Student Researchers' Society Topics

Co-supervisor: Dr. BÓDIS, Emőke

If you think- as you have learnt - that bacteria are simpler than eukaryotic organisms-you are wrong.

In the last decades it turned out that these tiny entities are much more sophisticated as it was imagined ever. They possess the homologues of the most important eukaryotic proteins and these homologues can present link between the ancestral and the phylogenetically higher organisms.

In our department you can investigate recombinant proteins which play essential role in the construction of the "bacterial cytoskeleton". To do that you are going to learn how to separate your target protein and you get opportunity to investigate it using different biochemical and spectroscopic methods, such as chromatography, photometry, fluorimetry, and high resolution microscopy.

Images: (left) Structure of the actin homologue protein MreB from Thermotoga maritima (PDB ID: 1JCG). (right) Filament system in Caulobacter crescentus.

Co-supervisor: Dr. HILD, Gábor

Some widely applied intravenous contrast agents penetrate in the cells and modify the structure of the actin cytoskeleton. The molecular mechanism and further effects of this process is unknown. Our research is focused on these important molecular issues and the possible pathological effects using wide variety of spectroscopic devices and microscopes.

During Student Researchers' Society work the undergraduate students do not only have the opportunity to perform the experimental work belongs to their research topic but they can have a look on all ongoing research at the Department of Biophysics and can acquire other laboratory technics and the application of biochemical, microscopic and different spectroscopy methods.

Co-supervisor: Dr. TAMÁS, Andrea

Dynamic rearrangement of the actin cytoskeleton (e.g., during some tissue degeneration and regeneration processes) occurs through complex coordination of actin-associated protein families. In our in vitro experiments, we study the members of such protein families, which play an essential role in various biological functions.

In the present research topic, we aimed to explore the potential role of pituitary adenylate cyclase activating polypeptide (PACAP) as a neuropeptide in cytoskeletal regulation. PACAP has been isolated on the basis of its activating effect on adenylate cyclase in the pituitary gland, but shortly after its discovery, it became apparent that its effect was much more diverse.

The presence of actin-regulating proteins and their pattern of appearance may be characteristic of various clinical diseases, and changes in the quality and quantity (in time and concentration) of regulatory proteins may have a significant effect on the processes of cytoskeletal regulation involved in pathological changes.

Since PACAP plays a key role in many physiological processes, as well as in pathological changes, our aim is to understand the underlying cytoskeletal regulatory mechanisms and to explore their functions.

Our tasks include the identification of proteins, development of purification methods, understanding of structure-function coordination, studying the effect of exogenously inserted proteins on the actin cytoskeleton, and the plasma and, if possible, cerebrospinal fluid (CSF, liquor) for endogenous biomarker identification.

Co-supervisor: Dr. SZATMÁRI, Dávid

We will use microscopic methods to visualise the erythrocytes and study their morphological changes. To detect them, we will use other biophysical analysis methods such as differential scanning calorimetry (DSC). In our DSC assays, we will perform thermal denaturation of samples using a SETARAM Micro DSC-III calorimeter and detect their membrane structural changes using electron spin resonance spectroscopy (EPR).

Buy et al. "Changes in red blood cell membrane structure in type 2 diabetes: a scanning electron and atomic force microscopy study" Cardiovasc Diabetol, vol. 12, no. 1, 2013. doi:10.1186/1475-2840-12-25

The actin filament system (microfilaments) is a dynamic scaffold involved in such important cellular processes like cytokinesis, cell division, vesicle transport or malignant phenotype formation. The assembly-disassembly cycles, organization, function and connections of the actin filaments are regulated by a large number of actin binding proteins, creating intricate operational interactions. The actual array of the binding partners with the actin filaments together form microfilament subpopulations of specific cellular roles. The aim of the present research in our institute is to in vitro express actin binding proteins (like tropomyosin isoforms, gelsolin, cofilin, twinfilin, caldesmon, myosins etc.) in order to study their interactions with other actin-binding partners and their effects on the actin dynamics, possibly revealing the features of the individual filament populations. The measurements will be carried out after fluorescent labelling by spectroscopy methods and light microscopy. We also intend to express fluorescent proteins, labelled at specific sites, even in living neurons. The student will have the opportunity to acquire substantial expertise in various methods from protein cloning through molecular biology techniques to the above mentioned measurement procedures.

In the Department of Biophysics at University of Pécs our research group studies mainly the structure, molecular dynamics and interactions of cytoskeletal proteins with actin in the center of interest. Our research includes membrane nanotubes, which is a relatively new and highly interesting way of direct cellular communication. Membrane nanotubes are long, temporary membrane protrusions, providing more than physical connections between cells. Membrane nanotubes are described as direct communication pathways between certain cells (T-lymphocyte, neuran cells, kidney cells, myeloid cells, some cancer cells) transporting different matters or chemical signals. In the last few years nanotubes have quickly gained interest demonstrating a capability to spread disease among cells avoiding activation of immune system. Viruses, prions, different cell organelles, membranesurface proteins, lipids have been identified to migrate between cells using membrane nanotubes.

Our aim to reveal molecular processes and interactions in the formation and function of membrane nanotubes.

Figure: Mouse B-lymphocyte (A20) cells (fixated), labeled by Alexa 488 phalloidin, (63x magnification, SIM: structured illumination microscopy image). Arrow indicates a membrane nanotube.

Co-supervisor: Dr. BARKÓ, Szilvia

This Student Researchers’ Topic is a good possibility for students to participate a collaborating project between clinics and basic science researcher lab. Our clinical partner are Prof. Dr. Miklós Koppán, full professor, clinical director and Dr. Szilárd Papp senior clinical lecturer from the Department of Obstetrics and Gynaecology. We are studying expressed and purified actin and p53 apoptotic factor binding proteins effect on shape, division and movement of epidermal cells from cervical cytology samples. In HPV less, infected and treated patients. Mainly, microscopy, cell manipulation and in vitro methods are avaiable to study the malignus transformation of cancer cells on the level of cytoskeletal system.

Our research group studies membrane nanotubes, which is a relatively newly discovered, highly interesting way of direct cellular communication. Membrane nanotubes are long, temporary membrane protrusions, providing more than physical connections between cells. Membrane nanotubes are described as direct communication pathways between certain cells (T-lymphocyte, neural cells, kidney cells, myeloid cells, some cancer cells) transporting different matters or chemical signals. As a result of significant researches, viruses, prions, different cell organelles, membrane surface proteins, lipids have been identified to migrate between cells using membrane nanotubes.

Our aim to reveal molecular processes and interactions in the formation and function of membrane nanotubes by the application of superresolution microscopy.

Superresolution microscope techniques have been applied only in the last few years in different research fields. Denomination of these instruments originates from their exceptionally good resolution cabability. The Zeiss Elyra-type superresolution microscope found in the Szentágothai Research Centre at University of Pécs has 100 nm resolution, giving twice better resolution than traditional microscopes. A great advantage of this microscope and operation method (SIM, structured illumination) is not only the excellent resolution, but in contrast with other superresolution techniques it does not require special fluorophores, therefore sample preparation is easy.

Figure: Murine B-lymphocyte (A20) cells (living), labeled by DiO lipophilic membrane tracker, (63x magnification, SIM: structured illumination microscopy image). Arrow indicates a membrane nanotube.

Actin is the most abundant protein in eukaryotic organisms. The actin molecule is reversibly organized into filaments. One of the main constituents of eukaryotic cells, the actin cytoskeleton system, consists of dynamically organized actin filaments. The actin cytoskeleton plays a key role in various cellular processes, such as cell movement, morphogenesis, membrane transport and cell division. The organization of actin filament networks is regulated by a series of actin-binding molecules, and in the case of xenobiotics it is influenced. A detailed understanding of actin-based cellular processes requires knowledge of the conformational and dynamic changes occurring within actin.

During our research, we examine the mechanism of action of various xenobiotics (e.g. small toxin molecules) or proteins (e.g. BAR, I-BAR proteins). In addition to in vitro experiments, our tests are also performed on cell cultures in order to obtain a complex picture of the mechanisms being investigated.

During their work, the students gain insight into the research work taking place at the institute and learn about the research methods required for actin research.

Myosins are motor proteins responsible for cell motility and intracellular transport by converting the chemical energy of ATP into mechanical work. A recently discovered motor protein family is myosin 16, which can be found mostly in developing neurons, but little is known about its proper function.

Our research aim is to understand the basic features of this protein which has a unique domain structure. To achive this, we produce recombinant protein fragments in bacterial and baculovirus expression system. The enzymatic properties of the proteins are examined with transient kinetic, spectroscopic and microscopic methods. We are searching for binding partners of myosin 16 in neuronal tissue (newborn rat brain), the interactions are characterised with surface plasmon resonance. The localization or migration of myosin 16 in live cells are visualized with fluorescence microscopy after microinjection.

You are welcome to join this diverse project at several points to find answers for exciting scientific problems, meanwhile getting familiar with the latest biomedical techniques.

Fluorescent microscopic image of Cos7 cells: a) transmission image; b) actin cytoskeleton lebelled with GFP; c) After microinjecting Myosin 16b labelled with Alexa568 localize into the nucleus