 comparison ultraviolet sensit bacillu subtili bacteriophag spo2 infecti dna deoxyribonucl acid extract clear plaqu mutant temper phage spo2 infecti incub compet cultur bacillu subtili 168 relationship number infecti center dna concentr linear sensit infecti dna ultraviolet light greater free phage subtili 168 host acriflavin inhibit host cell reactiv increas rate ultraviolet inactiv free phage approach inactiv rate phage dna acriflavin surviv curv infecti dna non-host reactiv mutant hcr subtili 168 isol surviv curv spo2 phage steeper hcr mutant host hcr parent strain host ultraviolet sensit phage dna greater free phage subtili hcr host differ sensit differ subtili hcr host explan greater ultraviolet sensit infecti dna discuss 