Biological Influence of Deuterium on Prokaryotic and Eukaryotic cells

Abstract

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 k_H/k_D = 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.