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Biomedical subjects

E K Novák

Publications and source records attributed to E K Novák.

At least 19 recordsLinked to original sources
PubMed1999

Hygienic mycology in Hungary.

In Hungary the medical mycological research concerning the systemic (so-called deep) mycoses started in the National Institute of Hygiene. The Mycology Department has been founded in 1955 in this Institute with nation-wide authority as a routine diagnostic laboratory for clinical specimens from systemic mycotic infections. Three years later its activity was broadened--on ground of the experiences--to cover the total field of hygiene, thus we had to establish the "mycologia hygienica" (hygienic mycology), however, this has not been accepted as an independent discipline. Here a short, selected overview is given of our experiences. In the following the trends of the activity is demonstrated along the subdivisions of hygiene (epidemiology, environmental-hygiene, professional and occupational-, nutritional and food hygiene). In respect of hygiene, however, the fungi play a Janus-faced (more exactly Dr. Jekyll-Mr. Hyde) role, as they can behave not only harmful but also beneficial.

Animals↗
PubMed1982

Some characteristics of nystatin-resistant sterol mutants of Candida albicans.

Various stable, auxotrophic and nystatin-resistant sterol mutants of Candida albicans were isolated after nitrosoguanidine treatment. Sterol mutants were divided into groups on the basis of the ultraviolet spectra and thin-layer chromatographic patterns of their nonsaponifiable sterol extracts. They were further characterized by their conductometrically measured nystatin-induced ion release. These sterol mutants displayed a decreased growth yield and an increased cell volume. On media containing 0.01% of the carbon sources, most of them could assimilate glycerol, alpha-methyl-D-glucoside, DL-lactic acid, L-sorbose, L-arabinose and ribitol only to a significantly reduced extent, or not at all. It is presumed that these properties result from the altered sterol composition of the plasma membrane.

Candida albicans↗
PubMed1981

Freeze fracture electron microscopical investigation of Candida albicans cells sensitive and resistant to nystatin.

A sterol mutant was isolated after nitrosoguanidine treatment, on the basis of th nystatin-resistant phenotypic behaviour, from a Candida albicans strain requiring adenine. The plasma membrane ultrastructure of the resistant mutant, observed by freeze-fracture electron microscopy, was not significantly different from the parental, ergosterol producing nystatin-sensitive strain. Nystatin treatment caused no ultrastructural change in the resistant strain, but led to the aggregation of membrane particles in the sensitive strain: this effect was considered to be the specific effect of nystatin. Other, probably nonspecific effects of nystatin on the sensitive strain were a deepening and deformation of invaginations, atypical membrane fracture, certain changes in the structure of cell wall and special ornamentation of its surface. No change in the intracellular membranes was observed.

Candida albicans↗
PubMed1981

Morphogenetic effect of L-cysteine on dermatophytes.

In the presence of L-cysteine, all the 24 dermatophyton fungi under study grew poorly. None of the strains, except Trichophyton menatographytes var. quinckeanum, grew in the presence of 0.04 M L-cysteine. The strains growing on a medium containing L-cysteine showed morphological changes. The surface of the colonies lost its velvety appearance and became awnless or waxy. The strains grown in the presence of L-cysteine abundantly formed chlamydospores. The chains of chlamydospores may resemble yeast cell chains, but true budding forms were not found in cultures in vitro. If strains precultivated on L-cysteine-containing medium were injected intraperitoneally into mice budding forms appeared in the peritoneal fluid.

Arthrodermataceae↗
PubMed1976

The macroconidial septum of some dermatophyton species.

The septum of the macroconidium (MC) of dermatophytes was examined by light microscopy. Significant taxonomical differences between species have not been found. The septa seem to be three-layered, but only the middle layer can be considered a septum in the wall substance of two neighbouring chambers, impressed and completed by the septum. The septum verum originates from the middle layer of the three-layered MC wall or from its surface adjacent to the chamber wall. This type of septum is different from that described in Ascomycetes and other species. Light microscopic findings are insufficient to characterize the nature of the septal pore. The microscopic observation of the layers of the MC wall and of the septum may be disturbed by misleading optical phenomena.

Arthrodermataceae↗