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Identifier

000401709

Title

Μελέτη γήρανσης σε μύες in-vivo, μέσω μικροσκοπίας Γένεσης Δεύτερης Αρμονικής ευαίσθητης στην Πόλωση

Alternative Title

Study of aging in muscles in-vivo, using Polarization sensitive Second Harmonic Generation microscopy

Author

Τσαφάς, Βασίλης Α.

Thesis advisor

Φωτάκης, Κώστας

Reviewer

Ταβερναράκης, Νεκτάριος
Λουκάκος, Παναγιώτης

Scientific advisor

Φιλιππίδης, Γιώργος
Ψιλοδημητρακόπουλος, Σωτήριος

Abstract

The need to understand basic biological mechanisms, such as aging, requires the observation of living organisms at cellular level, therefore high resolution imaging microscopy is required. In parallel, the form of microscopy to be used needs to be as minimally invasive as possible, in order for the observation to be carried out in-vivo. Furthermore, it is of great challenge to derive quantitative biological information, in order to eliminate the nowadays qualitative analysis, based i.e. on the experienced eye of an expert. A possible solution to the above could be the optical Polarization sensitive Second Harmonic Generation (PSHG) imaging microscopy. Second Harmonic Generation (SHG) is a non-linear scattering phenomenon (no energy deposition in to the sample) which makes this method minimally invasive with very high resolution (approximately 0.5 μm) giving us the ability for in-vivo observation of biological samples at cellular level. In addition, this method is dependant to polarization which gives the ability for quantitative information at molecular level. In this study we investigated for the first time how aging affects the myosin molecules in Caenorhabditis elegans (C. elegans) striated muscles using polarization sensitive second harmonic generation (PSHG) microscopy. There are two ways to derive quantitative information in molecular level from PSHG data. The first is by using an iterative fitting procedure, while the second and much faster is by using the analytical FFT (Fast Fourier Transform). It is worthwhile to note that in this study a new filtering technique has been utilized for the first time for the FFT based PSHG data analysis, which significantly increases FFT robustness and accuracy. Our results, after utilizing this filtering technique, show significant changes in myosin structure between young (1 day) and old (9 days) C. elegans. Specifically, we found that the myosin SHG angle decreases upon aging. Our results encourage further experiments e.g. in mutated C. elegans samples, towards the investigation of the exact mechanism of aging in the myosin molecule. The long-term scope of this work is to develop a fast and precise high-resolution optical diagnostic tool, able to quantitatively characterize tissue pathologies in-vivo.

Language

Greek

Subject

C. elegans

Fast fourier transform (FFT)

Fitting

Μη-γραμμική μικροσκοπία

Προσαρμογή καμπύλης

Issue date

2016-07-22

Collection

School/Department--School of Sciences and Engineering--Department of Physics--Post-graduate theses