Authors:L. Galgóczy, Gyöngyi Lukács, Ildikó Nyilasi, T. Papp, and Cs. Vágvölgyi
antifungal activity of different statins and the combinations of the two most effective ones (fluvastatin and rosuvastatin) with amphotericin B were investigated in this study on 6 fungal isolates representing 4 clinically important genera, namely
Absidia, Rhizomucor, Rhizopus
. The antifungal effects of statins revealed substantial differences. The synthetic statins proved to be more effective than the fungal metabolites. All investigated strains proved to be sensitive to fluvastatin. Fluvastatin and rosuvastatin acted synergistically and additively with amphotericin B in inhibiting the fungal growth in clinically available concentration ranges. Results suggest that statins combined with amphotericin B have a therapeutic potential against fungal infections caused by Zygomycetes species.
Authors:L. Galgóczy, Liliána Tóth, M. Virágh, T. Papp, and Cs. Vágvölgyi
The mortality rates of fungal infections that affect the central nervous system are high in consequence of the absence of effective antifungal drugs with good penetration across the blood-brain barrier and the blood-cerebrospinal fluid barrier. In the present work in vitro antifungal activities of three good penetrating non-antifungal drugs (amantadine hydrochloride, R-(-)-deprenyl hydrochloride, valproic acid sodium salt) and their combinations with three antifungal agents (amphotericin B, itraconazole, terbinafine) were tested with broth microdilution method against eight fungal isolates belonging to Zygomycetes (Lichtheimia corymbifera, Rhizomucor miehei, Rhizopus microsporus var. rhizopodiformis, Saksenaeavasiformis) and Aspergillus genus (A. flavus, A. fumigatus, A. nidulans, A. terreus). These are known to be possible agents of central nervous fungal infections (CNFI). When used alone, the investigated nonantifungal drugs exerted slight antifungal effects. In their combinations with antifungal agents they acted antagonistically, additively and synergistically against zygomyceteous isolates. Primarily antagonistic interactions were revealed between the investigated drugs in case of Aspergilli, but additive and synergistic interactions were also observed. The additive and synergistic combinations allowed the usage of reduced concentrations of antifungal agents to inhibit the fungal growth in our study. These combinations would be a basis of an effective, less toxic therapy for treatment of CNFI.
Authors:T. Papp, Klára Ács, Ildikó Nyilasi, Erzsébet Nagy, and Cs. Vágvölgyi
The complete ITS (internal transcribed spacer) region coding the ITS1, the ITS2 and the 5.8S rDNA was amplified by polymerase chain reaction from two strains of Gilbertella persicaria, six strains in the Mucoraceae (Mucor piriformis, M. rouxii, M. circinelloides, Rhizomucor miehei, R. pusillus and R. tauricus) and four strains representing three species of the Choanephoraceae (Blakeslea trispora, Choanephora infundibulifera and Poitrasia circinans). Sequences of the amplified DNA fragments were determined and analysed. G. persicaria belongs to the monogeneric family (Gilbertellaceae), however, originally it was described as Choanephora persicaria. The goal of this study was to reveal the phylogenetic relationship among fungi belonging to Gilbertellaceae, Choanephoraceae and Mucoraceae. Our results support that the “intermediate” position of this family is between Choanephoraceae and Mucoraceae.
Authors:Zs. Palágyi, B. Linka, T. Papp, and Cs. Vágvölgyi
Cells of the astaxanthin-producing yeast
were subjected to successive
Co and UV irradiation. Colonies exhibiting increased pigmentation were recovered from different non-selective plates. Mutant strains were subcultured to ensure their genetic homogeneity and their pigment production was characterized. Analysis of the metabolic patterns of 7 pigment-overproducing mutants (derived from 3 wild-type parental isolates) revealed different patterns of carotenoid production: the greatest increase in astaxanthin production (6.7-fold) was found for
strain ATCC 24229/S119 (274 μ g g
dry weight). Mutant strains with increased total carotenoid content, but without significant change in astaxanthin production, were also isolated.
Authors:Z. Farkas, J. Márki-Zay, Judit Kucsera, Cs. Vágvölgyi, W. Golubev, and Ilona Pfeiffer
Wickerhamomyces anomalus VKM Y-159 strain produces two types of toxin designated as WAKT a and WAKT b, encoded by chromosomal genes. The WAKT a toxin is heat-labile, pronase sensitive acting in pH range 3–4 affecting on several yeasts including pathogenic Candida species while the WAKT b toxin is protease- and thermo-resistant, acting in pH range 3–7 on two species, Candida alai and Candida norvegica. The rapid decrease of the number of viable cells after toxin treatment demonstrates that both toxins have cytocidic effect.
Authors:L. Kredics, Kata Terecskei, Zsuzsanna Antal, A. Szekeres, L. Hatvani, L. Manczinger, and Cs. Vágvölgyi
isolates were screened for the production of proteolytic activities at 10 °C. Based on the activity profiles determined with paranitroanilide substrates at 5 °C, strain T221 identified as
was selected for further investigations. The culture broth of the strain grown at 10 °C in casein-containing culture medium was concentrated by lyophilization and subjected to gel filtration, which was followed by chromatofocusing of the fraction showing the highest activity on
-benzoyl-Phe-Val-Arg-paranitroanilide. The purified enzyme had a molecular weight of 24 kDa, an isoelectric point of 7.3 and a pH optimum of 6.2. The temperature optimum of 25 °C and the low thermal stability suggested that it is a true cold-adapted enzyme. Substrate specificity data indicate that the enzyme is a proteinase with a preference for Arg or Lys at the P1 position. The effect of proteinase inhibitors suggests that the enzyme has a binding pocket similar to the one present in trypsin.
Authors:E. Horváth, G. Papp, Z. Gazdag, J. Belágyi, Á. Blaskó, J. Deli, Cs. Vágvölgyi, and M. Pesti
A carotenoid-less Phaffia rhodozyma mutant (MCP 325) exhibited significantly higher resistance to oxidative stressors such as menadione, H2O2 and K2Cr2O7 than its astaxanthin-producing parental strain (MCP 324). The absence of carotenoids in the mutant did not explain this phenomenon. The cause of the decreased superoxide, hydroxyl radical and glutathione contents, the increased peroxide concentration and the elevated specific activity of catalase under uninduced conditions may be a second mutation. Peroxide treatment induced specific catalase activity in the mutant but not in the parental strain. Regulation of these processes led to the result that, in spite of the mutations, the two strains exhibited the same multiplication rate and generation time.
Authors:M. Takó, Elvira Farkas, Szabina Lung, Judit Krisch, Cs. Vágvölgyi, and T. Papp
Extracellular β-glucosidase activity of 94 strains, representing 24 species of the genera
Gilbertella, Mucor, Rhizomucor
was evaluated in submerged culture and under solid state fermentation on wheat bran.
G1 isolate showed the highest activity (70.9 U ml
) followed by other
(58.6–59.0 U ml
isolates (29.2–42.0 U ml
). Optimum temperature for enzyme production was 25 °C for
, and 30 °C for
strains. Enzymes of
strains proved to be thermotolerant preserving up to 92.8% residual activity after heating to 75 °C in the presence of cellobiose substrate. Enzymes of
chibinensis, R. miehei
strains were activated at acidic condition (pH 4). Glucose was a strong inhibitor for each fungal β-glucosidase tested but some of them showed ethanol tolerance up to 20% (v/v). Ethanol also activated the enzyme in these strains suggesting glycosyl transferase activity.