SIRT1 Deacetylase Activity and the Maintenance of Protein Homeostasis in Response to Stress: An Overview

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

HDAC inhibition decreases XIST expression on female IVP bovine blastocysts

During initial development, both X chromosomes are active in females, and one of them must be silenced at the appropriate time in order to dosage compensate their gene expression levels to male counterparts. Silencing involves epigenetic mechanisms, including histone deacetylation. Major X chromosome inactivation (XCI) in bovine occurs between hatching and implantation, although in vitro culture conditions might disrupt the silencing process, increasing or decreasing X-linked gene expression. In this study, we aimed to address the roles of histone deacetylase inhibition by trichostatin A (TSA) on female preimplantation development.We tested the hypothesis that by enhancing histone acetylation, TSA would increase the percentage of embryos achieving 16-cell stage, reducing percentage of embryos blocked at 8-cell stage, and interfere with XCI in IVF embryos. We noticed that after TSA treatment, acetylation levels in individual blastomeres of 8-16 cell embryos were increased twofold on treated embryos, and the samewas detected for blastocysts. Changes among blastomere levels within the same embryo were diminished on TSA group, as low-acetylated blastomeres were no longer detected. The percentage of embryos that reached the 5th cleavage cycle 118 h after IVF, analyzed by Hoechst staining, remained unaltered after TSA treatment. Then, we assessed XIST and G6PD expression in individual female bovine blastocysts by quantitative real-time PCR. Even though G6PD expression remained unaltered after TSA exposure, XIST expression was eightfold decreased, and we also detected a major decrease in the percentage of blastocysts expressing detectable XIST levels after TSA treatment. Based on these results, we conclude that HDAC is involved on XCI process in bovine embryos, and its inhibition might delay X chromosome silencing and attenuate aberrant XIST expression described for IVF embryos. © 2013 Society for Reproduction and Fertility.

Ácido cítrico e quitosana na conservação pós-colheita de lichias ‘Bengal’

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Síntese, caracterização e atividade antifúngica de derivados anfifílicos de dietilaminoetil-quitosana contra Aspergillus flavus e Aspergillus parasiticus

Pós-graduação em Química - IBILCE

Estudo e transformação química de biopolímeros a base de quitina e quitosana para preparação de materiais com diversas propriedades

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ácido cítrico e quitosana na conservação de lichias 'Bengal'

The aim of this study was to evaluate citric acid application with or without chitosan on the maintenance of the quality of litchi 'Bengal'. It was used litchi on mature maturation stage. After selection, fruits were immersed for one minute on the solution of citric acid and chitosan: [1]Control - without immersion; [2] citric acid 300g L-1, [3] citric acid 300 g L-1 + chitosan 0,3%, [4]citric acid 300 g L-1 + chitosan 0,6%, [5] citric acid 600 g L-1, [6] citric acid 600 g L-1 + chitosan 0,3%, [7] citric acid 600 g L-1 + chitosan 0,6%. Chitosan of low molecular weight and deacetylation degree of 75,58% (Sigma - Aldrich®) were used. After immersion, fruits were put to drain the excess of solution. Then, they were stored in cool chamber at 5ºC, previously sanitized, for 20 days. The experiment was conducted following a completely randomized design, with a factorial scheme composed by seven coating solutions and five sampling dates. Every five days were evaluated: loss of fresh mass of fruits; color; content of anthocyanins and the activity of peel enzymes polyphenoloxidase and peroxidase. It was verified that the solution of citric acid 600 g L-1, associated or not to chitosan, and the combination of chitosan 0,3% to 300 g L-1 of citric acid were the most efficient to maintain the quality of litchi 'Bengal' for 20 days at 5ºC.

Síntese e caracterização de copolímeros de polietilenoglicol monometil éter em quitosana cationizada para futuras aplicações em biotecnologia

Pós-graduação em Química - IQ

Estudo físico-químico da atividade fungicida de derivados anfifílicos de quitosana contra fungos do gênero Aspergillus : interação com modelos de membranas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)