Putative oncogenic viruses : some data on Brazilian subjects

The concepts of cancer etiology have changed over the years, mainly based on molecular epidemiology studies and bioinformatics approaches. Until relatively recently, the most accepted theory of cancer etiology has dealt with the accumulation of gene mutations and the consequent cognate proteins dysfunction, but now some authors have argued against the proposed theory. The additional role of noncellular genes in the cause of malignancy, associated to environmental factors and host genetic background, has been proposed and mostly accepted by the scientific community. Some of our data from human populations in Brazil concerning cancer epidemiology, molecular and serological surveys, were conducted looking for the detection of putative oncogenic viruses, as the Human T-cell Lymphotropic virus/HTLV-1/2, Human Papillomavirus/HPV, the Mouse or Human Mammary Tumor Virus/MMTV, the Human Endogenous Retrovirus/HERVs and the Hepatitis C virus/HCV, in healthy and malignized human tissues. Generally, research work around the world suggests that 10 to 20 % of all human cancers are etiologically linked to oncogenic viruses, so if the presence of exogenous or endogenous virus sequences in the human DNA has any significancy in the cancer etiology, it deserves further and continuous research work and discussion, always taking in account the human populations in their interacting surrounding environment

Suppression of a BAHD acyltransferase decreases p‐coumaroyl on arabinoxylan and improves biomass digestibility in the model grass Setaria viridis

Grass cell walls have hydroxycinnamic acids attached to arabinosyl residues of arabinoxylan (AX), and certain BAHD acyltransferases are involved in their addition. In this study, we characterized one of these BAHD genes in the cell wall of the model grass Setaria viridis. RNAi silenced lines of S. viridis (SvBAHD05) presented a decrease of up to 42% of ester-linked p-coumarate (pCA) and 50% of pCA-arabinofuranosyl, across three generations. Biomass from SvBAHD05 silenced plants exhibited up to 32% increase in biomass saccharification after acid pre-treatment, with no change in total lignin. Molecular dynamics simulations suggested that SvBAHD05 is a p-coumaroyl coenzyme A transferase (PAT) mainly involved in the addition of pCA to the arabinofuranosyl residues of AX in Setaria. Thus, our results provide evidence of p-coumaroylation of AX promoted by SvBAHD05 acyltransferase in the cell wall of the model grass S. viridis. Furthermore, SvBAHD05 is a promising biotechnological target to engineer crops for improved biomass digestibility for biofuels, biorefineries and animal feeding