Identification of bacterial species by 16S rDNA sequences
To identify whether the eighteen total isolated phenotypes were different species or not, 16S rDNA analysis of all the strains was performed. Table 1 shows the 16S rDNA sequence homology of the strains. Each isolated strain obtained from the agar plates was identified to be unrelated.
Table 1 showed that the cultivable microorganism diversity obtained in the same seawater was affected by the addition of DEF and HSL. Erwinia nigrifluens GMO4-1 and Shewanella putrefaciens GMO4-2 were identified from all seawater samples, and indicates that these two species were not influenced by either DEF and HSL. Pseudomonas doudoroffii. GMO4-3 was isolated from the unamended seawater and seawater amended with DEF, or DEF plus C8-HSL. Some strains could only be isolated from the seawater after the additions. For example, Cytophaga sp. GMO4-6, Sphingomonas sp. GMO4-11, and Beta proteobacterium strain GMO 4-10 were isolated from the seawater with DEF plus 3OC6-HSL; Cytophaga sp. GMO4-6 was also obtained from the community that was treated with DEF plus C8-HSL. Furthermore, GMO4-13, GMO4-14, GMO4-15, GMO4-16, GMO4-17 and GMO4-18 were found to be unknown species cultivated only from seawater that was amended with DEF, DEF plus 3OC6-HSL, C8-HSL, or DEF plus C8-HSL respectively.