Biological Influence of Deuterium on Prokaryotic and Eukaryotic cells

Biologic influence of deuterium (D) on cells of various taxonomic groups of prokaryotic and eukaryotic microorganisms realizing methylotrophic, chemoheterotrophic, photo-organotrophic, and photosynthetic ways of assimilation of carbon substrates was investigated at cellular growth on media with maximal content of heavy water (D2?). For this aim the method of step by step adaptation technique of cells to D2? was developed, consisting in plating of cells on 2 % (w/v) agarose nutrient media containing increasing gradient of concentration of D2? (from 0 up to 98 % (v/v) D2O) and the subsequent selection of stable to D2O cells. Cells grown on media with a low gradient of D2? concentration were consequently transferred onto media with higher gradient of D2?, up to 98 % (v/v) D2?. In the result of that technique were isolated individual cell colonies representing the progeny of a single cell resistant to the action of D2O, biological material of which instead of hydrogen contained deuterium with high levels of deuterium enrichment ~92.0–97.5 atom.% D. Our studies demonstrated that the effects observed at the cellular growth on D2O possess a complex multifactor character connected to changes of cytological, morphological and physiological parameters – cellular size, non-uniform distribution of DNA, magnitude of the lag-period, time of cellular generation, outputs of biomass, a ratio of amino acids, protein, carbohydrates and fatty acids synthesized in D2O, and with an evolutionary level of organization of investigated object. The maximum kinetic isotopic effect observed at 22 0C in biochemical reactions leading to rupture of bonds involving H and D atoms lies in the range kH/kD = 5–7 for C–H versus C–D, N–D versus N–D, and O–H versus O–D-bonds. Keywords: bacteria; blue-green algae, deuterium; heavy water; isotopic effects, IR-spectroscopy