Use of tannic acid as a fixative-mordant to improve the ultrastructural appearance of<i>Candida albicans</i>blastospores

“…Other workers who have used aldehyde fixation plus 0s-mium postfixation also observed electron-lucent walls with an outer electron-dense layer (Cassone et al 1973;Drewe 1981;Persi and Burnham 1981). In contrast, fixation with permanganate revealed up to five layers in the cell wall of C .…”

Section: Cell Sur$ace Effects Associated With Germ Tube Formationmentioning

confidence: 80%

“…Tronchin and colleagues (1981) provided evidence for a fuzzy coat using an indirect concanavalin A -peroxidase or femtin technique on frozen sections of cell pellets. Persi and Burnham (1981) also demonstrated the presence of a fuzzy outer layer when tannic acid was used as a fixative-mordant.…”

Section: Cell Sur$ace Effects Associated With Germ Tube Formationmentioning

confidence: 98%

Morphological studies of N-acetylglucosamine induced germ tube formation by Candida albicans

Hubbard¹,

Sullivan²,

Shepherd³

1985

Can. J. Microbiol.

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In N-acetylglucosamine induced germ tube formation by Candida albicans, multiple (up to five) protuberances appeared within 90 min at 37 degrees C on each yeast cell. The protuberances were extensions of the cytosol and contained vesiclelike structures. Usually only one protuberance subsequently developed into a germ tube. The germ tubes emanated from all aspects of the cell surface but seldom from the budding (long axis) poles. Pseudohyphae, which originated from the budding pole, exhibited a marked constriction at the site of emergence and were 0.6-2.5 microns in diameter compared with a diameter of 0.6-0.8 micron for germ tubes. The presence of septa confirmed that germ tubes are precursors of septate mycelia. Ultrathin-section transmission electron microscopy of aldehyde plus osmium fixed cells revealed electron-lucent walls with a thin electron-dense outer layer. A fibrillar border was also routinely associated with germ tubes. Poststaining with potassium permanganate revealed, in addition, a previously invisible fuzzy layer on the outer region of the cell wall which extended over bud scars and germ tubes and which coalesced at sites of contact between cells.

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“…The ultrastructural images of the cell walls of Candida have revealed a multilayered arrangement (FarkaS, 1979 ;Wessels & Sietsma, 1981), although the number of layers may vary with fixation procedure and thus range from 5 to 8 layers (Djaczenko & Cassone, 1971 ;Cassone et al, 1973;Persi & Burnham, 1981 ;Poulain et al, 1978Poulain et al, , 1981. Interpretation of this stratification is difficult due to artifacts inherent in electron microscopic methods (Wessels & Sietsma, 198 1) and because contrast differences resulting from selective retention of electron-dense stains may not reflect actual chemical differences in the layers (Garrison, 1981).…”

Section: Discussionmentioning

confidence: 99%

“…As a control for Au-WGA labelling, yeast cells fixed in the G-0-T-0-U (glutaraldehyde, osmium, tannic acid, osmium, uranyl acetate) procedure (Persi & Burnham, 1981) were sectioned, labelled with Au-WGA, and examined as stated above.…”

Section: Introductionmentioning

confidence: 99%