从高温生态系统中的土壤细菌中生物勘探具有抗菌特性的次生代谢产物。

Bioprospecting secondary metabolites with antimicrobial properties from soil bacteria in high-temperature ecosystems.

作者信息

Demisie Sisay, Oh Dong-Chan, Abera Adugna, Tasew Geremew, Satessa Gizaw Dabessa, Fufa Fetene, Shenkutie Abebe Mekuria, Wolday Dawit, Tafess Ketema

机构信息

Department of Applied Biology, School of Applied Natural Science, Adama Science and Technology University, P. O. Box 1888, Adama, Ethiopia.

College of Pharmacy, Natural Products Research Institute, Seoul National University, Seoul, 08826, Republic of Korea.

出版信息

Microb Cell Fact. 2024 Dec 19;23(1):332. doi: 10.1186/s12934-024-02589-6.

DOI:10.1186/s12934-024-02589-6

PMID:39696555

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC11657271/

Abstract

BACKGROUND

The ongoing emergence and spread of drug-resistant pathogens necessitate urgent solutions. Natural products from bacterial sources are recognized as a promising source of antibiotics. This study aimed to isolate and characterize soil microorganisms from extremely hot environments and to screen their secondary metabolites for antibacterial activity.

METHODS

Bacterial isolates were identified using standard culture techniques. Primary and secondary screenings for antimicrobial activity were conducted using the Modified Kirby-Bauer antibiotic susceptibility test against five bacterial species. Based on the efficacy of antimicrobial activity against these target pathogens, the isolate Pseudomonas sp. strain ASTU00105 was selected for further characterization through whole genomic sequencing. Secondary metabolites were analyzed using GC-MS, and antioxidant activities were also evaluated.

RESULTS

A total of 76 isolates were identified, and their secondary metabolites were tested against Escherichia coli, Salmonella typhi, Acinetobacter baumannii, Staphylococcus aureus, Streptococcus pyogenes, and Candida albicans. Seventeen isolates (22.37%) exhibited antimicrobial activity. Isolate ASTU00105 exhibited the highest activity against all the test organisms and was selected for further analysis. Whole-genome sequencing using the Nanopore MinION sequencer revealed that strain ASTU00105 belonged to the genus Pseudomonas with the highest similarity (95.97%) to Pseudomonas stutzeri, and designated as Pseudomonas sp. strain ASTU00105. Upon Average Nucleotide Identity (ANI) analysis, the strain exhibited 87.81% sequence similarity with genes of the closest type strain, suggesting its novelty and distinctiveness within the Pseudomonas genus. The genomic analysis of the isolated strain revealed 6 biosynthetic gene cluster (BGC) genes dispersed throughout the entire genome, which are implicated in the synthesis of antimicrobial secondary metabolites. The major chemical compounds detected in the EtAc extracts as detected by gas chromatography-mass spectrometry (GC-MS) were phenol, 2,5-bis (1,1-dimethylethyl) (36.6%), followed by 1,2-Benzenedicarboxylic acid, diethyl ester (12.22%), Eicosane (9.71%), Dibutyl phthalate (3.93%), and 1-Dodecanol (2.34%).

IN CONCLUSION

Pseudomonas sp. strain ASTU00105 exhibited the greatest potential for producing secondary metabolites with significant antimicrobial activity.

摘要

背景

耐药病原体的不断出现和传播迫切需要解决方案。细菌来源的天然产物被认为是一种有前景的抗生素来源。本研究旨在从极端炎热环境中分离和鉴定土壤微生物，并筛选其次级代谢产物的抗菌活性。

方法

使用标准培养技术鉴定细菌分离株。采用改良的 Kirby-Bauer 抗生素敏感性试验对五种细菌进行抗菌活性的初筛和复筛。基于对这些目标病原体的抗菌活性效果，选择分离株假单胞菌属菌株 ASTU00105 通过全基因组测序进行进一步鉴定。使用气相色谱 - 质谱联用仪（GC-MS）分析次级代谢产物，并评估抗氧化活性。

结果

共鉴定出 76 株分离株，并针对大肠杆菌、伤寒沙门氏菌、鲍曼不动杆菌、金黄色葡萄球菌、化脓性链球菌和白色念珠菌测试了其次级代谢产物。17 株分离株（22.37%）表现出抗菌活性。分离株 ASTU00105 对所有测试生物均表现出最高活性，并被选作进一步分析。使用纳米孔 MinION 测序仪进行的全基因组测序显示，菌株 ASTU00105 属于假单胞菌属，与施氏假单胞菌的相似度最高（95.97%），并命名为假单胞菌属菌株 ASTU00105。通过平均核苷酸同一性（ANI）分析，该菌株与最接近的模式菌株的基因序列相似度为 87.81%，表明其在假单胞菌属内具有新颖性和独特性。对分离菌株的基因组分析揭示了 6 个生物合成基因簇（BGC）基因分散在整个基因组中，这些基因与抗菌次级代谢产物的合成有关。气相色谱 - 质谱联用仪（GC-MS）检测到的乙酸乙酯提取物中的主要化合物为苯酚，2,5 - 双（1,1 - 二甲基乙基）（36.6%），其次是邻苯二甲酸二乙酯（12.22%）、二十烷（9.71%）、邻苯二甲酸二丁酯（3.93%）和 1 - 十二醇（2.34%）。