Department of Medical Biotechnology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
Department of Clinical Biochemistry, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
Sci Rep. 2023 Aug 12;13(1):13145. doi: 10.1038/s41598-023-40478-x.
The arbitrary and overuses of antibiotics have resulted in the emergence of multidrug resistance bacteria which encounters human to a serious public health problem. Thus, there is an ever-increasing demand for discovery of novel effective antibiotics with new modes of function against resistant pathogens. Endophytic actinobacteria (EA) have currently been considered as one of the most prospective group of microorganisms for discovery of therapeutic agents. This study aimed to isolate EA from Thymes kotschyanus, Allium hooshidaryae, and Cerasus microcarpa plants and to evaluate their antibacterial properties. The healthy samples were collected, dissected and surface-sterilized before cultured on four different selection media at 28 °C. Nine EA were isolated and identified based on morphological and molecular properties, and scanning electron micrograph analyses. Based on phylogenetic analysis, they were taxonomically grouped into four families Streptomycetaceae, Nocardiaceae, Micromonosporaceae, and Pseudonocardiaceae. Their branched aerial mycelia produced chains of cylindrical or cube or oval shaped spores with smooth or rough surfaces. Four strains; IKBG03, IKBG05, IKBG13, and IKBG17 had less than 98.65% sequence similarity to their closely related strains, which constitute them as novel species/strains. Besides, three strains; IKBG05, IKBG13, and IKBG18 were reported as endophytes for the first time. Preliminary antibacterial activity conducted on the all isolates revealed potent antibacterial effects against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. All isolates strongly inhibited the growth of at least one of the tested pathogens. Our results reveals that the test plants are novel sources for isolating a diverse group of rare and common actinobacteria that could produce a wide range of novel biologically active natural products with antibacterial activity which have a great potential in pharmaceutical and biotechnological applications.
抗生素的任意和过度使用导致了多药耐药菌的出现，这给人类带来了严重的公共卫生问题。因此，人们对发现具有针对耐药病原体的新作用模式的新型有效抗生素的需求不断增加。内生放线菌（EA）目前被认为是发现治疗剂最有前途的微生物群体之一。本研究旨在从 Thymes kotschyanus、Allium hooshidaryae 和 Cerasus microcarpa 植物中分离内生放线菌，并评估其抗菌特性。在 28°C 下，将健康的样本收集、解剖并进行表面消毒，然后在四种不同的选择培养基上进行培养。根据形态和分子特性以及扫描电子显微镜分析，从这些样本中分离和鉴定了 9 株内生放线菌。基于系统发育分析，它们在分类上被分为四个科：链霉菌科、诺卡氏菌科、小单孢菌科和假诺卡氏菌科。它们的分支气生菌丝产生链状的圆柱形、立方体形或椭圆形孢子，表面光滑或粗糙。其中 4 株菌（IKBG03、IKBG05、IKBG13 和 IKBG17）与亲缘关系较近的菌株的序列相似度小于 98.65%，构成了新的种/株。此外，有 3 株菌（IKBG05、IKBG13 和 IKBG18）是首次被报道为内生菌。对所有分离株进行的初步抗菌活性研究表明，它们对金黄色葡萄球菌、大肠杆菌和铜绿假单胞菌具有很强的抗菌作用。所有分离株都强烈抑制了至少一种测试病原体的生长。我们的研究结果表明，这些测试植物是分离具有广泛生物活性的新型抗菌天然产物的新型放线菌的丰富来源，这些天然产物在制药和生物技术应用中具有很大的潜力。
