The role of bacterium Escherichia coli in the tumorigenesis of colorectal carcinoma

Colorectal carcinoma is a severe disease of colon. It belongs to the cancers with the highest incidence and also high mortality. In the process of tumorigenesis, there are applied various mechanisms, mainly DNA damage and subsequent reparation and inflammation. Gut microbiota plays an important role in development of the colorectal cancer influencing cancer microenvironment. Microbiota triggers inflammatory response or produces different toxins. The diploma thesis was aimed on the relation between the presence of cyclomodulin genes in the genome of individual strains of bacterium Escherichia coli and their genotoxic features. To follow direct influence of epithelial cells by microbiota, we used in vitro model. We chose E. coli as a model microorganism because it is common bacterium of human gut, moreover, as facultative anaerob it is easily cultivated. We used six strains of E. coli with different relation to the host organism including probiotic, comensal and pathobiont. In probiotic strains of E. coli (Nissle 1917 and O83), we detected less genes for cyclomodulins than in other strains. We did not observed significant differences in genotoxic features of the strains. Also, we did not detect any changes in viability, proliferation, activation of repair mechanisms or p53 fosforylation caused by..

Cytogenetic and molecular characterization of astrocytic tumors

Astrocytic tumours include a heterogeneous group of tumours with different histological features. Their diagnostics and classification could be difficult in some cases. Besides histological features of the neoplastic tissue genetic mutations in the tumour cells are important for the basic characteristic of the tumours. According to the histological and clinical characters tumours of the central nervous system are divided into several malignancy grades. Low-grade astrocytomas are the most common solid tumours of children. More malignant forms (mainly glioblastomas) represent a significant group of tumours of CNS of adult patients. IDH1, TP53, EGFR, PTEN typically belong among genes which carry mutations in the cells of astrocytic tumours. Mostly pilocytic astrocytomas are often connected with mutations of the BRAF gene which is a part of the mitogen activated protein kinase (MAPK) pathway. Many modern methods are used for the investigation of the mutations in the genome of the neoplastic tissue. PCR, real-time PCR and sequencing are the most important molecular methods. The most often used cytogenetic methods which are based on the hybridization of the DNA are FISH and microarray techniques. In some cases also immunological methods could be used. The correct diagnostics of the tumour and its..

Universal primers for plasmid detection and method for their relative quantification in phytoplasma-infected plants

Abstract Rep gene occurring in the majority of plasmids associated with phytoplasmas was selected as a target for real-time PCR together with single-copy Tuf gene from the phytoplasma genome. Rep-specific primers amplified products from host plants infected with phytoplasmas of groups 16SrI, -II, -III, -V, -X, and -XII. Relative concentrations of plasmids ranged depending on strain from 1-2 copies to several hundred copies per each phytoplasma studied. Primers targeting the rep gene are proposed for direct PCR detection of phytoplasma plasmids from experimental periwinkle host as well as from natural plant hosts