1
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Brahma S, Chatterjee S, Dey A. Role of eicosanoids in insect immunity: new insights and recent advances. INSECT SCIENCE 2024. [PMID: 39158024 DOI: 10.1111/1744-7917.13434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 06/30/2024] [Accepted: 07/12/2024] [Indexed: 08/20/2024]
Abstract
Viruses, bacteria, fungus, protozoans, and different metazoan parasites and parasitoids present a constant threat to insects. Insect immunity has two components: humoral and cell mediated. Humoral immunity can be achieved by various antimicrobial proteins, namely, cecropins, sarcotoxin, defensin, attacin, etc. The cell-mediated immunity comprises various cells having immune functions fostering nodulation, phagocytosis, microaggregation, encapsulation etc. Eicosanoids play a crucial role in insect immunity comparable to other animals. The above-mentioned are signaling molecules derived from polyunsaturated fatty acids and they exert numerous physiological effects, namely, inflammation, immune modulation, and regulation of cellular processes. The review article elucidates various roles of eicosanoids, namely, nodulation reaction, Toll signaling pathway, nitric oxide (NO) generation, Ca2+ mobilization, production of reactive oxygen species (ROS), actin polymerization and aquaporin activation. Eicosanoids can function in immune priming in insects drawing hemocytes. An agent named Duox was also identified serving as ROS generator in insect gut. Moreover, role of Repat gene in insect immunity was also studied. However, recently the role of prostacyclin (PGI2) was found to be negative as it inhibits platelet aggregation. In this brief review, we have tried to shed light on the various functions of eicosanoids in immunity of insect those have been discovered recently. This concise study will allow to decipher eicosanoids' function in insect immunity in a nutshell, and it will pave the way for more researches to understand the key players of insect immunity which may eventually help to develop novel vector and pest control strategies in near future.
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Affiliation(s)
- Shubhranil Brahma
- Department of Zoology, Iswar Chandra Vidyasagar College, Belonia, South Tripura, Tripura, India
| | - Somnath Chatterjee
- Department of Zoology, Dr. Bhupendra Nath Dutta Smriti Mahavidyalaya, Hatgobindapur, Purba Bardhaman, West Bengal, India
| | - Atrayee Dey
- Post Graduate Department of Zoology, Banwarilal Bhalotia College, Asansol, Paschim Bardhaman, West Bengal, India
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2
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Zhang W, Chen X, Eleftherianos I, Mohamed A, Bastin A, Keyhani NO. Cross-talk between immunity and behavior: insights from entomopathogenic fungi and their insect hosts. FEMS Microbiol Rev 2024; 48:fuae003. [PMID: 38341280 PMCID: PMC10883697 DOI: 10.1093/femsre/fuae003] [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: 06/23/2023] [Revised: 02/05/2024] [Accepted: 02/09/2024] [Indexed: 02/12/2024] Open
Abstract
Insects are one of the most successful animals in nature, and entomopathogenic fungi play a significant role in the natural epizootic control of insect populations in many ecosystems. The interaction between insects and entomopathogenic fungi has continuously coevolved over hundreds of millions of years. Many components of the insect innate immune responses against fungal infection are conserved across phyla. Additionally, behavioral responses, which include avoidance, grooming, and/or modulation of body temperature, have been recognized as important mechanisms for opposing fungal pathogens. In an effort to investigate possible cross-talk and mediating mechanisms between these fundamental biological processes, recent studies have integrated and/or explored immune and behavioral responses. Current information indicates that during discrete stages of fungal infection, several insect behavioral and immune responses are altered simultaneously, suggesting important connections between the two systems. This review synthesizes recent advances in our understanding of the physiological and molecular aspects influencing cross-talk between behavioral and innate immune antifungal reactions, including chemical perception and olfactory pathways.
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Affiliation(s)
- Wei Zhang
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering (Ministry of Education), Guizhou University, Guiyang, Huaxi District 550025, China
| | - Xuanyu Chen
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering (Ministry of Education), Guizhou University, Guiyang, Huaxi District 550025, China
| | - Ioannis Eleftherianos
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, United States
| | - Amr Mohamed
- Department of Entomology, Faculty of Science, Cairo University, Giza 12613, Egypt
- Research fellow, King Saud University Museum of Arthropods, Plant Protection Department, College of Food and Agricultural Sciences, King Saud University, Saudi Arabia
| | - Ashley Bastin
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, United States
| | - Nemat O Keyhani
- Department of Biological Sciences, University of Illinois, Chicago, IL 60607, United States
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3
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Wrońska AK, Kaczmarek A, Boguś MI, Kuna A. Lipids as a key element of insect defense systems. Front Genet 2023; 14:1183659. [PMID: 37359377 PMCID: PMC10289264 DOI: 10.3389/fgene.2023.1183659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 05/31/2023] [Indexed: 06/28/2023] Open
Abstract
The relationship between insect pathogenic fungi and their insect hosts is a classic example of a co-evolutionary arms race between pathogen and target host: parasites evolve towards mechanisms that increase their advantage over the host, and the host increasingly strengthens its defenses. The present review summarizes the literature data describing the direct and indirect role of lipids as an important defense mechanism during fungal infection. Insect defense mechanisms comprise anatomical and physiological barriers, and cellular and humoral response mechanisms. The entomopathogenic fungi have the unique ability to digest the insect cuticle by producing hydrolytic enzymes with chitin-, lipo- and proteolytic activity; besides the oral tract, cuticle pays the way for fungal entry within the host. The key factor in insect resistance to fungal infection is the presence of certain types of lipids (free fatty acids, waxes or hydrocarbons) which can promote or inhibit fungal attachment to cuticle, and might also have antifungal activity. Lipids are considered as an important source of energy, and as triglycerides are stored in the fat body, a structure analogous to the liver and adipose tissue in vertebrates. In addition, the fat body plays a key role in innate humoral immunity by producing a range of bactericidal proteins and polypeptides, one of which is lysozyme. Energy derived from lipid metabolism is used by hemocytes to migrate to the site of fungal infection, and for phagocytosis, nodulation and encapsulation. One polyunsaturated fatty acid, arachidonic acid, is used in the synthesis of eicosanoids, which play several crucial roles in insect physiology and immunology. Apolipoprotein III is important compound with antifungal activity, which can modulate insect cellular response and is considered as important signal molecule.
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Affiliation(s)
- Anna Katarzyna Wrońska
- Museum and Institute of Zoology, Polish Academy of Science, Warszawa, Poland
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences, Warsaw, Poland
| | - Agata Kaczmarek
- Museum and Institute of Zoology, Polish Academy of Science, Warszawa, Poland
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences, Warsaw, Poland
| | - Mieczysława Irena Boguś
- Museum and Institute of Zoology, Polish Academy of Science, Warszawa, Poland
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences, Warsaw, Poland
| | - Anna Kuna
- Independent Researcher, Warsaw, Poland
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4
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Li S, Liu F, Kang Z, Li X, Lu Y, Li Q, Pang Y, Zheng F, Yin X. Cellular immune responses of the yellow peach moth, Conogethes punctiferalis (Lepidoptera: Crambidae), to the entomopathogenic fungus, Beauveria bassiana (Hypocreales: Cordycipitaceae). J Invertebr Pathol 2022; 194:107826. [PMID: 36075444 DOI: 10.1016/j.jip.2022.107826] [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: 10/12/2021] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 11/27/2022]
Abstract
The yellow peach moth (YPM), Conogethes punctiferalis, is a destructive insect pest of maize in eastern China and adapts to diverse environments, especially against pathogens. In insects, innate immunity comprising both humoral and cellular defense responses, is the primary defense against invading microbial pathogens. In this study, we identified five types of circulating hemocytes from the hemolymph of YPM larvae and analyzed their alterations and functions in immune responses to the infection of Beauveria bassiana, an entomopathogenic fungus infesting many lepidopteran species. The identified hemocytes included prohemocytes, plasmatocytes, granulocytes, spherulocytes and oenocytoids. Significant decreases of total and differential hemocyte counts were recorded over time in larvae, after they were injected with B. bassiana conidia. Additionally, hemocyte-mediated phagocytosis and nodulation were initiated in the hemolymph of larvae from the B. bassiana conidia challenge. The introduction of DEAE-Sepharose Fast Flow beads stained with Congo red also induced a strong encapsulation response in the larval hemolymph. Our observations unravel the occurrence of phagocytosis, nodulation and encapsulation in the hemocoel of YPM larvae to fight against the fungal infection, and offer the first insight into the YPM immune system.
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Affiliation(s)
- Shaohua Li
- College of Plant Protection, Shandong Agricultural University, Taian 271018, China
| | - Fanghua Liu
- College of Plant Protection, Shandong Agricultural University, Taian 271018, China; College of Life Science, Hebei University, Baoding 071002, China
| | - Zhiwei Kang
- College of Plant Protection, Shandong Agricultural University, Taian 271018, China; College of Life Science, Hebei University, Baoding 071002, China
| | - Xiangdong Li
- College of Plant Protection, Shandong Agricultural University, Taian 271018, China
| | - Yang Lu
- Institute of Plant Protection, Jilin Academy of Agricultural Sciences, Changchun 130033, China
| | - Qiyun Li
- Institute of Plant Protection, Jilin Academy of Agricultural Sciences, Changchun 130033, China
| | - Yunshun Pang
- College of Plant Protection, Shandong Agricultural University, Taian 271018, China
| | - Fangqiang Zheng
- College of Plant Protection, Shandong Agricultural University, Taian 271018, China.
| | - Xiangchu Yin
- College of Plant Protection, Shandong Agricultural University, Taian 271018, China; College of Life Science, Hebei University, Baoding 071002, China.
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5
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Wrońska AK, Kaczmarek A, Kazek M, Boguś MI. Infection of Galleria mellonella (Lepidoptera) Larvae With the Entomopathogenic Fungus Conidiobolus coronatus (Entomophthorales) Induces Apoptosis of Hemocytes and Affects the Concentration of Eicosanoids in the Hemolymph. Front Physiol 2022; 12:774086. [PMID: 35069239 PMCID: PMC8769874 DOI: 10.3389/fphys.2021.774086] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 11/03/2021] [Indexed: 01/11/2023] Open
Abstract
Apoptosis and autophagy, the mechanisms of programmed cell death, play critical roles in physiological and pathological processes in both vertebrates and invertebrates. Apoptosis is also known to play an important role in the immune response, particularly in the context of entomopathogenic infection. Of the factors influencing the apoptotic process during infection, two of the lesser known groups are caspases and eicosanoids. The aim of this study was to determine whether infection by the entomopathogenic soil fungus Conidiobolus coronatus is associated with apoptosis and changes in caspase activity in the hemocytes of Galleria mellonella larvae, and to confirm whether fungal infection may affect eicosanoid levels in the host. Larvae were exposed for 24 h to fully grown and sporulating fungus. Hemolymph was collected either immediately after termination of exposure (F24 group) or 24 h later (F48 group). Apoptosis/necrosis tests were performed in hemocytes using fluorescence microscopy and flow cytometry, while ELISA tests were used to measure eicosanoid levels. Apoptosis and necrosis occurred to the same degree in F24, but necrosis predominated in F48. Fungal infection resulted in caspase activation, increased PGE1, PGE2, PGA1, PGF2α, and 8-iso-PGF2α levels and decreased TXB2 levels, but had no effect on TXA2 or 11-dehydro-TXB2 concentrations. In addition, infected larvae demonstrated significantly increased PLA2 activity, known to be involved in eicosanoid biosynthesis. Our findings indicate that fungal infection simultaneously induces apoptosis in insects and stimulates general caspase activity, and this may be correlated with changes in the concentrations of eicosanoids.
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Affiliation(s)
| | - Agata Kaczmarek
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences, Warsaw, Poland
| | - Michalina Kazek
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences, Warsaw, Poland
| | - Mieczysława Irena Boguś
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences, Warsaw, Poland.,BIOMIBO, Warsaw, Poland
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6
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Czarniewska E, Urbański A, Chowański S, Kuczer M. The long-term immunological effects of alloferon and its analogues in the mealworm Tenebrio molitor. INSECT SCIENCE 2018; 25:429-438. [PMID: 27925389 DOI: 10.1111/1744-7917.12427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 11/07/2016] [Accepted: 11/22/2016] [Indexed: 06/06/2023]
Abstract
The subject of this article is a search for the long-term immunological effects of alloferon and 3 structural analogues of alloferon, which were earlier characterized by the highest pro-apoptotic activity in Tenebrio molitor. The differences in the actions of these peptides on immune response were observed. Alloferon increased nodulation and significantly phenoloxidase activity in the hemolymph of experimentally infected T. molitor. However, [Phe(p-NH2 )1 ]- and [Phe(p-OMe)1 ]-alloferon strongly inhibited cellular and humoral defense of the mealworm against Staphylococcus aureus infection. One day after injection of these peptides, the specific biochemical and morphological hallmarks of apoptosis in bacteria-challenged hemocytes were visible; in contrast, 3 days after peptides injection in all hemocytes, caspase activation was not observed. However, these new, circulating hemocytes differed from the control and the peptide-untreated bacteria-challenged hemocytes. They had an increased adhesion that led to a separation of viable, anucleated fragments of hemocytes that retain the ability to adhere and to form long filopodia. The peptide-induced separation of hemocyte fragments may resemble the formation of platelets in mammals and perhaps play a role in sealing wounds in insects. The results of in vivo studies may suggest a long half-life of studied peptides in the hemolymph of mealworm. Moreover, we showed the importance of the N-terminal histidine residues at position one of the alloferon molecule for its immunological properties in insects. The results obtained here show that alloferon plays pleiotropic functions in insects.
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Affiliation(s)
- Elżbieta Czarniewska
- Department of Animal Physiology and Development Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Arkadiusz Urbański
- Department of Animal Physiology and Development Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Szymon Chowański
- Department of Animal Physiology and Development Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Mariola Kuczer
- Faculty of Chemistry, Wrocław University, Joliot-Curie 14, 50-383 Wrocław, Poland
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7
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Sinotte VM, Freedman SN, Ugelvig LV, Seid MA. Camponotusfloridanus Ants Incur a Trade-Off between Phenotypic Development and Pathogen Susceptibility from Their Mutualistic Endosymbiont Blochmannia. INSECTS 2018; 9:E58. [PMID: 29857577 PMCID: PMC6023366 DOI: 10.3390/insects9020058] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/23/2018] [Accepted: 05/30/2018] [Indexed: 11/21/2022]
Abstract
Various insects engage in microbial mutualisms in which the reciprocal benefits exceed the costs. Ants of the genus Camponotus benefit from nutrient supplementation by their mutualistic endosymbiotic bacteria, Blochmannia, but suffer a cost in tolerating and regulating the symbiont. This cost suggests that the ants face secondary consequences such as susceptibility to pathogenic infection and transmission. In order to elucidate the symbiont's effects on development and disease defence, Blochmannia floridanus was reduced in colonies of Camponotus floridanus using antibiotics. Colonies with reduced symbiont levels exhibited workers of smaller body size, smaller colony size, and a lower major-to-minor worker caste ratio, indicating the symbiont's crucial role in development. Moreover, these ants had decreased cuticular melanisation, yet higher resistance to the entomopathogen Metarhizium brunneum, suggesting that the symbiont reduces the ants' ability to fight infection, despite the availability of melanin to aid in mounting an immune response. While the benefits of improved growth and development likely drive the mutualism, the symbiont imposes a critical trade-off. The ants' increased susceptibility to infection exacerbates the danger of pathogen transmission, a significant risk given ants' social lifestyle. Thus, the results warrant research into potential adaptations of the ants and pathogens that remedy and exploit the described disease vulnerability.
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Affiliation(s)
- Veronica M Sinotte
- Department of Biology, Program of Neuroscience, University of Scranton, Loyola Science Center, Scranton, PA 1851-4699, USA.
- Centre for Social Evolution, Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark.
| | - Samantha N Freedman
- Department of Biology, Program of Neuroscience, University of Scranton, Loyola Science Center, Scranton, PA 1851-4699, USA.
- Department of Pathology, University of Iowa, 1080 Medical Laboratories, 500 Newton Road, Iowa City, IA 52242-8205, USA.
| | - Line V Ugelvig
- Centre for Social Evolution, Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark.
| | - Marc A Seid
- Department of Biology, Program of Neuroscience, University of Scranton, Loyola Science Center, Scranton, PA 1851-4699, USA.
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8
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Richards EH, Dani MP, Lu Y, Butt T, Weaver RJ. Effect of stress on heat shock protein levels, immune response and survival to fungal infection of Mamestra brassicae larvae. JOURNAL OF INSECT PHYSIOLOGY 2017; 96:53-63. [PMID: 27789295 DOI: 10.1016/j.jinsphys.2016.10.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 10/20/2016] [Accepted: 10/20/2016] [Indexed: 06/06/2023]
Abstract
Although the utilisation of fungal biological control agents to kill insect pests is desirable, it is known that the outcome of infection may be influenced by a number of criteria, including whether or not the target insect is stressed. In the current work, topical treatment of larvae of the lepidopteran pest, Mamestra brassicae, with conidia of Beauveria bassiana, followed by a heat stress (HS; 37°C for 1h) 48h later, resulted in a similar level of larval survival to that occurring for no heat stress (No-HS), fungus-treated larvae. By contrast, when the HS was applied 24h after fungal treatment, larval survival was significantly increased, indicating that the HS is protecting the larvae from B. bassiana. Similarly, exposure of larvae to a HS provided protection against Metarhizium brunneum (V275) at 48h (but not 24h) after fungal treatment. To elucidate the mechanism(s) that might contribute to HS-induced increases in larval survival against fungal infection, the effects of a HS on key cellular and humoral immune responses and on the level of selected heat shock proteins (HSP) were assessed. When larvae were kept under control (No HS) conditions, there was no significant difference in the haemocyte number per ml of haemolymph over a 24h period. However, exposure of larvae to a HS, significantly increased the haemocyte density immediately after (t=0h) and 4h after HS compared to the No HS controls, whilst it returned to control levels at t=24h. In addition, in vitro assays indicated that haemocytes harvested from larvae immediately after (0h) and 4h (but not 24h) after a HS exhibited higher rates of phagocytosis of FITC-labelled B. bassiana conidia compared to haemocytes harvested from non-HS larvae. Interestingly, the HS did not appear to increase anti-fungal activity in larval plasma. Western blot analysis using antibodies which cross react with Drosophila melanogaster HSP, resulted in a relatively strong signal for HSP 70 and HSP 90 from extracts of 50,000 and 100,000haemocytes, respectively, harvested from No-HS larvae. By contrast, for HSP 60, a lysate derived from 200,000haemocytes resulted in a relatively weak signal. When larvae were exposed to a HS, the level of all three HSP increased compared to the No HS control 4h and 16h after the HS. However, 24h after treatment, any heat stress-mediated increase in HSP levels was minimal and not consistently detected. Similar results were obtained when HSP 90, 70, and 60 levels were assessed in fat body harvested from heat stressed and non-heat stressed larvae. With regard to HSP 27, no signal was obtained even when a lysate from 200,000haemocytes or three times the amount of fat body were processed, suggesting that the anti-HSP 27 antibody utilised does not cross-react with the M. brassicae HSP. The results suggest that a HS-mediated increase in haemocyte density and phagocytic activity, together with an upregulation of HSP 90 and 70, may contribute to increasing the survival of M. brassicae larvae treated with B. bassiana and M. brunneum (V275).
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Affiliation(s)
| | - M P Dani
- Fera, Sand Hutton, York YO41 1LZ, UK
| | - Y Lu
- Fera, Sand Hutton, York YO41 1LZ, UK
| | - T Butt
- Department of Biosciences, College of Science, Swansea University, Singleton Park, Swansea SA2 8PP, UK
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9
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Eicosanoids mediate Galleria mellonella immune response to hemocoel injection of entomopathogenic nematode cuticles. Parasitol Res 2015; 115:597-608. [DOI: 10.1007/s00436-015-4776-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Accepted: 10/06/2015] [Indexed: 11/25/2022]
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10
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Ramirez JL, de Almeida Oliveira G, Calvo E, Dalli J, Colas RA, Serhan CN, Ribeiro JM, Barillas-Mury C. A mosquito lipoxin/lipocalin complex mediates innate immune priming in Anopheles gambiae. Nat Commun 2015; 6:7403. [PMID: 26100162 PMCID: PMC4542143 DOI: 10.1038/ncomms8403] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 05/05/2015] [Indexed: 12/11/2022] Open
Abstract
Exposure of Anopheles gambiae mosquitoes to Plasmodium infection enhances the ability of their immune system to respond to subsequent infections. However, the molecular mechanism that allows the insect innate immune system to ‘remember' a previous encounter with a pathogen has not been established. Challenged mosquitoes constitutively release a soluble haemocyte differentiation factor into their haemolymph that, when transferred into Naive mosquitoes, also induces priming. Here we show that this factor consists of a Lipoxin/Lipocalin complex. We demonstrate that innate immune priming in mosquitoes involves a persistent increase in expression of Evokin (a lipid carrier of the lipocalin family), and in their ability to convert arachidonic acid to lipoxins, predominantly Lipoxin A4. Plasmodium ookinete midgut invasion triggers immune priming by inducing the release of a mosquito lipoxin/lipocalin complex. A soluble factor induced by Plasmodium infection promotes hemocyte differentiation and increases mosquitoe resistance to subsequent infections. Here the authors show that this factor consists of a Lipocalin/Lipoxin A4 complex, and that insects can metabolize arachidonic acid to produce lipoxins.
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Affiliation(s)
- Jose Luis Ramirez
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
| | - Giselle de Almeida Oliveira
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
| | - Eric Calvo
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
| | - Jesmond Dalli
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Romain A Colas
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Charles N Serhan
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Jose M Ribeiro
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
| | - Carolina Barillas-Mury
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
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11
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Ramos S, Custódio A, Silveira H. Anopheles gambiae eicosanoids modulate Plasmodium berghei survival from oocyst to salivary gland invasion. Mem Inst Oswaldo Cruz 2014; 109:668-71. [PMID: 25141285 PMCID: PMC4156460 DOI: 10.1590/0074-0276140098] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 06/30/2014] [Indexed: 11/21/2022] Open
Abstract
Eicosanoids affect the immunity of several pathogen/insect models, but their role on
the Anopheles gambiae response to Plasmodium is
still unknown. Plasmodium berghei-infected mosquitoes were injected
with an eicosanoid biosynthesis inhibitor, indomethacin (IN), or a substrate,
arachidonic acid (AA), at day 7 or day 12 post-infection (p.i.). Salivary gland
invasion was evaluated by sporozoite counts at day 21 p.i. IN promoted infection upon
sporozoite release from oocysts, but inhibited infection when sporozoites were still
maturing within the oocysts, as observed by a reduction in the number of sporozoites
reaching the salivary glands. AA treatment had the opposite effect. We show for the
first time that An. gambiae can modulate parasite survival through
eicosanoids by exerting an antagonistic or agonistic effect on the parasite,
depending on its stage of development.
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Affiliation(s)
- Susana Ramos
- Unidade de Ensino e Investigação de Parasitologia Médica, Centro de Malária e Outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Ana Custódio
- Unidade de Ensino e Investigação de Parasitologia Médica, Centro de Malária e Outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Henrique Silveira
- Unidade de Ensino e Investigação de Parasitologia Médica, Centro de Malária e Outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Portugal
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12
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Defferrari MS, da Silva R, Orchard I, Carlini CR. Jack bean (Canavalia ensiformis) urease induces eicosanoid-modulated hemocyte aggregation in the Chagas' disease vector Rhodnius prolixus. Toxicon 2014; 82:18-25. [PMID: 24561121 DOI: 10.1016/j.toxicon.2014.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 01/29/2014] [Accepted: 02/04/2014] [Indexed: 12/25/2022]
Abstract
Ureases are multifunctional proteins that display biological activities independently of their enzymatic function, such as induction of exocytosis and insecticidal effects. Rhodnius prolixus, a major vector of Chagas' disease, is a model for studies on the entomotoxicity of jack bean urease (JBU). We have previously shown that JBU induces the production of eicosanoids in isolated tissues of R. prolixus. In insects, the immune response comprises cellular and humoral reactions, and is centrally modulated by eicosanoids. Cyclooxygenase products signal immunity in insects, mainly cellular reactions, such as hemocyte aggregation. In searching for a link between JBU's toxic effects and immune reactions in insects, we have studied the effects of this toxin on R. prolixus hemocytes. JBU triggers aggregation of hemocytes after injection into the hemocoel and when applied to isolated cells. On in vitro assays, the eicosanoid synthesis inhibitors dexamethasone (phospholipase A2 indirect inhibitor) and indomethacin (cyclooxygenase inhibitor) counteracted JBU's effect, indicating that eicosanoids, more specifically cyclooxygenase products, are likely to mediate the aggregation response. Contrarily, the inhibitors esculetin and baicalein were inactive, suggesting that lipoxygenase products are not involved in JBU's effect. Extracellular calcium was also necessary for JBU's effect, in agreement to other cell models responsive to ureases. A progressive darkening of the medium of JBU-treated hemocytes was observed, suggestive of a humoral response. JBU was immunolocalized in the cultured cells upon treatment along with cytoskeleton damage. The highest concentration of JBU tested on cultured cells also led to nuclei aggregation of adherent hemocytes. This is the first time urease has been shown to affect insect hemocytes, contributing to our understanding of the entomotoxic mechanisms of action of this protein.
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Affiliation(s)
- M S Defferrari
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Institute of Biosciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
| | - R da Silva
- Department of Biology, McMaster University, Hamilton, ON, Canada.
| | - I Orchard
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada.
| | - C R Carlini
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Institute of Biosciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Instituto do Cérebro - InsCer, Pontificia Universidade Católica do Rio Grande do Sul, and Department of Biophysics, Biosciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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Büyükgüzel E. Eicosanoids mediate cellular immune response and phenoloxidase reaction to viral infection in adult Pimpla turionellae. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2012; 81:20-33. [PMID: 22622947 DOI: 10.1002/arch.21031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Nodulation is the predominant insect cellular immune response to microbial infections. We posed the hypothesis that parasitoid insects in their adulthood express melanotic nodulation reactions to viral challenge and that eicosanoids mediate nodulation reactions and phenoloxidase (PO) activation in response to viral challenge. To test this idea, we injected Pimpla turionellae adults with indomethacin, a nonsteroidal anti-inflammatory drug, immediately prior to intrahemocoelic injection of Bovine herpes simplex virus-1 (BHSV-1). Treating newly emerged adults of P. turionellae with BHSV-1 induced nodulation reactions, and decreased PO activity at high viral doses. Relative to vehicle-treated controls, indomethacin-treated adults produced significantly reduced numbers of nodules following viral infection (down from approximately 21 nodules per adult to less than six nodules per adult). In addition to injection treatments, increasing dietary indomethacin dosages (from 0.01% to 0.1%) were associated with decreasing nodulation (by six-fold) and PO (by about three-fold) reactions to BHSV-1 injection. Wasp adults orally fed with the lowest dietary indomethacin concentration (0.001%) expressed significantly increased PO activity (1.45 unit/min/mg protein) while nodulation reaction was not affected in response to viral challenge compared to control adults. We infer from these findings that cyclooxygenase (COX) products, at least prostaglandins, mediate nodulation response and PO action to viral infection in adults of these highly specialized insects.
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Affiliation(s)
- Ender Büyükgüzel
- Department of Biology, Faculty of Arts and Science, Zonguldak Karaelmas University, İncivez, Zonguldak, Turkey.
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Park JA, Kim Y. Phospholipase A2 inhibitors in bacterial culture broth enhance pathogenicity of a fungus Nomuraea rileyi. J Microbiol 2012; 50:644-51. [DOI: 10.1007/s12275-012-2108-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 04/25/2012] [Indexed: 12/29/2022]
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15
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Park JA, Kim Y. Eicosanoid biosynthesis is activated via Toll, but not Imd signal pathway in response to fungal infection. J Invertebr Pathol 2012; 110:382-8. [DOI: 10.1016/j.jip.2012.04.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 03/27/2012] [Accepted: 04/28/2012] [Indexed: 11/17/2022]
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16
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Eicosanoids: Exploiting Insect Immunity to Improve Biological Control Programs. INSECTS 2012; 3:492-510. [PMID: 26466540 PMCID: PMC4553607 DOI: 10.3390/insects3020492] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 04/24/2012] [Accepted: 05/09/2012] [Indexed: 01/30/2023]
Abstract
Insects, like all invertebrates, express robust innate, but not adaptive, immune reactions to infection and invasion. Insect immunity is usually resolved into three major components. The integument serves as a physical barrier to infections. Within the hemocoel, the circulating hemocytes are the temporal first line of defense, responsible for clearing the majority of infecting bacterial cells from circulation. Specific cellular defenses include phagocytosis, microaggregation of hemocytes with adhering bacteria, nodulation and encapsulation. Infections also stimulate the humoral component of immunity, which involves the induced expression of genes encoding antimicrobial peptides and activation of prophenoloxidase. These peptides appear in the hemolymph of challenged insects 6-12 hours after the challenge. Prostaglandins and other eicosanoids are crucial mediators of innate immune responses. Eicosanoid biosynthesis is stimulated by infection in insects. Inhibition of eicosanoid biosynthesis lethally renders experimental insects unable to clear bacterial infection from hemolymph. Eicosanoids mediate specific cell actions, including phagocytosis, microaggregation, nodulation, hemocyte migration, hemocyte spreading and the release of prophenoloxidase from oenocytoids. Some invaders have evolved mechanisms to suppress insect immunity; a few of them suppress immunity by targeting the first step in the eicosanoid biosynthesis pathways, the enzyme phospholipase A₂. We proposed research designed to cripple insect immunity as a technology to improve biological control of insects. We used dsRNA to silence insect genes encoding phospholipase A₂, and thereby inhibited the nodulation reaction to infection. The purpose of this article is to place our view of applying dsRNA technologies into the context of eicosanoid actions in insect immunity. The long-term significance of research in this area lies in developing new pest management technologies to contribute to food security in a world with a rapidly growing human population.
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Richards EH, Bradish H, Dani MP, Pietravalle S, Lawson A. Recombinant immunosuppressive protein from Pimpla hypochondrica venom (rVPr1) increases the susceptibility of Mamestra brassicae larvae to the fungal biological control agent, Beauveria bassiana. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2011; 78:119-131. [PMID: 21948634 DOI: 10.1002/arch.20447] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Although fungi are used to control a variety of insect pests, it is accepted that their usage could be increased if their efficacy was greater. The outcome of the interaction of a fungus and a pest insect may be influenced by a number of criteria, including the ability of the insect to mount effective immune responses against the pathogen. In view of this, we aimed to determine if a recombinant immunosuppressive wasp venom protein (rVPr1) can increase the susceptibility of larvae of the lepidopteran pest, Mamestra brassicae, to the fungal biological control agent, Beauveria bassiana. Bioassays indicated that when larvae were injected with 3.5 µl of rVPr1 and 100 B. bassiana conidia (combined injection assays), a significant reduction in survival of larvae occurred compared with each treatment on its own (P=0.006). Similar results were obtained when larvae were dipped in a solution containing 3 × 10(6) B. bassiana conidia per ml and then injected with 3.5 µl of rVPr1 2 days later (topical application assays), (P<0.001). These results indicate that rVPr1 can increase the efficacy of B. bassiana toward a lepidopteran pest, and are discussed within the context of insect immune responses and integrated pest management.
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Affiliation(s)
- Elaine H Richards
- The Food and Environment Research Agency, Sand Hutton, York, United Kingdom.
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Rohlfs M, Churchill ACL. Fungal secondary metabolites as modulators of interactions with insects and other arthropods. Fungal Genet Biol 2010; 48:23-34. [PMID: 20807586 DOI: 10.1016/j.fgb.2010.08.008] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 08/05/2010] [Accepted: 08/22/2010] [Indexed: 12/19/2022]
Abstract
Fungi share a diverse co-evolutionary history with animals, especially arthropods. In this review, we focus on the role of secondary metabolism in driving antagonistic arthropod-fungus interactions, i.e., where fungi serve as a food source to fungal grazers, compete with saprophagous insects, and attack insects as hosts for growth and reproduction. Although a wealth of studies on animal-fungus interactions point to a crucial role of secondary metabolites in deterring animal feeding and resisting immune defense strategies, causal evidence often remains to be provided. Moreover, it still remains an unresolved puzzle as to what extent the tight regulatory control of secondary metabolite formation in some model fungi represents an evolved chemical defense system favored by selective pressure through animal antagonists. Given these gaps in knowledge, we highlight some co-evolutionary aspects of secondary metabolism, such as induced response, volatile signaling, and experimental evolution, which may help in deciphering the ecological importance and evolutionary history of secondary metabolite production in fungi.
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Affiliation(s)
- Marko Rohlfs
- J.F. Blumenbach Institute of Zoology and Anthropology, Georg-August University of Göttingen, Germany.
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Büyükgüzel E, Hyršl P, Büyükgüzel K. Eicosanoids mediate hemolymph oxidative and antioxidative response in larvae of Galleria mellonella L. Comp Biochem Physiol A Mol Integr Physiol 2010; 156:176-83. [DOI: 10.1016/j.cbpa.2010.01.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Revised: 01/24/2010] [Accepted: 01/24/2010] [Indexed: 11/26/2022]
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Garcia ES, Castro DP, Figueiredo MB, Genta FA, Azambuja P. Trypanosoma rangeli: a new perspective for studying the modulation of immune reactions of Rhodnius prolixus. Parasit Vectors 2009; 2:33. [PMID: 19615044 PMCID: PMC2719633 DOI: 10.1186/1756-3305-2-33] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 07/17/2009] [Indexed: 11/11/2022] Open
Abstract
Insects are exposed to a wide range of microorganisms (bacteria, fungi, parasites and viruses) and have interconnected powerful immune reactions. Although insects lack an acquired immune system they have well-developed innate immune defences that allow a general and rapid response to infectious agents. Over the last few decades we have observed a dramatic increase in the knowledge of insect innate immunity, which relies on both humoral and cellular responses. However, innate reactions to natural insect pathogens and insect-transmitted pathogens, such as parasites, still remain poorly understood. In this review, we briefly introduce the general immune system of insects and highlight our current knowledge of these reactions focusing on the interactions of Trypanosoma rangeli with Rhodnius prolixus, an important model for innate immunity investigation.
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Affiliation(s)
- Eloi S Garcia
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Avenida Brasil 4365, Rio de Janeiro, 21045-900, RJ, Brazil.
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Figueiredo MB, Genta FA, Garcia ES, Azambuja P. Lipid mediators and vector infection: Trypanosoma rangeli inhibits Rhodnius prolixus hemocyte phagocytosis by modulation of phospholipase A2 and PAF-acetylhydrolase activities. JOURNAL OF INSECT PHYSIOLOGY 2008; 54:1528-1537. [PMID: 18835273 DOI: 10.1016/j.jinsphys.2008.08.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 08/11/2008] [Accepted: 08/21/2008] [Indexed: 05/26/2023]
Abstract
In this work we investigated the effects of Trypanosoma rangeli infection through a blood meal on the hemocyte phagocytosis in experiments using the 5th instar larvae of Rhodnius prolixus. Hemocyte phagocytic activity was strongly blocked by oral infection with the parasites. In contrast, hemocyte phagocytosis inhibition caused by T. rangeli infection was rescued by exogenous arachidonic acid (20 microg/insect) or platelet activating factor (PAF; 1 microg/insect) applied by hemocelic injection. Following the oral infection with the protozoan we observed significant attenuation of phospholipase A2 (PLA2) activities in R. prolixus hemocytes (cytosolic PLA2: cPLA2, secreted PLA2: sPLA2 and Ca+2-independent PLA2: iPLA2) and enhancement of sPLA2 activities in cell-free hemolymph. At the same time, the PAF-acetyl hydrolase (PAF-AH) activity in the cell-free hemolymph increased considerably. Our results suggest that T. rangeli infection depresses eicosanoid and insect PAF analogous (iPAF) pathways giving support to the role of PLA2 in the regulation of arachidonic acid and iPAF biosynthesis and of PAF-AH by reducing the concentration of iPAF in R. prolixus. This illustrates the ability of T. rangeli to modulate the immune responses of R. prolixus to favor its own multiplication in the hemolymph.
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Affiliation(s)
- Marcela B Figueiredo
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz, Av. Brasil 4365, Rio de Janeiro 21045-900, RJ, Brazil
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Figueiredo MB, Garcia ES, Azambuja P. Blockades of phospholipase A(2) and platelet-activating factor receptors reduce the hemocyte phagocytosis in Rhodnius prolixus: in vitro experiments. JOURNAL OF INSECT PHYSIOLOGY 2008; 54:344-350. [PMID: 18036540 DOI: 10.1016/j.jinsphys.2007.10.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 10/09/2007] [Accepted: 10/12/2007] [Indexed: 05/25/2023]
Abstract
The hemocytes phagocytosis in response to microorganisms may play an important role in the cellular immune responses of insects. Here, we have evaluated the effects of the platelet-activating factor (PAF) and eicosanoids in the phagocytosis of hemocyte monolayers of Rhodnius prolixus to the yeast Saccharomyces cerevisiae. Experiments showed that the phagocytosis of yeast cells by Rhodnius hemocytes is very efficient in both controls and cells treated with PAF and arachidonic acid. Phagocytosis of yeast particles is significantly blocked when the specific phopholipase A(2) inhibitor, dexamethasone, is applied on the hemocytes. By contrast, dexamethasone-pretreated hemocyte monolayers exhibit a drastic increase in the quantity of yeast cell-hemocyte internalization when the cells are treated by arachidonic acid. In addition, phagocytosis presents significant reduction in hemocyte monolayers treated with a specific PAF receptor antagonist, WEB 2086. Nevertheless, inhibition of phagocytosis with WEB 2086 is counteracted by the treatment of the hemocyte monolayers with PAF. In conclusion, phagocytosis of yeast cells by hemocytes is related to the activation of PAF receptors and eicosanoid pathways in the bloodsucking bug, R. prolixus.
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Affiliation(s)
- Marcela B Figueiredo
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
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Shrestha S, Kim Y. Eicosanoids mediate prophenoloxidase release from oenocytoids in the beet armyworm Spodoptera exigua. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2008; 38:99-112. [PMID: 18070669 DOI: 10.1016/j.ibmb.2007.09.013] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Revised: 09/09/2007] [Accepted: 09/24/2007] [Indexed: 05/25/2023]
Abstract
Phenoloxidase (PO) plays a critical role in insect immune reactions especially to form melanotic encapsulation and phagocytosis by hemocytes. PO is an active form of prophenoloxidase (PPO) after proteolytic cleavage by serine proteinase(s). It has been suggested that eicosanoids are implicated in PPO activation in the beet armyworm, Spodoptera exigua. However, it is not clear how eicosanoids mediate the reaction cascade of PPO activation. This study analyzed the PPO activation mediated by eicosanoids at both transcriptional and post-transcriptional levels. A cDNA encoding PPO (SePPO) was cloned from the hemocytes of S. exigua and its putative amino acid sequence shared homology with PPO-2 of other lepidopteran insects. Its expression was specific only to hemocytes and inducible in response to bacterial challenge. Eicosanoid biosynthesis inhibitors did not influence the gene expression of SePPO. Most SePPO proteins were located in a specific hemocyte type, oenocytoids, which were subjected to cell rupture to release the cellular contents in response to bacterial challenge. There was a significant negative correlation between PO activity and intact oenocytoid density. Interestingly, this cell rupture to release SePPO from oenocytoids was significantly inhibited in the larvae infected with the phospholipase A2-inhibiting bacterium, Xenorhabdus nematophila, which was resumed on addition of eicosanoid biosynthesis precursor, arachidonic acid. Furthermore, oenocytoids exposed to eicosanoid biosynthesis inhibitors such as dexamethasone and bromophenacyl bromide showed significant reduction in cell rupture. Prostaglandins, not lipoxygenase products appeared to be implicated in the cell rupture. These results indicate that eicosanoids mediate SePPO activation only at the post-transcriptional level by inducing release of PPO from oenocytoids through cell rupture.
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Affiliation(s)
- Sony Shrestha
- Department of Bioresource Science, Andong National University, Andong 760-749, Republic of Korea
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Stanley D, Shapiro M. Eicosanoid biosynthesis inhibitors increase the susceptibility of Lymantria dispar to nucleopolyhedrovirus LdMNPV. J Invertebr Pathol 2007; 95:119-24. [PMID: 17386933 DOI: 10.1016/j.jip.2007.02.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Revised: 01/24/2007] [Accepted: 02/06/2007] [Indexed: 11/24/2022]
Abstract
Eighteen pharmaceutical inhibitors of eicosanoid biosynthesis were tested for their effects on gypsy moth, Lymantria dispar and its susceptibility to the nucleopoly-hedrovirus LdMNPV. None of the inhibitors tested had any detrimental effects upon larval growth and development. Treatment with nine inhibitor/NPV combinations (e.g., bromophenacylbromide, clotrimazole, dexamethasone, esculetin, flufenamic acid, indomethacin, nimesulide, sulindac, tolfenamic acid) resulted in 3.5- to 6.6-fold reductions in LC(50)s. Larvae treated with several other COX inhibitors did not yield significant LC(50) reductions. We infer that eicosanoids act in insect defense responses to viral infection. Eicosanoids may act at three levels of insect immune reactions to viral infection, organismal (febrile response), cellular (hemocytic microaggregation, nodulation and plasmatocytes spreading reactions) and intracellular level (mechanisms responsible for insect permissiveness to viral replication).
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Affiliation(s)
- David Stanley
- USDA/Agricultural Research Service, Biological Control of Insects Research Laboratory, Columbia, MO 65203, USA.
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Büyükgüzel E, Tunaz H, Stanley D, Büyükgüzel K. Eicosanoids mediate Galleria mellonella cellular immune response to viral infection. JOURNAL OF INSECT PHYSIOLOGY 2007; 53:99-105. [PMID: 17161422 DOI: 10.1016/j.jinsphys.2006.10.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Revised: 10/27/2006] [Accepted: 10/30/2006] [Indexed: 05/12/2023]
Abstract
Nodulation is the predominant insect cellular immune response to bacterial and fungal infections and it can also be induced by some viral infections. Treating seventh instar larvae of greater wax moth Galleria mellonella with Bovine herpes simplex virus-1 (BHSV-1) induced nodulation reactions in a dose-dependent manner. Because eicosanoids mediate nodulation reactions to bacterial and fungal infection, we hypothesized that eicosanoids also mediate nodulation reactions to viral challenge. To test this idea, we injected G. mellonella larvae with indomethacin, a nonsteroidal anti-inflammatory drug immediately prior to intrahemocoelic injection of BHSV-1. Relative to vehicle-treated controls, indomethacin-treated larvae produced significantly reduced numbers of nodules following viral infection (down from approximately 190 nodules/larva to <50 nodules/larva). In addition to injection treatments, increasing dietary indomethacin dosages (from 0.01% to 1%) were associated with decreasing nodulation (by 10-fold) and phenoloxidase activity (by 3-fold) reactions to BHSV-1 injection. We infer from these findings that cyclooxygenase products, prostaglandins, mediate nodulation response to viral infection in G. mellonella.
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Affiliation(s)
- Ender Büyükgüzel
- Department of Biology, Faculty of Arts and Science, Karaelmas University, Zonguldak, Turkey
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Tunaz H. Eicosanoid biosynthesis inhibitors influence mortality of Pieris brassicae larvae co-injected with fungal conidia. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2006; 63:93-100. [PMID: 17048247 DOI: 10.1002/arch.20145] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Influence of fungal species (conidia spores) on mortality of Pieris brassicae larvae differed when injected into the larvae. The effects of B. bassiana (ARSEF-1151) were expressed in a conidial dose-dependent manner on mortality of the larvae. An increased and faster mortality of the larvae followed B. bassiana (ARSEF-1151) infection when the spores were co-injected with the eicosanoid biosynthesis inhibitors (dexamethasone, naproxen, phenidone, esculetin). These compounds express different modes of action. These lethal effects were reversed when dexamethasone was injected with eicosanoid precursor arachidonic acid (20:4n-6). Nodulation is the predominant cellular reaction to bacterial and fungal injection in insects. Injection of each of five fungal species showed that nodulation intensity varies according to infecting fungal species. These findings support the idea that virulent effects of entomopathogenic, fungal species can be increased when P. brassicae immune systems are suppressed.
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Affiliation(s)
- Hasan Tunaz
- Department of Plant Protection, Faculty of Agriculture, Kahramanmaras Sütçü Imam University, Kahramanmaras, Turkey.
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Kolss M, Kraaijeveld AR, Mery F, Kawecki TJ. No trade-off between learning ability and parasitoid resistance in Drosophila melanogaster. J Evol Biol 2006; 19:1359-63. [PMID: 16780538 DOI: 10.1111/j.1420-9101.2005.01068.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Learning ability and immunity to parasites are linked at the physiological level in several insect species. The aim of this work was to investigate the relationship between learning and immunity at an evolutionary level. We tested whether selection for improved learning ability in Drosophila melanogaster led to changes in parasitoid resistance as a correlated response. Similarly, we assayed whether selection for better parasitoid resistance led to a change in learning ability. There was no significant difference between selected and control lines in either case; the estimated confidence intervals for the differences indicate that a trade-off relationship is unlikely.
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Affiliation(s)
- M Kolss
- Section of Ecology and Evolution, Department of Biology, University of Fribourg, Fribourg, Switzerland
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Delaporte M, Soudant P, Moal J, Giudicelli E, Lambert C, Séguineau C, Samain JF. Impact of 20∶4n−6 supplementation on the fatty acid composition and hemocyte parameters of the pacific oyster crassostrea gigas. Lipids 2006; 41:567-76. [PMID: 16981435 DOI: 10.1007/s11745-006-5006-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Arachidonic acid (20:4n-6, ArA) and its eicosanoid metabolites have been demonstrated to be implicated in immune functions of vertebrates, fish, and insects. Thus, the aim of this study was to assess the impact of ArA supplementation on the FA composition and hemocyte parameters of oysters Crassostrea gigas. Oyster dietary conditioning consisted of direct addition of ArA solutions at a dose of 0, 0.25, or 0.41 microg ArA per mL of seawater into tanks in the presence or absence of T-Iso algae. Results showed significant incorporation of ArA into gill polar lipids when administered with algae (up to 19.7%) or without algae (up to 12.1%). ArA supplementation led to an increase in hemocyte numbers, phagocytosis, and production of reactive oxygen species by hemocytes from ArA-supplemented oysters. Moreover, the inhibitory effect of Vibrio aestuarianus extracellular products on the adhesive proprieties of hemocytes was lessened in oysters fed ArA-supplemented T-Iso. All changes in oyster hemocyte parameters reported in the present study suggest that ArA and/or eicosanoid metabolites affect oyster hemocyte functions.
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Affiliation(s)
- Maryse Delaporte
- UMR 100 Physiologie and Ecophysiologie des Mollusques Marins, Centre IFREMER de Brest, BP70, 29280 Plouzané, France
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Riddell CE, Mallon EB. Insect psychoneuroimmunology: immune response reduces learning in protein starved bumblebees (Bombus terrestris). Brain Behav Immun 2006; 20:135-8. [PMID: 16084688 DOI: 10.1016/j.bbi.2005.06.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Revised: 06/27/2005] [Accepted: 06/27/2005] [Indexed: 11/23/2022] Open
Abstract
It is well established in vertebrates that there are many intricate interactions between the immune system and the nervous system. Here, we present behavioural evidence indicating a link between the immune system and the nervous system in insects. We show that otherwise non-infected bumblebees whose immune systems were challenged by a non-pathogenic immunogenic elicitor (lipopolysaccharide) have reduced abilities to learn or recall a memory in a classical conditioning paradigm. There is evidence that protein is intricately involved as this immune induced reduction in memory only becomes apparent after the bees are deprived of pollen (their only protein sources).
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Stanley D. Prostaglandins and other eicosanoids in insects: biological significance. ANNUAL REVIEW OF ENTOMOLOGY 2006; 51:25-44. [PMID: 16332202 DOI: 10.1146/annurev.ento.51.110104.151021] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Prostaglandins and other eicosanoids are oxygenated metabolites of certain polyunsaturated fatty acids. These compounds are well known for their important actions in mammalian physiology and disease. Recent work has revealed the presence and biological actions of eicosanoids in insects and many other invertebrate animals. In insects, eicosanoids mediate cellular immunity to microbial and metazoan challenge. Notably, some infectious organisms secrete factors responsible for impairing host insect immune reactions by inhibiting biosynthesis of eicosanoids. Eicosanoids also act in insect reproductive biology, in ion transport physiology, and in fever response to infection as well as in protein exocytosis in tick salivary glands. Aside from ongoing actions in homeostasis, certain eicosanoid actions occur at crucial points in insect life histories, such as during infectious challenge and important events in reproduction.
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Affiliation(s)
- David Stanley
- USDA/ARS, Biological Control of Insects Research Laboratory, Columbia, Missouri 65203, USA.
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Miller JS. Eicosanoids influence in vitro elongation of plasmatocytes from the tobacco hornworm, Manduca sexta. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2005; 59:42-51. [PMID: 15822094 DOI: 10.1002/arch.20052] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Nodule formation is the predominant insect cellular defense reaction to bacterial challenges, responsible for clearing the largest proportion of infecting bacteria from hemolymph circulation. Hemocyte spreading behavior is a critical step in the nodulation process. It has been suggested that eicosanoids mediate several steps in the process. However, the influence of eicosanoids on hemocyte spreading has not been investigated in detail. To test the hypothesis that eicosanoids mediate hemocyte spreading behavior, I treated larvae of the tobacco hornworm, Manduca sexta, with eicosanoid biosynthesis inhibitors and later assessed plasmatocyte elongation on glass slides. Plasmatocytes from larvae treated with dexamethasone did not elongate to the extent of plasmatocytes from untreated control larvae. The dexamethasone effect on plasmatocyte elongation was expressed in a dose-dependent manner and was reversed by injecting dexamethasone-treated larvae with the eicosanoid-precursor fatty acid, arachidonic acid. Palmitic acid, which is not substrate for eicosanoid biosynthesis, did not reverse the influence of dexamethasone on plasmatocyte elongation. Finally, plasmatocytes from larvae treated with a range of eicosanoid biosynthesis inhibitors did not elongate to the extent of plasmatocytes from control larvae. Plasmatocyte width did not appear to be influenced in this study. These findings strongly support the idea that insect plasmatocyte elongation is influenced by eicosanoids.
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Affiliation(s)
- Jon S Miller
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA.
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Franssens V, Simonet G, Bronckaers A, Claeys I, De Loof A, Vanden Broeck J. Eicosanoids mediate the laminarin-induced nodulation response in larvae of the flesh fly, Neobellieria bullata. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2005; 59:32-41. [PMID: 15822095 DOI: 10.1002/arch.20053] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Insects have a highly developed innate immune system, including humoral and cellular components. The cellular immune responses refer to hemocyte-mediated processes such as phagocytosis, nodulation, and encapsulation. Nodulation is considered the predominant defense reaction to infection in insects. Treating third instar larvae of the grey flesh fly, Neobellieria bullata, with laminarin (beta-1,3-glucan, a typical component of fungal cell walls) induced nodulation in a dose-dependent manner. This reaction was initiated very soon after injection and reached its maximal response level after 4 h. The nodules were not randomly distributed in the hemocoel, but were concentrated around the crop. The possible role of eicosanoids in this nodulation process was determined by treating larvae with the phospholipase A(2) inhibitor, dexamethasone, the cyclooxygenase inhibitor, naproxen, and the lipoxygenase inhibitor, esculetin. Both dexamethasone and naproxen significantly impaired the ability of N. bullata larvae to form nodules in response to laminarin. Supplying dexamethasone-treated larvae with the eicosanoid precursor, arachidonic acid, restored the full response. On the other hand, treating larvae with esculetin did not influence the formation of nodules in response to laminarin. This is the first study that demonstrates the occurrence of a laminarin-induced nodulation response in Diptera. Phospholipase A(2) and cyclooxygenase activities, both involved in prostaglandin biosynthesis, appear to play an important role in the regulation of this process.
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Affiliation(s)
- Vanessa Franssens
- Laboratory of Developmental Physiology, Genomics and Proteomics, Department of Animal Physiology and Neurobiology, Zoological Institute, K.U. Leuven, Naamsestraat 59, B-3000 Leuven, Belgium
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Dean P, Potter U, Richards EH, Edwards JP, Charnley AK, Reynolds SE. Hyperphagocytic haemocytes in Manduca sexta. JOURNAL OF INSECT PHYSIOLOGY 2004; 50:1027-1036. [PMID: 15607505 DOI: 10.1016/j.jinsphys.2004.09.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2004] [Revised: 08/11/2004] [Accepted: 09/09/2004] [Indexed: 05/24/2023]
Abstract
We have discovered a new type of haemocyte in the larval stage of the tobacco hornworm moth Manduca sexta that has extreme phagocytic ability; each cell can engulf up to 500 bacteria. This level of phagocytosis may be unprecedented among animal cells. Although these hyperphagocytic cells (HP) only represent about 1% of the circulating haemocytes, they are responsible for sequestering the majority of the bacteria by circulating haemocytes when non-pathogenic, heat-killed Escherichia coli are injected into the haemolymph. Extreme phagocytosis by HP is not limited to Gram-negative bacteria since heat-killed Staphylococcus aureus as well as positively and negatively charged microspheres are also highly phagocytosed. Evidence is presented to show that phagocytosis by HP is involved in the early stages of nodule formation in infected insects. In addition, HP are also present in non-infected insects, characterised by their distinctive spreading morphology, which becomes impaired following hyperphagocytosis of bacteria. This is the first time that a dedicated "professional" phagocytic class of haemocyte has been reported for an invertebrate. The importance of these specialised cell types in the M. sexta immune response and their role in nodule formation is discussed.
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Affiliation(s)
- P Dean
- Department of Pathology and Microbiology, Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK
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Miller JS, Stanley DW. Lipopolysaccharide evokes microaggregation reactions in hemocytes isolated from tobacco hornworms, Manduca sexta. Comp Biochem Physiol A Mol Integr Physiol 2004; 137:285-95. [PMID: 15123202 DOI: 10.1016/j.cbpb.2003.10.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2003] [Revised: 10/02/2003] [Accepted: 10/03/2003] [Indexed: 11/27/2022]
Abstract
Insect cellular immune reactions to bacterial infection include nodule formation. Eicosanoids mediate several cellular actions in the nodulation process, including formation of hemocyte microaggregates, an early step. In previous work, we reported that isolated hemocytes produce and secrete eicosanoids that influence hemocyte behavior in response to bacterial challenge. We also reported that microaggregate formation in response to challenge was mediated by prostaglandins (PGs), but not by products of the lipoxygenase (LOX) pathways. In this paper we describe experiments designed to test the idea that exposing isolated hemocytes to lipopolysaccharide (LPS) evokes formation of hemocyte microaggregates and this cellular action is mediated by PGs. Results show that isolated hemocyte preparations challenged with LPS formed more hemocyte microaggregates than unchallenged preparations (6.9x10(3) microaggregates/ml hemolymph vs. 2.5x10(3) microaggregates/ml hemolymph). LPS challenge stimulated formation of hemocyte microaggregates in a dose dependent manner. Experimental groups pretreated with cyclooxygenase inhibitors produced fewer hemocyte microaggregates in response to LPS challenge than untreated control groups. The formation of hemocyte microaggregates was not influenced by LOX inhibitors. Furthermore, the influence of dexamethasone was reversed by supplementing the experimental groups with the eicosanoid precursor fatty acid molecule, arachidonic acid and PGH(2). Palmitic acid, which is not substrate for eicosanoid biosynthesis, did not reverse the effects of dexamethasone on the formation of microaggregates. The LOX product 5(S)hydroperoxyeicosa-6E,8Z,11Z,14Z-tetraenoic acid also did not reverse the effects of dexamethasone. These results are consistent with similar investigations performed with bacterial suspensions. We infer that isolated hemocyte preparations recognize and react to LPS by forming microaggregates and this reaction is mediated by PGs, but not products of the LOX pathway.
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Affiliation(s)
- Jon S Miller
- Department of Biological Sciences, Northern Illinois University, De Kalb, IL 60115, USA.
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Garcia ES, Machado EMM, Azambuja P. Inhibition of hemocyte microaggregation reactions in Rhodnius prolixus larvae orally infected with Trypanosoma rangeli. Exp Parasitol 2004; 107:31-8. [PMID: 15208035 DOI: 10.1016/j.exppara.2004.03.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2003] [Revised: 02/04/2004] [Accepted: 03/30/2004] [Indexed: 11/15/2022]
Abstract
Hemocoelic inoculation of epimastigotes of Trypanosoma rangeli strain H14 into 5th-instar larvae of Rhodnius prolixus previously fed on blood containing the same parasites, showed reduced number of hemocyte microaggregates in the hemolymph, enhanced number of flagellates in the hemolymph as well as increased mortality of these insects. All these effects were counteracted by combined inoculation of R. prolixus with T. rangeli and arachidonic acid. In vitro assays using hemolymph taken from insects previously fed on blood containing parasites showed that hemocyte microaggregation reactions were also attenuated when T. rangeli is used as inducer of the reaction, and that simultaneous applying T. rangeli with arachidonic counteracted the hemocyte microaggregation inhibition. We suggest that arachidonic acid pathway can be a mediator of hemocyte microaggregation reactions in the hemolymph of insects inoculated with T. rangeli, and that oral infection with this protozoan inhibits the release of arachidonic acid.
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Affiliation(s)
- Eloi S Garcia
- Departamento de Bioquímica e Biologia Molecular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Avenida Brasil 4365, CEP 21045-900 Rio de Janeiro, RJ, Brazil
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Mallon EB, Brockmann A, Schmid-Hempel P. Immune response inhibits associative learning in insects. Proc Biol Sci 2004; 270:2471-3. [PMID: 14667337 PMCID: PMC1691534 DOI: 10.1098/rspb.2003.2456] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In vertebrates, it is well established that there are many intricate interactions between the immune system and the nervous system, and vice versa. Regarding insects, until now little has been known about the link between these two systems. Here, we present behavioural evidence indicating a link between the immune system and the nervous system in insects. We show that otherwise non-infected honeybees whose immune systems are challenged by a non-pathogenic immunogenic elicitor lipopolysaccharide (LPS) have reduced abilities to associate an odour with sugar reward in a classical conditioning paradigm. The cost of an immune response therefore not only affects survival of the host, as previously shown, but also everyday behaviour and memory formation.
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Affiliation(s)
- Eamonn B Mallon
- Ecology and Evolution, ETH Zürich, ETH-Zentrum NW, CH-8092 Zürich, Switzerland
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Garcia ES, Machado EMM, Azambuja P. Effects of eicosanoid biosynthesis inhibitors on the prophenoloxidase-activating system and microaggregation reactions in the hemolymph of Rhodnius prolixus infected with Trypanosoma rangeli. JOURNAL OF INSECT PHYSIOLOGY 2004; 50:157-165. [PMID: 15019517 DOI: 10.1016/j.jinsphys.2003.11.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2003] [Revised: 09/04/2003] [Accepted: 11/06/2003] [Indexed: 05/24/2023]
Abstract
Investigations on the effects of eicosanoid biosynthesis inhibitors on the hemocyte microaggregation and prophenoloxidase (proPO)-activating system in the hemolymph, parasitemia and mortality of Rhodnius prolixus infected with Trypanosoma rangeli were performed. Hemocoelic injection of live T. rangeli epimastigotes into fifth-instar larvae of R. prolixus that previously fed on blood containing an inhibitor of phospholipase A(2) (dexamethasone), a specific inhibitor of the cyclooxygenase pathway (indomethacin), and a non-selective lipoxygenase inhibitor (NDGA) (i) reduced the hemocyte microaggregation, (ii) attenuated the proPO system in the hemolymph and (iii) enhanced parasitemia and mortality induced by the parasite challenge in these insects. The effects obtained by dexamethasone administered orally were counteracted by inoculation of the insects with arachidonic acid. We suggest that the infectivity of T. rangeli can be increased by interference with the R. prolixus immune system. This is the first demonstration that the triatomine's immune responses to a parasite infection are modulated by a physiological system that includes eicosanoid biosynthesis.
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Affiliation(s)
- Eloi S Garcia
- Departamento de Bioquímica e Biologia Molecular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Avenida Brasil 4365 Manguinhos, CEP 21045-900, Rio de Janeiro, RJ, Brazil
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38
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Phelps PK, Miller JS, Stanley DW. Prostaglandins, not lipoxygenase products, mediate insect microaggregation reactions to bacterial challenge in isolated hemocyte preparations. Comp Biochem Physiol A Mol Integr Physiol 2003; 136:409-16. [PMID: 14511759 DOI: 10.1016/s1095-6433(03)00199-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Nodulation is the predominant cellular defense reaction to bacterial challenge in insects. Eicosanoids mediate several steps in the nodulation process, including formation of hemocyte microaggregations. Isolated hemocyte preparations synthesize and secrete eicosanoids, which mediate hemocytic immune reactions. Two major groups of eicosanoids are prostaglandins (products of cyclooxygenase pathways) and various products of lipoxygenase pathways. In this study, we test the hypothesis that prostaglandins, but not lipoxygenase products, mediate hemocyte microaggregation reactions in response to bacterial challenge. Our results indicate that isolated hemocyte preparations pretreated with the cyclooxygenase inhibitors indomethacin and naproxen yielded fewer microaggregates than untreated control groups (3.7 x 10(5) microaggregates/ml hemolymph vs. 11.0 x 10(5) microaggregates/ml hemolymph). These inhibitors influence hemocyte microaggregate formation in a dose-dependent manner in treatments ranging from 0 to 200 microM. The lipoxygenase inhibitors esculetin and caffeic acid did not impact the formation of microaggregates in this system. The influence of the phospholipase A(2) inhibitor dexamethasone was reversed by amending experimental (dexamethasone-treated) preparations with prostaglandin H(2), but not prostaglandin D(2), prostaglandin E(2), nor 5(S)-hydroperoxy-6E,8Z,11Z,14Z-eicosatetraenoic acid, a product of the lipoxygenase pathway. We infer that prostaglandins are the primary mediators of microaggregation reactions to bacterial challenge in insect hemocyte preparations.
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Affiliation(s)
- Pamela K Phelps
- Department of Biological Sciences Northern Illinois University, Montgomery Hall 452, DeKalb, IL 60115, USA
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Goldsworthy G, Chandrakant S, Opoku-Ware K. Adipokinetic hormone enhances nodule formation and phenoloxidase activation in adult locusts injected with bacterial lipopolysaccharide. JOURNAL OF INSECT PHYSIOLOGY 2003; 49:795-803. [PMID: 12880660 DOI: 10.1016/s0022-1910(03)00118-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Interactions between the locust endocrine and immune systems have been studied in vivo in relation to nodule formation and activation of the prophenoloxidase cascade in the haemolymph. Injection of bacterial lipopolysaccharide (LPS) extracted from Escherichia coli induces nodule formation in larval and adult locusts but does not increase phenoloxidase activity in the haemolymph. Nodule formation starts rapidly after injection of LPS and is virtually complete within 8 h, nodules occurring mainly associated with the dorsal diaphragm on either side of the heart, but sometimes with smaller numbers associated with the ventral diaphragm on either side of the nerve cord. Co-injection of adipokinetic hormone-I (Lom-AKH-I) with LPS stimulates greater numbers of nodules to be formed in larval and adult locusts, and activates phenoloxidase in the haemolymph of mature adults but not of nymphs. The effect of co-injection of Lom-AKH-I with LPS on nodule formation is seen at low doses of hormone; only 0.4 pmol of Lom-AKH-I per adult locust is needed to produce a 50% increase in the number of nodules formed. When different components of LPS from the E. coli Rd mutant are tested, the mono- and the diphosphoryl Lipid A components have similar effects to the intact LPS. Remarkably, detoxified LPS activates phenoloxidase in the absence of Lom-AKH-I, although co-injection with hormone does enhance this response. Both diphosphoryl Lipid A and detoxified LPS induce a level of nodule formation that is enhanced by co-injection of Lom-AKH-I, but monophosphoryl Lipid A does not initiate nodule formation even when injected with hormone. Co-injection of a water-soluble inhibitor of eicosanoid synthesis, diclofenac (2-[(2, 6-dichlorophenyl)amino] benzeneacetic acid), reduces nodule formation in response to injections of LPS (both in the absence and presence of hormone) in a dose-dependent manner, but does not prevent activation of phenoloxidase in adult locusts. It is shown that nodule formation and activation of the prophenoloxidase in locust haemolymph can both be enhanced by Lom-AKH-I, but it is argued that these processes involve distinct mechanisms in which eicosanoid synthesis is important for nodule formation, but not for the increased phenoloxidase activity.
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Affiliation(s)
- Graham Goldsworthy
- Department of Biology, Birkbeck College, University of London, Malet Street, London WC1E 7HX, UK.
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Bundey S, Raymond S, Dean P, Roberts SK, Dillon RJ, Charnley AK. Eicosanoid involvement in the regulation of behavioral fever in the desert locust, Schistocerca gregaria. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2003; 52:183-192. [PMID: 12655606 DOI: 10.1002/arch.10081] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The desert locust Schistocerca gregaria behaviorally thermoregulates in order to try and maintain a favoured "set point" body temperature. Locusts infected with the deuteromycete fungal pathogen Metarhizium anisopliae var acridumchoose a significantly elevated temperature. This "behavioral fever" greatly delays the progress of mycosis. We have confirmed this phenomenon and shown that desert locusts also fever when infected with the bacterial pathogen Serratia marcescens. Elevation in the prefered environmental temperature occurs also upon injection with laminarin and lipopolysaccharide (microbial cell wall components). Since such treatments also stimulate the immune system it would appear that "behavioral fever" is probably a feature of the immune response. The eicosanoid biosynthesis inhibitor dexamethasone prevented laminarin invoked fever. This effect was reversable by arachidonic acid. Therefore in common with the febrile response in mammals behavioral fever in insects may be mediated locally by circulating eicosanoids.
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Affiliation(s)
- S Bundey
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
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