Spaceflight Shifts in Community rRNA Copy Number in the Salivary Microbiome of Astronauts

Abstract

The oral microbiome is stable, easily sampled, and can indicate disease. Using metagenomic data from GeneLab, I examined the effects of spaceflight on the human salivary microbiome using a composite community measure, average rRNA copy number. A higher copy number is associated with a faster growth rate and primary microbial succession. I found a significant increase in community weighted mean copy number between pre-spaceflight and during-spaceflight samples (p=0.0082). Furthermore, changes in abundance suggest a greater impact on individual species rather than phyla-level changes. Finally, a robustness analysis highlighted the importance of accurate copy number estimates and species-level identification.Graphical Abstract