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Momeni SS, Cao X, Xie B, Rainey K, Childers NK, Wu H. Intraspecies interactions of Streptococcus mutans impact biofilm architecture and virulence determinants in childhood dental caries. mSphere 2024; 9:e0077823. [PMID: 38990043 PMCID: PMC11288028 DOI: 10.1128/msphere.00778-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 04/11/2024] [Indexed: 07/12/2024] Open
Abstract
Early childhood dental caries (ECC) is the most common chronic disease among children, especially among low socioeconomic populations. Streptococcus mutans is most frequently associated with initiation of ECC. Although many studies report children with multiple S. mutans strains (i.e., genotypes) have greater odds of developing ECC, studies investigating intraspecies interactions in dental caries are lacking. This study investigates the impact of intraspecies interactions on cariogenic and fitness traits of clinical S. mutans isolates using in vitro and in vivo approaches. Association analysis evaluated if presence of multiple S. mutans genotypes within the first year of colonization was associated with caries. Initially, clinical S. mutans isolates from 10 children were evaluated. S. mutans strains (G09 and G18, most prevalent) isolated from one child were used for subsequent analysis. Biofilm analysis was performed for single and mixed cultures to assess cariogenic traits, including biofilm biomass, intra-polysaccharide, pH, and glucan. Confocal laser scanning microscopy (CLSM) and time-lapse imaging were used to evaluate spatial and temporal biofilm dynamics, respectively. A Drosophila model was used to assess colonization in vivo. Results showed the mean biofilm pH was significantly lower in co-cultured biofilms versus monoculture. Doubling of S. mutans biofilms was observed by CLSM and in vivo colonization in Drosophila for co-cultured S. mutans. Individual strains occupied specific domains in co-culture and G09 contributed most to increased co-culture biofilm thickness and colonization in Drosophila. Biofilm formation and acid production displayed distinct signatures in time-lapsed experiments. This study illuminates that intraspecies interactions of S. mutans significantly impacts biofilm acidity, architecture, and colonization.IMPORTANCEThis study sheds light on the complex dynamics of a key contributor to early childhood dental caries (ECC) by exploring intraspecies interactions of different S. mutans strains and their impact on cariogenic traits. Utilizing clinical isolates from children with ECC, the research highlights significant differences in biofilm architecture and acid production in mixed versus single genotype cultures. The findings reveal that co-cultured S. mutans strains exhibit increased cell density and acidity, with individual strains occupying distinct domains. These insights, enhanced by use of time-lapsed confocal laser scanning microscopy and a Drosophila model, offer a deeper understanding of ECC pathogenesis and potential avenues for targeted interventions.
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Affiliation(s)
- Stephanie S. Momeni
- Department of Oral Rehabilitation and Biosciences, School of Dentistry, Oregon Health & Science University, Portland, Oregon, USA
| | - Xixi Cao
- Department of Oral Rehabilitation and Biosciences, School of Dentistry, Oregon Health & Science University, Portland, Oregon, USA
| | - Baotong Xie
- Department of Oral Rehabilitation and Biosciences, School of Dentistry, Oregon Health & Science University, Portland, Oregon, USA
| | - Katherine Rainey
- Department of Pediatric Dentistry, School of Dentistry, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Noel K. Childers
- Department of Pediatric Dentistry, School of Dentistry, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Hui Wu
- Department of Oral Rehabilitation and Biosciences, School of Dentistry, Oregon Health & Science University, Portland, Oregon, USA
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2
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Pradeu T, Thomma BPHJ, Girardin SE, Lemaitre B. The conceptual foundations of innate immunity: Taking stock 30 years later. Immunity 2024; 57:613-631. [PMID: 38599162 DOI: 10.1016/j.immuni.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 02/23/2024] [Accepted: 03/06/2024] [Indexed: 04/12/2024]
Abstract
While largely neglected over decades during which adaptive immunity captured most of the attention, innate immune mechanisms have now become central to our understanding of immunology. Innate immunity provides the first barrier to infection in vertebrates, and it is the sole mechanism of host defense in invertebrates and plants. Innate immunity also plays a critical role in maintaining homeostasis, shaping the microbiota, and in disease contexts such as cancer, neurodegeneration, metabolic syndromes, and aging. The emergence of the field of innate immunity has led to an expanded view of the immune system, which is no longer restricted to vertebrates and instead concerns all metazoans, plants, and even prokaryotes. The study of innate immunity has given rise to new concepts and language. Here, we review the history and definition of the core concepts of innate immunity, discussing their value and fruitfulness in the long run.
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Affiliation(s)
- Thomas Pradeu
- CNRS UMR 5164 ImmunoConcept, University of Bordeaux, Bordeaux, France; Department of Biological and Medical Sciences, University of Bordeaux, Bordeaux, France; Presidential Fellow, Chapman University, Orange, CA, USA.
| | - Bart P H J Thomma
- Institute for Plant Sciences, University of Cologne, Cologne, Germany
| | - Stephen E Girardin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Bruno Lemaitre
- Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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3
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Cao X, Scoffield J, Xie B, Morton DB, Wu H. Drosophila melanogaster as a model to study polymicrobial synergy and dysbiosis. Front Cell Infect Microbiol 2023; 13:1279380. [PMID: 38192401 PMCID: PMC10773677 DOI: 10.3389/fcimb.2023.1279380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 11/01/2023] [Indexed: 01/10/2024] Open
Abstract
The fruit fly Drosophila melanogaster has emerged as a valuable model for investigating human biology, including the role of the microbiome in health and disease. Historically, studies involving the infection of D. melanogaster with single microbial species have yielded critical insights into bacterial colonization and host innate immunity. However, recent evidence has underscored that multiple microbial species can interact in complex ways through physical connections, metabolic cross-feeding, or signaling exchanges, with significant implications for healthy homeostasis and the initiation, progression, and outcomes of disease. As a result, researchers have shifted their focus toward developing more robust and representative in vivo models of co-infection to probe the intricacies of polymicrobial synergy and dysbiosis. This review provides a comprehensive overview of the pioneering work and recent advances in the field, highlighting the utility of Drosophila as an alternative model for studying the multifaceted microbial interactions that occur within the oral cavity and other body sites. We will discuss the factors and mechanisms that drive microbial community dynamics, as well as their impacts on host physiology and immune responses. Furthermore, this review will delve into the emerging evidence that connects oral microbes to systemic conditions in both health and disease. As our understanding of the microbiome continues to evolve, Drosophila offers a powerful and tractable model for unraveling the complex interplay between host and microbes including oral microbes, which has far-reaching implications for human health and the development of targeted therapeutic interventions.
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Affiliation(s)
- Xixi Cao
- Department of Integrative Biomedical & Diagnostic Sciences, Oregon Health and Science University School of Dentistry, Portland, OR, United States
| | - Jessica Scoffield
- Department of Microbiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Baotong Xie
- Department of Integrative Biomedical & Diagnostic Sciences, Oregon Health and Science University School of Dentistry, Portland, OR, United States
| | - David B. Morton
- Department of Integrative Biomedical & Diagnostic Sciences, Oregon Health and Science University School of Dentistry, Portland, OR, United States
| | - Hui Wu
- Department of Integrative Biomedical & Diagnostic Sciences, Oregon Health and Science University School of Dentistry, Portland, OR, United States
- Department of Microbiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
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4
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Momeni SS, Cao X, Xie B, Rainey K, Childers NK, Wu H. Intraspecies interactions of Streptococcus mutans impact biofilm architecture and virulence determinants in childhood dental caries. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.13.571561. [PMID: 38168339 PMCID: PMC10760078 DOI: 10.1101/2023.12.13.571561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Early childhood dental caries (ECC) is the most common chronic disease among children with a heavy disease burden among low socioeconomic populations. Streptococcus mutans is most frequently associated with initiation of ECC. Many studies report children with multiple S. mutans strains (i.e., genotypes) having greater odds of developing ECC, studies investigating intraspecies interactions in dental caries are lacking. In this study, the impact of intraspecies interactions on cariogenic and fitness traits of clinical S. mutans isolates are investigated using in-vitro and in-vivo approaches. Initially clinical S. mutans isolates of 10 children from a longitudinal epidemiological study were evaluated. S. mutans strains (G09 and G18, most prevalent) isolated from one child were used for subsequent analysis. Association analysis was used to determine if presence of multiple S. mutans genotypes within the first-year of colonization was associated with caries. Biofilm analysis was performed for single and mixed cultures to assess cariogenic traits, including biofilm biomass, intra-polysaccharide, pH, and glucan. Confocal Laser Scanning Microscopy (CLSM) and time-lapse imaging were used to evaluate spatial and temporal biofilm dynamics, respectively. A Drosophila model was used to assess colonization in-vivo. Mean biofilm pH was significantly lower in co-cultured biofilms as compared with monoculture biofilms. Doubling of S. mutans in-vitro biofilms was observed by CLSM and in-vivo colonization in Drosophila for co-cultured S. mutans. Individual strains occupied specific domains in co-culture and G09 contributed most to increased co-culture biofilm thickness and colonization in Drosophila. Biofilm formation and acid production displayed distinct signatures in time-lapsed experiments.
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Affiliation(s)
- Stephanie S. Momeni
- Department of Oral Rehabilitation and Biosciences, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - Xixi Cao
- Department of Oral Rehabilitation and Biosciences, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - Baotong Xie
- Department of Oral Rehabilitation and Biosciences, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - Katherine Rainey
- Department of Pediatric Dentistry, School of Dentistry, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Noel K. Childers
- Department of Pediatric Dentistry, School of Dentistry, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hui Wu
- Department of Oral Rehabilitation and Biosciences, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
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Porzio E, Andrenacci D, Manco G. Thermostable Lactonases Inhibit Pseudomonas aeruginosa Biofilm: Effect In Vitro and in Drosophila melanogaster Model of Chronic Infection. Int J Mol Sci 2023; 24:17028. [PMID: 38069351 PMCID: PMC10707464 DOI: 10.3390/ijms242317028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/23/2023] [Accepted: 11/28/2023] [Indexed: 12/18/2023] Open
Abstract
Pseudomonas aeruginosa is one of the six antimicrobial-resistant pathogens known as "ESKAPE" that represent a global threat to human health and are considered priority targets for the development of novel antimicrobials and alternative therapeutics. The virulence of P. aeruginosa is regulated by a four-chemicals communication system termed quorum sensing (QS), and one main class of QS signals is termed acylhomoserine lactones (acyl-HSLs), which includes 3-Oxo-dodecanoil homoserine lactone (3-Oxo-C12-HSL), which regulates the expression of genes implicated in virulence and biofilm formation. Lactonases, like Paraoxonase 2 (PON2) from humans and the phosphotriesterase-like lactonases (PLLs) from thermostable microorganisms, are able to hydrolyze acyl-HSLs. In this work, we explored in vitro and in an animal model the effect of some lactonases on the production of Pseudomonas virulence factors. This study presents a model of chronic infection in which bacteria were administered by feeding, and Drosophila adults were treated with enzymes and the antibiotic tobramycin, alone or in combination. In vitro, we observed significant effects of lactonases on biofilm formation as well as effects on bacterial motility and the expression of virulence factors. The treatment in vivo by feeding with the lactonase SacPox allowed us to significantly increase the biocidal effect of tobramycin in chronic infection.
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Affiliation(s)
- Elena Porzio
- Institute of Biochemistry and Cell Biology, National Research Council of Italy, Via P. Castellino 111, 80131 Naples, Italy
| | - Davide Andrenacci
- CNR Institute of Molecular Genetics “Luigi-Luca Cavalli-Sforza” Unit of Bologna, 40136 Bologna, Italy
| | - Giuseppe Manco
- Institute of Biochemistry and Cell Biology, National Research Council of Italy, Via P. Castellino 111, 80131 Naples, Italy
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6
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Touré H, Herrmann JL, Szuplewski S, Girard-Misguich F. Drosophila melanogaster as an organism model for studying cystic fibrosis and its major associated microbial infections. Infect Immun 2023; 91:e0024023. [PMID: 37847031 PMCID: PMC10652941 DOI: 10.1128/iai.00240-23] [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: 10/18/2023] Open
Abstract
Cystic fibrosis (CF) is a human genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator gene that encodes a chloride channel. The most severe clinical manifestation is associated with chronic pulmonary infections by pathogenic and opportunistic microbes. Drosophila melanogaster has become the invertebrate model of choice for modeling microbial infections and studying the induced innate immune response. Here, we review its contribution to the understanding of infections with six major pathogens associated with CF (Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia cepacia, Mycobacterium abscessus, Streptococcus pneumoniae, and Aspergillus fumigatus) together with the perspectives opened by the recent availability of two CF models in this model organism.
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Affiliation(s)
- Hamadoun Touré
- Université Paris-Saclay, UVSQ, INSERM, Infection et Inflammation, Montigny-le-Bretonneux, France
| | - Jean-Louis Herrmann
- Université Paris-Saclay, UVSQ, INSERM, Infection et Inflammation, Montigny-le-Bretonneux, France
- Assistance Publique-Hôpitaux de Paris, Hôpitaux Universitaires Ile-de-France Ouest, GHU Paris-Saclay, Hôpital Raymond Poincaré, Garches, France
| | - Sébastien Szuplewski
- Université Paris-Saclay, UVSQ, Laboratoire de Génétique et Biologie Cellulaire, Montigny-le-Bretonneux, France
| | - Fabienne Girard-Misguich
- Université Paris-Saclay, UVSQ, INSERM, Infection et Inflammation, Montigny-le-Bretonneux, France
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7
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Wang Z, Yong H, Zhang S, Liu Z, Zhao Y. Colonization Resistance of Symbionts in Their Insect Hosts. INSECTS 2023; 14:594. [PMID: 37504600 PMCID: PMC10380809 DOI: 10.3390/insects14070594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 06/25/2023] [Accepted: 06/29/2023] [Indexed: 07/29/2023]
Abstract
The symbiotic microbiome is critical in promoting insect resistance against colonization by exogenous microorganisms. The mechanisms by which symbionts contribute to the host's immune capacity is referred to as colonization resistance. Symbionts can protect insects from exogenous pathogens through a variety of mechanisms, including upregulating the expression of host immune-related genes, producing antimicrobial substances, and competitively excluding pathogens. Concordantly, insects have evolved fine-tuned regulatory mechanisms to avoid overactive immune responses against symbionts or specialized cells to harbor symbionts. Alternatively, some symbionts have evolved special adaptations, such as the formation of biofilms to increase their tolerance to host immune responses. Here, we provide a review of the mechanisms about colonization resistance of symbionts in their insect hosts. Adaptations of symbionts and their insect hosts that may maintain such symbiotic relationships, and the significance of such relationships in the coevolution of symbiotic systems are also discussed to provide insights into the in-depth study of the contribution of symbionts to host physiology and behavior.
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Affiliation(s)
- Zhengyan Wang
- School of Food and Strategic Reserves, Henan University of Technology, Zhengzhou 450001, China
| | - Hanzi Yong
- School of Food and Strategic Reserves, Henan University of Technology, Zhengzhou 450001, China
| | - Shan Zhang
- School of Food and Strategic Reserves, Henan University of Technology, Zhengzhou 450001, China
| | - Zhiyuan Liu
- School of Food and Strategic Reserves, Henan University of Technology, Zhengzhou 450001, China
| | - Yaru Zhao
- School of Grain Science and Technology, Jiangsu University of Science and Technology, Zhenjiang 212100, China
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8
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Michaelis C, Grohmann E. Horizontal Gene Transfer of Antibiotic Resistance Genes in Biofilms. Antibiotics (Basel) 2023; 12:antibiotics12020328. [PMID: 36830238 PMCID: PMC9952180 DOI: 10.3390/antibiotics12020328] [Citation(s) in RCA: 68] [Impact Index Per Article: 68.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/08/2023] Open
Abstract
Most bacteria attach to biotic or abiotic surfaces and are embedded in a complex matrix which is known as biofilm. Biofilm formation is especially worrisome in clinical settings as it hinders the treatment of infections with antibiotics due to the facilitated acquisition of antibiotic resistance genes (ARGs). Environmental settings are now considered as pivotal for driving biofilm formation, biofilm-mediated antibiotic resistance development and dissemination. Several studies have demonstrated that environmental biofilms can be hotspots for the dissemination of ARGs. These genes can be encoded on mobile genetic elements (MGEs) such as conjugative and mobilizable plasmids or integrative and conjugative elements (ICEs). ARGs can be rapidly transferred through horizontal gene transfer (HGT) which has been shown to occur more frequently in biofilms than in planktonic cultures. Biofilm models are promising tools to mimic natural biofilms to study the dissemination of ARGs via HGT. This review summarizes the state-of-the-art of biofilm studies and the techniques that visualize the three main HGT mechanisms in biofilms: transformation, transduction, and conjugation.
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9
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Razvi E, Whitfield GB, Reichhardt C, Dreifus JE, Willis AR, Gluscencova OB, Gloag ES, Awad TS, Rich JD, da Silva DP, Bond W, Le Mauff F, Sheppard DC, Hatton BD, Stoodley P, Reinke AW, Boulianne GL, Wozniak DJ, Harrison JJ, Parsek MR, Howell PL. Glycoside hydrolase processing of the Pel polysaccharide alters biofilm biomechanics and Pseudomonas aeruginosa virulence. NPJ Biofilms Microbiomes 2023; 9:7. [PMID: 36732330 PMCID: PMC9894940 DOI: 10.1038/s41522-023-00375-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 01/16/2023] [Indexed: 02/04/2023] Open
Abstract
Pel exopolysaccharide biosynthetic loci are phylogenetically widespread biofilm matrix determinants in bacteria. In Pseudomonas aeruginosa, Pel is crucial for cell-to-cell interactions and reducing susceptibility to antibiotic and mucolytic treatments. While genes encoding glycoside hydrolases have long been linked to biofilm exopolysaccharide biosynthesis, their physiological role in biofilm development is unclear. Here we demonstrate that the glycoside hydrolase activity of P. aeruginosa PelA decreases adherent biofilm biomass and is responsible for generating the low molecular weight secreted form of the Pel exopolysaccharide. We show that the generation of secreted Pel contributes to the biomechanical properties of the biofilm and decreases the virulence of P. aeruginosa in Caenorhabditis elegans and Drosophila melanogaster. Our results reveal that glycoside hydrolases found in exopolysaccharide biosynthetic systems can help shape the soft matter attributes of a biofilm and propose that secreted matrix components be referred to as matrix associated to better reflect their influence.
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Affiliation(s)
- Erum Razvi
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Gregory B Whitfield
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
- Département de Microbiologie, Infectiologie, et Immunologie, Faculté de Médecine Université de Montréal, Montréal, QC, Canada
| | - Courtney Reichhardt
- Department of Microbiology, University of Washington, Seattle, WA, USA
- Department of Chemistry, Washington University, St. Louis, MO, USA
| | - Julia E Dreifus
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Alexandra R Willis
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Oxana B Gluscencova
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Erin S Gloag
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, 43210, USA
- Department of Biomedical Sciences and Pathobiology, VA-MD College of Veterinary Medicine, Virginia Tech, VA, 24061, USA
| | - Tarek S Awad
- Department of Materials Science and Engineering, University of Toronto, Toronto, ON, Canada
| | - Jacquelyn D Rich
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Daniel Passos da Silva
- Department of Microbiology, University of Washington, Seattle, WA, USA
- BioVectra Inc. 11 Aviation, Charlottetown, PE, Canada
| | - Whitney Bond
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - François Le Mauff
- Department of Microbiology and Immunology, Faculty of Medicine, McGill University, Montreal, QC, Canada
- Infectious Disease and Immunity in Global Health, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- McGill Interdisciplinary Initiative in Infection and Immunity, Montreal, QC, Canada
| | - Donald C Sheppard
- Department of Microbiology and Immunology, Faculty of Medicine, McGill University, Montreal, QC, Canada
- Infectious Disease and Immunity in Global Health, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- McGill Interdisciplinary Initiative in Infection and Immunity, Montreal, QC, Canada
| | - Benjamin D Hatton
- Department of Materials Science and Engineering, University of Toronto, Toronto, ON, Canada
| | - Paul Stoodley
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, 43210, USA
- Department of Orthopedics, The Ohio State University, Columbus, OH, 43210, USA
- National Biofilm Innovation Centre (NBIC) and National Centre for Advanced Tribology at Southampton (nCATS), University of Southampton, Southampton, SO17 1BJ, UK
- Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA
| | - Aaron W Reinke
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Gabrielle L Boulianne
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Daniel J Wozniak
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, 43210, USA
- Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA
| | - Joe J Harrison
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Matthew R Parsek
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - P Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada.
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
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Wiesmann CL, Zhang Y, Alford M, Hamilton CD, Dosanjh M, Thoms D, Dostert M, Wilson A, Pletzer D, Hancock REW, Haney CH. The ColR/S two-component system is a conserved determinant of host association across Pseudomonas species. THE ISME JOURNAL 2023; 17:286-296. [PMID: 36424517 PMCID: PMC9859794 DOI: 10.1038/s41396-022-01343-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 11/27/2022]
Abstract
Members of the bacterial genus Pseudomonas form mutualistic, commensal, and pathogenic associations with diverse hosts. The prevalence of host association across the genus suggests that symbiosis may be a conserved ancestral trait and that distinct symbiotic lifestyles may be more recently evolved. Here we show that the ColR/S two-component system, part of the Pseudomonas core genome, is functionally conserved between Pseudomonas aeruginosa and Pseudomonas fluorescens. Using plant rhizosphere colonization and virulence in a murine abscess model, we show that colR is required for commensalism with plants and virulence in animals. Comparative transcriptomics revealed that the ColR regulon has diverged between P. aeruginosa and P. fluorescens and deleting components of the ColR regulon revealed strain-specific, but not host-specific, requirements for ColR-dependent genes. Collectively, our results suggest that ColR/S allows Pseudomonas to sense and respond to a host, but that the ColR-regulon has diverged between Pseudomonas strains with distinct lifestyles. This suggests that conservation of two-component systems, coupled with life-style dependent diversification of the regulon, may play a role in host association and lifestyle transitions.
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Affiliation(s)
- Christina L Wiesmann
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Yue Zhang
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Morgan Alford
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
- 2259 Lower Mall Research Station, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Corri D Hamilton
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Manisha Dosanjh
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - David Thoms
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Melanie Dostert
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
- 2259 Lower Mall Research Station, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Andrew Wilson
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Daniel Pletzer
- 2259 Lower Mall Research Station, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Microbiology and Immunology, University of Otago, 720 Cumberland St., 9054, Dunedin, New Zealand
| | - Robert E W Hancock
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
- 2259 Lower Mall Research Station, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Cara H Haney
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
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11
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Zhou D, Huang G, Xu G, Xiang L, Huang S, Chen X, Zhang Y, Wang D. CRISPRi-Mediated Gene Suppression Reveals Putative Reverse Transcriptase Gene PA0715 to Be a Global Regulator of Pseudomonas aeruginosa. Infect Drug Resist 2022; 15:7577-7599. [PMID: 36579125 PMCID: PMC9792118 DOI: 10.2147/idr.s384980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 11/09/2022] [Indexed: 12/24/2022] Open
Abstract
Purpose Pseudomonas aeruginosa is a common pathogen of infection in burn and trauma patients, and multi-drug resistant P. aeruginosa has become an increasingly important pathogen. Essential genes are key to the development of novel antibiotics. The PA0715 gene is a novel unidentified essential gene that has attracted our interest as a potential antibiotic target. Our study aims to determine the exact role of PA0715 in cell physiology and bacterial pathogenicity, providing important clues for antibiotic development. Patients and Methods The shuttle vector pHERD20T containing an arabinose inducible promoter was used to construct the CRISPRi system. Alterations in cellular physiology and bacterial pathogenicity of P. aeruginosa PAO1 after PA0715 inhibition were characterized. High-throughput RNA-seq was performed to gain more insight into the mechanisms by which PA0715 regulates the vital activity of P. aeruginosa. Results We found that down-regulation of PA0715 significantly reduced PAO1 growth rate, motility and chemotaxis, antibiotic resistance, pyocyanin and biofilm production. In addition, PA0715 inhibition reduced the pathogenicity of PAO1 to the greater galleria mellonella larvae. Transcriptional profiling identified 1757 genes including those related to amino acid, carbohydrate, ketone body and organic salt metabolism, whose expression was directly or indirectly controlled by PA0715. Unexpectedly, genes involved in oxidative phosphorylation also varied with PA0715 levels, and these findings support a hitherto unrecognized critical role for PA0715 in oxidative respiration in P. aeruginosa. Conclusion We identified PA0715 as a global regulator of the metabolic network that is indispensable for the survival and reproduction of P. aeruginosa. Our results provide a basis for future studies of potential antibiotic targets for P. aeruginosa and offer new ideas for P. aeruginosa infection control.
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Affiliation(s)
- Dapeng Zhou
- Department of Burns and Plastic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People’s Republic of China
- The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, People’s Republic of China
| | - Guangtao Huang
- Department of Burns and Plastic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People’s Republic of China
- The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, People’s Republic of China
- Department of Burn and Plastic Surgery, Department of Wound Repair, Shenzhen Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People’s Hospital, Shenzhen, People’s Republic of China
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China
| | - Guangchao Xu
- Department of Burns and Plastic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People’s Republic of China
- The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, People’s Republic of China
| | - Lijuan Xiang
- Department of Clinical Laboratory, Shenzhen Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People’s Hospital, Shenzhen, People’s Republic of China
| | - Siyi Huang
- Department of Burns and Plastic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People’s Republic of China
- The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, People’s Republic of China
| | - Xinchong Chen
- Department of Burns and Plastic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People’s Republic of China
- The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, People’s Republic of China
| | - Yixin Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China
| | - Dali Wang
- Department of Burns and Plastic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, People’s Republic of China
- The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, People’s Republic of China
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12
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Dilemma and a way out for bacterial biofilm research. J Med Microbiol 2022; 71. [DOI: 10.1099/jmm.0.001586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Biofilm-associated infections (BAIs) are more common in clinical practice and have become a public health problem of global concern. We present our views on current research (detection methods, mechanism research, animal model construction, treatment strategies, etc.) on biofilms and BAIs, and discuss future developments concerning this important issue.
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13
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Pseudomonas aeruginosa Secretes the Oxylipin Autoinducer Synthases OdsA and OdsB via the Xcp Type 2 Secretion System. J Bacteriol 2022; 204:e0011422. [PMID: 35658521 DOI: 10.1128/jb.00114-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The oxylipin-dependent quorum-sensing system (ODS) of Pseudomonas aeruginosa relies on the production and sensing of two extracellular oxylipins, 10S-hydroxy-(8E)-octadecenoic acid (10-HOME) and 7S,10S-dihydroxy-(8E)-octadecenoic acid (7,10-DiHOME). Here, we implemented a genetic screen of P. aeruginosa strain PAO1 aimed to identify genes required for 10-HOME and 7,10-DiHOME production. Among the 14 genes identified, four encoded previously known components of the ODS and 10 encoded parts of the Xcp type II secretion system (T2SS). We subsequently created a clean xcpQ deletion mutant, which encodes the necessary outer membrane component of Xcp, and found it recapitulated the impaired functionality of the T2SS transposon mutants. Further studies showed that the ΔxcpQ mutant was unable to secrete the oxylipin synthase enzymes across the outer membrane. Specifically, immunoblotting for OdsA, which is responsible for the generation of 10-HOME from oleic acid, detected the enzyme in supernatants from wild-type PAO1 but not ΔxcpQ cultures. Likewise, chromatography of supernatants found that 10-HOME was not in supernatants collected from the ΔxcpQ mutant. Accordingly, diol synthase activity was increased in the periplasm of ΔxcpQ mutant consistent with a stoppage in its transport. Importantly, after exposure of the ΔxcpQ mutant to exogenous 10-HOME and 7,10-DiHOME, the ODS effector genes become active; thus, the sensing component of the ODS does not involve the T2SS. Finally, we observed that Xcp contributed to robust in vitro and in vivo biofilm formation in oleic acid availability- and ODS-dependent manner. Thus, T2SS-mediated transport of the oxylipin synthase enzymes to outside the bacterial cell is required for ODS functionality. IMPORTANCE We previously showed that the ODS of P. aeruginosa produces and responds to oxylipins derived from host oleic acid by enhancing biofilm formation and virulence. Here, we developed a genetic screen strategy to explore the molecular basis for oxylipins synthesis and detection. Unexpectedly, we found that the ODS autoinducer synthases cross the outer membrane using the Xcp type 2 secretion system (T2SS) of P. aeruginosa, and so the biosynthesis of oxylipins occurs extracellularly. T2SS promoted biofilm formation in the presence of oleic acid as a result of ODS activation. Our results identify two new T2SS secreted proteins in P. aeruginosa and reveal a new way by which this important opportunistic pathogen interacts with the host environment.
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14
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Azimi S, Lewin GR, Whiteley M. The biogeography of infection revisited. Nat Rev Microbiol 2022; 20:579-592. [PMID: 35136217 PMCID: PMC9357866 DOI: 10.1038/s41579-022-00683-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2022] [Indexed: 01/01/2023]
Abstract
Many microbial communities, including those involved in chronic human infections, are patterned at the micron scale. In this Review, we summarize recent work that has defined the spatial arrangement of microorganisms in infection and begun to demonstrate how changes in spatial patterning correlate with disease. Advances in microscopy have refined our understanding of microbial micron-scale biogeography in samples from humans. These findings then serve as a benchmark for studying the role of spatial patterning in preclinical models, which provide experimental versatility to investigate the interplay between biogeography and pathogenesis. Experimentation using preclinical models has begun to show how spatial patterning influences the interactions between cells, their ability to coexist, their virulence and their recalcitrance to treatment. Future work to study the role of biogeography in infection and the functional biogeography of microorganisms will further refine our understanding of the interplay of spatial patterning, pathogen virulence and disease outcomes.
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Affiliation(s)
- Sheyda Azimi
- School of Biological Sciences and Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
| | - Gina R Lewin
- Emory-Children's Cystic Fibrosis Center, Atlanta, GA, USA
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15
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Bugs on Drugs: A Drosophila melanogaster Gut Model to Study In Vivo Antibiotic Tolerance of E. coli. Microorganisms 2022; 10:microorganisms10010119. [PMID: 35056568 PMCID: PMC8780219 DOI: 10.3390/microorganisms10010119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/23/2021] [Accepted: 01/05/2022] [Indexed: 02/04/2023] Open
Abstract
With an antibiotic crisis upon us, we need to boost antibiotic development and improve antibiotics’ efficacy. Crucial is knowing how to efficiently kill bacteria, especially in more complex in vivo conditions. Indeed, many bacteria harbor antibiotic-tolerant persisters, variants that survive exposure to our most potent antibiotics and catalyze resistance development. However, persistence is often only studied in vitro as we lack flexible in vivo models. Here, I explored the potential of using Drosophila melanogaster as a model for antimicrobial research, combining methods in Drosophila with microbiology techniques: assessing fly development and feeding, generating germ-free or bacteria-associated Drosophila and in situ microscopy. Adult flies tolerate antibiotics at high doses, although germ-free larvae show impaired development. Orally presented E. coli associates with Drosophila and mostly resides in the crop. E. coli shows an overall high antibiotic tolerance in vivo potentially resulting from heterogeneity in growth rates. The hipA7 high-persistence mutant displays an increased antibiotic survival while the expected low persistence of ΔrelAΔspoT and ΔrpoS mutants cannot be confirmed in vivo. In conclusion, a Drosophila model for in vivo antibiotic tolerance research shows high potential and offers a flexible system to test findings from in vitro assays in a broader, more complex condition.
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16
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Thees AV, Pietrosimone KM, Melchiorre CK, Marden JN, Graf J, Lynes MA, Maltz-Matyschsyk M. PmtA Regulates Pyocyanin Expression and Biofilm Formation in Pseudomonas aeruginosa. Front Microbiol 2021; 12:789765. [PMID: 34867928 PMCID: PMC8636135 DOI: 10.3389/fmicb.2021.789765] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 10/18/2021] [Indexed: 01/30/2023] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa expresses a small molecular weight, cysteine-rich protein (PmtA), identified as a metallothionein (MT) protein family member. The MT family proteins have been well-characterized in eukaryotes as essential for zinc and copper homeostasis, protection against oxidative stress, and the ability to modify a variety of immune activities. Bacterial MTs share sequence homology, antioxidant chemistry, and heavy metal-binding capacity with eukaryotic MTs, however, the impact of bacterial MTs on virulence and infection have not been well-studied. In the present study, we investigated the role of PmtA in P. aeruginosa PAO1 using a PmtA-deficient strain (ΔpmtA). Here we demonstrated the virulence factor, pyocyanin, relies on the expression of PmtA. We showed that PmtA may be protective against oxidative stress, as an alternative antioxidant, glutathione, can rescue pyocyanin expression. Furthermore, the expression of phzM, which encodes a pyocyanin precursor enzyme, was decreased in the ΔpmtA mutant during early stationary phase. Upregulated pmtA expression was previously detected in confluent biofilms, which are essential for chronic infection, and we observed that the ΔpmtA mutant was disrupted for biofilm formation. As biofilms also modulate antibiotic susceptibility, we examined the ΔpmtA mutant susceptibility to antibiotics and found that the ΔpmtA mutant is more susceptible to cefepime and ciprofloxacin than the wild-type strain. Finally, we observed that the deletion of pmtA results in decreased virulence in a waxworm model. Taken together, our results support the conclusion that PmtA is necessary for the full virulence of P. aeruginosa and may represent a potential target for therapeutic intervention.
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Affiliation(s)
- Amy V Thees
- Department of Molecular and Cell Biology, University of Connecticut, Mansfield, CT, United States
| | - Kathryn M Pietrosimone
- Department of Molecular and Cell Biology, University of Connecticut, Mansfield, CT, United States
| | - Clare K Melchiorre
- Department of Molecular and Cell Biology, University of Connecticut, Mansfield, CT, United States
| | - Jeremiah N Marden
- Department of Molecular and Cell Biology, University of Connecticut, Mansfield, CT, United States
| | - Joerg Graf
- Department of Molecular and Cell Biology, University of Connecticut, Mansfield, CT, United States
| | - Michael A Lynes
- Department of Molecular and Cell Biology, University of Connecticut, Mansfield, CT, United States
| | - Michele Maltz-Matyschsyk
- Department of Molecular and Cell Biology, University of Connecticut, Mansfield, CT, United States
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17
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Bronnec V, Alexeyev OA. In vivo model of Propionibacterium (Cutibacterium) spp. biofilm in Drosophila melanogaster. Anaerobe 2021; 72:102450. [PMID: 34619359 DOI: 10.1016/j.anaerobe.2021.102450] [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: 04/17/2021] [Revised: 08/27/2021] [Accepted: 09/14/2021] [Indexed: 01/12/2023]
Abstract
OBJECTIVES Acne vulgaris is a common inflammatory disorder of the pilosebaceous unit and Propionibacterium acnes biofilm-forming ability is believed to be a contributing factor to the disease development. In vivo models mimicking hair follicle environment are lacking. The aim of this study was to develop an in vivo Propionibacterium spp. biofilm model in Drosophila melanogaster (fruit fly). METHODS We created a sterile line of D. melanogaster able to sustain Propionibacterium spp. biofilms in the gut. In order to mimic the lipid-rich, anaerobic environment of the hair follicle, fruit flies were maintained on lipid-rich diet. Propionibacterium spp. biofilms were visualized by immunofluorescence and scanning electron microscopy. We further tested if the biofilm-dispersal activity of DNase I can be demonstrated in the developed model. RESULTS We have demonstrated the feasibility of our in vivo model for development and study of P. acnes, P. granulosum and P. avidum biofilms. The model is suitable to evaluate dispersal as well as other agents against P. acnes biofilm. CONCLUSIONS We report a novel in vivo model for studying Propionibacterium spp. biofilms. The model can be suitable for both mechanistic as well as interventional studies.
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Affiliation(s)
- Vicky Bronnec
- Department of Pathology, Medical Biosciences, Umeå University, Umeå, Sweden
| | - Oleg A Alexeyev
- Department of Pathology, Medical Biosciences, Umeå University, Umeå, Sweden.
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18
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O-Specific Antigen-Dependent Surface Hydrophobicity Mediates Aggregate Assembly Type in Pseudomonas aeruginosa. mBio 2021; 12:e0086021. [PMID: 34372703 PMCID: PMC8406328 DOI: 10.1128/mbio.00860-21] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Bacteria live in spatially organized aggregates during chronic infections, where they adapt to the host environment, evade immune responses, and resist therapeutic interventions. Although it is known that environmental factors such as polymers influence bacterial aggregation, it is not clear how bacterial adaptation during chronic infection impacts the formation and spatial organization of aggregates in the presence of polymers. Here, we show that in an in vitro model of cystic fibrosis (CF) containing the polymers extracellular DNA (eDNA) and mucin, O-specific antigen is a major factor determining the formation of two distinct aggregate assembly types of Pseudomonas aeruginosa due to alterations in cell surface hydrophobicity. Our findings suggest that during chronic infection, the interplay between cell surface properties and polymers in the environment may influence the formation and structure of bacterial aggregates, which would shed new light on the fitness costs and benefits of O-antigen production in environments such as CF lungs.
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19
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Bier E, Nizet V. Driving to Safety: CRISPR-Based Genetic Approaches to Reducing Antibiotic Resistance. Trends Genet 2021; 37:745-757. [PMID: 33745750 DOI: 10.1016/j.tig.2021.02.007] [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: 12/11/2020] [Revised: 02/23/2021] [Accepted: 02/23/2021] [Indexed: 02/07/2023]
Abstract
Bacterial resistance to antibiotics has reached critical levels, skyrocketing in hospitals and the environment and posing a major threat to global public health. The complex and challenging problem of reducing antibiotic resistance (AR) requires a network of both societal and science-based solutions to preserve the most lifesaving pharmaceutical intervention known to medicine. In addition to developing new classes of antibiotics, it is essential to safeguard the clinical efficacy of existing drugs. In this review, we examine the potential application of novel CRISPR-based genetic approaches to reducing AR in both environmental and clinical settings and prolonging the utility of vital antibiotics.
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Affiliation(s)
- Ethan Bier
- Tata Institute for Genetics and Society, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0349, USA; Section of Cell and Developmental Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0349, USA.
| | - Victor Nizet
- Tata Institute for Genetics and Society, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0349, USA; Collaborative to Halt Antibiotic-Resistant Microbes, Department of Pediatrics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0687, USA; Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0687, USA
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20
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Thomsen K, Kobayashi O, Kishi K, Shirai R, Østrup Jensen P, Heydorn A, Hentzer M, Calum H, Christophersen L, Høiby N, Moser C. Animal models of chronic and recurrent Pseudomonas aeruginosa lung infection: significance of macrolide treatment. APMIS 2021; 130:458-476. [PMID: 34117660 DOI: 10.1111/apm.13161] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/01/2021] [Accepted: 06/07/2021] [Indexed: 11/28/2022]
Abstract
Animal models of human diseases are invaluable and inevitable elements in identifying and testing novel treatments for serious diseases, including severe infections. Planning and conducting investigator-initiated human trials are generally accepted as being enormously challenging. In contrast, it is often underestimated how much planning, including background and modifying experiments, is needed to establish a relevant infectious disease animal model. However, representative animal infectious models, well designed to test generated hypotheses, are useful to improve our understanding of pathogenesis, virulence factors and host response and to identify novel treatment candidates and therapeutic strategies. Such results can subsequently proceed to clinical testing if suitable. The present review aims at presenting all the pulmonary Pseudomonas aeruginosa infectious models we have knowledge of and the detailed descriptions of established animal models in our laboratory focusing on macrolide therapy are presented.
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Affiliation(s)
- Kim Thomsen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Osamu Kobayashi
- Department of Infectious Diseases, National Cancer Center Hospital, Tokyo, Japan
| | - Kenji Kishi
- Oitaken Kouseiren Tsurumi Hospital, Tsurumi, Beppu City, Japan
| | - Ryo Shirai
- Department of Internal Medicine, Kawasaki Medical School, General Medical Center, Okayama, Japan
| | - Peter Østrup Jensen
- Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Arne Heydorn
- Department of Endocrinology and Nephrology, Nordsjaellands Hospital, Hillerød, Denmark
| | - Morten Hentzer
- Department of Molecular Pharmacology, H. Lundbeck A/S, Copenhagen, Denmark
| | - Henrik Calum
- Department of Clinical Microbiology, Hvidovre Hospital, Copenhagen University Hospital, Copenhagen, Denmark
| | - Lars Christophersen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Niels Høiby
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Claus Moser
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
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21
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Teoh MC, Furusawa G, Veera Singham G. Multifaceted interactions between the pseudomonads and insects: mechanisms and prospects. Arch Microbiol 2021; 203:1891-1915. [PMID: 33634321 DOI: 10.1007/s00203-021-02230-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 12/19/2020] [Accepted: 02/11/2021] [Indexed: 02/07/2023]
Abstract
Insects and bacteria are the most widespread groups of organisms found in nearly all habitats on earth, establishing diverse interactions that encompass the entire range of possible symbiotic associations from strict parasitism to obligate mutualism. The complexity of their interactions is instrumental in shaping the roles of insects in the environment, meanwhile ensuring the survival and persistence of the associated bacteria. This review aims to provide detailed insight on the multifaceted symbiosis between one of the most versatile bacterial genera, Pseudomonas (Gammaproteobacteria: Pseudomonadaceae) and a diverse group of insect species. The Pseudomonas engages with varied interactions with insects, being either a pathogen or beneficial endosymbiont, as well as using insects as vectors. In addition, this review also provides updates on existing and potential applications of Pseudomonas and their numerous insecticidal metabolites as biocontrol agents against pest insects for the improvement of integrated pest management strategies. Here, we have summarized several known modes of action and the virulence factors of entomopathogenic Pseudomonas strains essential for their pathogenicity against insects. Meanwhile, the beneficial interactions between pseudomonads and insects are currently limited to a few known insect taxa, despite numerous studies reporting identification of pseudomonads in the guts and haemocoel of various insect species. The vector-symbiont association between pseudomonads and insects can be diverse from strict phoresy to a role switch from commensalism to parasitism following a dose-dependent response. Overall, the pseudomonads appeared to have evolved independently to be either exclusively pathogenic or beneficial towards insects.
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Affiliation(s)
- Miao-Ching Teoh
- Centre for Chemical Biology, Universiti Sains Malaysia, 11900, Bayan Lepas, Penang, Malaysia
| | - Go Furusawa
- Centre for Chemical Biology, Universiti Sains Malaysia, 11900, Bayan Lepas, Penang, Malaysia
| | - G Veera Singham
- Centre for Chemical Biology, Universiti Sains Malaysia, 11900, Bayan Lepas, Penang, Malaysia.
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22
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Drosophila as a model for studying cystic fibrosis pathophysiology of the gastrointestinal system. Proc Natl Acad Sci U S A 2020; 117:10357-10367. [PMID: 32345720 DOI: 10.1073/pnas.1913127117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cystic fibrosis (CF) is a recessive disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. The most common symptoms include progressive lung disease and chronic digestive conditions. CF is the first human genetic disease to benefit from having five different species of animal models. Despite the phenotypic differences among the animal models and human CF, these models have provided invaluable insight into understanding disease mechanisms at the organ-system level. Here, we identify a member of the ABCC4 family, CG5789, that has the structural and functional properties expected for encoding the Drosophila equivalent of human CFTR, and thus refer to it as Drosophila CFTR (Dmel\CFTR). We show that knockdown of Dmel\CFTR in the adult intestine disrupts osmotic homeostasis and displays CF-like phenotypes that lead to intestinal stem cell hyperplasia. We also show that expression of wild-type human CFTR, but not mutant variants of CFTR that prevent plasma membrane expression, rescues the mutant phenotypes of Dmel\CFTR Furthermore, we performed RNA sequencing (RNA-Seq)-based transcriptomic analysis using Dmel\CFTR fly intestine and identified a mucin gene, Muc68D, which is required for proper intestinal barrier protection. Altogether, our findings suggest that Drosophila can be a powerful model organism for studying CF pathophysiology.
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23
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Samadder S. Drosophila melanogaster: A Robust Tool to Study Candidate Drug against Epidemic and Pandemic Diseases. ANIMAL MODELS IN MEDICINE AND BIOLOGY 2020. [DOI: 10.5772/intechopen.90073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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24
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Lewenza S, Johnson L, Charron-Mazenod L, Hong M, Mulcahy-O'Grady H. Extracellular DNA controls expression of Pseudomonas aeruginosa genes involved in nutrient utilization, metal homeostasis, acid pH tolerance and virulence. J Med Microbiol 2020; 69:895-905. [PMID: 32242794 DOI: 10.1099/jmm.0.001184] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Introduction. Pseudomonas aeruginosa grows in extracellular DNA (eDNA)-enriched biofilms and infection sites. eDNA is generally considered to be a structural biofilm polymer required for aggregation and biofilm maturation. In addition, eDNA can sequester divalent metal cations, acidify growth media and serve as a nutrient source.Aim. We wanted to determine the genome-wide influence on the transcriptome of planktonic P. aeruginosa PAO1 grown in the presence of eDNA.Methodology. RNA-seq analysis was performed to determine the genome-wide effects on gene expression of PAO1 grown with eDNA. Transcriptional lux fusions were used to confirm eDNA regulation and to validate phenotypes associated with growth in eDNA.Results. The transcriptome of eDNA-regulated genes included 89 induced and 76 repressed genes (FDR<0.05). A large number of eDNA-induced genes appear to be involved in utilizing DNA as a nutrient. Several eDNA-induced genes are also induced by acidic pH 5.5, and eDNA/acidic pH promoted an acid tolerance response in P. aeruginosa. The cyoABCDE terminal oxidase is induced by both eDNA and pH 5.5, and contributed to the acid tolerance phenotype. Quantitative metal analysis confirmed that DNA binds to diverse metals, which helps explain why many genes involved in a general uptake of metals were controlled by eDNA. Growth in the presence of eDNA also promoted intracellular bacterial survival and influenced virulence in the acute infection model of fruit flies.Conclusion. The diverse functions of the eDNA-regulated genes underscore the important role of this extracellular polymer in promoting antibiotic resistance, virulence, acid tolerance and nutrient utilization; phenotypes that contribute to long-term survival.
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Affiliation(s)
- Shawn Lewenza
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Cummings School of Medicine, Snyder Institute of Chronic Diseases, Calgary, Alberta, Canada.,Athabasca University, Faculty of Science and Technology, Athabasca, Alberta, Canada
| | - Lori Johnson
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Cummings School of Medicine, Snyder Institute of Chronic Diseases, Calgary, Alberta, Canada
| | - Laetitia Charron-Mazenod
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Cummings School of Medicine, Snyder Institute of Chronic Diseases, Calgary, Alberta, Canada
| | - Mia Hong
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Cummings School of Medicine, Snyder Institute of Chronic Diseases, Calgary, Alberta, Canada
| | - Heidi Mulcahy-O'Grady
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Cummings School of Medicine, Snyder Institute of Chronic Diseases, Calgary, Alberta, Canada
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25
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Virulence-Inhibiting Herbal Compound Falcarindiol Significantly Reduced Mortality in Mice Infected with Pseudomonas aeruginosa. Antibiotics (Basel) 2020; 9:antibiotics9030136. [PMID: 32213958 PMCID: PMC7148489 DOI: 10.3390/antibiotics9030136] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/18/2020] [Accepted: 03/21/2020] [Indexed: 12/13/2022] Open
Abstract
Antipathogenic compounds that target the virulence of pathogenic bacteria rather than their viability offer a promising alternative approach to treat infectious diseases. Using extracts from 30 Chinese herbs that are known for treating symptoms resembling infections, we identified an active compound falcarindiol from Notopterygium incisum Ting ex H. T. Chang that showed potent inhibitory activities against Pseudomonas aeruginosa multiple virulence factors. Falcarindiol significantly repressed virulence-related genes, including the type III secretion system (T3SS); quorum sensing synthase genes lasIR and rhlIR; lasB; motility-related genes fliC and fliG; and phenazine synthesis genes phzA1 and phzA2. P. aeruginosa swarming motility and pyocyanin production were reduced significantly. In a burned mouse model, falcarindiol treatment significantly reduced the mortality in mice infected with P. aeruginosa, indicating that falcarindiol is a promising antipathogenic drug candidate for treating P. aeruginosa infections.
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Hegde S, Nilyanimit P, Kozlova E, Anderson ER, Narra HP, Sahni SK, Heinz E, Hughes GL. CRISPR/Cas9-mediated gene deletion of the ompA gene in symbiotic Cedecea neteri impairs biofilm formation and reduces gut colonization of Aedes aegypti mosquitoes. PLoS Negl Trop Dis 2019; 13:e0007883. [PMID: 31790395 PMCID: PMC6907859 DOI: 10.1371/journal.pntd.0007883] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 12/12/2019] [Accepted: 10/26/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Symbiotic bacteria are pervasive in mosquitoes and their presence can influence many host phenotypes that affect vectoral capacity. While it is evident that environmental and host genetic factors contribute in shaping the microbiome of mosquitoes, we have a poor understanding regarding how bacterial genetics affects colonization of the mosquito gut. The CRISPR/Cas9 gene editing system is a powerful tool to alter bacterial genomes facilitating investigations into host-microbe interactions but has yet to be applied to insect symbionts. METHODOLOGY/PRINCIPAL FINDINGS To investigate the role of bacterial genetic factors in mosquito biology and in colonization of mosquitoes we used CRISPR/Cas9 gene editing system to mutate the outer membrane protein A (ompA) gene of a Cedecea neteri symbiont isolated from Aedes mosquitoes. The ompA mutant had an impaired ability to form biofilms and poorly infected Ae. aegypti when reared in a mono-association under gnotobiotic conditions. In adult mosquitoes, the mutant had a significantly reduced infection prevalence compared to the wild type or complement strains, while no differences in prevalence were seen in larvae, suggesting genetic factors are particularly important for adult gut colonization. We also used the CRISPR/Cas9 system to integrate genes (antibiotic resistance and fluorescent markers) into the symbionts genome and demonstrated that these genes were functional in vitro and in vivo. CONCLUSIONS/SIGNIFICANCE Our results shed insights into the role of ompA gene in host-microbe interactions in Ae. aegypti and confirm that CRISPR/Cas9 gene editing can be employed for genetic manipulation of non-model gut microbes. The ability to use this technology for site-specific integration of genes into the symbiont will facilitate the development of paratransgenic control strategies to interfere with arboviral pathogens such Chikungunya, dengue, Zika and Yellow fever viruses transmitted by Aedes mosquitoes.
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Affiliation(s)
- Shivanand Hegde
- Departments of Vector Biology and Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Pornjarim Nilyanimit
- Center of Excellence in Clinical Virology, Chulalongkorn University, Bangkok, Thailand
| | - Elena Kozlova
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Enyia R. Anderson
- Departments of Vector Biology and Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Hema P. Narra
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Sanjeev K. Sahni
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Eva Heinz
- Department of Vector Biology and Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Grant L. Hughes
- Departments of Vector Biology and Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Hotinger JA, May AE. Animal Models of Type III Secretion System-Mediated Pathogenesis. Pathogens 2019; 8:pathogens8040257. [PMID: 31766664 PMCID: PMC6963218 DOI: 10.3390/pathogens8040257] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/18/2019] [Accepted: 11/20/2019] [Indexed: 01/22/2023] Open
Abstract
The type III secretion system (T3SS) is a conserved virulence factor used by many Gram-negative pathogenic bacteria and has become an important target for anti-virulence drugs. Most T3SS inhibitors to date have been discovered using in vitro screening assays. Pharmacokinetics and other important characteristics of pharmaceuticals cannot be determined with in vitro assays alone. In vivo assays are required to study pathogens in their natural environment and are an important step in the development of new drugs and vaccines. Animal models are also required to understand whether T3SS inhibition will enable the host to clear the infection. This review covers selected animal models (mouse, rat, guinea pig, rabbit, cat, dog, pig, cattle, primates, chicken, zebrafish, nematode, wax moth, flea, fly, and amoeba), where T3SS activity and infectivity have been studied in relation to specific pathogens (Escherichia coli, Salmonella spp., Pseudomonas spp., Shigella spp., Bordetella spp., Vibrio spp., Chlamydia spp., and Yersinia spp.). These assays may be appropriate for those researching T3SS inhibition.
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Abstract
Two areas of research that have greatly increased in attention are: dipterans as vectors and the microbes they are capable of vectoring. Because it is the front-end of the fly that first encounters these microbes, this review focuses on the legs, mouthparts, and foregut, which includes the crop as major structures involved in dipteran vectoring ability. The legs and mouthparts are generally involved in mechanical transmission of microbes. However, the crop is involved in more than just mechanical transmission, for it is within the lumen of the crop that microbes are taken up with the meal of the fly, stored, and it is within the lumen that horizontal transmission of bacterial resistance has been demonstrated. In addition to storage of microbes, the crop is also involved in depositing the microbes via a process known as regurgitation. Various aspects of crop regulation are discussed and specific examples of crop involvement with microorganisms are discussed. The importance of biofilm and biofilm formation are presented, as well as, some physical parameters of the crop that might either facilitate or inhibit biofilm formation. Finally, there is a brief discussion of dipteran model systems for studying crop microbe interactions.
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Affiliation(s)
- John G Stoffolano
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, United States
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29
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Capo F, Wilson A, Di Cara F. The Intestine of Drosophila melanogaster: An Emerging Versatile Model System to Study Intestinal Epithelial Homeostasis and Host-Microbial Interactions in Humans. Microorganisms 2019; 7:microorganisms7090336. [PMID: 31505811 PMCID: PMC6780840 DOI: 10.3390/microorganisms7090336] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 08/16/2019] [Accepted: 09/03/2019] [Indexed: 12/31/2022] Open
Abstract
In all metazoans, the intestinal tract is an essential organ to integrate nutritional signaling, hormonal cues and immunometabolic networks. The dysregulation of intestinal epithelium functions can impact organism physiology and, in humans, leads to devastating and complex diseases, such as inflammatory bowel diseases, intestinal cancers, and obesity. Two decades ago, the discovery of an immune response in the intestine of the genetic model system, Drosophila melanogaster, sparked interest in using this model organism to dissect the mechanisms that govern gut (patho) physiology in humans. In 2007, the finding of the intestinal stem cell lineage, followed by the development of tools available for its manipulation in vivo, helped to elucidate the structural organization and functions of the fly intestine and its similarity with mammalian gastrointestinal systems. To date, studies of the Drosophila gut have already helped to shed light on a broad range of biological questions regarding stem cells and their niches, interorgan communication, immunity and immunometabolism, making the Drosophila a promising model organism for human enteric studies. This review summarizes our current knowledge of the structure and functions of the Drosophila melanogaster intestine, asserting its validity as an emerging model system to study gut physiology, regeneration, immune defenses and host-microbiota interactions.
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Affiliation(s)
- Florence Capo
- Department of Microbiology and Immunology, IWK Research Centre, Dalhousie University, 5850/5980 University Avenue, Halifax, NS B3K 6R8, Canada.
| | - Alexa Wilson
- Department of Microbiology and Immunology, IWK Research Centre, Dalhousie University, 5850/5980 University Avenue, Halifax, NS B3K 6R8, Canada.
| | - Francesca Di Cara
- Department of Microbiology and Immunology, IWK Research Centre, Dalhousie University, 5850/5980 University Avenue, Halifax, NS B3K 6R8, Canada.
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30
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Hakimzadeh A, Okshevsky M, Maisuria V, Déziel E, Tufenkji N. Exposure to Freeze-Thaw Conditions Increases Virulence of Pseudomonas aeruginosa to Drosophila melanogaster. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:14180-14186. [PMID: 30444353 DOI: 10.1021/acs.est.8b04900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Groundwater contamination by pathogenic bacteria present in land-applied manure poses a threat to public health. In cold climate regions, surface soil layers experience repeated temperature fluctuations around the freezing point known as freeze-thaw (FT) cycles. With global climate change, annual soil FT cycles have increased, and this trend is expected to continue. It is therefore of interest to understand how FT cycles impact soil microbial communities. This study investigates the influence of FT cycles on the growth, culturability, biofilm formation, and virulence of the bacterial opportunistic pathogen Pseudomonas aeruginosa, a ubiquitous bacterium found in soil and water, responsible for infections in immunocompromised hosts. Our findings demonstrate that exposure to FT had no significant effect on growth or culturability of the bacteria. However, FT treatment significantly increased biofilm formation and delayed the onset of swimming motility, factors that are important for the pathogenicity of P. aeruginosa. An in vivo study using a chronic infection model revealed an increase in the virulence of P. aeruginosa after FT exposure. These results suggest that the impact of climate change on natural FT cycles may be affecting the ecology of soil-borne pathogens and host-pathogen interactions in unexpected ways.
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Affiliation(s)
- Arsham Hakimzadeh
- Department of Chemical Engineering , McGill University , 3610 University Street , Montréal , Québec H3A 0C5 , Canada
- INRS-Institut Armand-Frappier , 531 boulevard des Prairies , Laval , Québec H7V 1B7 , Canada
| | - Mira Okshevsky
- Department of Chemical Engineering , McGill University , 3610 University Street , Montréal , Québec H3A 0C5 , Canada
| | - Vimal Maisuria
- Department of Chemical Engineering , McGill University , 3610 University Street , Montréal , Québec H3A 0C5 , Canada
| | - Eric Déziel
- INRS-Institut Armand-Frappier , 531 boulevard des Prairies , Laval , Québec H7V 1B7 , Canada
| | - Nathalie Tufenkji
- Department of Chemical Engineering , McGill University , 3610 University Street , Montréal , Québec H3A 0C5 , Canada
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Two Regulators, PA3898 and PA2100, Modulate the Pseudomonas aeruginosa Multidrug Resistance MexAB-OprM and EmrAB Efflux Pumps and Biofilm Formation. Antimicrob Agents Chemother 2018; 62:AAC.01459-18. [PMID: 30297364 DOI: 10.1128/aac.01459-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 09/29/2018] [Indexed: 11/20/2022] Open
Abstract
It is generally believed that the Pseudomonas aeruginosa biofilm matrix itself acts as a molecular sieve or sink that contributes to significant levels of drug resistance, but it is becoming more apparent that multidrug efflux pumps induced during biofilm growth significantly enhance resistance levels. We present here a novel transcriptional regulator, PA3898, which controls biofilm formation and multidrug efflux pumps in P. aeruginosa A mutant of this regulator significantly reduced the ability of P. aeruginosa to produce biofilm in vitro and affected its in vivo fitness and pathogenesis in Drosophila melanogaster and BALB/c mouse lung infection models. Transcriptome analysis revealed that PA3898 modulates essential virulence genes/pathways, including multidrug efflux pumps and phenazine biosynthesis. Chromatin immunoprecipitation sequencing (ChIP-seq) identified its DNA binding sequences and confirmed that PA3898 directly interacts with promoter regions of four genes/operons, two of which are mexAB-oprM and phz2 Coimmunoprecipitation revealed a regulatory partner of PA3898 as PA2100, and both are required for binding to DNA in electrophoretic mobility shift assays. PA3898 and PA2100 were given the names MdrR1 and MdrR2, respectively, as novel repressors of the mexAB-oprM multidrug efflux operon and activators for another multidrug efflux pump, EmrAB. The interaction between MdrR1 and MdrR2 at the promoter regions of their regulons was further characterized via localized surface plasmon resonance and DNA footprinting. These regulators directly repress the mexAB-oprM operon, independent of its well-established MexR regulator. Mutants of mdrR1 and mdrR2 caused increased resistance to multiple antibiotics in P. aeruginosa, validating the significance of these newly discovered regulators.
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Secreted Phosphatase and Deoxyribonuclease Are Required by Pseudomonas aeruginosa To Defend against Neutrophil Extracellular Traps. Infect Immun 2018; 86:IAI.00403-18. [PMID: 29967090 DOI: 10.1128/iai.00403-18] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 06/23/2018] [Indexed: 11/20/2022] Open
Abstract
Neutrophil extracellular traps (NETs) are produced by neutrophils as an innate immune defense mechanism to trap and kill microbial pathogens. NETs are comprised of ejected chromatin that forms a lattice structure enmeshed with numerous antimicrobial proteins. In addition to forming the structural backbone of NETs, extracellular DNA (eDNA) has membrane-disrupting antimicrobial activity that contributes to NET killing. Many pathogens produce secreted extracellular DNases to evade the antimicrobial activity of NETs. Pseudomonas aeruginosa encodes an operon of two secreted enzymes, a predicted alkaline phosphatase and a DNase. The DNase (eddB) degrades eDNA to use as a nutrient source. Here we report that both eDNA and NETs are potent inducers of this DNase-phosphatase operon. Furthermore, the secreted DNase contributes to degrading NET DNA and defends P. aeruginosa against NET-mediated killing. We demonstrate that EddA has both alkaline phosphatase and phosphodiesterase (PDase) activities and also protects against the antimicrobial activity of NETs. Although the phosphatase does not cause DNA degradation similar to that of the DNase, its protective function is likely a result of removing the cation-chelating phosphates from the eDNA phosphodiester backbone. Therefore, both the DNase and PDase contribute to defense against NET killing of P. aeruginosa, highlighting the role of DNA-manipulating enzymes in targeting the eDNA in neutrophil extracellular traps.
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33
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Heacock-Kang Y, Zarzycki-Siek J, Sun Z, Poonsuk K, Bluhm AP, Cabanas D, Fogen D, McMillan IA, Chuanchuen R, Hoang TT. Novel dual regulators of Pseudomonas aeruginosa essential for productive biofilms and virulence. Mol Microbiol 2018; 109:401-414. [PMID: 29995308 PMCID: PMC6158065 DOI: 10.1111/mmi.14063] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/25/2018] [Indexed: 01/14/2023]
Abstract
Gene regulation network in Pseudomonas aeruginosa is complex. With a relatively large genome (6.2 Mb), there is a significant portion of genes that are proven or predicted to be transcriptional regulators. Many of these regulators have been shown to play important roles in biofilm formation and maintenance. In this study, we present a novel transcriptional regulator, PA1226, which modulates biofilm formation and virulence in P. aeruginosa. Mutation in the gene encoding this regulator abolished the ability of P. aeruginosa to produce biofilms in vitro, without any effect on the planktonic growth. This regulator is also essential for the in vivo fitness and pathogenesis in both Drosophila melanogaster and BALB/c mouse lung infection models. Transcriptome analysis revealed that PA1226 regulates many essential virulence genes/pathways, including those involved in alginate, pili, and LPS biosynthesis. Genes/operons directly regulated by PA1226 and potential binding sequences were identified via ChIP-seq. Attempts to confirm the binding sequences by electrophoretic mobility shift assay led to the discovery of a co-regulator, PA1413, via co-immunoprecipitation assay. PA1226 and PA1413 were shown to bind collaboratively to the promoter regions of their regulons. A model is proposed, summarizing our finding on this novel dual-regulation system.
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Affiliation(s)
- Yun Heacock-Kang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Jan Zarzycki-Siek
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Zhenxin Sun
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Kanchana Poonsuk
- Department of Veterinary Public Health, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Andrew P Bluhm
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Darlene Cabanas
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Dawson Fogen
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Ian A McMillan
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Rungtip Chuanchuen
- Department of Veterinary Public Health, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Tung T Hoang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
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Nijampatnam B, Zhang H, Cai X, Michalek SM, Wu H, Velu SE. Inhibition of Streptococcus mutans Biofilms by the Natural Stilbene Piceatannol Through the Inhibition of Glucosyltransferases. ACS OMEGA 2018; 3:8378-8385. [PMID: 30087944 PMCID: PMC6072251 DOI: 10.1021/acsomega.8b00367] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 06/12/2018] [Indexed: 06/08/2023]
Abstract
Removal of oral biofilms involves the use of broad-spectrum antimicrobials, which eradicate both pathogenic and protective oral commensal species. Ideal therapeutics for dental caries should be able to selectively inhibit pathogenic biofilms caused by Streptococcus mutans. S. mutans extracellular glucosyltransferases (Gtfs), particularly GtfB and GtfC, synthesize predominantly water-insoluble glucans, which contribute to the structural scaffold of biofilms. The lead stilbene identified through our docking study against the catalytic domain of GtfC is a natural product known as piceatannol, which inhibited S. mutans biofilm formation in a dose-dependent manner, with considerable selectivity over growth inhibition of S. mutans and commensal streptococci. Binding kinetic analysis of piceatannol was performed using Octet RED against both GtfB and GtfC, which produced low micromolar KD values. Piceatannol inhibited S. mutans colonization in an in vivo drosophila model and a rat model of dental caries.
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Affiliation(s)
- Bhavitavya Nijampatnam
- Department
of Chemistry, University of Alabama at Birmingham, 901 14th Street S, Birmingham, Alabama 35294, United States
| | - Hua Zhang
- Department
of Pediatric Dentistry, University of Alabama at Birmingham, 1919 7th Avenue South, Birmingham, Alabama 35294, United States
| | - Xia Cai
- Department
of Microbiology, University of Alabama at
Birmingham, 1720 2nd
Avenue South, Birmingham, Alabama 35294, United
States
| | - Suzanne M. Michalek
- Department
of Microbiology, University of Alabama at
Birmingham, 1720 2nd
Avenue South, Birmingham, Alabama 35294, United
States
| | - Hui Wu
- Department
of Pediatric Dentistry, University of Alabama at Birmingham, 1919 7th Avenue South, Birmingham, Alabama 35294, United States
| | - Sadanandan E. Velu
- Department
of Chemistry, University of Alabama at Birmingham, 901 14th Street S, Birmingham, Alabama 35294, United States
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Magana M, Sereti C, Ioannidis A, Mitchell CA, Ball AR, Magiorkinis E, Chatzipanagiotou S, Hamblin MR, Hadjifrangiskou M, Tegos GP. Options and Limitations in Clinical Investigation of Bacterial Biofilms. Clin Microbiol Rev 2018; 31:e00084-16. [PMID: 29618576 PMCID: PMC6056845 DOI: 10.1128/cmr.00084-16] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria can form single- and multispecies biofilms exhibiting diverse features based upon the microbial composition of their community and microenvironment. The study of bacterial biofilm development has received great interest in the past 20 years and is motivated by the elegant complexity characteristic of these multicellular communities and their role in infectious diseases. Biofilms can thrive on virtually any surface and can be beneficial or detrimental based upon the community's interplay and the surface. Advances in the understanding of structural and functional variations and the roles that biofilms play in disease and host-pathogen interactions have been addressed through comprehensive literature searches. In this review article, a synopsis of the methodological landscape of biofilm analysis is provided, including an evaluation of the current trends in methodological research. We deem this worthwhile because a keyword-oriented bibliographical search reveals that less than 5% of the biofilm literature is devoted to methodology. In this report, we (i) summarize current methodologies for biofilm characterization, monitoring, and quantification; (ii) discuss advances in the discovery of effective imaging and sensing tools and modalities; (iii) provide an overview of tailored animal models that assess features of biofilm infections; and (iv) make recommendations defining the most appropriate methodological tools for clinical settings.
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Affiliation(s)
- Maria Magana
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
| | - Christina Sereti
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Microbiology, Thriassio General Hospital, Attiki, Greece
| | - Anastasios Ioannidis
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Nursing, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Sparta, Greece
| | - Courtney A Mitchell
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Anthony R Ball
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
| | - Emmanouil Magiorkinis
- Department of Hygiene, Epidemiology and Medical Statistics, Medical School, University of Athens, Athens-Goudi, Greece
| | | | - Michael R Hamblin
- Harvard-MIT Division of Health Science and Technology, Cambridge, Massachusetts, USA
- Department of Dermatology, Harvard Medical School, Boston, Massachusetts, USA
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Maria Hadjifrangiskou
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - George P Tegos
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
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Pais IS, Valente RS, Sporniak M, Teixeira L. Drosophila melanogaster establishes a species-specific mutualistic interaction with stable gut-colonizing bacteria. PLoS Biol 2018; 16:e2005710. [PMID: 29975680 PMCID: PMC6049943 DOI: 10.1371/journal.pbio.2005710] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 07/17/2018] [Accepted: 06/12/2018] [Indexed: 02/07/2023] Open
Abstract
Animals live together with diverse bacteria that can impact their biology. In Drosophila melanogaster, gut-associated bacterial communities are relatively simple in composition but also have a strong impact on host development and physiology. It is generally assumed that gut bacteria in D. melanogaster are transient and their constant ingestion with food is required to maintain their presence in the gut. Here, we identify bacterial species from wild-caught D. melanogaster that stably associate with the host independently of continuous inoculation. Moreover, we show that specific Acetobacter wild isolates can proliferate in the gut. We further demonstrate that the interaction between D. melanogaster and the wild isolated Acetobacter thailandicus is mutually beneficial and that the stability of the gut association is key to this mutualism. The stable population in the gut of D. melanogaster allows continuous bacterial spreading into the environment, which is advantageous to the bacterium itself. The bacterial dissemination is in turn advantageous to the host because the next generation of flies develops in the presence of this particularly beneficial bacterium. A. thailandicus leads to a faster host development and higher fertility of emerging adults when compared to other bacteria isolated from wild-caught flies. Furthermore, A. thailandicus is sufficient and advantageous when D. melanogaster develops in axenic or freshly collected figs, respectively. This isolate of A. thailandicus colonizes several genotypes of D. melanogaster but not the closely related D. simulans, indicating that the stable association is host specific. This work establishes a new conceptual model to understand D. melanogaster-gut microbiota interactions in an ecological context; stable interactions can be mutualistic through microbial farming, a common strategy in insects. Moreover, these results develop the use of D. melanogaster as a model to study gut microbiota proliferation and colonization.
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Affiliation(s)
- Inês S. Pais
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | | | | | - Luis Teixeira
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal
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37
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Siva-Jothy JA, Prakash A, Vasanthakrishnan RB, Monteith KM, Vale PF. Oral Bacterial Infection and Shedding in Drosophila melanogaster. J Vis Exp 2018. [PMID: 29912178 PMCID: PMC6101445 DOI: 10.3791/57676] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The fruit fly Drosophila melanogaster is one of the best developed model systems of infection and innate immunity. While most work has focused on systemic infections, there has been a recent increase of interest in the mechanisms of gut immunocompetence to pathogens, which require methods to orally infect flies. Here we present a protocol to orally expose individual flies to an opportunistic bacterial pathogen (Pseudomonas aeruginosa) and a natural bacterial pathogen of D. melanogaster (Pseudomonas entomophila). The goal of this protocol is to provide a robust method to expose male and female flies to these pathogens. We provide representative results showing survival phenotypes, microbe loads, and bacterial shedding, which is relevant for the study of heterogeneity in pathogen transmission. Finally, we confirm that Dcy mutants (lacking the protective peritrophic matrix in the gut epithelium) and Relish mutants (lacking a functional immune deficiency (IMD) pathway), show increased susceptibility to bacterial oral infection. This protocol, therefore, describes a robust method to infect flies using the oral route of infection, which can be extended to the study of a variety genetic and environmental sources of variation in gut infection outcomes and bacterial transmission.
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Affiliation(s)
- Jonathon A Siva-Jothy
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh
| | - Arun Prakash
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh
| | | | - Katy M Monteith
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh
| | - Pedro F Vale
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh; Centre for Immunity, Infection and Evolution, University of Edinburgh;
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38
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Lindberg HM, McKean KA, Caraco T, Wang IN. Within-host dynamics and random duration of pathogen infection: Implications for between-host transmission. J Theor Biol 2018; 446:137-148. [PMID: 29391172 DOI: 10.1016/j.jtbi.2018.01.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 12/27/2017] [Accepted: 01/26/2018] [Indexed: 01/15/2023]
Abstract
Taking an ecological perspective, this paper reports theoretical and empirical results concerning fatal bacterial infections of adult insects. Two models, each combining deterministic and stochastic elements, characterize how the pathogen's dynamics might govern an infected host's mortality rate. We analyze the models in detail for exponential pathogen growth, and apply them to observed insect mortality when the pathogen's growth is unregulated. We then allow bacteriophage to generate fluctuations in the within-host pathogen density; we demonstrate that only one of our models matches host mortality rates when pathogen growth is regulated by phage. We generalize our results on mortality hazard of individual hosts to analyze how random duration of the infectious period can combine with probabilistic transmission events to affect between-host transmission.
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Affiliation(s)
- Heather M Lindberg
- Department of Biological Sciences, University at Albany, Albany, NY 12222, USA; Center for Science and Health Professions, Virginia Western Community College, Roanoke, VA 24015, USA
| | - Kurt A McKean
- School of Biological, Biomedical and Environmental Sciences, University of Hull, Hull HU6 7RX, UK
| | - T Caraco
- Department of Biological Sciences, University at Albany, Albany, NY 12222, USA
| | - Ing-Nang Wang
- Department of Biological Sciences, University at Albany, Albany, NY 12222, USA.
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Little AS, Okkotsu Y, Reinhart AA, Damron FH, Barbier M, Barrett B, Oglesby-Sherrouse AG, Goldberg JB, Cody WL, Schurr MJ, Vasil ML, Schurr MJ. Pseudomonas aeruginosa AlgR Phosphorylation Status Differentially Regulates Pyocyanin and Pyoverdine Production. mBio 2018; 9:e02318-17. [PMID: 29382736 PMCID: PMC5790918 DOI: 10.1128/mbio.02318-17] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 12/18/2017] [Indexed: 12/31/2022] Open
Abstract
Pseudomonas aeruginosa employs numerous, complex regulatory elements to control expression of its many virulence systems. The P. aeruginosa AlgZR two-component regulatory system controls the expression of several crucial virulence phenotypes. We recently determined, through transcriptomic profiling of a PAO1 ΔalgR mutant strain compared to wild-type PAO1, that algZR and hemCD are cotranscribed and show differential iron-dependent gene expression. Previous expression profiling was performed in strains without algR and revealed that AlgR acts as either an activator or repressor, depending on the gene. Thus, examination of P. aeruginosa gene expression from cells locked into different AlgR phosphorylation states reveals greater physiological relevance. Therefore, gene expression from strains carrying algR alleles encoding a phosphomimetic (AlgR D54E) or a phosphoablative (AlgR D54N) form were compared by microarray to PAO1. Transcriptome analyses of these strains revealed 25 differentially expressed genes associated with iron siderophore biosynthesis or heme acquisition or production. The PAO1 algR D54N mutant produced lower levels of pyoverdine but increased expression of the small RNAs prrf1 and prrf2 compared to PAO1. In contrast, the algR D54N mutant produced more pyocyanin than wild-type PAO1. On the other hand, the PAO1 algR D54E mutant produced higher levels of pyoverdine, likely due to increased expression of an iron-regulated gene encoding the sigma factor pvdS, but it had decreased pyocyanin production. AlgR specifically bound to the prrf2 and pvdS promoters in vitro AlgR-dependent pyoverdine production was additionally influenced by carbon source rather than the extracellular iron concentration per se AlgR phosphorylation effects were also examined in a Drosophila melanogaster feeding, murine acute pneumonia, and punch wound infection models. Abrogation of AlgR phosphorylation attenuated P. aeruginosa virulence in these infection models. These results show that the AlgR phosphorylation state can directly, as well as indirectly, modulate the expression of iron acquisition genes that may ultimately impact the ability of P. aeruginosa to establish and maintain an infection.IMPORTANCE Pyoverdine and pyocyanin production are well-known P. aeruginosa virulence factors that obtain extracellular iron from the environment and from host proteins in different manners. Here, we show that the AlgR phosphorylation state inversely controls pyoverdine and pyocyanin production and that this control is carbon source dependent. P. aeruginosa expressing AlgR D54N, mimicking the constitutively unphosphorylated state, produced more pyocyanin than cells expressing wild-type AlgR. In contrast, a strain expressing an AlgR phosphomimetic (AlgR D54E) produced higher levels of pyoverdine. Pyoverdine production was directly controlled through the prrf2 small regulatory RNA and the pyoverdine sigma factor, PvdS. Abrogating pyoverdine or pyocyanin gene expression has been shown to attenuate virulence in a variety of models. Moreover, the inability to phosphorylate AlgR attenuates virulence in three different models, a Drosophila melanogaster feeding model, a murine acute pneumonia model, and a wound infection model. Interestingly, AlgR-dependent pyoverdine production was responsive to carbon source, indicating that this regulation has additional complexities that merit further study.
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Affiliation(s)
- Alexander S. Little
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Yuta Okkotsu
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Alexandria A. Reinhart
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - F. Heath Damron
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, West Virginia, USA
| | - Mariette Barbier
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, West Virginia, USA
| | - Brandon Barrett
- Department of Biology, University of Dallas, Irving, Texas, USA
| | - Amanda G. Oglesby-Sherrouse
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Joanna B. Goldberg
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
- Center for Cystic Fibrosis and Airways Disease Research, Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
| | - William L. Cody
- Department of Biology, University of Dallas, Irving, Texas, USA
| | - Michael J. Schurr
- Department of Surgery, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Michael L. Vasil
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Michael J. Schurr
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
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Kang D, Turner KE, Kirienko NV. PqsA Promotes Pyoverdine Production via Biofilm Formation. Pathogens 2017; 7:pathogens7010003. [PMID: 29295589 PMCID: PMC5874729 DOI: 10.3390/pathogens7010003] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/18/2017] [Accepted: 12/22/2017] [Indexed: 01/03/2023] Open
Abstract
Biofilms create an impermeable barrier against antimicrobial treatment and immune cell access, severely complicating treatment and clearance of nosocomial Pseudomonas aeruginosa infections. We recently reported that biofilm also contributes to pathogen virulence by regulating the production of the siderophore pyoverdine. In this study, we investigated the role of PqsA, a key cell-signaling protein, in this regulatory pathway. We demonstrate that PqsA promotes pyoverdine production in a biofilm-dependent manner. Under nutritionally deficient conditions, where biofilm and pyoverdine are decoupled, PqsA is dispensable for pyoverdine production. Interestingly, although PqsA-dependent pyoverdine production does not rely upon Pseudomonas quinolone signal (PQS) biosynthesis, exogenous PQS can also trigger biofilm-independent production of pyoverdine. Adding PQS rapidly induced planktonic cell aggregation. Moreover, these clumps of cells exhibit strong expression of pyoverdine biosynthetic genes and show substantial production of this siderophore. Finally, we surveyed the relationship between biofilm formation and pyoverdine production in various clinical and environmental isolates of P. aeruginosa to evaluate the clinical significance of targeting biofilm during infections. Our findings implicate PqsA in P. aeruginosa virulence by regulating biofilm formation and pyoverdine production.
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Affiliation(s)
- Donghoon Kang
- Department of Biosciences, Rice University, Houston, TX 77005, USA.
| | - Kelly E Turner
- Department of Biosciences, Rice University, Houston, TX 77005, USA.
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Heacock-Kang Y, Sun Z, Zarzycki-Siek J, McMillan IA, Norris MH, Bluhm AP, Cabanas D, Fogen D, Vo H, Donachie SP, Borlee BR, Sibley CD, Lewenza S, Schurr MJ, Schweizer HP, Hoang TT. Spatial transcriptomes within the Pseudomonas aeruginosa biofilm architecture. Mol Microbiol 2017; 106:976-985. [PMID: 29030956 PMCID: PMC5720903 DOI: 10.1111/mmi.13863] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2017] [Indexed: 01/24/2023]
Abstract
Bacterial cooperative associations and dynamics in biofilm microenvironments are of special interest in recent years. Knowledge of localized gene‐expression and corresponding bacterial behaviors within the biofilm architecture at a global scale has been limited, due to a lack of robust technology to study limited number of cells in stratified layers of biofilms. With our recent pioneering developments in single bacterial cell transcriptomic analysis technology, we generated herein an unprecedented spatial transcriptome map of the mature in vitro Pseudomonas aeruginosa biofilm model, revealing contemporaneous yet altered bacterial behaviors at different layers within the biofilm architecture (i.e., surface, middle and interior of the biofilm). Many genes encoding unknown functions were highly expressed at the biofilm‐solid interphase, exposing a critical gap in the knowledge of their activities that may be unique to this interior niche. Several genes of unknown functions are critical for biofilm formation. The in vivo importance of these unknown proteins was validated in invertebrate (fruit fly) and vertebrate (mouse) models. We envisage the future value of this report to the community, in aiding the further pathophysiological understanding of P. aeruginosa biofilms. Our approach will open doors to the study of bacterial functional genomics of different species in numerous settings.
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Affiliation(s)
- Yun Heacock-Kang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Zhenxin Sun
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Jan Zarzycki-Siek
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Ian A McMillan
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA.,Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Michael H Norris
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Andrew P Bluhm
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Darlene Cabanas
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Dawson Fogen
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Hung Vo
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Stuart P Donachie
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Bradley R Borlee
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Christopher D Sibley
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Canada
| | - Shawn Lewenza
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Canada
| | - Michael J Schurr
- Department of Immunology and Microbiology, University of Colorado, Aurora, CO, USA
| | - Herbert P Schweizer
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA
| | - Tung T Hoang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA.,Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, USA
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Lufan W, John GSJ, Lynne M. Development of the fly crop vessel bioassay for fly/microbial studies. ACTA ACUST UNITED AC 2017. [DOI: 10.5897/ajmr2017.8586] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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43
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Gupta V, Vasanthakrishnan RB, Siva-Jothy J, Monteith KM, Brown SP, Vale PF. The route of infection determines Wolbachia antibacterial protection in Drosophila. Proc Biol Sci 2017; 284:20170809. [PMID: 28592678 PMCID: PMC5474083 DOI: 10.1098/rspb.2017.0809] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 05/12/2017] [Indexed: 12/03/2022] Open
Abstract
Bacterial symbionts are widespread among metazoans and provide a range of beneficial functions. Wolbachia-mediated protection against viral infection has been extensively demonstrated in Drosophila. In mosquitoes that are artificially transinfected with Drosophila melanogaster Wolbachia (wMel), protection from both viral and bacterial infections has been demonstrated. However, no evidence for Wolbachia-mediated antibacterial protection has been demonstrated in Drosophila to date. Here, we show that the route of infection is key for Wolbachia-mediated antibacterial protection. Drosophila melanogaster carrying Wolbachia showed reduced mortality during enteric-but not systemic-infection with the opportunist pathogen Pseudomonas aeruginosaWolbachia-mediated protection was more pronounced in male flies and is associated with increased early expression of the antimicrobial peptide Attacin A, and also increased expression of a reactive oxygen species detoxification gene (Gst D8). These results highlight that the route of infection is important for symbiont-mediated protection from infection, that Wolbachia can protect hosts by eliciting a combination of resistance and disease tolerance mechanisms, and that these effects are sexually dimorphic. We discuss the importance of using ecologically relevant routes of infection to gain a better understanding of symbiont-mediated protection.
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Affiliation(s)
- Vanika Gupta
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | | | - Jonathon Siva-Jothy
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Katy M Monteith
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Sam P Brown
- School of Biology, Georgia Institute of Technology, Atlanta, GA 30332-0230, USA
| | - Pedro F Vale
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh EH9 3FL, UK
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Regulation of acetyl-CoA synthetase transcription by the CrbS/R two-component system is conserved in genetically diverse environmental pathogens. PLoS One 2017; 12:e0177825. [PMID: 28542616 PMCID: PMC5436829 DOI: 10.1371/journal.pone.0177825] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/03/2017] [Indexed: 12/04/2022] Open
Abstract
The CrbS/R two-component signal transduction system is a conserved regulatory mechanism through which specific Gram-negative bacteria control acetate flux into primary metabolic pathways. CrbS/R governs expression of acetyl-CoA synthase (acsA), an enzyme that converts acetate to acetyl-CoA, a metabolite at the nexus of the cell’s most important energy-harvesting and biosynthetic reactions. During infection, bacteria can utilize this system to hijack host acetate metabolism and alter the course of colonization and pathogenesis. In toxigenic strains of Vibrio cholerae, CrbS/R-dependent expression of acsA is required for virulence in an arthropod model. Here, we investigate the function of the CrbS/R system in Pseudomonas aeruginosa, Pseudomonas entomophila, and non-toxigenic V. cholerae strains. We demonstrate that its role in acetate metabolism is conserved; this system regulates expression of the acsA gene and is required for growth on acetate as a sole carbon source. As a first step towards describing the mechanism of signaling through this pathway, we identify residues and domains that may be critical for phosphotransfer. We further demonstrate that although CrbS, the putative hybrid sensor kinase, carries both a histidine kinase domain and a receiver domain, the latter is not required for acsA transcription. In order to determine whether our findings are relevant to pathogenesis, we tested our strains in a Drosophila model of oral infection previously employed for the study of acetate-dependent virulence by V. cholerae. We show that non-toxigenic V. cholerae strains lacking CrbS or CrbR are significantly less virulent than are wild-type strains, while P. aeruginosa and P. entomophila lacking CrbS or CrbR are fully pathogenic. Together, the data suggest that the CrbS/R system plays a central role in acetate metabolism in V. cholerae, P. aeruginosa, and P. entomophila. However, each microbe’s unique environmental adaptations and pathogenesis strategies may dictate conditions under which CrbS/R-mediated acs expression is most critical.
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Exopolysaccharide-Repressing Small Molecules with Antibiofilm and Antivirulence Activity against Pseudomonas aeruginosa. Antimicrob Agents Chemother 2017; 61:AAC.01997-16. [PMID: 28223377 DOI: 10.1128/aac.01997-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 02/11/2017] [Indexed: 11/20/2022] Open
Abstract
Biofilm formation is a universal virulence strategy in which bacteria grow in dense microbial communities enmeshed within a polymeric extracellular matrix that protects them from antibiotic exposure and the immune system. Pseudomonas aeruginosa is an archetypal biofilm-forming organism that utilizes a biofilm growth strategy to cause chronic lung infections in cystic fibrosis (CF) patients. The extracellular matrix of P. aeruginosa biofilms is comprised mainly of exopolysaccharides (EPS) and DNA. Both mucoid and nonmucoid isolates of P. aeruginosa produce the Pel and Psl EPS, each of which have important roles in antibiotic resistance, biofilm formation, and immune evasion. Given the central importance of the EPS for biofilms, they are attractive targets for novel anti-infective compounds. In this study, we used a high-throughput gene expression screen to identify compounds that repress expression of the pel genes. The pel repressors demonstrated antibiofilm activity against microplate and flow chamber biofilms formed by wild-type and hyperbiofilm-forming strains. To determine the potential role of EPS in virulence, pel/psl mutants were shown to have reduced virulence in feeding behavior and slow killing virulence assays in Caenorhabditis elegans The antibiofilm molecules also reduced P. aeruginosa PAO1 virulence in the nematode slow killing model. Importantly, the combination of antibiotics and antibiofilm compounds increased killing of P. aeruginosa biofilms. These small molecules represent a novel anti-infective strategy for the possible treatment of chronic P. aeruginosa infections.
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Wang JB, Lu HL, St. Leger RJ. The genetic basis for variation in resistance to infection in the Drosophila melanogaster genetic reference panel. PLoS Pathog 2017; 13:e1006260. [PMID: 28257468 PMCID: PMC5352145 DOI: 10.1371/journal.ppat.1006260] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/15/2017] [Accepted: 02/24/2017] [Indexed: 01/01/2023] Open
Abstract
Individuals vary extensively in the way they respond to disease but the genetic basis of this variation is not fully understood. We found substantial individual variation in resistance and tolerance to the fungal pathogen Metarhizium anisopliae Ma549 using the Drosophila melanogaster Genetic Reference Panel (DGRP). In addition, we found that host defense to Ma549 was correlated with defense to the bacterium Pseudomonas aeruginosa Pa14, and several previously published DGRP phenotypes including oxidative stress sensitivity, starvation stress resistance, hemolymph glucose levels, and sleep indices. We identified polymorphisms associated with differences between lines in both their mean survival times and microenvironmental plasticity, suggesting that lines differ in their ability to adapt to variable pathogen exposures. The majority of polymorphisms increasing resistance to Ma549 were sex biased, located in non-coding regions, had moderately large effect and were rare, suggesting that there is a general cost to defense. Nevertheless, host defense was not negatively correlated with overall longevity and fecundity. In contrast to Ma549, minor alleles were concentrated in the most Pa14-susceptible as well as the most Pa14-resistant lines. A pathway based analysis revealed a network of Pa14 and Ma549-resistance genes that are functionally connected through processes that encompass phagocytosis and engulfment, cell mobility, intermediary metabolism, protein phosphorylation, axon guidance, response to DNA damage, and drug metabolism. Functional testing with insertional mutagenesis lines indicates that 12/13 candidate genes tested influence susceptibility to Ma549. Many candidate genes have homologs identified in studies of human disease, suggesting that genes affecting variation in susceptibility are conserved across species.
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Affiliation(s)
- Jonathan B. Wang
- Department of Entomology, University of Maryland College Park, College Park, Maryland, United States of America
| | - Hsiao-Ling Lu
- Department of Entomology, University of Maryland College Park, College Park, Maryland, United States of America
| | - Raymond J. St. Leger
- Department of Entomology, University of Maryland College Park, College Park, Maryland, United States of America
- * E-mail:
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Bergman P, Seyedoleslami Esfahani S, Engström Y. Drosophila as a Model for Human Diseases—Focus on Innate Immunity in Barrier Epithelia. Curr Top Dev Biol 2017; 121:29-81. [DOI: 10.1016/bs.ctdb.2016.07.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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48
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Kim K, Hung RJ, Perrimon N. miR-263a Regulates ENaC to Maintain Osmotic and Intestinal Stem Cell Homeostasis in Drosophila. Dev Cell 2016; 40:23-36. [PMID: 28017617 DOI: 10.1016/j.devcel.2016.11.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 11/04/2016] [Accepted: 11/26/2016] [Indexed: 11/30/2022]
Abstract
Proper regulation of osmotic balance and response to tissue damage is crucial in maintaining intestinal stem cell (ISC) homeostasis. We found that Drosophila miR-263a downregulates the expression of epithelial sodium channel (ENaC) subunits in enterocytes (ECs) to maintain osmotic and ISC homeostasis. In the absence of miR-263a, the intraluminal surface of the intestine displays dehydration-like phenotypes, Na+ levels are increased in ECs, stress pathways are activated in ECs, and ISCs overproliferate. Furthermore, miR-263a mutants have increased bacterial load and expression of antimicrobial peptides. Strikingly, these phenotypes are reminiscent of the pathophysiology of cystic fibrosis (CF) in which loss-of-function mutations in the chloride channel CF transmembrane conductance regulator can elevate the activity of ENaC, suggesting that Drosophila could be used as a model for CF. Finally, we provide evidence that overexpression of miR-183, the human ortholog of miR-263a, can also directly target the expressions of all three subunits of human ENaC.
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Affiliation(s)
- Kevin Kim
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
| | - Ruei-Jiun Hung
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA.
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Martínez E, Campos-Gómez J. Oxylipins produced by Pseudomonas aeruginosa promote biofilm formation and virulence. Nat Commun 2016; 7:13823. [PMID: 27929111 PMCID: PMC5155153 DOI: 10.1038/ncomms13823] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 11/02/2016] [Indexed: 01/14/2023] Open
Abstract
The oxygenation of unsaturated fatty acids by dioxygenases occurs in all kingdoms of life and produces physiologically important lipids called oxylipins. The biological roles of oxylipins have been extensively studied in animals, plants, algae and fungi, but remain largely unidentified in prokaryotes. The bacterium Pseudomonas aeruginosa displays a diol synthase activity that transforms several monounsaturated fatty acids into mono- and di-hydroxylated derivatives. Here we show that oxylipins derived from this activity inhibit flagellum-driven motility and upregulate type IV pilus-dependent twitching motility of P. aeruginosa. Consequently, these oxylipins promote bacterial organization in microcolonies, increasing the ability of P. aeruginosa to form biofilms in vitro and in vivo (in Drosophila flies). We also demonstrate that oxylipins produced by P. aeruginosa promote virulence in Drosophila flies and lettuce. Our study thus uncovers a role for prokaryotic oxylipins in the physiology and pathogenicity of bacteria.
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Affiliation(s)
- Eriel Martínez
- Southern Research, Department of Infectious Diseases, Drug Discovery Division, 2000 Ninth Ave South, Birmingham, Alabama 35205, USA
| | - Javier Campos-Gómez
- Southern Research, Department of Infectious Diseases, Drug Discovery Division, 2000 Ninth Ave South, Birmingham, Alabama 35205, USA
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50
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Mistry R, Kounatidis I, Ligoxygakis P. Exploring interactions between pathogens and the Drosophila gut. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 64:3-10. [PMID: 26876781 DOI: 10.1016/j.dci.2016.01.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 01/19/2016] [Accepted: 01/26/2016] [Indexed: 06/05/2023]
Abstract
Gastrointestinal infection can provoke substantial disturbance at both a local as well as at a systemic level and may evolve into a chronic disease state. Our growing knowledge of gut-pathogen interactions has been based to a large extent on the use of genetically tractable model hosts such as the fruit fly Drosophila melanogaster. In this review we will summarise the growing literature and critically address the advantages and disadvantages of using this model to extrapolate results from studying pathogen virulence and intestinal responses to humans.
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Affiliation(s)
- Rupal Mistry
- Cell Biology, Development and Genetics Lab, Department of Biochemistry, University of Oxford, South Park Rd, OX1 3QU Oxford, UK
| | - Ilias Kounatidis
- Cell Biology, Development and Genetics Lab, Department of Biochemistry, University of Oxford, South Park Rd, OX1 3QU Oxford, UK
| | - Petros Ligoxygakis
- Cell Biology, Development and Genetics Lab, Department of Biochemistry, University of Oxford, South Park Rd, OX1 3QU Oxford, UK.
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