Carrera de Biotecnología

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    Determinación de la actividad antimicrobiana y antioxidante de los extractos de la planta sunfo (Clinopodium nubigenum) frente a cepas de Staphylococcus
    (Universidad Técnica de Ambato. Facultad de Ciencia e Ingeniería en Alimentos y Biotecnología. Carrera de Biotecnología, 2024-02) Chiriboga Cordones, Juan Fernando; De la Torres Olvera, Helena Maritza
    Foodsborne illnesses cause symptoms such as: diarrehea, vomiting and stomach pains; the treatment is the use of antibiotics such as: cephalosporins, penicillin and aminoglycosides. Due to the bad use, resistance has occurred to bacteria such as: E. coli, L. monocytogenes, S. aureus, among others. In the present investigation, the bacteria used was S. aureus and Coagulase Negative Staphylococcus (CoNS), obtained in cheeses from markets in the City of Ambato, where searched for an alternative to the use of antibiotics through antimicrobial tests and its relationship with the antioxidant activity. For this purpose, an extract of the Sunfo (C. nubigenum) was obtained, where its main components are polyphenols such as: flavonoids and phenolic acids. Through the Soxhlet method, secondary metabolites were obtained together with the solvent ethanol. The identification of the bacteria was realized on Salted Mannitol Agar, a yellow colour indicated the presence of S. aureus and a red colour indicated the presence of CoNS. For the antimicrobial test, the Minimum Inhibitory Concentration (MIC) and Bactericidal Concentration (MBC) were used together with the resazurin indicator, observing a change in coloration; for antioxidant activity, a colorimetric assay was realized with 2,2-diphenyl-1-picrylhydrazyl (DPPH). Finally, it was determined that the C. nubigenum extract presented antimicrobial properties, due to the inhibition of the S. aureus and CoNS species, verifying the colour change with the MIC and MBC test. Likewise, the evaluated extract presented antioxidant properties by reading absorbances between DPPH and the extract.
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    Estandarización del método PMAxxTM qPCR para la cuantificación de la carga viable de Salmonella spp. en contenido cecal de origen avícola
    (Universidad Técnica de Ambato. Facultad de Ciencia e Ingeniería en Alimentos y Biotecnología. Carrera de Biotecnología, 2022-03) Corrales Martínez, Joselyn Griselda; Calero Cáceres, William Ricardo
    Currently, the standardization and validation of quantitative molecular techniques such as qPCR are important for the quality assurance and research sectors. Especially, the standardization of qPCR protocols for the detection of Salmonella spp. is essential, due to the impact it has on the health of the population. The present work aimed to standardize the PMAxxTM-based qPCR method for the detection and quantification of viable cells of S. infantis in poultry cecal content samples. First, staining with PMAxx bacterial viability stain (Trademark) of pure Salmonella culture samples was performed to inhibit the signal of non-viable cells. After DNA extraction with two different kits, a bank of serial dilutions was made, which were used for the construction of standard curves using the Illumina Eco Thermal Cycler (Trademark) Real-Time PCR System. In the analysis of the results, the concentration and volume of dye used significantly inhibited the signal of dead cells. The standard curves obtained with the two DNA extraction kits showed a high linearity greater than 0.99 and a limit of quantification of Ct 31.4. However, the best efficiency was obtained with the QIAamp Fast DNA Stool Mini Kit, which was 84.99 percent. Therefore, the optimization of the method obtained with this kit was used because it had acceptable yield values for the subsequent quantification of S. infantis in samples of poultry cecal contents.