Temporal enrichment of bacterial monoamine oxidase gene aboard the international space station and neuromodulator impacts of dopamine-driven ammonium formed by space isolate Leifsonia virtsii on Caenorhabditis elegans
Year: 2026
Type: article
Abstract: Dopamine regulates neurological functions, whereas its deficiency is linked with cognitive impairment and neurodegenerative diseases. The spatiotemporal distribution of dopamine-degrading microbes and the implications of dopamine catabolites on eukaryotes remain unexplored. Here, we demonstrate dopamine metabolism in Leifsonia virtsii F6_8S_P_1A T , an Actinomycetes isolated from the crew quarters aboard the International Space Station (ISS), and reveal dopamine catabolite-driven modulation of cognition and chemotaxis in Caenorhabditis elegans . L. virtsii shared a high 16S rRNA gene sequence similarity (>97.9%) and OrthoANI values (79.44–84.96%) with the Leifsonia species, isolated from terrestrial and aquatic habitats. A key gene encoding monoamine oxidase (MAO) involved in dopamine catabolism was found in 61.5% of validly established Leifsonia species, including L. virtsii , but not in ISS co-isolate L. williamsii F6_8S_P_1B T . Analysis of the ISS metagenome revealed temporal enrichment of MAO-associated signatures across Microbial Tracking studies (MT1 to MT3, 2015-2022), driven predominantly by candidate MAO homologs taxonomically associated with Actinomycetota in MT3, whereas strong F6-8S-P-1A-like MAO signals were restricted to two MT2 libraries. Dopamine input stimulated MAO gene expression in L. virtsii at early growth phase, and was found to complement cell division, biofilm establishment and extracellular NH 4 + formation in L. virtsii . MAO expression decreased with increasing time/NH 4 + concentration, whereas expression of marker genes representing DNA synthesis and transcription ( gyrB ), translation ( tuf ) and biofilm formation ( cslA ) exhibited concurrent upregulation. Dopamine-driven NH 4 + formation further altered cognition and chemotaxis in C. elegans . Our analysis suggests that the dopamine metabolic pathway detected in L. virtsii is not an ISS-specific trait and rather represents a phenotype retrieved from Earth. The present study provides direct evidence of spatiotemporal flexibility and heterogeneous dopamine-metabolizing capacity among Actinomycetes. The findings further demonstrate that a dopamine catabolite can modulate chemosensory interactions in a eukaryotic model and highlight the succession and persistence of MAO-bearing taxa aboard ISS.
Source: Frontiers in Microbiology
Language: English
Subfield: Physiology (medical)
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,801
OpenAlex ID: W7223353445