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Guckes KR, Yount TA, Steingard CH, Miyashiro TI. Quorum sensing inhibits interference competition among bacterial symbionts within a host. Curr Biol 2023; 33:4244-4251.e4. [PMID: 37689064 PMCID: PMC10592073 DOI: 10.1016/j.cub.2023.08.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/20/2023] [Accepted: 08/16/2023] [Indexed: 09/11/2023]
Abstract
The symbioses that animals form with bacteria play important roles in health and disease, but the molecular details underlying how bacterial symbionts initially assemble within a host remain unclear.1,2,3 The bioluminescent bacterium Vibrio fischeri establishes a light-emitting symbiosis with the Hawaiian bobtail squid Euprymna scolopes by colonizing specific epithelium-lined crypt spaces within a symbiotic organ called the light organ.4 Competition for these colonization sites occurs between different strains of V. fischeri, with the lancet-like type VI secretion system (T6SS) facilitating strong competitive interference that results in strain incompatibility within a crypt space.5,6 Although recent studies have identified regulators of this T6SS, how the T6SS is controlled as symbionts assemble in vivo remains unknown.7,8 Here, we show that T6SS activity is suppressed by N-octanoyl-L-homoserine lactone (C8 HSL), which is a signaling molecule that facilitates quorum sensing in V. fischeri and is important for efficient symbiont assembly.9,10 We find that this signaling depends on the quorum-sensing regulator LitR, which lowers expression of the needle subunit Hcp, a key component of the T6SS, by repressing transcription of the T6SS regulator VasH. We show that LitR-dependent quorum sensing inhibits strain incompatibility within the squid light organ. Collectively, these results provide new insights into the mechanisms by which regulatory networks that promote symbiosis also control competition among symbionts, which in turn may affect the overall symbiont diversity that assembles within a host.
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Affiliation(s)
- Kirsten R Guckes
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Taylor A Yount
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Caroline H Steingard
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Tim I Miyashiro
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA; The One Health Microbiome Center, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA.
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2
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Yount TA, Murtha AN, Cecere AG, Miyashiro TI. Quorum sensing facilitates interpopulation signaling by Vibrio fischeri within the light organ of Euprymna scolopes. Isr J Chem 2023; 63:e202200061. [PMID: 38524670 PMCID: PMC10959291 DOI: 10.1002/ijch.202200061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Indexed: 11/06/2022]
Abstract
Quorum sensing is an intercellular signaling mechanism that enables bacterial cells to coordinate population-level behaviors. How quorum sensing functions in natural habitats remains poorly understood. Vibrio fischeri is a bacterial symbiont of the Hawaiian bobtail squid Euprymna scolopes and depends on LuxI/LuxR quorum sensing to produce the symbiotic trait of bioluminescence. A previous study demonstrated that animals emit light when co-colonized by a Δlux mutant, which lacks several genes within the lux operon that are necessary for bioluminescence production, and a LuxI- mutant, which cannot synthesize the quorum signaling molecule N-3-oxohexanoyl-homoserine lactone. Here, we build upon that observation and show that populations of LuxI- feature elevated promoter activity for the lux operon. We find that population structures comprising of Δlux and LuxI- are attenuated within the squid, but a wild-type strain enables the LuxI- strain type to be maintained in vivo. These experimental results support a model of interpopulation signaling, which provides basic insight into how quorum sensing functions within the natural habitats found within a host.
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Affiliation(s)
| | | | - Andrew G. Cecere
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA
| | - Tim I. Miyashiro
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA
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3
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A lasting symbiosis: how Vibrio fischeri finds a squid partner and persists within its natural host. Nat Rev Microbiol 2021; 19:654-665. [PMID: 34089008 DOI: 10.1038/s41579-021-00557-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2021] [Indexed: 01/10/2023]
Abstract
As our understanding of the human microbiome progresses, so does the need for natural experimental animal models that promote a mechanistic understanding of beneficial microorganism-host interactions. Years of research into the exclusive symbiosis between the Hawaiian bobtail squid, Euprymna scolopes, and the bioluminescent bacterium Vibrio fischeri have permitted a detailed understanding of those bacterial genes underlying signal exchange and rhythmic activities that result in a persistent, beneficial association, as well as glimpses into the evolution of symbiotic competence. Migrating from the ambient seawater to regions deep inside the light-emitting organ of the squid, V. fischeri experiences, recognizes and adjusts to the changing environmental conditions. Here, we review key advances over the past 15 years that are deepening our understanding of these events.
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4
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Ziegler EW, Brown AB, Nesnas N, Chouinard CD, Mehta AK, Palmer AG. β-Cyclodextrin Encapsulation of Synthetic AHLs: Drug Delivery Implications and Quorum-Quenching Exploits. Chembiochem 2020; 22:1292-1301. [PMID: 33238068 DOI: 10.1002/cbic.202000773] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 11/23/2020] [Indexed: 12/22/2022]
Abstract
Many bacteria, such as Pseudomonas aeruginosa, regulate phenotypic switching in a population density-dependent manner through a phenomenon known as quorum sensing (QS). For Gram-negative bacteria, QS relies on the synthesis, transmission, and perception of low-molecular-weight signal molecules that are predominantly N-acyl-l-homoserine lactones (AHLs). Efforts to disrupt AHL-mediated QS have largely focused on the development of synthetic AHL analogues (SAHLAs) that are structurally similar to native AHLs. However, like AHLs, these molecules tend to be hydrophobic and are poorly soluble under aqueous conditions. Water-soluble macrocycles, such as cyclodextrins (CDs), that encapsulate hydrophobic guests have long been used by both the agricultural and pharmaceutical industries to overcome the solubility issues associated with hydrophobic compounds of interest. Conveniently, CDs have also demonstrated anti-AHL-mediated QS effects. Here, using fluorescence spectroscopy, NMR spectrometry, and mass spectrometry, we evaluate the affinity of SAHLAs, as well as their hydrolysis products, for β-CD inclusion. We also evaluated the ability of these complexes to inhibit wild-type P. aeruginosa virulence in a Caenorhabditis elegans host infection study, for the first time. Our efforts confirm the potential of β-CDs for the improved delivery of SAHLAs at the host/microbial interface, expanding the utility of this approach as a strategy for probing and controlling QS.
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Affiliation(s)
- Eric W Ziegler
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, 150W. University Boulevard, Melbourne, FL 32901, USA
| | - Alan B Brown
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, 150W. University Boulevard, Melbourne, FL 32901, USA
| | - Nasri Nesnas
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, 150W. University Boulevard, Melbourne, FL 32901, USA
| | - Christopher D Chouinard
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, 150W. University Boulevard, Melbourne, FL 32901, USA
| | - Anil K Mehta
- National High Magnetic Field Laboratory, McKnight Brain Institute, University of Florida, 1149 Newell Drive, Gainesville, FL 32610, USA
| | - Andrew G Palmer
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, 150W. University Boulevard, Melbourne, FL 32901, USA.,Department of Ocean Engineering and Marine Sciences, Florida Institute of Technology, 150W. University Boulevard, Melbourne, FL 32901, USA
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5
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Folcik AM, Cutshaw K, Haire T, Goode J, Shah P, Zaidi F, Richardson B, Palmer A. Quorum Sensing Behavior in the Model Unicellular Eukaryote Chlamydomonas reinhardtii. iScience 2020; 23:101714. [PMID: 33196031 PMCID: PMC7644740 DOI: 10.1016/j.isci.2020.101714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/25/2020] [Accepted: 10/16/2020] [Indexed: 10/25/2022] Open
Abstract
Microbial communities display behavioral changes in response to variable environmental conditions. In some bacteria, motility increases as a function of cell density, allowing for population dispersal before the onset of nutrient scarcity. Utilizing automated particle tracking, we now report on a population-dependent increase in the swimming speeds of the photosynthetic unicellular eukaryotes Chlamydomonas reinhardtii and C. moewussi. Our findings confirm that this acceleration in swimming speed arises as a function of culture density, rather than with age and/or nutrient availability. Furthermore, this phenomenon depends on the synthesis and detection of a low-molecular-weight compound which can be transferred between cultures and stimulates comparable effects across both species, supporting the existence of a conserved phenomenon, not unlike bacterial quorum sensing, among members of this genus. The potential expansion of density-dependent phenomena to a new group of unicellular eukaryotes provides important insight into how microbial populations evolve and regulate "social" behaviors.
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Affiliation(s)
- Alexandra M Folcik
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, USA
| | - Kirstin Cutshaw
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, USA
| | - Timothy Haire
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, USA
| | - Joseph Goode
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, USA
| | - Pooja Shah
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, USA
| | - Faizan Zaidi
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, USA
| | - Brianna Richardson
- Department of Aerospace, Physics, and Space Sciences, Florida Institute of Technology, Melbourne, FL, USA
| | - Andrew Palmer
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, USA.,Department of Ocean Engineering and Marine Sciences, Florida Institute of Technology, Melbourne, FL, USA.,Aldrin Space Institute, Florida Institute of Technology, Melbourne, FL, USA
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Wasilko NP, Larios-Valencia J, Steingard CH, Nunez BM, Verma SC, Miyashiro T. Sulfur availability for Vibrio fischeri growth during symbiosis establishment depends on biogeography within the squid light organ. Mol Microbiol 2019; 111:621-636. [PMID: 30506600 DOI: 10.1111/mmi.14177] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2018] [Indexed: 12/23/2022]
Abstract
The fitness of host-associated microbes depends on their ability to access nutrients in vivo. Identifying these mechanisms is significant for understanding how microbes have evolved to fill specific ecological niches within a host. Vibrio fischeri is a bioluminescent bacterium that colonizes and proliferates within the light organ of the Hawaiian bobtail squid, which provides an opportunity to study how bacteria grow in vivo. Here, the transcription factor CysB is shown to be necessary for V. fischeri both to grow on several sulfur sources in vitro and to establish symbiosis with juvenile squid. CysB is also found to regulate several genes involved in sulfate assimilation and to contribute to the growth of V. fischeri on cystine, which is the oxidized form of cysteine. A mutant that grows on cystine but not sulfate could establish symbiosis, suggesting that V. fischeri acquires nutrients related to this compound within the host. Finally, CysB-regulated genes are shown to be differentially expressed among the V. fischeri populations occupying the various colonization sites found within the light organ. Together, these results suggest the biogeography of V. fischeri populations within the squid light organ impacts the physiology of this symbiotic bacterium in vivo through CysB-dependent gene regulation.
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Affiliation(s)
- Nathan P Wasilko
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, 410 South Frear Laboratory, University Park, PA, 16802, USA
| | - Jessie Larios-Valencia
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, 410 South Frear Laboratory, University Park, PA, 16802, USA
| | - Caroline H Steingard
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, 410 South Frear Laboratory, University Park, PA, 16802, USA
| | - Briana M Nunez
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, 410 South Frear Laboratory, University Park, PA, 16802, USA
| | - Subhash C Verma
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, 410 South Frear Laboratory, University Park, PA, 16802, USA
| | - Tim Miyashiro
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, 410 South Frear Laboratory, University Park, PA, 16802, USA
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Palmer AG, Senechal AC, Haire TC, Mehta NP, Valiquette SD, Blackwell HE. Selection of Appropriate Autoinducer Analogues for the Modulation of Quorum Sensing at the Host-Bacterium Interface. ACS Chem Biol 2018; 13:3115-3122. [PMID: 30296049 PMCID: PMC6239973 DOI: 10.1021/acschembio.8b00676] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bacteria regulate a variety of phenotypes in response to their population density using quorum sensing (QS). This phenomenon is regulated by small molecule or peptide signals, the best characterized of which are the N-acyl l-homoserine lactones (AHLs) utilized by Gram-negative bacteria. As many QS-controlled phenotypes, notably pathogenicity and symbiosis, can profoundly impact host eukaryotes, there is significant interest in developing methods for modulating QS signaling and either ameliorating or augmenting these phenotypes. One strategy has been the use of non-native AHL analogues to agonize or antagonize specific AHL receptors. This approach is complicated, however, by the potential for prospective hosts to respond to both native AHLs and synthetic analogues. Accordingly, identifying AHL analogues with little or no activity toward eukaryotes is important in developing QS modulation as a strategy for the regulation of prokaryotic behaviors. Herein, we utilize the model plant Arabidopsis thaliana to characterize eukaryotic responses to a variety of synthetic AHL analogues to identify structural elements of existing scaffolds that may elicit responses in prospective hosts. Our results indicate that, while many of these compounds have no discernible effect on A. thaliana, some elicit strong phenotypes similar to those produced by auxin, a hormone involved in almost all aspects of plant development. We outline concentrations and chemical scaffolds that are ideal for deployment on plant hosts for the regulation of QS. This approach should be exportable to other eukaryotes for the selection of optimal AHL tools for the study of QS at the host-microbe interface.
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Affiliation(s)
- Andrew G. Palmer
- Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, 150 West University Blvd., Melbourne, FL 32901
| | - Amanda C. Senechal
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706
| | - Timothy C. Haire
- Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, 150 West University Blvd., Melbourne, FL 32901
| | - Nidhi P. Mehta
- Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, 150 West University Blvd., Melbourne, FL 32901
| | - Sara D. Valiquette
- Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, 150 West University Blvd., Melbourne, FL 32901
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706
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Byndloss MX, Pernitzsch SR, Bäumler AJ. Healthy hosts rule within: ecological forces shaping the gut microbiota. Mucosal Immunol 2018; 11:1299-1305. [PMID: 29743614 DOI: 10.1038/s41385-018-0010-y] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 01/05/2018] [Indexed: 02/04/2023]
Abstract
A balanced gut microbiota is important for human health, but the mechanisms that maintain homeostasis are incompletely understood. Recent insights suggest the host plays a key role in shaping its gut microbiota to be beneficial. While host control in the small intestine curbs bacterial numbers to avoid competition for simple sugars and amino acids, the host limits oxygen availability in the large intestine to obtain microbial fermentation products from fiber. Epithelial cells are major players in imposing ecological control mechanisms, which involves the release of antimicrobial peptides by small-intestinal Paneth cells and maintenance of luminal anaerobiosis by epithelial hypoxia in the colon. Harnessing these epithelial control mechanisms for therapeutic means could provide a novel lynchpin for strategies to remediate dysbiosis.
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Affiliation(s)
- Mariana X Byndloss
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA, 95616, USA
| | | | - Andreas J Bäumler
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA, 95616, USA.
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Plakunov VK, Mart’yanov SV, Teteneva NA, Zhurina MV. Controlling of microbial biofilms formation: Anti- and probiofilm agents. Microbiology (Reading) 2017. [DOI: 10.1134/s0026261717040129] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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10
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Schwartzman JA, Ruby EG. A conserved chemical dialog of mutualism: lessons from squid and vibrio. Microbes Infect 2016; 18:1-10. [PMID: 26384815 PMCID: PMC4715918 DOI: 10.1016/j.micinf.2015.08.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 08/28/2015] [Accepted: 08/31/2015] [Indexed: 12/18/2022]
Abstract
Microorganisms shape, and are shaped by, their environment. In host-microbe associations, this environment is defined by tissue chemistry, which reflects local and organism-wide physiology, as well as inflammatory status. We review how, in the squid-vibrio mutualism, both partners shape tissue chemistry, revealing common themes governing tissue homeostasis in animal-microbe associations.
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Affiliation(s)
- Julia A Schwartzman
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Madison, WI 53706, USA
| | - Edward G Ruby
- Kewalo Marine Laboratory, University of Hawaii, Manoa, Honolulu, HI 96813, USA.
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A Single Host-Derived Glycan Impacts Key Regulatory Nodes of Symbiont Metabolism in a Coevolved Mutualism. mBio 2015; 6:e00811. [PMID: 26173698 PMCID: PMC4502230 DOI: 10.1128/mbio.00811-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Most animal-microbe mutualistic associations are characterized by nutrient exchange between the partners. When the host provides the nutrients, it can gain the capacity to shape its microbial community, control the stability of the interaction, and promote its health and fitness. Using the bioluminescent squid-vibrio model, we demonstrate how a single host-derived glycan, chitin, regulates the metabolism of Vibrio fischeri at key points in the development and maintenance of the symbiosis. We first characterized the pathways for catabolism of chitin sugars by V. fischeri, demonstrating that the Ccr-dependent phosphoenolpyruvate-pyruvate phosphotransferase system (PTS) prioritizes transport of these sugars in V. fischeri by blocking the uptake of non-PTS carbohydrates, such as glycerol. Next, we found that PTS transport of chitin sugars into the bacterium shifted acetate homeostasis toward a net excretion of acetate and was sufficient to override an activation of the acetate switch by AinS-dependent quorum sensing. Finally, we showed that catabolism of chitin sugars decreases the rate of cell-specific oxygen consumption. Collectively, these three metabolic functions define a physiological shift that favors fermentative growth on chitin sugars and may support optimal symbiont luminescence, the functional basis of the squid-vibrio mutualism. Host-derived glycans have recently emerged as a link between symbiont nutrition and innate immune function. Unfortunately, the locations at which microbes typically access host-derived glycans are inaccessible to experimentation and imaging, and they take place in the context of diverse microbe-microbe interactions, creating a complex symbiotic ecology. Here we describe the metabolic state of a single microbial symbiont in a natural association with its coevolved host and, by doing so, infer key points at which a host-controlled tissue environment might regulate the physiological state of its symbionts. We show that the presence of a regulatory glycan is sufficient to shift symbiont carbohydrate catabolism, acetate homeostasis, and oxygen consumption.
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