Document 
Free access article
DOI: 10.1051/epjap:1999116
Eur. Phys. J. AP 5, 101-109
Yeast cell metabolism investigated by CO2 production and soft X-ray irradiation
A. Masini1,5 - D. Batani1,5 - F. Previdi2,5 - M. Milani3,5 - A. Pozzi1 - E. Turcu4 - S. Huntington4 - H. Takeyasu4
1 Dipartimento di Fisica, Seconda Università di Milano Bicocca, via Emanueli 15, 20126
Milano, Italy
2 Dipartimento di Elettronica e Informazione, Politecnico di Milano, via
Ponzio 34/5, 20133 Milano, Italy
3 Dipartimento di Scienza dei Materiali, Seconda Università di Milano Bicocca, via
Emanueli 15, 20126 Milano, Italy
4 Rutherford Appleton Laboratory, Chilton Didcot, Oxon, OX11 OQX, UK
5 INFM, Istituto Nazionale di Fisica della Materia, Milano, Italy
previdi@elet.polimi.it
Received: 17 June 1998 / Accepted: 24 September 1998
Abstract
Results obtained using a new technique for studying cell metabolism are
presented. The technique, consisting in CO2 production monitoring, has been applied
to Saccharomyces cerevisiae yeast cells. Also the cells were irradiated using the
soft X-ray laser-plasma source at Rutherford Appleton Laboratory with the aim of
producing a damage of metabolic processes at the wall level, responsible for
fermentation, without great interference with respiration, taking place in
mitochondria, and DNA activity. The source was calibrated with PIN diodes and X-ray
spectrometers and used Teflon stripes as target, emitting X-rays at about 0.9 keV, with
a very low penetration in biological material. X-ray doses delivered to the different
cell compartments were calculated following a Lambert-Bouguet-Beer law. Immediately
after irradiation, the damage to metabolic activity was measured again by monitoring
CO2 production. Results showed a general reduction in gas production by irradiated
samples, together with non-linear and non-monotone response to dose. There was also
evidence of oscillations in cell metabolic activity and of X-ray induced changes in
oscillation frequency.
PACS
87.22.-q Physics of cellular and physiological processes -
87.50.-a Biological effects of electromagnetic and particle radiation -
52.40.Nk Laser-plasma interaction
Copyright EDP Sciences