Screening and characterization of marine bacteria with antibacterial and cytotoxic activities, and existence of PKS I and NRPS genes in bioactive strains]

Antibacterial and cytotoxic activities were screened for marine bacteria which have been isolated from organism, sediments and seawater in China coastal area. The results showed that 42 isolates had antimicrobial activity and 12 isolates had cytotoxicity. Molecular phylogenetic analysis of marine bacteria with cytotoxicity based on 16S rRNA sequences indicated that they were belong to the genera Aerococcus, Agrobacterium, Alteromona, Bacillus, Exiguobacterium, Paracoccus, Pseudoalteromons, Rheinheimera. Furthermore, marine bacteria with cytotoxicity were also screened for PKS I and NRPS genes which could be responsible for bioactive secondary metabolites biosynthesis, 4 strains having KS domain or A domain were obtained, which provide strong evidence that marine bioactive bacteria can produce natural products through PKS and NRPS pathways.