Lignin biodegradation and ligninolytic enzyme studies during biopulping of Acacia Mangium wood chips by tropical white rot fungi

Abstract White rot fungi are good lignin degraders and have the potential to be used in industry. In the present work, Phellinus sp., Daedalea sp., Trametes versicolor and Pycnoporus coccineus were selected due to their relatively high ligninolytic enzyme activity, and grown on Acacia mangium wood chips under solid state fermentation. Results obtained showed that manganese peroxidase produced is far more compared to lignin peroxidase, suggesting that MnP might be the predominating enzymes causing lignin degradation in Acacia mangium wood chips. Cellulase enzyme assays showed that no significant cellulase activity was detected in the enzyme preparation of T. versicolor and Phellinus sp. This low cellulolytic activity further suggests that these two white rot strains are of more interest in lignin degradation. The results on lignin losses showed 20–30% of lignin breakdown at 60 days of biodegradation. The highest lignin loss was found in Acacia mangium biotreated with T. versicolor after 60 days and recorded 26.9%, corresponding to the percentage of their wood weight loss recorded followed by P. coccineus. In general, lignin degradation was only significant from 20 days onwards. The overall percentage of lignin weight loss was within the range of 1.02–26.90% over the biodegradation periods. Microscopic observations conducted using scanning electron microscope showed that T. versicolor, P. coccineus, Daedalea sp. and Phellinus sp. had caused lignin degradation in Acacia mangium wood chips

High-density lipoprotein attenuates secretion and gene expression of cellular adhesion molecules and proinflammatory cytokines in lipopolysaccharide-stimulated endothelial cells

This study was conducted to investigate the effects of high-density lipoprotein (HDL) onsecretion and gene expression of intercellular adhesion molecules-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), endothelial-leukocyte adhesion molecule-1 (E-selectin), interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) by human vascular endothelial cells (HUVEC). Lipoploysacharides-stimulated HUVEC was incubated with different concentrations of HDL (20-120 mg/dL) for 16 hours. The levels of all biomarkers were measured by ELISA. Total RNA was extracted and all bioamarkers’ mRNA levels were measured by Taqman real-time polymerase chain reaction assay. Different HDL concentrations reduced the secretion and expressonof all biomarkers except VCAM-1, which may contribute to the prevention and regression of atherosclerosis.Keywords: HDL; adhesion molecules; cytokines; endothelial cells; lipopolysaccharides

Antioxidant activity of high-density lipoprotein (HDL) using different in vitro assays

The role of HDL in reverse cholesterol transport is well known but other atheroprotectivemechanism, e.g. antioxidant capacities of HDL is not clear. The aim of this study is todetermine the effects of different doses of HDL on antioxidant activities assay. HDL wasisolated from plasma by single step-ultracentrifugation. The antioxidant activity of differentdoses of HDL were measured by ferric thiocyanate (FTC), 2,2-diphenyl-1-picrylhydrazyl(DPPH) and dichlorofluorescein (DCF) tests. Coincubation of HDL with LDL showed longerlag time and lower reaction rate in a dose-dependent manner compared to LDL alone (p<0.05). HDL had inhibitory effects on radical oxygen species (ROS) production but did not exhibit free radical scavenging activities. HDL is a potent antioxidant in terms of inhibition of lipid peroxidation, ROS production and LDL oxidation. These may to some extent add to theantiatherogenic beyond reverse-cholesterol transport properties of HDL.Keywords: high-density lipoprotein; reverse cholesterol transport; apolipoprotein A1;antioxidant; in vitro