Down-regulation by nuclear factor kappaB of human 25-hydroxyvitamin D3 1alpha-hydroxylase promoter

1,25-(OH)(2) vitamin D(3) is important for calcium homeostasis and cell differentiation. The key enzyme for the activation of liver-derived 25(OH) vitamin D(3) is 25-hydroxyvitamin D(3) 1alpha-hydroxylase. It is expressed mainly in the kidney but also in peripheral tissues. A 1413-bp fragment of the 1alpha-hydroxylase promoter was cloned into luciferase vectors pGL2basic and pGL3basic. Sequence analyses revealed four base exchanges and three base deletions compared with the published sequence which were identically found in five control persons. In silico promoter analyses revealed 17 putative nuclear factor (NF)kappaB sites, 10 of which were found to bind NFkappaB in EMSA experiments. Cotransfection of NFkappaB p50 and p65 subunits resulted in dramatic reduction of the promoter activity of the full-length construct as well as a series of 5'-deletion constructs. Deletion of the farmost 3'-situated NFkappaB-responsive element almost abolished NFkappaB responsiveness. Treatment of human embryonic kidney 293 cells with sulfasalazine, a NFkappaB inhibitor, resulted in enhanced 1alpha-hydroxylase mRNA production. Down-regulation of 1alpha-hydroxylase promoter through NFkappaB signaling may contribute to the pathogenesis of inflammation-associated osteopenia/osteoporosis.     

Structural and functional characterization of cyst cells in Sarcocystis sp. (Sporozoa, Apicomplexa)

By means of light and electron microscopy, the structural pattern of muscle cysts (sarcocysts) was examined for the four species of the genus Sarcocystis: S. muris (from murine skeletal muscles), Sarcocystis sp. and S. fusiformis (from, respectively, heart and skeletal muscles of buffalo), and S. ovifelis (from ovine tong muscles). The orderly fashion of the interior of the cyst is attained by partitition of its space into numerous compartments with the involvement of the intermediate filaments. These, in their turn, are bound to each other by thin filaments to make eventually a common filamentous net. The net limits separate groups of cells referred to as cyst zoites. The common net of filaments and microtubules (when present) may be regarded not only as the organizer of the cyst interior cytoskeleton, but also as the main mechanism of substance transportation in various directions: from the host cell to the sarcocyst, and within or outside the cyst. The role of dedifferentiation, proliferation and differentiation processes is suggested in the establishment of the fixed sequence of events throughout the unidirectional development of cyst cells and their interaction, from precystic meronts to cyst merozoites (gamonts). Special attention is paid to metrocyte morphogenesis and functioning. In the present work, metrocytes subjected to apoptosis were recognized. It is suggested that phenomenon of programmed cell death in metrocytes may be associated with the control of cell number in mature and ageing sarcocysts.     

Effect of restricted feed intake and addition of vitamins B2 and B6 and folic acid on the liver concentration of zinc and copper in rats

The aim of the present study was to investigate the influence of nutritional deficiency and dietary addition of vitamins (B₂, B₆, and folate) on hepatic concentration of zinc and copper in rats. The experiment was performed on 260 growing male Wistar rats divided into 13 groups. Animals of 11 groups were fed isocaloric diets (14.7 MJ/kg) in which the 20% of energy was derived from protein. Another two groups of rats were offered diets with 9% or 4.5% of energy originating from protein. Animals of both mentioned groups and of the control group (20% of energy from protein) were offered diets ad libitum. The other 10 groups were offered 50% and 30% of the amount consumed in the control group. Eight groups, from those 10 restricted ones, were differentiated by dietary addition of vitamins B₂ and B₆ and folate (300% addition). Restricted feed intake did not affect the liver zinc concentration but significantly increased the copper concentration. The addition of vitamin B₆ decreased the liver Zn concentration. The highest liver Cu concentration was noted in rats offered restricted diets to only 30% of intake in the control group and high in vitamin B₂ and in rats supplemented with all of studied vitamins together. It suggests that vitamin B₂ had the strongest impact on liver Cu concentration in rats fed restricted diets.     

Localization of human chorionic gonadotropin beta subunit transcripts in ovarian cancer tissue

Recent studies demonstrated that besides placenta and malignant trophoblastic tumors, hCG and especially its beta-subunit is secreted by a varieties of tumors of different origin. The aim of the present investigation was to determine the expression pattern of human chorionic gonadotropin gene in ovarian cancer tissue. The study included 8 patients with epithelial ovarian carcinoma. The expression and distribution of hCGbeta mRNA was assessed by in situ RT-PCR method. The semi-quantitative assessment was performed using computer image analysis. Transformation of the images into the pseudocolour scale showed a clear difference in fluorescence intensity among individual cancer cells. The intensity of ISRT-PCR products corresponding with expression level of hCGbeta demonstrated that its production by individual cancer cells is different. In all studied specimens of the ovarian carcinoma tissue, cancer cells characterized by the presence of active hCGbeta gene were found, whereas noncancerous tissue demonstrated lack of the gene expression. Thus, the study clearly shows that the expression of hCGbeta is the feature of ovarian cancer tissue.     

Effects of cellulose, carboxymethylcellulose and inulin fed to rats as single supplements or in combinations on their caecal parameters

We compared the effect of diets containing different nondigestible carbohydrates: cellulose (C), inulin (IN) and carboxymethylcellulose (CMC) as single supplements or in dietary combination on caecal physiology of rats. Sixty male Wistar rats (Rattus norvegicus) were divided into five groups and for 4 weeks were fed a casein diet with the compared carbohydrates (4% of diet) or a combination of IN+C or IN+CMC (both 4+4%). Diet intake and FCR index remained unaffected by the treatments, whereas IN improved the body weight gain of rats compared to CMC. Compared to C group, all diets containing IN and CMC decreased the caecal pH as well as enlarged the caecum, thus increasing the weights of contents and tissue, especially upon CMC treatment. Rats given carboxymethylcellulose (CMC and IN+CMC groups) had watery caecal digesta, and some of them suffered from diarrhoea. In the case of CMC, the caecal enlargement was due to tissue hypertrophy and digesta accumulation mostly in response to an increased bulk of contents. Unlike C+IN, the dietary combination of CMC- and inulin-enhanced fermentation in the caecum of rats, however the proportion of acetate, propionate and butyrate was less beneficial. Compared to CMC, inulin gave a higher concentration of SCFA, especially of butyrate and propionate. The action of inulin in the caecum of rats could be pronounced by dietary treatment combined with CMC.     

Changes of GABA(A)receptor activation kinetics in hippocampal neurons cultured for different periods of time

Cell culture is a convenient model for pharmacokinetic studies, but during the culture period, GABA(A)receptors are likely to undergo different modulatory processes. In this study, the current responses to ultrafast GABA applications were recorded from patches excised from neurons cultured for either up to two days (short-term culture) or for more than two weeks (long-term culture). The dose-dependencies of the current rising phases revealed significant differences between the two groups. In the short-term cultures, the responses to both saturating and non-saturating GABA concentrations were slower than in the case of the long-term cultures. We conclude that the GABA(A)receptors in cultured neurons undergo profound kinetic changes involving the modulation of the binding reaction and transitions between bound states.     

Protective effect of vaccination with DNA of the H. Pylori genomic library in experimentally infected mice

Immunologically mediated protection against H. pylori infection is an attractive alternative to antibiotic treatment. We compared the efficacy of conventional protein vaccination with that of genetic vaccination against experimental infection with H. pylori in mice. For oral immunization, we used the recombinant peptide of an antigenic fragment of UreB (rUreB) or H. pylori-whole cell lysate antigens, and for genetic immunization, we used recombinant pcDNA and pSec plasmids inserted with the fragment of ureB or DNA of the H. pylori genomic library. Mice were challenged with the mouse stomach-adapted H. pylori Sidney Strain. The detection of gastric bacterial colonization was performed by real-time PCR of a 26-kDa Helicobacter-specific gene, and the presence of serum H. pylori-specific antibodies was determined using direct ELISA assay. The most effective treatment appeared to be oral vaccination with rUreB and either intramuscular or intradermal vaccination with DNA of the H. pylori genomic library. Intradermal genetic vaccination with genomic library DNA significantly increased the IgG antibody response. Our study revealed acceptable efficacies of genetic vaccination with DNA of the H. pylori genomic library.     

Prevalence of agglutinating antibodies against<Emphasis Type="Italic"> Listeria monocytogenes</Emphasis> in chicks of the white stork (<Emphasis Type="Italic">Ciconia ciconia</Emphasis> Linnaeus, 1758) in Poland

In 2002 and 2003, blood samples from white stork (Ciconia ciconia) chicks were examined for the presence of antibodies against Listeria monocytogenes. Listeria antibodies were detected in 121 (59%) of 205 chick samples. The probability of Listeria antibodies being present increased with chick age; chicks detected with Listeria antibodies were in better condition than those without the bacterium.     

Evolution by polyploidy and gene regulation in Anura

The evolution of the metazoa has been characterized by gene redundancy, generated by polyploidy, tandem duplication and retrotransposition. Polyploidy can be detected by looking for duplicated chromosomes or segments of orthologous chromosomes in post-polyploid animals. It has been proposed that the evolutionary role of polyploidy is to provide extra-copies of genes, whose subsequent alteration leads to new functions, increased biological complexity, and, ultimately, speciation. We review the theory of evolution by genome duplication, basing our arguments on findings from autopolyploid anurans and fish, undergoing post-polyploidy diploidization. We conclude that: 1) the high genetic variability of autotetraploid anurans is a result of tetrasomic expression, based on studies of isozymes and other proteins. 2) Epigenetic mechanisms mediate the reduced expression or silencing of redundant copies of genes in the regulation of gene expression of these tetraploids. This conclusion is based on data concerning ribosomal and hemoglobin gene activity. 3) Duplication of the genome may have occurred more than once in the phylogeny of the anurans, as exemplified by 4n and 8n Leptodactylidae species.