A particulate insoluble fraction from Candida albicans NIH B-792 (serotype B) strain cells was obtained as the residue after extracting a 105000Xg pellet of cell homogenate with 1% Triton X-100.Incubation of this fraction with a mannopentaose, Manal-3Manal-t2Manal-+Manal+2Man, in the presence of GDP-mannose and MnZ+ at pH 6.0 gave a branched mannohexaose, Manal+3Manal-2Manal-t2Manal-+2Man, f6 Manal the structure of which was identified by means of sequential NMR assignment, However, the enzyme fraction obtained from Candida parapsilosis gave Mana1+2Manal-3Manal+2Manal-2Manal-2-Man under the same conditions. These results demonstrate the finding that the structural difference in the mannans of these two species is due to the presence of a-1,6-linked branching mannose units in the C. albicans mannan [Shibata, N., Ikuta, K., Imai, T., Satoh, Y., Satoh, R., Suzuki, A,, Kojima, C., Kobayashi, H., Hisamichi, K. & Suzuki, S. (1995) J. Biol. Chem. 270, 1113-11221. The substrate-specificity study of the enzyme indicated that the structural requirement of the a-l,6-mannosyltransferase is Manal-3-Manal-. The a-l,6-mannosyltransferase also transferred the a-l,6-linked branching mannose unit to the mannan of Saccharomyces cerevisiue. The transformation of the mannan was detected by the appearance of antigenic factor 4 using an enzyme-linked immunosorbent assay and two-dimensional homonuclear Hartmann-Hahn spectroscopy.Keywords: Candida ulbicans; mannosyltransferase ; mannan ; NMR; biosynthesis.The pathogenic yeast Candidu species is the leading cause of disseminated fungal infection in the immunocompromised host, the diabetic, the neonate, and the post-operative patient. An outburst of severe infections caused by Candida species, especially in patients with impaired immune defense systems, led us to investigate these microorganisms in detail including the study of their cell wall components. Candida albicans is the most virulent strain and has been divided into two serotypes, A and B, based on the antigenicity of the cells [I]. Tsuchiya et al.[2] determined the antigenic patterns of medically important yeasts by cross-adsorption experiments and proposed antigenic formulas for their serologic classification. Namely, C. albicans serotype A has antigenic factors 1, 4, 5 , and 6, while serotype B shows antigenic factors 1, 4, 5, and 13b. In a previous study [3], we detected and characterized the /I-1 ,Zmannosyltransferase I1 which participates in the biosynthesis of the serotype A specific epitope [4, 51, factor 6 [6]. This enzyme transfers a mannose unit from GDP-mannose to Manpl-2Manal-2 Manal-+2Manal-+2Man and synthesizes Manpl-+2Man~I--2Manal-+2Manal+2Manal+2Man. found the presence of a-1,6-branched mannohexaose and mannoheptaose side chains,

In order to clarify the distribution of antigenic oligomannosyl side chains in the cell wall mannans of the pathogenic yeast Candida tropicalis, the chemical structure of mannans isolated from four C. tropicalis strains was investigated using nuclear magnetic resonance, two-dimensional homonuclear Hartmann-Hahn (2D-HOHAHA) spectroscopy. Two-dimensional maps of the 2D-HOHAHA clearly showed the distribution of oligomannosyl side chains in the mannans. The linear side chain Manalpha1-3Manalpha1-(2Manalpha1-)(n)2Man [n> or =2] is present in the mannans from C. tropicalis IFO 0589 and IFO 1400, but not in the mannans from IFO 0199 and IFO 1647. The mannan of IFO 0589 is the only mannan with the branched side chains, Manalpha1-3[Manalpha1-6]Manalpha1-(2Manalpha1-)(n)2Man and Manalpha1-2Manalpha1-3[Manalpha1-6]Manalpha1-(2Manalpha1-)(n)2Man [n> or =2]. However, this mannan lacked the phosphate group and the beta-1,2-linked oligomannosyl side chain which are features of this group. The mannans of the C. tropicalis strains IFO 0589 and IFO 1400 possessed the side chains containing an alpha-1,3-linked mannose residue previously observed in Candida albicans.

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We investigated the antigenic determinants of factorsadherence of Candida cells to mammalian tissues during the 8, 9, and 34 of the genus Candida among pathogenic yeasts by initial step of infection [11]. Therefore, the cell wall compoenzyme-linked immunosorbent assay (ELISA) using mannans of nents containing mannose residues in the o~ configuration

The present study demonstrates the ability of magnetic markers for measuring biological targets without BF separation. This detection system has great potential for use as the next generation's analytical system.