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Molecular identification of probiotic bacteria in milk products form commercial yoghurt cultures
Horňan, Samuel ; Fialová, Lenka (referee) ; Smetana, Jan (advisor)
Lactic acid bacteria are considered as an important group of bacteria with probiotic effects, which are being widely used in the food industry or pharmacology. Identification and characterization of important probiotic strains play an essential role in the validation of probiotic products for commercial purposes. Their identification using molecular-biology techniques (most commonly PCR method) is one of the standard tools in commercial operations and services. The aim of this bachelor thesis is a literature review of probiotics and probiotic strains as well as a summary of current knowledge about the use of molecular biology techniques for identification of these bacteria with probiotic properties in dairy products. The experimental part of this work verifies the presence of probiotic bacteria declared on selected commercial dairy products using the polymerase chain reaction (PCR) method.
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Detection of probiotic bacteria in milk diary food products using PCR technique
Krempaská, Vladimíra ; Fialová, Lenka (referee) ; Smetana, Jan (advisor)
Probiotic bacteria play an important role in a healthy lifestyle. They help the consumer maintain the balance of intestinal microflora and prevent the overgrowth of harmful bacteria. Accurate identification and characterization of these probiotic strains is essential for research and the food industry. For exact identification, the use of molecular biological methods is necessary, thanks to which it is possible to validate probiotic products for commercial use. In this bachelor thesis, the DNA of probiotic bacteria was isolated from available dairy products. Two methods of isolation were used to isolate bacterial DNA, both of them provided sufficiently concentrated and high-quality DNA for further analysis by polymerase chain reaction (PCR). The presence of the Bacteria domain, genera Lactobacillus and Bifidobacterium were proved. Finally, the presence of Lactobacillus acidophilus species was also detected in the products.
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Biofilm formation in probiotic cultures and its application in pharmacy
Ryšávka, Petr ; Obruča, Stanislav (referee) ; Vorlová, Lenka (referee) ; Márová, Ivana (advisor)
The work was comprehensively focused on the development of adhesive forms of probiotics in the form of a biofilm on combined carriers with a prebiotic component. The second part dealed with the influence of food on the multiplication and survival of selected types of probiotic bacteria. Subsequently, the effect of individualized probiotic supplements on changes in the human intestinal microbiome was monitored. Suitable adherent probiotic strains for biofilm formation were selected and tested. Methods have been introduced and different variants of carriers for culturing and binding bacteria have been tested. In vitro experiments verified the stability of biofilm stucture and its resistance to low pH, bile and antibiotics in comparison with the planktonic cell form. The antimicrobial effect of probiotic strains in the form of a biofilm was studied. The cultivation of the multispecies biofilm on the combined carrier was optimized and the stability of the biofilm and the final viability of probiotic bacteria were confirmed. Furthermore, the influence of various foods and beverages on the viability of probiotic bacteria was evaluated with emphasis on the simulation of passage through the gastrointestinal tract. Both models, solutions with standardised concentrations of alcohol, sugar, salts, proteins or different pH and different types of real foods and beverages were tested. The effect of food and beverages was tested on monocultures of Lactobacillus acidophilus, Bifidobacterium breve and on probiotic capsules containing a mixed culture of probiotic microorganisms. The survival of probiotics in various food matrices in the simulated gastrointestinal tract was quantitatively different. We managed to define foods suitable for supporting the multiplication of probiotic bacteria. A separate part of the work was focused on the targeted modulation of the intestinal microbiome by individualized probiotics that were prepared on the basis of molecular biological analyzes of the intestinal microbiome aimed at detecting the percentage of lactobacilli, bifidobacteria and phylum Firmicutes and Bacteroidetes. Personalized probiotic supplementation confirmed the positive effect of this approach on microbiome changes, especially on the increase of the content of lactobacilli, bifidobacteria and the overall diversity of the microbiome.
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Selective isolation of of the genus Lactobacillus bacteria from foods
Novotná, Eva ; Šárka, Havlíková (referee) ; Rittich, Bohuslav (advisor)
Probiotic lactic acid bacteria of genus Lactobacillus play an important role in the digestive tract of human. They are used in food processing and they are the part of food supplements. Lactic acid bacteria of the genus Lactobacillus can be identificated by polymerase chain reaction (PCR). Bacterial DNA was isolated from cell lysates of 4 synbiotic food suplements by magnetic particles P(HEMA-co-GMA). Isolated DNA was amplified by genus-specific and species-specific primers. Magnetic particles with immobilized antibodies against Lactobacillus bacteria were used in the next part of thesis. These particles were used for isolation target cells from products with their identification by genus specific PCR.
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PROBIOTIC GENES OF SIGNIFICANT LACTIC ACID BACTERIA IN FOOD
Konečná, Jana ; Ševčovičová,, Andrea (referee) ; Doškař, Jiří (referee) ; Španová, Alena (advisor)
Isolation of deoxyribonucleic acid (DNA) is an important step in the molecular diagnostics of microorganisms. A high quality of isolated DNA is necessary for DNA amplification by the polymerase chain reaction (PCR). The conventional DNA isolation using phenol chloroform extraction and DNA precipitation in ethanol is time consuming and requires the use of toxic phenol. Magnetic separation techniques using magnetic solid particles are one of modern methods to speed up the nucleic acids isolation. The aim of this work was to use two different types of magnetic particles for solidphase DNA extraction. The amounts of DNA in separation mixtures were measured using ultraviolet spectrophotometry (UV). The first experimental conditions were tested on chicken erythrocytes DNA. Phosphate buffer (pH 7, 7.6 and 8) was used for adsorption of DNA on magnetic particles. It was shown that approximately almost one half of DNA was adsorbed to the particles. The elution conditions of DNA were also optimized. Secondly, bacterial DNA was tested. This DNA eluted from the particles was in PCR ready quality. High resolution melting (HRM) curve analysis is a simple, low-cost method for amplicon discrimination and easy connection with real-time polymerase chain reaction (PCR). In this contribution, we report rapid species identification of strains belonging to the Lactobacillus group using HRM-PCR. Three different DNA isolation methods were used in this work: phenol extraction, separation using magnetic particles and commercial kit. Ten sets of targeted gene fragments primers (LAC1 – LAC2, LAC2 – LAC4, P1V1 – P2V1, Gro F – Gro R, 3BA-338f – Primer 1, V1F – V1R, CHAU - V3F – CHAU - V3R, CHAU - V6F – CHAU - V6R, poxcDNAFw – poxPromRVC, poxcDNAFw – poxPromRVT) were tested for amplification of the 16S rRNA gene. Use of GroF/R and LAC2/4 primers pairs successfully identify strains belong to the Lactobacillus group. The variance between used extraction methods for evidence of HRM curves was found.
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Identification of selected probiotic bacteria in food additives
Bubeníková, Lucia ; Španová, Alena (referee) ; Rittich, Bohuslav (advisor)
Bifidobacteria and lactobacilli are gram-positive bacteria which belong to the lactic acid bacteria group. They are ordinary constituents of gastrointestinal microflora, play a pivotal role in human nutrition and health, prevent pathogen colonization and maintain normal mucosal immunity. In present days they are used in production of functional food products and pharmaceutical additives. Polymerase chain reaction (PCR) is used to the detection and identification of bacteria which belong to the genus of Bifidobacterium and Lactobacillus. Specific primers for each genus are used in PCR reactions for in vitro amplification of definite part of DNA. In this work, total DNA was isolated from three additives (Pangamin Bifi plus, Biopron Junior and Probiodom) by the method of phenol extraction and amplified using genus-specific PCR primers giving amplicons of 523 bp (Bifidobacterium) and 250 bp (Lactobacillus). Occurrence of bacteria of both genera was proved in all of the three tested probiotic products.
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Molecular typisation of lactic acid bacteria
Jelínek, Zdeněk ; Ing. Špano Miroslav,PhD. (referee) ; Rittich, Bohuslav (advisor)
Lactic acid bacteria play important role both in food industry and health care. They are part of many fermented dairy products and gastrointestinal microflora. There is a whole variety of methods for bacteria identification, but we will focus on Rep-PCR and RAPD only. The aim of this work will be to discuss the impact of different correlation coefficients and cluster analysis algorithms on the results of taxonomic analysis.
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The application of magnetic particle for DNA isolation from selekted probiotic products for children
Vozárová, Petra ; Rittich, Bohuslav (referee) ; Španová, Alena (advisor)
In the food industry, it is important to correctly identify the species of bacteria and thier properties so that they can be used as a probiotic in dietary supplements. This is performed using DNA diagnostics. In the experimental part, the DNA from four probiotic dietary supplements for children was isolated. Magnetic particles P(HEMA-co-GMA) were tested for isolation. Isolated DNA was amplified by PCR and the presence of DNA of genus Lactobacillus, Bifidobacterium and Bacillus was demonstrated in the products according to the data declared by the manufacturer. The presence of species L.acidophilus, B.animalis in accordance with the data on the product has been demonstrated by PCR with species specific primers. Using PCR, the presence of L.casei, which was declared by the manufacturer, has not been proven in one product at given experimental conditions.
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Isolation of PCR-ready DNA from probiotic products for baby nutrition
Mantlová, Gabriela ; Havlíková, Šárka (referee) ; Španová, Alena (advisor)
The aim of thesis is focused on isolation of DNA in quality for polymerase chain reaction (PCR) and the identification of probiotic bacteria. From six probiotic supplements for children were isolated PCR-ready DNAs using magnetic carriers P(HEMA-co-GMA). Isolated DNA was amplified by genus-specific and species-specific primers. DNAs of Lactobacillus, Bifidobacterium and Streptococcus genera were identified as: L. acidophilus, L. rhamnosus, L. casei, B. bifidum, B. longum ssp. longum, B. breve, B. longum ssp infantis, B. animalis and S. thermophilus. The identification corresponded with the data declared by the producers.
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Use of Molecular Biology Techniques for Identification and Analysis of Probiotic Bacteria
Konečná, Jana ; Doškař, Jiří (referee) ; Kráčmar, Stanislav (referee) ; Obruča, Stanislav (advisor)
Isolation of deoxyribonucleic acid (DNA) is an important step in the molecular diagnostics of microorganisms. A high quality of isolated DNA is necessary for DNA amplification by the polymerase chain reaction (PCR). The conventional DNA isolation using phenol-chloroform extraction and DNA precipitation in ethanol is time-consuming and requires the use of toxic phenol. Alternative method of DNA isolation is use of commercially available kits which, however, are expensive and their efficiency is low. Magnetic separation techniques using magnetic solid particles are one of modern methods to speed up the nucleic acids isolation. The aim of this work was to use two different types of magnetic particles for solid-phase DNA extraction. Magnetic microparticles P(HEMA – co – GMA) containing –NH2 group and nanoparticles PLL, whitch contains polylysine. The amounts of DNA in separation mixtures were measured using ultraviolet spectrophotometry (UV). The first experimental conditions were tested on chicken erythrocytes DNA. Phosphate buffer (pH 7, 7.6 and 8) was used for adsorption of DNA on magnetic particles. It was shown that approximately almost one half of DNA was adsorbed on the particles. The elution conditions of DNA were also optimized. Secondly, bacterial DNA was tested. After optimalization, the developed method was used for DNA isolation from real food supplements. This DNA eluted from the particles was in PCR ready quality. High resolution melting (HRM) curve analysis is a simple, low-cost method for amplicon discrimination and easy connection with real-time polymerase chain reaction (PCR). In this thesis, we report rapid species identification of strains belonging to the Lactobacillus group using HRM-PCR. Three different DNA isolation methods were used in this work: phenol extraction, separation using magnetic particles and commercial kit. Ten sets of targeted gene fragments primers (LAC1 – LAC2, LAC2 – LAC4, P1V1 – P2V1, Gro F – Gro R, 3BA-338f – Primer 1, V1F – V1R, CHAU - V3F – CHAU - V3R, CHAU - V6F – CHAU - V6R, poxcDNAFw – poxPromRVC, poxcDNAFw – poxPromRVT) were tested for amplification of the 16S rRNA gene. Use of GroF/R and LAC2/4 primers pairs successfully identify strains belong to the Lactobacillus group. The variance between used extraction methods for evidence of HRM curves was found.
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