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Zhao X, Li X, Gao J, Shen S, Zou W. Behavioral adaptations of Caenorhabditis elegans against pathogenic threats. PeerJ 2025; 13:e19294. [PMID: 40247835 PMCID: PMC12005179 DOI: 10.7717/peerj.19294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2025] [Accepted: 03/19/2025] [Indexed: 04/19/2025] Open
Abstract
This review examines the behavioral adaptation mechanisms of Caenorhabditis elegans in response to pathogenic bacterial threats, emphasizing their ecological significance. It systematically explores how mechanisms such as avoidance behavior, transgenerational learning, and forgetting enable C. elegans to optimize its survival and reproductive strategies within dynamic microbial environments. C. elegans detects harmful signals through chemosensation and initiates avoidance behaviors. Simultaneously, it manages environmental adaptation and energy allocation through transgenerational memory and forgetting, allowing C. elegans to cope with selective pressures from environmental fluctuations. In contrast, pathogenic bacteria such as Pseudomonas aeruginosa and Salmonella influence C. elegans behavior through strategies such as toxin release and biofilm formation, highlighting the complex co-evolutionary dynamics between hosts and pathogens. Additionally, these pathogens employ "Trojan Horse-like" and "Worm Star" mechanisms to kill C. elegans, further complicating host-pathogen interactions. These processes are driven by behavioral adaptations, biochemical signaling, and evolutionary pressures, which emphasize the ecological niche of C. elegans within microbial ecosystems. C. elegans serves as a valuable model for studying host-pathogen interactions. This study provides crucial theoretical insights into adaptive evolution and ecosystem dynamics, offering valuable guidance for the development of biocontrol strategies and the effective management of microbial ecosystems.
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Affiliation(s)
- Xin Zhao
- Kunming Medical University, School of Public Health, Kunming, Yunnan, China
- Xi’an Public Health Center, Infection Control Office, Xi’an, Shaanxi, China
| | - Xinyu Li
- Kunming Medical University, School of Public Health, Kunming, Yunnan, China
| | - Jiayi Gao
- Xi’an Public Health Center, Infection Control Office, Xi’an, Shaanxi, China
| | - Shi Shen
- Xi’an Public Health Center, Infection Control Office, Xi’an, Shaanxi, China
| | - Wei Zou
- Kunming Medical University, School of Public Health, Kunming, Yunnan, China
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2
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Hodgkin J, Stroud D, O'Rourke D. Mutations of nhr-49 affect C. elegans susceptibility to Yersinia biofilms. MICROPUBLICATION BIOLOGY 2025; 2025:10.17912/micropub.biology.001522. [PMID: 39975509 PMCID: PMC11836678 DOI: 10.17912/micropub.biology.001522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2025] [Revised: 02/03/2025] [Accepted: 02/03/2025] [Indexed: 02/21/2025]
Abstract
The C. elegans transcription factor NHR-49 has been extensively studied for its functions in regulating metabolic processes, stress responses, innate immunity and aging. Molecular identification of a gene previously known as bah-3 , which affects susceptibility of worms to deleterious surface attachment of bacterial biofilms from Yersinia spp., revealed that bah-3 ( dc9 ) is an ochre nonsense allele of nhr-49 . Other severe mutations of nhr-49 also had a Bah phenotype, but deletions affecting 5' isoforms of the gene did not affect biofilm attachment, nor did 3' gain-of-function missense mutations. Other bah genes ( bah-1 , bah-2 , bah-4 ) encode GT92 glycosylation factors, predicted to affect surface coat. NHR-49 may act as a positive transcription factor for one or more of these surface glycosylation genes, in contrast to its other roles in regulating metabolic processes.
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Affiliation(s)
- Jonathan Hodgkin
- Biochemistry, University of Oxford, Oxford, England, United Kingdom
| | - Dave Stroud
- Biochemistry, University of Oxford, Oxford, England, United Kingdom
| | - Delia O'Rourke
- Centre for Human Genetics, University of Oxford, Oxford, England, United Kingdom
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3
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Li J, Smith CA, Chen J, Bates KA, King KC. Warming During Different Life Stages has Distinct Impacts on Host Resistance Ecology and Evolution. Ecol Lett 2025; 28:e70087. [PMID: 39981937 PMCID: PMC11843851 DOI: 10.1111/ele.70087] [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: 07/17/2024] [Revised: 01/08/2025] [Accepted: 02/01/2025] [Indexed: 02/22/2025]
Abstract
Climate change is increasing extreme heating events and the potential for disease outbreaks. Whether hosts can adapt to infection with rising temperatures is important for forecasting species persistence. We tested whether warming-at different host life stages-affects the ecological and evolutionary dynamics of resistance in Caenorhabditis elegans infected by a wild bacterial pathogen. We competed resistant and susceptible genotypes across 10 passages and tracked the spread of resistance in the population. Infection and prolonged warming strongly selected for the resistant genotype. Warming during host development induced plastic defences against infection, reducing the selective pressure for costly genetic-based resistance. Resistance was lost under ambient temperatures and periodic warming. Selection for resistance was likely weakened at ambient temperatures by the dilution effect, whereby the resistant genotype reduced pathogen transmission. Evolutionary dynamics of resistance depend on the balance among pathogen virulence, costs of genetic-based resistance, the dilution effect and plastic defences induced by temperature stress.
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Affiliation(s)
- Jingdi Li
- Department of BiologyUniversity of OxfordOxfordUK
- Department of ZoologyUniversity of British ColumbiaVancouverCanada
| | | | - Jinlin Chen
- Department of BiologyUniversity of OxfordOxfordUK
| | - Kieran A. Bates
- Blizard Institute, Faculty of Medicine and DentistryQueen Mary University of LondonLondonUK
| | - Kayla C. King
- Department of BiologyUniversity of OxfordOxfordUK
- Department of ZoologyUniversity of British ColumbiaVancouverCanada
- Department of Microbiology & ImmunologyUniversity of British ColumbiaVancouverCanada
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4
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Holt CC, del Campo J, Keeling PJ. Source and variation of the amazing live Sea-Monkey microbiome. PLoS One 2024; 19:e0308763. [PMID: 39133745 PMCID: PMC11318892 DOI: 10.1371/journal.pone.0308763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Accepted: 07/30/2024] [Indexed: 08/15/2024] Open
Abstract
An embryonic diapause in unfavourable conditions has allowed brine shrimp to thrive in hypersaline environments and, unexpectedly, mail-order sachets and small, novelty tanks. Marketed as Sea-Monkeys®, each kit involves a 3-step process to generate adult Artemia within a matter of weeks. Whether these kits also allow for the maintenance of a host-associated microbiome is unclear. Therefore, comparing five replicate tanks under the same culture conditions, we sequenced the 16S ribosomal small subunit (SSU) gene to analyse bacterial community compositions in adults, their surrounding tank water, and their feed. Adult Sea-Monkeys® harboured a bacterial microbiome that was clearly distinguishable from the tank water and food. Furthermore, individual tanks had a notable effect on fine-scale microbiome variation. Several Sea-Monkey bacterial variants appeared absent in environmental samples and included genera (Leucobacter and Microbacterium) known to confer desiccation resistance in other hosts. Although Sea-Monkeys® taxonomy is unclear, phylogenetic inference of the cytochrome c oxidase I (COXI) gene from the host animal suggests Sea-Monkeys® belong to the Artemia franciscana 'superspecies'. Overall, Sea-Monkeys® kits appear to be a convenient and scalable mesocosm for the study of host-microbiome interactions and could serve as a useful tool for future invertebrate microbiome research, outreach, and education.
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Affiliation(s)
- Corey C. Holt
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
- Hakai Institute, Heriot Bay, British Columbia, Canada
| | - Javier del Campo
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Catalonia, Spain
| | - Patrick J. Keeling
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
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Sundaram MV, Pujol N. The Caenorhabditis elegans cuticle and precuticle: a model for studying dynamic apical extracellular matrices in vivo. Genetics 2024; 227:iyae072. [PMID: 38995735 PMCID: PMC11304992 DOI: 10.1093/genetics/iyae072] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 03/25/2024] [Indexed: 07/14/2024] Open
Abstract
Apical extracellular matrices (aECMs) coat the exposed surfaces of animal bodies to shape tissues, influence social interactions, and protect against pathogens and other environmental challenges. In the nematode Caenorhabditis elegans, collagenous cuticle and zona pellucida protein-rich precuticle aECMs alternately coat external epithelia across the molt cycle and play many important roles in the worm's development, behavior, and physiology. Both these types of aECMs contain many matrix proteins related to those in vertebrates, as well as some that are nematode-specific. Extensive differences observed among tissues and life stages demonstrate that aECMs are a major feature of epithelial cell identity. In addition to forming discrete layers, some cuticle components assemble into complex substructures such as ridges, furrows, and nanoscale pillars. The epidermis and cuticle are mechanically linked, allowing the epidermis to sense cuticle damage and induce protective innate immune and stress responses. The C. elegans model, with its optical transparency, facilitates the study of aECM cell biology and structure/function relationships and all the myriad ways by which aECM can influence an organism.
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Affiliation(s)
- Meera V Sundaram
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Nathalie Pujol
- Aix Marseille University, INSERM, CNRS, CIML, Turing Centre for Living Systems, 13009 Marseille, France
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6
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Haghani NB, Lampe RH, Samuel BS, Chalasani SH, Matty MA. Identification and characterization of a skin microbiome on Caenorhabditis elegans suggests environmental microbes confer cuticle protection. Microbiol Spectr 2024; 12:e0016924. [PMID: 38980017 PMCID: PMC11302229 DOI: 10.1128/spectrum.00169-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 06/10/2024] [Indexed: 07/10/2024] Open
Abstract
In the wild, C. elegans are emersed in environments teeming with a veritable menagerie of microorganisms. The C. elegans cuticular surface serves as a barrier and first point of contact with their microbial environments. In this study, we identify microbes from C. elegans natural habitats that associate with its cuticle, constituting a simple "skin microbiome." We rear our animals on a modified CeMbio, mCeMbio, a consortium of ecologically relevant microbes. We first combine standard microbiological methods with an adapted micro skin-swabbing tool to describe the skin-resident bacteria on the C. elegans surface. Furthermore, we conduct 16S rRNA gene sequencing studies to identify relative shifts in the proportion of mCeMbio bacteria upon surface-sterilization, implying distinct skin- and gut-microbiomes. We find that some strains of bacteria, including Enterobacter sp. JUb101, are primarily found on the nematode skin, while others like Stenotrophomonas indicatrix JUb19 and Ochrobactrum vermis MYb71 are predominantly found in the animal's gut. Finally, we show that this skin microbiome promotes host cuticle integrity in harsh environments. Together, we identify a skin microbiome for the well-studied nematode model and propose its value in conferring host fitness advantages in naturalized contexts. IMPORTANCE The genetic model organism C. elegans has recently emerged as a tool for understanding host-microbiome interactions. Nearly all of these studies either focus on pathogenic or gut-resident microbes. Little is known about the existence of native, nonpathogenic skin microbes or their function. We demonstrate that members of a modified C. elegans model microbiome, mCeMbio, can adhere to the animal's cuticle and confer protection from noxious environments. We combine a novel micro-swab tool, the first 16S microbial sequencing data from relatively unperturbed C. elegans, and physiological assays to demonstrate microbially mediated protection of the skin. This work serves as a foundation to explore wild C. elegans skin microbiomes and use C. elegans as a model for skin research.
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Affiliation(s)
- Nadia B. Haghani
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, California, USA
- University of California San Diego, La Jolla, California, USA
| | - Robert H. Lampe
- Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, California, USA
- Integrative Oceanography Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, USA
| | - Buck S. Samuel
- Alkek Center for Metagenomics and Microbiome Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
| | - Sreekanth H. Chalasani
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, California, USA
- University of California San Diego, La Jolla, California, USA
| | - Molly A. Matty
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, California, USA
- Biology, University of Portland, Portland, Oregon, USA
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Li JD, Gao YY, Stevens EJ, King KC. Dual stressors of infection and warming can destabilize host microbiomes. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230069. [PMID: 38497264 PMCID: PMC10945407 DOI: 10.1098/rstb.2023.0069] [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: 08/10/2023] [Accepted: 01/02/2024] [Indexed: 03/19/2024] Open
Abstract
Climate change is causing extreme heating events and intensifying infectious disease outbreaks. Animals harbour microbial communities, which are vital for their survival and fitness under stressful conditions. Understanding how microbiome structures change in response to infection and warming may be important for forecasting host performance under global change. Here, we evaluated alterations in the microbiomes of several wild Caenorhabditis elegans isolates spanning a range of latitudes, upon warming temperatures and infection by the parasite Leucobacter musarum. Using 16S rRNA sequencing, we found that microbiome diversity decreased, and dispersion increased over time, with the former being more prominent in uninfected adults and the latter aggravated by infection. Infection reduced dominance of specific microbial taxa, and increased microbiome dispersion, indicating destabilizing effects on host microbial communities. Exposing infected hosts to warming did not have an additive destabilizing effect on their microbiomes. Moreover, warming during pre-adult development alleviated the destabilizing effects of infection on host microbiomes. These results revealed an opposing interaction between biotic and abiotic factors on microbiome structure. Lastly, we showed that increased microbiome dispersion might be associated with decreased variability in microbial species interaction strength. Overall, these findings improve our understanding of animal microbiome dynamics amidst concurrent climate change and epidemics. This article is part of the theme issue 'Sculpting the microbiome: how host factors determine and respond to microbial colonization'.
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Affiliation(s)
- J. D. Li
- Department of Biology, University of Oxford, Oxford OX1 2JD, UK
| | - Y. Y. Gao
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, People's Republic of China
- School of Ecology and Nature Conservation, Beijing Forestry University, 35 Tsinghua East Road, Beijing 100083, People's Republic of China
| | - E. J. Stevens
- Department of Biology, University of Oxford, Oxford OX1 2JD, UK
| | - K. C. King
- Department of Biology, University of Oxford, Oxford OX1 2JD, UK
- Department of Zoology, University of British Columbia, Vancouver, V6T 1Z4, Canada
- Department of Microbiology & Immunology, University of British Columbia, Vancouver, V6T 1Z3, Canada
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8
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Drury F, Grover M, Hintze M, Saunders J, Fasseas MK, Constantinou C, Barkoulas M. A PAX6-regulated receptor tyrosine kinase pairs with a pseudokinase to activate immune defense upon oomycete recognition in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2023; 120:e2300587120. [PMID: 37725647 PMCID: PMC10523662 DOI: 10.1073/pnas.2300587120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 08/21/2023] [Indexed: 09/21/2023] Open
Abstract
Oomycetes were recently discovered as natural pathogens of Caenorhabditis elegans, and pathogen recognition alone was shown to be sufficient to activate a protective transcriptional program characterized by the expression of multiple chitinase-like (chil) genes. However, the molecular mechanisms underlying oomycete recognition in animals remain fully unknown. We performed here a forward genetic screen to uncover regulators of chil gene induction and found several independent loss-of-function alleles of old-1 and flor-1, which encode receptor tyrosine kinases belonging to the C. elegans-specific KIN-16 family. We report that OLD-1 and FLOR-1 are both necessary for mounting the immune response and act in the epidermis. FLOR-1 is a pseudokinase that acts downstream of the active kinase OLD-1 and regulates OLD-1 levels at the plasma membrane. Interestingly, the old-1 locus is adjacent to the chil genes in the C. elegans genome, thereby revealing a genetic cluster important for oomycete resistance. Furthermore, we demonstrate that old-1 expression at the anterior side of the epidermis is regulated by the VAB-3/PAX6 transcription factor, well known for its role in visual system development in other animals. Taken together, our study reveals both conserved and species-specific factors shaping the activation and spatial characteristics of the immune response to oomycete recognition.
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Affiliation(s)
- Florence Drury
- Department of Life Sciences, Imperial College, LondonSW7 2AZ, United Kingdom
| | - Manish Grover
- Department of Life Sciences, Imperial College, LondonSW7 2AZ, United Kingdom
| | - Mark Hintze
- Department of Life Sciences, Imperial College, LondonSW7 2AZ, United Kingdom
| | - Jonathan Saunders
- Department of Life Sciences, Imperial College, LondonSW7 2AZ, United Kingdom
| | - Michael K. Fasseas
- Department of Life Sciences, Imperial College, LondonSW7 2AZ, United Kingdom
| | - Charis Constantinou
- Department of Life Sciences, Imperial College, LondonSW7 2AZ, United Kingdom
| | - Michalis Barkoulas
- Department of Life Sciences, Imperial College, LondonSW7 2AZ, United Kingdom
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O’Rourke D, Gravato-Nobre MJ, Stroud D, Pritchett E, Barker E, Price RL, Robinson SA, Spiro S, Kuwabara P, Hodgkin J. Isolation and molecular identification of nematode surface mutants with resistance to bacterial pathogens. G3 (BETHESDA, MD.) 2023; 13:jkad056. [PMID: 36911920 PMCID: PMC10151413 DOI: 10.1093/g3journal/jkad056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 02/16/2023] [Accepted: 02/22/2023] [Indexed: 03/14/2023]
Abstract
Numerous mutants of the nematode Caenorhabditis elegans with surface abnormalities have been isolated by utilizing their resistance to a variety of bacterial pathogens (Microbacterium nematophilum, Yersinia pseudotuberculosis, and 2 Leucobacter strains), all of which are able to cause disease or death when worms are grown on bacterial lawns containing these pathogens. Previous work led to the identification of 9 srf or bus genes; here, we report molecular identification and characterization of a further 10 surface-affecting genes. Three of these were found to encode factors implicated in glycosylation (srf-2, bus-5, and bus-22), like several of those previously reported; srf-2 belongs to the GT92 family of putative galactosyltransferases, and bus-5 is homologous to human dTDP-D-glucose 4,6-dehydratase, which is implicated in Catel-Manzke syndrome. Other genes encoded proteins with sequence similarity to phosphatidylinositol phosphatases (bus-6), Patched-related receptors (ptr-15/bus-13), steroid dehydrogenases (dhs-5/bus-21), or glypiation factors (bus-24). Three genes appeared to be nematode-specific (srf-5, bus-10, and bus-28). Many mutants exhibited cuticle fragility as revealed by bleach and detergent sensitivity; this fragility was correlated with increased drug sensitivity, as well as with abnormal skiddy locomotion. Most of the genes examined were found to be expressed in epidermal seam cells, which appear to be important for synthesizing nematode surface coat. The results reveal the genetic and biochemical complexity of this critical surface layer, and provide new tools for its analysis.
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Affiliation(s)
- Delia O’Rourke
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | | | - Dave Stroud
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Emily Pritchett
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Emily Barker
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Rebecca L Price
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Sarah A Robinson
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Simon Spiro
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | | | - Jonathan Hodgkin
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
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10
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Zhang H, Yu Y, Li J, Gong P, Wang X, Li X, Cheng Y, Yu X, Zhang N, Zhang X. Changes of gut microbiota in colorectal cancer patients with Pentatrichomonas hominis infection. Front Cell Infect Microbiol 2022; 12:961974. [PMID: 36118043 PMCID: PMC9471007 DOI: 10.3389/fcimb.2022.961974] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 07/27/2022] [Indexed: 01/11/2023] Open
Abstract
Pentatrichomonas hominis is a parasitic trichomonads protozoa that parasitizes in the colon and cecum of humans and other animals. Our previous studies have demonstrated that infection with P. hominis is associated with the incidence of colon cancer (37.93%). However, the mechanism by which P. hominis infections increase the incidence of colon cancer remains unclear. Previous studies have suggested that certain parasites promote colon cancer by regulating gut microbiota. This study aimed to elucidate whether the association between P. hominis infections and the increased incidence of colon cancer is related to changes in gut microbiota. Therefore, the gut microbiota patients with colon cancer who were infected with P. hominis and uninfected patients with colon cancer were analyzed by 16S rRNA high-throughput sequencing. The results demonstrated that patients with colon cancer who were not infected with P. hominis showed increased gut bacterial diversity, a higher relative abundance of Alcaligenes sp., Leucobacter sp., Paraprevotella sp., Ruminococcaceae UCG-002, and a significant reduction in the abundance of Veillonella sp., compared to individuals without colon cancer. Additionally, the relative abundance of the Ruminococcaceae UCG-002 and the Eubacterium eligens groups was reduced, while the relative abundance of bacteria associated with colon cancer, including Flavonifractor sp., Lachnoclostridium sp., and the Ruminococcus gnavus group, increased significantly in patients with colon cancer who were infected with P. hominis, compared to those of uninfected patients with colon cancer. In conclusion, these results suggested that P. hominis infections may aggravate the development of colon cancer and the findings provide new insights for subsequent in-depth studies on the pathogenesis, diagnosis, and prevention of colon cancer.
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Affiliation(s)
- Hongbo Zhang
- Key Laboratory of Zoonosis Research by Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Yanhui Yu
- Second Affiliated Hospital, Jilin University, Changchun, China
| | - Jianhua Li
- Key Laboratory of Zoonosis Research by Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Pengtao Gong
- Key Laboratory of Zoonosis Research by Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xiaocen Wang
- Key Laboratory of Zoonosis Research by Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xin Li
- Key Laboratory of Zoonosis Research by Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Yidan Cheng
- Key Laboratory of Zoonosis Research by Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xiuyan Yu
- Clinical Laboratory, Jilin Cancer Hospital, Changchun, China
| | - Nan Zhang
- Key Laboratory of Zoonosis Research by Ministry of Education, Institute of Zoonosis, Jilin University, Changchun, China
- *Correspondence: Nan Zhang, ; Xichen Zhang,
| | - Xichen Zhang
- Key Laboratory of Zoonosis Research by Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
- *Correspondence: Nan Zhang, ; Xichen Zhang,
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11
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De Dreu CKW, Triki Z. Intergroup conflict: origins, dynamics and consequences across taxa. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210134. [PMID: 35369751 PMCID: PMC8977662 DOI: 10.1098/rstb.2021.0134] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Although uniquely destructive and wasteful, intergroup conflict and warfare are not confined to humans. They are seen across a range of group-living species, from social insects, fishes and birds to mammals, including nonhuman primates. With its unique collection of theory, research and review contributions from biology, anthropology and economics, this theme issue provides novel insights into intergroup conflict across taxa. Here, we introduce and organize this theme issue on the origins and consequences of intergroup conflict. We provide a coherent framework by modelling intergroup conflicts as multi-level games of strategy in which individuals within groups cooperate to compete with (individuals in) other groups for scarce resources, such as territory, food, mating opportunities, power and influence. Within this framework, we identify cross-species mechanisms and consequences of (participating in) intergroup conflict. We conclude by highlighting crosscutting innovations in the study of intergroup conflict set forth by individual contributions. These include, among others, insights on how within-group heterogeneities and leadership relate to group conflict, how intergroup conflict shapes social organization and how climate change and environmental degradation transition intergroup relations from peaceful coexistence to violent conflict. This article is part of the theme issue ‘Intergroup conflict across taxa’.
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Affiliation(s)
- Carsten K W De Dreu
- Institute of Psychology, Leiden University, Leiden, The Netherlands.,Center for Research in Experimental Economics and Political Decision Making, University of Amsterdam, Amsterdam, The Netherlands
| | - Zegni Triki
- Department of Zoology, Stockholm University, Stockholm, Sweden
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12
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de Oliveira Sant’Anna L, Cappelli EA, Batista Araújo MR, Ramos JN, Simpson-Lourêdo L, Cucinelli ADES, Pereira Baio PV, Vieira VV, Sanches dos Santos L, Mattos-Guaraldi AL. Virulence potential of the first Corynebacterium mycetoides strain isolated from human urine: a rare species of Corynebacterium. Microbes Infect 2022; 24:105001. [DOI: 10.1016/j.micinf.2022.105001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 05/04/2022] [Accepted: 05/06/2022] [Indexed: 10/31/2022]
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13
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Rasmussen NR, Reiner DJ. Nuclear translocation of the tagged endogenous MAPK MPK-1 denotes a subset of activation events in C. elegans development. J Cell Sci 2021; 134:272044. [PMID: 34341823 PMCID: PMC8445601 DOI: 10.1242/jcs.258456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 07/14/2021] [Indexed: 11/20/2022] Open
Abstract
The extracellular signal-regulated kinases (ERKs) are mitogen-activated protein kinases (MAPKs) that are utilized downstream of Ras to Raf to MEK signaling to control activation of a wide array of targets. Activation of ERKs is elevated in Ras-driven tumors and RASopathies, and thus is a target for pharmacological inhibition. Regulatory mechanisms of ERK activation have been studied extensively in vitro and in cultured cells, but little in living animals. In this study, we tagged the Caenorhabditis elegans ERK-encoding gene, mpk-1. MPK-1 is ubiquitously expressed with elevated expression in certain contexts. We detected cytosol-to-nuclear translocation of MPK-1 in maturing oocytes and hence validated nuclear translocation as a reporter of some activation events. During patterning of vulval precursor cells (VPCs), MPK-1 is necessary and sufficient for the central cell, P6.p, to assume the primary fate. Yet MPK-1 translocates to the nuclei of all six VPCs in a temporal and concentration gradient centered on P6.p. This observation contrasts with previous results using the ERK nuclear kinase translocation reporter of substrate activation, raising questions about mechanisms and indicators of MPK-1 activation. This system and reagent promise to provide critical insights into the regulation of MPK-1 activation within a complex intercellular signaling network. Summary: Tagged endogenous C. elegans MPK-1 shows activation-dependent cytosol-to-nuclear translocation. This tool provides novel insights into MPK-1 localization compared with other markers of in vivo ERK activation.
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Affiliation(s)
- Neal R Rasmussen
- Institute of Biosciences and Technology, College of Medicine, Texas A&M Health Science Center, Texas A&M University, Houston, 77030, USA
| | - David J Reiner
- Institute of Biosciences and Technology, College of Medicine, Texas A&M Health Science Center, Texas A&M University, Houston, 77030, USA
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14
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Tancos MA, McMahon MB, Garrett WM, Luster DG, Rogers EE. Comparative Secretome Analyses of Toxigenic and Atoxigenic Rathayibacter Species. PHYTOPATHOLOGY 2021; 111:1530-1540. [PMID: 33499664 DOI: 10.1094/phyto-11-20-0495-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Phytopathogenic Rathayibacter species are unique bacterial plant pathogens because they are obligately vectored by plant parasitic anguinid nematodes to the developing seedheads of forage grasses and cereals. This understudied group of plant-associated Actinomycetes includes the neurotoxigenic plant pathogen R. toxicus, which causes annual ryegrass toxicity in grazing livestock. R. toxicus is currently endemic to Australia and is listed as a plant pathogen select agent by the U.S. Department of Agriculture-Animal and Plant Health Inspection Service. The complex Rathayibacter disease cycle requires intimate interactions with the nematode vector and plant hosts, which warrants an increased understanding of the secretory and surface-associated proteins that mediate these diverse eukaryotic interactions. Here we present the first comparative secretome analysis for this complex, nematode-vectored Rathayibacter genus that compares the three agronomically damaging toxigenic and atoxigenic Rathayibacter species, R. toxicus, R. iranicus, and R. tritici. The exoproteomic comparison identified 1,423 unique proteins between the three species via liquid chromatography-tandem mass spectrometry, leading to the identification of putative pathogenicity-related proteins and proteins that may mediate nematode attachment. Of the uniquely identified proteins, 94 homologous proteins were conserved between the three Rathayibacter exoproteomes and comprised between 43.4 and 58.6% of total protein abundance. Comparative analyses revealed both conserved and uniquely expressed extracellular proteins, which, interestingly, had more similarities to extracellular proteins commonly associated with bacterial animal pathogens than classic plant pathogens. This comparative exoproteome analysis will facilitate the characterization of proteins essential for vector attachment and host colonization and assist in the development of serological diagnostic assays.
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Affiliation(s)
- Matthew A Tancos
- Foreign Disease-Weed Science Research Unit, U.S. Department of Agriculture-Agricultural Research Service, Frederick, MD
| | - Michael B McMahon
- Foreign Disease-Weed Science Research Unit, U.S. Department of Agriculture-Agricultural Research Service, Frederick, MD
| | - Wesley M Garrett
- Animal Biosciences and Biotechnology Laboratory, U.S. Department of Agriculture-Agricultural Research Service, Beltsville, MD
| | - Douglas G Luster
- Foreign Disease-Weed Science Research Unit, U.S. Department of Agriculture-Agricultural Research Service, Frederick, MD
| | - Elizabeth E Rogers
- Foreign Disease-Weed Science Research Unit, U.S. Department of Agriculture-Agricultural Research Service, Frederick, MD
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15
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Lažetić V, Troemel ER. Conservation lost: host-pathogen battles drive diversification and expansion of gene families. FEBS J 2021; 288:5289-5299. [PMID: 33190369 PMCID: PMC10901648 DOI: 10.1111/febs.15627] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/29/2020] [Accepted: 11/12/2020] [Indexed: 11/30/2022]
Abstract
One of the strongest drivers in evolution is the struggle to survive a host-pathogen battle. This pressure selects for diversity among the factors directly involved in this battle, including virulence factors deployed by pathogens, their corresponding host targets, and host immune factors. A logical outcome of this diversification is that over time, the sequence of many immune factors will not be evolutionarily conserved across a broad range of species. Thus, while universal sequence conservation is often hailed as the hallmark of the importance of a particular gene, the immune system does not necessarily play by these rules when defending against co-evolving pathogens. This loss of sequence conservation is in contrast to many signaling pathways in development and basic cell biology that are not targeted by pathogens. In addition to diversification, another consequence of host-pathogen battles can be an amplification in gene number, thus leading to large gene families that have sequence relatively specific to a particular strain, species, or clade. Here we highlight this general theme across a variety of pathogen virulence factors and host immune factors. We summarize the wide range and number across species of these expanded, lineage-specific host-pathogen factors including ubiquitin ligases, nucleotide-binding leucine-rich repeat receptors, GTPases, and proteins without obvious biochemical function but that nonetheless play key roles in immunity.
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Affiliation(s)
- Vladimir Lažetić
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Emily R Troemel
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
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16
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Bates KA, King KC. Leucobacter. Trends Microbiol 2021; 29:1046-1047. [PMID: 34304971 DOI: 10.1016/j.tim.2021.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/21/2021] [Accepted: 06/22/2021] [Indexed: 10/20/2022]
Affiliation(s)
- Kieran A Bates
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK.
| | - Kayla C King
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK
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17
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Bates KA, Bolton JS, King KC. A globally ubiquitous symbiont can drive experimental host evolution. Mol Ecol 2021; 30:3882-3892. [PMID: 34037279 DOI: 10.1111/mec.15998] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 01/04/2023]
Abstract
Organisms harbour myriad microbes which can be parasitic or protective against harm. The costs and benefits resulting from these symbiotic relationships can be context-dependent, but the evolutionary consequences to hosts of these transitions remain unclear. Here, we mapped the Leucobacter genus across 13,715 microbiome samples (163 studies) to reveal a global distribution as a free-living microbe or a symbiont of animals and plants. We showed that across geographically distant locations (South Africa, France, Cape Verde), Leucobacter isolates vary substantially in their virulence to an associated animal host, Caenorhabditis nematodes. We further found that multiple Leucobacter sequence variants co-occur in wild Caenorhabditis spp. which combined with natural variation in virulence provides real-world potential for Leucobacter community composition to influence host fitness. We examined this by competing C. elegans genotypes that differed in susceptibility to different Leucobacter species in an evolution experiment. One Leucobacter species was found to be host-protective against another, virulent parasitic species. We tested the impact of host genetic background and Leucobacter community composition on patterns of host-based defence evolution. We found host genotypes conferring defence against the parasitic species were maintained during infection. However, when hosts were protected during coinfection, host-based defences were nearly lost from the population. Overall, our results provide insight into the role of community context in shaping host evolution during symbioses.
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Affiliation(s)
| | - Jai S Bolton
- Department of Zoology, University of Oxford, Oxford, UK
| | - Kayla C King
- Department of Zoology, University of Oxford, Oxford, UK
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18
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Radeke LJ, Herman MA. Take a Walk to the Wild Side of Caenorhabditis elegans-Pathogen Interactions. Microbiol Mol Biol Rev 2021; 85:e00146-20. [PMID: 33731489 PMCID: PMC8139523 DOI: 10.1128/mmbr.00146-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Microbiomes form intimate functional associations with their hosts. Much has been learned from correlating changes in microbiome composition to host organismal functions. However, in-depth functional studies require the manipulation of microbiome composition coupled with the precise interrogation of organismal physiology-features available in few host study systems. Caenorhabditis elegans has proven to be an excellent genetic model organism to study innate immunity and, more recently, microbiome interactions. The study of C. elegans-pathogen interactions has provided in depth understanding of innate immune pathways, many of which are conserved in other animals. However, many bacteria were chosen for these studies because of their convenience in the lab setting or their implication in human health rather than their native interactions with C. elegans In their natural environment, C. elegans feed on a variety of bacteria found in rotting organic matter, such as rotting fruits, flowers, and stems. Recent work has begun to characterize the native microbiome and has identified a common set of bacteria found in the microbiome of C. elegans While some of these bacteria are beneficial to C. elegans health, others are detrimental, leading to a complex, multifaceted understanding of bacterium-nematode interactions. Current research on nematode-bacterium interactions is focused on these native microbiome components, both their interactions with each other and with C. elegans We will summarize our knowledge of bacterial pathogen-host interactions in C. elegans, as well as recent work on the native microbiome, and explore the incorporation of these bacterium-nematode interactions into studies of innate immunity and pathogenesis.
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Affiliation(s)
- Leah J Radeke
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Michael A Herman
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
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19
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Abstract
Animals live in symbiosis with numerous microbe species. While some can protect hosts from infection and benefit host health, components of the microbiota or changes to the microbial landscape have the potential to facilitate infections and worsen disease severity. Pathogens and pathobionts can exploit microbiota metabolites, or can take advantage of a depletion in host defences and changing conditions within a host, to cause opportunistic infection. The microbiota might also favour a more virulent evolutionary trajectory for invading pathogens. In this review, we consider the ways in which a host microbiota contributes to infectious disease throughout the host's life and potentially across evolutionary time. We further discuss the implications of these negative outcomes for microbiota manipulation and engineering in disease management.
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Affiliation(s)
- Emily J. Stevens
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Kieran A. Bates
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Kayla C. King
- Department of Zoology, University of Oxford, Oxford, United Kingdom
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20
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Vieira Dos Santos MC, Almeida MTM, Costa SR. First report of Meloidogyne naasi parasitizing turfgrass in Portugal. J Nematol 2021; 52:e2020-88. [PMID: 33829175 PMCID: PMC8015316 DOI: 10.21307/jofnem-2020-088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Indexed: 11/20/2022] Open
Abstract
In an exploratory sampling of a football field in Porto, Portugal, the root-knot nematode, Meloidogyne naasi, previously unreported from the Iberian Peninsula, was detected. Diagnosis was based on the analysis of perineal patterns and esterase phenotypes of females excised from grass roots, morphometrics and molecular analysis (PCR with specific primers and analysis of partial 28S sequences obtained by amplification using the primers D2A/D3B) of second-stage juveniles (J2) extracted from soil. When collected in water, J2 aggregated into a worm-star. Endospores of Pasteuria penetrans were frequently found attached to the J2. To our knowledge, this is the first report of M. naasi in Portugal and in the Iberian Peninsula, and the first report of worm-star formation in Meloidogyne.
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Affiliation(s)
- M Clara Vieira Dos Santos
- CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - M Teresa M Almeida
- CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Sofia R Costa
- CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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21
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Abstract
In its natural habitat, C. elegans encounters a wide variety of microbes, including food, commensals and pathogens. To be able to survive long enough to reproduce, C. elegans has developed a complex array of responses to pathogens. These activities are coordinated on scales that range from individual organelles to the entire organism. Often, the response is triggered within cells, by detection of infection-induced damage, mainly in the intestine or epidermis. C. elegans has, however, a capacity for cell non-autonomous regulation of these responses. This frequently involves the nervous system, integrating pathogen recognition, altering host biology and governing avoidance behavior. Although there are significant differences with the immune system of mammals, some mechanisms used to limit pathogenesis show remarkable phylogenetic conservation. The past 20 years have witnessed an explosion of host-pathogen interaction studies using C. elegans as a model. This review will discuss the broad themes that have emerged and highlight areas that remain to be fully explored.
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Affiliation(s)
- Céline N Martineau
- Aix Marseille Université, Inserm, CNRS, CIML, Turing Centre for Living Systems, Marseille, France
| | | | - Nathalie Pujol
- Aix Marseille Université, Inserm, CNRS, CIML, Turing Centre for Living Systems, Marseille, France.
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22
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Gravato-Nobre M, Hodgkin J, Ligoxygakis P. From pathogen to a commensal: modification of the Microbacterium nematophilum-Caenorhabditis elegans interaction during chronic infection by the absence of host insulin signalling. Biol Open 2020; 9:bio053504. [PMID: 32580971 PMCID: PMC7561485 DOI: 10.1242/bio.053504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 06/12/2020] [Indexed: 12/20/2022] Open
Abstract
The nematode worm Caenorhabditis elegans depends on microbes in decaying vegetation as its food source. To survive in an environment rich in opportunistic pathogens, Celegans has evolved an epithelial defence system where surface-exposed tissues such as epidermis, pharynx, intestine, vulva and hindgut have the capacity of eliciting appropriate immune defences to acute gut infection. However, it is unclear how the worm responds to chronic intestinal infections. To this end, we have surveyed Celegans mutants that are involved in inflammation, immunity and longevity to find their phenotypes during chronic infection. Worms that grew in a monoculture of the natural pathogen Microbacterium nematophilum (CBX102 strain) had a reduced lifespan and vigour. This was independent of intestinal colonisation as both CBX102 and the derived avirulent strain UV336 were early persistent colonisers. In contrast, the long-lived daf-2 mutant was resistant to chronic infection, showing reduced colonisation and higher vigour. In fact, UV336 interaction with daf-2 resulted in a host lifespan extension beyond OP50, the Escherichia coli strain used for laboratory Celegans culture. Longevity and vigour of daf-2 mutants growing on CBX102 was dependent on the FOXO orthologue DAF-16. Our results indicate that the interaction between host genotype and strain-specific bacteria determines longevity and health for C. elegans.
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Affiliation(s)
- Maria Gravato-Nobre
- Laboratory of Cell Biology, Development and Genetics, Department of Biochemistry, University of Oxford, South Parks Road, OX1 3QU Oxford, UK
| | - Jonathan Hodgkin
- Laboratory of Cell Biology, Development and Genetics, Department of Biochemistry, University of Oxford, South Parks Road, OX1 3QU Oxford, UK
| | - Petros Ligoxygakis
- Laboratory of Cell Biology, Development and Genetics, Department of Biochemistry, University of Oxford, South Parks Road, OX1 3QU Oxford, UK
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23
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Chan SY, Liu SY, Seng Z, Chua SL. Biofilm matrix disrupts nematode motility and predatory behavior. ISME JOURNAL 2020; 15:260-269. [PMID: 32958848 DOI: 10.1038/s41396-020-00779-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 09/09/2020] [Accepted: 09/14/2020] [Indexed: 01/09/2023]
Abstract
In nature, bacteria form biofilms by producing exopolymeric matrix that encases its entire community. While it is widely known that biofilm matrix can prevent bacterivore predation and contain virulence factors for killing predators, it is unclear if they can alter predator motility. Here, we report a novel "quagmire" phenotype, where Pseudomonas aeruginosa biofilms could retard the motility of bacterivorous nematode Caenorhabditis elegans via the production of a specific exopolysaccharide, Psl. Psl could reduce the roaming ability of C. elegans by impeding the slithering velocity of C. elegans. Furthermore, the presence of Psl in biofilms could entrap C. elegans within the matrix, with dire consequences to the nematode. After being trapped in biofilms, C. elegans could neither escape effectively from aversive stimuli (noxious blue light), nor leave easily to graze on susceptible biofilm areas. Hence, this reduced the ability of C. elegans to roam and predate on biofilms. Taken together, our work reveals a new function of motility interference by specific biofilm matrix components, and emphasizes its importance in predator-prey interactions.
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Affiliation(s)
- Shepherd Yuen Chan
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Sylvia Yang Liu
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Zijing Seng
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Song Lin Chua
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China. .,State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China.
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24
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Ke T, Santamaría A, Tinkov AA, Bornhorst J, Aschner M. Generating Bacterial Foods in Toxicology Studies with Caenorhabditis elegans. ACTA ACUST UNITED AC 2020; 84:e94. [PMID: 32436649 DOI: 10.1002/cptx.94] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Caenorhabditis elegans is a free-living animal that is used as a powerful experimental model in biological sciences. The natural habitat of the animal are areas rich in material from rotting plants or fruits being decomposed by a growing number of microorganisms. The ecology of the natural habitat of C. elegans is a complex interactive network involving many species, including numerous types of bacteria, viruses, fungi, slugs, snails, and isopods, among which bacteria play multifaceted roles in the natural history of C. elegans. Under laboratory conditions, C. elegans is routinely cultured in a petri dish filled with solidified agar and seeded with Escherichia coli strain OP50, the latter offering an alternative model to study the interaction between bacteria and host. Because of the clear advantages of generating specific bacterial foods for mechanistic studies in C. elegans, it is important to develop a robust protocol to generate high-quality bacterial foods commensurate with experimental requirements. Based on previous work by us and others, herein we present a protocol on how to generate these optimal bacterial food-based research tools. © 2020 by John Wiley & Sons, Inc. Basic Protocol 1: Preparing concentrated E. coli OP50 Basic Protocol 2: Titrating bacteria concentration Basic Protocol 3: Generating dead bacterial food by heating Basic Protocol 4: Generating dead bacterial food by antibiotics Basic Protocol 5: Feeding C. elegans with bacterial foods in liquid.
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Affiliation(s)
- Tao Ke
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York
| | - Abel Santamaría
- Laboratorio de Aminoácidos Excitadores, Instituto Nacional de Neurología y Neurocirugía, Mexico City, Mexico
| | - Alexey A Tinkov
- IM Sechenov First Moscow State Medical University, Sechenov University, Moscow, Russia.,Federal Research Centre of Biological Systems and Agro-technologies of the Russian Academy of Sciences, Orenburg, Russia.,Institute of Cellular and Intracellular Symbiosis, Russian Academy of Sciences, Orenburg, Russia
| | - Julia Bornhorst
- Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Wuppertal, Germany
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York.,IM Sechenov First Moscow State Medical University, Sechenov University, Moscow, Russia
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25
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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: 2.2] [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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26
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Hodgkin J. Nematode Autotomy Requires Molting and Entails Tissue Healing without Obvious Regeneration. J Dev Biol 2019; 7:jdb7040021. [PMID: 31771156 PMCID: PMC6955759 DOI: 10.3390/jdb7040021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/30/2019] [Accepted: 11/21/2019] [Indexed: 11/16/2022] Open
Abstract
Autotomy in C. elegans, which results in the severing of the body into two fragments, has been observed as a response to late larval worm-star formation after exposure to a bacterial surface pathogen. It was found that autotomy can occur in both hermaphroditic and gonochoristic nematode species, and during either the L3 or the L4 molt. Severing was hypothesized to be driven by a ‘balloon-twisting’ mechanism during molting but was found to be independent of lethargus-associated flipping. Extensive healing and apparent tissue fusion were seen at the site of scission. No obvious regeneration of lost body parts was seen in either L4 or adult truncated worms. A variety of mutants defective in processes of cell death, healing, regeneration, responses to damage, stress or pathogens were found to be competent to autotomize. Mutants specifically defective in autotomy have yet to be found. Autotomy may represent a modification of the essential normal process of molting.
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Affiliation(s)
- Jonathan Hodgkin
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
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27
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White PS, Penley MJ, Tierney ARP, Soper DM, Morran LT. Dauer life stage of Caenorhabditis elegans induces elevated levels of defense against the parasite Serratia marcescens. Sci Rep 2019; 9:11575. [PMID: 31399616 PMCID: PMC6688991 DOI: 10.1038/s41598-019-47969-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 07/23/2019] [Indexed: 01/17/2023] Open
Abstract
Host-parasite research often focuses on a single host life stage, yet different life stages may exhibit different defenses. The nematode Caenorhabditis elegans has an alternate dispersal life stage, dauer. Despite dauer's importance in nature, we know little of how it responds to parasites. Previous research indicates that non-dauer C. elegans prefer to consume the virulent bacterial parasite, Serratia marcescens, when given a choice between the parasite and benign Escherichia coli. Here, we compared the preferences of dauer individuals from six strains of C. elegans to the preferences of other life stages. We found that dauer individuals exhibited reduced preference for S. marcescens, and dauers from some strains preferred E. coli to S. marcescens. In addition to testing food preference, a mechanism of parasite avoidance, we also measured host mortality rates after direct parasite exposure to determine if life stage also altered host survival. Overall, dauer individuals exhibited reduced mortality rates. However, dauer versus non-dauer larvae mortality rates also varied significantly by host strain. Collectively, we found evidence of dauer-induced parasite avoidance and reduced mortality in the presence of a parasite, but these effects were strain-specific. These results demonstrate the importance of host life stage and genotype when assessing infection dynamics.
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Affiliation(s)
- P Signe White
- Population Biology, Ecology, and Evolution Graduate Program, Emory University, Atlanta, GA, 30322, USA.
- Department of Biology, Emory University, Atlanta, GA, 30322, USA.
| | - McKenna J Penley
- Department of Biology, Emory University, Atlanta, GA, 30322, USA
| | - Aimee R Paulk Tierney
- Microbiology and Molecular Genetics Graduate Program, Emory University, Atlanta, GA, 30322, USA
| | - Deanna M Soper
- Biology Department, University of Dallas, Irving, TX, 75062, USA
| | - Levi T Morran
- Department of Biology, Emory University, Atlanta, GA, 30322, USA
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28
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Lipodisqs for eukaryote lipidomics with retention of viability: Sensitivity and resistance to Leucobacter infection linked to C.elegans cuticle composition. Chem Phys Lipids 2019; 222:51-58. [DOI: 10.1016/j.chemphyslip.2019.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 11/18/2022]
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29
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Souza CD, Simpson-Louredo L, Mota HF, Faria YV, Cabral FDO, Colodette SDS, Canellas MEFC, Cucinelli ADES, Luna MDGD, Santos CDS, Moreira LDO, Mattos-Guaraldi AL. Virulence potential of Corynebacterium striatum towards Caenorhabditis elegans. Antonie van Leeuwenhoek 2019; 112:1331-1340. [PMID: 31055716 DOI: 10.1007/s10482-019-01265-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/10/2019] [Indexed: 11/25/2022]
Abstract
Corynebacterium striatum strains have been increasingly reported as etiological agents of nosocomial infections and outbreaks in industrialized and developing countries. However, there are few studies focused on the virulence potential of C. striatum. A growing body of research supports the use of Caenorhabditis elegans as a model host for investigating the virulence potential of pathogenic bacteria, including corynebacteria. In the present study, chemotaxis behaviour, mortality, and morphological changes were investigated in nematodes infected by four C. striatum strains isolated from different clinical sites, and with different MDR profiles and PFGE types. The results showed chemotaxis of nematodes towards C. striatum. Nematode death (> 60%) was detected from the first day post-infection with all strains tested, but at different levels, independent of biofilm formation on catheter surfaces and differences in growth temperature between nematodes (20 °C) and mammals (37 °C). C. striatum 2369/II multidrug-resistant (MDR; from tracheal aspirate of a patient undergoing endotracheal intubation) and 1961/III multidrug-sensitive (MDS; urine) strains led to 100% mortality in worms. Survival of nematodes was observed until 4 days post-infection with the C. striatum 1954/IV MDS strain isolated from a surgical wound (13%) and 1987/I MDR strain isolated from a patient with a lower respiratory tract infection (39%). The Dar phenotype was observed post-infection with all MDS and MDR strains except 1954/IV. All strains showed the capacity for bagging formation. Star formation was observed only with strains that led to 100% nematode mortality. In conclusion, C. striatum was found to exert virulence for C. elegans. Variations in nematode morphological changes and levels of mortality indicate differences in the virulence potential of C. striatum independent of clinical isolation site, capacity for biofilm formation, and MDR and PFGE profiles.
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Affiliation(s)
- Cassius de Souza
- Laboratory of Diphtheria and Corynebacteria of Clinical Relevance, The Collaborating Centre for Reference and Research on Diphtheria/National Health Foundation/Ministry of Health - FNS/MS, Brazil- LDCIC/FCM/UERJ, Faculty of Medical Sciences, State University of Rio de Janeiro - UERJ, Av. 28 de Setembro, 87 - Fundos, 3° andar, Vila Isabel, Rio de Janeiro, RJ, CEP 20551-030, Brazil
| | - Liliane Simpson-Louredo
- National Institute of Control and Quality in Health - Oswaldo Cruz Foundation, INCQS, Av. Brasil, 4365 - Manguinhos, Rio de Janeiro, RJ, CEP 21040-900, Brazil
| | - Higor Franceschi Mota
- Laboratory of Diphtheria and Corynebacteria of Clinical Relevance, The Collaborating Centre for Reference and Research on Diphtheria/National Health Foundation/Ministry of Health - FNS/MS, Brazil- LDCIC/FCM/UERJ, Faculty of Medical Sciences, State University of Rio de Janeiro - UERJ, Av. 28 de Setembro, 87 - Fundos, 3° andar, Vila Isabel, Rio de Janeiro, RJ, CEP 20551-030, Brazil
| | - Yuri Vieira Faria
- Laboratory of Diphtheria and Corynebacteria of Clinical Relevance, The Collaborating Centre for Reference and Research on Diphtheria/National Health Foundation/Ministry of Health - FNS/MS, Brazil- LDCIC/FCM/UERJ, Faculty of Medical Sciences, State University of Rio de Janeiro - UERJ, Av. 28 de Setembro, 87 - Fundos, 3° andar, Vila Isabel, Rio de Janeiro, RJ, CEP 20551-030, Brazil
| | - Fellipe de Oliveira Cabral
- Laboratory of Diphtheria and Corynebacteria of Clinical Relevance, The Collaborating Centre for Reference and Research on Diphtheria/National Health Foundation/Ministry of Health - FNS/MS, Brazil- LDCIC/FCM/UERJ, Faculty of Medical Sciences, State University of Rio de Janeiro - UERJ, Av. 28 de Setembro, 87 - Fundos, 3° andar, Vila Isabel, Rio de Janeiro, RJ, CEP 20551-030, Brazil
| | - Sabrina Dos Santos Colodette
- Laboratory of Diphtheria and Corynebacteria of Clinical Relevance, The Collaborating Centre for Reference and Research on Diphtheria/National Health Foundation/Ministry of Health - FNS/MS, Brazil- LDCIC/FCM/UERJ, Faculty of Medical Sciences, State University of Rio de Janeiro - UERJ, Av. 28 de Setembro, 87 - Fundos, 3° andar, Vila Isabel, Rio de Janeiro, RJ, CEP 20551-030, Brazil
| | - Maria E Freire Castro Canellas
- Laboratory of Diphtheria and Corynebacteria of Clinical Relevance, The Collaborating Centre for Reference and Research on Diphtheria/National Health Foundation/Ministry of Health - FNS/MS, Brazil- LDCIC/FCM/UERJ, Faculty of Medical Sciences, State University of Rio de Janeiro - UERJ, Av. 28 de Setembro, 87 - Fundos, 3° andar, Vila Isabel, Rio de Janeiro, RJ, CEP 20551-030, Brazil
| | - Andrezza do Espirito Santo Cucinelli
- Laboratory of Diphtheria and Corynebacteria of Clinical Relevance, The Collaborating Centre for Reference and Research on Diphtheria/National Health Foundation/Ministry of Health - FNS/MS, Brazil- LDCIC/FCM/UERJ, Faculty of Medical Sciences, State University of Rio de Janeiro - UERJ, Av. 28 de Setembro, 87 - Fundos, 3° andar, Vila Isabel, Rio de Janeiro, RJ, CEP 20551-030, Brazil
| | - Maria das Graças de Luna
- Laboratory of Diphtheria and Corynebacteria of Clinical Relevance, The Collaborating Centre for Reference and Research on Diphtheria/National Health Foundation/Ministry of Health - FNS/MS, Brazil- LDCIC/FCM/UERJ, Faculty of Medical Sciences, State University of Rio de Janeiro - UERJ, Av. 28 de Setembro, 87 - Fundos, 3° andar, Vila Isabel, Rio de Janeiro, RJ, CEP 20551-030, Brazil
| | - Cintia da Silva Santos
- Laboratory of Diphtheria and Corynebacteria of Clinical Relevance, The Collaborating Centre for Reference and Research on Diphtheria/National Health Foundation/Ministry of Health - FNS/MS, Brazil- LDCIC/FCM/UERJ, Faculty of Medical Sciences, State University of Rio de Janeiro - UERJ, Av. 28 de Setembro, 87 - Fundos, 3° andar, Vila Isabel, Rio de Janeiro, RJ, CEP 20551-030, Brazil
| | - Lílian de Oliveira Moreira
- Faculty of Pharmacy of Federal University of Rio de Janeiro, UFRJ, Av. Carlos Chagas Filho, 373 - Cidade Universitária, Rio de Janeiro, RJ, CEP 21941-170, Brazil
| | - Ana Luíza Mattos-Guaraldi
- Laboratory of Diphtheria and Corynebacteria of Clinical Relevance, The Collaborating Centre for Reference and Research on Diphtheria/National Health Foundation/Ministry of Health - FNS/MS, Brazil- LDCIC/FCM/UERJ, Faculty of Medical Sciences, State University of Rio de Janeiro - UERJ, Av. 28 de Setembro, 87 - Fundos, 3° andar, Vila Isabel, Rio de Janeiro, RJ, CEP 20551-030, Brazil.
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30
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Lev I, Bril R, Liu Y, Ceré LI, Rechavi O. Inter-generational consequences for growing Caenorhabditis elegans in liquid. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180125. [PMID: 30966881 PMCID: PMC6460074 DOI: 10.1098/rstb.2018.0125] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2018] [Indexed: 12/12/2022] Open
Abstract
In recent years, studies in Caenorhabditis elegans nematodes have shown that different stresses can generate multigenerational changes. Here, we show that worms that grow in liquid media, and also their plate-grown progeny, are different from worms whose ancestors were grown on plates. It has been suggested that C. elegans might encounter liquid environments in nature, although actual observations in the wild are few and far between. By contrast, in the laboratory, growing worms in liquid is commonplace, and often used as an alternative to growing worms on agar plates, to control the composition of the worms' diet, to starve (and synchronize) worms or to grow large populations for biochemical assays. We found that plate-grown descendants of M9 liquid medium-grown worms were longer than control worms, and the heritable effects were already apparent very early in development. We tested for the involvement of different known epigenetic inheritance mechanisms, but could not find a single mutant in which these inter-generational effects are cancelled. While we found that growing in liquid always leads to inter-generational changes in the worms' size, trans-generational effects were found to be variable, and in some cases, the effects were gone after one to two generations. These results demonstrate that standard cultivation conditions in early life can dramatically change the worms' physiology in adulthood, and can also affect the next generations. This article is part of the theme issue 'Developing differences: early-life effects and evolutionary medicine'.
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Affiliation(s)
- Itamar Lev
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Roberta Bril
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Yunan Liu
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Lucila Inés Ceré
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA
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31
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Infection Models: Novel Potato Blight-like Pathogens in Worms. Curr Biol 2018; 28:R273-R275. [DOI: 10.1016/j.cub.2018.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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32
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GIBSON AMANDAK, MORRAN LEVIT. A Model for Evolutionary Ecology of Disease: The Case for Caenorhabditis Nematodes and Their Natural Parasites. J Nematol 2018. [DOI: 10.21307/jofnem-2017-083] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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33
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Gibson AK, Morran LT. A Model for Evolutionary Ecology of Disease: The Case for Caenorhabditis Nematodes and Their Natural Parasites. J Nematol 2017; 49:357-372. [PMID: 29353923 PMCID: PMC5770282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Indexed: 06/07/2023] Open
Abstract
Many of the outstanding questions in disease ecology and evolution call for combining observation of natural host-parasite populations with experimental dissection of interactions in the field and the laboratory. The "rewilding" of model systems holds great promise for this endeavor. Here, we highlight the potential for development of the nematode Caenorhabditis elegans and its close relatives as a model for the study of disease ecology and evolution. This powerful laboratory model was disassociated from its natural habitat in the 1960s. Today, studies are uncovering that lost natural history, with several natural parasites described since 2008. Studies of these natural Caenorhabditis-parasite interactions can reap the benefits of the vast array of experimental and genetic tools developed for this laboratory model. In this review, we introduce the natural parasites of C. elegans characterized thus far and discuss resources available to study them, including experimental (co)evolution, cryopreservation, behavioral assays, and genomic tools. Throughout, we present avenues of research that are interesting and feasible to address with caenorhabditid nematodes and their natural parasites, ranging from the maintenance of outcrossing to the community dynamics of host-associated microbes. In combining natural relevance with the experimental power of a laboratory supermodel, these fledgling host-parasite systems can take on fundamental questions in evolutionary ecology of disease.
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Affiliation(s)
| | - Levi T Morran
- Department of Biology, Emory University, Atlanta, GA 30322
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34
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Dierking K, Yang W, Schulenburg H. Antimicrobial effectors in the nematode Caenorhabditis elegans: an outgroup to the Arthropoda. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0299. [PMID: 27160601 DOI: 10.1098/rstb.2015.0299] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2016] [Indexed: 12/14/2022] Open
Abstract
Nematodes and arthropods likely form the taxon Ecdysozoa. Information on antimicrobial effectors from the model nematode Caenorhabditis elegans may thus shed light on the evolutionary origin of these defences in arthropods. This nematode species possesses an extensive armory of putative antimicrobial effector proteins, such as lysozymes, caenopores (or saposin-like proteins), defensin-like peptides, caenacins and neuropeptide-like proteins, in addition to the production of reactive oxygen species and autophagy. As C. elegans is a bacterivore that lives in microbe-rich environments, some of its effector peptides and proteins likely function in both digestion of bacterial food and pathogen elimination. In this review, we provide an overview of C. elegans immune effector proteins and mechanisms. We summarize the experimental evidence of their antimicrobial function and involvement in the response to pathogen infection. We further evaluate the microbe-induced expression of effector genes using WormExp, a recently established database for C. elegans gene expression analysis. We emphasize the need for further analysis at the protein level to demonstrate an antimicrobial activity of these molecules both in vitro and in vivoThis article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.
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Affiliation(s)
- Katja Dierking
- Department of Evolutionary Ecology and Genetics, University of Kiel, Kiel 24098, Germany
| | - Wentao Yang
- Department of Evolutionary Ecology and Genetics, University of Kiel, Kiel 24098, Germany
| | - Hinrich Schulenburg
- Department of Evolutionary Ecology and Genetics, University of Kiel, Kiel 24098, Germany
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35
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Schulenburg H, Félix MA. The Natural Biotic Environment of Caenorhabditis elegans. Genetics 2017; 206:55-86. [PMID: 28476862 PMCID: PMC5419493 DOI: 10.1534/genetics.116.195511] [Citation(s) in RCA: 264] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 02/28/2017] [Indexed: 01/05/2023] Open
Abstract
Organisms evolve in response to their natural environment. Consideration of natural ecological parameters are thus of key importance for our understanding of an organism's biology. Curiously, the natural ecology of the model species Caenorhabditis elegans has long been neglected, even though this nematode has become one of the most intensively studied models in biological research. This lack of interest changed ∼10 yr ago. Since then, an increasing number of studies have focused on the nematode's natural ecology. Yet many unknowns still remain. Here, we provide an overview of the currently available information on the natural environment of C. elegans We focus on the biotic environment, which is usually less predictable and thus can create high selective constraints that are likely to have had a strong impact on C. elegans evolution. This nematode is particularly abundant in microbe-rich environments, especially rotting plant matter such as decomposing fruits and stems. In this environment, it is part of a complex interaction network, which is particularly shaped by a species-rich microbial community. These microbes can be food, part of a beneficial gut microbiome, parasites and pathogens, and possibly competitors. C. elegans is additionally confronted with predators; it interacts with vector organisms that facilitate dispersal to new habitats, and also with competitors for similar food environments, including competitors from congeneric and also the same species. Full appreciation of this nematode's biology warrants further exploration of its natural environment and subsequent integration of this information into the well-established laboratory-based research approaches.
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Affiliation(s)
- Hinrich Schulenburg
- Zoological Institute, Christian-Albrechts Universitaet zu Kiel, 24098 Kiel, Germany
| | - Marie-Anne Félix
- Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, École Normale Supérieure, L'université de Recherche Paris Sciences et Lettres, 75005, France
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36
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Ford SA, Williams D, Paterson S, King KC. Co-evolutionary dynamics between a defensive microbe and a pathogen driven by fluctuating selection. Mol Ecol 2016; 26:1778-1789. [PMID: 27862515 PMCID: PMC6849518 DOI: 10.1111/mec.13906] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 09/15/2016] [Accepted: 10/27/2016] [Indexed: 12/30/2022]
Abstract
Microbes that protect their hosts from pathogenic infection are widespread components of the microbiota of both plants and animals. It has been found that interactions between 'defensive' microbes and pathogens can be genotype-specific and even underlie the variation in host resistance to pathogenic infection. These observations suggest a dynamic co-evolutionary association between pathogens and defensive microbes, but direct evidence of co-evolution is lacking. We tested the hypothesis that defensive microbes and pathogens could co-evolve within host populations by co-passaging a microbe with host-defensive properties (Enterococcus faecalis) and a pathogen (Staphylococcus aureus) within Caenorhabditis elegans nematodes. Using both phenotypic and genomic analyses across evolutionary time, we found patterns of pathogen local adaptation and defensive microbe-pathogen co-evolution via fluctuating selection dynamics. Moreover, co-evolution with defensive microbes resulted in more rapid and divergent pathogen evolution compared to pathogens evolved independently in host populations. Taken together, our results indicate the potential for defensive microbes and pathogens to co-evolve, driving interaction specificity and pathogen evolutionary divergence in the absence of host evolution.
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Affiliation(s)
- Suzanne A Ford
- Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford, OX1 3PS, UK
| | - David Williams
- Centre for Genomic Research, Institute of Integrative Biology, University of Liverpool, Biosciences Building, Liverpool, L69 7ZB, UK
| | - Steve Paterson
- Centre for Genomic Research, Institute of Integrative Biology, University of Liverpool, Biosciences Building, Liverpool, L69 7ZB, UK
| | - Kayla C King
- Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford, OX1 3PS, UK
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37
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Kong C, Eng SA, Lim MP, Nathan S. Beyond Traditional Antimicrobials: A Caenorhabditis elegans Model for Discovery of Novel Anti-infectives. Front Microbiol 2016; 7:1956. [PMID: 27994583 PMCID: PMC5133244 DOI: 10.3389/fmicb.2016.01956] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 11/22/2016] [Indexed: 11/13/2022] Open
Abstract
The spread of antibiotic resistance amongst bacterial pathogens has led to an urgent need for new antimicrobial compounds with novel modes of action that minimize the potential for drug resistance. To date, the development of new antimicrobial drugs is still lagging far behind the rising demand, partly owing to the absence of an effective screening platform. Over the last decade, the nematode Caenorhabditis elegans has been incorporated as a whole animal screening platform for antimicrobials. This development is taking advantage of the vast knowledge on worm physiology and how it interacts with bacterial and fungal pathogens. In addition to allowing for in vivo selection of compounds with promising anti-microbial properties, the whole animal C. elegans screening system has also permitted the discovery of novel compounds targeting infection processes that only manifest during the course of pathogen infection of the host. Another advantage of using C. elegans in the search for new antimicrobials is that the worm itself is a source of potential antimicrobial effectors which constitute part of its immune defense response to thwart infections. This has led to the evaluation of effector molecules, particularly antimicrobial proteins and peptides (APPs), as candidates for further development as therapeutic agents. In this review, we provide an overview on use of the C. elegans model for identification of novel anti-infectives. We highlight some highly potential lead compounds obtained from C. elegans-based screens, particularly those that target bacterial virulence or host defense to eradicate infections, a mechanism distinct from the action of conventional antibiotics. We also review the prospect of using C. elegans APPs as an antimicrobial strategy to treat infections.
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Affiliation(s)
- Cin Kong
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia Bangi, Malaysia
| | - Su-Anne Eng
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia Bangi, Malaysia
| | - Mei-Perng Lim
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia Bangi, Malaysia
| | - Sheila Nathan
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia Bangi, Malaysia
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38
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Zhang G, Sachse M, Prevost MC, Luallen RJ, Troemel ER, Félix MA. A Large Collection of Novel Nematode-Infecting Microsporidia and Their Diverse Interactions with Caenorhabditis elegans and Other Related Nematodes. PLoS Pathog 2016; 12:e1006093. [PMID: 27942022 PMCID: PMC5179134 DOI: 10.1371/journal.ppat.1006093] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 12/22/2016] [Accepted: 11/28/2016] [Indexed: 12/26/2022] Open
Abstract
Microsporidia are fungi-related intracellular pathogens that may infect virtually all animals, but are poorly understood. The nematode Caenorhabditis elegans has recently become a model host for studying microsporidia through the identification of its natural microsporidian pathogen Nematocida parisii. However, it was unclear how widespread and diverse microsporidia infections are in C. elegans or other related nematodes in the wild. Here we describe the isolation and culture of 47 nematodes with microsporidian infections. N. parisii is found to be the most common microsporidia infecting C. elegans in the wild. In addition, we further describe and name six new species in the Nematocida genus. Our sampling and phylogenetic analysis further identify two subclades that are genetically distinct from Nematocida, and we name them Enteropsectra and Pancytospora. Interestingly, unlike Nematocida, these two genera belong to the main clade of microsporidia that includes human pathogens. All of these microsporidia are horizontally transmitted and most specifically infect intestinal cells, except Pancytospora epiphaga that replicates mostly in the epidermis of its Caenorhabditis host. At the subcellular level in the infected host cell, spores of the novel genus Enteropsectra show a characteristic apical distribution and exit via budding off of the plasma membrane, instead of exiting via exocytosis as spores of Nematocida. Host specificity is broad for some microsporidia, narrow for others: indeed, some microsporidia can infect Oscheius tipulae but not its sister species Oscheius sp. 3, and conversely some microsporidia found infecting Oscheius sp. 3 do not infect O. tipulae. We also show that N. ausubeli fails to strongly induce in C. elegans the transcription of genes that are induced by other Nematocida species, suggesting it has evolved mechanisms to prevent induction of this host response. Altogether, these newly isolated species illustrate the diversity and ubiquity of microsporidian infections in nematodes, and provide a rich resource to investigate host-parasite coevolution in tractable nematode hosts.
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Affiliation(s)
- Gaotian Zhang
- Institut de Biologie de l’Ecole Normale Supérieure, CNRS, Inserm, ENS, PSL Research University, Paris, France
- School of Life Sciences, East China Normal University, Shanghai, China
| | | | | | - Robert J. Luallen
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California, United States of America
| | - Emily R. Troemel
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California, United States of America
| | - Marie-Anne Félix
- Institut de Biologie de l’Ecole Normale Supérieure, CNRS, Inserm, ENS, PSL Research University, Paris, France
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39
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Ford SA, Kao D, Williams D, King KC. Microbe-mediated host defence drives the evolution of reduced pathogen virulence. Nat Commun 2016; 7:13430. [PMID: 27845328 PMCID: PMC5116080 DOI: 10.1038/ncomms13430] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 10/03/2016] [Indexed: 12/30/2022] Open
Abstract
Microbes that protect their hosts from pathogens are widespread in nature and are attractive disease control agents. Given that pathogen adaptation to barriers against infection can drive changes in pathogen virulence, 'defensive microbes' may shape disease severity. Here we show that co-evolving a microbe with host-protective properties (Enterococcus faecalis) and a pathogen (Staphylococcus aureus) within Caenorhabditis elegans hosts drives the evolution of reduced pathogen virulence as a by-product of adaptation to the defensive microbe. Using both genomic and phenotypic analyses, we discover that the production of fewer iron-scavenging siderophores by the pathogen reduces the fitness of the defensive microbe and underpins the decline in pathogen virulence. These data show that defensive microbes can shape the evolution of pathogen virulence and that the mechanism of pathogen resistance can determine the direction of virulence evolution.
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Affiliation(s)
- Suzanne A Ford
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - Damian Kao
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - David Williams
- Centre for Genomic Research, Institute of Integrative Biology, University of Liverpool, Biosciences Building, Liverpool L69 7ZB UK
| | - Kayla C King
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
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40
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Samuel BS, Rowedder H, Braendle C, Félix MA, Ruvkun G. Caenorhabditis elegans responses to bacteria from its natural habitats. Proc Natl Acad Sci U S A 2016; 113:E3941-9. [PMID: 27317746 PMCID: PMC4941482 DOI: 10.1073/pnas.1607183113] [Citation(s) in RCA: 253] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Most Caenorhabditis elegans studies have used laboratory Escherichia coli as diet and microbial environment. Here we characterize bacteria of C. elegans' natural habitats of rotting fruits and vegetation to provide greater context for its physiological responses. By the use of 16S ribosomal DNA (rDNA)-based sequencing, we identified a large variety of bacteria in C. elegans habitats, with phyla Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria being most abundant. From laboratory assays using isolated natural bacteria, C. elegans is able to forage on most bacteria (robust growth on ∼80% of >550 isolates), although ∼20% also impaired growth and arrested and/or stressed animals. Bacterial community composition can predict wild C. elegans population states in both rotting apples and reconstructed microbiomes: alpha-Proteobacteria-rich communities promote proliferation, whereas Bacteroidetes or pathogens correlate with nonproliferating dauers. Combinatorial mixtures of detrimental and beneficial bacteria indicate that bacterial influence is not simply nutritional. Together, these studies provide a foundation for interrogating how bacteria naturally influence C. elegans physiology.
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Affiliation(s)
- Buck S Samuel
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114
| | - Holli Rowedder
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114
| | - Christian Braendle
- CNRS, INSERM, Institute of Biology Valrose, University of Nice Sophia Antipolis, Parc Valrose, 06108 Nice, France
| | - Marie-Anne Félix
- Institute of Biology of the Ecole Normale Supérieure, CNRS UMR8197, Ecole Normale Supérieure, INSERM U1024, 75005 Paris, France
| | - Gary Ruvkun
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114;
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41
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King KC, Brockhurst MA, Vasieva O, Paterson S, Betts A, Ford SA, Frost CL, Horsburgh MJ, Haldenby S, Hurst GD. Rapid evolution of microbe-mediated protection against pathogens in a worm host. ISME JOURNAL 2016; 10:1915-24. [PMID: 26978164 PMCID: PMC5029159 DOI: 10.1038/ismej.2015.259] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 11/23/2015] [Accepted: 12/01/2015] [Indexed: 12/16/2022]
Abstract
Microbes can defend their host against virulent infections, but direct evidence for the adaptive origin of microbe-mediated protection is lacking. Using experimental evolution of a novel, tripartite interaction, we demonstrate that mildly pathogenic bacteria (Enterococcus faecalis) living in worms (Caenorhabditis elegans) rapidly evolved to defend their animal hosts against infection by a more virulent pathogen (Staphylococcus aureus), crossing the parasitism–mutualism continuum. Host protection evolved in all six, independently selected populations in response to within-host bacterial interactions and without direct selection for host health. Microbe-mediated protection was also effective against a broad spectrum of pathogenic S. aureus isolates. Genomic analysis implied that the mechanistic basis for E. faecalis-mediated protection was through increased production of antimicrobial superoxide, which was confirmed by biochemical assays. Our results indicate that microbes living within a host may make the evolutionary transition to mutualism in response to pathogen attack, and that microbiome evolution warrants consideration as a driver of infection outcome.
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Affiliation(s)
- Kayla C King
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK.,Department of Zoology, University of Oxford, Oxford, UK
| | | | - Olga Vasieva
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Steve Paterson
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Alex Betts
- Department of Zoology, University of Oxford, Oxford, UK
| | | | - Crystal L Frost
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | | | - Sam Haldenby
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Gregory Dd Hurst
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
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42
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Assembly of the Caenorhabditis elegans gut microbiota from diverse soil microbial environments. ISME JOURNAL 2016; 10:1998-2009. [PMID: 26800234 PMCID: PMC5029150 DOI: 10.1038/ismej.2015.253] [Citation(s) in RCA: 241] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 11/22/2015] [Accepted: 12/01/2015] [Indexed: 01/15/2023]
Abstract
It is now well accepted that the gut microbiota contributes to our health. However, what determines the microbiota composition is still unclear. Whereas it might be expected that the intestinal niche would be dominant in shaping the microbiota, studies in vertebrates have repeatedly demonstrated dominant effects of external factors such as host diet and environmental microbial diversity. Hypothesizing that genetic variation may interfere with discerning contributions of host factors, we turned to Caenorhabditis elegans as a new model, offering the ability to work with genetically homogenous populations. Deep sequencing of 16S rDNA was used to characterize the (previously unknown) worm gut microbiota as assembled from diverse produce-enriched soil environments under laboratory conditions. Comparisons of worm microbiotas with those in their soil environment revealed that worm microbiotas resembled each other even when assembled from different microbial environments, and enabled defining a shared core gut microbiota. Community analyses indicated that species assortment in the worm gut was non-random and that assembly rules differed from those in their soil habitat, pointing at the importance of competitive interactions between gut-residing taxa. The data presented fills a gap in C. elegans biology. Furthermore, our results demonstrate a dominant contribution of the host niche in shaping the gut microbiota.
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43
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Abstract
Be it their pervasiveness, experimental tractability or their impact on human health and agriculture, nematode–bacterium associations are far-reaching research subjects. Although the omics hype did not spare them and helped reveal mechanisms of communication and exchange between the associated partners, a huge amount of knowledge still awaits to be harvested from their study. Here, I summarize and compare the kind of research that has been already performed on the model nematode Caenorhabditis elegans and on symbiotic nematodes, both marine and entomopathogenic ones. The emerging picture highlights how complementing genetic studies with ecological ones (in the case of well-established genetic model systems such as C. elegans) and vice versa (in the case of the yet uncultured Stilbonematinae) will deepen our understanding of how microbial symbioses evolved and how they impact our environment. Nematode–bacterium associations are major research subjects. Complementing genetic studies with ecological ones is necessary to boost our understanding of how microbial symbioses evolved and how they impact the environment.
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Affiliation(s)
- Silvia Bulgheresi
- Department of Ecogenomics and Systems Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
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44
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Antunes CA, Clark L, Wanuske MT, Hacker E, Ott L, Simpson-Louredo L, de Luna MDG, Hirata R, Mattos-Guaraldi AL, Hodgkin J, Burkovski A. Caenorhabditis elegans star formation and negative chemotaxis induced by infection with corynebacteria. MICROBIOLOGY-SGM 2015; 162:84-93. [PMID: 26490043 DOI: 10.1099/mic.0.000201] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Caenorhabditis elegans is one of the major model systems in biology based on advantageous properties such as short life span, transparency, genetic tractability and ease of culture using an Escherichia coli diet. In its natural habitat, compost and rotting plant material, this nematode lives on bacteria. However, C. elegans is a predator of bacteria, but can also be infected by nematopathogenic coryneform bacteria such Microbacterium and Leucobacter species, which display intriguing and diverse modes of pathogenicity. Depending on the nematode pathogen, aggregates of worms, termed worm-stars, can be formed, or severe rectal swelling, so-called Dar formation, can be induced. Using the human and animal pathogens Corynebacterium diphtheriae and Corynebacterium ulcerans as well as the non-pathogenic species Corynebacterium glutamicum, we show that these coryneform bacteria can also induce star formation slowly in worms, as well as a severe tail-swelling phenotype. While C. glutamicum had a significant, but minor influence on survival of C. elegans, nematodes were killed after infection with C. diphtheriae and C. ulcerans. The two pathogenic species were avoided by the nematodes and induced aversive learning in C. elegans.
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Affiliation(s)
- Camila Azevedo Antunes
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Belo Horizonte, MG, Brazil.,Faculty of Medical Sciences, Rio de Janeiro State University, UERJ, Rio de Janeiro, RJ, Brazil
| | - Laura Clark
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Elena Hacker
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Lisa Ott
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Liliane Simpson-Louredo
- Faculty of Medical Sciences, Rio de Janeiro State University, UERJ, Rio de Janeiro, RJ, Brazil
| | | | - Raphael Hirata
- Faculty of Medical Sciences, Rio de Janeiro State University, UERJ, Rio de Janeiro, RJ, Brazil
| | | | | | - Andreas Burkovski
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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45
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Taffoni C, Pujol N. Mechanisms of innate immunity in C. elegans epidermis. Tissue Barriers 2015; 3:e1078432. [PMID: 26716073 PMCID: PMC4681281 DOI: 10.1080/21688370.2015.1078432] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 07/17/2015] [Accepted: 07/24/2015] [Indexed: 01/26/2023] Open
Abstract
The roundworm C. elegans has been successfully used for more than 50 y as a genetically tractable invertebrate model in diverse biological fields such as neurobiology, development and interactions. C. elegans feeds on bacteria and can be naturally infected by a wide range of microorganisms, including viruses, bacteria and fungi. Most of these pathogens infect C. elegans through its gut, but some have developed ways to infect the epidermis. In this review, we will mainly focus on epidermal innate immunity, in particular the signaling pathways and effectors activated upon wounding and fungal infection that serve to protect the host. We will discuss the parallels that exist between epidermal innate immune responses in nematodes and mammals.
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Affiliation(s)
- Clara Taffoni
- Center d'Immunologie de Marseille-Luminy; Aix Marseille Université UM2 ; Inserm; Marseille, France
| | - Nathalie Pujol
- Center d'Immunologie de Marseille-Luminy; Aix Marseille Université UM2 ; Inserm; Marseille, France
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46
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Clark LC, Hodgkin J. Leucobacter musarum subsp. musarum sp. nov., subsp. nov., Leucobacter musarum subsp. japonicus subsp. nov., and Leucobacter celer subsp. astrifaciens subsp. nov., three nematopathogenic bacteria isolated from Caenorhabditis, with an emended description of Leucobacter celer. Int J Syst Evol Microbiol 2015; 65:3977-3984. [PMID: 26275616 PMCID: PMC4804768 DOI: 10.1099/ijsem.0.000523] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Three Gram-stain-positive, irregular-rod-shaped, non-motile, non-spore-forming bacteria were isolated from nematodes collected from Santa Antao, Cabo Verde (CBX151T, CBX152T) and Kakegawa, Japan (CBX130T). Based on 16S rRNA gene sequence similarity, strains CBX130T, CBX151T and CBX152T were shown to belong to the genus Leucobacter. This affiliation was supported by chemotaxonomic data (2,4-diaminobutyric acid in the cell wall; major respiratory quinones MK-10 and MK-11; major polar lipids phosphatidylglycerol and diphosphatidylglycerol; major fatty acids anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0). Strains CBX130T and CBX152T were found to share salient characteristics. Based on morphological, physiological, chemotaxonomic and biochemical analysis, strain CBX152T represents a novel species of the genus Leucobacter, for which the name Leucobacter musarum sp. nov. (type strain CBX152T = DSM 27160T = CIP 110721T) is proposed. Two subspecies of Leucobacter musarum sp. nov. are proposed: Leucobacter musarum sp. nov. subsp. musarum subsp. nov. (type strain CBX152T = DSM 27160T = CIP 110721T) and Leucobacter musarum sp. nov. subsp. japonicus subsp. nov. (type strain CBX130T = DSM 27158T = CIP 110719T). The third novel strain, CBX151T, showed genetic similarities with Leucobacter celer NAL101T indicating that these strains belong to the same species. Based on morphological, physiological, chemotaxonomic and biochemical differences it is proposed to split the species Leucobacter celer into two novel subspecies, Leucobacter celer subsp. celer subsp. nov. (type strain NAL101T = KACC 14220T = JCM 16465T) and Leucobacter celer subsp. astrifaciens subsp. nov. (type strain CBX151T = DSM 27159T = CIP 110720T), and to emend the description of Leucobacter celerShin et al. 2011.
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Affiliation(s)
- Laura C Clark
- Biochemistry Department, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Jonathan Hodgkin
- Biochemistry Department, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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47
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Loer CM, Calvo AC, Watschinger K, Werner-Felmayer G, O'Rourke D, Stroud D, Tong A, Gotenstein JR, Chisholm AD, Hodgkin J, Werner ER, Martinez A. Cuticle integrity and biogenic amine synthesis in Caenorhabditis elegans require the cofactor tetrahydrobiopterin (BH4). Genetics 2015; 200:237-53. [PMID: 25808955 PMCID: PMC4423366 DOI: 10.1534/genetics.114.174110] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 03/12/2015] [Indexed: 11/18/2022] Open
Abstract
Tetrahydrobiopterin (BH4) is the natural cofactor of several enzymes widely distributed among eukaryotes, including aromatic amino acid hydroxylases (AAAHs), nitric oxide synthases (NOSs), and alkylglycerol monooxygenase (AGMO). We show here that the nematode Caenorhabditis elegans, which has three AAAH genes and one AGMO gene, contains BH4 and has genes that function in BH4 synthesis and regeneration. Knockout mutants for putative BH4 synthetic enzyme genes lack the predicted enzymatic activities, synthesize no BH4, and have indistinguishable behavioral and neurotransmitter phenotypes, including serotonin and dopamine deficiency. The BH4 regeneration enzymes are not required for steady-state levels of biogenic amines, but become rate limiting in conditions of reduced BH4 synthesis. BH4-deficient mutants also have a fragile cuticle and are generally hypersensitive to exogenous agents, a phenotype that is not due to AAAH deficiency, but rather to dysfunction in the lipid metabolic enzyme AGMO, which is expressed in the epidermis. Loss of AGMO or BH4 synthesis also specifically alters the sensitivity of C. elegans to bacterial pathogens, revealing a cuticular function for AGMO-dependent lipid metabolism in host-pathogen interactions.
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Affiliation(s)
- Curtis M Loer
- Department of Biology, University of San Diego, San Diego, California, 92110
| | - Ana C Calvo
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway
| | - Katrin Watschinger
- Division of Biological Chemistry, Biocenter, Innsbruck Medical University, A-6020 Innsbruck, Austria
| | - Gabriele Werner-Felmayer
- Division of Biological Chemistry, Biocenter, Innsbruck Medical University, A-6020 Innsbruck, Austria
| | - Delia O'Rourke
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Dave Stroud
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Amy Tong
- Division of Biological Sciences, University of California, San Diego, California 92093
| | - Jennifer R Gotenstein
- Division of Biological Sciences, University of California, San Diego, California 92093
| | - Andrew D Chisholm
- Division of Biological Sciences, University of California, San Diego, California 92093
| | - Jonathan Hodgkin
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Ernst R Werner
- Division of Biological Chemistry, Biocenter, Innsbruck Medical University, A-6020 Innsbruck, Austria
| | - Aurora Martinez
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway
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48
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Abstract
The roundworm Caenorhabditis elegans has risen to the status of a top model organism for biological research in the last fifty years. Among laboratory animals, this tiny nematode is one of the simplest and easiest organisms to handle. And its life outside the laboratory is beginning to be unveiled. Like other model organisms, C. elegans has a boom-and-bust lifestyle. It feasts on ephemeral bacterial blooms in decomposing fruits and stems. After resource depletion, its young larvae enter a migratory diapause stage, called the dauer. Organisms known to be associated with C. elegans include migration vectors (such as snails, slugs and isopods) and pathogens (such as microsporidia, fungi, bacteria and viruses). By deepening our understanding of the natural history of C. elegans, we establish a broader context and improved tools for studying its biology.
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Affiliation(s)
- Lise Frézal
- Institute of Biology of Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Paris, France
| | - Marie-Anne Félix
- Institute of Biology of Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Paris, France
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49
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Cohen LB, Troemel ER. Microbial pathogenesis and host defense in the nematode C. elegans. Curr Opin Microbiol 2015; 23:94-101. [PMID: 25461579 PMCID: PMC4324121 DOI: 10.1016/j.mib.2014.11.009] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/11/2014] [Accepted: 11/13/2014] [Indexed: 12/13/2022]
Abstract
Epithelial cells line the surfaces of the body, and are on the front lines of defense against microbial infection. Like many other metazoans, the nematode Caenorhabditis elegans lacks known professional immune cells and relies heavily on defense mediated by epithelial cells. New results indicate that epithelial defense in C. elegans can be triggered through detection of pathogen-induced perturbation of core physiology within host cells and through autophagic defense against intracellular and extracellular pathogens. Recent studies have also illuminated a diverse array of pathogenic attack strategies used against C. elegans. These findings are providing insight into the underpinnings of host/pathogen interactions in a simple animal host that can inform studies of infectious diseases in humans.
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Affiliation(s)
- Lianne B Cohen
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, United States
| | - Emily R Troemel
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, United States.
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50
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Petersen C, Dirksen P, Schulenburg H. Why we need more ecology for genetic models such as C. elegans. Trends Genet 2015; 31:120-7. [PMID: 25577479 DOI: 10.1016/j.tig.2014.12.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 12/08/2014] [Accepted: 12/09/2014] [Indexed: 12/28/2022]
Abstract
Functional information about the large majority of the genes is still lacking in the classical eukaryotic model species Drosophila melanogaster, Caenorhabditis elegans, and Mus musculus. Because many of these genes are likely to be important in natural settings, considering explicit ecological information should increase our knowledge of gene function. Using C. elegans as an example, we discuss the importance of biotic factors as a driving force in shaping the composition and structure of the nematode genome. We highlight examples for which consideration of ecological information and natural variation have been key to the identification of novel, unexpected gene functions, and use these examples to define future research avenues for the classical genetic model taxa.
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Affiliation(s)
- Carola Petersen
- Evolutionary Ecology and Genetics, University of Kiel, 24098 Kiel, Germany
| | - Philipp Dirksen
- Evolutionary Ecology and Genetics, University of Kiel, 24098 Kiel, Germany
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