Evolution signatures in genome network properties

Genomes maybe organized as networks where protein-protein association plays the role of network links. The resulting networks are far from being random and their topological properties are a consequence of the underlying mechanisms for genome evolution. Considering data on protein-protein association networks from STRING database, we present experimental evidence that degree distribution is not scale free, presenting an increased probability for high degree nodes. We also show that the degree distribution approaches a scale invariant state as the number of genes in the network increases, although real genomes still present finite size effects. Based on the experimental evidence unveiled by these data analyses, we propose a simulation model for genome evolution, where genes in a network are either acquired de novo using a preferential attachment rule, or duplicated, with a duplication probability that linearly grows with gene degree and decreases with its clustering coefficient. The results show that topological distributions are better described than in previous genome evolution models. This model correctly predicts that, in order to produce protein-protein association networks with number of links and number of nodes in the observed range, it is necessary 90% of gene duplication and 10% of de novo gene acquisition. If this scenario is true, it implies a universal mechanism for genome evolution

Composição indutora de obesidade em ratos e uso da composição para o preparo de uma composição para induzir obesidade em ratos

Universidade Federal do Rio Grande do SulCiências Básicas da SaúdeDepositad

RAGE against the glycation machine in synucleinopathies : time to explore new questions

Oligomerization and aggregation of misfolded forms of α-synuclein are believed to be key molecular mechanisms in Parkinson’s disease (PD) and other synucleinopathies, so extensive research has attempted to understand these processes. Among diverse post-translational modifications that impact α-synuclein aggregation, glycation may take place at several lysine sites and modify α-synuclein oligomerization, toxicity, and clearance. The receptor for advanced glycation end products (RAGE) is considered a key regulator of chronic neuroinflammation through microglial activation in response to advanced glycation end products, such as carboxy-ethyl-lysine, or carboxy-methyl-lysine. The presence of RAGE in the midbrain of PD patients has been reported in the last decades and this receptor was proposed to have a role in sustaining PD neuroinflammation. However, different PD animal models demonstrated that RAGE is preferentially expressed in neurons and astrocytes, while recent evidence demonstrated that fibrillar, non-glycated α-synuclein binds to RAGE. Here, we summarize the available data on α-synuclein glycation and RAGE in the context of PD, and discuss about the questions yet to be answered that may increase our understanding of the molecular bases of PD and synucleinopathies

Comparison of the effects of two antioxidant diets on oxidative stress markers in triathletes

Intense exercise generates an imbalance in the redox system. However, chronic exercise can yield antioxidant adaptations. A few studies with humans have investigated the effects of antioxidant diets on athletes. Therefore we compared the effects of two dietary interventions on oxidative stress in competitive triathletes. Thirteen male triathletes were selected and divided into 2 groups: one that had a regular antioxidant diet (RE-diet) and the other that had a high antioxidant diet (AO-diet). The diet period was 14 days and blood samples were collected before and after this period. The AO-diet provided twice the dietary reference intake (DRI) of α-tocopherol (30 mg), five times the DRI of ascorbic acid (450 mg), and twice the DRI of vitamin A (1800 g), while the RE-diet provided the DRI of α-tocopherol (15 mg), twice the DRI of ascorbic acid (180 mg) and the DRI of vitamin A (900 μg). The oxidative stress parameters evaluated were: thiobarbituric acid reactive substances (TBARS), total reactive antioxidant potential (TRAP), total sulfhydryl, carbonyl, superoxide dismutase (SOD) activity, hydrogen peroxide consumption and glutathione peroxidase (GPx) activity. We observed, after the diet period, an increase in sulfhydryl, TRAP, TBARS and SOD activity, and a decrease in carbonyl levels. However, no changes were found in hydrogen peroxide consumption or GPx activity. We concluded that antioxidant-enriched diets can improve the redox status of triathletes

Enhancement of Mechanical Properties of Aluminum and 2124 Aluminum Alloy by the Addition of Quasicrystalline Phases

A structural and mechanical characterization of pure aluminum and 2124 T6 aluminum alloy reinforced with quasicrystalline phases of composition Al65Cu20Fe15 and Al70.5Pd21Mn8.5 (% at.) were performed. The quasicrystalline phases were synthesized by arc melting and then milled to produce powder of the alloys, which were then mechanical mixed with the starting powders of aluminum and 2124 aluminum alloy. The composites were produced by hot extrusion of a mechanical mixture containing 20% (% wt.) of the reinforcing phases on the metallic matrix. The structural characterization of the composites was carried out by X- ray diffraction, scanning electron microscopy and transmission electron microscopy. Mechanical characterization was carried out by Vickers hardness measurements and torsion tests at room temperature. The pure aluminum/ quasicrystal composite showed the presence of the same phases from the starting powder mixture while for the 2124 aluminum alloy/Al65Cu20Fe15 the quasicrystalline phase transformed to the tetragonal w-Al7Cu2 Fe during the solution heat treatment. Mechanical strength of the composites presented a substantial increase in comparison to the original matrix metal. While the equivalent ultimate tensile strength of the Al/ quasicrystal composites reached values up to 215MPa and Vickers hardness up to 60HV, the 2124/ quasicrystal composites reached values up to 670MPa and Vickers hardness up to 190HV.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fed Univ Sao Carlos UFSCAR, Grad Program Mat Sci & Engn, Rod Washington Luiz,Km 235, BR-13565905 Sao Carlos, SP, BrazilState Univ Rio de Janeiro UERJ, Polytech Inst, R Bonfim 25, BR-28625570 Nova Friburgo, RJ, BrazilFed Univ Sao Paulo UNIFESP, Sci & Technol Inst, R Talim 330, BR-12231280 Sao Jose Dos Campos, SP, BrazilFed Univ Sao Carlos UFSCAR, Dept Mat Engn, Rod Washington Luiz,Km 235, BR-13565905 Sao Carlos, SP, BrazilScience and Technology Institute, Universidade Federal de São Paulo (UNIFESP), R. Talim 330, 12231-280, São José dos Campos, SP, BrazilFAPESP: 2011/06497-9Web of Scienc

Inosina extracelular protege células de Sertoli contra a ação do peróxido de hidrogênio

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Tratamento com N-acetilcisteína e deferroxiamina protege contra estresse oxidativo e aumenta sobrevida na sepse em ratos

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