Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, Belgrade, 11000, Serbia.
Department of Biotechnology and Pharmaceutical Engineering, Faculty of Technology, University of Novi Sad, Novi Sad, Serbia.
Int Microbiol. 2019 Sep;22(3):343-353. doi: 10.1007/s10123-019-00054-8. Epub 2019 Jan 9.
The objective of the present study was to isolate Actinobacteria, preferably Streptomyces spp. from the rhizosphere soils of three ethno-medicinal plants collected in Serbia (Papaver rhoeas, Matricaria chamomilla, and Urtica dioica) and to screen their antifungal activity against Candida spp. Overall, 103 sporulating isolates were collected from rhizosphere soil samples and determined as Streptomyces spp. Two different media and two extraction procedures were used to facilitate identification of antifungals. Overall, 412 crude cell extracts were tested against Candida albicans using disk diffusion assays, with 42% (43/103) of the strains showing the ability to produce antifungal agents. Also, extracts inhibited growth of important human pathogens: Candida krusei, Candida parapsilosis, and Candida glabrata. Based on the established degree and range of antifungal activity, nine isolates, confirmed as streptomycetes by 16S rRNA sequencing, were selected for further testing. Their ability to inhibit Candida growth in liquid culture, to inhibit biofilm formation, and to disperse pre-formed biofilms was assessed with active concentrations from 8 to 250 μg/mL. High-performance liquid chromatographic profiles of extracts derived from selected strains were recorded, revealing moderate metabolic diversity. Our results proved that rhizosphere soil of ethno-medicinal plants is a prolific source of streptomycetes, producers of potentially new antifungal compounds.
本研究的目的是从塞尔维亚采集的三种民族药用植物（罂粟、春黄菊和荨麻）的根际土壤中分离放线菌，最好是链霉菌属，并筛选其对念珠菌属的抗真菌活性。总体而言，从根际土壤样本中收集了 103 个产孢分离株，并确定为链霉菌属。使用两种不同的培养基和两种提取程序来促进抗真菌剂的鉴定。总体而言，使用纸片扩散法对 412 个粗细胞提取物进行了抗白色念珠菌的测试，其中 42%（43/103）的菌株具有产生抗真菌剂的能力。此外，提取物还抑制了重要的人类病原体：克柔念珠菌、近平滑念珠菌和光滑念珠菌的生长。基于建立的抗真菌活性程度和范围，选择了 9 个经 16S rRNA 测序确认为链霉菌的分离株进行进一步测试。评估了它们在液体培养中抑制念珠菌生长、抑制生物膜形成和分散已形成生物膜的能力，有效浓度为 8 至 250μg/ml。从选定菌株中提取的提取物的高效液相色谱图谱被记录下来，显示出中等的代谢多样性。我们的研究结果证明，民族药用植物的根际土壤是链霉菌的丰富来源，是潜在新抗真菌化合物的生产者。
