Raffinose

Yeast strain W303α was obtained from the Amon Lab at MIT. Synthetically defined dropout media (SD) was made by combing 1.7 g/L yeast nitrogen base without amino acid and ammonium sulfate (YNB) (Fischer), 5 g/L ammonium sulfate (Sigma), 0.6 g CSM-HIS-LEU-TRP-URA powder (MPBio), 20 g/L glucose (Sigma), and 10 mL/L of 100× adenine hemisulfate stock (1 g/L) (Sigma). 100× stocks of His (5 g/L), Leu (10 g/L), Trp (10 g/L), and Ura (2 g/L) (Sigma) were made in ddH₂O and filtered sterilized before supplementing cultures. Alternatively, complete synthetically defined media (CSM) was made with the above ingredients but with 0.79 g/L CSM mix (MPBio). YPD was made with 20 g/L peptone, 20 g/L glucose and 10 g/L yeast extract. CSM/SD-R media was made by replacing 20 g/L glucose with raffinose (VWR). CSM/SD-G media was made by replacing 20 g/L glucose with 20 g/L galactose and 20 g/L raffinose. Solutions were stirred and filter sterilized through a 0.22 μm filter top (EMD). Agar plates were made by adding 20 g/L BactoAgar (Fisher) and autoclaving before pouring.

All chemicals were purchased from Sigma-Aldrich Corporation (St. Louis, MO). Thioglycolate medium, peptones, yeast extract, raffinose and agar were purchased from VWR (West Chester, PA). C. perfringens strains JGS1936, JGS1473, JGS1882, JGS1521, JGS4104, JGS4151, and JGS4064 (Barbara et al., 2008 (link)) were a generous gift from Prof. J. Glenn Songer (Iowa State University, Ames, IA). These strains were selected since they were obtained from a wide variety of mammalian and avian hosts. The identities of selected C. perfringens spore preparations were confirmed by litmus milk test (Erickson and Deibel, 1978 (link)) and sequencing of the complete 16S rRNA gene.