FIG 3.
Chitinase activities of wild-type and mutant cells. Chitinase activities of spent media, intact cells, and cell extracts were determined using the synthetic substrates 4-MU-(GlcNAc)2, and 4-MU-(GlcNAc)3. Equal amounts of each sample, based on the protein content of the cell suspension, were incubated with 10 nmol of synthetic substrate for 30 min at 37°C, and the amount of 4-MU released was determined by measuring fluorescence emission at 460 nm following excitation at 360 nm. Yellow, wild-type F. johnsoniae UW101. Red, chiA mutant CJ1808. Green, CJ1808 with pSSK05, which carries chiA. Tan, gldNO deletion mutant CJ1631A. Purple, CJ2325, which produces ChiA lacking the C-terminal 106 amino acids. Blue, Fjoh_4175 deletion mutant CJ2355.