Acta Biologica Hungarica

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Double-Stranded RNA Elements and Virus-Like Particles in Aspergilli

J. Varga, Beáta Tóth, Szilvia Szencz, J. Molnár, more

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 355-363

Mycoviruses with double-stranded RNA (dsRNA) genomes are frequently encountered in Aspergillus isolates. A detailed study of such dsRNA elements in black Aspergillus isolates collected worldwide was carried out, and the data were analysed. The results indicate that about 10% of black Aspergilli are infected. However, the geographic distribution of infected isolates exhibits large variations; 3–13%...

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Characterization of the Extracellular Enzyme Systems of Trichoderma viride AH124

L. Manczinger, Zsuzsanna Antal, Anneke Schoop, L. Kredics

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 223-229

A mycoparasitic Trichoderma viride strain was investigated for the production of extracellular enzymes important in antagonism, by using natural and chromogenic substrates. Some of these enzymes, such as β-1,3-glucanases, and low levels of proteases were produced constitutively. Under inductive conditions, the measurable activities of β-1,3-glucanase, protease and aspecific chitinase increased, while...

article

Interaction Between Mitochondria Derived From Incompatible Black Aspergillus Isolates

F. Kevei, Á. Juhász, Zsuzsanna Hamari

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 201-210

As black Aspergillus isolates are highly heterokaryon-incompatible mitochondrial transmissions were performed by protoplast fusion. Donor strains with oligomycin-resistant mitochondria and sensitive recipient partners of various A. japonicus isolates were applied and the progeny were selected for oligomycin resistance and for recipient nuclear phenotype. These strains basically inherited the mitochondrial...

article

Editorial

János Salánki

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 187-187

article

Cytoskeleton in Regenerating Protoplasts and Restoration of Cell Polarity in the Yeast Saccharomyces cerevisiae

A. Svoboda, Iva Slaninová, Alena Holubářová

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 325-333

The actin cables and microtubules were disrupted during protoplasting in Saccharomyces cerevisiae cells. In the process of protoplast regeneration, the cytoplasmic microtubules were the first to be restored; the actin patches remained regularly distributed under the surface of the growing protoplast. After the cell wall had been regenerated in a gelatine medium, the actin patches aggregated into clusters,...

article

Evaluation of Genetic Diversity of Poplar Genotypes by RAPD and AP-PCR Analysis

O. Törjék, Erzsébet Kiss, J. Kiss, M. Kondrák, more

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 345-354

RAPD (randomly amplified polymorphic DNA) and AP-PCR (arbitrarily primed PCR) were utilized to establish the genetic diversity of 19 Populus genotypes. A set of 40 primers of random sequence was tested, of which 35 exhibited polymorphism. Eighteen primers generated 162 easily detectable bands between 250 and 2500 base pairs in size, sufficient to distinguish between the genotypes. Similarity measures,...

article

Occurrence of Metronidazole and Imipenem Resistance Among Bacteroides fragilis Group Clinical Isolates in Hungary

Elisabeth Nagy, J. Sóki, Edit Urbán, Ildikó Szőke, more

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 271-280

During the period between 1987 and 1997, various surveillances of the antibiotic resistance of B. fragilis group isolates revealed that practically all the isolates tested were susceptible to imipenem, metronida-zole and chloramphenicol; very few isolates (2.5%) exhibited resistance to amoxicillin/clavulanic acid. However, similarly as in some southern European countries, the percentages of the isolates...

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Effects of Double-Stranded RNA Viruses on the Reproduction of Phaffia rhodozyma

Ilona Pfeiffer, Judit Litter, Zs. Pénzes, Judit Kucsera

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 299-306

DsRNA viruses were transferred from a virus-containing strain to a virus-free strain of Phaffia rhodozyma by protoplast fusion. The resulting new strain carried all three types of dsRNA of the virus-containing strain and had the electrophoretic karyotype of the virus-free strain. The effects of the dsRNA viruses on the host fitness were checked by following the asexual and the sexual reproductivity...

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Cell Density-Correlated Induction of Pyruvate Decarboxylase Under Aerobic Conditions in the Yeast Pichia Stipitis

M. Mergler, U. Klinner

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 265-269

During the aerobic batch cultivation of P. stipitis CBS 5776 with glucose, pyruvate decarboxylase was activated in a cell number-correlated manner. Activation started when a cell number between 7×10⁷ and 1×10⁸ cells ml⁻¹ was reached and the enzyme activity increased during further cultivation. This induction might have been triggered either by an unknown quorum sensing system or by a shortage of cytoplasmic...

article

Production and Regeneration of Protoplasts from Gremmeniella abietina and Ascocalyx abietis

Liliane Petrini, O. Petrini

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 307-313

This work was undertaken to develop a system of protoplast isolation and regeneration for G abietina and A. abietis that could be of use for the genetic manipulation of both species. Nuclear staining was performed to assess the nuclear conditions of the protoplasts. Of the 19 enzyme complexes studied, only 10 were found to have some lytic effect on either Gremmeniella, A. abietis, or both. Only snail...

article

Genetic Analysis in the Asexual Fungus Aspergillus niger

K. Swart, A. J. M. Debets, C. J. Bos, Marijke Slakhorst, more

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 335-343

The genetics of A. niger has been developed since 1980. An overview is presented of the advances in developing methods and collecting data. Important tools have been a) the application of essentially different methods to isolate mutants, b) the adaptation to A. niger of A. nidulans methodology for analysis of the parasexual cycle, c) the choice of marker genes, and in some cases the artificial introduction...

article

Xylem Colonization of Tomato by Azorhizobium Caulinodans ORS571

E. C. Cocking

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 189-194

Tomato seedlings growing aseptically in Murashige and Skoog Medium were inoculated with Azorhizobium caulinodans ORS571 (pXLGD4), carrying the lacZ reporter gene. By microscopic analyses of inoculated tomato roots, it has been demonstrated that the xylem of tomato roots can be colonized by Azorhizobium. We discuss whether this colonization of the xylem of tomato roots by diazotrophic azorhizobia might...

article

Ethanol-Induced Cell Aggregation (Flocculation) and its Physiological Background in Schizosaccharomyces pombe Rive 4-2-1

Anna Maráz, Anna Geleta

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 231-239

Cell aggregation (flocculation) of the yeast Schizosaccharomyces pombe strain RIVE 4-2-1 developed in glucose-containing medium, but only in the presence of ethanol. Cell surface proteins which participated in cell to cell interactions were characterised by the susceptibility of flocculation to different proteolytic enzymes, heat treatment, denaturing and thiol compounds and by the inhibition of flocculation...

article

Variability of Isozyme and Rapd Markers Among Isolates of Mucor genevensis

Cs. Vágvölgyi, Zs. Kasza, Ildikó Nyilasi, Klára Ács, more

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 365-373

Mucor genevensis is a dimorphic and homothallic fungal species (Zygomycetes). Ten M. genevensis strains, each strain of the recently described new homothallic species (M. meguroense and M. hachijyoensis) and strains of M. hiemalis and M. piriformis (as outgroups for numerical analysis) were investigated. Five different enzyme systems (CAT, GDH, G6D, MDH and SOD) and five 10-bp random primers were...

article

Post-Antibiotic and Synergic Effects of Fluoroquinolones and Ceftazidime in Combination Against Pseudomonas Strains

I. Mayer, E. Nagy

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 241-248

Infectious complications are still the leading cause of morbidity and mortality in seriously ill patients [1–3]. To combat the resistance of (mainly Gram-negative, non-fermentative) bacteria, e.g. Pseudomonas aeruginosa, to a wide spectrum of antibiotics, drug combination therapy has been widely adopted as standard clinical practice since the late 1990s. β-Lactam combinations are not optimal and the...

article

Variation of Isoenzyme and Rapd Patterns in Candida Albicans Morphological Mutants with Altered Colony Ultrastructure

M. Pesti, Cs. Vágvölgyi, T. Papp, A. Nagy, more

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 289-298

Molecular typing methods were applied to characterize four stable morphological mutants [1] isolated from a UV-induced unstable mutant colony of Candida albicans. The wild-type strain (ATCC 64385), the intermediate unstable mutant and its four morphologically altered derivatives revealed the same elec-trophoretic karyotypes. Of the five isoenzymes tested (catalase, malate dehydrogenase, glutamate...

article

Cell-Wall Composition and Polysaccharide Synthase Activity Changes Following Photoinduction in Trichoderma viride

M. Nemčovič, V. Farkaš

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 281-288

The differentiation and metabolism in the soil-borne saprophytic deuteromycete Trichoderma viride are subject to control by light. We have investigated the effect of illumination of mycelia on the activities of cell-wall synthesizing enzymes β-1,3-glucan synthase and chitin synthase and on the composition of cell walls. After 10 min illumination of dark-grown mycelia with white fluorescent light at...

article

Identification of Yeasts Isolated from Poultry Meat

T. Deák

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 195-200

In an assessment of the potential role of yeasts in the spoilage of poultry meat, the population and species diversity of yeasts were determined on 50 commercial raw and processed chicken and turkey product samples. Initial populations (log₁₀ cfu/g) ranged from less than 0.1 to 2.9, and increased by the expiration date to 0.4 to 5.1, respectively. 145 of 152 isolates were identified as belonging to...

article

Surface Structures of New and Lesser Known Species of Thermobifida as Revealed by Scanning Electron Microscopy

J. Kukolya, L. Szabó, L. Hornok

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 211-221

Surface structures of representatives of the genus Thermobifida were examined by scanning electron microscopy. Spores formed at the tips of multibranched sporophores initially resembled short sausages; then, upon maturation, they gradually built up their typical ovoid shape. Characteristic differences were observed between T. cellulolytica strain TB108 and T. fusca strains TM51. The spores of TB108...

article

Fungal Genotype Controls Mutualism and Sex in Brachypodium sylvaticum Infected by Epichloë sylvatica

G. Meijer, A. Leuchtmann

Acta Biologica Hungarica > 2001 > 52 > 2-3 > 249-263

The fungal endophyte Epichloë sylvatica (Clavicipitaceae, Ascomycota) may obligatorily infect the woodland grass Brachypodium sylvaticum, on which it can display two alternative modes of reproduction. During the sexual cycle, external stromata suppress host flowering and production of seed (choke disease), whereas in the asexual cycle the fungus remains asymptomatic and transmits vertically by seeds...

INFONA - science communication portal

Acta Biologica Hungarica

Double-Stranded RNA Elements and Virus-Like Particles in Aspergilli

Characterization of the Extracellular Enzyme Systems of Trichoderma viride AH124

Interaction Between Mitochondria Derived From Incompatible Black Aspergillus Isolates

Editorial

Cytoskeleton in Regenerating Protoplasts and Restoration of Cell Polarity in the Yeast Saccharomyces cerevisiae

Evaluation of Genetic Diversity of Poplar Genotypes by RAPD and AP-PCR Analysis

Occurrence of Metronidazole and Imipenem Resistance Among Bacteroides fragilis Group Clinical Isolates in Hungary

Effects of Double-Stranded RNA Viruses on the Reproduction of Phaffia rhodozyma

Cell Density-Correlated Induction of Pyruvate Decarboxylase Under Aerobic Conditions in the Yeast Pichia Stipitis

Production and Regeneration of Protoplasts from Gremmeniella abietina and Ascocalyx abietis

Genetic Analysis in the Asexual Fungus Aspergillus niger

Xylem Colonization of Tomato by Azorhizobium Caulinodans ORS571

Ethanol-Induced Cell Aggregation (Flocculation) and its Physiological Background in Schizosaccharomyces pombe Rive 4-2-1

Variability of Isozyme and Rapd Markers Among Isolates of Mucor genevensis

Post-Antibiotic and Synergic Effects of Fluoroquinolones and Ceftazidime in Combination Against Pseudomonas Strains

Variation of Isoenzyme and Rapd Patterns in Candida Albicans Morphological Mutants with Altered Colony Ultrastructure

Cell-Wall Composition and Polysaccharide Synthase Activity Changes Following Photoinduction in Trichoderma viride

Identification of Yeasts Isolated from Poultry Meat

Surface Structures of New and Lesser Known Species of Thermobifida as Revealed by Scanning Electron Microscopy

Fungal Genotype Controls Mutualism and Sex in Brachypodium sylvaticum Infected by Epichloë sylvatica

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