Microcrystalline inclusions of biogenic guanine in algae: presence, properties and functions

Author: Mgr. Maxim Bokov
Supervisor: Doc. RNDr. Peter Mojzeš, CSc.
Type: Doctoral

Annotation: Guanine is an important biomolecule with many functions. As one of the purine bases, it represents the essential component of the genetic code of nucleic acid. The guanine-rich sequences of nucleic acids form four-stranded quadruplex structures that have been shown to have specific regulatory functions in gene expression and in the management of cell life cycle. In the form of guanosine triphosphate (GTP), along with ATP, it is involved in numerous processes of energy conversion. Other guanine derivatives (e.g., c-di-GMP, (p)ppGpp) are known to be important signaling and regulatory molecules of bacteria and plants. In many organisms, the ordered structures of biogenic crystalline guanine fulfill the role of photonic crystals for active light manipulating, coloration, and vision. Recently, crystalline guanine has been identified in microalgae where it is likely to serve as a store of nitrogen. However, it is possible that crystalline guanine has also other functions related to light manipulation or energy processes. For elucidation of these functions, simple and rapid method of identification and quantification of crystalline guanine directly within living cells during the cell cycle is needed. Confocal Raman microscopy is currently the only known method for reliable and unambiguous identification of crystalline guanine within cells. Moreover, this method is fast and does not require complicated sample preparation, therefore it is suitable for studying the conditions and dynamics of crystalline guanine formation. The subject of the dissertation will be a comprehensive study of the presence, properties and role of biogenic crystalline guanine in microalgae. The basic method will be confocal Raman microscopy, but other possibilities of optical or spectroscopic detection of crystalline guanine generated inside cells will be studied as well. Basic experimental equipment and methodology are available. Applicant is expected to possess knowledge at the level of completed MSc. degree in biophysics, chemical physics, biochemistry or biology, but in particular an initiative and independent approach.