Project description:We report how high and low linear energy transfer (LET) radiation, microgravity, and elevated dietary iron affect colon microbiota (determined by 16S rDNA pyrosequencing) and colon function. Three independent experiments were conducted: 1) fractionated low LET γ radiation (137Cs, 3 Gy, RAD), high Fe diet (IRON) (650 mg/kg diet), and a combination of low LET γ 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. Low LET radiation, high Fe diet, and spaceflight did not significantly affect diversity or richness, or elevate pathogenic genera. Spaceflight increased Clostridiales and decreased Lactobacillales, and similar trends were observed in the experiment using a ground-based model of microgravity, suggesting altered gravity may affect colonic microbiota. Microbiota characteriztion in these models is a first step in understanding the impact of the space environment on intestinal health. Overall design: Phylogenetic characterizaiton of fecal microbiota from a total of 49 mouse and rat fecal samples (18 and 31 samples, respectively, no replicates)
Project description:We found that mainstream cigarette smoking (4 cigarettes/day, 5 days/week for 2 weeks using Kentucky Research Cigarettes 3R4F) resulted in >20% decrease in the percentage of normal Paneth cell population in Atg16l1 T300A mice but showed minimal effect in wildtype littermate control mice, indicating that Atg16l1 T300A polymorphism confers sensitivity to cigarette smoking-induced Paneth cell damage. We performed 16S rRNA sequencing to identify potential microbiota changes associated with Paneth cell defect in Atg16l1 T300A mice exposed to cigarette smoking. Female mice were used at 4-5 weeks of age. Cigarette smoking was performed using smoking chamber with the dosage and schedule as described above. The fecal samples from the mice were collected for 16S rRNA sequencing analysis after completing 6 weeks of smoking.