Evaluation of a gold-silver staining method for detection and identification ofCandida species by light microscopy

Abstract

A gold-silver staining procedure was evaluated for detection of Candida species of medical importance. Probes were prepared by coupling lectins or antibodies (polyclonal and monoclonal) directly or indirectly to colloidal gold particles. Structures reacting to these probes were specifically revealed by light microscopy in cells present in infected kidney tissue sections or in isolated yeast cells on glass slides. Definition, contrast and sensitivity were of a high order. Preliminary data showed that it was possible, using discriminating dilutions, to identify cells from different species of the genus Candida, grown in vitro, according to their ability to stain with polyclonal monospecific antisera. The advantages of gold-silver staining compared with other staining procedures currently used in routine mycological laboratories are its sensitivity, good definition, ease and rapidity, and long conservation of reaction. It is suggested that the procedure has applications for research and identification of yeasts in clinical samples.

Ultrastructural immunodetection of a Pichia anomala killer toxin: a preliminary study

“…The amount of gold particles observed through the cell wall layers was not enough, however, to permit an accurate description of the toxin secretion modalities. Experimental reproducibility and remarkable labeling of well preserved cellular ultrastructures might be achieved by direct IEM assays, mAb KT4 will be linked to colloidal gold particles and used to detect the toxin secretion in killer yeast cells embedded in Lowicryl resin by IEM or by immunogold-siiver staining on yeast cells dried on glass slides [3]. Preliminary results in indirect IEM have already shown greater fixation of mAb KT4 in the cell wall of Lowicryl embedded killer yeast cells (unpublished data).…”

Carbohydrate profiling of fungal cell wall surface glycoconjugates of Trichophyton tonsurans and other keratinophilic filamentous fungi using lectins

“…Lectin-fungal cell wall carbohydrate interaction has been demonstrated in several species of medical impor- These studies have shown that most fungi exhibit N-acetyl-D-glucosamine and glucose ⁄ mannose on the cell surface, as inferred by the WGA and Con A binding, respectively. [11][12][13][14][15] Using lectins conjugated with fluorescein isothiocyanate, Robin et al [16] described lectin staining patterns in A. fumigatus and F. solani isolated from cases of eye infections. WGA, UEA-I and Con A intensely stained all the species, whereas PNA did not.…”

“…The role of lectins in mycological diagnosis has been reviewed in detail by several authors. 2,3,[11][12][13][14][15][16] Despite the advantages, the development of effective test based on lectin typing will remain difficult until some degree of standardisation of procedures is agreed. Reported specificities of lectins vary depending on the source consulted.…”

“…Lectin‐fungal cell wall carbohydrate interaction has been demonstrated in several species of medical importance such as Aspergillus fumigatus , Candida albicans , Cryptococcus neoformans , F. solani and Paracoccidioides brasiliensis . These studies have shown that most fungi exhibit N ‐acetyl‐ d ‐glucosamine and glucose/mannose on the cell surface, as inferred by the WGA and Con A binding, respectively 11–15 …”

Immunohistologic diagnosis of systemic mycoses: An update

“…capsuIatum, regardless of serotype. Adsorption of labeled antibodies produced against the most complete H. capsulatum serotype (serotype 1,2,3,4) with cells of Candida albicans yielded a conjugate that stained only //. capsulatum vat capsulatum, I-I.…”