NMR and rheological study of Aloe barbadensis partially acetylated glucomannan

AbstractThe structural and rheological properties of the Aloe extract (AE) and the polysaccharidic fraction (PF) obtained from the leaves pulp of Aloe barbadensis Miller were investigated. Structural analyses carried out by composition, methylation analysis and NMR spectroscopy showed that PF is mainly constituted by a partially acetylated 4-linked β-d-glucomannan. The acetyl groups are located at C-2, C-2 and C-3, C-3 and/or C-6. The acetylation pattern of this type of polysaccharide was for the first time established using bidimensional NMR analyses. AE and PF aqueous solutions at 25°C showed a non-Newtonian behavior (with pseudoplastic characteristics), however PF showed higher apparent viscosity than AE. Dynamic oscillatory analyses showed that both samples, at the same concentration, behaved as a concentrated solution. PF presented higher values of G′ compared with those of AE and this behavior could be consequence of its higher content in partially acetylated glucomannan

Development and Application of a Salmonid EST Database and cDNA Microarray: Data Mining and Interspecific Hybridization Characteristics

We report 80,388 ESTs from 23 Atlantic salmon (Salmo salar) cDNA libraries (61,819 ESTs), 6 rainbow trout (Oncorhynchus mykiss) cDNA libraries (14,544 ESTs), 2 chinook salmon (Oncorhynchus tshawytscha) cDNA libraries (1317 ESTs), 2 sockeye salmon (Oncorhynchus nerka) cDNA libraries (1243 ESTs), and 2 lake whitefish (Coregonus clupeaformis) cDNA libraries (1465 ESTs). The majority of these are 3′ sequences, allowing discrimination between paralogs arising from a recent genome duplication in the salmonid lineage. Sequence assembly reveals 28,710 different S. salar, 8981 O. mykiss, 1085 O. tshawytscha, 520 O. nerka, and 1176 C. clupeaformis putative transcripts. We annotate the submitted portion of our EST database by molecular function. Higher- and lower-molecular-weight fractions of libraries are shown to contain distinct gene sets, and higher rates of gene discovery are associated with higher-molecular weight libraries. Pyloric caecum library group annotations indicate this organ may function in redox control and as a barrier against systemic uptake of xenobiotics. A microarray is described, containing 7356 salmonid elements representing 3557 different cDNAs. Analyses of cross-species hybridizations to this cDNA microarray indicate that this resource may be used for studies involving all salmonids