas. Las enterotoxinas estafilocócicas fueron detectadas por aglutinación en látex pasiva reversa. La producción de biofilm fue evaluada por un ensayo cuantitativo usando microplacas. La susceptibilidad contra los agentes antimicrobianos fue probada por el método de difusión del disco. Seis cepas (12,5%) aisladas de estafilococos fueron enterotoxigénicas. De estas, 3 fueron positivas para enterotoxina estafilocócica D (EED), 2 para enterotoxina estafilocócica A (EEA) y 1 de los aislamientos fueron positivos para enterotoxina estafilocócica B (EEB), enterotoxina estafilocócica C (EEC) y EED. Veintiuno de los aislamientos (44%) fueron productores de biofilm. Alta frecuencia de resistencia fue observada contra oxacilina (90%)...