Isolation of marine bacteria with antimicrobial activities from cultured and field-collected soft corals

Abstract

Bacteria associated with eight field-collected and five cultured soft corals of Briareum sp., Sinularia sp., Sarcophyton sp., Nephtheidae sp., and Lobophytum sp. were screened for their abilities in producing antimicrobial metabolites. Field-collected coral samples were collected from Nanwan Bay in southern Taiwan. Cultured corals were collected from the cultivating tank at National Museum of Marine Biology and Aquarium. A total of 1,526 and 1,138 culturable, heterotrophic bacteria were isolated from wild and cultured corals, respectively; seawater requirement and antimicrobial activity were then assessed. There is no significant difference between the ratio of seawater-requiring bacteria on the wild and cultured corals. The ratio of antibiotic-producing bacteria within the seawater-requiring bacteria did not differ between the corals. Nineteen bacterial strains that showed high antimicrobial activity were selected for 16S rDNA sequencing. Three strains could be assigned at the family level (Rhodobacteraceae). The remaining 16 strains belong to eight genera: Marinobacterium (2 strains), Pseudoalteromonas (1), Vibrio (5), Enterovibrio (1), Tateyamaria (1), Labrenzia (2), and Pseudovibrio (4). The crude extract from bacteria strains CGH2XX was found to have high cytotoxicity against the cancer cell line HL-60 (IC(50) = 0.94 μg/ml) and CCRF-CEM (IC(50) = 1.19 μg/ml). Our results demonstrate that the marine bacteria from corals have great potential in the discovery of useful medical molecules.

Phytochemical Investigation and Assessment of Antioxidant and Antimicrobial Activities of Phagnalon barbeyanum Aerial Parts

“…Total methanol extract, methylene chloride, ethyl acetate and n-butanol fractions dissolved in DMSO and adjusted at concentration 50 mg/ml 15 . Overnight cultures of standard pathogenic strains were prepared in nutrient agar at 37 o C. Pure colonies of overnight plates were picked up and inoculated in 10 ml of 0.9% normal saline, and the turbidity adjusted to be equivalent to 0.5 McFarland standards, then the optical densities (ODs) of cell suspensions were adjusted to obtain 0.45 absorbance units at λmax 650 nm.…”

Diversity and antagonistic potential of bacteria isolated from marine grass Halodule uninervis

“…These approaches include their ability to produce different metabolic pathways in competitive environment of sea (Harvey 2008). This is the reason that most of the marine antimicrobial compounds previously reported are originated from marine host surface-attached bacteria (Shin et al 2007;Chen et al 2012).…”

High‐performance liquid chromatography/electrospray ionisation mass spectrometric characterisation of metabolites produced by Pseudovibrio sp. W64, a marine sponge derived bacterium isolated from Irish waters

“…Biosynthesis of tropodithietic acid (TDA), a tropolone antibiotic, has been observed in a number of strains of this genus . TDA has been shown to be active against a broad spectrum of human and fish pathogens, including Morganella morganii and Pandoraeae sputorum , both multidrug‐resistant opportunistic pathogens commonly associated with nosocomial infections . TDA‐producing Pseudovibrio isolates also displayed antimicrobial activity against Salmonella enterica sp.…”

“…4 TDA has been shown to be active against a broad spectrum of human and fish pathogens, including Morganella morganii and Pandoraeae sputorum, both multidrug-resistant opportunistic pathogens commonly associated with nosocomial infections. [17][18][19] TDA-producing Pseudovibrio isolates also displayed antimicrobial activity against Salmonella enterica sp. arizonae and S. aureus, one of the top three pathogens of blood stream infections.…”