Genetic engineering of grass cell wall polysaccharides for biorefining:Engineering grass cell wall polysaccharides

Grasses represent an abundant and widespread source of lignocellulosic biomass, which has yet to fulfil its potential as a feedstock for biorefining into renewable and sustainable biofuels and commodity chemicals. The inherent recalcitrance of lignocellulosic materials to deconstruction is the most crucial limitation for the commercial viability and economic feasibility of biomass biorefining. Over the last decade, the targeted genetic engineering of grasses has become more proficient, enabling rational approaches to modify lignocellulose with the aim of making it more amenable to bioconversion. In this review, we provide an overview of transgenic strategies and targets to tailor grass cell wall polysaccharides for biorefining applications. The bioengineering efforts and opportunities summarised here rely primarily on (A) reprogramming gene regulatory networks responsible for the biosynthesis of lignocellulose, (B) remodelling the chemical structure and substitution patterns of cell wall polysaccharides and (C) expressing lignocellulose degrading and/or modifying enzymes in planta. It is anticipated that outputs from the rational engineering of grass cell wall polysaccharides by such strategies could help in realising an economically sustainable, grass-derived lignocellulose processing industry.publishersversionPeer reviewe

High-throughput Saccharification Assay for Lignocellulosic Materials

Polysaccharides that make up plant lignocellulosic biomass can be broken down to produce a range of sugars that subsequently can be used in establishing a biorefinery. These raw materials would constitute a new industrial platform, which is both sustainable and carbon neutral, to replace the current dependency on fossil fuel. The recalcitrance to deconstruction observed in lignocellulosic materials is produced by several intrinsic properties of plant cell walls. Crystalline cellulose is embedded in matrix polysaccharides such as xylans and arabinoxylans, and the whole structure is encased by the phenolic polymer lignin, that is also difficult to digest 1. In order to improve the digestibility of plant materials we need to discover the main bottlenecks for the saccharification of cell walls and also screen mutant and breeding populations to evaluate the variability in saccharification 2. These tasks require a high throughput approach and here we present an analytical platform that can perform saccharification analysis in a 96-well plate format. This platform has been developed to allow the screening of lignocellulose digestibility of large populations from varied plant species. We have scaled down the reaction volumes for gentle pretreatment, partial enzymatic hydrolysis and sugar determination, to allow large numbers to be assessed rapidly in an automated system

NGcGM3 Ganglioside: A Privileged Target for Cancer Vaccines

Active specific immunotherapy is a promising field in cancer research. N-glycolyl (NGc) gangliosides, and particularly NGcGM3, have received attention as a privileged target for cancer therapy. Many clinical trials have been performed with the anti-NGc-containing gangliosides anti-idiotype monoclonal antibody racotumomab (formerly known as 1E10) and the conjugated NGcGM3/VSSP vaccine for immunotherapy of melanoma, breast, and lung cancer. The present paper examines the role of NGc-gangliosides in tumor biology as well as the available preclinical and clinical data on these vaccine products. A brief discussion on the relevance of prioritization of cancer antigens in vaccine development is also included

Hole transport in strained SiGe-channel MOSFETs : velocity in scaled devices and mobility under applied mechanical strain

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 153-167).Since the 90 nm CMOS technology node, geometric scaling of CMOS has been supplemented with strain to boost transistor drive current. Future CMOS technology nodes (i.e. beyond the 32 nm node) will require more significant changes to continue improvements in transistor performance. Novel CMOS channel materials and device architectures are one option for enhancing carrier transport and increasing device performance. In this work strained SiGe and Ge are examined as a means of increasing the drive current in deeply scaled CMOS. As part of this work a novel high mobility strained-Ge on-insulator substrate has been developed, and the hole transport characteristics of short channel and asymmetrically strained-SiGe channel p-MOSFETs have been explored. A thin-body biaxial compressive strained-Si/strained-Ge heterostructure on-insulator (HOI) substrate has been developed, which combines the electrostatic benefits of the thin-body architecture with the transport benefits of biaxial compressive strain. A novel Germanium on Silicon growth method and a low temperature bond and etch-back process have been developed to enable Ge HOI fabrication. P-MOSFETs were also fabricated using these substrates and the hole mobility characteristics were studied. The hole mobility and velocity characteristics of short channel biaxial compressive strained-Si 45 Geo.55 p-MOSFETs on-insulator have also been examined. Devices with gate lengths down to 65 nm were fabricated. The short channel mobility characteristics were extracted and a 2.4x hole mobility enhancement relative to relaxed-Si was observed. The measured hole velocity enhancement is more modest at about 1.2x. Band structure and ballistic velocity simulations suggest that a more substantial velocity improvement can be expected with the incorporation of added longitudinal uniaxial compressive strain in the SiGe channel. The hole mobility characteristics of biaxial strained SiGe and Ge p-MOSFETs with applied uniaxial strain are also studied. The hole mobility in biaxial compressive strained SiGe is already enhanced relative to relaxed Si. It is observed that this mobility enhancement increases further with the application of longitudinal uniaxial compressive strain. Since hole mobility and velocity are correlated through their dependence on the hole effective mass, a mass driven increase in mobility with applied uniaxial strain should result in an increase in velocity. Simulations have also been performed to estimate the hole effective mass change in asymmetric strained SiGe. Finally the piezo resistance coefficients of strained SiGe are extracted and found to be larger than in Si.by Leonardo Gomez.Ph.D

Association of common variants in JAK2 gene with reduced risk of metabolic syndrome and related disorders

<p>Abstract</p> <p>Background</p> <p>Disturbances in leptin and insulin signaling pathways are related to obesity and metabolic syndrome (MS) with increased risk of diabetes and cardiovascular disease. Janus kinase 2 (JAK2) is a tyrosine kinase involved in the activation of mechanisms that mediate leptin and insulin actions. We conducted a population cross-sectional study to explore the association between two common variants in JAK2 gene and MS related traits in 724 Argentinean healthy male subjects.</p> <p>Methods</p> <p>A total of 724 unrelated men aged 37.11 ± 10.91 yr were included in a cross-sectional study. Physical examination, anthropometric measurements and biochemical analysis were determined by a standardized protocol. rs7849191 and rs3780378 were genotyped. Analyses were done separately for each SNP and followed up by haplotype analysis.</p> <p>Results</p> <p>rs7849191 and rs3780378 were both associated with reduced risk of MS [p = 0.005; OR (95%CI) = 0.52 (0.33-0.80) and p = 0.006; OR (95% CI) = 0.59 (0.40-0.86) respectively, assuming a dominant model]. rs3780378 T allele was associated with triglyceridemia values under 150 mg/dl [p = 0.007; OR (95%CI) = 0.610 (0.429-0.868)] and TT carriers showed lower triglycerides (p = 0.017), triglycerides/HDL-C ratio (p = 0.022) and lipid accumulation product (p = 0.007) compared to allele C carriers. The two-SNPs-haplotype analysis was consistent with single locus analysis.</p> <p>Conclusions</p> <p>It was found for the first time, significant associations of JAK2 common variants and related haplotypes with reduced risk of MS. These findings could be explained by the role of JAK2 in insulin and/or leptin signaling.</p

Analysis of saccharification in Brachypodium distachyon stems under mild conditions of hydrolysis

Analysis of saccharification in Brachypodium distachyon stems unde

Effects of heavy modes on vacuum stability in supersymmetric theories

We study the effects induced by heavy fields on the masses of light fields in supersymmetric theories, under the assumption that the heavy mass scale is much higher than the supersymmetry breaking scale. We show that the square-masses of light scalar fields can get two different types of significant corrections when a heavy multiplet is integrated out. The first is an indirect level-repulsion effect, which may arise from heavy chiral multiplets and is always negative. The second is a direct coupling contribution, which may arise from heavy vector multiplets and can have any sign. We then apply these results to the sGoldstino mass and study the implications for the vacuum metastability condition. We find that the correction from heavy chiral multiplets is always negative and tends to compromise vacuum metastability, whereas the contribution from heavy vector multiplets is always positive and tends on the contrary to reinforce it. These two effects are controlled respectively by Yukawa couplings and gauge charges, which mix one heavy and two light fields respectively in the superpotential and the Kahler potential. Finally we also comment on similar effects induced in soft scalar masses when the heavy multiplets couple both to the visible and the hidden sector.Comment: LaTex, 24 pages, no figures; v2 some comments and references adde

Optimization of biomass pretreatments using fractional factorial experimental design

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOPretreatments are one of the main bottlenecks for the lignocellulose conversion process and the search for cheaper and effective pretreatment methodologies for each biomass is a complex but fundamental task. Here, we used a 2ν5−1 fractional factorial des11FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO2016/13602-72016/10955-62016/05636-

Valorisation Potential of Invasive Acacia dealbata, A. longifolia and A. melanoxylon from Land Clearings

Acacia spp. are invasive in Southern Europe, and their high propagation rates produce excessive biomass, exacerbating wildfire risk. However, lignocellulosic biomass from Acacia spp. may be utilised for diverse biorefinery applications. In this study, attenuated total reflectance Fourier transform infrared spectroscopy (FTIR-ATR), high-performance anion-exchange chromatography pulsed amperometric detection (HPAEC-PAD) and lignin content determinations were used for a comparative compositional characterisation of A. dealbata, A. longifolia and A. melanoxylon. Additionally, biomass was treated with three white-rot fungi species ( Ganoderma lucidum, Pleurotus ostreatus and Trametes versicolor), which preferentially degrade lignin. Our results showed that the pre-treatments do not significantly alter neutral sugar composition while reducing lignin content. Sugar release from enzymatic saccharification was enhanced, in some cases possibly due to a synergy between white-rot fungi and mild alkali pretreatments. For example, in A. dealbata stems treated with alkali and P. ostreatus, saccharification yield was 702.3 nmol mg -1, which is higher than the samples treated only with alkali (608.1 nmol mg -1), and 2.9-fold higher than the non-pretreated controls (243.9 nmol mg -1). By characterising biomass and pretreatments, generated data creates value for unused biomass resources, contributing to the implementation of sustainable biorefining systems. In due course, the generated value will lead to economic incentives for landowners to cut back invasive Acacia spp. more frequently, thus reducing excess biomass, which exacerbates wildfire risk