Space environmental factor impacts upon murine colon microbiota and mucosal homeostasis

Three independent experiments were conducted: 1) fractionated low LET gamma radiation (137Cs, 3 Gy, RAD), high Fe diet (IRON) (650 mg/kg diet), and a combination of low LET gamma radiation and high Fe diet (IRON+RAD) in male Sprague-Dawley rats; 2) high LET 38Si particle exposure (0.050 Gy), 1/6 G partial weight bearing (PWB), and a combination of high LET38Si particle exposure and PWB in female BalbC/ByJ mice; and 3) 13 d spaceflight in female C57BL/6 mice.

For each experiment, the colon was resected and feces removed for microbial sequencing analysis on a Roche 454 Genome Sequencer FLX Titanium instrument (Microbiome Core Facility, Chapel Hill NC) using the GS FLX Titanium XLR70 sequencing reagents and protocols. Analysis of amplicon sequencing data was carried out using the QIIME pipeline. Low LET radiation, high iron diet, and spaceflight increased Bacteroidetes and decreased Firmicutes.