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- Manduca sexta (3)
- Plant resistance (3)
- Buchloe dactyloides (2)
- Cochliomyia hominivorax (2)
- Phospholipase A2 (2)
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- Transgenic corn (2)
- Transgenic insect (2)
- Actin; Hermes (1)
- Aquatic contamination (1)
- Aquatic insects (1)
- Areawide management (1)
- Bacillus thuringiensis (1)
- Bacteria (1)
- Biological control (1)
- Biometry. (1)
- Blissus occiduus (1)
- Buffalograss (1)
- CYP4 (1)
- Campoletis (1)
- Carbaryl (1)
- Carbohydrates (1)
- Catalase (1)
- Chelonus (1)
- Chinch bug (1)
- Chrysomelidae (1)
- Corn (1)
- Cucurbitacins (1)
- Culex quinquefasciatus (1)
- Cyclooxygenase (1)
- Cytochrome P450 (1)
Articles 1 - 27 of 27
Full-Text Articles in Life Sciences
Buffalograss Germplasm Resistance To Blissus Occiduus (Hemiptera: Lygaeidae), Osman Gulsen, Tiffany Heng-Moss, Robert C. Shearman, P. Stephen Baenziger, Donald J. Lee, Frederick P. Baxendale
Buffalograss Germplasm Resistance To Blissus Occiduus (Hemiptera: Lygaeidae), Osman Gulsen, Tiffany Heng-Moss, Robert C. Shearman, P. Stephen Baenziger, Donald J. Lee, Frederick P. Baxendale
Department of Entomology: Faculty Publications
Plant germplasm collections may offer genetic variability useful in identifying insect resistance. The goal of this project was to evaluate buffalograss genotypes [Buchloe dactyloides (Nutt.) Engelm.] for resistance to the chinch bug, Blissus occiduus Barber (Hemiptera: Lygaeidae), and to relate resistance to ploidy level, chinch bug number, and pubescence. Forty-eight buffalograss genotypes from diverse geographic locations were evaluated in replicated studies under greenhouse conditions. Of the genotypes studied, four were highly resistant, 22 were moderately resistant, 19 were moderately susceptible, and three were highly susceptible to chinch bug damage. The mean number of chinch bugs was significantly different among …
Monitoring Western Corn Rootworm (Coleoptera: Chrysomelidae) Susceptibility To Carbaryl And Cucurbitacin Baits In The Areawide Management Pilot Program, Blair Siegfried, Lance J. Meinke, Srivinas Parimi, Michael E. Scharf, Timothy J. Nowatzki, X. Zhou, Laurence D. Chandler
Monitoring Western Corn Rootworm (Coleoptera: Chrysomelidae) Susceptibility To Carbaryl And Cucurbitacin Baits In The Areawide Management Pilot Program, Blair Siegfried, Lance J. Meinke, Srivinas Parimi, Michael E. Scharf, Timothy J. Nowatzki, X. Zhou, Laurence D. Chandler
Department of Entomology: Faculty Publications
Area-wide pest management involves the uniform application of a pest control strategy over wide geographic areas. Therefore, these programs are likely to impose intense selective pressures, and the risk for resistance development among pest species for which area-wide management programs are implemented is likely to be high. Pilot studies for area-wide management of western corn rootworm, Diabrotica virgifera virgifera LeConte, were conducted from 1996 to 2002 at four different sites across the Corn Belt. This program used cucurbitacin baits to deliver high doses of a traditional neurotoxic insecticide (carbaryl) to individual insects while reducing the overall rate of insecticide use. …
Activity Of Gut Proteinases From Cry1ab-Selected Colonies Of The European Corn Borer, Ostrinia Nubilalis (Lepidoptera: Crambidae), Herbert A. A. Siqueira, Kenneth Nickerson, Daniel Moellenbeck, Blair D. Siegfried
Activity Of Gut Proteinases From Cry1ab-Selected Colonies Of The European Corn Borer, Ostrinia Nubilalis (Lepidoptera: Crambidae), Herbert A. A. Siqueira, Kenneth Nickerson, Daniel Moellenbeck, Blair D. Siegfried
Department of Entomology: Faculty Publications
Susceptibility to the Cry1Ab protoxin and toxin from Bacillus thuringiensis (Berliner) and activity of gut proteinases were assessed in both susceptible and Cry1Ab-selected colonies of European corn borer, Ostrinia nubilalis (Hübner). Resistance in two different selected colonies was at least 6- and 15-fold for the Cry1Ab protoxin and 108- and 484-fold for the Cry1Ab toxin. Activities of trypsin-like, chymotrypsin-like and elastase-like proteinases were variable among the colonies tested and not indicative of a major contribution to Cry1Ab resistance. Activation of the 130-kDa Cry1Ab protoxin occurred rapidly in all colonies, with no apparent differences among colonies. In addition, there were no …
Genetic Divergence Among Tomato Leafminer Populations Based On Aflp Analysis, Fábio Akiyoshi Suinaga, Vicente Wagner Dias Casali, Marcelo Picanço, John E. Foster
Genetic Divergence Among Tomato Leafminer Populations Based On Aflp Analysis, Fábio Akiyoshi Suinaga, Vicente Wagner Dias Casali, Marcelo Picanço, John E. Foster
Department of Entomology: Faculty Publications
The objective of this work was to determine the genetic differences among eight Brazilian populations of the tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), from the states of Espírito Santo (Santa Tereza), Goiás (Goianápolis), Minas Gerais (Uberlândia and Viçosa), Pernambuco (Camocim de São Félix), Rio de Janeiro (São João da Barra) and São Paulo (Paulínia and Sumaré), using the amplified fragment length polymorphism (AFLP) technique. Fifteen combinations of EcoRI and MseI primers were used to assess divergence among populations. The data were analyzed using unweighted pair-group method, based on arithmetic averages (UPGMA) bootstrap analysis and principal coordinate analysis. Using a …
Postlarval Fitness Of Transgenic Strains Of Cochliomyia Hominivorax (Diptera: Calliphoridae), Margaret L. Allen, Dennis Berkebile, Steven R. Skoda
Postlarval Fitness Of Transgenic Strains Of Cochliomyia Hominivorax (Diptera: Calliphoridae), Margaret L. Allen, Dennis Berkebile, Steven R. Skoda
Department of Entomology: Faculty Publications
Eight transgenic strains of Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae) were compared with the wild-type parental laboratory strain (P95) in colony. Measurements of average weight of pupae, percentage of adults emerging from pupae, ratio of males to total emerged adults, and mating competitiveness were analyzed. The parental strain colony was subcultured and exposed to handling procedures equivalent to transgenic strains for valid comparison of overall colony fitness. None of the transgenic colonies exhibited significantly lower fitness characteristics than the control parental colony. One transgenic colony had a higher ratio of adults emerging from pupae, and five colonies had higher average pupal …
Cross-Resistance Of Cry1ab-Selected Ostrinia Nubilalis (Lepidoptera: Crambidae) To Bacillus Thuringiensis Δ -Endotoxins, Herbert A.A. Siqueria, Daniel J. Moellenbeck, Terrence A. Spencer, Blair D. Siegfried
Cross-Resistance Of Cry1ab-Selected Ostrinia Nubilalis (Lepidoptera: Crambidae) To Bacillus Thuringiensis Δ -Endotoxins, Herbert A.A. Siqueria, Daniel J. Moellenbeck, Terrence A. Spencer, Blair D. Siegfried
Department of Entomology: Faculty Publications
Corn plants expressing the toxin from Bacillus thuringiensis (Berliner) have proven to be effective in controlling lepidopteran pests such as the European corn borer, Ostrinia nubilalis (Hubner) (Lepidoptera: Crambidae). Several Bt toxins are being tested and incorporated into crop genomes, although tests for cross-resistance among different toxins have been limited by a lack of resistant colonies. Four different colonies of O. nubilalis selected with full-length Cry1Ab incorporated into artificial diet developed significant levels of resistance (2.0- to 10-fold) within 10 generations. Additionally, selection with Cry1Ab resulted in decreased susceptibility to a number of other toxins to which the selected colonies …
Characterization Of Oxidative Enzyme Changes In Buffalograsses Challenged By Blissus Occiduus, Tiffany Heng-Moss, Gautam Sarath, Frederick P. Baxendale, Dana Novak, Shauna Bose, Xinhi Ni, Sharron Quisenberry
Characterization Of Oxidative Enzyme Changes In Buffalograsses Challenged By Blissus Occiduus, Tiffany Heng-Moss, Gautam Sarath, Frederick P. Baxendale, Dana Novak, Shauna Bose, Xinhi Ni, Sharron Quisenberry
Department of Entomology: Faculty Publications
This research investigated the role of oxidative enzymes in the defense response of buffalograss, Buchloe dactyloides (Nuttall) Engelmann, to Blissus occiduus Barber. Changes in catalase and peroxidase activity were observed in both resistant and susceptible buffalograsses in response to chinch bug feeding. Susceptible plants were shown to have a lower level of catalase activity compared with their respective control plants. By contrast, catalase activities of resistant plants were similar between infested and control buffalograsses throughout the study. Resistant plants had higher levels of peroxidase activity compared with their control plants, whereas peroxidase activities for control and infested susceptible plants remained …
Synthesis Of The Four Stereoisomers Of 7-Acetoxy-15-Methylnonacosane, A Component Of The Female Sex Phermone Of The Screwworm Fly, Cocliomyia Hominivorax), Kenji Mori, Takashi Ohtaki, Hiroshi Ohrui, Dennis Berkebile, David A. Carlson
Synthesis Of The Four Stereoisomers Of 7-Acetoxy-15-Methylnonacosane, A Component Of The Female Sex Phermone Of The Screwworm Fly, Cocliomyia Hominivorax), Kenji Mori, Takashi Ohtaki, Hiroshi Ohrui, Dennis Berkebile, David A. Carlson
Department of Entomology: Faculty Publications
The four stereoisomers of 7-acetoxy-15-methylnonacosane (1), a component of the female sex pheromone of the New World screwworm fly (Cocliomyia hominivorax) were synthesized. The stereogenic center at C-15 of 1 originated from that of the enantiomers of citronellal, and that at C-7 was generated by lipase-catalyzed asymmetric acetylation of (3RS,11R)- and (3RS,11S)-17-methyl-1-trimethylsilylpentacos-1-yn-3-ol (13). Three of the stereoisomers of 1 showed equivalent good pheromone activity, while the activity of (7R,15R)-1 was weak.
Piggybac Transformation Of The New World Screwworm, Cochliomyia Hominivorax, Produces Multiple Distinct Mutant Strains, M.L. Allen, A.M. Handler, Dennis Berkebile, S.R. Skoda
Piggybac Transformation Of The New World Screwworm, Cochliomyia Hominivorax, Produces Multiple Distinct Mutant Strains, M.L. Allen, A.M. Handler, Dennis Berkebile, S.R. Skoda
Department of Entomology: Faculty Publications
Sterile insect technique (SIT) programs are designed to eradicate pest species by releasing mass-reared, sterile insects into an infested area. The first major implementation of SIT was the New World Screwworm Eradication Program, which successfully eliminated the New World screwworm (NWS), Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), from the Continental US, Mexico and much of Central America. Ionizing radiation is currently used for sterilization, but transgenic insect techniques could replace this method, providing a safer, more cost-effective alternative. Genetic transformation methods have been demonstrated in NWS, and verified by Southern blot hybridization, PCR and sequencing of element insertion junctions. A lethal …
Synthesis Of The Four Stereoisomers Of 6-Acetoxy-19-Methylnonacosane, The Most Potent Component Of The Female Sex Pheromone Of The New World Screwworm Fly, With Special Emphasis On Partial Racemization In The Course Of Catalytic Hydrogenation, Kenji Mori, Takashi Ohtaki, Hiroshi Ohrui, Dennis Berkebile, David A. Carlson
Synthesis Of The Four Stereoisomers Of 6-Acetoxy-19-Methylnonacosane, The Most Potent Component Of The Female Sex Pheromone Of The New World Screwworm Fly, With Special Emphasis On Partial Racemization In The Course Of Catalytic Hydrogenation, Kenji Mori, Takashi Ohtaki, Hiroshi Ohrui, Dennis Berkebile, David A. Carlson
Department of Entomology: Faculty Publications
Starting from the enantiomers of citronellal and 1-octyn-3- ol, all four stereoisomers of 6-acetoxy-19-methylnonacosane were synthesized with sufficiently high stereochemical purities (more than 90% ee at C-6; about 97% ee at C-19) for their biological testing as the female sex pheromone of the screwworm fly (Cochliomyia hominivorax). All four isomers showed strong pheromone activity even at 1 μg, and no significant difference was observed in their potency. Adams’ platinum oxide was found to cause partial racemization of enantiomerically pure secondary propargylic alcohols in the course of their catalytic hydrogenation to saturated and secondary alcohols, while palladium-charcoal was less …
Fitness Characteristics Of Transgenic Strains Of Cochliomyia Hominivorax, The New World Screwworm, Margaret Allen, Dennis Berkebile, Steven Skoda
Fitness Characteristics Of Transgenic Strains Of Cochliomyia Hominivorax, The New World Screwworm, Margaret Allen, Dennis Berkebile, Steven Skoda
Department of Entomology: Faculty Publications
Sterile insect technique (SIT) programs are designed to eradicate pest species by release of mass-reared, sterile insects into an infested area. The first large-scale implementation of SIT was the New World Screwworm Eradication Program, which successfully eliminated the New World screwworm (NWS), Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae) from the Continental US, Mexico, and most of Central America. Ionizing radiation is currently used for sterilization, but transgenic insect techniques could hypothetically replace this method, providing a safer, more cost-effective alternative. Genetic transformation methods have recently been demonstrated in NWS. Some key issues involved in mass release of sterile insects revolve around …
Turfgrass, Crop, And Weed Hosts Of Blissus Occiduus (Hemiptera: Lygaeidae), Thomas E. Eickhoff, Frederick P. Baxendale, Tiffany Heng-Moss, Erin E. Blankenship
Turfgrass, Crop, And Weed Hosts Of Blissus Occiduus (Hemiptera: Lygaeidae), Thomas E. Eickhoff, Frederick P. Baxendale, Tiffany Heng-Moss, Erin E. Blankenship
Department of Entomology: Faculty Publications
Blissus occiduus Barber is an important pest of buffalograss, Buchloe dactyloides (Nuttall) Engelmann, turf. No-choice studies documented the susceptibility of selected turfgrasses, crops, and weeds to B. occiduus feeding. Highly to moderately susceptible grasses included buffalograss; yellow Setaria glauca (L.) and green foxtail Setaria viridis (L.); Kentucky bluegrass, Poa pratensis L.; perennial ryegrass, Lolium perenne L.; brome, Bromus spp. Leyss.; zoysiagrass, Zoysia japonica Steudel; Bermuda grass, Cynodon dactylon (L.) Pers.; sorghum, Sorghum bicolor (L.) Moench; tall fescue, Festuca arundinacea Schreb.; and barley Hordeum vulgare (L.). Slightly to nonsusceptible grasses included Þne fescue, Festuca ovina hirtula L.; rye, Secale cereale L.; …
Partial Purification And Characterization Of A Methyl-Parathion Resistance-Associated General Esterase In Diabrotica Virgifera Virgifera (Coleoptera: Chrysomelidae), Xuguo Zhou, Michael E. Scharf, Gautam Sarath, Lance J. Meinke, Laurence D. Chandler, Blair Siegfried
Partial Purification And Characterization Of A Methyl-Parathion Resistance-Associated General Esterase In Diabrotica Virgifera Virgifera (Coleoptera: Chrysomelidae), Xuguo Zhou, Michael E. Scharf, Gautam Sarath, Lance J. Meinke, Laurence D. Chandler, Blair Siegfried
Department of Entomology: Faculty Publications
Increased hydrolytic metabolism of organophosphate insecticides has been associated with resistance among Nebraska western corn rootworm populations. In this study, resistance-associated esterases were partially purified by differential centrifugation, ion exchange, and hydroxyapatite column chromatography, with a final purification factor of 100-fold and recovery of approximately 10%. Kinetic analysis of the partially purified enzyme indicated that the Km of the group II esterases was identical for the two populations, although Vmax was consistently threefold higher in the resistant population. A putative esterase, DvvII, was further purified to homogeneity by preparative polyacrylamide gel electrophoresis. DvvII is a monomer with a …
Flight Muscle–Specific Expression Of Act88f: Gfp In Transgenic Culex Quinquefasciatus Say (Diptera: Culicidae), Margaret L. Allen, Bruce M. Christensen
Flight Muscle–Specific Expression Of Act88f: Gfp In Transgenic Culex Quinquefasciatus Say (Diptera: Culicidae), Margaret L. Allen, Bruce M. Christensen
Department of Entomology: Faculty Publications
A strategy to engineer a strain of Culex mosquitoes refractory to filarial transmission is described. A requirement for success of the strategy is identification of a flight muscle–specific promoter that functions in the mosquito. A GFP marker gene under the control of the promoter region of the Drosophila melanogaster act88F gene was inserted into the genome of Culex quinquefasciatus. Transformation was confirmed by Mendelian genetics. Hy-bridization of a genomic Southern blot to a radiolabeled probe verified that the entire donor plasmid integrated into the mosquito genome. GFP expression in the transgenic mosquitoes was restricted to the flight muscles.
Supercooling Differences In The Eastern Subterranean Termite (Isoptera: Rhinotermitidae), Brian J. Cabrera, Shripat T. Kamble
Supercooling Differences In The Eastern Subterranean Termite (Isoptera: Rhinotermitidae), Brian J. Cabrera, Shripat T. Kamble
Department of Entomology: Faculty Publications
Supercooling points were determined for untreated field-collected and untreated laboratory-maintained Reticulitermes flavipes (Kollar) workers and soldiers. Workers treated with antibiotics or had their hindgut-protozoa removed by exposing them to oxygen under pressure to determine the effects of absence of the hindgut fauna on supercooling. Supercooling points were compared be-tween live and freshly killed workers to determine whether supercooling in this species might be simply due to the biochemical properties of body fluids. Laboratory-maintained workers were also subjected to desiccation, starvation, or atmospheric pressure to determine their effects on supercool-ing. Supercooling points were lowest for laboratory workers treated with antibiotics and …
Molecular Differentiation Of Two Sibling Species Of The Black Fly Simulium Vittatum (Diptera: Simuliidae) Based On Random Amplified Polymorphic Dna, G. A. Duncan, P. H. Alder, K. P. Pruess, T. O. Powers
Molecular Differentiation Of Two Sibling Species Of The Black Fly Simulium Vittatum (Diptera: Simuliidae) Based On Random Amplified Polymorphic Dna, G. A. Duncan, P. H. Alder, K. P. Pruess, T. O. Powers
Department of Entomology: Faculty Publications
Larvae of the black fly morphospecies Simulium vittatum from Colorado, Montana, Nebraska, and New Hampshire were cytologically identified as either the IS-7 or the IIIL-1 cytospecies. DNA was PCR amplified from cytotyped larvae using eight 10-mer primers, labeled with 33P, and run on pol-yacrylamide gels. The entire data set of 96 amplicons produced incomplete separation of the two cytospecies when subjected to neighbor-joining and maximum parsimony analyses. However, when analyzed within geographical regions, separate species status was supported. Bootstrap support for distinctness of the two cytospecies was best in Colorado where they were collected in true sympatry. The IS-7 cytospecies …
Impact Of Ceutorhynchus Litura Feeding On Root Carbohydrate Levels In Canada Thistle (Cirsium Arvense), Gary L. Hein, Robert G. Wilson
Impact Of Ceutorhynchus Litura Feeding On Root Carbohydrate Levels In Canada Thistle (Cirsium Arvense), Gary L. Hein, Robert G. Wilson
Department of Entomology: Faculty Publications
Canada thistle is a serious perennial weed found throughout the northern regions of the United States and Canada. The weevil, Ceutorhynchus litura (F.), was first released in Canada in 1965 as a potential biological control agent for Canada thistle; however, its impact as a control agent has been sporadic. The objective of this study was to characterize C. litura impacts on the carbohydrate profile in Canada thistle roots through the growing season and to evaluate the potential for this biological control agent in causing stress to Canada thistle. Field plots, infested with C. litura, were established and extensively sampled …
Alfalfa: Simulated Clover Leaf Weevil Injury And Alfalfa Yield And Quality, Rodney A. Madsen, Thomas E. Hunt, Leon G. Higley
Alfalfa: Simulated Clover Leaf Weevil Injury And Alfalfa Yield And Quality, Rodney A. Madsen, Thomas E. Hunt, Leon G. Higley
Department of Entomology: Faculty Publications
The clover leaf weevil (Hypera punctata F.) is a sporadic but potentially serious pest of alfalfa (Medicago sativa L.). Feeding of newly emerged adult fourth instar clover leaf weevil was simulated in a field study at the University of Nebraska Haskell Agricultural Research Lab near Concord, Nebraska, in May 2001 and 2002. Twelve 1- by 1-m plots were arranged in a randomized complete block design with three treatments and four replications. Treatments consisted of two levels of simulated clover leaf weevil defoliation of alfalfa and an undefoliated check. Leaflets were removed over 10 d. Dry matter yield and …
Effect Of Environment On Resistance To The European Corn Borer (Lepidoptera: Crambidae) In Maize, David B. Willmot, Bruce E. Hibbard, Larry L. Darrah, Linda M. Pollak, Kevin Montgomery, Richard C. Pratt, Craig A. Abel, James A. Hawk, Tecle Weldekidan, John E. Foster
Effect Of Environment On Resistance To The European Corn Borer (Lepidoptera: Crambidae) In Maize, David B. Willmot, Bruce E. Hibbard, Larry L. Darrah, Linda M. Pollak, Kevin Montgomery, Richard C. Pratt, Craig A. Abel, James A. Hawk, Tecle Weldekidan, John E. Foster
Department of Entomology: Faculty Publications
The European corn borer, Ostrinia nubilalis (Hu¨ bner) (Lepidoptera: Crambidae), is a major pest of maize, Zea mays L., in many temperate parts of the world. Genotype-by-environment interaction effects can make relative performance unpredictable and may hamper selection for resistance to European corn borer. The objective of this study was to determine the effect of environment on genotypic reaction to European corn borer resistance in maize. A set of 12 maize inbred lines was chosen to represent a range of European corn borer responses. Eleven testing environments ranged from Delaware, Ohio, Illinois, Iowa, Nebraska, Missouri, to Mississippi. For length of …
Phospholipase A2 In Salivary Glands Isolated From Tobacco Hornworms, Manduca Sexta, Hasan Tunaz, David W. Stanley
Phospholipase A2 In Salivary Glands Isolated From Tobacco Hornworms, Manduca Sexta, Hasan Tunaz, David W. Stanley
Department of Entomology: Faculty Publications
We describe a phospholipase A2 (PLA2) associated with the salivary glands of tobacco hornworms, Manduca sexta. This enzyme is able to hydrolyze arachidonic acid from the sn-2 position of PLs. Addition of the calcium chelator, EGTA, or calcium, to the Tris reaction buffer impaired the PLA2 activity, from which we infer the enzyme requires very low concentrations of calcium or perhaps other ions for optimal activity. PLA2 activity was sensitive to protein concentration (highest activity at 25 μg protein per μl), reaction time (optimal at 30 min), buffer pH (optimal at pH 8–10), …
The Bacterium Xenorhabdus Nematophila Inhibits Phospholipases A2 From Insect, Prokaryote, And Vertebrate Sources, Youngjin Park, Yonggyun Kim, David Stanley
The Bacterium Xenorhabdus Nematophila Inhibits Phospholipases A2 From Insect, Prokaryote, And Vertebrate Sources, Youngjin Park, Yonggyun Kim, David Stanley
Department of Entomology: Faculty Publications
The bacterium Xenorhabdus nematophila is a virulent insect pathogen. Part of its pathogenicity is due to impairing cellular immunity by blocking biosynthesis of eicosanoids, the major recognized signal transduction system in insect cellular immunity. X. nematophila inhibits the first step in eicosanoid biosynthesis, phospholipase A2 (PLA2). Here we report that the bacterium inhibits PLA2 from two insect immune tissues, hemocytes and fat body, as well as PLA2s selected to represent a wide range of organisms, including prokaryotes, insects, reptiles, and mammals. Our finding on a bacterial in-hibitor of PLA2 activity contributes new insight into …
An Entomopathogenic Bacterium, Xenorhabdus Nematophila, Inhibits Hemocytic Phospholipase A2 (Pla2) In Tobacco Hornworms, Manduca Sexta, Youngjin Park, Yonggyun Kim, Hasan Tunaz, David W. Stanley
An Entomopathogenic Bacterium, Xenorhabdus Nematophila, Inhibits Hemocytic Phospholipase A2 (Pla2) In Tobacco Hornworms, Manduca Sexta, Youngjin Park, Yonggyun Kim, Hasan Tunaz, David W. Stanley
Department of Entomology: Faculty Publications
The entomopathogenic bacterium, Xenorhabdus nematophila, induces immunodepression in target insects and finally leads to lethal septicemia of the infected hosts. A hypothesis has been raised that the bacteria inhibit eicosanoid-biosynthesis pathway to interrupt immune signaling of the infected hosts. Here, we show direct evidence that X. nematophila inhibits the activity of phospholipase A2 (PLA2), the initial step in the eicosanoid-biosynthesis pathway. Inhibition of PLA2 was dependent on both incubation time with X. nematophila and the bacterial concentration in in vitro PLA2 preparations of Manduca sexta hemocytes. While living bacteria inhibited PLA2 activity, heat-killed X. nematophila rather increased PLA2 activity. X. …
Atrazine Induction Of A Family 4 Cytochrome P450 Gene In Chironomus Tentans (Diptera: Chironomidae), Diana K. Londono, Blair D. Siegfried, Michael J. Lydy
Atrazine Induction Of A Family 4 Cytochrome P450 Gene In Chironomus Tentans (Diptera: Chironomidae), Diana K. Londono, Blair D. Siegfried, Michael J. Lydy
Department of Entomology: Faculty Publications
Cytochrome P450-dependent microsomal monooxygenase (P450) activity was measured in control and atrazine-exposed third instar midge larvae, Chironomus tentans. Significantly elevated O-demethylase activity was observed in gut homogenates taken from midges exposed to atrazine concentrations from 1 to 10 ppm for 90 h. No significant induction was observed at atrazine concentrations below 1 ppm. A region of a cytochrome P450 family 4 gene was amplified and sequenced from C. tentans larvae. Alignments of inferred amino acid sequences with other insect CYP4 gene homologues indicate a high degree of similarity. Northern blot analysis employing the CYP4 gene fragment as a …
Within-Field Distribution Of The Sunflower Midge (Diptera: Cecidomyiidae), E. W. Hodgson, I. V. Macrae, Gary J. Brewer
Within-Field Distribution Of The Sunflower Midge (Diptera: Cecidomyiidae), E. W. Hodgson, I. V. Macrae, Gary J. Brewer
Department of Entomology: Faculty Publications
The sunßower midge, Contarinia schulzi Gagne (Diptera: Cecidomyiidae), is a pest of cultivated sunflower (Helianthus annuus L.). Larval feeding can cause damage and yield loss to the sunflower head. Adult emergence is extended and larvae are well protected in the sunflower receptacle, making chemical control methods difficult and expensive. Sunflower midge enter sunflower fields at the edges but fieldwide distributions occur, although the dynamics are not fully understood. Two commercial fields in 1999 and one field in 2000 were systematically sampled by dividing each field into fixed sample points. Mean egg and larval densities from each sample point were …
Sunflower Beetle (Coleoptera: Chrysomelidae): Pattern Of Larval Distribution And Parasitism In Cultivated Sunflower Fields, Gary J. Brewer, Laurence D. Charlet
Sunflower Beetle (Coleoptera: Chrysomelidae): Pattern Of Larval Distribution And Parasitism In Cultivated Sunflower Fields, Gary J. Brewer, Laurence D. Charlet
Department of Entomology: Faculty Publications
The sunflower beetle, Zygogramma exclamationis (Fabricius), is a major pest of commercial sunflower, Helianthus annuus L. (Asteraceae), in the Plains area of central North America. Although an economic injury level for the sunflower beetle has been determined, in-field distributions of the larvae and their natural enemies have not been described. Over a three year period, fields were sampled for sunflower beetle larvae and for larvae of the endoparasitoid, Myiopharus macellus (Reinhard). Sunflower beetle larvae were generally found to have aggregated distributions. Knowledge of the distribution pattern will allow the development of more efficient sunflower beetle sampling protocols. Parasitism rates of …
Natural Distribution Of Hymenopteran Parasitoids Of Spodoptera Frugiperda (Lepidoptera: Noctuidae) Larvae In Mexico, Jaime Molina-Ochoa, James E. Carpenter, Roberto Lezama-Gutiérrez, John E. Foster, Martín González-Ramírez, César Andres Angel-Sahagún, Javier Farías-Larios
Natural Distribution Of Hymenopteran Parasitoids Of Spodoptera Frugiperda (Lepidoptera: Noctuidae) Larvae In Mexico, Jaime Molina-Ochoa, James E. Carpenter, Roberto Lezama-Gutiérrez, John E. Foster, Martín González-Ramírez, César Andres Angel-Sahagún, Javier Farías-Larios
Department of Entomology: Faculty Publications
Se llevó a cabo un inventario de parasitoides de larvas del gusano cogollero, Spodoptera frugiperda (J. E. Smith) (FAW) colectadas principalmente de maizales en estado de verticilio en seis estados mexicanos durante Agosto y Septiembre de 2000. Trece géneros de parasitoides himenópteros fueron recuperados, representando a tres familias, Braconidae: Aleoides, Chelonus, Cotesia, Glyptapanteles, Homolobus, y Meteorus); Ichneumonidae: Campoletis, Eiphosoma, Ophion, y Pristomerus; y Eulophidae: Aprostocetus, Euplectrus, y Horismenus. De un total de 5591 larvas colectadas, 772 produjeron parasitoides, para una tasa de parasitismo de 13.8%. La tasa de parasitismo más alta para una colecta simple fué …
Lipopolysaccharide Evokes Microaggregation Reactions In Hemocytes Isolated From Tobacco Hornworms, Manduca Sexta, Jon S. Miller, David W. Stanley
Lipopolysaccharide Evokes Microaggregation Reactions In Hemocytes Isolated From Tobacco Hornworms, Manduca Sexta, Jon S. Miller, David W. Stanley
Department of Entomology: Faculty Publications
Insect cellular immune reactions to bacterial infection include nodule formation. Eicosanoids mediate several cellular actions in the nodulation process, including formation of hemocyte microaggregates, an early step. In previous work, we reported that isolated hemocytes produce and secrete eicosanoids that influence hemocyte behavior in response to bacterial challenge. We also reported that microaggregate formation in response to challenge was mediated by prostaglandins (PGs), but not by products of the lipoxygenase (LOX) pathways. In this paper we describe experiments designed to test the idea that exposing isolated hemocytes to lipopolysaccharide (LPS) evokes formation of hemocyte microaggregates and this cellular action is …