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Naga NG, Shaaban MI, El-Metwally MM. An insight on the powerful of bacterial quorum sensing inhibition. Eur J Clin Microbiol Infect Dis 2024:10.1007/s10096-024-04920-w. [PMID: 39158799 DOI: 10.1007/s10096-024-04920-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 07/31/2024] [Indexed: 08/20/2024]
Abstract
Bacteria have their own language through which they communicate with one another like all higher organisms. So, many researchers are working hard to identify and comprehend the components of this bacterial communication, known as quorum sensing (QS). In quorum sensing, bacteria use signaling molecules called autoinducers (AIs) to exchange information. Many natural compounds and extraction techniques have been intensively studied to disrupt bacterial signaling and examine their effectiveness for bacterial pathogenesis control. Quorum sensing inhibitors can interfere with QS and block the action of AI signaling molecules. Recent research indicates that quorum sensing inhibitors (QSIs) and quorum quenching enzymes (QQEs) show great promise in reducing the pathogenicity of bacteria and inhibiting biofilm synthesis. In addition, the effectiveness of QQEs and QSIs in experimental animal models was demonstrated. These are taken into account in the development of innovative medical devices, such as dressings and catheters, to prevent bacterial infections. The present review highlights this aspect with a prospective vision for its development and application.
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Affiliation(s)
- Nourhan G Naga
- Botany and Microbiology Department, Faculty of Science, Alexandria University, Alexandria, Egypt.
| | - Mona I Shaaban
- Microbiology and Immunology Department, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
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2
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Feng D, Qu L, Powell-Coffman JA. Transcriptome analyses describe the consequences of persistent HIF-1 over-activation in Caenorhabditis elegans. PLoS One 2024; 19:e0295093. [PMID: 38517909 PMCID: PMC10959373 DOI: 10.1371/journal.pone.0295093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 02/20/2024] [Indexed: 03/24/2024] Open
Abstract
Metazoan animals rely on oxygen for survival, but during normal development and homeostasis, animals are often challenged by hypoxia (low oxygen). In metazoans, many of the critical hypoxia responses are mediated by the evolutionarily conserved hypoxia-inducible transcription factors (HIFs). The stability and activity of HIF complexes are strictly regulated. In the model organism C. elegans, HIF-1 stability and activity are negatively regulated by VHL-1, EGL-9, RHY-1 and SWAN-1. Importantly, C. elegans mutants carrying strong loss-of-function mutations in these genes are viable, and this provides opportunities to interrogate the molecular consequences of persistent HIF-1 over-activation. We find that the genome-wide gene expression patterns are compellingly similar in these mutants, supporting models in which RHY-1, VHL-1 and EGL-9 function in common pathway(s) to regulate HIF-1 activity. These studies illuminate the diversified biological roles played by HIF-1, including metabolism and stress response. Genes regulated by persistent HIF-1 over-activation overlap with genes responsive to pathogens, and they overlap with genes regulated by DAF-16. As crucial stress regulators, HIF-1 and DAF-16 converge on key stress-responsive genes and function synergistically to enable hypoxia survival.
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Affiliation(s)
- Dingxia Feng
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
| | - Long Qu
- Department of Statistics, Iowa State University, Ames, Iowa, United States of America
| | - Jo Anne Powell-Coffman
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
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3
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Warnhoff K, Bhattacharya S, Snoozy J, Breen PC, Ruvkun G. Hypoxia-inducible factor induces cysteine dioxygenase and promotes cysteine homeostasis in Caenorhabditis elegans. eLife 2024; 12:RP89173. [PMID: 38349720 PMCID: PMC10942545 DOI: 10.7554/elife.89173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024] Open
Abstract
Dedicated genetic pathways regulate cysteine homeostasis. For example, high levels of cysteine activate cysteine dioxygenase, a key enzyme in cysteine catabolism in most animal and many fungal species. The mechanism by which cysteine dioxygenase is regulated is largely unknown. In an unbiased genetic screen for mutations that activate cysteine dioxygenase (cdo-1) in the nematode Caenorhabditis elegans, we isolated loss-of-function mutations in rhy-1 and egl-9, which encode proteins that negatively regulate the stability or activity of the oxygen-sensing hypoxia inducible transcription factor (hif-1). EGL-9 and HIF-1 are core members of the conserved eukaryotic hypoxia response. However, we demonstrate that the mechanism of HIF-1-mediated induction of cdo-1 is largely independent of EGL-9 prolyl hydroxylase activity and the von Hippel-Lindau E3 ubiquitin ligase, the classical hypoxia signaling pathway components. We demonstrate that C. elegans cdo-1 is transcriptionally activated by high levels of cysteine and hif-1. hif-1-dependent activation of cdo-1 occurs downstream of an H2S-sensing pathway that includes rhy-1, cysl-1, and egl-9. cdo-1 transcription is primarily activated in the hypodermis where it is also sufficient to drive sulfur amino acid metabolism. Thus, the regulation of cdo-1 by hif-1 reveals a negative feedback loop that maintains cysteine homeostasis. High levels of cysteine stimulate the production of an H2S signal. H2S then acts through the rhy-1/cysl-1/egl-9 signaling pathway to increase HIF-1-mediated transcription of cdo-1, promoting degradation of cysteine via CDO-1.
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Affiliation(s)
- Kurt Warnhoff
- Pediatrics and Rare Diseases Group, Sanford ResearchSioux FallsUnited States
- Department of Pediatrics, Sanford School of Medicine, University of South DakotaSioux FallsUnited States
| | | | - Jennifer Snoozy
- Pediatrics and Rare Diseases Group, Sanford ResearchSioux FallsUnited States
| | - Peter C Breen
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
| | - Gary Ruvkun
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
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4
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Ambreetha S, Zincke D, Balachandar D, Mathee K. Genomic and metabolic versatility of Pseudomonas aeruginosa contributes to its inter-kingdom transmission and survival. J Med Microbiol 2024; 73. [PMID: 38362900 DOI: 10.1099/jmm.0.001791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024] Open
Abstract
Pseudomonas aeruginosa is one of the most versatile bacteria with renowned pathogenicity and extensive drug resistance. The diverse habitats of this bacterium include fresh, saline and drainage waters, soil, moist surfaces, taps, showerheads, pipelines, medical implants, nematodes, insects, plants, animals, birds and humans. The arsenal of virulence factors produced by P. aeruginosa includes pyocyanin, rhamnolipids, siderophores, lytic enzymes, toxins and polysaccharides. All these virulent elements coupled with intrinsic, adaptive and acquired antibiotic resistance facilitate persistent colonization and lethal infections in different hosts. To date, treating pulmonary diseases remains complicated due to the chronic secondary infections triggered by hospital-acquired P. aeruginosa. On the contrary, this bacterium can improve plant growth by suppressing phytopathogens and insects. Notably, P. aeruginosa is one of the very few bacteria capable of trans-kingdom transmission and infection. Transfer of P. aeruginosa strains from plant materials to hospital wards, animals to humans, and humans to their pets occurs relatively often. Recently, we have identified that plant-associated P. aeruginosa strains could be pathologically similar to clinical isolates. In this review, we have highlighted the genomic and metabolic factors that facilitate the dominance of P. aeruginosa across different biological kingdoms and the varying roles of this bacterium in plant and human health.
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Affiliation(s)
- Sakthivel Ambreetha
- Developmental Biology and Genetics, Division of Biological Sciences, Indian Institute of Science, Bengaluru, Karnataka, 560012, India
| | - Diansy Zincke
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA
| | - Dananjeyan Balachandar
- Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore, 641003, Tamil Nadu, India
| | - Kalai Mathee
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA
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5
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Peng B, Li Y, Yin J, Ding W, Fazuo W, Xiao Z, Yin H. A bibliometric analysis on discovering anti-quorum sensing agents against clinically relevant pathogens: current status, development, and future directions. Front Microbiol 2023; 14:1297843. [PMID: 38098670 PMCID: PMC10720721 DOI: 10.3389/fmicb.2023.1297843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 11/10/2023] [Indexed: 12/17/2023] Open
Abstract
Background Quorum sensing is bacteria's ability to communicate and regulate their behavior based on population density. Anti-quorum sensing agents (anti-QSA) is promising strategy to treat resistant infections, as well as reduce selective pressure that leads to antibiotic resistance of clinically relevant pathogens. This study analyzes the output, hotspots, and trends of research in the field of anti-QSA against clinically relevant pathogens. Methods The literature on anti-QSA from the Web of Science Core Collection database was retrieved and analyzed. Tools such as CiteSpace and Alluvial Generator were used to visualize and interpret the data. Results From 1998 to 2023, the number of publications related to anti-QAS research increased rapidly, with a total of 1,743 articles and reviews published in 558 journals. The United States was the largest contributor and the most influential country, with an H-index of 88, higher than other countries. Williams was the most productive author, and Hoiby N was the most cited author. Frontiers in Microbiology was the most prolific and the most cited journal. Burst detection indicated that the main frontier disciplines shifted from MICROBIOLOGY, CLINICAL, MOLECULAR BIOLOGY, and other biomedicine-related fields to FOOD, MATERIALS, NATURAL PRODUCTS, and MULTIDISCIPLINARY. In the whole research history, the strongest burst keyword was cystic-fibrosis patients, and the strongest burst reference was Lee and Zhang (2015). In the latest period (burst until 2023), the strongest burst keyword was silver nanoparticle, and the strongest burst reference was Whiteley et al. (2017). The co-citation network revealed that the most important interest and research direction was anti-biofilm/anti-virulence drug development, and timeline analysis suggested that this direction is also the most active. The key concepts alluvial flow visualization revealed seven terms with the longest time span and lasting until now, namely Escherichia coli, virulence, Pseudomonas aeruginosa, virulence factor, bacterial biofilm, gene expression, quorum sensing. Comprehensive analysis shows that nanomaterials, marine natural products, and artificial intelligence (AI) may become hotspots in the future. Conclusion This bibliometric study reveals the current status and trends of anti-QSA research and may assist researchers in identifying hot topics and exploring new research directions.
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Affiliation(s)
- Bo Peng
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China
| | - Yanqun Li
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Jiajia Yin
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Wenping Ding
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Wang Fazuo
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Zhihui Xiao
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Hao Yin
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
- Sanya Institute of Ocean Eco-Environmental Engineering, Sanya, China
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6
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Feng D, Qu L. Transcriptome analyses describe the consequences of persistent HIF-1 over-activation in Caenorhabditis elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.15.567311. [PMID: 38014086 PMCID: PMC10680707 DOI: 10.1101/2023.11.15.567311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Metazoan animals rely on oxygen for survival, but during normal development and homeostasis, animals are often challenged by hypoxia (low oxygen). In metazoans, many of the critical hypoxia responses are mediated by the evolutionarily conserved hypoxia-inducible transcription factors (HIFs). The stability and activity of HIF complexes are strictly regulated. In the model organism C. elegans, HIF-1 stability and activity are negatively regulated by VHL-1, EGL-9, RHY-1 and SWAN-1. Importantly, C. elegans mutants carrying strong loss-of-function mutations in these genes are viable, and this provides opportunities to interrogate the molecular consequences of persistent HIF-1 over-activation. We find that the genome-wide gene expression patterns are compellingly similar in these mutants, supporting models in which RHY-1, SWAN-1 and EGL-9 function in common pathway(s) to regulate HIF-1 activity. These studies illuminate the diversified biological roles played by HIF-1, including metabolism, hypoxia and other stress responses, reproduction and development. Genes regulated by persistent HIF-1 over-activation overlap with genes responsive to pathogens, and they overlap with genes regulated by DAF-16. As crucial stress regulators, HIF-1 and DAF-16 converge on key stress-responsive genes and function synergistically to enable hypoxia survival.
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Affiliation(s)
- Dingxia Feng
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
| | - Long Qu
- Department of Statistics, Iowa State University, Ames, Iowa, United States of America
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7
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Warnhoff K, Bhattacharya S, Snoozy J, Breen PC, Ruvkun G. Hypoxia-inducible factor induces cysteine dioxygenase and promotes cysteine homeostasis in Caenorhabditis elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.04.538701. [PMID: 37205365 PMCID: PMC10187278 DOI: 10.1101/2023.05.04.538701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Dedicated genetic pathways regulate cysteine homeostasis. For example, high levels of cysteine activate cysteine dioxygenase, a key enzyme in cysteine catabolism in most animal and many fungal species. The mechanism by which cysteine dioxygenase is regulated is largely unknown. In an unbiased genetic screen for mutations that activate cysteine dioxygenase (cdo-1) in the nematode C. elegans, we isolated loss-of-function mutations in rhy-1 and egl-9, which encode proteins that negatively regulate the stability or activity of the oxygen-sensing hypoxia inducible transcription factor (hif-1). EGL-9 and HIF-1 are core members of the conserved eukaryotic hypoxia response. However, we demonstrate that the mechanism of HIF-1-mediated induction of cdo-1 is largely independent of EGL-9 prolyl hydroxylase activity and the von Hippel-Lindau E3 ubiquitin ligase, the classical hypoxia signaling pathway components. We demonstrate that C. elegans cdo-1 is transcriptionally activated by high levels of cysteine and hif-1. hif-1-dependent activation of cdo-1 occurs downstream of an H2S-sensing pathway that includes rhy-1, cysl-1, and egl-9. cdo-1 transcription is primarily activated in the hypodermis where it is also sufficient to drive sulfur amino acid metabolism. Thus, the regulation of cdo-1 by hif-1 reveals a negative feedback loop that maintains cysteine homeostasis. High levels of cysteine stimulate the production of an H2S signal. H2S then acts through the rhy-1/cysl-1/egl-9 signaling pathway to increase HIF-1-mediated transcription of cdo-1, promoting degradation of cysteine via CDO-1.
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Affiliation(s)
- Kurt Warnhoff
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD 57104, USA
- Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57105 USA
| | - Sushila Bhattacharya
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Jennifer Snoozy
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Peter C. Breen
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Gary Ruvkun
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
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8
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Maushe D, Ogi V, Divakaran K, Verdecia Mogena AM, Himmighofen PA, Machado RAR, Towbin BD, Ehlers RU, Molina C, Parisod C, Maud Robert CA. Stress tolerance in entomopathogenic nematodes: Engineering superior nematodes for precision agriculture. J Invertebr Pathol 2023:107953. [PMID: 37336478 DOI: 10.1016/j.jip.2023.107953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 06/13/2023] [Accepted: 06/16/2023] [Indexed: 06/21/2023]
Abstract
Entomopathogenic nematodes (EPNs) are soil-dwelling parasitic roundworms commonly used as biocontrol agents of insect pests in agriculture. EPN dauer juveniles locate and infect a host in which they will grow and multiply until resource depletion. During their free-living stage, EPNs face a series of internal and environmental stresses. Their ability to overcome these challenges is crucial to determine their infection success and survival. In this review, we provide a comprehensive overview of EPN response to stresses associated with starvation, low/elevated temperatures, desiccation, osmotic stress, hypoxia, and ultra-violet light. We further report EPN defense strategies to cope with biotic stressors such as viruses, bacteria, fungi, and predatory insects. By comparing the genetic and biochemical basis of these strategies to the nematode model Caenorhabditis elegans, we provide new avenues and targets to select and engineer precision nematodes adapted to specific field conditions.
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Affiliation(s)
- Dorothy Maushe
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland
| | - Vera Ogi
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland
| | - Keerthi Divakaran
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland
| | | | - Paul Anton Himmighofen
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland
| | - Ricardo A R Machado
- Institute of Biology, University of Neuchâtel, Rue Emile Argand 11, CH-2000 Neuchâtel, Switzerland
| | - Benjamin Daniel Towbin
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012 Bern, Switzerland
| | - Ralf-Udo Ehlers
- e- nema GmbH, Klausdorfer Str. 28-36, DE-24223 Schwentinental, Germany
| | - Carlos Molina
- e- nema GmbH, Klausdorfer Str. 28-36, DE-24223 Schwentinental, Germany
| | - Christian Parisod
- Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
| | - Christelle Aurélie Maud Robert
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland; Oeschger Centre for Climate Change Research, University of Bern, Hochschulstrasse 4, CH-3012 Bern, Switzerland.
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Legionella pneumophila and Free-Living Nematodes: Environmental Co-Occurrence and Trophic Link. Microorganisms 2023; 11:microorganisms11030738. [PMID: 36985310 PMCID: PMC10056204 DOI: 10.3390/microorganisms11030738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/03/2023] [Accepted: 03/09/2023] [Indexed: 03/16/2023] Open
Abstract
Free-living nematodes harbor and disseminate various soil-borne bacterial pathogens. Whether they function as vectors or environmental reservoirs for the aquatic L. pneumophila, the causative agent of Legionnaires’ disease, is unknown. A survey screening of biofilms of natural (swimming lakes) and technical (cooling towers) water habitats in Germany revealed that nematodes can act as potential reservoirs, vectors or grazers of L. pneumophila in cooling towers. Consequently, the nematode species Plectus similis and L. pneumophila were isolated from the same cooling tower biofilm and taken into a monoxenic culture. Using pharyngeal pumping assays, potential feeding relationships between P. similis and different L. pneumophila strains and mutants were examined and compared with Plectus sp., a species isolated from a L. pneumophila-positive thermal source biofilm. The assays showed that bacterial suspensions and supernatants of the L. pneumophila cooling tower isolate KV02 decreased pumping rate and feeding activity in nematodes. However, assays investigating the hypothesized negative impact of Legionella’s major secretory protein ProA on pumping rate revealed opposite effects on nematodes, which points to a species-specific response to ProA. To extend the food chain by a further trophic level, Acanthamoebae castellanii infected with L. pneumphila KV02 were offered to nematodes. The pumping rates of P. similis increased when fed with L. pneumophila-infected A. castellanii, while Plectus sp. pumping rates were similar when fed either infected or non-infected A. castellanii. This study revealed that cooling towers are the main water bodies where L. pneumophila and free-living nematodes coexist and is the first step in elucidating the trophic links between coexisting taxa from that habitat. Investigating the Legionella–nematode–amoebae interactions underlined the importance of amoebae as reservoirs and transmission vehicles of the pathogen for nematode predators.
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10
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Juxtaposing Caenorhabditis elegans-Pathogenic Mould Model with Other Models; How Reliable Is This Nematode Model? A Mini Review. Curr Microbiol 2023; 80:105. [PMID: 36790616 DOI: 10.1007/s00284-023-03209-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 02/01/2023] [Indexed: 02/16/2023]
Abstract
The application of Caenorhabditis elegans as a pathogenic model has spanned decades. Its use for pathogenic mould modeling has been attracting some attention lately, though not without some reservations. Several studies have shown C. elegans to be a reliable model for evaluating moulds' virulence factors and patterns as well as for screening the pathogenicity of mutant strains alongside their parental/wild type and revertant/complementary strains. There is a very high degree of reported similarities between the virulence patterns demonstrated in C. elegans and those of other invertebrate and vertebrate models. We have here presented several works in which this nematode model was adopted for virulence evaluation, and other comparative research in which virulence in C. elegans model were juxtaposed with other models. We have further presented possible reasons why there might have been variations of virulence in a few cases, thereby validating C. elegans to be an effective and reliable tool in the study of pathogenic moulds.
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11
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Peng H, Bai H, Pan Y, Li J, Pei Z, Liao Y, Wu C, Li C, Tao L, Zhong S, Ma C, Chen Z, Li X, Gong Y, Wang L, Li F. Immunological pathogenesis of Bovine E. coli infection in a model of C. elegans. BMC Microbiol 2022; 22:311. [PMID: 36539715 PMCID: PMC9764636 DOI: 10.1186/s12866-022-02733-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 09/06/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Cattle industry is critical for China's livestock industry, whereas E. coli infection and relevant diseases could lead huge economic loss. Traditional mammalian models would be costly, time consuming and complicated to study pathological changes of bovine E. coli. There is an urgent need for a simple but efficient animal model to quantitatively evaluate the pathological changes of bovine-derived E. coli in vivo. Caenorhabditis elegans (C. elegans) has a broad host range of diverse E. coli strains with advantages, including a short life cycle, a simple structure, a transparent body which is easily visualized, a well-studied genetic map, an intrinsic immune system which is conservable with more complicated mammalians. RESULTS Here, we considered that O126 was the dominant serotype, and a total of 19 virulence factors were identified from 41 common E. coli virulence factors. Different E. coli strains with diverse pathogenicity strengths were tested in C. elegans in E. coli with higher pathogenicity (EC3/10), Nsy-1, Sek-1 and Pmk-1 of the p38 MAPK signaling pathway cascade and the expression of the antimicrobial peptides Abf-3 and Clec-60 were significantly up-regulated comparing with other groups. E. coli with lower pathogenicity (EC5/13) only activated the expression of Nsy-1 and Sek-1 genes in the p38 MAPK signaling pathway, Additionally, both groups of E. coli strains caused significant upregulation of the antimicrobial peptide Spp-1. CONCLUSION Thirteen E. coli strains showed diverse pathogenicity in nematodes and the detection rate of virulence factors did not corresponding to the virulence in nematodes, indicating complex pathogenicity mechanisms. We approved that C. elegans is a fast and convenient detection model for pathogenic bacteria virulence examinations.
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Affiliation(s)
- Hao Peng
- grid.418337.aGuangxi Key Laboratory of Veterinary Biotechnology, Guangxi Veterinary Research Institute, Nanning, 530001 China
| | - Huili Bai
- grid.418337.aGuangxi Key Laboratory of Veterinary Biotechnology, Guangxi Veterinary Research Institute, Nanning, 530001 China
| | - Yan Pan
- Guangxi Agricultural Vocational University, Nanning, China
| | - Jun Li
- grid.418337.aGuangxi Key Laboratory of Veterinary Biotechnology, Guangxi Veterinary Research Institute, Nanning, 530001 China
| | - Zhe Pei
- grid.254250.40000 0001 2264 7145The City College of New York, New York, USA
| | - Yuying Liao
- grid.418337.aGuangxi Key Laboratory of Veterinary Biotechnology, Guangxi Veterinary Research Institute, Nanning, 530001 China
| | - Cuilan Wu
- grid.418337.aGuangxi Key Laboratory of Veterinary Biotechnology, Guangxi Veterinary Research Institute, Nanning, 530001 China
| | - Changting Li
- grid.418337.aGuangxi Key Laboratory of Veterinary Biotechnology, Guangxi Veterinary Research Institute, Nanning, 530001 China
| | - Li Tao
- grid.418337.aGuangxi Key Laboratory of Veterinary Biotechnology, Guangxi Veterinary Research Institute, Nanning, 530001 China
| | - Shuhong Zhong
- grid.418337.aGuangxi Key Laboratory of Veterinary Biotechnology, Guangxi Veterinary Research Institute, Nanning, 530001 China
| | - Chunxia Ma
- grid.418337.aGuangxi Key Laboratory of Veterinary Biotechnology, Guangxi Veterinary Research Institute, Nanning, 530001 China
| | - Zhongwei Chen
- grid.418337.aGuangxi Key Laboratory of Veterinary Biotechnology, Guangxi Veterinary Research Institute, Nanning, 530001 China
| | - Xiaoning Li
- grid.418337.aGuangxi Key Laboratory of Veterinary Biotechnology, Guangxi Veterinary Research Institute, Nanning, 530001 China
| | - Yu Gong
- Animal Science and Technology Station of Guizhou, Guiyang, China
| | - Leping Wang
- grid.418337.aGuangxi Key Laboratory of Veterinary Biotechnology, Guangxi Veterinary Research Institute, Nanning, 530001 China
| | - Fengsheng Li
- grid.418337.aGuangxi Key Laboratory of Veterinary Biotechnology, Guangxi Veterinary Research Institute, Nanning, 530001 China
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12
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Ambreetha S, Marimuthu P, Mathee K, Balachandar D. Plant-associated Pseudomonas aeruginosa strains harbour multiple virulence traits critical for human infection. J Med Microbiol 2022; 71. [PMID: 35947528 DOI: 10.1099/jmm.0.001493] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Introduction. Pseudomonas aeruginosa causes fatal infections in immunocompromised individuals and patients with pulmonary disorders.Gap Statement. Agricultural ecosystems are the vast reservoirs of this dreaded pathogen. However, there are limited attempts to analyse the pathogenicity of P. aeruginosa strains associated with edible plants.Aim. This study aims to (i) elucidate the virulence attributes of P. aeruginosa strains isolated from the rhizosphere and endophytic niches of cucumber, tomato, eggplant and chili;and (ii) compare these phenotypes with that of previously characterized clinical isolates.Methodology. Crystal-violet microtitre assay, swarm plate experiment, gravimetric quantification and sheep blood lysis were performed to estimate the biofilm formation, swarming motility, rhamnolipid production and haemolytic activity, respectively, of P. aeruginosa strains. In addition, their pathogenicity was also assessed based on their ability to antagonize plant pathogens (Xanthomonas oryzae, Pythium aphanidermatum, Rhizoctonia solani and Fusarium oxysporum) and kill a select nematode (Caenorhabditis elegans).Results. Nearly 80 % of the plant-associated strains produced rhamnolipid and exhibited at least one type of lytic activity (haemolysis, proteolysis and lipolysis). Almost 50 % of these strains formed significant levels of biofilm and exhibited swarming motility. The agricultural strains showed significantly higher and lower virulence against the bacterial and fungal pathogens, respectively, compared to the clinical strains. In C. elegans, a maximum of 40 and 100% mortality were induced by the agricultural and clinical strains, respectively.Conclusion. This investigation shows that P. aeruginosa in edible plants isolated directly from the farm express virulence and pathogenicity. Furthermore, clinical and agricultural P. aeruginosa strains antagonized the tested fungal phytopathogens, Pythium aphanidermatum, Rhizoctonia solani and Fusarium oxysporum. Thus, we recommend using these fungi as simple eukaryotic model systems to test P. aeruginosa pathogenicity.
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Affiliation(s)
- Sakthivel Ambreetha
- Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India.,Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, USA
| | - Ponnusamy Marimuthu
- Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
| | - Kalai Mathee
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, USA.,Biomolecular Sciences Institute, Florida International University, Miami, Florida, USA
| | - Dananjeyan Balachandar
- Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
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Ali M, Gu T, Yu X, Bashir A, Wang Z, Sun X, Ashraf NM, Li L. Identification of the Genes of the Plant Pathogen Pseudomonas syringae MB03 Required for the Nematicidal Activity Against Caenorhabditis elegans Through an Integrated Approach. Front Microbiol 2022; 13:826962. [PMID: 35356513 PMCID: PMC8959697 DOI: 10.3389/fmicb.2022.826962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/11/2022] [Indexed: 01/04/2023] Open
Abstract
Nematicidal potential of the common plant pathogen Pseudomonas syringae has been recently identified against Caenorhabditis elegans. The current study was designed to investigate the detailed genetic mechanism of the bacterial pathogenicity by applying comparative genomics, transcriptomics, mutant library screening, and protein expression. Results showed that P. syringae strain MB03 could kill C. elegans in the liquid assay by gut colonization. The genome of P. syringae MB03 was sequenced and comparative analysis including multi locus sequence typing, and genome-to-genome distance placed MB03 in phylogroup II of P. syringae. Furthermore, comparative genomics of MB03 with nematicidal strains of Pseudomonas aeruginosa (PAO1 and PA14) predicted 115 potential virulence factors in MB03. However, genes for previously reported nematicidal metabolites, such as phenazine, pyochelin, and pyrrolnitrin, were found absent in the MB03 genome. Transcriptomics analysis showed that the growth phase of the pathogen considerably affected the expression of virulence factors, as genes for the flagellum, glutamate ABC transporter, phoP/phoQ, fleS/fleR, type VI secretion system, and serralysin were highly up-regulated when stationary phase MB03 cells interacted with C. elegans. Additionally, screening of a transposon insertion mutant library led to the identification of other nematicidal genes such as acnA, gltP, oprD, and zapE. Finally, the nematicidal activity of selected proteins was confirmed by heterologous expression in Escherichia coli.
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Affiliation(s)
- Muhammad Ali
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Department of Biotechnology, COMSATS University Islamabad, Abbottabad, Pakistan
| | - Tong Gu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Xun Yu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Anum Bashir
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Zhiyong Wang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Xiaowen Sun
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Naeem Mahmood Ashraf
- Department of Biochemistry and Biotechnology, University of Gujrat, Gujrat, Pakistan
| | - Lin Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- *Correspondence: Lin Li,
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14
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Rangseekaew P, Barros-Rodríguez A, Pathom-aree W, Manzanera M. Plant Beneficial Deep-Sea Actinobacterium, Dermacoccus abyssi MT1.1T Promote Growth of Tomato (Solanum lycopersicum) under Salinity Stress. BIOLOGY 2022; 11:biology11020191. [PMID: 35205058 PMCID: PMC8869415 DOI: 10.3390/biology11020191] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 01/24/2022] [Accepted: 01/24/2022] [Indexed: 12/23/2022]
Abstract
Simple Summary Salt stress is an important environmental problem that negatively affects agricultural and food production in the world. Currently, the use of plant beneficial bacteria for plant growth promotion is attractive due to the demand for eco-friendly and sustainable agriculture. In this study, salt tolerant deep-sea actinobacterium, Dermacoccus abyssi MT1.1T was investigated plant growth promotion and salt stress mitigation in tomato seedlings. In addition, D. abyssi MT1.1T whole genome was analyzed for plant growth promoting traits and genes related to salt stress alleviation in plants. We also evaluated the biosafety of this strain on human health and organisms in the environment. Our results highlight that the inoculation of D. abyssi MT1.1T could reduce the negative effects of salt stress in tomato seedlings by growth improvement, total soluble sugars accumulation and hydrogen peroxide reduction. Moreover, this strain could survive and colonize tomato roots. Biosafety testing and genome analysis of D. abyssi MT1.1T showed no pathogenicity risk. In conclusion, we provide supporting evidence on the potential of D. abyssi MT1.1T as a safe strain for use in plant growth promotion under salt stress. Abstract Salt stress is a serious agricultural problem threatens plant growth and development resulted in productivity loss and global food security concerns. Salt tolerant plant growth promoting actinobacteria, especially deep-sea actinobacteria are an alternative strategy to mitigate deleterious effects of salt stress. In this study, we aimed to investigate the potential of deep-sea Dermacoccus abyssi MT1.1T to mitigate salt stress in tomato seedlings and identified genes related to plant growth promotion and salt stress mitigation. D. abyssi MT1.1T exhibited plant growth promoting traits namely indole-3-acetic acid (IAA) and siderophore production and phosphate solubilization under 0, 150, 300, and 450 mM NaCl in vitro. Inoculation of D. abyssi MT1.1T improved tomato seedlings growth in terms of shoot length and dry weight compared with non-inoculated seedlings under 150 mM NaCl. In addition, increased total soluble sugar and total chlorophyll content and decreased hydrogen peroxide content were observed in tomato inoculated with D. abyssi MT1.1T. These results suggested that this strain mitigated salt stress in tomatoes via osmoregulation by accumulation of soluble sugars and H2O2 scavenging activity. Genome analysis data supported plant growth promoting and salt stress mitigation potential of D. abyssi MT1.1T. Survival and colonization of D. abyssi MT1.1T were observed in roots of inoculated tomato seedlings. Biosafety testing on D. abyssi MT1.1T and in silico analysis of its whole genome sequence revealed no evidence of its pathogenicity. Our results demonstrate the potential of deep-sea D. abyssi MT1.1T to mitigate salt stress in tomato seedlings and as a candidate of eco-friendly bio-inoculants for sustainable agriculture.
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Affiliation(s)
- Pharada Rangseekaew
- Doctor of Philosophy Program in Applied Microbiology (International Program) in Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand;
- Graduate School, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Adoración Barros-Rodríguez
- Department of Microbiology, Institute for Water Research, University of Granada, 18071 Granada, Spain; (A.B.-R.); (M.M.)
| | - Wasu Pathom-aree
- Research Center in Bioresources for Agriculture, Industry and Medicine, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
- Correspondence: ; Tel.: +66-53943346-48
| | - Maximino Manzanera
- Department of Microbiology, Institute for Water Research, University of Granada, 18071 Granada, Spain; (A.B.-R.); (M.M.)
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15
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Mack HID, Kremer J, Albertini E, Mack EKM, Jansen-Dürr P. Regulation of fatty acid desaturase- and immunity gene-expression by mbk-1/DYRK1A in Caenorhabditis elegans. BMC Genomics 2022; 23:25. [PMID: 34983389 PMCID: PMC8729107 DOI: 10.1186/s12864-021-08176-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 11/08/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In the nematode Caenorhabditis elegans, longevity in response to germline ablation, but not in response to reduced insulin/IGF1-like signaling, is strongly dependent on the conserved protein kinase minibrain-related kinase 1 (MBK-1). In humans, the MBK-1 ortholog DYRK1A is associated with a variety of disorders, most prominently with neurological defects observed in Down syndrome. To better understand mbk-1's physiological roles and their dependence on genetic background, we analyzed the influence of mbk-1 loss on the transcriptomes of wildtype and long-lived, germline-deficient or insulin-receptor defective, C. elegans strains by RNA-sequencing. RESULTS mbk-1 loss elicited global changes in transcription that were less pronounced in insulin-receptor mutant than in germline-deficient or wildtype C. elegans. Irrespective of genetic background, mbk-1 regulated genes were enriched for functions in biological processes related to organic acid metabolism and pathogen defense. qPCR-studies confirmed mbk-1 dependent induction of all three C. elegans Δ9-fatty acid desaturases, fat-5, fat-6 and fat-7, in wildtype, germline-deficient and insulin-receptor mutant strains. Conversely, mbk-1 dependent expression patterns of selected pathogen resistance genes, including asp-12, dod-24 and drd-50, differed across the genetic backgrounds examined. Finally, cth-1 and cysl-2, two genes which connect pathogen resistance to the metabolism of the gaseous messenger and lifespan regulator hydrogen sulfide (H2S), were commonly suppressed by mbk-1 loss only in wildtype and germline-deficient, but not in insulin-receptor mutant C. elegans. CONCLUSION Our work reveals previously unknown roles of C. elegans mbk-1 in the regulation of fatty acid desaturase- and H2S metabolic-genes. These roles are only partially dependent on genetic background. Considering the particular importance of fatty acid desaturation and H2S for longevity of germline-deficient C. elegans, we propose that these processes at least in part account for the previous observation that mbk-1 preferentially regulates lifespan in these worms.
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Affiliation(s)
- Hildegard I D Mack
- Institute for Biomedical Aging Research, University of Innsbruck, Rennweg 10, 6020, Innsbruck, Austria.
| | - Jennifer Kremer
- Department of Hematology, Oncology and Immunology, Philipps-University Marburg, and University Hospital Giessen and Marburg, Baldingerstrasse, 35032, Marburg, Germany
| | - Eva Albertini
- Institute for Biomedical Aging Research, University of Innsbruck, Rennweg 10, 6020, Innsbruck, Austria
| | - Elisabeth K M Mack
- Department of Hematology, Oncology and Immunology, Philipps-University Marburg, and University Hospital Giessen and Marburg, Baldingerstrasse, 35032, Marburg, Germany
| | - Pidder Jansen-Dürr
- Institute for Biomedical Aging Research, University of Innsbruck, Rennweg 10, 6020, Innsbruck, Austria.
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16
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Miranda SW, Asfahl KL, Dandekar AA, Greenberg EP. Pseudomonas aeruginosa Quorum Sensing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:95-115. [PMID: 36258070 PMCID: PMC9942581 DOI: 10.1007/978-3-031-08491-1_4] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Pseudomonas aeruginosa, like many bacteria, uses chemical signals to communicate between cells in a process called quorum sensing (QS). QS allows groups of bacteria to sense population density and, in response to changing cell densities, to coordinate behaviors. The P. aeruginosa QS system consists of two complete circuits that involve acyl-homoserine lactone signals and a third system that uses quinolone signals. Together, these three QS circuits regulate the expression of hundreds of genes, many of which code for virulence factors. P. aeruginosa has become a model for studying the molecular biology of QS and the ecology and evolution of group behaviors in bacteria. In this chapter, we recount the history of discovery of QS systems in P. aeruginosa, discuss how QS relates to virulence and the ecology of this bacterium, and explore strategies to inhibit QS. Finally, we discuss future directions for research in P. aeruginosa QS.
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Affiliation(s)
| | - Kyle L Asfahl
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA, USA
| | - Ajai A Dandekar
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA, USA
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - E P Greenberg
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA, USA.
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17
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Insights from C. elegans into Microsporidia Biology and Host-Pathogen Relationships. EXPERIENTIA SUPPLEMENTUM 2022; 114:115-136. [PMID: 35544001 PMCID: PMC9208714 DOI: 10.1007/978-3-030-93306-7_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Microsporidia are poorly understood, ubiquitous eukaryotic parasites that are completely dependent on their hosts for replication. With the discovery of microsporidia species naturally infecting the genetically tractable transparent nematode C. elegans, this host has been used to explore multiple areas of microsporidia biology. Here we review results about microsporidia infections in C. elegans, which began with the discovery of the intestinal-infecting species Nematocida parisii. Recent findings include new species identification in the Nematocida genus, with more intestinal-infecting species, and also a species with broader tissue tropism, the epidermal and muscle-infecting species Nematocida displodere. This species has a longer polar tube infection apparatus, which may enable its wider tissue range. After invasion, multiple Nematocida species appear to fuse host cells, which likely promotes their dissemination within host organs. Localized proteomics identified Nematocida proteins that have direct contact with the C. elegans intestinal cytosol and nucleus, and many of these host-exposed proteins belong to expanded, species-specific gene families. On the host side, forward genetic screens have identified regulators of the Intracellular Pathogen Response (IPR), which is a transcriptional response induced by both microsporidia and the Orsay virus, which is also a natural, obligate intracellular pathogen of the C. elegans intestine. The IPR constitutes a novel immune/stress response that promotes resistance against microsporidia, virus, and heat shock. Overall, the Nematocida/C. elegans system has provided insights about strategies for microsporidia pathogenesis, as well as innate defense pathways against these parasites.
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18
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Bashir A, Sun Y, Yu X, Sun X, Li L. Nematicidal effects of 2-methyl-aconitate isomerase from the phytopathogen Pseudomonas syringae MB03 on the model nematode Caenorhabditis elegans. J Invertebr Pathol 2021; 185:107669. [PMID: 34560108 DOI: 10.1016/j.jip.2021.107669] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 09/14/2021] [Accepted: 09/15/2021] [Indexed: 10/24/2022]
Abstract
The pathogenicity of a common phytopathogenic bacterium, Pseudomonas syringae, against animal model hosts, such as mice and Caenorhabditis elegans, has been recently revealed. However, most of the virulence determinants associated with pathogenesis remain elusive. In the current study, we performed predictive analysis of virulence factors against C. elegans in the genome of the wild-type P. syringae strain MB03. Nine predicted nematicidal proteins were expressed and purified in recombinant Escherichia coli strains and were evaluated to define their toxicity against C. elegans in liquid killing assays. Next, we focused on one essential 2-methyl citrate cycle protein, PrpF03, which showed the highest lethal activity against C. elegans compared to the other tested proteins with a half lethal concentration (LC50) of 155.3 (123.4-176.6) µg mL-1 and a half lethal time (LT50) of 3.72 (1.64-4.85) days. Purified PrpF03 also caused adverse effects on the brood size, growth, and motility of C. elegans. Moreover, the PrpF03 protein exhibited pathological activity towards the intestinal tract of C. elegans. We surmise that the PrpF03 protein functions as a virulence factor when it blocks the average circulation of the 2-methyl citrate cycle of C. elegans by accumulating 2-methyl citrate in the gut of C. elegans, which damages and restrains the growth of intestinal tissues that ultimately kill C. elegans. The discovery of specific nematicidal activities of PrpF03 provides a better understanding of the mechanisms of phytopathogenic P. syringae against nematodes and could aid in developing nematode pest-controlling agents in agriculture.
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Affiliation(s)
- Anum Bashir
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yu Sun
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xun Yu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xiaowen Sun
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Lin Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
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Fraser-Pitt DJ, Dolan SK, Toledo-Aparicio D, Hunt JG, Smith DW, Lacy-Roberts N, Nupe Hewage PS, Stoyanova TN, Manson E, McClean K, Inglis NF, Mercer DK, O’Neil DA. Cysteamine Inhibits Glycine Utilisation and Disrupts Virulence in Pseudomonas aeruginosa. Front Cell Infect Microbiol 2021; 11:718213. [PMID: 34631600 PMCID: PMC8494450 DOI: 10.3389/fcimb.2021.718213] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/11/2021] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas aeruginosa is a major opportunistic human pathogen which employs a myriad of virulence factors. In people with cystic fibrosis (CF) P. aeruginosa frequently colonises the lungs and becomes a chronic infection that evolves to become less virulent over time, but often adapts to favour persistence in the host with alginate-producing mucoid, slow-growing, and antibiotic resistant phenotypes emerging. Cysteamine is an endogenous aminothiol which has been shown to prevent biofilm formation, reduce phenazine production, and potentiate antibiotic activity against P. aeruginosa, and has been investigated in clinical trials as an adjunct therapy for pulmonary exacerbations of CF. Here we demonstrate (for the first time in a prokaryote) that cysteamine prevents glycine utilisation by P. aeruginosa in common with previously reported activity blocking the glycine cleavage system in human cells. Despite the clear inhibition of glycine metabolism, cysteamine also inhibits hydrogen cyanide (HCN) production by P. aeruginosa, suggesting a direct interference in the regulation of virulence factor synthesis. Cysteamine impaired chemotaxis, lowered pyocyanin, pyoverdine and exopolysaccharide production, and reduced the toxicity of P. aeruginosa secreted factors in a Galleria mellonella infection model. Thus, cysteamine has additional potent anti-virulence properties targeting P. aeruginosa, further supporting its therapeutic potential in CF and other infections.
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Affiliation(s)
| | - Stephen K. Dolan
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | | | | | | | | | - Piumi Sara Nupe Hewage
- School of Pharmacy and Life Sciences, Robert Gordon University, Aberdeen, United Kingdom
| | - Teodora N. Stoyanova
- School of Pharmacy and Life Sciences, Robert Gordon University, Aberdeen, United Kingdom
| | - Erin Manson
- College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Kevin McClean
- Proteomics Facility Services, Moredun Research Institute, Penicuik, United Kingdom
| | - Neil F. Inglis
- Proteomics Facility Services, Moredun Research Institute, Penicuik, United Kingdom
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Deep-Sea Actinobacteria Mitigate Salinity Stress in Tomato Seedlings and Their Biosafety Testing. PLANTS 2021; 10:plants10081687. [PMID: 34451732 PMCID: PMC8401925 DOI: 10.3390/plants10081687] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/04/2021] [Accepted: 08/11/2021] [Indexed: 12/13/2022]
Abstract
Soil salinity is an enormous problem affecting global agricultural productivity. Deep-sea actinobacteria are interesting due to their salt tolerance mechanisms. In the present study, we aim to determine the ability of deep-sea Dermacoccus (D. barathri MT2.1T and D. profundi MT2.2T) to promote tomato seedlings under 150 mM NaCl compared with the terrestrial strain D. nishinomiyaensis DSM20448T. All strains exhibit in vitro plant growth-promoting traits of indole-3-acetic acid production, phosphate solubilization, and siderophore production. Tomato seedlings inoculated with D. barathri MT2.1T showed higher growth parameters (shoot and root length, dry weight, and chlorophyll content) than non-inoculated tomato and the terrestrial strain under 150 mM NaCl. In addition, hydrogen peroxide (H2O2) in leaves of tomatoes inoculated with deep-sea Dermacoccus was lower than the control seedlings. This observation suggested that deep-sea Dermacoccus mitigated salt stress by reducing oxidative stress caused by hydrogen peroxide. D. barathri MT2.1T showed no harmful effects on Caenorhabditis elegans, Daphnia magna, Eisenia foetida, and Escherichia coli MC4100 in biosafety tests. This evidence suggests that D. barathri MT2.1T would be safe for use in the environment. Our results highlight the potential of deep-sea Dermacoccus as a plant growth promoter for tomatoes under salinity stress.
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21
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Zuhra K, Szabo C. The two faces of cyanide: an environmental toxin and a potential novel mammalian gasotransmitter. FEBS J 2021; 289:2481-2515. [PMID: 34297873 PMCID: PMC9291117 DOI: 10.1111/febs.16135] [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] [Received: 05/21/2021] [Revised: 07/15/2021] [Accepted: 07/22/2021] [Indexed: 12/16/2022]
Abstract
Cyanide is traditionally viewed as a cytotoxic agent, with its primary mode of action being the inhibition of mitochondrial Complex IV (cytochrome c oxidase). However, recent studies demonstrate that the effect of cyanide on Complex IV in various mammalian cells is biphasic: in lower concentrations (nanomolar to low micromolar) cyanide stimulates Complex IV activity, increases ATP production and accelerates cell proliferation, while at higher concentrations (high micromolar to low millimolar) it produces the previously known (‘classic’) toxic effects. The first part of the article describes the cytotoxic actions of cyanide in the context of environmental toxicology, and highlights pathophysiological conditions (e.g., cystic fibrosis with Pseudomonas colonization) where bacterially produced cyanide exerts deleterious effects to the host. The second part of the article summarizes the mammalian sources of cyanide production and overviews the emerging concept that mammalian cells may produce cyanide, in low concentrations, to serve biological regulatory roles. Cyanide fulfills many of the general criteria as a ‘classical’ mammalian gasotransmitter and shares some common features with the current members of this class: nitric oxide, carbon monoxide, and hydrogen sulfide.
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Affiliation(s)
- Karim Zuhra
- Chair of Pharmacology, Section of Medicine, University of Fribourg, Switzerland
| | - Csaba Szabo
- Chair of Pharmacology, Section of Medicine, University of Fribourg, Switzerland
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22
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Feng D, Zhai Z, Shao Z, Zhang Y, Powell-Coffman JA. Crosstalk in oxygen homeostasis networks: SKN-1/NRF inhibits the HIF-1 hypoxia-inducible factor in Caenorhabditis elegans. PLoS One 2021; 16:e0249103. [PMID: 34242227 PMCID: PMC8270126 DOI: 10.1371/journal.pone.0249103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/24/2021] [Indexed: 11/30/2022] Open
Abstract
During development, homeostasis, and disease, organisms must balance responses that allow adaptation to low oxygen (hypoxia) with those that protect cells from oxidative stress. The evolutionarily conserved hypoxia-inducible factors are central to these processes, as they orchestrate transcriptional responses to oxygen deprivation. Here, we employ genetic strategies in C. elegans to identify stress-responsive genes and pathways that modulate the HIF-1 hypoxia-inducible factor and facilitate oxygen homeostasis. Through a genome-wide RNAi screen, we show that RNAi-mediated mitochondrial or proteasomal dysfunction increases the expression of hypoxia-responsive reporter Pnhr-57::GFP in C. elegans. Interestingly, only a subset of these effects requires hif-1. Of particular importance, we found that skn-1 RNAi increases the expression of hypoxia-responsive reporter Pnhr-57::GFP and elevates HIF-1 protein levels. The SKN-1/NRF transcription factor has been shown to promote oxidative stress resistance. We present evidence that the crosstalk between HIF-1 and SKN-1 is mediated by EGL-9, the prolyl hydroxylase that targets HIF-1 for oxygen-dependent degradation. Treatment that induces SKN-1, such as heat or gsk-3 RNAi, increases expression of a Pegl-9::GFP reporter, and this effect requires skn-1 function and a putative SKN-1 binding site in egl-9 regulatory sequences. Collectively, these data support a model in which SKN-1 promotes egl-9 transcription, thereby inhibiting HIF-1. We propose that this interaction enables animals to adapt quickly to changes in cellular oxygenation and to better survive accompanying oxidative stress.
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Affiliation(s)
- Dingxia Feng
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
| | - Zhiwei Zhai
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
| | - Zhiyong Shao
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
| | - Yi Zhang
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
| | - Jo Anne Powell-Coffman
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, United States of America
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Cheng X, Pu L, Fu S, Xia A, Huang S, Ni L, Xing X, Yang S, Jin F. Engineering Gac/Rsm Signaling Cascade for Optogenetic Induction of the Pathogenicity Switch in Pseudomonas aeruginosa. ACS Synth Biol 2021; 10:1520-1530. [PMID: 34076414 DOI: 10.1021/acssynbio.1c00075] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Bacterial pathogens operate by tightly controlling the pathogenicity to facilitate invasion and survival in host. While small molecule inducers can be designed to modulate pathogenicity to perform studies of pathogen-host interaction, these approaches, due to the diffusion property of chemicals, may have unintended, or pleiotropic effects that can impose limitations on their use. By contrast, light provides superior spatial and temporal resolution. Here, using optogenetics we reengineered GacS of the opportunistic pathogen Pseudomonas aeruginosa, signal transduction protein of the global regulatory Gac/Rsm cascade which is of central importance for the regulation of infection factors. The resultant protein (termed YGS24) displayed significant light-dependent activity of GacS kinases in Pseudomonas aeruginosa. When introduced in the Caenorhabditis elegans host systems, YGS24 stimulated the pathogenicity of the Pseudomonas aeruginosa strain PAO1 in a brain-heart infusion and of another strain, PA14, in slow killing media progressively upon blue-light exposure. This optogenetic system provides an accessible way to spatiotemporally control bacterial pathogenicity in defined hosts, even specific tissues, to develop new pathogenesis systems, which may in turn expedite development of innovative therapeutics.
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Affiliation(s)
- Xinyi Cheng
- Hefei National Laboratory for Physical Sciences at the Microscale; Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Lu Pu
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Shengwei Fu
- Hefei National Laboratory for Physical Sciences at the Microscale; Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Aiguo Xia
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Shuqiang Huang
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Lei Ni
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Xiaochen Xing
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Shuai Yang
- Hefei National Laboratory for Physical Sciences at the Microscale; Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Fan Jin
- Hefei National Laboratory for Physical Sciences at the Microscale; Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
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24
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Immunomodulatory effect of pentagalloyl glucose in LPS-stimulated RAW264.7 macrophages and PAO1-induced Caenorhabditis elegans. Exp Gerontol 2021; 150:111388. [PMID: 33957261 DOI: 10.1016/j.exger.2021.111388] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 11/23/2022]
Abstract
Pentagalloyl glucose (PGG) is a valuable natural compound with an array of biological activities, but the immunomodulatory effect and mechanism have not been fully validated yet. In this study, to elucidate comprehensively the function of immunomodulation and its underlying mechanism of PGG in vitro and in vivo, two model systems were conducted, which including lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages cells and Pseudomonas aeruginosa (PAO1)-induced Caenorhabditis elegans (C. elegans). Current results showed that PGG significantly inhibited secretions of tumor necrosis factor-α (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6) and mediator nitric oxide (NO) in LPS-stimulated RAW264.7 cells. In addition, the expression of genes nitric oxide synthase (iNOS), TNF-α, IL-1β and IL-6 in LPS- stimulated RAW264.7 cells was reduced by PGG. In vivo assay showed that lifespan of PAO1-induced C. elegans was enhanced significantly by 14.1% under the pre-treatment of PGG, which was abrogated in toxin sensitive mdt-15 mutant. Similarly, the PGG showed a benefit on 41.2% significant extension longevity in C. elegans under pathogenic PA14. And the nuclear localization of DAF-16 of strain TJ356 was significantly increased in PAO1-induced C. elegans by PGG. Further, PGG modulated several signaling pathways to enhance immunomodulation in C. elegans including DBL-1, DAF-2/DAF-16, and mitogen-activated protein (MAP) kinase pathways. Furthermore, other genes involved in immunomodulatory response in C. elegans were remarkably regulated such as lys-1, lys-2, spp-18, egl-9, and hif-1. Our study suggested that PGG have potential to develop into novel immunomodulatory nutraceutical.
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25
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Gamalero E, Glick BR. The Use of Plant Growth-Promoting Bacteria to Prevent Nematode Damage to Plants. BIOLOGY 2020; 9:biology9110381. [PMID: 33171782 PMCID: PMC7695023 DOI: 10.3390/biology9110381] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 10/31/2020] [Accepted: 11/04/2020] [Indexed: 01/17/2023]
Abstract
Simple Summary It has been estimated that 100 g of bulk soil can host about 2000–4000 nematodes and this amount is increased 5-fold in the rhizosphere. A certain number of these nematodes are pathogenic for plants and cause yield and economic losses. Application of chemical nematicides is the most common method used to reduce nematode populations, but these chemicals can have a negative impact on both the environment and human health. Therefore, other more environmentally friendly methods of suppression of plant-parasitic nematodes have been proposed. Among them, the use of plant beneficial soil bacteria, behaving as biocontrol agents against nematodes, represent a potential alternative to chemicals. Abstract Plant-parasitic nematodes have been estimated to annually cause around US $173 billion in damage to plant crops worldwide. Moreover, with global climate change, it has been suggested that the damage to crops from nematodes is likely to increase in the future. Currently, a variety of potentially dangerous and toxic chemical agents are used to limit the damage to crops by plant-parasitic nematodes. As an alternative to chemicals and a more environmentally friendly means of decreasing nematode damage to plants, researchers have begun to examine the possible use of various soil bacteria, including plant growth-promoting bacteria (PGPB). Here, the current literature on some of the major mechanisms employed by these soil bacteria is examined. It is expected that within the next 5–10 years, as scientists continue to elaborate the mechanisms used by these bacteria, biocontrol soil bacteria will gradually replace the use of chemicals as nematicides.
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Affiliation(s)
- Elisa Gamalero
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, Viale T. Michel 11, 15121 Alessandria, Italy
- Correspondence: ; Tel.: +39-0131-360238
| | - Bernard R. Glick
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada;
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26
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Goswamy D, Irazoqui JE. A unifying hypothesis on the central role of reactive oxygen species in bacterial pathogenesis and host defense in C. elegans. Curr Opin Immunol 2020; 68:9-20. [PMID: 32898751 DOI: 10.1016/j.coi.2020.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/10/2020] [Accepted: 08/12/2020] [Indexed: 01/06/2023]
Abstract
During intestinal infection, microbes induce ROS by various mechanisms in C. elegans. ROS can have beneficial roles, acting as antimicrobials and as signaling molecules that activate cytoprotective pathways. Failure to maintain appropriate levels of ROS causes oxidative stress and cellular damage. This review uses the Damage Response Framework to interpret several recent observations on the relationships between infection, host response, and host damage, with a focus on mechanisms mediated by ROS. We propose a unifying hypothesis that ROS drive a collapse in proteostasis in infected C. elegans, which results in death during unresolved infection. Because the signaling pathways highlighted here are conserved in mammals, the mentioned and future studies can provide new tools of hypothesis generation in human health and disease.
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Affiliation(s)
- Debanjan Goswamy
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605, United States; Immunology and Microbiology Program, University of Massachusetts Medical School, Worcester, MA 01605, United States
| | - Javier E Irazoqui
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605, United States; Immunology and Microbiology Program, University of Massachusetts Medical School, Worcester, MA 01605, United States.
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27
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Abstract
Microbes are ubiquitous in the natural environment of Caenorhabditis elegans. Bacteria serve as a food source for C. elegans but may also cause infection in the nematode host. The sensory nervous system of C. elegans detects diverse microbial molecules, ranging from metabolites produced by broad classes of bacteria to molecules synthesized by specific strains of bacteria. Innate recognition through chemosensation of bacterial metabolites or mechanosensation of bacteria can induce immediate behavioral responses. The ingestion of nutritive or pathogenic bacteria can modulate internal states that underlie long-lasting behavioral changes. Ingestion of nutritive bacteria leads to learned attraction and exploitation of the bacterial food source. Infection, which is accompanied by activation of innate immunity, stress responses, and host damage, leads to the development of aversive behavior. The integration of a multitude of microbial sensory cues in the environment is shaped by experience and context. Genetic, chemical, and neuronal studies of C. elegans behavior in the presence of bacteria have defined neural circuits and neuromodulatory systems that shape innate and learned behavioral responses to microbial cues. These studies have revealed the profound influence that host-microbe interactions have in governing the behavior of this simple animal host.
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Affiliation(s)
- Dennis H Kim
- Division of Infectious Diseases, Boston Children's Hospital, and Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Steven W Flavell
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
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28
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Castro D, Torres M, Sampedro I, Martínez-Checa F, Torres B, Béjar V. Biological Control of Verticillium Wilt on Olive Trees by the Salt-Tolerant Strain Bacillus velezensis XT1. Microorganisms 2020; 8:E1080. [PMID: 32698452 PMCID: PMC7409040 DOI: 10.3390/microorganisms8071080] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/14/2020] [Accepted: 07/17/2020] [Indexed: 12/20/2022] Open
Abstract
Verticillium wilt, caused by the pathogen Verticillium dahliae, is extremely devastating to olive trees (Olea europea). Currently, no successful control measure is available against it. The objective of this work was to evaluate the antifungal activity of Bacillus velezensis XT1, a well-characterized salt-tolerant biocontrol strain, against the highly virulent defoliating V. dahliae V024. In vitro, strain XT1 showed to reduce fungal mycelium from 34 to 100%, depending on if the assay was conducted with the supernatant, volatile compounds, lipopeptides or whole bacterial culture. In preventive treatments, when applied directly on young olive trees, it reduced Verticillium incidence rate and percentage of severity by 54 and ~80%, respectively. It increased polyphenol oxidase (PPO) activity by 395%, indicating an enhancement of disease resistance in plant tissues, and it decreased by 20.2% the number of fungal microsclerotia in soil. In adult infected trees, palliative inoculation of strain XT1 in the soil resulted in a reduction in Verticillium symptom severity by ~63%. Strain XT1 is biosafe, stable in soil and able to colonize olive roots endophytically. All the traits described above make B. velezensis XT1 a promising alternative to be used in agriculture for the management of Verticillium wilt.
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Affiliation(s)
- David Castro
- Xtrem Biotech S.L., European Business Innovation Center, 18100 Granada, Spain; (D.C.); (B.T.)
| | - Marta Torres
- Department of Microbiology, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain; (I.S.); (F.M.-C.); (V.B.)
- Biomedical Research Center, Institute of Biotechnology, 18016 Granada, Spain
| | - Inmaculada Sampedro
- Department of Microbiology, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain; (I.S.); (F.M.-C.); (V.B.)
- Biomedical Research Center, Institute of Biotechnology, 18016 Granada, Spain
| | - Fernando Martínez-Checa
- Department of Microbiology, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain; (I.S.); (F.M.-C.); (V.B.)
- Biomedical Research Center, Institute of Biotechnology, 18016 Granada, Spain
| | - Borja Torres
- Xtrem Biotech S.L., European Business Innovation Center, 18100 Granada, Spain; (D.C.); (B.T.)
| | - Victoria Béjar
- Department of Microbiology, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain; (I.S.); (F.M.-C.); (V.B.)
- Biomedical Research Center, Institute of Biotechnology, 18016 Granada, Spain
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29
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The Nitrite Transporter Facilitates Biofilm Formation via Suppression of Nitrite Reductase and Is a New Antibiofilm Target in Pseudomonas aeruginosa. mBio 2020; 11:mBio.00878-20. [PMID: 32636243 PMCID: PMC7343986 DOI: 10.1128/mbio.00878-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial biofilms play roles in infections and avoidance of host defense mechanisms of medically important pathogens and increase the antibiotic resistance of the bacteria. Nitric oxide (NO) is reported to be involved in both biofilm formation and dispersal, which are conflicting processes. The mechanism by which NO regulates biofilm dispersal is relatively understood, but there are no reports about how NO is involved in biofilm formation. Here, by investigating the mechanism by which complestatin inhibits biofilm formation, we describe a novel mechanism for governing biofilm formation in Escherichia coli and Pseudomonas aeruginosa. Nitrite transporter is required for biofilm formation via regulation of NO levels and subsequent c-di-GMP production. Additionally, the nitrite transporter contributes more to P. aeruginosa virulence than quorum sensing. Thus, this study identifies nitrite transporters as new antibiofilm targets for future practical and therapeutic agent development. Biofilm-forming bacteria, including the Gram-negative Pseudomonas aeruginosa, cause multiple types of chronic infections and are responsible for serious health burdens in humans, animals, and plants. Nitric oxide (NO) has been shown to induce biofilm dispersal via triggering a reduction in cyclic-di-GMP levels in a variety of bacteria. However, how NO, at homeostatic levels, also facilitates biofilm formation is unknown. Here, we found that complestatin, a structural analog of vancomycin isolated from Streptomyces, inhibits P. aeruginosa biofilm formation by upregulating NO production via nitrite reductase (NIR) induction and c-di-GMP degradation via phosphodiesterase (PDE) stimulation. The complestatin protein target was identified as a nitrite transporter from a genome-wide screen using the Keio Escherichia coli knockout library and confirmed using nitrite transporter knockout and overexpression strains. We demonstrated that the nitrite transporter stimulated biofilm formation by controlled NO production via appropriate NIR suppression and subsequent diguanylate cyclase (DGC) activation, not PDE activity, and c-di-GMP production in E. coli and P. aeruginosa. Thus, this study provides a mechanism for NO-mediated biofilm formation, which was previously not understood.
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30
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Ahamefule CS, Qin Q, Odiba AS, Li S, Moneke AN, Ogbonna JC, Jin C, Wang B, Fang W. Caenorhabditis elegans-Based Aspergillus fumigatus Infection Model for Evaluating Pathogenicity and Drug Efficacy. Front Cell Infect Microbiol 2020; 10:320. [PMID: 32670897 PMCID: PMC7332887 DOI: 10.3389/fcimb.2020.00320] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/26/2020] [Indexed: 11/13/2022] Open
Abstract
Aspergillus fumigatus is the most reported causative pathogen associated with the increasing global incidences of aspergilloses, with the health of immunocompromised individuals mostly at risk. Monitoring the pathogenicity of A. fumigatus strains to identify virulence factors and evaluating the efficacy of potent active agents against this fungus in animal models are indispensable in current research effort. Caenorhabditis elegans has been successfully utilized as an infection model for bacterial and dimorphic fungal pathogens because of the advantages of being time-efficient, and less costly. However, application of this model to the filamentous fungus A. fumigatus is less investigated. In this study, we developed and optimized a stable and reliable C. elegans model for A. fumigatus infection, and demonstrated the infection process with a fluorescent strain. Virulence results of several mutant strains in our nematode model demonstrated high consistency with the already reported pathogenicity pattern in other models. Furthermore, this C. elegans-A. fumigatus infection model was optimized for evaluating the efficacy of current antifungal drugs. Interestingly, the azole drugs in nematode model prevented conidial germination to a higher extent than amphotericin B. Overall, our established C. elegans infection model for A. fumigatus has potential applications in pathogenicity evaluation, antifungal agents screening, drug efficacy evaluation as well as host-pathogen interaction studies.
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Affiliation(s)
- Chukwuemeka Samson Ahamefule
- National Engineering Research Center for Non-food Biorefinery, Guangxi Academy of Sciences, Nanning, China
- College of Life Science and Technology, Guangxi University, Nanning, China
- Department of Microbiology, University of Nigeria, Nsukka, Nigeria
| | - Qijian Qin
- National Engineering Research Center for Non-food Biorefinery, Guangxi Academy of Sciences, Nanning, China
| | - Arome Solomon Odiba
- National Engineering Research Center for Non-food Biorefinery, Guangxi Academy of Sciences, Nanning, China
- College of Life Science and Technology, Guangxi University, Nanning, China
| | - Siqiao Li
- State Key Laboratory of Non-food Biomass and Enzyme Technology, Guangxi Academy of Sciences, Nanning, China
| | - Anene N. Moneke
- Department of Microbiology, University of Nigeria, Nsukka, Nigeria
| | - James C. Ogbonna
- Department of Microbiology, University of Nigeria, Nsukka, Nigeria
| | - Cheng Jin
- National Engineering Research Center for Non-food Biorefinery, Guangxi Academy of Sciences, Nanning, China
- College of Life Science and Technology, Guangxi University, Nanning, China
| | - Bin Wang
- National Engineering Research Center for Non-food Biorefinery, Guangxi Academy of Sciences, Nanning, China
- State Key Laboratory of Non-food Biomass and Enzyme Technology, Guangxi Academy of Sciences, Nanning, China
| | - Wenxia Fang
- National Engineering Research Center for Non-food Biorefinery, Guangxi Academy of Sciences, Nanning, China
- State Key Laboratory of Non-food Biomass and Enzyme Technology, Guangxi Academy of Sciences, Nanning, China
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31
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Kruempel JCP, Miller HA, Schaller ML, Fretz A, Howington M, Sarker M, Huang S, Leiser SF. Hypoxic response regulators RHY-1 and EGL-9/PHD promote longevity through a VHL-1-independent transcriptional response. GeroScience 2020; 42:1621-1633. [PMID: 32399915 DOI: 10.1007/s11357-020-00194-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 04/15/2020] [Indexed: 12/19/2022] Open
Abstract
HIF-1-mediated adaptation to changes in oxygen availability is a critical aspect of healthy physiology. HIF is regulated by a conserved mechanism whereby EGLN/PHD family members hydroxylate HIF in an oxygen-dependent manner, targeting it for ubiquitination by Von-Hippel-Lindau (VHL) family members, leading to its proteasomal degradation. The activity of the only C. elegans PHD family member, EGL-9, is also regulated by a hydrogen sulfide sensing cysteine-synthetase-like protein, CYSL-1, which is, in turn, regulated by RHY-1/acyltransferase. Over the last decade, multiple seminal studies have established a role for the hypoxic response in regulating longevity, with mutations in vhl-1 substantially extending C. elegans lifespan through a HIF-1-dependent mechanism. However, studies on other components of the hypoxic signaling pathway that similarly stabilize HIF-1 have shown more mixed results, suggesting that mutations in egl-9 and rhy-1 frequently fail to extend lifespan. Here, we show that egl-9 and rhy-1 mutants suppress the long-lived phenotype of vhl-1 mutants. We also show that RNAi of rhy-1 extends lifespan of wild-type worms while decreasing lifespan of vhl-1 mutant worms. We further identify VHL-1-independent gene expression changes mediated by EGL-9 and RHY-1 and find that a subset of these genes contributes to longevity regulation. The resulting data suggest that changes in HIF-1 activity derived by interactions with EGL-9 likely contribute greatly to its role in regulation of longevity.
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Affiliation(s)
- Joseph C P Kruempel
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Hillary A Miller
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Megan L Schaller
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Abrielle Fretz
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Marshall Howington
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Marjana Sarker
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Shijiao Huang
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Scott F Leiser
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, 48109, USA. .,Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA.
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32
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Friend or foe? Exploring the fine line between Pseudomonas brassicacearum and phytopathogens. J Med Microbiol 2020; 69:347-360. [DOI: 10.1099/jmm.0.001145] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Pseudomonas brassicacearum
is one of over fifty species of bacteria classified into the
P. fluorescens
group. Generally considered a harmless commensal, these bacteria are studied for their plant-growth promotion (PGP) and biocontrol characteristics. Intriguingly,
P. brassicacearum
is closely related to
P. corrugata
, which is classified as an opportunistic phytopathogen. Twenty-one
P. brassicacearum
genomes have been sequenced to date. In the current review, genomes of
P. brassicacearum
and strains from the
P. corrugata
clade were mined for regions associated with PGP, biocontrol and pathogenicity. We discovered that ‘beneficial’ bacteria and those classified as plant pathogens have many genes in common; thus, only a fine line separates beneficial/harmless commensals from those capable of causing disease in plants. The genotype and physiological state of the plant, the presence of biotic/abiotic stressors, and the ability of bacteria to manipulate the plant immune system collectively contribute to how the bacterial-plant interaction plays out. Because production of extracellular metabolites is energetically costly, these compounds are expected to impart a fitness advantage to the producer.
P. brassicacearum
is able to reduce the threat of nematode predation through release of metabolites involved in biocontrol. Moreover this bacterium has the unique ability to form biofilms on the head of Caenorhabditis elegans, as a second mechanism of predator avoidance. Rhizobacteria, plants, fungi, and microfaunal predators have occupied a shared niche for millions of years and, in many ways, they function as a single organism. Accordingly, it is essential that we appreciate the dynamic interplay among these members of the community.
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33
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Velagapudi P, Ghoubrial R, Shah R, Ghali H, Haas M, Patel KS, Riddell A, Blanar CA, Smith RP. A potential tradeoff between feeding rate and aversive learning determines intoxication in a Caenorhabditis elegans host-pathogen system. Microbes Infect 2020; 22:340-348. [PMID: 32014589 DOI: 10.1016/j.micinf.2020.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 01/15/2020] [Accepted: 01/16/2020] [Indexed: 11/29/2022]
Abstract
Despite being the first line of defense against infection, little is known about how host-pathogen interactions determine avoidance. Caenorhabditis elegans can become infected by chemoattractant-producing bacteria through ingestion. The worms can learn to associate these chemoattractants with harm through aversive learning. As a result, the worms will avoid the pathogen. Evolutionary constraints have likely shaped the attraction, intoxication and learning dynamics between bacteria and C. elegans, but these have not been explored. Using bacteria engineered to express an acylhomoserine lactone chemoattractant and a nematicidal protein, we explored how manipulating the amount of attractant produced by the bacteria affects learning and intoxication in mixed stage populations of C. elegans. We found that increasing the production rate of the chemoattractant increased the feeding rate in C. elegans, but decreased the time required for C. elegans to learn to avoid the chemoattractant. Learning generally coincided with a decreased feeding rate. We also observed that the percentage of intoxicated worms was maximized at intermediate production rates of the attractant. We propose that interactions between attractant driven feeding rate and aversive learning are likely responsible for this trend. Our results increase our understanding of behavioral avoidance in C. elegans and have implications in understanding host-pathogen dynamics that shape avoidance.
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Affiliation(s)
- Pallavi Velagapudi
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Rachel Ghoubrial
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Ratnavi Shah
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Helana Ghali
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Meghan Haas
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Krunal S Patel
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Ashleigh Riddell
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Christopher A Blanar
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA
| | - Robert P Smith
- Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA.
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34
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Scott E, Holden-Dye L, O'Connor V, Wand ME. Intra Strain Variation of the Effects of Gram-Negative ESKAPE Pathogens on Intestinal Colonization, Host Viability, and Host Response in the Model Organism Caenorhabditis elegans. Front Microbiol 2020; 10:3113. [PMID: 32038555 PMCID: PMC6985274 DOI: 10.3389/fmicb.2019.03113] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/24/2019] [Indexed: 01/21/2023] Open
Abstract
In its native environment of rotting vegetation, the soil nematode Caenorhabditis elegans encounters a range of bacteria. This includes species from the ESKAPE group of pathogens that pose a clinical problem in acquired hospital infections. Here, we investigated three Gram-negative members of the ESKAPE group, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. Pathogenicity profiles as measured by time to kill adult C. elegans showed that P. aeruginosa was the most pathogenic, followed by K. pneumoniae, while C. elegans cultured on A. baumannii exhibited the same survival as those on the standard laboratory food source for C. elegans, Escherichia coli OP50. The pathogenicity was paralleled by a reduction in time that C. elegans resided on the bacterial lawn with the most pathogenic strains triggering an increase in the frequency of food-leaving. Previous reports indicate that gut colonization is a feature of pathogenicity, but we found that the most pathogenic strains were not associated with the highest level of colonization. Indeed, clearance of P. aeruginosa strains from the C. elegans gut was independent of bacterial pathogenicity. We show that this clearance is regulated by neuromodulation as C. elegans mutants in unc-31 and egl-3 have enhanced clearance of P. aeruginosa. Intriguingly this is also not linked to their pathogenicity. It is likely that there is a dynamic balance occurring in the C. elegans intestinal environment between maintaining a healthy, beneficial microbiota and removal of pathogenic bacteria.
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Affiliation(s)
- Euan Scott
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Lindy Holden-Dye
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Vincent O'Connor
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Matthew E Wand
- National Infection Service, Public Health England, Salisbury, United Kingdom
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Horsman JW, Heinis FI, Miller DL. A Novel Mechanism To Prevent H 2S Toxicity in Caenorhabditis elegans. Genetics 2019; 213:481-490. [PMID: 31371406 PMCID: PMC6781907 DOI: 10.1534/genetics.119.302326] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/24/2019] [Indexed: 11/18/2022] Open
Abstract
Hydrogen sulfide (H2S) is an endogenously produced signaling molecule that can be cytoprotective, especially in conditions of ischemia/reperfusion injury. However, H2S is also toxic, and unregulated accumulation or exposure to environmental H2S can be lethal. In Caenorhabditis elegans, the hypoxia inducible factor (hif-1) coordinates the initial transcriptional response to H2S, and is essential to survive exposure to low concentrations of H2S. We performed a forward genetic screen to identify mutations that suppress the lethality of hif-1 mutant animals in H2S. The mutations we recovered are specific for H2S, as they do not suppress embryonic lethality or reproductive arrest of hif-1 mutant animals in hypoxia, nor can they prevent the death of hif-1 mutant animals exposed to hydrogen cyanide. The majority of hif-1 suppressor mutations we recovered activate the skn-1/Nrf2 transcription factor. Activation of SKN-1 by hif-1 suppressor mutations increased the expression of a subset of H2S-responsive genes, consistent with previous findings that skn-1 plays a role in the transcriptional response to H2S. Using transgenic rescue, we show that overexpression of a single gene, rhy-1, is sufficient to protect hif-1 mutant animals in H2S. The rhy-1 gene encodes a predicated O-acyltransferase enzyme that has previously been shown to negatively regulate HIF-1 activity. Our data indicate that RHY-1 has novel, hif-1 independent, function that promotes survival in H2S.
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Affiliation(s)
- Joseph W Horsman
- Department of Biochemistry, University of Washington School of Medicine, Seattle, Washington 98195
| | - Frazer I Heinis
- Department of Biochemistry, University of Washington School of Medicine, Seattle, Washington 98195
| | - Dana L Miller
- Department of Biochemistry, University of Washington School of Medicine, Seattle, Washington 98195
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The longevity-promoting factor, TCER-1, widely represses stress resistance and innate immunity. Nat Commun 2019; 10:3042. [PMID: 31316054 PMCID: PMC6637209 DOI: 10.1038/s41467-019-10759-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 05/29/2019] [Indexed: 01/01/2023] Open
Abstract
Stress resistance and longevity are positively correlated but emerging evidence indicates that they are physiologically distinct. Identifying factors with distinctive roles in these processes is challenging because pro-longevity genes often enhance stress resistance. We demonstrate that TCER-1, the Caenorhabditis elegans homolog of human transcription elongation and splicing factor, TCERG1, has opposite effects on lifespan and stress resistance. We previously showed that tcer-1 promotes longevity in germline-less C. elegans and reproductive fitness in wild-type animals. Surprisingly, tcer-1 mutants exhibit exceptional resistance against multiple stressors, including infection by human opportunistic pathogens, whereas, TCER-1 overexpression confers immuno-susceptibility. TCER-1 inhibits immunity only during fertile stages of life. Elevating its levels ameliorates the fertility loss caused by infection, suggesting that TCER-1 represses immunity to augment fecundity. TCER-1 acts through repression of PMK-1 as well as PMK-1-independent factors critical for innate immunity. Our data establish key roles for TCER-1 in coordinating immunity, longevity and fertility, and reveal mechanisms that distinguish length of life from functional aspects of aging. Resistance to stress is often associated with increased longevity. Using the model organism C. elegans the authors here show that TCER-1 enhances lifespan while at the same time increasing sensitivity to a number of biotic and abiotic stressors.
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Maxeiner S, Grolleman J, Schmid T, Kammenga J, Hajnal A. The hypoxia-response pathway modulates RAS/MAPK-mediated cell fate decisions in Caenorhabditis elegans. Life Sci Alliance 2019; 2:e201800255. [PMID: 31126994 PMCID: PMC6536719 DOI: 10.26508/lsa.201800255] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 05/16/2019] [Accepted: 05/17/2019] [Indexed: 01/01/2023] Open
Abstract
Animals need to adjust many cellular functions to oxygen availability to adapt to changing environmental conditions. We have used the nematode Caenorhabditis elegans as a model to investigate how variations in oxygen concentrations affect cell fate specification during development. Here, we show that several processes controlled by the conserved RTK/RAS/MAPK pathway are sensitive to changes in the atmospheric oxygen concentration. In the vulval precursor cells (VPCs), the hypoxia-inducible factor HIF-1 activates the expression of the nuclear hormone receptor NHR-57 to counteract RAS/MAPK-induced differentiation. Furthermore, cross-talk between the NOTCH and hypoxia-response pathways modulates the capability of the VPCs to respond to RAS/MAPK signaling. Lateral NOTCH signaling positively regulates the prolyl hydroxylase EGL-9, which promotes HIF-1 degradation in uncommitted VPCs and permits RAS/MAPK-induced differentiation. By inducing DELTA family NOTCH ligands, RAS/MAPK signaling creates a positive feedback loop that represses HIF-1 and NHR-57 expression in the proximal VPCs and keeps them capable of differentiating. This regulatory network formed by the NOTCH, hypoxia, and RAS/MAPK pathways may allow the animals to adapt developmental processes to variations in oxygen concentration.
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Affiliation(s)
- Sabrina Maxeiner
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- PhD Program in Molecular Life Sciences, University and ETH Zurich, Zurich, Switzerland
| | - Judith Grolleman
- Laboratory of Nematology, Wageningen University, Wageningen, The Netherlands
| | - Tobias Schmid
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Jan Kammenga
- Laboratory of Nematology, Wageningen University, Wageningen, The Netherlands
| | - Alex Hajnal
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
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Lloyd MG, Vossler JL, Nomura CT, Moffat JF. Blocking RpoN reduces virulence of Pseudomonas aeruginosa isolated from cystic fibrosis patients and increases antibiotic sensitivity in a laboratory strain. Sci Rep 2019; 9:6677. [PMID: 31040330 PMCID: PMC6491466 DOI: 10.1038/s41598-019-43060-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 04/03/2019] [Indexed: 12/13/2022] Open
Abstract
Multidrug-resistant organisms are increasing in healthcare settings, and there are few antimicrobials available to treat infections from these bacteria. Pseudomonas aeruginosa is an opportunistic pathogen in burn patients and individuals with cystic fibrosis (CF), and a leading cause of nosocomial infections. P. aeruginosa is inherently resistant to many antibiotics and can develop resistance to others, limiting treatment options. P. aeruginosa has multiple sigma factors to regulate transcription. The alternative sigma factor, RpoN (σ54), regulates many virulence genes and is linked to antibiotic resistance. Recently, we described a cis-acting peptide, RpoN*, which is a "molecular roadblock", binding consensus promoters at the -24 site, blocking transcription. RpoN* reduces virulence of P. aeruginosa laboratory strains, but its effects in clinical isolates was unknown. We investigated the effects of RpoN* on phenotypically varied P. aeruginosa strains isolated from CF patients. RpoN* expression reduced motility, biofilm formation, and pathogenesis in a P. aeruginosa-C. elegans infection model. Furthermore, we investigated RpoN* effects on antibiotic susceptibility in a laboratory strain. RpoN* expression increased susceptibility to several beta-lactam-based antibiotics in strain P. aeruginosa PA19660 Xen5. We show that using a cis-acting peptide to block RpoN consensus promoters has potential clinical implications in reducing virulence and improving antibiotic susceptibility.
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Affiliation(s)
- M G Lloyd
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - J L Vossler
- Department of Clinical Laboratory Science, SUNY Upstate Medical University, Syracuse, NY, USA
| | - C T Nomura
- Department of Chemistry, SUNY College of Environmental Science and Forestry, Syracuse, NY, USA
- Center for Applied Microbiology, SUNY College of Environmental Science and Forestry, Syracuse, NY, USA
| | - J F Moffat
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY, USA.
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Khan F, Jain S, Oloketuyi SF. Bacteria and bacterial products: Foe and friends to Caenorhabditis elegans. Microbiol Res 2018; 215:102-113. [DOI: 10.1016/j.micres.2018.06.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/11/2018] [Accepted: 06/24/2018] [Indexed: 02/07/2023]
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Pender CL, Horvitz HR. Hypoxia-inducible factor cell non-autonomously regulates C. elegans stress responses and behavior via a nuclear receptor. eLife 2018; 7:e36828. [PMID: 30010540 PMCID: PMC6078495 DOI: 10.7554/elife.36828] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/15/2018] [Indexed: 12/16/2022] Open
Abstract
The HIF (hypoxia-inducible factor) transcription factor is the master regulator of the metazoan response to chronic hypoxia. In addition to promoting adaptations to low oxygen, HIF drives cytoprotective mechanisms in response to stresses and modulates neural circuit function. How most HIF targets act in the control of the diverse aspects of HIF-regulated biology remains unknown. We discovered that a HIF target, the C. elegans gene cyp-36A1, is required for numerous HIF-dependent processes, including modulation of gene expression, stress resistance, and behavior. cyp-36A1 encodes a cytochrome P450 enzyme that we show controls expression of more than a third of HIF-induced genes. CYP-36A1 acts cell non-autonomously by regulating the activity of the nuclear hormone receptor NHR-46, suggesting that CYP-36A1 functions as a biosynthetic enzyme for a hormone ligand of this receptor. We propose that regulation of HIF effectors through activation of cytochrome P450 enzyme/nuclear receptor signaling pathways could similarly occur in humans.
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Affiliation(s)
- Corinne L Pender
- Department of Biology, Howard Hughes Medical InstituteMassachusetts Institute of TechnologyCambridgeUnited States
- McGovern Institute for Brain ResearchMassachusetts Institute of TechnologyCambridgeUnited States
- Koch Institute for Integrative Cancer ResearchMassachusetts Institute of TechnologyCambridgeUnited States
| | - H Robert Horvitz
- Department of Biology, Howard Hughes Medical InstituteMassachusetts Institute of TechnologyCambridgeUnited States
- McGovern Institute for Brain ResearchMassachusetts Institute of TechnologyCambridgeUnited States
- Koch Institute for Integrative Cancer ResearchMassachusetts Institute of TechnologyCambridgeUnited States
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King CD, Singh D, Holden K, Govan AB, Keith SA, Ghazi A, Robinson RA. Proteomic identification of virulence-related factors in young and aging C. elegans infected with Pseudomonas aeruginosa. J Proteomics 2018; 181:92-103. [DOI: 10.1016/j.jprot.2018.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 03/26/2018] [Accepted: 04/09/2018] [Indexed: 12/16/2022]
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Mion S, Rémy B, Plener L, Chabrière E, Daudé D. [Prevent bacteria from communicating: Divide to cure]. ANNALES PHARMACEUTIQUES FRANÇAISES 2018; 76:249-264. [PMID: 29598881 DOI: 10.1016/j.pharma.2018.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/14/2018] [Accepted: 02/16/2018] [Indexed: 02/07/2023]
Abstract
Quorum Sensing (QS) is a communication system used by numerous bacteria to synchronize their behavior according to the cell density. In this way, bacteria secrete and sense small mediating molecules, called autoinducers (AI), which concentration increases in the environment proportionally to bacterial cell number. QS induces major physiological and phenotypic changes such as virulence induction and biofilm formation. Biofilm represents a physical barrier which shelters bacteria poorly sensitive to antimicrobial treatments and favors the apparition of resistance mechanisms. Disturbing QS is referred to as quorum quenching (QQ). This strategy is used by microorganisms themselves to prevent the development of specific group behaviors. Two strategies are mainly employed: the use of quorum sensing inhibitors (QSI) and of quorum quenching enzymes (QQE) that degrades AI. Many studies have been dedicated to identifying QSI (natural or synthetic) as well as QQE and demonstrating their anti-virulence and anti-biofilm effects on numerous bacterial species. Synergistic effects between QQ and traditional treatments such as antibiotherapy or with reemerging phage therapy have been put forward. The efficiency of numerous QSI and QQE was thereby demonstrated either with in vitro or in vivo animal models leading to the development of medical devices containing QSI and QQE to improve already existing treatments.
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Affiliation(s)
- S Mion
- Aix-Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, 19-21, boulevard Jean-Moulin, 13005 Marseille, France
| | - B Rémy
- Aix-Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, 19-21, boulevard Jean-Moulin, 13005 Marseille, France; Gene&GreenTK, 19-21, boulevard Jean-Moulin, 13005 Marseille, France
| | - L Plener
- Gene&GreenTK, 19-21, boulevard Jean-Moulin, 13005 Marseille, France
| | - E Chabrière
- Aix-Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, 19-21, boulevard Jean-Moulin, 13005 Marseille, France
| | - D Daudé
- Gene&GreenTK, 19-21, boulevard Jean-Moulin, 13005 Marseille, France.
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Rémy B, Mion S, Plener L, Elias M, Chabrière E, Daudé D. Interference in Bacterial Quorum Sensing: A Biopharmaceutical Perspective. Front Pharmacol 2018; 9:203. [PMID: 29563876 PMCID: PMC5845960 DOI: 10.3389/fphar.2018.00203] [Citation(s) in RCA: 171] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 02/22/2018] [Indexed: 12/12/2022] Open
Abstract
Numerous bacteria utilize molecular communication systems referred to as quorum sensing (QS) to synchronize the expression of certain genes regulating, among other aspects, the expression of virulence factors and the synthesis of biofilm. To achieve this process, bacteria use signaling molecules, known as autoinducers (AIs), as chemical messengers to share information. Naturally occurring strategies that interfere with bacterial signaling have been extensively studied in recent years, examining their potential to control bacteria. To interfere with QS, bacteria use quorum sensing inhibitors (QSIs) to block the action of AIs and quorum quenching (QQ) enzymes to degrade signaling molecules. Recent studies have shown that these strategies are promising routes to decrease bacterial pathogenicity and decrease biofilms, potentially enhancing bacterial susceptibility to antimicrobial agents including antibiotics and bacteriophages. The efficacy of QSIs and QQ enzymes has been demonstrated in various animal models and are now considered in the development of new medical devices against bacterial infections, including dressings, and catheters for enlarging the therapeutic arsenal against bacteria.
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Affiliation(s)
- Benjamin Rémy
- IRD, APHM, MEPHI, IHU-Méditerranée Infection, Aix Marseille Université, Marseille, France
- Gene&GreenTK, Marseille, France
| | - Sonia Mion
- IRD, APHM, MEPHI, IHU-Méditerranée Infection, Aix Marseille Université, Marseille, France
| | | | - Mikael Elias
- Department of Biochemistry, Molecular Biology and Biophysics, Biotechnology Institute, University of Minnesota, St. Paul, MN, United States
| | - Eric Chabrière
- IRD, APHM, MEPHI, IHU-Méditerranée Infection, Aix Marseille Université, Marseille, France
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Palominos MF, Verdugo L, Gabaldon C, Pollak B, Ortíz-Severín J, Varas MA, Chávez FP, Calixto A. Transgenerational Diapause as an Avoidance Strategy against Bacterial Pathogens in Caenorhabditis elegans. mBio 2017; 8:e01234-17. [PMID: 29018118 PMCID: PMC5635688 DOI: 10.1128/mbio.01234-17] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 08/30/2017] [Indexed: 12/22/2022] Open
Abstract
The dynamic response of organisms exposed to environmental pathogens determines their survival or demise, and the outcome of this interaction depends on the host's susceptibility and pathogen-dependent virulence factors. The transmission of acquired information about the nature of a pathogen to progeny may ensure effective defensive strategies for the progeny's survival in adverse environments. Environmental RNA interference (RNAi) is a systemic and heritable mechanism and has recently been linked to antibacterial and antifungal defenses in both plants and animals. Here, we report that the second generation of Caenorhabditis elegans living on pathogenic bacteria can avoid bacterial infection by entering diapause in an RNAi pathway-dependent mechanism. Furthermore, we demonstrate that the information encoding this survival strategy is transgenerationally transmitted to the progeny via the maternal germ line.IMPORTANCE Bacteria vastly influence physiology and behavior, and yet, the specific mechanisms by which they cause behavioral changes in hosts are not known. We use C. elegans as a host and the bacteria they eat to understand how microbes trigger a behavioral change that helps animals to survive. We found that animals faced with an infection for two generations could enter a hibernationlike state, arresting development by forming dauer larvae. Dauers have closed mouths and effectively avoid infection. Animals accumulate information that is transgenerationally transmitted to the next generations to form dauers. This work gives insight on how bacteria communicate in noncanonical ways with their hosts, resulting in long-lasting effects providing survival strategies to the community.
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Affiliation(s)
- M Fernanda Palominos
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Lidia Verdugo
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Carolaing Gabaldon
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Bernardo Pollak
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Javiera Ortíz-Severín
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Macarena A Varas
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Francisco P Chávez
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Andrea Calixto
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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Targeting the alternative sigma factor RpoN to combat virulence in Pseudomonas aeruginosa. Sci Rep 2017; 7:12615. [PMID: 28974743 PMCID: PMC5626770 DOI: 10.1038/s41598-017-12667-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 09/18/2017] [Indexed: 12/22/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative, opportunistic pathogen that infects immunocompromised and cystic fibrosis patients. Treatment is difficult due to antibiotic resistance, and new antimicrobials are needed to treat infections. The alternative sigma factor 54 (σ54, RpoN), regulates many virulence-associated genes. Thus, we evaluated inhibition of virulence in P. aeruginosa by a designed peptide (RpoN molecular roadblock, RpoN*) which binds specifically to RpoN consensus promoters. We expected that RpoN* binding to its consensus promoter sites would repress gene expression and thus virulence by blocking RpoN and/or other transcription factors. RpoN* reduced transcription of approximately 700 genes as determined by microarray analysis, including genes related to virulence. RpoN* expression significantly reduced motility, protease secretion, pyocyanin and pyoverdine production, rhamnolipid production, and biofilm formation. Given the effectiveness of RpoN* in vitro, we explored its effects in a Caenorhabditis elegans–P. aeruginosa infection model. Expression of RpoN* protected C. elegans in a paralytic killing assay, whereas worms succumbed to paralysis and death in its absence. In a slow killing assay, which mimics establishment and proliferation of an infection, C. elegans survival was prolonged when RpoN* was expressed. Thus, blocking RpoN consensus promoter sites is an effective strategy for abrogation of P. aeruginosa virulence.
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Sharma N, Khurana N, Muthuraman A. Lower vertebrate and invertebrate models of Alzheimer's disease - A review. Eur J Pharmacol 2017; 815:312-323. [PMID: 28943103 DOI: 10.1016/j.ejphar.2017.09.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 08/20/2017] [Accepted: 09/13/2017] [Indexed: 02/07/2023]
Abstract
Alzheimer's disease is a common neurodegenerative disorder which is characterized by the presence of beta- amyloid protein and neurofibrillary tangles (NFTs) in the brain. Till now, various higher vertebrate models have been in use to study the pathophysiology of this disease. But, these models possess some limitations like ethical restrictions, high cost, difficult maintenance of large quantity and lesser reproducibility. Besides, various lower chordate animals like Danio rerio, Drosophila melanogaster, Caenorhabditis elegans and Ciona intestinalis have been proved to be an important model for the in vivo determination of targets of drugs with least limitations. In this article, we reviewed different studies conducted on theses models for the better understanding of the pathophysiology of AD and their subsequent application as a potential tool in the preclinical evaluation of new drugs.
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Affiliation(s)
- Neha Sharma
- Department of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Punjab, India
| | - Navneet Khurana
- Department of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Punjab, India
| | - Arunachalam Muthuraman
- Department of Pharmacology, Akal College of Pharmacy and Technical Education, Mastuana Sahib, Sangrur, Punjab, India; Department of Pharmacology, JSS College of Pharmacy, Jagadguru Sri Shivarathreeshwara University, Mysuru 570015, Karnataka, India.
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Richter K, Facal P, Thomas N, Vandecandelaere I, Ramezanpour M, Cooksley C, Prestidge CA, Coenye T, Wormald PJ, Vreugde S. Taking the Silver Bullet Colloidal Silver Particles for the Topical Treatment of Biofilm-Related Infections. ACS APPLIED MATERIALS & INTERFACES 2017; 9:21631-21638. [PMID: 28598149 DOI: 10.1021/acsami.7b03672] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Biofilms are aggregates of bacteria residing in a self-assembled matrix, which protects these sessile cells against external stress, including antibiotic therapies. In light of emerging multidrug-resistant bacteria, alternative strategies to antibiotics are emerging. The present study evaluated the activity of colloidal silver nanoparticles (AgNPs) of different shapes against biofilms formed by Staphylococcus aureus (SA), methicillin-resistant SA (MRSA), and Pseudomonas aeruginosa (PA). Colloidal quasi-spherical, cubic, and star-shaped AgNPs were synthesized, and their cytotoxicity on macrophages (THP-1) and bronchial epithelial cells (Nuli-1) was analyzed by the lactate dehydrogenase assay. The antibiofilm activity was assessed in vitro by the resazurin assay and in an in vivo infection model in Caenorhabditis elegans. Cubic and star-shaped AgNPs induced cytotoxicity, while quasi-spherical AgNPs were not toxic. Quasi-spherical AgNPs showed substantial antibiofilm activity in vitro with 96% (±2%), 97% (±1%), and 98% (±1%) biofilm killing of SA, MRSA, and PA, respectively, while significantly reducing mortality of infected nematodes. The in vivo antibiofilm activity was linked to the accumulation of AgNPs in the intestinal tract of C. elegans as observed by 3D X-ray tomography. Quasi-spherical AgNPs were physically stable in suspension for over 6 months with no observed loss in antibiofilm activity. While toxicity and stability limited the utilization of cubic and star-shaped AgNPs, quasi-spherical AgNPs could be rapidly synthesized, were stable and nontoxic, and showed substantial in vitro and in vivo activity against clinically relevant biofilms. Quasi-spherical AgNPs hold potential as pharmacotherapy, for example, as topical treatment for biofilm-related infections.
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Affiliation(s)
- Katharina Richter
- Department of Surgery, Otolaryngology Head and Neck Surgery, Basil Hetzel Institute for Translational Health Research, The University of Adelaide , Adelaide, South Australia Australia
| | - Paula Facal
- Future Industries Institute, University of South Australia , Mawson Lakes, South Australia Australia
| | - Nicky Thomas
- School of Pharmacy and Medical Sciences, University of South Australia , Adelaide, South Australia Australia
- Adelaide Biofilm Test Facility, Sansom Institute for Health Research, University of South Australia , Adelaide, South Australia Australia
| | | | - Mahnaz Ramezanpour
- Department of Surgery, Otolaryngology Head and Neck Surgery, Basil Hetzel Institute for Translational Health Research, The University of Adelaide , Adelaide, South Australia Australia
| | - Clare Cooksley
- Department of Surgery, Otolaryngology Head and Neck Surgery, Basil Hetzel Institute for Translational Health Research, The University of Adelaide , Adelaide, South Australia Australia
| | - Clive A Prestidge
- School of Pharmacy and Medical Sciences, University of South Australia , Adelaide, South Australia Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Adelaide, South Australia Australia
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University , Gent, Belgium
| | - Peter-John Wormald
- Department of Surgery, Otolaryngology Head and Neck Surgery, Basil Hetzel Institute for Translational Health Research, The University of Adelaide , Adelaide, South Australia Australia
| | - Sarah Vreugde
- Department of Surgery, Otolaryngology Head and Neck Surgery, Basil Hetzel Institute for Translational Health Research, The University of Adelaide , Adelaide, South Australia Australia
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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: 249] [Impact Index Per Article: 35.6] [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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Ganesh PS, Rai RV. Inhibition of quorum-sensing-controlled virulence factors of Pseudomonas aeruginosa by Murraya koenigii essential oil: a study in a Caenorhabditis elegans infectious model. J Med Microbiol 2016; 65:1528-1535. [DOI: 10.1099/jmm.0.000385] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- P. Sankar Ganesh
- Department of Studies in Microbiology, University of Mysore, Manasagangotri, Mysore 570006, Karnataka, India
| | - Ravishankar Vittal Rai
- Department of Studies in Microbiology, University of Mysore, Manasagangotri, Mysore 570006, Karnataka, India
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Pseudomonas brassicacearum strain DF41 kills Caenorhabditis elegans through biofilm-dependent and biofilm-independent mechanisms. Appl Environ Microbiol 2016; 82:6889-6898. [PMID: 27637885 DOI: 10.1128/aem.02199-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas brassicacearum DF41 is a biocontrol agent that suppresses disease caused by the fungal pathogen Sclerotinia sclerotiorum A number of exometabolites are produced by DF41 including the lipopeptide sclerosin, hydrogen cyanide (HCN) and degradative enzymes. Production of these compounds is controlled at both the transcriptional and posttranscriptional level by quorum sensing (QS) and the Gac-two component regulatory system. In order to be successful, a biocontrol agent must persist in the environment at levels sufficient for pathogen control. Bacterivorous predators, including nematodes, represent a challenge to the establishment of introduced microorganisms. In the current study, DF41 was investigated for its ability to resist predation by Caenorhabditis elegans. We discovered that this bacterium is capable of killing C. elegans through two different mechanisms: the first involves exposure to toxic metabolites; and the second entails biofilm formation on the nematode head blocking the buccal cavity. Biofilm formation on nematodes, which has only been reported for Yersinia spp. and Xenorhabdus nematophila, is dependent upon the Gac system. Biofilms were not observed when bacteria were grown on NaCl-containing media, and on C. elegans biofilm-resistant mutants. Co-culturing with nematodes lead to increased expression of the pdfRI-rfiA QS genes and hcnA which is under QS control. HCN was the most nematicidal of the exometabolites, suggesting that this bacterium can respond to predator cues and upregulate expression of toxins accordingly. In summary, DF41 is able to respond to the presence of C. elegans and through two distinct mechanisms it can escape predation. IMPORTANCE Pseudomonas brassicacearum DF41 can suppress fungal pathogens through a process known as biocontrol. To be successful, a biocontrol agent must be able to persist in the environment at levels sufficient for pathogen control. Predators including the nematode Caenorhabditis elegans represent a threat to persistence. The aim of the current study was to investigate the DF41-C. elegans interaction. We discovered that DF41 is able to escape predation through two distinct mechanisms. The first involves exposure to toxic bacterial metabolites and the second entails formation of a sticky coating on the nematode head, called a biofilm, which blocks feeding and causes starvation. This is the first report of a pseudomonad forming biofilms on the C. elegans surface. When grown with C. elegans, DF41 exhibits altered gene expression and metabolite production indicating that this bacterium can sense the presence of these predators and adjust its physiology accordingly.
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