Agarose gel electrophoresis of EcoRI-digested plasmid DNAs isolated from Alteromonas spp. and E. coli strains. Lanes: A, A28; B, A29; C, A28(pASS1); D, E. coli MV1184(pASS1); E, A28(pASS3.4); F, E. coli MV1184(pASS3.4); G, A28(pASS3.42); H, E. coli MV1184(pASS3.42); M, HindIII-digested phage lambda DNA.