Fixed points for non-surjective expansion mappings

The contractive conditions of Popa (Demonstr. Math. 1990, 23, 213-218) were further improved for four non-surjective expansion mappings, and some common fixed point theorems under semi-compatible pairs of mappings are proved. Our main findings bring improvements to a number of results in the non-metric setting. Some implications for mathematical physics are raised with respect to physical invariant

Isolation and biochemical characterization of cell wall tight protein complex involved in self-flocculation of Kluyveromyces bulgaricus.

International audienceFlocculation of yeasts is a cell-cell aggregation phenomenon which is driven by interactions between cell wall lectins and cell wall heteropolysaccharides. In Sabouraud medium, Kluyveromyces bulgaricus was highly flocculent. Incubation of flocculent K. bulgaricus cells with EDTA or Hecameg led to extracts showing hemagglutinating and flocculating properties. Purification of the extracts by native PAGE gave two bands which allowed flocculation of deflocculated K. bulgaricus. Both bands with specific reflocculating activity were composed of five subunits, of which only three possessed weak reflocculating activity upon deflocculated yeast. The mixture of these three proteins allow the recovery of initial specific reflocculating activity of the complex. These three proteins, denoted p28, p36 and p48, presented, in their first 15 amino acids, homologies with glycolysis enzymes, i.e., 3-phosphoglycerate mutase, glyceraldehyde-3-phosphate dehydrogenase and enolase, respectively. However, no such enzymatic activity could be detected in the crude extract issued from treatment with EDTA and Hecameg of flocculent yeast cells. When yeasts had grown in glucose poor medium, flocculation was drastically affected. The EDTA and Hecameg crude extracts showed weak reflocculating activity. After PAGE, the protein complexes did not appear in the EDTA extract, but they did appear in the Hecameg crude extract. These results suggest that: (i) self-flocculation of K. bulgaricus depends on the expression of different floc-forming protein complex, (ii) these proteins are galactose specific lectins showing homologies in their primary structure with glycolysis enzymes.Flocculation of yeasts is a cell-cell aggregation phenomenon which is driven by interactions between cell wall lectins and cell wall heteropolysaccharides. In Sabouraud medium, Kluyveromyces bulgaricus was highly flocculent. Incubation of flocculent K. bulgaricus cells with EDTA or Hecameg led to extracts showing hemagglutinating and flocculating properties. Purification of the extracts by native PAGE gave two bands which allowed flocculation of deflocculated K. bulgaricus. Both bands with specific reflocculating activity were composed of five subunits, of which only three possessed weak reflocculating activity upon deflocculated yeast. The mixture of these three proteins allow the recovery of initial specific reflocculating activity of the complex. These three proteins, denoted p28, p36 and p48, presented, in their first 15 amino acids, homologies with glycolysis enzymes, i.e., 3-phosphoglycerate mutase, glyceraldehyde-3-phosphate dehydrogenase and enolase, respectively. However, no such enzymatic activity could be detected in the crude extract issued from treatment with EDTA and Hecameg of flocculent yeast cells. When yeasts had grown in glucose poor medium, flocculation was drastically affected. The EDTA and Hecameg crude extracts showed weak reflocculating activity. After PAGE, the protein complexes did not appear in the EDTA extract, but they did appear in the Hecameg crude extract. These results suggest that: (i) self-flocculation of K. bulgaricus depends on the expression of different floc-forming protein complex, (ii) these proteins are galactose specific lectins showing homologies in their primary structure with glycolysis enzymes

Sterol and Fatty Acid Composition of Candida lusitaniae Clinical Isolates

The sterol and fatty acid compositions of four amphotericin B-resistant and of two amphotericin B-susceptible Candida lusitaniae clinical isolates were determined. A flow cytofluorometric susceptibility test (FCST) with a membrane potential-sensitive cationic dye was used as a complement to the conventional method for selecting the isolates. Compared to susceptible isolates, resistant ones showed a greatly reduced ergosterol content and changes in sterol composition, consistent with a defect in Δ8→7 isomerase. Within each group, no correlation between the sterol or fatty acid pattern or composition and both the degree of in vitro susceptibility and FCST MIC was found

Chemical modification and stability of the cell wall phosphopeptidomannans of flocculent and weakly flocculent Kluyveromyces bulgaricus cells

International audienc

Synthesis of new oligosaccharidyl-thio-β-cyclodextrins (CDS): A novel family of potent drug-targetting vectors

International audienc