Lérida Liss Flores Villavicencio

Human Lung Cancer Cell Line A-549 ATCC Is Differentially Affected by Supranutritional Organic and Inorganic Selenium

The effects of organic and inorganic forms of selenium (Se) on human cells have been extensively studied for nutritional concentrations; however, to date, little is known about the potential toxicity at supranutritional levels. In the present study we determined the effects of sodium selenite (SSe) and selenomethionine (SeMet) on cell growth and intracellular structures in lung cancer cells exposed at Se concentrations between 0 and 3 mM. Our results showed that SSe affected cell growth more rapidly than SeMet (24 h and 48 h, resp.). After 24 h of cells exposure to 0.5, 1.5, and 3 mM SSe, cell growth was reduced by 10, 50, and 60%, as compared to controls. After 48 h, nuclear fragmentation was evident in cells exposed to SSe, suggesting an induction to cell death. In contrast, SeMet did not affect cell proliferation, and the cells were phenotypically similar to controls. Microtubules and microfilaments structures were also affected by both Se compounds, again SSe being more toxic than SeMet. To our knowledge, this is the first report on the differential effects of organic and inorganic Se in supranutritional levels in lung cancer cells.

Extracts from Flammulina velutipes Inhibit the Adhesion of Pathogenic Fungi to Epithelial Cells.

Background: Recently, extracts from natural sources have been tested for their antifungal properties. In this aspect, Flammulina velutipes extracts possess a significant amount of branch-chained carbohydrates with mannose moieties that, hypothetically, can reduce the adhesion. Objective: In this study, we assessed the capacity of extracts from F. velutipes (wild-type AQF-1 and ATCC 34574 as the reference strain) to inhibit the adhesion of S. schenkii and C. albicans to epithelial cells. Materials and Methods: The aqueous extracts from F. velutipes strains were obtained by sonication, total carbohydrate and protein was analyzed by Dubois and Lowry methods respectively. Effect of the extracts (50, 100 and 150 μg/mL) on the fungi adhesion to host cells was evaluated after 1 h interaction, and the percentage of inhibition of adhesion was measured. After of interaction the cytoskeleton from cell was analyzed with phalloidin-FITC. Results: The extract from strain AQF-1 (50, 100 and 150 μg/mL) inhibited the adhesion of: S. schenkii in a dose-dependent manner (4.9, 7.5 and 12.7%, respectively) and C. albicans in a dose-independent manner (5.2%). The percentage of inhibition by extracts from the strain ATCC34574 at the same concentrations, shown that are dose independent for both fungi: 3.9% for S. schenkii and 2.6% for C. albicans. Conclusion: The extracts from F. velutipes inhibit the adhesion of pathogenic fungi to host cells. The mechanism molecular is unknown; however, is probably an interaction between the polysaccharides from extracts with the fungi receptors. This aspect is currently analyzed.

Proteases of "Sporothrix schenckii": Cytopathological effects on a host-cell model

BACKGROUND Sporotrichosis is a fungal infection caused by the Sporothrix schenckii complex. The adhesion of the fungus to the host tissue has been considered the key step in the colonization and invasion, but little is known about the early events in the host-parasite interaction. AIMS To evaluate the proteolytic activity of S. schenckii on epithelial cells. METHODS The proteolytic system (at pH 5 and 7) was evaluated using azocoll and zymograms. The host-parasite interaction and epithelial cell response were also analyzed by examining the microfilament cytoskeleton using phalloidin-FITC and transmission electron microscopy. Finally, the metabolic activity was determined using an XTT assay. RESULTS The zymograms showed that S. schenckii yeast cells possess high intracellular and extracellular proteolytic activities (Mr≥200, 116, 97, and 70kDa) that are pH dependent and are inhibited by PMSF and E64, which act on serine and cysteine-type proteases. During the epithelial cell-protease interaction, the cells showed alterations in the microfilament distribution, as well as in the plasma membrane structure. Moreover, the metabolic activity of the epithelial cells decreased 60% without a protease inhibitor. CONCLUSIONS Our data demonstrate the complexity of the cellular responses during the infection process. This process is somehow counteracted by the action of proteases inhibitors. Furthermore, the results provide critical information for understanding the nature of host-fungus interactions and for searching a new effective antifungal therapy, which includes protease inhibitors.

Activity of Extracts from Submerged Cultured Mycelium of Winter Mushroom, Flammulina velutipes (Agaricomycetes), on the Immune System In Vitro

Extracts from submerged cultured mycelium of two strains of Flammulina velutipes, a popular culinary mushroom, were obtained by ultrasound and tested in vitro to determine their activity in innate immunity (monocytes/ macrophages). In addition, polyclonal antibodies against the extracts were produced. Both extracts have similar glycoproteins that contain mannose and glucose but have different glycoproteins with galactoseamine units. Two novel immunogenic glycoproteins with molecular weights of 32 and 25 kDa have been revealed. It is thought that these proteins are produced only by submerged cultured mycelium. Both extracts show immune-enhancing activity based on the significant modification of various parameters such as cytokine production, phagocytosis, and reactive oxygen species production.