Antarctic Strain of Rhodotorula mucilaginosa UFMGCB 18,377 Attenuates Mucositis Induced by 5-Fluorouracil in Mice.

Mucositis is one of the most strenuous side effects caused by chemotherapy drugs, such as 5-fluorouracil (5-FU), during the treatment of several types of cancers. The disease is so prevalent and aggressive that many patients cannot resist such symptoms. However, despite its frequency and clinical significance, there is no effective treatment to prevent or treat mucositis. Thus, the use of probiotics as an adjuvant for the treatment has gained prominence. In the present study, we evaluated the effectiveness of oral administration of the Antarctic strain of Rhodotorula mucilaginosa UFMGCB 18,377 as an alternative to minimize side effects of 5-FU-induced mucositis in mice. Body weight, food consumption, stool consistency, and presence of blood in the feces were assessed daily in mice orally treated or not with the yeast and submitted or not to experimental mucositis. Blood, bones, and intestinal tissues and fluid were used to determine intestinal permeability and immunological, microbiological, and histopathological parameters. Treatment with R. mucilaginosa UFMGCB 18,377 was able to decrease clinical signs of the disease, such as reduction of food intake and body weight loss, and also decreased the number of intestinal enterobacteria and intestinal length shortening. Additionally, treatment was able to decrease the levels of MPO and EPO activities and inflammatory infiltrates, as well as the histopathological lesions characteristic of mucositis in the jejunum and ileum. Results of the present study showed that the oral administration of R. mucilaginosa UFMGCB 18,377 protected mice against mucositis induced by 5-FU.

In Vitro and In Vivo Evaluation of the Probiotic Potential of Antarctic Yeasts.

Antarctica is one of the most pristine and inhospitable regions of the planet, mostly inhabited by microorganisms that survive due to unusual metabolic pathways to adapt to its extreme conditions, which could be interesting for the selection of new probiotics. The aim of the present study was to screen in vitro and in vivo putative probiotics among 254 yeasts isolated from different habitats of Antarctica. In vitro selection evaluated functional (growth at 37 °C, resistance to simulated gastric environment, and to bile salts), safety (degradation of mucin, production of ß-haemolysis and resistance to antifungal drugs), and beneficial (production of antagonistic substances and adhesion to pathogens) properties. Twelve yeasts were able to grow at 37 °C, one of which was eliminated to present ß-haemolytic ability. The remained yeasts resisted to gastric simulation and bile salts, but none presented antagonism against the pathogens tested. Because of the high co-aggregation with Salmonella enterica Typhimurium and growth yield, Rhodotorula mucilaginosa UFMGCB 18377 and Saccharomyces cerevisiae UFMGCB 11120 were selected for in vivo steps using mice challenged with S. Typhimurium. Both yeasts reached high faecal population levels when daily administered, but only R. mucilaginosa UFMGCB 18377 protected mice against Salmonella infection presenting a higher survival and reduced weight loss, bacterial translocation to the liver, sIgA intestinal levels, and intestinal and hepatic MPO and EPO activities. Our in vitro and in vivo results suggest that R. mucilaginosa UFMGCB 18377 presents probiotic potential and deserve further studies as candidate of probiotic by-products. In addition, this is the first screening study of yeasts isolated from Antarctic environments and of Rhodotorula genus for probiotic use.

Characterization of new biosurfactant produced by Trichosporon montevideense CLOA 72 isolated from dairy industry effluents.

The yeast strain CLOA 72 isolated from the effluent of a dairy industry in Brazil and identified as Trichosporon montevideense, was able to grow and produce a glycolipid biosurfactant when cultured on a mineral medium (MM) with sunflower oil as the carbon source. Biosurfactant production was partially growth-associated and maximal emulsification activity was observed at 144 h of cultivation (78.92%). The biosurfactant purified by precipitation with ethanol showed 78.66% emulsifying activity when used in concentrations above 4.5 mg/ml and was able to reduce the surface tension of water to values below 44.9 mN/m. The critical micellar concentration (CMC) was found to be 2.2 mg/ml. The highest emulsifying activity (E(24)) has been observed with vegetable oils, toluene, kerosene, isooctane, cyclohexane, hexane, diesel oil and hexadecane as compared to mineral oil and oleic acid. The biosurfactant also showed good stability during exposure to 100 degrees C for different periods of time (10 to 60 min), to high salinity (30% of NaCl, KCl and NaHCO(3)), and to a wide range of pH values (1-10). The biosurfactant purified by gel filtration chromatography is a glycolipid, with lipid portion containing 16.03% (9Z)-octadec-9-enoic acid, 14.92% hexadecanoic acid, and 9.63% (E) octadec-9-enoic acid and the carbohydrate portion containing mannose (35.29%), xylose (41.99%), arabinose (17.47%), and glucose (5.25%).