The homologous and heterologous adaptation capacity of L. monocytogenes and L. innocua were determined for thyme, oregano and nutmeg essential oils, as well as their adaptation capacities to acidic stress. Minimum bactericidal concentrations (CMB) and minimum inhibitory and minimum growth pH, were established. The capacity for increased tolerance to essential oils and acidic stress, along with heterologous adaptation among the essential oils tested and to acidic pH was determined, and that between pH and essential oils. L. monocytogenes and L. innocua adapted to all essential oils and to the minimum inhibitory pH, after exposition to sub-lethal conditions. Both strains presented heterologous adaptation capacity. After previous exposition to sub-lethal essential oil concentrations, the regenerated cells were capable of growth under 3.5 pH values, and increased CMB values. Essential oil CMBs for previously cultivated cells under minimum growth pH environments also increased, attaining values 1.6 times superior to previous ones.
Determinação do pH e temperatura ótimos para a produtividade do ácido clavulânico utilizando o Streptomyces clavuligerus ATCC 27064Determination of pH and temperature optimum on the productivity of clavulanic acid using Streptomyces clavuligerus ATCC 27064Juliana Junqueira Pinelli 1 Sandra de Cássia Dias 2 Resumo: O ácido clavulânico (AC) é um metabólito secundário produzido pela bactéria GramPositiva Streptomyces clavuligerus. É um composto de suma importância, principalmente para a indústria farmacêutica, pois possui ação antibacteriana. É utilizado em associação com outros antibióticos, como a amoxicilina. Sua produção ocorre por via fermentativa. O pH e a temperatura do meio são parâmetros relevantes que podem comprometer a produção deste metabólito. O presente trabalho teve como objetivo avaliar a influência da temperatura e do pH na produção de ácido clavulânico a partir de Streptomyces clavuligerus ATCC 27064. Para isso, um número mínimo de experimentos foi desenhado com diferentes valores de pH e temperatura utilizando o planejamento experimental estatístico, delineamento composto central rotacional, DCCR, tendo como variáveis pH e temperatura e como resposta a produtividade do ácido clavulânico. Amostras foram retiradas a cada 12 horas e a produção de ácido clavulânico determinada por método espectrofotométrico. O cultivo realizado em pH 6,7 e temperatura 27ºC apresentou maior produtividade do ácido clavulânico. Palavras-chave:Delineamento composto central rotacional. Antibiótico. Metodologia de superfície de resposta. Bioprocessos Abstract: Clavulanic acid (CA) is a secondary metabolite produced by the Gram-Positive bacteria Streptomyces clavuligerus. It is a compound of great importance, mainly for the pharmaceutical industry, because it has antibacterial activity. It is used in combination with other antibiotics such as amoxicillin. Its production occurs by fermentation. The pH and temperature of the medium are relevant parameters that can compromise the production of this metabolite. The aim of this study was to evaluate the temperature and pH influence on the clavulanic acid productivity by Streptomyces clavuligerus ATCC 27064. For this, a minimum number of experiments were designed with different values of pH and temperature using statistical experimental design, central composite rotational design (CCRD) having as variables pH and temperature and as response the clavulanic acid productivity. Samples were collected every 12 hours and the clavulanic acid production was determined by spectrophotometric method. The cultivation carried out at pH 6.7 and temperature 27ºC showed the highest clavulanic acid productivity.
The objective of this work was to identify Gram-positive psychrotrophic microorganisms in expansion tanks, and to evaluate the production of enzymes and the profile of resistance to antibiotics. Samples were collected from 32 tanks using swabs and 53 isolates were selected. The presence of Bacillus, Enterococcus, Corynebacterium, Styaphylococcus, Lactococcus and Micrococcus was observed. The isolates were evaluated for enzyme production, and high proteolytic and lipolytic activity was verified. In the experiment, 12 antibiotics were used and all isolates showed multiple resistance to the tested drugs. It is concluded that good agricultural practices in milk production are essential to reduce the multiplication of these microorganisms, so that consumers can be adequately served.
The effects of additioning essential oil mixtures and reducing the sodium nitrite content (75 ppm) on Clostridium difficile inoculated in mortadellas and on the product’s technological characteristics were evaluated. 15 essential oils were tested preliminarily, but only four were selected. The minimum bactericidal concentrations found were 1.2 % for Ocimum basilicum, 0.3 % for Origanum vulgare and for Thymus vulgaris and 0.15 % for Litsea cubeba. There wasn`t significant difference in viable cell growth between treatments and the control; however, there was an increase in viable cells of approximately 2.5 log10 MPN/g after the fifth day. Combinations of oils didn`t prevent sporulation, however a synergistic effect was observed in vitro. There was a reduction in pH during storage and a greater amount of residual nitrite for the F1 treatment (Origanum vulgare (0.2 %); Thymus vulgaris (0.05 %) and Litsea cubeba (0.025 %), with 10.23 ppm, and reduction of residual nitrite during the storage period from 18.75 ppm on the first day of storage to 5.11 ppm on the last. No significant changes were observed in the technological characteristics of the product with the analyzed treatments.
Multicomponent reactions are extremely relevant in green chemistry. They offer better conditions than traditional synthesis and are, therefore, used for many organic modifications. Recently, the synthesis of polyhydroquinolines has received much attention for its high pharmacological potential. In the present study, a polyhydroquinoline derivative was synthesized without the use of catalysts or solvents. The results of nuclear magnetic resonance and infrared spectroscopy demonstrated that the molecule was successfully synthesized. The molecule presents significant results of antimicrobial activity for the bacteria tested in the serial dilution method. It also increased the clotting time by 25.66 seconds for the highest dose and 12.66 seconds for the other doses tested. Prior incubation with the dose of 125 mg reduced the thrombolytic activity to 73%. The 125, 100, and 50 mg doses previously incubated with Bothrops moojeni venom inhibited approximately 30% of the phospholipase activity. The molecule was also able to reduce the cytotoxicity induced by proteases significantly. In conclusion, the molecule presents several biological properties, which highlights its pharmaceutical potential.
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