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1.
Food Chem ; 410: 135319, 2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-36634564

RESUMO

The tomato processing industry is one of the world's most important markets. This industry aims to optimise production, minimise energy costs and waste streams while ensuring high-quality products. This sector produces substantial amounts of by-products frequently disposed of as waste rather than reintroducing them with a new intent into the supply chain. However, these by-products are rich in bioactive compounds (BC), including carotenoids, fibre, which exhibit antioxidant, anti-inflammatory and chemopreventive properties, and cardiovascular protection. Reusing these compounds is favourable to reducing the environmental impact and enables the development of added-value products with various possible uses such as food and feed additives, nutraceuticals, cosmeceuticals, etc. This review summarises relevant issues towards the recovery and valorisation of BC from industrial tomato by-products within a circular economy context.


Assuntos
Solanum lycopersicum , Humanos , Carotenoides/análise , Antioxidantes , Manipulação de Alimentos , Suplementos Nutricionais
2.
Placenta ; 97: 95-100, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32792071

RESUMO

Preeclampsia is the archetype of a spectrum of clinical disorders related to abnormal placental development or function, characterized by placental histological lesions. Among those lesions, decidual vasculopathy is a term used to describe lesions of maternal spiral arteries, which are encountered on placental examination in about half of the women with preeclampsia. The morphological features of the lesions include perivascular lymphocytic infiltration, fibrinoid necrosis and foam cell incorporation within the vessel wall. Due to the resemblance of the latter characteristic to atherosclerosis, they are alternatively termed acute atherosis. Decidual vasculopathy correlates with worse maternal and neonatal outcomes, as well as placental pathology. In this article, we review the available literature on decidual vasculopathy and address the pitfalls in histological analysis of the lesions, including the varying definitions of the lesions and sample collection methods. We also discuss the current evidence on the etiology of the lesions and propose a novel hypothesis linking the three etiological pathways to the formation of decidual vasculopathy and, ultimately, the emergence of the heterogeneous group of placental dysfunction disorders, known as the great obstetric syndromes.


Assuntos
Decídua/irrigação sanguínea , Pré-Eclâmpsia/patologia , Doenças Vasculares/patologia , Remodelação Vascular/fisiologia , Artérias/patologia , Decídua/patologia , Feminino , Humanos , Gravidez
3.
Mol Plant ; 12(6): 784-803, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-30953788

RESUMO

The root system is a major determinant of a plant's access to water and nutrients. The architecture of the root system to a large extent depends on the repeated formation of new lateral roots. In this review, we discuss lateral root development from a systems biology perspective. We focus on studies combining experiments with computational modeling that have advanced our understanding of how the auxin-centered regulatory modules involved in different stages of lateral root development exert their specific functions. Moreover, we discuss how these regulatory networks may enable robust transitions from one developmental stage to the next, a subject that thus far has received limited attention. In addition, we analyze how environmental factors impinge on these modules, and the different manners in which these environmental signals are being integrated to enable coordinated developmental decision making. Finally, we provide some suggestions for extending current models of lateral root development to incorporate multiple processes and stages. Only through more comprehensive models we can fully elucidate the cooperative effects of multiple processes on later root formation, and how one stage drives the transition to the next.


Assuntos
Raízes de Plantas/metabolismo , Biologia de Sistemas/métodos , Arabidopsis/metabolismo , Arabidopsis/fisiologia , Regulação da Expressão Gênica de Plantas , Raízes de Plantas/fisiologia
4.
Carbohydr Polym ; 201: 31-38, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30241824

RESUMO

An integrated process enabling the simultaneous production and purification of fructo-oligosaccharides (FOS) was explored. A co-culture fermentation with Aspergillus ibericus (used as FOS producer strain) and Saccharomyces cerevisiae YIL162 W (for small saccharides removal) was optimized. Inoculation conditions of S. cerevisiae, fermentative broth composition, temperature and pH were optimized by experimental design. Yeast extract concentration and temperature were the most significant variables affecting FOS purity. Co-culture fermentations with simultaneously inoculation of the strains, run under 30 °C, initial pH 6.0 and 17 g L-1 yeast extract led to FOS mixtures with 97.4 ± 0.2% (w/w) purity. The fermentations conducted in bioreactor, at a 0.8 vvm aeration rate, yielded 0.70 ± 0.00 gFOS.ginitial GF-1 at 45 h fermentation, with a FOS content of 133.7 ± 0.1 g L-1. A purity of FOS up to 93.8 ± 0.7% (w/w) was achieved. The one-step fermentation proved to be efficient, economical and fast.

6.
Carbohydr Polym ; 136: 274-81, 2016 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-26572356

RESUMO

Fructo-oligosaccharides (FOS) obtained by fermentation of sucrose may be purified at large-scale by continuous chromatography (Simulated Moving Bed: SMB). In order to improve the efficiency of the subsequent SMB purification, the optimization of the fermentative broth composition in salts and sugars was investigated. Fermentations conducted at reduced amount of salts, using Aureobasidium pullulans whole cells, yielded 0.63 ± 0.03 g of FOS per gram of initial sucrose. Additionally, a microbial treatment was proposed to reduce the amount of small saccharides in the mixture. Two approaches were evaluated, namely a co-culture of A. pullulans with Saccharomyces cerevisiae; and a two-step fermentation in which FOS were first synthesized by A. pullulans and then the small saccharides were metabolized by S. cerevisiae. Assays were performed in 100mL shaken flasks and further scaled-up to a 3 L working volume bioreactor. Fermentations in two-step were found to be more efficient than the co-culture ones. FOS were obtained with a purity of 81.6 ± 0.8% (w/w), on a dry weight basis, after the second-step fermentation with S. cerevisiae. The sucrose amount was reduced from 13.5 to 5.4% in total sugars, which suggests that FOS from this culture broth will be more efficiently separated by SMB.


Assuntos
Ascomicetos/metabolismo , Biotecnologia/métodos , Fermentação , Frutose/química , Oligossacarídeos/biossíntese , Oligossacarídeos/química , Saccharomyces cerevisiae/metabolismo , Ascomicetos/citologia , Técnicas de Cocultura , Saccharomyces cerevisiae/citologia
7.
J Food Sci Technol ; 52(12): 8292-9, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26604406

RESUMO

In this work five sources of galactomannans, Adenanthera pavonina, Cyamopsis tetragonolobus, Caesalpinia pulcherrima, Ceratonia siliqua and Sophora japonica, presenting mannose/galactose ratios of 1.3, 1.7, 2.9, 3.4 and 5.6, respectively, were used to produce galactomannan-based films. These films were characterized in terms of: water vapour, oxygen and carbon dioxide permeabilities (WVP, O 2 P and CO 2 P); moisture content, water solubility, contact angle, elongation-at-break (EB), tensile strength (TS) and glass transition temperature (T g ). Results showed that films properties vary according to the galactomannan source (different galactose distribution) and their mannose/galactose ratio. Water affinity of mannan and galactose chains and the intermolecular interactions of mannose backbone should also be considered being factors that affect films' properties. This work has shown that knowing mannose/galactose ratio of galactomannans is possible to foresee galactomannan-based edible films properties.

8.
Transplant Proc ; 47(4): 985-8, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-26036500

RESUMO

INTRODUCTION: Cardiovascular disease is more common in renal transplant recipients (RTRs) than in the general population, and is the major cause of both graft loss and patient death in RTRs. OBJECTIVES: This study aimed to characterize the cardiovascular risk factors, calculate the 7-year risk for major adverse cardiac events and the 7-year risk for death in a population of RTRs using a cardiovascular risk calculator, and determine the main cardiovascular risk factors associated with increased prediction of major adverse cardiac event (MACE) and death. PATIENTS: This is a retrospective review of clinical data from 121 RTRs who are in follow-up programs at our institution, and who had a functioning and stable graft for longer than 6 months. RESULTS: Among 121 adult patients followed at our institution (59.5% males, mean age of 49.6 ± 13.8 years, mean times for functioning grafts were 105 ± 73.5 mo), 86.8% had hypertension, 19.8% had diabetes, 24.8% were current or former smokers, 61.9% had increased body mass index, and 71% had dyslipidemia. The 7-year risk for MACE was more than 10% in 38 (31.4%) patients with age, diabetes, and smoke being independent risk predictors. The 7-year risk for death was more than 10% in 56 (46.3%) patients with age, diabetes, blood pressure, smoking, and male gender being independent risk predictors. CONCLUSION: There is a high prevalence of cardiovascular risk factors in a population of RTRs, and there is increased risk for MACE and death. Accurate risk prediction is important for physician decision support and patient education, promoting improved cardiovascular health of RTRs, and thus prolonging the survival of both patients and graft.


Assuntos
Doenças Cardiovasculares/epidemiologia , Dislipidemias/epidemiologia , Transplante de Rim/efeitos adversos , Metaboloma/fisiologia , Transplantados , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/metabolismo , Causas de Morte/tendências , Dislipidemias/etiologia , Dislipidemias/metabolismo , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Portugal/epidemiologia , Prevalência , Estudos Retrospectivos , Fatores de Risco
9.
Biomed Res Int ; 2013: 961842, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23691515

RESUMO

The capability of a cell bound biosurfactant produced by Lactobacillus pentosus, to accelerate the bioremediation of a hydrocarbon-contaminated soil, was compared with a synthetic anionic surfactant (sodium dodecyl sulphate SDS-). The biosurfactant produced by the bacteria was analyzed by Fourier transform infrared spectroscopy (FTIR) that clearly indicates the presence of OH and NH groups, C=O stretching of carbonyl groups and NH nebding (peptide linkage), as well as CH2-CH3 and C-O stretching, with similar FTIR spectra than other biosurfactants obtained from lactic acid bacteria. After the characterization of biosurfactant by FTIR, soil contaminated with 7,000 mg Kg(-1) of octane was treated with biosurfactant from L. pentosus or SDS. Treatment of soil for 15 days with the biosurfactant produced by L. pentosus led to a 65.1% reduction in the hydrocarbon concentration, whereas SDS reduced the octane concentration to 37.2% compared with a 2.2% reduction in the soil contaminated with octane in absence of biosurfactant used as control. Besides, after 30 days of incubation soil with SDS or biosurfactant gave percentages of bioremediation around 90% in both cases. Thus, it can be concluded that biosurfactant produced by L. pentosus accelerates the bioremediation of octane-contaminated soil by improving the solubilisation of octane in the water phase of soil, achieving even better results than those reached with SDS after 15-day treatment.


Assuntos
Hidrocarbonetos/metabolismo , Lactobacillus/metabolismo , Dodecilsulfato de Sódio/farmacologia , Poluentes do Solo/metabolismo , Tensoativos/farmacologia , Biodegradação Ambiental/efeitos dos fármacos , Emulsões , Cinética , Lactobacillus/efeitos dos fármacos , Octanos/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier
10.
J Appl Microbiol ; 115(1): 114-24, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23581645

RESUMO

AIMS: In this study, a gene that encodes a carboxylesterase (carb) in Penicillium expansum GF was cloned, sequenced and overexpressed by Penicillium griseoroseum PG63, and the enzyme was characterized. METHODS AND RESULTS: The recombinant strain, P. griseoroseum T55, obtained upon transformation using the plasmid pAN-52-1-carb, showed integration of the carb gene into at least two heterologous sites of the genome by Southern blotting. Furthermore, the recombinant strain T55 exhibited almost a fourfold increase in carboxylesterase activity compared with PG63 strain when both were cultured without inducers. Based on the secondary structure and multiple sequence alignments with carboxylesterases, cholinesterase and lipase, a three-dimensional model was obtained. The α/ß barrel topology, that is typical of esterases and lipases, was indicated for the CARB protein with Ser(213)-Glu(341)-His(456) as the putative catalytic triad. CARB preferentially hydrolysed acyl chains with eight carbon atoms, and its activity was optimal at a pH of 7·0 and a temperature of 25°C. CARB exhibited stability in alkaline pH, high activity under mesophilic conditions and stability in organic solvents. CONCLUSION: The CARB protein is potentially useful in bioremediation, food and chemical/pharmaceutical industries. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first to report the development of a recombinant strain superproducing a Penicillium sp. carboxylesterase.


Assuntos
Carboxilesterase/química , Carboxilesterase/metabolismo , Penicillium/enzimologia , Sequência de Aminoácidos , Sequência de Bases , Carboxilesterase/genética , Clonagem Molecular , Dados de Sequência Molecular , Penicillium/genética , Penicillium/metabolismo , Alinhamento de Sequência
11.
Food Chem ; 138(2-3): 1510-4, 2013 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-23411274

RESUMO

Corn cobs, grape skins and grape stems were evaluated as support materials for immobilization of the lactic acid bacteria Oenococcus oeni. The support materials with immobilized cells were further used in malolactic fermentation (MLF) of white wine. Viability of using the immobilized supports was evaluated in consecutive batch fermentations under different conditions of temperature, ethanol and SO(2). Additionally, the possibility of storage and operational stability of the immobilized supports was also studied. All the three supports presented large potential for immobilization of O. oeni cells. The consecutive batches of MLF were successfully conducted for a total period of around 5 months with the possibility of storage of the biocatalyst for 30 d in wine at 25°C.


Assuntos
Microbiologia Industrial/instrumentação , Ácido Láctico/metabolismo , Malatos/metabolismo , Oenococcus/metabolismo , Vinho/microbiologia , Células Imobilizadas/química , Células Imobilizadas/metabolismo , Fermentação , Microbiologia Industrial/métodos , Oenococcus/química , Vinho/análise
12.
Inflammopharmacology ; 20(6): 315-22, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22271003

RESUMO

OBJECTIVE: The present work reports the purification and partial characterization of an antibacterial lectin (EmaL) obtained from Eugenia malaccensis seeds as well as the evaluation of its effect in the daily topical treatment of repairing process of cutaneous wounds in mice. MATERIALS AND METHODS: The cutaneous wound was produced by the incision of the skin and use of lectin in the treatment of mice cutaneous wounds was evaluated. Surgical wounds were treated daily with a topical administration of EmaL and parameters such as edema, hyperemia, scab, granulation and scar tissues as well as contraction of wounds were analyzed. RESULTS: A novel lectin, with a molecular mass of 14 kDa, was isolated from E. malaccensis using affinity chromatography. The lectin (EmaL) agglutinated glutaraldehyde-treated rabbit and human erythrocytes; the lectin-induced rabbit erythrocyte agglutination was inhibited by glucose, casein, ovalbumin and fetuin. Also, Emal was very effective in the inhibition of bacterial growth, with the best inhibition results obtained for Staphylococcus aureus. Inflammatory signals such as edema and hyperemia were statistically less intense when EmaL was applied compared to the control. The histopathological analysis showed that the treated injured tissue presented reepithelialization (complete or partial) and areas of transition more evidenced than those of the control group, especially due to well organized pattern of collagen fibers presented in the granulation fibrous tissue. CONCLUSION: Presented results are a preliminary indication of the pharmacological interest in using EmaL as antimicrobial agent and in the repairing process of cutaneous wounds.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Lectinas/química , Lectinas/farmacologia , Pele/efeitos dos fármacos , Syzygium/química , Cicatrização/efeitos dos fármacos , Administração Cutânea , Animais , Antibacterianos/isolamento & purificação , Eritrócitos/efeitos dos fármacos , Feminino , Tecido de Granulação/efeitos dos fármacos , Humanos , Lectinas/isolamento & purificação , Camundongos , Coelhos , Sementes/química , Staphylococcus aureus/efeitos dos fármacos
13.
N Biotechnol ; 29(3): 395-401, 2012 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-22100432

RESUMO

In this study, a simple and efficient process to purify fructo-oligosaccharides (FOS) from a fermentative broth was proposed using a single activated charcoal column. The FOS adsorption onto the activated charcoal was modeled by a pseudo-second order model. Several volumes and concentrations of water/ethanol were studied to optimize the selective desorption of sugars from the broth mixture at 25°C. Mixtures containing 50.6% (w/w) of FOS (FOS content in the fermentative broth) were purified to 92.9% (w/w) with a FOS recovery of 74.5% (w/w). Moreover, with the proposed process, fractions with purity up to 97% (w/w) of FOS were obtained. This purification process was also found to be efficient in the desalting of the fermentative broth.


Assuntos
Carvão Vegetal/química , Meios de Cultura/química , Frutose/isolamento & purificação , Oligossacarídeos/isolamento & purificação , Saccharomycetales/crescimento & desenvolvimento , Adsorção , Frutose/biossíntese , Oligossacarídeos/biossíntese , Saccharomycetales/metabolismo
14.
J Appl Microbiol ; 111(4): 818-25, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21726361

RESUMO

AIMS: To obtain recombinant strains of Penicillium griseoroseum that produce high levels of pectin lyase (PL) and polygalacturonase (PG) simultaneously. METHODS AND RESULTS: A strain with high production of PL was transformed with the plasmid pAN52pgg2, containing the gene encoding PG of P. griseoroseum, under control of the gpd promoter gene from Aspergillus nidulans. Southern blot analysis demonstrated that all strain had at least one copy of pAN52pgg2 integrated into the genome. The recombinant strain P. griseoroseum T20 produced levels of PL and PG that were 266- and 27-fold greater, respectively, than the wild-type strain. Furthermore, the extracellular protein profile of recombinant T20 showed two protein bands of c. 36 and 38 kDa, associated with PL and PG, respectively. CONCLUSIONS: This recombinant strain T20 produces PL and PG using carbon sources of low costs, and an enzyme preparation that is free of cellulolytic and proteolytic activities. SIGNIFICANCE AND IMPACT OF THE STUDY: PL and PG play an important role in the degradation of pectin. Owing to their use in the juice and wines industries, there is a growing interest in the inexpensive production of these enzymes. This work describes an efficient system of protein expression and secretion using the fungus P. griseoroseum.


Assuntos
Microbiologia Industrial , Penicillium/enzimologia , Poligalacturonase/biossíntese , Polissacarídeo-Liases/biossíntese , Aspergillus nidulans/genética , Meios de Cultura , Engenharia Genética , Penicillium/genética , Plasmídeos , Poligalacturonase/genética , Polissacarídeo-Liases/genética , Regiões Promotoras Genéticas , Transformação Genética
15.
J Biomed Mater Res A ; 98(4): 535-43, 2011 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-21681946

RESUMO

Depending on the final application envisaged for a given biomaterial, many surfaces must be modified before use. The material performance in a biological environment is mainly mediated by its surface properties that can be improved using suitable modification methods. The aim of this work was to coat poly(dimethyl siloxane) (PDMS) surfaces with biosurfactants (BSs) and to evaluate how these compounds affect the PDMS surface properties. BSs isolated from four probiotic strains (Lactococcus lactis, Lactobacillus paracasei, Streptococcus thermophilus A, and Streptococcus thermophilus B) were used. Bare PDMS and PDMS coated with BSs were characterized by contact angle measurements, infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The influence of the surface modifications on the materials blood compatibility was studied through thrombosis and hemolysis assays. The cytotoxicity of these materials was tested against rat peritoneal macrophages. AFM results demonstrated the successful coating of the surfaces. Also, by contact angle measurements, an increase of the coated surfaces hydrophilicity was seen. Furthermore, XPS analysis indicated a decrease of the silicon content at the surface, and ATR-FTIR results showed the presence of BS characteristic groups as a consequence of the modification. All the studied materials revealed no toxicity and were found to be nonhemolytic. The proposed approach for the modification of PDMS surfaces was found to be effective and opens new possibilities for the application of these surfaces in the biomedical field.


Assuntos
Dimetilpolisiloxanos/química , Probióticos/química , Tensoativos/química , Animais , Materiais Biocompatíveis/química , Materiais Revestidos Biocompatíveis/química , Teste de Materiais , Microscopia de Força Atômica , Espectroscopia Fotoeletrônica , Ratos , Ratos Wistar , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Tensoativos/isolamento & purificação
16.
Colloids Surf B Biointerfaces ; 84(1): 1-5, 2011 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-21247740

RESUMO

In the last years, researches developed with biosurfactants for application in the medical area have been revealing the promising biological activities of these biomolecules. In this work the antimicrobial and anti-adhesive properties of a biosurfactant Rufisan isolated from the yeast Candida lipolytica UCP 0988, growth in a medium supplemented with ground nut refinery residue was determined against several microorganisms. The biosurfactant was able to reduce the water surface tension from 70 to 25.3 mN/m and showed a critical micelle concentration (CMC) of 0.03%. The biosurfactant was isolated after 72 h of fermentation and was tested in concentrations varying from 0.75 to 12 mg/l. The highest antimicrobial activities were observed against Streptococcus agalactiae, Streptococcus mutans, Streptococcus mutans NS, Streptococcus mutans HG, Streptococcus sanguis 12, Streptococcus oralis J22 at a concentration superior to the biosurfactant critical micelle concentration. Moreover, the biosurfactant showed anti-adhesive activity against most of the microorganisms tested. As far as we know, this is the first compilation of data on antimicrobial and anti-adhesive activities of a biosurfactant obtained from a Candida strain against such a broad group of microorganisms. The results obtained in this work showed that the biosurfactant from C. lipolytica is a potential antimicrobial and/or anti-adhesive agent for several biomedical applications.


Assuntos
Anti-Infecciosos , Candida/metabolismo , Tensoativos , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Candida/classificação , Escherichia/efeitos dos fármacos , Lactobacillus/efeitos dos fármacos , Streptococcus/efeitos dos fármacos , Tensoativos/metabolismo
17.
J Dairy Sci ; 94(1): 66-76, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21183018

RESUMO

The evidence that biologically active food components are key environmental factors affecting the incidence of many chronic diseases is overwhelming. However, the full extent of such components in our diet is unknown, as is our understanding of their mechanisms of action. Beyond the interaction of these food components with the gut and intestinal immune functions, whey proteins such as lactoferrin are being tested as anticancer agents. Lactoferrin is an iron-binding protein that has been reported to inhibit several types of cancer. In the present work, the effects of bovine milk lactoferrin on human breast cancer HS578T and T47D cells were studied. The cells were either untreated or treated with lactoferrin concentrations ranging from 0.125 to 125 µM. Lactoferrin decreased the cell viability of HS578T and T47D by 47 and 54%, respectively, and increased apoptosis about 2-fold for both cell lines. Proliferation rates decreased by 40.3 and 63.9% for HS578T and T47D, respectively. For the T47D line, cell migration decreased in the presence of the protein. Although the mechanisms of action are not fully known, the results gathered in this work suggest that lactoferrin interferes with some of the most important steps involved in cancer development.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Lactoferrina/farmacologia , Leite/química , Animais , Apoptose/efeitos dos fármacos , Neoplasias da Mama/patologia , Bovinos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Feminino , Humanos
18.
Colloids Surf B Biointerfaces ; 81(1): 20-6, 2010 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-20638249

RESUMO

Poly(dimethyl siloxane) elastomer, (PDMS) is widely used as a biomaterial. However, PDMS is very hydrophobic and easily colonized by several bacteria and yeasts. Consequently, surface modification has been used to improve its wettability and reduce bacterial adhesion. The aim of this work was to modify the PDMS surface in order to improve its hydrophilicity and bacterial cell repulsion to be used as a biomaterial. Plasma was used to activate the PDMS surface and sequentially promote the attachment of a synthetic surfactant, Pluronic F-68, or a polymer, Poly(ethylene glycol) methyl methacrylate, PEGMA. Bare PDMS, PDMS argon plasma activated, PDMS coated with Pluronic F-68 and PEGMA-grafted PDMS were characterized by contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The influence of the surface modifications on blood compatibility of the materials was evaluated by thrombosis and haemolysis assays. The cytotoxicity of these materials was tested for mouse macrophages. After modification, AFM results suggest the presence of a distinct layer at the surface and by the contact angle measures it was observed an increase of hydrophilicity. XPS analysis indicates an increase of the oxygen content at the surface as a result of the modification. All the studied materials revealed no toxicity and were found to be non-haemolytic or in some cases slightly haemolytic. Therefore, plasma was found to be an effective technique for the PDMS surface modification.


Assuntos
Materiais Biocompatíveis/química , Dimetilpolisiloxanos/química , Teste de Materiais/métodos , Animais , Materiais Biocompatíveis/farmacologia , Tecnologia Biomédica/métodos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Dimetilpolisiloxanos/farmacologia , Elastômeros/química , Elastômeros/farmacologia , Hemólise/efeitos dos fármacos , Interações Hidrofóbicas e Hidrofílicas , Macrófagos Peritoneais/citologia , Macrófagos Peritoneais/efeitos dos fármacos , Metacrilatos/química , Camundongos , Camundongos Endogâmicos BALB C , Microscopia de Força Atômica , Espectroscopia Fotoeletrônica , Poloxâmero/química , Polietilenoglicóis/química , Coelhos , Propriedades de Superfície
19.
Lett Appl Microbiol ; 50(4): 419-24, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20184670

RESUMO

AIMS: The aim of this study was to determine the antimicrobial and antiadhesive properties of a biosurfactant isolated from Lactobacillus paracasei ssp. paracasei A20 against several micro-organisms, including Gram-positive and Gram-negative bacteria, yeasts and filamentous fungi. METHODS AND RESULTS: Antimicrobial and antiadhesive activities were determined using the microdilution method in 96-well culture plates. The biosurfactant showed antimicrobial activity against all the micro-organisms assayed, and for twelve of the eighteen micro-organisms (including the pathogenic Candida albicans, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus agalactiae), the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were achieved for biosurfactant concentrations between 25 and 50 mg ml(-1). Furthermore, the biosurfactant showed antiadhesive activity against most of the micro-organisms evaluated. CONCLUSIONS: As far as we know, this is the first compilation of data on antimicrobial and antiadhesive activities of biosurfactants obtained from lactobacilli against such a broad group of micro-organisms. Although the antiadhesive activity of biosurfactants isolated from lactic acid bacteria has been widely reported, their antimicrobial activity is quite unusual and has been described only in a few strains. SIGNIFICANCE AND IMPACT OF THE STUDY: The results obtained in this study regarding the antimicrobial and antiadhesive properties of this biosurfactant opens future prospects for its use against micro-organisms responsible for diseases and infections in the urinary, vaginal and gastrointestinal tracts, as well as in the skin, making it a suitable alternative to conventional antibiotics.


Assuntos
Anti-Infecciosos/isolamento & purificação , Lactobacillus/química , Tensoativos/química , Tensoativos/farmacologia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Candida albicans/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Tensoativos/isolamento & purificação
20.
Phytomedicine ; 2010 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-20096550

RESUMO

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

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