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Guden RM, Derycke S, Moens T. To stay or to go: resource diversity alters the dispersal behavior of sympatric cryptic marine nematodes. PeerJ 2025; 13:e18790. [PMID: 39822968 PMCID: PMC11737338 DOI: 10.7717/peerj.18790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 12/10/2024] [Indexed: 01/19/2025] Open
Abstract
Animals can use specific environmental cues to make informed decisions about whether and where to disperse. Patch conditions are known to affect the dispersal behavior of animals, but empirical studies investigating the impact of resource diversity on the dispersal of closely related species are largely lacking. In this study, we investigated how food diversity affects the dispersal behavior of three co-occurring cryptic species of the marine bacterivorous nematode complex Litoditis marina (Pm I, Pm III and Pm IV). Using microcosms composed of a local patch (inoculation plate), a connection tube, and a distant patch (dispersal plate), we examined nematode dispersal patterns with bacteria serving as the food source. Food treatments included low-, medium-, and high-diversity bacterial mixtures of 5, 10, and 15 bacterial strains, respectively. Additionally, a single-strain food resource Escherichia coli was used as a control treatment. Both local and distant patches had either identical food treatments ('homogeneous patches') or E. coli in the local patches and more diverse food (low-, medium-, or high-diversity food) in distant patches ('heterogeneous patches'). Our results show that the dispersal behavior of the cryptic species varies depending on food diversity, indicating that L. marina acquire information about their environment when making dispersal decisions. All three cryptic species tend to disperse faster toward food patches that increase fitness. Pm I and Pm IV exhibited faster dispersal toward patches with a more diverse food source, while Pm III showed similar dispersal rates toward E. coli, medium-diversity, and high-diversity food. This indicates that resource diversity can alter the dispersal behavior of cryptic species and may be an important mechanism to achieve species coexistence in the field.
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Affiliation(s)
- Rodgee Mae Guden
- Marine Biology Unit, Department of Biology, Ghent University, Ghent, Belgium
| | - Sofie Derycke
- Marine Biology Unit, Department of Biology, Ghent University, Ghent, Belgium
- Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Aquatic Environment and Quality, Oostende, Belgium
| | - Tom Moens
- Marine Biology Unit, Department of Biology, Ghent University, Ghent, Belgium
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2
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Weigert Muñoz A, Zhao W, Sieber SA. Monitoring host-pathogen interactions using chemical proteomics. RSC Chem Biol 2024; 5:73-89. [PMID: 38333198 PMCID: PMC10849124 DOI: 10.1039/d3cb00135k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 11/09/2023] [Indexed: 02/10/2024] Open
Abstract
With the rapid emergence and the dissemination of microbial resistance to conventional chemotherapy, the shortage of novel antimicrobial drugs has raised a global health threat. As molecular interactions between microbial pathogens and their mammalian hosts are crucial to establish virulence, pathogenicity, and infectivity, a detailed understanding of these interactions has the potential to reveal novel therapeutic targets and treatment strategies. Bidirectional molecular communication between microbes and eukaryotes is essential for both pathogenic and commensal organisms to colonise their host. In particular, several devastating pathogens exploit host signalling to adjust the expression of energetically costly virulent behaviours. Chemical proteomics has emerged as a powerful tool to interrogate the protein interaction partners of small molecules and has been successfully applied to advance host-pathogen communication studies. Here, we present recent significant progress made by this approach and provide a perspective for future studies.
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Affiliation(s)
- Angela Weigert Muñoz
- Center for Functional Protein Assemblies, Department of Bioscience, TUM School of Natural Sciences, Technical University of Munich Ernst-Otto-Fischer-Straße 8 D-85748 Garching Germany
| | - Weining Zhao
- College of Pharmacy, Shenzhen Technology University Shenzhen 518118 China
| | - Stephan A Sieber
- Center for Functional Protein Assemblies, Department of Bioscience, TUM School of Natural Sciences, Technical University of Munich Ernst-Otto-Fischer-Straße 8 D-85748 Garching Germany
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) Germany
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3
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Madhu B, Lakdawala MF, Gumienny TL. The DBL-1/TGF-β signaling pathway tailors behavioral and molecular host responses to a variety of bacteria in Caenorhabditis elegans. eLife 2023; 12:e75831. [PMID: 37750680 PMCID: PMC10567113 DOI: 10.7554/elife.75831] [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: 12/07/2021] [Accepted: 09/25/2023] [Indexed: 09/27/2023] Open
Abstract
Generating specific, robust protective responses to different bacteria is vital for animal survival. Here, we address the role of transforming growth factor β (TGF-β) member DBL-1 in regulating signature host defense responses in Caenorhabditis elegans to human opportunistic Gram-negative and Gram-positive pathogens. Canonical DBL-1 signaling is required to suppress avoidance behavior in response to Gram-negative, but not Gram-positive bacteria. We propose that in the absence of DBL-1, animals perceive some bacteria as more harmful. Animals activate DBL-1 pathway activity in response to Gram-negative bacteria and strongly repress it in response to select Gram-positive bacteria, demonstrating bacteria-responsive regulation of DBL-1 signaling. DBL-1 signaling differentially regulates expression of target innate immunity genes depending on the bacterial exposure. These findings highlight a central role for TGF-β in tailoring a suite of bacteria-specific host defenses.
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Affiliation(s)
- Bhoomi Madhu
- Department of Biology, Texas Woman’s UniversityDentonUnited States
- Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Mohammed Farhan Lakdawala
- Department of Biology, Texas Woman’s UniversityDentonUnited States
- AbbVie (United States)WorcesterUnited States
| | - Tina L Gumienny
- Department of Biology, Texas Woman’s UniversityDentonUnited States
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4
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Li B, Wang P, Yang L, Rang X, Zhou W, Liu Y. Chemotaxis of Meloidogyne incognita Response to Rhizosphere Bacteria. Microorganisms 2023; 11:2271. [PMID: 37764115 PMCID: PMC10536184 DOI: 10.3390/microorganisms11092271] [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: 08/10/2023] [Revised: 08/28/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
Rhizosphere microorganisms and the volatile organic compounds (VOCs) produced by them take part in the regulation of the chemotaxis of nematodes. A total of 150 strains of rhizosphere bacteria were screened via a chemotaxis experiment with Meloidogyne incognita. Some isolates affected the behavior of the nematodes, including attraction, randomness, and repulsion. Volatile metabolites produced via the selected bacteria were associated with the chemotaxis of nematodes. M. incognita was highly attracted to decanal. In addition, dimethyl disulfide, 2,5-dimethylpyrazine, pentadecanoic acid, and palmitic acid were found to attract weakly M. incognita. Furthermore, the chemotaxis of M. incognita was tested in a pot experiment. The bacteria Bacillus sp. 1-50, Brevibacillus brevis 2-35, B. cereus 5-14, Chryseobacterium indologens 6-4, and VOC decanal could regulate the movement of M. incognita in the pot with or without plants. The results provide insights into rhizosphere microorganisms and their VOCs and how they regulate the chemotaxis of the nematodes.
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Affiliation(s)
| | | | | | | | | | - Yajun Liu
- State Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming 650091, China; (B.L.); (P.W.); (L.Y.); (X.R.); (W.Z.)
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5
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De-Souza EA, Thompson MA, Taylor RC. Olfactory chemosensation extends lifespan through TGF-β signaling and UPR activation. NATURE AGING 2023; 3:938-947. [PMID: 37500972 PMCID: PMC10432268 DOI: 10.1038/s43587-023-00467-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 07/04/2023] [Indexed: 07/29/2023]
Abstract
Animals rely on chemosensory cues to survive in pathogen-rich environments. In Caenorhabditis elegans, pathogenic bacteria trigger aversive behaviors through neuronal perception and activate molecular defenses throughout the animal. This suggests that neurons can coordinate the activation of organism-wide defensive responses upon pathogen perception. In this study, we found that exposure to volatile pathogen-associated compounds induces activation of the endoplasmic reticulum unfolded protein response (UPRER) in peripheral tissues after xbp-1 splicing in neurons. This odorant-induced UPRER activation is dependent upon DAF-7/transforming growth factor beta (TGF-β) signaling and leads to extended lifespan and enhanced clearance of toxic proteins. Notably, rescue of the DAF-1 TGF-β receptor in RIM/RIC interneurons is sufficient to significantly recover UPRER activation upon 1-undecene exposure. Our data suggest that the cell non-autonomous UPRER rewires organismal proteostasis in response to pathogen detection, pre-empting proteotoxic stress. Thus, chemosensation of particular odors may be a route to manipulation of stress responses and longevity.
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Affiliation(s)
- Evandro A De-Souza
- Neurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.
| | - Maximillian A Thompson
- Neurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.
| | - Rebecca C Taylor
- Neurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.
- School of Biological Sciences, University of East Anglia, Norwich, UK.
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6
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Laganenka L, Sourjik V. Bacterial Quorum Sensing Signals at the Interdomain Interface. Isr J Chem 2022. [DOI: 10.1002/ijch.202200080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
| | - Victor Sourjik
- Max Planck Institute for Terrestrial Microbiology and Center for Synthetic Microbiology (SYNMIKRO) Marburg Germany
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7
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Li S, Liu SY, Chan SY, Chua SL. Biofilm matrix cloaks bacterial quorum sensing chemoattractants from predator detection. THE ISME JOURNAL 2022; 16:1388-1396. [PMID: 35034106 PMCID: PMC9038794 DOI: 10.1038/s41396-022-01190-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 12/29/2021] [Accepted: 01/06/2022] [Indexed: 11/09/2022]
Abstract
Microbes often secrete high levels of quorum sensing (QS) autoinducers into the environment to coordinate gene expression and biofilm formation, but risk detection and subsequent predation by bacterivorous predators. With such prominent signaling molecules acting as chemoattractants that diffuse into the environment at alarmingly high concentrations, it is unclear if bacterial cells can mask their chemical trails from predator detection. Here, we describe a microbial-based anti-detection adaptation, termed as "biofilm cloak", where the biofilm prey produced biofilm matrix exopolysaccharides that "locked" and reduced the leaching of autoinducers into the milieu, thereby concealing their trails to the detection by the bacterivorous Caenorhabditis elegans nematode. The exopolysaccharides act as common good for the non-producers to hide their autoinducers from predator detection. Deficiency in chemosensory gene odr-10 in mutant animals abrogated their ability to detect autoinducers and migrate toward their prey in a directed manner, which led to lower population growth rate of animals. Hence, restriction of bacterial communication activities to the confinements of biofilms is a novel approach for predator evasion, which plays a fundamental role in shaping ecological dynamics of microbial communities and predator-prey interactions.
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Affiliation(s)
- Shaoyang Li
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Sylvia Yang Liu
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Shepherd Yuen Chan
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Song Lin Chua
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China.
- State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China.
- Shenzhen Key Laboratory of Food Biological Safety Control, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China.
- Research Centre for Deep Space Explorations (RCDSE), The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China.
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8
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Lanza E, Di Rocco M, Schwartz S, Caprini D, Milanetti E, Ferrarese G, Lonardo MT, Pannone L, Ruocco G, Martinelli S, Folli V. C. elegans-based chemosensation strategy for the early detection of cancer metabolites in urine samples. Sci Rep 2021; 11:17133. [PMID: 34429473 PMCID: PMC8385061 DOI: 10.1038/s41598-021-96613-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/10/2021] [Indexed: 02/07/2023] Open
Abstract
Chemosensory receptors play a crucial role in distinguishing the wide range of volatile/soluble molecules by binding them with high accuracy. Chemosensation is the main sensory modality in organisms lacking long-range sensory mechanisms like vision/hearing. Despite its low number of sensory neurons, the nematode Caenorhabditis elegans possesses several chemosensory receptors, allowing it to detect about as many odorants as mammals. Here, we show that C. elegans displays attraction towards urine samples of women with breast cancer, avoiding control ones. Behavioral assays on animals lacking AWC sensory neurons demonstrate the relevance of these neurons in sensing cancer odorants: calcium imaging on AWC increases the accuracy of the discrimination (97.22%). Also, chemotaxis assays on animals lacking GPCRs expressed in AWC allow to identify receptors involved in binding cancer metabolites, suggesting that an alteration of a few metabolites is sufficient for the cancer discriminating behavior of C. elegans, which may help identify a fundamental fingerprint of breast cancer.
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Affiliation(s)
- Enrico Lanza
- grid.25786.3e0000 0004 1764 2907Istituto Italiano di Tecnologia, Center for Life Nano Science, Rome, 00161 Italy
| | - Martina Di Rocco
- grid.25786.3e0000 0004 1764 2907Istituto Italiano di Tecnologia, Center for Life Nano Science, Rome, 00161 Italy ,grid.416651.10000 0000 9120 6856Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, 00161 Italy ,grid.7841.aDepartment of Biochemical Science “A. Rossi Fanelli”, Sapienza Università di Roma, 00185 Rome, Italy
| | - Silvia Schwartz
- grid.25786.3e0000 0004 1764 2907Istituto Italiano di Tecnologia, Center for Life Nano Science, Rome, 00161 Italy
| | - Davide Caprini
- grid.25786.3e0000 0004 1764 2907Istituto Italiano di Tecnologia, Center for Life Nano Science, Rome, 00161 Italy
| | - Edoardo Milanetti
- grid.25786.3e0000 0004 1764 2907Istituto Italiano di Tecnologia, Center for Life Nano Science, Rome, 00161 Italy ,grid.7841.aDepartment of Physics, Sapienza Università di Roma, Rome, 00185 Italy
| | - Giuseppe Ferrarese
- grid.25786.3e0000 0004 1764 2907Istituto Italiano di Tecnologia, Center for Life Nano Science, Rome, 00161 Italy
| | | | - Luca Pannone
- grid.414125.70000 0001 0727 6809Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, RM 00165 Italy
| | - Giancarlo Ruocco
- grid.25786.3e0000 0004 1764 2907Istituto Italiano di Tecnologia, Center for Life Nano Science, Rome, 00161 Italy
| | - Simone Martinelli
- grid.416651.10000 0000 9120 6856Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, 00161 Italy
| | - Viola Folli
- grid.25786.3e0000 0004 1764 2907Istituto Italiano di Tecnologia, Center for Life Nano Science, Rome, 00161 Italy
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9
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Manterola M, Palominos MF, Calixto A. The Heritability of Behaviors Associated With the Host Gut Microbiota. Front Immunol 2021; 12:658551. [PMID: 34054822 PMCID: PMC8155505 DOI: 10.3389/fimmu.2021.658551] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/12/2021] [Indexed: 12/13/2022] Open
Abstract
What defines whether the interaction between environment and organism creates a genetic memory able to be transferred to subsequent generations? Bacteria and the products of their metabolism are the most ubiquitous biotic environments to which every living organism is exposed. Both microbiota and host establish a framework where environmental and genetic factors are integrated to produce adaptive life traits, some of which can be inherited. Thus, the interplay between host and microbe is a powerful model to study how phenotypic plasticity is inherited. Communication between host and microbe can occur through diverse molecules such as small RNAs (sRNAs) and the RNA interference machinery, which have emerged as mediators and carriers of heritable environmentally induced responses. Notwithstanding, it is still unclear how the organism integrates sRNA signaling between different tissues to orchestrate a systemic bacterially induced response that can be inherited. Here we discuss current evidence of heritability produced by the intestinal microbiota from several species. Neurons and gut are the sensing systems involved in transmitting changes through transcriptional and post-transcriptional modifications to the gonads. Germ cells express inflammatory receptors, and their development and function are regulated by host and bacterial metabolites and sRNAs thus suggesting that the dynamic interplay between host and microbe underlies the host's capacity to transmit heritable behaviors. We discuss how the host detects changes in the microbiota that can modulate germ cells genomic functions. We also explore the nature of the interactions that leave permanent or long-term memory in the host and propose mechanisms by which the microbiota can regulate the development and epigenetic reprogramming of germ cells, thus influencing the inheritance of the host. We highlight the vast contribution of the bacterivore nematode C. elegans and its commensal and pathogenic bacteria to the understanding on how behavioral adaptations can be inter and transgenerational inherited.
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Affiliation(s)
- Marcia Manterola
- Programa de Genética Humana, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - M. Fernanda Palominos
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaiso, Chile
- Programa de Doctorado en Ciencias, mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaiso, Chile
| | - Andrea Calixto
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaiso, Chile
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10
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Costa SR, Ng JLP, Mathesius U. Interaction of Symbiotic Rhizobia and Parasitic Root-Knot Nematodes in Legume Roots: From Molecular Regulation to Field Application. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:470-490. [PMID: 33471549 DOI: 10.1094/mpmi-12-20-0350-fi] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Legumes form two types of root organs in response to signals from microbes, namely, nodules and root galls. In the field, these interactions occur concurrently and often interact with each other. The outcomes of these interactions vary and can depend on natural variation in rhizobia and nematode populations in the soil as well as abiotic conditions. While rhizobia are symbionts that contribute fixed nitrogen to their hosts, parasitic root-knot nematodes (RKN) cause galls as feeding structures that consume plant resources without a contribution to the plant. Yet, the two interactions share similarities, including rhizosphere signaling, repression of host defense responses, activation of host cell division, and differentiation, nutrient exchange, and alteration of root architecture. Rhizobia activate changes in defense and development through Nod factor signaling, with additional functions of effector proteins and exopolysaccharides. RKN inject large numbers of protein effectors into plant cells that directly suppress immune signaling and manipulate developmental pathways. This review examines the molecular control of legume interactions with rhizobia and RKN to elucidate shared and distinct mechanisms of these root-microbe interactions. Many of the molecular pathways targeted by both organisms overlap, yet recent discoveries have singled out differences in the spatial control of expression of developmental regulators that may have enabled activation of cortical cell division during nodulation in legumes. The interaction of legumes with symbionts and parasites highlights the importance of a comprehensive view of root-microbe interactions for future crop management and breeding strategies.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Sofia R Costa
- CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Jason Liang Pin Ng
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra ACT 2601, Australia
| | - Ulrike Mathesius
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra ACT 2601, Australia
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11
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Angeloni J, Dong Y, Wang Z, Cao M. Bacterial second messenger 3',5'-cyclic diguanylate attracts Caenorhabditis elegans and suppresses its immunity. Commun Biol 2020; 3:700. [PMID: 33219258 PMCID: PMC7679379 DOI: 10.1038/s42003-020-01436-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 10/26/2020] [Indexed: 11/29/2022] Open
Abstract
Cyclic di-nucleotides are important secondary signaling molecules in bacteria that regulate a wide range of processes. In this study, we found that Caenorhabditis elegans can detect and are attracted to multiple signal molecules produced by Vibrio cholerae, specifically the 3′,5′-cyclic diguanylate (c-di-GMP), even though this bacterium kills the host at a high rate. C-di-GMP is sensed through C. elegans olfactory AWC neurons, which then evokes a series of signal transduction pathways that lead to reduced activity of two key stress response transcription factors, SKN-1 and HSF-1, and weakened innate immunity. Taken together, our study elucidates the role of c-di-GMP in interkingdom communication. For C. elegans, bacterial c-di-GMP may serve as a cue that they can use to detect food. On the other hand, preexposure to low concentrations of c-di-GMP may impair their immune response, which could facilitate bacterial invasion and survival. Joseph Angeloni et al. show that Caenorhabditis elegans can detect and are attracted to multiple signal molecules produced by the bacterium Vibrio cholerae, specifically the 3′,5′-cyclic diguanylate (c-di-GMP), even though this bacterium kills the host at a high rate. This study reveals how bacterial c-di-GMP may serve as a cue for C. elegans that they can use to detect food or alternatively, impair their immune response, which could facilitate bacterial invasion and survival.
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Affiliation(s)
- Joseph Angeloni
- Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC, 29634, USA
| | - Yuqing Dong
- Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC, 29634, USA.,Institute for Engaged Aging, Clemson University, 2037 Barre Hall, Clemson, SC, 29634, USA
| | - Zeneng Wang
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA
| | - Min Cao
- Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC, 29634, USA. .,Institute for Engaged Aging, Clemson University, 2037 Barre Hall, Clemson, SC, 29634, USA.
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12
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Gamalero E, Glick BR. The Use of Plant Growth-Promoting Bacteria to Prevent Nematode Damage to Plants. BIOLOGY 2020; 9:biology9110381. [PMID: 33171782 PMCID: PMC7695023 DOI: 10.3390/biology9110381] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 10/31/2020] [Accepted: 11/04/2020] [Indexed: 01/17/2023]
Abstract
Simple Summary It has been estimated that 100 g of bulk soil can host about 2000–4000 nematodes and this amount is increased 5-fold in the rhizosphere. A certain number of these nematodes are pathogenic for plants and cause yield and economic losses. Application of chemical nematicides is the most common method used to reduce nematode populations, but these chemicals can have a negative impact on both the environment and human health. Therefore, other more environmentally friendly methods of suppression of plant-parasitic nematodes have been proposed. Among them, the use of plant beneficial soil bacteria, behaving as biocontrol agents against nematodes, represent a potential alternative to chemicals. Abstract Plant-parasitic nematodes have been estimated to annually cause around US $173 billion in damage to plant crops worldwide. Moreover, with global climate change, it has been suggested that the damage to crops from nematodes is likely to increase in the future. Currently, a variety of potentially dangerous and toxic chemical agents are used to limit the damage to crops by plant-parasitic nematodes. As an alternative to chemicals and a more environmentally friendly means of decreasing nematode damage to plants, researchers have begun to examine the possible use of various soil bacteria, including plant growth-promoting bacteria (PGPB). Here, the current literature on some of the major mechanisms employed by these soil bacteria is examined. It is expected that within the next 5–10 years, as scientists continue to elaborate the mechanisms used by these bacteria, biocontrol soil bacteria will gradually replace the use of chemicals as nematicides.
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Affiliation(s)
- Elisa Gamalero
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, Viale T. Michel 11, 15121 Alessandria, Italy
- Correspondence: ; Tel.: +39-0131-360238
| | - Bernard R. Glick
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada;
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13
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Abstract
Microbes are ubiquitous in the natural environment of Caenorhabditis elegans. Bacteria serve as a food source for C. elegans but may also cause infection in the nematode host. The sensory nervous system of C. elegans detects diverse microbial molecules, ranging from metabolites produced by broad classes of bacteria to molecules synthesized by specific strains of bacteria. Innate recognition through chemosensation of bacterial metabolites or mechanosensation of bacteria can induce immediate behavioral responses. The ingestion of nutritive or pathogenic bacteria can modulate internal states that underlie long-lasting behavioral changes. Ingestion of nutritive bacteria leads to learned attraction and exploitation of the bacterial food source. Infection, which is accompanied by activation of innate immunity, stress responses, and host damage, leads to the development of aversive behavior. The integration of a multitude of microbial sensory cues in the environment is shaped by experience and context. Genetic, chemical, and neuronal studies of C. elegans behavior in the presence of bacteria have defined neural circuits and neuromodulatory systems that shape innate and learned behavioral responses to microbial cues. These studies have revealed the profound influence that host-microbe interactions have in governing the behavior of this simple animal host.
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Affiliation(s)
- Dennis H Kim
- Division of Infectious Diseases, Boston Children's Hospital, and Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Steven W Flavell
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
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14
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Velagapudi P, Ghoubrial R, Shah R, Ghali H, Haas M, Patel KS, Riddell A, Blanar CA, Smith RP. A potential tradeoff between feeding rate and aversive learning determines intoxication in a Caenorhabditis elegans host-pathogen system. Microbes Infect 2020; 22:340-348. [PMID: 32014589 DOI: 10.1016/j.micinf.2020.01.002] [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: 06/03/2019] [Revised: 01/15/2020] [Accepted: 01/16/2020] [Indexed: 11/29/2022]
Abstract
Despite being the first line of defense against infection, little is known about how host-pathogen interactions determine avoidance. Caenorhabditis elegans can become infected by chemoattractant-producing bacteria through ingestion. The worms can learn to associate these chemoattractants with harm through aversive learning. As a result, the worms will avoid the pathogen. Evolutionary constraints have likely shaped the attraction, intoxication and learning dynamics between bacteria and C. elegans, but these have not been explored. Using bacteria engineered to express an acylhomoserine lactone chemoattractant and a nematicidal protein, we explored how manipulating the amount of attractant produced by the bacteria affects learning and intoxication in mixed stage populations of C. elegans. We found that increasing the production rate of the chemoattractant increased the feeding rate in C. elegans, but decreased the time required for C. elegans to learn to avoid the chemoattractant. Learning generally coincided with a decreased feeding rate. We also observed that the percentage of intoxicated worms was maximized at intermediate production rates of the attractant. We propose that interactions between attractant driven feeding rate and aversive learning are likely responsible for this trend. Our results increase our understanding of behavioral avoidance in C. elegans and have implications in understanding host-pathogen dynamics that shape avoidance.
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Affiliation(s)
- Pallavi Velagapudi
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Rachel Ghoubrial
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Ratnavi Shah
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Helana Ghali
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Meghan Haas
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Krunal S Patel
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Ashleigh Riddell
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Christopher A Blanar
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Robert P Smith
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA.
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15
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Sharrock J, Sun JC. Innate immunological memory: from plants to animals. Curr Opin Immunol 2020; 62:69-78. [PMID: 31931432 DOI: 10.1016/j.coi.2019.12.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 12/02/2019] [Accepted: 12/06/2019] [Indexed: 02/07/2023]
Abstract
Immunological memory is defined by the ability of the host to recognise and mount a robust secondary response against a previously encountered pathogen. Classic immune memory is an evolutionary adaptation of the vertebrate immune system that has been attributed to adaptive lymphocytes, including T and B cells. In contrast, the innate immune system was known for its conserved, non-specific roles in rapid host defence, but historically was considered to be unable to generate memory. Recent studies have challenged our understanding of innate immunity and now provides a growing body of evidence for innate immune memory. However, in many species and in various cell types the underlying mechanisms of immune 'memory' formation remain poorly understood. The purpose of this review is to explore and summarise the emerging evidence for immunological 'memory' in plants, invertebrates, and vertebrates.
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Affiliation(s)
- Jessica Sharrock
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, United States
| | - Joseph C Sun
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, United States; Department of Immunology and Microbial Pathogenesis, Weill Cornell Medical College, New York, NY 10065, United States.
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16
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Singh J, Aballay A. Intestinal infection regulates behavior and learning via neuroendocrine signaling. eLife 2019; 8:e50033. [PMID: 31674907 PMCID: PMC6884406 DOI: 10.7554/elife.50033] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/31/2019] [Indexed: 12/14/2022] Open
Abstract
The recognition of pathogens and subsequent activation of defense responses are critical for the survival of organisms. The nematode Caenorhabditis elegans recognizes pathogenic bacteria and elicits defense responses by activating immune pathways and pathogen avoidance. Here we show that chemosensation of phenazines produced by pathogenic Pseudomonas aeruginosa, which leads to rapid activation of DAF-7/TGF-β in ASJ neurons, is insufficient for the elicitation of pathogen avoidance behavior. Instead, intestinal infection and bloating of the lumen, which depend on the virulence of P. aeruginosa, regulates both pathogen avoidance and aversive learning by modulating not only the DAF-7/TGF-β pathway but also the G-protein coupled receptor NPR-1 pathway, which also controls aerotaxis behavior. Modulation of these neuroendocrine pathways by intestinal infection serves as a systemic feedback that enables animals to avoid virulent bacteria. These results reveal how feedback from the intestine during infection can modulate the behavior, learning, and microbial perception of the host.
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Affiliation(s)
- Jogender Singh
- Department of Molecular Microbiology & ImmunologyOregon Health & Science UniversityPortlandUnited States
| | - Alejandro Aballay
- Department of Molecular Microbiology & ImmunologyOregon Health & Science UniversityPortlandUnited States
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17
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Peng D, Luo X, Zhang N, Guo S, Zheng J, Chen L, Sun M. Small RNA-mediated Cry toxin silencing allows Bacillus thuringiensis to evade Caenorhabditis elegans avoidance behavioral defenses. Nucleic Acids Res 2019; 46:159-173. [PMID: 29069426 PMCID: PMC5758910 DOI: 10.1093/nar/gkx959] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 10/09/2017] [Indexed: 11/14/2022] Open
Abstract
Pathogen avoidance behavior protects animal hosts against microbial pathogens. Pathogens have evolved specific strategies during coevolution in response to such host defenses. However, these strategies for combatting host avoidance behavioral defenses remain poorly understood. Here, we used Caenorhabditis elegans and its bacterial pathogen Bacillus thuringiensis as a model and determined that small RNA (sRNA)-mediated Cry toxin silencing allowed pathogens to evade host avoidance behavioral defenses. The B. thuringiensis strain YBT-1518, which encodes three nematicidal cry genes, is highly toxic to C. elegans. However, the expression of the most potent toxin, Cry5Ba, was silenced in this strain when YBT-1518 was outside the host. Cry5Ba silencing was due to the sRNA BtsR1, which bound to the RBS site of the cry5Ba transcript via direct base pairing and inhibited Cry5Ba expression. Upon ingestion by C. elegans, Cry5Ba was expressed in vivo by strain YBT-1518. Cry5Ba silencing may allow B. thuringiensis to avoid nematode behavioral defenses and then express toxins once ingested to kill the host and gain a survival advantage. Our work describes a novel model of sRNA-mediated regulation to aid pathogens in combating host avoidance behavioral defenses.
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Affiliation(s)
- Donghai Peng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Xiaoxia Luo
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Ni Zhang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Suxia Guo
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Jinshui Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Ling Chen
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
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18
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Hoffman C, Aballay A. Role of neurons in the control of immune defense. Curr Opin Immunol 2019; 60:30-36. [PMID: 31117013 DOI: 10.1016/j.coi.2019.04.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/11/2019] [Accepted: 04/12/2019] [Indexed: 11/28/2022]
Abstract
Studies in recent years have strengthened the notion that neural mechanisms are involved in the control of immune responses. From initial studies that highlighted the vagus nerve control of inflammatory responses in vertebrates, many advances have been made, including the dissection of specific neural circuits that are involved in controlling immunity. Part of this has been facilitated by the use of a tractable model animal, Caenorhabditis elegans, in which individual neurons involved in sensing pathogens and controlling the immune response have been identified. Importantly, some of the underlying mechanisms involved in the neural control of immune pathways appear to be present in evolutionarily diverse species. This review focuses on some major developments in vertebrates and C. elegans, and how these discoveries may lead to advances in understanding neural-immune connections that govern inflammatory responses.
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Affiliation(s)
- Casandra Hoffman
- Molecular Microbiology and Immunology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, 6351 Richard Jones Hall, Mail Code: L220, Portland, OR 97239, United States
| | - Alejandro Aballay
- Molecular Microbiology and Immunology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, 6351 Richard Jones Hall, Mail Code: L220, Portland, OR 97239, United States.
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19
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Worthy SE, Rojas GL, Taylor CJ, Glater EE. Identification of Odor Blend Used by Caenorhabditis elegans for Pathogen Recognition. Chem Senses 2019; 43:169-180. [PMID: 29373666 PMCID: PMC6018680 DOI: 10.1093/chemse/bjy001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Animals have evolved specialized pathways to detect appropriate food sources and avoid harmful ones. Caenorhabditis elegans can distinguish among the odors of various species of bacteria, its major food source, but little is known about what specific chemical cue or combination of chemical cues C. elegans uses to detect and recognize different microbes. Here, we examine the strong innate attraction of C. elegans for the odor of the pathogenic bacterium, Serratia marcescens. This initial attraction likely facilitates ingestion and infection of the C. elegans host. Using solid-phase microextraction and gas chromatography coupled with mass spectrometry, we identify 5 volatile odors released by S. marcescens and identify those that are attractive to C. elegans. We use genetic methods to show that the amphid chemosensory neuron, AWCON, senses both S. marcescens-released 2-butanone and acetone and drives attraction to S. marcescens. In C. elegans, pairing a single odorant with food deprivation results in a reduced attractive response for that specific odor. We find that pairing the natural odor of S. marcescens with food deprivation results in a reduced attraction for the natural odor of S. marcescens and a similar reduced attraction for the synthetic blend of acetone and 2-butanone. This result indicates that only 2 odorants represent the more complex odor bouquet of S. marcescens. Although bacterial-released volatiles have long been known to be attractive to C. elegans, this study defines for the first time specific volatile cues that represent a particular bacterium to C. elegans.
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Affiliation(s)
| | - German L Rojas
- Department of Neuroscience, Pomona College, Claremont, CA, USA
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20
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Casadei E, Salinas I. Comparative models for human nasal infections and immunity. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2019; 92:212-222. [PMID: 30513304 PMCID: PMC7102639 DOI: 10.1016/j.dci.2018.11.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/30/2018] [Accepted: 11/30/2018] [Indexed: 05/09/2023]
Abstract
The human olfactory system is a mucosal surface and a major portal of entry for respiratory and neurotropic pathogens into the body. Understanding how the human nasopharynx-associated lymphoid tissue (NALT) halts the progression of pathogens into the lower respiratory tract or the central nervous system is key for developing effective cures. Although traditionally mice have been used as the gold-standard model for the study of human nasal diseases, mouse models present important caveats due to major anatomical and functional differences of the human and murine olfactory system and NALT. We summarize the NALT anatomy of different animal groups that have thus far been used to study host-pathogen interactions at the olfactory mucosa and to test nasal vaccines. The goal of this review is to highlight the strengths and limitations of each animal model of nasal immunity and to identify the areas of research that require further investigation to advance human health.
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Affiliation(s)
- Elisa Casadei
- University of New Mexico, Department of Biology, Center for Evolutionary and Theoretical Immunology (CETI), Albuquerque, NM, USA.
| | - Irene Salinas
- University of New Mexico, Department of Biology, Center for Evolutionary and Theoretical Immunology (CETI), Albuquerque, NM, USA
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21
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Khan F, Jain S, Oloketuyi SF. Bacteria and bacterial products: Foe and friends to Caenorhabditis elegans. Microbiol Res 2018; 215:102-113. [DOI: 10.1016/j.micres.2018.06.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/11/2018] [Accepted: 06/24/2018] [Indexed: 02/07/2023]
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22
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Nematodes avoid and are killed by Bacillus mycoides-produced styrene. J Invertebr Pathol 2018; 159:129-136. [PMID: 30268676 DOI: 10.1016/j.jip.2018.09.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 09/21/2018] [Accepted: 09/26/2018] [Indexed: 01/20/2023]
Abstract
Root-knot nematodes are obligate parasites that feed on plant roots and cause serious crop losses worldwide. Bacillus species (Bacilliaceae) can produce nematicidal metabolites and have shown good potential for biological control of nematodes. In this study, Bacillus mycoides strain R2 isolated from rhizosphere soil of tomato plants exhibited high nematicidal activity against the free-living nematode Caenorhabditis elegans and the root-knot nematode Meloidogyne incognita. In a pot experiment, control efficiency of B. mycoides R2 on M. incognita was as high as 90.94%. The nematicidal compound was isolated and identified as styrene. The median lethal concentration of styrene against M. incognita was 4.55 μg/ml (m/v). The volatile styrene caused avoidance and killed nematodes primarily by the olfactory neuron and G protein signal pathway. C. elegans detected styrene with the AWB neuron; the signal was then transmitted to the downstream G protein coupled receptors CHE-3, DOP-3, and STR-2. Then signal activated G protein GPA-3 and GPA-7. The signal was then transmitted to ion channels (CNGs channel and TRPV channel), causing calcium ion internal flow and a stress response towards the increased concentration of intracellular calcium. Styrene should be registered as a nematode repellent and biocontrol agent for protection of crops against root-knot nematode attack.
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23
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Worthy SE, Haynes L, Chambers M, Bethune D, Kan E, Chung K, Ota R, Taylor CJ, Glater EE. Identification of attractive odorants released by preferred bacterial food found in the natural habitats of C. elegans. PLoS One 2018; 13:e0201158. [PMID: 30036396 PMCID: PMC6056031 DOI: 10.1371/journal.pone.0201158] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 07/10/2018] [Indexed: 01/26/2023] Open
Abstract
Food choice is critical for survival because organisms must choose food that is edible and nutritious and avoid pathogenic food. Many organisms, including the nematode C. elegans, use olfaction to detect and distinguish among food sources. C. elegans exhibits innate preferences for the odors of different bacterial species. However, little is known about the preferences of C. elegans for bacterial strains isolated from their natural environment as well as the attractive volatile compounds released by preferred natural bacteria isolates. We tested food odor preferences of C. elegans for non-pathogenic bacteria found in their natural habitats. We found that C. elegans showed a preference for the odor of six of the eight tested bacterial isolates over its standard food source, E. coli HB101. Using solid-phase microextraction and gas chromatography coupled with mass spectrometry, we found that four of six attractive bacterial isolates (Alcaligenes sp. JUb4, Providenica sp. JUb5, Providencia sp. JUb39, and Flavobacteria sp. JUb43) released isoamyl alcohol, a well-studied C. elegans attractant, while both non-attractive isolates (Raoultella sp. JUb38 and Acinetobacter sp. JUb68) released very low or non-detectable amounts of isoamyl alcohol. In conclusion, we find that isoamyl alcohol is likely an ethologically relevant odor that is released by some attractive bacterial isolates in the natural environment of C. elegans.
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Affiliation(s)
- Soleil E. Worthy
- Department of Chemistry, Pomona College, Claremont, California, United States of America
| | - Lillian Haynes
- Department of Biology, Harvey Mudd College, Claremont, California, United States of America
| | - Melissa Chambers
- Department of Neuroscience, Pomona College, Claremont, California, United States of America
| | - Danika Bethune
- Department of Neuroscience, Pomona College, Claremont, California, United States of America
| | - Emily Kan
- Department of Neuroscience, Pomona College, Claremont, California, United States of America
| | - Kevin Chung
- Department of Neuroscience, Pomona College, Claremont, California, United States of America
| | - Ryan Ota
- Department of Neuroscience, Pomona College, Claremont, California, United States of America
| | - Charles J. Taylor
- Department of Chemistry, Pomona College, Claremont, California, United States of America
| | - Elizabeth E. Glater
- Department of Neuroscience, Pomona College, Claremont, California, United States of America
- * E-mail:
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24
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Hedrick SM. Understanding Immunity through the Lens of Disease Ecology. Trends Immunol 2017; 38:888-903. [PMID: 28882454 DOI: 10.1016/j.it.2017.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 07/26/2017] [Accepted: 08/01/2017] [Indexed: 10/25/2022]
Abstract
As we describe the immune system in ever more exquisite detail, we might find that no matter how successful, this approach will not be sufficient to understand the spread of infectious agents, their susceptibility to vaccine therapy, and human disease resistance. Compared with the strict reductionism practiced as a means of characterizing most biological processes, I propose that the progression and outcome of disease-causing host-parasite interactions will be more clearly understood through a focus on disease ecology.
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Affiliation(s)
- Stephen M Hedrick
- Departments of Molecular Biology and Cellular and Molecular Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
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25
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Schulenburg H, Félix MA. The Natural Biotic Environment of Caenorhabditis elegans. Genetics 2017; 206:55-86. [PMID: 28476862 PMCID: PMC5419493 DOI: 10.1534/genetics.116.195511] [Citation(s) in RCA: 254] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 02/28/2017] [Indexed: 01/05/2023] Open
Abstract
Organisms evolve in response to their natural environment. Consideration of natural ecological parameters are thus of key importance for our understanding of an organism's biology. Curiously, the natural ecology of the model species Caenorhabditis elegans has long been neglected, even though this nematode has become one of the most intensively studied models in biological research. This lack of interest changed ∼10 yr ago. Since then, an increasing number of studies have focused on the nematode's natural ecology. Yet many unknowns still remain. Here, we provide an overview of the currently available information on the natural environment of C. elegans We focus on the biotic environment, which is usually less predictable and thus can create high selective constraints that are likely to have had a strong impact on C. elegans evolution. This nematode is particularly abundant in microbe-rich environments, especially rotting plant matter such as decomposing fruits and stems. In this environment, it is part of a complex interaction network, which is particularly shaped by a species-rich microbial community. These microbes can be food, part of a beneficial gut microbiome, parasites and pathogens, and possibly competitors. C. elegans is additionally confronted with predators; it interacts with vector organisms that facilitate dispersal to new habitats, and also with competitors for similar food environments, including competitors from congeneric and also the same species. Full appreciation of this nematode's biology warrants further exploration of its natural environment and subsequent integration of this information into the well-established laboratory-based research approaches.
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Affiliation(s)
- Hinrich Schulenburg
- Zoological Institute, Christian-Albrechts Universitaet zu Kiel, 24098 Kiel, Germany
| | - Marie-Anne Félix
- Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, École Normale Supérieure, L'université de Recherche Paris Sciences et Lettres, 75005, France
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26
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Natural Genetic Variation in the Caenorhabditis elegans Response to Pseudomonas aeruginosa. G3-GENES GENOMES GENETICS 2017; 7:1137-1147. [PMID: 28179390 PMCID: PMC5386862 DOI: 10.1534/g3.117.039057] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Caenorhabditis elegans responds to pathogenic microorganisms by activating its innate immune system, which consists of physical barriers, behavioral responses, and microbial killing mechanisms. We examined whether natural variation plays a role in the response of C. elegans to Pseudomonas aeruginosa using two C. elegans strains that carry the same allele of npr-1, a gene that encodes a G-protein-coupled receptor related to mammalian neuropeptide Y receptors, but that differ in their genetic backgrounds. Strains carrying an allele for the NPR-1 215F isoform have been shown to exhibit lack of pathogen avoidance behavior and deficient immune response toward P. aeruginosa relative to the wild-type (N2) strain. We found that the wild isolate from Germany RC301, which carries the allele for NPR-1 215F, shows an enhanced resistance to P. aeruginosa infection when compared with strain DA650, which also carries NPR-1 215F but in an N2 background. Using a whole-genome sequencing single-nucleotide polymorphism (WGS-SNP) mapping strategy, we determined that the resistance to P. aeruginosa infection maps to a region on chromosome V. Furthermore, we demonstrated that the mechanism for the enhanced resistance to P. aeruginosa infection relies exclusively on strong P. aeruginosa avoidance behavior, and does not involve the main immune, stress, and lifespan extension pathways in C. elegans. Our findings underscore the importance of pathogen-specific behavioral immune defense in the wild, which seems to be favored over the more energy-costly mechanism of activation of physiological cellular defenses.
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27
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Khanna A, Kumar J, Vargas MA, Barrett L, Katewa S, Li P, McCloskey T, Sharma A, Naudé N, Nelson C, Brem R, Killilea DW, Mooney SD, Gill M, Kapahi P. A genome-wide screen of bacterial mutants that enhance dauer formation in C. elegans. Sci Rep 2016; 6:38764. [PMID: 27958277 PMCID: PMC5153853 DOI: 10.1038/srep38764] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 11/10/2016] [Indexed: 11/09/2022] Open
Abstract
Molecular pathways involved in dauer formation, an alternate larval stage that allows Caenorhabditis elegans to survive adverse environmental conditions during development, also modulate longevity and metabolism. The decision to proceed with reproductive development or undergo diapause depends on food abundance, population density, and temperature. In recent years, the chemical identities of pheromone signals that modulate dauer entry have been characterized. However, signals derived from bacteria, the major source of nutrients for C. elegans, remain poorly characterized. To systematically identify bacterial components that influence dauer formation and aging in C. elegans, we utilized the individual gene deletion mutants in E. coli (K12). We identified 56 diverse E. coli deletion mutants that enhance dauer formation in an insulin-like receptor mutant (daf-2) background. We describe the mechanism of action of a bacterial mutant cyaA, that is defective in the production of cyclic AMP, which extends lifespan and enhances dauer formation through the modulation of TGF-β (daf-7) signaling in C. elegans. Our results demonstrate the importance of bacterial components in influencing developmental decisions and lifespan in C. elegans. Furthermore, we demonstrate that C. elegans is a useful model to study bacterial-host interactions.
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Affiliation(s)
- Amit Khanna
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, USA
| | - Jitendra Kumar
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, USA
| | - Misha A Vargas
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, USA
| | - LaKisha Barrett
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, USA
| | - Subhash Katewa
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, USA
| | - Patrick Li
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, USA
| | - Tom McCloskey
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, USA
| | - Amit Sharma
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, USA
| | - Nicole Naudé
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, USA
| | | | - Rachel Brem
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, USA
| | - David W Killilea
- Nutrition &Metabolism Center, Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA, USA
| | - Sean D Mooney
- Department of Biomedical Informatics and Medical Education, University of Washington, Seattle, Washington 98195, USA
| | - Matthew Gill
- Department of Metabolism &Aging, The Scripps Research Institute- Scripps Florida, Jupiter, Florida, 33458, USA
| | - Pankaj Kapahi
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, USA
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28
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Zhang C, Zhao N, Chen Y, Zhang D, Yan J, Zou W, Zhang K, Huang X. The Signaling Pathway of Caenorhabditis elegans Mediates Chemotaxis Response to the Attractant 2-Heptanone in a Trojan Horse-like Pathogenesis. J Biol Chem 2016; 291:23618-23627. [PMID: 27660389 DOI: 10.1074/jbc.m116.741132] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Indexed: 11/06/2022] Open
Abstract
The nematode Caenorhabditis elegans exhibits behavioral responses to a wide range of odorants associated with food and pathogens. A previous study described a Trojan Horse-like strategy of pathogenesis whereby the bacterium Bacillus nematocida B16 emits the volatile organic compound 2-heptanone to trap C. elegans for successful infection. Here, we further explored the receptor for 2-heptanone as well as the pathway involved in signal transduction in C. elegans Our experiments showed that 2-heptanone sensing depended on the function of AWC neurons and a GPCR encoded by str-2 Consistent with the above observation, the HEK293 cells expressing STR-2 on their surfaces showed a transient elevation in intracellular Ca2+ levels after 2-heptanone applications. After combining the assays of RNA interference and gene mutants, we also identified the Gα subunits and their downstream components in the olfactory signal cascade that are necessary for responding to 2-heptanone, including Gα subunits of egl-30 and gpa-3, phospholipase C of plc-1and egl-8, and the calcium channel of cmk-1 and cal-1. Our work demonstrates for the first time that an integrated signaling pathway for 2-heptanone response in C. elegans involves recognition by GPCR STR-2, activation by Gα subunits of egl-30/gpa-3 and transfer to the PLC pathway, indicating that a potentially novel olfactory pathway exists in AWC neurons. Meanwhile, since 2-heptanone, a metabolite from the pathogenic bacterium B. nematocida B16, can be sensed by C. elegans and thus strongly attract its host, our current work also suggested coevolution between the pathogenic microorganism and the chemosensory system in C. elegans.
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Affiliation(s)
- Chunmei Zhang
- From the State Key Lab for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan 650091, China
| | - Ninghui Zhao
- Neurosurgery of the Second Hospital affiliated with Kunming Medical University, Kunming 650101, China, and
| | - Yao Chen
- From the State Key Lab for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan 650091, China
| | - Donghua Zhang
- From the State Key Lab for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan 650091, China
| | - Jinyuan Yan
- Center Laboratory of the Second Hospital affiliated with Kunming Medical University, Kunming 650101, China
| | - Wei Zou
- From the State Key Lab for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan 650091, China
| | - Keqin Zhang
- From the State Key Lab for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan 650091, China
| | - Xiaowei Huang
- From the State Key Lab for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan 650091, China,
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Ballestriero F, Nappi J, Zampi G, Bazzicalupo P, Di Schiavi E, Egan S. Caenorhabditis elegans employs innate and learned aversion in response to bacterial toxic metabolites tambjamine and violacein. Sci Rep 2016; 6:29284. [PMID: 27384057 PMCID: PMC4935850 DOI: 10.1038/srep29284] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 06/14/2016] [Indexed: 12/19/2022] Open
Abstract
Bacteriovorus eukaryotes such as nematodes are one of the major natural predators of bacteria. In their defense bacteria have evolved a number of strategies to avoid predation, including the production of deterrent or toxic metabolites, however little is known regarding the response of predators towards such bacterial defenses. Here we use the nematode C. elegans as a model to study a predators’ behavioral response towards two toxic bacterial metabolites, tambjamine YP1 and violacein. We found that C. elegans displays an innate avoidance behavior towards tambjamine YP1, however requires previous exposure to violacein before learning to avoid this metabolite. The learned avoidance of violacein is specific, reversible, is mediated via the nematode olfactory apparatus (aversive olfactory learning) and is reduced in the absence of the neurotransmitter serotonin. These multiple strategies to evade bacterial toxic metabolites represent a valuable behavioral adaptation allowing bacteriovorus predators to distinguish between good and bad food sources, thus contributing to the understanding of microbial predator-prey interactions.
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Affiliation(s)
- Francesco Ballestriero
- School of Biological, Earth and Environmental Science and Centre for Marine Bio-Innovation, University of New South Wales, Australia
| | - Jadranka Nappi
- School of Biological, Earth and Environmental Science and Centre for Marine Bio-Innovation, University of New South Wales, Australia
| | - Giuseppina Zampi
- Institute of Biosciences and BioResources, National Research Council, Naples, Italy
| | - Paolo Bazzicalupo
- Institute of Biosciences and BioResources, National Research Council, Naples, Italy.,Institute of Genetics and Biophysics, National Research Council, Naples, Italy
| | - Elia Di Schiavi
- Institute of Biosciences and BioResources, National Research Council, Naples, Italy.,Institute of Genetics and Biophysics, National Research Council, Naples, Italy
| | - Suhelen Egan
- School of Biological, Earth and Environmental Science and Centre for Marine Bio-Innovation, University of New South Wales, Australia
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30
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Bracho OR, Manchery C, Haskell EC, Blanar CA, Smith RP. Circumvention of Learning Increases Intoxication Efficacy of Nematicidal Engineered Bacteria. ACS Synth Biol 2016; 5:241-9. [PMID: 26692340 DOI: 10.1021/acssynbio.5b00192] [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] [Indexed: 01/01/2023]
Abstract
Synthetic biology holds promise to engineer systems to treat diseases. One critical, yet underexplored, facet of designing such systems is the interplay between the system and the pathogen. Understanding this interplay may be critical to increasing efficacy and overcoming resistance against the system. Using the principles of synthetic biology, we engineer a strain of Escherichia coli to attract and intoxicate the nematode Caenorhabditis elegans. Our bacteria are engineered with a toxin module, which intoxicates the nematode upon ingestion, and an attraction module, which serves to attract and increase the feeding rate of the nematodes. When independently implemented, these modules successfully intoxicate and attract the worms, respectively. However, in combination, the efficacy of our bacteria is significantly reduced due to aversive associative learning in C. elegans. Guided by mathematical modeling, we dynamically regulate module induction to increase intoxication by circumventing learning. Our results detail the creation of a novel nematicidal bacterium that may have application against nematodes, unravel unique constraints on circuit dynamics that are governed by C. elegans physiology, and add to the growing list of design and implementation considerations associated with synthetic biology.
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Affiliation(s)
- Olena R. Bracho
- Department
of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale, Florida 33314, United States
| | - Cyril Manchery
- Department
of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale, Florida 33314, United States
| | - Evan C. Haskell
- Department
of Mathematics, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale, Florida 33314, United States
| | - Christopher A. Blanar
- Department
of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale, Florida 33314, United States
| | - Robert P. Smith
- Department
of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale, Florida 33314, United States
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31
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Lee J, Kwon G, Lim YH. Elucidating the Mechanism of Weissella-dependent Lifespan Extension in Caenorhabditis elegans. Sci Rep 2015; 5:17128. [PMID: 26601690 PMCID: PMC4658530 DOI: 10.1038/srep17128] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 10/26/2015] [Indexed: 11/09/2022] Open
Abstract
The mechanism whereby lactic acid bacteria extend the lifespan of Caenorhabditis elegans has previously been elucidated. However, the role of Weissella species has yet not been studied. We show that Weissella koreensis and Weissella cibaria significantly (p < 0.05) extend the lifespan of C. elegans compared with Escherichia coli OP50 and induce the expression of several genes related to lifespan extension (daf-16, aak-2, jnk-1, sod-3 and hif-1). Oral administration of Weissella altered reactive oxygen species (ROS) production and lowered the accumulation of lipofuscin and increased locomotor activity (which translates to a delay in ageing). Moreover, Weissella-fed C. elegans had decreased body sizes, brood sizes, ATP levels and pharyngeal pumping rates compared with E. coli OP50-fed worms. Furthermore, mutations in sod-3, hif-1 or skn-1 did not alter lifespan extension compared with wild-type C. elegans. However, C. elegans failed to display lifespan extension in loss-of-function mutants of daf-16, aak-2 and jnk-1, which highlights the potential role of these genes in Weissella-induced longevity in C. elegans. Weissella species extend C. elegans lifespan by activating DAF-16 via the c-Jun N-terminal kinase (JNK) pathway, which is related to stress response, and the AMP-activated protein kinase (AMPK)-pathway that is activated by dietary restriction.
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Affiliation(s)
- Jiyun Lee
- Department of Public Health Science (Brain Korea 21 PLUS program), Graduate School, Korea University, Seoul 136-701, Republic of Korea
| | - Gayeung Kwon
- Department of Public Health Science (Brain Korea 21 PLUS program), Graduate School, Korea University, Seoul 136-701, Republic of Korea
| | - Young-Hee Lim
- Department of Public Health Science (Brain Korea 21 PLUS program), Graduate School, Korea University, Seoul 136-701, Republic of Korea.,School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, Republic of Korea.,Department of Laboratory Medicine, Korea University Guro Hospital, Seoul, Republic of Korea
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32
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Yu L, Yan X, Ye C, Zhao H, Chen X, Hu F, Li H. Bacterial Respiration and Growth Rates Affect the Feeding Preferences, Brood Size and Lifespan of Caenorhabditis elegans. PLoS One 2015. [PMID: 26222828 PMCID: PMC4519269 DOI: 10.1371/journal.pone.0134401] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Bacteria serve as live food and nutrients for bacterial-feeding nematodes (BFNs) in soils, and influence nematodes behavior and physiology through their metabolism. Five bacterial taxa (Bacillus amyloliquefaciens JX1, Variovorax sp. JX14, Bacillus megaterium JX15, Pseudomonas fluorescens Y1 and Escherichia coli OP50) and the typical BFN Caenorhabditis elegans were selected to study the effects of bacterial respiration and growth rates on the feeding preferences, brood size and lifespan of nematodes. P. fluorescens Y1 and E. coli OP50 were found to be more active, with high respiration and rapid growth, whereas B. amyloliquefaciens JX1 and B. megaterium JX15 were inactive. The nematode C. elegans preferred active P. fluorescens Y1 and E. coli OP50 obviously. Furthermore, worms that fed on these two active bacteria produced more offspring but had shorter lifespan, while inactive and less preferred bacteria had increased nematodes lifespan and decreased the brood size. Based on these results, we propose that the bacterial activity may influence the behavior and life traits of C. elegans in the following ways: (1) active bacteria reproduce rapidly and emit high levels of CO2 attracting C. elegans; (2) these active bacteria use more resources in the nematodes’ gut to sustain their survival and reproduction, thereby reducing the worm's lifespan; (3) inactive bacteria may provide less food for worms than active bacteria, thus increasing nematodes lifespan but decreasing their fertility. Nematodes generally require a balance between their preferred foods and beneficial foods, only preferred food may not be beneficial for nematodes.
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Affiliation(s)
- Li Yu
- Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095, People’s Republic of China
| | - Xiaomei Yan
- Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095, People’s Republic of China
| | - Chenglong Ye
- Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095, People’s Republic of China
| | - Haiyan Zhao
- College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095, People’s Republic of China
| | - Xiaoyun Chen
- Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095, People’s Republic of China
| | - Feng Hu
- Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095, People’s Republic of China
| | - Huixin Li
- Soil Ecology Lab, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095, People’s Republic of China
- * E-mail:
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33
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Nandi M, Selin C, Brassinga AKC, Belmonte MF, Fernando WGD, Loewen PC, de Kievit TR. Pyrrolnitrin and Hydrogen Cyanide Production by Pseudomonas chlororaphis Strain PA23 Exhibits Nematicidal and Repellent Activity against Caenorhabditis elegans. PLoS One 2015; 10:e0123184. [PMID: 25901993 PMCID: PMC4406715 DOI: 10.1371/journal.pone.0123184] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 03/02/2015] [Indexed: 11/19/2022] Open
Abstract
Pseudomonas chlororaphis strain PA23 is a biocontrol agent able to suppress growth of the fungal pathogen Sclerotinia sclerotiorum. This bacterium produces an arsenal of exometabolites including pyrrolnitrin (PRN), phenazine (PHZ), hydrogen cyanide (HCN), and degradative enzymes. Production of these compounds is controlled at both the transcriptional and posttranscriptional levels by the Gac-Rsm system, RpoS, PsrA, and the Phz quorum-sensing system. Beyond pathogen-suppression, the success of a biocontrol agent is dependent upon its ability to establish itself in the environment where predation by bacterivorous organisms, including nematodes, may threaten persistence. The focus of this study was to investigate whether PA23 is able to resist grazing by Caenorhabditis elegans and to define the role played by exoproducts in the bacterial-nematode interaction. We discovered that both PRN and HCN contribute to fast- and slow-killing of C. elegans. HCN is well-established as having lethal effects on C. elegans; however, PRN has not been reported to be nematicidal. Exposure of L4 stage nematodes to purified PRN reduced nematode viability in a dose-dependent fashion and led to reduced hatching of eggs laid by gravid adults. Because bacterial metabolites can act as chemoattractants or repellents, we analyzed whether PA23 exhibited attractant or repulsive properties towards C. elegans. Both PRN and HCN were found to be potent repellents. Next we investigated whether the presence of C. elegans would elicit changes in PA23 gene activity. Co-culturing the two organisms increased expression of a number of genes associated with biocontrol, including phzA, hcnA, phzR, phzI, rpoS and gacS. Exoproduct analysis showed that PHZ and autoinducer signals were upregulated, consistent with the gene expression profiles. Collectively, these findings indicate that PA23 is able to sense the presence of C. elegans and it is able to both repel and kill the nematodes, which should facilitate environmental persistence and ultimately biocontrol.
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Affiliation(s)
- Munmun Nandi
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Carrie Selin
- Department of Plant Science University of Manitoba, Winnipeg, Manitoba, Canada
| | | | - Mark F. Belmonte
- Department of Biological Sciences University of Manitoba, Winnipeg, Manitoba, Canada
| | | | - Peter C. Loewen
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Teresa R. de Kievit
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
- * E-mail:
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34
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35
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Meisel JD, Panda O, Mahanti P, Schroeder FC, Kim DH. Chemosensation of bacterial secondary metabolites modulates neuroendocrine signaling and behavior of C. elegans. Cell 2015; 159:267-80. [PMID: 25303524 DOI: 10.1016/j.cell.2014.09.011] [Citation(s) in RCA: 199] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 07/03/2014] [Accepted: 09/03/2014] [Indexed: 11/30/2022]
Abstract
Discrimination between pathogenic and beneficial microbes is essential for host organism immunity and homeostasis. Here, we show that chemosensory detection of two secondary metabolites produced by Pseudomonas aeruginosa modulates a neuroendocrine signaling pathway that promotes avoidance behavior in the simple animal host Caenorhabditis elegans. Secondary metabolites phenazine-1-carboxamide and pyochelin activate a G-protein-signaling pathway in the ASJ chemosensory neuron pair that induces expression of the neuromodulator DAF-7/TGF-β. DAF-7, in turn, activates a canonical TGF-β signaling pathway in adjacent interneurons to modulate aerotaxis behavior and promote avoidance of pathogenic P. aeruginosa. Our data provide a chemical, genetic, and neuronal basis for how the behavior and physiology of a simple animal host can be modified by the microbial environment and suggest that secondary metabolites produced by microbes may provide environmental cues that contribute to pathogen recognition and host survival.
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Affiliation(s)
- Joshua D Meisel
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Oishika Panda
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Parag Mahanti
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Frank C Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Dennis H Kim
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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36
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López Hernández Y, Yero D, Pinos-Rodríguez JM, Gibert I. Animals devoid of pulmonary system as infection models in the study of lung bacterial pathogens. Front Microbiol 2015; 6:38. [PMID: 25699030 PMCID: PMC4316775 DOI: 10.3389/fmicb.2015.00038] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 01/12/2015] [Indexed: 01/15/2023] Open
Abstract
Biological disease models can be difficult and costly to develop and use on a routine basis. Particularly, in vivo lung infection models performed to study lung pathologies use to be laborious, demand a great time and commonly are associated with ethical issues. When infections in experimental animals are used, they need to be refined, defined, and validated for their intended purpose. Therefore, alternative and easy to handle models of experimental infections are still needed to test the virulence of bacterial lung pathogens. Because non-mammalian models have less ethical and cost constraints as a subjects for experimentation, in some cases would be appropriated to include these models as valuable tools to explore host-pathogen interactions. Numerous scientific data have been argued to the more extensive use of several kinds of alternative models, such as, the vertebrate zebrafish (Danio rerio), and non-vertebrate insects and nematodes (e.g., Caenorhabditis elegans) in the study of diverse infectious agents that affect humans. Here, we review the use of these vertebrate and non-vertebrate models in the study of bacterial agents, which are considered the principal causes of lung injury. Curiously none of these animals have a respiratory system as in air-breathing vertebrates, where respiration takes place in lungs. Despite this fact, with the present review we sought to provide elements in favor of the use of these alternative animal models of infection to reveal the molecular signatures of host-pathogen interactions.
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Affiliation(s)
- Yamilé López Hernández
- Centro de Biociencias, Universidad Autónoma de San Luis Potosí San Luis de Potosí, Mexico
| | - Daniel Yero
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Juan M Pinos-Rodríguez
- Centro de Biociencias, Universidad Autónoma de San Luis Potosí San Luis de Potosí, Mexico
| | - Isidre Gibert
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
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37
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Werner KM, Perez LJ, Ghosh R, Semmelhack MF, Bassler BL. Caenorhabditis elegans recognizes a bacterial quorum-sensing signal molecule through the AWCON neuron. J Biol Chem 2014; 289:26566-26573. [PMID: 25092291 PMCID: PMC4176233 DOI: 10.1074/jbc.m114.573832] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Revised: 07/11/2014] [Indexed: 11/06/2022] Open
Abstract
In a process known as quorum sensing, bacteria use chemicals called autoinducers for cell-cell communication. Population-wide detection of autoinducers enables bacteria to orchestrate collective behaviors. In the animal kingdom detection of chemicals is vital for success in locating food, finding hosts, and avoiding predators. This behavior, termed chemotaxis, is especially well studied in the nematode Caenorhabditis elegans. Here we demonstrate that the Vibrio cholerae autoinducer (S)-3-hydroxytridecan-4-one, termed CAI-1, influences chemotaxis in C. elegans. C. elegans prefers V. cholerae that produces CAI-1 over a V. cholerae mutant defective for CAI-1 production. The position of the CAI-1 ketone moiety is the key feature driving CAI-1-directed nematode behavior. CAI-1 is detected by the C. elegans amphid sensory neuron AWC(ON). Laser ablation of the AWC(ON) cell, but not other amphid sensory neurons, abolished chemoattraction to CAI-1. These analyses define the structural features of a bacterial-produced signal and the nematode chemosensory neuron that permit cross-kingdom interaction.
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Affiliation(s)
- Kristen M Werner
- Department of Molecular Biology and Princeton University, Princeton, New Jersey 08544
| | - Lark J Perez
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, New Jersey 08028
| | - Rajarshi Ghosh
- Department of Pediatrics-Oncology, Baylor College of Medicine, Houston, Texas 77030, and
| | | | - Bonnie L Bassler
- Department of Molecular Biology and Princeton University, Princeton, New Jersey 08544; Howard Hughes Medical Institute, Chevy Chase, Maryland 20815.
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38
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Meisel JD, Kim DH. Behavioral avoidance of pathogenic bacteria by Caenorhabditis elegans. Trends Immunol 2014; 35:465-70. [PMID: 25240986 DOI: 10.1016/j.it.2014.08.008] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 08/25/2014] [Accepted: 08/25/2014] [Indexed: 12/25/2022]
Abstract
The simple animal host Caenorhabditis elegans utilizes its nervous system to respond to diverse microbial cues, and can engage in a protective behavioral avoidance response to environmental pathogens. This behavior bears hallmarks of an immune response, with sensors and recognition systems that trigger a protective response following a learning experience. Neuronal circuits required for aversive learning have been defined, revealing conserved signaling modules with dual roles in immunity and neuronal responses to pathogenic bacteria. Identification of natural polymorphisms that modulate avoidance behavior has enabled an improved understanding of host-microbe interactions at the molecular level. We review here these findings and discuss how the microbial cues and host responses defined in C. elegans may provide insight into evolutionarily diverse host-microbe interactions.
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Affiliation(s)
- Joshua D Meisel
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Dennis H Kim
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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39
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Tahseen Q, Clark IM. Attraction and preference of bacteriophagous and plant-parasitic nematodes towards different types of soil bacteria. J NAT HIST 2014. [DOI: 10.1080/00222933.2013.873088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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40
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Yuen GJ, Ausubel FM. Enterococcus infection biology: lessons from invertebrate host models. J Microbiol 2014; 52:200-10. [PMID: 24585051 PMCID: PMC4556283 DOI: 10.1007/s12275-014-4011-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 01/21/2014] [Indexed: 12/29/2022]
Abstract
The enterococci are commensals of the gastrointestinal tract of many metazoans, from insects to humans. While they normally do not cause disease in the intestine, they can become pathogenic when they infect sites outside of the gut. Recently, the enterococci have become important nosocomial pathogens, with the majority of human enterococcal infections caused by two species, Enterococcus faecalis and Enterococcus faecium. Studies using invertebrate infection models have revealed insights into the biology of enterococcal infections, as well as general principles underlying host innate immune defense. This review highlights recent findings on Enterococcus infection biology from two invertebrate infection models, the greater wax moth Galleria mellonella and the free-living bacteriovorous nematode Caenorhabditis elegans.
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Affiliation(s)
- Grace J. Yuen
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Frederick M. Ausubel
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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41
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The olfactory signal transduction for attractive odorants in Caenorhabditis elegans. Biotechnol Adv 2014; 32:290-5. [DOI: 10.1016/j.biotechadv.2013.10.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 10/14/2013] [Accepted: 10/28/2013] [Indexed: 11/20/2022]
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42
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Activation of olfactory receptors on mouse pulmonary macrophages promotes monocyte chemotactic protein-1 production. PLoS One 2013; 8:e80148. [PMID: 24278251 PMCID: PMC3836993 DOI: 10.1371/journal.pone.0080148] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 09/29/2013] [Indexed: 12/31/2022] Open
Abstract
Background Emerging evidence suggests that non-olfactory tissues and cells can express olfactory receptors (ORs), however, the exact function of ectopic OR expression remains unknown. We have previously shown in mouse models that a unique cooperation between interferon-γ (IFN-γ) and lipopolysaccharide (LPS) drives the activation of pulmonary macrophages and leads to the induction of pathogenic responses in the respiratory tract. Further, through gene array studies, we have shown that activation of macrophages by these molecules results in the selective expression of a number of ORs. In this study, we validated the expression of these ORs in mouse airway and pulmonary macrophages in response to IFN-γ and LPS (γ/LPS) stimulation, and further explored the effect of odorant stimulation on macrophage function. Methodology/Principal Findings OR expression in airway and pulmonary macrophages in response to IFN-γ, LPS or γ/LPS treatments was assessed by microarray and validated by q-PCR. OR expression (e.g. OR622) on macrophages was confirmed by visualization in immunofluoresence assays. Functional responses to odorants were assessed by quantifying inflammatory cytokine and chemokine expression using q-PCR and cell migration was assessed by a modified Boyden chamber migration assay. Our results demonstrate that eight ORs are expressed at basal levels in both airway and pulmonary macrophages, and that γ/LPS stimulation cooperatively increased this expression. Pulmonary macrophages exposed to the combined treatment of γ/LPS+octanal (an odorant) exhibited a 3-fold increase in MCP-1 protein production, compared to cells treated with γ/LPS alone. Supernatants from γ/LPS+octanal exposed macrophages also increased macrophage migration in vitro. Conclusions/Significance Eight different ORs are expressed at basal levels in pulmonary macrophages and expression is upregulated by the synergistic action of γ/LPS. Octanal stimulation further increased MCP-1 production and the motility of macrophages. Our results suggest that ORs may mediate macrophage function by regulating MCP-1 production and cell migration.
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Sonowal R, Nandimath K, Kulkarni SS, Koushika SP, Nanjundiah V, Mahadevan S. Hydrolysis of aromatic β-glucosides by non-pathogenic bacteria confers a chemical weapon against predators. Proc Biol Sci 2013; 280:20130721. [PMID: 23677347 PMCID: PMC3673059 DOI: 10.1098/rspb.2013.0721] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 04/18/2013] [Indexed: 11/12/2022] Open
Abstract
Bacteria present in natural environments such as soil have evolved multiple strategies to escape predation. We report that natural isolates of Enterobacteriaceae that actively hydrolyze plant-derived aromatic β-glucosides such as salicin, arbutin and esculin, are able to avoid predation by the bacteriovorous amoeba Dictyostelium discoideum and nematodes of multiple genera belonging to the family Rhabditidae. This advantage can be observed under laboratory culture conditions as well as in the soil environment. The aglycone moiety released by the hydrolysis of β-glucosides is toxic to predators and acts via the dopaminergic receptor Dop-1 in the case of Caenorhabditis elegans. While soil isolates of nematodes belonging to the family Rhabditidae are repelled by the aglycone, laboratory strains and natural isolates of Caenorhabditis sp. are attracted to the compound, mediated by receptors that are independent of Dop-1, leading to their death. The β-glucosides-positive (Bgl(+)) bacteria that are otherwise non-pathogenic can obtain additional nutrients from the dead predators, thereby switching their role from prey to predator. This study also offers an evolutionary explanation for the retention by bacteria of 'cryptic' or 'silent' genetic systems such as the bgl operon.
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Affiliation(s)
- Robert Sonowal
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560 012, India
| | - Krithi Nandimath
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560 012, India
| | | | - Sandhya P. Koushika
- National Centre for Biological Sciences, Bangalore 560065, India
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Vidyanand Nanjundiah
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560 012, India
| | - S. Mahadevan
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560 012, India
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Pseudomonas fluorescens NZI7 repels grazing by C. elegans, a natural predator. ISME JOURNAL 2013; 7:1126-38. [PMID: 23426012 DOI: 10.1038/ismej.2013.9] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The bacteriovorous nematode Caenorhabditis elegans has been used to investigate many aspects of animal biology, including interactions with pathogenic bacteria. However, studies examining C. elegans interactions with bacteria isolated from environments in which it is found naturally are relatively scarce. C. elegans is frequently associated with cultivation of the edible mushroom Agaricus bisporus, and has been reported to increase the severity of bacterial blotch of mushrooms, a disease caused by bacteria from the Pseudomonas fluorescens complex. We observed that pseudomonads isolated from mushroom farms showed differential resistance to nematode predation. Under nutrient poor conditions, in which most pseudomonads were consumed, the mushroom pathogenic isolate P. fluorescens NZI7 was able to repel C. elegans without causing nematode death. A draft genome sequence of NZI7 showed it to be related to the biocontrol strain P. protegens Pf-5. To identify the genetic basis of nematode repellence in NZI7, we developed a grid-based screen for mutants that lacked the ability to repel C. elegans. The mutants isolated in this screen included strains with insertions in the global regulator GacS and in a previously undescribed GacS-regulated gene cluster, 'EDB' ('edible'). Our results suggest that the product of the EDB cluster is a poorly diffusible or cell-associated factor that acts together with other features of NZI7 to provide a novel mechanism to deter nematode grazing. As nematodes interact with NZI7 colonies before being repelled, the EDB factor may enable NZI7 to come into contact with and be disseminated by C. elegans without being subject to intensive predation.
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Kravchenko VV, Kaufmann GF. Bacterial inhibition of inflammatory responses via TLR-independent mechanisms. Cell Microbiol 2013; 15:527-36. [DOI: 10.1111/cmi.12109] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 01/07/2013] [Accepted: 01/10/2013] [Indexed: 12/16/2022]
Affiliation(s)
- Vladimir V. Kravchenko
- Department of Immunology & Microbial Science; The Scripps Research Institute; 10550 North Torrey Pines Road; La Jolla; CA; 92037; USA
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Sarabhai S, Sharma P, Capalash N. Ellagic acid derivatives from Terminalia chebula Retz. downregulate the expression of quorum sensing genes to attenuate Pseudomonas aeruginosa PAO1 virulence. PLoS One 2013; 8:e53441. [PMID: 23320085 PMCID: PMC3539995 DOI: 10.1371/journal.pone.0053441] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 11/28/2012] [Indexed: 11/25/2022] Open
Abstract
Background Burgeoning antibiotic resistance in Pseudomonas aeruginosa has necessitated the development of anti pathogenic agents that can quench acylhomoserine lactone (AHL) mediated QS with least risk of resistance. This study explores the anti quorum sensing potential of T. chebula Retz. and identification of probable compounds(s) showing anti QS activity and the mechanism of attenuation of P. aeruginosa PAO1 virulence factors. Methods and Results Methanol extract of T. chebula Retz. fruit showed anti QS activity using Agrobacterium tumefaciens A136. Bioactive fraction (F7), obtained by fractionation of methanol extract using Sephadex LH20, showed significant reduction (p<0.001) in QS regulated production of extracellular virulence factors in P. aeruginosa PAO1. Biofilm formation and alginate were significantly (p<0.05) reduced with enhanced (20%) susceptibility to tobramycin. Real Time PCR of F7 treated P. aeruginosa showed down regulation of autoinducer synthase (lasI and rhlI) and their cognate receptor (lasR and rhlR) genes by 89, 90, 90 and 93%, respectively. Electrospray Ionization Mass Spectrometry also showed 90 and 64% reduction in the production of 3-oxo-C12HSL and C4HSL after treatment. Decrease in AHLs as one of the mechanisms of quorum quenching by F7 was supported by the reversal of inhibited swarming motility in F7-treated P. aeruginosa PAO1 on addition of C4HSL. F7 also showed antagonistic activity against 3-oxo-C12HSL-dependent QS in E. coli bioreporter. C. elegans fed on F7-treated P. aeruginosa showed enhanced survival with LT50 increasing from 24 to 72 h. LC-ESI-MS of F7 revealed the presence of ellagic acid derivatives responsible for anti QS activity in T. chebula extract. Conclusions This is the first report on anti QS activity of T. chebula fruit linked to EADs which down regulate the expression of lasIR and rhlIR genes with concomitant decrease in AHLs in P. aeruginosa PAO1 causing attenuation of its virulence factors and enhanced sensitivity of its biofilm towards tobramycin.
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Affiliation(s)
- Sajal Sarabhai
- Department of Microbiology, Panjab University, Chandigarh, India
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Osanai A, Hu DL, Nakane A. Caenorhabditis elegansavoids staphylococcal superantigenic toxins via 5-hydroxytryptamine-dependent pathway. Can J Microbiol 2012; 58:1268-77. [DOI: 10.1139/w2012-107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Avoidance behavior of Caenorhabditis elegans, a nematode, towards Staphylococcus aureus, a pathogenic bacterium, was studied. Caenorhabditis elegans avoided S. aureus cultures and also their culture supernatants, suggesting that secretory molecules are involved in the repellent activity. We demonstrated that toxic shock syndrome toxin 1 (TSST-1) and staphylococcal enterotoxin C (SEC), the superantigenic toxins produced by S. aureus, are responsible for the nematode avoidance. By using TSST-1 and SEC mutants, the results indicated that the repellent activity of these toxins is independent of their superantigenic activity. The TSST-1 and SEC were found to locate at chemosensory neurons that are responsible for the recognition of repellents and avoidance of pathogenic bacteria. When mutants of C. elegans deficient in Toll/interleukin-1 receptor (TIR-1) and 5-hydroxytryptamine (5-HT) biosynthesis were used, avoidance behavior was attenuated. In the 5-HT biosynthesis deficient mutant nematodes, the avoidance activity was recovered when exogenous 5-HT was added. tph-1 expression and 5-HT production were upregulated when the nematodes were treated with TSST-1 or SEC. These results suggest that C. elegans avoids S. aureus by recognizing secretory molecules including TSST-1 and SEC and this avoidance is dependent on TIR and production of 5-HT.
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Affiliation(s)
- Arihiro Osanai
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, 036-8562, Japan
| | - Dong-Liang Hu
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, 036-8562, Japan
| | - Akio Nakane
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, 036-8562, Japan
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Simonsen KT, Gallego SF, Færgeman NJ, Kallipolitis BH. Strength in numbers: "Omics" studies of C. elegans innate immunity. Virulence 2012; 3:477-84. [PMID: 23076279 PMCID: PMC3524146 DOI: 10.4161/viru.21906] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
For more than ten years the nematode Caenorhabditis elegans has proven to be a valuable model for studies of the host response to various bacterial and fungal pathogens. When exposed to a pathogenic organism, a clear response is elicited in the nematode, which is characterized by specific alterations on the transcriptional and translational levels. Early on, researchers took advantage of the possibility to conduct large-scale investigations of the C. elegans immune response. Multiple studies demonstrated that C. elegans does indeed mount a protective response against invading pathogens, thus rendering this small nematode a very useful and simple host model for the study of innate immunity and host-pathogen interactions. Here, we provide an overview of key aspects of innate immunity in C. elegans revealed by recent whole-genome transcriptomics and proteomics studies of the global response of C. elegans to various bacterial and fungal pathogens.
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Affiliation(s)
- Karina T Simonsen
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
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Padmanabhan V, Khan ZS, Solomon DE, Armstrong A, Rumbaugh KP, Vanapalli SA, Blawzdziewicz J. Locomotion of C. elegans: a piecewise-harmonic curvature representation of nematode behavior. PLoS One 2012; 7:e40121. [PMID: 22792224 PMCID: PMC3391229 DOI: 10.1371/journal.pone.0040121] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 06/01/2012] [Indexed: 11/18/2022] Open
Abstract
Caenorhabditis elegans, a free-living soil nematode, displays a rich variety of body shapes and trajectories during its undulatory locomotion in complex environments. Here we show that the individual body postures and entire trails of C. elegans have a simple analytical description in curvature representation. Our model is based on the assumption that the curvature wave is generated in the head segment of the worm body and propagates backwards. We have found that a simple harmonic function for the curvature can capture multiple worm shapes during the undulatory movement. The worm body trajectories can be well represented in terms of piecewise sinusoidal curvature with abrupt changes in amplitude, wavevector, and phase.
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Affiliation(s)
- Venkat Padmanabhan
- Venkat Padmanabhan Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas, United States of America.
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Sahu SN, Lewis J, Patel I, Bozdag S, Lee JH, LeClerc JE, Cinar HN. Genomic analysis of immune response against Vibrio cholerae hemolysin in Caenorhabditis elegans. PLoS One 2012; 7:e38200. [PMID: 22675448 PMCID: PMC3364981 DOI: 10.1371/journal.pone.0038200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 05/04/2012] [Indexed: 11/18/2022] Open
Abstract
Vibrio cholerae cytolysin (VCC) is among the accessory V. cholerae virulence factors that may contribute to disease pathogenesis in humans. VCC, encoded by hlyA gene, belongs to the most common class of bacterial toxins, known as pore-forming toxins (PFTs). V. cholerae infects and kills Caenorhabditis elegans via cholerae toxin independent manner. VCC is required for the lethality, growth retardation and intestinal cell vacuolation during the infection. However, little is known about the host gene expression responses against VCC. To address this question we performed a microarray study in C. elegans exposed to V. cholerae strains with intact and deleted hlyA genes. Many of the VCC regulated genes identified, including C-type lectins, Prion-like (glutamine [Q]/asparagine [N]-rich)-domain containing genes, genes regulated by insulin/IGF-1-mediated signaling (IIS) pathway, were previously reported as mediators of innate immune response against other bacteria in C. elegans. Protective function of the subset of the genes up-regulated by VCC was confirmed using RNAi. By means of a machine learning algorithm called FastMEDUSA, we identified several putative VCC induced immune regulatory transcriptional factors and transcription factor binding motifs. Our results suggest that VCC is a major virulence factor, which induces a wide variety of immune response- related genes during V. cholerae infection in C. elegans.
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Affiliation(s)
- Surasri N. Sahu
- Division of Virulence Assessment, Food and Drug Administration, Laurel, Maryland, United States of America
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee, United States of America
| | - Jada Lewis
- Division of Molecular Biology, Food and Drug Administration, Laurel, Maryland, United States of America
| | - Isha Patel
- Division of Molecular Biology, Food and Drug Administration, Laurel, Maryland, United States of America
| | - Serdar Bozdag
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jeong H. Lee
- Division of Virulence Assessment, Food and Drug Administration, Laurel, Maryland, United States of America
- Kyungpook National University (KNU), Daegu, South Korea
| | - Joseph E. LeClerc
- Division of Molecular Biology, Food and Drug Administration, Laurel, Maryland, United States of America
| | - Hediye Nese Cinar
- Division of Virulence Assessment, Food and Drug Administration, Laurel, Maryland, United States of America
- * E-mail:
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