Metabolism of L-cysteine in rats fed low and high protein diets.

L-Cysteine (5.0 mmol per kg of body weight) was intraperitoneally injected into rats fed a 25% casein or 5% casein diet. Concentrations of acidic and neutral amino acids in various tissues were determined 2 h later. In the rats fed the 25% casein diet there was a tendency for tissue amino acid and glutathione levels to be slightly lower than controls. In the 5% casein diet group, however, concentrations of tissue amino acids and glutathione generally increased after L-cysteine administration. S-(2-Hydroxy-2-carboxyethylthio)cysteine (HCETC,3-mercaptolactate-cysteine disulfide), though in trace amounts, was detected in kidney and blood plasma in the 5% casein diet group. Increases in cysteine-glutathione disulfide in liver, kidney and erythrocytes in the 5% casein diet group were considerable. These results indicate that L-cysteine was rapidly metabolized in the 25% casein diet group through the oxidative pathway, while in the 5% casein diet group, in which liver cysteine dioxygenase activity is supposed to be quite low, the oxidative metabolism of L-cysteine decreased and part of the L-cysteine was metabolized through the transaminative pathway. Administration of 15.0 mmol L-cysteine per kg of body weight to rats fed the 25% casein diet resulted in an increase in cysteine-glutathione disulfide in liver, kidney and erythrocytes, and the appearance of HCETC in blood plasma.(ABSTRACT TRUNCATED AT 250 WORDS)</p

Menadione 処理した Candida albicans ROS 生産機構の解析

Menadione shows anti Condida activity by promoting ROS production. However, the ROS production mechanism has not been clarifield. Thus, in this study, we studied thr relation between anti Candida activity of menadione and ROS production. Menadione inhibited the growth of C. albicans BWP17 strain, the growth of C. albicans JM02 strain was not inhibited. ROS production in C. albicans BWP17 strain was enhanced by addition of menadione. The ROS production in C. albicans JM02 strain was also enhanced by menadione, however, the amount of ROS was lower than that in menadione untreated C. albicans BWP17 strain. NDH51 is 51-kDa subunit of NADH dehydrogenase complex I, and C. albicans JM02 strain is deficient in NDH51 strain. Rotenone, an NADH dehydrogenase complex I inhibitor, decreased the menadione sensitivity of the C. albicans BWP17 strain, indicating that NDH51 related to the menadione sensitivity of C. albicans. The expression of NDH51 mRNA was increased by menadione in C. albicans BWP17 strain. These results indicated that menadion inhibited the growthe of C. albicans by stimulating the ROS production system though activation of NDH51 in C. albicans

N-アセチルノイラミン酸によるCandida albicans形態変化の制御について

Candida albicans is a dimorphic fungus and generally grows in hyphal form in RPMI1640 medium. However, addition of N-acetylneuraminic acid inhibited the hyphal growth. The expression of CGR1 mRNA in C. albicans was inhibited by addition of N-acetylneuraminic acid. Diltiazem, a calcium channel blocker, inhibited the yeast to hyphal transformation in C. albicans as well as addition of N-acetylneuraminic acid. These results indicated that inhibition of hyphal growth of C. albicans by N-acetylneuraminic acid was mediated by interruption of CGR1 mRNA expression

菌密度変化に伴うCandida albicansの増殖時形態変化メカニズムの解析

Candida albicans generally grows in hyphal form in RPMI-1640 medium. However, transformation of hyphal form to yeast form is observed by increasing of the cell density in RPMI-1640 medium. Intracellular Ca^ was increased in yeast growth condition (high cell density condition) compared with that of hyphal growth condition. The expression of CGR1 mRNA was inhibited in the yeast growth condition. These results indicated that the transformation of C. albicans was mediated by Ca^-dependent stimulation system, and the system was regulated by CGR1 expression

pH変化によるCandida albicans形態変化シグナルの解析

Candida albicans generally grows in hyphal form in RPMI-1640 medium. However, transformation of hyphal form to yeast form is inhibited by declining pH in RPMI-1640 medium and low pH enhance the yeast like forming. The expressions of RAS1, EFG1, ALS1 and CYR1 mRNA in low pH conditions are significantly decreased compared with that of neutral pH conditions. These results suggested that the transformation of C. albicans may be regulated by pH-dependent stimulation system, and the system was regulated by RAS1 expression