Risk factors associated with dog endoparasites infection spread in East Slovak Lowland.

This study aimed to determine the prevalence of endoparasites in dog feces from public places, investigate the occurrence of endoparasites in soil, and identify potential risk factors associated with the dog endoparasites infection spread in East Slovak Lowland - the region near the EU border with Ukraine. In a one-year study, a total of 803 dog fecal samples and 148 soil samples from public places were examined for the presence of endoparasite developmental stages. In general, 43.59 % of dog excrements were positive. Six different species of intestinal parasites were detected: Toxocara canis (22.65 %), Trichuris vulpis (14.07 %), family Ancylostomatidae (10.09 %), Capillaria aerophilla (5.60 %), Ascaris spp. (1.49 %). Altogether, 52.03 % of soil samples were positive for at least one endoparasites species. The occurrence of parasitic eggs in the soil was as follows: Ascaris spp. (37.16 %), Toxocara spp. (29.05 %), Trichuris spp. (29.05 %) %), family Ancylostomatidae (2.03 %) and Toxascaris leonina (2.03 %). The occurrence of endoparasites between the towns and villages varied significantly. The distribution of endoparasites in dogs and soil was affected by the population density, the minority people living in the studied territory, the number of people living in poor hygienic conditions with limited access to drinking water and the usage of sewerage. Persisting endoparasitic contamination of the environment in East Slovak Lowland forms a reservoir with zoonotic potential representing public and environmental health problems.

Structural basis of polycomb bodies.

The spatial organization of the cell nucleus into separated domains with a specific macromolecular composition seems to be the fundamental principle that regulates its functioning. Because of the importance of regulation at the nuclear level, the cell nucleus and its domains have been intensively studied. This review is focused on the nuclear domain termed the Polycomb (PcG) body. We summarize and discuss data reported in the literature on different components of the PcG body that could form its structural basis. First, we describe the protein nature of the PcG body and the gene silencing factory model. Second, we review the target genes of Polycomb-mediated silencing and discuss their essentiality for the structural nature of the PcG body. In this respect, two different schematic models are presented. Third, we mention new data on the importance of RNAs, insulator elements and insulator proteins for the structure of PcG bodies. With this review, we hope to illustrate the importance of understanding the nature of the PcG subcompartment. The structural basis of a subcompartment directly reflects its status in the cell nucleus and the mechanism of its function.

The role of telomeres and telomerase complex in haematological neoplasia: the length of telomeres as a marker of carcinogenesis and prognosis of disease.

Human telomeres (discovery of telomere structure and function has been recently awarded The Nobel Prize) consist of approximately 5-12 kb of tandem repeated sequences (TTAGGG)n and associated proteins capping chromosome ends which prevent degradation, loss of genetic information, end-to-end fusion, senescence and apoptosis. Due to the end-replication problem, telomere repeats are lost with each cell division, eventually leading to genetic instability and cellular senescence when telomeres become critically short. Stabilization of the telomeric DNA through telomerase activation, unique reverse transcriptase, or activation of the alternative mechanism of telomere maintenance is essential if the cells are to survive and proliferate indefinitely. Telomerase is expressed during early development and remains fully active in specific germline cells, but is undetectable in most normal somatic cells. High level of telomerase activity is detected in almost 90% of human tumours and immortalized cell lines. The hematopoietic compartment may develop genetic instability as a consequence of telomere erosion, resulting in aplastic anaemia (AA) and increased risk of myelodysplastic syndrome (MDS) and acute myeloid leukaemia (AML). Genetic instability associated with telomere dysfunction (i.e. short telomeres) is an early event in carcinogenesis. The molecular cytogenetic method telomere/centromere fluorescence in situ hybridization (T/C-FISH) can be used to characterize the telomere length of hematopoietic cells. This review describes recent advances in the molecular characterization of telomere system, the regulation of telomerase activity in cancer pathogenesis and shows that the telomeric length could be a potential clinical marker of hematologic neoplasia and prognosis of disease.

Nucleolus: the ribosome factory.

The nucleolus is a nuclear compartment and represents the most obvious and clearly differentiated nuclear structure seen in the microscope. Within nucleoli most events of ribosome biogenesis, such as ribosomal RNA synthesis, processing, and ribosome subunit assembly, take place. Several lines of evidence now show that the nucleolus has also numerous non-ribosomal functions. This review is focused on the recent progress in our knowledge of how to correlate the known biochemical processes taking place in the nucleolus with nucleolar structures observed in the microscope. We still lack detailed enough information to understand fully the organization and regulation of the processes taking place in the nucleolar sub-structures. However, the present power of microscopy techniques should allow for an in situ description of the organization of nucleolar processes at the molecular level in the years to come.

Reduction of genotoxic effects of N-nitrosomorpholine in human hepatoma cells and hamster lung cells by carboxymethyl chitin-glucan.

N-nitrosomorpholine (NMOR) belongs to the group of N-nitrosamines and represents a known hepatocarcinogen. Exposure to this compound is considered to be a potential health hazard to humans. There is, however, considerable evidence that the effect of many carcinogenic agents can be markedly influenced or altered by various natural substances. The objective of this study was to assess the DNA-protective and anticlastogenic effects of the derivative of a natural compound, carboxymethyl chitin-glucan (CM-CG), against genotoxicity of N-nitrosomorpholine (NMOR) in human hepatoma cells HepG2 and hamster lung cells V79 cultured in vitro. The exponentially growing cells were pre-treated during 24 h with three different concentrations of CM-CG (150, 750 and 1500 mg/ml) and then treated with different concentrations of NMOR. DNAprotective effects of CM-CG were evaluated by single-cell gel electrophoresis (SCGE, comet assay) and anticlastogenic effects by chromosomal aberration assay. At the SCGE assay a short-term (30 min) and at the chromosomal aberration assay a continuous treatment with NMOR was used. In both HepG2 and V79 cells pre-treated with CM-CG, a significant decrease of the percentage of DNA lesions induced by NMOR was observed along with a reduction of NMOR-induced chromosomal aberrations. We did not find any substantial differences between the genotoxic effects of NMOR on HepG2 and V79 cells, which have different histopathological origins and different levels of metabolizing enzymes. Three different concentrations of CM-CG exerted a similar protective effect against NMOR-induced DNA lesions and chromosomal aberrations in both HepG2 and V79 cells.

Nikkomycin Z counteracts Rylux BSU and Congo red inhibition of Saccharomyces cerevisiae growth but does not prevent formation of aberrant cell walls.

Rylux BSU and congo red bind to chitin, interfere with proper cell-wall assembly, and stimulate chitin synthesis by increasing, most probably, chitin synthase 3 (ChS3) levels in Saccharomyces cerevisiae. On the other hand, the antibiotic nikkomycin Z inhibits chitin synthesis competitively. As ChS3 is the critical target of nikkomycin Z, its effect was tested in cells inhibited in growth by Rylux BSU or Congo red. Nikkomycin Z counteracted this inhibition but did not counteract aberrant cell-wall formation. These results indicate that chitin synthesis stimulation is the key step in Rylux BSU and congo red inhibition and support the idea that increase in chitin synthesis represents a compensatory response to damaged cell-wall structure. As Rylux BSU and congo red bind to newly synthesized chitin, further damage is caused in the wall and the response works in this case contrariwise. Nikkomycin Z breaks this vicious circle by counteracting the chitin synthesis stimulation.