Fractional precipitation of d-mannan from bakers' yeast with concanavalin a

Cell wall mannan and cell surface hydrophobicity in Candida albicans serotype A and B strains

Cell surface hydrophobicity contributes to the pathogenesis of the opportunistic fungal pathogen Candida albicans. Previous work demonstrated a correlation between hydrophobicity status and changes in the acid-labile, phosphodiester-linked beta-1,2-oligomannoside components of the N-linked glycans of cell wall mannoprotein. Glycan composition also defines the two major serotypes, A and B, of C. albicans strains. Here, we show that the cell surface hydrophobicity of the two serotypes is qualitatively different, suggesting that the serotypes may differ in how they modulate cell surface hydrophobicity status. The cell wall mannoproteins from hydrophilic and hydrophobic cells of both serotypes were compared to determine whether the glycan differences due to serotype affect the glycan differences due to hydrophobicity status. Composition analysis showed that the protein, hexose, and phosphate contents of the mannoprotein fraction did not differ significantly among the strains tested. Electrophoretic profiles of the acid-labile mannan differed only with hydrophobicity status, not serotype, though some strain-specific differences were observed. Furthermore, a newly available beta-1,2-oligomannoside ladder allowed unambiguous identification of acid-labile mannan components. Finally, to assess whether the acid-stable mannan also affects cell surface hydrophobicity status, this fraction was fragmented into its component branches by acetolysis. The electrophoretic profiles of the acid-stable branches were very similar regardless of hydrophobicity status. However, differences were observed between serotypes. These results support and extend our current model that modification of the acid-labile beta-1,2-oligomannoside chain length but not modification of the acid-stable region is one common mechanism by which switching of cell surface hydrophobicity status of C. albicans strains occurs.

A new mannoheptaose containing alpha and beta-(1-->2) linkages isolated from the mannan of Torulaspora delbrueckii: ELISA inhibition studies

Torulaspora delbrueckii starin IFO 0955 was examined with respect to its structural and serological properties of the cell wall mannan (Td-0955-M). Td-0955-M revealed significant reactivities with sera from a commercially available factor serum kit (Candida Check) in ELISA. Td-0955-M was investigated for its chemical structure by acetolysis under conventional and mild conditions. NMR and GC techniques were used as analytical techniques. The mannooligosaccharide fractions eluted from a Bio-Gel P-2 column were found to consist of Man(alpha1-2)Man, M2, Man(alpha1-2)Man(alpha1-2)Man and Man(beta1-2)Man(alpha1-2)Man, M3, Man(alpha1-2)Man(beta1-2)Man(beta1-2)Man(alpha1-2)Man, M5, and a new mannoheptaose, which possesses the structure, Man(alpha1-2)Man(beta1-2)Man(beta1-2)Man(beta1-2)Man(beta1-2)Man(alpha1-2)Man, M7. The results of the inhibition ELISA showed that the M7 oligosaccharide significantly inhibited the reactivities in the Td-0955-M-factor serum systems.

Production of interleukin-1 activity of Kupffer cells from mice treated with the acidic mannan fraction of baker's yeast

We investigated the production of interleukin-1 (IL-1) activity by Kupffer cells (KC) from mice treated with a neutral mannan fraction (WNM) or an acidic mannan fraction (WAM025) from baker's yeast (Saccharomyces cerevisiae) in vivo and in vitro. The mice administered WAM025 showed an increase in the number of KC and the IL-1 production compared with mice administered WNM. In an in vitro stimulation assay using KC from a normal mouse, it was also found that WAM025 displayed an increase in IL-1 production. Diisopropyl fluorophosphate completely inhibited the production of IL-1 by KC from the mice administered WAM025.

Structure of the D-mannan of Candida stellatoidea IFO 1397 strain. Comparison with that of the phospho-D-mannan of Candida albicans NIH B-792 strain

The structure of the D-mannan of Candida stellatoidea IFO 1397 strain, which has properties identical to those of the phospho-D-mannan of C. albicans serotype B strain, does not contain phosphate groups, and its 1H- and 13C-n.m.r. spectra are quite similar to those of the phospho-D-mannan of C. albicans NIH B-792 strain. However, the 1H-n.m.r. and 1H-13C-correlation n.m.r. spectra of the products obtained by digestion with alpha-D-mannosidase of C. stellatoidea D-mannan considerably differed from those of the corresponding digestion products of the C. albicans phospho-D-mannan. Additionally, the enzyme-linked immunosorbent assay, by means of a monoclonal antibody corresponding to (1----2)-linked beta-D-oligomannosyl residues, of the phospho-D-mannan of the same C. albicans strain indicated that the C. stellatoidea D-mannan does not contain any (1----2)-linked beta-D-oligomannosyl residues. The absence of these residues may be used as one of the criteria of chemotaxonomical identification of C. stellatoidea spp.

Structural analysis of phospho-D-mannan-protein complexes isolated from yeast and mold form cells of Candida albicans NIH A-207 serotype A strain

The immunochemical properties between phospho-D-mannan-protein complexes of yeast (Y) and mycelial (M) forms of Candida albicans NIH A-207 (serotype A) strain were compared. Hydrolysis of the Y-form complex gave a mixture of beta-(1----2)-linked D-mannooligosaccharides consisting mainly of tri- and tetra-ose, whereas the M-form complex gave preponderantly D-mannose. The antiserum against Y-form cells exhibited a lower reactivity with the M-form than with the Y-form complex, whereas the antiserum to M-form cells could not distinguish significantly between both complexes. Moreover, these acid-modified complexes showed lower antibody-precipitating effect than each corresponding intact complex against antisera of Y- and M-form cells. Digestion of the acid-modified Y- and M-form complexes with the Arthrobacter GJM-1 strain alpha-D-mannosidase yielded 35- and 40-% degradation products, respectively. Acetolysis of each modified complex under mild conditions gave the same D-mannohexaose, beta-D-Manp-(1----2)-beta-D-Manp-(1----2)-alpha-D-Manp -(1----2)-alpha-D-Manp- (1----2)-alpha-D-Manp-(1----2)-D-Man. Because the complexes of Y- and M-form cells of C. albicans NIH B-792 (serotype B) strain did not give any hexaose fraction containing beta-(1----2) linkages, the presence of this hexaose can be regarded as one of the dominant characteristics of the serotype-A specificity of C. albicans spp.

Structural study of phosphomannan-protein complex of Citeromyces matritensis containing beta-1,2 linkage. Application of partial acid degradation and acetolysis techniques under mild conditions

The phosphomannan-protein complex of Citeromyces matritensis IFO 0651 strain was investigated for its chemical structure by a sequential degradation procedure, partial acid degradation followed by acetolysis under mild conditions. Upon treatment with 10 mM HCl at 100 degrees C for 1 h, this complex released mannotriose and mannotetraose consisting solely of 1,2-linked beta-D-mannopyranosyl residues, ca. 20% on weight basis of the parent complex. The acid-degraded complex was then subjected to acetolysis using an acetolysis medium of low sulfuric acid concentration, a 100:100:1 (v/v) mixture of acetic anhydride, acetic acid, and sulfuric acid at 40 degrees C for 36 h. A phosphate-containing manno-oligosaccharide fraction eluted in the void-volume region of a Bio-Gel P-2 column was found to consist of Manp beta 1----2Manp beta 1----2Manp alpha 1----2Man to which 1 mol of phosphate group was attached, while a manno-oligosaccharide fraction eluted in the diffusable region was a mixture of Manp beta 1----2Manp beta 1----2Manp beta 1----2Manp alpha 1----2Man, Manp beta 1----2Manp beta 1----2Manp alpha 1----2Man, Manp beta 1----2Manp alpha 1----2Man, Manp alpha 1----2Man, and mannose in the molar ratio of 0.08:0.33:0.19:0.32:1.00. Therefore, the structural analysis of the polysaccharide moiety of a beta-1,2 linkage-containing phosphomannan-protein complex of fungal origin can be achieved by means of a sequential degradation procedure, partial acid degradation followed by acetolysis under mild conditions.

Characterization of phosphomannan-protein complexes isolated from viable cells of yeast and mycelial forms of Candida albicans NIH B-792 strain by the action of Zymolyase-100T

The isolation of phosphomannan-protein complexes from the viable cells of yeast (Y) and mycelial (M) forms of Candida albicans NIH B-792 strain was conducted by treatment with Zymolyase-100T followed by fractional precipitation with cetyltrimethylammonium bromide. The M-form complex was found to contain smaller amount of phosphate (1.3%) than that of the Y-form complex (1.6%). Proton magnetic resonance (PMR) spectra of these complexes indicated that the content of beta-1,2-linked oligomannosyl and nonreducing terminal alpha-1,3-linked mannopyranosyl residues in the M-form complex was lower than that of the Y-form complex. With hot 10 mM HCl, the Y-form complex released a mixture of oligosaccharides ranging from mannose to mannoheptaose, while the M-form complex produced lower oligosaccharides, from mannose to mannotetraose. Upon acetolysis, the acid-modified complex of the M form gave mainly mannotetraose, while that of the Y form produced mainly mannopentaose and mannohexaose in addition to mannotetraose. The average length of branching moieties of the mannan of Y-form cells was therefore longer than that of M-form cells. These results indicate that the Y to M transformation of this C. albicans strain accompanies the suppression of enzyme activity concerning the biosynthesis of mannan such as beta-1,2- and alpha-1,3-mannosyltransferases to synthesize the phosphomannan-protein complex containing mannan moiety with incomplete structure.

Protective effect of acidic mannan fraction of bakers' yeast on experimental candidiasis in mice

An acidic fraction of bakers' yeast mannan, WAM025, showed a significant protective effect against Candida albicans infection in mice, but a neutral fraction of the same bakers' yeast mannan, WNM, did not exhibit this effect. Moreover, pretreatment with WAM025 resulted in a marked reduction of proliferation of C. albicans cells in the organs of the infected mice. We investigated the stimulative effect of these mannan fractions on the function of mouse peritoneal phagocytes, and found that mice administered WAM025 showed a greater increase in the number of peritoneal exudate cells, macrophages and polymorphonuclear leucocytes (PMN), than the mice treated with WNM, especially in the proportion of PMN. Peritoneal phagocytes, PMN and macrophages obtained from WAM025-treated mice showed marked candidacidal activity. Of the phagocytes, PMN were responsible for the larger part of the candidacidal activity. The myeloperoxidase activities of PMN and macrophages in WAM025-treated PEC were greater than in untreated macrophages. The myeloperoxidase activity of WAM025-treated PMN was significantly greater than that of WAM025-treated macrophages. This activity paralleled the active oxygen-releasing activity of the phagocytes. On the other hand, the phagocytic activity of phagocytes from mice administered WNM or WAM025 for C. albicans cells was identical to that of untreated phagocytes. WAM025 seems to cause enhance elimination of the pathogen from mice, by increasing the number and candidacidal activity of phagocytic cells.

Antibiotic tetaine--a selective inhibitor of chitin and mannoprotein biosynthesis in Candida albicans

The antibiotic tetaine inhibits in Candida albicans the biosynthesis of two important cell wall constituents, chitin and mannoprotein. This effect is a consequence of inactivation of the enzyme glucosamine-6-phosphate synthetase. Due to the lack of glucosamine-6-phosphate the effective secretion of mannoprotein enzymes, acid phosphatase and invertase, by Candida albicans spheroplasts is inhibited. In the presence of tetaine, probably a modified mannoprotein, lacking a branched polymannan, is synthesized. The antibiotic action decreases the viability of Candida albicans cells, especially that of mycelial forms of this fungus.

Acetolysis of Pichia pastoris IFO 0948 strain mannan containing alpha-1,2 and beta-1,2 linkages using acetolysis medium of low sulfuric acid concentration

To obtain manno-oligosaccharides containing beta-1,2-linked nonreducing terminal groups from the mannan of Pichia pastoris IFO 0948 strain by acetolysis, an attempt was made to establish the reaction conditions under which cleavage of the alpha-1,6 linkage took place preferentially leaving manno-oligosaccharides composed largely of beta-1,2 linkages. By the action of an ordinary acetolysis medium, a 10/10/1 (v/v) mixture of acetic anhydride, acetic acid, and sulfuric acid at 40 degrees C for 13 h or at 25 degrees C for 120 h, the O-acetyl derivative of this mannan gave mannose, mannobiose, mannotriose, and mannopentaose. However, treatment of the same O-acetyl mannan with a 50/50/1 (v/v) acetolysis medium at 40 degrees C for 15 h gave a mannotetraose in addition to mannose, mannobiose, mannotriose, and mannopentaose. Use of a 100/100/1 (v/v) acetolysis medium at 40 degrees C for 36 h gave a more satisfactory result, a mixture of oligosaccharides, from mannose to mannopentaose, which contained more mannotetraose than mannopentaose. Because both mannotetraose and mannopentaose contained alpha-1,2 and beta-1,2 linkages, it was concluded that an acetolysis medium containing a low concentration of sulfuric acid, up to 0.5% (v/v), facilitates the preferential cleavage of the alpha-1,6 linkage, leaving manno-oligosaccharides containing the beta-1,2 linkage which was found to be labile to the action of the 10/10/1 (v/v) acetolysis medium.

Immunochemical study on the mannans of Candida albicans NIH A-207, NIH B-792, and J-1012 strains prepared by fractional precipitation with cetyltrimethylammonium bromide

The mannans of Candida albicans NIH A-207 (A strain, serotype A), C. albicans NIH B-792 (B strain, serotype B), and C. albicans J-1012 (J strain, serotype C) prepared by fractional precipitation with cetyltrimethylammonium bromide (Cetavlon) were investigated for their immunochemical properties. Upon treatment with 10 mM HCl at 100 degrees C for 60 min, the mannans of A and B strains each released a mixture of manno-oligosaccharides ranging from hexaose to mannose together with (for each one) an acid-modified mannan, while J-strain mannan released lower oligosaccharides, tetraose to mannose. The acid-modified mannan of B strain did not show antibody-precipitating activity against homologous antiserum, whereas acid-modified A- and J-strain mannans retained most of this activity. The acid-released oligosaccharides were assumed to consist of beta-1,2-linked D-mannopyranosyl residues from the results of specific rotation and proton magnetic resonance studies.

Mitogenic effect of the mannans from Saccharomyces cerevisiae on mouse spleen lymphocytes

The DNA synthetic activities of mannans isolated from two Saccharomyces cerevisiae strains were examined in vitro using spleen cells obtained from normal or nude BALB/c strain mice. A highly branched mannan isolated from the S. cerevisiae wild type strain induced a greater increase in mitogenic activity than those displayed by the mannan of the S. cerevisiae X2180-1A-5 mutant strain which possessed fewer branching moieties. Acid-hydrolyzed wild type strain mannan with two-thirds of the molecular weight of the parent intact mannan showed weak mitogenicity. Increases in the DNA synthetic activities of nude and normal spleen cells were almost the same as that of wild type strain mannan, while nylon wool column-passed spleen cells obtained from both normal and nude mice did not show mitogenicity with this mannan. The results indicated that the mitogenic activity was responsible for the highly branched structure of the wild type strain mannan, and that this mannan is a B-cell mitogen.

Growth-inhibitory activity of the D-mannan of Saccharomyces cerevisiae X2180-1A-5 mutant strain against mouse-implanted sarcoma 180 and Ehrlich-carcinoma solid tumor

The D-mannan of Saccharomyces cerevisiae X2180-1A-5 mutant strain, which possesses a main chain composed of alpha-(1 yields 6) linked D-mannopyranosyl residues and a small proportion of branches composed of alpha-(1 yields 2)- and alpha-(1 yields 3)-linked D-mannopyranosyl residues, showed strong growth-inhibitory activity against mouse-implanted Sarcoma 180 and Ehrlich-carcinoma solid tumor. The observation that the level of this activity was nearly identical with that of the D-mannan of a wild-type strain of bakers' yeast, which possesses a high proportion of branches composed of alpha-(1 yields 2)-and alpha-(1 yields 3)-linked D-mannopyranosyl residues, suggests that the branches are not essential for antitumor activity. The partial acid-degradation products of both D-mannans, the molecular weight of which was one-third of that of each parent D-mannan, had only one half of the antitumor activity of the parent D-mannans. This suggests that molecular size is the most important factor for the differences in acitvity of the polysaccharides of wild and mutant strains.

Relationship between phosphate content and immunochemical properties of subfractions of bakers' yeast mannan

The mannan of bakers' yeast (Saccharomyces cerevisiae) was fractionated on a column of diethylaminoethyl-Sephadex into five subfractions. Phosphate content of these mannan subfractions was proportional to the concentration of NaCl solutions used in the chromatographic separation. Quantitative precipitin reactions showed that the serological reactivities of the subfractions were proportional to the content of phosphate. The result of acetolysis study showed that the amounts of mannotetraose and phosphate-containing oligosaccharide fractions increased proportionally to the acidity, whereas the amount of mannose decreased inversely. The results from quantitative precipitin reaction tests and acetolysis study demonstrated that both phosphate contents and multiplicity of branching moieties of mannan subfractions increased proportionally, i.e., micro-heterogeneity concerning the acidity comprised in the parent bulk mannan is not attributable merely to the coexistence of molecular species containing different amounts of phosphate but also to the presence of more of the branching moieties.