1
|
Brivio MF, Mastore M. When Appearance Misleads: The Role of the Entomopathogen Surface in the Relationship with Its Host. INSECTS 2020; 11:E387. [PMID: 32585858 PMCID: PMC7348879 DOI: 10.3390/insects11060387] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 06/18/2020] [Accepted: 06/20/2020] [Indexed: 12/14/2022]
Abstract
Currently, potentially harmful insects are controlled mainly by chemical synthetic insecticides, but environmental emergencies strongly require less invasive control techniques. The use of biological insecticides in the form of entomopathogenic organisms is undoubtedly a fundamental resource for the biological control of insect pests in the future. These infectious agents and endogenous parasites generally act by profoundly altering the host's physiology to death, but their success is closely related to the neutralization of the target insect's immune response. In general, entomopathogen parasites, entomopathogenic bacteria, and fungi can counteract immune processes through the effects of secretion/excretion products that interfere with and damage the cells and molecules typical of innate immunity. However, these effects are observed in the later stages of infection, whereas the risk of being recognized and neutralized occurs very early after penetration and involves the pathogen surface components and molecular architecture; therefore, their role becomes crucial, particularly in the earliest pathogenesis. In this review, we analyze the evasion/interference strategies that entomopathogens such as the bacterium Bacillus thuringiensis, fungi, nematocomplexes, and wasps implement in the initial stages of infection, i.e., the phases during which body or cell surfaces play a key role in the interaction with the host receptors responsible for the immunological discrimination between self and non-self. In this regard, these organisms demonstrate evasive abilities ascribed to their body surface and cell wall; it appears that the key process of these mechanisms is the capability to modify the surface, converting it into an immunocompatible structure, or interaction that is more or less specific to host factors.
Collapse
Affiliation(s)
- Maurizio Francesco Brivio
- Laboratory of Comparative Immunology and Parasitology, Department of Theoretical and Applied Sciences, University of Insubria, 21100 Varese, Italy;
| | | |
Collapse
|
2
|
Kenney E, Hawdon JM, O'Halloran D, Eleftherianos I. Heterorhabditis bacteriophora Excreted-Secreted Products Enable Infection by Photorhabdus luminescens Through Suppression of the Imd Pathway. Front Immunol 2019; 10:2372. [PMID: 31636642 PMCID: PMC6787769 DOI: 10.3389/fimmu.2019.02372] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 09/20/2019] [Indexed: 12/14/2022] Open
Abstract
Upon entering the hemocoel of its insect host, the entomopathogenic nematode Heterorhabditis bacteriophora releases its symbiotic bacteria Photorhabdus luminescens, which is also a strong insect pathogen. P. luminescens is known to suppress the insect immune response independently following its release, but the nematode appears to enact its own immunosuppressive mechanisms during the earliest phases of an infection. H. bacteriophora was found to produce a unique set of excreted-secreted proteins in response to host hemolymph, and while basal secretions are immunogenic with regard to Diptericin expression through the Imd pathway, host-induced secretions suppress this expression to a level below that of controls in Drosophila melanogaster. This effect is consistent in adults, larvae, and isolated larval fat bodies, and the magnitude of suppression is dose-dependent. By reducing the expression of Diptericin, an antimicrobial peptide active against Gram-negative bacteria, the activated excreted-secreted products enable a more rapid propagation of P. luminescens that corresponds to more rapid host mortality. The identification and isolation of the specific proteins responsible for this suppression represents an exciting field of study with potential for enhancing the biocontrol of insect pests and treatment of diseases associated with excessive inflammation.
Collapse
Affiliation(s)
- Eric Kenney
- Infection and Innate Immunity Lab, Department of Biological Sciences, George Washington University, Washington, DC, United States
| | - John M Hawdon
- Department of Microbiology, Immunology, and Tropical Medicine, George Washington University, Washington, DC, United States
| | - Damien O'Halloran
- Infection and Innate Immunity Lab, Department of Biological Sciences, George Washington University, Washington, DC, United States.,Institute for Neuroscience, Department of Biological Sciences, George Washington University, Washington, DC, United States
| | - Ioannis Eleftherianos
- Infection and Innate Immunity Lab, Department of Biological Sciences, George Washington University, Washington, DC, United States
| |
Collapse
|
3
|
Mastore M, Quadroni S, Toscano A, Mottadelli N, Brivio MF. Susceptibility to entomopathogens and modulation of basal immunity in two insect models at different temperatures. J Therm Biol 2018; 79:15-23. [PMID: 30612676 DOI: 10.1016/j.jtherbio.2018.11.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 10/31/2018] [Accepted: 11/12/2018] [Indexed: 11/30/2022]
Abstract
In this work, we analysed the efficacy of different commercial bio-insecticides (Steinernema feltiae, Steinernema carpocapsae, Heterorhabditis bacteriophora and Bacillus thuringiensis) by valuating the mortality induced on two insect models, Galleria mellonella (Lepidoptera) and Sarcophaga africa (Diptera) after exposure to different temperatures (10, 20 and 30 °C). Moreover, we investigated the effects of temperature on the basal humoral immunity of the two target insects; particularly, phenoloxidase (PO) and lysozyme activity. Our results show that G. mellonella is susceptible to all bio-insecticides at all the examined temperatures, except when infected at 10 °C with S. carpocapsae and at 30 °C with S. feltiae and B. thuringiensis. S. africa is more susceptible at 30 °C to all bioinsecticides; whereas, when infected at 10 and 20 °C, H. bacteriophora is the most efficient. Temperature modulates PO activity of both G. mellonella and S. africa, otherwise variations in lysozyme activity is observed only in G. mellonella. Except for a possible correlation between the increased lysozyme activity and the delayed Bt efficacy recorded on G. mellonella at 30 °C, a different resistance to bio-insecticides at different temperatures does not seem to be associated to variations of the host basal immunity, probably due to immunoevasive and immunodepressive strategies of these entomopathogens.
Collapse
Affiliation(s)
- Maristella Mastore
- Lab. of Comparative Immunology and Parasitology, Dept. of Theoretical and Applied Sciences, University of Insubria, Varese, Italy
| | - Silvia Quadroni
- Lab. of Ecology, Dept. of Science and High Technology, University of Insubria, Varese, Italy
| | - Andrea Toscano
- Lab. of Comparative Immunology and Parasitology, Dept. of Theoretical and Applied Sciences, University of Insubria, Varese, Italy
| | - Nicolò Mottadelli
- Lab. of Comparative Immunology and Parasitology, Dept. of Theoretical and Applied Sciences, University of Insubria, Varese, Italy
| | - Maurizio F Brivio
- Lab. of Comparative Immunology and Parasitology, Dept. of Theoretical and Applied Sciences, University of Insubria, Varese, Italy.
| |
Collapse
|
4
|
Kumar A, Sýkorová P, Demo G, Dobeš P, Hyršl P, Wimmerová M. A Novel Fucose-binding Lectin from Photorhabdus luminescens (PLL) with an Unusual Heptabladed β-Propeller Tetrameric Structure. J Biol Chem 2016; 291:25032-25049. [PMID: 27758853 DOI: 10.1074/jbc.m115.693473] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Revised: 09/18/2016] [Indexed: 01/08/2023] Open
Abstract
Photorhabdus luminescens is known for its symbiosis with the entomopathogenic nematode Heterorhabditis bacteriophora and its pathogenicity toward insect larvae. A hypothetical protein from P. luminescens was identified, purified from the native source, and characterized as an l-fucose-binding lectin, named P. luminescens lectin (PLL). Glycan array and biochemical characterization data revealed PLL to be specific toward l-fucose and the disaccharide glycan 3,6-O-Me2-Glcβ1-4(2,3-O-Me2)Rhaα-O-(p-C6H4)-OCH2CH2NH2 PLL was discovered to be a homotetramer with an intersubunit disulfide bridge. The crystal structures of native and recombinant PLL revealed a seven-bladed β-propeller fold creating seven putative fucose-binding sites per monomer. The crystal structure of the recombinant PLL·l-fucose complex confirmed that at least three sites were fucose-binding. Moreover, the crystal structures indicated that some of the other sites are masked either by the tetrameric nature of the lectin or by incorporation of the C terminus of the lectin into one of these sites. PLL exhibited an ability to bind to insect hemocytes and the cuticular surface of a nematode, H. bacteriophora.
Collapse
Affiliation(s)
- Atul Kumar
- From the Central European Institute of Technology (CEITEC)
| | - Petra Sýkorová
- From the Central European Institute of Technology (CEITEC).,the Department of Biochemistry, Faculty of Science
| | - Gabriel Demo
- From the Central European Institute of Technology (CEITEC).,the National Centre for Biomolecular Research, Faculty of Science, and
| | - Pavel Dobeš
- the Department of Animal Physiology and Immunology, Institute of Experimental Biology, Masaryk University, Brno 625 00, Czech Republic
| | - Pavel Hyršl
- the Department of Animal Physiology and Immunology, Institute of Experimental Biology, Masaryk University, Brno 625 00, Czech Republic
| | - Michaela Wimmerová
- From the Central European Institute of Technology (CEITEC), .,the Department of Biochemistry, Faculty of Science.,the National Centre for Biomolecular Research, Faculty of Science, and
| |
Collapse
|
5
|
Application and commercialization of nematodes. Appl Microbiol Biotechnol 2013; 97:6181-8. [DOI: 10.1007/s00253-013-4941-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Revised: 04/18/2013] [Accepted: 04/19/2013] [Indexed: 11/26/2022]
|
6
|
Li X, Cowles EA, Cowles RS, Gaugler R, Cox-Foster DL. Characterization of immunosuppressive surface coat proteins from Steinernema glaseri that selectively kill blood cells in susceptible hosts. Mol Biochem Parasitol 2009; 165:162-9. [PMID: 19428663 DOI: 10.1016/j.molbiopara.2009.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Revised: 01/05/2009] [Accepted: 02/01/2009] [Indexed: 11/30/2022]
Abstract
Surface coat proteins (SCPs) of entomopathogenic nematodes are implicated in the suppression/evasion of host immune responses, which is required for successful host colonization. Steinernema glaseri NC strain SCPs suppressed immune responses in oriental beetle larvae (Exomala orientalis), a susceptible host for S. glaseri, in a dosage-dependent manner, thus protecting Heterorhabditis bacteriophora from being killed in the same host. Melanization of H. bacteriophora decreased from 92+/-5% in the untreated check to 1+/-3% when protected by injection of 230ng of S. glaseri SCPs. As the SCPs dosage increased, freely moving H. bacteriophora increased from 3+/-4% in the untreated group to 57+/-15% with an SCPs dose of 940ng. At 2h and in the absence of SCPs, 8% and 11% of hemocytes of E. orientalis were stained by propidium iodide and Hoechst, respectively. When exposed to 300ng/microl SCPs, 70% and 96% were stained, respectively. At 6h, propidium iodide stained 37% and 92% of the hemocytes without and with SCPs, respectively. In contrast, more than 90% of the cells were stained by Hoechst with or without SCPs. As native proteins, two isolated S. glaseri SCPs had an immunosuppressive effect; they were each composed of 38kDa (PI=4.6) and 56kDa (PI=3.6) subunits. SCP peptides were sequenced using LC-MS/MS and the mass fingerprints obtained with MALDI-TOF-MS; there were no significant matches found in peptide databases, which suggests that the SCPs studied are novel proteins. Twelve cDNA sequences were derived based on short peptides and 7 of them had no significant match against the Caenorhabditis elegans protein database. One of the cDNA matched an unknown C. elegans protein and the remaining 4 cDNAs matched proteins of C. elegans and Brugia malayi.
Collapse
Affiliation(s)
- Xinyi Li
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA
| | | | | | | | | |
Collapse
|
7
|
Li XY, Cowles RS, Cowles EA, Gaugler R, Cox-Foster DL. Relationship between the successful infection by entomopathogenic nematodes and the host immune response. Int J Parasitol 2007; 37:365-74. [PMID: 17275827 DOI: 10.1016/j.ijpara.2006.08.009] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Revised: 08/24/2006] [Accepted: 08/25/2006] [Indexed: 11/28/2022]
Abstract
Reproduction of entomopathogenic nematodes requires that they escape recognition by a host's immune system or that they have mechanisms to escape encapsulation and melanization. We investigated the immune responses of larvae for the greater wax moth (Galleria mellonella), tobacco hornworm (Manduca sexta), Japanese beetle (Popillia japonica), northern masked chafer (Cyclocephala borealis), oriental beetle (Exomala orientalis) and adult house crickets (Acheta domesticus), challenged with infective juveniles from different species and strains of entomopathogenic nematodes. The in vivo immune responses of hosts were correlated with nematode specificity and survival found by infection assays. In P. japonica, 45% of injected infective juveniles from Steinernema glaseri NC strain survived; whereas the hemocytes from the beetle strongly encapsulated and melanized the Heterorhabditis bacteriophora HP88 strain, S. glaseri FL strain, Steinernema scarabaei and Steinernema feltiae. Overall, H. bacteriophora was intensively melanized in resistant insect species (E. orientalis, P. japonica and C. borealis) and had the least ability to escape the host immune response. Steinernema glaseri NC strain suppressed the immune responses in susceptible hosts (M. sexta, E. orientalis and P. japonica), whereas S. glaseri FL strain was less successful. Using an in vitro assay, we found that hemocytes from G. mellonella, P. japonica, M. sexta and A. domestica recognized both nematode species quickly. However, many S. glaseri in M. sexta and H. bacteriophora in G. mellonella escaped from hemocyte encapsulation by 24h. These data indicate that, while host recognition underlies some of the differences between resistant and susceptible host species, escape from encapsulation following recognition can also allow successful infection. Co-injected surface-coat proteins from S. glaseri did not protect H. bacteriophora in M. sexta but did protect H. bacteriophora in E. orientalis larva; therefore, surface coat proteins do not universally convey host susceptibility. Comparisons of surface coat proteins by native and SDS-PAGE demonstrated different protein compositions between H. bacteriophora and S. glaseri and between the two strains of S. glaseri.
Collapse
Affiliation(s)
- X-Y Li
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA
| | | | | | | | | |
Collapse
|
8
|
Enright MR, Griffin CT. Effects of Paenibacillus nematophilus on the entomopathogenic nematode Heterorhabditis megidis. J Invertebr Pathol 2005; 88:40-8. [PMID: 15707868 DOI: 10.1016/j.jip.2004.10.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2004] [Revised: 09/29/2004] [Accepted: 10/08/2004] [Indexed: 11/29/2022]
Abstract
The insect parasitic nematodes Heterorhabditis spp. are mutualistically associated with entomopathogenic bacteria, Photorhabdus spp. A novel association has been detected between H. megidis isolate EU17 and the endospore-forming bacterium Paenibacillus nematophilus. P. nematophilus sporangia adhere to infective juveniles (IJs) of H. megidis and develop in insect hosts along with the nematodes and their symbiont. We tested the effects of P. nematophilus on H. megidis. The yield and quality (size, energy reserves, and storage survival) of IJs were not affected by co-culture in insects with P. nematophilus. Dispersal of IJs in sand and on agar was inhibited by adhering P. nematophilus sporangia: fewer than 2% of IJs with P. nematophilus sporangia reached the bottom of a sand column, compared to 30% of the control treatment. Sporangia significantly reduced infectivity of H. megidis for wax moth larvae in sand, but not in a close contact (filter paper) assay. The results suggest that P. nematophilus may reduce the transmission potential of H. megidis through impeding the motility of IJs.
Collapse
Affiliation(s)
- Michael R Enright
- Department of Biology and Institute of Bioengineering and Agroecology, National University of Ireland, Maynooth, Co. Kildare, Ireland
| | | |
Collapse
|