yasumasa sugiyama - Academia.edu (original) (raw)

yasumasa sugiyama

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Nahla Ayoub

Umm Al-Qura University, Makkah, Saudi Arabia

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Papers by yasumasa sugiyama

Journal of Bacteriology, Nov 1, 2001

Journal of Natural Products, 2009

Journal of Bacteriology, 2001

The phospholipid composition of Hydrogenobacter thermophilus strain TK-6, an obligately chemolith... more The phospholipid composition of Hydrogenobacter thermophilus strain TK-6, an obligately chemolithoautotrophic, extremely thermophilic hydrogen bacterium, was analyzed. Two of four phospholipids detected from the strain were assumed to be phosphatidylinositol and phosphatidylglycerol. An aminophospholipid named PX, whose content among the phospholipids was 65%, was found to have a novel chemical structure by analysis of the dilyso form with nuclear magnetic resonance and fast atom bombardment-mass spectrometry (FAB-MS) and by analysis of the intact PX with FAB-MS as 1,2-diacyl-3- O -(phospho-2′- O -(1′-amino)-2′,3′,4′,5′-pentanetetrol)-sn-glycerol. Structurally similar phospholipids have been identified in Methanospirillum hungatei , Methanolacinia paynteri , and Methanogenium cariaci , which all belong to the Archaea .

The Journal of Antibiotics, 2010

Bioscience, Biotechnology, and Biochemistry, 2007

Bioscience, Biotechnology, and Biochemistry, 2005

Bioscience, Biotechnology, and Biochemistry, 2004

A simple new assay was designed for lipoxygenase inhibitors. This assay was used to find the nove... more A simple new assay was designed for lipoxygenase inhibitors. This assay was used to find the novel lipoxygenase inhibitor, tetrapetalone A (1). Tetrapetalone A (1), C 26 H 33 NO 7 , was isolated from Streptomyces sp. USF-4727 strain. Its planar structure was determined by spectroscopic evidence and by methylating with diazomethane to show the presence of a novel tetracyclic skeleton and a -D-rhodinosyl moiety. The stereochemistry of 1 was investigated by the coupling constant in the 1 H-NMR spectrum, NOE correlations, modified Mosher's method and derivation. We have reported the structural elucidation of 1 in our previous paper. However, further investigation gave another structure for 1, which is described in this paper. Tetrapetalone A showed similar inhibitory activity against soybean lipoxygenase to the two well-known lipoxygenase inhibitors, kojic acid and NDGA, while methylated tetrapetalone A (2) showed little inhibitory activity, even at a concentration of 1 mM.