Heterokaryosis in Microsporum gypseum

The basic properties of heterokaryosis have been studied with the use of morphological and biochemical mutants ofMicrosporum gypseum. A direct proof of heterokaryosis was given with the help of the isolation of hyphal tips. Heterokaryons formed from aconidial components conidiate abundantly. The heterokaryotic constitution is preserved only with the transfer of mycelium; by microconidia the transfer is not effected.     

Diploids in Microsporum gypseum

The paper studies diploids in dermatophyteMicrosporum gypseum. They were isolated as the more rapidly growing sectors from heterokaryons on minimal medium. They are characterized by their wild morphology, conidiation and growth rate, and they are prototrophic. In their genome they contain all the markers present in both mutant components.     

Enzymatic activities of Microsporum canis and Microsporum gypseum strains.

The presence of 11 enzymatic activities, detected by qualitative methods, and 19 enzymes, semi-quantitatively detected by API ZYM system, in strains belonging to Microsporum canis and Microsporum gypseum has been studied. No pronounced differences were noted between Microsporum canis and Microsporum gypseum, although Microsporum gypseum presented in some cases more intense enzymatic activities than Microsporum canis.     

Macroconidial Germination in Microsporum gypseum

Biochemical events which occur during macroconidial germination have been studied in the dermatophyte Microsporum gypseum. The specific activity levels of various metabolic enzymes have been assayed during germination time periods. The accumulated levels of several of these enzymes, as a function of exogenous carbohydrate source, have been investigated. M. gypseum was found to possess a constitutive glyoxalate shunt, a constitutive glucokinase, a fructose phosphoenolpyruvate transferase, and a mannitol phosphoenolpyruvate transferase. The integration of endogenous reserve utilization during germination is discussed. The purification and properties of an alkaline phosphatase and its possible relationship to sporulation and spore germination also are described.     

Influence of supplementation of saturated alkanes on the membrane properties of Microsporum gypseum

Microsporum gypseum cells grown on saturated alkanes of different chain lengths (C10, C12, C14, C16 and C18) exhibited increased levels of total phospholipids and sterols. A significant increase in the content of phosphatidylcholine was observed in alkane-grown cells. Increased saturation of phospholipid fatty acid was observed with all the alkanes studied, which was mainly due to the decreased amount of C18:1 and C18:2 with concomitant increase in the levels of palmitic acid. The affinity for glycine changed in alkane-supplemented cells as compared to glucose-grown cells. 1-Anilino-naphthalene-8-sulphonate (ANS) binding to the spheroplast membrane demonstrated increased binding sites in supplemented cells. These results are discussed in terms of the effect of altered lipid composition on the membrane structure and function of this fungus.     

Heat-induced Macroconidia Germination in Microsporum gypseum

A method for obtaining purified ungerminated macroconidia is described, and a technique for obtaining 85 to 90% germination of macroconidia under normal nutritional conditions is presented.     

Canine onychomycosis produced by Microsporum gypseum. A case report

One case of severe canine onychomycosis is described. The aetiological agent was identified as Microsporum gypseum. The incidence of this fungus in this kind of pathology is discussed, with special attention to the successful treatment with topic enilconazole and systemic griseofulvin.     

Regulation and Self-Inhibition of Microsporum gypseum Macroconidia Germination

Germination of Microsporum gypseum macroconidia was accompanied by the release of alkaline protease, calcium ions, and inorganic phosphate into the germination fluid. The rate of germination was greatest during the first 2 hr, decreasing thereafter. This decrease in rate was accompanied by a decrease in protease activity, which was caused by an interaction of the enzyme with the inorganic phosphate released from the spores and accumulated in the germination medium after 2 hr. Germination of high spore densities was regulated by the ratio of released phosphate to protease protein, resulting in a constant percentage of germination at both high and low spore densities. A germination-defective mutant strain failed to germinate normally and released excessively high concentrations of phosphate into the germination medium during the initial 2 hr of incubation. Addition of calcium ions to germination mutant macroconidia stabilized spore morphology, prevented protease inactivation, and allowed normal germ-tube outgrowth. The germination of macroconidia appears to be regulated by the release of phosphate ions, which then inhibit the alkaline protease.     

Correlation between intracellular cAMP levels and phospholipids of Microsporum gypseum.

Atropine, a modulator of cAMP has been used to examine the relationship between phospholipids and intracellular levels of cAMP in Microsporum gypseum. A decreased phospholipid content was observed in atropine grown cells as a result of reduced levels of intracellular cAMP. This decline was caused by the inhibitory effect of atropine on adenylate cyclase. Lowered phospholipid content was supported by decreased [14C]acetate incorporation as well as reduced activities of key enzymes of phospholipid biosynthesis. In vitro supplementation of atropine in control cells also caused inhibition in lipid synthesis indicating similar effects of atropine and its metabolites. These results in conjunction with our previous report, in which enhanced levels of cAMP resulted in increased phospholipid synthesis, suggest a direct correlation between phospholipid biosynthesis and intracellular levels of cAMP in M. gypseum.     

Effect of dibutyryl cyclic AMP on lipid synthesis in Microsporum gypseum

The influence of intracellular levels of cAMP on the lipid synthesis of Microsporum gypseum has been examined by exogenous supplementation of dibutyryl cAMP and its activators/inhibitors. Incorporation of [14C]acetate into various lipid fractions of M. gypseum was markedly enhanced in the presence of dibutyryl cAMP and its modulators, probably as a consequence of increased intracellular cAMP levels, which, in turn, affected the lipid biosynthesis. Increased activities of phosphatidic acid phosphatase, glycerol kinase, ethanolamine kinase and choline kinase in the presence of these additives supports the enhanced synthesis of phospholipids and suggests that lipid biosynthesis is being controlled by cAMP in M. gypseum.     

Antifungal activity of Lactobacillus against Microsporum canis, Microsporum gypseum and Epidermophyton floccosum

A total of 220 lactic acid bacteria isolates were screened for antifungal activity using Aspergillus fumigatus and Aspergillus niger as the target strains. Four Lactobacillus strains exhibited strong inhibitory activity on agar surfaces. All four were also identified as having strong inhibitory activity against the human pathogenic fungi Microsporum canis, Microsporum gypseum and Epidermophyton floccosum. One of the four lactobacilli, namely Lb. reuteri ee1p exhibited the most inhibition against dermatophytes. Cell-free culture supernatants of Lb. reuteri ee1p and of the non-antifungal Lb. reuteri M13 were freeze-dried and used to access and compare antifungal activity in agar plate assays and microtiter plate assays. Addition of the Lb. reuteri ee1p freeze-dried cell-free supernatant powder into the agar medium at concentrations greater than 2% inhibited all fungal colony growth. Addition of the powder at 5% to liquid cultures caused complete inhibition of fungal growth on the basis of turbidity. Freeze-dried supernatant of the non-antifungal Lb. reuteri M13 at the same concentrations had a much lesser effect. As Lb. reuteri M13 is very similar to the antifungal strain ee1p in terms of growth rate and final pH in liquid culture, and as it has little antifungal activity, it is clear that other antifungal compounds must be specifically produced (or produced at higher levels) by the anti-dermatophyte strain Lb. reuteri ee1p. Reuterin was undetectable in all four antifungal strains. The cell free supernatant of Lb. reuteri ee1p was analyzed by LC-FTMS using an Accela LC coupled to an LTQ Orbitrap XL mass spectrometer. The high mass accuracy spectrum produced by compounds in the Lb. reuteri ee1p strain was compared with both a multianalyte chromatogram and individual spectra of standard anti-fungal compounds, which are known to be produced by lactic acid bacteria. Ten antifungal metabolites were detected.     

The nuclear DNA-dependent ribonucleic acid polymerases of the dermatophytic fungus Microsporum gypseum.

The DNA-dependent RNA polymerases of the dermatophytic fungus Microsporum gypseum were partially characterized. Nuclear extracts prepared from vegetative mycelia were fractionated by DEAE-Sephadex chromatography into three enzyme species which resembled in most of their characteristics those of other eukaryotic organisms.     

Relationship of nuclear segregation and macroconidial germination in Microsporum gypseum

Microsporum gypseum macroconidia germinated at 37 C possessed from one to eight nuclei per germinated spore compartment. The distribution of nuclei per spore compartment was the result of a random packaging of nuclei from the available nuclear population. Partial inhibition of germination by incubation at 25 C or at 37 C in the presence of 10(-4)m phenyl methyl sulfonyl-fluoride resulted in an enrichment of germinated spores containing high numbers of nuclei per compartment. The selection for higher nuclear numbers was statistically significant. Compartments possessing high numbers of nuclei appeared to be precommitted to spore germination since they were not sensitive to germination inhibition. The effect of incubation temperature variation on spore germination is discussed with respect to the organism's natural environment.     

石膏样小孢子菌致婴儿额部体癣1例

报道1例由石膏样小孢子菌引起的婴儿额部体癣。患者男性,出生半月,左额部红斑丘疹水疱7 d。经真菌学检查确诊为石膏样小孢子菌导致的体癣。给予硝酸舍他康唑软膏外用,1周后皮损完全愈合。