IndexResultsSponge-associated bacteria with anti-Vibrio spp propertiesHemolytic reaction of potential bacteriaResultsIsolation of sponge-associated bacteria from 3 different sponges yielded 80 morphologically different bacterial isolates. Nine bacterial isolates were obtained from the sponge Hyrtios sp., 20 bacteria isolated from Smenospongia sp. and 51 bacteria isolated from Verungola sp. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay Sponge-associated bacteria with anti-Vibrio spp properties Twelve (15%) of 80 bacterial isolates were able to inhibit the growth of Vibrio indicated by the clear zone formation around the bacterial colony (Table 1). One bacterial strain (P2.24) could inhibit three Vibrio species, including V. harveyi, V. parahaemolyticus, and V. vulnificus. Furthermore, 10 bacterial strains specifically inhibit only V. harveyi, and 1 strain (P3.310) could inhibit both V. harveyi and V. parahaemolyticus. Twelve bacterial isolates showed different clear zone diameters, ranging from 0.1 mm to 5 mm. The best anti-Vibrio spp. activity shown by strain P2.24 thanks to its ability to inhibit three Vibrio species with different light zone diameters. To confirm its anti-Vibrio spp. activity, culture concentrate, supernatants, and metabolite extracts of strain P2.24 were tested in the antagonism assay. Hemolytic reaction of potential bacteria Twelve potential strains producing anti-Vibrio spp. the compounds were hemolytic negative. They fail to lyse the blood cells, as indicated by the absence of clear zones forming around the colony after 24 hours of incubation. Three (P2.24, P3.310, D4.13) out of 4 potential strains (based on their ability to inhibit Vibrio spp growth across broad spectra) were identified to have both NRPS and PKS genes, and one strain (P2. 211) does not have both genes, as shown in Table 2. Adenylase domain (A) of NRPS and ketosynthase domain (KS) of The PKS gene of these bacteria was amplified by the PCR method obtaining a DNA fragment of ± 1000 respectively bp and ± 700 bp (Fig. 1). Alignment using BlastN showed that all NRPS and PKS genes were similar to the NRPS and PKS genes of Bacillus spp in various strains. Furthermore, amplification of the 16S rRNA gene of four strains yielded a fragment of ±1300 bp. All three strains were highly homologous with Bacillus spp (Table 2). The genetic relationship for the NRPS-PKS gene of the potential strains was compared with their related gene in the NCBI GenBank database and with some references by constructing the phylogenetic tree. The phylogenetic tree of the A domain of the NRPS gene and the KS domain of the PKS gene was shown in Figure 2 and Figure 3, respectively. The 16S rRNA-based evolutionary relationship of the potential strains with the closely related strains was performed in Figure 4. Antibacterial activity of culture, supernatant and extract of strain P2.24 Please note: this is only a sample. Get a custom paper now from our expert writers. Get a Custom Assay The bacterial culture used in this test contains approximately 7.8 x 107 cells/mL of medium or 1.6 x 107 cells/20 µL. The culture, supernatant and extract of strain P2.24 consistently showed antibodies to Vibrio spp. activity as indicated by the formation of light areas around the paper disc (Fig.5). The strongest inhibitory effect was demonstrated by concentrated culture of strain P2.24 against V. parahaemolyticus. The clear zone was also shown by Ampicillin as a positive control. There is no clear zone obtained from DMSO as a negative control.