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Acetic acid- and phenyl-p-benzoquinone-induced overt pain-like behavior depends on spinal activation of MAP kinases, PI3K and microglia in mice

Pavao-de-Souza, Gabriela F.; Zarpelon, Ana C.; Tedeschi, Giovana C.; Mizokami, Sandra S.; Sanson, Joice S.; Cunha, Thiago M.; Ferreira, Sergio H.; Cunha, Fernando Q.; Casagrande, Rubia; Verri, Waldiceu A., Jr.
Fonte: PERGAMON-ELSEVIER SCIENCE LTD; OXFORD Publicador: PERGAMON-ELSEVIER SCIENCE LTD; OXFORD
Tipo: Artigo de Revista Científica
ENG
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The acetic acid and phenyl-p-benzoquinone are easy and fast screening models to access the activity of novel candidates as analgesic drugs and their mechanisms. These models induce a characteristic and quantifiable overt pain-like behavior described as writhing response or abdominal contortions. The knowledge of the mechanisms involved in the chosen model is a crucial step forward demonstrating the mechanisms that the candidate drug would inhibit because the mechanisms triggered in that model will be addressed. Herein, it was investigated the role of spinal mitogen-activated protein (MAP) kinases ERK (extracellular signal-regulated kinase), JNK (Jun N-terminal Kinase) and p38, PI3K (phosphatidylinositol 3-kinase) and microglia in the writhing response induced by acetic acid and phenyl-p-benzoquinone, and flinch induced by formalin in mice. Acetic acid and phenyl-p-benzoquinone induced significant writhing response over 20 min. The nociceptive response in these models were significantly and in a dose-dependent manner reduced by intrathecal pre-treatment with ERK (PD98059), JNK (SB600125), p38 (SB202190) or PI3K (wortmannin) inhibitors. Furthermore, the co-treatment with MAP kinase and PI3K inhibitors, at doses that were ineffective as single treatment...

"Avaliação da atividade antimicrobiana e citotóxica in vitro do vinagre a ácido acético: perspectiva na terapêutica de feridas" ; In vitro evaluation of antimicrobial and cytotoxicity activities of vinegar and acetic acid: perspectives for wound therapeutics Ribeirão Preto.

Utyama, Iwa Keiko Aida
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/09/2003 PT
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O uso correto de produtos químicos com ação antimicrobiana na terapêutica de feridas tem sido uma das preocupações dos profissionais da saúde. A temática em questão representa uma séria problemática agravada, principalmente, pela diversidade de opções, o que traz a insegurança sobre qual é a mais indicada, bem como, pelo uso indiscriminado o que pode resultar na seleção de cepas resistentes. Diante do exposto, foi estabelecido como objetivos: avaliar in vitro a atividade antimicrobiana do ácido acético e do vinagre por meio da Técnica de Difusão de Poço sobre as cepas de Pseudomonas aeruginosa, E. coli e Staphylococcus aureus; determinar a Concentração Inibitória Mínima (CIM); e revelar a citotoxicidade dos referidos produtos sobre Artemia salina Leach. Para análise estatística foi usado o teste de variância ANOVA – ONEWAY seguida do teste de comparações múltiplas; com nível de significância  = 5%. Assim sendo, pelo método de difusão de poço o vinagre branco, tinto (30,0 e 25,0%) e o ácido acético a 1,0 são mais eficazes que o ácido acético a 0,7%, vinagre branco e tinto a 10,0% (p<0.05) sobre as cepas de Pseudomonas aeruginosa e Escherichia coli. Vale considerar que os produtos analisados não apresentaram ação antimicrobiana sobre Staphylococcus aureus. A Concentração Inibitória Mínima (CIM) do ácido acético nas cepas avaliadas foi a 0...

"Estudos eletroquímicos e espectroscópicos da eletrooxidação de etanol, acetaldeído e ácido acético sobre Pt (110) modificada superficialmente por ósmio"; "Electrochemical and spectroscopics studies of ethanol, acetaldehyde and acetic acid electrooxidation on Pt(110) modified by osmium"

Colle, Vinicius Del
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/10/2006 PT
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Este trabalho descreve estudos eletroquímicos e espectroscópicos da eletrooxidação de etanol, acetaldeído e ácido acético sobre uma superfície de platina monocristalina de baixo índice de Miller 110 modificada por ósmio (Os). O eletrodo monocristalino de Pt(110) foi modificado por Os espontaneamente e pela aplicação de potencial. Os eletrodos foram caracterizados eletroquimicamente, de forma que foram obtidos valores baixos, intermediários e altos de Os sobre a superfície de Pt(110). A eletrooxidação de etanol sobre Pt(110) e Pt(110)/Os, analisada pelas técnicas de voltametria cíclica e cronoamperometria, mostrou que as densidades de corrente para essa reação foram maiores nos graus de recobrimento entre 0,51 – 0,61 ML. A partir dos resultados de FTIR in situ, verificou-se que a reação de oxidação de etanol difere em seus caminhos de acordo com o grau de recobrimento de Os. O caminho um sugere a quebra da ligação C—C com maior intensidade em graus de recobrimento entre 0,36 – 0,80 ML, formando espécies como COlinear, CHx e, posteriormente, CO2. O caminho dois mostra a formação de acetaldeído a partir de 0,4 V sobre os eletrodos Pt(110) e Pt(110)/Os, e que pode haver ainda a produção de CO e ácido acético a partir desse orgânico sobre eletrodos com HOs > 0...

Modelagem cinética da esterificação de sec-butanol com ácido acético e estudo de monitoramento em linha da reação com espectroscopia de infravermelho.; Kinetic modeling of esterification of sec-butanol with acetic acid and study of reaction on-line monitoring using near infrared spectroscopy.

Dias, Marcio Andrade
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 26/03/2012 PT
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A esterificação do sec-butanol com ácido acético, submetida à catálise homogênea, apresenta poucos resultados experimentais de cinética reacional e equilíbrio químico disponíveis na literatura. A presente dissertação visa determinar os parâmetros cinéticos e de equilíbrio químico desta reação de esterificação, empregando modelo cinético de 2ª ordem baseado em atividades. Os experimentos cinéticos foram realizados em reator batelada com auxílio da metodologia Karl Fischer para análise do teor de água e determinação do perfil de frações molares ao longo da reação. A principal dificuldade na modelagem desta esterificação consistiu em representar satisfatoriamente as não-idealidades da mistura em fase líquida, em espacial nas reações cuja fração molar inicial de ácido acético foi superior a 50%. Netas condições admitiu-se a ocorrência de dissociação do ácido acético levando ao surgimento de interações iônicas. O modelo empregado para obtenção das atividades, com base em frações molares, foi o NRTL. Este modelo representou bem as interações moleculares em condição de baixa acidez, mas apresentou desvios em condições de acidez e teores de água mais elevados. O estudo também visou o desenvolvimento de modelos de calibração para um método analítico on-line visando determinar o perfil de frações molares ao longo da reação. O método empregado foi a espectroscopia de infravermelho próximo (NIR)...

Efeito do pH e do ácido acético sobre a produção de bioinseticida por Bacillus thuringiensis a partir de glicerol proveniente da fabricação de biodiesel; Effect of pH and acetic acid on bioinsetice production by Bacillus thuringiensis using glycerol from biodiesel synthesis

Chagas, Marta Heloisa dos Reis
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 05/10/2012 PT
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Bacillus thuringiensis é uma bactéria do solo, gram-positiva, que se destaca pela capacidade de sintetizar um cristal protéico, adjacente ao esporo, responsável pela ação tóxica contra diversas espécies de dípteros, como a larva do mosquito Aedes aegypti, o qual é o principal vetor da dengue. A dengue hoje é uma das doenças de maior preocupação para as agências de saúde brasileiras, uma vez que o Brasil possui temperatura e condições socio-econômicas que favorecem proliferação do mosquito transmissor. O Brasil se destaca por desenvolver combustíveis alternativos aos combustíveis de origem petrolífera, como etanol e biodiesel. Porém, durante a reação de transesterificação de óleos/gorduras para a produção de biodiesel é gerado também glicerina e, por não haver uma demanda deste sub-produto no mercado mundial, seu destino se tornou um problema e um desafio para as indústrias de biodiesel. Logo, desenvolver um bioinseticida para o combate da dengue empregando a glicerina como fonte de carbono é uma forma de encontrar novas aplicações para a glicerina e contribuir para o controle de uma doença de impacto nacional. Estudos realizados comprovaram que o ácido acético é um composto produzido e consumido pelas células de Bacillus thuringiensis durante seu crescimento. Além disso...

Effects of acetylsalicylic acid and acetic acid solutions on VX2 liver carcinoma in rabbits: in vivo analysis

Saad-Hossne, Rogério; Prado, René Gamberini; Hossne, William Saad
Fonte: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia Publicador: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia
Tipo: Artigo de Revista Científica Formato: 299-308
ENG
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OBJETIVO: Analisar os efeitos das soluções de aspirina e de ácido acético, in vivo, em fígado de coelhos portadores de tumor hepático VX2, verificando o efeito histolítico e anatomo-patológico das soluções e eventuais alterações bioquímicas hepáticas. MÉTODOS: Utilizou-se 48 coelhos, divididos em 2 protocolos experimentais(3 e 4), subdivididos em 3 grupos cada. Após 4 dias da implantação do tumor no fígado, procedeu-se a laparotomia mediana, com injeção de 0,4 ml da solução de aspirina (5,0%), de ácido acético (5,0%) e solução salina; o sacrifício ocorreu apos 24 horas (protocolo 3) e 11 dias (protocolo 4); avaliou-se o peso, evolução clinica, dosagens bioquímicas, cavidade abdominal e torácica e microscopia do fígado. RESULTADOS: Não foram observadas alterações na evolução clinica, peso e nas dosagens bioquímicas, apenas elevação da fosfatase alcalina no grupo controle do protocolo 4. Observamos desaparecimento do tumor em ambos os protocolos. CONCLUSÃO: As soluções de ácido acético e ácido acetilsalicílico acarretam destruição do tumor hepático experimental.; PURPOSE: To analyze, in vitro, the effects of acetylsalicylic acid (aspirin) and acetic acid solutions on VX2 carcinoma cells in the liver of rabbits with VX2 hepatic tumors; to determine the histolytic and anatomopathological characteristics of the solutions; and to evaluate the eventual biochemical and hepatic changes. METHODS: A total of 48 rabbits were evaluated. The animals were randomized into two groups...

Effects of acetylsalicylic acid and acetic acid solutions in VX2 carcinoma cells. In vitro analysis

Saad-Hossne, Rogério; Prado, René Gamberini; Hossne, William Saad
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 151-154
ENG
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Purpose: To analyze, in vitro, the effects of acetylsalicylic acid (aspirin) and acetic acid solutions on VX2 carcinoma cells in suspension and to examine the correlation between these effects and neoplastic cell death. Methods: The VX2 tumor cells (107 cells/ml) were incubated in solutions containing differing concentrations (2.5% and 5%) of either acetylsalicylic acid or acetic acid, or in saline solution (controls). Every five minutes, cell viability was tested (using the trypan blue test) and analyzed under light microscopy. Results: Tumor cell viability (in %) decreased progressively and, by 30 minutes, neoplastic cell death had occurred in all solutions. Conclusion: Based on this experimental model and the methodology employed, we conclude that these solutions cause neoplastic cell death in vitro.

Effects of ethanol and acetic acid on the transport of malic acid and glucose in the yeast Schizosaccharomyces pombe: implications in wine deacidification

Sousa, Maria João; Mota, M.; Leão, Cecília
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em 15/02/1995 ENG
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Published by Elsevier on behalf of the Federation of European Microbiological Societies; Ethanol and acetic acid, at concentrations which may occur during wine-making, inhibited the transport of ι-malic acid in Schizosaccharomyces pombe. The inhibition was non-competitive, the decrease of the maximum initial velocity following exponential kinetics. Glucose transport was not significantly affected either by ethanol (up to 13%, w/v) or by acetic acid (up to 1.5%, w/v). The uptake of labelled acetic acid followed simple diffusion kinetics, indicating that a carrier was not involved in its transport. Therefore, the undissociated acid appears to be the only form that enters the cells and is probably responsible for the toxic effects. Accordingly, deacidification by Ss. pombe during wine fermentation should take place before, rather than after, the main alcoholic fermentation by Saccharomyces cerevisiae.; NATO Science for Stability POPORTOFOOD; Junta Nacional de Investigação Científica e Tecnológica (JNICT).

Effects of acetic acid, ethanol and SO2 on the removal of volatile acidity from acidic wines by two Saccharomyces cerevisiae commercial strains

Moura, A. Vilela; Schuller, Dorit Elisabeth; Faia, A. Mendes; Côrte-Real, Manuela
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em //2010 ENG
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Herein we report the influence of different combinations of initial concentration of acetic acid and ethanol on the removal of acetic acid from acidic wines by two commercial Saccharomyces cerevisiae strains S26 and S29. Both strains reduced the volatile acidity of an acidic wine (1.0 g l-1 acetic acid and 11% (v/v) ethanol) by 78% and 48%, respectively. Acetic acid removal by both strains was associated with a decrease in ethanol concentration of about 0.7 – 1.2% (v/v). Strain S26 revealed better removal efficiency due to its higher tolerance to stress factors imposed by acidic wines. We also demonstrate that the strong anti-oxidant and antiseptic effect of sulphur dioxide (SO2) concentrations up to 170 mg l-1 inhibit the ability of both strains to reduce the volatile acidity of an acidic wine under our experimental conditions. Therefore, deacidification should be carried out either in wines stabilized by filtration or in wines with SO2 concentrations below 75 mg l-1. Deacidification of wines with the better performing strain S26 was associated with changes in the concentration of volatile compounds. The most pronounced increase was observed for isoamyl acetate (banana) and ethyl hexanoate (apple, pineapple), with an 18- and 25-fold increment...

Simple and solvent-free methodology for simultaneous quantification of methanol and acetic acid content of plant polysaccharides based on headspace solid phase microextraction-gas chromatography (HS-SPME-GC-FID)

Nunes, Cláudia; Rocha, Sílvia M.; Saraiva, Jorge; Coimbra, Manuel A.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
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A simple and solvent-free methodology is proposed for the simultaneous determination of methanol and acetic acid content of any type of plant cell wall polysaccharides. The methanol and acetic acid, released by saponification, are extracted from the headspace of the aqueous solution by solid phase microextraction (HS-SPME) using a DVB/Carboxen/PDMS fibre. The analytes are separated by gas chromatography and detected using a flame ionization detector (GC-FID). The quantification of methanol and acetic acid is done using external calibration curves. A linear relationship between the concentration of methanol (40–100 mg L−1) and acetic acid (25–105 mg L−1) and their GC peak area was observed (r2=0.987 and 0.988, respectively) with a reproducibility of 10%. HS-SPME-GC-FID revealed to be a clean, simple, fast and reliable methodology for the determination of the methanol and acetic acid content of cell wall polysaccharide extracts.

Anticoccidial effects of acetic acid on performance and pathogenic parameters in broiler chickens challenged with Eimeria tenella

Abbas,Rao Z.; Munawar,Shokat H.; Manzoor,Zahid; Iqbal,Zafar; Khan,Muhammad N.; Saleemi,Muhammad K.; Zia,Muhammad A.; Yousaf,Arfan
Fonte: Colégio Brasileiro de Patologia Animal - CBPA; Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) Publicador: Colégio Brasileiro de Patologia Animal - CBPA; Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA)
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2011 EN
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The objective of the present study was to evaluate the anticoccidial effect of the different concentrations of the acetic acid in the broiler chickens in comparison with the amprolium anticoccidial. A total of 198 chicks were placed 11 per pen with three pens per treatment. The different concentrations (1%, 2% and 3%) of acetic acid and amproilum (at the dose rate of 125ppm) were given to the experimental groups in drinking water from 10-19th days of age. One group was kept as infected non medicated control and one as non infected non medicated control. All the groups were inoculated orally with 75,000 sporulated oocysts at the 12th day of age except non infected non medicated control. Anticoccidial effect was evaluated on the basis of performance (weight gain, feed conversion ratio) and pathogenic (oocyst score, lesion score and mortality %age) parameters. Among acetic acid medicated groups, the maximum anticoccidial effect was seen in the group medicated with 3% acetic acid followed by 2% and 1% acetic acid medicated groups. Amprolium and 3% acetic acid were almost equivalent in suppressing the negative performance and pathogenic effects associated with coccidiosis (Eimeria tenella) challenge. In summary, acetic acid has the potential to be used as alternative to chemotherapeutic drugs for Eimeria tenella control. Concentration-dependent anticoccidial effect of acetic acid suggests that further studies should be carried out to determine the possible maximum safe levels of acetic acid with least toxic effects to be used as anticoccidial.

Effects of acetylsalicylic acid and acetic acid solutions on VX2 liver carcinoma in rabbits: in vivo analysis

Saad-Hossne,Rogério; Prado,René Gamberini; Hossne,William Saad
Fonte: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia Publicador: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2007 EN
Relevância na Pesquisa
687.8363%
PURPOSE: To analyze, in vitro, the effects of acetylsalicylic acid (aspirin) and acetic acid solutions on VX2 carcinoma cells in the liver of rabbits with VX2 hepatic tumors; to determine the histolytic and anatomopathological characteristics of the solutions; and to evaluate the eventual biochemical and hepatic changes. METHODS: A total of 48 rabbits were evaluated. The animals were randomized into two groups, protocol 3 (study group) and protocol 4 (controls), and each group was then subdivided into 3 subgroups. Four days after implantation of the tumor in the liver, median laparotomy was performed with a 0.4-ml injection of a solution of either aspirin (5.0%), acetic acid (5.0%) or saline. The animals were sacrificed after 24 hours (protocol 3) or after 11 days (protocol 4). Body weight, clinical evolution and biochemical levels, as well as the abdominal and thoracic cavities, were evaluated, and liver microscopy was performed. RESULTS: No changes in clinical evolution, body weight or biochemical levels were reported. However, an increase in alkaline phosphatase was observed in protocol 4 (controls). The tumor was eliminated in both protocols. CONCLUSION: Acetylsalicylic acid and acetic acid solutions cause the destruction of experimental hepatic tumors.

Inhibitory effect of acetic acid on bioconversion of xylose in xylitol by Candida guilliermondii in sugarcane bagasse hydrolysate

Silva,Débora D.V.; Felipe,Maria G.A.; Mancilha,Ismael M.; Luchese,Rosa H.; Silva,Sílvio S.
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2004 EN
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Sugarcane bagasse hydrolysate (initial acetic acid concentration = 3.5g/L), was used as a fermentation medium for conversion of xylose into xylitol by the yeast Candida guilliermondii FTI 20037. Acetic acid (2.0g/L) was added to the medium at different times of fermentation, with the aim of evaluating its effects on the bioconversion process. The addition of acetic acid to the medium after 12h of fermentation resulted in the strongest inhibition of the yeast metabolism. In this case, the xylose consumption and cell growth were, respectively, 23.22 and 11.24% lower than when acid was added to the medium at the beginning of fermentation. As a consequence of the inhibitory effect, lower values of the xylitol yield (0.39g/g) and productivity (0.22g/L.h) were observed, corresponding to a reduction of 36 and 48%, respectively, in relation to the values obtained with the addition of acetic acid after other fermentation times. The results obtained allowed to conclude that, under the experimental conditions employed in this work, the inhibitory effect of acetic acid on the xylose-xylitol bioconversion depends on the fermentation time when this acid was added, and not only on its concentration in the medium.

Indole-3-acetic acid metabolism in normal and dwarf micropropagated banana plants (Musa spp. AAA)

Zaffari,Gilmar Roberto; Peres,Lázaro Eustáquio Pereira; Tcacenco,Fernando Adami; Kerbauy,Gilberto Barbante
Fonte: Brazilian Journal of Plant Physiology Publicador: Brazilian Journal of Plant Physiology
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2002 EN
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Nanism is one of the most frequent type of mutant in micropropagated banana plants from the Cavendish subgroup. The present study aimed at studying some of the hormone factors involved in this type of mutation. Rhizomes from normal and dwarf plants from the cultivar Grand Naine were incubated for 5 d in the presence of [³H]-L-tryptophan, [³H]-indole-3-acetic acid and gibberellin, to quantify the endogenous levels of indole-3-acetic acid-ester, indole-3-acetic acid-amide, free indole-3-acetic acid, and cytokinins. The endogenous levels of indole-3-acetic acid and its ester- and amide-conjugated forms were measured in normal and dwarf plants incubated for 30 d with gibberellin, indole-3-acetic acid, and L- and D-tryptophan. In normal plants, the use of [³H]-L-tryptophan resulted in higher levels of radioactivity in the retention times corresponding to indole-3-acetic acid, indole-3-acetic acid-aspartate, indole-3-acetic acid-glycine and indole-3-acetic acid-alanine. These values were higher than those observed in dwarf plants. Higher quantities of radioactive indole-3-acetic acid and of amide-forms in dwarf plants occurred in rhizomes treated with [³H]-L-tryptophan and gibberellin simultaneously. The endogenous levels of total cytokinins were the same in both materials...

Effects of epidermal growth factor administration on repair of acetic acid-induced colonic ulcerations in rats

Ribbons, K.; Howarth, G.; Ford, W.; George-Nascimento, C.; Bourne, A.; Read, L.
Fonte: HARWOOD ACAD PUBL GMBH Publicador: HARWOOD ACAD PUBL GMBH
Tipo: Artigo de Revista Científica
Publicado em //1997 EN
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The effect of subcutaneous and luminal epidermal growth factor (EGF) administration on acetic acid-induced colonic ulceration was determined in adult rats. Application of acetic acid to the distal colonic lumen caused epithelial denudation, mucosal ulceration and inflammation in the exposed segment. Re-epithelialization was detectable 5 to 7 days later, with near-complete resolution of the lesion by 14 days post-injury. Luminal EGF (1.6 mg/kg bw/day) or subcutaneous EGF (200 micromilligrams/kg bw/day), administered for 4 or 6 days from the time of ulceration failed to enhance re-epithelialization of the acid-exposed segment. However, mucosal and submucosal thickening was attenuated 20-40% by subcutaneous EGF, reflecting a reduction in edema. Luminal EGF had a similar but less substantial effect in the submucosa, but was more effective at attenuating muscularis thickening adjacent to the lesion. In conclusion, administration of exogenous EGF for up to 6 days failed to enhance re-epithelialization of acetic acid-induced colonic ulcerations but did attenuate the associated edematous response.; Karen A. Ribbons, Gordon S. Howarth, W. D. Andrew Ford, Carlos George-Nascimento, Anthony J. Bourne, Leanna C. Read

Decreasing acetic acid accumulation by a glycerol overproducing strain of Saccharomyces cerevisiae by deleting the ALD6 aldehyde dehydrogenase gene

Eglinton, J.; Heinrich, A.; Pollnitz, A.; Langridge, P.; Henschke, P.; de Barros Lopes, M.
Fonte: John Wiley & Sons Ltd Publicador: John Wiley & Sons Ltd
Tipo: Artigo de Revista Científica
Publicado em //2002 EN
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Glycerol is a major fermentation product of Saccharomyces cerevisiae that contributes to the sensory character of wine. Diverting sugar to glycerol overproduction and away from ethanol production by overexpressing the glycerol 3-phosphate dehydrogenase gene,GPD2, caused S. cerevisiae to produce more than twice as much acetic acid as the wild-type strain (S288C background) in anaerobic cell culture. Deletion of the aldehyde dehydrogenase gene, ALD6, in wild-type and GPD2 overexpressing strains (GPD2-OP) decreased acetic acid production by three- and four-fold, respectively. In conjunction with reduced acetic acid production, the GPD2-OP ald6Delta strain produced more glycerol and less ethanol than the wild-type. The growth rate and fermentation rate were similar for the modified and wild-type strains, although the fermentation rate for the GPD2 ald6Delta strain was slightly less than that of the other strains from 24h onwards. Analysis of the metabolome of the mutants revealed that genetic modification affected the production of some secondary metabolites of fermentation, including acids, esters, aldehydes and higher alcohols, many of which are flavour-active in wine. Modification of GPD2 and ALD6 expression represents an effective strategy to increase the glycerol and decrease the ethanol concentration during fermentation...

Novel wine yeast with mutations in YAP1 that produce less acetic acid during fermentation

Cordente, A.; Cordero-Bueso, G.; Pretorius, I.; Curtin, C.
Fonte: Elsevier Science BV Publicador: Elsevier Science BV
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
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Acetic acid, a byproduct formed during yeast alcoholic fermentation, is the main component of volatile acidity (VA). When present in high concentrations in wine, acetic acid imparts an undesirable ‘vinegary’ character that results in a significant reduction in quality and sales. Previously, it has been shown that sake´ yeast strains resistant to the antifungal cerulenin produce significantly lower levels of VA. In this study, we used a classical mutagenesis method to isolate a series of cerulenin-resistant strains, derived from a commercial diploid wine yeast. Four of the selected strains showed a consistent low-VA production phenotype after small-scale fermentation of different white and red grape musts. Specific mutations in YAP1, a gene encoding a transcription factor required for oxidative stress tolerance, were found in three of the four low-VA strains. When integrated into the genome of a haploid wine strain, the mutated YAP1 alleles partially reproduced the low-VA production phenotype of the diploid cerulenin-resistant strains, suggesting that YAP1 might play a role in (regulating)acetic acid production during fermentation. This study offers prospects for the development of low-VA wine yeast starter strains that could assist winemakers in their effort to consistently produce wine to definable quality specifications.; Antonio G. Cordente...

Ethanol and acetic acid production from carbon monoxide in a “clostridium” strain in batch and continuous gas-fed bioreactors

Abubackar, Haris Nalakath; Veiga, María C.; Kennes, Christian
Fonte: Multidisciplinary Digital Publishing Institute Publicador: Multidisciplinary Digital Publishing Institute
Tipo: Artigo de Revista Científica
ENG
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The effect of different sources of nitrogen as well as their concentrations on the bioconversion of carbon monoxide to metabolic products such as acetic acid and ethanol by Clostridium autoethanogenum was studied. In a first set of assays, under batch conditions, either NH4Cl, trypticase soy broth or yeast extract (YE) were used as sources of nitrogen. The use of YE was found statistically significant (p < 0.05) on the product spectrum in such batch assays. In another set of experiments, three bioreactors were operated with continuous CO supply, in order to estimate the effect of running conditions on products and biomass formation. The bioreactors were operated under different conditions, i.e., EXP1 (pH = 5.75, YE 1g/L), EXP2 (pH = 4.75, YE 1 g/L) and EXP3 (pH = 5.75, YE 0.2 g/L). When compared to EXP2 and EXP3, it was found that EXP1 yielded the maximum biomass accumulation (302.4 mg/L) and products concentrations, i.e., acetic acid (2147.1 mg/L) and ethanol (352.6 mg/L). This can be attributed to the fact that the higher pH and higher YE concentration used in EXP1 stimulated cell growth and did, consequently, also enhance metabolite production. However, when ethanol is the desired end-product, as a biofuel, the lower pH used in EXP2 was more favourable for solventogenesis and yielded the highest ethanol/acetic acid ratio...

Genetic adaptive mechanisms mediating response and tolerance to acetic acid stress in the human pathogen Candida glabrata: role of the CgHaa1-dependent signaling pathway

Bernardo, Ruben T.; Cunha, Diana V.; Wang, Can; Chibana, Hiroji; Silva, Sónia Carina; Sá-Correia, Isabel; Azeredo, Joana; Butler, Geraldine; Mira, Nuno P.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em 13/09/2015 ENG
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C. glabrata is a commensal found in the human genitourinary tract but under certain conditions this harmless colonization evolves to a mucosal infection and, in more serious cases, to disseminated mycosis. To thrive in the acidic vaginal tract C. glabrata has to cope with the presence of a competing commensal microbiota known to restrain the overgrowth of pathogens through the production of acetic and lactic acids, among other interference effects. The persistent emergence of C. glabrata strains resistant to currently used antifungals demands the implementation of novel therapeutic strategies based on non-conventional targets. Genes contributing to increase C. glabrata competitiveness in the vaginal tract by mediating tolerance to the organic acids found therein are a cohort of interesting and yet unexplored therapeutic targets. Tolerance mechanisms of C. glabrata to acetic acid at low pH are poorly studied but much knowledge was gathered in Saccharomyces cerevisiae (Mira et al 2010a; 2010b; 2011; 2010c). In particular, the central role of the ScHaa1 transcription factor in mediating S. cerevisiae tolerance to acetic acid stress was demonstrated (Mira et al 2010b; 2011; 2010c). In this work it is shown that CgHaa1, an orthologue of ScHaa1...

Antibacterial Power of Sodium Hypochlorite Combined with Surfactants and Acetic Acid

Giardino,Luciano; Estrela,Carlos; Mohammadi,Zahed; Palazzi,Flavio
Fonte: Fundação Odontológica de Ribeirão Preto Publicador: Fundação Odontológica de Ribeirão Preto
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 EN
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The aim of this ex vivo study was to compare the antibacterial power of 1% NaOCl with 1% acetic acid, 5.25% NaOCl and two commercially available NaOCl modified with surfactants in bovine root dentin. A total of 120 dentin tubes prepared from intact bovine incisors were infected for 21 days with Enterococcus faecalis and randomly divided into six groups as follows: 5.25%NaOCl; Hypoclean; Chlor-Xtra; 1% NaOCl with 1% acetic acid; infected dentin tubes (positive control); and sterile dentin tubes (negative control). At experimental times of 0, 7, 14, 21 and 28 days, dentin chips were collected using sequential round burs with increasing diameters in separate test tubes containing 3 mL of freshly prepared BHI. Statistical analysis were performed using parametric methods (one-way ANOVA, and Bonferroni's multiple comparisons test, α=0.01). After culturing, the number of colony-forming units (CFU) was counted. All the NaOCl solutions showed small number of CFU over 28 days. ChlorXtra and Hypoclean had the smallest number of CFU at all times with greater antimicrobial efficacy than 5.25% NaOCl and 1% NaOCl solution with 1% acetic acid.