Cells of Candida albicans, a pathogenic yeast, have been show11 to contain, in addition to chitin, a glucan ([ff]~ -30") and a mannan ( [ a ]~ +78") i n the approximate ratio of 1.00:0.84. The two polysaccharides were easily distinguishable by 1110ving boundary electrophoresis in borate butler and were separated froin each other by fractionation of their copper complexes. i\/Iethylation and hydrolysis of the glucan yielded the following 0-methyl ethers of D-glucose: 3,3,4,6-tetra-0-methyl ('7 moles); 2,3,4-tri-0-nlethyl (13 moles); 2,4,8-tri-0-methyl (trace); 2,4-di-0-methyl (8 ~noles); and 2-0-methyl (1 mole). It was concluded that the glucan was a highly branched polysaccharide containing 0 1 + 8 and 0 1 + 3 linked residues. Periodate oxidation of the glucan supported this conclusion.Methylation and hydrolysis of the mannan yielded the following 0-methyl ethers of D-mannose: 2,3,4,8-tetra-0-methyl (1.65 moles); 3,4,6-tri-0-methyl (1.00 mole); 2,3,6-tri-0-methyl (0.18 mole); 3,4-di-0-methyl (1.90 moles). The mannan was therefore a highly branched polysaccharide with short chains of a 1 + 2 linked mannose residues joined together by a 1 + 8 linkages. Results of periodate oxidation agreed with this structure.The diaerences between these two polysaccharides and g l~~c a n s and mannans found in other yeasts are discussed.Structural investigations of polysaccharide components of yeasts have been limited, with only one exception, to those in bakers' yeast (Saccharo?lzyces cerevisiae) and there are a number of reports dealing with the glucan (1-4) and mannan (5-7) that occur in this species. The only report dealing with structures of polysaccharides from other yeast species appears to be that by Gorin and Perlin ( 8 ) which described a mannan produced by S n c c h a r o m y c e s r o u x i i . There have been other publications on the composition of cell \valls of jqeasts (9-18) and some of these (13-18) have dealt with species other than S a c c h n r o m y c e s cerevisiae. However, these papers were concerned pri~iiarily with examination of fractions of yeast cell walls by X-ray diffraction, electrophoresis, and chromatography of hydrolyzates; structures of pol>-saccharides were not investigated and co~lstituent sugars were identified only by paper chromatography. The identification of D-al-abinose as a constituent of polysaccharides found in N o c a r d i a a s t e r o i d e s ( 1 0 ) and I l f y c o b a c t e r i u m t~l b e r c z~l o s i s(20) has shown that sugars can occur in unusual configurations in microorganisms. For this reason the distinction of enantionlorphic forms of naturally occurring sugars is of considerable significance and such distinction cannot be made by paper chromatography. I t was therefore of interest to examine the polysaccharides of another species of yeast, C. albica?zs, to see if they differed in structure or constitue~lt sugars fro111 the polrsaccharides of bakers' yeast. In addition to this a report that the polysaccharides of C. n l b i c a n s , a pathogenic yeast, are ...

The fast-death factor in Microcystis aeruginosa NRC-1 is an acidic, probably cyclic peptide containing the following amino acids in the molar ratios indicated: L-aspartic (1); L-glutamic (2); D-serine (1); L-valine (1); L-ornithine (1); L-alanine (2); L-leucine (2). It is possible, although not likely, that one of the residues of glutamic, alanine, or leucine also is in the D-configuration. The toxin, in the form of its sodium salt, was extracted from lyophilized algal cells by water, separated from pigments by extraction into n-butanol, and freed from high-molecular-weight impurities by dialysis. No separation of a single toxic compound could be obtained by countercurrent distribution, chromatography, or electrophoresis in carbonate, acetate, or phosphate buffers. Electrophoresis of the crude toxin on cellulose in 0.1 M borate yielded five peptides one of which was toxic and accounted for 100% of the toxicity present in the crude preparation. The intraperitoneal LD50 of the pure toxin for mice was 0.466 ± 0.013 mg/kg body weight.

Mannans have been isolated from cells of the following Candida species: C. albicans (serotype A), C. albicans (serotype B), C. parapsilosis, C. stellatoidea, and C. tropicalis. Methylation and hydrolysis of each mannan yielded the following methyl ethers of d-mannose (with only small variations in the relative amounts): 2,3,4,6-tetra-O-methyl-d-mannose, 3,4,6-tri-O-methyl-d-mannose (major), 2,3,4-tri-O-methyl-d-mannose (minor), 2,4,6-tri-O-methyl-d-mannose (minor), 3,4-di-O-methyl-d-mannose, and 3,5-di-O-methyl-d-mannose. The mannans therefore contained a predominance of 1 → 2 linkages in the linear portions, with smaller amounts of 1 → 6 and 1 → 3 linkages. Branching occurred through C-2 and C-6 of d-mannopyranose and d-mannofuranose units, and branches were terminated by d-mannopyranose units. The specific rotations of the mannans indicated that most of the glycosidic linkages were in the α configuration. The structural studies support the observation that the mannans are very similar serologically and show cross-reactivity in antisera to any of the parent organisms.

In studies of the structure and development of primary walls of plant cells, little detailed attention has been given to the non-cellulosic components of the wall. Indeed, as Bonner (6, p. drous calcium chloride for at least 18 hours. Hydrolyses were carried out by heating samples of 10 to 20 mg of the various fractions with 1 ml N hydrochloric acid in a sealed tube at 1000 C for 8 hours. Chromatograms were run by the descending method (17) using one of the following solvent systems: (A) pyridine ethyl acetate : water-i : 2 : 2 (11); (B) ethyl acetate acetic acid: water-3 1: 3 (11); (C) n-butanol : pyridine: water-6 4: 3 (10). Sugars were detected on the chromatograms by the p-anisidine hydrochloride spray reagent (10) and were chromatographically identified by running samples of known sugars on the same paper sheet. At least two solvent systems were used to establish this identification. Nitrogen was determined on 15 to 25 mg samples by the micro-Kjeldahl method and protein was taken as 6 times the micro-Kjeldahl value.The supernatant and washings from the ground coleoptiles were dialyzed in Visking cellophane tubing against fresh distilled water for three 24-hour periods. A precipitate which formed inside the dialysis tube was centrifuged, washed once with water and dried to give Fraction 1 (0.5323 g; N, 9.85 % = 59 % protein). After hydrolysis, chromatography (solvents A and C) revealed the presence of arabinose, xylose, glucose and galactose in the approximate ratios shown in table I.The supernatant liquor from Fraction 1 was concentrated to 1/20 its volume and ethanol was added until precipitation was complete. The precipitate was centrifuged and dried to give Fraction 2 (0.3166 g; N, 5.26 % = 32 % protein). Hydrolysis and chromatography (solvents A and C) showed the presence of arabinose, xylose, glucose and galactose (table I).The ethanolic mother liquors from Fraction 2 were evaporated to dryness and the residue was redissolved in ethanol. Addition of ether caused precipitation of Fraction 3 which was washed once with ether and dried (0.2360 g; N, 3.6 % = 22 % protein). Arabinose, xylose and glucose were detected chromatographically (solvents A and C) after hydrolysis. Evaporation of the supernatant liquor from Fraction 3 left no residue indicating that Fractions 1, 2 and 3 together represented all of the non-dialyzable material washed from the coleoptiles by water.The washed sediment from the original ground coleoptiles was dried in air, ground through a Wiley mill (20-mesh screen), and dried to constant weight at a pressure of 0.03 mm Hg over phosphorus pentoxide. For convenience, this dried product (Fraction 4; 4.8286 g after removal of 0.0255 g for N determination; N, 1.58 % = 9.5 % protein) was regarded as the total primary cell wall material to which Fractions 5 to 9 are referred in terms of percent by dry weight (see discussion and table I).Fraction 4 was extracted in a Soxhlet apparatus 283 www.plantphysiol.org on May 10, 2018 -Published by Downloaded from

A B S T R A C T Gas-liquid partition chromatography has been used to separate all of the possible tetraand tri-0-methyl ethers of methyl a-and 0-D-glucopyranoside. Anomeric methyl glycosides of each isomer were well separated except those of 3,4,6-tri-0-methyl-D-glucose. T h e six di-0-methyl-D-glucopyranoses were partially resolved as their methyl glycosides. T h e four possible m o n o -0 -m e t h y~-~-g~~~c o p y r a n o s e s were completely resolved after conversion to the corresponding r n o n o -0 -n~e t h y l -p e n t a -0 -a c e t y~-~-~c i t o~s , a series of compounds which, except for the 6-0-methyl ison~er, have not been reported previously. Quantitative estimations of mixtures containing varying amounts of methyl-2,3,4-tri-O-n1ethyI-P-~-xylopyranoside and n~ethyl-2,3,4,6-tetra-O-methyl-a-~-g1~1copranosie showed that molar ratios of components in a nlixture could be determined with a mean deviation of f 0.5 in 100.