Archives of Microbiology

, Volume 144, Issue 3, pp 286–290

Influence of very low doses of ionizing radiation on Synechococcus lividus metabolism during the initial growth phase

  • Annie Conter
  • Dominique Dupouy
  • Christine Delteil
  • Hubert Planel
Original Papers

DOI: 10.1007/BF00410964

Cite this article as:
Conter, A., Dupouy, D., Delteil, C. et al. Arch. Microbiol. (1986) 144: 286. doi:10.1007/BF00410964

Abstract

Previous results from this laboratory have shown that very low chronic doses of gamma radiation can stimulate proliferation of the Cyanobacterium Synechococcus lividus. This modification of cell proliferation occurred during the first doubling. In this paper, we have compared the metabolism of cells cultivated in a normal environment or under chronic irradiation. Incubation of the cells in a new medium induced a high superoxide dismutase (EC 1.15.1.1, SOD) activity at the 18th hour and a degradation of phycocyanin, thus demonstrating that cells were submitted to a photooxidative stress. This increase in superoxide dismutase activity was followed by concomittant peaks of glutathione reductase (EC 1.6.4.2, GR) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49, G6P-DH) at the 24th hour. Irradiated cultures at a dose of 53.5 mGray/year show an earlier and higher peak of SOD, GR, and G6P-DH. In a second stage, cultures showed an earlier onset of photosynthesis under irradiation, as evidenced by an increase in pigment content and an enhancement of glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.13, GAP-DH). These results show that the radiostimulation is related to the activation of enzymes protecting against peroxides that were induced under oxidative circumstances and to the activation of a glucose catabolism via the oxidative pentose phosphate pathway.

Key words

Synechococcus lividusCyanobacteriumGamma irradiationPhotooxidative stressSuperoxide dismutaseGlutathione reductaseGlyceraldehyde-3-P dehydrogenaseGlucose-6-P dehydrogenase

Abbreviations

mGy

milli-Gray

SOD

superoxide dismutase

G6P-DH

glucose-6-phosphate dehydrogenase

GAP-DH

glycer-aldehyde-3-phosphate dehydrogenase

GSSG

oxidized glutathione

Copyright information

© Springer-Verlag 1986

Authors and Affiliations

  • Annie Conter
    • 1
  • Dominique Dupouy
    • 1
  • Christine Delteil
    • 1
  • Hubert Planel
    • 1
  1. 1.Laboratoire de Biologie MédicaleFaculté de Médecine Toulouse-PurpanToulouseFrance