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Investigation of cellular metabolic activity with stable-isotope probing (SIP) implies the admittance of an isotope tracer into the metabolic pathway. Incubation with several isotope-markers (multi-isotope tracing) is required to trace nutrient metabolization and elucidate inter-cellular interactions in complex hosts and environmental communities. To cope with the lability of cell nutrition, deuterium in heavy 2 H 2 16 O water is employed as a substrate-independent general tracer of metabolic activity. However, the spatially-resolved deuterium tracing is hampered by detection limits due to its relatively low ionization yield and mass-interference issues. In the present work, we comprehensively assess the quantitation of deuterium incorporation into biomass employing the outstanding capabilities of nanoscale Secondary Ion Mass Spectrometry facilitating quantitative analysis of metabolic activity with single-cell or subcellular resolution. The effect of ion-probe-induced material relocation on the acquired pattern in 2 H enrichment has been considered. Analytical expressions are suggested for the restoration of the deuterium fraction from the unresolved C 2 2 H–C 2 1 H 2 mass-interference. Application of the suggested principle of equal relative assimilation and the multi-isotope tracing with the 2 H-marker on a phototrophic symbiotic consortium paves the way to sensing the metabolic interplay among cells, recognition of homeostatic and shifted nutrition, checking for completeness of isotope-labelling and elucidation of nonlabelled substrate contribution.

Microbial destruction of organochlorine pollutants is the one of the most effective approaches, the safest and promising methods for remediation the environment from pollution. This study presents strains of microorganisms that destroy hexachlorocyclohexane: Stenotrophomonas maltophilia IMV B-7288, Pseudomonas putida IMV B-7289 and Bacillus megaterium IMV B-7287—newly selected destructors of organochlorine pesticide hexachlorocyclohexane. Their advantages and features are considered, namely—exclusively of natural origin—microorganisms are isolated from places of total pollution. The studied strains are characterized by high resistance to the HCH contaminant (in the range of 100–1000 mg/l) and the ability to decompose in soil and liquid medium. We have found that strains B. megaterium IMV B-7287 and P. putida IMV B-7289 showed a high efficiency of destruction of HCH in laboratory studies when cultivated on a chlorine-free MM medium at 70.4–89.3% from initial content. For S. maltophilia IMV B-7288 has been found that the ability to degrade HCH-isomers depends on the season a little and it was at maximum in the summer for every studied HCH-isomer: 61.6–82.1% from initial amount. The investigated strains are promising for further work to create microbial compositions with the aim to provide an effictive destruction of HCH-isomers complex.