Saccharomyces cerevisiae is a unicellular organism that during the fermentative process is exposed to a variable environment; hence, resistance to multiple stress conditions is a desirable trait. The stress caused by high hydrostatic pressure (HHP) in S. cerevisiae resembles the injuries generated by other industrial stresses. In this study, it was confirmed that gene expression pattern in response to HHP displays an oxidative stress response profile which is expanded upon hydrostatic pressure release. Actually, reactive oxygen species (ROS) concentration level increased in yeast cells exposed to HHP treatment and an incubation period at room pressure led to a decrease in intracellular ROS concentration. On the other hand, ethylic, thermic and osmotic stresses did not result in any ROS accumulation in yeast cells. Microarray analysis revealed an upregulation of genes related to methionine metabolism, appearing to be a specific cellular response to HHP, and not related to other stresses, such as heat and osmotic stresses. Next, we investigated whether enhanced oxidative stress tolerance leads to enhanced tolerance to HHP stress. Overexpression of STF2 is known to enhance tolerance to oxidative stress and we show that it also leads to enhanced tolerance to HHP stress.

Cereus jamacaru D.C. (mandacaru) is a cactus used as food and in the traditional medicine. In the present study, hydroalcoholic extract of C. jamacaru was evaluated for its chemical composition, antioxidant activity, cytotoxic and anti-cytotoxic effects in human lymphocytes and sarcoma 180 cells in vitro by MTT assay and antitumoral, mutagenic and cytotoxic effects on mice sarcoma-induced in vivo. Phytochemical characterization showed positive reactions for coumarin, flavanol and tyramine and total flavonoid content of 0.51 µg/mL. C. jamacaru showed antioxidant activity following DPPH (EC50 = 427.74 µg/mL), ABTS (EC50 = 270.57 µg/mL) and Fe2+ chelating ions assays (EC50 = 41.18 µg/mL). C. jamacaru induced significant decrease of sarcoma 180 viability at 24 h and 48 h of treatment, did not induce cytotoxicity in human lymphocytes and inhibits the cytotoxicity of cisplatin in vitro. Following in vivo assays, C. jamacaru promoted tumor reduction (86.07% of tumor inhibition), without inducing mutagenic or cytotoxic damage on mice blood cells. We propose that phenolic and alkaloid compounds in the extract are related to antioxidant activity, increasing its ability in metal chelating activity and promoting anti-cytotoxic activity against cisplatin, as well as these compounds may act on the cell cycle of the tumor cells in vitro and in vivo, leading to anticancer effects and tumor reduction.

Os centros de ciências destacam-se pelos processos interativo e dinâmico que contribuem para a construção da cultura científica. O presente trabalho visa investigar as potencialidades e desafios para o desenvolvimento de práticas educativas em um centro de ciências na cidade de Vitória, no Espírito Santo. Este estudo possui caráter exploratório e de natureza qualitativa. As evidências foram confeccionadas por meio da análise de documentos e entrevistas semiestruturadas realizadas com seis mediadores do espaço, um pedagogo e dois professores visitantes. Evidenciamos diversos desafios referentes às ações e processo formativo dos mediadores. Muitos deles centram as práticas interativas nas explicações conceituais dos instrumentos científicos. O processo formativo está centrado na partilha de experiências entre os colegas do centro e na leitura das apostilas que descrevem os instrumentos do espaço. Os professores apontam como potencialidade a possibilidade de vincular a teoria com situações práticas, relacionadas aos instrumentos científicos do espaço.

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