221 resultados para LACTIC ACID BACTERIA


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Avaliou-se o efeito da adição do fubá de milho no mosto de xarope de cana e o tratamento ácido do pé-de-cuba sobre a microbiota do processo fermentativo, acidez do vinho, grau alcoólico, rendimento e composição da cachaça. O delineamento experimental utilizado foi o de blocos casualizados, no esquema fatorial 2x3 e cinco repetições. A metodologia empregada e as análises foram as recomendadas pelo setor aguardenteiro. Os resultados permitiram concluir que a adição do ácido sulfúrico no pé-de-cuba transferiu a acidez para o vinho, não influenciando na viabilidade das leveduras, rendimento e composição da cachaça. Por outro lado, a acidificação do meio controlou as bactérias láticas no pé-de-cuba. A adição do fubá aumentou a concentração de bactérias lácticas ao final do processo fermentativo e dos álcoois homólogos superiores na cachaça, particularmente, os álcoois propílico e isobutílico.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Nitroaromatic compounds such as nifuroxazide are used in many human enteropathogenic bacteria infections without causing an increase in the plasmidial antibiotic resistance of the aerobic Gram-negative intestinal Enterobacteriaceae. For these reasons, these compounds have been synthesized using the rational approach of Topliss' decision tree. Generally. this approach allows us to obtain the most active derivative from the series in a few steps. These compounds were tested against Mycobacterium tuberculosis in vitro and the most active of the series identified. A new lead for potential tuberculostatic activity has been predicted and will be used in further QSAR studies. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

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Considering the high incidence of dogs with acute bacterial cystitis (BC) and the relationship among inflammation, genotoxicity, and carcinogenesis, we conducted a case-control study comparing the frequency of deoxyribonucleic acid (DNA) lesions assessed by the comet assay between disease-free animals (13 males and 13 females) and cytology-confirmed cases of acute BC (12 males and 12 females), which was mainly caused by Staphylococcus sp. (40%) and Escherichia coli (35%). The results show no increase in DNA damage in cells obtained by bladder washings and no influence of age, sex, and breed due to acute BC. In conclusion, DNA damage was seemingly not associated with the infection by specific bacteria.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Objectives. The aim of this in vivo study was to evaluate the human dental pulp response when a one-bottle adhesive system was applied on etched or unetched deep dentine.Methods. Eighteen class V deep cavity preparations were divided in three groups: group 1-total etching + two coats of single bond (SB) + composite resin (Z-100); group 2-enamel etching + two coats of SB + Z-100, group 3-cavity floor lined with a calcium hydroxide liner (Dycal) + acid-etching of enamel and lateral walls + two coats of SB + Z-100. Two teeth were used as intact control group. After 30 days the teeth were extracted and processed through H and E, Masson's trichrome and Brown and Brenn staining techniques.Results. Moderate inflammatory response, disorganization of pulp tissue, as well as, deposition of thin layer of reactionary dentin were observed in group 1 teeth in which the remaining dentin thickness (RDT) was less than 300 mum. These histological findings appear to be related to long resin tags formation and bonding agent diffusion through dentinal tubules. In group 2, slight inflammatory response was observed only in one tooth in which the RDT was 162 mum. In group 3, all the teeth showed normal histological characteristics which were similar to the intact control group. Presence of bacteria was not correlated with the intensity of pulpal response. The patients reported no symptoms during the experiment. Radiographic evaluation showed no periapical pathology for any of the teeth,Significance and conclusions. Acid-etched deep dentin (RDT less than 300 mum) lined with SB causes more intense pulpal response than unetched deep dentin. Based on the results observed in the present study and the conditions in which it was carried out, we recommend the application of a biocompatible liner before etching deep dentin and applying SB. (C) 2002 Academy of Dental Materials. Published by Elsevier B.V. Ltd. All rights reserved.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Experiments were carried out on the antibacterial effects of a commercial formic acid-propionic acid mixture (Bio-add(TM)) against different Salmonella serptj pes. The preparation exerted a strong antibacterial effect on S. typhimurium strain F98 in artificially contaminated feed. After 28 days storage, the bactericidal effect was still considerable. When chickens were reared on feed that had been treated with Bio-add(TM) and artificially contaminated with different serotypes, S. enteritidis, S. typhimurium and S. agona were not isolated from the caecal contents, but S. infantis was. No organisms of this strain were isolated when a lower feed-contamination rate of bacteria was used.

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The ethanol production in Brazil is carried out by fed-batch or continuous process with cell recycle, in such way that bacterial contaminants are also recycled and may be troublesome due to the substrate competition. Addition of sulphuric acid when inoculum cells are washed can control the bacterial growth or alternatively biocides are used. This work aimed to verify the effect of chlorine dioxide, a well-known biocide for bacterial decontamination of water and equipments, against contaminant bacteria ( Bacillus subtilis, Lactobacillus plantarum, Lactobacillus fermentum and Leuconostoc mesenteroides) from alcoholic fermentation, through the method of minimum inhibitory concentration ( MIC), as well as its effect on the industrial yeast inoculum. Lower MIC was found for B. subtilis ( 10 ppm) and Leuconostoc mesenteroides ( 50 ppm) than for Lactobacillus fermentum ( 75 ppm) and Lactobacillus plantarum ( 125 ppm). Additionally, these concentrations of chlorine dioxide had similar effects on bacteria as 3 ppm of Kamoran (R) ( recommended dosage for fermentation tanks), exception for B. subtilis, which could not be controlled at this Kamoran (R) dosage. The growth of industrial yeasts was affected when the concentration of chlorine dioxide was higher than 50 ppm, but the effect was slightly dependent on the type of yeast strain. Smooth yeast colonies ( dispersed cells) seemed to be more sensitive than wrinkled yeast colonies ( clustered cells/pseudohyphal growth), both isolated from an alcohol-producing unit during the 2006/2007 sugar cane harvest. The main advantage in the usage of chlorine dioxide that it can replace antibiotics, avoiding the selection of resistant populations of microorganisms.

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Acid erosion is a superficial loss of enamel caused by chemical processes that do not involve bacteria. Intrinsic and extrinsic factors, such as the presence of acid substances in the oral cavity, may cause a pH reduction, thus potentially increasing acid erosion. The aim of this study was to evaluate the microhardness of bleached and unbleached bovine enamel after immersion in a soda beverage, artificial powder juice and hydrochloric acid. The results obtained for the variables of exposure time, acid solution and substrate condition (bleached or unbleached enamel) were statistically analyzed by the ANOVA and Tukey tests. It was concluded that a decrease in microhardness renders dental structures more susceptible to erosion and mineral loss, and that teeth left unbleached show higher values of microhardness compared to bleached teeth.

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From the hexane-soluble fraction of an ethanol extract from leaves and stems of Stemodia foliosa (Scrophulariaceae), the new stearic acid 4-[(n-pentoxy)phenethyl] ester (1) was isolated. This compound exhibited antibacterial properties at 10μg/mL concentration by using disc diffusion method against Gram-positive bacteria Bacillus cereus and Bacillus subtilis and fast-acid bacterium Mycobacterium fortuitum. The structure of the new compound was elucidated by spectroscopic methods and by chemical conversion.

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This study evaluated the antibacterial activity of the glass-ionomer cements Vitrebond (3M ESPE), Ketac Molar (3M ESPE) and Fuji IX (GC America) against S mutans, S sobrinus, L acidophilus and A viscosus, using the agar diffusion test. Inocula were obtained by the seed of indicators cultures in BHI broth incubated at 37°C for 24 hours. Base layers containing 15 mL of BHI agar and 300 μL of each bacteria suspension were prepared in Petri dishes. Six wells measuring 4 mm in diameter were made in each plate and completely filled with one of the testing materials. A 0.2% chlorhexidine solution applied in round filter papers was used as control. Tests were performed 12 times for each material and bacteria strain. After incubation of the plates at 37°C for 24 hours, the zones of bacterial growth inhibition around the wells were measured. Overall, the results showed the following sequence of antibacterial activity: Vitrebond (despite the activation mode) > 0.2% chlorhexidine > Ketac Molar > Fuji IX, according to Kruskal-Wallis and Mann-Whitney statistical tests. This study confirmed significant antibacterial activity for two conventional glass-ionomers and one resin-modified glass-ionomer material. The resin-modified glass-ionomer cement Vitrebond, regardless of the activation mode, presented the best antibacterial activity against S mutans and S sobrinus. The antibacterial activity against A viscosus for Vitrebond was similar to 0.2% chlorhexidine, while light activation reduced its antibacterial activity against L acidophilus. ©Operative Dentistry, 2005.