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Identification of the Slovak traditional cheese “Parenica” microflora
Published September 5, 2018
227-239

Numerous studies have demonstrated the higher accuracy, faster time-to-results and lower costs provided by MALDI Biotyper systems compared to classical methods. In this study, the culturable population of total count of bacteria, enterococci, coliforms bacteria, lactic acid bacteria (LAB) and microscopic fungi and yeasts from cow’s dairy prod...ucts was identified using the MALDI-TOF MS Biotyper. Altogether, 50 samples of the Slovak cheese “Parenica” were examined. Total numbers of bacteria were cultured on Plate count agar at 37 °C for 24–48 h, aerobically; enterococci were cultured on Enterococcus selective agar at 37 °C for 24–48 h, aerobically; coliforms bacteria were cultured on Violet Red Bile lactose agar at 37 °C for 24–48 h, aerobically. The LAB were cultured on MRS (Main Rogosa agar), MSE and APT agar at 30 °C in microaerophilic conditions. The microscopic fungi and yeasts were cultured on Malt extract agar at 25 °C for 5 days, aerobically. Isolated strains (total 669) were subjected to identification by the MALDI-TOF MS. Among total count the identified bacteria mostly were Acinetobacter baumannii, Bacillus cereus, Micrococcus luteus and Staphylococcus warneri. Escherichia coli and Enterobacter cloacae were the most abundant coliform bacteria representatives identified. Coliform bacteria included Citrobacter, Hafnia and Klebsiella. Altogether three genera belonged to the LAB – Lactobacillus, Lactococcus and Leuconostoc were identified with Lactococcus lactis, Lactobacillus plantarum, Lactobacillus coryniformis, L. fructivorans and Leuconostoc mesenteroides were considered as the dominated LAB species in dairy products. Among yeasts, Kluyveromyces lactis, Candida zeylanoides and Yarrowia lipolytica were among the most isolated.

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Examination of the usability of the MALDI-TOF method in sunflower genetic identity analyses
Published May 16, 2017
33-38

Economically, one of our most important crop is the sunflower. Regarding its production it is essential to use top quality seeds. As the conditions of seed certification and the certification parameters are regulated by laws and ordinances, it is highly important to farmers and seed producers to detect seeds of low quality or dubious origins....r>Nowadays, the examination of the cultivar homogenity of sunflower is based on a reference method of the International Seed Testing Association Rules International (ISTA), Chapter 8. This standard reference method uses ultrathin poliakrilamid isoelectric focusing gel electrophoresis (IEF-UTL, or simply IEF). With this work we have set out to compare the results of MALDI-TOF to the test results – used as reference results – achieved by this reference method. The aim is to develop a new, quick, cheap and reliable method. In this article I summarized the results of some of the experiments that will provide basis for my further work.
During our previous experiments we have concluded that out of four extracting agents we can get the most protein markers using NaCl acid buffer, 1 propanol buffer.

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Effect of allithiamine on the level of hyperglycaemia-induced advanced glycation end products
Published December 15, 2019
41-44

Diabetes mellitus is a rapidly growing public health burden in both developed and developing countries. Diabetes mellitus is accompanied by hyperglycaemia, which can cause tissue injury by several mechanisms. One of these is the formation of advanced glycation end-products (AGEs). In this study, the effect of allithaimine, a fat-soluble thiamin...e derivative, was investigated on hyperglycaemia-induced AGEs levels using human umbilical cord vein endothelial cells (HUVECs) as a hyperglycaemic model. HUVECs were isolated by enzymatic digestion, characterized by flow cytometer and treated 30 mM glucose plus allithaimine or thiamine or cell maintenance medium as control.  Allithiamine was synthesized and purified. The structure of the synthesized and isolated compound was verified by reverse phase HPLC and MALDI-TOF. AGEs were evaluated by ELISA. Collectively, our results indicate that allithiamine can reduce level of the hyperglycaemia-induced AGEs similar to thiamine.

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Development of seed analyses by means of various matrix solutions and the MALDI-TOF MS technique
Published May 23, 2019
53-57

The earth's population is growing steadily, currently accounting for about 7.3 billion people. Population growth causes food demand to rise, approximately 36 million people die each year due to starvation or related diseases. One solution to this problem is the continuous examination and development of the agricultural economy. In this study, m...atrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI -TOF MS) were used to analyse of sunflower, soybean and hemp. In order to analyse the protein of maize, this method has already been applied. However, for sunflower, soy and hemp, it is necessary to develop a sample preparation method. Choosing the optimal matrix solution for ionization the traget molecule is an essential part of developing the method. Our aim is to compare two different matrix solutions (α-HCCA, SA matrix), based on the properties (intensity, noise ratio, value of spectra) of the spectra.

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Comparison of sample preparation methods for the identification of Staphylococcus Aureus by MALDI-FOF MS
Published May 23, 2019
9-14

Coagulase-positive staphylococci include 3 species, Staphylococcus aureus, S. hyicus and S. intermedius. Of these three species, S. aureus is the most well-known human pathogen. S. aureus is part of the human and animal normal microbiota, however, it is capable of producing several staphylococcal enterotoxins (SEs) that cause intoxication sympt...oms of varying intensity in humans after consuming contaminated food. Selective media which are used for the determination of coagulase-positive staphylococci from foods are not able to identify isolates at a species. With the MALDI-TOF MS technique, we can identify S. aureus cheaper and faster than by using molecular methods. This paper describes the results of the study of the presence of coagulase-positive staphylococci and S. aureus in many food products, and the application of three sample preparation methods: direct sample preparation, formic acid suspension and ethanol extraction.

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