Journal of Applied Mechanics Reviews and Reports
ISSN: 3069-0803 | DOI: 10.64030/3069-0803
Jamlet Monaselidze, Evgeni Kiziria, Maya Gorgoshidze, Eteri Gelagutashvili, Mikheil Gogebashvili, Giorgi Majagaladze and Eteri Ginturi
The study of optical absorbance and thermal denaturation spectra of Spirulina platensis, grown in a cesium-containing medium mixture and subjected to continuous γ-irradiation at a rate of 1.1 Gy/min for over one year (resulting in a total dose of 543 kGy), demonstrated the complete disappearance of both optical and thermal spectra. After 48 hours of recultivation in standard Zarrouk’s medium, the previously γ-irradiated, colorless suspension showed significant recovery of the phycobilisome complex (PBCc) structure, accompanied by minor changes in the denaturation profile and a decrease in denaturation enthalpy of about 15–20%. After 7 days of recultivation, both optical and differential calorimetry (DSC) studies demonstrated complete restoration of structure and functions of Spirulina platensis. Based on our previous data demonstrating full restoration of the structural organization and biological functions of microalgae previously irradiated with 400 kGy 137Cs, we suggest that the changes observed after 48 hours of recultivation are caused by the influence of cesium ions on DNA organization within the nucleoprotein complex, leading to alterations in protein synthesis in Spirulina platensis. The complete restoration of the PBCc structure by day 7 of recultivation likely results from the release of cesium ions into the solution due to the rapid growth of the microalgae in the recultivation process. The restoration of the PBCc complex after recultivation of previously treated and irradiated samples, as well as the nature of the highly cooperative transition of the biopolymer that melts at 77.5 °C and fully recovers after heating to 110 °C, are discussed.