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Chandrakasan G, García-Trejo JF, Feregrino-Pérez AA, Aguirre-Becerra H, García ER, Nieto-Ramírez MI. Preliminary Screening on Antibacterial Crude Secondary Metabolites Extracted from Bacterial Symbionts and Identification of Functional Bioactive Compounds by FTIR, HPLC and Gas Chromatography-Mass Spectrometry. Molecules 2024; 29:2914. [PMID: 38930979 PMCID: PMC11206551 DOI: 10.3390/molecules29122914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/02/2024] [Accepted: 06/06/2024] [Indexed: 06/28/2024] Open
Abstract
Secondary metabolites, bioactive compounds produced by living organisms, can unveil symbiotic relationships in nature. In this study, soilborne entomopathogenic nematodes associated with symbiotic bacteria (Xenorhabdus stockiae and Photorhabdus luminescens) were extracted from solvent supernatant containing secondary metabolites, demonstrating significant inhibitory effects against E. coli, S. aureus, B. subtilus, P. mirabilis, E. faecalis, and P. stutzeri. The characterization of these secondary metabolites by Fourier transforms infrared spectroscopy revealed amine groups of proteins, hydroxyl and carboxyl groups of polyphenols, hydroxyl groups of polysaccharides, and carboxyl groups of organic acids. Furthermore, the obtained crude extracts were analyzed by high-performance liquid chromatography for the basic identification of potential bioactive peptides. Gas chromatography-mass spectrometry analysis of ethyl acetate extracts from Xenorhabdus stockiae identified major compounds including nonanoic acid derivatives, proline, paromycin, octodecanal derivatives, trioxa-5-aza-1-silabicyclo, 4-octadecenal, methyl ester, oleic acid, and 1,2-benzenedicarboxylicacid. Additional extraction from Photorhabdus luminescens yielded functional compounds such as indole-3-acetic acid, phthalic acid, 1-tetradecanol, nemorosonol, 1-eicosanol, and unsaturated fatty acids. These findings support the potential development of novel natural antimicrobial agents for future pathogen suppression.
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Affiliation(s)
- Gobinath Chandrakasan
- División de Estudios de Posgrado, Facultad de Ingeniería, Universidad Autónoma de Querétaro, Santiago de Querétaro 76010, Querétaro, Mexico; (A.A.F.-P.); (H.A.-B.); (E.R.G.); (M.I.N.-R.)
| | - Juan Fernando García-Trejo
- División de Estudios de Posgrado, Facultad de Ingeniería, Universidad Autónoma de Querétaro, Santiago de Querétaro 76010, Querétaro, Mexico; (A.A.F.-P.); (H.A.-B.); (E.R.G.); (M.I.N.-R.)
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2
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Hadchity L, Houard J, Lanois A, Payelleville A, Nassar F, Gualtieri M, Givaudan A, Abi Khattar Z. The AcrAB efflux pump confers self-resistance to stilbenes in Photorhabdus laumondii. Res Microbiol 2023; 174:104081. [PMID: 37196776 DOI: 10.1016/j.resmic.2023.104081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 05/07/2023] [Accepted: 05/10/2023] [Indexed: 05/19/2023]
Abstract
The Resistance-nodulation-division (RND)-type AcrAB-TolC efflux pump contributes to multidrug resistance in Gram-negative bacteria. Recently, the bacterium Photorhabdus laumondii TT01 has emerged as a goldmine for novel anti-infective drug discovery. Outside plants, Photorhabdus is the only Gram-negative known to produce stilbene-derivatives including 3,5-dihydroxy-4-ethyl-trans-stilbene and 3,5-dihydroxy-4-isopropyl-trans-stilbene (IPS). IPS is a bioactive polyketide which received considerable attention, mainly because of its antimicrobial properties, and is currently in late-stage clinical development as a topical treatment for psoriasis and dermatitis. To date, little is known about how Photorhabdus survives in the presence of stilbenes. We combined genetic and biochemical approaches to assess whether AcrAB efflux pump exports stilbenes in P. laumondii. We demonstrated that the wild-type (WT) exerts an antagonistic activity against its derivative ΔacrA mutant, and that is able to outcompete it in a dual-strain co-culture assay. The ΔacrA mutant also showed high sensitivity to 3,5-dihydroxy-4-ethyl-trans-stilbene and IPS as well as decreased IPS concentrations in its supernatant comparing to the WT. We report here a mechanism of self-resistance against stilbene derivatives of P. laumondii TT01, which enables these bacteria to survive under high concentrations of stilbenes by extruding them out via the AcrAB efflux pump.
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Affiliation(s)
- Linda Hadchity
- Laboratory of Georesources, Geosciences and Environment (L2GE), Microbiology/Tox-Ecotoxicology Team, Faculty of Sciences 2, Lebanese University, P.O.Box 90656, Jdeidet El-Metn, Lebanon; DGIMI, Université Montpellier, INRAE, Montpellier, France.
| | | | - Anne Lanois
- DGIMI, Université Montpellier, INRAE, Montpellier, France.
| | - Amaury Payelleville
- Cellular and Molecular Microbiology, Faculté des Sciences, Université Libre de Bruxelles, Gosselies, Belgium.
| | - Fida Nassar
- Laboratory of Georesources, Geosciences and Environment (L2GE), Microbiology/Tox-Ecotoxicology Team, Faculty of Sciences 2, Lebanese University, P.O.Box 90656, Jdeidet El-Metn, Lebanon.
| | | | - Alain Givaudan
- DGIMI, Université Montpellier, INRAE, Montpellier, France.
| | - Ziad Abi Khattar
- Laboratory of Georesources, Geosciences and Environment (L2GE), Microbiology/Tox-Ecotoxicology Team, Faculty of Sciences 2, Lebanese University, P.O.Box 90656, Jdeidet El-Metn, Lebanon.
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3
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Vincent SA, Ebertz A, Spanu PD, Devlin PF. Salicylic Acid-Mediated Disturbance Increases Bacterial Diversity in the Phyllosphere but Is Overcome by a Dominant Core Community. Front Microbiol 2022; 13:809940. [PMID: 35283825 PMCID: PMC8908428 DOI: 10.3389/fmicb.2022.809940] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/18/2022] [Indexed: 11/13/2022] Open
Abstract
Plant microbiomes and immune responses have coevolved through history, and this applies just as much to the phyllosphere microbiome and defense phytohormone signaling. When in homeostasis, the phyllosphere microbiome confers benefits to its host. However, the phyllosphere is also dynamic and subject to stochastic events that can modulate community assembly. Investigations into the impact of defense phytohormone signaling on the microbiome have so far been limited to culture-dependent studies; or focused on the rhizosphere. In this study, the impact of the foliar phytohormone salicylic acid (SA) on the structure and composition of the phyllosphere microbiome was investigated. 16S rRNA amplicons were sequenced from aerial tissues of two Arabidopsis mutants that exhibit elevated SA signaling through different mechanisms. SA signaling was shown to increase community diversity and to result in the colonization of rare, satellite taxa in the phyllosphere. However, a stable core community remained in high abundance. Therefore, we propose that SA signaling acts as a source of intermediate disturbance in the phyllosphere. Predictive metagenomics revealed that the SA-mediated microbiome was enriched for antibiotic biosynthesis and the degradation of a diverse range of xenobiotics. Core taxa were predicted to be more motile, biofilm-forming and were enriched for traits associated with microbe-microbe communication; offering potential mechanistic explanation of their success despite SA-mediated phyllospheric disturbance.
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Affiliation(s)
- Stacey A Vincent
- Department of Biological Sciences, Royal Holloway, University of London, Egham, United Kingdom
| | - Andreas Ebertz
- Department of Biological Sciences, Royal Holloway, University of London, Egham, United Kingdom
| | - Pietro D Spanu
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Paul F Devlin
- Department of Biological Sciences, Royal Holloway, University of London, Egham, United Kingdom
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4
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Kassam R, Yadav J, Chawla G, Kundu A, Hada A, Jaiswal N, Bollinedi H, Kamil D, Devi P, Rao U. Identification, Characterization, and Evaluation of Nematophagous Fungal Species of Arthrobotrys and Tolypocladium for the Management of Meloidogyne incognita. Front Microbiol 2021; 12:790223. [PMID: 34956156 PMCID: PMC8702965 DOI: 10.3389/fmicb.2021.790223] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 11/10/2021] [Indexed: 11/13/2022] Open
Abstract
Root-knot nematodes belonging to the genus Meloidogyne are agriculturally important pests, and biocontrol strategies offer safer alternatives for their management. In the present study, two fungal species from Indian soils were identified as Arthrobotrys thaumasia and Tolypocladium cylindrosporum based on morphological characteristics and further confirmed using molecular markers. In vitro evaluation of A. thaumasia against M. incognita and Caenorhabditis elegans showed 82 and 73% parasitism, respectively, whereas T. cylindrosporum gave 65.2 and 57.7% parasitism, respectively. Similarly, culture filtrates of A. thaumasia caused 57.7 and 53.7% mortality of M. incognita and C. elegans, respectively, whereas T. cylindrosporum caused higher mortality of 87.3 and 64%, respectively. Besides, greenhouse evaluation of both fungi against M. incognita infecting tomato significantly reduced nematode disease burden reflecting parasitic success measured as the total number of galls, egg masses, eggs per egg mass, and derived nematode multiplication factor. Application of A. thaumasia and T. cylindrosporum reduced nematode multiplication factor by 80 and 95%, respectively, compared with control. General metabolite profiling of tested fungi using gas chromatography–mass spectrometry and ultra-performance liquid chromatography–quadrupole/time of flight mass spectrometry reported for the first time here showed presence of various volatile and non-volatile compounds with nematicidal activity, viz., trimethyl-heptadiene, methyl-hexadecanol, dodecadienal, decane, terpendole E, dodecane, acetamido-6-anthraquinone, and hexadecanol. Also, other compounds such as undecane, dibutyl-disulfide, octadecenal, paganin, talathermophilin, dactylarin, tolypyridone A, tolypyridone B, pyridoxatin, and destruxin were identified, reported in the literature to possess antibacterial, antifungal, and insecticidal properties. This is the first report of the occurrence of both fungi from India and pioneer demonstration of T. cylindrosporum for root-knot nematode management.
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Affiliation(s)
- Rami Kassam
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Jyoti Yadav
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Gautam Chawla
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Aditi Kundu
- Division of Agricultural Chemicals, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Alkesh Hada
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Nisha Jaiswal
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Haritha Bollinedi
- Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Deeba Kamil
- Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Prameela Devi
- Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Uma Rao
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, India
- *Correspondence: Uma Rao, ; orcid.org/0000-0002-1233-2921
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Papadopoulou EA, Angelis A, Antoniadi L, Aliferis KA, Skaltsounis AL. Discovering the Next-Generation Plant Protection Products: A Proof-of-Concept via the Isolation and Bioactivity Assessment of the Olive Tree Endophyte Bacillus sp. PTA13 Lipopeptides. Metabolites 2021; 11:metabo11120833. [PMID: 34940591 PMCID: PMC8705366 DOI: 10.3390/metabo11120833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/24/2021] [Accepted: 11/30/2021] [Indexed: 11/16/2022] Open
Abstract
Endophytic microorganisms (EMs) have recently attracted interest for applications in plant protection, mainly due to their bioactive compound-producing capacity. Therefore, we underwent the task of isolating olive tree EMs and investigating their bioactivity against the devastating pathogen Colletotrichum acutatum. Several EMs were isolated; however, the Bacillus sp. PTA13 isolate exhibited the highest toxicity to the phytopathogen. Bacteria of the genus Bacillus exhibit superior bioactive metabolite-producing capacity, with the lipopeptides (LPs) of surfactin, iturin, and fengycin groups being the most studied. A total LP extract and several fractions were obtained, and their bioactivity was assessed against C. acutatum strains. LPs of the major surfactin, iturin, and fengycin groups and the minor gageotetrin and bacilotetrin groups were annotated. The results confirmed the bioactivity of the major LPs, with fengycins being the most fungitoxic. Interestingly, the minor LP fraction exhibited selective toxicity to the fungicide-resistant C. acutatum isolate, an observation that highlights the significance of our approach to comprehensively mine the total LP extract. This work represents a proof of concept of the exploitation of EMs in customized olive tree plant protection and aligns well with strategies that focus on the sustainability and safety of food production via the development of next-generation plant protection products.
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Affiliation(s)
- Evgenia-Anna Papadopoulou
- Laboratory of Pesticide Science, Department of Crop Science, Agricultural University of Athens, 11855 Athens, Greece;
- Department of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy, University of Athens, 15771 Athens, Greece; (A.A.); (L.A.)
| | - Apostolis Angelis
- Department of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy, University of Athens, 15771 Athens, Greece; (A.A.); (L.A.)
| | - Lemonia Antoniadi
- Department of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy, University of Athens, 15771 Athens, Greece; (A.A.); (L.A.)
| | - Konstantinos A. Aliferis
- Laboratory of Pesticide Science, Department of Crop Science, Agricultural University of Athens, 11855 Athens, Greece;
- Department of Plant Science, McGill University, Macdonald Campus, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada
- Correspondence: (K.A.A.); (A.-L.S.); Tel.: +30-210-5294541 (K.A.A.); +30-210-7274598 (A.-L.S.)
| | - Alexios-Leandros Skaltsounis
- Department of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy, University of Athens, 15771 Athens, Greece; (A.A.); (L.A.)
- Correspondence: (K.A.A.); (A.-L.S.); Tel.: +30-210-5294541 (K.A.A.); +30-210-7274598 (A.-L.S.)
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6
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Hill V, Kuhnert P, Erb M, Machado RAR. Identification of Photorhabdus symbionts by MALDI-TOF MS. MICROBIOLOGY-SGM 2021; 166:522-530. [PMID: 32301690 DOI: 10.1099/mic.0.000905] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Species of the bacterial genus Photorhabus live in a symbiotic relationship with Heterorhabditis entomopathogenic nematodes. Besides their use as biological control agents against agricultural pests, some Photorhabdus species are also a source of natural products and are of medical interest due to their ability to cause tissue infections and subcutaneous lesions in humans. Given the diversity of Photorhabdus species, rapid and reliable methods to resolve this genus to the species level are needed. In this study, we evaluated the potential of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the identification of Photorhabdus species. To this end, we established a collection of 54 isolates consisting of type strains and multiple field strains that belong to each of the validly described species and subspecies of this genus. Reference spectra for the strains were generated and used to complement a currently available database. The extended reference database was then used for identification based on the direct transfer sample preparation method and the protein fingerprint of single colonies. High-level discrimination of distantly related species was observed. However, lower discrimination was observed with some of the most closely related species and subspecies. Our results therefore suggest that MALDI-TOF MS can be used to correctly identify Photorhabdus strains at the genus and species level, but has limited resolution power for closely related species and subspecies. Our study demonstrates the suitability and limitations of MALDI-TOF-based identification methods for assessment of the taxonomic position and identification of Photorhabdus isolates.
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Affiliation(s)
- Virginia Hill
- Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Switzerland.,Institute of Plant Sciences, University of Bern, Switzerland
| | - Peter Kuhnert
- Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Switzerland
| | - Matthias Erb
- Institute of Plant Sciences, University of Bern, Switzerland
| | - Ricardo A R Machado
- Experimental Biology Research Group, University of Neuchatel, Switzerland.,Institute of Plant Sciences, University of Bern, Switzerland
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Tilocca B, Soggiu A, Greco V, Sacchini F, Garofolo G, Paci V, Bonizzi L, Urbani A, Tittarelli M, Roncada P. Comparative proteomics of Brucella melitensis is a useful toolbox for developing prophylactic interventions in a One-Health context. One Health 2021; 13:100253. [PMID: 33997237 PMCID: PMC8100217 DOI: 10.1016/j.onehlt.2021.100253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 11/28/2022] Open
Abstract
Brucellosis caused by Brucella melitensis is a zoonosis frequently reported in the Mediterranean and Middle-East regions and responsible for important economic losses and reduced animal welfare. To date, current strategies applied to control or eradicate the disease relies on diagnostic tests that suffer from limited specificity in non-vaccinated animals; while prophylactic measures, when applied, use a live attenuated bacterial strain characterized by residual virulence on adult pregnant animals and difficulties in distinguishing vaccinated from infected animals. To overcome these issues, studies are desired to elucidate the bacterial biology and the pathogenetic mechanisms of both the vaccinal strain and the pathogenic strains. Proteomics has a potential in tackling issues of One-Health concern; here, we employed label-free shotgun proteomics to investigate the protein repertoire of the vaccinal strain B. melitensis Rev.1 and compare it with the proteome of the Brucella melitensis 16 M, a reference strain representative of B. melitensis field strains. Comparative proteomics profiling underlines common and diverging traits between the two strains. Common features suggest the potential biochemical routes responsible for the residual virulence of the vaccinal strain, whilst the diverging traits are suggestive biochemical signatures to be further investigated to provide an optimized diagnostic capable of discriminating the vaccinated from infected animals. The data presented in this study are openly available in PRIDE data repository at https://www.ebi.ac.uk/pride/, reference number PXD022472.
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Affiliation(s)
- Bruno Tilocca
- Department of Health Sciences, University "Magna Græcia" of Catanzaro, viale Europa, 88100 Catanzaro, Italy
| | - Alessio Soggiu
- Department of Biomedical, Surgical and Dental Sciences- One Health Unit, University of Milano, via Celoria 10, 20133 Milano, Italy
| | - Viviana Greco
- Department of Basic Biotechnological Sciences, Intensivological and Perioperative Clinics, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy.,Fondazione Policlinico Universitario Agostino Gemelli, Largo A. Gemelli, 8-00168 Rome, Italy
| | - Flavio Sacchini
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Centro di Referenza Nazionale per le brucellosi animali, Via Campo Boario 1, 64100 Teramo, Italy
| | - Giuliano Garofolo
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Centro di Referenza Nazionale per le brucellosi animali, Via Campo Boario 1, 64100 Teramo, Italy
| | - Valentina Paci
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Centro di Referenza Nazionale per le brucellosi animali, Via Campo Boario 1, 64100 Teramo, Italy
| | - Luigi Bonizzi
- Department of Biomedical, Surgical and Dental Sciences- One Health Unit, University of Milano, via Celoria 10, 20133 Milano, Italy
| | - Andrea Urbani
- Department of Basic Biotechnological Sciences, Intensivological and Perioperative Clinics, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy.,Fondazione Policlinico Universitario Agostino Gemelli, Largo A. Gemelli, 8-00168 Rome, Italy
| | - Manuela Tittarelli
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Centro di Referenza Nazionale per le brucellosi animali, Via Campo Boario 1, 64100 Teramo, Italy
| | - Paola Roncada
- Department of Health Sciences, University "Magna Græcia" of Catanzaro, viale Europa, 88100 Catanzaro, Italy
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8
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Eckstein S, Dominelli N, Brachmann A, Heermann R. Phenotypic Heterogeneity of the Insect Pathogen Photorhabdus luminescens: Insights into the Fate of Secondary Cells. Appl Environ Microbiol 2019; 85:e01910-19. [PMID: 31492667 PMCID: PMC6821960 DOI: 10.1128/aem.01910-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 08/27/2019] [Indexed: 11/20/2022] Open
Abstract
Photorhabdus luminescens is a Gram-negative bacterium that lives in symbiosis with soil nematodes and is simultaneously highly pathogenic toward insects. The bacteria exist in two phenotypically different forms, designated primary (1°) and secondary (2°) cells. Yet unknown environmental stimuli as well as global stress conditions induce phenotypic switching of up to 50% of 1° cells to 2° cells. An important difference between the two phenotypic forms is that 2° cells are unable to live in symbiosis with nematodes and are therefore believed to remain in the soil after a successful infection cycle. In this work, we performed a transcriptomic analysis to highlight and better understand the role of 2° cells and their putative ability to adapt to living in soil. We could confirm that the major phenotypic differences between the two cell forms are mediated at the transcriptional level as the corresponding genes were downregulated in 2° cells. Furthermore, 2° cells seem to be adapted to another environment as we found several differentially expressed genes involved in the cells' metabolism, motility, and chemotaxis as well as stress resistance, which are either up- or downregulated in 2° cells. As 2° cells, in contrast to 1° cells, chemotactically responded to different attractants, including plant root exudates, there is evidence for the rhizosphere being an alternative environment for the 2° cells. Since P. luminescens is biotechnologically used as a bio-insecticide, investigation of a putative interaction of 2° cells with plants is also of great interest for agriculture.IMPORTANCE The biological function and the fate of P. luminescens 2° cells were unclear. Here, we performed comparative transcriptomics of P. luminescens 1° and 2° cultures and found several genes, not only those coding for known phenotypic differences of the two cell forms, that are up- or downregulated in 2° cells compared to levels in 1° cells. Our results suggest that when 1° cells convert to 2° cells, they drastically change their way of life. Thus, 2° cells could easily adapt to an alternative environment such as the rhizosphere and live freely, independent of a host, putatively utilizing plant-derived compounds as nutrient sources. Since 2° cells are not able to reassociate with the nematodes, an alternative lifestyle in the rhizosphere would be conceivable.
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Affiliation(s)
- Simone Eckstein
- Institut für Molekulare Physiologie, Mikrobiologie und Weinforschung, Johannes-Gutenberg-Universität Mainz, Mainz, Germany
- Biozentrum, Bereich Mikrobiologie, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Nazzareno Dominelli
- Institut für Molekulare Physiologie, Mikrobiologie und Weinforschung, Johannes-Gutenberg-Universität Mainz, Mainz, Germany
| | - Andreas Brachmann
- Biozentrum, Bereich Genetik, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Ralf Heermann
- Institut für Molekulare Physiologie, Mikrobiologie und Weinforschung, Johannes-Gutenberg-Universität Mainz, Mainz, Germany
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9
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Shi YM, Bode HB. Chemical language and warfare of bacterial natural products in bacteria-nematode-insect interactions. Nat Prod Rep 2019; 35:309-335. [PMID: 29359226 DOI: 10.1039/c7np00054e] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Covering: up to November 2017 Organismic interaction is one of the fundamental principles for survival in any ecosystem. Today, numerous examples show the interaction between microorganisms like bacteria and higher eukaryotes that can be anything between mutualistic to parasitic/pathogenic symbioses. There is also increasing evidence that microorganisms are used by higher eukaryotes not only for the supply of essential factors like vitamins but also as biological weapons to protect themselves or to kill other organisms. Excellent examples for such systems are entomopathogenic nematodes of the genera Heterorhabditis and Steinernema that live in mutualistic symbiosis with bacteria of the genera Photorhabdus and Xenorhabdus, respectively. Although these systems have been used successfully in organic farming on an industrial scale, it was only shown during the last 15 years that several different natural products (NPs) produced by the bacteria play key roles in the complex life cycle of the bacterial symbionts, the nematode host and the insect prey that is killed by and provides nutrients for the nematode-bacteria pair. Since the bacteria can switch from mutualistic to pathogenic lifestyle, interacting with two different types of higher eukaryotes, and since the full system with all players can be established in the lab, they are promising model systems to elucidate the natural function of microbial NPs. This review summarizes the current knowledge as well as open questions for NPs from Photorhabdus and Xenorhabdus and tries to assign their roles in the tritrophic relationship.
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Affiliation(s)
- Yi-Ming Shi
- Merck-Stiftungsprofessur für Molekulare Biotechnologie, Fachbereich Biowissenschaften, Goethe Universität Frankfurt, Frankfurt am Main 60438, Germany
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10
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Perez CE, Park HB, Crawford JM. Functional Characterization of a Condensation Domain That Links Nonribosomal Peptide and Pteridine Biosynthetic Machineries in Photorhabdus luminescens. Biochemistry 2018; 57:354-361. [PMID: 29111689 DOI: 10.1021/acs.biochem.7b00863] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Nonribosomal peptide synthetases (NRPSs) produce a wide variety of biologically important small molecules. NRPSs can interface with other enzymes to form hybrid biosynthetic systems that expand the structural and functional diversity of their products. The pepteridines are metabolites encoded by an unprecedented pteridine-NRPS-type hybrid biosynthetic gene cluster in Photorhabdus luminescens, but how the distinct enzymatic systems interface to produce these molecules has not been examined at the biochemical level. By an unknown mechanism, the genetic locus can also affect the regulation of other enzymes involved in autoinducer and secondary metabolite biosynthesis. Here, through in vitro protein biochemical assays, we demonstrate that an atypical NRPS condensation (C) domain present in the pathway condenses acyl units derived from α-keto acids onto a free 5,6,7,8-tetrahydropterin core, producing the tertiary cis-amide-containing pepteridines. Solution studies of the chemically synthesized molecules led to the same amide regiochemistries that were observed in the natural products. The biochemical transformations mediated by the C domain destroy the radical scavenging activity of its redox active tetrahydropterin substrate. Secondary metabolite analyses revealed that the pepteridine locus affects select metabolic pathways associated with quorum sensing, antibiosis, and symbiosis. Taken together, the results suggest that the pathway likely regulates cellular redox and specialized metabolic pathways through engagement with the citric acid cycle.
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Affiliation(s)
- Corey E Perez
- Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States.,Chemical Biology Institute, Yale University , West Haven, Connecticut 06516, United States
| | - Hyun Bong Park
- Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States.,Chemical Biology Institute, Yale University , West Haven, Connecticut 06516, United States
| | - Jason M Crawford
- Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States.,Chemical Biology Institute, Yale University , West Haven, Connecticut 06516, United States.,Department of Microbial Pathogenesis, Yale School of Medicine , New Haven, Connecticut 06510, United States
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11
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Giblin-Davis RM. Who has 'Dibs!' on a dead rhinoceros beetle? Environ Microbiol 2017; 19:2115-2116. [PMID: 28447387 DOI: 10.1111/1462-2920.13772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 04/19/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Robin M Giblin-Davis
- Fort Lauderdale Research and Education Center, University of Florida/IFAS, 3205 College Avenue, Davie, FL, 33314, USA
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12
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Valverde C. Who's the boss here? The post‐transcriptional global regulator
H
fq takes over control of secondary metabolite production in the nematode symbiont
P
hotorhabdus luminiscens. Environ Microbiol 2017; 19:21-24. [DOI: 10.1111/1462-2920.13635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Claudio Valverde
- Departamento de Ciencia y Tecnología, LBMIBSUniversidad Nacional de Quilmes – CONICETBernalB1876BXD Argentina
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13
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Heinrich AK, Glaeser A, Tobias NJ, Heermann R, Bode HB. Heterogeneous regulation of bacterial natural product biosynthesis via a novel transcription factor. Heliyon 2016; 2:e00197. [PMID: 27957552 PMCID: PMC5133734 DOI: 10.1016/j.heliyon.2016.e00197] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 10/19/2016] [Accepted: 11/11/2016] [Indexed: 11/25/2022] Open
Abstract
Biological diversity arises among genetically equal subpopulations in the same environment, a phenomenon called phenotypic heterogeneity. The life cycle of the enteric bacterium Photorhabdus luminescens involves a symbiotic interaction with nematodes as well as a pathogenic association with insect larvae. P. luminescens exists in two distinct phenotypic forms designated as primary (1°) and secondary (2°). In contrast to 1° cells, 2° cells are non-pigmented due to the absence of natural compounds, especially anthraquinones (AQs). We identified a novel type of transcriptional regulator, AntJ, which activates expression of the antA-I operon responsible for AQ production. AntJ heterogeneously activates the AQ production in single P. luminescens 1° cells, and blocks AQ production in 2° cells. AntJ contains a proposed ligand-binding WYL-domain, which is widespread among bacteria. AntJ is one of the rare examples of regulators that mediate heterogeneous gene expression by altering activity rather than copy number in single cells.
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Affiliation(s)
- Antje K Heinrich
- Fachbereich Biowissenschaften, Merck Stiftungsprofessur für Molekulare Biotechnologie, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - Angela Glaeser
- Bereich Mikrobiologie, Biozentrum Martinsried, Ludwig-Maximilians-Universität München, München, Germany
| | - Nicholas J Tobias
- Fachbereich Biowissenschaften, Merck Stiftungsprofessur für Molekulare Biotechnologie, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - Ralf Heermann
- Bereich Mikrobiologie, Biozentrum Martinsried, Ludwig-Maximilians-Universität München, München, Germany
| | - Helge B Bode
- Fachbereich Biowissenschaften, Merck Stiftungsprofessur für Molekulare Biotechnologie, Goethe-Universität Frankfurt, Frankfurt am Main, Germany; Buchmann Institute for Molecular Life Sciences (BMLS), Goethe-Universität Frankfurt, Frankfurt am Main, Germany
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14
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Death Becomes Them: Bacterial Community Dynamics and Stilbene Antibiotic Production in Cadavers of Galleria mellonella Killed by Heterorhabditis and Photorhabdus spp. Appl Environ Microbiol 2016; 82:5824-37. [PMID: 27451445 DOI: 10.1128/aem.01211-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/14/2016] [Indexed: 12/19/2022] Open
Abstract
UNLABELLED Insect larvae killed by entomopathogenic nematodes are thought to contain bacterial communities dominated by a single bacterial genus, that of the nematode's bacterial symbiont. In this study, we used next-generation sequencing to profile bacterial community dynamics in greater wax moth (Galleria mellonella) larvae cadavers killed by Heterorhabditis nematodes and their Photorhabdus symbionts. We found that, although Photorhabdus strains did initially displace an Enterococcus-dominated community present in uninfected G. mellonella insect larvae, the cadaver community was not static. Twelve days postinfection, Photorhabdus shared the cadaver with Stenotrophomonas species. Consistent with this result, Stenotrophomonas strains isolated from infected cadavers were resistant to Photorhabdus-mediated toxicity in solid coculture assays. We isolated and characterized a Photorhabdus-produced antibiotic from G. mellonella cadavers, produced it synthetically, and demonstrated that both the natural and synthetic compounds decreased G. mellonella-associated Enterococcus growth, but not Stenotrophomonas growth, in vitro Finally, we showed that the Stenotrophomonas strains described here negatively affected Photorhabdus growth in vitro Our results add an important dimension to a broader understanding of Heterorhabditis-Photorhabdus biology and also demonstrate that interspecific bacterial competition likely characterizes even a theoretically monoxenic environment, such as a Heterorhabditis-Photorhabdus-parasitized insect cadaver. IMPORTANCE Understanding, and eventually manipulating, both human and environmental health depends on a complete accounting of the forces that act on and shape microbial communities. One of these underlying forces is hypothesized to be resource competition. A resource that has received little attention in the general microbiological literature, but likely has ecological and evolutionary importance, is dead/decaying multicellular organisms. Metazoan cadavers, including those of insects, are ephemeral and nutrient-rich environments, where resource competition might shape interspecific macrobiotic and microbiotic interactions. This study is the first to use a next-generation sequencing approach to study the community dynamics of bacteria within a model insect cadaver system: insect larvae parasitized by entomopathogenic nematodes and their bacterial symbionts. By integrating bioinformatic, biochemical, and classic in vitro microbiological approaches, we have provided mechanistic insight into how antibiotic-mediated bacterial interactions may shape community dynamics within insect cadavers.
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15
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Tobias NJ, Heinrich AK, Eresmann H, Wright PR, Neubacher N, Backofen R, Bode HB. Photorhabdus‐nematode symbiosis is dependent onhfq‐mediated regulation of secondary metabolites. Environ Microbiol 2016; 19:119-129. [DOI: 10.1111/1462-2920.13502] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 08/16/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Nicholas J. Tobias
- Fachbereich BiowissenschaftenMerck Stiftungsprofessur für Molekulare Biotechnologie, Goethe Universität FrankfurtFrankfurt am Main Germany
| | - Antje K. Heinrich
- Fachbereich BiowissenschaftenMerck Stiftungsprofessur für Molekulare Biotechnologie, Goethe Universität FrankfurtFrankfurt am Main Germany
| | - Helena Eresmann
- Fachbereich BiowissenschaftenMerck Stiftungsprofessur für Molekulare Biotechnologie, Goethe Universität FrankfurtFrankfurt am Main Germany
| | - Patrick R. Wright
- Department of Computer ScienceBioinformatics Group, Albert Ludwigs University FreiburgFreiburg Germany
| | - Nick Neubacher
- Fachbereich BiowissenschaftenMerck Stiftungsprofessur für Molekulare Biotechnologie, Goethe Universität FrankfurtFrankfurt am Main Germany
| | - Rolf Backofen
- Department of Computer ScienceBioinformatics Group, Albert Ludwigs University FreiburgFreiburg Germany
- BIOSS Centre for Biological Signaling Studies, University of FreiburgFreiburg Germany
| | - Helge B. Bode
- Fachbereich BiowissenschaftenMerck Stiftungsprofessur für Molekulare Biotechnologie, Goethe Universität FrankfurtFrankfurt am Main Germany
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe Universität FrankfurtFrankfurt am Main Germany
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16
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Qiu X, Wu C, Cao L, Ehlers RU, Han R. Photorhabdus luminescens LN2 requires rpoS for nematicidal activity and nematode development. FEMS Microbiol Lett 2016; 363:fnw035. [PMID: 26884480 DOI: 10.1093/femsle/fnw035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2016] [Indexed: 11/15/2022] Open
Abstract
Photorhabdus (Enterobacteriaceae) bacteria are pathogenic to insects and mutualistic with entomopathogenic Heterorhabditis nematodes. Photorhabdus luminescens subsp. akhurstii LN2, associated with Heterorhabditis indica LN2, shows nematicidal activity against H. bacteriophora H06 infective juveniles (IJs). In the present study, an rpoS mutant of P. luminescens LN2 was generated through allelic exchange to examine the effects of rpoS deletion on the nematicidal activity and nematode development. The results showed that P. luminescens LN2 required rpoS for nematicidal activity against H06 nematodes, normal IJ recovery and development of H. indica LN2, however, not for the bacterial colonization in LN2 and H06 IJs. This provides cues for further understanding the role of rpoS in the mutualistic association between entomopathogenic nematodes and their symbionts.
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Affiliation(s)
- Xuehong Qiu
- Guangdong Entomological Institute, Public Laboratory of Wild Animal Conservation and Utilization, Key Laboratory of Integrated Pest Management in Agriculture, Guangzhou 510260, China
| | - Chunyan Wu
- Guangdong Entomological Institute, Public Laboratory of Wild Animal Conservation and Utilization, Key Laboratory of Integrated Pest Management in Agriculture, Guangzhou 510260, China
| | - Li Cao
- Guangdong Entomological Institute, Public Laboratory of Wild Animal Conservation and Utilization, Key Laboratory of Integrated Pest Management in Agriculture, Guangzhou 510260, China
| | - Ralf-Udo Ehlers
- E-nema GmbH, Klausdorfer Str. 28-36, Schwentinental 24223, Germany
| | - Richou Han
- Guangdong Entomological Institute, Public Laboratory of Wild Animal Conservation and Utilization, Key Laboratory of Integrated Pest Management in Agriculture, Guangzhou 510260, China
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17
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18
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Mulley G, Beeton ML, Wilkinson P, Vlisidou I, Ockendon-Powell N, Hapeshi A, Tobias NJ, Nollmann FI, Bode HB, van den Elsen J, ffrench-Constant RH, Waterfield NR. From Insect to Man: Photorhabdus Sheds Light on the Emergence of Human Pathogenicity. PLoS One 2015; 10:e0144937. [PMID: 26681201 PMCID: PMC4683029 DOI: 10.1371/journal.pone.0144937] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 11/25/2015] [Indexed: 12/27/2022] Open
Abstract
Photorhabdus are highly effective insect pathogenic bacteria that exist in a mutualistic relationship with Heterorhabditid nematodes. Unlike other members of the genus, Photorhabdus asymbiotica can also infect humans. Most Photorhabdus cannot replicate above 34°C, limiting their host-range to poikilothermic invertebrates. In contrast, P. asymbiotica must necessarily be able to replicate at 37°C or above. Many well-studied mammalian pathogens use the elevated temperature of their host as a signal to regulate the necessary changes in gene expression required for infection. Here we use RNA-seq, proteomics and phenotype microarrays to examine temperature dependent differences in transcription, translation and phenotype of P. asymbiotica at 28°C versus 37°C, relevant to the insect or human hosts respectively. Our findings reveal relatively few temperature dependant differences in gene expression. There is however a striking difference in metabolism at 37°C, with a significant reduction in the range of carbon and nitrogen sources that otherwise support respiration at 28°C. We propose that the key adaptation that enables P. asymbiotica to infect humans is to aggressively acquire amino acids, peptides and other nutrients from the human host, employing a so called “nutritional virulence” strategy. This would simultaneously cripple the host immune response while providing nutrients sufficient for reproduction. This might explain the severity of ulcerated lesions observed in clinical cases of Photorhabdosis. Furthermore, while P. asymbiotica can invade mammalian cells they must also resist immediate killing by humoral immunity components in serum. We observed an increase in the production of the insect Phenol-oxidase inhibitor Rhabduscin normally deployed to inhibit the melanisation immune cascade. Crucially we demonstrated this molecule also facilitates protection against killing by the alternative human complement pathway.
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Affiliation(s)
- Geraldine Mulley
- School of Biological Sciences, University of Reading, Whiteknights, Reading, RG6 6AJ, United Kingdom
| | - Michael L Beeton
- Cardiff School of Health Sciences, Cardiff Metropolitan University, Llandaff Campus, Western Avenue, Cardiff, CF5 2YB, United Kingdom
| | - Paul Wilkinson
- Life Sciences Building, Bristol University, 24 Tyndall Avenue, Bristol, BS8 1TQ, United Kingdom
| | - Isabella Vlisidou
- Life Sciences Building, Bristol University, 24 Tyndall Avenue, Bristol, BS8 1TQ, United Kingdom
| | - Nina Ockendon-Powell
- Primary Care Unit, Microbiology Department, Public Health England, Gloucester Royal Hospital, Great Western Road, Gloucester, GL1 3NN, United Kingdom
| | - Alexia Hapeshi
- Division of Biomedical Sciences, Warwick Medical School, Medical School Building, The University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - Nick J Tobias
- Buchmann Center for Life Sciences (BMLS), Fachbereich Biowissenschaften, Goethe Universität Frankfurt, 60438, Frankfurt, Germany
| | - Friederike I Nollmann
- Buchmann Center for Life Sciences (BMLS), Fachbereich Biowissenschaften, Goethe Universität Frankfurt, 60438, Frankfurt, Germany
| | - Helge B Bode
- Buchmann Center for Life Sciences (BMLS), Fachbereich Biowissenschaften, Goethe Universität Frankfurt, 60438, Frankfurt, Germany
| | - Jean van den Elsen
- Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom
| | | | - Nicholas R Waterfield
- Division of Biomedical Sciences, Warwick Medical School, Medical School Building, The University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
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19
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Elucidation of the Photorhabdus temperata Genome and Generation of a Transposon Mutant Library To Identify Motility Mutants Altered in Pathogenesis. J Bacteriol 2015; 197:2201-2216. [PMID: 25917908 DOI: 10.1128/jb.00197-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 04/17/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The entomopathogenic nematode Heterorhabditis bacteriophora forms a specific mutualistic association with its bacterial partner Photorhabdus temperata. The microbial symbiont is required for nematode growth and development, and symbiont recognition is strain specific. The aim of this study was to sequence the genome of P. temperata and identify genes that plays a role in the pathogenesis of the Photorhabdus-Heterorhabditis symbiosis. A draft genome sequence of P. temperata strain NC19 was generated. The 5.2-Mb genome was organized into 17 scaffolds and contained 4,808 coding sequences (CDS). A genetic approach was also pursued to identify mutants with altered motility. A bank of 10,000 P. temperata transposon mutants was generated and screened for altered motility patterns. Five classes of motility mutants were identified: (i) nonmotile mutants, (ii) mutants with defective or aberrant swimming motility, (iii) mutant swimmers that do not require NaCl or KCl, (iv) hyperswimmer mutants that swim at an accelerated rate, and (v) hyperswarmer mutants that are able to swarm on the surface of 1.25% agar. The transposon insertion sites for these mutants were identified and used to investigate other physiological properties, including insect pathogenesis. The motility-defective mutant P13-7 had an insertion in the RNase II gene and showed reduced virulence and production of extracellular factors. Genetic complementation of this mutant restored wild-type activity. These results demonstrate a role for RNA turnover in insect pathogenesis and other physiological functions. IMPORTANCE The relationship between Photorhabdus and entomopathogenic nematode Heterorhabditis represents a well-known mutualistic system that has potential as a biological control agent. The elucidation of the genome of the bacterial partner and role that RNase II plays in its life cycle has provided a greater understanding of Photorhabdus as both an insect pathogen and a nematode symbiont.
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20
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The genetic basis of the symbiosis between Photorhabdus and its invertebrate hosts. ADVANCES IN APPLIED MICROBIOLOGY 2014; 88:1-29. [PMID: 24767424 DOI: 10.1016/b978-0-12-800260-5.00001-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Photorhabdus is a pathogen of insects that also maintains a mutualistic association with nematodes from the family Heterorhabditis. Photorhabdus colonizes the gut of the infective juvenile (IJ) stage of the nematode. The IJ infects an insect and regurgitates the bacteria and the bacteria reproduce to kill the insect. The nematodes feed on the resulting bacterial biomass until a new generation of IJs emerges from the insect cadaver. Therefore, during its life cycle, Photorhabdus must (1) kill the insect host, (2) support nematode growth and development, and (3) be able to colonize the new generation of IJs. In this review, functional genomic studies that have been aimed at understanding the molecular mechanisms underpinning each of these roles will be discussed. These studies have begun to reveal that distinct gene sets may be required for each of these interactions, suggesting that there is only a minimal genetic overlap between pathogenicity and mutualism in Photorhabdus.
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21
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Lango-Scholey L, Brachmann AO, Bode HB, Clarke DJ. The expression of stlA in Photorhabdus luminescens is controlled by nutrient limitation. PLoS One 2013; 8:e82152. [PMID: 24278476 PMCID: PMC3838401 DOI: 10.1371/journal.pone.0082152] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 10/24/2013] [Indexed: 11/22/2022] Open
Abstract
Photorhabdus is a genus of Gram-negative entomopathogenic bacteria that also maintain a mutualistic association with nematodes from the family Heterorhabditis. Photorhabdus has an extensive secondary metabolism that is required for the interaction between the bacteria and the nematode. A major component of this secondary metabolism is a stilbene molecule, called ST. The first step in ST biosynthesis is the non-oxidative deamination of phenylalanine resulting in the production of cinnamic acid. This reaction is catalyzed by phenylalanine-ammonium lyase, an enzyme encoded by the stlA gene. In this study we show, using a stlA-gfp transcriptional fusion, that the expression of stlA is regulated by nutrient limitation through a regulatory network that involves at least 3 regulators. We show that TyrR, a LysR-type transcriptional regulator that regulates gene expression in response to aromatic amino acids in E. coli, is absolutely required for stlA expression. We also show that stlA expression is modulated by σS and Lrp, regulators that are implicated in the regulation of the response to nutrient limitation in other bacteria. This work is the first that describes pathway-specific regulation of secondary metabolism in Photorhabdus and, therefore, our study provides an initial insight into the complex regulatory network that controls secondary metabolism, and therefore mutualism, in this model organism.
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Affiliation(s)
| | - Alexander O. Brachmann
- Molecular Biotechnology, Institute for Molecular Biosciences, Goethe University, Frankfurt, Frankfurt, Germany
| | - Helge B. Bode
- Molecular Biotechnology, Institute for Molecular Biosciences, Goethe University, Frankfurt, Frankfurt, Germany
| | - David J. Clarke
- Department of Microbiology, University College Cork, Cork, Ireland
- * E-mail:
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22
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Stein ML, Groll M. Applied techniques for mining natural proteasome inhibitors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:26-38. [PMID: 23360979 DOI: 10.1016/j.bbamcr.2013.01.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 01/14/2013] [Indexed: 11/17/2022]
Abstract
In eukaryotic cells, the ubiquitin-proteasome-system (UPS) is responsible for the non-lysosomal degradation of proteins and plays a pivotal role in such vital processes as protein homeostasis, antigen processing or cell proliferation. Therefore, it is an attractive drug target with various applications in cancer and immunosuppressive therapies. Being an evolutionary well conserved pathway, many pathogenic bacteria have developed small molecules, which modulate the activity of their hosts' UPS components. Such natural products are, due to their stepwise optimization over the millennia, highly potent in terms of their binding mechanisms, their bioavailability and selectivity. Generally, this makes bioactive natural products an ideal starting point for the development of novel drugs. Since four out of the ten best seller drugs are natural product derivatives, research in this field is still of unfathomable value for the pharmaceutical industry. The currently most prominent example for the successful exploitation of a natural compound in the UPS field is carfilzomib (Kyprolis®), which represents the second FDA approved drug targeting the proteasome after the admission of the blockbuster bortezomib (Velcade®) in 2003. On the other hand side of the spectrum, ONX 0914, which is derived from the same natural product as carfilzomib, has been shown to selectively inhibit the immune response related branch of the pathway. To date, there exists a huge potential of UPS inhibitors with regard to many diseases. Both approved drugs against the proteasome show severe side effects, adaptive resistances and limited applicability, thus the development of novel compounds with enhanced properties is a main objective of active research. In this review, we describe the techniques, which can be utilized for the discovery of novel natural inhibitors, which in particular block the 20S proteasomal activity. In addition, we will illustrate the successful implementation of a recently published methodology with the example of a highly potent but so far unexploited group of proteasome inhibitors, the syrbactins, and their biological functions. This article is part of a Special Issue entitled: Ubiquitin-Proteasome System. Guest Editors: Thomas Sommer and Dieter H. Wolf.
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Affiliation(s)
- Martin L Stein
- Center for Integrated Protein Science at the Department Chemie, Lehrstuhl für Biochemie, Technische Unversität München, Lichtenbergstraße 4, 85748 Garching, Germany.
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23
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Zhou Q, Dowling A, Heide H, Wöhnert J, Brandt U, Baum J, Ffrench-Constant R, Bode HB. Xentrivalpeptides A-Q: depsipeptide diversification in Xenorhabdus. JOURNAL OF NATURAL PRODUCTS 2012; 75:1717-1722. [PMID: 23025386 DOI: 10.1021/np300279g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Seventeen depsipeptides, xentrivalpeptides A-Q (1-17), have been identified from an entomopathogenic Xenorhabdus sp. Whereas the structure of xentrivalpeptide A (1) was determined after its isolation by NMR spectroscopy and the advanced Marfey's method, the structures of all other derivatives were determined using a combination of stable isotope labeling and detailed MS analysis.
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Affiliation(s)
- Qiuqin Zhou
- Institut für Molekulare Biowissenschaften, Goethe Universität Frankfurt, 60438 Frankfurt am Main, Germany
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