RENATO ARAÚJO PRATES
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Resumo IPEN-doc 23233 Incorporation of the methylene blue photosensitizer in the presence of glucose in strains of candida albicans with multidrug efflux systems2017 - SILVA, TAMIRES; ALVARENGA, LETICIA; LEAL, CINTIA; MIRANDA, BIANCA G.; SUZUKI, LUIZ C.; KATO, ILKA; RIBEIRO, MARTHA; PAVANI, CHRISTIANE; PRATES, RENATOBackground: Infectious diseases are responsible for 60% of deaths in developing countries.Candida albicans cause severe infection in immunocompromised patients and the commonly used treatments have not been effective against microbial resistance. Photodynamic therapy (PDT) is a new promising strategy to microbial inactivation based on the use of photosensitizer (PS) in the presence of oxygen and activation by light to form reactive oxygen species.C.albicanshas glucose sensors which could facilitate the entrance of the PS. The objective of this study was to evaluate the role of glucose in the photodynamic inactivation of C. albicans. Study: C. albicans ATCC 10231, YEM 12, YEM 13, YEM 14, and YEM15were aerobically grown on Sabouraud agar and incubated at 308C for 24 hours. Microbial inoculants were divided into 4 groups with and without glucose: Control; Only irradiation; PS toxicity and PDT groups with three irradiation times.After going throughthe treatments, the colony-forming units were counted and the data were subjected to statistical analysis (ANOVA) and Tukey test. To measure the concentration ofMB, fluorescence spectroscopy and flow cytometry were used. Results: We observed that yeast with overexpression of Major Facilitator Superfamily membrane pore tend to accumulate more MB in its cytoplasm, whereas strains that overexpress ABC pumps demonstrated the greater survival against the photodynamic challenge. Conclusion: PDT is an efficient strategy against C. albicans and the presence of glucose can intervene in the photodynamic effect. The presence of MB in the intracellular region of the yeast predisposes to greater photodynamic inactivation, however, its germicidal capacity is related to the type and characteristics of the microbial.Resumo IPEN-doc 23128 Application of photodynamic therapy with led and methylene blue in streptococcus mutans in the presence of glucose- in vitro study2017 - LEAL, CINTIA; ALVARENGA, LETICIA; SILVA, TAMIRES; BUSSADORI, SANDRA; KATO, ILKA; RIBEIRO, MARTHA; PRATES, RENATOBackground: Streptococcus mutans is a microorganism associated with tooth decay; many genes that express adhesion, biofilm formation, extracellular polysaccharide, carbohydrate uptake and acid tolerance regulate its cariogenic properties. S. mutans inhabits a complex biofilm and it produces a large amount of exopolysaccharides to promote adhesion and enabling transport pumps. Photodynamic therapy involves the use of a photosensitizer (PS), which is absorbed by specific cells followed by irradiation with visible light, resulting in cell death. The aim of this study was to investigate antimicrobial photodynamic therapy on Streptococcus mutans in the presence of glucose. Study: Streptococcus mutans was grown in brain heart infusion (BHI) at 37 8C for 48 h. Inocula were prepared with pure colonies, which were suspended in phosphate buffered saline (PBS) with and without 50mM glucose. One-hundred micromolar methylene blue was used as photosensitizer and the experiments were performed with groups (control, irradiated with LED, FS without irradiation, and PDT 30, 60, and 120 s). Colony form units were counted and statistically analyzed (oneway ANOVA and Tukey 5%). Results: The irradiation as well as the photosensitizer in the dark did not cause cell death. In contrast, in experiments without glucose, PDT caused cell death proportional the amount of light used. The more light, the higher the inactivation of S. mutans and after 2 min a reduction of 7 orders of magnitude (100%) was observed. In experiments with glucose cell death was observed even increasing the radiant exposure. Conclusion: We concluded that PDT is a viable solution for inactivation of S. mutans in suspension, and that the presence of glucose activates efflux pumps in the bacterial cell wall, and it drastically reduces the effect of PDT.Resumo IPEN-doc 22393 In vitro effect photodynamic therapy with LED and methylene blue on Candida albicans pretreated with glucose2016 - SILVA, TAMIRES O.; SUZUKI, LUIS; KATO, ILKA; DEANA, ALESSANDRO; RIBEIRO, MARTHA; PRATES, RENATOResumo IPEN-doc 22394 Ultrastructural changes following antimicrobial photodynamic therapy on Candida albicans2016 - PRATES, RENATO; SANTOS, CAMILA; ARANHA CHAVES, VICTOR; RIBEIRO, MARTHA; KATO, ILKA