Polymerase chain reaction (PCR) is molecular diagnostic method which allows the identification of lactic acid bacteria used in food industry. In this work species-specific PCR primers (targeted on highly conserved 16S rDNA region) were used for identification of bacteria of species Streptoccocus thermophilus in 10 randomly commercially accessible fermented milk products and for identification of species Streptococcus thermophilus in 25 lyophilisates collected in Culture Collection of Dairy Microorganisms Laktoflora (CCDM, Tábor, Czech Republic). The PCR products (968 bp) were detected using electrophoresis in 1,2 % agarose gel. Bacterial DNA was isolated from crude cell lysates by magnetic carriers P(HEMA co GMA) containing carboxyl groups. DNA was reversibly bind on their surface in the presence of high concentrations of poly(ethylene glycol) (PEG 6000) and sodium chloride. Phenol extraction of DNA was used as control. Streptococcus thermophilus strains were identificated using PCR in all analysed samples.

Microbial DNA was isolated from lysed cells of Lactobacillus genus in probiotic products. Reversible adsorption DNA on the surface of carboxyl coated nonporous poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (P(HEMA-co-GMA)) magnetic particles and silicagel coated manganase Perovskite nanoparticles. DNA was adsorbed on the surface of the particles in the presence of 16 % poly(ethylenglycol) (PEG 6000) and 2 M sodium chloride (NaCl) concentrations. The adsorbed DNA was released from particles by low ionic strength TE buffer (pH= 8.0). The quality of isolated DNA was checked by spectrofotometric measurement and PCR amplification. DNA samples isolated using magnetic particles and phenol extraction method (control method) were PCR-ready. The DNA isolated from lysed cells of probiotic products was quantificated in real-time qPCR.

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.

Probiotic lactic acid bacteria (LAB) are very often used in food procesing industry, such as milk products, cheese and fermentsd salami production in nova days. In diploma thesis were tested symbiotic food supplements from different producers. Bacterial DNA was isolated from crude cell lysates of six food suplements by magnetic particles P(HEMA-co-GMA). PCR-ready DNAs were isolated. from all products The detection of Bifidobacterium bacteria identified by PCR was in agreement with those declared by the manufacturers. Magnetic particles with immobilized antibodies against Bifidobacterium were used in the next part of thesis. These particles were used for the isolation of target cells from two products with cell identification by genus specific PCR.

Extraction of nucleic acids is an important step for all molecular biological studies. The process of isolation of plant DNA is complicated due to the presence of polyphenols, polysaccharides and other metabolites. They can be co-isolated with DNA and act as PCR inhibitors. The aim of this study was to compare CTAB extraction procedure, Qiagen DNA easy kit, direct homogenization, carboxyl-functionalised magnetic non-porous HEMA based microspheres and combination of the above mentioned methods for DNA isolation from different plants. The DNA was evaluated regarding concentration, purity and amplification in PCR. All methods provided DNA that could be used in downstream PCR applications. However, there were differences regarding yield, purity, labour intensiveness and cost. Combination of direct homogenization and magnetic microspheres coated by carboxyl groups was isolated DNA from various plants and plant foods in a quality suitable for convectional PCR, real time PCR and restriction analysis. This method is fast, simple and does not require work with harmful substances.

This thesis is interested in isolation and identification of probiotic bacteria in three different probiotic products using polymerase chain reaction (PCR). DNA in quality suitable for PCR was isolated from crude lysates using three different types of magnetic microparticles and phenol extraction. Identification genera and species of probiotic bacteria was proven using genus and species specific PCRs. Results were in accordance with data presented by manufacturers.

Magnetically driven separation techniques using magnetic solid carriers are one of modern methods to speed up and facilitate the previously used separation and purification procedures. The use of magnetic particles in biology imposes strict requirements on physical, and chemical properties of the particles, including low toxicity, biocompatibility and non-interference with the chemical environment in diagnostics. The aim of this study was to evaluate carboxyl-functionalised magnetic non-porous P(HEMA-co-GMA), P(HEMA-co-EDMA), PGMA, silica-coated lanthanum manganese peroskvite La0.75Sr0.25MnO3 and thermosensitive poly(N-isopropylacrylamide) microspheres – P(NIPAAm) for DNA isolation from different types of complex food and environmental samples containing PCR inhibitors. The solid-phase reversible immobilisation (SPRI) of nucleid acids on microsphere surface and the release of adsorbed DNA were optimised. DNA from real samples (milk products and probiotic food suplements, mouse faeces) was apparently adsorbed on solid particles from the aqueous phase system composed of 16% PEG 6000 and 2M NaCl. The conditions of the subsequent release absorbed DNA to the elution buffer (pH of elution buffer, temperature and time of elution) were optimized. The quality of eluted DNA and the presence of target DNA were examined by PCR and q-PCR using domain-specific Bacteria and genus-specific Lactobacillus primer set. Real-time PCR was used for an estimation of the PCR interference by comparing the amplification efficiencies of purified DNA containing solid nanoparticles with the DNA standards free of any nanoparticles

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.

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.

Pancreatic cancer (PC) is extremely severe malignant disease with a five-year survival of less than 5%. Currently there is no reliable tool for the diagnosis of PC in its early stages. At the time of clinical symptoms most patients are in an advanced stage of the disease and the treatment does not usually have a significant effect. For these reasons emphasis is gradually shifting to the search for the suitable molecular markers for improvement of the diagnosis and assessment of the survival prognosis with respect to a possibility of surgical treatment. MiRNA represent one of the most promising markers, although, their examination in pancreatic tissue is a complicated process. One of the reasons is the very small amount of the source material coming from a fine needle biopsy. A second cause of problems is the subtle character of the pancreatic tissue resulting in significantly lower yields of molecular genetic analysis when compared to other epithelial tissues. An additional negative factor is heterogeneity of the tissue resulting in disproportionate representation of tumor cells within the sample. A suitable choice of procedures for isolation of nucleic acids (NA) and subsequent analysis including quantification of tumor cells is critical for accurate evaluation of the miRNA levels. This work is...