Binding of MmeI restriction-modification enzyme to its specific recognition sequence is stimulated by S-adenosyl-L-methionine.

Restriction endonucleases serve as a very good model for studying specific protein-DNA interaction. MmeI is a very interesting restriction endonuclease, but although it is useful in Serial Analysis of Gene Expression, still very little is known about the mechanism of its interaction with DNA. MmeI is a unique enzyme as besides cleaving DNA it also methylates specific sequence.

Expression and simple, one-step purification of fragile histidine triad (Fhit) tumor suppressor mutant forms in Escherichia coli and their interaction with protoporphyrin IX.

The product of human fragile histidine triad (FHIT) gene is a tumor suppressor protein of still largely unknown cellular background. We have shown previously that it binds protoporphyrin IX (a photosensitizer) which alters its enzymatic activity in vitro. Fhit, diadenosine triphosphate (Ap3A) hydrolase, possesses the active site with histidine triad His-phi-His-phi-His-phiphi.

Protoporphyrin IX interacts with wild-type p53 protein in vitro and induces cell death of human colon cancer cells in a p53-dependent and -independent manner.

Photodynamic therapy (PDT) of cancer is an alternative treatment for tumors resistant to chemo- and radiotherapy. It induces cancer cell death mainly through generation of reactive oxygen species by a laser light-activated photosensitizer. It has been suggested that the p53 tumor suppressor protein sensitizes some human cancer cells to PDT.

Tumor suppressor Fhit protein interacts with protoporphyrin IX in vitro and enhances the response of HeLa cells to photodynamic therapy.

Fhit, the product of tumor suppressor fragile histidine triad (FHIT) gene, exhibits antitumor activity of still largely unknown cellular background. However, it is believed that Fhit-Ap(3)A or Fhit-AMP complex might act as a second class messenger in cellular signal transduction pathway involved in cell proliferation and apoptosis. We demonstrate here for the first time that the photosensitizer, protoporphyrin IX (which is a natural precursor of heme) binds to Fhit protein and its mutants in the active site in vitro.

Genetic variability of hepatitis B virus isolates in Poland.

There is very limited knowledge about the genetic variability of HBV strains circulating in the population of Polish chronically infected HBV patients. The aim of this study was to analyse the phylogenetic relatedness and polymorphism in some functional domains of HBV genome among chronically infected patients from northern Poland. Fifty-one serum samples were included to analysis of HBV genomes due to the viral load sufficient for DNA preparation and sequencing.

Sequence-specific inhibition of duck hepatitis B virus reverse transcription by peptide nucleic acids (PNA).

Background/aims: Peptide nucleic acids (PNAs) appear as promising new antisense agents, that have not yet been examined as hepatitis B virus (HBV) inhibitors. Our aim was to study the ability of PNAs targeting the duck HBV (DHBV) encapsidation signal epsilon to inhibit reverse transcription (RT) and to compare their efficacy with phosphorothioate oligodeoxynucleotides (S-ODNs).

Methods: The effect of two partly overlapping PNAs targeting epsilon and of analogous S-ODNs was tested in cell-free transcription and translation system for DHBV RT expression.

Evaluation of Fas gene promoter polymorphism in cervical cancer patients.

Transduction of signalling through Fas receptor has been implicated in physiological regulation of apoptosis process as well as pathogenesis of various human diseases. The gene encoding Fas receptor contains single nucleotide polymorphism at -670 position, which influences the expression by different transcriptional efficiency of this gene. The aim of this study was to determine the distribution of -670 A/G Fas gene promoter polymorphism in cervical cancer patients and healthy control group in Poland in order to evaluate the potential association between Fas genotype and cervical carcinogenesis.

Application of electrophoretic methods for detection of protein-porphyrin complexes.

Simple methods for detection and isolation of protein-porphyrin complexes were elaborated in our laboratory. They are based on the separation of protein-porphyrin complexes in native polyacrylamide gel and measurement of their fluorescence, with the use of two detection systems: the commercially available Gel Doc(TM) 2000 system, and a system specially designed for the purpose of these investigations, concerning protein-porphyrin interactions. The fluorescent complexes can be electro-transferred from the gel onto PVDF membrane, eluted and analyzed in order to identify the protein interacting with porphyrins.

Genotyping of bacteria belonging to the former Erwinia genus by PCR-RFLP analysis of a recA gene fragment.

Genotypic characterization, based on the analysis of restriction fragment length polymorphism of the recA gene fragment PCR product (recA PCR-RFLP), was performed on members of the former Erwinia genus. PCR primers deduced from published recA gene sequences of Erwinia carotovora allowed the amplification of an approximately 730 bp DNA fragment from each of the 19 Erwinia species tested. Amplified recA fragments were compared using RFLP analysis with four endonucleases (AluI, HinfI, TasI and Tru1I), allowing the detection of characteristic patterns of RFLP products for most of the Erwinia species.