Publications by authors named "Masami Harada"

An identification method for testing contamination in products was assessed using various vegetables and fruits (70 types in total). DNA was extracted from plant fragments which are 1 to several millimeters long and the plastid rpl16-rpl14 linker sequence (approximately 550 base pairs) was amplified by PCR. The DNA nucleotide sequence was determined, and homology and SNP (single nucleotide polymorphism) analyses were carried out.

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Polymorphism in the mitochondrial gene ND5 enables the determination of the order, a taxonomic rank, of many insects from the 5 major insect orders-Diptera, Hymenoptera, Hemiptera, Coleoptera, and Lepidoptera. DNA nucleotide sequences of multiple species were determined and more than 19 nucleotides characteristic of each order were identified; this makes it possible to discriminate insects at the order level more precisely and easily than when using conventional techniques.

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We recently reported polymorphism in the mitochondrial genes of Tribolium castaneum, a stored grain pest. Here, we show that T. castaneum samples from the main island of Japan can be easily differentiated from samples from other areas by using real-time PCR with minor groove binding (MGB) TaqMan probes containing a single nucleotide polymorphism (SNP) to amplify a 179-bp fragment.

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Tribolium castaneum, a pest of stored grain, has a uniform morphology, preventing the visual identification of strains from different areas. Polymorphisms in the nucleotide sequences of the mitochondrial genes of this species were examined, and combined into seven haplotypes among the test insect specimens originating from Japan, Thailand, and Canada. These results suggested the potential for geographical differentiation.

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Three unknown colors (A1, A2 and A3) in Food red No. 102 (R102) were identified by LC-MS and NMR analysis. Red dye A1 was azo rubine (AZO), which is not designated as a coloring agent in Japan.

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Antioxidative effects of sesamin (a mixture of sesamin and episesamin) were evaluated in the liver, kidney and inferior vena cava of living rats using a radiofrequency ESR method. TEMPOL, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl, was used as an in vivo redox probe, the half-life of which is believed to be correlated with the antioxidant status. The oral administration of sesamin (250 mg/kg rat weight) 3 h before ESR measurements shortened the half-life of TEMPOL in the liver by 10 - 15% as compared with the controls, but did not affect the other organs.

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Sesamin, a major lignan in sesame oil, is known to have many biological activities, especially protective effects against oxidative damage in the liver. As sesamin itself has no antioxidative properties in vitro, to elucidate the mechanism of its antioxidative effects, the reaction products of sesamin in rat liver homogenate were analyzed. The methylenedioxyphenyl moiety in the structure of sesamin was shown to be changed into a dihydrophenyl (catechol) moiety.

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We have shown that drinking red wine reduces oxidation of LDL. This reduction in oxidation has been attributed to the polyphenolic compounds in red wine, but the mechanisms of absorption and metabolism of these compounds has been unclear. We therefore investigated the absorption and metabolism of polyphenols using rats to identify their active forms in biological fluids.

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