An alginate lyase functional coating catalysis-independent to prevent P. aeruginosa adhesion

Bacterial colonisation of indwelling devices remains a serious threat in clinical field as it is commonly associated to persistent infections, called biomaterial-associated infections (BAI). Pseudomonas aeruginosa is the most common gram-negative bacillus associated with BAI and its emergence as a nosocomial pathogen is a growing concern. This opportunistic pathogen can produce a capsule-like polysaccharide called alginate that contributes to mucoid biofilm structure and persistent nature of infections. Given alginate's contribution to bacterial virulence, it has long been considered as a promising target for interventional therapies. Alginate lyase, an enzyme able to degrade alginate, has been shown to detach mucoid biofilms from abiotic surfaces and increase their antibiotic susceptibility. In this work, a new approach for alginate lyase was explored. Instead of using this enzyme for the treatment of pre-established mucoid biofilms, the ability of alginate lyase to prevent P. aeruginosa adhesion to a surface was investigated. For that purpose, a polydopamine (pDA) dip-coating strategy was applied for functionalization of biomaterials with alginate lyase. Polycarbonate (PC) substrates were immersed in an alkaline solution of dopamine to form a thin layer of pDA and then transferred into a solution of alginate lyase. Surface characterization was performed with XPS, contact angle measurement and SEM. Two reference strains of P. aeruginosa, a mucoid strain (ATCC 39324) and a non-mucoid (27853) as well as four clinical isolates, were used to assess the anti-adhesive properties of the functional coatings. Surface characterization confirmed the successful and efficient grafting of alginate lyase onto pDA-coated PC substrates. Untreated PC substrates allowed the adhesion of both reference strains and most of bacteria were found alive on these surfaces. Polydopamine-coated substrates had no significant effect on bacterial adhesion compared to the unmodified substrates. Substrates functionalized with alginate lyase exhibited anti-adhesive properties, causing a significant inhibition of the mucoid strain adhesion. Interestingly, substrates immobilized with this enzyme also proved to inhibit the adhesion of the non-mucoid strain and pDA-coated PC substrates immobilized with heat-inactivated enzyme also prevented the attachment of both bacterial strains. These results suggested that alginate lyase immobilized on pDA-coated substrates was able to impair P. aeruginosa adhesion regardless its mucoid phenotype and therefore it could be applied in a different context than cystic fibrosis. For instance, this enzyme could be used to develop functional coatings able to prevent P. aeruginosa infections associated to biomaterials. To confirm this hypothesis, the attachment of 4 clinical strains of P. aeruginosa, isolated from peritoneal dialysis catheters, on alginate lyase functional coatings were also evaluated. Alginate lyase immobilized on the substrates impaired the attachment of the clinical strains with the exception of one as its adhesion to the unmodified PC was already low. In this work, the versatile chemistry of polydopamine was successfully exploited to functionalize biomaterial surfaces with alginate lyase to impart them with anti-adhesive properties. The antibacterial performance of these alginate functional coatings was catalysis-independent which highlights the importance of further studies to better understand its mechanism of action against P. aeruginosa strains

Transmission of OFDM wired-wireless quintuple-play services along WDM LR-PONs using centralized broadband impairment compensation

This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.20.013748 . Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law[EN] The simultaneous transmission of four orthogonal frequencydivision multiplexing (OFDM)-based signals used to provide quintuple-play services along wavelength division multiplexing (WDM) long-reach passive optical networks (LR-PONs) is demonstrated experimentally. Particularly, the transmission performance of custom signal bearing Gigabit Ethernet data, Worldwide Interoperability for Microwave Access, Long Term Evolution and Ultra Wideband (sub-bands 2 and 3) signals is evaluated for different LR-PONs reaches, considering single-wavelength andWDMtransmission, and using a centralized impairment compensation technique at the central office that is transparent to the services provided. It is shown that error vector magnitude-compliant levels are obtained for all the OFDM-based signals in WDM LR-PONs reaching 100 km and that negligible inter-channel crosstalk is obtained for a channel spacing of 100 GHz regardless the OFDM-based signal considered. The successful multi-format OFDM transmission along the 100 km-long WDM LR-PON is achieved in the absence of optical dispersion compensation or single sideband modulation, and it is enabled by the performance improvement provided by the centralized impairment compensation realized. © 2012 Optical Society of America.M. Morant's work was supported by FPU-MEC grant AP2007-01413. This work was also supported in part by the European FIVER-FP7-ICT-2009-4-249142 project and by Fundacao para a Ciencia e a Tecnologia from Portugal under the TURBO-PTDC/EEA-TEL/104358/2008 project.Alves, T.; Morant Pérez, M.; Cartaxo, A.; Llorente Sáez, R. (2012). Transmission of OFDM wired-wireless quintuple-play services along WDM LR-PONs using centralized broadband impairment compensation. Optics Express. 20(13):13748-13761. https://doi.org/10.1364/OE.20.013748S13748137612013Jia, Z., Yu, J., Ellinas, G., & Chang, G.-K. (2007). Key Enabling Technologies for Optical–Wireless Networks: Optical Millimeter-Wave Generation, Wavelength Reuse, and Architecture. Journal of Lightwave Technology, 25(11), 3452-3471. doi:10.1109/jlt.2007.909201Armstrong, J. (2009). OFDM for Optical Communications. Journal of Lightwave Technology, 27(3), 189-204. doi:10.1109/jlt.2008.2010061Cvijetic, N. (2012). OFDM for Next-Generation Optical Access Networks. Journal of Lightwave Technology, 30(4), 384-398. doi:10.1109/jlt.2011.2166375Shieh, W., & Athaudage, C. (2006). Coherent optical orthogonal frequency division multiplexing. Electronics Letters, 42(10), 587. doi:10.1049/el:20060561Alves, T., Morant, M., Cartaxo, A., & Llorente, R. (2011). Performance Comparison of OFDM-UWB Radio Signals Distribution in Long-Reach PONs Using Mach-Zehnder and Linearized Modulators. IEEE Journal on Selected Areas in Communications, 29(6), 1311-1320. doi:10.1109/jsac.2011.110618Llorente, R., Alves, T., Morant, M., Beltran, M., Perez, J., Cartaxo, A., & Marti, J. (2008). Ultra-Wideband Radio Signals Distribution in FTTH Networks. IEEE Photonics Technology Letters, 20(11), 945-947. doi:10.1109/lpt.2008.922329Alves, T., & Cartaxo, A. (2011). Distribution of Double-Sideband OFDM-UWB Radio Signals in Dispersion Compensated Long-Reach PONs. Journal of Lightwave Technology, 29(16), 2467-2474. doi:10.1109/jlt.2011.2160616Chow, C.-W., Yeh, C.-H., Wang, C.-H., Shih, F.-Y., Pan, C.-L., & Chi, S. (2008). WDM extended reach passive optical networks using OFDM-QAM. Optics Express, 16(16), 12096. doi:10.1364/oe.16.012096Tang, J. M., Lane, P. M., & Shore, K. A. (2006). Transmission performance of adaptively modulated optical OFDM signals in multimode fiber links. IEEE Photonics Technology Letters, 18(1), 205-207. doi:10.1109/lpt.2005.861631Duong, T.-N., Genay, N., Ouzzif, M., Le Masson, J., Charbonnier, B., Chanclou, P., & Simon, J. C. (2009). Adaptive Loading Algorithm Implemented in AMOOFDM for NG-PON System Integrating Cost-Effective and Low-Bandwidth Optical Devices. IEEE Photonics Technology Letters, 21(12), 790-792. doi:10.1109/lpt.2009.2016978Alves, T., & Cartaxo, A. (2009). Performance Degradation Due to OFDM-UWB Radio Signal Transmission Along Dispersive Single-Mode Fiber. IEEE Photonics Technology Letters, 21(3), 158-160. doi:10.1109/lpt.2008.200923

Serological evidence of Toscana virus infection in Portuguese patients.

SUMMARYToscana virus (TOSV) is an emergingPhlebovirusof growing interest as a human pathogen in the Mediterranean Basin. In Portugal, however, little is known about the prevalence of TOSV infection. The aim of this work was to perform a seroprevalence study in patients with requests for laboratory diagnosis of vector-borne viruses. A total of 538 patients with and without neurological signs from 2004 to 2008 were studied by in-house indirect immunofluorescence assay and commercial enzyme-linked immunosorbent assays. A prevalence of 4·2% for IgG antibodies was found in the group of patients with neurological signs. Five (3%) of these had recent infections. In the group with no neurological signs, the IgG prevalence was 1·3%. Two samples, belonging to two patients, were also confirmed with plaque reduction neutralization tests with the TOSV ISS. Phl.3 Italian strain. This work showed that TOSV is present and causing disease from north to south in Portugal. The probable circulation of different phlebovirus serotypes in Portugal emphasizes the need for further studies

Anaerobic biodegradability of meat-processing wastes: effect of physical, chemical and enzymatic pre-treatments

Methane is produced during the anaerobic degradation of greaves and rinds, two by-products of pig slaughter and meat-processing industry. However, although values of 914±37 and 664±35 m3 CH4 ton-1 waste (wet weight) respectively were obtained, the degradation rate in batch assays was slow and lasted between 25 and 30 days. Therefore, in order to assess the potential increase in the biodegradation rate and biodegradability of these substrates, physical (temperature), chemical (alkali) and enzymatic (lipase) pre-treatments were tested. Partial hydrolysis was achieved for all the conditions applied but the efficiency was higher in alkaline and enzymatic treatments. These conditions produced hydrolysates with higher soluble+colloidal COD, long-chain fatty acids and ammonia concentrations, comparatively with the other treatments applied. Enzymatic hydrolysis increased 14% the methane production potential of the rinds, and this increase was even higher (80%) when rinds were thermally treated before addition of the enzyme. With all other pre-treatments, anaerobic biodegradability of both wastes was not improved comparatively to the raw materials. Alkaline conditions induced a severe decreased (89%) of rinds’ biodegradability. Enzymatic pre-treatment appears to be a promising strategy for increasing methane production from meat-processing wastes

Biochemical Methane Potential of raw and pre-treated meat-processing wastes

Raw and pre-treated greaves and rinds, two meat-processing wastes, were assessed for biochemical methane potential (BMP). Combinations of temperature (25, 55, 70 and 120°C), NaOH (0.3 g g-1 waste volatile solids) and lipase from Candida rugosa (10 U g-1 fat) were applied to promote wastes hydrolysis, and the effect on BMP was evaluated. COD solubilisation was higher (66% for greaves; 55% for rinds) when greaves were pre-treated with NaOH at 55°C and lipase was added to rinds after autoclaving. Maximum fat hydrolysis (52-54%) resulted from NaOH addition, at 55°C for greaves and 25°C for rinds. BMP of raw greaves and rinds was 707±46 and 756±56 L CH4 (at standard temperature and pressure) kg-1 VS, respectively. BMP of rinds improved 25% by exposure to 70ºC; all other strategies tested had no positive effect on BMP of both wastes, and anaerobic biodegradability was even reduced by the combined action of base and temperature.The authors thank Cristiana Goncalves for her help with the enzymatic pre-treatments. The financial support from Portuguese Innovation Agency (ADI), through the project FatValue (QREN no. 3491), is gratefully acknowledged. Professor Giovana Tommaso thanks the EMUNDUS15 - Erasmus Mundus External Cooperation Window (Lot15) that provided financial support for her stay in the University of Minho, Portugal

Novel aziridine esters by the addition of aromatic nitrogen heterocycles to a 2H-azirine-3-carboxylic ester

Methyl 2-(2,6-dichlorophenyl)-2H-azirine-3-carboxoylate acts as an efficient alkylating agent for a variety of five-membered aromatic heterocycles. The aziridines derived from heterocycles that bear an alpha-carbonyl substituent react with TFA to give pyrroloimidazoles; 2,6-dichlorobenzaldehyde is also produced.- (undefined

Avaliação da presença de anticorpos IgG anti-Schistosoma mansoni no soro de pacientes com esquistossomose mansônica crônica, antes e após tratamento específico

The circumoval precipitin test (COPT), enzyme-linked immunosorbent assay (ELISA) and the immunoblotting anti-adult worm antigen (AWA) and soluble egg antigen (SEA) tests were applied to 17 chronically schistosome-infected patients for the detection of anti-Schistosoma mansoni antibodies before and on four occasions after oxamniquine administration over a period of six months. Compared to a control group, schistosomiasis patients showed high levels of IgG antibodies in AWA and SEA-ELISA. A decrease in IgG levels was observed six months after treatment, although negative reactions were not obtained. Significant decreases in IgG1, IgG3 and, mainly, IgG4, but not anti-SEA IgG2 levels were observed six months after treatment, again without negativity. Analysis of anti-AWA IgG antibodies by immunoblotting before treatment showed a 31 kDa strand in 14 patients (82%) which disappeared in three cases up to six months after treatment; furthermore, anti-SEA IgG antibodies showed the same band in nine patients (53%) before treatment, which disappeared in only four cases up to six months after treatment.Em 17 pacientes com infecção crônica por Schistosoma mansoni utilizaram-se os testes de reação periovular, imunoenzimático (ELISA) e imunoblotting, empregando-se antígenos obtidos a partir de vermes adultos (AWA) ou de ovos de S. mansoni (SEA), para detecção de anticorpos anti-S. mansoni, antes e em quatro ocasiões após tratamento com oxamniquine. Quando cotejados a grupo controle os pacientes esquistossomóticos revelaram altos níveis séricos de anticorpos IgG nos testes ELISA (anti-AWA e anti-SEA), não se observando, porém, negativação até seis meses após tratamento específico. Encontrou-se, entretanto, decréscimo significativo, sem negativação, dos níveis de IgG1, IgG3 e, principalmente, IgG4, quando se utilizou antígeno solúvel obtido a partir de ovos de S. mansoni (SEA), seis meses após administração de oxamniquine. O mesmo não foi observado no caso de anticorpos da subclasse IgG2. Nos imunoblottings efetuados com o emprego de antígeno de verme adulto (AWA), antes do tratamento com oxamniquine, evidenciou-se a presença de banda com 31 kDa em 14 (82%) dos 17 pacientes estudados, observando-se seu desaparecimento em três pacientes examinados seis meses após tratamento específico. Quando se utilizou antígeno obtido a partir de ovos de S. mansoni (SEA) a mesma banda foi evidenciada em nove pacientes, desaparecendo em quatro casos, após o tratamento

Genetic population structure and trichothecene genotypes of Fusarium graminearum isolated from wheat in southern Brazil

A sample of 140 Fusarium graminearum isolates from Rio Grande do Sul, Brazil, representing three populations at least 150km from one another, were examined for trichothecene genotype based on PCR amplification of portions of the Tri3 and Tri12 genes and a species-specific (Fg16F/R) primer pair. Genetic diversity was assessed in a sample of 103 F. graminearum lineage 7 (F. graminearum sensu stricto) isolates using amplified fragment length polymorphism (AFLP) markers. The 15-ADON genotype was dominant, followed by the NIV genotype (2-18% prevalence), across all three populations. All NIV-type isolates were in lineage 2 (F. meridionale) and all 15-ADON-type isolates were in lineage 7. Isolates with the same haplotype were rare and genotypic diversity was uniformly high (≥98% of the count), suggesting that recombination has played a significant role. The number of migrants (N m) was estimated between 5 and 6 across all loci and all populations, but the high frequency of private alleles (up to 30%) suggests a historical, rather than contemporary, gene flow. Regarding linkage disequilibrium, 0·8, 1·5 and 2·2% of the locus pairs from the three populations were in disequilibrium, which is lower than values reported in other locations. Thus, Brazilian populations differ from those found in Europe, North America and most of Asia in the presence of a significant frequency (7·8%) of isolates of the NIV genotype in lineage 2. © 2011 The Authors. Plant Pathology © 2011 BSPP.Fil: Astolfi, P.. Universidade Federal do Rio Grande do Sul; BrasilFil: Reynoso, Maria Marta. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; ArgentinaFil: Ramirez, Maria Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Chulze, Sofia Noemi. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Alves, T. C. A.. Universidade Estadual de Maringá; BrasilFil: Tessmann, D. J.. Universidade Estadual de Maringá; BrasilFil: Del Ponte, E. M.. Universidade Federal do Rio Grande do Sul; Brasi

Suprascapular nerve block in shoulder dislocation

Background: The suprascapular nerve is the main sensitive nerve of the shoulder. In 1973, the suprascapular nerve block was applied in the reduction of a series of cases of acute shoulder dislocations using mepivacaine. Barber described a method using anatomic landmarks to locate and block the suprascapular nerve. Methods: This study was approved by our Institutional Review Board and all patients signed an informed consent. We performed a prospective longitudinal study, characterized by a consecutive series of first episode of traumatic shoulder dislocation in patients over 18 years old. From July 2020 to April 2022, 50 cases were included in our study. All patients had their pain evaluated before the blockage, during the reduction and after the reduction. We used the Barber method for the blockage and the Spaso maneuver for reduction. Results: From the 50 cases, 29 were males (58%). The mean age was 58,7 years. 47 cases were anterior dislocations, 2 cases posterior dislocations and one case of luxatio erecta. The mean initial VAS was 7.5 points (minimal 4, maximum 10). The main score during the reduction maneuver was 2 points (0-5) and the main score after reduction was 0,4 (0-3). In only one case, reduction was not successful after 3 attempts, and reduction was performed under sedation. Conclusions: The suprascapular nerve block by Barber’s method proves to be a secure, effective and simple procedure to aid the shoulder dislocation reduction in the emergency room, without the need of any imaging resources