The distribution of membrane-bound monoamine oxidase in 30 strains of various bacteria was studied. Monoamine oxidase was determined by using an ammonia-selective electrode; analyses were sensitive and easy to perform. The enzyme was found in some strains of the family Enterobacteriaceae, such as Klebsiella, Enterobacter, Escherichia, Salmonella, Serratia, and Proteus. Among strains of other families of bacteria tested, only Pseudomonas aeruginosa IFO 3901, Micrococcus luteus IFO 12708, and Brevibacterium ammoniagenes IAM 1641 had monoamine oxidase activity. In all of these bacteria except B. ammoniagenes, monoamine oxidase was induced by tyramine and was highly specific for tyramine, octopamine, dopamine, and norepinephrine. The enzyme in two strains oxidized histamine or benzylamine. Correlations between the distributions of membrane-bound monoamine oxidase and arylsulfatase synthesized in the presence of tyramine were discussed.
We investigated the effects of lauroylcarnitine and palmitoylcarnitine on major tight junction proteins such as claudins in Caco-2 cell monolayers and also examined the involvement of cholesterol in the effects induced by both acylcarnitines on these proteins. We investigated the effects of lauroylcarnitine and palmitoylcarnitine on the barrier function of tight junctions by measuring transepithelial electrical resistance (TEER) and fluorescein isothiocyanate dextran 40,000 (FD-40) flux. A decrease in the TEER value and an increase in FD-40 flux were observed after incubating Caco-2 cell monolayers with lauroylcarnitine and palmitoylcarnitine for 1 h, suggesting the loss of the barrier function of tight junctions. In addition, lauroylcarnitine and palmitoylcarnitine decreased the protein levels of claudin 1, 4, and 5 but not those of claudin 2, 3, 6, or 7. In addition, palmitoylcarnitine and methyl-β-cyclodextrin increased cholesterol release from the plasma membrane. It is suggested that the effects of palmitoylcarnitine and methyl-β-cyclodextrin on claudin 4 and 5 may be associated with cholesterol leakage from the plasma membrane into the apical side. These results indicate that the protein levels of claudin 4 and 5 are decreased by treatment with palmitoylcarnitine and lauroylcarnitine, and that this change is involved in the absorption-enhancing mechanism.
This study examined the effects of the absorption enhancers, acylcarnitines, on efflux transporting systems, including P-glycoprotein (P-gp) and other efflux transporters, and elucidated the importance of acyl chain length and the concentration of acylcarnitine on the activity of efflux transport. The effects of two acyl (lauroyl and palmitoyl) carnitines on the influx and efflux of lucifer yellow and fluorescein isothiocyanate dextran 4,000, which have characteristic vectorial transport, were examined in Caco-2 cell monolayers. Lauroylcarnitine and palmitoylcarnitine increased influx and decreased efflux of these substrates, in a manner dependent on their concentration and acyl chain lengths by increasing influx and inhibiting efflux of the substrates. The results indicated that both the acyl moiety and long acyl chains play important roles in the modification of influx and efflux transport. Because no marked changes in the levels of P-gp protein or the leakage of LDH were observed at 1 h after the application of acylcarnitines, it was concluded that these acylcarnitines had an effect on modulation of the function of P-gp or other efflux transporters without cytotoxicity.
Metal air battery attracts attention as an automobile battery, because of its high energy density. In order to reuse the battery, it is necessary to undertake reduction of metal oxide which is generated at the cathode without large environment load. We conducted the reduction of ZnO powder by radio-frequency dielectric heating. The ZnO powder and a reducing agent of organic liquid is put into a reaction vessel, and the tip of the electrode inserted from the top of the vessel is in contact with the surface of the powder. By measuring the spectrum of the blackbody radiation, the temperature was found to be approximately 2000 K. The reduction amount of ZnO increased remarkably when 0.7 to 1.4 mL of methanol was added as a reduction agent to 2.0 g ZnO powder, with a maximum of 27.6 mg at 1.1 mL reached. The reduction amount was smaller when ethanol, acetone, furfural, cyclohexane or dodecane were added as a reduction agent. The maximum energy efficiency is 3.3% without taking the reaction energy of the reduction agent into consideration, whereas it becomes 1.0% when taking it into consideration.
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