Studies of unicellular microorganisms Saccharomyces cerevisiae by means of positron annihilation lifetime spectroscopy

• Published in: Nukleonika Vol. 60; no. 4; pp. 749 - 753
• Main Authors: Kubicz, Ewelina, Jasińska, Bożena, Zgardzińska, Bożena, Bednarski, Tomasz, Białas, Piotr, Czerwiński, Eryk, Gajos, Aleksander, Gorgol, Marek, Kamińska, Daria, Kapłon, Łukasz, Kochanowski, Andrzej, Korcyl, Grzegorz, Kowalski, Paweł, Kozik, Tomasz, Krzemień, Wojciech, Niedźwiecki, Szymon, Pałka, Marek, Raczyński, Lech, Rajfur, Zenon, Rudy, Zbigniew, Rundel, Oleksandr, Sharma, Neha Gupta, Silarski, Michał, Słomski, Artur, Strzelecki, Adam, Wieczorek, Anna, Wiślicki, Wojciech, Zieliński, Marcin, Moskal, Paweł
• Format: Journal Article
• Language: English
• Published: De Gruyter Open 01.12.2015; Sciendo
• Subjects: environmental scanning electron microscopy (ESEM); free volume; inverted microscopy; positron annihilation; positronium; yeasts
• ISSN: 0029-5922; 0029-5922
• DOI: 10.1515/nuka-2015-0135

Results of positron annihilation lifetime spectroscopy (PALS) and microscopic studies on simple microorganisms, brewing yeasts, are presented. Lifetime of -positronium ( -Ps) were found to change from 2.4 to 2.9 ns (longer-lived component) for lyophilized and aqueous yeasts, respectively. Also hygroscopicity of yeasts in time was examined, allowing to check how water – the main component of the cell – affects PALS parameters, thus lifetime of -Ps were found to change from 1.2 to 1.4 ns (shorter-lived component) for the dried yeasts. The time sufficient to hydrate the cells was found below 10 hours. In the presence of liquid water, an indication of reorganization of yeast in the molecular scale was observed. Microscopic images of the lyophilized, dried, and wet yeasts with best possible resolution were obtained using inverted microscopy (IM) and environmental scanning electron microscopy (ESEM) methods. As a result, visible changes to the surface of the cell me mbrane were observed in ESEM images.