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Dive into the research topics where Ján Kraic is active.

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Featured researches published by Ján Kraic.


Nova Biotechnologica et Chimica | 2014

Anthocyanins in Wheat Seed – A Mini Review

Michaela Havrlentová; Ivana Pšenáková; Alžbeta Žofajová; Ľubomír Rückschloss; Ján Kraic

Abstract Improving the micronutrients in food has become an important field of the Second Green Revolution. In recent years, minor bioactive compounds such as polyphenols, pigments and carotenoids, have attracted more and more interest from both researchers and food manufactures as health-promoting and disease-preventing effects in both in vitro and in vivo studies. One of plant pigments, wheat anthocyanins as plant phenolics are increasingly attractive as natural compounds positively affecting consumer´s health and condition moreover wheat is staple food source consumed usually daily. For a purple, blue, or red colour of wheat seed are responsible glycosylated cyanidins, delphinidins, malvinidins, pelargonidins, petunidins, and peonidins located in aleurone layer or pericarp, respectively. Other than white seed colour is not natural for common hexaploid wheat but this trait can be introduced from donors by aimed breeding programs. The way of wheat anthocyanins to provide positive effects for consumer´s physiology is limited due to their specific occurrence in seed parts usually removed during grain milling practice and lower stability during processing to foods


International Journal of Molecular Sciences | 2015

Biosynthesis of Essential Polyunsaturated Fatty Acids in Wheat Triggered by Expression of Artificial Gene

Daniel Mihálik; Lenka Klčová; Katarína Ondreičková; Martina Hudcovicová; Marcela Gubišová; Tatiana Klempová; Milan Čertík; János Pauk; Ján Kraic

The artificial gene D6D encoding the enzyme ∆6desaturase was designed and synthesized using the sequence of the same gene from the fungus Thamnidium elegans. The original start codon was replaced by the signal sequence derived from the wheat gene for high-molecular-weight glutenin subunit and the codon usage was completely changed for optimal expression in wheat. Synthesized artificial D6D gene was delivered into plants of the spring wheat line CY-45 and the gene itself, as well as transcribed D6D mRNA were confirmed in plants of T0 and T1 generations. The desired product of the wheat genetic modification by artificial D6D gene was the γ-linolenic acid. Its presence was confirmed in mature grains of transgenic wheat plants in the amount 0.04%–0.32% (v/v) of the total amount of fatty acids. Both newly synthesized γ-linolenic acid and stearidonic acid have been detected also in leaves, stems, roots, awns, paleas, rachillas, and immature grains of the T1 generation as well as in immature and mature grains of the T2 generation. Contents of γ-linolenic acid and stearidonic acid varied in range 0%–1.40% (v/v) and 0%–1.53% (v/v) from the total amount of fatty acids, respectively. This approach has opened the pathway of desaturation of fatty acids and production of essential polyunsaturated fatty acids in wheat.


Nova Biotechnologica et Chimica | 2014

Elicitation Phenolic Compounds in Cell Culture of Vitis vinifera L. by Phaeomoniella chlamydospora

Martin Sák; Ivana Dokupilová; Daniel Mihálik; Jana Lakatošová; Marcela Gubišová; Ján Kraic

Abstract The in vitro cell cultures of Vitis vinifera L. cv. St. Laurent were treated with two elicitors - synthetic methyl jasmonate and natural, prepared from grapevine plant infected with the Phaeomoniella chlamydospora, the agent causing the Esca disease of grapevine. Efficiency of phenolic compounds production after elicitation of cell culture was analysed immediately after treatment (15 min, 30 min, 60 min) and later (after 24, 48, and 72 hours). The cell growth and content of phenolic compounds (+)-catechin, (-)-epicatechin, p-coumaric acid, syringaldehyde, rutin, vanillic acid, and trans-resveratrol were analysed in cultivated cells as well as in cultivation medium. Pch-treatment increased production of total polyphenols the most significantly 15 min after the elicitation and in optimal time was 2.86 times higher than in nonelicited culture and 1.44 times higher than in MeJa induced cell culture.


Food Science and Biotechnology | 2013

A new high-molecular-weight glutenin subunit from the slovak wheat (Triticum aestivum L.) cultivar ‘Trebišovská 76’

Daniel Mihálik; Ľubica Nogová; Katarína Ondreičková; Marcela Gubišová; Jozef Gubiš; Edita Gregová; Ivana Dokupilová; Roman Drška; Ján Kraic

Historical and local varieties are an important source of genetic diversity in connection with the wheat baking quality. By analysis of DNA from the coding part of the genome of the Slovak regional wheat (Triticum aestivum L.) variety ‘Trebišovská 76’, differences in the Dy subunit composition coded by locus Glu-1D were found. Comparing the newly found sequence with a generally used 1Dy12 (GenBank accession no. X03041) sequence, existence of a new high-molecular-weight glutenin subunit, which was marked as 1Dy12* (GenBank accession no. EU266533) was confirmed. The molecular weight of probable protein coded by 1Dy12* subunit reaches 72.35 kDa comparing to the 1Dy12, which reaches 68.71 kDa. This difference is not likely to distinguish by SDS-PAGE. The easiest way for cereal genotyping according to baking quality is proteomic analysis. More exact and suitable method for genotype identification appears to be marker assisted selection using PCR.


Genetic Resources and Crop Evolution | 2005

Clustering of Chickpea (Cicer arietinum L.) Accessions

Klaudia Jomová; Michaela Benková; Mária Žáková; Edita Gregová; Ján Kraic

The variation in 20 morphological and agronomical traits has been evaluated in a set of chickpea genetic resources from four countries. Data indicated differences between accessions in leaf, flower, pod, and seed traits and characteristics, as well as in vegetation period. Multivariate analyses of these data segregated chickpeas into groups. Polymorphism in seed glutelines was absent, while variation in seed prolamines was very limited. DNA amplification patterns have been analyzed by semi-arbitrary primers and by specific microsatellite primers. Only some of semi-arbitrary primers generated usable DNA banding patterns, moreover interpretation of these patterns can be more or less difficult. On the contrary specific primers amplifying microsatellites at the specific loci generated unambiguous and reproducible differences between chickpeas.


Chemical Papers | 2017

Secondary metabolites, antioxidant and anti-proteinase activities of methanolic extracts from cones of hop (Humulus lupulus L.) cultivars

Tibor Maliar; Peter Nemeček; Eva Ürgeová; Mária Maliarová; Vladimír Nesvadba; Karel Krofta; Katarína Vulganová; Erik Krošlák; Ján Kraic

Contents of polyphenols, flavonoids, bitter acids, α-bitter acids, xanthohumol, desmethylxanthohumol, essential oils, antioxidant activities, and inhibitory activities against trypsin, thrombin, urokinase, and papain were analysed in methanolic extracts prepared from the hope cones. Significant differences between extracts from eight hop cultivars in all measured parameters were found. Two cultivars—Agnus and Vital—could be designated as the very special, all possessing high content of bitter acids, α-acids, essential oils, xanthohumol, and desmethylxanthohumol. The other two cultivars—Bohemie and Sládek—had interesting inhibitory activities against analysed proteinases. Differences between cultivars were also in content of total polyphenols, total flavonoids, as well as in antioxidant activity. All analysed hop cultivars developed originally for brewing contained also secondary metabolites with valuable biological activities related to health conditions associated with antioxidant status and some pathophysiological agents of proteinase character.


Chemistry & Biodiversity | 2015

Antioxidants, Enzyme Inhibitors, and Biogenic Compounds in Grain Extracts of Barleys

Tibor Maliar; Gabriela Slaba; Peter Nemeček; Mária Maliarová; Michaela Benková; Michaela Havrlentová; Miroslav Ondrejovič; Ján Kraic

The content of biogenic compounds and the biological activities of barley (Hordeum vulgare L.)‐grain extracts was evaluated. The sufficiently large and heterogeneous set of barley genotypes (100 accessions) enabled the selection of special genotypes interesting for potential industrial, pharmaceutical, and medicinal applications. Barley genotypes with the highest contents of phenols, phenolic acids, flavonoids, biogenic thiols, and amines, radical‐scavenging activity, as well as inhibitory activities of trypsin, thrombin, collagenase, urokinase, and cyclooxygenase were identified.


Biologia | 2013

Thermal and acido-basic stability of antioxidant properties of extracts from cereal and pseudocereal grains

Tibor Maliar; Mária Maliarová; Ján Kraic; Miroslav Ondrejovič; Ivana Pšenáková; Michaela Havrlentová

Beneficial effects of whole grains of cereals and pseudocereals and their fractions to human physiology are well known and broadly published. Especially secondary metabolites, dominantly from the category of phenolics (or polyphenols), beneficially influence the health physiology and/or prevent disease progress. Within the frame of this study, ten genotypes of four cereals or pseudocereals, respectively, were chosen for their antioxidant activity, determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and β-carotene-linoleic acid bleaching model (BCLM) mechanisms. Tested genotypes were selected from primary collection based on their antioxidant activity values, as well as higher level of flavonoids or phenolic acids. The stability of antioxidant properties after thermic, acidic, and basic treatments was evaluated. The oat cultivar Sirene and buckwheat cultivar Bogatyr expressed high level of the antioxidant activity, but they lost it due to all types of treatment. Oppositely, treatments increased antioxidant activities in some samples, especially in oat cultivar Maris Oberon, wheat cultivar Ines and Karolinum, or partially in barley cultivars Kompakt (after basic treatment) and Jubilant (acidic and basic treatments). The lack of the antioxidant activity could be observed due to destruction of the key compounds responsible for the antioxidant effect, whereas the increasing activity could be seen due to release of the aglycons from glycosidic forms after treatment. The stability of antioxidant properties could be a valuable parameter of the raw material for manufacturing special foods with functional properties.


Chemistry & Biodiversity | 2017

Antioxidant and Proteinase Inhibitory Activities of Selected Poppy (Papaver somniferum L.) Genotypes

Erik Krošlák; Tibor Maliar; Peter Nemeček; Jana Viskupičová; Mária Maliarová; Michaela Havrlentová; Ján Kraic

Poppy seeds (Papaver somniferum L.) belong to tasty food ingredients however, they should be considered also as valuable source of biologically active compounds. Content of selected metabolites, antioxidant and proteinase inhibitory activities were analyzed in vitro in extracts from seeds of fifteen poppy genotypes. Considerable variation in all parameters was detected within the set of analyzed poppy genotypes. The genotype Major expressed the highest antioxidant activity determined by all four methodological approaches (DPPH, ABTS, FRAP, RP). The genotype MS 423 exhibited the highest inhibitory activities against trypsin, thrombin and collagenase. Very specific position among all had the genotype Redy. Its grain extract reached significantly high levels in 9 out of 14 measured parameters (TPC, TFC, TTC, TAC, FRAP, RP, inhibitory activities against trypsin, thrombin, collagenase). Edible grains of poppy are valuable source of natural compounds which may be beneficial in pathological states associated with oxidative stress or increased proteinase activities.


Central European Journal of Chemistry | 2016

Antioxidant and protease-inhibitory potential of extracts from grains of oat

Erik Krošlák; Tibor Maliar; Mária Maliarová; Peter Nemeček; Peter Hozlár; Miroslav Ondrejovič; Michaela Havrlentová; Ján Kraic

Abstract The most of important crops cultivated for production of foods and feeds could be considered as plants possessing nutraceutical or medically interesting compounds, especially if can be eaten without processing. Chemical and biological parameters that were evaluated in 100 oat (Avena sativa L.) genotypes were others than those that are important in food and feed production. Contents of polyphenols and flavonoids, radical scavenging activity (DPPH), and inhibitory activities against five proteases (trypsin, thrombin, urokinase, elastase, cathepsin B) were analyzed in extracts from mature grains. The antioxidant activity (DPPH) correlated to the content of total polyphenols. Only a minority (15 from 100) of analyzed genotypes created separate subgroup with a high content of polyphenols, flavonoids, and high antioxidant activity. The best in these parameters were genotypes CDC-SOL-FI, Saul, and Avesta, respectively. Fifteen other genotypes assembled another minority subgroup (also 15 from 100) on the basis of their high inhibitory activities against tested proteases. The highest trypsin-, urokinase-, and elastase-inhibitory activities were in genotype Racoon, the best in thrombin-, and cathepsin B-inhibitory activities were genotypes Expression and SW Kerstin, respectively. Three oats genotypes – Rhea, AC Percy, and Detvan appeared in both subgroups.

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Marcela Gubišová

University of Constantine the Philosopher

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Lenka Klčová

University of Constantine the Philosopher

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Milan Čertík

Slovak University of Technology in Bratislava

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Miroslav Glasa

Slovak Academy of Sciences

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Ivana Dokupilová

Slovak University of Technology in Bratislava

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Katarína Šoltys

Comenius University in Bratislava

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Lukáš Predajňa

Slovak Academy of Sciences

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Nina Sihelská

Slovak Academy of Sciences

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