Effects of yokukansan, a traditional Japanese medicine, on proliferation and differentiation of oligodendrocytes were examined using purified mouse cortical oligodendrocyte precursor cells (OPCs). OPCs were cultured f...Effects of yokukansan, a traditional Japanese medicine, on proliferation and differentiation of oligodendrocytes were examined using purified mouse cortical oligodendrocyte precursor cells (OPCs). OPCs were cultured for four days, and proliferation was evaluated by counting A2B5 (a specific antibody to OPC)-reactive cells on the second day of cell culture. Differentiation from OPC to oligodendrocyte was evaluated by counting O4 (a specific antibody to detect differentiated cells in various stages)-reactive cells on the fourth day of culture. The effects of yokukansan (final concentration: 100 or 200 μg/ml) on proliferation and differentiation were examined by adding it to the medium for four days. Yokukansan increased not only the number of A2B5-positive cells on the second day but also the number of O4-positive cells on the fourth day compared to those in the corresponding controls. A WST-8 assay was used to identify active components from seven components of Uncaria Hook (UH), one of the constituent galenicals of yokukansan. Geissoschizine methyl ether (GM: 0.1 - 3.0 μM) was identified by this screening assay and increased the number of A2B5-positive cells on the second day and O4-positive cells on the fourth day as yokukansan did. These results suggest that yokukansan promotes the proliferation and differentiation of oligodendrocytes, and also that GM contained in UH is one of active components responsible for this effect of yokukansan.展开更多
Corrosion of iron-containing metals under sulfate-reducing conditions is an economically important problem.Microbial strains now known as Desulfovibrio vulgaris served as the model microbes in many of the foundational...Corrosion of iron-containing metals under sulfate-reducing conditions is an economically important problem.Microbial strains now known as Desulfovibrio vulgaris served as the model microbes in many of the foundational studies that developed existing models for the corrosion of iron-containing metals under sulfate-reducing conditions.Proposed mechanisms for corrosion by D.vulgaris include:(1)H2 consumption to accelerate the oxidation of Fe0 coupled to the reduction of protons to H2;(2)production of sulfide that combines with ferrous iron to form iron sulfide coatings that promote H2 production;(3)moribund cells release hydrogenases that catalyze Fe0 oxidation with the production of H2;(4)direct electron transfer from Fe0 to cells;and(5)flavins serving as an electron shuttle for electron transfer between Fe0 and cells.The demonstrated possibility of conducting transcriptomic and proteomic analysis of cells growing on metal surfaces suggests that similar studies on D.vulgaris corrosion biofilms can aid in identifying proteins that play an important role in corrosion.Tools for making targeted gene deletions in D.vulgaris are available for functional genetic studies.These approaches,coupled with instrumentation for the detection of low concentrations of H2,and proven techniques for evaluating putative electron shuttle function,are expected to make it possible to determine which of the proposed mechanisms for D.vulgaris corrosion are most important.展开更多
文摘Effects of yokukansan, a traditional Japanese medicine, on proliferation and differentiation of oligodendrocytes were examined using purified mouse cortical oligodendrocyte precursor cells (OPCs). OPCs were cultured for four days, and proliferation was evaluated by counting A2B5 (a specific antibody to OPC)-reactive cells on the second day of cell culture. Differentiation from OPC to oligodendrocyte was evaluated by counting O4 (a specific antibody to detect differentiated cells in various stages)-reactive cells on the fourth day of culture. The effects of yokukansan (final concentration: 100 or 200 μg/ml) on proliferation and differentiation were examined by adding it to the medium for four days. Yokukansan increased not only the number of A2B5-positive cells on the second day but also the number of O4-positive cells on the fourth day compared to those in the corresponding controls. A WST-8 assay was used to identify active components from seven components of Uncaria Hook (UH), one of the constituent galenicals of yokukansan. Geissoschizine methyl ether (GM: 0.1 - 3.0 μM) was identified by this screening assay and increased the number of A2B5-positive cells on the second day and O4-positive cells on the fourth day as yokukansan did. These results suggest that yokukansan promotes the proliferation and differentiation of oligodendrocytes, and also that GM contained in UH is one of active components responsible for this effect of yokukansan.
文摘Corrosion of iron-containing metals under sulfate-reducing conditions is an economically important problem.Microbial strains now known as Desulfovibrio vulgaris served as the model microbes in many of the foundational studies that developed existing models for the corrosion of iron-containing metals under sulfate-reducing conditions.Proposed mechanisms for corrosion by D.vulgaris include:(1)H2 consumption to accelerate the oxidation of Fe0 coupled to the reduction of protons to H2;(2)production of sulfide that combines with ferrous iron to form iron sulfide coatings that promote H2 production;(3)moribund cells release hydrogenases that catalyze Fe0 oxidation with the production of H2;(4)direct electron transfer from Fe0 to cells;and(5)flavins serving as an electron shuttle for electron transfer between Fe0 and cells.The demonstrated possibility of conducting transcriptomic and proteomic analysis of cells growing on metal surfaces suggests that similar studies on D.vulgaris corrosion biofilms can aid in identifying proteins that play an important role in corrosion.Tools for making targeted gene deletions in D.vulgaris are available for functional genetic studies.These approaches,coupled with instrumentation for the detection of low concentrations of H2,and proven techniques for evaluating putative electron shuttle function,are expected to make it possible to determine which of the proposed mechanisms for D.vulgaris corrosion are most important.
