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The Importance Of Sediment

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Sediment samples were taken from 14 stations during the cruise program organized by the Persian Gulf and Oman Sea Ecological Research Institute (PGOSERI), Bandar Abbas, Iran in February 2014. The sediment samples were collected by Van Veen Grab sampler (Hydro-bios, Germany) and then were transferred to sterilized 50 ml tubes, and were kept refrigerated until shipboard processing later that day. The position and depth of sampling stations were recorded (Fig. 1).
Selective isolation of actinomycetes
Two physical treatments and four isolation media were implemented. Drying treatment was applied by desiccation of sediment samples in a laminar flow hood for a week. After grinding and fivefold serial dilution, the samples were inoculated on…show more content…
The purified isolates were inoculated into 50 ml of the Hickey Tresner broth medium (DSMZ) prepared with filtered seawater. The seeded media were incubated in a shaking incubator (220 rpm) at 28 ˚C for 5 days. After centrifugation, 100 µl of the culture supernatants were added to the punctured wells on the Muller Hinton agar (for bacteria) or Potato Dextrose Agar (for fungi) that previously inoculated with test strains. The test strains included Staphylococcus aureus ATCC 6538, Micrococcus luteus ATCC 10240, Escherichia coli ATCC 25922, Pseudomonas aeroginosa ATCC 27853, Aspergillus niger PTCC 5057 and Candida albicans ATCC 10231. The antimicrobial activity of the culture broths were determined by measurement of the inhibition zone diameters (mm) after the incubation period at 35 ˚C (Madigan et al., 1997).
Production and extraction of antimicrobial secondary metabolites
The selected potent isolates were inoculated to the seeding medium containing 1% malt extract, 1% peptone 2% glycerol and were incubated at 28 ˚C in shaking incubator (220 rpm) for 48 hours. After termination of the incubation, the seeded cultures were inoculated to the optimized production medium. After incubation for 5 days at 28˚C, the aliquots of filtrate-fermented broth were extracted with ethyl acetate twice (1:1 v/v). The ethyl acetate layers were evaporated and the crude extracts were kept for the subsequent experiments (Seidel,
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