351 research outputs found

    Oxygenated monoterpenes-rich volatile oils as potential antifungal agents for dermatophytes

    Get PDF
    Essential oils (EOs) extracted from Lavandula luisieri and Cymbopogon citratus were tested for their antifungal activity against ten clinical isolates of dermatophytes isolated from cases of tinea pedis. Inhibition of conidial germination and antifungal drug/EO combination assay were tested on two ATCC reference strains of Trichophyton rubrum and Trichophyton mentagrophytes. EOs were characterised by high amount of oxygenated monoterpenes in their composition. Strong antifungal activity was observed for the majority of clinical strains, and fungicidal activity was demonstrated. Positive interaction between L. luisieri EO combined with terbinafine was observed against terbinafine-resistant strain (Tr ATCC MYA-4438). Significative reduction of the germination was observed above 100 g mL1. Both oils were safe to macrophage mammalian cells at tested concentration. This study describes the antifungal activity of L. luisieri and C. citratus EOs against dermatophytes, which could be useful in designing new formulations for topical treatments.This work was supported by Portuguese Foundation for Science and Technology (FCT) [grant number PEST-C/FIS/UI607/2013], [grant number UID/BIO/04469/2013], [grant number PEst-OE/EQB/LA0023/2013] and European Community fund FEDER [grant number FCOMP-01-0124-FEDER-007025], [grant number RECI project: FCOMP-01-0124-FEDER-027462].The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013. Nicolina Dias acknowledges the project “Consolidating Research Expertise and Resources on Cellular and Molecular Biotechnology at CEB/IBB”, Ref. FCOMP-01-0124-FEDER-027462

    Structure, hardness and thermal stability of Ti(Al,N) coatings

    Get PDF
    In the past two decades, coatings of the Ti-Al-N ternary system have attracted considerable research and industrial interest. Nevertheless, the Ti-Al-N system still offers new interesting possibilities for coating developments such as the addition of low N contents to Ti-Al films in order to reach a good compromise between high hardness and a low friction coefficient.http://www.sciencedirect.com/science/article/B6TVV-4PNJ1JX-1S/1/164683ed052a9291c12494dc9255afd

    Use of ultramicroindentation to evaluate the degradation of sputtered coatings

    Get PDF
    The aim of this research work was to study the influence of chemical degradation on the mechanical properties of the non-degraded zones of sputtered W-N-Ti coatings. For this, an ultramicroindentation technique has been used before and after degradation, either on the zones between the pits in the corroded samples, or on the non-oxidised layers after removal of the top degraded layers. By using different applied loads it was possible to obtain results with and without the influence of the substrate. Thus, two types of results were obtained, those determined by using an empirical model, which eliminates the influence of the substrate, and those measured directly.Very small differences of less than 20% were obtained in the measured values before and after degradation, indicating that the non-degraded zones maintain their as-deposited mechanical properties.http://www.sciencedirect.com/science/article/B6TW4-3VGSFTN-Y/1/d6747ea11390bd13ea164c97933b791

    Lavandula luisieri and Lavandula viridis essential oils as upcoming anti-protozoal agents: A key focus on leishmaniasis

    Get PDF
    Background and objectives: Leishmania species is the causative agent of leishmaniasis, a broad-spectrum clinical condition that can even be life-threatening when neglected. Current therapeutic strategies, despite beings highly cost-effective, have been increasingly associated with the appearance of drug-resistant microorganisms. Thus, an increasing number of thorough studies are needed towards upcoming drug discovery. This study aims to reveal the anti-protozoa activity of Lavandula luisieri and Lavandula viridis essential oils (EO) and their main components (1,8-cineole, linalool, and borneol). Materials and Methods: L. luisieri and L. viridis EO and their main components' leishmanicidal effects were tested in vitro against Leishmania infantum, Leishmania major, and Leishmania tropica strains. Cell viability effects were estimated by using the tetrazolium-dye (MTT) colorimetric method, morphological changes were assessed by scanning electron microscopy (SEM) and ultrastructural investigation by transmission electronic microscopy (TEM). Phosphatidylserine externalization, mitochondrial membrane potential (MMP), and cathepsin D activity assessment were also carried out. Finally, cytotoxic activity of the studied matrices was also determined in mammalian cells. Results: Plant-studied EO exhibited prominent anti-Leishmania effects (IC50 = 31-263 ”g/mL), with L. luisieri being the most active one. At concentrations corresponding to IC50 values, EO-exposed L. infantum promastigotes suffered marked ultrastructural modifications. The presence of aberrant-shaped cells, mitochondrial and kinetoplast swelling, and autophagosomal structures were the most common evidenced changes. L. luisieri EO exerted its leishmanicidal activity through different mechanisms, but mainly through unleashing apoptosis. Phosphatidylserine externalization, mitochondrial membrane potential loss, and cell-cycle arrest at G(0)/G(1) phase were the most remarkable apoptosis-mediated aspects. Inhibition of cathepsin D activity was also observed. No toxic effects were found on macrophage cells. Conclusions: L. luisieri seems to be an upcoming source of bioactive molecules for leishmaniasis control and to find leading molecules for new drugs formulation against Leishmania infections.This work was supported by the European Regional Development Fund (ERDF), through the Centro 2020 Regional Operational Programme under project CENTRO-01-0145-FEDER-000008:BrainHealth 2020, and through the COMPETE 2020—Operational Programme for Competitiveness and Internationalisation and Portuguese national funds via FCT—Fundação para a CiĂȘncia e a Tecnologia, I.P., under strategic project POCI-01-0145-FEDER-007440 (UID/NEU/04539/2013). Acknowledgments: The authors are grateful to Jorge Paiva for helping in plant taxonomy; to JosĂ© Correia da Costa from Centro de Imunologia e Biologia ParasitĂĄria, Instituto Nacional Ricardo Jorge, Porto for supplying L. infantum (zymodeme MON-1); to AntĂłnio Osuna, Departamento de ParasitologĂ­a, Facultad de Ciencias, Instituto de BiotecnologĂ­a, Universidad de Granada, for supplying L. major. FCT for Strategic project ref. UID/BIM/04293/2013, and “NORTE2020—Programa Operacional Regional do Norte” (NORTE-01-0145-FEDER-000012)

    Evaluation of the anti-inflammatory, anti-catabolic and pro-anabolic effects of E-caryophyllene, myrcene and limonene in a cell model of osteoarthritis

    Get PDF
    Osteoarthritis is a progressive joint disease and a major cause of disability for which no curative therapies are yet available. To identify compounds with potential anti-osteoarthritic properties, in this study, we screened one sesquiterpene, E-caryophyllene, and two monoterpenes, myrcene and limonene, hydrocarbon compounds for anti-inflammatory, anti-catabolic and pro-anabolic activities in human chondrocytes. At non-cytotoxic concentrations, myrcene and limonene inhibited IL-1ÎČ-induced nitric oxide production (IC50=37.3ÎŒg/ml and 85.3”g/ml, respectively), but E-caryophyllene was inactive. Myrcene, and limonene to a lesser extent, also decreased IL-1ÎČ-induced NF-ÎșB, JNK and p38 activation and the expression of inflammatory (iNOS) and catabolic (MMP-1 and MMP-13) genes, while increasing the expression of anti-catabolic genes (TIMP-1 and -3 by myrcene and TIMP-1 by limonene). Limonene increased ERK1/2 activation by 30%, while myrcene decreased it by 26%, relative to IL-1ÎČ-treated cells. None of the compounds tested was able to increase the expression of cartilage matrix-specific genes (collagen II and aggrecan), but both compounds prevented the increased expression of the non-cartilage specific, collagen I, induced by IL-1ÎČ. These data show that myrcene has significant anti-inflammatory and anti-catabolic effects in human chondrocytes and, thus, its ability to halt or, at least, slow down cartilage destruction and osteoarthritis progression warrants further investigation

    Effect of endogenous methane production: a step forward in the validation of biochemical methane potential (BMP) tests

    Get PDF
    This work evaluates the influence of the inoculum type, the pre-consumption of the residual substrate and the ratio of blanks’ headspace volume to working volume (Hv Wv−1, 0.6 to 10) on Biochemical Methane Potential (BMP) measurements when methane is monitored by gas chromatography. Different inocula were tested: digested sewage sludge—DSS, granular sludge—GS and fresh dairy manure—DM. Microcrystalline cellulose was used as the substrate. BMP surpassed the maximum theoretical value (BMPmax=414 L kg−1) when methane produced in the blanks was not discounted, showing that degassing cannot stand alone as an alternative to the procedure of discounting the inoculum’s background production. Still, when the residual substrate concentration is high (e.g., in DM), degassing is mandatory because methane produced from its digestion will conceal the methane produced from the substrate in the BMP determination. For inocula with a low residual substrate (e.g., GS), short degassing periods are recommended in order to avoid detrimental effects on methanogenic activity. For moderate residual substrate concentrations (e.g., DSS), BMP values closer to BMPmax (90–97%) were achieved after degassing and discounting the blanks with lower Hv Wv−1. For higher Hv ∙ Wv−1, less accurate quantification occurred, likely due to error propagation. Proper inoculum pre-incubation time and discounting the methane production from blanks with low Hv Wv−1 (adjusted according to the estimated background methane) are essential for accurate BMP determinations.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit, and BioEcoNorte (NORTE 01-0145-FEDER-000070) funded by European Structural and Investment Funds under the scope of NORTE-45-2020-75—Sistema de Apoio à Investigação Científica e Tecnológica—“Projetos Estruturados de I&D&I”—HORIZONTE EUROPA. The research of J.V. Oliveira was supported by Ph.D. grant SFRH/BD/111911/2015 funded by FCT.info:eu-repo/semantics/publishedVersio

    Sustainable bioenergy carriers from wastes

    Get PDF
    The development of new technologies for renewable energy production is crucial for decreasing the reliance in fossil fuels and improving global sustainability. Waste materials are valuable resources that can be used for the production of energy carriers. Organic wastes can be anaerobically digested to ultimately produce methane. Hydrogen can be recovered from this process, if methanogenesis is inhibited. These energy carriers can also be derived from recalcitrant materials in a two step-process combining waste gasification and subsequent syngas bioconversion. Research carried out at our group focuses on the study of anaerobic processes for the production of energy-carriers using a multidisciplinary approach that combines both microbiological and technological aspects. Important achievements have been made within the anaerobic digestion of lipid-rich wastes. From our research, it became clear that lipids and LCFA-rich wastewater anaerobic treatment can be feasible with efficient methane recovery. Additionally, wastes containing fats and proteins, such as wastes from poultry industry, slaughterhouse and meat-processing industry have been assessed for methane production. Hydrolysis of cellulolytic and proteinaceous materials in solid wastes was enhanced using physicochemical pre-treatments and bioaugmentation, which is auspicious for optimal methane production. Sugar-rich wastes were used for assessing biohydrogen production and allowed the identification of critical aspects for methanogenesis inhibition. Immobilization of hydrogen-producing microorganisms in high rate continuous reactors was performed with good hydrogen recovery. Currently, we are studying the utilization of latex bionanocoatings for the entrapment of hydrogen-producing microorganisms as a means to improve cell immobilization. Another research area of expansion in our group is syngas fermentation to methane. Studies have been conducted on gas-liquid mass transfer for evaluating the potential of bioprocesses for syngas conversion. Concurrently, the physiology and microbiology of syngas-converting mixed cultures is also being assessed

    Spatial and temporal variability in coccolithophore abundance and distribution in the NW Iberian coastal upwelling system

    Get PDF
    A systematic investigation of the spatial and temporal variability in coccolithophore abundance and distribution through the water column of the NW Iberian coastal up-welling system was performed. From July 2011 to June 2012, monthly sampling at various water depths was conducted at two parallel stations located at 42 degrees N. Total coccosphere abundance was higher at the outer-shelf station, where warmer, nutrient-depleted waters favoured coccolithophore rather than phytoplanktonic diatom blooms, which are known to dominate the inner-shelf location. In seasonal terms, higher coccosphere and coccolith abundances were registered at both stations during upwelling seasons, coinciding with high irradiance levels. This was typically in conjunction with stratified, nutrient-poor conditions (i.e. relaxing upwelling conditions). However, it also occurred during some upwelling events of colder, nutrient-rich subsurface waters onto the continental shelf. Minimum abundances were generally found during downwelling periods, with unexpectedly high coccolith abundance registered in subsurface waters at the inner-shelf station. This finding can only be explained if strong storms during these downwelling periods favoured resuspension processes, thus remobilizing deposited coccoliths from surface sediments, and hence hampering the identification of autochthonous coccolithophore community structure. At both locations, the major coccolithophore assemblages were dominated by Emiliania huxleyi, small Gephyrocapsa group, Gephyrocapsa oceanica, Florisphaera profunda, Syracosphaera spp., Coronosphaera mediterranea, and Calcidiscus leptoporus. Ecological preferences of the different taxa were assessed by exploring the relationships between environmental conditions and temporal and vertical variability in coccosphere abundance. These findings provide relevant information for the use of fossil coccolith assemblages in marine sediment records, in order to infer past environmental conditions, of particular importance for Paleoceanography. Both E. huxleyi and the small Gephyrocapsa group are proposed as proxies for the upwelling regime with a distinct affinity for different stages of the upwelling event: E. huxleyi was associated with warmer, nutrient-poor and more stable water column (i.e. upwelling relaxation stage) while the small Gephyrocapsa group was linked to colder waters and higher nutrient availability (i.e. early stages of the upwelling event), similarly to G. oceanica. Conversely, F. profunda is suggested as a proxy for the downwelling regime and low-productivity conditions. The assemblage composed by Syracosphaera pulchra, Coronosphaera mediterranea, and Rhabdosphaera clavigera may be a useful indicator of the presence of subtropical waters conveyed northward by the Iberian Poleward Current. Finally, C. leptoporus is proposed as an indicator of warmer, saltier, and oligotrophic waters during the downwelling/winter regime.EXCAPA project - Xunta de Galicia [10MDS402013PR]; CALIBERIA project (Fundacao para a Ciencia e a Tecnologia - Portugal) [PTDC/MAR/102045/2008]; CALIBERIA project [COMPETE/FEDER-FCOMP-01-0124-FEDER-010599, BI/PTDC/MAR/102045/2008/2010-016, BI/PTDC/MAR/102045/2008/2010-022, BI/PTDC/MAR/102045/2008/2011-027]; Ministerio de Economia y Competitividad [CGL2015-68459-P]; Ministry of Education of Spain [AP2010-2559]; ETH Zurich Postdoctoral Fellowship from the Swiss Federal Institute of Technology in Zurich (ETHZ); Xunta de Galicia (Spain); FCT [SFRH/BPD/111433/2015]; Plurianual/Estrategico project [UID/Multi/04326/2013]info:eu-repo/semantics/publishedVersio

    The protective effect of Pseudomonas in syntrophic fatty acids degradation under microaerophilic conditions

    Get PDF
    Micro-aeration has been used in anaerobic digestion (AD) systems to improve some aspects of this multifunctional and flexible technology. The addition of vestigial amounts of oxygen is usually associated with an increase of the relative abundance of facultative anaerobic bacteria (FAB) in the microbial community. Besides being involved in fermentation/acidogenesis, FAB have been referred to act as a protective shield against the damaging effects of oxidative environments to the strict anaerobic organisms of these communities. The microbial relationships between FAB, syntrophic bacteria and methanogens were investigated, during the degradation of short (C4), medium (C8) and long (C16) chain fatty acids by two syntrophic cultures (Syntrophomonas species and a methanogenic partner) in the presence of facultative bacteria (two Pseudomonas sp.). Pseudomonas were added to the pre-grown syntrophic pair, along with the substrate and a range of O2 concentrations (0-10% v/v). The grown cultures then were transferred a second time, with the same substrate and to all the O2 conditions previously tested. The cultures were followed through CH4, VFA, LCFA and pH measurements. In the presence of O2 (up to 2%) an effective syntrophic relationship, as well as the maintenance of methanogenic activity, was only possible in the presence of FAB. Cultures exposed to O2 in the first incubation performed well when transferred back to anaerobic conditions. Moreover, at the second phase, Pseudomonas maintained its protective shield effect and most of the cultures previously developed under micro-aerobic conditions could also maintain its activity. This work demonstrates that the presence of Pseudomonas contributes for a more resilient and functional syntrophic consortium degrading fatty acids under micro-aerobic conditions.info:eu-repo/semantics/publishedVersio

    Ag-Ti(C,N)-based coatings for biomedical applications : influence of silver content on the structural properties

    Get PDF
    Ag–TiCN coatings were deposited by dc reactive magnetron sputtering and their structural and morphological properties were evaluated. Compositional analysis showed the existence of Ag–TiCN coatings with different Ag/Ti atomic ratios (ranging from 0 to 1.49). The structural and morphological properties are well correlated with the evolution of Ag/Ti atomic ratio. For the samples with low Ag/Ti atomic ratio (below 0.20) the coatings crystallize in a B1-NaCl crystal structure typical of TiC0.3N0.7. The increase in Ag/Ti atomic ratio promoted the formation of Ag crystalline phases as well as amorphous CNx phases detected in both x-ray photoelectron spectroscopy and Raman spectroscopy analysis. Simultaneously to the formation of Ag crystalline phases and amorphous carbon-based phases, a decrease in TiC0.3N0.7 grain size was observed as well as the densification of coatings.Spanish Ministry of Science and InnovationFundação para a CiĂȘncia e Tecnologia (FCT)CRUP InstitutionMCIN
    • 

    corecore