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Analysis of the composition of selected probiotic products by PCR-HRM
Tomanová, Barbora ; Španová, Alena (referee) ; Trachtová, Štěpánka (advisor)
This work was focused on the detection of probiotic bacteria in four different probiotic products (probiotic cream, probiotic tampons, oral probiotics and soy beverages with probiotics). The viability of the bacteria contained in the products was verified. Complex matrices of the products were used to isolate DNA in a quality suitable for the PCR method, followed by identification of the declared bacterial genus and species. Amplification was achieved with conventional PCR and real-time PCR, genus- and species-specific primers were used. Bacteria, of the genus Lactobacillus and Bacillus and bacterial species Lactobacillus pentosus, Lactobacillus rhamnosus, Lactobacillus fermentum and Lactobacillus gasseri, were proven to be within the products. Subsequently, the DNA from mixed bacterial species in the probiotic tampon were distinguished using PCR-HRM. Five sets of primers were used to test this. Two sets of primers (primers P1V1, P2V1 and V1F-HRM, V1R-HRM) were evaluated as the most suitable for resolution.
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Magteic particles and their applications in biotechnology
Knápková, Monika ; Konečná, Jana (referee) ; Trachtová, Štěpánka (advisor)
The thesis is focused on the magnetic particles which are used in several biotechnological applications. The theoretical part deals with the specific properties of these nanoparticles and materials of which the nanoparticles can be made. There are also mentioned some of the biotechnological applications of magnetic particles. During the experimental part, selected types of magnetic particles were used to isolate nucleic acid. The quality of the isolated DNA with respect to purity was evaluated using the polymerase chain reaction and its modifications. High resolution analysis (HRM analysis) was also used to verify the quality of the isolated DNA and to resolution Lactobacillus casei and Lactobacillus rhamnosus. DNA isolation using magnetic carriers was successful. Commercially available MPG microcarriers and magnetic microparticles Fkol 77ox were the most suitable. In terms of purity magnetic nanoparticles F79/L3-PLL were the most suitable for the DNA isolation. The resolution of bacterial strains of Lactobacillus casei and Lactobacillus rhamnosus was not successful.
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Identification DNA of Plant and Animal Species in Food by Polymerase Chain Reaction
Šmíd, Jiří ; Hanák,, Petr (referee) ; Timko,, Jozef (referee) ; Kuchta, Tomáš (advisor)
We were developing detection methods for three food allergens of plant origin. We used real-time PCR for soy detection in food oriented on gene lec, that is coding lektine specific for soy. On this target sequence were oriented PCR system with primers Le2F and Le2R and TaqMan probe Le2P. Detection limit (2,75 pg), practical detection limit (0,02 %), inclusivity and exclusivity were determined. Whole system were quantified. Real-time PCR for pistachio detection were based on primers and probe for gene COR. Detection limit (3,5 pg), practical detection limit (0,002 %), inclusivity and exclusivity were determined. For almond detection we were not succeed system, that fulfil all qualitative parametres.
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Applications of real-time PCR for characterization particles suitable for DNA isolation
Ondrejková, Martina ; Šálek, Petr (referee) ; Trachtová, Štěpánka (advisor)
The theoretical part of the diploma thesis was focused on core-shell type magnetic carriers, used mainly in medical, molecular-biological and biochemical applications. Encapsulation of the core is essential for these applications due to the decrease od non-specific protein adsorbtion, increase of biocompatibility and the possible functionalization of magnetic carriers. In the experimental part, the DNA (E. coli) was amplified by real-time PCR in the presence of poly(hydroxymethacrylate-co-glycidylmethacrylate) (P(HEMA-co-GMA)) magnetic carriers with/without carboxyl groups. The inhibitory effect of different concentrations of magnetic carriers in the PCR mixture was evaluated from the calibration curve parameter values obtained by regression analysis. The presence of a specific PCR product was verified by agarose gel electrophoresis. Most of magnetic carriers without carboxyl groups extinguished the fluorescence in the concentration range of 2,0 – 4,0 g.l-1 in the PCR mixture, without inhibition of DNA amplification - the carriers were biocompatible. Magnetic carriers with carboxyl groups extinguished the fluorescence in the lower concentration range (0,4 – 4,0 g.l-1 in the PCR mixture). Their inhibition of amplification was in the concentration range of 2,0 – 4,0 g.l-1 in the PCR mixture, from the concentration 0,8 g.l-1 in the PCR mixture, the inhibition did not occur and the carriers were biocompatible. The results do not depend on the characteristic properties of the magnetic carriers but on the presence of the carboxyl groups on the surface of the carrier and the degree of coverage of the magnetic core by the polymer. Real-time PCR has become an effective tool for studying magnetic core encapsulation and the influence of functional groups on the surface of the polymeric layer.
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Foodborne Staphylococcus Aureus: Identification and Enterotoxin Production in Milk and Cheese.
Hrušková, Vendula ; Španová, Alena (referee) ; Kmet,, Vladimír (referee) ; Kaclíková, Eva (advisor)
Onemocnění z potravin (alimentární onemocnění) vyvolaná bakteriemi jsou stále aktuálním tématem v celosvětovém měřítku. Abychom zajistili výrobu zdravotně nezávadných potravin, je potřeba nových poznatků o virulenci patogenů, které by doplnily již známé skutečnosti o jejich růstu a přeživání v potravinách. Také potřebujeme vyvíjet rychlé a citlivé metody na detekci těchto patogenů. Dizertační práce popisuje metodu na detekci S. aureus v potravinách, která je založená na PCR v reálném čase ve spojení s namnožením v selektivním médium. Dále pojednává o vlivu environmentálních faktorů na růst S. aureus a tvorbu enterotoxinů v mléce a sýrech. Vyvinuli jsme rychlou a citlivou metodu na detekci S. aureus v potravinách s použitím selektivního namnožení a PCR v reálném čase. Nově vyvinutá metoda umožnila detekci S. aureus na druhý den od přijetí vzorku. Tato metoda může být použita jako rychlejší, citlivějsí a vysoce specifická alternativní metoda ke konvenční mikrobiologické metodě. Zkoumali jsme vliv tří různých teplot, 8°C, 12°C a 20°C na růst S. aureus a tvorbu enterotoxinu D v pasterizovaném mléce a na růst, expresi genu sed a tvorbu enterotoxinu D v tekutém médiu s extraktem z mozku a srdce (BHI). Experimenty byly prováděny v malých skleněných fermentorech po 6 dní. Genová exprese byla sledována pomocí qRT-PCR a tvorba enterotoxinu D byla měřena pomocí imunologické metody ELISA. Růstová křivka v BHI měla stejný průběh při 20°C a 12°C, ale v při 12°C začal růst se spožděním. Při 8°C nebyl pozorován žádný růst. Růst S. aureus v mléce byl ve srovnání s BHI menší. sed mRNA byla detekována při 20°C po 4 hodinách a při 12°C po 7 hodinách a produkce enterotoxinu se objevila v exponenciální fázi růstu. V mléce se produkce SED při 20°C a při 12°C objevila dříve, ale celkové množství vyprodukovaného SED bylo nižší než v BHI. Při 8°C nebyla pozorována žádná produkce SED stejně jako v BHI. Dále byl zkoumán společný vliv nízké teploty 12°C a přítomnosti kompetitivní doprovodné mikroflóry pocházející ze surového mléka na růst S. aureus a produkci enterotoxinu v pasterizovaném mléce. Byl pozorován inhibiční účinek na růst a produkci enterotoxinů a vliv kompetice byl výraznější než vliv nízké teploty. Produkce enterotoxinu byla nízká a odpovídala růstu. Snížením množství doprovodné mikroflóry a zvýšením inokula došlo pouze k nepatrnému zvýšení produkce enterotoxinu. V další fázi byly dva různé typy sýrů zaočkovány S. aureus za účelem simulace sekundární kontaminace při výrobě sýrů. Vzorky byly odebírány v průběhu 4 týdnů. Kritické faktory jako jsou kompetitivní mikrofóra nebo pH, které jsou zodpovědné za regulaci virulence S. aureus byly sledovány. Snažili jsem se rozlišit situace při kterých: (i) není pozorován růst, ale objevuje se produkce enterotoxinu a (ii) dochází k růstu ale bez produkce enterotoxinu.
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Determination of selected red fruit species in plant-based food using multiplex PCR and instrumental methods
Vybíralová, Natálie ; Langová, Denisa (referee) ; Fialová, Lenka (advisor)
In many cases food is becoming the subject of adulteration, including fruit products that contain raspberries, strawberries and blueberries. This bachelor thesis is focused on the detection of strawberries, rapsberries and blueberries in model and commercial baby food products using multiplex PCR and HLPC. The theoretical part of this thesis is focused on composition of red fruits, their importance in human nutrition and especially about isolation of DNA from plant material. The aim of the experimental part of work was the analysis of selected commercial and model mixtures fruit purees containg raspeberries, strawberries and blueberries using instrumental and molecular biological methods. The results of these metods are compared. Commercial purees were bought in retail grocery shop. Model mixtures of these purees were prepared in our laboratory. DNA was isolated from fruit purees after and it’s amplifiability was comfirmed, it was successfully used in multiplex PCR to confirm the presence of raspberries, strawberries and blueberries in fruit purees. In the instrumental part, certain phenolic substences which are specific to red fruits were detected by HPLC in model and commercial mixtures.
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Application of the method PCR-HRM analysis to identify bacteria in foods and food supplements
Šurková, Alice ; Illková, Kateřina (referee) ; Trachtová, Štěpánka (advisor)
Theoretical part of the thesis was focused on foods and food supplements containing microorganisms, especially bacteria. Furthermore, the thesis deals with methods for identification of the bacteria, primarily polymerase chain reaction (PCR). The thesis also includes real-time PCR and is specially focused on high resolution melting analysis (HRM). During the experimental part, the DNA sample was isolated from a chosen probiotics product using magnetic microparticles. The concentration of the DNA sample was determinate and DNA was subjected to PCR with subsequent detection PCR products by agarose gel electrophoresis. To the results specify HRM analysis was then performed.
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Identification of DNA from plant foods using molecular techniques
Papala, František ; Langová, Denisa (referee) ; Němcová, Andrea (advisor)
The aim of this bachelor thesis is the identification of plant DNA in a complex matrix using molecular techniques. The work first focuses on a search of literature sources concerned with molecular techniques of DNA identification. Next, it deals theoretically with methods of isolation and characterization of plant DNA. Specifically, we shall work with blueberry DNA. In the experimental part, DNA from four commercial products was isolated and subsequently subjected to PCR and HRM analysis.
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The negative effect of raw foods due to possible microbial contamination
Šťastná, Martina ; Hlaváček, Viliam (referee) ; Němcová, Andrea (advisor)
Raw diet is the current trend in nutrition, mainly because of the consumption of a balanced diet with a high proportion of health benefits. The basis is the consumption of fresh foods that have not undergone a heat treatment exceeding 42 - 45 ° C. The topic of the bachelor thesis is the general characterization of raw diet, safety of possible microbial contamination and determination of important nutrients and active substances contained in raw products. There are described the most widespread types of meals, approximation of raw diet in terms of its advantages and disadvantages. Also, there are described the most important bacteria, yeasts and molds occurring on fruits and vegetables. By selected methods described in the theoretical part, some nutrients and active ingredients in raw stick samples were determined. The experimental part describes the procedures and principles for the determination of these substances, and last but not least, the real-time PCR methods, agarose gel electrophoresis and the method of sample inoculation for selective solid media that have brought closer the possibility of occurrence of undesirable microorganisms in raw bars and cake. Despite the large number of benefits of raw food consumption and products made from it, it is necessary to take care of its health also in terms of possible contamination by microorganisms. The risk is that the food is not free from unwanted microorganisms during preparation. This is the reason why the raw products are consumed in the shortest possible time after opening, because they become easily a nutrition source for different types of microorganisms due to their composition.
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Optimization of DNA isolation form yogurt cultures and their detection by RT-PCR
Šurková, Alice ; Němcová, Andrea (referee) ; Brázda, Václav (advisor)
The thesis has optimized DNA isolation from pure yoghurt cultures and yoghurt products. The isolated DNA was than subjected to RT-PCR analysis. In the first part of the thesis, DNA isolation from pure yoghurt cultures using a commercial kit was evaluated as more effective than isolation by phenol extraction and magnetic microparticles. To assess the quality and quantity of DNA obtained the spectrophotometric determination of concentration and purity and qPCR were used. DNA of a total of ten pure yoghurt cultures in a quality suitable for PCR was obtained using the commercial kit. In the second part of the thesis, bacterial DNA was isolated from yoghurt products using the same commercial kit with a previous sample washing by lysation solution. DNA of six yoghurt products was isolated this way. Furthermore, two packages of homemade yoghurt were mad of each product, of which DNA was isolated in the same way. DNA obtained from yoghurts was subjected to RT-PCR using six pairs of primers (V3_F a V3_R, V6_F a V6_R, V1_F a V1_R, GroHRM_F a GroHRM_R, UPF a UPR, P1V1 a P2V1) and using the pure cultures DNA as a positive controls. The results confirmed the presence of cultures declared in each yoghurt and their ability to multiply after inoculation into a new medium (milk).
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