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May R Berenbaum - One of the best experts on this subject based on the ideXlab platform.

  • Differential regulation of cytochrome P450 genes associated with biosynthesis and detoxification in bifenthrin-resistant populations of navel orangewom (Amyelois transitella).
    'Public Library of Science (PLoS)', 2021
    Co-Authors: Mark R. Demkovich, Joel P. Siegel, Bradley S. Higbee, Bernarda Calla, Esther Ngumbi, May R Berenbaum
    Abstract:

    Pyrethroid resistance was first reported in 2013 for the navel orangeworm, Amyelois transitella, but the genetic underpinnings of pyrethroid resistance are unknown. We investigated the role of cytochrome P450 monooxygenases (P450s) belonging to the CYP3 and CYP4 clans using colonies derived from individuals collected in 2016 from almond orchards in two counties. One colony (ALM) originated from an almond orchard in Madera County with no reported pyrethroid resistance and the second colony (R347) originated from the same Kern County orchard where pyrethroid resistance was first reported. We used high-throughput quantitative real-time PCR (qRT-PCR) analyses of 65 P450s in the CYP3 and CYP4 clans of A. transitella to identify P450s induced by bifenthrin and associated with pyrethroid resistance. Nine P450s were constitutively overexpressed in R347 compared to ALM, including CYP6AE54 (11.7-fold), belonging to a subfamily associated with metabolic pesticide detoxification in Lepidoptera and CYP4G89 (33-fold) belonging to a subfamily associated with cuticular hydrocarbon (CHC) synthesis and resistance via reduced pesticide penetrance. Cuticular hydrocarbons analysis revealed that R347 produced twice as many total CHCs in the egg and adult stages as ALM. Topical toxicity bioassays for R347 determined that egg mortality was reduced at low bifenthrin concentrations and larval mortality was reduced at high concentrations of bifenthrin compared to ALM. Our discovery of both changes in metabolism and production of CHCs for R347 have implications for the possible decreased efficacy of other classes of insecticide used to control this insect. The threat of widespread pyrethroid resistance combined with the potential for cross-resistance to develop through the mechanism of reduced penetrance warrants developing management strategies that facilitate insecticide passage across the cuticle

  • Factors Associated with Variation in Cuticular Hydrocarbon Profiles in the Navel Orangeworm, Amyelois transitella (Lepidoptera: Pyralidae)
    Journal of Chemical Ecology, 2020
    Co-Authors: Esther N. Ngumbi, Jocelyn G. Millar, Lawrence M. Hanks, Andrew V. Suarez, May R Berenbaum
    Abstract:

    Cuticular hydrocarbons (CHCs) are the main components of the epicuticular wax layer that in many insects functions as a barrier against desiccation. CHCs also play many other roles, including serving as sex pheromones, kairomones, primer pheromones, and colony-, caste-, species- and sex-recognition signals. In insects, CHC profiles can vary depending upon age, species, sex, and strain. Understanding factors associated with variation in hydrocarbon profiles is important for identifying potential vulnerabilities relating to pest ecology and life histories and for developing tools for pest monitoring and management strategies. In this study, we assessed potential sources of variation in CHC profiles in the navel orangeworm Amyelois transitella (Walker) (Lepidoptera: Pyralidae), an economically important pest of nut crops in California. Using coupled gas chromatography-mass spectrometry, we characterized and compared CHC profiles between adults of pyrethroid-resistant (R347) and susceptible (ALMOND) strains. We further compared CHC profiles from adults differing in age (1, 3, 5, and 7 d post-eclosion) and sex. Hydrocarbon profiles comprised 47 different CHCs in detectable quantities that ranged from C_17 to C_43 in chain length and included straight-chain alkanes and a variety of mono-, di-, and tri-methylalkanes. Adults from resistant populations had greater quantities of CHCs in total than those from susceptible strains, but relative quantities of individual components were similar. The six most abundant compounds were n -pentacosane, n -heptacosane, n -nonacosane, n -hentriacontane, 11,25 + 13,23 + 15,21-dimethylpentatriacontane, and 13,23 + 11,25 + 9,17-dimethylheptatriacontane. Post-eclosion, total CHCs increased with adult age, with males producing greater quantities than females at all ages. Our results show that CHC profiles vary depending on age, sex, and strain and suggest that CHC profiles may be useful as biomarkers to differentiate between insecticide- resistant and susceptible populations.

  • author correction factors associated with variation in cuticular hydrocarbon profiles in the navel orangeworm Amyelois transitella lepidoptera pyralidae
    Journal of Chemical Ecology, 2020
    Co-Authors: Esther N. Ngumbi, Jocelyn G. Millar, Lawrence M. Hanks, Andrew V. Suarez, May R Berenbaum
    Abstract:

    The original version of this article unfortunately contained a mistake. When filing the final publication details, we failed to include the following statement in our Acknowledgments paragraph: We thank the Almond Board of California for research funding.

  • Accelerated Development and Toxin Tolerance of the Navel Orangeworm Amyelois transitella (Lepidoptera: Pyralidae) in the Presence of Aspergillus flavus
    Journal of Chemical Ecology, 2018
    Co-Authors: Daniel S Bush, Joel P. Siegel, May R Berenbaum
    Abstract:

    The navel orangeworm ( Amyelois transitella ) and the fungus Aspergillus flavus constitute a facultative mutualism and pest complex in tree nut and fruit orchards in California. The possibility exists that the broad detoxification capabilities of A. flavus benefit its insect associate by metabolizing toxicants, including hostplant phytochemicals and pesticides. We examined this hypothesis by conducting laboratory bioassays to assess growth rates and survivorship of pyrethroid-resistant (R347) and susceptible (CPQ) larval strains on potato dextrose agar diet containing almond meal with and without two furanocoumarins, xanthotoxin and bergapten, found in several hostplants, and with and without two insecticides, bifenthrin and spinetoram, used in almond and pistachio orchards. Additionally, fungi were incubated in liquid diets containing the test chemicals, and extracts of these diets were added to almond potato dextrose agar (PDA) diets and fed to larvae to evaluate the ability of the fungus to metabolize these chemicals. Larvae consuming furanocoumarin-containing diet experienced higher mortality than individuals on unamended diets, but adding A. flavus resulted in up to 61.7% greater survival. Aspergillus flavus in the diet increased development rate > two-fold when furanocoumarins were present, demonstrating fungal enhancement of diet quality. Adding extracts of liquid diets containing xanthotoxin and fungus decreased mortality compared to xanthotoxin alone. On diets containing bifenthrin and spinetoram, however, mortality increased. These results support the hypothesis that A. flavus enhances navel orangeworm performance and contributes to detoxification of xenobiotics. Among practical implications of our findings, this mutualistic association should be considered in designing chemical management strategies for these pests.

  • Impact of agricultural adjuvants on the toxicity of the diamide insecticides chlorantraniliprole and flubendiamide on different life stages of the navel orangeworm (Amyelois transitella)
    Journal of Pest Science, 2018
    Co-Authors: Mark R. Demkovich, Joel P. Siegel, Spencer S. Walse, May R Berenbaum
    Abstract:

    The navel orangeworm ( Amyelois transitella ) (Walker) is a destructive pest of tree nuts in California orchards. Overall demand for these crops and acreage expansions have resulted in significant insecticide applications to reduce A. transitella damage. Despite widespread use in A. transitella insecticide applications, the potential toxicity of adjuvants applied in combination with insecticides remains uncharacterized. In these experiments, five adjuvants (Cohere^®, Dyne-Amic^®, FastStrike^®, Induce^®, Latron B-1956^®), alone and in combination with the diamide insecticides chlorantraniliprole (Altacor^®) and flubendiamide (Belt^®), were assessed for activity against the adults and eggs of A. transitella . Laboratory studies utilized a spray tower for application while field studies used orchard air-blast sprayers. Laboratory exposure of both adults and eggs demonstrated that adjuvant toxicity varied across life stages. In the laboratory, the addition of chlorantraniliprole to adjuvants increased incapacity (dead + moribund). The results for flubendiamide were variable, and only FastStrike had the same high adult toxicity for both diamides. For eggs exposed to these diamides, overall mortality was similar. In field studies, Dyne-Amic and Latron B-1956 were tested and their adult toxicity varied. In contact assays, effects of adjuvants were similar when used with Belt^® and differed when used with Altacor^®. We conclude that the adjuvants for navel orangeworm management are intrinsically toxic to A. transitella in both the laboratory and field. Further studies are needed to attain the toxicity realized in the laboratory in field applications and also to determine whether our findings of adjuvant enhancement of insecticide toxicity are applicable to other insecticide classes.

Joel P. Siegel - One of the best experts on this subject based on the ideXlab platform.

  • Differential regulation of cytochrome P450 genes associated with biosynthesis and detoxification in bifenthrin-resistant populations of navel orangewom (Amyelois transitella).
    'Public Library of Science (PLoS)', 2021
    Co-Authors: Mark R. Demkovich, Joel P. Siegel, Bradley S. Higbee, Bernarda Calla, Esther Ngumbi, May R Berenbaum
    Abstract:

    Pyrethroid resistance was first reported in 2013 for the navel orangeworm, Amyelois transitella, but the genetic underpinnings of pyrethroid resistance are unknown. We investigated the role of cytochrome P450 monooxygenases (P450s) belonging to the CYP3 and CYP4 clans using colonies derived from individuals collected in 2016 from almond orchards in two counties. One colony (ALM) originated from an almond orchard in Madera County with no reported pyrethroid resistance and the second colony (R347) originated from the same Kern County orchard where pyrethroid resistance was first reported. We used high-throughput quantitative real-time PCR (qRT-PCR) analyses of 65 P450s in the CYP3 and CYP4 clans of A. transitella to identify P450s induced by bifenthrin and associated with pyrethroid resistance. Nine P450s were constitutively overexpressed in R347 compared to ALM, including CYP6AE54 (11.7-fold), belonging to a subfamily associated with metabolic pesticide detoxification in Lepidoptera and CYP4G89 (33-fold) belonging to a subfamily associated with cuticular hydrocarbon (CHC) synthesis and resistance via reduced pesticide penetrance. Cuticular hydrocarbons analysis revealed that R347 produced twice as many total CHCs in the egg and adult stages as ALM. Topical toxicity bioassays for R347 determined that egg mortality was reduced at low bifenthrin concentrations and larval mortality was reduced at high concentrations of bifenthrin compared to ALM. Our discovery of both changes in metabolism and production of CHCs for R347 have implications for the possible decreased efficacy of other classes of insecticide used to control this insect. The threat of widespread pyrethroid resistance combined with the potential for cross-resistance to develop through the mechanism of reduced penetrance warrants developing management strategies that facilitate insecticide passage across the cuticle

  • evaluating insecticide coverage and determining its effect on the duration of control for navel orangeworm Amyelois transitella walker lepidoptera pyralidae in california almonds
    Pest Management Science, 2019
    Co-Authors: Joel P. Siegel, Mathew M Strmiska, Spenser S Walse
    Abstract:

    Background Insecticide application is essential to control navel orangeworm (Amyelois transitella) in California almonds (Prunus dulcis), but coverage is challenging. Laboratory and field trials were conducted from 2014 to 2017 to quantify insecticide deposition and duration of control. Results In the laboratory for filter paper, photolysis reduced the contact toxicity of bifenthrin, and its half-life was 6.2 days. For chlorantraniliprole applied in the field, there was 87-94% less insecticide deposited in the almond suture, the most vulnerable part of the nut, than on the hull. For chlorantraniliprole, adjuvant choice (alcohol ethoxylate versus mineral oil) affected both initial insecticide deposition and half-life. Chlorantraniliprole degradation was greater at 6.1 m than at 3 m for both adjuvants assessed, whereas contact mortality was similar at both heights for the alcohol ethoxylate adjuvant. Conclusion The combination of photolysis and differential distribution of insecticide on the nut can account for the variable control observed in the field. This was particularly problematic in the upper canopy and adjuvant choice affected deposition and insecticide degradation. Less than 1% of the insecticide in the tank was deposited on the almond suture. These results demonstrating the fraction of the insecticide in the sprayer tank deposited on the nut target, combined with reduced coverage in the upper canopy are also applicable to the control of A. transitella in pistachio (Pistacia vera) and walnut (Juglans regia) orchards. © 2019 Society of Chemical Industry.

  • evaluating insecticide coverage in almond and pistachio for control of navel orangeworm Amyelois transitella lepidoptera pyralidae
    Pest Management Science, 2019
    Co-Authors: Joel P. Siegel, Franz J A Niederholzer, Mathew M Strmiska, Ken D Giles, Spenser S Walse
    Abstract:

    Background Insecticide application is essential to control navel orangeworm (Amyelois transitella) in California almond and pistachios. Coverage is difficult because of tree height and applicator practices. Studies were conducted to characterize insecticide deposition by both ground and air, and to develop alternatives to the use of water-sensitive cards to assess spray coverage. Results We used almond challenge bioassays to demonstrate that insecticide application failed first in the upper canopy (5.2-6.1 m) when application speed exceeded 2.9 kph. In pistachios, we used filter paper and insecticide extraction from hulls to demonstrate that deposition increased with application volume. Typically, in ground applications, coverage decreased with height, whereas for application by air, coverage was greatest at the top of the canopy (6 m) and decreased as the spray penetrated the canopy. In the best ground applications there was no loss over height. We were able to demonstrate a dose-response relationship for methoxyfenozide using contact toxicity bioassays. Conclusion Coverage was best at or below the recommended speed of 3.2 kph and improved when water volume increased. There was a 50% loss in insecticide efficacy at the height of 4-4.8 m; we suggest that future monitoring concentrate on this portion of the canopy. The best ground application provided uniform deposition throughout the canopy, whereas the applications by air were most effective in the upper canopy. The use of filter paper can provide information for chemical deposition and enable contact toxicity bioassays, whereas water-sensitive paper cannot do this. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

  • Accelerated Development and Toxin Tolerance of the Navel Orangeworm Amyelois transitella (Lepidoptera: Pyralidae) in the Presence of Aspergillus flavus
    Journal of Chemical Ecology, 2018
    Co-Authors: Daniel S Bush, Joel P. Siegel, May R Berenbaum
    Abstract:

    The navel orangeworm ( Amyelois transitella ) and the fungus Aspergillus flavus constitute a facultative mutualism and pest complex in tree nut and fruit orchards in California. The possibility exists that the broad detoxification capabilities of A. flavus benefit its insect associate by metabolizing toxicants, including hostplant phytochemicals and pesticides. We examined this hypothesis by conducting laboratory bioassays to assess growth rates and survivorship of pyrethroid-resistant (R347) and susceptible (CPQ) larval strains on potato dextrose agar diet containing almond meal with and without two furanocoumarins, xanthotoxin and bergapten, found in several hostplants, and with and without two insecticides, bifenthrin and spinetoram, used in almond and pistachio orchards. Additionally, fungi were incubated in liquid diets containing the test chemicals, and extracts of these diets were added to almond potato dextrose agar (PDA) diets and fed to larvae to evaluate the ability of the fungus to metabolize these chemicals. Larvae consuming furanocoumarin-containing diet experienced higher mortality than individuals on unamended diets, but adding A. flavus resulted in up to 61.7% greater survival. Aspergillus flavus in the diet increased development rate > two-fold when furanocoumarins were present, demonstrating fungal enhancement of diet quality. Adding extracts of liquid diets containing xanthotoxin and fungus decreased mortality compared to xanthotoxin alone. On diets containing bifenthrin and spinetoram, however, mortality increased. These results support the hypothesis that A. flavus enhances navel orangeworm performance and contributes to detoxification of xenobiotics. Among practical implications of our findings, this mutualistic association should be considered in designing chemical management strategies for these pests.

  • Impact of agricultural adjuvants on the toxicity of the diamide insecticides chlorantraniliprole and flubendiamide on different life stages of the navel orangeworm (Amyelois transitella)
    Journal of Pest Science, 2018
    Co-Authors: Mark R. Demkovich, Joel P. Siegel, Spencer S. Walse, May R Berenbaum
    Abstract:

    The navel orangeworm ( Amyelois transitella ) (Walker) is a destructive pest of tree nuts in California orchards. Overall demand for these crops and acreage expansions have resulted in significant insecticide applications to reduce A. transitella damage. Despite widespread use in A. transitella insecticide applications, the potential toxicity of adjuvants applied in combination with insecticides remains uncharacterized. In these experiments, five adjuvants (Cohere^®, Dyne-Amic^®, FastStrike^®, Induce^®, Latron B-1956^®), alone and in combination with the diamide insecticides chlorantraniliprole (Altacor^®) and flubendiamide (Belt^®), were assessed for activity against the adults and eggs of A. transitella . Laboratory studies utilized a spray tower for application while field studies used orchard air-blast sprayers. Laboratory exposure of both adults and eggs demonstrated that adjuvant toxicity varied across life stages. In the laboratory, the addition of chlorantraniliprole to adjuvants increased incapacity (dead + moribund). The results for flubendiamide were variable, and only FastStrike had the same high adult toxicity for both diamides. For eggs exposed to these diamides, overall mortality was similar. In field studies, Dyne-Amic and Latron B-1956 were tested and their adult toxicity varied. In contact assays, effects of adjuvants were similar when used with Belt^® and differed when used with Altacor^®. We conclude that the adjuvants for navel orangeworm management are intrinsically toxic to A. transitella in both the laboratory and field. Further studies are needed to attain the toxicity realized in the laboratory in field applications and also to determine whether our findings of adjuvant enhancement of insecticide toxicity are applicable to other insecticide classes.

Juming Tang - One of the best experts on this subject based on the ideXlab platform.

  • heating uniformity and differential heating of insects in almonds associated with radio frequency energy
    Journal of Stored Products Research, 2013
    Co-Authors: Juming Tang, J A Johnson, Shaojin Wang, R P Cavalieri
    Abstract:

    Radio frequency (RF) treatments have potential as alternatives to chemical fumigation for phytosanitary disinfestation treatments in the dried nut industry. To develop effective RF treatment protocols for almonds, it is desirable to determine heating uniformity and the occurrence of RF differential heating of insects. This study compared heating uniformity in almonds (Nonpareil) heated by RF and by forced hot air. A mathematical model suggested a 4.7 and 6.0 � C RF preferential heating of the target pest navel orangeworm (Amyelois transitella [Walker]) over almonds at heating rates of 5 and 10

  • radio frequency disinfestation treatments for dried fruit dielectric properties
    Lwt - Food Science and Technology, 2013
    Co-Authors: Bandar Alfaifi, Juming Tang, Shaojin Wang, Barbara Rasco, Shyam S Sablani, Yang Jiao
    Abstract:

    Abstract Phytosanitary/quarantine regulations for many countries require that certain dried fruit be disinfected prior to export; however, current technologies involve the use of toxic chemicals and conventional thermal methods are either undesirable or cause loss of volatile components, browning and texture change. Newer physical methods including dielectric heating have been considered, but information on dielectric properties of dried fruits is lacking. Because the loss factor of insect pests, Indian meal moth ( Plodia interpunctella ) and navel orangeworm ( Amyelois transitella ), is several times (26–36) greater than that of dried fruits, RF treatment in particular has great potential for insect disinfection. In this study, the dielectric properties of raisins, dates, apricots, figs, and prunes with water contents of 15–30.2 g/100 g, were determined between 10 and 1800 MHz over a range of 20–60 °C. The dielectric constant and loss factor of all samples decreased with increasing frequency, but increased with increasing temperature at each frequency. The loss factor of all samples increased with increasing water contents/water activity (0.5–0.7). The penetration depths (dps) of RF energy in all samples decreased with increasing frequency and temperature. The deep dp (28.4–103.7 cm) at 27 MHz indicates the potential for developing continuous and large-scale RF treatments for postharvest insect control in dried fruits.

  • determining thermotolerance of fifth instar cydia pomonella l lepidoptera tortricidae and Amyelois transitella walker lepidoptera pyralidae by three different methods
    Journal of Stored Products Research, 2009
    Co-Authors: Shaojin Wang, J A Johnson, James D Hansen, Juming Tang
    Abstract:

    Thermotolerances of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), and navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), were determined using two waterimmersion methods and one dry-heat method. The two water-immersion methods were: 1) directly immersing screen tubes containing test insects in hot water (direct immersion method) and 2) immersing in hot water solid copper tubes containing insects submerged in tap water (tube immersion method). The dry heating method involved heating insects in computer-controlled heating blocks (heating block system, or HBS). Each test insect was treated at three temperature-time combinations and exposures were adjusted so that each method received the same equivalent accumulated lethal time. In five of the six tests, the HBS provided the lowest mean insect mortality among the three methods, although no statistically significant differences were observed between the direct immersion and the HBS methods. The mean insect mortality obtained with the tube immersion method was significantly higher than that from the direct immersion method and the HBS in four and three of the six temperature-time combinations, respectively. When compared with the two water-immersion methods, the HBS method yielded lower mortality data with less variation at the same mortality level, resulting in more conservative treatment recommendations.

  • heating condition effects on thermal resistance of fifth instar Amyelois transitella walker lepidoptera pyralidae
    Journal of Stored Products Research, 2005
    Co-Authors: Shaojin Wang, Juming Tang, J A Johnson, X Yin
    Abstract:

    Abstract Successful development of a thermal treatment protocol depends on reliable information on fundamental thermal death kinetics of targeted insects under different heating conditions. The effects of heating rates (1, 10, and 15 °C min −1 ), pre-treatment conditioning (30 °C+6 h), and the difference between long-term laboratory cultures and recently isolated cultures on thermal mortality of fifth-instar navel orangeworm, Amyelois transitella (Walker), were studied using a heating block system. There was no significant difference in insect mortality resulting from heating rates of 10 and 15 °C min −1 . Temperature control at 1 °C min −1 was more uniform than for the other heating rates, resulting in reduced variability for insect mortality. The mean mortality at the heating rate of 1 °C min −1 was significantly lower than for the two faster heating rates only at 48 °C+30 min. The pre-treatment conditioning of fifth-instar Amyelois transitella enhanced their thermotolerance only at certain temperature–time combinations. Fifth-instars from long-term laboratory and recently isolated cultures were equally susceptible to elevated temperatures. Therefore, thermal death kinetic information obtained from the long-term laboratory cultures can be used to develop thermal protocols against field pests.

  • Application of radio frequency treatments to control insects in in-shell walnuts
    Postharvest Biology and Technology, 2004
    Co-Authors: Elizabeth J. Mitcham, Rebecca H. Veltman, Xuqiao Feng, Judy A. Johnson, Tiffanie Simpson, E Castro, William V. Biasi, Juming Tang
    Abstract:

    Codling moth (Cydia pomonella [L.]), navel orangeworm (Amyelois transitella [Walker]), and Indianmeal moth (Plodia interpunctella [Hubner]) are common insect pests in walnuts (Juglans regia [L.]). Currently, exported in-shell walnuts are disinfested using methyl bromide fumigation. Restrictions on methyl bromide use have increased interest in developing alternative postharvest treatments. Radio frequency (RF) heating is such an alternative. Our tests have shown that heating walnuts with radio frequency energy to temperatures lethal to these important insect pests has no negative effects on walnut quality, and may even reduce the susceptibility of walnuts to becoming rancid in storage. Radio frequency treatments provided acceptable rates of heating (5–6 ◦ C min −1 ) for in-shell walnuts to lethal temperatures. Heating walnuts to 55 ◦ C or higher resulted in 100% mortality of fifth instar navel orangeworm, which is the most resistant of the three insect pests. Moisture content of walnuts is an important factor affecting heating rates during radio frequency treatments. The relationship between average moisture content and average heating rate was linear, and the variability in moisture content and heating rates was higher with a higher average moisture content. Radio frequency treatments reduce the moisture content of walnuts. A combined system of radio frequency heating with hot air has the potential to accelerate or even replace batch drying of walnuts in the future. © 2004 Elsevier B.V. All rights reserved.

Walter S Leal - One of the best experts on this subject based on the ideXlab platform.

  • alternative splicing produces two transcripts encoding female biased pheromone subfamily receptors in the navel orangeworm Amyelois transitella
    Frontiers in Ecology and Evolution, 2015
    Co-Authors: Stephen F Garczynski, Walter S Leal
    Abstract:

    Insect odorant receptors are key sensors of environmental odors and members of the lepidopteran pheromone receptor subfamily are thought to play important roles in mate finding by recognizing sex pheromones. Much research has been done to identify putative pheromone receptors in lepidopteran males, but little attention has been given to female counterparts. In this study, degenerate oligonucleotide primers designed against a conserved amino acid region in the C-terminus of lepidopteran pheromone receptors were used in 3’ RACE reactions to identify candidate pheromone receptors expressed in the antennae of female navel orangeworm. Two near full-length transcripts of 1469 nt and 1302 nt encoding the complete open reading frames for proteins of 446 and 425 amino acids, respectively, were identified. Based on BLAST homology and phylogenetic analyses, the putative proteins encoded by these transcripts are members of the lepidopteran pheromone receptor subfamily. Characterization of these transcripts indicates that they are alternatively spliced products of a single gene. Tissue expression studies indicate that the transcripts are female-biased with detection mainly in female antennae. To the best of our knowledge, these transcripts represent the first detection of alternatively spliced female-biased members of the lepidopteran pheromone receptor subfamily.

  • crystallographic observation of ph induced conformational changes in the Amyelois transitella pheromone binding protein atrapbp1
    PLOS ONE, 2013
    Co-Authors: Eric Di Luccio, Walter S Leal, Yuko Ishida, David K Wilson
    Abstract:

    The navel orangeworm, Amyelois transitella is a major agricultural pest causing large losses in a variety of tree crops. Control of this insect pest may be achieved by interfering with olfactory pathways to block detection of female-produced sex pheromones and consequently, disrupt mating. The first component of this pathway is the pheromone-binding protein AtraPBP1, which recognizes the pheromone and presents it to the odorant receptor housed in a sensory neuron of the male antennae. Release of the ligand depends on a pH-induced conformational change associated with the acidity of the membrane surface. To characterize this conformational change and to understand how pheromones bind, we have determined the high resolution crystal structures of AtraPBP1 in complex with two main constituents of the sex pheromone, i.e., (11Z,13Z)-hexadecadienal and (11Z,13Z)-hexadecadienol. Comparison with the structure of the unliganded form demonstrates a large ∼90° movement of the C-terminal helix which is observed in other pheromone- or odorant-binding proteins accompanied by an unpredicted 37° displacement of the N-terminal helix. Molecular dynamic trajectories suggest that the conformational change of the α1 helix facilitates the movement of the C-terminal helix.

  • Secondary structure and sequence alignment of some of the structurally characterized pheromone-binding proteins.
    2013
    Co-Authors: Eric Di Luccio, Walter S Leal, Yuko Ishida, David K Wilson
    Abstract:

    AtraPBP1 (Amyelois transitella); BmorPBP (Bombyx mori); AgamOBP1 (Anopheles gambiae); LUSH/DmelOBP76a (Drosophila melanogaster); AmelASP1(Apis mellifera); LmadPBP (Leucophaea maderae). Structurally conserved cysteine residues are boxed in red. Residues involved in hydrophobic contacts with the pheromones (AtraPBP1) are shown in blue. Residues engaged in hydrogen bonding with the ligands are colored in green. Uniprot accession IDs are as follow: D0E9M1 (AtraPBP1); P34174 (BmorPBP); Q8I8T0 (AgamOBP1); O02372 (DmelOBP76a/LUSH); Q9U9J6 (AmelASP1); Q8MTC1 (LmaPBP).

  • nmr structure of navel orangeworm moth pheromone binding protein atrapbp1 implications for ph sensitive pheromone detection
    Biochemistry, 2010
    Co-Authors: Josep Rayo, Walter S Leal, Yuko Ishida, James B Ames
    Abstract:

    The navel orangeworm, Amyelois transitella (Walker), is an agricultural insect pest that can be controlled by disrupting male−female communication with sex pheromones, a technique known as mating disruption. Insect pheromone-binding proteins (PBPs) provide fast transport of hydrophobic pheromones through the aqueous sensillar lymph and promote sensitive delivery of pheromones to receptors. Here we present the three-dimensional structure of a PBP from A. transitella (AtraPBP1) in solution at pH 4.5 determined by nuclear magnetic resonance (NMR) spectroscopy. Pulsed-field gradient NMR diffusion experiments, multiangle light scattering, and 15N NMR relaxation analysis indicate that AtraPBP1 forms a stable monomer in solution at pH 4.5 in contrast to forming mostly dimers at pH 7. The NMR structure of AtraPBP1 at pH 4.5 contains seven α-helices (α1, L8−L23; α2, D27−F36; α3, R46−V62; α4, A73−M78; α5, D84−S100; α6, R107−L125; α7, M131−E141) that adopt an overall main-chain fold similar to that of PBPs found in ...

  • olfactory proteins mediating chemical communication in the navel orangeworm moth Amyelois transitella
    PLOS ONE, 2009
    Co-Authors: Walter S Leal, Yuko Ishida, Josep Rayo, Julien Pelletier, James B Ames
    Abstract:

    Background The navel orangeworm, Amyelois transitella Walker (Lepidoptera: Pyralidae), is the most serious insect pest of almonds and pistachios in California for which environmentally friendly alternative methods of control — like pheromone-based approaches — are highly desirable. Some constituents of the sex pheromone are unstable and could be replaced with parapheromones, which may be designed on the basis of molecular interaction of pheromones and pheromone-detecting olfactory proteins. Methodology By analyzing extracts from olfactory and non-olfactory tissues, we identified putative olfactory proteins, obtained their N-terminal amino acid sequences by Edman degradation, and used degenerate primers to clone the corresponding cDNAs by SMART RACE. Additionally, we used degenerate primers based on conserved sequences of known proteins to fish out other candidate olfactory genes. We expressed the gene encoding a newly identified pheromone-binding protein, which was analyzed by circular dichroism, fluorescence, and nuclear magnetic resonance, and used in a binding assay to assess affinity to pheromone components. Conclusion We have cloned nine cDNAs encoding olfactory proteins from the navel orangeworm, including two pheromone-binding proteins, two general odorant-binding proteins, one chemosensory protein, one glutathione S-transferase, one antennal binding protein X, one sensory neuron membrane protein, and one odorant receptor. Of these, AtraPBP1 is highly enriched in male antennae. Fluorescence, CD and NMR studies suggest a dramatic pH-dependent conformational change, with high affinity to pheromone constituents at neutral pH and no binding at low pH.

Shaojin Wang - One of the best experts on this subject based on the ideXlab platform.

  • heating uniformity and differential heating of insects in almonds associated with radio frequency energy
    Journal of Stored Products Research, 2013
    Co-Authors: Juming Tang, J A Johnson, Shaojin Wang, R P Cavalieri
    Abstract:

    Radio frequency (RF) treatments have potential as alternatives to chemical fumigation for phytosanitary disinfestation treatments in the dried nut industry. To develop effective RF treatment protocols for almonds, it is desirable to determine heating uniformity and the occurrence of RF differential heating of insects. This study compared heating uniformity in almonds (Nonpareil) heated by RF and by forced hot air. A mathematical model suggested a 4.7 and 6.0 � C RF preferential heating of the target pest navel orangeworm (Amyelois transitella [Walker]) over almonds at heating rates of 5 and 10

  • radio frequency disinfestation treatments for dried fruit dielectric properties
    Lwt - Food Science and Technology, 2013
    Co-Authors: Bandar Alfaifi, Juming Tang, Shaojin Wang, Barbara Rasco, Shyam S Sablani, Yang Jiao
    Abstract:

    Abstract Phytosanitary/quarantine regulations for many countries require that certain dried fruit be disinfected prior to export; however, current technologies involve the use of toxic chemicals and conventional thermal methods are either undesirable or cause loss of volatile components, browning and texture change. Newer physical methods including dielectric heating have been considered, but information on dielectric properties of dried fruits is lacking. Because the loss factor of insect pests, Indian meal moth ( Plodia interpunctella ) and navel orangeworm ( Amyelois transitella ), is several times (26–36) greater than that of dried fruits, RF treatment in particular has great potential for insect disinfection. In this study, the dielectric properties of raisins, dates, apricots, figs, and prunes with water contents of 15–30.2 g/100 g, were determined between 10 and 1800 MHz over a range of 20–60 °C. The dielectric constant and loss factor of all samples decreased with increasing frequency, but increased with increasing temperature at each frequency. The loss factor of all samples increased with increasing water contents/water activity (0.5–0.7). The penetration depths (dps) of RF energy in all samples decreased with increasing frequency and temperature. The deep dp (28.4–103.7 cm) at 27 MHz indicates the potential for developing continuous and large-scale RF treatments for postharvest insect control in dried fruits.

  • determining thermotolerance of fifth instar cydia pomonella l lepidoptera tortricidae and Amyelois transitella walker lepidoptera pyralidae by three different methods
    Journal of Stored Products Research, 2009
    Co-Authors: Shaojin Wang, J A Johnson, James D Hansen, Juming Tang
    Abstract:

    Thermotolerances of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), and navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), were determined using two waterimmersion methods and one dry-heat method. The two water-immersion methods were: 1) directly immersing screen tubes containing test insects in hot water (direct immersion method) and 2) immersing in hot water solid copper tubes containing insects submerged in tap water (tube immersion method). The dry heating method involved heating insects in computer-controlled heating blocks (heating block system, or HBS). Each test insect was treated at three temperature-time combinations and exposures were adjusted so that each method received the same equivalent accumulated lethal time. In five of the six tests, the HBS provided the lowest mean insect mortality among the three methods, although no statistically significant differences were observed between the direct immersion and the HBS methods. The mean insect mortality obtained with the tube immersion method was significantly higher than that from the direct immersion method and the HBS in four and three of the six temperature-time combinations, respectively. When compared with the two water-immersion methods, the HBS method yielded lower mortality data with less variation at the same mortality level, resulting in more conservative treatment recommendations.

  • heating condition effects on thermal resistance of fifth instar Amyelois transitella walker lepidoptera pyralidae
    Journal of Stored Products Research, 2005
    Co-Authors: Shaojin Wang, Juming Tang, J A Johnson, X Yin
    Abstract:

    Abstract Successful development of a thermal treatment protocol depends on reliable information on fundamental thermal death kinetics of targeted insects under different heating conditions. The effects of heating rates (1, 10, and 15 °C min −1 ), pre-treatment conditioning (30 °C+6 h), and the difference between long-term laboratory cultures and recently isolated cultures on thermal mortality of fifth-instar navel orangeworm, Amyelois transitella (Walker), were studied using a heating block system. There was no significant difference in insect mortality resulting from heating rates of 10 and 15 °C min −1 . Temperature control at 1 °C min −1 was more uniform than for the other heating rates, resulting in reduced variability for insect mortality. The mean mortality at the heating rate of 1 °C min −1 was significantly lower than for the two faster heating rates only at 48 °C+30 min. The pre-treatment conditioning of fifth-instar Amyelois transitella enhanced their thermotolerance only at certain temperature–time combinations. Fifth-instars from long-term laboratory and recently isolated cultures were equally susceptible to elevated temperatures. Therefore, thermal death kinetic information obtained from the long-term laboratory cultures can be used to develop thermal protocols against field pests.

  • thermal death kinetics of fifth instar plodia interpunctella lepidoptera pyralidae
    Journal of Economic Entomology, 2003
    Co-Authors: J A Johnson, Shaojin Wang, Juming Tang
    Abstract:

    Heat treatments have been suggested as alternatives to chemical fumigants for control of postharvest insects in dried fruits and nuts. Conventional forced hot air treatments heat product too slowly to be practical, but radio frequency treatments are capable of more rapid product heating. While developing radio frequency heat treatments for dried fruits and nuts, the heat tolerance of nondiapausing and diapausing fifth-instar larvae of the Indianmeal moth, Plodia interpunctella (Hubner), was determined using a heating block system developed by Washington State University. Both a 0.5th order kinetic model and a classical empirical model were used to estimate lethal exposure times for temperatures of 44–52°C for nondiapausing fifth-instar larvae. We obtained 95% mortality at exposures suitable for practical radio frequency treatments (≤5 min) with temperatures of 50 and 52°C. Diapausing larvae were significantly more tolerant than nondiapausing larvae at the lowest treatment temperature and shortest exposure, but differences were not significant at more extreme temperature-time combinations. Previous studies showed that fifth-instar larvae of the navel orangeworm, Amyelois transitella (Walker), were more heat tolerant than either diapausing or nondiapausing Indianmeal moth larvae. Consequently, efficacious treatments for navel orangeworm would also control Indianmeal moth.