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Fungal Invasion (fungal + invasion)
Selected AbstractsCurrent knowledge of host response in human tineaMYCOSES, Issue 4 2009J. Brasch Summary Skin infection caused by dermatophytes is called tinea. In this short review, the known mechanisms and factors involved in human tinea and important for the host response are briefly delineated. To establish tinea, fungal propagules must attach to the skin, germinate and overcome the epidermal barrier. Keratinases and other enzymes are released in this process and host keratinocytes are activated. This is followed by an inflammatory response mediated by a plentitude of cytokines and receptors, comprising innate as well as acquired immunity, including neutrophilic granulocytes, macrophages, antibodies and T cells. Cellular defence mechanisms appear to be decisive for clearing of infection. Nails and hair follicles are the particular sites often invaded by dermatophytes that show distinctive patterns of infection. Nails are largely excluded from defence mechanisms and steroid hormones of the pilosebaceous units may have a particular effect on follicular infection. Fungal invasion of the dermis can cause granulomatous reactions. Immune reactions to dermatophytes may lead to sterile eruptions distant from the infected skin areas. [source] IL-1,, IL-1ra and IL-8 are differentially induced by Candida in experimental oral candidiasisORAL DISEASES, Issue 4 2007JAMS Jayatilake Objective:, To investigate the expression of interleukin-1, (IL-1,), IL-1ra and IL-8 by the oral epithelium challenged by various Candida species. Materials and methods:,In vitro candidiasis was induced by C. albicans wild type SC5314, its EFG1, CPH1 and secretory aspartyl proteinase (SAP) mutants and, ATCC isolates of C. albicans, C. tropicalis and C. dubliniensis using a reconstituted human oral epithelium (RHOE) model. IL-1,, IL-1ra and IL-8 levels in culture media were quantified by an enzyme-linked immunosorbent assay at 12, 24 and 48 h. Fungal invasion and IL-1ra expression in RHOE were detected by periodic acid-Schiff staining and immunohistochemistry. Results:, Overall, the invasive Candida induced relatively higher levels of IL-1,, IL-1ra and IL-8 in the culture media than the noninvasive isolates. IL-1, and IL-1ra levels induced by Candida with hyphal invasion were significantly higher (P < 0.05) than those induced by the isolates without hyphal invasion at 12, 24 and 48 h. Candida albicans SC5314 induced IL-1ra expression in RHOE at 12 and 24 h but not at 48 h consistent with its hyphal invasion; while the noninvasive mutants and non- albicans Candida induced IL-1ra expression at 48 h. Conclusions:, The cytokine expression profiles in experimental oral candidiasis may be associated with the invasive potential of Candida. [source] Frozen in time: a new method using cryo-scanning electron microscopy to visualize root,fungal interactionsNEW PHYTOLOGIST, Issue 2 2006Steve Refshauge Summary ,,A new method of sample preparation for cryo-scanning electron microscopy was used to visualize internal infection of wheat (Triticum aestivum) roots by the pathogenic fungus Rhizoctonia solani AG-8. The new method retained fungal hyphae and root cells in situ in disintegrating root tissues, thus avoiding the distortions that can be introduced by conventional preparation by chemical fixation, dehydration and embedding. ,,Infected roots frozen in liquid nitrogen were cryo-planed and etched (sublimed) at ,80°C for a critical length of time (up to 9 min) in the microscope column to reveal plant and fungal structures in three dimensions. ,,Root and fungal structures were well preserved irrespective of infection severity. Root and hyphal cell walls were clearly seen and hyphal architecture within and between root cells was preserved. ,,This rapid method permits three-dimensional in situ visualization of fungal invasion within roots and has broad application for examination of diseases caused by other necrotrophic fungi. [source] Maize mutants affected at distinct stages of the arbuscular mycorrhizal symbiosisTHE PLANT JOURNAL, Issue 2 2006Uta Paszkowski Summary Maize mutants affected in the symbiotic interaction with the arbuscular mycorrhizal fungus Glomus mosseae have been found by a visual, macroscopic screen in a Mutator -tagged population of maize. Seven mutants have been identified, falling into three phenotypic classes. For each class one mutant has been characterized in more detail. The nope1 (noperception 1) mutant does not support appressoria formation of G. mosseae, suggesting the absence of a plant-encoded function necessary for early recognition prior to contact. The phenotype segregated as a monogenic recessive trait, indicating that a mutation in a single locus abolished compatibility of maize to G. mosseae. On a second mutant termed taci1 (taciturn 1), appressoria form at reduced frequency but their morphology is normal and leads to penetration of the rhizodermis. However, intraradically, the majority of hyphae are septate, resulting in terminated fungal spreading. This phenotype suggests that the mutation of taci1 has an effect on recognition and on cortex invasion. Segregation analysis indicates taci1 to carry a recessive mutation. In contrast, wild-type fungal morphology has been recorded in the Pram1 (Precocious arbuscular mycorrhiza 1) mutant, which displays enhanced and earlier fungal invasion. This trait segregates in a dominant fashion indicative of a gain-of-function mutation affecting the plant's control over restricting fungal colonization. [source] Invasion of Cryptococcus neoformans into human brain microvascular endothelial cells requires protein kinase C-, activationCELLULAR MICROBIOLOGY, Issue 9 2008Ambrose Jong Summary Pathogenic fungus Cryptococcus neoformans has a predilection for the central nervous system causing devastating meningoencephalitis. Traversal of C. neoformans across the blood,brain barrier (BBB) is a crucial step in the pathogenesis of C. neoformans. Our previous studies have shown that the CPS1 gene is required for C. neoformans adherence to the surface protein CD44 of human brain microvascular endothelial cells (HBMEC), which constitute the BBB. In this report, we demonstrated that C. neoformans invasion of HBMEC was blocked in the presence of G109203X, a protein kinase C (PKC) inhibitor, and by overexpression of a dominant-negative form of PKC, in HBMEC. During C. neoformans infection, phosphorylation of PKC, was induced and the PKC enzymatic activity was detected in the HBMEC membrane fraction. Our results suggested that the PKC, isoform might play a crucial role during C. neoformans invasion. Immunofluorescence microscopic images showed that induced phospho-PKC, colocalized with ,-actin on the membrane of HBMEC. In addition, cytochalasin D (an F-filament-disrupting agent) inhibited fungus invasion into HBMEC in a dose-dependent manner. Furthermore, blockage of PKC, function attenuated actin filament activity during C. neoformans invasion. These results suggest a significant role of PKC, and downstream actin filament activity during the fungal invasion into HBMEC. [source] | |||||||||||||