Chemical and enzymatic changes in the cell walls of Candida albicans and Saccharomyces cerevisiae by scanning electron microscopy

Abstract

Candida albicans and Saccharomyces cerevisiae cells were examined by scanning electron microscopy before and after extraction of the mannans of the cell wall. The surfaces of control cells were smooth; after mannan extraction they were rough and showed erosions which were particularly striking within the area of the scars. Helicase digested irregular holes through the cell wall within 20 min; these increased in size during an additional 40 min of digestion. These holes were not localized in or on the bud scars, which remained intact even after the long digestion period. The results were used to construct a model for yeast cell wall structure.

A comparative study of the incorporation of a 1,6-ss-glucan and an O-glycosylated protein epitope into the cell wall of Candida albicans

“…The primary reason for choosing these epitopes was that we expected them to be localized in different layers within the cell-wall structure. The Incorporation of epitopes in the C. albicans wall accepted model for the cell wall of C. albicans consists of an inner layer of fibrillar material that includes glucan and chitin, together with some mannoproteins and an outer amorphous mannoprotein layer (Horisberger 8r Vonlanthen, 1977 ;Koch & Rademacher, 1980;Zlotnik et a/., 1984).…”

Chlorine Dioxide (CLO2) As a Non-Toxic Antimicrobial Agent for Virus, Bacteria and Yeast (Candida Albicans)

“…[25][26][27][28][29][30][31][32][33][34][35][36] This fungus is usually found in the Y-form in normal healthy individuals. [36] The association of the M-form with pathogenicity is based on the premise that hyphae (filaments) penetrate tissues more readily than yeast cells and are more difficult to phagocytose [35]. Figure 10 illustrated differences in morphology in spore development at two different temperatures; 20° and 37°C.…”

Identification of a mannoprotein present in the inner layer of the cell wall of Saccharomyces cerevisiae

“…It consists of a layered structure, with an internal layer made up of ␤-1,3 and ␤-1,6 glucans, small amounts of chitin and mannoproteins, and an outer layer of mannoproteins (13, 23). The inner layer is responsible for the shape and mechanical strength of the wall (19,24,50), while the outer mannoprotein layer determines the surface properties of the cell, such as hydrophobicity, electrical charge, flocculence, and sexual agglutinability, as well as limiting the porosity of the cell wall (8-10, 50).The mannoproteins can be divided into three groups according to the methods used for their extraction from the cell wall: sodium dodecyl sulfate (SDS)-extractable mannoproteins (44), glucanase-extractable mannoproteins, which can be released only after glucanase digestion of the glucan layer (31,44,47), and mannoproteins extractable by reducing agents (35). The glucanase-extractable mannoproteins identified so far have two common characteristics: one is a high serine/threonine content (up to 50% of the C-terminal half of the protein), and the other is the presence of a putative glycosylphosphatidylinositol (GPI) attachment site (23,46).…”

“…It consists of a layered structure, with an internal layer made up of ␤-1,3 and ␤-1,6 glucans, small amounts of chitin and mannoproteins, and an outer layer of mannoproteins (13, 23). The inner layer is responsible for the shape and mechanical strength of the wall (19,24,50), while the outer mannoprotein layer determines the surface properties of the cell, such as hydrophobicity, electrical charge, flocculence, and sexual agglutinability, as well as limiting the porosity of the cell wall (8-10, 50).…”