Απομόνωση, κλωνοποίηση, υπερπαραγωγή, βιοχημικός και βιοφυσικός χαρακτηρισμός ενός χιτινολυτικού ενζύμου από το ψυχρόφιλο βακτήριο Moritella marina

• Main Authors: Stefanidi, Eleni, Στεφανίδη, Ελένη
• Format: Doctoral or Postdoctoral Thesis
• Language: Greek
• Published: National and Kapodistrian University of Athens 2008
• Subjects: Ψυχρόφιλα βακτήρια; Προσαρμοσμένα σε χαμηλές θερμοκρασίες ένζυμα; Χιτινολυτικά ένζυμα; Κλωνοποίηση γονιδίων; Έκφραση γονιδίων; Καθαρισμός; Βιοχημικός χαρακτηρισμός; Προτυποποίηση βάσει ομολογίας; Psychrophilic bacteria; Cold-adapted enzymes; Chitinases; Gene cloning; Gene expression; Prolification; Biochemical characterization; Homology modeling; Φυσικές Επιστήμες; Βιολογία; Natural Sciences; Biological Sciences; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/10442/hedi/20898; https://doi.org/10.12681/eadd/20898

Chitin, a carbohydrate polymer composed of alternating beta-1,4-linked N-acetylgiucosamine residues, is the second most abundant organic compound in nature. In the aquatic biosphere alone, it is estimated, that more than 10¹¹ tons of chitin are produced annually. Although the deep-sea marine environment is characterized by high hydrostatic pressures and low temperatures, there seems to be a highly active microbial community that is able to decompose chitin. Consequently, the chitinases, produced from the bacteria above, and are responsible for the degradation of the chitin, should have high catalytic activities under these low temperature conditions compared with those of mesophilic and thermophilic species. Psychrophiles are the organisms that live under low temperatures conditions, very often close to 0°C. These organisms live in Antarctica, in the cold oceans, and icebergs, and also on the mountains. They contain many prokaryotic and eukaryotic species, like fungi, seaweed, even archaea. In the context of her PhD thesis, executed at the Laboratory of Biochemistry, Department of Biology, University of Athens, Eleni Stefanidi undertook the isolation of a new chitinase gene, overproduction, biochemical and biophysical study of the recombinant enzyme from the psychrophilic and marine bacterium Moritella marina. Till today, it is the fifth psychrophilic chitinase that has been isolated and one of the four that has been studied inclusively. At the initial stage of the experimental part, a series of factors affecting the growth rate of the culture and the induction of the chitinolytic activity of this psychrophilic bacterium, such as the type of chitin used and the conditions of the bacterial culture, were elucidated. M. marina was cultivated at 15°C in two major types of complex medium: the minimal, inducing medium, containing chitin, as the sole carbon, nitrogen, and energy source, and the rich, non-inducing medium, where chitin was replaced by a variety of nutrient, non-chitinous substrates. The above ...