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Fungal Adhesion (fungal + adhesion)
Selected AbstractsHIV protease inhibitors attenuate adherence of Candida albicans to epithelial cells in vitroFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1 2001Jasmin Bekti Abstract Oropharyngeal candidiasis is one of the first and most commonly reported opportunistic infections of untreated AIDS patients. With the introduction of the new antiviral HAART therapy, including HIV protease inhibitors, this mucocutaneous infection is nowadays only rarely observed in treated patients. It was recently shown that HIV protease inhibitors have a direct attenuating effect on Candida albicans secreted aspartic proteinases (Saps), an investigation prompted by the fact that both Sap and HIV protease belong to the superfamily of aspartic proteinases and by the observation that mucocutaneous infections sometimes resolve even in the absence of an immunological improvement of the host. As these Saps are important fungal virulence factors and play a key role in adhesion to human epithelial cells we tried to assess the effect of the HIV protease inhibitors Ritonavir, Indinavir and Saquinavir on fungal adhesion to these cells. The effect on phagocytosis by polymorphonuclear leukocytes was also assessed. Ritonavir was found to be the most potent inhibitor of fungal adhesion. A dose-dependent inhibition of adhesion to epithelial cells was found already at 0.8 ,M and was significant at 4 ,M or higher, at 500 ,M the inhibition was about 55%. Indinavir and Saquinavir inhibited significantly at 4 ,M or 20 ,M, respectively; at 500 ,M the inhibition was 30% or 50%. In contrast, no protease inhibitor was able to modulate phagocytosis of Candida by polymorphonuclear leukocytes. In conclusion, inhibition of Saps by HIV protease inhibitors may directly help to ease the resolution of mucosal candidiasis. In future, derivatives of HIV protease inhibitors, being more specific for the fungal Saps, may form an alternative in the treatment of mucosal candidiasis insensitive to currently available antimycotics. [source] Phenotypic diversity of Flo protein family-mediated adhesion in Saccharomyces cerevisiaeFEMS YEAST RESEARCH, Issue 2 2009Sebastiaan E. Van Mulders Abstract The Saccharomyces cerevisiae genome encodes a Flo (flocculin) adhesin family responsible for cell,cell and cell,surface adherence. In commonly used laboratory strains, these FLO genes are transcriptionally silent, because of a nonsense mutation in the transcriptional activator FLO8, concealing the potential phenotypic diversity of fungal adhesion. Here, we analyse the distinct adhesion characteristics conferred by each of the five FLO genes in the S288C strain and compare these phenotypes with a strain containing a functional copy of FLO8. Our results show that four FLO genes confer flocculation, but with divergent characteristics such as binding strength, carbohydrate recognition and floc size. Adhesion to agar surfaces, on the other hand, largely depended on two adhesins, Flo10 and Flo11. Expression of any FLO gene caused a significant increase in cell wall hydrophobicity. Nevertheless, the capacity to adhere to plastic surfaces, which is believed to depend on hydrophobic interactions, differed strongly between the adhesins. Restoring Flo8 yielded both flocculation and cell,surface adherence, such as invasive growth, a phenotype not observed when any of the single FLO genes was overexpressed. Taken together, this study reveals how S. cerevisiae carries a small reservoir of FLO genes that allows cells to display a wide variety of adhesive properties. [source] Analysis of the Paracoccidioides brasiliensis triosephosphate isomerase suggests the potential for adhesin functionFEMS YEAST RESEARCH, Issue 8 2007Luiz Augusto Pereira Abstract Paracoccidioides brasiliensis is an important fungal pathogen. The disease it causes, paracoccidioidomycosis (PCM), ranges from localized pulmonary infection to systemic processes that endanger the life of the patient. Paracoccidioides brasiliensis adhesion to host tissues contributes to its virulence, but we know relatively little about molecules and the molecular mechanisms governing fungal adhesion to mammalian cells. Triosephosphate isomerase (TPI: EC 5.3.1.1) of P. brasiliensis (PbTPI) is a fungal antigen characterized by microsequencing of peptides. The protein, which is predominantly expressed in the yeast parasitic phase, localizes at the cell wall and in the cytoplasmic compartment. TPI and the respective polyclonal antibody produced against this protein inhibited the interaction of P. brasiliensis to in vitro cultured epithelial cells. TPI binds preferentially to laminin, as determined by peptide inhibition assays. Collectively, these results suggest that TPI is required for interactions between P. brasiliensis and extracellular matrix molecules such as laminin and that this interaction may play an important role in the fungal adherence and invasion of host cells. [source] Flocculation, adhesion and biofilm formation in yeastsMOLECULAR MICROBIOLOGY, Issue 1 2006Kevin J. Verstrepen Summary Yeast cells possess a remarkable capacity to adhere to abiotic surfaces, cells and tissues. These adhesion properties are of medical and industrial relevance. Pathogenic yeasts such as Candida albicans and Candida glabrata adhere to medical devices and form drug-resistant biofilms. In contrast, cell,cell adhesion (flocculation) is a desirable property of industrial Saccharomyces cerevisiae strains that allows the easy separation of cells from the fermentation product. Adhesion is conferred by a class of special cell wall proteins, called adhesins. Cells carry several different adhesins, each allowing adhesion to specific substrates. Several signalling cascades including the Ras/cAMP/PKA and MAP kinase (MAPK)-dependent filamentous growth pathways tightly control synthesis of the different adhesins. Together, these pathways trigger adhesion in response to stress, nutrient limitation or small molecules produced by the host, such as auxin in plants or NAD in mammals. In addition, adhesins are subject to subtelomeric epigenetic switching, resulting in stochastic expression patterns. Internal tandem repeats within adhesin genes trigger recombination events and the formation of novel adhesins, thereby offering fungi an endless reservoir of adhesion properties. These aspects of fungal adhesion exemplify the impressive phenotypic plasticity of yeasts, allowing them to adapt quickly to stressful environments and exploit new opportunities. [source] Experimental superficial candidiasis on tissue modelsMYCOSES, Issue 4 2010J. A. M. S. Jayatilake Summary Candida species are common pathogens causing superficial mycoses primarily affecting the mucosa and the skin in humans. Crucial steps during pathogenesis of superficial candidiasis comprise fungal adhesion, colonisation and subsequent penetration of the respective tissues. Exploring these pathological events and perhaps fungal and tissue responses towards drug treatment is imperative in the management of this infection. Unfortunately, pathological biopsies of superficial candidiasis do not exhibit the early changes in the host,pathogen interaction as the tissues are already invaded by the fungi. In vivo experimental assessments of pathological processes of superficial candidiasis are also limited because of the difficulties in providing reproducible and comparable conditions in the host environment. Conversely, in vitro models have helped studying fungal,host interactions under more defined and controlled conditions. Some common in vitro models used to simulate superficial candidiasis are chick chorioallantoic membrane, mucosal explants and single layer or multiple layer cell cultures. Interestingly, these experimental approaches share advantages as well as disadvantages when compared with in vivo conditions. Hence, this review intends to discuss about the experimental superficial candidiasis produced in various tissue models and their advantages as well as disadvantages with a particular reference to further improvement of validity and reliability of such experiments. [source] | |||||||||||||