Összes szerző

Barkó Szilvia

az alábbi absztraktok szerzői között szerepel:

Barkó Szilvia
Direct binding of fluorescent vancomycin to MreB

Aug 29 - kedd

15:30 – 17:00

I. Poszterszekció

P03

Direct binding of fluorescent vancomycin to MreB

Beáta Longauer1, Emőke Bódis1, Zoltán Gazdag4, Miklós Nyitrai1,2,3 and Szilvia Barkó1,2,3

1 University of Pécs, Medical School, Department of Biophysics

2 MTA-PTE Nuclear-Mitochondrial Interactions Research Group

3 University of Pécs, Szentágothai Research Center

4 University of Pécs, Faculty of Sciences, Department of Molecular Biology and Microbiology

The discovery of antibiotics is one of the greatest discoveries in human history. It is also known that bacteria have developed a serious arsenal of weapons to resist antibiotics. As a result, despite the availability of many antibiotics with very different mechanisms of action, the number of antibiotic-resistant bacterial species is increasing. The result is a worldwide crisis which mankind currently seems powerless to tackle.

In our study we describe a novel potential target in bacteria, which is essential for bacterial survival. MreB, which has major role in organising cell wall synthesis and is found in every bacterium, can be inactivated with a MreB-specific drug A22. This target, although it affects a component of the cell wall, is fundamentally different from the antibiotics used so far.

In our studies, we confirmed the binding of Bodipy-vancomycin to the MreB protein by steady-state anisotropy measurements, which showed an affinity on the order of micromolar. The anisotropy further increased upon exposure to native vancomycin, confirming the previous observation that vancomycin molecules can form supercomplexes with each other and with target proteins. Our light-scattering measurements suggest that vancomycin, like other proteins, can induce aggregation of MreB, but this effect is not observed for ATP-bound protein. This supports our previous observations that nucleotide binding plays a crucial role in MreB stabilisation. Our microbiological and fluorescence microscopy results show that A22 promotes the uptake of vancomycin into cells, which may explain why a synergistic effect between A22 and vancomycin in inhibiting E. coli cell division is observed.

All these observations suggest that antimicrobials based on the mechanism of action of A22 could play a key role in the future in the fight against resistant bacterial strains.

Ujfalusi Zoltán
The effects of contrast agents on renal cell lines and on the actin cytoskeleton

Aug 30 - szerda

15:30 – 17:00

II. Poszterszekció

P33

The effects of contrast agents on renal cell lines and on the actin cytoskeleton

Szilvia Barkó1, Elek Telek1, Kinga Ujfalusi-Pozsonyi1 Gábor Hild1,2 and Zoltán Ujfalusi1

1 Department of Biophysics, Medical School, University of Pécs; Pécs, Hungary

2 Department of Medical Imaging, Clinical Centre, University of Pécs, Pécs, Hungary

Medical images may show some degree of contrast loss in most imaging techniques. In such cases contrast materials are the best tools to enhance the density and intensity of the given area. Nowadays, radiologists can choose from a wide range of contrast agents. The active material of these contrast media penetrates in cells and because of their limited ability of depletion these molecules can accumulate in cells of different tissues. In many cases, contrast agents are used in relatively high volumes, which places a heavy burden on kidney function. A few years ago, contrast agent treatment was identified as the third leading cause of hospital-acquired acute kidney injury (after surgery and hypotension), accounting for 12% of all cases. Today, ~5% of hospitalized patients who develop acute renal failure have normal renal function before contrast administration. We believe that contrast agents exert a significant proportion of their cell-damaging effects by affecting the actin cytoskeleton. The overview of the corresponding literature clarifies that the effects of the clinically applied contrast materials expressed directly on the actin cytoskeleton and its detailed molecular mechanisms are unknown. Our aim is to investigate all possible effects contrast materials can express on human renal cells and the actin protein inside, especially the dynamic organization/rearrangement of the actin network.

Our results clearly show that the applied contrast materials greatly affect the polymerization properties of actin. The examined contrast compounds changed other parameters of actin too and caused dramatic changes on the examined cell lines as well. The DSC results show significantly decreased thermal stability for the treated actin filaments.