DDX53 and colonic neoplasm: The ppGpp-null mutant (relA::kan, spot::cat) and the ppGpp-null mutant carrying the glmS mutation, which are both resistant to kanamycin and chloramphenicol, were transformed with ampicillin-resistant s.tglmS+ p. Mice carrying grafted CT26 (mouse colon cancer) cells were constructed as described previously.