chiA is required for chitin utilization. (A) Approximately 106 cells of wild-type F. johnsoniae UW101, chiA mutant CJ1808, and CJ1808 with pSSK05, which carries chiA, were spotted on MYA-chitin medium and incubated at 25°C for 2.5 days. (B) Wild-type F. johnsoniae CJ1827, chiA mutant CJ1808, and Fjoh_4175 deletion mutant CJ2355 were spotted on MYA-chitin medium and incubated at 25°C for 2.5 days.