Department of Biological Environment and Chemistry, College of Agriculture and Life Sciences, Chungnam National University, Daejeon 305-764, Republic of Korea.
Chemosphere. 2013 Jan;90(2):479-87. doi: 10.1016/j.chemosphere.2012.08.006. Epub 2012 Sep 8.
A Gram positive, filamentous, spore forming antagonistic Streptomyces sp. AP-123 derived from marine region of Andra Pradesh, India, was studied for its medical importance. Among the 210 Streptomyces strains screened at 64.3% exhibited activity against Gram positive bacteria, 48.5% showed activity towards Gram negative bacteria, 38.8% exhibited both Gram positive and negative bacteria and 80.85% strains revealed significant antifungal activity. However, primary screening revealed that Streptomyces sp. AP-123 exhibited significant antimicrobial activity against all the tested bacteria compared to other Streptomyces strains. The presence of l-diaminopimelic acid and glycine in the cell wall hydrolysates and streptomycin resistance indicated the strain belonged to Streptomyces genus. The 16S rDNA gene based phylogenetic affiliation was determined by using bioinformatic tools and it was identified as Streptomyces sp. AP-123 with 99% sequence similarity to Streptomyces flavogriseus. The antimicrobial substances were extracted by hexane and ethyl acetate from spent medium in which Streptomyces sp. AP-123 was cultivated at 30 °C for 5 d. The antimicrobial activity was assessed using broth micro-dilution technique. A compound was obtained by eluting the crude extract using varying concentrations of solvents followed by the chromatographic purification. Based on the IR, (13)C NMR and (1)H NMR spectral data, the compound was identified as polyketide related antibiotic. It exhibited significant antibacterial activity against Gram positive and Gram negative bacteria and also showed a potent cytotoxic activity against cell lines viz. Vero (Green monkey kidney) and HEP2 (laryngeal carcinoma cells) in vitro. The lowest Minimum Inhibitory Concentration (MIC) of the compound against Bacillus subtilis and Staphylococcus aureus were 25 and 37.5 μg mL(-1), respectively. Against Escherichia coli and Pseudomonas aeruginosa it exhibited MIC of 50 and 37.58 μg mL(-1), respectively. However, against Candida albicans and filamentous fungus, Aspergillus niger the MIC values were 12.5 and 25 μg mL(-1), respectively. Cloning and sequence analysis of ketoacyl synthase (KS) gene revealed similarity to the type II polyketide synthase (PKS) gene of Streptomyces species.
一种革兰氏阳性、丝状、产孢子的拮抗链霉菌 AP-123 源自印度安得拉邦的海洋区域，因其医学重要性而被研究。在筛选的 210 株链霉菌菌株中，有 64.3%对革兰氏阳性菌有活性，48.5%对革兰氏阴性菌有活性，38.8%对革兰氏阳性菌和革兰氏阴性菌均有活性，80.85%的菌株显示出显著的抗真菌活性。然而，初步筛选表明，与其他链霉菌菌株相比，AP-123 对所有测试的细菌均表现出显著的抗菌活性。细胞壁水解物中存在 l-二氨基庚二酸和甘氨酸以及链霉素抗性表明该菌株属于链霉菌属。基于 16S rDNA 基因的系统发育关系通过生物信息学工具确定，并被鉴定为 AP-123 链霉菌，与 Streptomyces flavogriseus 的序列相似度为 99%。在 30°C 下培养 5 天后，从 AP-123 耗尽的培养基中用己烷和乙酸乙酯提取抗菌物质。使用肉汤微量稀释技术评估抗菌活性。通过用不同浓度的溶剂洗脱粗提取物获得化合物，然后进行色谱纯化。根据 IR、(13)C NMR 和 (1)H NMR 光谱数据，该化合物被鉴定为聚酮相关抗生素。它对革兰氏阳性和革兰氏阴性细菌表现出显著的抗菌活性，并且对细胞系 Vero（绿猴肾）和 HEP2（喉癌细胞）也表现出很强的细胞毒性活性。该化合物对枯草芽孢杆菌和金黄色葡萄球菌的最低最小抑菌浓度（MIC）分别为 25 和 37.5 μg/mL。对大肠杆菌和铜绿假单胞菌的 MIC 分别为 50 和 37.58 μg/mL。然而，对白色念珠菌和丝状真菌黑曲霉的 MIC 值分别为 12.5 和 25 μg/mL。酮酰基合酶（KS）基因的克隆和序列分析显示与链霉菌属的 II 型聚酮合酶（PKS）基因相似。
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