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- The Action of Polyphenols in Diabetes Mellitus and Alzheimer's Disease: A Common Agent for Overlapping PathologiesPublication . Silveira, Ana C.; Dias, Jane; Santos, Vanessa M.; Oliveira, P.F.; Alves, Marco G; Rato, Luís; Silva, Branca M.Diabetes Mellitus (DM) and Alzheimer's disease (AD) are two prevalent diseases in modern societies, which are caused mainly by current lifestyle, aging and genetic alterations. It has already been demonstrated that these two diseases are associated, since individuals suffering from DM are prone to develop AD. Conversely, it is also known that individuals with AD are more susceptible to DM, namely type 2 diabetes (T2DM). Therefore, these two pathologies, although completely different in terms of symptomatology, end up sharing several mechanisms at the molecular level, with the most obvious being the increase of oxidative stress and inflammation. Polyphenols are natural compounds widely spread in fruits and vegetables whose dietary intake has been considered inversely proportional to the incidence of DM and AD. So, it is believed that this group of phytochemicals may have preventive and therapeutic potential, not only by reducing the risk and delaying the development of these pathologies, but also by improving brain's metabolic profile and cognitive function. The aim of this review is to understand the extent to which DM and AD are related pathologies, the degree of similarity and the relationship between them, to detail the molecular mechanisms by which polyphenols may exert a protective effect, such as antioxidant and anti-inflammatory effects, and highlight possible advantages of their use as common preventive and therapeutic alternatives.
- Biosynthesis of small noncoding RNAs in Rhodovulum sulfidophilumPublication . Dias, Jane Risete Pires dos Santos; Passarinha, Luís António Paulino; Sousa, Fani Pereira deBiosynthesis of noncoding RNAs (ncRNAs) in microorganisms has stood out as a cost-effective and favourable method for natural RNA production, and Rhodovulum sulfidophilum (R. sulfidophilum), a marine phototrophic bacterium, has been studied as a potential host for this bioprocess. Then, this work intends to optimize, in a mini bioreactor platform, the fermentation process of R. sulfidophilum strain DSM 1374 as a recombinant host to produce ncRNAs. So, the effect of the inoculum size, temperature and oxygen availability was studied, and the best outcome was achieved in fermentations at 30 ºC with 18% inoculum where fully aerobic-dark conditions are provided. Under such conditions the effects of the main carbon source were analysed in which glucose (Si = 10 g/L) was replaced by glycerol in R. sulfidophilum fermentation. Glycerol metabolization was analysed when using differents initial concentrations (Si = 20, 10, 5, and 2.5 g/L) and the consumption of both the carbon sources was assessed by HPLC-RID. Briefly, the optimized conditions in bioreactor scale yielded 1.8 times more biomass when glycerol (Si = 10 g/L) was the main carbon source, and 2.3 times more biomass compared to the optimized conditions in shake flask scale. Both carbon source lead to a maximum of total RNA production at 60 h, being of 537 ± 49 µg/mL in glucose and 446 ± 58 µg/mL in glycerol. Noteworthy, the electrophoretic qualitative analysis of small ncRNAs biosynthesis demonstrated a higher concentration also at 60 h in both glucose and glycerol fermentation. The results from the batch fermentations suggest a more efficient utilization of glycerol by R. sulfidophilum which reflects in higher biomass and reasonably higher ncRNA productivity. With a view of increasing the overall biomass and productivity, fed-batch experiments were carried out through constant glycerol feed. The results proved that a feed solution containing only glycerol does not lead to biomass increasing, as is expected, highlighting the interaction of different growth limiting factors. All these results together leave an open door for the study of glycerol as a substrate for recombinant biosynthesis of ncRNAs in R. sulfidophilum, specifically for the development of new feed strategies adequate to the nutritional requirements of the bacteria and that allow increasing the biomass and the productivity of ncRNAs.