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  • Author: Barbora Kaliňáková x
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Barbora Kaliňáková, Daniela Hudecová, Peter Segľa, Martina Palicová and Jozef Švorec

Abstract

Probable mode of action of new copper complexes of 2-methylthionicotinate (2-MeSNic) of composition [Cu(2-MeSNic)2(H2O)2] and [Cu(2-MeSNic)2(MeNia)2(H2O)2]·H2O (where MeNia is N-methylnicotinamide) is described. Both partial growth inhibition of Candida albicans (IC50 ≥ 1.78 mmol·L−1, MIC ≥ 2.5 mmol·L−1) and leak of proteins into the extracellular space (more than 80 %) were observed in the presence of these copper complexes. The membrane damage was detected by staining with Hoechst 33342, propidium iodide and methylene blue. Ascorbic acid potentiated antifungal activity of copper complexes approximately seven-fold and induced the oxidative stress, respectively. The production of intracellular reactive oxygen species was visualized by dichlorofluorescein. Thiobarbituric acid-reactive substances were formed as a by-product of lipid peroxidation.

Open access

Juliana Šimončicová, Barbora Kaliňáková and Svetlana Kryštofová

Abstract

Filamentous fungi belonging to Aspergilli genera produce many compounds through various biosynthetic pathways. These compounds include a spectrum of products with beneficial medical properties (lovastatin) as well as those that are toxic and/or carcinogenic which are called mycotoxins. Aspergillus flavus, one of the most abundant soil-borne fungi, is a saprobe that is able growing on many organic nutrient sources, such as peanuts, corn and cotton seed. In many countries, food contamination by A. flavus is a huge problem, mainly due to the production of the most toxic and carcinogenic compounds known as aflatoxins. In this paper, we briefly cover current progress in aflatoxin biosynthesis and regulation, pre- and postharvest preventive measures, and decontamination procedures.

Open access

Eva Hybenová, Lucia Birošová, Kristína Nagyová, Júlia Štofirová, Nikoleta Šaková, Petra Olejníková and Barbora Kaliňáková

Abstract

The aim of this work was to evaluate presence and properties of lactic acid bacteria in the faeces of 240 volunteers with various nutrition habits (vegetarians versus meat-eaters). Lactic acid bacteria counts in all age groups were nearly 5 or 6 logarithmic orders. Significantly higher amounts were found in women. Subsequently, based on the age and dietary pattern of probands, four samples were selected for isolation of lactic acid bacteria and identification of isolates in order to assign them to bacterial species. About 80 lactic acid bacteria were isolated from the faeces of young (21-30 years) and older (51-60 years) vegetarians and meateaters. The identification of the isolates was based on their morphological and biochemical characteristics. Isolates belong to lactobacilli, bifidobacteria, enterococci and propionibacteria. Surprisingly, bifidobacteria were predominated in older age group. The following probiotic properties were determined: survival at low pH value, and bile salt hydrolase activity. All strains were negative in bile salt hydrolase activity, but their growth was not inhibited in the presence of bile. The results from the study of survival at low pH value showed considerable variability in both dietary groups regardless the age of probands. However, it can be concluded, that bacteria isolated from the samples of older probands were more sensitive to acid pH.