Khadayat Karan, Sherpa Dawa Dindu, Malla Krishna Prakash, Shrestha Sunil, Rana Nabin, Marasini Bishnu P, Khanal Santosh, Rayamajhee Binod, Bhattarai Bibek Raj, Parajuli Niranjan
Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu, Nepal.
Department of Biotechnology, National College, Tribhuvan University, Naya Bazar, Kathmandu, Nepal.
Int J Microbiol. 2020 Aug 27;2020:8817467. doi: 10.1155/2020/8817467. eCollection 2020.
are widely used for the production of secondary metabolites with diverse biological activities, including antibiotics. The necessity of alternative antimicrobial agents against multidrug-resistant pathogens is indispensable. However, the production of new therapeutics is delayed in recent days. Thus, the isolation of new species has drawn attention. Nepal-a country rich in biodiversity-has got high possibilities for the discovery of members of actinomycetes, especially in the higher altitudes. However, in vain, only a few screening research works have been reported from Nepal to date. species were isolated on ISP4 media, and characterization was performed according to morphological similarity and 16S rRNA sequence similarity using bioinformatic tools. Ethyl acetate extracts of species were prepared, and the antimicrobial activity was carried out using agar well diffusion technique. In this report, 18 species isolated from the soil were reported based on sequence analysis of 16S rRNA. Among them, 12 isolates have shown antibacterial activity against extended-spectrum beta-lactamase- (ESBL-) producing Here, we have also analyzed 16S rRNA in 27 species whose whole-genome sequence is available, which has revealed that some species have multiple copies of the 16S gene (∼1.5 kb) with significant variation in nucleotides. In contrast, some species shared identical DNA sequences in multiple copies of 16S rRNA. The sequencing of numerous copies of 16S rRNA is not necessary, and the molecular sequencing of this region is not sufficient for the identification of bacterial species. The species-derived ethyl acetate extracts from Nepalese soil demonstrate potential activity against ESBL-producing Thus, they are potential candidates for antibiotics manufacturing in the future.
放线菌被广泛用于生产具有多种生物活性的次生代谢产物，包括抗生素。对抗多重耐药病原体的替代抗菌剂的需求是必不可少的。然而，近年来新疗法的生产有所延迟。因此，新物种的分离引起了关注。尼泊尔——一个生物多样性丰富的国家——极有可能发现放线菌成员，尤其是在高海拔地区。然而，迄今为止，尼泊尔仅有少数筛选研究工作的报道，且均未成功。在ISP4培养基上分离出菌株，并使用生物信息学工具根据形态相似性和16S rRNA序列相似性进行鉴定。制备了菌株的乙酸乙酯提取物，并采用琼脂扩散法进行抗菌活性检测。在本报告中，基于16S rRNA序列分析，报道了从土壤中分离出的18株放线菌。其中，12株分离物对产超广谱β-内酰胺酶（ESBL）的细菌显示出抗菌活性。在此，我们还分析了27株全基因组序列已知的放线菌的16S rRNA，结果表明一些物种有多个16S基因（约1.5 kb）拷贝，其核苷酸存在显著差异。相反，一些放线菌物种在多个16S rRNA拷贝中共享相同的DNA序列。对多个16S rRNA拷贝进行测序没有必要，并且该区域的分子测序不足以鉴定细菌物种。从尼泊尔土壤中分离出的放线菌菌株的乙酸乙酯提取物对产ESBL的细菌显示出潜在活性。因此，它们是未来抗生素生产的潜在候选者。
