Aqueous synthesis of highly luminescent glutathione-capped Mn²⁺-doped ZnS quantum dots.

In this paper, an aqueous-based route has been developed to prepare highly luminescent glutathione (GSH)-capped Mn-doped ZnS quantum dots (QDs). The dots obtained have an average diameter of 4.3 nm and exhibit the Mn(2+)-related orange luminescence with very low surface defect density.

Glycosylated quantum dots for the selective labelling of Kluyveromyces bulgaricus and Saccharomyces cerevisiae yeast strains.

Highly fluorescent CdTe quantum dots (QDs) stabilized by thioglycolic acid (TGA) were prepared by an aqueous solution approach and used as fluorescent labels in detecting yeast cells. Sugars (mannose, galactose or glucose) were adsorbed on CdTe@TGA QDs and the interaction of these nanoparticles with yeast cells was studied by fluorescence microscopy. Results obtained demonstrate that galactose and mannose functionalized QDs associate respectively with Kluyveromyces bulgaricus and Saccharomyces cerevisiae yeast strains due to saccharide/lectin specific recognition.

Development of a fluorescence-based microtiter plate method for the measurement of glutathione in yeast.

The present work was aimed to the development of a fluorescence assay using the universal 96-well microplate format, for the measurement of reduced glutathione (GSH) in yeast cells. The method relies upon the reaction between GSH and a highly selective fluorogenic probe, i.e.

Potential relationship between glutathione metabolism and flocculation in the yeast Kluyveromyces lactis.

Reduced glutathione (GSH) is involved in biochemical and physiological processes in cells. Flocculation is an important mechanism in microorganisms. The present study concerned the potential relationship between GSH metabolism and flocculation.

Enhanced cellular uptake of a glutathione selective fluorogenic probe encapsulated in nanoparticles.

Selective fluorogenic probes for the labelling of intracellular reduced glutathione (GSH), i.e. ortho-phthaldialdehyde (OPA) and naphthalene-2,3-dicarboxaldehyde (NDA), have been encapsulated in polymeric nanoparticles (NPs) and the ability of the NPs to enhance uptake of the probe by microbial cells has been evaluated.

Morphological specificity of yeast and filamentous Candida albicans forms on surface properties.

Physicochemical surface properties of Candida albicans were assessed from microbial adhesion to human epithelial cells and to octane droplets. The adherence of cells demonstrated the occurrence of morphological specificity for these adhesion assays. Filamentous forms exhibited adherence third times higher compared to budding forms, while their electrophoretic mobilities were comparable.

Assessment of in situ cellular glutathione labeling with naphthalene-2,3-dicarboxaldehyde using high-performance liquid chromatography.

We have presently studied a dialdehydic reagent, i.e. naphthalene-2,3-dicarboxaldehyde (NDA), as a fluorogenic probe for the labeling of intracellular reduced glutathione (GSH), using a yeast strain Candida albicans as a cell model.

Fluorescence and infrared spectrometric study of cell walls from Candida, kluyveromyces, Rhodotorula and schizosaccharomyces yeasts in relation with their chemical composition.

Composition, level, and arrangement of the structural polysaccharides determine biophysical properties of fungal cell walls. A small amount of a beta(1-->4) linear homopolymer of GlcNAc in the cell wall forms chitin. To study the components of the cell walls and to estimate the quantity of chitin for different strains, two spectroscopic methods were applied.

1,2,4-Triazolo mercapto and aminonitriles as potent antifungal agents.

A series of 3-mercapto-1,2,4-triazoles mono or disubstituted at 2-, 3- or 4-positions were synthesized and evaluated as antifungal agents. Many of these derivatives exhibit high activity against Candida albicans and Candida tropicalis.

Relation between cell wall chitin content and susceptibility to amphotericin B in Kluyveromyces, Candida and Schizosaccharomyces species.

Yeast strains belonging to the genera Candida, Kluyveromyces and Schizosaccharomyces were tested for their susceptibility (or resistance) to amphotericin B (AmB) in relation to their cell wall chitin content. Results showed that membrane sterol contents did not enable us to explain resistance or susceptibility of these yeasts to AmB. Indeed, we noted that resistant strains were as rich in ergosterol as sensitive strains.

Effect of sodium orthovanadate on glycosylation of the phosphopeptidomannans involved in the cell-cell aggregation of the yeast Kluyveromyces bulgaricus.

In studies of yeast flocculation it has been found that low concentrations of vanadium contained in sodium orthovanadate do not affect the growth and the cell-cell adhesion of the yeast Kluyveromyces bulgaricus, whereas high concentrations delay the growth of the yeasts and strongly inhibit flocculation. Moreover, higher sensitivity to Hygromycin B and calcofluor white was taken to imply altered cell wall integrity which is supported by compositional analysis of the extracted phosphopeptidomannans. Yeasts grown on sodium orthovanadate show a decrease in the percentage of phosphopeptidomannans and their compositions.

Change of cell wall chitin content in amphotericin B resistant Kluyveromyces strains.

The culture of two Kluyveromyces species, Kluyveromyces lactis (ATCC 96897) and Kluyveromyces bulgaricus (ATCC 96631), in the presence of subinhibitory doses of amphotericin B leads to the selection of mutants which are resistant to this polyene. The mutants show an alteration of their cell wall composition with the main change corresponding to an increase of chitin. The enzyme activities involved in the metabolism of this polymer, i.

Molecular recognition by Kluyveromyces of amphotericin B-loaded, galactose-tagged, poly (lactic acid) microspheres.

In an effort to develop a new way of drug delivery, especially for polyenic antifungal molecules, we have incorporated amphotericin B (AmB) into biodegradable galactosylated poly (L-lactic acid) (L-PLA) and poly (L-lactic-co-glycolic acid) (PLGA) microspheres. These drug carriers were prepared by solvent evaporation using an oil/water (o/w) emulsion. The ratio of galactosyl spacers with different chain lengths was 1.