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Haley JA, Chalasani SH. C. elegans foraging as a model for understanding the neuronal basis of decision-making. Cell Mol Life Sci 2024; 81:252. [PMID: 38849591 DOI: 10.1007/s00018-024-05223-1] [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: 12/14/2023] [Revised: 03/27/2024] [Accepted: 03/30/2024] [Indexed: 06/09/2024]
Abstract
Animals have evolved to seek, select, and exploit food sources in their environment. Collectively termed foraging, these ubiquitous behaviors are necessary for animal survival. As a foundation for understanding foraging, behavioral ecologists established early theoretical and mathematical frameworks which have been subsequently refined and supported by field and laboratory studies of foraging animals. These simple models sought to explain how animals decide which strategies to employ when locating food, what food items to consume, and when to explore the environment for new food sources. These foraging decisions involve integration of prior experience with multimodal sensory information about the animal's current environment and internal state. We suggest that the nematode Caenorhabditis elegans is well-suited for a high-resolution analysis of complex goal-oriented behaviors such as foraging. We focus our discussion on behavioral studies highlighting C. elegans foraging on bacteria and summarize what is known about the underlying neuronal and molecular pathways. Broadly, we suggest that this simple model system can provide a mechanistic understanding of decision-making and present additional avenues for advancing our understanding of complex behavioral processes.
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Affiliation(s)
- Jessica A Haley
- Neurosciences Graduate Program, University of California San Diego, La Jolla, CA, 92093, USA
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Sreekanth H Chalasani
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA.
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2
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Ding SS, Fox JL, Gordus A, Joshi A, Liao JC, Scholz M. Fantastic beasts and how to study them: rethinking experimental animal behavior. J Exp Biol 2024; 227:jeb247003. [PMID: 38372042 PMCID: PMC10911175 DOI: 10.1242/jeb.247003] [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] [Indexed: 02/20/2024]
Abstract
Humans have been trying to understand animal behavior at least since recorded history. Recent rapid development of new technologies has allowed us to make significant progress in understanding the physiological and molecular mechanisms underlying behavior, a key goal of neuroethology. However, there is a tradeoff when studying animal behavior and its underlying biological mechanisms: common behavior protocols in the laboratory are designed to be replicable and controlled, but they often fail to encompass the variability and breadth of natural behavior. This Commentary proposes a framework of 10 key questions that aim to guide researchers in incorporating a rich natural context into their experimental design or in choosing a new animal study system. The 10 questions cover overarching experimental considerations that can provide a template for interspecies comparisons, enable us to develop studies in new model organisms and unlock new experiments in our quest to understand behavior.
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Affiliation(s)
- Siyu Serena Ding
- Max Planck Institute of Animal Behavior, 78464 Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78464 Konstanz, Germany
| | - Jessica L. Fox
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Andrew Gordus
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Abhilasha Joshi
- Departments of Physiology and Psychiatry, University of California, San Francisco, CA 94158, USA
| | - James C. Liao
- Department of Biology, The Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
| | - Monika Scholz
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesar, 53175 Bonn, Germany
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3
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Sherman D, Harel D. Deciphering the underlying mechanisms of the pharyngeal pumping motions in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2024; 121:e2302660121. [PMID: 38315866 PMCID: PMC10873627 DOI: 10.1073/pnas.2302660121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 12/29/2023] [Indexed: 02/07/2024] Open
Abstract
The pharynx of the nematode Caenorhabditis elegans is a neuromuscular organ that exhibits typical pumping motions, which result in the intake of food particles from the environment. In-depth inspection reveals slightly different dynamics at the various pharyngeal areas, rather than synchronous pumping motions of the whole organ, which are important for its effective functioning. While the different pumping dynamics are well characterized, the underlying mechanisms that generate them are not known. In this study, the C. elegans pharynx was modeled in a bottom-up fashion, including all of the underlying biological processes that lead to, and including, its end function, food intake. The mathematical modeling of all processes allowed performing comprehensive, quantitative analyses of the system as a whole. Our analyses provided detailed explanations for the various pumping dynamics generated at the different pharyngeal areas; a fine-resolution description of muscle dynamics, both between and within different pharyngeal areas; a quantitative assessment of the values of many parameters of the system that are unavailable in the literature; and support for a functional role of the marginal cells, which are currently assumed to mainly have a structural role in the pharynx. In addition, our model predicted that in tiny organisms such as C. elegans, the generation of long-lasting action potentials must involve ions other than calcium. Our study exemplifies the power of mathematical models, which allow a more accurate, higher-resolution inspection of the studied system, and an easier and faster execution of in silico experiments than feasible in the lab.
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Affiliation(s)
- Dana Sherman
- Department of Computer Science and Applied Mathematics, Faculty of Mathematics and Computer Science, The Weizmann Institute of Science, Rehovot76100, Israel
| | - David Harel
- Department of Computer Science and Applied Mathematics, Faculty of Mathematics and Computer Science, The Weizmann Institute of Science, Rehovot76100, Israel
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4
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Ishita Y, Onodera A, Ekino T, Chihara T, Okumura M. Co-option of an Astacin Metalloprotease Is Associated with an Evolutionarily Novel Feeding Morphology in a Predatory Nematode. Mol Biol Evol 2023; 40:msad266. [PMID: 38105444 PMCID: PMC10753534 DOI: 10.1093/molbev/msad266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 10/14/2023] [Accepted: 11/16/2023] [Indexed: 12/19/2023] Open
Abstract
Animals consume a wide variety of food sources to adapt to different environments. However, the genetic mechanisms underlying the acquisition of evolutionarily novel feeding morphology remain largely unknown. While the nematode Caenorhabditis elegans feeds on bacteria, the satellite species Pristionchus pacificus exhibits predatory feeding behavior toward other nematodes, which is an evolutionarily novel feeding habit. Here, we found that the astacin metalloprotease Ppa-NAS-6 is required for the predatory killing by P. pacificus. Ppa-nas-6 mutants were defective in predation-associated characteristics, specifically the tooth morphogenesis and tooth movement during predation. Comparison of expression patterns and rescue experiments of nas-6 in P. pacificus and C. elegans suggested that alteration of the spatial expression patterns of NAS-6 may be vital for acquiring predation-related traits. Reporter analysis of the Ppa-nas-6 promoter in C. elegans revealed that the alteration in expression patterns was caused by evolutionary changes in cis- and trans-regulatory elements. This study suggests that the co-option of a metalloprotease is involved in an evolutionarily novel feeding morphology.
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Affiliation(s)
- Yuuki Ishita
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Ageha Onodera
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Taisuke Ekino
- School of Agriculture, Meiji University, Kawasaki 214-8571, Japan
| | - Takahiro Chihara
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
- Program of Basic Biology, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Misako Okumura
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
- Program of Basic Biology, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
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5
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Jordan DJ, Miska EA. Canalisation and plasticity on the developmental manifold of Caenorhabditis elegans. Mol Syst Biol 2023; 19:e11835. [PMID: 37850520 PMCID: PMC10632735 DOI: 10.15252/msb.202311835] [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: 06/21/2023] [Revised: 09/26/2023] [Accepted: 10/05/2023] [Indexed: 10/19/2023] Open
Abstract
How do the same mechanisms that faithfully regenerate complex developmental programmes in spite of environmental and genetic perturbations also allow responsiveness to environmental signals, adaptation and genetic evolution? Using the nematode Caenorhabditis elegans as a model, we explore the phenotypic space of growth and development in various genetic and environmental contexts. Our data are growth curves and developmental parameters obtained by automated microscopy. Using these, we show that among the traits that make up the developmental space, correlations within a particular context are predictive of correlations among different contexts. Furthermore, we find that the developmental variability of this animal can be captured on a relatively low-dimensional phenotypic manifold and that on this manifold, genetic and environmental contributions to plasticity can be deconvolved independently. Our perspective offers a new way of understanding the relationship between robustness and flexibility in complex systems, suggesting that projection and concentration of dimension can naturally align these forces as complementary rather than competing.
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Affiliation(s)
- David J Jordan
- Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - Eric A Miska
- Department of BiochemistryUniversity of CambridgeCambridgeUK
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6
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Madirolas G, Al-Asmar A, Gaouar L, Marie-Louise L, Garza-Enríquez A, Rodríguez-Rada V, Khona M, Dal Bello M, Ratzke C, Gore J, Pérez-Escudero A. Caenorhabditis elegans foraging patterns follow a simple rule of thumb. Commun Biol 2023; 6:841. [PMID: 37580527 PMCID: PMC10425387 DOI: 10.1038/s42003-023-05220-3] [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: 08/04/2022] [Accepted: 08/04/2023] [Indexed: 08/16/2023] Open
Abstract
Rules of thumb are behavioral algorithms that approximate optimal behavior while lowering cognitive and sensory costs. One way to reduce these costs is by simplifying the representation of the environment: While the theoretically optimal behavior may depend on many environmental variables, a rule of thumb may use a smaller set of variables that performs reasonably well. Experimental proof of this simplification requires an exhaustive mapping of all relevant combinations of several environmental parameters, which we performed for Caenorhabditis elegans foraging by covering systematically combinations of food density (across 4 orders of magnitude) and food type (across 12 bacterial strains). We found that worms' response is dominated by a single environmental variable: food density measured as number of bacteria per unit surface. They disregard other factors such as biomass content or bacterial strain. We also measured experimentally the impact on fitness of each type of food, determining that the rule is near-optimal and therefore constitutes a rule of thumb that leverages the most informative environmental variable. These results set the stage for further investigations into the underlying genetic and neural mechanisms governing this simplification process, and into its role in the evolution of decision-making strategies.
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Affiliation(s)
- Gabriel Madirolas
- Centre de Recherches sur la Cognition Animale (UMR5169), Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, 31062, France
| | - Alid Al-Asmar
- Centre de Recherches sur la Cognition Animale (UMR5169), Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, 31062, France
| | - Lydia Gaouar
- Centre de Recherches sur la Cognition Animale (UMR5169), Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, 31062, France
| | - Leslie Marie-Louise
- Centre de Recherches sur la Cognition Animale (UMR5169), Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, 31062, France
| | - Andrea Garza-Enríquez
- Centre de Recherches sur la Cognition Animale (UMR5169), Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, 31062, France
| | - Valentina Rodríguez-Rada
- Centre de Recherches sur la Cognition Animale (UMR5169), Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, 31062, France
| | - Mikail Khona
- Physics of Living Systems Group, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Martina Dal Bello
- Physics of Living Systems Group, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Christoph Ratzke
- Physics of Living Systems Group, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), Cluster of Excellence EXC 2124 "Controlling Microbes to Fight Infections" (CMFI), University of Tübingen, Calwerstrasse 7/1, 72076, Tübingen, Germany
| | - Jeff Gore
- Physics of Living Systems Group, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Alfonso Pérez-Escudero
- Centre de Recherches sur la Cognition Animale (UMR5169), Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, 31062, France.
- Physics of Living Systems Group, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
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7
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Engelfriet ML, Małecki JM, Forsberg AF, Falnes PØ, Ciosk R. Characterization of the biochemical activity and tumor-promoting role of the dual protein methyltransferase METL-13/METTL13 in Caenorhabditis elegans. PLoS One 2023; 18:e0287558. [PMID: 37347777 PMCID: PMC10286969 DOI: 10.1371/journal.pone.0287558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/07/2023] [Indexed: 06/24/2023] Open
Abstract
The methyltransferase-like protein 13 (METTL13) methylates the eukaryotic elongation factor 1 alpha (eEF1A) on two locations: the N-terminal amino group and lysine 55. The absence of this methylation leads to reduced protein synthesis and cell proliferation in human cancer cells. Previous studies showed that METTL13 is dispensable in non-transformed cells, making it potentially interesting for cancer therapy. However, METTL13 has not been examined yet in whole animals. Here, we used the nematode Caenorhabditis elegans as a simple model to assess the functions of METTL13. Using methyltransferase assays and mass spectrometry, we show that the C. elegans METTL13 (METL-13) methylates eEF1A (EEF-1A) in the same way as the human protein. Crucially, the cancer-promoting role of METL-13 is also conserved and depends on the methylation of EEF-1A, like in human cells. At the same time, METL-13 appears dispensable for animal growth, development, and stress responses. This makes C. elegans a convenient whole-animal model for studying METL13-dependent carcinogenesis without the complications of interfering with essential wild-type functions.
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Affiliation(s)
- Melanie L. Engelfriet
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Jędrzej M. Małecki
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Anna F. Forsberg
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Pål Ø. Falnes
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Rafal Ciosk
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
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8
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Levichev A, Faumont S, Berner RZ, Purcell Z, White AM, Chicas-Cruz K, Lockery SR. The conserved endocannabinoid anandamide modulates olfactory sensitivity to induce hedonic feeding in C. elegans. Curr Biol 2023; 33:1625-1639.e4. [PMID: 37084730 PMCID: PMC10175219 DOI: 10.1016/j.cub.2023.03.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 02/28/2023] [Accepted: 03/06/2023] [Indexed: 04/23/2023]
Abstract
The ability of cannabis to increase food consumption has been known for centuries. In addition to producing hyperphagia, cannabinoids can amplify existing preferences for calorically dense, palatable food sources, a phenomenon called hedonic amplification of feeding. These effects result from the action of plant-derived cannabinoids that mimic endogenous ligands called endocannabinoids. The high degree of conservation of cannabinoid signaling at the molecular level across the animal kingdom suggests hedonic feeding may also be widely conserved. Here, we show that exposure of Caenorhabditis elegans to anandamide, an endocannabinoid common to nematodes and mammals, shifts both appetitive and consummatory responses toward nutritionally superior food, an effect analogous to hedonic feeding. We find that anandamide's effect on feeding requires the C. elegans cannabinoid receptor NPR-19 but can also be mediated by the human CB1 cannabinoid receptor, indicating functional conservation between the nematode and mammalian endocannabinoid systems for the regulation of food preferences. Furthermore, anandamide has reciprocal effects on appetitive and consummatory responses to food, increasing and decreasing responses to inferior and superior foods, respectively. Anandamide's behavioral effects require the AWC chemosensory neurons, and anandamide renders these neurons more sensitive to superior foods and less sensitive to inferior foods, mirroring the reciprocal effects seen at the behavioral level. Our findings reveal a surprising degree of functional conservation in the effects of endocannabinoids on hedonic feeding across species and establish a new system to investigate the cellular and molecular basis of endocannabinoid system function in the regulation of food choice.
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Affiliation(s)
- Anastasia Levichev
- University of Oregon, Institute of Neuroscience, 1245 University of Oregon, Eugene, OR 97403, USA
| | - Serge Faumont
- University of Oregon, Institute of Neuroscience, 1245 University of Oregon, Eugene, OR 97403, USA
| | - Rachel Z Berner
- University of Oregon, Institute of Neuroscience, 1245 University of Oregon, Eugene, OR 97403, USA
| | - Zhifeng Purcell
- University of Oregon, Institute of Neuroscience, 1245 University of Oregon, Eugene, OR 97403, USA
| | - Amanda M White
- University of Oregon, Institute of Neuroscience, 1245 University of Oregon, Eugene, OR 97403, USA
| | - Kathy Chicas-Cruz
- University of Oregon, Institute of Neuroscience, 1245 University of Oregon, Eugene, OR 97403, USA
| | - Shawn R Lockery
- University of Oregon, Institute of Neuroscience, 1245 University of Oregon, Eugene, OR 97403, USA.
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9
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The Assembly of Bacteria Living in Natural Environments Shapes Neuronal Integrity and Behavioral Outputs in Caenorhabditis elegans. mBio 2023; 14:e0340222. [PMID: 36883821 PMCID: PMC10127743 DOI: 10.1128/mbio.03402-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023] Open
Abstract
Bacterivore nematodes are the most abundant animals in the biosphere, largely contributing to global biogeochemistry. Thus, the effects of environmental microbes on the nematodes' life-history traits are likely to contribute to the general health of the biosphere. Caenorhabditis elegans is an excellent model to study the behavioral and physiological outputs of microbial diets. However, the effects of complex natural bacterial assemblies have only recently been reported, as most studies have been carried out with monoxenic cultures of laboratory-reared bacteria. Here, we quantified the physiological, phenotypic, and behavioral traits of C. elegans feeding on two bacteria that were coisolated with wild nematodes from a soil sample. These bacteria were identified as a putative novel species of Stenotrophomonas named Stenotrophomonas sp. strain Iso1 and a strain of Bacillus pumilus designated Iso2. The distinctive behaviors and developmental patterns observed in animals fed with individual isolates changed when bacteria were mixed. We studied in more depth the degeneration rate of the touch circuit of C. elegans and show that B. pumilus alone is protective, while the mix with Stenotrophomonas sp. is degenerative. The analysis of the metabolite contents of each isolate and their combination identified NAD+ as being potentially neuroprotective. In vivo supplementation shows that NAD+ restores neuroprotection to the mixes and also to individual nonprotective bacteria. Our results highlight the distinctive physiological effects of bacteria resembling native diets in a multicomponent scenario rather than using single isolates on nematodes. IMPORTANCE Do behavioral choices depend on animals' microbiota? To answer this question, we studied how different bacterial assemblies impact the life-history traits of the bacterivore nematode C. elegans using isolated bacteria found in association with wild nematodes in Chilean soil. We identified the first isolate, Iso1, as a novel species of Stenotrophomonas and isolate Iso2 as Bacillus pumilus. We find that worm traits such as food choice, pharyngeal pumping, and neuroprotection, among others, are dependent on the biota composition. For example, the neurodegeneration of the touch circuit needed to sense and escape from predators in the wild decreases when nematodes are fed on B. pumilus, while its coculture with Stenotrophomonas sp. eliminates neuroprotection. Using metabolomics analysis, we identify metabolites such as NAD+, present in B. pumilus yet lost in the mix, as being neuroprotective and validated their protective effects using in vivo experiments.
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Bart S, Jager T, Short S, Robinson A, Sleep D, Pereira MG, Spurgeon DJ, Ashauer R. Modelling the effects of the pyrethroid insecticide cypermethrin on the life cycle of the soil dwelling annelid Enchytraeus crypticus, an original experimental design to calibrate a DEB-TKTD model. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 250:114499. [PMID: 36610295 DOI: 10.1016/j.ecoenv.2023.114499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 12/05/2022] [Accepted: 01/01/2023] [Indexed: 06/17/2023]
Abstract
The Dynamic Energy Budget theory (DEB) enables ecotoxicologists to model the effects of chemical stressors on organism life cycles through the coupling of toxicokinetic-toxicodynamic (TK-TD) models. While good progress has been made in the application of DEB-TKTD models for aquatic organisms, applications for soil fauna are scarce, due to the lack of dedicated experimental designs suitable for collecting the required time series effect data. Enchytraeids (Annelida: Clitellata) are model organisms in soil ecology and ecotoxicology. They are recognised as indicators of biological activity in soil, and chemical stress in terrestrial ecosystems. Despite this, the application of DEB-TKTD models to investigate the impact of chemicals has not yet been tested on this family. Here we assessed the impact of the pyrethroid insecticide cypermethrin on the life cycle of Enchytraeus crypticus. We developed an original experimental design to collect the data required for the calibration of a DEB-TKTD model for this species. E. crypticus presented a slow initial growth phase that has been successfully simulated with the addition of a size-dependent food limitation for juveniles in the DEB model. The DEB-TKTD model simulations successfully agreed with the data for all endpoints and treatments over time. The highlighted physiological mode of action (pMoA) for cypermethrin was an increase of the growth energy cost. The threshold for effects on survival was estimated at 73.14 mg kg- 1, and the threshold for effects on energy budget (i.e., sublethal effects) at 19.21 mg kg- 1. This study demonstrates that DEB-TKTD models can be successfully applied to E. crypticus as a representative soil species, and may improve the ecological risk assessment for terrestrial ecosystems, and our mechanistic understanding of chemical effects on non-target species.
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Affiliation(s)
- Sylvain Bart
- Department of Environment and Geography, University of York, York YO10 5NG, UK; UK Centre for Ecology and Hydrology, Wallingford OX10 8BB, UK; MO-ECO2 (Modelling and Data Analyses for Ecology and Ecotoxicology), Paris, France.
| | | | - Stephen Short
- UK Centre for Ecology and Hydrology, Wallingford OX10 8BB, UK
| | - Alex Robinson
- UK Centre for Ecology and Hydrology, Wallingford OX10 8BB, UK
| | - Darren Sleep
- UK Centre for Ecology & Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP, UK
| | - M Glória Pereira
- UK Centre for Ecology & Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP, UK
| | | | - Roman Ashauer
- Department of Environment and Geography, University of York, York YO10 5NG, UK; Syngenta Crop Protection AG, Basel 4058, Switzerland
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11
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Fatima H, Ahmad I. Effect of age on the structure and activity of the pharynx of the free-living nematode Metarhabditis andrassyana (Rhabditidae). ZOOMORPHOLOGY 2022. [DOI: 10.1007/s00435-022-00581-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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12
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Wang Y, Guo K, Wang Q, Zhong G, Zhang W, Jiang Y, Mao X, Li X, Huang Z. Caenorhabditis elegans as an emerging model in food and nutrition research: importance of standardizing base diet. Crit Rev Food Sci Nutr 2022; 64:3167-3185. [PMID: 36200941 DOI: 10.1080/10408398.2022.2130875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
As a model organism that has helped revolutionize life sciences, Caenorhabditis elegans has been increasingly used in nutrition research. Here we explore the tradeoffs between pros and cons of its use as a dietary model based primarily on literature review from the past decade. We first provide an overview of its experimental strengths as an animal model, focusing on lifespan and healthspan, behavioral and physiological phenotypes, and conservation of key nutritional pathways. We then summarize recent advances of its use in nutritional studies, e.g. food preference and feeding behavior, sugar status and metabolic reprogramming, lifetime and transgenerational nutrition tracking, and diet-microbiota-host interactions, highlighting cutting-edge technologies originated from or developed in C. elegans. We further review current challenges of using C. elegans as a nutritional model, followed by in-depth discussions on potential solutions. In particular, growth scales and throughputs, food uptake mode, and axenic culture of C. elegans are appraised in the context of food research. We also provide perspectives for future development of chemically defined nematode food ("NemaFood") for C. elegans, which is now widely accepted as a versatile and affordable in vivo model and has begun to show transformative potential to pioneer nutrition science.
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Affiliation(s)
- Yuqing Wang
- Institute for Food Nutrition and Human Health, School of Food Science and Engineering, South China University of Technology, Guangzhou, China
- Guangdong Province Key Laboratory for Biocosmetics, Guangzhou, China
| | - Kaixin Guo
- Institute for Food Nutrition and Human Health, School of Food Science and Engineering, South China University of Technology, Guangzhou, China
- The First Affiliated Hospital of Shenzhen University, Shenzhen, China
| | - Qiangqiang Wang
- Institute for Food Nutrition and Human Health, School of Food Science and Engineering, South China University of Technology, Guangzhou, China
- Guangdong Province Key Laboratory for Biocosmetics, Guangzhou, China
| | - Guohuan Zhong
- Institute for Food Nutrition and Human Health, School of Food Science and Engineering, South China University of Technology, Guangzhou, China
- Center for Bioresources and Drug Discovery, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, China
| | - Wenjun Zhang
- Center for Bioresources and Drug Discovery, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, China
| | - Yiyi Jiang
- Guangdong Province Key Laboratory for Biocosmetics, Guangzhou, China
- Perfect Life & Health Institute, Zhongshan, Guangdong, China
| | - Xinliang Mao
- Guangdong Province Key Laboratory for Biocosmetics, Guangzhou, China
- Perfect Life & Health Institute, Zhongshan, Guangdong, China
| | - Xiaomin Li
- Guangdong Province Key Laboratory for Biocosmetics, Guangzhou, China
- Perfect Life & Health Institute, Zhongshan, Guangdong, China
| | - Zebo Huang
- Institute for Food Nutrition and Human Health, School of Food Science and Engineering, South China University of Technology, Guangzhou, China
- Guangdong Province Key Laboratory for Biocosmetics, Guangzhou, China
- Center for Bioresources and Drug Discovery, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, China
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Suzuki Y, Kikuchi K, Numayama-Tsuruta K, Ishikawa T. Reciprocating intestinal flows enhance glucose uptake in C. elegans. Sci Rep 2022; 12:15310. [PMID: 36130988 PMCID: PMC9492717 DOI: 10.1038/s41598-022-18968-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 08/23/2022] [Indexed: 11/09/2022] Open
Abstract
Despite its physiological and pathological importance, the mechanical relationship between glucose uptake in the intestine and intestinal flows is unclear. In the intestine of the nematode Caenorhabditis elegans, the defecation motor program (DMP) causes reciprocating intestinal flows. Although the DMP is frequently activated in the intestines, its physiological function is unknown. We evaluated the mechanical signature of enhanced glucose uptake by the DMP in worms. Glucose uptake tended to increase with increasing flow velocity during the DMP because of mechanical mixing and transport. However, the increase in input energy required for the DMP was low compared with the calorie intake. The findings suggest that animals with gastrointestinal motility exploit the reciprocating intestinal flows caused by peristalsis to promote nutrient absorption by intestinal cells.
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Affiliation(s)
- Yuki Suzuki
- Graduate School of Engineering, Department of Finemechanics, Tohoku University, 6-6-01 Aramaki, Aoba, Sendai, Miyagi, 980-8579, Japan
| | - Kenji Kikuchi
- Graduate School of Engineering, Department of Finemechanics, Tohoku University, 6-6-01 Aramaki, Aoba, Sendai, Miyagi, 980-8579, Japan. .,Graduate School of Biomedical Engineering, Tohoku University, 6-6-01 Aramaki, Aoba, Sendai, Miyagi, 980-8579, Japan.
| | - Keiko Numayama-Tsuruta
- Graduate School of Biomedical Engineering, Tohoku University, 6-6-01 Aramaki, Aoba, Sendai, Miyagi, 980-8579, Japan
| | - Takuji Ishikawa
- Graduate School of Engineering, Department of Finemechanics, Tohoku University, 6-6-01 Aramaki, Aoba, Sendai, Miyagi, 980-8579, Japan.,Graduate School of Biomedical Engineering, Tohoku University, 6-6-01 Aramaki, Aoba, Sendai, Miyagi, 980-8579, Japan
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14
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Bonnard E, Liu J, Zjacic N, Alvarez L, Scholz M. Automatically tracking feeding behavior in populations of foraging C. elegans. eLife 2022; 11:e77252. [PMID: 36083280 PMCID: PMC9462848 DOI: 10.7554/elife.77252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
Caenorhabditis elegans feeds on bacteria and other small microorganisms which it ingests using its pharynx, a neuromuscular pump. Currently, measuring feeding behavior requires tracking a single animal, indirectly estimating food intake from population-level metrics, or using restrained animals. To enable large throughput feeding measurements of unrestrained, crawling worms on agarose plates at a single worm resolution, we developed an imaging protocol and a complementary image analysis tool called PharaGlow. We image up to 50 unrestrained crawling worms simultaneously and extract locomotion and feeding behaviors. We demonstrate the tool's robustness and high-throughput capabilities by measuring feeding in different use-case scenarios, such as through development, with genetic and chemical perturbations that result in faster and slower pumping, and in the presence or absence of food. Finally, we demonstrate that our tool is capable of long-term imaging by showing behavioral dynamics of mating animals and worms with different genetic backgrounds. The low-resolution fluorescence microscopes required are readily available in C. elegans laboratories, and in combination with our python-based analysis workflow makes this methodology easily accessible. PharaGlow therefore enables the observation and analysis of the temporal dynamics of feeding and locomotory behaviors with high-throughput and precision in a user-friendly system.
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Affiliation(s)
- Elsa Bonnard
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
| | - Jun Liu
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
| | - Nicolina Zjacic
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
- Institute of Medical Genetics, University of ZurichZurichSwitzerland
| | - Luis Alvarez
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
| | - Monika Scholz
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
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15
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Mallick S, Mishra N, Barik BK, Negi VD. Salmonella Typhimurium fepB negatively regulates C. elegans behavioral plasticity. J Infect 2022; 84:518-530. [PMID: 34990707 DOI: 10.1016/j.jinf.2021.12.043] [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: 09/04/2021] [Revised: 12/27/2021] [Accepted: 12/29/2021] [Indexed: 10/19/2022]
Abstract
OBJECTIVES Dauer is an alternative developmental stage of Caenorhabditis elegans (C. elegans) that gives survival benefits under unfavorable environmental conditions. Our study aims to decipher C. elegans dauer larvae development upon Salmonella Typhimurium infection and how the bacterial gene regulating the worm's behavioural plasticity for better survival. METHODS Age-synchronized L4 C. elegans worms were infected with Salmonella Typhimurium 14028s (WT-STM) strain and mutant strains to check the dauer larvae development using 1% SDS. Besides, bacterial load in animals' gut, pharyngeal pumping rate and viability were checked. Worm's immune genes (e.g., ilys-3, lys-7, pmk-1, abf-2, clec-60) and dauer regulatory genes (e.g., daf-7, daf-11, daf-12, daf-16, daf-3) were checked by performing qRT-PCR under infection conditions. RESULTS We found that deletion of the fepB gene in S. Typhimurium strain became less pathogenic with reduced flagellar motility and biofilm-forming ability. Besides, there was decreased bacterial burden in the worm's gut with no damage to their pharynx. The fepB mutant strain was also able to enhance the immune responses for better survival of worms. Infection with mutant strain could activate dauer signaling via the TGF-β pathway leading to a significant increase in dauer formation than WT-STM infection. CONCLUSION Our study indicated that the bacteria act as a food source for the growth of C. elegans and development and can act as a signal that might be playing an essential role in regulating the host physiology for their survival. Such a study can help us in understanding the complex host-pathogen interaction benefiting pathogen in host dissemination.
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Affiliation(s)
- Swarupa Mallick
- Laboratory of Infection Immunology, Department of Life Science, National Institute of Technology, Rourkela 769008, Odisha, India.
| | - Neha Mishra
- Laboratory of Infection Immunology, Department of Life Science, National Institute of Technology, Rourkela 769008, Odisha, India.
| | - Bedanta Kumar Barik
- Laboratory of Infection Immunology, Department of Life Science, National Institute of Technology, Rourkela 769008, Odisha, India.
| | - Vidya Devi Negi
- Laboratory of Infection Immunology, Department of Life Science, National Institute of Technology, Rourkela 769008, Odisha, India.
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16
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Ohno H, Bao Z. Small RNAs couple embryonic developmental programs to gut microbes. SCIENCE ADVANCES 2022; 8:eabl7663. [PMID: 35319987 PMCID: PMC8942359 DOI: 10.1126/sciadv.abl7663] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
Embryogenesis has long been known for its robustness to environmental factors. Although developmental tuning of embryogenesis to the environment experienced by the parent may be beneficial, little is understood on whether and how developmental patterns proactively change. Here, we show that Caenorhabditis elegans undergoes alternative embryogenesis in response to maternal gut microbes. Harmful microbes result in altered endodermal cell divisions; morphological changes, including left-right asymmetric development; double association between intestinal and primordial germ cells; and partial rescue of fecundity. The miR-35 microRNA family, which is controlled by systemic endogenous RNA interference and targets the β-transducin repeat-containing protein/cell division cycle 25 (CDC25) pathway, transmits intergenerational information to regulate cell divisions and reproduction. Our findings challenge the widespread assumption that C. elegans has an invariant cell lineage that consists of a fixed cell number and provide insights into how organisms optimize embryogenesis to adapt to environmental changes through epigenetic control.
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17
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Abstract
An enduring mystery of development is how its timing is controlled, particularly for development after birth, where timing is highly flexible and depends on environmental conditions, such as food availability and diet. We followed timing of cell- and organism-level events in individual Caenorhabditis elegans larvae developing from hatching to adulthood, uncovering widespread variations in event timing, both between isogenic individuals in the same environment and when changing conditions and genotypes. However, in almost all cases, we found that events occurred at the same time, when time was rescaled by the duration of development measured in each individual. This observation of “temporal scaling” poses strong constraints on models to explain timing of larval development. It is essential that correct temporal order of cellular events is maintained during animal development. During postembryonic development, the rate of development depends on external conditions, such as food availability, diet, and temperature. How timing of cellular events is impacted when the rate of development is changed at the organism level is not known. We used a unique time-lapse microscopy approach to simultaneously measure timing of oscillatory gene expression, hypodermal stem cell divisions, and cuticle shedding in individual Caenorhabditis elegans larvae, as they developed from hatching to adulthood. This revealed strong variability in timing between isogenic individuals under the same conditions. However, this variability obeyed “temporal scaling,” meaning that events occurred at the same time when measured relative to the total duration of development in each individual. We also observed pervasive changes in timing when temperature, diet, or genotype were varied, but with larval development divided in “epochs” that differed in how event timing was impacted. Yet, these variations in timing were still explained by temporal scaling when time was rescaled by the duration of the respective epochs in each individual. Surprisingly, timing obeyed temporal scaling even in mutants lacking lin-42/Period, presumed a core regulator of timing of larval development, that exhibited strongly delayed, heterogeneous timing. However, shifting conditions middevelopment perturbed temporal scaling and changed event order in a highly condition-specific manner, indicating that a complex machinery is responsible for temporal scaling under constant conditions.
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18
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Xie K, Liu Y, Li X, Zhang H, Zhang S, Mak HY, Liu P. Dietary S. maltophilia induces supersized lipid droplets by enhancing lipogenesis and ER-LD contacts in C. elegans. Gut Microbes 2022; 14:2013762. [PMID: 35112996 PMCID: PMC8816401 DOI: 10.1080/19490976.2021.2013762] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Dietary and symbiotic bacteria can exert powerful influence on metazoan lipid metabolism. Recent studies have emerged that microbiota have a role in animal obesity and related health disorders, but the mechanisms by which bacteria influence lipid storage in their host are unknown. To reduce the complexity of the relationship between gut microbiota and the host, Caenorhabditis elegans (C. elegans) has been chosen as a model organism to study interspecies interaction. Here, we demonstrate that feeding C. elegans with an opportunistic pathogenic bacterium Stenotrophomonas maltophilia (S. maltophilia) retards growth and promotes excessive neutral lipid storage. Gene expression analysis reveals that dietary S. maltophilia induces a lipogenic transcriptional response that includes the SREBP ortholog SBP-1, and fatty acid desaturases FAT-6 and FAT-7. Live imaging and ultrastructural analysis suggest that excess neutral lipid is stored in greatly expanded lipid droplets (LDs), as a result of enhanced endoplasmic reticulum (ER)-LD interaction. We also report that loss of function mutations in dpy-9 in C. elegans confers resistance to S. maltophilia. Dietary S. maltophilia induces supersized LDs by enhancing lipogenesis and ER-LD contacts in C. elegans. This work delineates a new model for understanding microbial regulation of metazoan physiology.
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Affiliation(s)
- Kang Xie
- National Laboratory of Biomacromolecules, Cas Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,University of Chinese Academy of Sciences, Beijing, China
| | - Yangli Liu
- National Laboratory of Biomacromolecules, Cas Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,University of Chinese Academy of Sciences, Beijing, China
| | - Xixia Li
- National Laboratory of Biomacromolecules, Cas Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Hong Zhang
- National Laboratory of Biomacromolecules, Cas Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,University of Chinese Academy of Sciences, Beijing, China
| | - Shuyan Zhang
- National Laboratory of Biomacromolecules, Cas Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Ho Yi Mak
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Pingsheng Liu
- National Laboratory of Biomacromolecules, Cas Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China,University of Chinese Academy of Sciences, Beijing, China,CONTACT Pingsheng Liu National Laboratory of Biomacromolecules, Cas Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing100101, China
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19
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Izquierdo PG, Calahorro F, Thisainathan T, Atkins JH, Haszczyn J, Lewis CJ, Tattersall JEH, Green AC, Holden-Dye L, O'Connor V. Cholinergic signaling at the body wall neuromuscular junction distally inhibits feeding behavior in Caenorhabditis elegans. J Biol Chem 2021; 298:101466. [PMID: 34864060 PMCID: PMC8801469 DOI: 10.1016/j.jbc.2021.101466] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 11/13/2021] [Accepted: 11/30/2021] [Indexed: 12/27/2022] Open
Abstract
Complex biological functions within organisms are frequently orchestrated by systemic communication between tissues. In the model organism Caenorhabditis elegans, the pharyngeal and body wall neuromuscular junctions are two discrete structures that control feeding and locomotion, respectively. Separate, the well-defined neuromuscular circuits control these distinct tissues. Nonetheless, the emergent behaviors, feeding and locomotion, are coordinated to guarantee the efficiency of food intake. Here, we show that pharmacological hyperactivation of cholinergic transmission at the body wall muscle reduces the rate of pumping behavior. This was evidenced by a systematic screening of the effect of the cholinesterase inhibitor aldicarb on the rate of pharyngeal pumping on food in mutant worms. The screening revealed that the key determinants of the inhibitory effect of aldicarb on pharyngeal pumping are located at the body wall neuromuscular junction. In fact, the selective stimulation of the body wall muscle receptors with the agonist levamisole inhibited pumping in a lev-1-dependent fashion. Interestingly, this response was independent of unc-38, an alpha subunit of the nicotinic receptor classically expressed with lev-1 at the body wall muscle. This implies an uncharacterized lev-1-containing receptor underpins this effect. Overall, our results reveal that body wall cholinergic transmission not only controls locomotion but simultaneously inhibits feeding behavior.
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Affiliation(s)
- Patricia G Izquierdo
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom.
| | - Fernando Calahorro
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Thibana Thisainathan
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - James H Atkins
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Johanna Haszczyn
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Christian J Lewis
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - John E H Tattersall
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - A Christopher Green
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Lindy Holden-Dye
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Vincent O'Connor
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
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20
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Schiffer JA, Stumbur SV, Seyedolmohadesin M, Xu Y, Serkin WT, McGowan NG, Banjo O, Torkashvand M, Lin A, Hosea CN, Assié A, Samuel BS, O’Donnell MP, Venkatachalam V, Apfeld J. Modulation of sensory perception by hydrogen peroxide enables Caenorhabditis elegans to find a niche that provides both food and protection from hydrogen peroxide. PLoS Pathog 2021; 17:e1010112. [PMID: 34941962 PMCID: PMC8699984 DOI: 10.1371/journal.ppat.1010112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 11/14/2021] [Indexed: 02/07/2023] Open
Abstract
Hydrogen peroxide (H2O2) is the most common chemical threat that organisms face. Here, we show that H2O2 alters the bacterial food preference of Caenorhabditis elegans, enabling the nematodes to find a safe environment with food. H2O2 induces the nematodes to leave food patches of laboratory and microbiome bacteria when those bacterial communities have insufficient H2O2-degrading capacity. The nematode's behavior is directed by H2O2-sensing neurons that promote escape from H2O2 and by bacteria-sensing neurons that promote attraction to bacteria. However, the input for H2O2-sensing neurons is removed by bacterial H2O2-degrading enzymes and the bacteria-sensing neurons' perception of bacteria is prevented by H2O2. The resulting cross-attenuation provides a general mechanism that ensures the nematode's behavior is faithful to the lethal threat of hydrogen peroxide, increasing the nematode's chances of finding a niche that provides both food and protection from hydrogen peroxide.
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Affiliation(s)
- Jodie A. Schiffer
- Biology Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Stephanie V. Stumbur
- Biology Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Maedeh Seyedolmohadesin
- Physics Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Yuyan Xu
- Biology Department, Northeastern University, Boston, Massachusetts, United States of America
| | - William T. Serkin
- Biology Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Natalie G. McGowan
- Biology Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Oluwatosin Banjo
- Biology Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Mahdi Torkashvand
- Physics Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Albert Lin
- Department of Physics, Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Ciara N. Hosea
- Alkek Center for Metagenomics and Microbiome Research and Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Adrien Assié
- Alkek Center for Metagenomics and Microbiome Research and Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Buck S. Samuel
- Alkek Center for Metagenomics and Microbiome Research and Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Michael P. O’Donnell
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Vivek Venkatachalam
- Physics Department, Northeastern University, Boston, Massachusetts, United States of America
| | - Javier Apfeld
- Biology Department, Northeastern University, Boston, Massachusetts, United States of America
- Bioengineering Department, Northeastern University, Boston, Massachusetts, United States of America
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21
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Bayer EA, Liberatore KM, Schneider JR, Schlesinger E, He Z, Birnbaum S, Wightman B. Insulin signaling and osmotic stress response regulate arousal and developmental progression of C. elegans at hatching. Genetics 2021; 220:6426082. [PMID: 34788806 DOI: 10.1093/genetics/iyab202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/03/2021] [Indexed: 12/29/2022] Open
Abstract
The progression of animal development from embryonic to juvenile life depends on the coordination of organism-wide responses with environmental conditions. We found that two transcription factors that function in interneuron differentiation in Caenorhabditis elegans, fax-1 and unc-42, are required for arousal and progression from embryogenesis to larval life by potentiating insulin signaling. The combination of mutations in either transcription factor and a mutation in daf-2 insulin receptor results in a novel peri-hatching arrest phenotype; embryos are fully-developed but inactive, often remaining trapped within the eggshell, and fail to initiate pharyngeal pumping. This pathway is opposed by an osmotic sensory response pathway that promotes developmental arrest and a sleep state at the end of embryogenesis in response to elevated salt concentration. The quiescent state induced by loss of insulin signaling or by osmotic stress can be reversed by mutations in genes that are required for sleep. Therefore, countervailing signals regulate late embryonic arousal and developmental progression to larval life, mechanistically linking the two responses. Our findings demonstrate a role for insulin signaling in an arousal circuit, consistent with evidence that insulin-related regulation may function in control of sleep states in many animals. The opposing quiescent arrest state may serve as an adaptive response to the osmotic threat from high salinity environments.
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Affiliation(s)
- Emily A Bayer
- Biology Department, Muhlenberg College, Allentown, PA 18104, USA
| | | | | | - Evan Schlesinger
- Biology Department, Muhlenberg College, Allentown, PA 18104, USA
| | - Zhengying He
- Biology Department, Muhlenberg College, Allentown, PA 18104, USA
| | - Susanna Birnbaum
- Biology Department, Muhlenberg College, Allentown, PA 18104, USA
| | - Bruce Wightman
- Biology Department, Muhlenberg College, Allentown, PA 18104, USA
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22
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Li Y, Ren L, Fu H, Yang B, Tian J, Li Q, Liu Z, Liu S. Crosstalk between dopamine and insulin signaling in growth control of the oyster. Gen Comp Endocrinol 2021; 313:113895. [PMID: 34480943 DOI: 10.1016/j.ygcen.2021.113895] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 07/20/2021] [Accepted: 08/29/2021] [Indexed: 12/26/2022]
Abstract
Neuroendocrine hormones such as dopamine and insulin/insulin-like peptides play indispensable roles in growth regulation of animals, while the interplay between dopamine and insulin signaling pathways remains largely unknown in invertebrates. In the present study, we showed that tyrosine hydroxylase (TH), the rate-limiting enzyme of dopamine synthesis, was highly expressed in all tissues of the fast-growing oysters, and gradually increased with the development, which indicated the potential role of dopamine in growth regulation. Incubated with dopamine hydrochloride and insulin-like peptide recombinant proteins in vitro induced the expression of TH, suggesting a mutual regulatory relationship between insulin and dopamine signaling. Fasting and re-feeding experiments confirmed the role of TH in food intake regulation, also provide a clue about the potential regulatory relationship between the FoxO and TH. Further luciferase assay experiment confirmed that FoxO was involved in transcriptional regulation of TH gene through binding to its specific promoter region. This work provided insights into the crosstalk between dopamine and insulin signaling in growth control of mollusks.
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Affiliation(s)
- Yongjing Li
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, and College of Fisheries, Ocean University of China, Qingdao 266003, China
| | - Liting Ren
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, and College of Fisheries, Ocean University of China, Qingdao 266003, China
| | - Huiru Fu
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, and College of Fisheries, Ocean University of China, Qingdao 266003, China
| | - Ben Yang
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, and College of Fisheries, Ocean University of China, Qingdao 266003, China
| | - Jing Tian
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, and College of Fisheries, Ocean University of China, Qingdao 266003, China
| | - Qi Li
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, and College of Fisheries, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Zhanjiang Liu
- Department of Biology, College of Art and Sciences, Syracuse University, Syracuse, NY 13244, USA
| | - Shikai Liu
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, and College of Fisheries, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
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Novel Nematode-Killing Protein-1 (Nkp-1) from a Marine Epiphytic Bacterium Pseudoalteromonas tunicata. Biomedicines 2021; 9:biomedicines9111586. [PMID: 34829814 PMCID: PMC8615270 DOI: 10.3390/biomedicines9111586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/22/2021] [Accepted: 10/22/2021] [Indexed: 12/12/2022] Open
Abstract
Drug resistance among parasitic nematodes has resulted in an urgent need for the development of new therapies. However, the high re-discovery rate of anti-nematode compounds from terrestrial environments necessitates a new repository for future drug research. Marine epiphytes are hypothesised to produce nematicidal compounds as a defence against bacterivorous predators, thus representing a promising yet underexplored source for anti-nematode drug discovery. The marine epiphytic bacterium Pseudoalteromonas tunicata is known to produce several bioactive compounds. Screening heterologously expressed genomic libraries of P. tunicata against the nematode Caenorhabditis elegans, identified as an E. coli clone (HG8), shows fast-killing activity. Here we show that clone HG8 produces a novel nematode-killing protein-1 (Nkp-1) harbouring a predicted carbohydrate-binding domain with weak homology to known bacterial pore-forming toxins. We found bacteria expressing Nkp-1 were able to colonise the C. elegans intestine, with exposure to both live bacteria and protein extracts resulting in physical damage and necrosis, leading to nematode death within 24 h of exposure. Furthermore, this study revealed C. elegans dar (deformed anal region) and internal hatching may act as a nematode defence strategy against Nkp-1 toxicity. The characterisation of this novel protein and putative mode of action not only contributes to the development of novel anti-nematode applications in the future but reaffirms the potential of marine epiphytic bacteria as a new source of novel biomolecules.
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Cahoon CK, Libuda DE. Conditional immobilization for live imaging Caenorhabditis elegans using auxin-dependent protein depletion. G3-GENES GENOMES GENETICS 2021; 11:6362942. [PMID: 34534266 PMCID: PMC8527506 DOI: 10.1093/g3journal/jkab310] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 08/19/2021] [Indexed: 11/12/2022]
Abstract
The visualization of biological processes using fluorescent proteins and dyes in living organisms has enabled numerous scientific discoveries. The nematode Caenorhabditis elegans is a widely used model organism for live imaging studies since the transparent nature of the worm enables imaging of nearly all tissues within a whole, intact animal. While current techniques are optimized to enable the immobilization of hermaphrodite worms for live imaging, many of these approaches fail to successfully restrain the smaller male worms. To enable live imaging of worms of both sexes, we developed a new genetic, conditional immobilization tool that uses the auxin-inducible degron (AID) system to immobilize both adult and larval hermaphrodite and male worms for live imaging. Based on chromosome location, mutant phenotype, and predicted germline consequence, we identified and AID-tagged three candidate genes (unc-18, unc-104, and unc-52). Strains with these AID-tagged genes were placed on auxin and tested for mobility and germline defects. Among the candidate genes, auxin-mediated depletion of UNC-18 caused significant immobilization of both hermaphrodite and male worms that was also partially reversible upon removal from auxin. Notably, we found that male worms require a higher concentration of auxin for a similar amount of immobilization as hermaphrodites, thereby suggesting a potential sex-specific difference in auxin absorption and/or processing. In both males and hermaphrodites, depletion of UNC-18 did not largely alter fertility, germline progression, nor meiotic recombination. Finally, we demonstrate that this new genetic tool can successfully immobilize both sexes enabling live imaging studies of sexually dimorphic features in C. elegans.
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Affiliation(s)
- Cori K Cahoon
- Department of Biology, Institute of Molecular Biology, University of Oregon, Eugene, OR 97403-1229, USA
| | - Diana E Libuda
- Department of Biology, Institute of Molecular Biology, University of Oregon, Eugene, OR 97403-1229, USA
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Hendler-Neumark A, Wulf V, Bisker G. In vivo imaging of fluorescent single-walled carbon nanotubes within C. elegans nematodes in the near-infrared window. Mater Today Bio 2021; 12:100175. [PMID: 34927042 PMCID: PMC8649898 DOI: 10.1016/j.mtbio.2021.100175] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/14/2021] [Accepted: 11/29/2021] [Indexed: 01/02/2023] Open
Abstract
Caenorhabditis elegans (C. elegans) nematodes serve as a model organism for eukaryotes, especially due to their genetic similarity. Although they have many advantages like their small size and transparency, their autofluorescence in the entire visible wavelength range poses a challenge for imaging and tracking fluorescent proteins or dyes using standard fluorescence microscopy. Herein, near-infrared (NIR) fluorescent single-walled carbon nanotubes (SWCNTs) are utilized for in vivo imaging within the gastrointestinal track of C. elegans. The SWCNTs are biocompatible, and do not affect the worms' viability nor their reproduction ability. The worms do not show any autofluorescence in the NIR range, thus enabling the spectral separation between the SWCNT NIR fluorescence and the strong autofluorescence of the worm gut granules. The worms are fed with ssDNA-SWCNT which are visualized mainly in the intestine lumen. The NIR fluorescence is used in vivo to track the contraction and relaxation in the area of the pharyngeal valve at the anterior of the terminal bulb. These biocompatible, non-photobleaching, NIR fluorescent nanoparticles can advance in vivo imaging and tracking within C. elegans and other small model organisms by overcoming the signal-to-noise challenge stemming from the wide-range visible autofluorescence.
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Affiliation(s)
- Adi Hendler-Neumark
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Verena Wulf
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Gili Bisker
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, 6997801, Israel
- Center for Physics and Chemistry of Living Systems, Tel-Aviv University, Tel Aviv, 6997801, Israel
- Center for Nanoscience and Nanotechnology, Tel-Aviv University, Tel Aviv, 6997801, Israel
- Center for Light Matter Interaction, Tel-Aviv University, Tel Aviv, 6997801, Israel
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Hendricks M. C. elegans does a spit take. eLife 2021; 10:71813. [PMID: 34342265 PMCID: PMC8331175 DOI: 10.7554/elife.71813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 07/30/2021] [Indexed: 11/13/2022] Open
Abstract
Eating can turn into spitting because individual parts of a muscle cell are able to contract in different ways.
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Avery L, Ingalls B, Dumur C, Artyukhin A. A Keller-Segel model for C elegans L1 aggregation. PLoS Comput Biol 2021; 17:e1009231. [PMID: 34324494 PMCID: PMC8354456 DOI: 10.1371/journal.pcbi.1009231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 08/10/2021] [Accepted: 06/30/2021] [Indexed: 11/19/2022] Open
Abstract
We describe a mathematical model for the aggregation of starved first-stage C elegans larvae (L1s). We propose that starved L1s produce and respond chemotactically to two labile diffusible chemical signals, a short-range attractant and a longer range repellent. This model takes the mathematical form of three coupled partial differential equations, one that describes the movement of the worms and one for each of the chemical signals. Numerical solution of these equations produced a pattern of aggregates that resembled that of worm aggregates observed in experiments. We also describe the identification of a sensory receptor gene, srh-2, whose expression is induced under conditions that promote L1 aggregation. Worms whose srh-2 gene has been knocked out form irregularly shaped aggregates. Our model suggests this phenotype may be explained by the mutant worms slowing their movement more quickly than the wild type.
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Affiliation(s)
- Leon Avery
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
| | - Brian Ingalls
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
| | - Catherine Dumur
- Department of Pathology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Alexander Artyukhin
- Chemistry Department, State University of New York, College of Environmental Science and Forestry, Syracuse, New York, United States of America
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Ortiz A, Vega NM, Ratzke C, Gore J. Interspecies bacterial competition regulates community assembly in the C. elegans intestine. THE ISME JOURNAL 2021; 15:2131-2145. [PMID: 33589765 PMCID: PMC8245486 DOI: 10.1038/s41396-021-00910-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 01/31/2023]
Abstract
From insects to mammals, a large variety of animals hold in their intestines complex bacterial communities that play an important role in health and disease. To further our understanding of how intestinal bacterial communities assemble and function, we study the C. elegans microbiota with a bottom-up approach by feeding this nematode with bacterial monocultures as well as mixtures of two to eight bacterial species. We find that bacteria colonizing well in monoculture do not always do well in co-cultures due to interspecies bacterial interactions. Moreover, as community diversity increases, the ability to colonize the worm gut in monoculture becomes less important than interspecies interactions for determining community assembly. To explore the role of host-microbe adaptation, we compare bacteria isolated from C. elegans intestines and non-native isolates, and we find that the success of colonization is determined more by a species' taxonomy than by the isolation source. Lastly, by comparing the assembled microbiotas in two C. elegans mutants, we find that innate immunity via the p38 MAPK pathway decreases bacterial abundances yet has little influence on microbiota composition. These results highlight that bacterial interspecies interactions, more so than host-microbe adaptation or gut environmental filtering, play a dominant role in the assembly of the C. elegans microbiota.
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Affiliation(s)
- Anthony Ortiz
- grid.116068.80000 0001 2341 2786Physics of Living Systems, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA ,grid.116068.80000 0001 2341 2786Microbiology Graduate Program, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Nicole M. Vega
- grid.116068.80000 0001 2341 2786Physics of Living Systems, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA ,grid.189967.80000 0001 0941 6502Present Address: Department of Biology, Emory University, Atlanta, GA USA
| | - Christoph Ratzke
- grid.116068.80000 0001 2341 2786Physics of Living Systems, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA ,grid.10392.390000 0001 2190 1447Present Address: Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), Cluster of Excellence ‘CMFI’, University of Tübingen, Tübingen, Germany
| | - Jeff Gore
- grid.116068.80000 0001 2341 2786Physics of Living Systems, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA ,grid.116068.80000 0001 2341 2786Microbiology Graduate Program, Massachusetts Institute of Technology, Cambridge, MA USA
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Fueser H, Rauchschwalbe MT, Höss S, Traunspurger W. Food bacteria and synthetic microparticles of similar size influence pharyngeal pumping of Caenorhabditis elegans. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2021; 235:105827. [PMID: 33882407 DOI: 10.1016/j.aquatox.2021.105827] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 06/12/2023]
Abstract
Toxicity tests using the model organism Caenorhabditis elegans have shown that exposure to small microplastics such as polystyrene (PS) beads lead to high body burdens and dietary restrictions that in turn inhibit reproduction. Pharyngeal pumping is the key mechanism of C. elegans for governing the uptake of food and other particles and can be easily monitored by determining the pumping rates. In this study, pharyngeal pumping of C. elegans was examined in response to increasing quantities of food bacteria (E. coli: 106-1010 cells ml-1) and synthetic particles (107-109 beads ml-1) of similar size (1 µm). While the average pumping rate of C. elegans exposed to E. coli depended on the density of the bacterial cells, this was not the case for the synthetic beads. At 107 items ml-1, bacterial cells and synthetic beads triggered a basic stimulation of the pumping rate, independent of the nutritional value of the particle. At quantities >107 items ml-1, however, the nutritional value was essential to maximize the pumping rate, as it was upregulated only by E. coli cells, which can be chemosensorially recognized by C. elegans. Given the unselective uptake of all particles in the size range of bacteria, restricting the pumping rates for particles with low nutritional value to a basic rate, prevents the nematodes from wasting energy by high-frequency pumping, but still allows a food-quality screening at low food levels.
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Affiliation(s)
- Hendrik Fueser
- Bielefeld University, Animal Ecology, Konsequenz 45, 33615 Bielefeld, Germany.
| | | | - Sebastian Höss
- Bielefeld University, Animal Ecology, Konsequenz 45, 33615 Bielefeld, Germany; Ecossa, Giselastr. 6, 82319 Starnberg, Germany
| | - Walter Traunspurger
- Bielefeld University, Animal Ecology, Konsequenz 45, 33615 Bielefeld, Germany
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Cho JY, Choi TW, Kim SH, Ahnn J, Lee SK. Morphological Characterization of small, dumpy, and long Phenotypes in Caenorhabditis elegans. Mol Cells 2021; 44:160-167. [PMID: 33692220 PMCID: PMC8019597 DOI: 10.14348/molcells.2021.2236] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/18/2021] [Accepted: 02/22/2021] [Indexed: 11/27/2022] Open
Abstract
The determinant factors of an organism's size during animal development have been explored from various angles but remain partially understood. In Caenorhabditis elegans, many genes affecting cuticle structure, cell growth, and proliferation have been identified to regulate the worm's overall morphology, including body size. While various mutations in those genes directly result in changes in the morphological phenotypes, there is still a need for established, clear, and distinct standards to determine the apparent abnormality in a worm's size and shape. In this study, we measured the body length, body width, terminal bulb length, and head size of mutant worms with reported Dumpy (Dpy), Small (Sma) or Long (Lon) phenotypes by plotting and comparing their respective ratios of various parameters. These results show that the Sma phenotypes are proportionally smaller overall with mild stoutness, and Dpy phenotypes are significantly stouter and have disproportionally small head size. This study provides a standard platform for determining morphological phenotypes designating and annotating mutants that exhibit body shape variations, defining the morphological phenotype of previously unexamined mutants.
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Affiliation(s)
- Joshua Young Cho
- Department of Life Science, School of Natural Sciences, Hanyang University, Seoul 04763, Korea
- BK21 PLUS Life Science for BDR Team, Hanyang University, Seoul 04763, Korea
- Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea
- Present address: Doctor of Dental Surgery Program, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, CA 94103, USA
| | - Tae-Woo Choi
- Department of Life Science, School of Natural Sciences, Hanyang University, Seoul 04763, Korea
- BK21 PLUS Life Science for BDR Team, Hanyang University, Seoul 04763, Korea
- Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea
- Present address: Macrogen Inc., Seoul 08511, Korea
| | - Seung Hyun Kim
- Department of Life Science, School of Natural Sciences, Hanyang University, Seoul 04763, Korea
- Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Joohong Ahnn
- Department of Life Science, School of Natural Sciences, Hanyang University, Seoul 04763, Korea
- BK21 PLUS Life Science for BDR Team, Hanyang University, Seoul 04763, Korea
- Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Sun-Kyung Lee
- Department of Life Science, School of Natural Sciences, Hanyang University, Seoul 04763, Korea
- BK21 PLUS Life Science for BDR Team, Hanyang University, Seoul 04763, Korea
- Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea
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Gerhard AP, Krücken J, Neveu C, Charvet CL, Harmache A, von Samson-Himmelstjerna G. Pharyngeal Pumping and Tissue-Specific Transgenic P-Glycoprotein Expression Influence Macrocyclic Lactone Susceptibility in Caenorhabditis elegans. Pharmaceuticals (Basel) 2021; 14:153. [PMID: 33668460 PMCID: PMC7917992 DOI: 10.3390/ph14020153] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/04/2021] [Accepted: 02/09/2021] [Indexed: 11/16/2022] Open
Abstract
Macrocyclic lactones (MLs) are widely used drugs to treat and prevent parasitic nematode infections. In many nematode species including a major pathogen of foals, Parascaris univalens, resistance against MLs is widespread, but the underlying resistance mechanisms and ML penetration routes into nematodes remain unknown. Here, we examined how the P-glycoprotein efflux pumps, candidate genes for ML resistance, can modulate drug susceptibility and investigated the role of active drug ingestion for ML susceptibility in the model nematode Caenorhabditis elegans. Wildtype or transgenic worms, modified to overexpress P. univalens PGP-9 (Pun-PGP-9) at the intestine or epidermis, were incubated with ivermectin or moxidectin in the presence (bacteria or serotonin) or absence (no specific stimulus) of pharyngeal pumping (PP). Active drug ingestion by PP was identified as an important factor for ivermectin susceptibility, while moxidectin susceptibility was only moderately affected. Intestinal Pun-PGP-9 expression elicited a protective effect against ivermectin and moxidectin only in the presence of PP stimulation. Conversely, epidermal Pun-PGP-9 expression protected against moxidectin regardless of PP and against ivermectin only in the absence of active drug ingestion. Our results demonstrate the role of active drug ingestion by nematodes for susceptibility and provide functional evidence for the contribution of P-glycoproteins to ML resistance in a tissue-specific manner.
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Affiliation(s)
- Alexander P. Gerhard
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, 14163 Berlin, Germany; (A.P.G.); (J.K.)
| | - Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, 14163 Berlin, Germany; (A.P.G.); (J.K.)
| | - Cedric Neveu
- INRAE, Université de Tours, ISP, F-37380 Nouzilly, France; (C.N.); (C.L.C.); (A.H.)
| | - Claude L. Charvet
- INRAE, Université de Tours, ISP, F-37380 Nouzilly, France; (C.N.); (C.L.C.); (A.H.)
| | - Abdallah Harmache
- INRAE, Université de Tours, ISP, F-37380 Nouzilly, France; (C.N.); (C.L.C.); (A.H.)
| | - Georg von Samson-Himmelstjerna
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, 14163 Berlin, Germany; (A.P.G.); (J.K.)
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32
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Mata-Cabana A, Pérez-Nieto C, Olmedo M. Nutritional control of postembryonic development progression and arrest in Caenorhabditis elegans. ADVANCES IN GENETICS 2020; 107:33-87. [PMID: 33641748 DOI: 10.1016/bs.adgen.2020.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Developmental programs are under strict genetic control that favors robustness of the process. In order to guarantee the same outcome in different environmental situations, development is modulated by input pathways, which inform about external conditions. In the nematode Caenorhabditis elegans, the process of postembryonic development involves a series of stereotypic cell divisions, the progression of which is controlled by the nutritional status of the animal. C. elegans can arrest development at different larval stages, leading to cell arrest of the relevant divisions of the stage. This means that studying the nutritional control of development in C. elegans we can learn about the mechanisms controlling cell division in an in vivo model. In this work, we reviewed the current knowledge about the nutrient sensing pathways that control the progression or arrest of development in response to nutrient availability, with a special focus on the arrest at the L1 stage.
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Affiliation(s)
- Alejandro Mata-Cabana
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Avd. Reina Mercedes, Sevilla, Spain
| | - Carmen Pérez-Nieto
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Avd. Reina Mercedes, Sevilla, Spain
| | - María Olmedo
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Avd. Reina Mercedes, Sevilla, Spain.
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33
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Fueser H, Mueller MT, Traunspurger W. Rapid ingestion and egestion of spherical microplastics by bacteria-feeding nematodes. CHEMOSPHERE 2020; 261:128162. [PMID: 33113662 DOI: 10.1016/j.chemosphere.2020.128162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/13/2020] [Accepted: 08/17/2020] [Indexed: 06/11/2023]
Abstract
Microplastics, anthropogenically released into freshwaters, settle in sediments, where they are directly ingested by benthic organisms. However, to the best of our knowledge, fine-scale studies of microplastic ingestion and egestion by nematodes, one of the most abundant meiofaunal taxa, are lacking. We therefore conducted a time series of the ingestion and egestion by adult Caenorhabditis elegans and Pristionchus pacificus of 0.5- and 1.0-μm fluorescent polystyrene (PS) beads along with bacteria. The nematodes were exposed to 107 beads ml-1 in aqueous medium for 5 min-24 h and pumping rates of C. elegans were determined. In the egestion study, PS bead egestion was monitored in nematodes with high microplastic body burdens for 5 min-24 h in microplastic-free medium. Ingested beads were detected already within 5 min and up to 203 ± 15 PS beads (1.0 μm; C. elegans) were found after 30 min. Overall, significantly more 1.0-μm than 0.5-μm PS beads were taken up. The distinct feeding behaviors of the two species influenced their PS bead body burdens. Ingested PS beads were almost completely egested within the first 20-40 min in the presence of sufficient food. In C. elegans, 1.0-μm beads were egested less rapidly than 0.5-μm PS beads. Given the rapid ingestion and egestion of the beads, our study demonstrates that the actual amount of ingested and egested microplastics by nematodes in the environment may be several times higher than the microplastic body burdens may imply. However, spherical PS beads did not bioconcentrate in nematodes.
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Affiliation(s)
- Hendrik Fueser
- Bielefeld University, Animal Ecology, Konsequenz 45, 33615, Bielefeld, Germany.
| | | | - Walter Traunspurger
- Bielefeld University, Animal Ecology, Konsequenz 45, 33615, Bielefeld, Germany
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Deficiency of Inositol Monophosphatase Activity Decreases Phosphoinositide Lipids and Enhances TRPV1 Function In Vivo. J Neurosci 2020; 41:408-423. [PMID: 33239401 PMCID: PMC7821860 DOI: 10.1523/jneurosci.0803-20.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 11/12/2020] [Accepted: 11/19/2020] [Indexed: 11/21/2022] Open
Abstract
Membrane remodeling by inflammatory mediators influences the function of sensory ion channels. The capsaicin- and heat-activated transient receptor potential vanilloid 1 (TRPV1) channel contributes to neurogenic inflammation and pain hypersensitivity, in part because of its potentiation downstream of phospholipase C-coupled receptors that regulate phosphoinositide lipid content. Here, we determined the effect of phosphoinositide lipids on TRPV1 function by combining genetic dissection, diet supplementation, and behavioral, biochemical, and functional analyses in Caenorhabditis elegans As capsaicin elicits heat and pain sensations in mammals, transgenic TRPV1 worms exhibit an aversive response to capsaicin. TRPV1 worms with low levels of phosphoinositide lipids display an enhanced response to capsaicin, whereas phosphoinositide lipid supplementation reduces TRPV1-mediated responses. A worm carrying a TRPV1 construct lacking the distal C-terminal domain features an enhanced response to capsaicin, independent of the phosphoinositide lipid content. Our results demonstrate that TRPV1 activity is enhanced when the phosphoinositide lipid content is reduced, and the C-terminal domain is key to determining agonist response in vivo.
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Izquierdo PG, O'Connor V, Green AC, Holden-Dye L, Tattersall JEH. C. elegans pharyngeal pumping provides a whole organism bio-assay to investigate anti-cholinesterase intoxication and antidotes. Neurotoxicology 2020; 82:50-62. [PMID: 33176172 DOI: 10.1016/j.neuro.2020.11.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 10/30/2020] [Accepted: 11/03/2020] [Indexed: 10/23/2022]
Abstract
Inhibition of acetylcholinesterase by either organophosphates or carbamates causes anti-cholinesterase poisoning. This arises through a wide range of neurotoxic effects triggered by the overstimulation of the cholinergic receptors at synapses and neuromuscular junctions. Without intervention, this poisoning can lead to profound toxic effects, including death, and the incomplete efficacy of the current treatments, particularly for oxime-insensitive agents, provokes the need to find better antidotes. Here we show how the non-parasitic nematode Caenorhabditis elegans offers an excellent tool for investigating the acetylcholinesterase intoxication. The C. elegans neuromuscular junctions show a high degree of molecular and functional conservation with the cholinergic transmission that operates in the autonomic, central and neuromuscular synapses in mammals. In fact, the anti-cholinesterase intoxication of the worm's body wall neuromuscular junction has been unprecedented in understanding molecular determinants of cholinergic function in nematodes and other organisms. We extend the use of the model organism's feeding behaviour as a tool to investigate carbamate and organophosphate mode of action. We show that inhibition of the cholinergic-dependent rhythmic pumping of the pharyngeal muscle correlates with the inhibition of the acetylcholinesterase activity caused by aldicarb, paraoxons and DFP exposure. Further, this bio-assay allows one to address oxime dependent reversal of cholinesterase inhibition in the context of whole organism recovery. Interestingly, the recovery of the pharyngeal function after such anti-cholinesterase poisoning represents a sensitive and easily quantifiable phenotype that is indicative of the spontaneous recovery or irreversible modification of the worm acetylcholinesterase after inhibition. These observations highlight the pharynx of C. elegans as a new tractable approach to explore anti-cholinesterase intoxication and recovery with the potential to resolve critical genetic determinants of these neurotoxins' mode of action.
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Affiliation(s)
- Patricia G Izquierdo
- Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom.
| | - Vincent O'Connor
- Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - A Christopher Green
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, SP4 0JQ, United Kingdom
| | - Lindy Holden-Dye
- Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - John E H Tattersall
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, SP4 0JQ, United Kingdom
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Stuhr NL, Curran SP. Bacterial diets differentially alter lifespan and healthspan trajectories in C. elegans. Commun Biol 2020; 3:653. [PMID: 33159120 PMCID: PMC7648844 DOI: 10.1038/s42003-020-01379-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 10/14/2020] [Indexed: 01/21/2023] Open
Abstract
Diet is one of the more variable aspects in life due to the variety of options that organisms are exposed to in their natural habitats. In the laboratory, C. elegans are raised on bacterial monocultures, traditionally the E. coli B strain OP50, and spontaneously occurring microbial contaminants are removed to limit experimental variability because diet-including the presence of contaminants-can exert a potent influence over animal physiology. In order to diversify the menu available to culture C. elegans in the lab, we have isolated and cultured three such microbes: Methylobacterium, Xanthomonas, and Sphingomonas. The nutritional composition of these bacterial foods is unique, and when fed to C. elegans, can differentially alter multiple life history traits including development, reproduction, and metabolism. In light of the influence each food source has on specific physiological attributes, we comprehensively assessed the impact of these bacteria on animal health and devised a blueprint for utilizing different food combinations over the lifespan, in order to promote longevity. The expansion of the bacterial food options to use in the laboratory will provide a critical tool to better understand the complexities of bacterial diets and subsequent changes in physiology and gene expression.
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Affiliation(s)
- Nicole L Stuhr
- Leonard Davis School of Gerontology, University of Southern California, 3715 McClintock Ave, Los Angeles, CA, 90089, USA
- Dornsife College of Letters, Arts, and Science, Department of Molecular and Computational Biology, University of Southern California, 1050 Childs Way, Los Angeles, CA, 90089, USA
| | - Sean P Curran
- Leonard Davis School of Gerontology, University of Southern California, 3715 McClintock Ave, Los Angeles, CA, 90089, USA.
- Dornsife College of Letters, Arts, and Science, Department of Molecular and Computational Biology, University of Southern California, 1050 Childs Way, Los Angeles, CA, 90089, USA.
- Norris Comprehensive Cancer Center, University of Southern California, 1441 Eastlake Ave, Los Angeles, CA, 90033, USA.
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37
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Abstract
Caenorhabditis elegans' behavioral states, like those of other animals, are shaped by its immediate environment, its past experiences, and by internal factors. We here review the literature on C. elegans behavioral states and their regulation. We discuss dwelling and roaming, local and global search, mate finding, sleep, and the interaction between internal metabolic states and behavior.
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Affiliation(s)
- Steven W Flavell
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - David M Raizen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Young-Jai You
- Division of Biological Science, Graduate School of Science, Nagoya University, 464-8602, Japan
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38
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Goswamy D, Irazoqui JE. A unifying hypothesis on the central role of reactive oxygen species in bacterial pathogenesis and host defense in C. elegans. Curr Opin Immunol 2020; 68:9-20. [PMID: 32898751 DOI: 10.1016/j.coi.2020.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/10/2020] [Accepted: 08/12/2020] [Indexed: 01/06/2023]
Abstract
During intestinal infection, microbes induce ROS by various mechanisms in C. elegans. ROS can have beneficial roles, acting as antimicrobials and as signaling molecules that activate cytoprotective pathways. Failure to maintain appropriate levels of ROS causes oxidative stress and cellular damage. This review uses the Damage Response Framework to interpret several recent observations on the relationships between infection, host response, and host damage, with a focus on mechanisms mediated by ROS. We propose a unifying hypothesis that ROS drive a collapse in proteostasis in infected C. elegans, which results in death during unresolved infection. Because the signaling pathways highlighted here are conserved in mammals, the mentioned and future studies can provide new tools of hypothesis generation in human health and disease.
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Affiliation(s)
- Debanjan Goswamy
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605, United States; Immunology and Microbiology Program, University of Massachusetts Medical School, Worcester, MA 01605, United States
| | - Javier E Irazoqui
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605, United States; Immunology and Microbiology Program, University of Massachusetts Medical School, Worcester, MA 01605, United States.
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39
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Quach KT, Chalasani SH. Intraguild predation between Pristionchus pacificus and Caenorhabditis elegans: a complex interaction with the potential for aggressive behaviour. J Neurogenet 2020; 34:404-419. [PMID: 33054476 PMCID: PMC7836027 DOI: 10.1080/01677063.2020.1833004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 07/20/2020] [Indexed: 12/20/2022]
Abstract
The related nematodes Pristionchus pacificus and Caenorhabditis elegans both eat bacteria for nutrition and are therefore competitors when they exploit the same bacterial resource. In addition to competing with each other, P. pacificus is a predator of C. elegans larval prey. These two relationships together form intraguild predation, which is the killing and sometimes eating of potential competitors. In killing C. elegans, the intraguild predator P. pacificus may achieve dual benefits of immediate nutrition and reduced competition for bacteria. Recent studies of P. pacificus have characterized many aspects of its predatory biting behaviour as well as underlying molecular and genetic mechanisms. However, little has been explored regarding the potentially competitive aspect of P. pacificus biting C. elegans. Moreover, aggression may also be implicated if P. pacificus intentionally bites C. elegans with the goal of reducing competition for bacteria. The aim of this review is to broadly outline how aggression, predation, and intraguild predation relate to each other, as well as how these concepts may be applied to future studies of P. pacificus in its interactions with C. elegans.
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Affiliation(s)
- Kathleen T. Quach
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Sreekanth H. Chalasani
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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40
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Suzuki Y, Kikuchi K, Numayama-Tsuruta K, Ishikawa T. How do Caenorhabditis elegans worms survive in highly viscous habitats? J Exp Biol 2020; 223:jeb224691. [PMID: 32587072 DOI: 10.1242/jeb.224691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 06/21/2020] [Indexed: 11/20/2022]
Abstract
The nematode Caenorhabditis elegans is a filter feeder that lives in various viscous habitats such as soil, the intestines of slugs, and rotting materials such as fruits and stems. Caenorhabditis elegans draws in suspensions of bacteria and separates bacteria from water using the pharyngeal pump. Although these worms often live in highly viscous habitats, it is still unclear how they survive in these environments by eating bacteria. In this study, we investigated the effects of suspension viscosity on the survival rate of malnourished worms by combining live imaging and scaling analyses. We found that survival rate decreased with increases in viscosity because the high viscosity suppressed the amount of food ingested. The same tendency was found in two feeding-defective mutants, eat-6(ad467) and eat-6(ad997). We also found that the high viscosity weakened pump function, but the velocities in the pharynx were not zero, even in the most viscous suspensions. Finally, we estimated the amount of ingested food using scaling analyses, which provided a master curve of the experimental survival rates. These results illustrate that the survival rate of C. elegans worms is strongly dependent on the ingested bacteria per unit time associated with physical environments, such as the viscosity of food suspensions and the cell density of bacteria. The pump function of the C. elegans pharynx is not completely lost even in fluids that have 105 times higher viscosity than water, which may contribute to their ability to survive around the world in highly viscous environments.
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Affiliation(s)
- Yuki Suzuki
- Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai, Miyagi 980-8579, Japan
| | - Kenji Kikuchi
- Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai, Miyagi 980-8579, Japan
- Graduate School of Biomedical Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai, Miyagi 980-8579, Japan
| | - Keiko Numayama-Tsuruta
- Graduate School of Biomedical Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai, Miyagi 980-8579, Japan
| | - Takuji Ishikawa
- Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai, Miyagi 980-8579, Japan
- Graduate School of Biomedical Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai, Miyagi 980-8579, Japan
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41
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O'Donnell MP, Fox BW, Chao PH, Schroeder FC, Sengupta P. A neurotransmitter produced by gut bacteria modulates host sensory behaviour. Nature 2020; 583:415-420. [PMID: 32555456 PMCID: PMC7853625 DOI: 10.1038/s41586-020-2395-5] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 03/27/2020] [Indexed: 12/18/2022]
Abstract
Animals coexist in commensal, pathogenic or mutualistic relationships with complex communities of diverse organisms, including microorganisms1. Some bacteria produce bioactive neurotransmitters that have previously been proposed to modulate nervous system activity and behaviours of their hosts2,3. However, the mechanistic basis of this microbiota-brain signalling and its physiological relevance are largely unknown. Here we show that in Caenorhabditis elegans, the neuromodulator tyramine produced by commensal Providencia bacteria, which colonize the gut, bypasses the requirement for host tyramine biosynthesis and manipulates a host sensory decision. Bacterially produced tyramine is probably converted to octopamine by the host tyramine β-hydroxylase enzyme. Octopamine, in turn, targets the OCTR-1 octopamine receptor on ASH nociceptive neurons to modulate an aversive olfactory response. We identify the genes that are required for tyramine biosynthesis in Providencia, and show that these genes are necessary for the modulation of host behaviour. We further find that C. elegans colonized by Providencia preferentially select these bacteria in food choice assays, and that this selection bias requires bacterially produced tyramine and host octopamine signalling. Our results demonstrate that a neurotransmitter produced by gut bacteria mimics the functions of the cognate host molecule to override host control of a sensory decision, and thereby promotes fitness of both the host and the microorganism.
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Affiliation(s)
| | - Bennett W Fox
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Pin-Hao Chao
- Department of Biology, Brandeis University, Waltham, MA, USA
| | - Frank C Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA, USA.
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42
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Silva MH. Effects of low‐dose chlorpyrifos on neurobehavior and potential mechanisms: A review of studies in rodents, zebrafish, and
Caenorhabditis elegans. Birth Defects Res 2020; 112:445-479. [DOI: 10.1002/bdr2.1661] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/10/2020] [Accepted: 02/12/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Marilyn H. Silva
- Retired from a career in regulatory toxicology and risk assessment
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43
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Urrutia A, García-Angulo VA, Fuentes A, Caneo M, Legüe M, Urquiza S, Delgado SE, Ugalde J, Burdisso P, Calixto A. Bacterially produced metabolites protect C. elegans neurons from degeneration. PLoS Biol 2020; 18:e3000638. [PMID: 32208418 PMCID: PMC7092960 DOI: 10.1371/journal.pbio.3000638] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 02/18/2020] [Indexed: 12/20/2022] Open
Abstract
Caenorhabditis elegans and its cognate bacterial diet comprise a reliable, widespread model to study diet and microbiota effects on host physiology. Nonetheless, how diet influences the rate at which neurons die remains largely unknown. A number of models have been used in C. elegans as surrogates for neurodegeneration. One of these is a C. elegans strain expressing a neurotoxic allele of the mechanosensory abnormality protein 4 (MEC-4d) degenerin/epithelial Na+ (DEG/ENaC) channel, which causes the progressive degeneration of the touch receptor neurons (TRNs). Using this model, our study evaluated the effect of various dietary bacteria on neurodegeneration dynamics. Although degeneration of TRNs was steady and completed at adulthood in the strain routinely used for C. elegans maintenance (Escherichia coli OP50), it was significantly reduced in environmental and other laboratory bacterial strains. Strikingly, neuroprotection reached more than 40% in the E. coli HT115 strain. HT115 protection was long lasting well into old age of animals and was not restricted to the TRNs. Small amounts of HT115 on OP50 bacteria as well as UV-killed HT115 were still sufficient to produce neuroprotection. Early growth of worms in HT115 protected neurons from degeneration during later growth in OP50. HT115 diet promoted the nuclear translocation of DAF-16 (ortholog of the FOXO family of transcription factors), a phenomenon previously reported to underlie neuroprotection caused by down-regulation of the insulin receptor in this system. Moreover, a daf-16 loss-of-function mutation abolishes HT115-driven neuroprotection. Comparative genomics, transcriptomics, and metabolomics approaches pinpointed the neurotransmitter γ-aminobutyric acid (GABA) and lactate as metabolites differentially produced between E. coli HT115 and OP50. HT115 mutant lacking glutamate decarboxylase enzyme genes (gad), which catalyze the conversion of GABA from glutamate, lost the ability to produce GABA and also to stop neurodegeneration. Moreover, in situ GABA supplementation or heterologous expression of glutamate decarboxylase in E. coli OP50 conferred neuroprotective activity to this strain. Specific C. elegans GABA transporters and receptors were required for full HT115-mediated neuroprotection. Additionally, lactate supplementation also increased anterior ventral microtubule (AVM) neuron survival in OP50. Together, these results demonstrate that bacterially produced GABA and other metabolites exert an effect of neuroprotection in the host, highlighting the role of neuroactive compounds of the diet in nervous system homeostasis.
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Affiliation(s)
- Arles Urrutia
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago de Chile, Chile
| | - Víctor A. García-Angulo
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago de Chile, Chile
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago de Chile, Chile
| | - Andrés Fuentes
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago de Chile, Chile
| | - Mauricio Caneo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago de Chile, Chile
| | - Marcela Legüe
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago de Chile, Chile
| | - Sebastián Urquiza
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago de Chile, Chile
| | - Scarlett E. Delgado
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago de Chile, Chile
| | - Juan Ugalde
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago de Chile, Chile
| | - Paula Burdisso
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario and Plataforma Argentina de Biología Estructural y Metabolómica (PLABEM), Rosario, Santa Fe, Argentina
| | - Andrea Calixto
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago de Chile, Chile
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44
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Ding SS, Romenskyy M, Sarkisyan KS, Brown AEX. Measuring Caenorhabditis elegans Spatial Foraging and Food Intake Using Bioluminescent Bacteria. Genetics 2020; 214:577-587. [PMID: 31911453 PMCID: PMC7054024 DOI: 10.1534/genetics.119.302804] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 01/06/2020] [Indexed: 01/08/2023] Open
Abstract
For most animals, feeding includes two behaviors: foraging to find a food patch and food intake once a patch is found. The nematode Caenorhabditis elegans is a useful model for studying the genetics of both behaviors. However, most methods of measuring feeding in worms quantify either foraging behavior or food intake, but not both. Imaging the depletion of fluorescently labeled bacteria provides information on both the distribution and amount of consumption, but even after patch exhaustion a prominent background signal remains, which complicates quantification. Here, we used a bioluminescent Escherichia coli strain to quantify C. elegans feeding. With light emission tightly coupled to active metabolism, only living bacteria are capable of bioluminescence, so the signal is lost upon ingestion. We quantified the loss of bioluminescence using N2 reference worms and eat-2 mutants, and found a nearly 100-fold increase in signal-to-background ratio and lower background compared to loss of fluorescence. We also quantified feeding using aggregating npr-1 mutant worms. We found that groups of npr-1 mutants first clear bacteria from within the cluster before foraging collectively for more food; similarly, during large population swarming, only worms at the migrating front are in contact with bacteria. These results demonstrate the usefulness of bioluminescent bacteria for quantifying feeding and generating insights into the spatial pattern of food consumption.
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Affiliation(s)
- Siyu Serena Ding
- Institute of Clinical Sciences, Imperial College London, London W12 0NN, United Kingdom
- Medical Research Council London Institute of Medical Sciences, London W12 0NN, United Kingdom
| | - Maksym Romenskyy
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Karen S Sarkisyan
- Institute of Clinical Sciences, Imperial College London, London W12 0NN, United Kingdom
- Medical Research Council London Institute of Medical Sciences, London W12 0NN, United Kingdom
| | - Andre E X Brown
- Institute of Clinical Sciences, Imperial College London, London W12 0NN, United Kingdom
- Medical Research Council London Institute of Medical Sciences, London W12 0NN, United Kingdom
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45
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Scott E, Holden-Dye L, O'Connor V, Wand ME. Intra Strain Variation of the Effects of Gram-Negative ESKAPE Pathogens on Intestinal Colonization, Host Viability, and Host Response in the Model Organism Caenorhabditis elegans. Front Microbiol 2020; 10:3113. [PMID: 32038555 PMCID: PMC6985274 DOI: 10.3389/fmicb.2019.03113] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/24/2019] [Indexed: 01/21/2023] Open
Abstract
In its native environment of rotting vegetation, the soil nematode Caenorhabditis elegans encounters a range of bacteria. This includes species from the ESKAPE group of pathogens that pose a clinical problem in acquired hospital infections. Here, we investigated three Gram-negative members of the ESKAPE group, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. Pathogenicity profiles as measured by time to kill adult C. elegans showed that P. aeruginosa was the most pathogenic, followed by K. pneumoniae, while C. elegans cultured on A. baumannii exhibited the same survival as those on the standard laboratory food source for C. elegans, Escherichia coli OP50. The pathogenicity was paralleled by a reduction in time that C. elegans resided on the bacterial lawn with the most pathogenic strains triggering an increase in the frequency of food-leaving. Previous reports indicate that gut colonization is a feature of pathogenicity, but we found that the most pathogenic strains were not associated with the highest level of colonization. Indeed, clearance of P. aeruginosa strains from the C. elegans gut was independent of bacterial pathogenicity. We show that this clearance is regulated by neuromodulation as C. elegans mutants in unc-31 and egl-3 have enhanced clearance of P. aeruginosa. Intriguingly this is also not linked to their pathogenicity. It is likely that there is a dynamic balance occurring in the C. elegans intestinal environment between maintaining a healthy, beneficial microbiota and removal of pathogenic bacteria.
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Affiliation(s)
- Euan Scott
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Lindy Holden-Dye
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Vincent O'Connor
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Matthew E Wand
- National Infection Service, Public Health England, Salisbury, United Kingdom
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46
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Rutter JW, Ozdemir T, Galimov ER, Quintaneiro LM, Rosa L, Thomas GM, Cabreiro F, Barnes CP. Detecting Changes in the Caenorhabditis elegans Intestinal Environment Using an Engineered Bacterial Biosensor. ACS Synth Biol 2019; 8:2620-2628. [PMID: 31657907 PMCID: PMC6929061 DOI: 10.1021/acssynbio.9b00166] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Indexed: 12/12/2022]
Abstract
Caenorhabditis elegans has become a key model organism within biology. In particular, the transparent gut, rapid growing time, and ability to create a defined gut microbiota make it an ideal candidate organism for understanding and engineering the host microbiota. Here we present the development of an experimental model that can be used to characterize whole-cell bacterial biosensors in vivo. A dual-plasmid sensor system responding to isopropyl β-d-1-thiogalactopyranoside was developed and fully characterized in vitro. Subsequently, we show that the sensor was capable of detecting and reporting on changes in the intestinal environment of C. elegans after introducing an exogenous inducer into the environment. The protocols presented here may be used to aid the rational design of engineered bacterial circuits, primarily for diagnostic applications. In addition, the model system may serve to reduce the use of current animal models and aid in the exploration of complex questions within general nematode and host-microbe biology.
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Affiliation(s)
- Jack W. Rutter
- Department
of Cell and Developmental Biology, University
College London, London WC1E 6BT, United Kingdom
| | - Tanel Ozdemir
- Department
of Cell and Developmental Biology, University
College London, London WC1E 6BT, United Kingdom
| | - Evgeniy R. Galimov
- MRC
London Institute of Medical Sciences, London W12 0NN, United
Kingdom
| | - Leonor M. Quintaneiro
- Institute
of Structural and Molecular Biology, University
College London and Birkbeck College, London WC1E 6BT, United
Kingdom
| | - Luca Rosa
- Department
of Cell and Developmental Biology, University
College London, London WC1E 6BT, United Kingdom
| | - Geraint M. Thomas
- Department
of Cell and Developmental Biology, University
College London, London WC1E 6BT, United Kingdom
| | - Filipe Cabreiro
- MRC
London Institute of Medical Sciences, London W12 0NN, United
Kingdom
- Institute
of Structural and Molecular Biology, University
College London and Birkbeck College, London WC1E 6BT, United
Kingdom
| | - Chris P. Barnes
- Department
of Cell and Developmental Biology, University
College London, London WC1E 6BT, United Kingdom
- Department
of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
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47
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Bouagnon AD, Lin L, Srivastava S, Liu CC, Panda O, Schroeder FC, Srinivasan S, Ashrafi K. Intestinal peroxisomal fatty acid β-oxidation regulates neural serotonin signaling through a feedback mechanism. PLoS Biol 2019; 17:e3000242. [PMID: 31805041 PMCID: PMC6917301 DOI: 10.1371/journal.pbio.3000242] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 12/17/2019] [Accepted: 11/15/2019] [Indexed: 02/02/2023] Open
Abstract
The ability to coordinate behavioral responses with metabolic status is fundamental to the maintenance of energy homeostasis. In numerous species including Caenorhabditis elegans and mammals, neural serotonin signaling regulates a range of food-related behaviors. However, the mechanisms that integrate metabolic information with serotonergic circuits are poorly characterized. Here, we identify metabolic, molecular, and cellular components of a circuit that links peripheral metabolic state to serotonin-regulated behaviors in C. elegans. We find that blocking the entry of fatty acyl coenzyme As (CoAs) into peroxisomal β-oxidation in the intestine blunts the effects of neural serotonin signaling on feeding and egg-laying behaviors. Comparative genomics and metabolomics revealed that interfering with intestinal peroxisomal β-oxidation results in a modest global transcriptional change but significant changes to the metabolome, including a large number of changes in ascaroside and phospholipid species, some of which affect feeding behavior. We also identify body cavity neurons and an ether-a-go-go (EAG)-related potassium channel that functions in these neurons as key cellular components of the circuitry linking peripheral metabolic signals to regulation of neural serotonin signaling. These data raise the possibility that the effects of serotonin on satiety may have their origins in feedback, homeostatic metabolic responses from the periphery.
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Affiliation(s)
- Aude D. Bouagnon
- Department of Physiology, University of California San Francisco, San Francisco, California, United States of America
| | - Lin Lin
- Department of Physiology, University of California San Francisco, San Francisco, California, United States of America
| | - Shubhi Srivastava
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California, United States of America
| | - Chung-Chih Liu
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California, United States of America
| | - Oishika Panda
- Boyce Thompson Institute, Cornell University, Ithaca, New York, United States of America
| | - Frank C. Schroeder
- Boyce Thompson Institute, Cornell University, Ithaca, New York, United States of America
| | - Supriya Srinivasan
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California, United States of America
| | - Kaveh Ashrafi
- Department of Physiology, University of California San Francisco, San Francisco, California, United States of America
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48
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Tang B, Tong P, Xue KS, Williams PL, Wang JS, Tang L. High-throughput assessment of toxic effects of metal mixtures of cadmium(Cd), lead(Pb), and manganese(Mn) in nematode Caenorhabditis elegans. CHEMOSPHERE 2019; 234:232-241. [PMID: 31220657 DOI: 10.1016/j.chemosphere.2019.05.271] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/28/2019] [Accepted: 05/29/2019] [Indexed: 06/09/2023]
Abstract
Heavy metals, a class of persistent environmental toxicants, are harmful to human health. Cd and Pb are two of the most common toxic heavy metals that have been linked with cancers and malfunction of the nervous system. Notably, contamination of Mn usually coexisted with Cd and Pb in environmental and occupational settings. Studies regularly examined the toxic effects on individual metals; however, potential health and toxic effects of mixtures containing two or more heavy metals are unknown. Here, we investigated toxic effects of Cd, Pb, Mn, and their binary and ternary mixtures in the nematode Caenorhabdities elegans. The toxic outcomes, including effects on growth, reproduction, and feeding, were measured via high-throughput platform analysis. The transgenic strain BY250 with GFP in dopaminergic neurons was used to explore the neurodegenerative effects induced by single metals or their mixtures. The combination index(CI) for mixtures effect was calculated using isobolograms methods. Following the exposure, we found significant toxic effects in C. elegans. For single metals, the toxicity order for growth, reproduction, and feeding were Pb > Cd > Mn. For mixtures, the mixture of Cd + Mn induced a less than addictive effect in C. elegans, whereas the mixtures of Cd + Pb, Pb + Mn, and Cd + Pb + Mn induced greater-than-additive effects. Both single metals and their mixtures induced abnormality in dopaminergic neurons. These results showed combinative toxic and neurodegenerative effects of heavy metal mixtures, and future studies will focus on characterization of concentration-response patterns and identification of potential molecular mechanisms in C. elegans model.
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Affiliation(s)
- Bowen Tang
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, USA
| | - Ping Tong
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China
| | - Kathy S Xue
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, USA
| | - Phillip L Williams
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, USA
| | - Jia-Sheng Wang
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, USA
| | - Lili Tang
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, USA.
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Kamal M, Moshiri H, Magomedova L, Han D, Nguyen KCQ, Yeo M, Knox J, Bagg R, Won AM, Szlapa K, Yip CM, Cummins CL, Hall DH, Roy PJ. The marginal cells of the Caenorhabditis elegans pharynx scavenge cholesterol and other hydrophobic small molecules. Nat Commun 2019; 10:3938. [PMID: 31477732 PMCID: PMC6718421 DOI: 10.1038/s41467-019-11908-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 08/09/2019] [Indexed: 12/24/2022] Open
Abstract
The nematode Caenorhabditis elegans is a bacterivore filter feeder. Through the contraction of the worm’s pharynx, a bacterial suspension is sucked into the pharynx’s lumen. Excess liquid is then shunted out of the buccal cavity through ancillary channels made by surrounding marginal cells. We find that many worm-bioactive small molecules (a.k.a. wactives) accumulate inside of the marginal cells as crystals or globular spheres. Through screens for mutants that resist the lethality associated with one crystallizing wactive we identify a presumptive sphingomyelin-synthesis pathway that is necessary for crystal and sphere accumulation. We find that expression of sphingomyelin synthase 5 (SMS-5) in the marginal cells is not only sufficient for wactive accumulation but is also important for absorbing exogenous cholesterol, without which C. elegans cannot develop. We conclude that sphingomyelin-rich marginal cells act as a sink to scavenge important nutrients from filtered liquid that might otherwise be shunted back into the environment. The C. elegans nematode worm is a filter-feeder and requires dietary sources of cholesterol. Here, the authors show that the C. elegans pharynx works as a filter to scavenge hydrophobic small molecules from its surrounding liquid environment.
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Affiliation(s)
- Muntasir Kamal
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Houtan Moshiri
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Lilia Magomedova
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, ON, M5S 3M2, Canada
| | - Duhyun Han
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Ken C Q Nguyen
- Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, 10461, USA
| | - May Yeo
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Jessica Knox
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Rachel Bagg
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Amy M Won
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Karolina Szlapa
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Christopher M Yip
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Carolyn L Cummins
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, ON, M5S 3M2, Canada
| | - David H Hall
- Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, 10461, USA
| | - Peter J Roy
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada. .,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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Bell L, Cuddington K. A burrowing ecosystem engineer positively affects its microbial prey under stressful conditions. Ecol Evol 2019; 9:7704-7711. [PMID: 31346433 PMCID: PMC6635926 DOI: 10.1002/ece3.5324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/05/2019] [Accepted: 05/11/2019] [Indexed: 11/14/2022] Open
Abstract
Species that facilitate others under stressful conditions are often ecosystem engineers: organisms that modify or create physical habitat.However, the net effect of an engineering species on another depends on both the magnitude of the direct interactions (e.g., competition or predation) and the specific environmental context.We used a laboratory system to isolate the trophic and engineering impacts of a predator, the nematode Caenorhabditis remanei, on its prey, Escherichia coli under different levels of environmental stress. We predicted that under stressful surface conditions the nematodes would positively impact their prey by creating burrows which protected the bacteria.Colony plate counts of E. coli indicated that there was a stress-induced change in the net impact of nematodes on bacteria from neutral to positive. Predator engineering in the form of burrowing allowed larger bacteria populations to survive.We conclude that even in a simple two-species system a predator can positively impact prey via ecosystem engineering.
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Affiliation(s)
- Laura Bell
- Department of BiologyUniversity of WaterlooWaterlooOntarioCanada
| | - Kim Cuddington
- Department of BiologyUniversity of WaterlooWaterlooOntarioCanada
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