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Lam YC, Hamchand R, Mucci NC, Kauffman SJ, Dudkina N, Reagle EV, Casanova-Torres ÁM, DeCuyper J, Chen H, Song D, Thomas MG, Palm NW, Goodrich-Blair H, Crawford JM. The Xenorhabdus nematophila LrhA transcriptional regulator modulates production of γ-keto- N-acyl amides with inhibitory activity against mutualistic host nematode egg hatching. Appl Environ Microbiol 2024; 90:e0052824. [PMID: 38916293 PMCID: PMC11267870 DOI: 10.1128/aem.00528-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 06/01/2024] [Indexed: 06/26/2024] Open
Abstract
Xenorhabdus nematophila is a symbiotic Gammaproteobacterium that produces diverse natural products that facilitate mutualistic and pathogenic interactions in their nematode and insect hosts, respectively. The interplay between X. nematophila secondary metabolism and symbiosis stage is tuned by various global regulators. An example of such a regulator is the LysR-type protein transcription factor LrhA, which regulates amino acid metabolism and is necessary for virulence in insects and normal nematode progeny production. Here, we utilized comparative metabolomics and molecular networking to identify small molecule factors regulated by LrhA and characterized a rare γ-ketoacid (GKA) and two new N-acyl amides, GKA-Arg (1) and GKA-Pro (2) which harbor a γ-keto acyl appendage. A lrhA null mutant produced elevated levels of compound 1 and reduced levels of compound 2 relative to wild type. N-acyl amides 1 and 2 were shown to be selective agonists for the human G-protein-coupled receptors (GPCRs) C3AR1 and CHRM2, respectively. The CHRM2 agonist 2 deleteriously affected the hatch rate and length of Steinernema nematodes. This work further highlights the utility of exploiting regulators of host-bacteria interactions for the identification of the bioactive small molecule signals that they control. IMPORTANCE Xenorhabdus bacteria are of interest due to their symbiotic relationship with Steinernema nematodes and their ability to produce a variety of natural bioactive compounds. Despite their importance, the regulatory hierarchy connecting specific natural products and their regulators is poorly understood. In this study, comparative metabolomic profiling was utilized to identify the secondary metabolites modulated by the X. nematophila global regulator LrhA. This analysis led to the discovery of three metabolites, including an N-acyl amide that inhibited the egg hatching rate and length of Steinernema carpocapsae nematodes. These findings support the notion that X. nematophila LrhA influences the symbiosis between X. nematophila and S. carpocapsae through N-acyl amide signaling. A deeper understanding of the regulatory hierarchy of these natural products could contribute to a better comprehension of the symbiotic relationship between X. nematophila and S. carpocapsae.
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Affiliation(s)
- Yick Chong Lam
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- Institute of Biomolecular Design & Discovery, Yale University, West Haven, Connecticut, USA
| | - Randy Hamchand
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- Institute of Biomolecular Design & Discovery, Yale University, West Haven, Connecticut, USA
| | - Nicholas C. Mucci
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Sarah J. Kauffman
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Natavan Dudkina
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- Institute of Biomolecular Design & Discovery, Yale University, West Haven, Connecticut, USA
| | - Emily V. Reagle
- Institute of Biomolecular Design & Discovery, Yale University, West Haven, Connecticut, USA
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | - Jessica DeCuyper
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Haiwei Chen
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Deguang Song
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Michael G. Thomas
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Noah W. Palm
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Heidi Goodrich-Blair
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jason M. Crawford
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- Institute of Biomolecular Design & Discovery, Yale University, West Haven, Connecticut, USA
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
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Malfent F, Zehl M, Kirkegaard RH, Oberhofer M, Zotchev SB. Genomes and secondary metabolomes of Streptomyces spp. isolated from Leontopodium nivale ssp. alpinum. Front Microbiol 2024; 15:1408479. [PMID: 38946903 PMCID: PMC11212599 DOI: 10.3389/fmicb.2024.1408479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 05/13/2024] [Indexed: 07/02/2024] Open
Abstract
Bacterial endophytes dwelling in medicinal plants represent an as yet underexplored source of bioactive natural products with the potential to be developed into drugs against various human diseases. For the first time, several Streptomyces spp. were isolated from the rare and endangered traditional medicinal plant Leontopodium nivale ssp. alpinum, also known as Edelweiss. In the search for novel natural products, nine endophytic Streptomyces spp. from Edelweiss were investigated via genome sequencing and analysis, followed by fermentation in different media and investigation of secondary metabolomes. A total of 214 secondary metabolite biosynthetic gene clusters (BGCs), of which 35 are presumably unique, were identified by the bioinformatics tool antiSMASH in the genomes of these isolates. LC-MS analyses of the secondary metabolomes of these isolates revealed their potential to produce both known and presumably novel secondary metabolites, whereby most of the identified molecules could be linked to their cognate BGCs. This work sets the stage for further investigation of endophytic streptomycetes from Edelweiss aimed at the discovery and characterization of novel bioactive natural products.
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Affiliation(s)
- Fabian Malfent
- Division of Pharmacognosy, Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
- Vienna Doctoral School of Pharmaceutical, Nutritional and Sport Sciences (PhaNuSpo), University of Vienna, Vienna, Austria
| | - Martin Zehl
- Department of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Rasmus H. Kirkegaard
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
- Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna, Vienna, Austria
| | - Martina Oberhofer
- Division of Pharmacognosy, Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Sergey B. Zotchev
- Division of Pharmacognosy, Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
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Feng W, Lv C, Cheng L, Song X, Li X, Xie H, Chen S, Wang X, Xue L, Zhang C, Kou J, Wang L, Zhao H. Targeting ERS-mitophagy in hippocampal neurons to explore the improvement of memory by tea polyphenols in aged type 2 diabetic rats. Free Radic Biol Med 2024; 213:293-308. [PMID: 38286317 DOI: 10.1016/j.freeradbiomed.2024.01.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 01/15/2024] [Accepted: 01/26/2024] [Indexed: 01/31/2024]
Abstract
Increasing evidence demonstrated that mitophagy and endoplasmic reticulum stress (ERS) was closely associated with memory decline in elderly type 2 diabetes mellitus (T2DM). Tea polyphenols (TP), an excellent natural antioxidant, has been reported to have neuroprotective properties in aging and diabetes, but the underlying mechanisms are still not fully understood. This study targets ERS-mitophagy in hippocampal neurons to investigate the improvement effect of memory in aged T2DM rats by TP. Rats were randomly divided into the control group, the aged group, the aged T2DM model group, the TP 75, 150, 300 mg/kg groups. TP 300 mg/kg ameliorated mitophagy by decreasing the levels of p-mTOR (S2448), P62 and HSP60 and increasing the levels of PINK1 and Parkin, the ratio of LC3Ⅱ/LC3Ⅰ, co-localization of LC3 and HSP60 and the number of autophagosomes and autolysosomes. TP 300 mg/kg attenuated ERS by downregulating the levels of p-PERK, p-eIF2α, ATF4, GRP78 and restoring the ER structure. To further verify epigallocatechin gallate (EGCG), which is the main active component of TP, enhanced mitophagy by inhibiting ERS, PC12 cells were pretreated with ERS activator tunicamycin (TM) or ERS inhibitor 4-phenylbutyric acid (4-PBA). The results showed that the improvement of mitophagy by EGCG was inhibited by TM and promoted by 4-PBA. Collectively, ERS-mitophagy in hippocampal neurons plays a key role in the improvement of memory by TP in aged T2DM rats. This study will provide a new perspective and strategy for the prevention of memory decline in elderly with T2DM.
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Affiliation(s)
- Wenjuan Feng
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Chenhui Lv
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Le Cheng
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Xin Song
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Xuemin Li
- Center for Disease Control and Prevention in Shanxi Province, Taiyuan, Shanxi, 030012, PR China
| | - Haoran Xie
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Shuangzhi Chen
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Xi Wang
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Lushan Xue
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Cheng Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Jie Kou
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Lili Wang
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Haifeng Zhao
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China; Key Laboratory of Coal Environmental Pathogenicity and Prevention (Shanxi Medical University), Ministry of Education, PR China.
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Meesil W, Muangpat P, Sitthisak S, Rattanarojpong T, Chantratita N, Machado RAR, Shi YM, Bode HB, Vitta A, Thanwisai A. Genome mining reveals novel biosynthetic gene clusters in entomopathogenic bacteria. Sci Rep 2023; 13:20764. [PMID: 38007490 PMCID: PMC10676414 DOI: 10.1038/s41598-023-47121-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 11/09/2023] [Indexed: 11/27/2023] Open
Abstract
The discovery of novel bioactive compounds produced by microorganisms holds significant potential for the development of therapeutics and agrochemicals. In this study, we conducted genome mining to explore the biosynthetic potential of entomopathogenic bacteria belonging to the genera Xenorhabdus and Photorhabdus. By utilizing next-generation sequencing and bioinformatics tools, we identified novel biosynthetic gene clusters (BGCs) in the genomes of the bacteria, specifically plu00736 and plu00747. These clusters were identified as unidentified non-ribosomal peptide synthetase (NRPS) and unidentified type I polyketide synthase (T1PKS) clusters. These BGCs exhibited unique genetic architecture and encoded several putative enzymes and regulatory elements, suggesting its involvement in the synthesis of bioactive secondary metabolites. Furthermore, comparative genome analysis revealed that these BGCs were distinct from previously characterized gene clusters, indicating the potential for the production of novel compounds. Our findings highlighted the importance of genome mining as a powerful approach for the discovery of biosynthetic gene clusters and the identification of novel bioactive compounds. Further investigations involving expression studies and functional characterization of the identified BGCs will provide valuable insights into the biosynthesis and potential applications of these bioactive compounds.
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Affiliation(s)
- Wipanee Meesil
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand
| | - Paramaporn Muangpat
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand
| | - Sutthirat Sitthisak
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand
- Centre of Excellence in Medical Biotechnology (CEMB), Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand
| | - Triwit Rattanarojpong
- Department of Microbiology, Faculty of Science, King Mongkut's University of Technology Thonburi (KMUTT), Bangkok, 10400, Thailand
| | - Narisara Chantratita
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Ricardo A R Machado
- Experimental Biology Research Group, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland
| | - Yi-Ming Shi
- Department of Natural Products in Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
- Molecular Biotechnology, Department of Biosciences, Goethe University, Frankfurt, 60438, Frankfurt am Main, Germany
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Helge B Bode
- Department of Natural Products in Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
- Molecular Biotechnology, Department of Biosciences, Goethe University, Frankfurt, 60438, Frankfurt am Main, Germany
- Chemical Biology, Department of Chemistry, Philipps University Marburg, 35032, Marburg, Germany
- Senckenberg Gesellschaft für Naturforschung, Frankfurt am Main, Germany
- SYNMIKRO (Zentrum für Synthetische Mikrobiologie), 35032, Marburg, Germany
| | - Apichat Vitta
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand
- Centre of Excellence in Medical Biotechnology (CEMB), Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand
- Center of Excellence for Biodiversity, Faculty of Sciences, Naresuan University, Phitsanulok, 65000, Thailand
| | - Aunchalee Thanwisai
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand.
- Centre of Excellence in Medical Biotechnology (CEMB), Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand.
- Center of Excellence for Biodiversity, Faculty of Sciences, Naresuan University, Phitsanulok, 65000, Thailand.
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5
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Fan JQ, Zhao WF, Lu QW, Zha FR, Lv LB, Ye GL, Gao HL. Fecal microbial biomarkers combined with multi-target stool DNA test improve diagnostic accuracy for colorectal cancer. World J Gastrointest Oncol 2023; 15:1424-1435. [PMID: 37663945 PMCID: PMC10473925 DOI: 10.4251/wjgo.v15.i8.1424] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/20/2023] [Accepted: 06/19/2023] [Indexed: 08/10/2023] Open
Abstract
BACKGROUND Colorectal cancer (CRC) is a major global health burden. The current diagnostic tests have shortcomings of being invasive and low accuracy. AIM To explore the combination of intestinal microbiome composition and multi-target stool DNA (MT-sDNA) test in the diagnosis of CRC. METHODS We assessed the performance of the MT-sDNA test based on a hospital clinical trial. The intestinal microbiota was tested using 16S rRNA gene sequencing. This case-control study enrolled 54 CRC patients and 51 healthy controls. We identified biomarkers of bacterial structure, analyzed the relationship between different tumor markers and the relative abundance of related flora components, and distinguished CRC patients from healthy subjects by the linear discriminant analysis effect size, redundancy analysis, and random forest analysis. RESULTS MT-sDNA was associated with Bacteroides. MT-sDNA and carcinoembryonic antigen (CEA) were positively correlated with the existence of Parabacteroides, and alpha-fetoprotein (AFP) was positively associated with Faecalibacterium and Megamonas. In the random forest model, the existence of Streptococcus, Escherichia, Chitinophaga, Parasutterella, Lachnospira, and Romboutsia can distinguish CRC from health controls. The diagnostic accuracy of MT-sDNA combined with the six genera and CEA in the diagnosis of CRC was 97.1%, with a sensitivity and specificity of 98.1% and 92.3%, respectively. CONCLUSION There is a positive correlation of MT-sDNA, CEA, and AFP with intestinal microbiome. Eight biomarkers including six genera of gut microbiota, MT-sDNA, and CEA showed a prominent sensitivity and specificity for CRC prediction, which could be used as a non-invasive method for improving the diagnostic accuracy for this malignancy.
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Affiliation(s)
- Jin-Qing Fan
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Ningbo University, Ningbo 315000, Zhejiang Province, China
| | - Wang-Fang Zhao
- Department of Gastroenterology, The First Affiliated Hospital of Ningbo University, Ningbo 315000, Zhejiang Province, China
| | - Qi-Wen Lu
- Department of Gastroenterology, The First Affiliated Hospital of Ningbo University, Ningbo 315000, Zhejiang Province, China
| | - Fu-Rong Zha
- Department of Bioinformation Analysis, Shanghai BIOZERON Biotechnology Co., Shanghai 201800, China
| | - Le-Bin Lv
- Department of Preventive Medicine, The First Affiliated Hospital of Ningbo University, Ningbo 315000, Zhejiang Province, China
| | - Guo-Liang Ye
- Department of Gastroenterology, The First Affiliated Hospital of Ningbo University, Ningbo 315000, Zhejiang Province, China
| | - Han-Lu Gao
- Department of Preventive Medicine, The First Affiliated Hospital of Ningbo University, Ningbo 315000, Zhejiang Province, China
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Cosic A, Leitner E, Petternel C, Galler H, Reinthaler FF, Herzog-Obereder KA, Tatscher E, Raffl S, Feierl G, Högenauer C, Zechner EL, Kienesberger S. Corrigendum: Variation in accessory genes within the Klebsiella oxytoca species complex delineates monophyletic members and simplifies coherent genotyping. Front Microbiol 2023; 14:1155851. [PMID: 36960282 PMCID: PMC10028735 DOI: 10.3389/fmicb.2023.1155851] [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: 01/31/2023] [Accepted: 02/22/2023] [Indexed: 03/09/2023] Open
Abstract
[This corrects the article DOI: 10.3389/fmicb.2021.692453.].
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Affiliation(s)
- Amar Cosic
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Eva Leitner
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Christian Petternel
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Herbert Galler
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Franz F. Reinthaler
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Kathrin A. Herzog-Obereder
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Elisabeth Tatscher
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Sandra Raffl
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Gebhard Feierl
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Christoph Högenauer
- BioTechMed-Graz, Graz, Austria
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Ellen L. Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
| | - Sabine Kienesberger
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
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7
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Aguilar C, Verdel-Aranda K, Ramos-Aboites HE, Licona-Cassani C, Barona-Gómez F. Streptomyces lividans 66 produces a protease inhibitor via a tRNA-utilizing enzyme interacting with a C-minus NRPS. J Ind Microbiol Biotechnol 2023; 50:kuad021. [PMID: 37669898 PMCID: PMC10548850 DOI: 10.1093/jimb/kuad021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 08/25/2023] [Indexed: 09/07/2023]
Abstract
Small peptide aldehydes (SPAs) with protease inhibitory activity are naturally occurring compounds shown to be synthesized by non-ribosomal peptide synthetases (NRPS). SPAs are widely used in biotechnology and have been utilized as therapeutic agents. They are also physiologically relevant and have been postulated to regulate the development of their producing microorganisms. Previously, we identified an NRPS-like biosynthetic gene cluster (BGC) in Streptomyces lividans 66 that lacked a condensation (C) domain but included a tRNA-utilizing enzyme (tRUE) belonging to the leucyl/phenylalanyl (L/F) transferase family. This system was predicted to direct the synthesis of a novel SPA, which we named livipeptin. Using evolutionary genome mining approaches, here, we confirm the presence of L/F transferase tRUEs within the genomes of diverse Streptomyces and related organisms, including fusions with the anticipated C-minus NRPS-like protein. We then demonstrate genetic functional cooperation between the identified L/F-transferase divergent tRUE homolog with the C-minus NRPS, leading to the synthesis of a metabolic fraction with protease inhibitory activity. Semisynthetic assays in the presence of RNAse revealed that the productive interaction between the tRUE and the C-minus NRPS enzymes is indeed tRNA dependent. We expect our findings to boost the discovery of SPAs, as well as the development of protease-mediated biotechnologies, by exploiting the uncovered genetic basis for synthesizing putative acetyl-leu/phe-arginine protease inhibitors. Furthermore, these results will facilitate the purification and structural elucidation of livipeptin, which has proven difficult to chemically characterize. SIGNIFICANCE The discovery of natural products biosynthetic genes marks a significant advancement in our understanding of these metabolites, for example of their evolution, activity, and biosynthesis, but also opens biotechnological opportunities and knowledge to advance genome mining approaches. We made this possible by uncovering a new biosynthetic pathway in Streptomyces lividans 66 shown to direct the synthesis of a strong protease inhibitor, termed livipeptin, following unprecedented biosynthetic rules and genes. Thus, by shedding light on the genetic mechanisms predicted to govern the production of acetyl-leu/phe-arginine protease inhibitors, including the elusive livipeptin, this study enables novel protease-mediated biotechnologies as well as approaches for discovering protease inhibitors from genome data.
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Affiliation(s)
- César Aguilar
- Evolution of Metabolic Diversity Laboratory, Unidad de Genómica Avanzada (Langebio), Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Irapuato, Guanajuato, CP 36821, México
| | - Karina Verdel-Aranda
- Evolution of Metabolic Diversity Laboratory, Unidad de Genómica Avanzada (Langebio), Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Irapuato, Guanajuato, CP 36821, México
| | - Hilda E Ramos-Aboites
- Evolution of Metabolic Diversity Laboratory, Unidad de Genómica Avanzada (Langebio), Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Irapuato, Guanajuato, CP 36821, México
| | - Cuauhtémoc Licona-Cassani
- Evolution of Metabolic Diversity Laboratory, Unidad de Genómica Avanzada (Langebio), Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Irapuato, Guanajuato, CP 36821, México
| | - Francisco Barona-Gómez
- Evolution of Metabolic Diversity Laboratory, Unidad de Genómica Avanzada (Langebio), Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Irapuato, Guanajuato, CP 36821, México
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8
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Luo Y, Wang J, Wang C, Wang D, Li C, Zhang B, Zhong X, Chen L, Li H, Su H, Zheng Q, Zhu D, Tang H, Guo L. The fecal arsenic excretion, tissue arsenic accumulation, and metabolomics analysis in sub-chronic arsenic-exposed mice after in situ arsenic-induced fecal microbiota transplantation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 854:158583. [PMID: 36084774 DOI: 10.1016/j.scitotenv.2022.158583] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 09/03/2022] [Accepted: 09/03/2022] [Indexed: 06/15/2023]
Abstract
Arsenic can be specifically enriched by rice, and the health hazards caused by high arsenic rice are gradually attracting attention. This study aimed to explore the potential of microbial detoxification via gut microbiome in the treatment of sub-chronic arsenic poisoning. We first exposed mice to high-dose arsenic feed (30 mg/kg, rice arsenic composition) for 60 days to promote arsenic-induced microbes in situ in the gastrointestinal tract, then transplanted their fecal microbiota (FMT) into another batch of healthy recipient mice, and dynamically monitored the microbial colonization by 16S rRNA sequencing and ITS sequencing. The results showed that in situ arsenic-induced fecal microbiome can stably colonized and interact with indigenous microbes in the recipient mice in two weeks, and established a more stable network of gut microbiome. Then, the recipient mice continued to receive high-dose arsenic exposure for 52 days. After above sub-chronic arsenic exposure, compared with the non-FMT group, fecal arsenic excretion, liver and plasma arsenic accumulation were significantly lower (P < 0.05), and that in kidney, hair, and thighbone present no significant differences. Metabolomics of feces- plasma-brain axis were also disturbed, some up-regulated metabolites in feces, plasma, and cerebral cortex may play positive roles for the host. Therefore, microbial detoxification has potential in the treatment of sub-chronic arsenic poisoning. However, gut flora is an extremely complex community with different microorganisms have different arsenic metabolizing abilities, and various microbial metabolites. Coupled with the matrix effects, these factors will have various effects on the efflux and accumulation of arsenic. The definite effects (detoxification or non-detoxification) could be not assured based on the current study, and more systematic and rigorous studies are needed in the future.
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Affiliation(s)
- Yu Luo
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan 523808, China
| | - Jiating Wang
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan 523808, China; Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Chenfei Wang
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan 523808, China; Shenzhen Nanshan Center for Chronic Disease Control, Shenzhen 518000, China
| | - Dongbin Wang
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan 523808, China
| | - Chengji Li
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan 523808, China
| | - Bin Zhang
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan 523808, China
| | - Xiaoting Zhong
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan 523808, China
| | - Linkang Chen
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan 523808, China
| | - Hao Li
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan 523808, China
| | - Hongtian Su
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan 523808, China
| | - Qiuyi Zheng
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan 523808, China
| | - Dajian Zhu
- Department of Surgery, Shunde Women and Children's Hospital (Maternity and Child Healthcare Hospital of Shunde Foshan), Guangdong Medical University, Foshan 528399, China.
| | - Huanwen Tang
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan 523808, China.
| | - Lianxian Guo
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan 523808, China.
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9
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Leitner E, Bozic M, Kienesberger S, Cosic A, Landt O, Högenauer C, Kessler HH. Improved diagnosis of antibiotic-associated haemorrhagic colitis (AAHC) in faecal specimens by a new qualitative real-time PCR assay detecting relevant toxin genes of Klebsiella oxytoca sensu lato. Clin Microbiol Infect 2022; 28:690-694. [PMID: 34582979 DOI: 10.1016/j.cmi.2021.09.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 08/27/2021] [Accepted: 09/15/2021] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Toxin-producing Klebsiella oxytoca causes antibiotic-associated haemorrhagic colitis (AAHC). The disease-relevant cytotoxins tilivalline and tilimycine produced by certain K. oxytoca isolates are encoded by the non-ribosomal peptide synthetase genes A (npsA) and B (npsB). In this study, the new LightMix® Modular kit for the detection of relevant K. oxytoca sensu lato (s.l.) toxin genes was evaluated. METHODS DNA was extracted on the automated EMAG® platform. Amplification was done on the Light Cycler® 480 II instrument. In total, 130 residual faecal specimens collected from patients with antibiotic-associated diarrhoea were studied to determine the clinical sensitivity and specificity. Toxigenic culture served as reference method. RESULTS With the new kit, the limit of detection was 15 CFU/mL for all targets. For the pehX target specific to K. oxytoca s.l., 65 of 130 clinical specimens were positive, while toxin-specific targets (npsA/npsB) were positive in 47 of 130. The npsA/npsB PCR targets showed a clinical sensitivity of 100% (95%CI 80.5-100%) and a specificity of 73.5% (95%CI 64.3-81.3%) with a positive predictive value of 16.5% (95%CI 12.7-21.2%) and a negative predictive value of 100%. CONCLUSION Compared with culture, additional clinical specimens positive for K. oxytoca s.l. were detected with real-time PCR. The specificity of the toxin targets appears moderate due to the inferior sensitivity of the culture-based reference method. Since the developed assay is highly sensitive, it may be used as first-line method to improve the diagnosis of AAHC.
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Affiliation(s)
- Eva Leitner
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Austria.
| | - Michael Bozic
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Austria
| | - Sabine Kienesberger
- Institute of Molecular Biosciences, University of Graz, Austria; BioTechMed-Graz, Austria; Field of Excellence BioHealth, University of Graz, Austria
| | - Amar Cosic
- Institute of Molecular Biosciences, University of Graz, Austria
| | | | - Christoph Högenauer
- BioTechMed-Graz, Austria; Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Austria
| | - Harald H Kessler
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Austria
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10
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Global analysis of biosynthetic gene clusters reveals conserved and unique natural products in entomopathogenic nematode-symbiotic bacteria. Nat Chem 2022; 14:701-712. [PMID: 35469007 PMCID: PMC9177418 DOI: 10.1038/s41557-022-00923-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 02/24/2022] [Indexed: 12/27/2022]
Abstract
Microorganisms contribute to the biology and physiology of eukaryotic hosts and affect other organisms through natural products. Xenorhabdus and Photorhabdus (XP) living in mutualistic symbiosis with entomopathogenic nematodes generate natural products to mediate bacteria–nematode–insect interactions. However, a lack of systematic analysis of the XP biosynthetic gene clusters (BGCs) has limited the understanding of how natural products affect interactions between the organisms. Here we combine pangenome and sequence similarity networks to analyse BGCs from 45 XP strains that cover all sequenced strains in our collection and represent almost all XP taxonomy. The identified 1,000 BGCs belong to 176 families. The most conserved families are denoted by 11 BGC classes. We homologously (over)express the ubiquitous and unique BGCs and identify compounds featuring unusual architectures. The bioactivity evaluation demonstrates that the prevalent compounds are eukaryotic proteasome inhibitors, virulence factors against insects, metallophores and insect immunosuppressants. These findings explain the functional basis of bacterial natural products in this tripartite relationship. ![]()
Entomopathogenic nematodes carrying Xenorhabdus and Photorhabdus bacteria prey on insect larvae in the soil. Now, a comprehensive analysis of the bacterial genome has revealed ubiquitous and unique families of biosynthetic gene clusters. Evaluation of the bioactivity of the natural products expressed by the most prevalent cluster families explains the functional basis of bacterial natural products involved in bacteria–nematode–insect interactions.
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11
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Sun Y, Ding X, Cui Y, Li H, Wang D, Liang H, Liu S, Zhang X, Wang H, Sun T. Positive Effects of Neutrophil Elastase Inhibitor (Sivelestat) on Gut Microbiome and Metabolite Profiles of Septic Rats. Front Cell Infect Microbiol 2022; 12:818391. [PMID: 35372122 PMCID: PMC8965314 DOI: 10.3389/fcimb.2022.818391] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/17/2022] [Indexed: 12/22/2022] Open
Abstract
Background Neutrophil elastase (NE) is associated with sepsis occurrence and progression. We hypothesized that the NE inhibitor Sivelestat might modulate abnormal gut microbiota and metabolites during sepsis. Methods Sixty Sprague-Dawley (SD) rats were randomly divided into sham control (SC), sepsis (CLP), and sepsis+Sivelestat (Sive) groups. The rats’ survival status was monitored for 24 hours postoperatively, and feces were collected for microbiome and non-targeted metabolomics analyses. Results Sivelestat administration significantly improved the survival of septic rats (80% vs 50%, P = 0.047). Microbiome analysis showed that the microbiota composition of rats in the CLP group was significantly disturbed, as potential pathogens such as Escherichia-Shigella and Gammaproteobacteria became dominant, and the beneficial microbiota represented by Lactobacillus decreased. These changes were reversed in Sive group, and the overall microbial status was restored to a similar composition to SC group. Differential analysis identified 36 differential operational taxonomic units and 11 metabolites between the Sive and CLP groups, such as 6-Aminopenicillanic acid, gamma-Glutamyl-leucine, and cortisone (variable importance in projection>1and P<0.05). These discriminatory metabolites were highly correlated with each other and mainly involved in the phenylalanine, tyrosine, and tryptophan biosynthesis pathways. Integrated microbiome and metabolome analyses found that almost all Sivelestat-modulated microbes were associated with differential metabolites (P < 0.05), such as Lactobacillus and some amino acids, suggesting that the Sivelestat-induced metabolic profile differences were in part due to its influence on the gut microbiome. Conclusion Sivelestat administration in septic rats improved survival, gut microbiota composition and associated metabolites, which could provide new options for sepsis treatment.
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12
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Greimel TM, Stampfer L, Leitner E, Kienesberger S, Zechner EL, Bozic M, Wagner GE, Unterhauser K, Kitsera M, Hauer AC, Gorkiewicz G, Wurm P, Valitutti F, Högenauer C, Hoffmann KM. Toxin-Producing Klebsiella oxytoca in Healthy Infants: Commensal or Pathobiont? J Pediatr Gastroenterol Nutr 2022; 74:e1-e7. [PMID: 34520403 DOI: 10.1097/mpg.0000000000003299] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Klebsiella oxytoca is a gastrointestinal pathobiont with the potential to produce the toxins tilivalline and tilimycin, which cause antibiotic-associated hemorrhagic colitis. Overgrowth of toxigenic K oxytoca has recently been implicated in necrotizing enterocolitis. K oxytoca colonizes 2-9% of healthy adults, however, there is no systematic data on colonization in healthy children. We investigated K oxytoca colonization and its toxigenic properties in healthy infants. METHODS We sampled stool of healthy infants and determined K oxytoca colonization using stool culture and PCR (pehX). Toxin in stool was measured with HPLC/high-resolution mass spectrometry. K oxytoca isolates were typed using multi-locus sequence typing (MLST) and K oxytoca toxin PCR (npsA/B). Cytotoxin production of isolates was analyzed by MTT assay. RESULTS K oxytoca was detected in 30 of 61 infants (49%) using stool culture and in 45 of 61 (73%) using PCR (pehX). Toxin marker PCR (npsA/B) was positive in 66% of stool samples positive for K oxytoca PCR. Stool toxin levels were too low for quantitation but traces of tilivalline were detected. Contrarily, 49% of K oxytoca isolates demonstrated toxicity in the MTT assay. MLST revealed 36 distinct sequence types affiliated with all known K oxytoca sequence type clusters (A, B1 and B2). CONCLUSIONS More than 70% of healthy infants were colonized with K oxytoca. Toxin quantities in stool of colonized healthy infants were below detection level, yet half of the isolates produced toxin in vitro demonstrating their pathobiont potential. The high occurrence of toxigenic K oxytoca in healthy infants has to be considered for future disease association studies.
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Affiliation(s)
- Theresa M Greimel
- Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine
| | - Laura Stampfer
- Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine
| | - Eva Leitner
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz
| | - Sabine Kienesberger
- Institute of Molecular Biosciences, University of Graz
- BioTechMed-Graz
- Field of Excellence BioHealth - University of Graz, Graz
| | - Ellen L Zechner
- Institute of Molecular Biosciences, University of Graz
- BioTechMed-Graz
- Field of Excellence BioHealth - University of Graz, Graz
| | - Michael Bozic
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz
| | - Gabriel E Wagner
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz
| | | | | | - Almuthe C Hauer
- Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine
| | - Gregor Gorkiewicz
- Institute of Pathology, Medical University of Graz, Austria
- BioTechMed-Graz
| | - Philipp Wurm
- Institute of Pathology, Medical University of Graz, Austria
| | | | - Christoph Högenauer
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz
- BioTechMed-Graz
| | - Karl Martin Hoffmann
- Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine
- Kinderärzte Zentrum Graz-Raaba, Raaba-Grambach, Austria
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13
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Li JH, Cho W, Hamchand R, Oh J, Crawford JM. A Conserved Nonribosomal Peptide Synthetase in Xenorhabdus bovienii Produces Citrulline-Functionalized Lipopeptides. JOURNAL OF NATURAL PRODUCTS 2021; 84:2692-2699. [PMID: 34581573 PMCID: PMC9970011 DOI: 10.1021/acs.jnatprod.1c00573] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The entomopathogenic bacterium Xenorhabdus bovienii exists in a mutualistic relationship with nematodes of the genus Steinernema. Free-living infective juveniles of Steinernema prey on insect larvae and regurgitate X. bovienii within the hemocoel of a host larva. X. bovienii subsequently produces a complex array of specialized metabolites and effector proteins that kill the insect and regulate various aspects of the trilateral symbiosis. While Xenorhabdus species are rich producers of secondary metabolites, many of their biosynthetic gene clusters remain uncharacterized. Here, we describe a nonribosomal peptide synthetase (NRPS) identified through comparative genomics analysis that is widely conserved in Xenorhabdus species. Heterologous expression of this NRPS gene from X. bovienii in E. coli led to the discovery of a family of lipo-tripeptides that chromatographically appear as pairs, containing either a C-terminal carboxylic acid or carboxamide. Coexpression of the NRPS with the leupeptin protease inhibitor pathway enhanced production, facilitating isolation and characterization efforts. The new lipo-tripeptides were also detected in wild-type X. bovienii cultures. These metabolites, termed bovienimides, share an uncommon C-terminal d-citrulline residue. The NRPS lacked a dedicated chain termination domain, resulting in product diversification and release from the assembly line through reactions with ammonia, water, or exogenous alcohols.
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Affiliation(s)
- Jhe-Hao Li
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
- Institute of Biomolecular Design and Discovery, Yale University, West Haven, Connecticut 06516, United States
| | - Wooyoung Cho
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
- Institute of Biomolecular Design and Discovery, Yale University, West Haven, Connecticut 06516, United States
| | - Randy Hamchand
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
- Institute of Biomolecular Design and Discovery, Yale University, West Haven, Connecticut 06516, United States
| | - Joonseok Oh
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
- Institute of Biomolecular Design and Discovery, Yale University, West Haven, Connecticut 06516, United States
| | - Jason M Crawford
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
- Institute of Biomolecular Design and Discovery, Yale University, West Haven, Connecticut 06516, United States
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut 06536, United States
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14
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Abstract
The human microbiome encodes a second genome that dwarfs the genetic capacity of the host. Microbiota-derived small molecules can directly target human cells and their receptors or indirectly modulate host responses through functional interactions with other microbes in their ecological niche. Their biochemical complexity has profound implications for nutrition, immune system development, disease progression, and drug metabolism, as well as the variation in these processes that exists between individuals. While the species composition of the human microbiome has been deeply explored, detailed mechanistic studies linking specific microbial molecules to host phenotypes are still nascent. In this review, we discuss challenges in decoding these interaction networks, which require interdisciplinary approaches that combine chemical biology, microbiology, immunology, genetics, analytical chemistry, bioinformatics, and synthetic biology. We highlight important classes of microbiota-derived small molecules and notable examples. An understanding of these molecular mechanisms is central to realizing the potential of precision microbiome editing in health, disease, and therapeutic responses.
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Affiliation(s)
- Emilee E Shine
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut 06536, USA; .,Chemical Biology Institute, Yale University, West Haven, Connecticut 06516, USA.,Current affiliation: Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
| | - Jason M Crawford
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut 06536, USA; .,Chemical Biology Institute, Yale University, West Haven, Connecticut 06516, USA.,Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA
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15
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Cosic A, Leitner E, Petternel C, Galler H, Reinthaler FF, Herzog-Obereder KA, Tatscher E, Raffl S, Feierl G, Högenauer C, Zechner EL, Kienesberger S. Variation in Accessory Genes Within the Klebsiella oxytoca Species Complex Delineates Monophyletic Members and Simplifies Coherent Genotyping. Front Microbiol 2021; 12:692453. [PMID: 34276625 PMCID: PMC8283571 DOI: 10.3389/fmicb.2021.692453] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 05/28/2021] [Indexed: 02/03/2023] Open
Abstract
Members of the Klebsiella oxytoca species complex (KoSC) are emerging human pathogens causing infections of increasing significance especially in healthcare settings. KoSC strains are affiliated with distinct phylogroups based on genetic variation at the beta-lactamase gene (bla OXY) and it has been proposed that each major phylogroup represents a unique species. However, since the typing methods applied in clinical settings cannot differentiate every species within the complex, existing clinical, epidemiological and DNA sequence data is frequently misclassified. Here we systematically examined the phylogenetic relationship of KoSC strains to evaluate robustness of existing typing methods and to provide a simple typing strategy for KoSC members that cannot be differentiated biochemically. Initial analysis of a collection of K. oxytoca, K. michiganensis, K. pasteurii, and K. grimontii strains of environmental origin showed robust correlation of core phylogeny and blaOXY grouping. Moreover, we identified species-specific accessory gene loci for these strains. Extension of species correlation using database entries initially failed. However, assessment of average nucleotide identities (ANI) and phylogenetic validations showed that nearly one third of isolates in public databases have been misidentified. Reclassification resulted in a robust reference strain set for reliable species identification of new isolates or for retyping of strains previously analyzed by multi-locus sequence typing (MLST). Finally, we show convergence of ANI, core gene phylogeny, and accessory gene content for available KoSC genomes. We conclude that also the monophyletic members K. oxytoca, K. michiganensis, K. pasteurii and K. grimontii can be simply differentiated by a PCR strategy targeting bla OXY and accessory genes defined here.
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Affiliation(s)
- Amar Cosic
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Eva Leitner
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Christian Petternel
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Herbert Galler
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Franz F. Reinthaler
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Kathrin A. Herzog-Obereder
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Elisabeth Tatscher
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Sandra Raffl
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Gebhard Feierl
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Christoph Högenauer
- BioTechMed-Graz, Graz, Austria
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Ellen L. Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
| | - Sabine Kienesberger
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- *Correspondence: Sabine Kienesberger,
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