Shiro Sugawara

α-Mannosidases from suspension-cultured sugar beet cells.

Abstract The majority of intracellular α-mannosidase activity from suspension-cultured sugar beet cells was of vacuolar origin. Cell wall bound α-mannosidase was mostly extracted from purified cell wall after successive treatment with deoxycholate, saline and EDTA, commerical cellulase and pectinase. Soluble and cell wall bound α-mannosidase were purified separately to homogeneity. Soluble and cell wall α-mannosidases were nearly similar regarding profiles of activity with changing pH and temperature, K m value for p -nitrophenyl-α- d -mannoside, M r , and sensitivity to various metal ions and EDTA. Soluble α-mannosidase was composed of four different subunits ( M r , 72 000, 62 000, 57 000 and 34 000) and wall bound enzyme, three subunits ( M r , 72 000, 62 000 and 34 000). To compare α-mannosidase from dedifferentiated cells with that from differentiated cells, intracellular enzyme from mature roots was also purified to homogeneity. Both the intracellular α-mannosidase from mature roots and that from cultured cells exhibited similar behaviour during their purification and were nearly similar regarding some properties. The enzyme was composed of two different subunits ( M r , 72 000 and 34 000).

Difference of infectivity between two similar soybean rhizobial strains and immunohistochemical evidence of double infection

Abstract Two strains of soybean rhizobia (Bradyrhizobium japonicum OUG 115 and OUG 117), which were very similar in their microbiological properties but not in their imrnunological response, were tested for nodulation of Glycine max. Strain-specific antisera were obtained by adsorbing the antisera with the cross-reactive cellular antigen. The strains in the nodules formed were identified by cross agglutination and fluorescent immunohistochemical (FIHC) methods using the antibodies labeled with fluorescein isothiocyanate (FITC). Microscopic observation revealed clearly the difference of infectivity between the two strains. About 80 and 7.5% of the nodules tested were found to contain one strain, OUG 117 or OUG 115, respectively, and doubly infected nodules were estimated at 13%, when soybean was inoculated with the same concentration of the two strains.

Biochemical and serological characteristics of two similar soybean rhizobia

Abstract Two slow-growing soybean rhizobial strains (Bradyrhizobium japonicum), OUG 115 and OUG 117, were compared in biochemical and serological experiments. A slight difference was detected in the growth curve in liquid media containing arabinose as a sole carbon substrate, but for the other carbon sources there were no differences between the two strains. Both strains reacted strongly with the corresponding antisera but weakly cross reacted with each other.