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Z Bozdech

Publications and source records attributed to Z Bozdech.

7 recordsLinked to original sources
PubMed1999

Protein transport in the host cell cytoplasm and ATP-binding cassette proteins in Plasmodium falciparum-infected erythrocytes.

The main interest of our experiments is the study of ATP-binding cassette (ABC) proteins in Plasmodium parasites and their infected host cells. Here, we report on results obtained by studying the plasmodial PfGCN20 ABC protein. Employing immunomicroscopy and cell fractionation techniques, we found that PfGCN20 is localized to multiple regions of the infected erythrocyte, including membranous and non-membranous compartments inside and outside of the parasite cell. PfGCN20 was found to complement the function of its yeast homologue Gcn20p by acting as part of the yeast translation regulatory pathway. These results open up several hypotheses about a possible biological function of PfGCN20, such as being a component of plasmodial translation regulation, or functioning as an ATP-binding subunit of a multimeric ABC transporter, or acting as a molecular chaperone-like enzyme contributing to the protein translocation across multiple membranes in infected erythrocytes. More experiments are presently being performed to fully understand the biological function of this protein, abundant in multiple compartments of erythrocytes infected with the Plasmodium falciparum malaria parasite.

ATP-Binding Cassette Transporters↗
PubMed1998

The human malaria parasite Plasmodium falciparum exports the ATP-binding cassette protein PFGCN20 to membrane structures in the host red blood cell.

PFGCN20 is a member of the ATP-binding cassette family of proteins that is closely related to the yeast translational regulator Gcn20p. We have generated a polyclonal antibody against the N-terminal region of PFGCN20 and studied the cellular localization of PFGCN20 throughout the erythrocytic life cycle of Plasmodium falciparum. PFGCN20 was found to be present at all stages and a pronounced export of PFGCN20 into the erythrocyte was observed in the trophozoite and schizont stages. In the indirect immunofluorescence assay, PFGCN20 was found to display significant colocalization with antigens detected by the monoclonal antibody 41E11. In contrast, there was only a minimal overlap of PFGCN20 localization with EMP2 and HRP2. Immunoelectron microscopy demonstrated a pronounced accumulation of PFGCN20 in the lumen of the parasitophorous vacuole and deconvolution fluorescence microscopy showed membrane association with selective regions of a tubovesicular network in the red cell. We also observed a concentration of PFGCN20 in electron-dense plaques just underneath the parasite's plasma membrane and an association of PFGCN20 with cytoplasmic vesicular structures within the parasite. The observed export of PFGCN20 and its association with the tubovesicular network in host red cells, may be indicative of the fact that PFGCN20 functions as ATP-binding subunit of an unknown multimeric ABC-transporter. The cytoplasmic localization of PFGCN20 in the parasite, however, suggests that the involvement of PFGCN20 in translational regulation or other cytoplasmic biological functions cannot be ruled out.

ATP-Binding Cassette Transporters↗
PubMed1996

Cloning and sequence analysis of a novel member of the ATP-binding cassette (ABC) protein gene family from Plasmodium falciparum.

We have employed oligonucleotide primers directed against the Walker A and B ATP-binding consensus motifs in a PCR-approach to clone a novel member of the eukaryotic ABC protein family of genes from Plasmodium falciparum. The novel gene is predicted to encode a 95.5-kDa protein with two ATP-binding folds each containing a Walker A and B consensus motif and an ABC protein signature sequence. The predicted protein is highly hydrophilic and contains numerous phosphorylation consensus sites but does not contain any potential membrane spanning domains. The gene is present on chromosome 11 and is expressed as a 3.3-kb transcript. The closest homologue with known function to the plasmodial gene is the yeast GCN20 gene which is part of the translation initiation pathway in amino acid starved yeast cells. We have therefore tentatively named the gene Plasmodium falciparum GCN20 homologue (pfgcn20). The pfgcn20 encoded Pfgcn20 protein is also highly homologous to a number of ATP-binding subunits of prokaryotic ABC transporters. We speculate that Pfgcn20 may be an example of a eukaryotic ATP-binding cytosolic subunit of a multipeptide ABC transporter.

ATP-Binding Cassette Transporters↗
PubMedDate not supplied

[Nonspecific bacterial spondylitis--an analysis of 32 cases].

With the decrease of tuberculous spondylitis non-specific bacterial spondylitis has got more importance. Regarding the difficult differential diagnosis between non-specific spondylitis, tuberculous spondylitis and tumor the question arises about the role of primary surgical procedure. 32 cases of the orthopedic departments of Brno and Lübeck are demonstrated, in whom surgical intervention has been chosen without exception (exposure with or without spondylodesis). In 19 cases the bacteriological and in all cases the histological findings ensured the diagnosis "non-specific bacterial spondylitis". Diagnostic proceedings corresponded to the descriptions in literature, x-rays (incl. tomograms) and scintigraphy had superior importance, CT had to show the expansion of the inflammatory process into the vertebral canal. Concerning diagnosis, course of disease and duration of therapy blood sedimentation rate and leucocyte count were the dominant parameters. Time of bed-rest and corset-wearing depends on clinical and laboratory findings, antibiotic treatment should be continued until mobilisation and normalisation of clinical and laboratory findings. In one case we had a grave complication during the operation (lesion of v. iliaca), apart from this healing up occurred in all cases within one year, in the course of which radiological stabilisation followed normalisation of clinical and laboratory parameters.

Bacterial Infections↗