14 research outputs found
Chronological and isotope geological study of Cretaceous granitic rocks, upper reach of the Nakagawa river, Fukuoka Prefecture
Early Jurassic granitoids from deep drill holes in the East China Sea Basin: implications for the initiation of Palaeo-Pacific tectono-magmatic cycle
Birefringence and composition of grandite garnet from the Shinyama ore deposit of the Kamaishi mine, Iwate Prefecture, Japan.
Occurrence of glucosylsucrose [α-D-glucopyranosyl- (1→2)-α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside] and glucosylated homologues in cyanobacteria: Structural properties, cellular contents and possible function as thermoprotectants
Little is known about the structure and function of oligosaccharides in cyanobacteria. In this study, a new class of saccharides from Nostoc was identified by MS and NMR techniques, consisting of α-d-glucopyranosyl-(1→2)-[α-d-glucopyranosyl-(1→2)]n-β-d-fructofuranosides ranging from the trisaccharide (n = 1) to decasaccharide (n = 8). In Nostoc ellipsosporum the cell content of saccharides increased 10–20-fold after heat stress (1 day, 40 °C) or during prolonged cultivation. Under these conditions the abundance of homologues of higher molecular mass (> pentasaccharide) increased and finally exceeded that of homologues of lower molecular mass including sucrose. Total intracellular content of the saccharides after heat stress was 5–10 mg·(g dry weight)-1 corresponding to intracellular concentrations of 0.25–0.5% (w/v). A possible role of the oligosaccharides identified is in the protection of enzymes against heat inactivation. Whereas amylase from Nostoc was only weakly protected by the decasaccharide, α-amylase from porcine pancreas was more efficiently stabilized by the octasaccharide and decasaccharide. Evidence is presented for the widespread occurrence of the newly identified saccharides in cyanobacteria. The results are discussed including previous reports on cyanobacterial oligosaccharides and with respect to possible functions of these compounds in the living cell