Influence of Immobilization Strategies on the Antibacterial Properties of Antimicrobial Peptide-Chitosan Coatings

It is key to fight bacterial adhesion to prevent biofilm establishment on biomaterials. Surface immobilization of antimicrobial peptides (AMP) is a promising strategy to avoid bacterial colonization. This work aimed to investigate whether the direct surface immobilization of Dhvar5, an AMP with head-to-tail amphipathicity, would improve the antimicrobial activity of chitosan ultrathin coatings. The peptide was grafted by copper-catalyzed azide-alkyne cycloaddition (CuAAC) chemistry by either its C- or N- terminus to assess the influence of peptide orientation on surface properties and antimicrobial activity. These features were compared with those of coatings fabricated using previously described Dhvar5-chitosan conjugates (immobilized in bulk). The peptide was chemoselectively immobilized onto the coating by both termini. Moreover, the covalent immobilization of Dhvar5 by either terminus enhanced the antimicrobial effect of the chitosan coating by decreasing colonization by both Gram-positive (Staphylococcus aureus, Staphylococcus epidermidis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. Relevantly, the antimicrobial performance of the surface on Gram-positive bacteria depended on how Dhvar5-chitosan coatings were produced. An antiadhesive effect was observed when the peptide was grafted onto prefabricated chitosan coatings (film), and a bactericidal effect was exhibited when coatings were prepared from Dhvar5-chitosan conjugates (bulk). This antiadhesive effect was not due to changes in surface wettability or protein adsorption but rather depended on variations in peptide concentration, exposure, and surface roughness. Results reported in this study show that the antibacterial potency and effect of immobilized AMP vary greatly with the immobilization procedure. Overall, independently of the fabrication protocol and mechanism of action, Dhvar5-chitosan coatings are a promising strategy for the development of antimicrobial medical devices, either as an antiadhesive or contact-killing surface.This work was financed by the FCT- Fundação para a Ciência e a Tecnologia through projects POCI-01-0145-FEDER-031781 (AntINFECT), UIB/50006/2020 (LAQV-REQUIMTE) and FEDER—Fundo Europeu de Desenvolvimento Regional through NORTE 2020—Programa Operacional Regional do Norte-Bio2Skin Advanced (NORTE-01-0247-FEDER-047225). M Barbosa (SFRH/BD/108966/2015) and Pedro Alves (SFRH/BD/145471/2019) Ph.D. grants were financially supported by national (FCT/Norte 2020 Framework) and European Union funds (ESF—European Social Fund). Paula Parreira (CEECIND/01210/2018) and Maria Cristina L. Martins (LA/P/0070/2020) also thank FCT for funding. Maria Cristina L. Martins also acknowledges the MOBILIsE Project, which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement no. 951723

Biogeochemical Controls of CO2 Concentrations and Fluxes in an Amazon Floodplain Lake – a Multiscale Approach

Purpose. Roles and obstacles to parent involvement at the site level are identified. Methods and strategies for developing parent involvement programs are investigated. Parent, teacher and administrator group perceptions are described and compared. Methodology. Descriptive and comparative surveys address role expectations, potential obstacles, and current parent involvement trends. Parent, teacher, and administrative group responses at Lathrop School are analyzed using mean ranks and median scores for each group. School records for parent involvement activities are examined. Findings. Of the 28 items addressing parent involvement role expectations, eight decision-making, two Parents as Teachers, and one Parents as Learners items show statistically significant differences in group perspectives for role expectations. Of the 31 items analyzing obstacles, group perceptions are different in four areas. Two items show a statistically significant difference among group beliefs in the area of school attitudes. Identification of current parent involvement trends indicate that parents are involved most frequently as Teachers and least frequently as Decision Makers. Recommendations. Lathrop School can use the study to develop clear role expectation guidelines. Suggestions are made for establishing role expectations for all four categories of parent involvement. Recommendations are given for addressing cultural obstacles and suggestions are made for further research and implementation of a more effective parent involvement program

Infochemical-tritrophic Interactions of Soybean Aphids-host Plants-natural Enemies and Their Practical Applications in Pest Management

The soybean aphid, Aphis glycines Matsumura, is a newly invasive insect species that seriously threatens U.S. soybean production. This aphid pest has kept haunting many soybean growers by developing large colonies on soybeans in North America since 2000. Since its first appearance inWisconsin, it has spread to over half of US states and southern provinces in Canada. The heavy infestation of this pest whittles soybean growers’ profits and causes hundreds of million dollar losses. The present chapter will mainly describe efforts in studying aphid chemical ecology and sensory physiology for understanding how male aphids find their mates and host plants. It will also cover research efforts to understand host plant associated volatiles being used as cues for overwintering host plant location. In addition, findings on how soybean plant defensive system works against aphid infestation, as well as how those induced plant volatiles are used by aphid’s natural enemies for prey location will be presented. Finally, the use the basic understandings for developing useful tools for soybean aphid practical control will be discussed

The long-term outcome of impulsive compulsive behaviours in Parkinson's disease

Introduction: Impulsive compulsive behaviours (ICBs) such as dopamine dysregulation syndrome (DDS), pathological gambling, compulsive sexual behaviour, punding, compulsive shopping and binge eating are recognised complications of dopaminergic treatment that affect at least one in seven patients with Parkinson’s disease (PD). Only a few studies provide long-term data on ICBs although any firm conclusions are limited by restricted follow-up periods. We present long-term longitudinal data on 46 PD patients with ICBs with follow-up for a mean period of 8.2 years. / Methods: Patients with PD and ICBs who participated in previous research studies from 2007 to 2012 visit 1 (V1) were invited for re-assessment visit 2 (V2). Participants underwent a clinical interview and assessment with questionnaires and scales (detailed in online supplementary materials). The diagnosis of ICBs was based on screening questionnaires and confirmed with a structured interview. The study received ethics approval. Data was analysed in Statistical Package for Social Science 22 (SPSS 22). All variables were tested for normality and statistical tests chosen accordingly. A p value<0.05 was considered significant. Bonferroni correction was applied for comparison between visits and significance was considered to have been reached when p<0.025. / Results: Of the 90 original participants, 46 were included. Eight declined to participate, five were lost to follow-up and 31 had died (see online supplementary figure 1). No cases of suicide or traumatic fatality were reported. Participants were followed up for 8.2 years (±2.6). Three patients had a biallelic parkin mutation. See table 1 for demographic and clinical details at each visit and online supplementary table 1 for results of the scales/questionnaires used at V2

Jogo educativo sobre drogas para cegos: construção e avaliação

Estudo realizado com o objetivo de construir e avaliar um jogo educativo sobre drogas psicoativas acessível a pessoas cegas, desenvolvido em três etapas: construção do jogo educativo, avaliação por três especialistas em educação especial e doze cegos. Foi construído um jogo de tabuleiro denominado Drogas: jogando limpo . Na Versão Alfa os especialistas fizeram sugestões em relação às e instruções e ao tabuleiro: textura das casas, peças do jogo e escrita em Braille. Na Versão Beta, procedeu-se à avaliação pelos cegos, os quais sugeriram alterações na textura das casas e colocação de velcro para fixação do pino no tabuleiro. Passou-se, então, à Versão Gama, jogada pelas últimas três duplas de cegos e considerada adequada. Na avaliação dos juízes, o jogo revelou-se adequado, pois permite o acesso à informação sobre drogas psicoativas de maneira lúdica