Igor - Styriak

• MVDr., Ph.D.
• Researcher at Institute of Animal Physiology of the Slovak Academy of Sciences

Polyolefin (linear low-density polyethylene, LLDPE) was blended with date palm wood (DPW) powder to prepare composites with concentrations of filler ranging from 10 to 70 wt. %. The Young ´s modulus of the composites significantly increased with an increase in the filler content in the entire concentration range. The presence of the filler improved...

The purpose of this work was to investigate the phenomenon of microbial iron reduction in industrial minerals and materials. These materials are generally not pure, often associated with impurities usually in the form of Fe³⁺. In all cases, the presence of iron affects the colour and the physical properties of the mineral and therefore lowers their...

The important group of polymeric composites is represented by wood fibres, and natural fibres such as flax, hem, cotton, jute, banana, ramie, sisal, coir, and date palm fibres represent a minor part. However, both groups can be utilised as an effective filler material for the reinforcement of inorganic (such as concrete) and polymeric matrices. The...

The soil and sediment samples with different content of metals and clay minerals were investigated during bioleaching. The increasing of clay and metal concentrations with decreasing particle size were found both in contaminated soil and sediment. Heterotrophic bioleaching of the iron rich clay fractions from the soil and the sediment were evaluate...

Magnetic particles (MPs) are currently used as a suitable alternative for peroxidase in the construction of novel biosensors, analytic and diagnostic methods. Their better chemical and thermal stabilities predestine them as appropriate pseudo-enzymatic catalysts. In this point of view, our research was focused on preparation of simply and fast meth...

The purpose of this study was to leach Cu, Zn, As, and Fe from contaminated soil and sediment samples with indigenous heterotrophic bacteria isolated from the study sites. The sediment contained Fe in the form of goethite and low concentrations of other metals. The soil contained hematite and high concentrations of other metals. The environmental c...

Magnetic particles (MPs) are currently used as a suitable alternative for peroxidase in the construction of novel biosensors, analytic and diagnostic methods. Their better chemical and thermal stabilities predestine them as appropriate pseudo-enzymatic catalysts. In this point of view, our research was focused on preparation of simply and fast meth...

Four gut lactobacilli (Lactobacillus plantarum L5, Lactobacillus paracasei L81, Lactobacillus fermentum L 670 and Lactobacillus casei subsp. pseudoplantarum L.c.) were examined by particle agglutination assay (PAA) for their lectin-like binding activity after their cultivation on Rogosa agar and in MRS broth. Seven ECM (extracellular matrix) molecu...

During the last few decades, both ecological and economic interests have resulted in a more intensive utilisation of natural materials for the creation of new composites, and issues such as recyclability and environmental safety have become increasingly important for the introduction of new materials and products. The main group of these materials...

The worldwide prevalence of obesity more than doubled between 1980 and 2014. The obesity pandemic is tightly linked to an increase in energy availability, sedentariness and greater control of ambient temperature that have paralleled the socioeconomic development of the past decades. The most frequent cause which leads to the obesity development is...

The bioleaching processfor silicate industrial minerals using heterotrophic bacteria is a technology that has not beenapplied onindustrial scaleyet. The laboratory experimentsofiron mineral removal from quartz sands were verified during the second pilot-plant via bioleaching by usingbig bags. The composition of medium, pH, and concentration of oxyg...

Chelating agents, surfactants and many chemicals have been widely used for the extracting heavy metals from contaminated soil and sediment. The EDDS (S,S-ethylene-diamine-disuccinic acid), SDS (sodium dodecylsulfate) or Na4P2O7 (tetrasodium pyrophosphate) were studied as chemicals enhancing the metal extraction. However, by using of EDDS, metal exc...

Polyethylene (PE) belongs among the most widely used polymers in many industrial applications, such as in building, packaging or transport industry. Qatar is one of the largest producers of PE in the world. Composite laminates consisting of PE and metal materials, such as aluminum (Al) lead to an improvement of various mechanical and physical prope...

Polyethylene (PE) belongs among the most widely used polymers in many industrial applications, such as in building, packaging or transport industry. Qatar is one of the largest producers of PE in the world. Composite laminates consisting of PE and metal materials, such as aluminum (Al) lead to an improvement of various mechanical and physical prope...

Nanoindentation is an important method for the evaluation of the mechanical properties of small material volumes and thin films to applied loading. In this work nanoindentation was used for evaluation of nanomechanical changes on the poly(lactic acid) (PLA) films, which are widely used in industry due to unique properties (biodegradable, moisture,...

Enterococci (58) from faeces of rabbits of various age (from 2 months to 3 years) and 5 different rabbit farms were isolated and tested for survival in the presence of oxgall, lactic acid production, urease activity, resistance to low pH as well as their binding ability was tested. Fifty percent of enterococcal isolates were identified as Enterococ...

Abstract Limiting factor of PE application in healthcare is high susceptibility of polyethylene towards bacterial growth. For this reason, antibacterial treatment of PE foils using appropriate antibacterial agents was used in this work. Benzalkonium chloride and bronopol were selected due to their satisfactory antibacterial effect confirmed by appl...

In this study the PLA commercial film was used and treated with radio-frequency plasma in argon, respectively air atmosphere at a pressure oj 100 Pa for 10 minutes. Subsequently, the samples were subjected to nanoindentation analysis, which investigated the change in hardness and elastic modulus of modified and poristine films.

In this study, the bacteria were isolated from heavy metal contaminated environments, and the applicability of their ability to remove heavy metals from polluted environment was evaluated at a laboratory scale. We have identified species with the highest efficiency for the removal of zinc, lead and cadmium from the model solutions. The results of s...

Nowadays, probiotics are used in veterinary and human medicine as well as in nutrition with in-creasing frequency. Probiotics are defined as direct feed microbials or microbial cell preparations with a beneficial effect on the health and well-being of the host (Fuller et al., 1989; Nemcová et al., 1997). In contrast to human nutrition, where lactob...

In this work, a radiofrequency (RF) discharged plasma generated in air atmosphere by pressure 100 Pa has been used to modify PLA surface. PLA pressed samples were prepared from PLA granules in190'C. Before plasma treatment, the samples were subjected to vacuum for 48 hours, by temperature of 50"C. The RF plasma discharge was applied for 30,60,90, 1...

The bio-weathering of basalt, granite and gneiss was experimentally investigated in this study. These rock-forming minerals weathered more rapidly via the ubiquitous psychrotrophic heterotrophic bacteria. With indigenous bacteria of Bacillus spp. from sediments of Lake Baikal, we traced the degradation process of silicate minerals to understand the...

Silica sands of low quality contain free iron oxides, clay and silt. These impurities may be removed by biological leaching as well as by industrial washing. The fine fractions obtained from industrial washing of quartz sand from Šastín, Slovakia, with a higher content of iron-bearing minerals and clay minerals were used to study bioleaching of imp...

The biostimulation for iron mineral dissolution and reduction with chelators and organic source were investigated on ferrihydrite and quartz sands contaminated with iron minerals. The finding that bacteria can donate electrons to chelators has important implications for the removal of iron impurities from industrial minerals such as quartz sands. T...

Ten Bacteriocinogennic enterococci, isolates from chicken and rabbits, were examined for their binding of collagen, fibronectin, albumin and vitronectin in tubes with Nutrient broth No.2. For ECM binding examination, enterococci were grown in MRS broth under normal air conditions at 37°C. Individual strains expressed binding of selected glycoprotei...

Ultra-fine iron particles and clay minerals which coat quartz grains or are impregnated in silicate matrix are difficult to treat by conventional mineral processing methods. Treatment by basin water bioleaching in combination with electromagnetic separation can substantially improve the quality of quartz sands. The purpose of this in-situ study was...

Large Enterococcus faecalis F4 bacteriophage (described earlier) consisting of double-stranded linear DNA of approximately 60 kb was characterized. Library was prepared of its random DNA fragments and selected recombinants were sequenced. Three phage essential genes were characterized: DNA polymerase, replicative DNA helicase and a minor capsid pro...

Faecal samples of 122 horses (from farms in Slovakia) were examined to select enterococci to study their probiotic potential for their further use as additives. Each gram of faeces contained 1.0-5.0 cfu (log 10) of enterococci. Of the 43 isolates, 25 (58.1%) were identified as Enterococcus faecium, 3 strains were (6.9%) Enterococcus mundtii and one...

Enterococci from different free-living rodents were isolated and selected. The strains were genotyped and their antibiotic sensitivity and /or resistance, production of lactic acid, urease activity, the presence of enterocin structural genes, plasmid detection, and their binding ability to proteins were determined. Among 24 enterococcal strains, 17...

Purpose Some useful bacteria could be used regularly in mycotoxins biodegradation. It is a very good and ecological method, which was tested in experiments when lactobacilli were used. The paper aims to describe this. Design/methodology/approach Five strains of lactobacilli in experiments were shown, by direct enzyme‐linked immunosorbent assay (CD...

Naturally occurring quartz sands contain various iron and clay minerals which coat silicate grains or are impregnated in silicate matrix. Treatment by bioleaching in combination with electromagnetic separation can substantially improve the quality of quartz sands. Bacterial removal of smectite, kaolinite and illite can be used to expose the surface...

Naturally occurring iron oxides are often coated on silicate grains or are impregnated in the matrix in silicates of industrial importance. These Fe-rich impurities can be removed from industrial minerals such as granite through bioleaching. Heterotrophic bioleaching may substantially reduce the need of aggressive chemical bleaches treat industrial...

Carboxyl group-containing magnetic nonporous poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) (P(HEMA-co-EDMA)) microspheres were used for the isolation of polymerase chain reaction (PCR)-ready DNA from samples of Baikal sediments. DNA was isolated using the phenol extraction method or the Soil DNA Isolation Kit. The occurrence of false...

Bioleaching processes in combination with electromagnetic separation can substantially improve the quality of feldspar raw materials. Bacterial destruction of silicates is necessary for releasing intergranular spaces of silicate grains. These are often impregnated with iron minerals which can be subsequently removed by electromagnetic separation. B...

ČONKOV Á E., LACIAKOVÁ A., ŠTYRIAK I., CZERWIECKI L., WILCZINSKA G. (2006): Fungal contamination and the levels of mycotoxins (DON and OTA) in cereal samples from Poland and East Slovakia. Czech J. Food Sci., 24: 33-40. The cereal samples were taken immediately after harvest from the selected localities of Poland (45 samples) and East Slovakia (60...

Naturally occurring quartz sands contain various iron and clay minerals which coated on silicate grains or are impregnated in silicate matrix. Bioleaching processes in combination with electromagnetic separation can substantially improve the quality of quartz sands. Bacterial destruction of smectite is necessary for releasing undersurface spaces of...

Two bacteriophages (F5 and F6) were isolated from lysogenic Streptococcus bovis strains 46/2 and 59/2, respectively, after spontaneous induction. Both bacteriophages produced clear and small plaques (0.1-0.2 mm in diameter) on two host Streptococcus bovis strains (47/3 and 4/1) out of 12 tested. After UV-light induction, clear plaques of 1.0 -1.2 m...

Enterococci (58) from faeces of rabbits of various age (from 2 months to 3 years) and 5 different rabbit farms were isolated and tested for survival in the presence of oxgall, lactic acid production, urease activity, resistance to low pH as well as their binding ability was tested. Fifty percent of enterococcal isolates were identi- fied as Enteroc...

Sixty-two animal enterococci were examined for their binding of bovine fibrinogen, porcine fibronectin, bovine lactoferrin, bovine apotransferrin and human holotransferrin in the particle agglutination assay (PAA). Individual strains expressed binding of selected glycoproteins to various degrees (0, 1, 2, 3), whereas bovine fibrinogen binding of en...

Using two Bacillus spp. isolates (Bacillus megaterium bl1 and Bacillus mycoides bl2) mineral dissolution of sulphides and silicates was investigated by AAS (atomic absorption spectrophotometry) and microscopic techniques in order to determine bacterial effects on the extraction of elements from samples and morphological changes of mineral surfaces....

The purpose of this study was to assess the weathering of finely ground phlogopite, a trioctahedral mica, by placing it in contact with heterotrophic (Bacillus cereus) and acidophilic (Acidithiobacillus ferrooxidans) cultures. X-ray diffraction analyses of the phlogopite sample before and after 24 weeks of contact in B. cereus cultures revealed a d...

Two strains of lactobacilli (Lactobacillus acidophilus T-135 and Lactobacillus plantarum 4/97) were selected in order to study their inhibitory properties against frequent udder pathogens (Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus uberis, Salmonella enteritidis and Bacillus pumilus), their production of organi...

Quartz sand containing mineral impurities was subjected to bioleaching with Bacillus spp. strains and subsequent elutriation. Bioleaching of the sample removed visible Fe-bearing minerals that coated quartz grains. During the bioleaching, elements were dissolved from silicate minerals. Poorly crystalline Fe-oxides that sealed siderite nodules were...

Growth and metabolic activities of Bacillus cereus were found to cause the extraction of iron atoms from the octahedral position in mica in the kaolin sample (49%) and in the quartz sands sample (17%) after 3 months of bioleaching, while aluminium removal was only 5%. Mica destruction was detected in kaolin and quartz sands samples by X-ray diffrac...

Dissolution of aluminosilicates and Fe-oxyhydroxide minerals from granitic eluvium using bacteria of Bacillus genus was monitored with solution chemistry, granulometric and X-ray analyses as well as microscopic techniques to determine the effects of these bacteria on crystal surface and releasing mechanism of K, Si, Fe, and Al from minerals. Feldsp...

Three gut lactobacilli from piglets (Lactobacillus plantarum L 5, Lactobacillus paracasei L 81, Lactobacillus fermentum L 670) and Lactobacillus casei subsp. pseudoplantarum L.c.) from a calf were examined by microtitre plate binding assay for their lectin-like binding activity after their cultivation on Rogosa agar and in MRS broth. Three ECM (ext...

The aim of this study was to investigate extracellular matrix (ECM) and mucin binding of selected bacterial isolates with probiotic features in comparison with commercially used probiotic bacteria. ECM molecules were immobilized in microtitre plates (mucin and fetuin) or on the surface of latex beads. Porcine mucin was bound by all 13 probiotic str...

Anti-microbial activity of five different enterocins produced by ruminal and environmental enterococci against fecal bacterial isolates was tested. The majority of all 61 strains (80.4%) were inhibited by all enterocins used. The remaining strains were inhibited at least by one enterocin. The highest activity, 51,200 arbitrary units per ml-1 (AU ml...

This contribution provides an overview of literature data on the microbial binding and biodegradation of mycotoxins. These data and preliminary results from our own laboratory suggest that mycotoxin-bacterial binding or biodegradation is a realistic process and encourages the screening of bacterial strains and their biodegradation potential.

Fifty eight enterococcal isolates from wild herbivores were tested for their antibiotic sensitivity pattern and lectin-like binding of extracellular matrix (ECM) and serum proteins. Kanamycin resistance was very frequent; many multiresistant strains were also isolated. All isolates were sensitive to rifampicin. Resistance to gentamicin, novobiocin,...

Nine strains of staphylococci were examined for their antibiotic resistance and for binding of seven extracellular matrix (ECM) molecules (bovine mucin, porcine mucin, porcine fibronectin, bovine fibrinogen, fetuin, bovine lactoferrin and heparin) immobilized on latex beads in the particle agglutination assay. All nine strains were resistant to bac...

The presence of the fedA (gene coding F18 fimbriae) and genes coding STa and LTI enterotoxins and verotoxin Stx2v was determined in 30 E. coli strains isolated from weaned pigs with postweaning diarrhea (PWD) and edema disease (ED). The fedA gene was detected in 22 strains (73.3%). It was mostly associated with the presence of ST gene determinant (...

Enterococci and staphylococci, isolates from faecal samples of 46 different animals such as deer, chamois, Euro- pean bison, zebra, camel, antelope, gazelle, horse, and piglets were treated by nisin (concentration 1 mg/ml). Only two strains (SX38 and EA163), isolates from the faeces of deer were not inhibited by nisin under in vitro conditions. It...

Ten auto aggregating vaginal Lactobacillus strains (five of these strains were selected among isolates from sows' vaginal swabs and the other five among isolates from cows' vaginal swabs) were investigated for their ability to bind type I collagen (Cn-I). All 10 autoaggregating strains in the range of A570nm readings 0.118-1.806 bound to immobilise...

Several biodegradation experiments were carried out using 10 different yeast strains.Saccharomyces spp., Kluyveromyces spp. andRhodotorula spp. were tested for biodegradation of selected mycotoxins (ochratoxin A, nivalenol, deoxynivalenol and fumonisin B1) standardsin vitro. There was confirmed that some yeast strains are able to degrade some mycot...

Ten gut and ten vaginal Lactobacillus strains were investigated for their ability to bind type I collagen (Cn-I) and four selected gut lactobacilli were investigated for their binding to other extracellular matrix (ECM) molecules. Immobilized Cn-I (100 mg/L) in wells of microtitre plates was bound by all 10 autoaggregating vaginal strains and by 3...

Microorganisms may play an important role in the dissolution of silicate structure in the rock weathering process and in the genesis of clay minerals. Bacteria of Bacillus species are considered to be relatively active in this process. The samples from Horna Prievrana kaolin pit are characteristic by a high number of bacteria, especially of Bacillu...

A strong bias against GATC sites was observed in the genome of phage F4, a lytic Streptococcus bovis bacteriophage. Only three GATC sites were found within the 60.4-kbp genome of this phage. The comparative lack of GATC sequences within the F4 genome was probably not due to dam methylation, as no modification within this site was detected using met...

Thirty-three enterococcal strains and 10 Streptococcus bovis strains were investigated for their protein-binding cell surface components. Seven extracellular matrix (ECM) proteins were immobilized on Difco latex beads to detect these components on the surface of all enterococcal strains and eight non-autoaggregating S. bovis strains by a particle a...

Weathering of rocks generated large volumes of kaolin clays, quartz sands and micas, as well as other materials, especially iron and titanium oxides. Kaolin from the Vyšný Petrovec (Slovakia) deposit is an economically important raw material, however, the mined kaolin needs to be treated by removal of undesirable components - mica constituents and...

The influence of bacterial strains mixtures of Bacillus species on the structure of mineral samples in the form of polished sections and granulated products subsequently to ore dressing at the Banskfá Hodruša deposit was investigated. These bacterial strains were isolated from a mining dump near Banská Štiavnica and from a kaolin pit near Horná Pri...

Four gut Lactobacillus strains displaying the features which make them particularly promising for the preparation of probiotic products were investigated together with 5 fresh isolates and one collection strain of Lactobacillus plantarum for their ability to bind type I collagen (Cn-I). Immobilised Cn-I in microtitre plates was bound only by 3 stra...

All 81 strains of Staphylococcus species isolated mainly from animals express high surface hydrophobicity as a stable property upon cultivation on blood agar. Bovine lactoferrin, human vitronectin, human fibronectin, heparin, human and bovine serum albumin were immobilized on latex beads to detect protein-binding cell surface components of 67 non-a...

A Fusarium moniliforme strain recently isolated from a corn meal feed was investigated for a mycotoxin production by ELISA method. The investigations showed negative reactions for T-2 toxin, zearalenone, deoxynivalenol and moniliformin as well as confirmed the production of fumonisins by this strain. To ascertain a possible prevention effect of mic...

The resistance of Streptococcus bovis strain II/1, the producer of SbvI restriction endonuclease, to F4 phage infection was demonstrated by the double-agar-layer method. Despite the presence of restriction endonuclease SbvI which can cleave F4 phage DNA to numerous fragments in vitro, the evidence that adsorption inhibition is the most important de...

A new bacteriophage, designated F4, was isolated from the ruminal fluid of a calf. The host range of F4 phage was limited to five strains ofStreptococcus bovis out of ten tested on which clear plaques 0.6–1.2 mm in diameter were found. Bacteriophage F4 had an elongated head 75 nm long and 33 nm wide with a noncontractile flexible tail 100 nm in len...

Spores of Fusarium sacchari var. subglutinans isolated from broiler feed BR1 were obtained at an average concentration of 1.5/mg in 25% of tested samples. The spore concentration was increased from 1 to 100/mg of solid substrate (BR2; biscuit) or to 1/nL of Sabouraud broth after 3 weeks of cultivation. Mycotoxin analyses of these three substrates s...

Three Streptococcus bovis strains were tested in biotype assay and examined for the adherence to cells of rumen epithelium primoculture. The adherence pattern of ruminal streptococci in phosphate buffered saline at pH values ranging from 4.1 to 8.5 was determined. Our isolates of Streptococcus bovis strains adhered best at pH 7.0–7.3. To characteri...

The first isolation of Lactobacillus plantarum bacteriophages from ruminal fluid is reported. Three bacteriophages were characterized on the basis of plaque morphology, host ranges, stability, electron microscopic morphology and DNA restriction endonuclease digestion patterns. They formed clear plaques and are placed in group A of Bradley's scheme...

Six strains of rumen Lactobacillus and four Streptococcus bovis strains isolated from rumen wall and fluid samples were examined for the adherence to cells of primary and secondary cultures of ruminal epithelium (REC) prepared from sheep and calf. S. bovis adhered to the keratinized REC. Ruminal lactobacilli did not adhere. The presence of rumen la...

The last step of pathway of lysine biosynthesis by rumen bacteria was tested. The first measurements of DAP-decarboxylase activity and of lysine production by Megasphera elsdenii, Selenomonas ruminantium, Clostridium spp., Butyrivibrio fibrisolvens and Bacteroides succinogenes as well as the first attempts to increase the lysine production by rumin...

Five Streptococcus bovis strains (47/3, 59/2, 4/1, 46/2 and 44/9) isolated from calf ruminal fluid samples were examined for the adherence to cultured ruminal epithelium cells. Four strains (47/3, 59/2, 4/1 and 46/2) were able to attach to the cultured epithelial cells. However, S. bovis 47/3 strain attached to the target cells in significantly gre...

A method for the isolation of Streptococcus bovis bacteriophages from ruminal fluid of calves is described. Thirty to 2 x 10(3) phages per ml infecting Streptococcus bovis strains 4/1 and 47/3 were isolated directly from ruminal fluid. Two bacteriophages were characterized on the basis of plaque morphology, host ranges, electron microscopic morphol...

Bacterial assimilation reduction of iron in the treatment of non-metallics Natural non-metallics, including granitoide and quartz sands, often contain iron which decreases the whiteness of these raw materials. Insoluble Fe 3+ in these samples could be reduced to soluble Fe 2+ by bacteria of Bacillus spp. and Saccharomyces spp. The leaching effect,...

Dissolution of Iron During Biochemical Leaching of Natural Zeolite Natural zeolite, including clinoptilolite, often contains iron and manganese which decrease the whiteness of this sharp angular material.The biological treatment of zeolite enables its use as an substitute for tripolyphosphates in wash powders which have to comply with strict requir...