Browsing by Issue Date, starting with "2018-09-27"
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- Bacteriocin production of the probiotic Lactobacillus acidophilus KS400Publication . Gaspar, C; Donders, Gilbert; Oliveira, Rita Palmeira de; Queiroz, João; Tomaz, C. T.; Oliveira, J. Martinez de; Oliveira, Ana Palmeira deIn the last years, the use of probiotics, including Lactobacillus species, has received much attention to prevent and treat vaginal disorders. These species have been described as having the ability to colonize the epithelial surface and produce antimicrobial metabolites that are able to control the remaining vaginal microflora. This study aimed to identify and characterize, for the first time, a bacteriocin natively produced by Lactobacillus acidophilus KS400 (probiotic strain from Gynoflor®-Medinova AG, Switzerland) and its antimicrobial activity against relevant urogenital pathogens. After organic acids and hydrogen peroxide neutralization in the fermented Lactobacillus acidophilus KS400 culture medium, bacteriocin activity was tested against the indicator microorganism Lactobacillus delbrueckii ATCC9649. The fermentation of Lactobacillus acidophilus KS400 for bacteriocin production was carried out in batch mode, and its antimicrobial activity, optical density and pH were monitored. After production and extraction, the bacteriocin molecular weight was estimated by electrophoresis and tested against vaginal pathogenic microorganisms. As described for other bacteriocins, batch fermentation profiles indicated that bacteriocin production occurs during the exponential growth phase of the lactobacilli, and declines during their stationary growth phase. The molecular weight of the bacteriocin is approximately 7.5 kDa. The bacteriocin containing protein extract was shown to inhibit the growth of Gardnerella vaginalis, Streptococcus agalactiae, Pseudomonas aeruginosa and the indicator strain Lactobacillus delbrueckii ATCC9649. We conclude that L. acidophilus KS400 produces bacteriocin with antimicrobial activity against relevant urogenital pathogens.
- Web application for the analysis of assessment testsPublication . Prata, Paula; Duarte, Luís; Ferrão, Maria EugéniaIntroduction: An assessment test enables the evaluation of an individual’s competence or ability. Such tests are important for both teaching and professional training institutions, as well as for the recruiting of human resources in the enterprise. Objectives: The present paper introduces the “Evaluate” web application, for the analysis of assessment tests. Methods: The design and implementation of the application is described, which allows the management of assessment items, used to constitute evaluation tests, upon which results the main descriptive statistic values used under the classical test theory in the analysis of assessment tests are calculated. The application was developed in Python, within the Django framework, and tested with real assessment tests. Results: Scores are assigned to each assessment item, and various statistics — such as difficulty and discrimination index, point-biserial correlation, test internal consistency coefficient — can be obtained upon the answers of the subjects, as well as a graphic analysis of the performance of each subject on each assessment item, as well as on the test as a whole. Conclusion: The “Evaluate” application makes a meaningful contribution to a better knowledge of assessment tools used in competence evaluation, by allowing the detection of inconsistencies and the consequent improvement in the process.