Thermal Degradation and Fire Properties of Fungal Mycelium and Mycelium - Biomass Composite Materials.

Mycelium and mycelium-biomass composites are emerging as new sustainable materials with useful flame-retardant potentials. Here we report a detailed characterisation of the thermal degradation and fire properties of fungal mycelium and mycelium-biomass composites. Measurements and analyses are carried out on key parameters such as decomposition temperatures, residual char, and gases evolved during pyrolysis. Pyrolysis flow combustion calorimetry (PCFC) evaluations reveal that the corresponding combustion propensity of mycelium is significantly lower compared to poly(methyl methacrylate) (PMMA) and polylactic acid (PLA), indicating that they are noticeably less prone to ignition and flaming combustion, and therefore safer to use. The hyphal diameters of mycelium decrease following pyrolysis. Cone calorimetry testing results show that the presence of mycelium has a positive influence on the fire reaction properties of wheat grains. This improvement is attributable to the relatively higher charring tendency of mycelium compared to wheat grain, which reduces the heat release rate (HRR) by acting as a thermal insulator and by limiting the supply of combustible gases to the flame front. The mycelium growth time has been found to yield no significant improvements in the fire properties of mycelium-wheat grain composites.

The evaluation of local oxidative/nitrosative stress in patients with pityriasis versicolor: a preliminary study.

Yeast of Malassezia, members of the microbiologic flora of the skin, cause pityriasis versicolor and have also been implicated in the pathogenesis of other superficial dermatoses. The mechanisms by which the yeast cause these dermatoses, however, are not yet clear, and there have been no studies on the interaction between fungi and keratinocytes, especially the effects of fungi on the production of reactive oxygen/nitrogen species by human keratinocytes. This is the first study we aimed to evaluate the role of oxidative/nitrosative stress in affected skin areas in patients with pityriasis versicolor. Sixty pityriasis versicolor patients and 60 healthy subjects as control group were enrolled. Scraping samples were obtained from the lesional skin areas in patients and from the normal skin areas in controls. The distribution of lesions of pityriasis versicolor was mild in all patients. We have isolated two Malassezia species: M. furfur being isolated in 75% of patients, followed by M. globosa (25%). The levels of oxidative/nitrosative stress biomarkers were significantly higher in patients than the controls (P < 0.001). Our results demonstrated that pityriasis versicolor is associated with significant alteration in oxidant/antioxidant balance. It might be secondary consequence of pityriasis versicolor infection or contributing factor in its pathogenesis.

Expression of antimicrobial peptides and toll-like receptors is increased in tinea and pityriasis versicolor.

In superficial tinea and pityriasis versicolor, the causative fungi are for the most part confined to the stratum corneum which is barely reached by leukocytes. Therefore, a role of non-cellular components in the epidermal antifungal defence was suggested. To investigate the presence of such factors in these infections, the expression of human beta defensins 2 and 3 (hBD-2, hBD-3), RNase 7, psoriasin, toll-like receptors 2, 4 and 9 (TLR2, TLR4 and TLR9) and dectin 2 was analysed by use of immunostainings in skin biopsies. We found that hBD2, hBD3, psoriasin, RNase7, TLR2 and TLR4 were significantly more often expressed in distinct layers of lesional epidermis as compared with uninfected epidermis. In both infections but not in normal skin, hBD2 and hBD3 were commonly expressed within the stratum corneum and in the stratum granulosum. Similarly, psoriasin was seen more often in the upper skin layers of both infections as compared with normal skin. No significant differences between normal and infected skin were found for the expression of TLR9 and dectin 2. Our findings clearly show the expression of specific antimicrobial proteins and defence-related ligands in superficial tinea as well as in pityriasis versicolor, suggesting that these factors contribute to fungal containment.

[Pityriasis versicolor : new aspects of an old disease]. / Pityriasis versicolor : Aktuelles zu einer alten Erkrankung.

Pityriasis versicolor (PV) is one of the most common infectious skin diseases, as well as the most common dermatosis associated with pigmentation alterations of the skin. PV is prevalent in 1% of the population living in temperate climate zones and more common during the summer. In tropical areas, PV is found in up to 50% of all patients consulting a dermatologist. Of the known Malassezia species, M. globosa is currently felt to play a key role in the pathogenesis of PV, as it is most commonly found in PV lesions. In addition, its round-shaped cells may contribute to the characteristic histology of the disease ("spaghetti and meatballs"). However, the clinical appearance of PV including hyper- and hypopigmentation, fluorescence of the lesions, as well as a lack of inflammation despite high fungal load cannot fully be explained by the presence of M. globosa, which is also found on healthy skin. In M. furfur a tryptophan-dependent metabolic pathway generates a number of indole pigments, which may be associated with the clinical appearance of PV. In the model organism Ustilago maydis it was shown that the formation of the indole compounds occurs spontaneously after initial conversion of tryptophan into indole pyruvate controlled by the key enzyme aminotransferase Tam 1. We review the present knowledge of PV and highlight the potential role of Tam1 in explaining the poorly understood aspects of the disease. Promising therapeutic results using the application of Tam1 inhibitors to treat PV support the enzyme's important role in the disease pathogenesis.

Expression of GSTM4 and GSTT1 in patients with Tinea versicolor, Tinea inguinalis and Tinea pedis infections: a preliminary study.

BACKGROUND: Several skin diseases are believed to be associated with oxidative stress. Defence against reactive oxygen species in the skin involves a variety of antioxidant enzymes, including glutathione-S-transferases (GSTs) catalysing the reaction between reduced glutathione, and a variety of exogenously and endogenously derived electrophilic compounds. The mammalian soluble GSTs are divided into five main classes: alpha (A), mu (M), pi (P), theta (T) and zeta (Z). AIM: To investigate the expression of GSTM4 and GSTT1 in lesional and nonlesional skin of patients with dermatophytoses and Tinea versicolor infection. Methods. Expression of GSTM4 and GSTT1 was assessed by immunohistochemistry for dermatophytoses in 15 patients with T. versicolor, 15 patients with Tinea pedis and 8 patients with Tinea inguinalis, and compared with healthy controls (n = 9). After written consent was signed by each participant, punch biopsies were excised from the centre of the lesional skin sites in patients and from the normal skin sites in controls. The relationships between expression of GSTM4 and GSTT1 isoenzymes and fungal infections were also examined. RESULTS: When the normal and infected tissue of these cases were compared according to their staining intensity, GSTM4 expression was found to be stronger in control epithelium than in the epithelium of patients with T. pedis, T. inguinalis or T. versicolor (P < 0.05). By contrast, expression of GSTT1 was stronger in the epithelium of patients infected with any of the three dermatophytes than in control epithelium (P < 0.05). CONCLUSIONS: There is a significant relationship between presence of T. versicolor, T. inguinalis and T. pedis and expression of GSTM4 and GSTT1.

[Cytokine production and dermatophytosis].

The characteristic pathological feature of dermatomycosis is numerous neutrophilic infiltrates within the epidermis. However, the precise mechanism of this infiltration remains unknown. In this study, interleukins 1 beta, 6, and 8, monocyte chemotactic protein-1 (MCP-1), and tumor necrosis factor (TNF)-alpha levels in the medium where keratinocytes were co-cultured with Candida albicans, Malassezia and Trichophyton mentagrophytes, were determined by enzyme-linked immunosorbent assays (ELISAs) in order to estimate the effect of these fungi on the cytokine production from human keratinocytes. The IL-8 level in the supernatants increased with 1 to 14 hours of co-culture in response to live C. albicans, but the other cytokines were undetectable. Furthermore, the mRNA of IL- 8 in keratinocytes was also confirmed to increased. This data suggested that C. albicans directly induce interleukin 8 production from human keratinocytes without activated macrophages. The IL-6, IL-8, and TNF-alpha levels in the culture supernatants increased with 1 to 24 hours of co-culture with keratinocytes and Malassezia species but the MCP-1 level was undetectable. The IL-8 and TNF-alpha levels in the culture supernatants increased with 1 to 24 hours of co-culture with keratinocytes and Trichophyton mentagrophytes but the other cytokine levels were undetectable. The ELISA analysis of cytokine production by human keratinocytes will provide useful information in understanding the pathogenesis of dermatomycosis.

Analyses of skin surface lipid in patients with microbially associated skin disease.

The composition of the total skin surface lipid, free fatty acids and fatty acid of triglyceride was used in discriminant analyses to classify patients with severe acne vulgaris (AV), pityriasis versicolor (PV), seborrhoeic dermatitis (SD) and atopic dermatitis (AD). It was not possible to discriminate between the PV and SD patients but all the lipid groups gave a satisfactory separation between AV, PV + SD and AD patients. A similar separation was obtained when the sex of the patient was studied but not when both sex and disease were taken into account. The results suggest that there are fundamental differences in the composition of skin lipid between patients with microbially associated diseases, but the precise role of the organisms has not been ascertained.

Lipoxygenase activity of Pityrosporum in vitro and in vivo.

Lipid peroxidation has been investigated both in cultures of Pityrosporum supplemented with different lipid classes and in skin surface lipids from patients affected with pityriasis versicolor. Thin-layer chromatography (TLC) and 2 spectrophotometric methods were used: the indirect thiobarbituric acid test and the direct N,N-diethyl-1,4-phenylene-diammonium sulfate (DEPD) test. The coupling of the DEPD test with the TLC technique performed by different eluent systems allowed the detection of the specific lipoperoxides deriving from the oxidation of the different lipid classes. In the cultures, Pityrosporum was capable of peroxidating not only unsaturated free fatty acids, but also unsaturated triglycerides, cholesterol, and squalene. A similar lipid peroxidation was observed in patients with pityriasis versicolor in skin lipids from areas positive for fungal hyphae and spores and fluorescent under the UV lamp (366 nm). The lipoperoxide values were significantly higher (p less than 0.05) than in skin lipids from normal controls. Hyphae and spore-negative areas of patients with pityriasis versicolor, whether apparently normal or achromic, showed no evidence of a significant lipid peroxidation and neither did skin areas of patients with pityriasis alba. Though further investigations are necessary, it seems reasonable to suggest, in analogy with other biologic systems, that the presence in skin lipids of a significant amount of highly reactive and cytotoxic lipoperoxides may play a role in the pathogenesis of skin alterations in pityriasis versicolor, including damage to melanocytes and resulting achromia.

Selenium sulfide in tinea versicolor: blood and urine levels.

The safety of topical selenium sulfide lotion in man has been demonstrated previously. Twenty male patients with a diagnosis of tinea versicolor were randomly assigned to two parallel groups who applied selenium sulfide lotion or the vehicle to the entire skin surface, excluding mucous membranes, for 10 minutes once daily for 7 consecutive days. Blood and urine selenium levels were determined before and after treatment and showed no significant differences between the active drug and vehicle groups on any study day. It would appear that no significant absorption of selenium took place as a result of this treatment regimen.

[Seminal fluid concentration of ketoconazole and its effect on spermatozoa motility]. / Die Seminalplasmakonzentration von Ketoconazol und deren Einfluss auf die Spermatozoenmotilität.

The concentration of Ketoconazole in seminal fluid has been measured in 7 men. The average concentration of 150 ng/g in seminal fluid is much lower than in blood plasma, but for the treatment of candidiasis the concentration in seminal fluid may be too low. A 50-fold higher Ketoconazole-concentration did not disturb sperm motility in 24 men. Therefore there may be no danger for motility of sperms in genital tract of women, for the tested Ketoconazole-concentration was 3-fold higher than the blood serum concentration.

A reappraisal of the role of Pityrosporum orbiculare in pityriasis versicolor and the significance of extracellular lipase.

Pityrosporum orbiculare is an obligate lipophilic yeast in vitro, which suggests it possesses an extracellular lipase crucial for nutrition. If present in vivo, the enzyme would enable the yeast to utilize skin surface lipids, which may therfore play an important role in the pathogenesis of pityriasis versicolor. Cultured P. orbiculare and biopsy material from patients with pityriasis versicolor were investigated for the presence of lipase by electron microscope histochemistry. At sites of lipase activity, fatty acid hydrolyzed from Tween 80 substrate reacts with Ca++ ions to form an insoluble Ca++ soap. Exchange of Ca++ with Pb++ enables the sites of lipase activity to be visualized as electron dense deposits of insoluble lead soap. Surface lipase activity was apparent when the technique was applied to P. orbiculare grown on lipid containing medium and its specificity confirmed by removal of substrate and inhibition by di-isopropyl fluorophosphate and quinine hydrochloride, but not by sodium fluoride. When the same technique was applied to stratum corneum infected with Pityrosporum furfur (Malassez), no reaction product could be detected. It is postulated that lipase, although critical for fungal nutrition in vitro, is unlikely to be of importance in vivo. Skin surface lipids are therefore probably not relevant to the pathogenesis of pityriasis versicolor.