Nisin

Antimicrobial peptides (AMPs) are small cationic peptides which protect their hosts against bacteria, protozoa, viruses, and fungi. Bacterial AMPs are called bacteriocins, and are produced by both Gram-positive and Gram-negative bacteria. Because of their high potency and specificity, bacteriocins are considered as promising antimicrobial agents for different applications, including food preservation and infection treatment; specially the ones produced by acid lactic bacteria species (Gram-positive). Nisin is the most intensively studied and used bacteriocin, it is found commercially available and its use is regulated in over 50 countries. Therefore, special attention is given to this bacteriocin

The influence of pH, polyethylene glycol and polyacrylic acid on the stability of stem bromelain

Enzyme stability is critical in biotechnology, pharmaceutical and cosmetic industries. Investigations on this subject have drawn attention because of its practical application. Bromelain is a thiol-endopeptidase, obtained from pineapple (Ananas comosus), known for its clinical and therapeutic applications, particularly to selective burn debridement and improvement of antibiotic action and anti-inflammatory activities. To date, the use of bromelain in pharmacological or industrial applications is limited, due to commercial availability, costs, and sensitivity to pH and temperature. Therefore, a better understanding of enzyme stability would be of great interest. The aim of this study was to evaluate bromelain activity and stability in several pH (2.0 to 8.0) and in polyethylene glycol and polyacrylic acid solutions. We observed that bromelain was able to maintain its stability at pH 5.0 for the temperatures studied. PEG solutions increased bromelain stability, but PAA solutions had the opposite effect.Estabilidade de enzimas é uma questão fundamental em indústrias biotecnológicas, farmacêuticas e cosméticas. As investigações sobre o assunto têm chamado a atenção por sua aplicação prática. A bromelina é uma tiol-endopeptidase, obtida a partir do abacaxi (Ananas comosus). É conhecida por suas aplicações clínicas e terapêuticas, especialmente para desbridamento seletivo de queimaduras, melhoria de ações antibiótica e de atividades anti-inflamatórias. Até o momento, a utilização da bromelina em aplicações farmacológicas industriais é limitada, devido à disponibilidade comercial, os custos, a sensibilidade ao pH e temperatura. Portanto, a maior compreensão da estabilidade desta enzima seria de grande interesse. O objetivo deste estudo foi avaliar a estabilidade da atividade da bromelina em vários pH (2,0 a 8,0) e em soluções de polietilenoglicol e de ácido poliacrílico. Observamos que a bromelina foi capaz de manter a sua estabilidade em pH 5.0, em todas as temperaturas estudadas. Soluções de PEG aumentaram a estabilidade da bromelina, enquanto que soluções de PAA obtiveram efeito oposto

Bem-estar animal em laboratório: enriquecimento ambiental apresenta efeito positivo na experimentação animal

Reproductive and developmental toxicology has focused on the need to approach the effects of organism exposure to various drugs during pregnancy after the mid-50’s, when the thalidomide tragedy stroke humanity. In recent decades, this area of study has developed a lot due to animal testing, raising awareness on the need to improve the quality of life of such animals. Therefore, this paper aims to investigate how the science of animal welfare can improve scientific research as a whole, including the reproductive and developmental toxicology fields, by emphasizing environmental enrichment in animal facilities. To do so, we conducted an integrative literature review on several quantitative and qualitative methodological approaches that are applicable to toxicology studies. Here, we present evidence that environmental enrichment improves animal welfare and prevents or reduces the negative effects of captive housing, which must be a principle of toxicological research for ethical, legal and scientific reasons.Na toxicologia da reprodução e do desenvolvimento, a atenção necessária foi dada aos efeitos da exposição do organismo às inúmeras drogas durante o período gestacional somente após a metade dos anos 50, quando a tragédia da talidomida atingiu a humanidade. Assim, esta área alcançou desenvolvimento científico com a contribuição da experimentação animal nas últimas décadas. O uso de animais de laboratórios para a pesquisa científica expôs a necessidade de melhorar a qualidade de vida destas espécies. Portanto, este trabalho tem como objetivo investigar como a ciência do bem-estar animal pode melhorar a pesquisa científica como um todo, incluindo na área de toxicologia da reprodução e de desenvolvimento, enfatizando o enriquecimento ambiental em biotérios. Uma revisão integrativa de literatura foi realizada, incluindo abordagens quantitativas e qualitativas, quais podem ser aplicadas para estudos de toxicologia. Aqui, são mostradas evidências de que o enriquecimento ambiental melhora o bem-estar animal e previne ou reduz os efeitos negativos do cativeiro, qual deve um princípio da pesquisa toxicológica por razões éticas, argumentos legais e garantias científicas

Aquecimento ôhmico: novos desafios no tratamento térmico de materiais

[Excerto] Introdução: O tratamento térmico de materiais encontra-se dentre os processos mais utilizados industrialmente. Na indústria de alimentos, por exemplo, o tratamento térmico (por possuir ação letal sobre microorganismos) é o principal procedimento físico de que a tecnologia de alimentos dispõe para aumentar a vida útil dos alimentos (Ordóñez et al., 2005). Desta forma, novos métodos de aquecimento que acarretem em baixo gasto energético ou em maior eficiência energética continuam a atrair interesse Palaniappan e Sastry, 1992). Dentre as tecnologias de aquecimento emergentes, o aquecimento ôhmico apresenta-se bastante promissor. [...]info:eu-repo/semantics/publishedVersio

Antimicrobial effectiveness of silver nanoparticles co-stabilized by the bioactive copolymer pluronic F68

Abstract\ud \ud \ud \ud Background\ud \ud Silver nanoparticles (AgNps) have attracted much interest in biomedical engineering, since they have excellent antimicrobial properties. Therefore, AgNps have often been considered for incorporation into medical products for skin pathologies to reduce the risk of contamination. This study aims at evaluating the antimicrobial effectiveness of AgNps stabilized by pluronic™ F68 associated with other polymers such as polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP).\ud \ud \ud \ud Methods\ud \ud AgNps antimicrobial activity was evaluated using the minimum inhibitory concentration (MIC) method. The action spectrum was evaluated for different polymers associated with pluronic™ F68 against the gram negative bacteria P. aeuroginosa and E. coli and the gram positive bacteria S. Aureus.\ud \ud \ud \ud Results\ud \ud AgNps stabilized with PVP or PVA and co-stabilized with pluronic™ F68 are effective against E. coli and P. aeruginosa microorganisms, with MIC values as low as 0.78% of the concentration of the original AgNps dispersion. The antimicrobial action against S. aureus is poor, with MIC values not lower than 25%.\ud \ud \ud \ud Conclusions\ud \ud AgNps stabilized by different polymeric systems have shown improved antimicrobial activity against gram-negative microorganisms in comparison to unstabilized AgNps. Co-stabilization with the bioactive copolymer pluronic™ F68 has further enhanced the antimicrobial effectiveness against both microorganisms. A poor effectiveness has been found against the gram-positive S. aureus microorganism. Future assays are being delineated targeting possible therapeutic applications.This research was supported by grants from FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil), CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil) and CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil)

Effect of polysaccharide sources on the physicochemical properties of bromelainchitosan nanoparticles

Bromelain, a set of proteolytic enzymes potential pharmaceutical applications, was encapsulated in chitosan nanoparticles to enhance enzyme stability, and the effect of different chitosan sources was evaluated. Chitosan types (i.e., low molecular weight chitosan, chitosan oligosaccharide lactate, and chitosan from shrimp shells) produced nanoparticles with different physicochemical properties, however in all cases, particle size and zeta potential decreased, and polydispersity index increased after bromelain addition. Bromelain encapsulation was higher than 84% and 79% for protein content and enzymatic activity, respectively, with low molecular weight chitosan presenting the highest encapsulation efficiency. Nanoparticle suspension was also tested for accelerated stability and rheological behavior. For the chitosan–bromelain nanoparticles, an instability index below 0.3 was recorded and, in general, the loading of bromelain in chitosan nanoparticles decreased the cohesiveness of the final suspension.This research was granted by FAPESP (2016/03444-5,2017/05275-9,and2017/05333-9), CNPq and FAEPEX, and by the Portuguese Science and Technology Foundation, Ministry of Science and Education (FCT/MEC) through national funds, and co-financed by FEDER, under the project reference M-ERA-NET/0004/2015 (PAIRED) Partnership Agreement PT2020.info:eu-repo/semantics/publishedVersio

Bacterial nanocellulose and fibroin: natural products to produce a structure membranes

Fibroin (FB) and bacterial nanocellulose (BC) are natural products, being used in biomedicine, electronics, food industries and other areas. Both show biocompatibility, able to be used for many different purposes. The blending of fibroin and bacterial nanocellulose was design to produce a biocompatible material to be applied with a medical device. For this reason, the objective of this work was to evaluate the structure properties of the blending of BC and FB. Thus, FB was extracted from Bombyx mori and BC was produced by fermentation process utilizing Gluconacetobacter xylinus. The membranes composed of BC-FB were produced by immersion contact for 24 hours, at 25°C, in 100rpm; without crosslinking agent. After the production the membrane samples were dried and characterized by Fourier transform infrared spectroscopy (FTIR spectroscopy), mechanical proprieties, swelling efficiency, scanning electron microscopy (SEM) and computerized microtomography (µCt). Results indicate that the hydrogen-bonded porous membranes obtained displayed anisiotropic, closed and interconnected porous morphology. The morphometric characteristics, which resemble a honeycomb and consist of a long structure with high connectivity and high total porosity, amplify the areas of BC-FB blend applications, with potential utilization with optoelectronic devices, in areas ranging from environmental to tissue engineering. Furthermore, the production by immersion contact will allow the upscale process and the development of green label material.Keywords: Polymers conjugation, Membranes; Fibroin; Bacterial nanocellulose

Flavonoid-enriched plant-extract-loaded emulsion: a novel phytocosmetic sunscreen formulation with antioxidant properties

The aim of this study was to develop a phytocosmetic sunscreen emulsion with antioxidant effect, containing a blend of flavonoid-enriched plant extracts. In vitro sun protection factor, antioxidant activity, skin irritation, photostability, cutaneous permeation, and retention of flavonoids were evaluated. Thermodynamically stable emulsions were obtained and tested for sensorial analysis after loading the blend of extracts. The selected emulsion was stable when stored at low temperatures (5 C), for which after 120 days the concentration of quercetin and rutin were above their limit of quantification, i.e., 2.8 ± 0.39 µg/mL and 30.39 ± 0.39 µg/mL, respectively. Spreadability, low rupture strength and adhesiveness were shown to be similar to a conventional topical product. Higher brittleness, pseudo-plastic, and viscoelastic behaviors were also recorded for the developed phytocosmetic sunscreen. The product presented a critical wavelength of 387.0 nm and ultraviolet rays A and B (UVA/UVB) rate of 0.78, confirming that the developed formulation shows capacity for UVA/UVB protection, protecting skin against damages caused by Ultraviolet (UV) radiation. Rutin was shown to permeate the skin barrier and was also quantified in the stratum corneum (3.27 ± 1.92 µg/mL) by tape stripping and retention test (114.68 ± 8.70 µg/mL). The developed flavonoid-enriched phytocosmetic was shown to be non-irritant to skin by an in vitro assay. Our results confirm the antioxidant activity, sun protection, and physical properties of the developed phytocosmetic for topical application.This research was funded by FAPESP (grant number 2015/25533‐7 and 2017/14757‐7), CAPES and CNPq. The authors also received support from the Portuguese Science and Technology Foundation (FCT/MCT) and from European Funds (PRODER/COMPETE) under the project reference M‐ERA‐NET/0004/2015‐PAIRED, co‐financed by FEDER, under the Partnership Agreement PT2020, and PhD scholarship (SFRH/BD/130555/2017).info:eu-repo/semantics/publishedVersio

Bacterial cellulose production by Gluconacetobacter xylinus by employing alternative culture media

Bacterial cellulose (BC) is used in different fields as a biological material due to its unique properties. Despite there being many BC applications, there still remain many problems associated with bioprocess technology, such as increasing productivity and decreasing production cost. New technologies that use waste from the food industry as raw materials for culture media promote economic advantages because they reduce environmental pollution and stimulate new research for science sustainability. For this reason, BC production requires optimized conditions to increase its application. The main objective of this study was to evaluate BC production by Gluconacetobacter xylinus using industry waste, namely, rotten fruits and milk whey, as culture media. Furthermore, the structure of BC produced at different conditions was also determined. The culture media employed in this study were composed of rotten fruit collected from the disposal of free markets, milk whey from a local industrial disposal, and their combination, and Hestrin and Schramm media was used as standard culture media. Although all culture media studied produced BC, the highest BC yield60 mg/mLwas achieved with the rotten fruit culture. Thus, the results showed that rotten fruit can be used for BC production. This culture media can be considered as a profitable alternative to generate high-value products. In addition, it combines environmental concern with sustainable processes that can promote also the reduction of production cost.The authors would like to acknowledge the Brazil National Council of Technological and Scientific Development (CNPq, FAPESP, and CAPES), the financial support from FAPESP 2009/14897-7, and Fundacao para a Ciencia e a Tecnologia (FCT)/Portugal through the project PTDC/EBB-EBI/112170/2009 for the financial support and scholarship. Special thanks to Talita Almeida Vicentin for technical support