Fig. 2

Beta diversity of the salivary microbiome. Non-metric multidimensional scaling (NMDS) ordination of the salivary microbiome collected from ten astronauts collected pre-flight, in-flight (i.e., on the ISS), and post-flight. Each dot on the graph represents a sample, with the different colors representing a subject, and the different shapes representing a flight status. The closer the dots are to each other on the graph, the more similar the samples are in microbiome composition. The plots represent ASV sequences summarized, based on taxonomy, to the genus level and then clr transformed. No distinct clusters were observed, indicating no overall microbiome difference between subjects and based on flight status. The same analysis was performed at the ASV level and showed the same trends as at the genus level. The data used for analysis was clr transformed and Euclidean distances used.