In vitro study of AMP-deaminase from fish (Cyprinus carpio) treated with hydrolyzable tannins

AMP-deaminase (EC 3.5.4.6) is an enzyme responsible for stabilising adenylate energy changes. The properties of this enzyme are controlled by various ligands of hydrophobic nature. An investigation of enzyme activity alterations under the influence of natural phenolic acids (tannic, ellagic and gallic) which are soluble in water, could evidence the biological toxicity of these compounds. In our study purified AMP-deaminase isolated from white muscle of Cyprinus carpio was exposed to phenolic acids in the concentration range of 1 to 50 microM as well as to tannic acid in the presence of Cu2+ ions (5 microM). On the basis of the obtained results we can conclude that among the tested acids, gallic acid did not contribute to the change in AMP-deaminase activity, whereas ellagic acid diminished its activity at the highest concentration (50 microM). Tannic acid caused a significant decrease in the enzyme activity in comparison to control for all used concentrations. Cu2+ ions alone reduced the activity of AMP-deaminase for all studied concentrations. A combined action of a chosen Cu2+ ions concentration (5 microM) with tannic acid at the concentration higher than 2 microM resulted in a decrease in the enzyme activity, but for lower tannic acid concentration of 1 microM the activity of AMP-deaminase was stimulated. These experiments showed that tannic acid may stop free radical chain reactions only at low concentrations (1 microM) in the presence of Cu2+ ions (5 microM).     

Borrelia burgdorferi sensu lato infection in mosquitoes from Szczecin area

The aim of the study was to determine the level of infection in mosquitoes with spirochetes Borrelia burgdorferi sensu lato in the woody areas of Szczecin. The mosquitoes were collected from May to September 2003. The spirochetes, Borrelia burgdorferi s. l., present in mosquitoes were detected in mosquitoes with indirect immunofluorescence assay (IFA) using rabbit anti-Borrelia burgdorferi antibodies and goat anti-rabbit IgG marked with fluorescein isocyanate (FITC). A total of 1557 females and 58 males were collected. They represented the genera Aedes (63%) and Culex (37%). The infection level of the mosquitoes from the area studied amounted to 1.7%. The results of the present study confirm the potential of these arthropods to spread Lyme borreliosis.     

Immunochemical studies of Salmonella Dakar and Salmonella Telaviv O-antigens (serogroup O:28)

Salmonella Dakar and Salmonella Telaviv bacteria belong to serogroup O:28, which represents 107 serovars and possesses only the epitope O28. Salmonella Telaviv has the subfactors O28(1) and O28(2) , whereas S. Dakar has O28(1) and O28(3) . So far, only limited serological and immunological information for this serogroup is available in the literature. Knowledge of the structures of their O-polysaccharides and the immunochemical investigations performed in this work allowed to reveal the nature of subfactor O28(1) as attributed to the presence of 3-linked (or 3,4-disubstituted) α-d-GalpNAc in the main chains of S. Dakar and S. Telaviv O-polysaccharides. An explanation for the cross-reactions between Salmonella enterica O28 O-antigens and other Salmonella O-polysaccharides and their structural similarity to Escherichia coli O-serogroups is also given.     

Vitamin D receptor gene variability as a factor influencing bone mineral density in pediatric patients

To determine the relationship between the polymorphism of vitamin D receptor gene and the bone mineral density in children. The study group consisted of 395 children aged 6–18 years. All patients underwent genotyping using the PCR-RFLP method within polymorphic loci BsmI (rs1544410), FokI (rs2228570), ApaI (rs7975232) and Taq I (rs731236) of the VDR gene. The BMD (g/cm², Z score) and BMC (g, Z score) by DXA method, as well as Z scores of the BUA, SOS and Stiffness ultrasound parameters were evaluated. Based on densitometry results, children were divided into 3 groups: I—Z score ± 1.0; II—Z score from −1.1 to −2.0; and III—Z score ≤ −2.1. A control group numbering 294 children was used for the purpose of allele frequency comparisons. The occurrence of studied polymorphism alleles in the control group did not significantly differ from the values expected according to the Hardy–Weinberg equilibrium (p values: 0.1224 for BsmI; 0.5958 for TaqI; 0.0817 for ApaI; and 0.8901 for FokI). Allele a ApaI carrier status in group III children was associated with an increased BMD (x = 0.8 vs 0.69, p = 0.0296) and BMC value (x = 28.76 vs 22.14, p = 0.0565) in spine projection results, Stiffness (x = −1.12 vs −1.91, p = 0.0347) and SOS (x = −1.43 vs −2.27, p = 0.0319) ultrasound parameters. In group II, significantly increased SOS values (−1.13 vs −1.73, p = 0.0378) were noted in f (FokI) carriers. The presence of aa ApaI and ff FokI polymorphisms favours a higher bone mass and better bone structure (decreased bone mass loss) in the analysed group.     

The effects of garlic-derived sulfur compounds on cell proliferation, caspase 3 activity, thiol levels and anaerobic sulfur metabolism in human hepatoblastoma HepG2 cells

The aim of the present studies was to determine whether the mechanism of biological action of garlic-derived sulfur compounds in human hepatoma (HepG2) cells can be dependent on the presence of labile sulfane sulfur in their molecules. We investigated the effect of allyl sulfides from garlic: monosulfide, disulfide and trisulfide on cell proliferation and viability, caspase 3 activity and hydrogen peroxide (H(2)O(2)) production in HepG2 cells. In parallel, we also examined the influence of the previously mentioned compounds on the levels of thiols, glutathione, cysteine and cysteinyl-glycine, and on the level of sulfane sulfur and the activity of its metabolic enzymes: rhodanese, 3-mercaptopyruvate sulfurtransferase and cystathionase. Among the compounds under study, diallyl trisulfide (DATS), a sulfane sulfur-containing compound, showed the highest biological activity in HepG2 cells. This compound increased the H(2)O(2) formation, lowered the thiol level and produced the strongest inhibition of cell proliferation and the greatest induction of caspase 3 activity in HepG2 cells. DATS did not affect the activity of sulfurtransferases and lowered sulfane sulfur level in HepG2 cells. It appears that sulfane sulfur containing DATS can be bioreduced in cancer cells to hydroperthiol that leads to H(2)O(2) generation, thereby influencing transmission of signals regulating cell proliferation and apoptosis.     

Nitric oxide storage and transport in cells are mediated by glutathione S-transferase P1-1 and multidrug resistance protein 1 via dinitrosyl iron complexes

Nitrogen monoxide (NO) plays a role in the cytotoxic mechanisms of activated macrophages against tumor cells by inducing iron release. We showed that NO-mediated iron efflux from cells required glutathione (GSH) (Watts, R. N., and Richardson, D. R. (2001) J. Biol. Chem. 276, 4724-4732) and that the GSH-conjugate transporter, multidrug resistance-associated protein 1 (MRP1), mediates this release potentially as a dinitrosyl-dithiol iron complex (DNIC; Watts, R. N., Hawkins, C., Ponka, P., and Richardson, D. R. (2006) Proc. Natl. Acad. Sci. U.S.A. 103, 7670-7675). Recently, glutathione S-transferase P1-1 (GST P1-1) was shown to bind DNICs as dinitrosyl-diglutathionyl iron complexes. Considering this and that GSTs and MRP1 form an integrated detoxification unit with chemotherapeutics, we assessed whether these proteins coordinately regulate storage and transport of DNICs as long lived NO intermediates. Cells transfected with GSTP1 (but not GSTA1 or GSTM1) significantly decreased NO-mediated 59Fe release from cells. This NO-mediated 59Fe efflux and the effect of GST P1-1 on preventing this were observed with NO-generating agents and also in cells transfected with inducible nitric oxide synthase. Notably, 59Fe accumulated in cells within GST P1-1-containing fractions, indicating an alteration in intracellular 59Fe distribution. Furthermore, electron paramagnetic resonance studies showed that MCF7-VP cells transfected with GSTP1 contain significantly greater levels of a unique DNIC signal. These investigations indicate that GST P1-1 acts to sequester NO as DNICs, reducing their transport out of the cell by MRP1. Cell proliferation studies demonstrated the importance of the combined effect of GST P1-1 and MRP1 in protecting cells from the cytotoxic effects of NO. Thus, the DNIC storage function of GST P1-1 and ability of MRP1 to efflux DNICs are vital in protection against NO cytotoxicity.