Biomedical subjects

D Hudecová

Publications and source records attributed to D Hudecová.

14 recordsLinked to original sources

PubMed2004

Chloride transport in the vegetative mycelia of filamentous fungus Trichoderma viride.

The influx of chlorides into Trichoderma viride vegetative submerged mycelium was measured by means of the radionuclide (36)Cl(-). It was found that the (36)Cl(-) influx was time-dependent (the steady-state was established with t(1/2 )= 25 min at 25 degrees C), pH-dependent (with pH optimum between 4-5.5), temperature-dependent (at about 15 degrees C), and concentration-dependent (K(M)(Cl(-))) = 47.6 +/- 4.2 micromol x l(-1); J(max) = 11.5 +/- 0.7 pmol(Cl(-)) x min(-1). mg(dry mass) (-1)). The (36)Cl(-) influx was inhibited by Br(-) but not F(-), I(-), SO(4)(2-), HPO(3)(2-) and HCO(3)(-). The presence of vanadate (P-type ATPase inhibitor) moderately stimulated the (36)Cl(-) influx but the presence valinomycin (electrogenic K(+) ionophore), salicylate (known to release Ca(2+) from Trichoderma viride internal stores) were without effect on the (36)Cl(-) influx. The results suggest that the (36)Cl(-) influx is mediated by a carrier and that the transport is electroneutral, probably Cl(-)/OH(-) antiport.

Biological Transport↗

PubMed2004

Kojic acid and its derivatives: history and present state of art.

Kojic acid (5-hydroxy-2-hydroxymethyl-4-pyranone) represents an attractive polyfunctional skeleton for development of biologically active compounds. The authors prepared a great variety of kojic acid derivatives and selected biological properties have been studied. Thus, kojic acid derivatives are promising compounds that might advantageously be used in human and/or veterinary medicine and also in preparation of new, even more biologically active preparations.

Animals↗

PubMed2002

Copper complexes with bioactive ligands. Part II--Antifungal activity.

Antifungal activity of new copper(II) complexes of 2-methylthionicotinate (2-MeSNic) of the composition Cu(2-MeSNic)2(MeNia)(2).4H2O (where MeNia is N-methylnicotinamide), and Cu(2-MeSNic)2(Nia)(2).2H2O (where Nia is nicotinamide) and Cu(2-MeSNic)2L2 (where L is isonicotinamide, iNia, or ethyl nicotinate, EtNic) were tested on various strains of filamentous fungi by the macrodilution method. Most sensitive against copper(II) adducts with bioactive ligands were Rhizopus oryzae and Microsporum gypseum (IC50 1.5-2.3 mmol/L). The adducts with Nia, MeNia and EtNic at 5 mmol/L induced morphological changes in growing hyphae of Botrytis cinerea, mainly their intensive branching attached to release of cytoplasm with partial growth inhibition. Inhibition of sporulation (> 90%) of Alternaria alternata by Cu(2-MeSNic)2.H2O was observed as a change in the color of the colonies. The highest resistance was marked by B. cinerea and Fusarium moniliforme (average IC50 values 4.25 and 3.13 mmol/L, respectively). The presence of all bioactive ligands in copper(II) complexes caused an increase in the inhibition effect against model fungi (except significant inhibition activity of EtNic on R. oryzae).

Alternaria↗

PubMed2002

[Anti-yeast activity of ethanol extracts of Lilium candidum L].

The paper deals with anti-yeast activity of ethanolic extracts from the flowers and bulbs of Lilium candidum L., Liliaceae, as well as some compounds isolated from these extracts. Several different methods were used for the determination of anti-yeast activity: Lowry method of protein determination, dilution and cultivation method. The extract from the bulbs was shown to be more active than the extract from the flowers, while isolated compounds were inactive against the tested yeasts.

Antifungal Agents↗

PubMed2001

Copper complexes with bioactive ligands Part I--Antimicrobial activity.

Biological properties of new copper(II) complexes of 2-methylthionicotinate (2-MeSNic) of composition Cu(2-MeSNic)2(MeNia)(2).4H2O (where MeNia is N-methyl-nicotinamide), Cu(2-MeSNic)2(Nia)(2).2H2O (where Nia is nicotinamide) and Cu(2-MeSNic)2L2 (where L is isonicotinamide (iNia) or ethyl nicotinate (EtNic)) are reported. Gram(-)-bacteria (Escherichia coli) are more resistant against Cu(II) complexes than Gram(+)-bacteria (Staphylococcus aureus)--significant antistaphylococcal activity was found with Cu(2-MeSNic)2(MeNia)(2).4H2O (IC50 1.3 mmol/L). Candida parapsilosis was most inhibited by Cu(2-MeSNic)2.H2O and Cu(2-MeSNic)2(MeNia)(2).4H2O (IC50 1.4 mmol/L and 1.5 mmol/L, respectively). Biosynthesis of nucleic acids influenced by Cu(2-MeSNic)2(Nia)(2).2H2O indicated by incorporation of 14C-adenine (IC50(Ade) 0.31 mmol/L) is more sensitive than biosynthesis of proteins indicated by incorporation of 14C-leucine (IC50(Leu) 9.94 mmol/L). Cu(II) complexes with expressed antimicrobial activity showed no mutagenic activity.

Anti-Bacterial Agents↗

PubMed2001

Vegetative growth, aging- and light-induced conidiation of Trichoderma viride cultivated on different carbon sources.

The growth and conidiation of the aged Trichoderma viride culture grown in the dark, and after an induction by a light pulse, was examined in the presence of selected mono-, di(tri)saccharides, amino acids and alcohols as sole carbon sources. Hexoses and disaccharides, but not pentoses and amino acids, promoted proportionally both growth and conidiation induced by aging or light. All compounds but pentoses promoted the conidiation in aged cultures and photoconidiation in a close correlation. Ethanol, glycerol and ethylene glycol supported both growth and conidiation but these processes were not supported equally. Conidia formation with hexoses and amino acids as sole carbon sources seems to be a function of growth promotion, rather than of growth restriction (starvation, stress, aging). With glucose as sole carbon source the conidiation was not triggered by nutrient limitation, nor by the accumulation of waste metabolites. The aging-induced conidiation can be considered to be triggered by the genetic program of the microorganism rather than by its nutrient status.

Alcohols↗

PubMed2001

Differences in the microflora of scarified and unscarified seeds of Karwinskia humboldtiana (Rhamnaceae).

Seeds of Karwinskia humboldtiana obtained from a 1997 collection in the locality of Villa de Gracía Nuevo (León, Mexico) were contaminated with spores of filamentous fungi, bacteria and yeasts. The concentration of microorganisms in unscarified seeds ranged from 3.0 x 10(3) to 7.5 x 10(3) CFU/g. Predominant were bacterial isolates of the genera Aeromonas sp., Bacillus, and Pseudomonas; from filamentous fungi were identified Alternaria, Aspergillus niger, Cladosporium sp., Fusarium sp., Mucor sp., Penicillium commune, Trichothecium sp.; from yeasts Rhodotorula sp. and Saccharomyces cerevisiae. Seed scarification significantly reduced the microbial contamination. Of the original fungal isolates, only two were identified on scarified seeds, viz. Cladosporium sp. and Saccharomyces cerevisiae; although a relatively high incidence of a unidentifiable of Penicillium sp. was found, the bacterial spectrum was not altered. Treatment of scarified seeds with Vitavax 200 WP and Pomarsol Forte 80 WP (3 mg/g seeds) augmented germination by 10-19% compared to treated unscarified seeds, and by 16-31% compared to untreated unscarified seeds.

Bacteria↗

PubMed2001

Novel oxindole derivatives and their biological activity.

The antifungal activity of fourteen novel derivatives of oxindole with side chain was studied using representatives of toxinogenic, phytopathogenic and dermatophytic filamentous fungi. Derivatives with exocyclic C=C bond in position C-3 exhibited a higher antifungal activity compared with derivatives with an exocyclic C-C bond in the same position. The strongest antifungal effects were shown by 3-(-2-thienoylmethylidene)-indol-2(3H)-ones.

Antifungal Agents↗

PubMed2001

Glutamate decarboxylase activity in Trichoderma viride conidia and developing mycelia.

Glutamic acid decarboxylase (GAD) activity was measured in homogenates of conidia and both submerged and aerial mycelia of Trichoderma viride. The GAD activity in conidia had a temperature optimum at 30 degrees C and a pH optimum at pH 4. GAD was stimulated by EDTA (2 mM) and was insensitive to treatment with calmodulin antagonists calmidazolium (10 microM) or phenothiazine neuroleptics (60 microM). Cyclosporin A (up to 300 microM) partially inhibited GAD in the homogenate, but not in the supernatant obtained after centrifuging the homogenate. Attempts to release GAD activity from the homogenate using high ionic strength, detergents, or urea failed. Freezing-thawing led to the partial increase of activity in the conidial homogenate. These results indicate that GAD is a membrane-bound enzyme. The highest specific activity of GAD was present in the mitochondrial/vacuolar organellar fraction. Germination of conidia in the submerged culture led to a temporary decrease in GAD activity. After prolonged cultivation, the activity displayed quasi-oscillatory changes. The stationary state was characterized by a high GAD activity. The presence of gamma-aminobutyric acid in the submerged mycelia was demonstrated. In surface culture in the dark, GAD activity increased in a monophasic manner until conidia formation. The illumination of dark-cultivated mycelia by a white-light pulse caused a dramatic increase in GAD activity. Light-induced changes were not observed in mutants with delayed onset of conidiation. In the dark or upon illumination by light pulse, the increase of GAD activity preceded the appearance of conidia. Thus, GAD activity in T. viride is closely associated with its developmental status and may represent a link between differentiation events and energy metabolism.

Cyclosporine↗

PubMed2000

Some biological properties of new quinoline-4-carboxylic acid and quinoline-4-carboxamide derivatives.

The antimicrobial and morphogenetic effects of fourteen newly synthesized 2-substituted derivatives of quinoline-4-carboxylic acid and quinoline-4-carboxamide were studied using G+ and G- bacteria, yeasts and filamentous fungi. The highest antimicrobial effects were found with substituted quinoline-4-carboxylic acid derivatives. Quinoline-4-carboxamides only weakly influenced the growth of the tested microorganisms. Some derivatives of quinoline-4-carboxylic acid elicited profound changes in the morphology of hyphal tips of Botrytis cinerea, mainly their branching and the release of the cytoplasmic content. Quinoline derivatives, which elicited morphological changes, increased also the permeability of the plasmalemma of plant cells.

Anthocyanins↗

PubMed1996

New azidometalkojates and their biological activity.

Azidometalkojates of the general formula MX2 (M = Cu, Mn, Mg, Zn or Ni and X = 5-hydroxy-2-azidomethyl-4H-pyran-4-one) were prepared and tested for antibacterial, antifungal and cytotoxic effects. The mangan and zinc derivatives are not active against any the tested microorganisms. A weak antibacterial activity was found with the copper derivative. The strongest antifungal effects were shown by the nickel derivative while the highest cytotoxic effect on HeLa cells was manifested by the zinc derivative.

Anti-Bacterial Agents↗

PubMed1995

Antibacterial effect of substituted 4-quinazolyl-hydrazines and their arylhydrazones determined by a modified microdilution method.

Eight 4-quinazolylhydrazines and eleven their arylhydrazones have been tested for antibacterial effects and for structure-activity relationships by a modified microdilution method. The derivative 6-chloro-2-morpholino-4-quinazolyl-5'-nitro-2'-furylhydrazone++ + had the highest antibacterial effect, the MIC values being 100 mg/L for E. faecalis, 250 mg/L for S. aureus, 200 mg/L for P. aeruginosa and 350 mg/L for E. coli. The most effective derivatives were those with the benzene ring substituted with chlorine or methyl group in position 6 or 8 and with pyrimidine ring substituted with a secondary amine in position 2. The modified microdilution method did not give rise to any statistically significant deviations in the MIC values for ampicillin in comparison with reported reference collection values.

Anti-Bacterial Agents↗

PubMed1994

Structure-activity relationships of some 4-quinazolylthiosemicarbazides and their triazolo derivatives.

Eight 4-quinazolylthiosemicarbazides and nine of their structural analogues have been tested for antibacterial effects and for structure activity relationships. 9-Chloro-5-morpholino-1,2,4-triazolo[4,3-c]quinazoline-3-thione has demonstrated the highest antibacterial effect (MIC of 1 mg/L for E. coli and P. mirabilis and < 1 mg/L for S. aureus and B. subtilis). The most effective derivatives have the carbon aromatic ring substituted with chlorine and the pyrimidine ring with morpholine or with secondary amine group.

Anti-Bacterial Agents↗

PubMed1994

Antimicrobial effects of new 1-(1,2,4-triazol-1-yl)-acetanilides.

Fourteen synthetically prepared 1-(1,2,4-triazol-1-yl)acetanilides were tested for antimicrobial effect. None of the prepared derivatives influenced the B. subtilis, P. fluorescens nor the tested yeasts. Only the derivatives with substituents in positions para or ortho and para were biologically effective. The widest antimicrobial spectrum was manifested by the pentachloro derivative, which was effective with G+ and G- bacteria and with filamentous fungi.

Acetanilides↗