Magnetic carbon composites as recycling electron shuttles on anaerobic biotransformations

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] The unique properties of magnetic nanoparticles (MNP), such as high surface area, magnetic, sorption and catalytic characteristics, make them very versatile for many applications in different areas including environmental remediation, as catalysts, adsorbents, immobilising agents for microorganisms and enzymes, and as supports for biofilm growth and water disinfectants. In order to improve their stability and to introduce additional surface properties and functionalities, MNP can be coated with carbon materials (CM) due to their chemical stability, biocompatibility and possibility of tailoring their textural and surface chemical properties for specific applications [1]. We have previously proved that various CM, including activated carbon, carbon xerogels and carbon nanotubes (CNT), can be used as redox mediators (RM) in anaerobic biotransformation, accelerating the electron transfer and, consequently, the reduction rates of organic compounds [1,2]. The combination of CM with MNP offers the possibility of creating magnetic carbon composites with synergistic properties: the adsorptive and catalytic properties of both and the magnetic character of MNP, improving the material performance and rendering it easier to be retained and recovered, by applying a magnetic field. [...]info:eu-repo/semantics/publishedVersio

Acceleration of methane production by carbon nanotubes

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] Carbon nanotubes and other conductive materials have been found to influence the rates of several anaerobic reactions. A range of different conductive carbon materials (CM) were reported to enhance methane production by anaerobic microbial communities. In most studies, the improvement of the overall process is attributed to the ability of these compounds to promote direct interspecies electron transfer (DIET) between bacteria, degrading more complex substrates, and methanogens, producing methane. The occurrence of DIET in the majority of these systems is not, however, proved and the effect of such conductive compounds on the activity of individual members, inside complex microbial communities, was never investigated. Thus, we herein present the results obtained when incubating pure cultures of methanogens, without any other microbial partner, in the presence of increasing concentrations of carbon nanotubes (CNT). Methane production from acetate, by the acetoclastic methanogens Methanosaeta concilii and Methanosarcina mazei, and from hydrogen plus carbon dioxide, by the hydrogenotrophic methanogens Methanospirillum hungatei and Methanobacterium formicicum, was accelerated, up to 17 times, in the presence of CNT [1]. Physical/chemical properties of the growth media changed in the presence of CNT, with redox potential decreasing with increasing CNT concentrations, and thus favouring methanogenesis. These findings show that CNT influences the microbial activity of methanogens in pure cultures and most likely this effect is extended to methanogens in complex communities as well, occurring in anaerobic bioreactors and in the environment. [...]info:eu-repo/semantics/publishedVersio

The complete genome sequence of Chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability

Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) ≈500 ORFs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) wide-spread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for the detoxification of xenobiotics that may have biotechnological applications

Revista de Ciências Médicas e Biológicas

As leucoplasias apresentam alte-rações epiteliais citológicas e estruturais denomina-das displasias. Tais lesões são freqüen-temente descritas como lesões com potencial para transformação em carcinomas espinocelulares bu-cais. A falta de consenso e a subjetividade quanto à classificação das displasias bucais está diretamente relacionada com a variabilidade inter e intra-observador. Face ao exposto, torna-se necessário um sistema fidedigno para a predição da progressão do câncer que viabilize um tratamento cada vez mais precoce. A identificação de eventos genéticos molecula-res importantes no desenvolvimento do carcinoma espinocelular bucal tor-nou possível à detecção de lesões que podem pro-gredir para malignidade. Isto traz a possibilidade de intervir eficientemente naqueles pacientes portadores de lesões precursoras em estágios precoces. Objetivo: O objetivo do artigo é discorrer sobre o tema leucoplasia bucal e suas formas de análise imunohistoquímica, além da apresentação de 2 casos clínicos analisados imunohistoquimicamente com o marcador CK 14, MIB, p53, p63 e Rb. Resultados: A expressão imunohistoquímica dos anticorpos Ck 14 e RB mostrou-se intensa e difusa em toda a espessura epitelial. As imunomarcações MIB e p53 apresentaram-se pouco intensas e restritas as células da camada basal do epitélio. Observou-se imunomarcação nuclear intensa e difusa da proteína p63 nas células epiteliais predominantemente na camada basal e células parabasais. Conclusão: Com base nos relatos desse trabalho foi possível observar que os marcadores de ciclo celular podem ajudar a iden-tificar a evolução de lesões cancerizáveis da cavidade bucal.Salvado

Leucoplasia: análise imunohistoquímica de 2 casos

As leucoplasias apresentam alte­rações epiteliais citológicas e estruturais denomina­das displasias. Tais lesões são freqüen­temente descritas como lesões com potencial para transformação em carcinomas espinocelulares bu­cais. A falta de consenso e a subjetividade quanto à classificação das displasias bucais está diretamente relacionada com a variabilidade inter e intra-observador. Face ao exposto, torna-se necessário um sistema fidedigno para a predição da progressão do câncer que viabilize um tratamento cada vez mais precoce. A identificação de eventos genéticos molecula­res importantes no desenvolvimento do carcinoma espinocelular bucal tor­nou possível à detecção de lesões que podem pro­gredir para malignidade. Isto traz a possibilidade de intervir eficientemente naqueles pacientes portadores de lesões precursoras em estágios precoces. Objetivo: O objetivo do artigo é discorrer sobre o tema leucoplasia bucal e suas formas de análise imunohistoquímica, além da apresentação de 2 casos clínicos analisados imunohistoquimicamente com o marcador CK 14, MIB, p53, p63 e Rb. Resultados: A expressão imunohistoquímica dos anticorpos Ck 14 e RB mostrou-se intensa e difusa em toda a espessura epitelial. As imunomarcações MIB e p53 apresentaram-se pouco intensas e restritas as células da camada basal do epitélio. Observou-se imunomarcação nuclear intensa e difusa da proteína p63 nas células epiteliais predominantemente na camada basal e células parabasais. Conclusão: Com base nos relatos desse trabalho foi possível observar que os marcadores de ciclo celular podem ajudar a iden­tificar a evolução de lesões cancerizáveis da cavidade bucal.

Synthesis, characterization and application of magnetic carbon materials as electron shuttles for the biological and chemical reduction of the azo dye Acid Orange 10

Supplementary data associated with this article can be found,in the online version, at http://dx.doi.org/10.1016/j.apcatb.2017.04.060.A set of core(ferrite, FeO)-shell(carbon, C) composites, C@FeO, C@MnFeO, C@CoFeO, and carbon nanotubes (CNT) impregnated with 2% of Fe (CNT@2%Fe) were prepared. The different composites were tested as redox mediators (RM) in the biological reduction of the azo dye Acid Orange 10 (AO10). Materials were tested at different concentrations from 0.1 to 1.0 g L1. In the absence of RM, the AO10 decolourisation after 24 h of reaction was only 30% at a rate of 0.2 d1. In the presence of the core-shell composites, better results were obtained with C@FeO materials at the amount of 1.0 g L1. The extent of AO10 decolourisation was above 90% and rate improved circa 29-fold. With CNT@2%Fe, the best efficiency (98 ± 3%) was achieved with 0.5 g L1 leading to a 79-fold rate increase. In abiotic controls, though at lower extent, the reduction of the dyes also occurred likely due to the electron transfer from Fe2+ to carbon and then to the dye. To prove this, assays combining single CNT and FeO materials were performed, and FeO had effect in the reaction only when combined with CNT. In the biological assay, the rate was the double and the percentage of decolourisation increased from (88 ± 6)% to (97 ± 1)%, when both materials were present in solution as compared with results in the presence of CNT alone. Under abiotic conditions, decolourisation occurred only in the presence of both materials, with a final percentage of (54 ± 2)%. Owing to their magnetic character, materials were removed from the media and successfully applied in successive cycles.This work was supported by the exploratory EXPL/AAG-TEC/0898/2013 financed by the Portuguese Foundation for Scienceand Technology (FCT). Acknowledges also to FCT under thescope of the strategic funding of UID/BIO/04469/2013 unit andCOMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorteoperation (NORTE-01-0145-FEDER-000004) funded by EuropeanRegional Development Fund under the scope of Norte2020 –Programa Operacional Regional do Norte; to the project “AIProc-Mat@N2020 – Advanced Industrial Processes and Materials fora Sustainable Northern Region of Portugal 2020”, with thereference NORTE-01-0145-FEDER-000006, supported by NortePortugal Regional Operational Programme (NORTE 2020), underthe Portugal 2020 Partnership Agreement, through the EuropeanRegional Development Fund (ERDF) and to Project POCI-01-0145-FEDER-006984–Associate Laboratory LSRE-LCM funded by ERDF through COMPETE2020 – Programa Operacional Competitividadee Internacionalizac¸ ão (POCI) – and by national funds through FCT -Fundação para a Ciência e a Tecnologia.Luciana Pereira a post-doc fellowship (SFRH/BPD/110235/2015) from FCT.info:eu-repo/semantics/publishedVersio