Lipolytic activity of some dermatophytes. II. Isolation and characterisation of the lipase of Epidermophyton floccosum.
TL;DR: The physicochemical properties, stability and localisation of lipase from the anthropophilic dermatophyte Epidermophyton floccosum have been investigated and neither the skin-surface lipids nor the body temperature of man significantly affected the activity of the lipase.
Abstract: SUMMARY. The physicochemical properties, stability and localisation of lipase from the anthropophilic dermatophyte Epidermophyton floccosum have been investigated. The lipase was best secreted by older cultures at an optimum pH of 6·5–7 in the temperature range 40–45·C. Neither the skin-surface lipids nor the body temperature of man significantly affected the activity of the lipase.
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TL;DR: New genetic tools were recently developed, allowing a more rapid and high-throughput functional investigation of dermatophyte genes and the identification of new putative virulence factors, which will open the way to a more comprehensive view of the interactions between these fungi and host epidermal cells, especially keratinocytes.
Abstract: Despite the superficial localization of most dermatophytosis, host-fungus relationship in these infections is complex and still poorly elucidated. Though many efforts have been accomplished to characterize secreted dermatophytic proteases at the molecular level, only punctual insights have been afforded into other aspects of the pathogenesis of dermatophytosis, such as fungal adhesion, regulation of gene expression during the infection process, and immunomodulation by fungal factors. However, new genetic tools were recently developed, allowing a more rapid and high-throughput functional investigation of dermatophyte genes and the identification of new putative virulence factors. In addition, sophisticated in vitro infection models are now used and will open the way to a more comprehensive view of the interactions between these fungi and host epidermal cells, especially keratinocytes.
190 citations
Cites background from "Lipolytic activity of some dermatop..."
...In contrast, little information is available about other hydrolases, such as lipases and a ceramidase, produced by these fungi [19, 20]....
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TL;DR: The morphology of the fungal elements, such as arthroconidia and hyphae, during the adhesion and invasion stages of the dermatophyte are followed to show their mechanical and biochemical capabilities to invade the skin tissue effectively.
Abstract: Dermatophytes are pathogenic fungi that infect human skin, nails and hair and cause dermatophytosis. Trichophyton mentagrophytes is one of the most widespread species that belong to this group. Infection of the skin tissues include several stages, i.e., adhesion to the surface of the skin, invasion into the sublayers by the penetration of fungal elements and secretion of enzymes that degrade the skin components. In this study we have followed the morphology of the fungal elements, such as arthroconidia and hyphae, during the adhesion and invasion stages. Skin explants were inoculated with the dermatophyte and observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Skin explants were also inoculated with a transgenic isolate of T. mentagrophytes expressing the green fluorescent protein (GFP). The infected sublayers were investigated by confocal scanning laser microscopy (CSLM). As an adaptation to the tissue environment, the dermatophyte produced long fibrils when it is on the open surface of the stratum corneum, while short and thin fibrils are produced inside the dense sublayers. The short and long projections might have a role in adhesion. Invasion may be produced by mechanical and biochemical means. Invasion of the tissue showed hyphal branching and growth in multiple directions. The proteolytic profile was assayed by substrate gel and proteolytic activity. Two serine proteases of similar molecular weight were secreted during growth on the epidermal matrix components keratin and elastin. The dermatophyte may use the proteolytic enzymes to invade the surface and also the deep layer of the skin in immunocompromised patients. Dermatophytes, which are well adapted infectious agents, seem to use their mechanical and biochemical capabilities to invade the skin tissue effectively.
80 citations
TL;DR: The present review is aimed at discussing the newer advances in the understanding of the pathogenesis of various clinical types of OM apart from the newer and exciting techniques of diagnosing it.
Abstract: Onychomycosis (OM) is the commonest disorder affecting the nail unit. The fact that it affects 3-26% people worldwide goes to show that it is a significant health problem. The prevalence of OM has been reported to be increasing over the years. Although, we know much about various predisposing factors, we are yet unclear about its exact pathogenesis. The peculiarities of the nail unit with respect to its structure and its immune mechanisms make OM an adversary, which once established is difficult to eradicate. There have been many recent advances in our understanding of the pathogenesis of OM and our methods of diagnosing it. The increasingly valuable role of histopathology; refinements in its technique; PCR techniques; Optical coherence tomography and advances in spectrometric techniques have been reported. The present review is aimed at discussing the newer advances in our understanding of the pathogenesis of various clinical types of OM apart from the newer and exciting techniques of diagnosing it.
44 citations
TL;DR: The present review will bring out the differences or similarities of lipid metabolism in diverse fungal species and each section will deal, comparatively, with various aspects of fungal lipid metabolism and physiology.
Abstract: So far, reviews that have appeared on fungal lipids present data mainly on the lipid composition of these organisms and the influence of lipids on their physiology. These reviews provide little information about the enzymes of lipid metabolism in these organisms and it is assumed, by most workers, that lipid synthesis in all fungi takes place as in Saccharomyces cervesiae, the only fungus in which the complete pathways of phospholipid biosynthesis have been worked out. During the last few years, literature has accumulated on lipid metabolic enzymes of other fungi, as investigators became increasingly interested in this area of research. The present review, after an introduction, will be divided into different sections and each section will deal, comparatively, with various aspects of fungal lipid metabolism and physiology. This review will, therefore, bring out the differences or similarities of lipid metabolism in diverse fungal species.
37 citations