Fig. 1.

SFB status of mice housed in different animal facilities. (A) Variable SFB colonization of different strains at the different sites. PCR-determined relative SFB levels in mice housed at TAC, JAX, or the NRB facility. Each bar represents the average level +/− SEM for six mice (three males and three females). Fecal pellets taken from mice that were shipped to the NRB facility from TAC or JAX were collected and processed or were frozen within 24 h of arrival. Mice were 5–6 wk of age at the time of feces collection. SFB negativity in the NOD strain was confirmed 10 months later with additional sets of mice at 6–8 wk of age. (B) SFB colonization through four generations of NOD mice housed at the NRB facility. Squares represent males; circles indicate females. Black symbols indicate SFB-positive mice; white symbols indicate SFB-negative mice; mixed black/white symbols indicate mice of unknown SFB status. Each litter is delineated by the brackets below, with the date of birth (month/day) within 2010 indicated. SFB status of pups was assessed by PCR of fecal DNA at 4–6 wk of age except for breeding cages A–J. Parental feces were collected and examined for the presence of SFB within 2–3 wk of the litter encompassing the line of descent. The parental age at the time of feces collection varied between 2.5 and 6 mo.