Thomas Pribasnig gives a short talk at the 1st Annual VDSEE Symposium:

"The biofilm lifestyle of ammonia-oxidizing archaea"

16 February 2024

Lecture Hall 1, UBB, University of Vienna

The biofilm lifestyle of ammonia oxidizing archaea: An understudied mode of growth and activity

Thomas Pribasnig, Maximilian Dreer, Logan Hodgskiss, Melina Kerou and Christa Schleper

Ammonia-oxidizing archaea (AOA) are ubiquitously distributed in soil and aquatic environments and through their autotrophic growth contribute significantly to both the global nitrogen and carbon cycles. Although, there is a continuously increasing number of axenic isolates available, comparably little is known about ecophysiological aspects and growth modes of AOA. In this study, Nitrososphaera viennensis was grown as a continuous culture in a bioreactor, where biofilm formation was observed under high flow rates. In order to better characterize growth in biofilm compared to planktonic growth, we performed a transcriptome study based on RNA-seq and were able to identify significantly distinct expression patterns between both growth modes, including (among others) genes for EPS production and adhesion being highly expressed in the biofilm. We then expanded our investigations to four strains of AOA representing different families (Nitrososphaeraceae and Nitrosopumilaceae) and ecosystems (terrestrial and marine) to explore how widespread the ability to form biofilms is amongst the diversity of AOA. While these strains showed differing ability to form biofilms, soil strains exhibited strongest biofilm formation. Our comparative analyses involving scanning electron microscopy (SEM), staining of biofilm extra-polysaccharides and transcriptional analysis during growth in a biofilm, reveals distinct biofilm-forming abilities of AOA strains reflecting their phylogenetic distribution and ecological niches.