Cryptococcus, polysaccharide

Nakouzi, A., P. Valadon, J. Nosanchuk, N. Green, and A. CasadevaU, Molecular basis for immunoglobulin M specificity to epitopes in Cryptococcus neoformans polysaccharide that elicit protective and nonprotective antibodies. Infect Immun, 2001. 69(5) 3398-409. 

Goldman DL, Casadevall A, Zuckier LS. Pharmacokinetics and biodistribution of a monoclonal antibody to Cryptococcus neoformans capsular polysaccharide antigen in a rat model of cryptococcal meningitis implications for passive immunotherapy. J Med Vet Mycol 1997 35(4) 271-8. 

Kooiman separated exocellular amylose formed in liquid media at pH < 5 by Cryptococcus albidus and Cryptococcus laurentii var. flavescens NRRL Y-1401 from a polysaccharide containing D-man-nose, D-xylose, and D-glucuronic acid. X-Ray diffraction patterns of the retrograded amyloses were identical with that of tuber starch (B modification). Periodate oxidation, optical rotational measurements, and hypoiodite oxidation data suggested a linear a-D-(l—>4)-linked structure having a chain length of about 44 units for the Cr. albidus amylose. Cryptococcus neoformans produces a crystalline amylose that was isolated by the method of Schoch. It has an iodine value and alpha- and hefa-amylase hydrolysis characteristics similar to those of corn amylose. 

The capsular polysaccharide of the pathogenic yeast Cryptococcus neoformans (Torula histolytica) is serologically active, and there is evidence that it is responsible for the antigenic reaction in man. The capsule is generally quite thick, and can be larger in diameter than the cell body. Three polysaccharide types, namely. A, B, and C, have been differentiated on the basis of precipitin, agglutination, and quellung reactions. ... 

Cryptococcus (19) none varied, but all use mi/o-inositol spherical, oval, or elongate budding-cells, usually with a polysaccharide capsule not filamentous 24,43... 

Banters et al. (2003) demonstrated Cryptococcus neoformans in cerebrospinal fluid (CSF) and serum. Their 30-min procedure was based on the non-specific labelling with ChemChrome V3 in combination with a second analysis using immunofluorescence. To that end, cells were labelled with a specific primary antibody against a capsular polysaccharide and a secondary antibody conjugated with FITC. 

Only the specific polysaccharide of Cryptococcus neoformans Type A, which, like that of Types B and C, contains mainly mannose and xylose, with smaller proportions of D-galactose and D-glucuronic acid residues, - cross-reacted in anti-Pn Fractionation of the Type A polysac-... 

Many other fungal mannans are heteropolymers based on an a-mannan chain [84, 55]. a-L-Rhamno-a-mannans with L-Rha al—>3, L-Rha al-2-L-Rha al—>3 and L-Rhal-4GlcAp 1 -2-L-Rhaa 1 —>3 side chains have been described. a-Gluco-a-mannans with single Glc residues attached to the mannan chain have been isolated from Ceratocystis spp. The capsular polysaccharides of the serotype of an encapsulated pathogenic yeast, Cryptococcus neoformans, have a main chain of a(l-3)... 

A nonfermentative yeast. Cryptococcus laurentii, produces a capsular polysaccharide that contains D-mannose, D-xylose, and D-glucuronic acid residues in the approximate molar ratios of 5 2 1. Structural studies indicate that the polysaccharide has a backbone of D-mannose residues, with D-xylose and D-glucuronic acid residues as end groups. A particulate fraction from this organism was shown to catalyze the transfer of the D-xylosyl group from its UDP derivative to acceptor polysaccharides. The transferase can be solubilized with digitonin. Partially de-D-xylosylated capsular polysaccharide from the parent strain is most active as the acceptor, and similarly treated polysaccharides from related species are active to a lesser degree. Neither untreated capsular polysaccharides from these strains nor S. cerevisiae mannan showed any activity as an acceptor. 

Tremella/Cryptococcus. The first definitive compositional and structural studies (, ) on a member of this family of polysaccharides were done on the heteropolysaccharide produced by C. laurentii var. flavescens NRRL Y-1401. Because haploid, yeastlike species of the basidiomycetous genus Tremella formed glucu-ronoxylomannans (GXM) similar to those from species of Crypto-coccus, a taxonomic relationship was suggested between the genera "(576)7 Basidiomycetous perfect states were subsequently discovered for C. laurentii (7 ) and C. neoformans ( ). 

Table I further illustrates that the exocellular acidic polysaccharides from Tremella are generally more highly xylo-sylated than those from Cryptococcus and display more negative optical rotations ( 5). Positive increases in specific rotations of partially dexylosylated T. mesenterica GXM (, ) suggest that D-xylosyl residues occur as 3-linked outer chains.

The highly branched capsular polysaccharide from Cryptococcus neoformans serotype c consists of a backbone of (1 3 )-Q -D-mannopyranosyl residues with single chain non-reducing (1 -> 2)- and (1 4)-/3-D-xylopyranosyl- and (1 2)-/3-... 

Goldman D, Song X, Kitai R, Casadevall A, Zhao ML, Lee SC. Cryptococcus neoformans induces macrophage inflammatory protein 1 alpha (MIP-1 alpha) and MIP-lbeta in human microglia role of speciflc antibody and soluble capsular polysaccharide. Infect Immun 2001 69 1808-1815. 

Shoham S, Huang C, Chen JM et al. Toll-like receptor 4 mediates intracellular signaling without TNF-a release in response to Cryptococcus neoformans polysaccharide capsule. J Immunol 2001 166 4620-4626. 

Constit. of the side chain of the serological type B capsular polysaccharide in Cryptococcus bacillisporus. 

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