Annurca apple (M. pumila Miller cv Annurca) extracts act against stress and ageing in S. cerevisiae yeast cells.

BACKGROUND: During the past years, a number of studies have demonstrated the positive effect of apple on ageing and different diseases such as cancer, degenerative and cardiovascular diseases. The unicellular yeast Saccharomyces cerevisiae represents a simple eukaryotic model to study the effects of different compounds on lifespan. We previously demonstrated that apple extracts have anti-ageing effects in this organism because of their antioxidant properties. In particular, the effect is related to the presence in this fruit of polyphenols, which give a large contribution to the antioxidant activity of apples. METHODS: We we used a clonogenic assay to assess the viability and the resistance to oxidative stress of S. cerevisiae cells in the presence of Annurca apple extracts. The production of ROS and the aberrant morphology of nuclei were detected by cell staining with the fluorescent dies Dihydrorhodamine 123 and DAPI, respectively. Mitochondrial morphology was analyzed by following the localization of the mito-GFP protein into the mitochondrial matrix. RESULTS: In this study, we show that apple extracts can increase yeast lifespan, reduce the levels of reactive oxygen species and cell sensitivity to oxidative stress, and prevent nuclei and mitochondria fragmentation protecting cells from regulated cell death. CONCLUSIONS: In this paper, by using the yeast S. cerevisiae as a model, we have demonstrated that Annurca extracts possess antioxidant properties thanks to which the extracts can reduce the intracellular ROS levels and have anti-apoptotic functions thus prolonging cell lifespan. These results contribute to knowledge on the effects of natural compounds on ageing and support the use of yeast as a model organism for the development of simple tests to assess the effectiveness of bioactive substances from natural sources.

Direct interaction of Gas41 and Myc encoded by amplified genes in nervous system tumours.

In order to understand better the role of the human Tip60 complex component Gas41, we analysed its expression levels in brain tumours and searched for possible interactors. Two-hybrid screening of a human foetal brain library allowed identification of some molecular interactors of Gas41. Among them we found n-Myc transcription factor. The interaction between Gas41 and n-Myc was validated by pull-down experiments. We showed that Gas41 is able to bind both n-Myc and c-Myc proteins, and that the levels of expression of Gas41 and Myc proteins were similar to each other in such brain tumors as neuroblastomas and glioblastomas. Finally, in order to identify which region of Gas41 is involved in the interaction with Myc proteins, we analysed the ability of Gas41 to substitute for its orthologue Yaf9 in yeast; we showed that the N-terminal portions of the two proteins, containing the YEATS domains, are interchangeable, while the C-terminal portions are species-specific. In fact we found that Gas41 C-terminal portion is required for Myc protein interaction in human.