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Universität Wien (2021)

Exploring survival strategies of microorganisms in temperate and arid soils

Maritsch, Klara Nina

Titre : Exploring survival strategies of microorganisms in temperate and arid soils

Erforschung der Überlebensstrategien von Mikroorganismen in gemäßigten und ariden Böden

Auteur : Maritsch, Klara Nina

Université de soutenance : Universität Wien

Grade : Masterarbeit 2021

Résumé
Most soil microorganisms spend the majority of their time in a dormant (or non-growth) state to sustain in this challenging environment, as nutrients and water can be scarce for long periods. Although dormancy drastically reduces energy costs, a basal energy supply is still required for cell maintenance and survival. Yet, little is known about the mechanisms that enable dormant microorganisms to remain energized and persist in the soil for extended periods of time. It was the goal of this study to investigate survival strategies of microorganisms inhabiting temperate and arid soils using a culture- and omics-based approach. The ability to use atmospheric H2 as an energy source during periods of carbon starvation via the high-affinity group 1h [NiFe]-hydrogenase has recently been discovered in several soil bacteria including members of the (phylum) Acidobacteria, which are highly abundant in temperate soil. To investigate if acidobacteria harboring the H2 scavenging physiology have an advantage during periods of carbon limitation and resume growth after extended periods of dormancy without impairment as compared to acidobacteria without this physiology, starvation experiments were performed using pure cultures of two representative temperate soil strains. The viability of both strains was evaluated in exponential- and stationary-phase (i.e. proxy for starvation conditions) cells by assessing their metabolic activity via CTC staining and 15NH4Cl incubation. Under starvation conditions, the group 1h [NiFe]-hydrogenase containing strain had a higher metabolic activity and higher 15NH4Cl uptake indicating a higher protein synthesis than the control strain, suggesting an increased likelihood to survive periods of carbon starvation and persist in the soil.

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Page publiée le 5 mars 2023