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International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
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T2: O–8
Impact of transcranial electric stimulation on molecular and elemental
components in the brains of rats addicted to high-caloric nutrients – the
study by infrared and synchrotron X-ray imaging spectroscopies
Agata Ziomber
1
, Artur D. Surówka
2
, Mateusz Czyżycki
2,3
, Alessandro Migliori
3
,
Magdalena Szczerbowska-Boruchowska
2
1
Chair of Pathophysiology, Faculty of Medicine, Jagiellonian University Medical College, Czysta 18,
31-121 Krakow, Poland
2
Faculty of Physics and Applied Computer Science, AGH University of Science and Technology,
al. A. Mickiewicza 30, 30-059 Krakow, Poland, email: asurowka@agh.edu.pl
3
International Atomic Energy Agency (IAEA), Vienna, Austria and ELETTRA Sincrotrone Trieste,
Basovizza, Italy
A high-caloric diet is now considered as one of the most significant risk factors for
developing serious lifestyle cardiovascular and neurological diseases. It is surmised that
overnutrition may overbalance the electric activity in the brain areas triggering appetite and
craving, gradually leading to food addiction and finally obesity [1]. In order to understand the
impact of the high-caloric diet on brain activity, the interplay between changes in molecular
components and metal ions must be studied in the brain areas particularly affected by food
addiction [2]. In our study, we aimed at showing, whether or not, impacting the brain electric
activity by transcranial direct current brain stimulation (tDCS) has any behavioral and
biochemical effects on lipid, protein secondary structure and levels of metal ions [3]. For doing
so, thin brain tissue sections were taken from electrically- and sham-stimulated rats on a high-
caloric diet. The samples were raster-scanned with current state-of-the-art modern molecular and
elemental micro-imaging modalities: Fourier transform infrared and vacuum-based synchrotron
X-ray fluorescence (ELETTRA synchrotron facility in Trieste, Italy) spectroscopies. The
contribution will aim at outlining the details of our unique brain stimulation procedure, and
comparing the most striking molecular and elemental changes invoked in the appetite-triggering
brain areas of obese rats. It will be demonstrated that the clinical efficacy of anodal-type tDCS
has a stronger impact on the brain by altering the surface masses of the metal ions such as Na
+
,
K
+
, and Cl
–
. Perturbation in major molecular components will be shown to correlate with metal
ions. The study, although preliminary, demonstrates that by stimulating the brains of rats
addicted to high-caloric diet, the feeding behavior can be significantly changed, resulting in
decreased appetite and craving. Therefore, our brain stimulation method paves the way for the
novel treatments for challenging the most common metabolic syndromes causing overnutrition
and obesity.
Keywords: brain stimulation, obesity, Fourier transform infrared spectroscopy, synchrotron X-ray fluorescence
Acknowledgments
This work was supported by the National Science Centre Poland, grant number DEC-
2013/09/B/NZ4/02539. We would also thank ELETTRA Sincrotrone Trieste (Italy) for beamtime provision.
References
[1] N. Hariri, L., Thibault, Nutr. Res. Rev. 23 (2010) 270.
[2] S.J. Brooks, et al., PLoS One. 8 (2013) e60393.
[3] D. Liebetanz, et al. Epilepsia. 47 (2006) 1216.
XIV
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International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
77
T2: O–9
Spectral demonstration of structural transitions in albumins
Svetlana Tankovskaia
1
, Karina Abrosimova
1
, and Sofia Paston
1
1
Department of Molecular Biophysics and Polymer Physics, Faculty of Physics, Saint-Petersburg
State University, Ulyanovskaya, 3, St.Petersburg 198504, e-mail: Russia.tasva-ara1@yandex.ru
Proteins functions are determined by their structure. Environmental conditions, chain
modifications, interaction with co-factors and ligands caused changes in proteins structure and
activity. The development of new approaches to experimental analysis of protein structure and
dynamics continues incessantly. In the present study the different spectral techniques (FTIR, UV
and fluorescent spectroscopy) and zeta potential measurements are used to reveal structural
transitions in human serum albumin (HSA) and ovalbumin (OVA) during the changes in pH,
and also electrolyte and aliphatic alcohols content in solution.
IR spectroscopy is a very sensitive method for proteins secondary structure analysis. To
determine the percentage of α-helix, β-sheets, β-turns, random regions and intermolecular
bindings in HSA and OVA we applied the decomposition of Amid I band (1700–1600 cm
–1
) in
the proteins IR spectra [1]. Spatial organization of protein globule affects the distance between
amino acid residues and their accessibility for the solvent. Both these factors manifest in
electronic absorption and fluorescent spectra of the protein. Protonation and deprotonation of
amino acids side groups at pH variation lead to “native state – molten globule” transition of the
protein, when chromophores Tyr and Trp become available for contact with the solvent, that
shifts protein absorption and emission spectra. Comparing the results of titration curves, spectral
parameters, zeta potential and secondary structure data enable the researcher understand what
kind of structural changes take place in different conditions. Native states of studied albumins
occur in the vicinity of their isoelectric point and distinguish maximum content of α-helices and
partial aggregation of protein molecules. In the presence of electrolyte (NaCl) the aggregation
decreases. Aliphatic alcohols destabilize the native state of albumins.
Keywords: albumins; FTIR spectroscopy; UV spectroscopy; fluorescence; zeta potential
Acknowledgment
A part of this work was performed using the equipment of the Centre for Optical and Laser Materials
Research (COLMR), St. Petersburg State University.
This work was supported by the RFBR, project no. 15-08-06876 and SPbSU (11.37.290.2015).
References
[1] J. Kong, Sh. Yu, Acta Biochimica et Biophysica Sinica 39 (2007) 549.
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