Helio Kiyoshi Takahashi

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Significant differences exist between mammals and fungi with respect to glycosphingolipid (GSL) structure and biosynthesis. Thus, these compounds, as well as the cellular machinery regulating their expression, have considerable potential as targets for the diagnosis and treatment of fungal diseases. In this study, the major neutral GSL components extracted(More)
Two major acidic glycolipid components (Pb-1 and Pb-2) have been extracted from the mycopathogen Paracoccidioides brasiliensis, a thermally dimorphic fungus endemic to rural areas of South and Central America. Sera of all patients exhibiting paracoccidioidomycosis were found to be reactive with Pb-1, but not with Pb-2; no reactivity was observed with sera(More)
Mucin glycoproteins are major secretory products of the colon and contain O-linked oligosaccharides synthesized on a polypeptide backbone. The initial step in the synthesis of O-linked oligosaccharides is the addition of N-acetylgalactosamine to serine or threonine residues forming the Tn antigen. This substance can then receive additional carbohydrate(More)
Paradoxical growth (PG) has been described for echinocandins and is characterized by cell growth at drug concentrations above the MIC. In this study, two isolates each of Candida albicans, C. tropicalis, C. orthopsilosis, and C. parapsilosis, all of which displaying PG in response to caspofungin, were subjected to MIC, minimal fungicidal concentration(More)
Fungal cerebrosides (monohexosylceramides, or CMHs) exhibit a number of ceramide structural modifications not found in mammalian glycosphingolipids, which present additional challenges for their complete characterization. The use of Li+ cationization, in conjunction with electrospray ionization mass spectrometry and low energy collision-induced dissociation(More)
Major neutral glycosphingolipid components were extracted from Sporothrix schenckii, a dimorphic fungus exhibiting a hyphal saprophytic phase and a yeast parasitic phase responsible for chronic mycotic infections in mammalian hosts. These components, one from the mycelial form and two from the yeast form, were purified and their structures were elucidated(More)
In most ascidian species the oocytes are surrounded by two types of accessory cells called follicle cells and test cells. Test cells are located on the periphery of oocytes and remain in the perivitelline space during egg development until hatching. Heparin and histamine were previously described in the test cells of the ascidian Styela plicata. In the(More)
In the present study, we describe the isolation of glycolipids from yeast and mycelium forms of Paracoccidioides brasiliensis. Both forms contains glucosylceramide as the only neutral glycosphingolipid and two acidic glycolipids termed band 1 and band 2. Band 1 was found to be reactive with 100% of sera of patients with paracoccidioidomycosis tested.(More)
A mouse monoclonal antibody, MEST-1, was produced against Band 1 glycolipid antigen of Paracoccidioides brasiliensis. The glycan structure of Band 1 antigen was recently elucidated and the monosaccharides sequence was defined as: Galf beta 1-->6(Manp alpha 1-->3)Manp beta 1-->2Ins. The reactivity of MEST-1 MAb was determined by solid-phase radioimmunoassay(More)
Cerebroside (monohexosylceramide) components were identified in neutral lipids extracted from both the yeast and mycelial forms of the thermally dimorphic mycopathogen Histoplasma capsulatum. The components were purified from both forms and their structures elucidated by 1- and 2-dimensional nuclear magnetic resonance (NMR) spectroscopy, electrospray(More)