The two exocelli~lar polysaccharides of Cnndidn bogorierrsis contain D-mannosc, D-fucose, L-rharnnose, D-plucuronic acid, and D-galactose residues. The main heteropolyn~er ( z 80%) has an a-D-(l+3)-linked lnannan main-chain as shown by s~~ccessivc Smith degradations. Partial hydrolysis of the hcteropoly~liers provided several methylpentose-containing oligosaccharide fragments corresponding to possible sidechain components.Canadian Journal of Chemistry, 46, 3407 (1968) Information on the nature of extracellular and been useful as an aid in classification of t h e parent intracellular polysaccharides of yeasts has often organisms (1)(2)(3)(4)(5)(6)(7)(8). These investigations have now been extended to include other yeasts of the genus 'Issued as NRCC No. 10293. Candida, which are listed in Table I. T h e polyCan. J. Chem. Downloaded from www.nrcresearchpress.com by 54.202.233.140 on 05/11/18For personal use only. (Table I), which were purified and compared by their proton magnetic resonance (p.m.r.) spectra (9). The H-1 portions of the spectra are useful in establishing structural differences and possible similarities between polysaccharides of different species. In contrast, other Candida spp. contain glucans (Candicla javanica CBS 5236 contains glucan only) and complex heteropolymers, and the latter give viscous solutioiis in DzO so that p.m.r. spectra could not be obtained. However, many of the polymers can be distinguished by their sugar composition as shown in Table I. In order to determine whether the main-chain structure of a representative of this heteropolymer group is similar to that of polysaccharides of other yeast genera, some of the structural features of Candidla bogoriensis polysaccharides have now been elucidated. Canclida bogorier~sis forms relatively large quantities of extracellular polysaccharide, which contains the same components, glucuronic acid, fucose, rhamnose, mannose, and galactose, as the aqueous alkali cell extract. The extracellular polysaccharide was isolated in a virtually nitrogen-free state by ethanol precipitation. On ultracentrifugation in 0.1 M aqueous NaC1, a major peak with sozz 60s and a minor peak (<20%) with sozz 9 s were detected. Attempts t o fractionate the components by column chromatography on Biogel A-15m, Sephadex G-200, or by gradient elution on 0-[(2-diethylamino)ethyl]-cellulose in the borate form, were unsuccessful. Treatment of the heteropolymer solutions with cetyltrimethylanimonium bromide or with Fehling's solution gave water-insoluble fractions. Each fraction gave, on hydrolysis, the same sugars as obtained from the original polysaccharmers was only partly successf~ll since fillly methylated material was not obtained. However, paper chromatographic analysis of the fragments formed from partially methylated polysaccharide indicated that fucopyranosyl, rhaninopyranosyl, and galactof~~ranosyl lion-reducing end-units are present. The presence of galactofuranoside residues was also indicated by the release of arabinose on complete hydrolysis of the poly...