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Ferrarini MG, Vallier A, Vincent-Monégat C, Dell'Aglio E, Gillet B, Hughes S, Hurtado O, Condemine G, Zaidman-Rémy A, Rebollo R, Parisot N, Heddi A. Coordination of host and endosymbiont gene expression governs endosymbiont growth and elimination in the cereal weevil Sitophilus spp. MICROBIOME 2023; 11:274. [PMID: 38087390 PMCID: PMC10717185 DOI: 10.1186/s40168-023-01714-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 10/30/2023] [Indexed: 12/18/2023]
Abstract
BACKGROUND Insects living in nutritionally poor environments often establish long-term relationships with intracellular bacteria that supplement their diets and improve their adaptive and invasive powers. Even though these symbiotic associations have been extensively studied on physiological, ecological, and evolutionary levels, few studies have focused on the molecular dialogue between host and endosymbionts to identify genes and pathways involved in endosymbiosis control and dynamics throughout host development. RESULTS We simultaneously analyzed host and endosymbiont gene expression during the life cycle of the cereal weevil Sitophilus oryzae, from larval stages to adults, with a particular emphasis on emerging adults where the endosymbiont Sodalis pierantonius experiences a contrasted growth-climax-elimination dynamics. We unraveled a constant arms race in which different biological functions are intertwined and coregulated across both partners. These include immunity, metabolism, metal control, apoptosis, and bacterial stress response. CONCLUSIONS The study of these tightly regulated functions, which are at the center of symbiotic regulations, provides evidence on how hosts and bacteria finely tune their gene expression and respond to different physiological challenges constrained by insect development in a nutritionally limited ecological niche. Video Abstract.
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Affiliation(s)
- Mariana Galvão Ferrarini
- Univ Lyon, INSA Lyon, INRAE, BF2I, UMR 203, 69621, Villeurbanne, France
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622, Villeurbanne, France
| | - Agnès Vallier
- Univ Lyon, INRAE, INSA Lyon, BF2I, UMR 203, 69621, Villeurbanne, France
| | | | - Elisa Dell'Aglio
- Univ Lyon, INSA Lyon, INRAE, BF2I, UMR 203, 69621, Villeurbanne, France
| | - Benjamin Gillet
- Institut de Génomique Fonctionnelle de Lyon (IGFL), CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Université de Lyon, Lyon, France
| | - Sandrine Hughes
- Institut de Génomique Fonctionnelle de Lyon (IGFL), CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Université de Lyon, Lyon, France
| | - Ophélie Hurtado
- Univ Lyon, INSA Lyon, INRAE, BF2I, UMR 203, 69621, Villeurbanne, France
| | - Guy Condemine
- Univ Lyon, Université Lyon 1, INSA de Lyon, CNRS UMR 5240 Microbiologie Adaptation et Pathogénie, Villeurbanne, France
| | - Anna Zaidman-Rémy
- Univ Lyon, INSA Lyon, INRAE, BF2I, UMR 203, 69621, Villeurbanne, France
- Institut universitaire de France (IUF), Paris, France
| | - Rita Rebollo
- Univ Lyon, INRAE, INSA Lyon, BF2I, UMR 203, 69621, Villeurbanne, France
| | - Nicolas Parisot
- Univ Lyon, INSA Lyon, INRAE, BF2I, UMR 203, 69621, Villeurbanne, France.
| | - Abdelaziz Heddi
- Univ Lyon, INSA Lyon, INRAE, BF2I, UMR 203, 69621, Villeurbanne, France.
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2
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Ingham CS, Engl T, Matarrita-Carranza B, Vogler P, Huettel B, Wielsch N, Svatoš A, Kaltenpoth M. Host hydrocarbons protect symbiont transmission from a radical host defense. Proc Natl Acad Sci U S A 2023; 120:e2302721120. [PMID: 37487102 PMCID: PMC10400980 DOI: 10.1073/pnas.2302721120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 06/06/2023] [Indexed: 07/26/2023] Open
Abstract
Symbioses with microbes play a pivotal role in the evolutionary success of insects, and can lead to intimate host-symbiont associations. However, how the host maintains a stable symbiosis with its beneficial partners while keeping antagonistic microbes in check remains incompletely understood. Here, we uncover a mechanism by which a host protects its symbiont from the host's own broad-range antimicrobial defense during transmission. Beewolves, a group of solitary digger wasps (Hymenoptera: Crabronidae), provide their brood cells with symbiotic Streptomyces bacteria that are later transferred to the cocoon and protect the offspring from opportunistic pathogens by producing antibiotics. In the brood cell, however, the symbiont-containing secretion is exposed to a toxic burst of nitric oxide (NO) released by the beewolf egg, which effectively kills antagonistic microorganisms. How the symbiont survives this lethal NO burst remained unknown. Here, we report that upon NO exposure in vitro, the symbionts mount a global stress response, but this is insufficient to ensure survival at brood cell-level NO concentrations. Instead, in vivo bioassays demonstrate that the host's antennal gland secretion (AGS) surrounding the symbionts in the brood cell provides an effective diffusion barrier against NO. This physicochemical protection can be reconstituted in vitro by beewolf hydrocarbon extracts and synthetic hydrocarbons, indicating that the host-derived long-chain alkenes and alkanes in the AGS are responsible for shielding the symbionts from NO. Our results reveal how host adaptations can protect a symbiont from host-generated oxidative and nitrosative stress during transmission, thereby efficiently balancing pathogen defense and mutualism maintenance.
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Affiliation(s)
- Chantal Selina Ingham
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg-University Mainz, Mainz55128, Germany
| | - Tobias Engl
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg-University Mainz, Mainz55128, Germany
- Department of Insect Symbiosis, Max-Planck-Institute for Chemical Ecology, Jena07745, Germany
| | | | - Paul Vogler
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg-University Mainz, Mainz55128, Germany
| | - Bruno Huettel
- Max Planck Genome Centre Cologne, Max Planck Institute for Plant Breeding Research, Cologne50829, Germany
| | - Natalie Wielsch
- Research Group Mass Spectrometry/Proteomics, Max-Planck-Institute for Chemical Ecology, Jena07745, Germany
| | - Aleš Svatoš
- Research Group Mass Spectrometry/Proteomics, Max-Planck-Institute for Chemical Ecology, Jena07745, Germany
| | - Martin Kaltenpoth
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg-University Mainz, Mainz55128, Germany
- Department of Insect Symbiosis, Max-Planck-Institute for Chemical Ecology, Jena07745, Germany
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3
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Peng J, Xu Z, Li L, Zhao B, Guo Y. Disruption of the sensor kinase phoQ gene decreases acid resistance in plant growth-promoting rhizobacterium Rahnella aquatilis HX2. J Appl Microbiol 2023; 134:6991427. [PMID: 36748653 DOI: 10.1093/jambio/lxad009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/24/2022] [Accepted: 01/17/2023] [Indexed: 01/20/2023]
Abstract
AIMS Rahnella aquatilis HX2, a promising plant growth-promoting rhizobacterium (PGPR) in the field, contains genes homologous to the PhoP/PhoQ two-component regulatory system. Although this system regulates stress response in numerous pathogens, PhoP/PhoQ characterization in a PGPR has not received in-depth exploration. METHODS AND RESULTS The phoQ gene was mutated in strain HX2 using an in-frame deletion strategy. Compared to the wild type, the phoQ mutant exhibited increased sensitivity to acidic conditions (pH 4.0) in a chemically defined medium and in mild acidic natural soil (pH 5.7). The phoQ mutant also exhibited increased swimming motility under acidic conditions. Acid resistance was restored in the mutant by introducing the phoQ gene on a plasmid. Three acid resistance genes, add, cfa, and fur were downregulated significantly, whereas the chaperone encoding gene, dnak, was upregulated when the phoQ mutant was exposed to acid stress. CONCLUSIONS This study suggested that the PhoP/PhoQ system positively regulates the acid resistance of R. aquatilis HX2.
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Affiliation(s)
- Jing Peng
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.,Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Zhongnan Xu
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.,Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Lei Li
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.,Institute of Vegetables and Flowers, Chinese Academy of Agricultural Science, Beijing 100081, China
| | - Bingjie Zhao
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.,Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Yanbin Guo
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.,Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
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4
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Ganesan R, Wierz JC, Kaltenpoth M, Flórez LV. How It All Begins: Bacterial Factors Mediating the Colonization of Invertebrate Hosts by Beneficial Symbionts. Microbiol Mol Biol Rev 2022; 86:e0012621. [PMID: 36301103 PMCID: PMC9769632 DOI: 10.1128/mmbr.00126-21] [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: 01/01/2023] Open
Abstract
Beneficial associations with bacteria are widespread across animals, spanning a range of symbiont localizations, transmission routes, and functions. While some of these associations have evolved into obligate relationships with permanent symbiont localization within the host, the majority require colonization of every host generation from the environment or via maternal provisions. Across the broad diversity of host species and tissue types that beneficial bacteria can colonize, there are some highly specialized strategies for establishment yet also some common patterns in the molecular basis of colonization. This review focuses on the mechanisms underlying the early stage of beneficial bacterium-invertebrate associations, from initial contact to the establishment of the symbionts in a specific location of the host's body. We first reflect on general selective pressures that can drive the transition from a free-living to a host-associated lifestyle in bacteria. We then cover bacterial molecular factors for colonization in symbioses from both model and nonmodel invertebrate systems where these have been studied, including terrestrial and aquatic host taxa. Finally, we discuss how interactions between multiple colonizing bacteria and priority effects can influence colonization. Taking the bacterial perspective, we emphasize the importance of developing new experimentally tractable systems to derive general insights into the ecological factors and molecular adaptations underlying the origin and establishment of beneficial symbioses in animals.
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Affiliation(s)
- Ramya Ganesan
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Jürgen C. Wierz
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Martin Kaltenpoth
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Laura V. Flórez
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Plant and Environmental Sciences, Section for Organismal Biology, University of Copenhagen, Copenhagen, Denmark
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5
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Brunetti AE, Bunk B, Lyra ML, Fuzo CA, Marani MM, Spröer C, Haddad CFB, Lopes NP, Overmann J. Molecular basis of a bacterial-amphibian symbiosis revealed by comparative genomics, modeling, and functional testing. THE ISME JOURNAL 2022; 16:788-800. [PMID: 34601502 PMCID: PMC8857215 DOI: 10.1038/s41396-021-01121-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 09/15/2021] [Accepted: 09/16/2021] [Indexed: 02/08/2023]
Abstract
The molecular bases for the symbiosis of the amphibian skin microbiome with its host are poorly understood. Here, we used the odor-producer Pseudomonas sp. MPFS and the treefrog Boana prasina as a model to explore bacterial genome determinants and the resulting mechanisms facilitating symbiosis. Pseudomonas sp. MPFS and its closest relatives, within a new clade of the P. fluoresens Group, have large genomes and were isolated from fishes and plants, suggesting environmental plasticity. We annotated 16 biosynthetic gene clusters from the complete genome sequence of this strain, including those encoding the synthesis of compounds with known antifungal activity and of odorous methoxypyrazines that likely mediate sexual interactions in Boana prasina. Comparative genomics of Pseudomonas also revealed that Pseudomonas sp. MPFS and its closest relatives have acquired specific resistance mechanisms against host antimicrobial peptides (AMPs), specifically two extra copies of a multidrug efflux pump and the same two-component regulatory systems known to trigger adaptive resistance to AMPs in P. aeruginosa. Subsequent molecular modeling indicated that these regulatory systems interact with an AMP identified in Boana prasina through the highly acidic surfaces of the proteins comprising their sensory domains. In agreement with a symbiotic relationship and a highly selective antibacterial function, this AMP did not inhibit the growth of Pseudomonas sp. MPFS but inhibited the growth of another Pseudomonas species and Escherichia coli in laboratory tests. This study provides deeper insights into the molecular interaction of the bacteria-amphibian symbiosis and highlights the role of specific adaptive resistance toward AMPs of the hosts.
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Affiliation(s)
- Andrés E. Brunetti
- grid.11899.380000 0004 1937 0722Departamento de Ciências Biomoleculares, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903 Ribeirão Preto, SP Brazil ,grid.412223.40000 0001 2179 8144Laboratorio de Genética Evolutiva, Instituto de Biología Subtropical (CONICET – UNaM), Facultad de Ciencias Exactas, Universidad Nacional de Misiones, N3300 Posadas, Argentina
| | - Boyke Bunk
- grid.420081.f0000 0000 9247 8466Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, 38124 Braunschweig, Germany
| | - Mariana L. Lyra
- grid.410543.70000 0001 2188 478XDepartamento de Biodiversidade e Centro de Aquicultura, Instituto de Biociências, Universidade Estadual Paulista, 13506-900 Rio Claro, SP Brazil
| | - Carlos A. Fuzo
- grid.11899.380000 0004 1937 0722Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903 Ribeirão Preto, SP Brazil
| | - Mariela M. Marani
- grid.423606.50000 0001 1945 2152IPEEC-CONICET, Instituto Patagónico para el Estudio de los Ecosistemas Continentales, Consejo Nacional de Investigaciones Científicas y Técnicas, U9120ACD Puerto Madryn, Argentina
| | - Cathrin Spröer
- grid.420081.f0000 0000 9247 8466Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, 38124 Braunschweig, Germany
| | - Célio F. B. Haddad
- grid.410543.70000 0001 2188 478XDepartamento de Biodiversidade e Centro de Aquicultura, Instituto de Biociências, Universidade Estadual Paulista, 13506-900 Rio Claro, SP Brazil
| | - Norberto P. Lopes
- grid.11899.380000 0004 1937 0722Departamento de Ciências Biomoleculares, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903 Ribeirão Preto, SP Brazil
| | - Jörg Overmann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, 38124, Braunschweig, Germany. .,Mikrobiologie, Technische Universität Braunschweig, 38106, Braunschweig, Germany.
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6
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Abstract
Mg2+ is the most abundant divalent cation in living cells. It is essential for charge neutralization, macromolecule stabilization, and the assembly and activity of ribosomes and as a cofactor for enzymatic reactions. When experiencing low cytoplasmic Mg2+, bacteria adopt two main strategies: They increase the abundance and activity of Mg2+ importers and decrease the abundance of Mg2+-chelating ATP and rRNA. These changes reduce regulated proteolysis by ATP-dependent proteases and protein synthesis in a systemic fashion. In many bacterial species, the transcriptional regulator PhoP controls expression of proteins mediating these changes. The 5' leader region of some mRNAs responds to low cytoplasmic Mg2+ or to disruptions in translation of open reading frames in the leader regions by furthering expression of the associated coding regions, which specify proteins mediating survival when the cytoplasmic Mg2+ concentration is low. Microbial species often utilize similar adaptation strategies to cope with low cytoplasmic Mg2+ despite relying on different genes to do so.
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Affiliation(s)
- Eduardo A Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut 06536, USA; .,Yale Microbial Sciences Institute, West Haven, Connecticut 06516, USA
| | - Carissa Chan
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut 06536, USA;
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7
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Shprung T, Wani NA, Wilmes M, Mangoni ML, Bitler A, Shimoni E, Sahl HG, Shai Y. Opposing Effects of PhoPQ and PmrAB on the Properties of Salmonella enterica serovar Typhimurium: Implications on Resistance to Antimicrobial Peptides. Biochemistry 2021; 60:2943-2955. [PMID: 34547893 PMCID: PMC8638962 DOI: 10.1021/acs.biochem.1c00287] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The increasing number of resistant
bacteria is a major threat worldwide,
leading to the search for new antibiotic agents. One of the leading
strategies is the use of antimicrobial peptides (AMPs), cationic and
hydrophobic innate immune defense peptides. A major target of AMPs
is the bacterial membrane. Notably, accumulating data suggest that
AMPs can activate the two-component systems (TCSs) of Gram-negative
bacteria. These include PhoP-PhoQ (PhoPQ) and PmrA-PmrB (PmrAB), responsible
for remodeling of the bacterial cell surface. To better understand
this mechanism, we utilized bacteria deficient either in one system
alone or in both and biophysical tools including fluorescence spectroscopy,
single-cell atomic force microscopy, electron microscopy, and mass
spectrometry (MoskowitzS. M.;Antimicrob. Agents Chemother.2012, 56, 1019−103022106224; ChengH. Y.;J. Biomed. Sci.2010, 17, 6020653976). Our data suggested that the two systems have opposing
effects on the properties of Salmonella enterica. The knockout of PhoPQ made the bacteria more susceptible to AMPs
by making the surface less rigid, more polarized, and permeable with
a slightly more negatively charged cell wall. In addition, the periplasmic
space is thinner. In contrast, the knockout of PmrAB did not affect
its susceptibility, while it made the bacterial outer layer very rigid,
less polarized, and less permeable than the other two mutants, with
a negatively charged cell wall similar to the WT. Overall, the data
suggest that the coexistence of systems with opposing effects on the
biophysical properties of the bacteria contribute to their membrane
flexibility, which, on the one hand, is important to accommodate changing
environments and, on the other hand, may inhibit the development of
meaningful resistance to AMPs.
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Affiliation(s)
- Tal Shprung
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Naiem Ahmad Wani
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Miriam Wilmes
- Pharmaceutical Microbiology Section, Institute for Medical Microbiology, Immunology and Parasitology, University of Bonn, Sigmund-Freud-Strasse 25, D-53127 Bonn, Germany
| | - Maria Luisa Mangoni
- Department of Biochemical Sciences A. Rossi Fanelli, Faculty of Pharmacy and Medicine, Sapienza University of Rome, CU27, 00185 Roma, Italy
| | - Arkadi Bitler
- Department of Chemical Research Support, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Eyal Shimoni
- Department of Chemical Research Support, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Hans-Georg Sahl
- Pharmaceutical Microbiology Section, Institute for Medical Microbiology, Immunology and Parasitology, University of Bonn, Sigmund-Freud-Strasse 25, D-53127 Bonn, Germany
| | - Yechiel Shai
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
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8
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Sayed M, Ozdemir O, Essa M, Olivier A, Karsi A, Lawrence ML, Abdelhamed H. Virulence and live vaccine potential of Edwardsiella piscicida phoP and phoQ mutants in catfish against edwardsiellosis. JOURNAL OF FISH DISEASES 2021; 44:1463-1474. [PMID: 34037985 DOI: 10.1111/jfd.13453] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 06/12/2023]
Abstract
Edwardsiella piscicida is a Gram-negative facultative intracellular bacterium causing edwardsiellosis in catfish, the largest aquaculture industry in the United States. A safe and effective vaccine is an urgent need to avoid economic losses associated with E. piscicida outbreaks. PhoP/PhoQ is a two-component signal transduction system (TCS) that plays an important role in bacterial pathogenesis through sense and response to environmental and host stress signals. This study aimed to explore the contribution of PhoQ/PhoP in E. piscicida virulence and develop live attenuated vaccines against E. piscicida infection in channel catfish (Ictalurus punctatus) and hybrid catfish (channel catfish ♀ × blue catfish (I. furcatus) ♂). In the current study, two in-frame deletion mutants were constructed by deleting phoP (ETAC_09785) and phoQ (ETAC_09790) genes in E. piscicida strain C07-087, and the virulence and protection efficacy of the constructed strains were evaluated in catfish following intraperitoneal injection. Both EpΔphoP and EpΔphoQ strains had a delayed adaptation to oxidative stress (0.2% H2 O2 ) compared to E. piscicida wild type. The EpΔphoP and EpΔphoQ mutants produced significantly less biofilm compared to wild-type E. piscicida. Notably, EpΔphoP and EpΔphoQ mutants were significantly attenuated in channel catfish compared with wild-type E. piscicida (6.63% and 4.17% versus 49.16% mortalities), and channel catfish vaccinated with EpΔphoP and EpΔphoQ were significantly protected (95.65% and 97.92% survival) against E. piscicida infection at 21 days post-vaccination. In hybrid catfish, EpΔphoP was significantly more attenuated than EpΔphoQ, but EpΔphoQ provided significantly better protection than EpΔphoP. EpΔphoP and EpΔphoQ strains both induced specific antibodies in channel catfish against E. piscicida at 14 and 21 days post-vaccination. This result indicated that EpΔphoP and EpΔphoQ mutants were safe and protective in channel catfish fingerlings, while EpΔphoP was safe in hybrid catfish. Our findings show that PhoP and PhoQ are required for adaptation to oxidative stress and biofilm formation and may help E. piscicida face tough environmental challenges; thus, functional PhoP and PhoQ are critical for a successful infection.
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Affiliation(s)
- Mohamed Sayed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
- Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt
| | - Ozan Ozdemir
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - Manal Essa
- Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt
| | - Alicia Olivier
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - Attila Karsi
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - Mark L Lawrence
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - Hossam Abdelhamed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
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9
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Groisman EA, Duprey A, Choi J. How the PhoP/PhoQ System Controls Virulence and Mg 2+ Homeostasis: Lessons in Signal Transduction, Pathogenesis, Physiology, and Evolution. Microbiol Mol Biol Rev 2021; 85:e0017620. [PMID: 34191587 PMCID: PMC8483708 DOI: 10.1128/mmbr.00176-20] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The PhoP/PhoQ two-component system governs virulence, Mg2+ homeostasis, and resistance to a variety of antimicrobial agents, including acidic pH and cationic antimicrobial peptides, in several Gram-negative bacterial species. Best understood in Salmonella enterica serovar Typhimurium, the PhoP/PhoQ system consists o-regulated gene products alter PhoP-P amounts, even under constant inducing conditions. PhoP-P controls the abundance of hundreds of proteins both directly, by having transcriptional effects on the corresponding genes, and indirectly, by modifying the abundance, activity, or stability of other transcription factors, regulatory RNAs, protease regulators, and metabolites. The investigation of PhoP/PhoQ has uncovered novel forms of signal transduction and the physiological consequences of regulon evolution.
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Affiliation(s)
- Eduardo A. Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
- Yale Microbial Sciences Institute, West Haven, Connecticut, USA
| | - Alexandre Duprey
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Jeongjoon Choi
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
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10
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Wang D, Huang Z, Billen J, Zhang G, He H, Wei C. Structural diversity of symbionts and related cellular mechanisms underlying vertical symbiont transmission in cicadas. Environ Microbiol 2021; 23:6603-6621. [PMID: 34390615 DOI: 10.1111/1462-2920.15711] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 08/05/2021] [Accepted: 08/08/2021] [Indexed: 11/29/2022]
Abstract
Many insects depend on symbiont(s) for survival. This is particularly the case for sap-feeding hemipteran insects. In this study, we revealed that symbionts harbored in cicadas are diverse and complex, and the yeast-like fungal symbionts (YLS) are present in most cicada species but Hodgkinia is absent. During vertical transmission, Sulcia became swollen with the outer membrane drastically changed, while Hodgkinia became shrunken and changed from irregular to roughly spherical. Sulcia and/or Hodgkinia were exocytosed from the bacteriocytes to the intercellular space of bacteriomes, where they gathered together and were extruded to hemolymph. YLS and associated facultative symbiont(s) in the fat bodies were released to the hemolymph based on bacteriocyte disintegration. The obligate symbiont(s) were endocytosed and exocytosed successively by the epithelial cells of the terminal oocyte, while associated facultative symbiont(s), and possibly also YLS, may take a 'free ride' on the transmission of obligate symbiont(s) to gain entry into the oocyte. Then, the intermixed symbionts formed a characteristic 'symbiont ball' in the oocyte. Our results suggest that YLS in cicadas represent a new example of a relatively early stage of symbiogenesis in insects, and contribute to a better understanding of the diversity and transmission mechanisms of symbionts in insects. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Dandan Wang
- Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China.,State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Zhi Huang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, 712100, Shaanxi, China.,Key Laboratory of National Forestry and Grassland Administration for Control of Forest Biological Disasters in Western China, College of Forestry, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Johan Billen
- Zoological Institute, University of Leuven, Naamsestraat 59, B-3000, Leuven, Belgium
| | - Guoyun Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Hong He
- Key Laboratory of National Forestry and Grassland Administration for Control of Forest Biological Disasters in Western China, College of Forestry, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Cong Wei
- Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China.,State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, 712100, Shaanxi, China
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11
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Abstract
Bacteriophages (phages) are ubiquitous in nature. These viruses play a number of central roles in microbial ecology and evolution by, for instance, promoting horizontal gene transfer (HGT) among bacterial species. The ability of phages to mediate HGT through transduction has been widely exploited as an experimental tool for the genetic study of bacteria. As such, bacteriophage P1 represents a prototypical generalized transducing phage with a broad host range that has been extensively employed in the genetic manipulation of Escherichia coli and a number of other model bacterial species. Here we demonstrate that P1 is capable of infecting, lysogenizing, and promoting transduction in members of the bacterial genus Sodalis, including the maternally inherited insect endosymbiont Sodalis glossinidius. While establishing new tools for the genetic study of these bacterial species, our results suggest that P1 may be used to deliver DNA to many Gram-negative endosymbionts in their insect host, thereby circumventing a culturing requirement to genetically manipulate these organisms. IMPORTANCE A large number of economically important insects maintain intimate associations with maternally inherited endosymbiotic bacteria. Due to the inherent nature of these associations, insect endosymbionts cannot be usually isolated in pure culture or genetically manipulated. Here we use a broad-host-range bacteriophage to deliver exogenous DNA to an insect endosymbiont and a closely related free-living species. Our results suggest that broad-host-range bacteriophages can be used to genetically alter insect endosymbionts in their insect host and, as a result, bypass a culturing requirement to genetically alter these bacteria.
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12
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Masson F, Lemaitre B. Growing Ungrowable Bacteria: Overview and Perspectives on Insect Symbiont Culturability. Microbiol Mol Biol Rev 2020; 84:e00089-20. [PMID: 33177190 PMCID: PMC7667007 DOI: 10.1128/mmbr.00089-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Insects are often involved in endosymbiosis, that is, the housing of symbiotic microbes within their tissues or within their cells. Endosymbionts are a major driving force in insects' evolution, because they dramatically affect their host physiology and allow them to adapt to new niches, for example, by complementing their diet or by protecting them against pathogens. Endosymbiotic bacteria are, however, fastidious and therefore difficult to manipulate outside of their hosts, especially intracellular species. The coevolution between hosts and endosymbionts leads to alterations in the genomes of endosymbionts, limiting their ability to cope with changing environments. Consequently, few insect endosymbionts are culturable in vitro and genetically tractable, making functional genetics studies impracticable on most endosymbiotic bacteria. However, recently, major progress has been made in manipulating several intracellular endosymbiont species in vitro, leading to astonishing discoveries on their physiology and the way they interact with their host. This review establishes a comprehensive picture of the in vitro tractability of insect endosymbiotic bacteria and addresses the reason why most species are not culturable. By compiling and discussing the latest developments in the design of custom media and genetic manipulation protocols, it aims at providing new leads to expand the range of tractable endosymbionts and foster genetic research on these models.
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Affiliation(s)
- Florent Masson
- Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Bruno Lemaitre
- Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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13
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Abstract
Host-beneficial endosymbioses, which are formed when a microorganism takes up residence inside another cell and provides a fitness advantage to the host, have had a dramatic influence on the evolution of life. These intimate relationships have yielded the mitochondrion and the plastid (chloroplast) - the ancient organelles that in part define eukaryotic life - along with many more recent associations involving a wide variety of hosts and microbial partners. These relationships are often envisioned as stable associations that appear cooperative and persist for extremely long periods of time. But recent evidence suggests that this stable state is often born from turbulent and conflicting origins, and that the apparent stability of many beneficial endosymbiotic relationships - although certainly real in many cases - is not an inevitable outcome of these associations. Here we review how stable endosymbioses form, how they are maintained, and how they sometimes break down and are reborn. We focus on relationships formed by insects and their resident microorganisms because these symbioses have been the focus of significant empirical work over the last two decades. We review these relationships over five life stages: origin, birth, middle age, old age, and death.
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14
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Roma JS, D’Souza S, Somers PJ, Cabo LF, Farsin R, Aksoy S, Runyen-Janecky LJ, Weiss BL. Thermal stress responses of Sodalis glossinidius, an indigenous bacterial symbiont of hematophagous tsetse flies. PLoS Negl Trop Dis 2019; 13:e0007464. [PMID: 31738754 PMCID: PMC6887450 DOI: 10.1371/journal.pntd.0007464] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 12/02/2019] [Accepted: 10/24/2019] [Indexed: 11/22/2022] Open
Abstract
Tsetse flies (Diptera: Glossinidae) house a taxonomically diverse microbiota that includes environmentally acquired bacteria, maternally transmitted symbiotic bacteria, and pathogenic African trypanosomes. Sodalis glossinidius, which is a facultative symbiont that resides intra and extracellularly within multiple tsetse tissues, has been implicated as a mediator of trypanosome infection establishment in the fly’s gut. Tsetse’s gut-associated population of Sodalis are subjected to marked temperature fluctuations each time their ectothermic fly host imbibes vertebrate blood. The molecular mechanisms that Sodalis employs to deal with this heat stress are unknown. In this study, we examined the thermal tolerance and heat shock response of Sodalis. When grown on BHI agar plates, the bacterium exhibited the most prolific growth at 25oC, and did not grow at temperatures above 30oC. Growth on BHI agar plates at 31°C was dependent on either the addition of blood to the agar or reduction in oxygen levels. Sodalis was viable in liquid cultures for 24 hours at 30oC, but began to die upon further exposure. The rate of death increased with increased temperature. Similarly, Sodalis was able to survive for 48 hours within tsetse flies housed at 30oC, while a higher temperature (37oC) was lethal. Sodalis’ genome contains homologues of the heat shock chaperone protein-encoding genes dnaK, dnaJ, and grpE, and their expression was up-regulated in thermally stressed Sodalis, both in vitro and in vivo within tsetse fly midguts. Arrested growth of E. coli dnaK, dnaJ, or grpE mutants under thermal stress was reversed when the cells were transformed with a low copy plasmid that encoded the Sodalis homologues of these genes. The information contained in this study provides insight into how arthropod vector enteric commensals, many of which mediate their host’s ability to transmit pathogens, mitigate heat shock associated with the ingestion of a blood meal. Microorganisms associated with insects must cope with fluctuating temperatures. Because symbiotic bacteria influence the biology of their host, how they respond to temperature changes will have an impact on the host and other microorganisms in the host. The tsetse fly and its symbionts represent an important model system for studying thermal tolerance because the fly feeds exclusively on vertebrate blood and is thus exposed to dramatic temperature shifts. Tsetse flies house a microbial community that can consist of symbiotic and environmentally acquired bacteria, viruses, and parasitic African trypanosomes. This work, which makes use of tsetse’s commensal endosymbiont, Sodalis glossinidius, is significance because it represents the only examination of thermal tolerance mechanisms in a bacterium that resides indigenously within an arthropod disease vector. A better understanding of the biology of thermal tolerance in Sodalis provides insight into thermal stress survival in other insect symbionts and may yield information to help control vector-borne disease.
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Affiliation(s)
- Jose Santinni Roma
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
| | - Shaina D’Souza
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
| | - Patrick J. Somers
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
| | - Leah F. Cabo
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
| | - Ruhan Farsin
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
| | - Serap Aksoy
- Yale School of Public Health, Department of Epidemiology of Microbial Diseases, New Haven, Connecticut, United States of America
| | - Laura J. Runyen-Janecky
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
- * E-mail: (LJR-J); (BLW)
| | - Brian L. Weiss
- Yale School of Public Health, Department of Epidemiology of Microbial Diseases, New Haven, Connecticut, United States of America
- * E-mail: (LJR-J); (BLW)
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15
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Trappeniers K, Matetovici I, Van Den Abbeele J, De Vooght L. The Tsetse Fly Displays an Attenuated Immune Response to Its Secondary Symbiont, Sodalis glossinidius. Front Microbiol 2019; 10:1650. [PMID: 31396178 PMCID: PMC6668328 DOI: 10.3389/fmicb.2019.01650] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 07/03/2019] [Indexed: 11/13/2022] Open
Abstract
Sodalis glossinidius, a vertically transmitted facultative symbiont of the tsetse fly, is a bacterium in the early/intermediate state of its transition toward symbiosis, representing an important model for investigating how the insect host immune defense response is regulated to allow endosymbionts to establish a chronic infection within their hosts without being eliminated. In this study, we report on the establishment of a tsetse fly line devoid of S. glossinidius only, allowing us to experimentally investigate (i) the complex immunological interactions between a single bacterial species and its host, (ii) how the symbiont population is kept under control, and (iii) the impact of the symbiont on the vector competence of the tsetse fly to transmit the sleeping sickness parasite. Comparative transcriptome analysis showed no difference in the expression of genes involved in innate immune processes between symbiont-harboring (GmmSod+) and S. glossinidius-free (GmmSod–) flies. Re-exposure of (GmmSod–) flies to the endosymbiotic bacterium resulted in a moderate immune response, whereas exposure to pathogenic E. coli or to a close non-insect associated relative of S. glossinidius, i.e., S. praecaptivus, resulted in full immune activation. We also showed that S. glossinidius densities are not affected by experimental activation or suppression of the host immune system, indicating that S. glossinidius is resistant to mounted immune attacks and that the host immune system does not play a major role in controlling S. glossinidius proliferation. Finally, we demonstrate that the absence or presence of S. glossinidius in the tsetse fly does not alter its capacity to mount an immune response to pathogens nor does it affect the fly’s susceptibility toward trypanosome infection.
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Affiliation(s)
- Katrien Trappeniers
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
| | - Irina Matetovici
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
| | - Jan Van Den Abbeele
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
| | - Linda De Vooght
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
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16
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Mergaert P. Role of antimicrobial peptides in controlling symbiotic bacterial populations. Nat Prod Rep 2019; 35:336-356. [PMID: 29393944 DOI: 10.1039/c7np00056a] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Covering: up to 2018 Antimicrobial peptides (AMPs) have been known for well over three decades as crucial mediators of the innate immune response in animals and plants, where they are involved in the killing of infecting microbes. However, AMPs have now also been found to be produced by eukaryotic hosts during symbiotic interactions with bacteria. These symbiotic AMPs target the symbionts and therefore have a more subtle biological role: not eliminating the microbial symbiont population but rather keeping it in check. The arsenal of AMPs and the symbionts' adaptations to resist them are in a careful balance, which contributes to the establishment of the host-microbe homeostasis. Although in many cases the biological roles of symbiotic AMPs remain elusive, for a number of symbiotic interactions, precise functions have been assigned or proposed to the AMPs, which are discussed here. The microbiota living on epithelia in animals, from the most primitive ones to the mammals, are challenged by a cocktail of AMPs that determine the specific composition of the bacterial community as well as its spatial organization. In the symbiosis of legume plants with nitrogen-fixing rhizobium bacteria, the host deploys an extremely large panel of AMPs - called nodule-specific cysteine-rich (NCR) peptides - that drive the bacteria into a terminally differentiated state and manipulate the symbiont physiology to maximize the benefit for the host. The NCR peptides are used as tools to enslave the bacterial symbionts, limiting their reproduction but keeping them metabolically active for nitrogen fixation. In the nutritional symbiotic interactions of insects and protists that have vertically transmitted bacterial symbionts with reduced genomes, symbiotic AMPs could facilitate the integration of the endosymbiont and host metabolism by favouring the flow of metabolites across the symbiont membrane through membrane permeabilization.
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Affiliation(s)
- P Mergaert
- Institute for Integrative Biology of the Cell, UMR9198, CNRS, Université Paris-Sud, CEA, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France.
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17
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Nadal-Jimenez P, Griffin JS, Davies L, Frost CL, Marcello M, Hurst GDD. Genetic manipulation allows in vivo tracking of the life cycle of the son-killer symbiont, Arsenophonus nasoniae, and reveals patterns of host invasion, tropism and pathology. Environ Microbiol 2019; 21:3172-3182. [PMID: 31237728 PMCID: PMC6771839 DOI: 10.1111/1462-2920.14724] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 06/19/2019] [Accepted: 06/21/2019] [Indexed: 12/17/2022]
Abstract
Maternally heritable symbionts are common in arthropods and represent important partners and antagonists. A major impediment to understanding the mechanistic basis of these symbioses has been lack of genetic manipulation tools, for instance, those enabling transgenic GFP expression systems for in vivo visualization. Here, we transform the ‘son‐killer’ reproductive parasite Arsenophonus nasoniae that infects the parasitic wasp Nasonia vitripennis with the plasmid pOM1‐gfp, re‐introduce this strain to N. vitripennis and then used this system to track symbiont life history in vivo. These data revealed transfer of the symbiont into the fly pupa by N. vitripennis during oviposition and N. vitripennis larvae developing infection over time through feeding. A strong tropism of A. nasoniae to the N. vitripennis ovipositor developed during wasp pupation, which aids onward transmission. The symbiont was also visualized in diapause larvae. Occasional necrotic diapause larvae were observed which displayed intense systemic infection alongside widespread melanotic nodules indicative of an active but failed immune response. Our results provide the foundation for the study of this symbiosis through in vivo tracking of the fate of symbionts through host development, which is rarely achieved in heritable microbe/insect interactions.
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Affiliation(s)
- Pol Nadal-Jimenez
- Institute for Integrative Biology, University of Liverpool, Liverpool, UK
| | - Joanne S Griffin
- Institute for Integrative Biology, University of Liverpool, Liverpool, UK
| | - Lianne Davies
- Institute for Integrative Biology, University of Liverpool, Liverpool, UK
| | - Crystal L Frost
- Institute for Integrative Biology, University of Liverpool, Liverpool, UK
| | - Marco Marcello
- Institute for Integrative Biology, University of Liverpool, Liverpool, UK
| | - Gregory D D Hurst
- Institute for Integrative Biology, University of Liverpool, Liverpool, UK
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18
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Established Cotton Stainer Gut Bacterial Mutualists Evade Regulation by Host Antimicrobial Peptides. Appl Environ Microbiol 2019; 85:AEM.00738-19. [PMID: 31028027 DOI: 10.1128/aem.00738-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 04/22/2019] [Indexed: 01/03/2023] Open
Abstract
Symbioses with microorganisms are ubiquitous in nature and confer important ecological traits to animal hosts but also require control mechanisms to ensure homeostasis of the symbiotic interactions. In addition to protecting hosts against pathogens, animal immune systems recognize, respond to, and regulate mutualists. The gut bacterial symbionts of the cotton stainer bug, Dysdercus fasciatus, elicit an immune response characterized by the upregulation of c-type lysozyme and the antimicrobial peptide pyrrhocoricin in bugs with their native gut microbiota compared to that in dysbiotic insects. In this study, we investigated the impact of the elicited antimicrobial immune response on the established cotton stainer gut bacterial symbiont populations. To this end, we used RNA interference (RNAi) to knock down immunity-related genes hypothesized to regulate the symbionts, and we subsequently measured the effect of this silencing on host fitness and on the abundance of the major gut bacterial symbionts. Despite successful downregulation of target genes by both ingestion and injection of double-stranded RNA (dsRNA), the silencing of immunity-related genes had no effect on either host fitness or the qualitative and quantitative composition of established gut bacterial symbionts, indicating that the host immune responses are not actively involved in the regulation of the nutritional and defensive gut bacterial mutualists. These results suggest that close associations of bacterial symbionts with their hosts can result in the evolution of mechanisms ensuring that symbionts remain insensitive to host immunological responses, which may be important for the evolutionary stability of animal-microbe symbiotic associations.IMPORTANCE Animal immune systems are central for the protection of hosts against enemies by preventing or eliminating successful infections. However, in the presence of beneficial bacterial mutualists, the immune system must strike a balance of not killing the beneficial symbionts while at the same time preventing enemy attacks. Here, using the cotton stainer bug, we reveal that its long-term associated bacterial symbionts are insensitive to the host's immune effectors, suggesting adaptation to the host's defenses, thereby strengthening the stability of the symbiotic relationship. The ability of the symbionts to elicit host immune responses but remain insensitive themselves may be a mechanism by which the symbionts prime hosts to fight future pathogenic infections.
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19
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Blow F, Douglas AE. The hemolymph microbiome of insects. JOURNAL OF INSECT PHYSIOLOGY 2019; 115:33-39. [PMID: 30953618 DOI: 10.1016/j.jinsphys.2019.04.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 03/27/2019] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
Hemolymph has long been recognized as a key mediator of nutritional and immunological homeostasis in insects, with the tacit understanding that hemolymph is a hostile environment for microorganisms, and microbiologically sterile in healthy insects. Recent research is overturning the conventional wisdom, and there is now overwhelming evidence that various non-pathogenic microorganisms can stably or transiently inhabit hemolymph in a diversity of insects. Most is known about Spiroplasma, especially in Drosophila species, and secondary symbionts of the Enterobacteriaceae, notably Hamiltonella defensa, in aphids. These bacteria require many nutrients, representing a likely drain on host nutritional resources, and they persist in the hemolymph by a combination of evasion and tolerance of insect immune effectors. These traits can be costly to the insect host. For some hemolymph microorganisms, these costs are balanced by other traits beneficial to the insect, notably protection against natural enemies mediated by specific toxins or competition for key nutrients. Three key priorities for future research are: to investigate the prevalence and taxonomic diversity of hemolymph microorganisms in insects; to establish the role of host nutritional and immune factors as determinants of the abundance and proliferation rates of hemolymph microorganisms; and to integrate the developing understanding of these microorganisms and their impacts (both costs and benefits) on insect nutrition and immune function into the wider study of insect physiology.
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Affiliation(s)
- Frances Blow
- Department of Entomology, Cornell University, Ithaca, NY 14853, USA
| | - Angela E Douglas
- Department of Entomology, Cornell University, Ithaca, NY 14853, USA; Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
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20
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Abstract
Two-component systems are a dominant form of bacterial signal transduction. The prototypical two-component system consists of a sensor that responds to a specific input(s) by modifying the output of a cognate regulator. Because the output of a two-component system is the amount of phosphorylated regulator, feedback mechanisms may alter the amount of regulator, and/or modify the ability of a sensor or other proteins to alter the phosphorylation state of the regulator. Two-component systems may display intrinsic feedback whereby the amount of phosphorylated regulator changes under constant inducing conditions and without the participation of additional proteins. Feedback control allows a two-component system to achieve particular steady-state levels, to reach a given steady state with distinct dynamics, to express coregulated genes in a given order, and to activate a regulator to different extents, depending on the signal acting on the sensor.
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Affiliation(s)
- Eduardo A Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut 06536; .,Yale Microbial Sciences Institute, West Haven, Connecticut 06516
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21
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Renoz F, Champagne A, Degand H, Faber AM, Morsomme P, Foray V, Hance T. Toward a better understanding of the mechanisms of symbiosis: a comprehensive proteome map of a nascent insect symbiont. PeerJ 2017; 5:e3291. [PMID: 28503376 PMCID: PMC5426354 DOI: 10.7717/peerj.3291] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 04/10/2017] [Indexed: 12/18/2022] Open
Abstract
Symbiotic bacteria are common in insects and can affect various aspects of their hosts’ biology. Although the effects of insect symbionts have been clarified for various insect symbiosis models, due to the difficulty of cultivating them in vitro, there is still limited knowledge available on the molecular features that drive symbiosis. Serratia symbiotica is one of the most common symbionts found in aphids. The recent findings of free-living strains that are considered as nascent partners of aphids provide the opportunity to examine the molecular mechanisms that a symbiont can deploy at the early stages of the symbiosis (i.e., symbiotic factors). In this work, a proteomic approach was used to establish a comprehensive proteome map of the free-living S. symbiotica strain CWBI-2.3T. Most of the 720 proteins identified are related to housekeeping or primary metabolism. Of these, 76 were identified as candidate proteins possibly promoting host colonization. Our results provide strong evidence that S. symbiotica CWBI-2.3T is well-armed for invading insect host tissues, and suggest that certain molecular features usually harbored by pathogenic bacteria are no longer present. This comprehensive proteome map provides a series of candidate genes for further studies to understand the molecular cross-talk between insects and symbiotic bacteria.
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Affiliation(s)
- François Renoz
- Biodiversity Reasearch Center, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Antoine Champagne
- Institute of Life Sciences, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Hervé Degand
- Institute of Life Sciences, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Anne-Marie Faber
- Institute of Life Sciences, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Pierre Morsomme
- Institute of Life Sciences, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Vincent Foray
- Centre de Recherche de Biochimie Macromoléculaire, Centre National de la Recherche Scientifique, Montpellier, France
| | - Thierry Hance
- Biodiversity Reasearch Center, Université catholique de Louvain, Louvain-la-Neuve, Belgium
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22
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Clayton AL, Enomoto S, Su Y, Dale C. The regulation of antimicrobial peptide resistance in the transition to insect symbiosis. Mol Microbiol 2017; 103:958-972. [PMID: 27987256 DOI: 10.1111/mmi.13598] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/05/2016] [Indexed: 01/02/2023]
Abstract
Many bacteria utilize two-component systems consisting of a sensor kinase and a transcriptional response regulator to detect environmental signals and modulate gene expression for adaptation. The response regulator PhoP and its cognate sensor kinase PhoQ compose a two-component system known for its role in responding to low levels of Mg2+ , Ca2+ , pH and to the presence of antimicrobial peptides and activating the expression of genes involved in adaptation to host association. Compared with their free-living relatives, mutualistic insect symbiotic bacteria inhabit a static environment where the requirement for sensory functions is expected to be relaxed. The insect symbiont, Sodalis glossinidius, requires PhoP to resist killing by host derived antimicrobial peptides. However, the S. glossinidius PhoQ was found to be insensitive to Mg2+ , Ca2+ and pH. Here they show that Sodalis praecaptivus, a close non host-associated relative of S. glossinidius, utilizes a magnesium sensing PhoP-PhoQ and an uncharacterized MarR-like transcriptional regulator (Sant_4061) to control antimicrobial peptide resistance in vitro. While the inactivation of phoP, phoQ or Sant_4061 completely retards the growth of S. praecaptivus in the presence of an antimicrobial peptide in vitro, inactivation of both phoP and Sant_4061 is necessary to abrogate growth of this bacterium in an insect host.
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Affiliation(s)
- Adam L Clayton
- Department of Biology, University of Utah, Salt Lake City, UT, USA
| | | | - Yinghua Su
- Department of Biology, University of Utah, Salt Lake City, UT, USA
| | - Colin Dale
- Department of Biology, University of Utah, Salt Lake City, UT, USA
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23
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Joo HS, Fu CI, Otto M. Bacterial strategies of resistance to antimicrobial peptides. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150292. [PMID: 27160595 PMCID: PMC4874390 DOI: 10.1098/rstb.2015.0292] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2016] [Indexed: 02/06/2023] Open
Abstract
Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.
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Affiliation(s)
- Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Chih-Iung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
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24
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Joo HS, Fu CI, Otto M. Bacterial strategies of resistance to antimicrobial peptides. Philos Trans R Soc Lond B Biol Sci 2016. [PMID: 27160595 DOI: 10.1098/rstb.2015.0292.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.
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Affiliation(s)
- Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Chih-Iung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
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25
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When Too Much ATP Is Bad for Protein Synthesis. J Mol Biol 2015; 427:2586-2594. [PMID: 26150063 DOI: 10.1016/j.jmb.2015.06.021] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 06/30/2015] [Accepted: 06/30/2015] [Indexed: 01/17/2023]
Abstract
Adenosine triphosphate (ATP) is the energy currency of living cells. Even though ATP powers virtually all energy-dependent activities, most cellular ATP is utilized in protein synthesis via tRNA aminoacylation and guanosine triphosphate regeneration. Magnesium (Mg(2+)), the most common divalent cation in living cells, plays crucial roles in protein synthesis by maintaining the structure of ribosomes, participating in the biochemistry of translation initiation and functioning as a counterion for ATP. A non-physiological increase in ATP levels hinders growth in cells experiencing Mg(2+) limitation because ATP is the most abundant nucleotide triphosphate in the cell, and Mg(2+) is also required for the stabilization of the cytoplasmic membrane and as a cofactor for essential enzymes. We propose that organisms cope with Mg(2+) limitation by decreasing ATP levels and ribosome production, thereby reallocating Mg(2+) to indispensable cellular processes.
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26
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Evaluating Insect-Microbiomes at the Plant-Insect Interface. J Chem Ecol 2014; 40:836-47. [DOI: 10.1007/s10886-014-0475-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 06/17/2014] [Accepted: 06/20/2014] [Indexed: 12/17/2022]
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Oakeson KF, Gil R, Clayton AL, Dunn DM, von Niederhausern AC, Hamil C, Aoyagi A, Duval B, Baca A, Silva FJ, Vallier A, Jackson DG, Latorre A, Weiss RB, Heddi A, Moya A, Dale C. Genome degeneration and adaptation in a nascent stage of symbiosis. Genome Biol Evol 2014; 6:76-93. [PMID: 24407854 PMCID: PMC3914690 DOI: 10.1093/gbe/evt210] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Symbiotic associations between animals and microbes are ubiquitous in nature, with an estimated 15% of all insect species harboring intracellular bacterial symbionts. Most bacterial symbionts share many genomic features including small genomes, nucleotide composition bias, high coding density, and a paucity of mobile DNA, consistent with long-term host association. In this study, we focus on the early stages of genome degeneration in a recently derived insect-bacterial mutualistic intracellular association. We present the complete genome sequence and annotation of Sitophilus oryzae primary endosymbiont (SOPE). We also present the finished genome sequence and annotation of strain HS, a close free-living relative of SOPE and other insect symbionts of the Sodalis-allied clade, whose gene inventory is expected to closely resemble the putative ancestor of this group. Structural, functional, and evolutionary analyses indicate that SOPE has undergone extensive adaptation toward an insect-associated lifestyle in a very short time period. The genome of SOPE is large in size when compared with many ancient bacterial symbionts; however, almost half of the protein-coding genes in SOPE are pseudogenes. There is also evidence for relaxed selection on the remaining intact protein-coding genes. Comparative analyses of the whole-genome sequence of strain HS and SOPE highlight numerous genomic rearrangements, duplications, and deletions facilitated by a recent expansion of insertions sequence elements, some of which appear to have catalyzed adaptive changes. Functional metabolic predictions suggest that SOPE has lost the ability to synthesize several essential amino acids and vitamins. Analyses of the bacterial cell envelope and genes encoding secretion systems suggest that these structures and elements have become simplified in the transition to a mutualistic association.
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Affiliation(s)
- Kelly F. Oakeson
- Department of Biology, University of Utah
- *Corresponding author: E-mail:
| | - Rosario Gil
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
| | | | | | | | - Cindy Hamil
- Department of Human Genetics, University of Utah
| | - Alex Aoyagi
- Department of Human Genetics, University of Utah
| | - Brett Duval
- Department of Human Genetics, University of Utah
| | | | - Francisco J. Silva
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
| | - Agnès Vallier
- INSA-Lyon, INRA, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, Villeurbanne, France
| | | | - Amparo Latorre
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Área de Genómica y Salud, Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunitat Valenciana FISABIO – Salud Pública, Valencia, Spain
| | | | - Abdelaziz Heddi
- INSA-Lyon, INRA, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, Villeurbanne, France
| | - Andrés Moya
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Área de Genómica y Salud, Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunitat Valenciana FISABIO – Salud Pública, Valencia, Spain
| | - Colin Dale
- Department of Biology, University of Utah
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Novel Rickettsiella bacterium in the leafhopper Orosius albicinctus (Hemiptera: Cicadellidae). Appl Environ Microbiol 2013; 79:4246-52. [PMID: 23645190 DOI: 10.1128/aem.00721-13] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Bacteria in the genus Rickettsiella (Coxiellaceae), which are mainly known as arthropod pathogens, are emerging as excellent models to study transitions between mutualism and pathogenicity. The current report characterizes a novel Rickettsiella found in the leafhopper Orosius albicinctus (Hemiptera: Cicadellidae), a major vector of phytoplasma diseases in Europe and Asia. Denaturing gradient gel electrophoresis (DGGE) and pyrosequencing were used to survey the main symbionts of O. albicinctus, revealing the obligate symbionts Sulcia and Nasuia, and the facultative symbionts Arsenophonus and Wolbachia, in addition to Rickettsiella. The leafhopper Rickettsiella is allied with bacteria found in ticks. Screening O. albicinctus from the field showed that Rickettsiella is highly prevalent, with over 60% of individuals infected. A stable Rickettsiella infection was maintained in a leafhopper laboratory colony for at least 10 generations, and fluorescence microscopy localized bacteria to accessory glands of the female reproductive tract, suggesting that the bacterium is vertically transmitted. Future studies will be needed to examine how Rickettsiella affects host fitess and its ability to vector phytopathogens.
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Induction of the Yersinia pestis PhoP-PhoQ regulatory system in the flea and its role in producing a transmissible infection. J Bacteriol 2013; 195:1920-30. [PMID: 23435973 DOI: 10.1128/jb.02000-12] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transmission of Yersinia pestis is greatly enhanced after it forms a bacterial biofilm in the foregut of the flea vector that interferes with normal blood feeding. Here we report that the ability to produce a normal foregut-blocking infection depends on induction of the Y. pestis PhoP-PhoQ two-component regulatory system in the flea. Y. pestis phoP-negative mutants achieved normal infection rates and bacterial loads in the flea midgut but produced a less cohesive biofilm both in vitro and in the flea and had a greatly reduced ability to localize to and block the flea foregut. Thus, not only is the PhoP-PhoQ system induced in the flea gut environment, but also this induction is required to produce a normal transmissible infection. The altered biofilm phenotype in the flea was not due to lack of PhoPQ-dependent or PmrAB-dependent addition of aminoarabinose to the Y. pestis lipid A, because an aminoarabinose-deficient mutant that is highly sensitive to cationic antimicrobial peptides had a normal phenotype in the flea digestive tract. In addition to enhancing transmissibility, induction of the PhoP-PhoQ system in the arthropod vector prior to transmission may preadapt Y. pestis to resist the initial encounter with the mammalian innate immune response.
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Login FH, Heddi A. Insect immune system maintains long-term resident bacteria through a local response. JOURNAL OF INSECT PHYSIOLOGY 2013; 59:232-239. [PMID: 22771302 DOI: 10.1016/j.jinsphys.2012.06.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 06/23/2012] [Accepted: 06/27/2012] [Indexed: 05/27/2023]
Abstract
Long-term associations between bacteria and animals are widely represented in nature and play an important role in animal adaptation and evolution. In insects thriving on nutritionally unbalanced diets, intracellular symbiotic bacteria (endosymbionts) complement the host nutrients with amino acids and vitamins and interfere with host physiology and reproduction. Endosymbionts permanently infect host cells, called bacteriocytes, which express an adapted local immune response that permits symbiont maintenance and control. Among the immune players in bacteriocytes, the coleoptericin A (ColA) antimicrobial peptide of the cereal weevil, Sitophilus zeamais, was recently found to specifically trigger endosymbionts and to inhibit their cytokinesis, thereby limiting bacterial cell division and dispersion throughout the insect tissues. This review focuses on the biological and evolutionary features of Sitophilus symbiosis, and discusses the possible interactions of ColA with weevil endosymbiont proteins and pathways.
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Affiliation(s)
- Frédéric H Login
- INSA-Lyon, UMR203 BF2I, INRA, Biologie Fonctionnelle Insectes et Interactions, Bat. Louis-Pasteur 20 ave. Albert Einstein, F-69621 Villeurbanne, France
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31
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Transcriptome of Dickeya dadantii infecting Acyrthosiphon pisum reveals a strong defense against antimicrobial peptides. PLoS One 2013; 8:e54118. [PMID: 23342088 PMCID: PMC3544676 DOI: 10.1371/journal.pone.0054118] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 12/05/2012] [Indexed: 01/01/2023] Open
Abstract
The plant pathogenic bacterium Dickeya dadantii has recently been shown to be able to kill the aphid Acyrthosiphon pisum. While the factors required to cause plant disease are now well characterized, those required for insect pathogeny remain mostly unknown. To identify these factors, we analyzed the transcriptome of the bacteria isolated from infected aphids. More than 150 genes were upregulated and 300 downregulated more than 5-fold at 3 days post infection. No homologue to known toxin genes could be identified in the upregulated genes. The upregulated genes reflect the response of the bacteria to the conditions encountered inside aphids. While only a few genes involved in the response to oxidative stress were induced, a strong defense against antimicrobial peptides (AMP) was induced. Expression of a great number of efflux proteins and transporters was increased. Besides the genes involved in LPS modification by addition of 4-aminoarabinose (the arnBCADTEF operon) and phosphoethanolamine (pmrC, eptB) usually induced in Gram negative bacteria in response to AMPs, dltBAC and pbpG genes, which confer Gram positive bacteria resistance to AMPs by adding alanine to teichoic acids, were also induced. Both types of modification confer D. dadantii resistance to the AMP polymyxin. A. pisum harbors symbiotic bacteria and it is thought that it has a very limited immune system to maintain these populations and do not synthesize AMPs. The arnB mutant was less pathogenic to A. pisum, which suggests that, in contrast to what has been supposed, aphids do synthesize AMP.
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Clayton AL, Oakeson KF, Gutin M, Pontes A, Dunn DM, von Niederhausern AC, Weiss RB, Fisher M, Dale C. A novel human-infection-derived bacterium provides insights into the evolutionary origins of mutualistic insect-bacterial symbioses. PLoS Genet 2012; 8:e1002990. [PMID: 23166503 PMCID: PMC3499248 DOI: 10.1371/journal.pgen.1002990] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 08/10/2012] [Indexed: 01/22/2023] Open
Abstract
Despite extensive study, little is known about the origins of the mutualistic bacterial endosymbionts that inhabit approximately 10% of the world's insects. In this study, we characterized a novel opportunistic human pathogen, designated “strain HS,” and found that it is a close relative of the insect endosymbiont Sodalis glossinidius. Our results indicate that ancestral relatives of strain HS have served as progenitors for the independent descent of Sodalis-allied endosymbionts found in several insect hosts. Comparative analyses indicate that the gene inventories of the insect endosymbionts were independently derived from a common ancestral template through a combination of irreversible degenerative changes. Our results provide compelling support for the notion that mutualists evolve from pathogenic progenitors. They also elucidate the role of degenerative evolutionary processes in shaping the gene inventories of symbiotic bacteria at a very early stage in these mutualistic associations. Many insects harbor symbiotic bacteria that perform diverse functions within their hosts. However, the origins of these associations have been difficult to define. In this study we isolate a novel bacterium from a human infection and show that this bacterium is a close relative of the Sodalis-allied clade of insect symbionts. Comparative genomic analyses reveal that this organism maintains many genes that have been inactivated and lost independently in derived insect symbionts as a result of rapid genome degeneration. Our work also shows that recently derived Sodalis-allied symbionts maintain a significant population of “cryptic” pseudogenes that are assumed to have no beneficial function in the symbiosis but have not yet accumulated mutations that disrupt their translation. Taken together, our results show that genome degeneration proceeds rapidly following the onset of symbiosis. They also highlight the potential for diverse insect taxa to acquire closely related insect symbionts as a consequence of vectoring bacterial pathogens to plants and animals.
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Affiliation(s)
- Adam L Clayton
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America.
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Caljon G, De Vooght L, Van Den Abbeele J. Options for the delivery of anti-pathogen molecules in arthropod vectors. J Invertebr Pathol 2012; 112 Suppl:S75-82. [PMID: 22841635 DOI: 10.1016/j.jip.2012.07.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 05/15/2012] [Accepted: 05/18/2012] [Indexed: 10/28/2022]
Abstract
Blood feeding arthropods are responsible for the transmission of a large array of medically important infectious agents that include viruses, bacteria, protozoan parasites and helminths. The recent development of transgenic and paratransgenic technologies have enabled supplementing the immune system of these arthropod vectors with anti-pathogen effector molecules in view of compromising their vector competence for these microbial agents. The characteristics of the selected anti-pathogen compound will largely determine the efficacy and specificity of this approach. Low specificity will generally result in bystander effects, likely having a direct or indirect fitness cost for the arthropod. In contrast, the use of highly specific compounds from the adaptive immune system of vertebrates such as antibody derived fragments is more likely to enable highly specific effects without conferring a selective disadvantage to the (para)transgenic arthropods. Here, Nanobodies® are excellent candidates to increase the immune competence of arthropods. Moreover they were shown to exert a novel type of anti-pathogen activity that uniquely depends on their small size.
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Affiliation(s)
- Guy Caljon
- Department of Biomedical Sciences, Unit of Veterinary Protozoology, Institute of Tropical Medicine Antwerp (ITM), Antwerp, Belgium.
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Chrudimský T, Husník F, Nováková E, Hypša V. Candidatus Sodalis melophagi sp. nov.: phylogenetically independent comparative model to the tsetse fly symbiont Sodalis glossinidius. PLoS One 2012; 7:e40354. [PMID: 22815743 PMCID: PMC3398932 DOI: 10.1371/journal.pone.0040354] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Accepted: 06/07/2012] [Indexed: 12/21/2022] Open
Abstract
Bacteria of the genus Sodalis live in symbiosis with various groups of insects. The best known member of this group, a secondary symbiont of tsetse flies Sodalis glossinidius, has become one of the most important models in investigating establishment and evolution of insect-bacteria symbiosis. It represents a bacterium in the early/intermediate state of the transition towards symbiosis, which allows for exploring such interesting topics as: usage of secretory systems for entering the host cell, tempo of the genome modification, and metabolic interaction with a coexisting primary symbiont. In this study, we describe a new Sodalis species which could provide a useful comparative model to the tsetse symbiont. It lives in association with Melophagus ovinus, an insect related to tsetse flies, and resembles S. glossinidius in several important traits. Similar to S. glossinidius, it cohabits the host with another symbiotic bacterium, the bacteriome-harbored primary symbiont of the genus Arsenophonus. As a typical secondary symbiont, Candidatus Sodalis melophagi infects various host tissues, including bacteriome. We provide basic morphological and molecular characteristics of the symbiont and show that these traits also correspond to the early/intermediate state of the evolution towards symbiosis. Particularly, we demonstrate the ability of the bacterium to live in insect cell culture as well as in cell-free medium. We also provide basic characteristics of type three secretion system and using three reference sequences (16 S rDNA, groEL and spaPQR region) we show that the bacterium branched within the genus Sodalis, but originated independently of the two previously described symbionts of hippoboscoids. We propose the name Candidatus Sodalis melophagi for this new bacterium.
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Affiliation(s)
- Tomáš Chrudimský
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.
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Balmand S, Lohs C, Aksoy S, Heddi A. Tissue distribution and transmission routes for the tsetse fly endosymbionts. J Invertebr Pathol 2012; 112 Suppl:S116-22. [PMID: 22537833 DOI: 10.1016/j.jip.2012.04.002] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 04/02/2012] [Accepted: 04/04/2012] [Indexed: 10/28/2022]
Abstract
The tsetse fly Glossina is the vector of the protozoan Trypanosoma brucei spp., which causes Human and Animal African Trypanosomiasis in sub-Saharan African countries. To supplement their unbalanced vertebrate bloodmeal diet, flies permanently harbor the obligate bacterium Wigglesworthia glossinidia, which resides in bacteriocytes in the midgut bacteriome organ as well as in milk gland organ. Tsetse flies also harbor the secondary facultative endosymbionts (S-symbiont) Sodalis glossinidius that infects various tissues and Wolbachia that infects germ cells. Tsetse flies display viviparous reproductive biology where a single embryo hatches and completes its entire larval development in utero and receives nourishments in the form of milk secreted by mother's accessory glands (milk glands). To analyze the precise tissue distribution of the three endosymbiotic bacteria and to infer the way by which each symbiotic partner is transmitted from parent to progeny, we conducted a Fluorescence In situ Hybridization (FISH) study to survey bacterial spatial distribution across the fly tissues. We show that bacteriocytes are mono-infected with Wigglesworthia, while both Wigglesworthia and Sodalis are present in the milk gland lumen. Sodalis was further seen in the uterus, spermathecae, fat body, milk and intracellular in the milk gland cells. Contrary to Wigglesworthia and Sodalis, Wolbachia were the only bacteria infecting oocytes, trophocytes, and embryos at early embryonic stages. Furthermore, Wolbachia were not seen in the milk gland and in the fat body. This work further highlights the diversity of symbiont interactions in multipartner associations and supports two maternal routes of symbiont inheritance in the tsetse fly: Wolbachia through oocytes, and, Wigglesworthia and Sodalis by means of milk gland bacterial infection at early post-embryonic stages.
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Affiliation(s)
- Séverine Balmand
- INSA-Lyon, INRA, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, F-69621 Villeurbanne, France.
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Symbiosis: Sheltered bacteria lose their senses. Nat Rev Microbiol 2011; 10:4. [PMID: 22173556 DOI: 10.1038/nrmicro2718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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