1
|
Mazumdar R, Saikia K, Thakur D. Potentiality of Actinomycetia Prevalent in Selected Forest Ecosystems in Assam, India to Combat Multi-Drug-Resistant Microbial Pathogens. Metabolites 2023; 13:911. [PMID: 37623855 PMCID: PMC10456813 DOI: 10.3390/metabo13080911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/15/2023] [Accepted: 07/25/2023] [Indexed: 08/26/2023] Open
Abstract
Actinomycetia are known for their ability to produce a wide range of bioactive secondary metabolites having significant therapeutic importance. This study aimed to explore the potential of actinomycetia as a source of bioactive compounds with antimicrobial properties against multi-drug-resistant (MDR) clinical pathogens. A total of 65 actinomycetia were isolated from two unexplored forest ecosystems, namely the Pobitora Wildlife Sanctuary (PWS) and the Deepor Beel Wildlife Sanctuary (DBWS), located in the Indo-Burma mega-biodiversity hotspots of northeast India, out of which 19 isolates exhibited significant antimicrobial activity. 16S rRNA gene sequencing was used for the identification and phylogenetic analysis of the 19 potent actinomycetia isolates. The results reveal that the most dominant genus among the isolates was Streptomyces (84.21%), followed by rare actinomycetia genera such as Nocardia, Actinomadura, and Nonomuraea. Furthermore, seventeen of the isolates tested positive for at least one antibiotic biosynthetic gene, specifically type II polyketide synthase (PKS-II) and nonribosomal peptide synthetases (NRPSs). These genes are associated with the production of bioactive compounds with antimicrobial properties. Among the isolated strains, three actinomycetia strains, namely Streptomyces sp. PBR1, Streptomyces sp. PBR36, and Streptomyces sp. DBR11, demonstrated the most potent antimicrobial activity against seven test pathogens. This was determined through in vitro antimicrobial bioassays and the minimum inhibitory concentration (MIC) values of ethyl acetate extracts. Gas chromatography-mass spectrometry (GS-MS) and whole-genome sequencing (WGS) of the three strains revealed a diverse group of bioactive compounds and secondary metabolite biosynthetic gene clusters (smBGCs), respectively, indicating their high therapeutic potential. These findings highlight the potential of these microorganisms to serve as a valuable resource for the discovery and development of novel antibiotics and other therapeutics with high therapeutic potential.
Collapse
Affiliation(s)
- Rajkumari Mazumdar
- Microbial Biotechnology Laboratory, Life Sciences Division, Institute of Advanced Study in Science and Technology (IASST), Guwahati 781035, India;
- Department of Molecular Biology & Biotechnology, Cotton University, Guwahati 781001, India
| | - Kangkon Saikia
- Bioinformatics Infrastructure Facility, Institute of Advanced Study in Science and Technology, Guwahati 781035, India;
| | - Debajit Thakur
- Microbial Biotechnology Laboratory, Life Sciences Division, Institute of Advanced Study in Science and Technology (IASST), Guwahati 781035, India;
| |
Collapse
|
2
|
Harunari E, Mae S, Igarashi Y. Microbispofurans A-C, plant growth-promoting furancarboxylic acids from plant root-derived Microbispora sp. J Antibiot (Tokyo) 2023:10.1038/s41429-023-00614-1. [PMID: 37016013 DOI: 10.1038/s41429-023-00614-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 02/16/2023] [Accepted: 03/16/2023] [Indexed: 04/06/2023]
Abstract
Microbispofurans A-C (1-3), new alkyl/alkenyl furancarboxylic acids, were isolated from the culture extract of the plant root-derived Microbispora sp. RD004716. The planar structures of 1-3 were determined by extensive analysis of 1D and 2D NMR spectroscopic data. Although 1-3 showed no appreciable antimicrobial activity or cytotoxicity, strong plant growth-promotion activity of the germinated red leaf lettuce seeds was observed at 10 μM. Furancarboxylic acids and their methyl esters were found in actinomycetes and fungi; however, the isolation of furandicarboxylic acid was unprecedented.
Collapse
Affiliation(s)
- Enjuro Harunari
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Shunsuke Mae
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Yasuhiro Igarashi
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan.
| |
Collapse
|
3
|
Sun YC, Sun P, Xue J, Du Y, Yan H, Wang LW, Yi XX, Sun JG, Zhang X, Gao JL. Arthrobacter wenxiniae sp. nov., a novel plant growth-promoting rhizobacteria species harbouring a carotenoids biosynthetic gene cluster. Antonie van Leeuwenhoek 2022; 115:353-364. [PMID: 35088183 DOI: 10.1007/s10482-021-01701-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 12/10/2021] [Indexed: 10/19/2022]
Abstract
A bacterial strain, designated AETb3-4T was isolated from the rhizosphere of lily. Comparison of 16S rRNA gene sequences showed that the sequence from strain AETb3-4T exhibits high sequence similarity with those of Arthrobacter silviterrae KIS14-16T (97.9%), Arthrobacter livingstonensis LI2T (97.2%) and Arthrobacter stackebrandtii CCM 2783T (97.0%). Whole genome average nucleotide identity (ANI) and the digital DNA-DNA hybridization (dDDH) values between strain AETb3-4T and the reference strains A. silviterrae DSM 27180T, A. livingstonensis L12T and A. stackebrandtii DSM 16005T were below 83.6% and 27.7%, respectively, values which are considerably below the proposed thresholds for the species delineation, consistent with the proposal that strain AETb3-4T represents a novel species. The genome size of strain AETb3-4T is 4.33 Mb and the genomic DNA G + C content is 67.3%. The main polar lipids were identified as phosphatidylglycerol, diphosphatidylglycero, phosphatidylinositol and an unidentified glycolipid. The major fatty acids (> 10%) were identified as anteiso-C15: 0 and anteiso-C17: 0. The predominant menaquinone was found to be menaquinone 9 (MK-9) (H2) (82.2%). Phenotypic tests allowed the strain to be differentiated from its close phylogenetic neighbors. Based on the results obtained, it is proposed that the strain AETb3-4T (= CFCC 16390T = LMG 31708T) represents a novel species in the genus Arthrobacter, for which the names Arthrobacter wenxiniae sp. nov. is proposed. In addition, the novel strain AETb3-4T has multiple plant growth-promoting characters including ACC-deaminase activity and production of IAA. Furthermore, the genome contains secondary metabolite biosynthesis gene clusters, including a carotenoid biosynthetic gene cluster, suggesting potential capacities for secondary metabolite synthesis. These data suggest that strain AETb3-4T may have potential applications both in medicine and sustainable agriculture.
Collapse
Affiliation(s)
- Yu-Chen Sun
- Institute of Grassland, Flowers and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, People's Republic of China.,College of Food Science and Engineering, Beijing University of Agriculture, Beijing, 102206, People's Republic of China
| | - Pengbo Sun
- Division of Pediatric Neurooncology, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.,German Cancer Consortium(DKTK), German Cancer Research Center(DKFZ), 69120, Heidelberg, Germany
| | - Jing Xue
- Institute of Grassland, Flowers and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, People's Republic of China
| | - Yunpeng Du
- Institute of Grassland, Flowers and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, People's Republic of China
| | - Hui Yan
- College of Animal Science and Technology, Hebei Agricultural University, Baoding, 071001, People's Republic of China
| | - Li-Wei Wang
- Institute of Grassland, Flowers and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, People's Republic of China
| | - Xin-Xin Yi
- College of Food Science and Engineering, Beijing University of Agriculture, Beijing, 102206, People's Republic of China
| | - Jian-Guang Sun
- Key Laboratory of Microbial Resources, Ministry of Agriculture/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, People's Republic of China
| | - Xiuhai Zhang
- Institute of Grassland, Flowers and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, People's Republic of China.
| | - Jun-Lian Gao
- Institute of Grassland, Flowers and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, People's Republic of China.
| |
Collapse
|
4
|
Engineering Pseudochelin Production in Myxococcus xanthus. Appl Environ Microbiol 2018; 84:AEM.01789-18. [PMID: 30217842 DOI: 10.1128/aem.01789-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 09/01/2018] [Indexed: 12/15/2022] Open
Abstract
Myxobacteria utilize the catechol natural products myxochelin A and B in order to maintain their iron homeostasis. Recently, the production of these siderophores, along with a new myxochelin derivative named pseudochelin A, was reported for the marine bacterium Pseudoalteromonas piscicida S2040. The latter derivative features a characteristic imidazoline moiety, which was proposed to originate from an intramolecular condensation reaction of the β-aminoethyl amide group in myxochelin B. To identify the enzyme catalyzing this conversion, we compared the myxochelin regulons of two myxobacterial strains that produce solely myxochelin A and B with those of P. piscicida S2040. This approach revealed a gene exclusive to the myxochelin regulon in P. piscicida S2040, coding for an enzyme of the amidohydrolase superfamily. To prove that this enzyme is indeed responsible for the postulated conversion, the reaction was reconstituted in vitro using a hexahistidine-tagged recombinant protein made in Escherichia coli, with myxochelin B as the substrate. To test the production of pseudochelin A under in vivo conditions, the amidohydrolase gene was cloned into the myxobacterial plasmid pZJY156 and placed under the control of a copper-inducible promoter. The resulting vector was introduced into the myxobacterium Myxococcus xanthus DSM 16526, a native producer of myxochelin A and B. Following induction with copper, the myxobacterial expression strain was found to synthesize small quantities of pseudochelin A. Replacement of the copper-inducible promoter with the constitutive pilA promoter led to increased production levels in M. xanthus, which facilitated the isolation and subsequent structural verification of the heterologously produced compound.IMPORTANCE In this study, an enzyme for imidazoline formation in pseudochelin biosynthesis was identified. Evidence for the involvement of this enzyme in the postulated reaction was obtained after in vitro reconstitution. Furthermore, the function of this enzyme was demonstrated in vivo by transferring the corresponding gene into the bacterium Myxococcus xanthus, which thereby became a producer of pseudochelin A. In addition to clarifying the molecular basis of imidazoline formation in siderophore biosynthesis, we describe the heterologous expression of a gene in a myxobacterium without chromosomal integration. Due to its metabolic proficiency, M. xanthus represents an interesting alternative to established host systems for the reconstitution and manipulation of biosynthetic pathways. Since the plasmid used in this study is easily adaptable for the expression of other enzymes as well, we expand the conventional expression strategy for myxobacteria, which is based on the integration of biosynthetic genes into the host genome.
Collapse
|