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Christer Lofstedt - One of the best experts on this subject based on the ideXlab platform.

  • Ionotropic receptors in the turnip moth Agrotis Segetum respond to repellent medium-chain fatty acids
    2021
    Co-Authors: Xiaoqing Hou, Dan-dan Zhang, Powell D, Hong-lei Wang, Martin Andersson, Christer Lofstedt
    Abstract:

    In insects, airborne chemical signals are mainly detected by two receptor families, odorant receptors (ORs) and ionotropic receptors (IRs). Functions of ORs have been intensively investigated in Diptera and Lepidoptera, while the functions and evolution of the more ancient IR family remain largely unexplored beyond Diptera. Here, we identified a repertoire of 26 IRs from transcriptomes of female and male antennae, and ovipositors in the moth Agrotis Segetum. We observed that a large clade formed by IR75p and IR75q expansions is closely related to the acid-sensing IRs identified in Diptera. We functionally assayed each of the five AsegIRs from this clade using Xenopus oocytes and found that two receptors responded to the tested ligands. AsegIR75p.1 responded to several compounds but hexanoic acid was revealed to be the primary ligand, and AsegIR75q.2 responded primarily to octanoic acid, and less so to nonanoic acid. It has been reported that the C6-C10 medium-chain fatty acids repel various insects including many drosophilids and mosquitos. Our GC-EAD recordings showed that C6-C10 medium-chain fatty acids elicited antennal responses of both sexes of A. Segetum, while only octanoic acid had repellent effect to the moths in a behavioural assay. In addition, using fluorescence in situ hybridization, we demonstrated that AsegIR75q.2 and its co-receptor AsegIR8a are not located in coeloconic sensilla as found in Drosophila, but in basiconic or trichoid sensilla. These functional data in combination with our phylogenetic analysis suggest that subfunctionalization of the acid-sensing IRs after gene duplication plays an important role in the evolution of ligand specificities of the acid-sensing IRs in Lepidoptera.

  • Functional Evolution of a Multigene Family: Orthologous and Paralogous Pheromone Receptor Genes in the Turnip Moth, Agrotis Segetum
    2016
    Co-Authors: Dan-dan Zhang, Christer Lofstedt
    Abstract:

    Lepidopteran pheromone receptors (PRs), for which orthologies are evident among closely related species, provide an intriguing example of gene family evolution in terms of how new functions may arise. However, only a limited number of PRs have been functionally characterized so far and thus evolutionary scenarios suffer from elements of speculation. In this study we investigated the turnip moth Agrotis Segetum, in which female moths produce a mixture of chemically related pheromone components that elicit specific responses from receptor cells on male antennae. We cloned nine A. Segetum PR genes and the Orco gene by degenerate primer based RT-PCR. The nine PR genes, named as AsegOR1 and AsegOR3-10, fall into four distinct orthologous clusters of known lepidopteran PRs, of which one contains six paralogues. The paralogues are under relaxed selective pressure, contrasting with the purifying selection on other clusters. We identified the receptors AsegOR9, AsegOR4 and AsegOR5, specific for the respective homologous pheromone components (Z)-5-decenyl, (Z)-7-dodecenyl and (Z)-9-tetradecenyl acetates, by two-electrode voltage clamp recording from Xenopus laevis oocytes co-expressing Orco and each PR candidate. These receptors occur in three different orthologous clusters. We also found that the six paralogues with high sequence similarity vary dramatically in ligand selectivity and sensitivity. Different from AsegOR9, AsegOR6 showed a relatively large response to the behavioural antagonist (Z)-5-decenol, and a small response to (Z)-5-deceny

  • analysis of the Agrotis Segetum pheromone gland transcriptome in the light of sex pheromone biosynthesis
    BMC Genomics, 2015
    Co-Authors: Baojian Ding, Christer Lofstedt
    Abstract:

    Moths rely heavily on pheromone communication for mate finding. The pheromone components of most moths are modified from the products of normal fatty acid metabolism by a set of tissue-specific enzymes. The turnip moth, Agrotis Segetum uses a series of homologous fatty-alcohol acetate esters ((Z)-5-decenyl, (Z)-7-dodecenyl, and (Z)-9 tetradecenyl acetate) as its sex pheromone components. The ratio of the components differs between populations, making this species an interesting subject for studies of the enzymes involved in the biosynthetic pathway and their influence on sex pheromone variation. Illumina sequencing and comparative analysis of the transcriptomes of the pheromone gland and abdominal epidermal tissue, enabled us to identify genes coding for putative key enzymes involved in the pheromone biosynthetic pathway, such as fatty acid synthase, β-oxidation enzymes, fatty-acyl desaturases (FAD), fatty-acyl reductases (FAR), and acetyltransferases. We functionally assayed the previously identified ∆11-desaturase [GenBank: ES583599, JX679209] and FAR [GenBank: JX679210] and candidate acetyltransferases (34 genes) by heterologous expression in yeast. The functional assay confirmed that the ∆11-desaturase interacts with palmitate and produces (Z)-11-hexadecenoate, which is the common unsaturated precursor of three homologous pheromone component acetates produced by subsequent chain-shortening, reduction and acetylation. Much lower, but still visible, activity on 14C and 12C saturated acids may account for minor pheromone compounds previously observed in the pheromone gland. The FAR characterized can operate on various unsaturated fatty acids that are the immediate acyl precursors of the different A. Segetum pheromone components. None of the putative acetyltransferases that we expressed heterologously did acetylate any of the fatty alcohols tested as substrates. The massive sequencing technology generates enormous amounts of candidate genes potentially involved in pheromone biosynthesis but testing their function by heterologous expression or gene silencing is a bottleneck. We confirmed the function of a previously identified desaturase gene and a fatty-acyl reductase gene by heterologous expression, but the acetyltransferase postulated to be involved in pheromone biosynthesis remains illusive, in spite of 34 candidates being assayed. We also generated lists of gene candidates that may be useful for characterizing the acetyl-CoA carboxylase, fatty acid synthetase and β-oxidation enzymes.

  • functional evolution of a multigene family orthologous and paralogous pheromone receptor genes in the turnip moth Agrotis Segetum
    PLOS ONE, 2013
    Co-Authors: Dan-dan Zhang, Christer Lofstedt
    Abstract:

    Lepidopteran pheromone receptors (PRs), for which orthologies are evident among closely related species, provide an intriguing example of gene family evolution in terms of how new functions may arise. However, only a limited number of PRs have been functionally characterized so far and thus evolutionary scenarios suffer from elements of speculation. In this study we investigated the turnip moth Agrotis Segetum, in which female moths produce a mixture of chemically related pheromone components that elicit specific responses from receptor cells on male antennae. We cloned nine A. Segetum PR genes and the Orco gene by degenerate primer based RT-PCR. The nine PR genes, named as AsegOR1 and AsegOR3-10, fall into four distinct orthologous clusters of known lepidopteran PRs, of which one contains six paralogues. The paralogues are under relaxed selective pressure, contrasting with the purifying selection on other clusters. We identified the receptors AsegOR9, AsegOR4 and AsegOR5, specific for the respective homologous pheromone components (Z)-5-decenyl, (Z)-7-dodecenyl and (Z)-9-tetradecenyl acetates, by two-electrode voltage clamp recording from Xenopus laevis oocytes co-expressing Orco and each PR candidate. These receptors occur in three different orthologous clusters. We also found that the six paralogues with high sequence similarity vary dramatically in ligand selectivity and sensitivity. Different from AsegOR9, AsegOR6 showed a relatively large response to the behavioural antagonist (Z)-5-decenol, and a small response to (Z)-5-decenyl acetate. AsegOR1 was broadly tuned, but most responsive to (Z)-5-decenyl acetate, (Z)-7-dodecenyl acetate and the behavioural antagonist (Z)-8-dodecenyl acetate. AsegOR8 and AsegOR7, which differ from AsegOR6 and AsegOR1 by 7 and 10 aa respectively, showed much lower sensitivities. AsegOR10 showed only small responses to all the tested compounds. These results suggest that new receptors arise through gene duplication, and relaxed evolutionary constraints or positive selection among paralogues allow functional divergence to occur in spite of purifying selection being the norm.

  • global transcriptional analysis of pheromone biosynthesis related genes in the female turnip moth Agrotis Segetum noctuidae using a custom made cdna microarray
    Insect Biochemistry and Molecular Biology, 2009
    Co-Authors: Maria Strandh, Tomas Johansson, Christer Lofstedt
    Abstract:

    Using a custom-made cDNA microarray, global transcriptional analyses were conducted to identify genes differentially regulated in the pheromone gland as compared to the remaining insect tissue of the moth Agrotis Segetum (Noctuidae). A two-fold or larger difference in relative expression levels was found for 227 of 864 genes investigated comparing the two tissues. Unexpectedly, an antennal binding protein homologue, containing a pheromone-binding/general odorant-binding protein PFAM domain, was expressed at a 56-fold higher level in the pheromone gland. Relatively higher expression levels in the pheromone gland were also found for other gene representatives putatively encoding odorant-binding proteins and chemosensory proteins, as well as a number of gene representatives putatively encoding proteins involved in juvenile hormone interactions. The largest relative up-regulation (84-fold) in the pheromone gland was found for a gene encoding a Delta11-desaturase homologue implicated in desaturation of pheromone precursors. For three gene representatives, the expression patterns were independently verified by quantitative real-time PCR (qPCR). Additionally the expression pattern in the pheromone gland for the Delta11-desaturase homologue was shown by qPCR to follow the previously known pattern of pheromone production in female A. Segetum, both with respect to age and circadian rhythm, whereas the expression of a Delta9-desaturase and a chemosensory protein homologue did not share this pattern.

Bill S Hansson - One of the best experts on this subject based on the ideXlab platform.

  • responses in highly selective sensory neurons to blends of pheromone components in the moth Agrotis Segetum
    Journal of Insect Physiology, 2002
    Co-Authors: Mikael A Carlsson, Bill S Hansson
    Abstract:

    Pheromone detecting sensory neurons in moths are known to be highly sensitive and selective. Female-emitted sexual pheromones are normally mixtures of a few to several components. However, not much is known about how receptor neurons respond to blends of compounds. In the present study we investigated how four physiological types of pheromone component-selective neurons responded to binary mixtures or to the complete blend in the turnip moth Agrotis Segetum. We found that responses to mixtures only rarely differed from that to the excitatory component alone. The mixture interactions were exclusively suppressive and occurred only at high concentrations. Therefore we conclude that the, in A. Segetum, commonly observed mixture interactions observed in higher brain centra are mainly the result of central nervous processing and that information about the pheromone components reaches the antennal lobes virtually unaltered. In addition, we found a physiological type of receptor neuron, responding selectively to one of the female-emitted pheromone components, that has previously not been observed in the Swedish population.

  • comparative study of pheromone production and response in swedish and zimbabwean populations of turnip moth Agrotis Segetum
    Journal of Chemical Ecology, 1999
    Co-Authors: C B Cottrell, Bill S Hansson, Christer Lofstedt
    Abstract:

    Analysis of female sex pheromone gland extracts of the turnip moth (or common cutworm), Agrotis Segetum, from Zimbabwe revealed three compounds previously identified as sex pheromone components in the Swedish population, namely (Z)-5-decenyl acetate (Z5–10:OAc), (Z)-7-dodecenyl acetate (Z7–12:OAc), and (Z)-9-tetradecenyl acetate (Z9–14:OAc). However, the proportions from the Zimbabwean population (1:0.25:0.03) differ from those in the Swedish population (1:5:2.5). In addition, gas chromatography–mass spectrometric (GC-MS) analysis of the Zimbabwean female gland extracts revealed a trace of (Z)-5-dodecenyl acetate (Z5–12:OAc). This compound has recently been identified as a fourth sex pheromone component for the Swedish population. Single-sensillum recordings from both Zimbabwean and Swedish populations showed the presence of two types of antennal receptors responding to either Z5–10:OAc or Z7–12:OAc. In Zimbabwean males the Z7–12:OAc receptor neuron appeared to be confined to the basal and medial thirds of the antennal branches, while in Swedish males it was distributed along the entire antennal branch. Dose–response curves of Z5–10:OAc or Z7–12:OAc specific receptor neurons from males of both populations showed similar response profiles, but the neurons of the Zimbabwean population showed higher maximal responses. In flight tunnel tests with Zimbabwean males, the three-component Zimbabwean blend of Z5–10:OAc, Z7–12:OAc and Z9–14:OAc elicited significantly greater responses than the Swedish blend, but not significantly greater than pheromone glands from calling Zimbabwean females. (Z)-5-decenol (Z5–10:OH), a constituent of gland extracts, exerted an antagonistic effect in the flight tunnel. In field tests conducted in Sweden, local males were preferentially attracted to local females, while in Zimbabwe preferential attraction to local females was less pronounced. Local response to the Swedish and Zimbabwean synthetic four-component blends mirrored the responses to the local females. Zimbabwean males are much more strongly attracted to Z5–10:OAc alone than are Swedish males and the high concentrations of Z7–12:OAc and/or Z9–14:OAc present in the Swedish blend reduced attraction of Zimbabwean males. This reduced attraction appears to be counteracted by the trace amounts of Z5–12:OAc found in the Swedish four-component blend. Addition of Z5–12:OAc to the three-component Zimbabwean blend did not, however, significantly increase the trap catches of Zimbabwean males.

  • discrimination among pheromone component blends by interneurons in male antennal lobes of two populations of the turnip moth Agrotis Segetum
    Proceedings of the National Academy of Sciences of the United States of America, 1996
    Co-Authors: Sylvia Anton, Christer Lofstedt, Bill S Hansson
    Abstract:

    A difference in female pheromone production and male behavioral response has previously been found in two populations of the turnip moth, Agrotis Segetum, originating from Sweden and Zimbabwe, respectively. In this study, we investigated the pheromone response of antennal lobe interneurons of males of the two populations by intracellular recordings, stimulating with single pheromone components and various inter- and intra-populational pheromone blends. Three major physiological types of antennal lobe neurons were established in the two populations according to their responses to different stimuli. One type responded broadly to almost all the stimuli tested. The second type responded selectively to some of the single components and blends. The third type did not respond to any single components but did respond to certain blends. Furthermore, some neurons of the second and third type recognized strain specific differences in ratios between pheromone components. Both projection neurons and local interneurons were found among these three types. Two pheromone responding bilateral projection neurons are reported for the first time in this paper.

  • electrophysiological and behavioural evidence for a fourth sex pheromone component in the turnip moth Agrotis Segetum
    Physiological Entomology, 1995
    Co-Authors: Bill S Hansson, Christer Lofstedt
    Abstract:

    Abstract. In addition to the pheromone components (Z)‐5‐decenyl, (Z)‐7‐dodecenyl and (Z)‐9‐tetradecenyl acetate (Z5‐10:OAc, Z7‐12:OAc and Z9‐14:OAc), it has previously been shown that the sex pheromone gland of the turnip moth, Agrotis Segetum (Lepidoptera: Noctuidae Schiff) contains 10:OAc, 12:OAc, Z5‐12:OAc, Z9‐12:OAc, 11–12:OAc, Z5‐14:OAc, Z7‐14:OAc and Z11‐16:OAc. To find out whether any of these additional compounds is involved in the sex pheromone communication in A. Segetum, a comprehensive electro‐physiological and behavioural investigation was conducted. Single‐sensillum recordings on male antennae revealed three subtypes of sensilla among the previously so‐called Z5‐10:OAc sensilla. One subtype was identified having one receptor neurone (A) that responded to Z5‐10:OAc with a large spike amplitude and another neurone (B) that responded to (Z)‐5‐decenol (Z5‐10:OH) with a small spike amplitude. In another subtype the B neurone responded to Z5‐12:OAc and sometimes also to 27‐12:OAc and 10:OAc, in addition to responding to Z5‐10:OH. In a third subtype the A neurone responded to all acetates identified from the female pheromone gland, whereas the small spike amplitude neurone was tuned to Z5‐10:OH. A flight tunnel assay showed that blends composed of nine, eight or seven compounds were equivalent to the previously identified three‐component pheromone blend in eliciting male behavioural responses. In field trapping tests, blends of eleven, nine or seven compounds did, however, catch significantly more moths than the three‐component blend. Further assays showed that only 25‐ 12:OAc could significantly increase the catch numbers when added to the three‐component blend, and thus qualified as a fourth pheromone component in A. segerum. The behavioural significance of additional female‐produced acetates — for which males possess antennal receptors — is suggested, but may be impossible to confirm because of ‘diminishing returns’ when trying to refine a multicomponent pheromone further. (Less)

  • Electrophysiological and behavioral responses of turnip moth males,Agrotis Segetum to fluorinated pheromone analogs
    Journal of Chemical Ecology, 1993
    Co-Authors: Wu Wenqi, Tommy Liljefors, Bill S Hansson, Christer Lofstedt, Marie Bengtsson, Glenn D. Prestwich, Wei-chuan Sun, Mats Svensson
    Abstract:

    The electrophysiological and behavioral responses of male Agrotis Segetum to fluorinated analogs of (Z)-5-decenyl acetate (Z5-10∶OAc) were investigated. The single sensillum recordings showed that 4,4-difluoro-(Z)-5-decenyl acetate (4,4-F2), 7,7-difluoro-(Z)-5-decenyl acetate (7,7-F2), 10,10,10-trifluoro-(Z)-5-decenyl acetate (10,10,10-F3) and 7,7,8,8-tetrafluoro-(Z)-5-decenyl acetate (7,7,8,8-F4) were each 100-fold less active than the natural Z5-10 ∶ OAc, whereas the 7,7,8,8,9,9,10,10,10-nonafluoro-(Z)-5-decenyl acetate (F9) analog was essentially inactive. A mixture of Z5-10 ∶ OAc, Z7-12 ∶ OAc, and Z9-14 ∶ OAc on a filter paper dispenser was as attractive as female gland extracts when tested in a flight tunnel. With Z5-10∶OAc omitted, the two-component mixture elicited a significantly lower male response. Four analogs, 7,7-F2, 10,10,10-F3, 7,7,8,8-F4, and F9, were added separately to the two-component mixture to replace Z5-10∶OAc. The responses elicited by the mixtures containing the 7,7-F2, 10,10,10-F3, and 7,7,8,8-F4 analogs did not differ significantly from that of the natural three-component mixture and the two-component mixture, whereas the mixture containing F9 elicited a significantly lower male response, as low as the response to the two-component mixture. In a field test the mixtures containing 10,10,10-F3 and 7,7,8,8-F4 were significantly more active than the two-component mixture, but still less active than the natural three-component mixture. It appears that field tests provided greater discrimination among pheromone analogs in assessing their behavioral activity than the flight-tunnel test did. Structure-activity analyses demonstrate the importance of the lipophilic interaction between the terminal alkyl chain and the receptor site for the activity of the stimulus. The lipophobicity of the fluorinated analogs impedes a productive receptor interaction.

Johannes A. Jehle - One of the best experts on this subject based on the ideXlab platform.

  • Agrotis Segetum nucleopolyhedrovirus but not Agrotis Segetum granulovirus replicate in AiE1611T cell line of Agrotisipsilon.
    Journal of invertebrate pathology, 2017
    Co-Authors: Gianpiero Gueli Alletti, Eric B. Carstens, Birgit Weihrauch, Johannes A. Jehle
    Abstract:

    Abstract Both Agrotis Segetum nucleopolyhedrovirus B (AgseNPV-B) and Agrotis Segetum granulovirus (AgseGV) belong to a cluster of four baculoviruses that are infective for different Agrotis species. Belonging further to different baculovirus genera, namely Alphabaculovirus and Betabaculovirus, respectively, AgseNPV-B and AgseGV are candidates to investigate virus interactions in co-infections. However, for the investigation of virus interactions on a cellular level, permissive insect cell-lines are needed. The cell line AiE1611T deriving from Agrotis ipsilon eggs has been shown to be permissive for several Alphabaculovirus isolates. In this study, virus replication was followed based on microscopic analysis of infected and transfected cells, as well as on a molecular level by PCR of DNA and cDNA of selected baculovirus transcripts. While the permissivity was not verified for AgseGV, AgseNPV-B produced occlusion bodies in both infection with hemolymph of infected larvae and Lipofectamin transfection with AgseNPV-B genomic DNA. In addition to the possibility to investigate virus interaction of AgseNPV-B with other alphabaculoviruses, the permissivity of AiE1611T for AgseNPV-B further offers the possibility a biological selection to separate AgseNPV-B from AgseGV.

  • the genome sequence of Agrotis Segetum granulovirus isolate agsegv da reveals a new betabaculovirus species of a slow killing granulovirus
    Journal of Invertebrate Pathology, 2017
    Co-Authors: Gianpiero Gueli Alletti, Eric B. Carstens, Marina Eigenbrod, Regina G Kleespies, Johannes A. Jehle
    Abstract:

    Abstract The European isolate Agrotis Segetum granulovirus DA (AgseGV-DA) is a slow killing, type I granulovirus due to low dose-mortality responses within seven days post infection and a tissue tropism of infection restricted solely to the fat body of infected Agrotis Segetum host larvae. The genome of AgseGV-DA was completely sequenced and compared to the whole genome sequences of the Chinese isolates AgseGV-XJ and AgseGV-L1. All three isolates share highly conserved genomes. The AgseGV-DA genome is 131,557 bp in length and encodes for 149 putative open reading frames, including 37 baculovirus core genes and the per os infectivity factor ac110. Comprehensive investigations of repeat regions identified one putative non-hr like origin of replication in AgseGV-DA. Phylogenetic analysis based on concatenated amino acid alignments of 37 baculovirus core genes as well as pairwise distances based on the nucleotide alignments of partial granulin, lef-8 and lef-9 sequences with deposited betabaculoviruses confirmed AgseGV-DA, AgseGV-XJ and AgseGV-L1 as representative isolates of the same Betabaculovirus species. AgseGV encodes for a distinct putative enhancin, distantly related to enhancins from other granuloviruses.

  • Comparative study on the susceptibility of cutworms (Lepidoptera: Noctuidae) to Agrotis Segetum nucleopolyhedrovirus and Agrotis ipsilon nucleopolyhedrovirus
    Journal of invertebrate pathology, 2003
    Co-Authors: Said El-salamouny, Martin Lange, Manfred Jutzi, Jürg Huber, Johannes A. Jehle
    Abstract:

    The common cutworm (Agrotis Segetum) and the black cutworm (Agrotis ipsilon) are serious soil pests of many vegetable and field crops all over the world. We have demonstrated the cross-infectivity of two baculoviruses, A. Segetum nucleopolyhedrovirus (AgseNPV) and A. ipsilon nucleopolyhedrovirus (AgipNPV) for these two insect pests. The susceptibility of A. Segetum to AgipNPV was confirmed by DNA restriction endonuclease analyses of DNA isolated from virus harvested from infected A. Segetum larvae. For an initial comparison of both viruses, partial polyhedrin sequences were amplified by PCR, cloned, and sequenced. Both viruses shared a very similar polyhedrin gene sequence resulting in only three amino acid substitutions. Phylogenetic analyses clearly demonstrated that both viruses belong to NPV group II and are most closely related to a clade consisting of Spodoptera exigua NPV, Spodoptera frugiperda NPV, and Spodoptera littoralis NPV. Since AgipNPV shows high virulence for both cutworm species, it appears to be a suitable candidate as a single biological control agent of A. Segetum and A. ipsilon.

Just M. Vlak - One of the best experts on this subject based on the ideXlab platform.

  • a functional f analogue of autographa californica nucleopolyhedrovirus gp64 from the Agrotis Segetum granulovirus
    Journal of Virology, 2008
    Co-Authors: Feifei Yin, Ying Tan, Just M. Vlak
    Abstract:

    The envelope fusion protein F of Plutella xylostella granulovirus is a computational analogue of the GP64 envelope fusion protein of Autographa californica nucleopolyhedrovirus (AcMNPV). Granulovirus (GV) F proteins were thought to be unable to functionally replace GP64 in the AcMNPV pseudotyping system. In the present study the F protein of Agrotis Segetum GV (AgseGV) was identified experimentally as the first functional GP64 analogue from GVs. AgseF can rescue virion propagation and infectivity of gp64-null AcMNPV. The AgseF-pseudotyped AcMNPV also induced syncytium formation as a consequence of low-pH-induced membrane fusion.

  • genome sequence of an enhancin gene rich nucleopolyhedrovirus npv from Agrotis Segetum collinearity with spodoptera exigua multiple npv
    Journal of General Virology, 2006
    Co-Authors: Agata K. Jakubowska, Jadwiga Ziemnicka, Just M. Vlak, Sander Peters, Monique M. Van Oers
    Abstract:

    The genome sequence of a Polish isolate of Agrotis Segetum nucleopolyhedrovirus (AgseNPV-A) was determined and analysed. The circular genome is composed of 147544 bp and has a G+C content of 45?7 mol%. It contains 153 putative, non-overlapping open reading frames (ORFs) encoding predicted proteins of more than 50 aa, together making up 89?8% of the genome. The remaining 10?2% of the DNA constitutes non-coding regions and homologous-repeat regions. One hundred and forty-three AgseNPV-A ORFs are homologues of previously reported baculovirus gene sequences. There are ten unique ORFs and they account for 3% of the genome in total. All 62 lepidopteran baculovirus genes, including the 29 core baculovirus genes, were found in the AgseNPV-A genome. The gene content and gene order of AgseNPV-A are most similar to those of Spodoptera exigua (Se) multiple NPV and their shared homologous genes are 100% collinear. Three putative enhancin genes were identified in the AgseNPV-A genome. In phylogenetic analysis, the AgseNPV-A enhancins form a cluster separated from enhancins of the Mamestra species NPVs.

  • Molecular characterization of Agrotis Segetum nucleopolyhedrovirus from Poland.
    Journal of invertebrate pathology, 2005
    Co-Authors: Agata K. Jakubowska, Monique M. Van Oers, Jadwiga Ziemnicka, Jerzy J. Lipa, Just M. Vlak
    Abstract:

    The turnip moth, Agrotis Segetum (Lepidoptera, Noctuidae), is an important pest insect in Europe, Asia, and Africa. We have genetically characterized and classified a nucleopolyhedrovirus isolated from A. Segetum larvae in Poland (AgseNPV-P). The restriction pattern of AgseNPV-P was distinct from an isolate from England/France (AgseNPV-UK and AgseNPV-F). Sequence analysis of three conserved baculovirus genes, polyhedrin, lef-8 and pif-2, revealed that AgseNPV-P differs substantially from the already described NPVs isolated from A. Segetum and possibly represents a new NPV species. Phylogenetic analysis placed AgseNPV-P among group II NPVs and showed the closest relationship to Agrotis ipsilon (Agip) NPV and Spodoptera exigua (Se) MNPV.

Hansson B. - One of the best experts on this subject based on the ideXlab platform.

  • Responses in highly selective sensory neurons to blends of pheromone components in the moth Agrotis Segetum
    2002
    Co-Authors: Carlsson M., Hansson B.
    Abstract:

    Pheromone detecting sensory neurons in moths are known to be highly sensitive and selective. Female-emitted sexual pheromones are normally mixtures of a few to several components. However, not much is known about how receptor neurons respond to blends of compounds. In the present study we investigated how four physiological types of pheromone component-selective neurons responded to binary mixtures or to the complete blend in the turnip moth Agrotis Segetum. We found that responses to mixtures only rarely differed from that to the excitatory component alone. The mixture interactions were exclusively suppressive and occurred only at high concentrations. Therefore we conclude that the, in A. Segetum, commonly observed mixture interactions observed in higher brain centra are mainly the result of central nervous processing and that information about the pheromone components reaches the antennal lobes virtually unaltered. In addition, we found a physiological type of receptor neuron, responding selectively to one of the female-emitted pheromone components, that has previously not been observed in the Swedish population. (C) 2002 Elsevier Science Ltd. All rights reserved

  • Olfactory protocerebral pathways processing sex pheromone and plant odor information in the male moth Agrotis Segetum
    'Wiley', 2001
    Co-Authors: Lei H, Anton S., Hansson B.
    Abstract:

    We investigated protocerebral processing of behaviorally relevant signals in the turnip moth, Agrotis Segetum. Single neurons were studied both physiologically and morphologically using intracellular recording techniques. In moth pheromone communication systems, the presence of the complete, female-produced pheromone blend is necessary for male attraction. We predicted that more protocerebral neurons, compared with AL, would display blend interactions. However, only a few protocerebral neurons responded differently to the blend than could be deduced from the response to single components. The majority of the pheromone-sensitive protocerebral neurons identified in this study responded to the major pheromone component. In coding time, most AL neurons can follow a 5-Hz odor stimulus, whereas most protocerebral neurons failed at higher frequencies than 1 Hz. The majority of neurons that responded to the odorants tested innervated one or both of the protocerebral lateral accessory lobes. If only one of these was innervated, then the innervation always displayed a varicose appearance, suggesting a presynaptic function. Thus, information seems to be transferred from other protocerebral. areas to the lateral accessory lobes. Into these, descending neurons sent smooth, postsynaptic branches. A majority of the neurons innervating the superior medial protocerebrum were found to display single-component specificity. Few additional correlations between odor specificity and structural characteristics were apparent. (C) 2001 Wiley-Liss, Inc

  • Central processing of pulsed pheromone signals by antennal lobe neurons in the male moth Agrotis Segetum
    'American Physiological Society', 1999
    Co-Authors: Lei H, Hansson B.
    Abstract:

    Male moths use female-produced pheromones as orientation cues during the mate-finding process. In addition to the needs of evaluating the quality and quantity of the pheromone signal, the male moth also needs to resolve the filamentous structure of the pheromone plume to proceed toward the releasing point successfully. To understand how a discontinuous olfactory signal is processed at the central lever, we used intracellular recording methods to characterize the response patterns of antennal lobe (AL) neurons to pulsatile stimulation with the full female-produced pheromone blend and its single components in male turnip moths, Agrotis Segetum. Air puffs delivered at frequencies of 1, 3, 5, 7, or 10 Hz were used to carry the stimulus. Two types of AL neurons were characterized according to their capabilities to resolve stimulus pulses. The most common type could resolve at least l-Hz pulses, thus termed fast neurons; another type could not resolve any pulses, thus termed slow neurons. When fast neurons were excited by stimuli, they always displayed biphasic response patterns, a depolarization phase followed by a hyperpolarization phase. This pattern could be evoked by stimulation with both the single pheromone components and the blend. The pulse-resolving capability of the fast neurons correlated significantly with the size of the hyperpolarization phase. When the amplitude was higher and the fall time of the hyperpolarization faster, the neuron could follow more pulses per second. Moreover, interactions between different pheromone components eliciting different response patterns did not improve the pulse-resolving capability of fast neurons

  • Comparative study of pheromone production and response in Swedish and Zimbabwean populations of turnip moth, Agrotis Segetum
    'Springer Science and Business Media LLC', 1999
    Co-Authors: Wu W., Hansson B., Cottrell C., Löfstedt C.
    Abstract:

    Analysis of female sex pheromone gland extracts of the turnip moth (or common cutworm), Agrotis Segetum, from Zimbabwe revealed three compounds previously identified as sex pheromone components in the Swedish population, namely (Z)-5-decenyl acetate (Z5-10:OAc), (Z)-7-dodecenyl acetate (Z7-12:OAc), and (Z)-9-tetradecenyl acetate (Z9-14:OAc). However, the proportions from the Zimbabwean population (1 :0.25:0.03) differ from those in the Swedish population(1 :5 :2.5). In addition, gas chromatography-mass spectrometric (GC-MS) analysis of the Zimbabwean female gland extracts revealed a trace of (Z)-5-dodecenyl acetate (Z5-12:OAc). This compound has recently been identified as a fourth sex pheromone component for the Swedish population. Single-sensillum recordings from both Zimbabwean and Swedish populations showed the presence of two types of antennal receptors responding to either Z5-10:OAc or Z7-12:OAc. In Zimbabwean males the Z7-12:OAc receptor neuron appeared to be confined to the basal and medial thirds of the antennal branches, while in Swedish males it was distributed along the entire antennal branch. Dose-response curves of Z5-10:OAc or Z7-12:OAc specific receptor neurons from males of both populations showed similar response profiles, but the neurons of the Zimbabwean population showed higher maximal responses. In Eight tunnel tests with Zimbabwean males, the three-component Zimbabwean blend of Z5-10:OAc, Z7-12:OAc and Z9-14:OAc elicited significantly greater responses than the Swedish blend, but not significantly greater than pheromone glands from calling Zimbabwean females. (Z)-5-decenol (Z5-10:OH), a constituent of gland extracts, exerted an antagonistic effect in the flight tunnel. In field tests conducted in Sweden, local males were preferentially attracted to local females, while in Zimbabwe preferential attraction to local females was less pronounced. Local response to the Swedish and Zimbabwean synthetic four-component blends mirrored the responses to the local females. Zimbabwean males are much more strongly attracted to Z5-10:OAc alone than are Swedish males and the high concentrations of Z7-12:OAc and/or Z9-14:OAc present in the Swedish blend reduced attraction of Zimbabwean males. This reduced attraction appears to be counteracted by the trace amounts of Z5-12:OAc found in the Swedish four-component blend. Addition of Z5-12:OAc to the three-component Zimbabwean blend did not. however. significantly increase the trap catches of Zimbabwean males

  • Conformationally constrained analogues of (Z)-5-decenyl acetate, a pheromone component of Agrotis Segetum
    'Elsevier BV', 1996
    Co-Authors: Jönsson S., Hansson B., Liljefors T.
    Abstract:

    Conformationally constrained analogues of (Z)-5-decenyl acetate (1), a pheromone component of the turnip moth, Agrotis Segetum, have been synthesized and tested by using electrophysiological single-cell recordings. In the constrained analogues the terminal alkyl chain in 1 has been incorporated in a six-membered (3 and 1) or five-membered (6) ring system. These cyclic compounds are also conformationally constrained analogues of the previously deduced bioactive conformations of the corresponding chain-elongated analogues 2 and 5. The electrophysiological activities of the constrained analogues are found to be significantly lower than that of the natural pheromone component 1, most probably due to steric repulsive interactions between the analogue and the receptor, and also lower than the activities of the corresponding chain-elongated analogues of 1. It is concluded that the flexibility of the terminal chains in 2 and 5 is essential for the possibility of the receptor to accommodate these parts of the chain-elongated analogues in their bioactive conformations. Copyright (C) 1996 Elsevier Science Lt