Effect of chitosan and Aloe Vera extract concentrations on the physicochemical properties of chitosan biofilms

Chitosan films have been extensively studied as dressings in formulations for the treatment of chronic wounds. The incorporation of aloe vera (Aloe barbadensis Miller) into chitosan dressings could potentialize the healing process since aloe vera shows several pharmacological activities. This work aimed to evaluate the effect of aloe vera and chitosan concentrations on the physicochemical properties of the developed films. The films were obtained by casting technique and characterized with respect to their color parameters, morphology, barrier and mechanical properties, and thermal analysis. Results showed that the presence of aloe vera modified the films color parameters, changed barrier properties, increased fluid handling capacity (FHC), and decreased water-vapor permeability (WVP). The reduced elongation at break resulted in more rigid films. Aloe vera concentration did not significantly change film properties, but the presence of this gel increased the films stability at temperatures below 200 °C, showing similar behavior as chitosan films above 400 °C. The results suggest a crosslinking/complexation between chitosan and aloe vera, which combine appropriate physicochemical properties for application as wound dressing materials.This work was supported by São Paulo Research Foundation (FAPESP) (2010/17.721-4), Portuguese Science and Technology Foundation (FCT) through the projects M-ERA-NET/0004/2015 (PAIRED) and UIDB/04469/2020 (strategic fund) funded by national funds, and co-financed Education (FCT/MEC) from national funds and FEDER, under the Partnership Agreement PT202info:eu-repo/semantics/publishedVersio

High value-added lignin extracts from sugarcane by-products

This study evaluates the production of lignin bioactive extracts from sugarcane bagasse (SCB) and straw (SCS) alkaline black liquors using greener precipitating agents (methane sulfonic acid (MSA), formic acid (FA) and lactic acid (LA)) as replacers of sulfuric acid (SA), the most common one used in industry. Results showed that the highest precipitation yield was achieved by LA when applied to SCB (14.5 g extract/g SCB). Lignin SCB extracts were similar in composition in terms of total carbohydrates (61–70 %), lignin (22–30 %) and inorganics (1.6–2.6 %). Regarding the SCS extracts, similar yields were obtained among all extracts, however; differences in composition were observed between SA and greener precipitating agents, particularly in terms of sugar content. All extracts exhibited radical scavenging activity; overall the extracts were more effective in the scavenging of ABTS radical. FA was the most promising alternative to SA to recover lignin bioactive extracts. This work suggests organic acids as good candidates for obtaining valuable extracts from alkaline pulping of SCB and SCS instead of the conventional sulfuric acid, thus suggesting a green solution for this biomass valorization.info:eu-repo/semantics/publishedVersio

PROGRAMA DE ESTUDOS PARASITOLÓGICOS NA MICRORREGIÃO DE FEIRA DE SANTANA FAZ EXTENSÃO

Os programas de controle das doenças parasitárias têm sido repensados e quando executados tendo como base as relações com outros problemas de saúde, ambiente físico e participação social, mostram-se mais efetivos e bem sucedidos

A biorefinery from Nannochloropsis sp. microalga – Energy and CO2 emission and economic analyses

Are microalgae a potential energy source for biofuel production? This paper presents the laboratory results from a Nannochloropsis sp. microalga biorefinery for the production of oil, high-value pigments, and biohydrogen (bioH2). The energy consumption and CO2 emissions involved in the whole process (microalgae cultivation, harvest, dewater, mill, extraction and leftover biomass fermentation) were evaluated. An economic evaluation was also performed. Oil was obtained by soxhlet (SE) and supercritical fluid extraction (SFE). The bioH2 was produced by fermentation of the leftover biomass. The oil production pathway by SE shows the lowest value of energy consumption, 177-245 MJ/MJprod, and CO2 emissions, 13–15 kgCO2/MJprod. Despite consuming and emitting c.a. 20% more than the SE pathway, the oil obtained by SFE, proved to be more economically viable, with a cost of 365€/kgoil produced and simultaneously extracting high-value pigments. The bioH2 as co-product may be advantageous in terms of product yield or profit

Avaliação da uniformidade de distribuição de um sistema de irrigação por gotejamento

A produtividade agrícola em áreas irrigadas depende de uma série de fatores, dentre eles, o dimensionamento e manutenção dos sistemas. Em algumas situações, sistema de irrigação com pouco tempo de uso apresentam desuniformidade, comprovando que não apenas o tempo de uso ou a qualidade dos componentes do sistema determina a eficiência na irrigação. Aplicações excessivas ou insuficientes de água prejudicam o desenvolvimento das culturas e, consequentemente, a produtividade e a rentabilidade do agricultor. Este trabalho teve como objetivo avaliar a uniformidade em sistemas de irrigação por gotejamento, utilizados em tomate cultivado no município de Arapiraca-AL. Os coeficientes de uniformidade (CUC, CUD), a eficiência de aplicação, as vazões dos sistemas foram obtidos em avaliações de campo. Os resultados identificaram que o sistema está operando com boa uniformidade e boa eficiência de aplicação.  

Physicochemical properties and interfacial adaptation of root canal sealers.

This study compared the physicochemical properties and interfacial adaptation to canal walls of Endo-CPM-Sealer, Sealapex and Activ GP with the well-established AH Plus sealer. The following analyses were performed: radiopacity, pH variation and solubility using samples of each material and scanning electron microscopy of root-filled bovine incisors to evaluate the interfacial adaptation. Data were analyzed by the parametric and no-parametric tests (α=0.05). All materials were in accordance with the ANSI/ADA requirements for radiopacity. Endo-CPM-Sealer presented the lowest radiopacity values and AH Plus was the most radiopaque sealer (p=0.0001). Except for ActiV GP, which was acidic, all other sealers had basic chemical nature and released hydroxyl ions. Regarding solubility, all materials met the ANSI/ADA recommendations, with no statistically significant difference between the sealers (p=0.0834). AH Plus presented the best adaptation to canal walls in the middle (p=0.0023) and apical (p=0.0012) thirds, while the sealers Activ GP and Endo-CPM-Sealer had poor adaptation to the canal walls. All sealers, except for ActiV GP, were alkaline and all of them fulfilled the ANSI/ADA requirements for radiopacity and solubility. Regarding the interfacial adaptation, AH Plus was superior to the others considering the adaptation to the bovine root canal walls

O uso de recursos naturais pelos artesãos da Aldeia Hippie de Arembepe, Bahia, Brasil

The hippie village of Arembepe is one of the few still existing in the world. Currently this local community is composed by not more than 50 people (children and adults). They look for a new style of life isolated from the great urban centers and encircled by the nature. The art craft is the main economic activity. For the confection of the art craft the community uses the local and external natural local resources. In this study it was possible to identify the intense use of seeds (86.5%). Of the 23 plant resources used by craftsmen of the hippie village, six are locally found: Cocos nucifera L., Crotalaria retusa L., Canavalia rosea (Sw.) DC., Leucaena leucocephala (Lam.) de Wit, Coix lacrima-jobi L., and Canna indica L. The majority of the used seeds (75%) come from other regions of the country, gotten through purchase in specific stores and/or exchange with craftsmen fron other localities. The habit to collecting the seeds and of planting species that supply the necessary seeds for the subsistence of local art craft was observed among the craftsmen of Arembepe village.A aldeia hippie de Arembepe é uma das poucas ainda existentes no mundo. Atualmente, esta comunidade local é composta por cerca de 50 pessoas (crianças e adultos) que buscam outro estilo de vida, isolada dos grandes centros urbanos e rodeada pela natureza. O artesanato é a principal atividade econômica. Para a confecção do artesanato a comunidade usa os recursos naturais locais e externos. Neste estudo foi possível observar o uso intenso de sementes (86,5%). Dos 23 recursos vegetais utilizados pelos artesãos da aldeia hippie, seis estão presentes em Arembepe: Cocos nucifera L., Crotalaria retusa L., Canavalia rosea (Sw.) DC., Leucaena leucocephala (Lam.) de Wit, Coix lacrima-jobi L. e Canna indica L. Cerca de 75% das sementes usadas vem de outras regiões do país, obtidas por meio da compra em lojas específicas e/ou troca com artesãos de outras localidades. Foi constatado entre os artesãos residentes na aldeia hippie de Arembepe o hábito de coletar as sementes em áreas naturais e de plantar espécies que forneçam aquelas necessárias para a subsistência do artesanato local

Biosynthesis of silver nanoparticles mediated by entomopathogenic fungi: antimicrobial resistance, nanopesticides, and toxicity

Silver nanoparticles are widely used in the biomedical and agri-food fields due to their versatility. The use of biological methods for the synthesis of silver nanoparticles has increased considerably due to their feasibility and high biocompatibility. In general, microorganisms have been widely explored for the production of silver nanoparticles for several applications. The objective of this work was to evaluate the use of entomopathogenic fungi for the biological synthesis of silver nanoparticles, in comparison to the use of other filamentous fungi, and the possibility of using these nanoparticles as antimicrobial agents and for the control of insect pests. In addition, the in vitro methods commonly used to assess the toxicity of these materials are discussed. Several species of filamentous fungi are known to have the ability to form silver nanoparticles, but few studies have been conducted on the potential of entomopathogenic fungi to produce these materials. The investigation of the toxicity of silver nanoparticles is usually carried out in vitro through cytotoxicity/genotoxicity analyses, using well-established methodologies, such as MTT and comet assays, respectively. The use of silver nanoparticles obtained through entomopathogenic fungi against insects is mainly focused on mosquitoes that transmit diseases to humans, with satisfactory results regarding mortality estimates. Entomopathogenic fungi can be employed in the synthesis of silver nanoparticles for potential use in insect control, but there is a need to expand studies on toxicity so to enable their use also in insect control in agriculture.The work was funded by the Coordination for the Improvement of Higher Education Personnel (Capes); Sergipe Agricultural Development Company (Emdagro), the Industrial Biotechnology Program, University Tiradentes, Sergipe Technological Park (SergipeTec), and the Banco do Nordeste.info:eu-repo/semantics/publishedVersio

Diversity of metalloproteinases in Bothrops neuwiedi snake venom transcripts: evidences for recombination between different classes of SVMPs

<p>Abstract</p> <p>Background</p> <p>Snake venom metalloproteinases (SVMPs) are widely distributed in snake venoms and are versatile toxins, targeting many important elements involved in hemostasis, such as basement membrane proteins, clotting proteins, platelets, endothelial and inflammatory cells. The functional diversity of SVMPs is in part due to the structural organization of different combinations of catalytic, disintegrin, disintegrin-like and cysteine-rich domains, which categorizes SVMPs in 3 classes of precursor molecules (PI, PII and PIII) further divided in 11 subclasses, 6 of them belonging to PII group. This heterogeneity is currently correlated to genetic accelerated evolution and post-translational modifications.</p> <p>Results</p> <p>Thirty-one SVMP cDNAs were full length cloned from a single specimen of <it>Bothrops neuwiedi </it>snake, sequenced and grouped in eleven distinct sequences and further analyzed by cladistic analysis. Class P-I and class P-III sequences presented the expected tree topology for fibrinolytic and hemorrhagic SVMPs, respectively. In opposition, three distinct segregations were observed for class P-II sequences. P-IIb showed the typical segregation of class P-II SVMPs. However, P-IIa grouped with class P-I cDNAs presenting a 100% identity in the 365 bp at their 5' ends, suggesting post-transcription events for interclass recombination. In addition, catalytic domain of P-IIx sequences segregated with non-hemorrhagic class P-III SVMPs while their disintegrin domain grouped with other class P-II disintegrin domains suggesting independent evolution of catalytic and disintegrin domains. Complementary regions within cDNA sequences were noted and may participate in recombination either at DNA or RNA levels. Proteins predicted by these cDNAs show the main features of the correspondent classes of SVMP, but P-IIb and P-IIx included two additional cysteines cysteines at the C-termini of the disintegrin domains in positions not yet described.</p> <p>Conclusions</p> <p>In <it>B. neuwiedi </it>venom gland, class P-II SVMPs were represented by three different types of transcripts that may have arisen by interclass recombination with P-I and P-III sequences after the divergence of the different classes of SVMPs. Our observations indicate that exon shuffling or post-transcriptional mechanisms may be driving these recombinations generating new functional possibilities for this complex group of snake toxins.</p

Synthesis, Cytotoxicity, and Antileishmanial Activity of N,N'-Disubstituted Ethylenediamine and Imidazolidine Derivatives

This paper describes the preparation of N,N'-disubstituted ethylenediamine and imidazolidine derivatives and their in vitro biological activities against Leishmania species. Of the nine synthesized compounds, five displayed a good activity in both L. amazonensis and L. major promastigotes. The compounds 1,2-Bis(p-methoxybenzyl)ethylenediamine (4) and 1,3-Bis(p-methoxybenzyl)imidazolidines (5) showed the best activity on intracellular amastigotes, with IC50 values of 2.0 and 9.4 μ/mL, respectively. In addition, none of compounds were cytotoxic against mammalian cells. The leishmanicidal activity can be related with inhibition of polyamine synthesis and cellular penetration within biological membranes