Persister cells in a biofilm treated with a biocide

This study investigated the physiology and behaviour following treatment with ortho-phthalaldehyde (OPA), of Pseudomonas fluorescens in both the planktonic and sessile states. Steady-state biofilms and planktonic cells were collected from a bioreactor and their extracellular polymeric substances (EPS) were extracted using a method that did not destroy the cells. Cell structure and physiology after EPS extraction were compared in terms of respiratory activity, morphology, cell protein and polysaccharide content, and expression of the outer membrane proteins (OMP). Significant differences were found between the physiological parameters analysed. Planktonic cells were more metabolically active, and contained greater amounts of proteins and polysaccharides than biofilm cells. Moreover, biofilm formation promoted the expression of distinct OMP. Additional experiments were performed with cells after EPS extraction in order to compare the susceptibility of planktonic and biofilm cells to OPA. Cells were completely inactivated after exposure to the biocide (minimum bactericidal concentration, MBC ¼ 0.55 + 0.20 mM for planktonic cells; MBC ¼ 1.7 + 0.30 mM for biofilm cells). After treatment, the potential of inactivated cells to recover from antimicrobial exposure was evaluated over time. Planktonic cells remained inactive over 48 h while cells from biofilms recovered 24 h after exposure to OPA, and the number of viable and culturable cells increased over time. The MBC of the recovered biofilm cells after a second exposure to OPA was 0.58 + 0.40 mM, a concentration similar to the MBC of planktonic cells. This study demonstrates that persister cells may survive in biocide-treated biofilms, even in the absence of EPS.The authors acknowledge the financial support provided by the Operational Programme for Competitiveness Factors - COMPETE and by the FCT - Portuguese Foundation for Science and Technology through Project Bioresist - PTDC/EBB-EBI/105085/2008 and the PhD grant awarded to Lucia C. Simoes (SFRH/BD/31661/2006)

Antibacterial activity of phenyl isothiocyanate on Escherichia coli and Staphylococcus aureus

The present study has been aimed to assess the antibacterial effects of the glucosinolate hydrolysis product phenyl isothiocyanate (PITC) against Escherichia coli and Staphylococcus aureus. Aspects on the antibacterial mode of action of PITC have also been characterized, such as the changes on surface physicochemical characteristics and membrane damage. The minimum inhibitory concentration of PITC was 1000 µg/mL, for both bacteria. The antimicrobial potential of PITC was compared with selected antibiotics (ciprofloxacin, erythromycin, streptomycin, tetracycline and spectinomycin),that reported a moderate effect. The combination of PITC with ciprofloxacin and erythromycin against S.aureus exhibited a good antimicrobial efficacy, due to an additive effect (the diameter of inhibition zones increased from 30 to 40 mm for ciprofloxacin and almost the double for erythromycin). The other combinations reported unsatisfactory results against both bacteria. The study of the physiological changes induced by PITC action demonstrated the interaction between the electrophilic compound and the bacterial cells at several points that causes changes in membrane properties (decreases negative surface charge, increases surface hydrophilicity and electron donor characteristics). PITC was also found to disturb membrane function, as manifested by phenomena such as cellular disruption and loss of membrane integrity, triggering cell death.This work was supported by Operational Programme for Competitiveness Factors - COMPETE and by FCT - Portuguese Foundation for Science and Technology through Projects Bioresist - PTDC/EBB-EBI/105085/2008; Phytodisinfectants - PTDC/DTP-SAP/1078/2012; the PhD grant (SFRH/BD/63398/2009-Anabela Borges) and the Post-Doctoral grant (SFRH/BPD/81982/2011-Lucia C. Simoes)

Development of photocatalytic poly(vinylidenefluoride-trifluoroethylene)/TiO₂ porous membranes

Photocatalysis has become an attractive process to remove contaminants from aquatic environments1. Photocatalysis consists on the use of solar light to generate highly oxidizing species, most often the hydroxyl radical (•OH), to destroy harmful compounds 2. Catalysts are required in this process and, due to its significant oxidizing properties under UV irradiation, TiO2 is the most widely used photocatalyst [ref?=6]. One disadvantage of the UV/photocatalyst process is the fast recombination rate of the electron-hole pairs3. Doping the photocatalysts with other elements is an effective approach to overcome this problem[ref]. Nevertheless, one of the largest drawbacks of the use of photocatalyst particles is the recycling and reutilization of the nanoparticles, which is time consuming and requires expensive processes2. In order to overcome this drawback, TiO2 immobilization in several substrates (e.g. glass, zeolite, silica and ceramic) has been explored. This work reports the optimization and photocatalytic activity of poly(vinylidenefluoride - trifluoroethylene) (PVDF-TrFE)/TiO2 nanocomposites.Work supported by FEDER (FCT), project PEST-C/FIS/UI607/2011 and PEST-C/QUI/UIO686/2011 and Matepro – Optimizing Materials and Processes”, ref. NORTE-07-0124-FEDER-00003

Eco-friendly polymeric material for horticulture application

Poly(lactic acid) (PLA), was mixed with wood fibers, coffee grounds, fertilizer and a foaming agent to developed a ecofriendly material to be used in horticulture. The developed materials should have mechanical properties similar to PLA, increasing biodegradability and lower price. The materials were prepared by melt processing in an internal mixer at 190ºC and were characterized by several techniques. The mechanical properties of the bio-composites, measured by flexural tests, were similar to neat PLA even with a reduction of 40 wt. % of polymer. Biodegradation assessment by composting tests in aerobic environment demonstrated that the green materials developed exhibited higher biodegradability than PLA. Bio-composites containing wood fibers and fertilizer revealed to be the most suitable for horticulture application, since these can combine mechanical properties, biodegradability and fertilizer release. Moreover, this green material has two main advantages, it can be prepared using materials from natural resources and does not generate any residue after use

Morphological Aspects And Cox-2 Expression After Exposure To 780-nm Laser Therapy In Injured Skeletal Muscle: An In Vivo Study.

The effectiveness of low-level laser therapy in muscle regeneration is still not well known. To investigate the effects of laser irradiation during muscle healing. For this purpose, 63 rats were distributed to 3 groups: non-irradiated control group (CG); group irradiated at 10 J/cm(2) (G10); and group irradiated at 50 J/cm(2) (G50). Each group was divided into 3 different subgroups (n=7), and on days 7, 14 and 21 post-injury the rats were sacrificed. Seven days post-surgery, the CG showed destroyed zones and extensive myofibrillar degeneration. For both treated groups, the necrosis area was smaller compared to the CG. On day 14 post-injury, treated groups demonstrated better tissue organization, with newly formed muscle fibers compared to the CG. On the 21(st) day, the irradiated groups showed similar patterns of tissue repair, with improved muscle structure at the site of the injury, resembling uninjured muscle tissue organization. Regarding collagen deposition, the G10 showed an increase in collagen synthesis. In the last period evaluated, both treated groups showed statistically higher values in comparison with the CG. Furthermore, laser irradiation at 10 J/cm(2) produced a down-regulation of cyclooxygenase 2 (Cox-2) immunoexpression on day 7 post-injury. Moreover, Cox-2 immunoexpression was decreased in both treated groups on day 14. Laser therapy at both fluencies stimulated muscle repair through the formation of new muscle fiber, increase in collagen synthesis, and down-regulation of Cox-2 expression.18395-40

Auditory stimulation and cardiac autonomic regulation

Previous studies have already demonstrated that auditory stimulation with music influences the cardiovascular system. In this study, we described the relationship between musical auditory stimulation and heart rate variability. Searches were performed with the Medline, SciELO, Lilacs and Cochrane databases using the following keywords: "auditory stimulation", "autonomic nervous system", "music" and "heart rate variability". The selected studies indicated that there is a strong correlation between noise intensity and vagal-sympathetic balance. Additionally, it was reported that music therapy improved heart rate variability in anthracycline-treated breast cancer patients. It was hypothesized that dopamine release in the striatal system induced by pleasurable songs is involved in cardiac autonomic regulation. Musical auditory stimulation influences heart rate variability through a neural mechanism that is not well understood. Further studies are necessary to develop new therapies to treat cardiovascular disorders

Influence of Air-Drying Conditions on Quality, Bioactive Composition and Sensorial Attributes of Sweet Potato Chips

The drying process is an essential thermal process for preserving vegetables and can be used in developing dried products as healthy alternative snacks. The effects of air-drying conditions using a convection dryer with hot air at different temperatures (60°, 65°, 70°, 75°, and 80 °C, in the range 5–200 min, at a fixed air speed of 2.3 m/s) were tested on the quality of slices (2.0 ± 0.1 mm) of dried sweet potato (Bellevue PBR). For each time and temperature, drying condition, physicochemical parameters (moisture content, CIELab color, texture parameters, total phenolic and carotenoid contents) and a sensory evaluation by a panel at the last drying period (200 min) were assessed. Drying time was shown to have a more significant effect than temperature on the quality of dried sweet potato as a snack, except for carotenoid content. Given the raw tuber content, thermal degradation (p < 0.05) of total phenolic compounds (about 70%), regardless of tested conditions, contrasted with the higher stability of total carotenoids (<30%). The dried product, under optimal conditions (≥75 °C for 200 min), achieved a moisture content (≤10%) suitable for preservation, providing a crispy texture with favourable sensory acceptance and providing a carotenoid content similar to the raw product.info:eu-repo/semantics/publishedVersio

Interleaved Sequence RNNs for Fraud Detection

Payment card fraud causes multibillion dollar losses for banks and merchants worldwide, often fueling complex criminal activities. To address this, many real-time fraud detection systems use tree-based models, demanding complex feature engineering systems to efficiently enrich transactions with historical data while complying with millisecond-level latencies. In this work, we do not require those expensive features by using recurrent neural networks and treating payments as an interleaved sequence, where the history of each card is an unbounded, irregular sub-sequence. We present a complete RNN framework to detect fraud in real-time, proposing an efficient ML pipeline from preprocessing to deployment. We show that these feature-free, multi-sequence RNNs outperform state-of-the-art models saving millions of dollars in fraud detection and using fewer computational resources.Comment: 9 pages, 4 figures, to appear in SIGKDD'20 Industry Trac

Polyoxometalates as promoters of laccase-assisted reactions

A synergistic effect of polyoxometalate and laccase benzenediol:oxygen oxidoreductase, EC 1.10.3.2 has been observed in the aerobic oxidation of a hydrazonaphthalene type colorant. The considerable increase in the decolorization rate of Solophenyl Blue GL dye with the new catalytic system composed by laccase and heptamolybdopentovanadophosphate heteropolyanion, when compared with the treatment with enzyme or heteropolyanion alone, was tentatively explained by the redox mediation action of the heteropolyanion

Functionalized protein nanoemulsions by incorporation of chemically modified BSA

The incorporation of bioactive compounds in stealth nanoparticles or nanoemulsions enhances their half-life in systemic circulation and can overcome the problems associated with the free drug. Bovine serum albumin (BSA)-drug conjugates were produced with either methotrexate (MTX), a potent anticancer agent, or vancomycin (VCM), a potent antibiotic. Those conjugates were used to produce functionalized BSA nanoemulsions in a formulation composed by aqueous phase and organic phase. BSA-Folic acid (FA) conjugates were also produced allowing specific folate receptor (FR) mediated targeting of cancer cells (KB cell line). All conjugates had similar effects either in solution or in the form of nanoemulsions: BSA-MTX as anti-proliferative over Caco-2 cell line and BSA-VCM as lower minimum inhibitory concentration (MIC) comparatively to VCM solution on Staphylococcus aureus strain Newman. The production of nanoemulsions using BSA-drug conjugates for obtaining vectors loaded with stabilized drugs offers a good, flexible template for a wide range of medical applications.Ana Loureiro (SFRH/BD/81479/2011) holds a scholarship from Fundacao para a Ciencia e a Tecnologia (FCT). Goncalo J. L. Bernardes is a Royal Society University Research Fellow at the Department of Chemistry, University of Cambridge and an Investigador FCT at the Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa. This work has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement NMP4-LA-2009-228827 NANOFOL. This work was supported by FEDER through POFC - COMPETE and by Portuguese funds from FCT through the project PEst-OE/BIA/UI4050/2014