Electrochemical template synthesis of protein-imprinted magnetic polymer microrods

A novel method for the electrochemical template synthesis of surface-imprinted magnetic polymer microrods for protein recognition is proposed. The polymer was electrodeposited into sacrificial cylindrical microreactors, the internal walls of which were previously modified with a target model protein, avidin, by simple physisorption. The electropolymerization was performed from a mixture of 3,4-ethylenedioxythiophene, poly(styrenesulfonate) (PSS), and PSS-coated superparamagnetic nanoparticles resulting in the formation of inherently electroconductive polymers confined to the volume of the microreactor. Here we show that: (i) the template synthesis within cylindrical microreactors results in polymer rods with dimensions matching that of the reactor, (ii) the incorporation of superparamagnetic particles induces magnetic properties that allow for efficient collection and manipulation of the microrods released from the microreactors in magnetic field even from dilute solution, and (iii) the protein coating on the internal walls of the microreactors is shown to generate molecular imprints on the surface of the polymeric rods. This latter property was demonstrated by comparative binding experiments of a fluorescent avidin derivative to the surface-imprinted and non-imprinted magnetic polymer microrods

Rapid and quantitative antimalarial drug efficacy testing via the magneto-optical detection of hemozoin

Emergence of resistant Plasmodium species makes drug efficacy testing a crucial part of malaria control. Here we describe a novel assay for sensitive, fast and simple drug screening via the magneto-optical detection of hemozoin, a natural biomarker formed during the hemoglobin metabolism of Plasmodium species. By quantifying hemozoin production over the intraerythrocytic cycle, we reveal that hemozoin formation is already initiated by ~ 6–12 h old ring-stage parasites. We demonstrate that the new assay is capable of drug efficacy testing with incubation times as short as 6–10 h, using synchronized P. falciparum 3D7 cultures incubated with chloroquine, piperaquine and dihydroartemisinin. The determined 50% inhibitory concentrations agree well with values established by standard assays requiring significantly longer testing time. Accordingly, we conclude that magneto-optical hemozoin detection provides a practical approach for the quick assessment of drug effect with short incubation times, which may also facilitate stage-specific assessment of drug inhibitory effects. © 2020, The Author(s)

Sensitive detection of Plasmodium vivax malaria by the rotating-crystal magneto-optical method in Thailand

The rotating-crystal magneto-optical detection (RMOD) method has been developed for the rapid and quantitative diagnosis of malaria and tested systematically on various malaria infection models. Very recently, an extended field trial in a high-transmission region of Papua New Guinea demonstrated its great potential for detecting malaria infections, in particular Plasmodium vivax. In the present small-scale field test, carried out in a low-transmission area of Thailand, RMOD confirmed malaria in all samples found to be infected with Plasmodium vivax by microscopy, our reference method. Moreover, the magneto-optical signal for this sample set was typically 1–3 orders of magnitude higher than the cut-off value of RMOD determined on uninfected samples. Based on the serial dilution of the original patient samples, we expect that the method can detect Plasmodium vivax malaria in blood samples with parasite densities as low as ∼5–10 parasites per microliter, a limit around the pyrogenic threshold of the infection. In addition, by investigating the correlation between the magnitude of the magneto-optical signal, the parasite density and the erythrocytic stage distribution, we estimate the relative hemozoin production rates of the ring and the trophozoite stages of in vivo Plasmodium vivax infections

Secondary Structure Prediction of Protein Constructs Using Random Incremental Truncation and Vacuum-Ultraviolet CD Spectroscopy

A novel uracil-DNA degrading protein factor (termed UDE) was identified in Drosophila melanogaster with no significant structural and functional homology to other uracil-DNA binding or processing factors. Determination of the 3D structure of UDE is excepted to provide key information on the description of the molecular mechanism of action of UDE catalysis, as well as in general uracil-recognition and nuclease action. Towards this long-term aim, the random library ESPRIT technology was applied to the novel protein UDE to overcome problems in identifying soluble expressing constructs given the absence of precise information on domain content and arrangement. Nine constructs of UDE were chosen to decipher structural and functional relationships. Vacuum ultraviolet circular dichroism (VUVCD) spectroscopy was performed to define the secondary structure content and location within UDE and its truncated variants. The quantitative analysis demonstrated exclusive alpha-helical content for the full-length protein, which is preserved in the truncated constructs. Arrangement of alpha-helical bundles within the truncated protein segments suggested new domain boundaries which differ from the conserved motifs determined by sequence-based alignment of UDE homologues. Here we demonstrate that the combination of ESPRIT and VUVCD spectroscopy provides a new structural description of UDE and confirms that the truncated constructs are useful for further detailed functional studies

Highly Sensitive and Rapid Characterization of the Development of Synchronized Blood Stage Malaria Parasites Via Magneto-Optical Hemozoin Quantification.

The rotating-crystal magneto-optical diagnostic (RMOD) technique was developed as a sensitive and rapid platform for malaria diagnosis. Herein, we report a detailed in vivo assessment of the synchronized Plasmodium vinckei lentum strain blood-stage infections by the RMOD method and comparing the results to the unsynchronized Plasmodium yoelii 17X-NL (non-lethal) infections. Furthermore, we assess the hemozoin production and clearance dynamics in chloroquine-treated compared to untreated self-resolving infections by RMOD. The findings of the study suggest that the RMOD signal is directly proportional to the hemozoin content and closely follows the actual parasitemia level. The lack of long-term accumulation of hemozoin in peripheral blood implies a dynamic equilibrium between the hemozoin production rate of the parasites and the immune system's clearing mechanism. Using parasites with synchronous blood stage cycle, which resemble human malaria parasite infections with Plasmodium falciparum and Plasmodium vivax, we are demonstrating that the RMOD detects both hemozoin production and clearance rates with high sensitivity and temporal resolution. Thus, RMOD technique offers a quantitative tool to follow the maturation of the malaria parasites even on sub-cycle timescales

ABC transzporterek vizsgálata emberi őssejtekben és a sejt-differenciálódás során = Expression and function of ABC transporters in human stem cells and during cell differentiation

A projektben az ABC (ATP-Binding Cassette) transzporterek kifejeződését és funkcióját vizsgáltuk emberi őssejtekben, valamint követtük a normális és daganatos sejtdifferenciálódás során bekövetkező molekuláris szintű változásokat. Elsősorban a gyógyszerek hatásában, anyagcseréjében, az ellenük kifejeződő rezisztenciában szereplő transzportereket, valamint a sejtmembrán lipid-anyagcseréjében szerepet játszó ABC transzportereket vizsgáltuk. A projekt fontos része volt az emberi embrionális őssejtek speciális tenyésztési és differenciálási módszereinek adaptálása, továbbfejlesztése. Az ABC transzporterek vizsgálata során igazoltuk, hogy a humán embrionális őssejtekben az ABCG2 a legjelentősebb xenobiotikum transzporter, a korai sejtdifferenciálódás során az ABCG2 kifejeződése először emelkedik, majd jelentősen csökken. Megállapítottuk, hogy az ABCG2 mRNS használata különbözik a tumorsejtekben, a differenciálódott szöveti sejtekben, illetve a nem-differenciálódott őssejtekben. Új, transzpozon-alapú módszereket dolgoztunk ki az őssejtek stabil genetikai módosítására, fluoreszcens riporter fehérjék bevitelére. Az ABCG2 és az ABCA1 fehérjék címkézett változatainak kifejezése lehetővé tette a transzporterek sejten belüli lokalizációjának követését. Részletesen elemeztük az ABCG2 multidrog transzporter szerkezet-funkció összefüggéseit, szubsztrátokkal jelentkező kölcsönhatásait, alkalmazásokat fejlesztettünk ki a gyógyszerhatások vizsgálatára. | In this project we have studied the expression and function of ABC (ATP-Binding Cassette) transporters in human embryonic and tumor stem cells and followed the changes during normal and tumor cell differentiation at a molecular level. We have focused on the investigation of ABC transporters involved in drug metabolism, cancer multidrug resistance and cellular lipid metabolism. An important part of the project was to establish and further develop proper laboratory conditions and methodologies for culturing and differentiating human pluripotent stem cells. When studying human ABC transporters in human embryonic stem cells we demonstrated the major role of the ABCG2 protein. We found that the expression of this transporter first increases, then greatly decreases during early stem cell differentiation. The use of mRNA was found to be different in the tumor cells, differentiated cells, and pluripotent stem cells, respectively. We have developed new, transposon-based methods for the stable genetic modification of pluripotent stem cells and for the expression of fluorescent reporter proteins. By using tagged versions of the ABCG2 and ABCA1 proteins we could follow the intracellular localization of these transporters. We have studied in detail the structure-function relationships and substrate interactions of the ABCG2 transporter and developed new assays for studying drug interactions

The local food system in the ‘genius loci’ – the role of food, local products and short food chains in rural tourism

This article investigates the roles that locally produced, processed and marketed food (Local Food System) play in rural tourism and local socio-economic development. It is the first account of a 3 years’ research project (LO-KÁLI) exploring a successful Hungarian rural tourism destination, investigating both the demand side (what attracts tourists to pay for premium products/services); and the supply side (what attitudes, norms, values keep producers in their business). We contrast the externally perceived image (‘genius loci’) of the region (‘Hungarian Provence’, together with its cultural landscape, gastronomy, and social and environmental sustainability) with the impacts of the current development process on the environment and the general wellbeing of the local economy and society in reality. This article presents some of the theories and the analytical framework underpinning our project, alongside preliminary results on how the elements contributing to tourist attraction are perceived by locals and by visitors to the region