Synthesis of the tetrasaccharide repeating-unit of the O-specific polysaccharide from Salmonella senftenberg

The oligosaccharide β-d-Man-(1 → 4)-α-l-Rha (1 → 3)-d-Gal-(6 ← 1)-α-d-Glc, which is the repeating unit of the O-specific polysaccharide chain of the lipopolysaccharide from Salmonella senftenberg, was obtained by glycosylation of benzyl 2,4-di-O-benzyl-6-O-(2,3,4-tri-O-benzyl-6-O-p-nitrobenzoyl-α-d-glucopyranosyl)-β-d-galactopyranoside or benzyl 2-O-acetyl-6-O-(2,3,4-tri-O-benzyl-6-O-p-nitrobenzoyl-α-d-glucopyranosyl)-β-d-galactopyranoside with 3-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-β-d-mannopyranosyl)-β-l-rhamnopyranose 1,2-(methyl orthoacetate) followed by removal of protecting groups.     

Percoll centrifugation eliminates mold contaminants from cell cultures

This work was supported by a grant and research associateship to N.A. from the Medical Research Council of Canada and the National Cancer Institute of Canada.     

Factors regulating copper uptake in free and immobilized cyanobacterium

The effect of population size, redox potential, exogenous ATP and complexing agents on Cu uptake by free and immobilized cyanobacteriumNostoc calcicola Bréb. has been studied. Cu uptake was regulated by the population size. In such comparisons, the immobilized cells had a greater longevity. Low pH conditions enhanced Cu uptake. Exogenous ATP (10 μmol/L) supplied to dark-grown free and immobilized cells did not support Cu uptake to the extent of light-grown cells. Experiments involving natural as well as synthetic complexing agents clearly established the superiority of soil extract and spent medium over EDTA (10 μmol/L), in sequestering Cu in free as well as immobilized cells.     

Changes in carbohydrates and lipids during embryonic development ofAntheraea mylitta (Lepidoptera)

Changes in carbohydrate and lipid metabolism during embryonic development inAntheraea mylitta were studied. While carbohydrates were metabolized during early embryogenesis, lipids were catabolised at the later stages. A significant increase in both total carbohydrates and glycogen on days 5 and 6 suggested the concurrent occurrence of both gluconeogenesis and glycogenesis. As the development of the embryo proceeds, both lipids and carbohydrates were utilised, resulting in the increase in the concentration of citrate, pyruvate and lactate.     

Uptake of glycollate by Skeletonema costatum (Grev.) Cleve in bacterized culture

Glycollic acid, supplied at a concentration of 1 mg l^?1, increased the relative growth rate of Skeletonema costatum (Grev.) Cleve growing in bacterized culture at limiting light intensities. There was little or no such effect at intensities approaching saturation. The presence in the medium of alumina, an adsorbent for glycollate, prolonged the lag phase, the cells remaining viable for up to 5 days. Uptake of glycollate was not appreciably affected by the bicarbonate concentration of the medium. After 3 h, 80–92% of the glycollate carbon assimilated was found in the alcohol and benzene insoluble fraction of the cells. This is in agreement with the supposition that glycollate carbon is as-similated directly by the diatom rather than after degradation by bacteria to carbon dioxide.     

Quantitative trait loci for foliar terpenes in a global eucalypt species

Terpenes are a diverse group of plant secondary metabolites that mediate a plethora of ecological interactions in many plant species. Despite increasing research into the genetic control of important adaptive traits in some plant species, the genetic control of terpenes in forest tree species is still relatively poorly studied. In this study, we use quantitative genetic and quantitative trait loci (QTL) analysis to investigate the genetic control of foliar terpenes in an ecologically and commercially important eucalypt species, Eucalyptus globulus. We show a moderate to high within-family broad-sense heritability and significant genetic basis to the variation in 14 of the 16 terpenes assayed. This is the first report of QTL for terpenes in this species. Eleven QTL influenced the terpenes overall. One QTL on linkage group 6 affected six of the seven different sesquiterpenes assayed (plus one monoterpene), which, in combination with highly significant correlations between these compounds, argues that their variation is influenced by a QTL with pleiotropic effect early in the biosynthetic pathway. We examine the homology of these QTL to those found in a closely related eucalypt, Eucalyptus nitens, and provide evidence that both common and unique QTL influence terpene levels.     

Neuroprotective Effects of Withania somnifera on 4-Hydroxynonenal Induced Cell Death in Human Neuroblastoma SH-SY5Y Cells Through ROS Inhibition and Apoptotic Mitochondrial Pathway

Neurochemical Research - The antioxidant, anti-inflammatory, and anticancer activities of Withania somnifera (WS) are known for a long time. This study was aimed to examine whether WS also...