16S RNA gene amplified from DNA isolated from cultures. Separation of PCR products amplified with bacteria specific 16S rRNA primers in 6% polyacrylamide gels with 0–100% denaturing gradient. Panels A and B. 16S RNA gene amplified from DNA isolated from 24 cultures. The number above each lane indicates the culture name and the number in parenthesis represents depth of isolation in meters. Lanes M are the ladders: M1= Aquimarina muelleri, M2= Escherichia coli, M3= Sulfurimonas denitrificans, M4= Vibrio alginolyticus and M5= Mycobacterium smegmatis. The sequenced bands are identified by number.