Increasing concerns about the emergence of antibiotic-resistant bacteria have drawn much attention for research efforts to introduce new types of antibacterial compounds among scientists. In the present report, 24 bacterial strains isolated from the coastal areas of the Persian Gulf in Iran were investigated in order to assess their potentials to produce antibacterial metabolites. Among these, the crude extract from the isolate REB264 showed promising inhibition activity on the growth of two pathogenic bacteria, Pseudomonas aeruginosa and Staphylococcus aureus. Molecular identification via sequencing of the amplified 16S rDNA gene of the strain REB264 revealed that the bacterium belonging to the genus Bacillus and was tentatively named Bacillus sp. REB264, while the sequence was deposited in GenBank database, NCBI. Optimization of the carbon and nitrogen sources of the strain REB264 culture media determined that 743 mg/l active extract was achieved when using 1% glycerol and 0.5% yeast extract as carbon and nitrogen sources, respectively. Crude extract purification to obtain the antibacterial metabolite was performed in three steps using fractionation in organic and aqueous solvents, silica gel 60 column chromatography and LH-20 gel filtration with the yield of 80%. The purified compound exhibited inhibitory effect on P. aeruginosa growth at minimum inhibitory concentration (MIC) of 15 µg/ml, while lacking antibacterial effect on S. aureus. The P. aeruginosa growth inhibitor 264 (PAGI264) compound was further purified using reversed-phase high-performance liquid chromatography (C18-HPLC) up to 95% and the structural analysis by FTIR and H1-NMR confirmed that PAGI264 is composed of alcoholic, carbonyl and phenolic functional groups. Moreover, MS data in positive mode showed that the molecular weight of the compound is 761.74 Da. Lack of toxicity to MCF-7 cell line up to 500 µg/ml and lack of the hemolytic effect on red blood cells showed that the present natural product, PAGI264, has capability to use as a lead or drug in the future.

人们越来越关注抗生素抗性细菌的出现，这引起了科学家们对引入新型抗菌化合物的研究工作的极大关注。在本报告中，调查了从伊朗波斯湾沿海地区分离出的24种细菌菌株，以评估其产生抗菌代谢物的潜力。其中，分离株REB264的粗提物对铜绿假单胞菌和金黄色葡萄球菌这两种病原菌的生长显示出有希望的抑制活性。通过对菌株REB264的扩增的16S rDNA基因进行测序的分子鉴定表明，该细菌属于芽孢杆菌属，暂定名为芽孢杆菌sp。REB264，而该序列已保存在GenBank数据库NCBI中。菌株REB264培养基的碳源和氮源的优化确定，当分别使用1％甘油和0.5％酵母提取物作为碳源和氮源时，可获得743 mg / l的活性提取物。通过在有机和水性溶剂中分馏，硅胶60柱色谱法和LH-20凝胶过滤，分三步进行粗提物纯化以获得抗菌代谢物，产率为80％。纯化的化合物在最小抑菌浓度（MIC）为15 µg / ml时对铜绿假单胞菌的生长表现出抑制作用，而对金黄色葡萄球菌则没有抗菌作用。在铜绿假单胞菌使用反相高效液相色谱法（C18-HPLC）进一步纯化生长抑制剂264（PAGI264）化合物，其纯度高达95％，并且通过FTIR和H1-NMR进行的结构分析证实PAGI264由醇，羰基和酚基官能团组成组。此外，正模式的MS数据表明该化合物的分子量为761.74 Da。对高达500 µg / ml的MCF-7细胞系缺乏毒性，并且对红细胞没有溶血作用，这表明目前的天然产物PAGI264具有将来用作先导或药物的能力。