Effects of Low-Level Deuterium Enrichment on Bacterial Growth

Abstract

Using very precise (±0.05%) measurements of the growth parameters for bacteria E. coli grown on minimal media, we aimed to determine the lowest deuterium concentration at which the adverse effects that are prominent at higher enrichments start to become noticeable. Such a threshold was found at 0.5% D, a surprisingly high value, while the ultralow deuterium concentrations (≤0.25% D) showed signs of the opposite trend. Bacterial adaptation for 400 generations in isotopically different environment confirmed preference for ultralow (≤0.25% D) enrichment. This effect appears to be similar to those described in sporadic but multiple earlier reports. Possible explanations include hormesis and isotopic resonance phenomena, with the latter explanation being favored.

Isotopic Resonance Hypothesis: Experimental Verification by Escherichia coli Growth Measurements

“…These results, combined with a wealth of literature starting from 1930s141519202122232425262728293031, including our recent studies on the effect of enriched deuterium on bacterial growth32, open a venue for scientific and industrial exploration of the isotopic resonance phenomenon in a whole range of fields. In astrobiology, the impact of the isotopic resonance phenomenon on the origin of life on Earth has to be seriously considered.…”

On the Effect of Planetary Stable Isotope Compositions on Growth and Survival of Terrestrial Organisms

“…Slightly higher deuterium content may not be toxic per se , but could instead lead to faster kinetics of most biochemical processes involving proteins (IsoRes theory predicts a strong resonance at ≈300 ppm D[31,32]), which in turn means shorter lifespan. This phenomenon is likely to be responsible for the shorter lifetime at 600 ppm, while at 1200 ppm the general toxicity of deuterium may become the prime reason for the lifespan decline.…”

“…coli was chosen, for which we have previously established a very accurate method of measuring the growth parameters[31]. Minimal media with only glucose as a source of carbon ideally suits for the modulation of isotopic abundances.…”

“…Thus any change in isotopic abundances should result in slower growth. However, recent experiments have shown that this is not necessarily the case[30,31]. …”

Merging in-solution X-ray and neutron scattering data allows fine structural analysis of membrane-protein detergent complexes

“…This is particularly relevant as deuterated media/detergents are often expensive and toxic for bacteria, leading to decreased protein yields. 23 Crucially, the multiphase analysis does not require information on the 3D structure of the protein, which opens the possibility to apply this methodology to a wide range of important membrane proteins that have so far remained inaccessible to high resolution structural analysis. Whilst SAS has become a popular technique amongst structural biologists, combinations of SANS, SAXS and MD has remained underexploited by the community.…”