Tanvir Rabia, Sajid Imran, Hasnain Shahida, Kulik Andreas, Grond Stephanie
Department of Microbiology and Molecular Genetics, University of the Punjab, Quaid-e-Azam Campus, 54590, Lahore, Punjab, Pakistan; Institut fur Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18A, 72076, Tübingen, Germany.
Department of Microbiology and Molecular Genetics, University of the Punjab, Quaid-e-Azam Campus, 54590, Lahore, Punjab, Pakistan.
Microbiol Res. 2016 Apr;185:22-35. doi: 10.1016/j.micres.2016.01.003. Epub 2016 Jan 23.
Two strains identified as Nocardia caishijiensis (SORS 64b) and Pseudonocardia carboxydivorans (AGLS 2) were isolated as endophytes from Sonchus oleraceus and Ageratum conyzoides respectively. The analysis of their extracts revealed them to be strongly bioactive. The N. caishijiensis extract gave an LC50 of 570 μg/ml(-1) in the brine shrimp cytotoxicity assay and an EC50 of 0.552 μg/ml(-1) in the DPPH antioxidant assay. Antimicrobial activity was observed against Methicillin resistant Staphlococcus aureus (MRSA) and Escherichia coli ATCC 25922 (14 mm), Klebsiella pneumoniae ATCC 706003 (13 mm), S. aureus ATCC 25923 (11 mm) and Candida tropicalis (20 mm). For the extract of P. carboxydivorans the EC50 was 0.670 μg/ml(-1) and it was observed to be more bioactive against Bacillus subtilis DSM 10 ATCC 6051 (21 mm), C. tropicalis (20 mm), S. aureus ATCC 25923 (17 mm), MRSA (17 mm), E. coli K12 (W1130) (16 mm) and Chlorella vulgaris (10 mm). The genotoxicity testing revealed a 20 mm zone of inhibition against the polA mutant strain E. coli K-12 AB 3027 suggesting damage to the DNA and polA genes. The TLC and bioautography screening revealed a diversity of active bands of medium polar and nonpolar compounds. Metabolite analysis by HPLC-DAD via UV/vis spectral screening suggested the possibility of stenothricin and bagremycin A in the mycelium extract of N. caishijiensis respectively. In the broth and mycelium extract of P. carboxydivorans borrelidin was suggested along with α-pyrone. The HPLC-MS revealed bioactive long chained amide derivatives such as 7-Octadecenamide, 9, 12 octadecandienamide. This study reports the rare actinomycetes N. caishijiensis and P. carboxydivorans as endophytes and evaluates their bioactive metabolites.
从苦苣菜和藿香蓟中分别分离出两株内生菌，经鉴定为采氏诺卡氏菌（SORS 64b）和羧基营养假诺卡氏菌（AGLS 2）。对其提取物的分析表明它们具有很强的生物活性。采氏诺卡氏菌提取物在卤虫细胞毒性试验中的LC50为570μg/ml(-1)，在DPPH抗氧化试验中的EC50为0.552μg/ml(-1)。观察到其对耐甲氧西林金黄色葡萄球菌（MRSA）和大肠埃希菌ATCC 25922（抑菌圈直径14mm）、肺炎克雷伯菌ATCC 706003（13mm）、金黄色葡萄球菌ATCC 25923（11mm）和热带假丝酵母（20mm）具有抗菌活性。羧基营养假诺卡氏菌提取物的EC50为0.670μg/ml(-1)，观察到其对枯草芽孢杆菌DSM 10 ATCC 6051（21mm）、热带假丝酵母（20mm）、金黄色葡萄球菌ATCC 25923（17mm）、MRSA（17mm）、大肠埃希菌K12（W1130）（16mm）和普通小球藻（10mm）具有更强的生物活性。遗传毒性测试显示，对polA突变株大肠埃希菌K-12 AB 3027有20mm的抑菌圈，表明对DNA和polA基因有损伤。TLC和生物自显影筛选显示出多种中极性和非极性化合物的活性条带。通过HPLC-DAD经紫外/可见光谱筛选进行的代谢物分析表明，采氏诺卡氏菌的菌丝体提取物中分别可能存在窄霉素和巴格雷霉素A。在羧基营养假诺卡氏菌的肉汤和菌丝体提取物中，除α-吡喃酮外，还推测有博来霉素。HPLC-MS显示出生物活性长链酰胺衍生物，如7-十八碳烯酰胺、9,12-十八碳二烯酰胺。本研究报道了罕见的放线菌采氏诺卡氏菌和羧基营养假诺卡氏菌作为内生菌，并评估了它们的生物活性代谢物。
