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Perier JD, Kaplan F, Lewis EE, Alborn H, Schliekelman P, Toews MD, Schiller KC, Shapiro-Ilan DI. Enhancing entomopathogenic nematode efficacy with Pheromones: A field study targeting the pecan weevil. J Invertebr Pathol 2024; 203:108070. [PMID: 38311231 DOI: 10.1016/j.jip.2024.108070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/17/2024] [Accepted: 01/19/2024] [Indexed: 02/10/2024]
Abstract
Consistent efficacy is required for entomopathogenic nematodes to gain wider adoption as biocontrol agents. Recently, we demonstrated that when exposed to nematode pheromone blends, entomopathogenic nematodes showed increased dispersal, infectivity, and efficacy under laboratory and greenhouse conditions. Prior to this study, the impact of entomopathogenic nematode-pheromone combinations on field efficacy had yet to be studied. Steinernema feltiae is a commercially available entomopathogenic nematode that has been shown to increase mortality in insect pests such as the pecan weevil Curculio caryae. In this study, the pecan weevil was used as a model system to evaluate changes in S. feltiae efficacy when treated with a partially purified ascaroside pheromone blend. Following exposure to the pheromone blend, the efficacy of S. feltiae significantly increased as measured with decreased C. caryae survival despite unfavorable environmental conditions. The results of this study highlight a potential new avenue for using entomopathogenic nematodes in field conditions. With increased efficacy, using entomopathogenic nematodes will reduce reliance on conventional management methods in pecan production, translating into more environmentally acceptable practices.
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Affiliation(s)
- Jermaine D Perier
- Department of Entomology, University of Georgia, Tifton, GA 31793, United States
| | - Fatma Kaplan
- Pheronym, Inc., Woodland, CA 95695, United States
| | - Edwin E Lewis
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83844, United States
| | - Hans Alborn
- USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL 32608, United States
| | - Paul Schliekelman
- Department of Statistics, University of Georgia, Athens, GA 30602, United States
| | - Michael D Toews
- Department of Entomology, University of Georgia, Tifton, GA 31793, United States
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Stevens G, Usman M, Gulzar S, Stevens C, Pimentel E, Erdogan H, Schliekelman P, Kaplan F, Alborn H, Wakil W, Shapiro-Ilan D, Lewis EE. Group Movement in Entomopathogenic Nematodes: Aggregation Levels Vary Based on Context. J Nematol 2024; 56:20240002. [PMID: 38495935 PMCID: PMC10940270 DOI: 10.2478/jofnem-2024-0002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2024] [Indexed: 03/19/2024] Open
Abstract
Maintenance of an aggregated population structure implies within-species communication. In mixed-species environments, species-specific aggregations may reduce interspecific competition and promote coexistence. We studied whether movement and aggregation behavior of three entomopathogenic nematode species changed when isolated, as compared to mixed-species arenas. Movement and aggregation of Steinernema carpocapsae, S. feltiae and S. glaseri were assessed in sand. Each species demonstrated significant aggregation when alone. Mixed-species trials involved adding two species of nematodes, either combined in the center of the arena or at separate corners. While individual species became less aggregated than in single-species conditions when co-applied in the same location, they became more aggregated when applied in separate corners. This increased aggregation in separate-corner trials occurred even though the nematodes moved just as far when mixed together as they did when alone. These findings suggest that maintenance of multiple species within the same habitat is driven, at least in part, by species-specific signals that promote conspecific aggregation, and when the species are mixed (as occurs in some commercial formulations involving multiple EPN species), these signaling mechanisms are muddled.
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Affiliation(s)
- Glen Stevens
- University of Idaho, Department of Entomology, Plant Pathology and Nematology, Moscow, ID83844, USA
| | - Muhammad Usman
- Department of Entomology, University of Agriculture Faisalabad38000, Pakistan
| | - Sehrish Gulzar
- Department of Entomology, University of Agriculture Faisalabad38000, Pakistan
| | - Cassandra Stevens
- University of Idaho, Department of Entomology, Plant Pathology and Nematology, Moscow, ID83844, USA
| | - Eleanor Pimentel
- University of Idaho, Department of Entomology, Plant Pathology and Nematology, Moscow, ID83844, USA
| | - Hilal Erdogan
- University of Idaho, Department of Entomology, Plant Pathology and Nematology, Moscow, ID83844, USA
- Faculty of Agriculture, Department of Biosystems Engineering, Bursa Uludağ University, Bursa16059, Turkey
| | - Paul Schliekelman
- University of Georgia, Department of Statistics, Athens, GA30602, USA
| | | | - Hans Alborn
- Center for Medical, Agricultural, and Veterinary Entomology, U.S. Department of Agriculture Agricultural Research Service, 1700SW23rd Drive, Gainesville, FL, USA
| | - Waqas Wakil
- Department of Entomology, University of Agriculture Faisalabad38000, Pakistan
| | | | - Edwin E Lewis
- University of Idaho, Department of Entomology, Plant Pathology and Nematology, Moscow, ID83844, USA
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Coles TA, Briggs AM, Hambly MG, Céspedes N, Fellows AM, Kaylor HL, Adams AD, Van Susteren G, Bentil RE, Robert MA, Riffell JA, Lewis EE, Luckhart S. Ingested histamine and serotonin interact to alter Anopheles stephensi feeding and flight behavior and infection with Plasmodium parasites. Front Physiol 2023; 14:1247316. [PMID: 37555020 PMCID: PMC10405175 DOI: 10.3389/fphys.2023.1247316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 07/17/2023] [Indexed: 08/10/2023] Open
Abstract
Blood levels of histamine and serotonin (5-HT) are altered in human malaria, and, at these levels, we have shown they have broad, independent effects on Anopheles stephensi following ingestion by this invasive mosquito. Given that histamine and 5-HT are ingested together under natural conditions and that histaminergic and serotonergic signaling are networked in other organisms, we examined effects of combinations of these biogenic amines provisioned to A. stephensi at healthy human levels (high 5-HT, low histamine) or levels associated with severe malaria (low 5-HT, high histamine). Treatments were delivered in water (priming) before feeding A. stephensi on Plasmodium yoelii-infected mice or via artificial blood meal. Relative to effects of histamine and 5-HT alone, effects of biogenic amine combinations were complex. Biogenic amine treatments had the greatest impact on the first oviposition cycle, with high histamine moderating low 5-HT effects in combination. In contrast, clutch sizes were similar across combination and individual treatments. While high histamine alone increased uninfected A. stephensi weekly lifetime blood feeding, neither combination altered this tendency relative to controls. The tendency to re-feed 2 weeks after the first blood meal was altered by combination treatments, but this depended on mode of delivery. For blood delivery, malaria-associated treatments yielded higher percentages of fed females relative to healthy-associated treatments, but the converse was true for priming. Female mosquitoes treated with the malaria-associated combination exhibited enhanced flight behavior and object inspection relative to controls and healthy combination treatment. Mosquitoes primed with the malaria-associated combination exhibited higher mean oocysts and sporozoite infection prevalence relative to the healthy combination, with high histamine having a dominant effect on these patterns. Compared with uninfected A. stephensi, the tendency of infected mosquitoes to take a second blood meal revealed an interaction of biogenic amines with infection. We used a mathematical model to project the impacts of different levels of biogenic amines and associated changes on outbreaks in human populations. While not all outbreak parameters were impacted the same, the sum of effects suggests that histamine and 5-HT alter the likelihood of transmission by mosquitoes that feed on hosts with symptomatic malaria versus a healthy host.
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Affiliation(s)
- Taylor A. Coles
- Department of Entomology, Plant Pathology, and Nematology, University of Idaho, Moscow, ID, United States
| | - Anna M. Briggs
- Department of Entomology, Plant Pathology, and Nematology, University of Idaho, Moscow, ID, United States
| | - Malayna G. Hambly
- Department of Entomology, Plant Pathology, and Nematology, University of Idaho, Moscow, ID, United States
| | - Nora Céspedes
- Department of Entomology, Plant Pathology, and Nematology, University of Idaho, Moscow, ID, United States
| | - Abigail M. Fellows
- Department of Entomology, Plant Pathology, and Nematology, University of Idaho, Moscow, ID, United States
| | - Hannah L. Kaylor
- Department of Entomology, Plant Pathology, and Nematology, University of Idaho, Moscow, ID, United States
| | - Alexandria D. Adams
- Department of Entomology, Plant Pathology, and Nematology, University of Idaho, Moscow, ID, United States
| | - Grace Van Susteren
- Department of Biology, University of Washington, Seattle, WA, United States
| | - Ronald E. Bentil
- Department of Entomology, Plant Pathology, and Nematology, University of Idaho, Moscow, ID, United States
| | - Michael A. Robert
- Department of Mathematics, Center for Emerging, Zoonotic, and Arthropod-Borne Pathogens (CeZAP), Virginia Tech, Blacksburg, VA, United States
| | - Jeffrey A. Riffell
- Department of Biology, University of Washington, Seattle, WA, United States
| | - Edwin E. Lewis
- Department of Entomology, Plant Pathology, and Nematology, University of Idaho, Moscow, ID, United States
| | - Shirley Luckhart
- Department of Entomology, Plant Pathology, and Nematology, University of Idaho, Moscow, ID, United States
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
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Briggs AM, Hambly MG, Simão-Gurge RM, Garrison SM, Khaku Z, Van Susteren G, Lewis EE, Riffell JA, Luckhart S. Anopheles stephensi Feeding, Flight Behavior, and Infection With Malaria Parasites are Altered by Ingestion of Serotonin. Front Physiol 2022; 13:911097. [PMID: 35747317 PMCID: PMC9209645 DOI: 10.3389/fphys.2022.911097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/09/2022] [Indexed: 12/05/2022] Open
Abstract
Approximately 3.4 billion people are at risk of malaria, a disease caused by infection with Plasmodium spp. parasites, which are transmitted by Anopheles mosquitoes. Individuals with severe falciparum malaria often exhibit changes in circulating blood levels of biogenic amines, including reduced serotonin or 5-hydroxytryptamine (5-HT), and these changes are associated with disease pathology. In insects, 5-HT functions as an important neurotransmitter for many behaviors and biological functions. In Anopheles stephensi, we show that 5-HT is localized to innervation in the head, thorax, and midgut, suggesting a gut-to-brain signaling axis that could support the effects of ingested 5-HT on mosquito biology and behavioral responses. Given the changes in blood levels of 5-HT associated with severe malaria and the key roles that 5-HT plays in insect neurophysiology, we investigated the impact of ingesting blood with healthy levels of 5-HT (1.5 µM) or malaria-associated levels of 5-HT (0.15 µM) on various aspects of A. stephensi biology. In these studies, we provisioned 5-HT and monitored fecundity, lifespan, flight behavior, and blood feeding of A. stephensi. We also assessed the impact of 5-HT ingestion on infection of A. stephensi with the mouse malaria parasite Plasmodium yoelii yoelii 17XNL and the human malaria parasite Plasmodium falciparum. Our data show that ingestion of 5-HT associated with severe malaria increased mosquito flight velocity and investigation of visual objects in response to host odor (CO2). 5-HT ingestion in blood at levels associated with severe malaria also increased the tendency to take a second blood meal 4 days later in uninfected A. stephensi. In mosquitoes infected with P. y. yoelii 17XNL, feeding tendency was decreased when midgut oocysts were present but increased when sporozoites were present. In addition to these effects, treatment of A. stephensi with 5-HT associated with severe malaria increased infection success with P. y. yoelii 17XNL compared to control, while treatment with healthy levels of 5-HT decreased infection success with P. falciparum. These changes in mosquito behavior and infection success could be used as a basis to manipulate 5-HT signaling in vector mosquitoes for improved control of malaria parasite transmission.
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Affiliation(s)
- Anna M. Briggs
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Malayna G. Hambly
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Raquel M. Simão-Gurge
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Sarah M. Garrison
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Zainab Khaku
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Grace Van Susteren
- Department of Biology, University of Washington, Seattle, WA, United States
| | - Edwin E. Lewis
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Jeffrey A. Riffell
- Department of Biology, University of Washington, Seattle, WA, United States
| | - Shirley Luckhart
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
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Nikoukar A, Ensafi P, Lewis EE, Crowder DW, Rashed A. Efficacy of Naturally Occurring and Commercial Entomopathogenic Nematodes Against Sugar Beet Wireworm (Coleoptera: Elateridae). J Econ Entomol 2021; 114:2241-2244. [PMID: 34240170 DOI: 10.1093/jee/toab140] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Indexed: 06/13/2023]
Abstract
Wireworms are the larval stage of click beetles (Coleoptera: Elateridae), and some of their species are serious pests of many crops. In the present study, we evaluated the efficacy of naturally occurring and commercial entomopathogenic nematode species against the sugar beet wireworm, Limonius californicus (Mannerheim), in the laboratory. First, efficacies of Steinernema feltiae (Filipjev) (Rhabditida: Steinernematidae) collected from an irrigated (S. feltiae-SSK) and a dryland (S. feltiae-SSC) field and the two commercial entomopathogenic nematode species, S. carpocapsae (Weiser) (Rhabditida: Steinernematidae) and Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), were examined. Efficacies of the two field-collected S. feltiae isolates were also compared against a commercial S. feltiae strain. In the first bioassay, S. feltiae-SSK caused 63.3% wireworm mortality, followed by 30% caused by S. carpocapsae, 23.3% by S. feltiae-SSC, and 6.7% by H.bacteriophora. In the second assay, S. feltiae-SSK killed 56.7% of the wireworms, ≈2.1- and ≈5.7-fold higher than S. feltiae-SSC and the commercial isolate, respectively.
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Affiliation(s)
- Atoosa Nikoukar
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, 875 Perimeter Drive, MS 2329, Moscow, ID, USA
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Aberdeen Research and Extension Center, Aberdeen, ID, USA
| | - Pooria Ensafi
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Aberdeen Research and Extension Center, Aberdeen, ID, USA
| | - Edwin E Lewis
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, 875 Perimeter Drive, MS 2329, Moscow, ID, USA
| | - David W Crowder
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - Arash Rashed
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, 875 Perimeter Drive, MS 2329, Moscow, ID, USA
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Aberdeen Research and Extension Center, Aberdeen, ID, USA
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Rodriguez AM, Hambly MG, Jandu S, Simão-Gurge R, Lowder C, Lewis EE, Riffell JA, Luckhart S. Histamine Ingestion by Anopheles stephensi Alters Important Vector Transmission Behaviors and Infection Success with Diverse Plasmodium Species. Biomolecules 2021; 11:719. [PMID: 34064869 PMCID: PMC8151525 DOI: 10.3390/biom11050719] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 04/28/2021] [Accepted: 05/05/2021] [Indexed: 12/20/2022] Open
Abstract
An estimated 229 million people worldwide were impacted by malaria in 2019. The vectors of malaria parasites (Plasmodium spp.) are Anopheles mosquitoes, making their behavior, infection success, and ultimately transmission of great importance. Individuals with severe malaria can exhibit significantly increased blood concentrations of histamine, an allergic mediator in humans and an important insect neuromodulator, potentially delivered to mosquitoes during blood-feeding. To determine whether ingested histamine could alter Anopheles stephensi biology, we provisioned histamine at normal blood levels and at levels consistent with severe malaria and monitored blood-feeding behavior, flight activity, antennal and retinal responses to host stimuli and lifespan of adult female Anopheles stephensi. To determine the effects of ingested histamine on parasite infection success, we quantified midgut oocysts and salivary gland sporozoites in mosquitoes infected with Plasmodium yoelii and Plasmodium falciparum. Our data show that provisioning An. stephensi with histamine at levels consistent with severe malaria can enhance mosquito behaviors and parasite infection success in a manner that would be expected to amplify parasite transmission to and from human hosts. Such knowledge could be used to connect clinical interventions by reducing elevated histamine to mitigate human disease pathology with the delivery of novel lures for improved malaria control.
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Affiliation(s)
- Anna M. Rodriguez
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Malayna G. Hambly
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Sandeep Jandu
- Department of Biology, University of Washington, Seattle, WA 98195-1800, USA; (S.J.); (J.A.R.)
| | - Raquel Simão-Gurge
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Casey Lowder
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Edwin E. Lewis
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Jeffrey A. Riffell
- Department of Biology, University of Washington, Seattle, WA 98195-1800, USA; (S.J.); (J.A.R.)
| | - Shirley Luckhart
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
- Department of Biological Sciences, University of Idaho, Moscow, ID 83843-3051, USA
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Li C, Zhou X, Lewis EE, Yu Y, Wang C. Study on host-seeking behavior and chemotaxis of entomopathogenic nematodes using Pluronic F-127 gel. J Invertebr Pathol 2019; 161:54-60. [PMID: 30707919 DOI: 10.1016/j.jip.2019.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 12/31/2018] [Accepted: 01/26/2019] [Indexed: 10/27/2022]
Abstract
Pluronic F-127 gel (PF127) has proven to be a powerful medium in which to study host-finding behavior and chemotaxis for plant-parasitic nematodes. Pluronic gel can also be used to study host-habitat seeking behavior of entomopathogenic nematodes (EPN), which are natural enemies of root-feeding insect pests. In this study, PF127 was used to study tritrophic interactions among EPNs, host-habitat roots and insects. We also tested whether EPN aggregated to acetic acid (pH gradient) which mimicked the conditions near the roots. The chive root gnat Bradysia odoriphaga alone significantly attracted more nematodes than chive roots alone or the combination of roots plus insects. The attractiveness of B. odoriphaga differed (3.7-15.4%) among all tested species/strains of EPNs. In addition, we found that Heterorhabditis spp. and Steinernema spp. infective juveniles responded to pH gradients formed by acetic acid in Pluronic gel. The preferred pH ranges for strains of H. bacteriophora and H. megidis were from 4.32-5.04, and from 5.37-6.92 for Steinernema species, indicating that Heterorhabditis spp. prefer low pH conditions than Steinernema species. A narrow pH gradient between 6.84 and 7.05 was detected around chive root tips in which EPN was attracted. These results suggest that Pluronic gel can be broadly used for the study of host or host-habitat seeking behaviors and chemotaxis of nematodes.
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Affiliation(s)
- Chunjie Li
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China
| | - Xianhong Zhou
- Shandong Key Laboratory of Plant Virology, Institute of Plant Protection, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Edwin E Lewis
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83844, USA
| | - Yi Yu
- Shandong Key Laboratory of Plant Virology, Institute of Plant Protection, Shandong Academy of Agricultural Sciences, Jinan 250100, China.
| | - Congli Wang
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, China.
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Shapiro-Ilan DI, Kaplan F, Oliveira-Hofman C, Schliekelman P, Alborn HT, Lewis EE. Conspecific pheromone extracts enhance entomopathogenic infectivity. J Nematol 2019. [DOI: 10.21307/jofnem-2019-082] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Ruan WB, Shapiro-Ilan D, Lewis EE, Kaplan F, Alborn H, Gu XH, Schliekelman P. Movement patterns in Entomopathogenic nematodes: Continuous vs. temporal. J Invertebr Pathol 2017; 151:137-143. [PMID: 29158014 DOI: 10.1016/j.jip.2017.11.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 11/10/2017] [Accepted: 11/16/2017] [Indexed: 12/18/2022]
Abstract
To exploit resources, animals implement various foraging behaviors to increase their fitness. Entomopathogenic nematodes are obligate parasites of insects in nature. In previous studies, entomopathogenic nematodes were reported to exhibit group movement behavior in the presence and absence of insect hosts. However, it was not determined if group movement is continuous or temporal. For example, nematode movement behavior upon emergence from the host might start out in an independent fashion prior to aggregation, or group movement may be exhibited continuously. In the present study, we explored the propensity for innate group movement behavior of two insect parasitic nematodes in two families and genera: Heterorhabditis indica and Steinernema carpocapsae. We hypothesized the nematode populations would initially move independently from their origin and then come together for group movement. Movement patterns were investigated in sand when nematodes were applied in aqueous suspension (via filter paper) to a specific locus or when the nematodes emerged naturally from infected insect hosts. To compare nematode movement behavior over time and space, nematode dispersal was monitored at three distances (2.5, 4.5 and 8.0 cm) from the center (origin) and at two different time periods, 2 days and 3 days after nematode addition. We discovered that nematode dispersal continuously exhibited an aggregative pattern (independent movement was not observed). Results from both nematode species as well as the host-cadaver and filter paper (aqueous nematode suspension) application methods indicated a continuous aggregative pattern. The discovery of continuous aggregative movement patterns in steinernematid and heterorhabditid nematodes elucidates further the complexity of their foraging behavior and may serve as basis for exploring foraging behavior in other host-parasite systems.
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Affiliation(s)
- Wei-Bin Ruan
- College of Life Sciences, Nankai University, Tianjin 30071, China
| | | | - Edwin E Lewis
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83844, USA
| | | | - Hans Alborn
- USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL 32608, USA
| | - Xin-Hui Gu
- Yuxi Tobacco Company, Yuxi 653100, Yunnan, China
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Li X, Liu Q, Lewis EE, Tarasco E. Activity changes of antioxidant and detoxifying enzymes in Tenebrio molitor (Coleoptera: Tenebrionidae) larvae infected by the entomopathogenic nematode Heterorhabditis beicherriana (Rhabditida: Heterorhabditidae). Parasitol Res 2016; 115:4485-4494. [PMID: 27637224 DOI: 10.1007/s00436-016-5235-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 08/24/2016] [Indexed: 11/26/2022]
Abstract
Entomopathogenic nematodes (EPNs) of the genera Steinernema and Heterorhabditis are lethal parasites of many insect species. To investigate defensive mechanisms towards EPNs in relation to antioxidative and detoxifying enzymes, we chose Tenebrio molitor (Coleoptera: Tenebrionidae) as experimental insect. We studied the activity changes of superoxide dismutases (SODs), peroxidases (PODs), and catalases (CATs), as well as tyrosinase (TYR), acetylcholinesterase (AChE), carboxylesterase (CarE), and glutathione S-transferase (GSTs) for 40 h in T. molitor larvae infected with Heterorhabditis beicherriana infective juveniles (IJs) at 5 rates (0, 20, 40, 80, and 160 IJs/larva). We found that when T. molitor larvae infected with H. beicherriana at higher rates (80 and 160 IJs/larva), SOD activity quickly increased to more than 70 % higher than that control levels. The activities of POD and CAT increased after 24 h. TYR activity increased slowly at lower rates of infection for 16 h, followed by a slight decrease, and then increasing from 32 to 40 h. The other detoxifying enzymes (GST, CarE, and AChE) were enhanced at lower infection rates, but were inhibited at higher rates. Our results suggested that host antioxidative response and detoxification reactions played a central role in the defensive reaction to EPNs, and that this stress which was reflected by the higher level enzymes activity contributed to the death of hosts. Further study should explore the exact function of these enzymes using different species of EPNs and investigate the links between enzyme activity and host susceptibility to EPNs.
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Affiliation(s)
- Xingyue Li
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing, 100193, China
- Institute of Plant Protection, Sichuan Academy of Agricultural Science, Chengdu, 610066, China
| | - Qizhi Liu
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing, 100193, China.
| | - Edwin E Lewis
- Department of Entomology and Nematology, University of California-Davis, Davis, 95616, CA, USA
| | - Eustachio Tarasco
- Department of Soil, Plant and Food Science, University of Bari "Aldo Moro", Bari, 70126, Italy
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11
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Papadopoulos NT, Carey JR, Ioannou CS, Ji H, Müller HG, Wang JL, Luckhart S, Lewis EE. Seasonality of Post-capture Longevity in a Medically-Important Mosquito (Culex pipiens). Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00063] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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12
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Kepenekci I, Hazir S, Lewis EE. Evaluation of entomopathogenic nematodes and the supernatants of the in vitro culture medium of their mutualistic bacteria for the control of the root-knot nematodes Meloidogyne incognita and M. arenaria. Pest Manag Sci 2016; 72:327-34. [PMID: 25721911 DOI: 10.1002/ps.3998] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 02/22/2015] [Accepted: 02/23/2015] [Indexed: 05/13/2023]
Abstract
BACKGROUND The suppressive effects of various formulations of four entomopathogenic nematode (EPN) species and the supernatants of their mutualistic bacteria on the root-knot nematodes (RKNs) Meloidogyne incognita and M. arenaria in tomato roots were evaluated. The EPNs Steinernema carpocapsae, S. feltiae, S. glaseri and Heterorhabditis bacteriophora were applied as either live infective juveniles (IJs) or infected insect cadavers. Spent medium from culturing the bacterial symbionts Xenorhabdus bovienii and Photorhabdus luminescens kayaii with the cells removed was also applied without their nematode partners. RESULTS The aqueous suspensions of IJs, infected cadaver applications of EPNs and especially treatments of X. bovienii supernatant suppressed the negative impact of RKNs on tomatoes. Specific responses to treatment were reduced RKN egg masses, increased plant height and increased fresh and dry weights compared with the control where only RKNs were applied. CONCLUSION Among the treatments tested, the plant-dipping method of X. bovienii into bacterial culture fluid may be the most practical and effective method for M. incognita and M. arenaria control.
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Affiliation(s)
- Ilker Kepenekci
- Department of Plant Protection, Faculty of Agriculture, Gaziosmanpasa University, Tokat, Turkey
| | - Selcuk Hazir
- Department of Biology, Faculty of Arts and Sciences, Adnan Menderes University, Aydın, Turkey
| | - Edwin E Lewis
- Department of Entomology and Nematology, University of California, One Shields Ave., Davis, CA, USA
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13
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Dillman AR, Macchietto M, Porter CF, Rogers A, Williams B, Antoshechkin I, Lee MM, Goodwin Z, Lu X, Lewis EE, Goodrich-Blair H, Stock SP, Adams BJ, Sternberg PW, Mortazavi A. Comparative genomics of Steinernema reveals deeply conserved gene regulatory networks. Genome Biol 2015; 16:200. [PMID: 26392177 PMCID: PMC4578762 DOI: 10.1186/s13059-015-0746-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/10/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Parasitism is a major ecological niche for a variety of nematodes. Multiple nematode lineages have specialized as pathogens, including deadly parasites of insects that are used in biological control. We have sequenced and analyzed the draft genomes and transcriptomes of the entomopathogenic nematode Steinernema carpocapsae and four congeners (S. scapterisci, S. monticolum, S. feltiae, and S. glaseri). RESULTS We used these genomes to establish phylogenetic relationships, explore gene conservation across species, and identify genes uniquely expanded in insect parasites. Protein domain analysis in Steinernema revealed a striking expansion of numerous putative parasitism genes, including certain protease and protease inhibitor families, as well as fatty acid- and retinol-binding proteins. Stage-specific gene expression of some of these expanded families further supports the notion that they are involved in insect parasitism by Steinernema. We show that sets of novel conserved non-coding regulatory motifs are associated with orthologous genes in Steinernema and Caenorhabditis. CONCLUSIONS We have identified a set of expanded gene families that are likely to be involved in parasitism. We have also identified a set of non-coding motifs associated with groups of orthologous genes in Steinernema and Caenorhabditis involved in neurogenesis and embryonic development that are likely part of conserved protein-DNA relationships shared between these two genera.
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Affiliation(s)
- Adler R Dillman
- Department of Nematology, University of California, Riverside, CA, 92521, USA.
| | - Marissa Macchietto
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA.
| | - Camille F Porter
- Department of Biology and Evolutionary Ecology Laboratories, Brigham Young University, Provo, UT, 84602, USA.
| | - Alicia Rogers
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
| | - Brian Williams
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
| | - Igor Antoshechkin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
| | - Ming-Min Lee
- Department of Entomology, University of Arizona, Tucson, AZ, 85721, USA.
| | - Zane Goodwin
- Division of Biology and Biomedical Sciences, Washington University, St Louis, MO, 63110, USA.
| | - Xiaojun Lu
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, USA.
| | - Edwin E Lewis
- Department of Entomology and Nematology, University of California, Davis, CA, 95616, USA.
| | - Heidi Goodrich-Blair
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, USA.
| | - S Patricia Stock
- Department of Entomology, University of Arizona, Tucson, AZ, 85721, USA.
| | - Byron J Adams
- Department of Biology and Evolutionary Ecology Laboratories, Brigham Young University, Provo, UT, 84602, USA.
| | - Paul W Sternberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
- Howard Hughes Medical Institute, Pasadena, CA, 91125, USA.
| | - Ali Mortazavi
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA.
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14
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Wang B, Pakpour N, Napoli E, Drexler A, Glennon EKK, Surachetpong W, Cheung K, Aguirre A, Klyver JM, Lewis EE, Eigenheer R, Phinney BS, Giulivi C, Luckhart S. Anopheles stephensi p38 MAPK signaling regulates innate immunity and bioenergetics during Plasmodium falciparum infection. Parasit Vectors 2015; 8:424. [PMID: 26283222 PMCID: PMC4539710 DOI: 10.1186/s13071-015-1016-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 07/21/2015] [Indexed: 01/30/2023] Open
Abstract
Background Fruit flies and mammals protect themselves against infection by mounting immune and metabolic responses that must be balanced against the metabolic needs of the pathogens. In this context, p38 mitogen-activated protein kinase (MAPK)-dependent signaling is critical to regulating both innate immunity and metabolism during infection. Accordingly, we asked to what extent the Asian malaria mosquito Anopheles stephensi utilizes p38 MAPK signaling during infection with the human malaria parasite Plasmodium falciparum. Methods A. stephensi p38 MAPK (AsP38 MAPK) was identified and patterns of signaling in vitro and in vivo (midgut) were analyzed using phospho-specific antibodies and small molecule inhibitors. Functional effects of AsP38 MAPK inhibition were assessed using P. falciparum infection, quantitative real-time PCR, assays for reactive oxygen species and survivorship under oxidative stress, proteomics, and biochemical analyses. Results The genome of A. stephensi encodes a single p38 MAPK that is activated in the midgut in response to parasite infection. Inhibition of AsP38 MAPK signaling significantly reduced P. falciparum sporogonic development. This phenotype was associated with AsP38 MAPK regulation of mitochondrial physiology and stress responses in the midgut epithelium, a tissue critical for parasite development. Specifically, inhibition of AsP38 MAPK resulted in reduction in mosquito protein synthesis machinery, a shift in glucose metabolism, reduced mitochondrial metabolism, enhanced production of mitochondrial reactive oxygen species, induction of an array of anti-parasite effector genes, and decreased resistance to oxidative stress-mediated damage. Hence, P. falciparum-induced activation of AsP38 MAPK in the midgut facilitates parasite infection through a combination of reduced anti-parasite immune defenses and enhanced host protein synthesis and bioenergetics to minimize the impact of infection on the host and to maximize parasite survival, and ultimately, transmission. Conclusions These observations suggest that, as in mammals, innate immunity and mitochondrial responses are integrated in mosquitoes and that AsP38 MAPK-dependent signaling facilitates mosquito survival during parasite infection, a fact that may attest to the relatively longer evolutionary relationship of these parasites with their invertebrate compared to their vertebrate hosts. On a practical level, improved understanding of the balances and trade-offs between resistance and metabolism could be leveraged to generate fit, resistant mosquitoes for malaria control. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-1016-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bo Wang
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, 3437 Tupper Hall, One Shields Avenue, Davis, CA, 95616, USA.
| | - Nazzy Pakpour
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, 3437 Tupper Hall, One Shields Avenue, Davis, CA, 95616, USA.
| | - Eleonora Napoli
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA.
| | - Anna Drexler
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, 3437 Tupper Hall, One Shields Avenue, Davis, CA, 95616, USA.
| | - Elizabeth K K Glennon
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, 3437 Tupper Hall, One Shields Avenue, Davis, CA, 95616, USA.
| | - Win Surachetpong
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, 3437 Tupper Hall, One Shields Avenue, Davis, CA, 95616, USA.
| | - Kong Cheung
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, 3437 Tupper Hall, One Shields Avenue, Davis, CA, 95616, USA.
| | - Alejandro Aguirre
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, 3437 Tupper Hall, One Shields Avenue, Davis, CA, 95616, USA.
| | - John M Klyver
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, 3437 Tupper Hall, One Shields Avenue, Davis, CA, 95616, USA.
| | - Edwin E Lewis
- Department of Entomology and Nematology, University of California Davis, Davis, CA, USA.
| | - Richard Eigenheer
- Genome and Biomedical Sciences Center, University of California Davis, Davis, CA, USA.
| | - Brett S Phinney
- Genome and Biomedical Sciences Center, University of California Davis, Davis, CA, USA.
| | - Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA. .,Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, Davis, CA, USA.
| | - Shirley Luckhart
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, 3437 Tupper Hall, One Shields Avenue, Davis, CA, 95616, USA.
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15
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Cator LJ, Pietri JE, Murdock CC, Ohm JR, Lewis EE, Read AF, Luckhart S, Thomas MB. Immune response and insulin signalling alter mosquito feeding behaviour to enhance malaria transmission potential. Sci Rep 2015; 5:11947. [PMID: 26153094 PMCID: PMC4495552 DOI: 10.1038/srep11947] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 06/04/2015] [Indexed: 12/18/2022] Open
Abstract
Malaria parasites alter mosquito feeding behaviour in a way that enhances parasite transmission. This is widely considered a prime example of manipulation of host behaviour to increase onward transmission, but transient immune challenge in the absence of parasites can induce the same behavioural phenotype. Here, we show that alterations in feeding behaviour depend on the timing and dose of immune challenge relative to blood ingestion and that these changes are functionally linked to changes in insulin signalling in the mosquito gut. These results suggest that altered phenotypes derive from insulin signalling-dependent host resource allocation among immunity, blood feeding, and reproduction in a manner that is not specific to malaria parasite infection. We measured large increases in mosquito survival and subsequent transmission potential when feeding patterns are altered. Leveraging these changes in physiology, behaviour and life history could promote effective and sustainable control of female mosquitoes responsible for transmission.
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Affiliation(s)
- Lauren J Cator
- Grand Challenges in Ecosystem and Environment, Department of Life Sciences, Imperial College London, Silwood Park
| | - Jose E Pietri
- Department of Medical Microbiology and Immunology, University of California, Davis
| | - Courtney C Murdock
- Department of Infectious Disease in College of Veterinary Medicine and Odum School of Ecology, University of Georgia
| | - Johanna R Ohm
- Center for Infectious Disease Dynamics, Pennsylvania State University
| | - Edwin E Lewis
- Department of Entomology, University of California, Davis
| | - Andrew F Read
- Center for Infectious Disease Dynamics, Pennsylvania State University
| | - Shirley Luckhart
- Department of Medical Microbiology and Immunology, University of California, Davis
| | - Matthew B Thomas
- Center for Infectious Disease Dynamics, Pennsylvania State University
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16
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Shapiro-Ilan DI, Brown I, Lewis EE. Freezing and desiccation tolerance in entomopathogenic nematodes: diversity and correlation of traits. J Nematol 2014; 46:27-34. [PMID: 24643501 PMCID: PMC3957569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Indexed: 06/03/2023] Open
Abstract
The ability of entomopathogenic nematodes to tolerate environmental stress such as desiccating or freezing conditions, can contribute significantly to biocontrol efficacy. Thus, in selecting which nematode to use in a particular biocontrol program, it is important to be able to predict which strain or species to use in target areas where environmental stress is expected. Our objectives were to (i) compare inter- and intraspecific variation in freeze and desiccation tolerance among a broad array of entomopathogenic nematodes, and (ii) determine if freeze and desiccation tolerance are correlated. In laboratory studies we compared nematodes at two levels of relative humidity (RH) (97% and 85%) and exposure periods (24 and 48 h), and nematodes were exposed to freezing temperatures (-2°C) for 6 or 24 h. To assess interspecific variation, we compared ten species including seven that are of current or recent commercial interest: Heterorhabditis bacteriophora (VS), H. floridensis, H. georgiana, (Kesha), H. indica (HOM1), H. megidis (UK211), Steinernema carpocapsae (All), S. feltiae (SN), S. glaseri (VS), S. rarum (17C&E), and S. riobrave (355). To assess intraspecific variation we compared five strains of H. bacteriophora (Baine, Fl1-1, Hb, Oswego, and VS) and four strains of S. carpocapsae (All, Cxrd, DD136, and Sal), and S. riobrave (355, 38b, 7-12, and TP). S. carpocapsae exhibited the highest level of desiccation tolerance among species followed by S. feltiae and S. rarum; the heterorhabditid species exhibited the least desiccation tolerance and S. riobrave and S. glaseri were intermediate. No intraspecific variation was observed in desiccation tolerance; S. carpocapsae strains showed higher tolerance than all H. bacteriophora or S. riobrave strains yet there was no difference detected within species. In interspecies comparisons, poor freeze tolerance was observed in H. indica, and S. glaseri, S. rarum, and S. riobrave whereas H. georgiana and S. feltiae exhibited the highest freeze tolerance, particularly in the 24-h exposure period. Unlike desiccation tolerance, substantial intraspecies variation in freeze tolerance was observed among H. bacteriophora and S. riobrave strains, yet within species variation was not detected among S. carpocapsae strains. Correlation analysis did not detect a relationship between freezing and desiccation tolerance.
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Affiliation(s)
| | - Ian Brown
- Department of Biology, Georgia Southwestern University, Americus, GA
| | - Edwin E Lewis
- UC Davis, Department of Entomology and Nematology, University of California, Davis, CA 95616
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17
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Villamil SC, Lewis EE, Zalom FG. Seasonal pheromone trap catches of male Bactrocera oleae (Diptera: Tephritidae) in northern California: asynchrony with host (olive tree) phenology? Environ Entomol 2013; 42:1356-1362. [PMID: 24468560 DOI: 10.1603/en13093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Bactrocera oleae (Rossi) (Diptera: Tephritidae, Dacinae) is an oligophagous species that feeds only on cultivated olives (Olea europaea L.) and its close relatives. Synchrony of seasonal activity patterns of B. oleae, the olive fruit fly with its host's phenology is therefore expected. The objective of this study was to monitor the male olive fruit fly response to female sex pheromone in the field. White sticky traps were deployed year round for 3 yr in an olive orchard in Oroville, CA. They were checked periodically, and flies captured were counted and sexed. Although males were captured regularly, the numbers of females captured on pheromone traps were negligible. Food-baited traps and water-baited traps were deployed to show the presence of flies in the field. Our hypothesis that males would respond to pheromone when females were available and olive fruits were susceptible for oviposition was partially supported. There were two peaks of high male captures in pheromone traps: spring and fall. In spring, females were available and mature but few acceptable olives were available for oviposition (no new crop olives yet). In fall, females were present but many of the new crop olives were already infested. The food baited traps confirmed the presence of flies in the field even when very few were being captured in the pheromone-baited traps. Traps containing only water caught only two flies showing that water alone or the trap type in itself was not attractive to flies.
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Affiliation(s)
- Soledad C Villamil
- Department of Entomology and Nematology, University of California, One Shields Avenue, Davis, CA95616, USA
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18
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Nadler SA, Lyons ET, Pagan C, Hyman D, Lewis EE, Beckmen K, Bell CM, Castinel A, DeLong RL, Duignan PJ, Farinpour C, Huntington KB, Kuiken T, Morgades D, Naem S, Norman R, Parker C, Ramos P, Spraker TR, Berón-Vera B. Molecular systematics of pinniped hookworms (Nematoda: Uncinaria): species delimitation, host associations and host-induced morphometric variation. Int J Parasitol 2013; 43:1119-32. [DOI: 10.1016/j.ijpara.2013.08.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 08/28/2013] [Accepted: 08/31/2013] [Indexed: 10/26/2022]
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19
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Shapiro-Ilan DI, Lewis EE, Schliekelman P. Aggregative group behavior in insect parasitic nematode dispersal. Int J Parasitol 2013; 44:49-54. [PMID: 24184157 DOI: 10.1016/j.ijpara.2013.10.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 10/01/2013] [Accepted: 10/05/2013] [Indexed: 01/18/2023]
Abstract
Movement behavior of foraging animals is critical to the determination of their spatial ecology and success in exploiting resources. Individuals sometimes gain advantages by foraging in groups to increase their efficiency in garnering these resources. Group movement behavior has been studied in various vertebrates. In this study we explored the propensity for innate group movement behavior among insect parasitic nematodes. Given that entomopathogenic nematodes benefit from group attack and infection, we hypothesised that the populations would tend to move in aggregate in the absence of extrinsic cues. Movement patterns of entomopathogenic nematodes in sand were investigated when nematodes were applied to a specific locus or when the nematodes emerged naturally from infected insect hosts; six nematode species in two genera were tested (Heterorhabditis bacteriophora, Heterorhabditis indica, Steinernema carpocapsae, Steinernema feltiae, Steinernema glaseri and Steinernema riobrave). Nematodes were applied in aqueous suspension via filter paper discs or in infected insect host cadavers (to mimic emergence in nature). We discovered that nematode dispersal resulted in an aggregated pattern rather than a random or uniform distribution; the only exception was S. glaseri when emerging directly from infected hosts. The group movement may have been continuous from the point of origin, or it may have been triggered by a propensity to aggregate after a short period of random movement. To our knowledge, this is the first report of group movement behavior in parasitic nematodes in the absence of external stimuli (e.g., without an insect or other apparent biotic or abiotic cue). These findings have implications for nematode spatial distribution and suggest that group behavior is involved in nematode foraging.
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Affiliation(s)
| | - Edwin E Lewis
- University of California Davis, Department of Nematology and Entomology, University of California, Davis, CA 95616, USA
| | - Paul Schliekelman
- Department of Statistics, University of Georgia, Athens, GA 30602, USA.
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20
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Somers EC, Marder W, Cagnoli P, Lewis EE, DeGuire P, Gordon C, Helmick CG, Wang L, Wing JJ, Dhar JP, Liesen J, McCune WJ. 'MiLES' population-based survey of the incidence and prevalence of systemic lupus erythematosus in Southeastern Michigan. Arthritis Res Ther 2012. [PMCID: PMC3467525 DOI: 10.1186/ar3982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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21
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Nielsen AL, Lewis EE. Designing the ideal habitat for entomopathogen use in nursery production. Pest Manag Sci 2012; 68:1053-1061. [PMID: 22371424 DOI: 10.1002/ps.3267] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 11/30/2011] [Accepted: 01/09/2012] [Indexed: 05/31/2023]
Abstract
BACKGROUND Greenhouse and nursery producers use entomopathogens (nematodes and fungi) to control soil pests. Although it is known that the physical and chemical properties of mineral soil significantly impact upon soil pathogens, the influence of soilless media used for plant production on entomopathogen performance is poorly understood. RESULTS Survival and foraging distance were differently affected by sand:peat, bark and sawdust media for entomopathogenic nematodes, but not for the immobile fungus Metarhizium anisopliae. Redwood sawdust medium consistently had a negative impact upon entomopathogenic nematodes. Dividing media into individual components supported the hypothesis that redwood sawdust reduced foraging and infection abilities of S. riobrave and H. bacteriophora. Physically altering the components by adding sand significantly improved foraging and infection success for S. riobrave in media not optimum for foraging. CONCLUSION This study is the first to highlight the importance of selecting the appropriate soilless media and pathogen species combinations to increase efficacy of biological control. H. bacteriophora was able to find hosts in a wider diversity of medium components than S. riobrave, although both nematode species performed well in peat moss and recycled plant material. These results suggest that peat moss, recycled plant material and hardwood bark are components amenable to EPN biological control programs.
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Affiliation(s)
- Anne L Nielsen
- Department of Nematology, University of California, Davis, CA, USA.
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22
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Shapiro-Ilan DI, Lewis EE, Campbell JF, Kim-Shapiro DB. Directional movement of entomopathogenic nematodes in response to electrical field: effects of species, magnitude of voltage, and infective juvenile age. J Invertebr Pathol 2012; 109:34-40. [DOI: 10.1016/j.jip.2011.09.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 09/02/2011] [Accepted: 09/06/2011] [Indexed: 10/17/2022]
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24
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Hodson AK, Friedman ML, Wu LN, Lewis EE. European earwig (Forficula auricularia) as a novel host for the entomopathogenic nematode Steinernema carpocapsae. J Invertebr Pathol 2011; 107:60-4. [PMID: 21356215 DOI: 10.1016/j.jip.2011.02.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 02/17/2011] [Accepted: 02/20/2011] [Indexed: 11/19/2022]
Abstract
The natural history of many entomopathogenic nematode species remains unknown, despite their wide commercial availability as biological control agents. The ambushing entomopathogenic nematode, Steinernema carpocapsae, and the introduced European earwig, Forficula auricularia, forage on the soil surface. Since they likely encounter one another in nature, we hypothesized that earwigs are susceptible to nematode infection. In the laboratory, the LC(50) for F. auricularia was 226 S. carpocapsae/earwig and the reproductive potential was 123.5 infective juvenile nematodes/mg tissue. This susceptibility depended on host body size with significantly higher mortality rates seen in larger earwigs. In a study of host recognition behavior, S. carpocapsae infective juveniles responded to earwig cuticle as strongly as they did to Galleria mellonella cuticle. We also found that earwigs exposed to S. carpocapsae cleaned and scratched their front, middle and back legs significantly more than controls. Coupled with previous field data, these findings lead us to suggest that F. auricularia may be a potential host for S. carpocapsae.
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Affiliation(s)
- A K Hodson
- Department of Land, Air and Water Resources, University of California Davis, United States.
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25
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Abstract
Abstract
Soil salinity, measured as electroconductivity (dS m–1), is a
major problem in crop production, including areas where entomopathogenic
nematodes (EPN) are applied as biological control agents. EPN species,
primarily Heterorhabditis, have been isolated from coastal
areas and agricultural soils with high salinity (> 4.0
dS m–1). Given the aqueous nature of their environment, soil
salinity may play an important role in EPN movement and host finding. We
assessed the survival of Steinernema riobrave, S.
glaseri, Heterorhabditis indica, H.
sonorensis and H. bacteriophora exposed to
saline soils within the range found in agricultural soils. Survival and
infectivity were generally unaffected by salinities ranging from 0 to 50 dS
m–1 (50 dS m–1 is similar to the salinity of
seawater). Salinity had been shown to negatively impact foraging in
S. riobrave so additional experiments analysing the
behaviour and attraction to host cues by S. riobrave and
H. indica were conducted. Agar-based behavioural assays
revealed species-specific responses to salinity. At the higher salinity
levels (30 and 50 dS m–1) movement of H. indica
decreased, the path taken was more circuitous and individuals did not move
toward a host. There was a strong antagonistic effect on H.
indica motility and host-finding behaviour. No significant
differences were observed for S. riobrave exposed to any of
these salinity levels. However, under simulated field conditions, high
saline conditions (30 and 50 dS m–1) reduced the distance both
H. indica and S. riobrave travelled
toward a host. Both species are used for biological control of weevil pests
in orchards where salinities have been recorded up to 20 dS m–1.
Field efficacy of EPN applied for biological control in saline soils may be
improved by timing applications to avoid late season build-up of salts in
irrigated crops and applying the appropriate EPN species.
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Affiliation(s)
- Anne L. Nielsen
- 1University of California-Davis, Department of Nematology, Davis, CA 95616, USA;,
| | - Kenneth O. Spence
- 2University of California-Davis, Department of Nematology, Davis, CA 95616, USA
| | - Jamie Nakatani
- 3University of California-Davis, Department of Nematology, Davis, CA 95616, USA
| | - Edwin E. Lewis
- 4University of California-Davis, Department of Nematology, Davis, CA 95616, USA
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Noosidum A, Hodson AK, Lewis EE, Chandrapatya A. Characterization of New Entomopathogenic Nematodes from Thailand: Foraging Behavior and Virulence to the Greater Wax Moth, Galleria mellonella L. (Lepidoptera: Pyralidae). J Nematol 2010; 42:281-91. [PMID: 22736860 PMCID: PMC3380524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Indexed: 06/01/2023] Open
Abstract
Entomopathogenic nematodes (EPNs) in the genera Steinernema and Heterorhabditis and their associated bacteria (Xenorhabdus spp. and Photorhabdus spp., respectively) are lethal parasites of soil dwelling insects. We collected 168 soil samples from five provinces, all located in southern Thailand. Eight strains of EPNs were isolated and identified to species using restriction profiles and sequence analysis. Five of the isolates were identified as Heterorhabditis indica, and one as Heterorhabditis baujardi. Two undescribed Steinernema spp. were also discovered which matched no published sequences and grouped separately from the other DNA restriction profiles. Behavioral tests showed that all Heterorhabditis spp. were cruise foragers, based on their attraction to volatile cues and lack of body-waving and standing behaviors, while the Steinernema isolates were more intermediate in foraging behavior. The infectivity of Thai EPN strains against Galleria mellonella larvae was investigated using sand column bioassays and the LC(50) was calculated based on exposures to nematodes in 24-well plates. The LC(50) results ranged from 1.99-6.95 IJs/insect. Nine centimeter columns of either sandy loam or sandy clay loam were used to determine the nematodes' ability to locate and infect subterranean insects in different soil types. The undescribed Steinernema sp. had the greatest infection rate in both soil types compared to the other Thai isolates and three commercial EPNs (Heterorhabditis bacteriophora, Steinernema glaseri and Steinernema riobrave).
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Affiliation(s)
- Atirach Noosidum
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Chatuchak, Bangkok 10900, Thailand
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Corby-Harris V, Drexler A, Watkins de Jong L, Antonova Y, Pakpour N, Ziegler R, Ramberg F, Lewis EE, Brown JM, Luckhart S, Riehle MA. Correction: Activation of Akt signaling reduces the prevalence and intensity of malaria parasite infection and lifespan in Anopheles stephensi mosquitoes. PLoS Pathog 2010; 6. [PMID: 20714345 PMCID: PMC2919565 DOI: 10.1371/annotation/738ac91f-8c41-4bf5-9a39-bddf0b777a89] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Malaria (Plasmodium spp.) kills nearly one million people annually and this number will likely increase as drug and insecticide resistance reduces the effectiveness of current control strategies. The most important human malaria parasite, Plasmodium falciparum, undergoes a complex developmental cycle in the mosquito that takes approximately two weeks and begins with the invasion of the mosquito midgut. Here, we demonstrate that increased Akt signaling in the mosquito midgut disrupts parasite development and concurrently reduces the duration that mosquitoes are infective to humans. Specifically, we found that increased Akt signaling in the midgut of heterozygous Anopheles stephensi reduced the number of infected mosquitoes by 60-99%. Of those mosquitoes that were infected, we observed a 75-99% reduction in parasite load. In homozygous mosquitoes with increased Akt signaling parasite infection was completely blocked. The increase in midgut-specific Akt signaling also led to an 18-20% reduction in the average mosquito lifespan. Thus, activation of Akt signaling reduced the number of infected mosquitoes, the number of malaria parasites per infected mosquito, and the duration of mosquito infectivity.
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Affiliation(s)
- Vanessa Corby-Harris
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
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Corby-Harris V, Drexler A, Watkins de Jong L, Antonova Y, Pakpour N, Ziegler R, Ramberg F, Lewis EE, Brown JM, Luckhart S, Riehle MA. Activation of Akt signaling reduces the prevalence and intensity of malaria parasite infection and lifespan in Anopheles stephensi mosquitoes. PLoS Pathog 2010; 6:e1001003. [PMID: 20664791 PMCID: PMC2904800 DOI: 10.1371/journal.ppat.1001003] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 06/16/2010] [Indexed: 12/14/2022] Open
Abstract
Malaria (Plasmodium spp.) kills nearly one million people annually and this number will likely increase as drug and insecticide resistance reduces the effectiveness of current control strategies. The most important human malaria parasite, Plasmodium falciparum, undergoes a complex developmental cycle in the mosquito that takes approximately two weeks and begins with the invasion of the mosquito midgut. Here, we demonstrate that increased Akt signaling in the mosquito midgut disrupts parasite development and concurrently reduces the duration that mosquitoes are infective to humans. Specifically, we found that increased Akt signaling in the midgut of heterozygous Anopheles stephensi reduced the number of infected mosquitoes by 60-99%. Of those mosquitoes that were infected, we observed a 75-99% reduction in parasite load. In homozygous mosquitoes with increased Akt signaling parasite infection was completely blocked. The increase in midgut-specific Akt signaling also led to an 18-20% reduction in the average mosquito lifespan. Thus, activation of Akt signaling reduced the number of infected mosquitoes, the number of malaria parasites per infected mosquito, and the duration of mosquito infectivity.
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Affiliation(s)
- Vanessa Corby-Harris
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
| | - Anna Drexler
- Medical Microbiology and Immunology, University of California – Davis, Davis, California, United States of America
| | - Laurel Watkins de Jong
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
| | - Yevgeniya Antonova
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
| | - Nazzy Pakpour
- Medical Microbiology and Immunology, University of California – Davis, Davis, California, United States of America
| | - Rolf Ziegler
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
| | - Frank Ramberg
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
| | - Edwin E. Lewis
- Department of Entomology, University of California – Davis, Davis, California, United States of America
- Department of Nematology, University of California – Davis, Davis, California, United States of America
| | - Jessica M. Brown
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
| | - Shirley Luckhart
- Medical Microbiology and Immunology, University of California – Davis, Davis, California, United States of America
| | - Michael A. Riehle
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
- * E-mail:
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Marder W, Somers EC, Kaplan MJ, Anderson MR, Lewis EE, McCune WJ. Effects of prasterone (dehydroepiandrosterone) on markers of cardiovascular risk and bone turnover in premenopausal women with systemic lupus erythematosus: a pilot study. Lupus 2010; 19:1229-36. [PMID: 20530522 DOI: 10.1177/0961203310371156] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
DHEA (dehydroepiandrosterone) is a weak androgen with proposed efficacy in the treatment of mild to moderate lupus, and possible beneficial effects on cardiovascular risk and bone mineral density. We hypothesized that treatment with 200 mg a day of Prasterone (DHEA) would improve pre-clinical measures of atherosclerosis: flow-mediated dilatation (FMD), nitroglycerin-mediated dilatation (NMD), and circulating apoptotic endothelial cells (CD 146(AnnV +)), as well markers of bone metabolism. Thirteen premenopausal female patients with Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) <or=8 were enrolled in a double-blind placebo-controlled crossover trial for 22 weeks with a 6-week washout between treatment periods. Results reveal high-density lipoprotein (HDL) levels significantly decreased with Prasterone (48.5 versus 56.3 with placebo, p <or= 0.001), and there was a trend towards impairment of endothelial function with Prasterone (brachial artery FMD 3.4% versus 4.4% with placebo, mean difference -1.07, NMD 19.5% versus 24.4% with placebo, mean difference -4.9, p = NS). There were no differences between groups in SLEDAI, CD146( AnnV+) cells, or receptor activator for nuclear factor kB ligand (RANKL)/osteoprotegerin, although RANKL was higher after treatment with Prasterone (mean difference -29.5 units; p = 0.097). This pilot study does not support the use of Prasterone in mild lupus for prevention of atherosclerosis or osteoporosis, and confirms other findings of potentially harmful effects on lipids.
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Affiliation(s)
- W Marder
- University of Michigan Health System, Ann Arbor, MI, USA.
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Abstract
Abstract
Bionematicides may exhibit complex modes of action based on: i) direct lethal
or sub-lethal effects on the nematode; ii) promotion of plant growth and
damage tolerance; and/or iii) influencing the interaction between the plant
and the nematode by inducing plant defences. A suite of assays was conducted
to characterise the mode of action of the commercial bionematicide DiTera®
(Valent Biosciences, Chicago, IL, USA). Agar-based behavioural assays
revealed significant chemotactic responses of second-stage juveniles of
Meloidogyne incognita to DiTera with concentrations of 1.0% and 0.1% being
repellent and 0.01% being attractive to M. incognita. In addition, exposure
to 1.0% DiTera reduced the velocity and increased the meander of nematodes
in no-choice tests. These experiments were complemented with soil-based
assays. Rhizotron and minirhizotron assays that allowed spatially explicit
evaluation of root growth demonstrated root proliferation of Solanum
lycopersicum cv. Rutgers in response to localised applications of DiTera.
Our results confirm that DiTera can positively affect plant growth and may
influence nematode foraging behaviour. However, results of the soil-based
assays provided little support for the hypothesis that DiTera has direct or
indirect (plant-mediated) effects on M. incognita performance. This is in
contrast to some of the published literature, and it may be that the chosen
methods were not appropriate to detect these effects.
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Affiliation(s)
- Kenneth O. Spence
- 1Department of Nematology, University of California, Davis, CA 95616, USA;,
| | - Edwin E. Lewis
- 2Department of Nematology, University of California, Davis, CA 95616, USA
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Tiwari S, Youngman RR, Lewis EE, Eisenback JD. European corn borer (Lepidoptera: Crambidae) stalk tunneling on root-knot nematode (Tylenchida: Heteroderidae) fitness on corn. J Econ Entomol 2009; 102:602-609. [PMID: 19449640 DOI: 10.1603/029.102.0218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Greenhouse experiments were conducted in 2004-2006 to examine the reciprocal effects of aboveground herbivory by European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), and belowground herbivory by root-knot nematode, Meloidogyne incognita Chitwood (Tylenchida: Heteroderidae), on one another at three corn, Zea mays L., growth stages. Two experiments were conducted to study the effect of aboveground herbivory by O. nubilalis on the number of M. incognita juvenile penetration/root system and eggs/root system. In the first experiment, the O. nubilalis infestation level by plant growth stage main effect interaction was not significant for either M. incognita juvenile penetration or eggs. The overall effect of stalk tunneling by O. nubilalis resulted in 48.9% fewer juvenile penetration and 40.0% fewer eggs than in the respective controls. In the second experiment, the main effects interaction was significant for juvenile penetration (P = 0.0422) and eggs (P = 0.0134). At the eight- and 10-leaf growth stages, the combined effect of one and three O. nubilalis larvae per plant resulted in 41.2 and 44.7% significantly fewer juvenile penetration than in the respective controls. Similarly, the combined effect of stalk tunneling (with the exception of one larvae per plant at the 10-leaf growth stage) at the six-, eight-, and 10-leaf growth stages resulted in 46.3, 53.3, and 55.2% fewer eggs than in the respective controls. In all instances, M. incognita juvenile penetration and eggs were significantly negatively correlated with O. nubilalis tunnel length. In a reciprocal experiment conducted two times, no significant (P > 0.05) effect of M. incognita inoculation level on stalk tunneling was found in either experiment.
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Affiliation(s)
- S Tiwari
- Alson H. Smith, Jr. AREC, Winchester, VA 22602, USA.
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Fushing H, Zhu L, Shapiro-Ilan DI, Campbell JF, Lewis EE. STATE-SPACE BASED MASS EVENT-HISTORY MODEL I: MANY DECISION-MAKING AGENTS WITH ONE TARGET. Ann Appl Stat 2008; 2:1503-1522. [PMID: 19421335 DOI: 10.1214/08-aoas189] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A dynamic decision-making system that includes a mass of indistinguishable agents could manifest impressive heterogeneity. This kind of non-homogeneity is postulated to result from macroscopic behavioral tactics employed by almost all involved agents. A State-Space Based (SSB) mass event-history model is developed here to explore the potential existence of such macroscopic behaviors. By imposing an unobserved internal state-space variable into the system, each individual's event-history is made into a composition of a common state duration and an individual specific time to action. With the common state modeling of the macroscopic behavior, parametric statistical inferences are derived under the current-status data structure and conditional independence assumptions. Identifiability and computation related problems are also addressed. From the dynamic perspectives of system-wise heterogeneity, this SSB mass event-history model is shown to be very distinct from a random effect model via the Principle Component Analysis (PCA) in a numerical experiment. Real data showing the mass invasion by two species of parasitic nematode into two species of host larvae are also analyzed. The analysis results not only are found coherent in the context of the biology of the nematode as a parasite, but also include new quantitative interpretations.
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Affiliation(s)
- Hsieh Fushing
- Department of Statistics, University of California, Davis, California 95616, USA
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Christen JM, Campbell JF, Zurek L, Shapiro-Ilan DI, Lewis EE, Ramaswamy SB. Role of symbiotic and non-symbiotic bacteria in carbon dioxide production from hosts infected with Steinernema riobrave. J Invertebr Pathol 2008; 99:35-42. [PMID: 18621386 DOI: 10.1016/j.jip.2008.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Revised: 04/15/2008] [Accepted: 05/22/2008] [Indexed: 10/22/2022]
Abstract
Entomopathogenic nematodes of the family Steinernematidae and their mutualistic bacteria (Xenorhabdus spp.) are lethal endoparasites of insects. We hypothesized that growth of the nematode's mutualistic bacteria in the insect host may contribute to the production of cues used by the infective juveniles (IJs) in responding to potential hosts for infection. Specifically, we tested if patterns of bacterial growth could explain differences in CO2 production over the course of host infection. Growth of Xenorhabdus cabanillasii isolated from Steinernema riobrave exhibited the characteristic exponential and stationary growth phases. Other non-nematode symbiotic bacteria were also found in infected hosts and exhibited similar growth patterns to X. cabanillasii. Galleria mellonella larvae infected with S. riobrave produced two distinct peaks of CO2 occurring at 25.6-36 h and 105-16 h post-infection, whereas larvae injected with X. cabanillasii alone showed only one peak of CO2, occurring at 22.8-36.2h post-injection. Tenebrio molitor larvae infected with S. riobrave or injected with bacteria alone exhibited only one peak of CO2 production, which occurred later during S. riobrave infection (41.4-64.4h post-infection compared to 20.4-35.9h post-injection). These results indicate a relationship between bacterial growth and the first peak of CO2 in both host species, but not for the second peak exhibited in G. mellonella.
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Affiliation(s)
- Jayne M Christen
- Department of Entomology, Kansas State University, Manhattan, KS 66506, USA
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Abstract
Observations from nematodes to mammals indicate that insulin/insulin-like growth factor signaling (IIS) regulates lifespan. As in other organisms, IIS is conserved in mosquitoes and signaling occurs in multiple tissues. During bloodfeeding, mosquitoes ingest human insulin. This simple observation suggested that exogenous insulin could mimic the endogenous hormonal control of aging in mosquitoes, providing a new model to examine this phenomenon at the organismal and cellular levels. To this end, female Anopheles stephensi mosquitoes were maintained on diets containing human insulin provided daily in sucrose or three times weekly by artificial bloodmeal. Regardless of delivery route, mosquitoes provided with insulin at 1.7 x 10(-4) and 1.7 x 10(-3) micromol l(-1), doses 0.3-fold and 3.0-fold higher than non-fasting blood levels, died at a faster rate than controls. In mammals, IIS induces the synthesis of reactive oxygen species and downregulates antioxidants, events that increase oxidative stress and that have been associated with reduced lifespan. Insulin treatment of mosquito cells in vitro induced hydrogen peroxide synthesis while dietary supplementation reduced total superoxide dismutase (SOD) activity and manganese SOD activity relative to controls. The effects of insulin on mortality were reversed when diets were supplemented with manganese (III) tetrakis (4-benzoic acid) porphyrin (MnTBAP), a cell-permeable SOD mimetic agent, suggesting that insulin-induced mortality was due to oxidative stress. In addition, dietary insulin activated Akt/protein kinase B and extracellular signal-regulated kinase (ERK) in the mosquito midgut, suggesting that, as observed in Caenorhabditis elegans, the midgut may act as a 'signaling center' for mosquito aging.
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Affiliation(s)
- Mi-Ae Kang
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
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Spence KO, Lewis EE, Perry RN. Host-finding and invasion by entomopathogenic and plant-parasitic nematodes: evaluating the ability of laboratory bioassays to predict field results. J Nematol 2008; 40:93-98. [PMID: 19259525 PMCID: PMC2586539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Indexed: 05/27/2023] Open
Abstract
Directly viewing soil-dwelling entomopathogenic and plant-parasitic nematodes in situ is difficult, if not impossible. As a result, researchers have developed a diverse array of bioassays which assess nematode behavioral traits within arenas designed to simulate various aspects of the natural habitat. However, reliably rendering what we can see in the laboratory into accurate predictions of how nematodes achieve their objectives in the field is challenging. In the current review, we systemically assessed the goals and attributes of several of the assays most commonly used to investigate nematode host finding and host invasion behavior. By illuminating the relative strengths and limitations of each assay, we hope to improve our ability to develop meaningful predictions for the field.
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Affiliation(s)
- Kenneth O Spence
- Department of Nematology, UC Davis, Davis, CA 95616. Plant Pathology and Microbiology Department, Rothamsted Research, Harpenden, Herts. AL5 2JQ, UK
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Boina DR, Lewis EE, Bloomquist JR. Nematicidal activity of anion transport blockers against Meloidogyne incognita, Caenorhabditis elegans and Heterorhabditis bacteriophora. Pest Manag Sci 2008; 64:646-653. [PMID: 18407564 DOI: 10.1002/ps.1591] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
BACKGROUND Because methyl bromide has been phased out as a soil sterilant, new nematicides are urgently needed. Four different chemical classes of organic acids acting as anion transport (AT) blockers were tested against a free-living nematode, Caenorhabditis elegans Maupas, a plant-parasitic nematode, Meloidogyne incognita (Kofoid and White) Chitwood, and an entomopathogenic nematode, Heterorhabditis bacteriophora Poinar, in toxicity bioassays. The materials tested were DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid), 9-AC (anthracene-9-carboxylic acid), NPPB [5-nitro-2-(3-phenylpropylamino)benzoic acid] and IAA-94 (indanyloxyacetic acid). RESULTS All the compounds showed slowly developing nematicidal activity against second-stage juveniles of M. incognita and adults of C. elegans, but not against H. bacteriophora infective-stage juveniles. The LC(50) values of these compounds were < 50 mg L(-1) after 48 and 72 h incubation, while at 168 h incubation the LC(50) values were < 10 mg L(-1) for both sensitive species. Across both species and time, the LC(50) values generally differed no more than twofold among the four compounds tested in this study. In contrast, none of the compounds (200 mg L(-1)) caused more than control mortality to H. bacteriophora, even after 168 h of incubation. CONCLUSION These compounds are potential leads for commercial nematicides. The insensitivity to H. bacteriophora is consistent with the natural exposure of this nematode to DST (3,5-dihydroxy-4-isopropylstilbene), a stilbene produced by its symbiotic bacterium. Based on the known activity of the compounds used in this study, it is suggested that anion transporters form the probable target sites for DIDS, 9-AC, NPPB and IAA-94 in nematodes.
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Affiliation(s)
- Dhana Raj Boina
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
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Shapiro-Ilan D, Rojas MG, Morales-Ramos JA, Lewis EE, Tedders WL. Effects of host nutrition on virulence and fitness of entomopathogenic nematodes: Lipid- and protein-based supplements in Tenebrio molitor diets. J Nematol 2008; 40:13-19. [PMID: 19259513 PMCID: PMC2586524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Indexed: 05/27/2023] Open
Abstract
Entomopathogenic nematodes, Heterorhabditis indica and Steinernema riobrave, were tested for virulence and reproductive yield in Tenebrio molitor that were fed wheat bran diets with varying lipid- and protein-based supplements. Lipid supplements were based on 20% canola oil, peanut, pork or salmon, or a low lipid control (5% canola). Protein treatments consisted of basic supplement ingredients plus 0, 10, or 20% egg white; a bran-only control was also included. Some diet supplements had positive effects on nematode quality, whereas others had negative or neutral effects. All supplements with 20% lipids except canola oil caused increased T. molitor susceptibility to H. indica, whereas susceptibility to S. riobrave was not affected. Protein supplements did not affect host susceptibility, and neither lipid nor protein diet supplements affected reproductive capacity of either nematode species. Subsequently, we determined the pest control efficacy of progeny of nematodes that had been reared through T. molitor from different diets against Diaprepes abbreviatus and Otiorhynchus sulcatus. All nematode treatments reduced insect survival relative to the control (water only). Nematodes originating from T. molitor diets with the 0% or 20% protein exhibited lower efficacy versus D. abbreviatus than the intermediate level of protein (10%) or bran-only treatments. Nematodes originating from T. molitor lipid or control diets did not differ in virulence. Our research indicates that nutritional content of an insect host diet can affect host susceptibility to entomopathogenic nematodes and nematode fitness; therefore, host media could conceivably be optimized to increase in vivo nematode production efficiency.
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Affiliation(s)
- David Shapiro-Ilan
- USDA-ARS, SE Fruit and Nut Tree Research Laboratory, Byron, GA 31008 USDA-ARS, National Biological Control Laboratory, Stoneville, MS 38776 Department of Entomology, University of California-Davis, Davis CA 95616 Southeastern Insectaries, Inc., Perry, GA 31069
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Fujimoto A, Lewis EE, Cobanoglu G, Kaya HK. Dispersal, Infectivity and Sex Ratio of Early- or Late-Emerging Infective Juveniles of the Entomopathogenic Nematode Steinernema carpocapsae. J Nematol 2007; 39:333-337. [PMID: 19259508 PMCID: PMC2586514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Indexed: 05/27/2023] Open
Abstract
Differences in activity between infective juveniles (IJ) of the entomopathogenic nematode Steinernema carpocapsae that emerged directly from cadavers onto either a sand or agar substrate compared with those emerging from a cadaver into water and then being placed on the same substrate are known to occur. Differences between S. carpocapsae IJ that emerged directly from a cadaver vs. those that emerged from a cadaver and held in water were further elucidated. Dispersed and non-dispersed IJ from a cadaver were compared with those held in water between two time periods designated as early- (first two days) or late-emerging IJ (seventh day). A significantly greater proportion of early-emerging IJ from the cadaver treatment dispersed, compared with late-emerging IJ from a cadaver or either group of emerging IJ held in aqueous suspension. Moreover, IJ from cadavers were more infectious than those from the aqueous suspensions, and IJ that dispersed were less infectious than those that did not disperse. IJ that emerged early were mostly males, whereas those that emerged late were mostly females. For the non-dispersed IJ, most that emerged early were males, and those that emerged later were females, but among dispersing IJ, there was no difference in sex ratio between early- and late-emerging nematodes.
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Affiliation(s)
- Aki Fujimoto
- Department of Nematology, University of California, Davis, California 95616 Department of Biology, Hacettepe University Faculty of Science, 06800-Beytepe/Ankara, Turkey Present addresses: Kumiai Chemical Industry Co., Ltd., Ag. Chem. Discovery Laboratory, Life Science Research Institute, 3360 Kamo, Kikugawa-shi, Shizuoka, 4390031, Japan
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Molina JP, Dolinski C, Souza RM, Lewis EE. Effect of Entomopathogenic Nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) on Meloidogyne mayaguensis Rammah and Hirschmann (Tylenchida: Meloidoginidae) Infection in Tomato Plants. J Nematol 2007; 39:338-342. [PMID: 19259509 PMCID: PMC2586509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Indexed: 05/27/2023] Open
Abstract
Some studies suggest that entomopathogenic nematodes (EPN) affect plant-parasitic nematode populations. Here, the effects of live and dead IJ of Heterorhabditis bacteriophora JPM4, H. baujardi LPP7, Steinernema feltiae SN and S. carpocapsae All were evaluated against eggs and J2 of the plant-parasitic nematode Meloidogyne mayaguensis. According to treatment, 100 IJ were applied with 350 eggs, 350 J2 or 175 eggs + 175 J2 to tomato plants. Bioassays were conducted in March to May and repeated in September to November 2005. Both experiments lasted 9 weeks, and the variable evaluated was number of galls per plant. When eggs were used for infections in the first trial, plants exhibited lower gall number compared to control when live and dead H. baujardi IJ and live S. feltiae IJ were added (9.7, 4.5, 7.3 and 85.7 galls, respectively). In the second trial, live S. feltiae and S. carpocapasae IJ influenced gall formation compared to control (14.33, 14.57 and 168.02 galls, respectively). When J2 were used for infections, plants with live H. baujardi IJ presented less galls when compared to control in both trials (38.3 and 355.7 galls in the first trial and 145.2 and 326.2 in the second one, respectively). Infection with a mixture of J2 and eggs resulted in fewer galls than when live S. feltiae IJ were present in both trials, compared to control (38.3 and 44.2 galls vs. 275.3 and 192.2 galls, respectively). We conclude that H. baujardi and S. feltiae apparently may be inhibiting egg hatching and J2 infection.
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Affiliation(s)
- J P Molina
- Universidade Estadual do Norte Fluminense Darcy Ribeiro. CCTA/LEF, Av. Alberto Lamego 2000, CEP 28013-620, Campos dos Goytacazes. RJ, 28015-620 Brazil Departments of Nematology and Entomology, University of California-Davis, Davis, CA 95616
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Preisser EL, Gibson SE, Adler LS, Lewis EE. Underground herbivory and the costs of constitutive defense in tobacco. Acta Oecologica 2007. [DOI: 10.1016/j.actao.2006.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Christen JM, Campbell JF, Lewis EE, Shapiro-Ilan DI, Ramaswamy SB. Responses of the entomopathogenic nematode,Steinernema riobraveto its insect hosts,Galleria mellonellaandTenebrio molitor. Parasitology 2007; 134:889-98. [PMID: 17201992 DOI: 10.1017/s0031182006002101] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
SUMMARYPotential hosts for infective juveniles of entomopathogenic nematodes can vary considerably in quality based on the characteristics of the host species/stage, physiological status (e.g. stress, feeding on toxins), and infection status (heterospecific or conspecific infection). In this study, we investigated responses of the entomopathogenic nematodeSteinernema riobraveto hosts (Galleria mellonellaorTenebrio molitor) that were previously parasitized with conspecifics or injected with the nematode-symbiotic bacterium,Xenorhabdussp., to determine if there is a preference for previously parasitized/injected hosts and when this preference might occur. In no-choice bioassays, the number of juveniles infecting both host species decreased with increasing time post-infection. However, infective juveniles continued to infect previously parasitized hosts up to 72 h. Significant preference was exhibited byS. riobravefor 24 h post-infectionG. mellonellalarvae over uninfected, and by 24 h post-injectionG.mellonellalarvae over 48 h post-injection larvae. No significant preference was exhibited byS. riobraveforT. molitorhosts previously parasitized with conspecifics or those injected with bacteria in any treatment combination. Such preference for, or continued infection of parasitized insects, has the potential to impact nematode efficacy.
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Affiliation(s)
- J M Christen
- Department of Entomology, Kansas State University, Manhattan, KS 66506, USA
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Ramos-Rodríguez O, Campbell JF, Lewis EE, Shapiro-Ilan DI, Ramaswamy SB. Dynamics of carbon dioxide release from insects infected with entomopathogenic nematodes. J Invertebr Pathol 2007; 94:64-9. [PMID: 17054978 DOI: 10.1016/j.jip.2006.09.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Revised: 08/31/2006] [Accepted: 09/06/2006] [Indexed: 10/24/2022]
Abstract
The quality of an insect as a host to an entomopathogenic nematode infective juvenile depends in part on whether or not the insect is already infected and on the stage of that infection. Previous research has shown that nematode response to hosts can change after infection and that, for uninfected hosts, CO(2) can be an important cue used by infective stage juveniles during attraction. We hypothesized that CO(2) production from an insect changes after it is infected, and that these changes could influence nematode infection decisions. Changes in CO(2) released by two insect species (Galleria mellonella and Tenebrio molitor) after infection by one of four nematode species (Steinernema carpocapsae, Steinernema feltiae, Steinernema glaseri, or Steinernema riobrave) were measured. Measurements were taken every 2h from time of initial exposure to nematodes up to 224 h after infection. Dead (freeze-killed) and live uninfected insects were used as controls. Infected G. mellonella showed two distinct peaks of CO(2) production: one between 20 and 30 h and the other between 70 and 115 h after exposure to the nematodes. Peaks were up to two times higher than levels produced by uninfected insects. Infected T. molitor showed only one peak between 25 and 50h. We found differences in peak height and timing among nematode and insect species combinations. The influence of these changes in CO(2) production on IJ attraction and infection behavior remains to be determined.
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Ramos-Rodríguez O, Campbell JF, Christen JM, Shapiro-Ilan DI, Lewis EE, Ramaswamy SB. Attraction behaviour of three entomopathogenic nematode species towards infected and uninfected hosts. Parasitology 2006; 134:729-38. [PMID: 17176490 DOI: 10.1017/s0031182006001880] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
SUMMARYEntomopathogenic nematode infective juveniles are likely to encounter both uninfected and infected insects and host quality depends on the stage of the infection. We hypothesized that nematode response to infected hosts will change over the course of an infection. Here, we tested this hypothesis by focusing on the influence of host infection status on long-range attraction to host volatile cues. The attraction response of 3 nematode species (Steinernema carpocapsae, S. glaseri and S. riobrave) with different foraging strategies to infected and uninfected insects (Galleria mellonella and Tenebrio molitor) was tested at 24 h intervals from start of infection to emergence of infective juveniles from depleted host. As expected, based on their foraging strategies, S. carpocapsae was not very responsive to hosts, S. glaseri was highly responsive and S. riobrave was intermediate. Generally, the level of attraction did not change with time after infection and was similar between infected and uninfected hosts. An exception was S. glaseri infected T. molitor, which tended to be less attractive to S. glaseri than uninfected hosts. These results suggest that any influence of host infection status on infection behaviour is occurring at subsequent steps in the host-infection process than host attraction, or involves non-volatile cues.
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Affiliation(s)
- O Ramos-Rodríguez
- Department of Entomology, Kansas State University, Manhattan, KS, USA
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Shapiro-Ilan DI, Nyczepir AP, Lewis EE. Entomopathogenic Nematodes and Bacteria Applications for Control of the Pecan Root-Knot Nematode, Meloidogyne partityla, in the Greenhouse. J Nematol 2006; 38:449-54. [PMID: 19259462 PMCID: PMC2586469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Indexed: 05/27/2023] Open
Abstract
Meloidogyne partityla is a parasite of pecan and walnut. Our objective was to determine interactions between the entomopathogenic nematode-bacterium complex and M. partityla. Specifically, we investigated suppressive effects of Steinernema feltiae (strain SN) and S. riobrave (strain 7-12) applied as infective juveniles and in infected host insects, as well as application of S. feltiae's bacterial symbiont Xenorhabdus bovienii on M. partityla. In two separate greenhouse trials, the treatments were applied to pecan seedlings that were simultaneously infested with M. partityla eggs; controls received only water and M. partityla eggs. Additionally, all treatment applications were re-applied (without M. partityla eggs) two months later. Four months after initial treatment, plants were assessed for number of galls per root system, number of egg masses per root system, number of eggs per root system, number of eggs per egg mass, number of eggs per gram dry root weight, dry shoot weight, and final population density of M. partityla second-stage juveniles (J2). In the first trial, the number of egg masses per plant was lower in the S. riobrave-infected host treatment than in the control (by approximately 18%). In the second trial, dry root weight was higher in the S. feltiae-infected host treatment than in the control (approximately 80% increase). No other treatment effects were detected. The marginal and inconsistent effects observed in our experiments indicate that the treatments we applied are not sufficient for controlling M. partityla.
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Affiliation(s)
- David I Shapiro-Ilan
- USDA-ARS, Southeastern Fruit and Tree Nut Research Laboratory, 21 Dunbar Road, Byron, GA 31008 Dept. Nematology & Dept. of Entomology, University of California - Davis, Davis, CA 95616
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Kunkel BA, Shapiro-Ilan DI, Campbell JF, Lewis EE. Effect of Steinernema glaseri-infected host exudates on movement of conspecific infective juveniles. J Invertebr Pathol 2006; 93:42-9. [PMID: 16750218 DOI: 10.1016/j.jip.2006.04.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2005] [Revised: 04/14/2006] [Accepted: 04/19/2006] [Indexed: 10/24/2022]
Abstract
The entomopathogenic nematode's decision to infect a host is paramount because once the decision is made it is irrevocable; nematodes that invade a host either develop and achieve reproductive success, or they die. Entomopathogenic nematodes that have a cruiser foraging behavior, such as Steinernema glaseri, follow host-associated cues to locate insects to infect. Most of the host finding and infection dynamics research has focused on the infective juvenile nematodes' responses to cues from live insects such as host-associated volatiles and host contact cues. Few studies focus on how previously infected hosts influence infective juvenile infection behaviors. We investigated how exudates from nematode-infected hosts affect the behavior of S. glaseri infective juveniles. We hypothesized that the infective juvenile's behavioral response to cadavers would change as the state of a nematode-infected host changes during pathogenesis. We examined the effect of exudates collected from infected hosts on infective juvenile locomotory behavior. We detected no effects on nematode repulsion or attraction from exudates produced within the first 48h post-infection. We observed repulsion from accumulated exudates during the 3-48, 3-72, 3-120, and 3-144h intervals. Repulsion from exudates was observed during the 48-66, 72-90, and 120-138h intervals in experiments evaluating daily exudate emissions. The repellent effect of infected host exudates may result in an infective juvenile discriminating between suitable and unsuitable hosts.
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Affiliation(s)
- Brian A Kunkel
- USDA-ARS, Southeast Fruit and Tree Nut Research Lab, Byron, GA 31008, USA
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Pérez EE, Lewis EE. Use of Entomopathogenic Nematodes and Thyme Oil to Suppress Plant-Parasitic Nematodes on English Boxwood. Plant Dis 2006; 90:471-475. [PMID: 30786596 DOI: 10.1094/pd-90-0471] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A 2-year experiment was conducted to test suppression of plant-parasitic nematodes on English boxwood using entomopathogenic nematodes and 3.5% thyme oil formulated as Promax. Treatments were Steinernema riobrave formulated as BioVector and S. feltiae formulated as Nemasys, both applied at a rate of 2.5 billion infective juveniles/ha, thyme oil at rate of 9.3 liters/ha, and nontreated control. In the 2001 season, treatment with S. feltiae reduced (P ≤ 0.05) the population growth of Tylenchorhynchus sp. 7 days after treatment and Hoplolaimus sp. 30 and 60 days after treatment. Treatment with S. riobrave reduced (P ≤ 0.05) the population growth of all plant-parasitic nematode species at all sampling dates, with the exception of Mesocriconema sp. 30 days after treatment and Tylenchorhynchus sp. and Rotylenchus buxophilus 60 days after treatment. Treatment with thyme oil reduced (P ≤ 0.05) the population growth of all plant-parasitic nematode genera at all sampling dates except Tylenchorhynchus sp. and R. buxophilus 60 days after treatment. In the 2002 season, treatment with S. feltiae had no effect on nematode population growth. Treatment with S. riobrave reduced (P ≤ 0.05) the population growth of R. buxophilus 7 days after treatment, and all plant-parasitic nematodes 30 and 60 days after treatment except Hoplolaimus sp. 30 days after treatment and Mesocriconema sp. 60 days after treatment. Treatment with thyme oil reduced (P ≤ 0.05) the population growth at all sampling dates of plant-parasitic nematodes except Mesocriconema sp. 60 days after treatment.
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Affiliation(s)
- Enrique E Pérez
- Research Scientist, Monsanto Company, 700 Chesterfield Parkway West, Chesterfield, MO 63017
| | - Edwin E Lewis
- Associate Professor, Departments of Nematology and Entomology, University of California, Davis, CA 95616
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Ashley JL, Herbert DA, Lewis EE, Brewster CC, Huckaba R. Toxicity of three acaricides to Tetranychus urticae (Tetranychidae: Acari) and Orius insidiosus (Anthocoridae: Hemiptera). J Econ Entomol 2006; 99:54-9. [PMID: 16573323 DOI: 10.1093/jee/99.1.54] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Management for twospotted spider mite, Tetranychus urticae Koch, populations in peanut, Arachis hypogaea L., relies on acaricides. The outcomes of acaricide applications are most predictable when complete information on their toxicity and specificity is available. Specifically, the degrees to which acaricides impact different stages of T. urticae and natural enemies combined determine the overall efficacy of an acaricide application. The objectives of this study were to determine stage-specific direct and residual efficacies of three acaricides (fenpropathrin, etoxazole, and propargite) against T. urticae, and the direct and residual toxicity of the acaricides to Orius insidiosus (Say) adults. Direct toxicity of acaricides to T. urticae was measured on peanut cuttings. All acaricide treatments caused significant mortality to a mixed stage population of T. urticae, and mortality did not differ among the acaricides 7 d after treatment. When toxicity to eggs was tested, the proportion of eggs that hatched for all acaricide treatments was significantly lower than the control, with etoxazole and propargite causing 100% mortality. Exposure to acaricide residues caused < 30% mortality of T. urticae adults 1 and 2 d after treatment and was not significantly different from the control. Fenpropathrin and propargite caused 100% mortality and etoxazole caused > 50% mortality of O. insidious adults after direct exposure to the acaricides. Residual toxicity of acaricides to O. insidiosus adults varied but remained toxic to O. insidiosus longer than to T. urticae. Fenpropathrin had the longest residual effect on O. insidiosus adults, causing > 95% mortality after 14 d; etoxazole and propargite caused < 30% mortality after 14 d.
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Affiliation(s)
- Janet L Ashley
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
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Bruck DJ, Shapiro-Ilan DI, Lewis EE. Evaluation of application technologies of entomopathogenic nematodes for control of the black vine weevil. J Econ Entomol 2005; 98:1884-9. [PMID: 16539109 DOI: 10.1603/0022-0493-98.6.1884] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Black vine weevil, Otiorhynchus sulcatus (F.), is a severe pest of small fruit and nursery crops around the world. These studies were conducted to determine the efficacy of three species of entomopathogenic nematodes (Heterorhabditis marelatus, Heterorhabditis bacteriophora, and Steinernema riobrave) applied in infected host cadavers or as aqueous applications for black vine weevil larval control. Experiments were conducted in the greenhouse and outdoors. Application of three infected host cadavers or 40 infective juvenile nematodes (IJs) /cm2 were made to pots of Impatiens walleriana 5-7 d after larval infestation. Efficacy was assessed at 14 d in the greenhouse and at 14 and 28 d after nematode application in outdoor trials. In the greenhouse, all treatments with the exception the S. riobrave (cadaver and aqueous applications) provided nearly 100% efficacy after 14 d. The S. riobrave applications, although significantly better than the control, only provided 40-70% control and were not included in the outdoor trials. Nematode efficacy was slowed in the outdoor trials particularly in the cadaver applications. In the initial outdoor trial (soil temperatures < 12 degrees C), there were no significant differences between any nematode treatment and the control after 14 d. The nematode efficacy in the initial outdoor trial after 28 d was improved from the 14-d evaluation but not to the level seen in the second trial. In the second outdoor trial, in which soil temperatures were higher (> 12 degrees C), the aqueous applications of H. marelatus and H. bacteriophora provided nearly complete control after 14 d. The cadaver applications also provided nearly complete control in the second outdoor trial after 28 d. Even though the potential total number of IJs estimated per pot was higher in the cadaver-applied treatments, cool soil temperatures apparently delayed or potentially reduced IJ emergence from cadavers resulting in delayed control.
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Affiliation(s)
- Denny J Bruck
- USDA-ARS, Horticultural Crops Research Laboratory, 3420 N.W. Orchard Ave., Corvallis, OR 97330, USA.
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Caswell-Chen EP, Chen J, Lewis EE, Douhan GW, Nadler SA, Carey JR. Revising the standard wisdom of C. elegans natural history: ecology of longevity. ACTA ACUST UNITED AC 2005; 2005:pe30. [PMID: 16207928 PMCID: PMC2630584 DOI: 10.1126/sageke.2005.40.pe30] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Here, we consider that most of the research concerning Caenorhabditis elegans has been laboratory focused and that only limited research has directly considered the worm's biology relative to its natural history in the wild. We describe that, although the worm has traditionally been considered a soil nematode, we could not find it in soil but frequently recovered it from snails. Finally, we discuss how a better understanding of the natural history of C. elegans may enhance its usefulness as a model organism for studying aging and other phenomena.
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Affiliation(s)
- E P Caswell-Chen
- Department of Nematology, University of California, Davis, CA 95616, USA.
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Perez EE, Lewis EE, Shapiro-Ilan DI. Effect of application method on fitness of entomopathogenic nematodes emerging at different times. J Nematol 2004; 36:534-539. [PMID: 19262835 PMCID: PMC2620785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
The entomopathogenic nematode species Steinernema feltiae and Heterorhabditis bacteriophora were compared for survival and infectivity of infective juveniles (IJ) collected with a standard White trap (i.e., emerging from hosts and accumulating in water) and later applied to sand (treatment A) to IJ allowed to emerge from hosts into sand (treatment C). Percentage IJ survival and infectivity was compared between treatments for S. feltiae IJ that emerged between days 1 to 3 and days 4 to 6. For H. bacteriophora, percentage IJ survival and infectivity was compared between treatments only for infective juveniles that emerged between days 4 to 6. For S. feltiae IJ percentage survival and infectivity decreased with time (P </= 0.05) and was greater (P </= 0.05) for IJ from treatment C than for IJ from treatment A. For H. bacteriophora IJ percentage survival decreased (P </= 0.05) and percentage infectivity increased (P </= 0.05) with time. While percent survival was higher (P </= 0.05) for treatment C than for A, percent infectivity was not different between treatments.
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