**3.5 Long-term storage of guest BACs in** *B. subtilis* **endospores**

The BGM derived from *B. subtilis* is capable of forming spores reminiscent of plant seeds. Spores survive for a long time in unfavorable environments including aridity (Nicholson et al., 2000, 2002; Nicholson & Galeano, 2003; Takahashi et al., 1999; Benardini et al., 2003). *B. subtilis* spores readily start to germinate when moved back into nutrition-rich broth and start to grow immediately. We examined the stability of DNA inside spores (Kaneko et al., 2005) and found that the spores are stable for year at room temperature without requiring special devices. BGM spores may not be of value for use with small DNA that is synthesized and prepared routinely. However, as the size of the guest DNA increases, these spores should become more valuable. BGM spores should provide a low-cost, long-term reservoir for guest DNAs.
