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Cells of the astaxanthin-producing yeast Xanthophyllomyces dendrorhous were subjected to successive 60 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 X. dendrorhous strain ATCC 24229/S119 (274 μ g g −1 dry weight). Mutant strains with increased total carotenoid content, but without significant change in astaxanthin production, were also isolated.

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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.

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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, Saksenaea vasiformis) 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.

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The in vitro 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 and Syncephalastrum . 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.

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Earlier neurochemical studies suggested that human brain carboxypeptidase B may play a significant role in the degradation of amyloid-β1-42 in the brain. Using an immunohistochemical technique we report here on the neuronal expression and distribution of this enzyme in the segments (CA1a, CA1b and CA1c) of the CA1 subfield and in area CA4 of the hippocampus in normal and Alzheimer's disease brain samples. Its distribution was compared with the appearance of neurofibrillary tangles in the same brain sample. For immunohistochemical localization of carboxypeptidase B, a specific C14-module antibody was applied, together with the Gallyas silver impregnation technique for the demonstration of neurofibrillary tangles. The results revealed that, in the control samples, most of the immunoreactivity appeared in segment CA1a in the pyramidal cells, less in segment CA1b and least in segment CA1c. In the Alzheimer's disease samples, there was no particular immunostaining in the neurons, but, a large number of silver-impregnated degenerated neurons appeared. The results support the suggestion that carboxypeptidase B may play a significant role in elimination of the intracellular accumulation and toxicity of amyloid-β in the human brain and thereby protect the neurons from degeneration.

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Acta Biologica Hungarica
Authors:
L. G. Puskás
,
L. Tiszlavicz
,
Zs. Rázga
,
L. L. Torday
,
T. Krenács
, and
J. Gy. Papp

Recent and historical evidence is consistent with the view that atherosclerosis is an infectious disease or microbial toxicosis impacted by genetics and behavior. Because small bacterial-like particles, also known as nanobacteria have been detected in kidney stones, kidney and liver cyst fluids, and can form a calcium apatite coat we posited that this agent is present in calcified human atherosclerotic plaques. Carotid and aortic atherosclerotic plaques and blood samples collected at autopsy were examined for nanobacteria-like structures by light microscopy (hematoxylin-eosin and a calcium-specific von Kossa staining), immuno-gold labeling for transmission electron microscopy (TEM) for specific nanobacterial antigens, and propagation from homogenized, filtered specimens in culture medium. Nanobacterial antigens were identified in situ by immuno-TEM in 9 of 14 plaque specimens, but none of the normal carotid or aortic tissue (5 specimens). Nanobacteria-like particles were propagated from 26 of 42 sclerotic aorta and carotid samples and were confirmed by dot immunoblot, light microscopy and TEM. [3H]L-aspartic acid was incorporated into high molecular weight compounds of demineralized particles. PCR amplification of 16S rDNA sequences from the particles was unsuccessful by traditional protocols. Identification of nanobacteria-like particles at the lesion supports, but does not by itself prove the hypothesis that these agents contribute to the pathogenesis of atherosclerosis, especially vascular calcifications.

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Extracellular β-glucosidase activity of 94 strains, representing 24 species of the genera Gilbertella, Mucor, Rhizomucor , and Rhizopus was evaluated in submerged culture and under solid state fermentation on wheat bran. Gilbertella persicaria G1 isolate showed the highest activity (70.9 U ml −1 ) followed by other Gilbertella (58.6–59.0 U ml −1 ) and Rhizomucor miehei isolates (29.2–42.0 U ml −1 ). Optimum temperature for enzyme production was 25 °C for Gilbertella and Mucor , and 30 °C for Rhizomucor and Rhizopus strains. Enzymes of R. miehei 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 Mucor racemosus f. chibinensis, R. miehei and Rhizopus microsporus var. oligosporus 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.

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Acta Botanica Hungarica
Authors:
P. Török
,
T. Miglécz
,
O. Valkó
,
K. Tóth
,
A. Kelemen
,
Á.-J. Albert
,
G. Matus
,
A. Molnár V
,
E. Ruprecht
,
L. Papp
,
B. Deák
,
O. Horváth
,
A. Takács
,
B. Hüse
, and
B. Tóthmérész

In the present paper we report original thousand-seed weight data for the flora of the Pannonian Basin. Our goal was to demonstrate the usefulness of seed weight databases by analysing seed weight data in relation to social behaviour types and life forms. We specifically asked the following questions: (i) how the seed weights are related to social behaviour type categories; (ii) how the life form of the species influences seed weight differences between respective social behaviour types? Own weight measurements are provided for 1,405 taxa; and for 187 taxa we published seed weight data for the first time: these were mostly endemics, orchids and/or species with Pontic, Caspian or continental distribution. Several taxonomic or functional groups are underrepresented in our database, like aquatic plants, rare arable weeds and sub-Mediterranean species. Problematic taxa, some difficult-to-harvest species or species with low seed production and cultivated adventives are also underrepresented. We found that the plant strategies expressed by social behaviour types were significantly different in terms of seed weights. The lowest seed weight scores were found for natural pioneers, whereas the highest ones were found for adventives and introduced cultivated plants. Short-lived herbaceous species had significantly higher seed weight scores than herbaceous perennials. No significant differences were found between specialists and generalists within the stress tolerant group. We found that short-lived graminoids possess heavier seeds than perennial graminoids, perennial and annual forbs. Naturalness scores were negatively correlated with seed weights. Our findings showed that seed collections and databases are not only for storing plant material and seed weight data, but can be effectively used for understanding ecological trends and testing plant trait-based hypotheses. Even the identified gaps underline the necessity of further seed collection and measurements.

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