The Experts below are selected from a list of 186 Experts worldwide ranked by ideXlab platform
David L Denlinger - One of the best experts on this subject based on the ideXlab platform.
-
diapause hormone in the corn earworm helicoverpa zea optimum temperature for activity structure activity relationships and efficacy in accelerating flesh fly Pupariation
Peptides, 2008Co-Authors: Qirui Zhang, Jan Zdarek, Ronald J. Nachman, David L DenlingerAbstract:Abstract Diapause hormone (DH) effectively terminated pupal diapause in Helicoverpa zea. This effect was temperature-dependent, with an optimum of 21 °C. The dose–response curve indicated an ED50 of DH for diapause termination of approximately 100 pmol. The core sequence and essential amino acids were determined by bioassays using modified and truncated DH analogs. A C-terminal hepta-peptide, LWFGPRLa, was the core sequence required for diapause termination. Activity was lost when Alanine was substituted for any of the amino acids in the hepta-peptide, with the exception of Glycine. A fragment series of analogs suggested that the amide and Arginine were the most important components needed for terminating diapause. Leucine, Tryptophan, and Phenylalanine at the N-terminus of the hepta-peptide were also critical for activity. The C-terminal Leucine was less important: deletion resulted in decreased activity, although it could not be substituted by Alanine. The fact that a portion of the DH sequence is similar to the pyrokinin that accelerates fly Pupariation prompted us to also evaluate the capability of DH to accelerate development in the flesh fly, Sarcophaga bullata. The threshold dose of DH essential to accelerate fly Pupariation was 5 pmol for immobilization/retraction and longitudinal contraction and 10 pmol for tanning, approximately one or two orders of magnitude lower than the effective dose required for diapause termination in H. zea. Tensiometric measurements revealed that DH affected neuromuscular patterns of Pupariation behavior and associated cuticular changes in a manner similar to that of the fly pyrokinins and their analogs.
-
temporal expression patterns of diapause associated genes in flesh fly pupae from the onset of diapause through post diapause quiescence
Journal of Insect Physiology, 2005Co-Authors: Scott A L Hayward, Savvas Pavlides, Steven P Tammariello, Joseph P Rinehart, David L DenlingerAbstract:Abstract Distinct differences in the temporal expression patterns of genes associated with pupal diapause were noted in the flesh fly, Sarcophaga crassipalpis. The first change observed was a decline in expression of the gene encoding heat shock protein 90 (hsp90) 2 days after Pupariation (1 day before the pupa reaches the phanerocephalic stage characteristic of diapause). In contrast, hsp23 and hsp70 transcripts were undetectable in nondiapause samples and d1–d4 diapause-programmed pupae, but were up-regulated just after the start of diapause, 5 days after Pupariation. An increase of glycerol content in diapausing pupae was also noted at the start of diapause. The gene encoding proliferating cell nuclear antigen (pcna) was diapause down-regulated, and this occurred in two phases, with the first decline in expression 7 days after Pupariation and a second decline in the level of expression on day 14. For pupae held at 20 °C for 20 days and transferred to 10 °C, diapause ended after 90–100 days at the lower temperature. However, pupae remained in a state of post-diapause quiescence (d100–d150) and sustained diapause-like hsp and pcna expression patterns until adult development was initiated. Glycerol concentrations and survival declined during the post-diapause phase. This study suggests a distinct sequence in the pattern of gene expression at the onset of diapause, but the genes we have monitored do not contribute to the switch to covert developmental potential at the transition from diapause to post-diapause quiescence.
-
disruption of Pupariation and eclosion behavior in the flesh fly sarcophaga bullata parker diptera sarcophagidae by venom from the ectoparasitic wasp nasonia vitripennis walker hymenoptera pteromalidae
Archives of Insect Biochemistry and Physiology, 2004Co-Authors: David B Rivers, Jan Zdarek, David L DenlingerAbstract:The action of venom from the ectoparasitic wasp, Nasonia vitripennis, was monitored by examining alterations in patterned muscular movements characteristic of Pupariation and eclosion behavior in the flesh fly, Sarcophaga bullata. Venom injected into larvae prior to Pupariation caused a dose-dependent delay in Pupariation. Eventually, such larvae did pupariate, but puparia were abnormally formed. Barographic records revealed that all elements of Pupariation behavior were present in venom-injected larvae, but Pupariation behavior was not well synchronized with tanning, thus implying that the venom caused disruption in the temporal organization of central motor programs. When larvae were ligated and injected with venom posterior to the ligature, no response was evident in the posterior region, suggesting that the venom does not directly stimulate muscles or neuromuscular junctions. Injection of exogenous ecdysteroid into venom-injected larvae restored some elements of Pupariation behavior, consistent with ecdysone’s role in stimulating the release of anterior retraction factor and puparium tanning factor, two factors that are released from the CNS to regulate Pupariation. When the venom was injected into newly emerged imagoes, the duration of extrication behavior was shortened, whereas all phases of post-eclosion behavior were lengthened. These observations imply that the venom affects CNS centers that regulate the muscular systems engaged in extrication and post-eclosion behavior. Arch. Insect Biochem. Physiol. 57:78–91, 2004. © 2004 Wiley-Liss, Inc.
-
developmental fate of the flesh fly sarcophaga bullata envenomated by the pupal ectoparasitoid nasonia vitripennis
Journal of Insect Physiology, 1994Co-Authors: David B Rivers, David L DenlingerAbstract:Pupae and pharate adults of Sarcophaga bullata parasitized by the ectoparasitoid, Nasonia vitripennis, either died immediately or entered a developmental arrest. Death was the dominant response in young pupae (2 days after Pupariation) and late pharate adults (>9 days after Pupariation): death occurred within 48 h after envenomation, even in the absence of parasitoid larvae. The dominant response of intermediate aged hosts (3–9 days after Pupariation) was an arrested or retarded development, the duration of which was age-dependent. Hosts envenomated as pupae remained arrested as pupae. Development progressed slowly in hosts envenomated as pharate adults, but none succeeded in completing pharate adult development. Likewise, diapausing hosts were developmentally suppressed following envenomation and appeared to be “preserved” for up to 40 days before death occurred. Host arrestment was induced by injection of wasp venom and was independent of the presence of parasitoid larvae. Envenomation in the anterior half of the body was more deleterious to the host than envenomation in the posterior half: with anterior injection, death was more rapid and far fewer hosts succeeded in depositing eye pigment or forming body bristles. Host arrestment could not be countered with injection of 20-hydroxyecdysone, thus suggesting the developmental suppression is not the consequence of an ecdysteroid deficiency. Progeny production by N. vitripennis was nearly the same on an intact host as on an isolated thorax-abdomen of the host, but far fewer progeny were produced on an isolated head-thorax preparation of the host. This suggests that either a factor in the head region is detrimental to parasitoid development or some aspect of the abdomen promotes parasitoid development.
-
Neural regulation of Pupariation in tsetse larvae.
The Journal of experimental biology, 1992Co-Authors: Jan Zdarek, David L DenlingerAbstract:A neural mechanism coordinates Pupariation behavior and tanning in the tsetse larva. At parturition, the mature larva has already received sufficient ecdysteroid to commit the epidermal cells to metamorphosis but, before sclerotization and tanning of the cuticle can begin, the larva must first select a Pupariation site and then proceed through a stereotypic sequence of Pupariation behavior that culminates in the formation of a smooth, ovoid puparium. Both Pupariation behavior and tanning are inhibited by the central nervous system (CNS) during the wandering phase. This central inhibition is maintained by sensory input originating in the extreme posterior region of the body. At the transition from wandering to Pupariation, the posterior signal that induces inhibition of Pupariation behavior is removed and the larva begins the contractions associated with Pupariation, but the CNS inhibition of tanning persists. At this point, separation of the body into two halves by ligation or nerve transection prevents tanning of the anterior half (containing the CNS), whereas the denervated integument of the posterior half tans completely. Transection of nerves to the midline of the body produces larvae with a tanning pattern that ends abruptly along a sagittal plane, implying that the central control of this process is uncoupled between the left and right regions of the CNS. A few minutes later, when the final shape of the puparium is completed, the CNS inhibition is lifted and the tanning process begins. At this time, separation of the body into two halves by ligation or nerve transection has no inhibitory effects on either part. Exogenous ecdysteroids fail to release the CNS inhibition, and hemolymph containing the Pupariation factors from Sarcophaga bullata have no accelerating effects on tsetse Pupariation. These results imply that regulation of metamorphosis in the insect integument is not the exclusive domain of blood-borne hormones.
Jan Zdarek - One of the best experts on this subject based on the ideXlab platform.
-
diapause hormone in the corn earworm helicoverpa zea optimum temperature for activity structure activity relationships and efficacy in accelerating flesh fly Pupariation
Peptides, 2008Co-Authors: Qirui Zhang, Jan Zdarek, Ronald J. Nachman, David L DenlingerAbstract:Abstract Diapause hormone (DH) effectively terminated pupal diapause in Helicoverpa zea. This effect was temperature-dependent, with an optimum of 21 °C. The dose–response curve indicated an ED50 of DH for diapause termination of approximately 100 pmol. The core sequence and essential amino acids were determined by bioassays using modified and truncated DH analogs. A C-terminal hepta-peptide, LWFGPRLa, was the core sequence required for diapause termination. Activity was lost when Alanine was substituted for any of the amino acids in the hepta-peptide, with the exception of Glycine. A fragment series of analogs suggested that the amide and Arginine were the most important components needed for terminating diapause. Leucine, Tryptophan, and Phenylalanine at the N-terminus of the hepta-peptide were also critical for activity. The C-terminal Leucine was less important: deletion resulted in decreased activity, although it could not be substituted by Alanine. The fact that a portion of the DH sequence is similar to the pyrokinin that accelerates fly Pupariation prompted us to also evaluate the capability of DH to accelerate development in the flesh fly, Sarcophaga bullata. The threshold dose of DH essential to accelerate fly Pupariation was 5 pmol for immobilization/retraction and longitudinal contraction and 10 pmol for tanning, approximately one or two orders of magnitude lower than the effective dose required for diapause termination in H. zea. Tensiometric measurements revealed that DH affected neuromuscular patterns of Pupariation behavior and associated cuticular changes in a manner similar to that of the fly pyrokinins and their analogs.
-
A Beta-Amino Acid Pyrokinin Analog Induces Irregular Pupariation Behavior in Larvae of the Flesh Fly Sarcophaga bullata
2008Co-Authors: Ronald J. Nachman, Pawel Zubrzak, Howard J. Williams, Allison Strey, Jan ZdarekAbstract:Abstract : The developmental process of Pupariation is accelerated by members of the pyrokinin class of neuropeptides in larvae of the flesh fly Sarcophaga bullata. A pyrokinin analog (Ac-Y[beta3Phe]TPRLamide), in which a Phe residue is replaced with a beta-amino acid, accelerates Pupariation in this fly at a potency (0.2 pmol/larva) that matches that of the native pyrokinin factor. At higher concentrations, this beta-amino acid pyrokinin analog induces irregular Pupariation behavior patterns that are suggestive of neurotoxic properties. Biostable analogs based on this structure may in future provide analog leads with the potential to disrupt the important Pupariation process in flies.)
-
A comparison of the Pupariation acceleration activity of pyrokinin-like peptides native to the flesh fly: Which peptide represents the primary Pupariation factor?
Peptides, 2005Co-Authors: Ronald J. Nachman, Pawel Zubrzak, Allison Strey, Jan ZdarekAbstract:Five native pyrokinin-like peptides (Neb-PK-1, Neb-PK-2, Neb-PVK-1, [L9]Neb-PVK-2, [I9]Neb-PVK-2) identified in the neuropeptidome of the flesh fly Neobellieria bullata were compared for their quantitative and/or qualitative effects on puparium formation (Pupariation). In a standard Pupariation bioassay, both Neb-PVK-1 and [I9]Neb-PVK-2 proved inactive, whereas [L9]Neb-PVK-2 demonstrated only weak activity. In contrast, both Neb-PK-1 and Neb-PK-2 demonstrated potent threshold doses, with Neb-PK-2 about 10-fold more active than Neb-PK-1. Analysis of neuromuscular activity during Pupariation using a tensiometric technique demonstrates that the two native Neb-PKs accelerate the onset of immobilization and cuticular shrinkage more than motor programs associated with retraction of the anterior segments and longitudinal body contraction. It was further determined that the sensitivity of various components of the Pupariation process to these peptides decreases in the following order: immobilization>cuticular shrinkage>motor program for anterior retraction>motor program for longitudinal contraction congruent to tanning of cuticle of the newly formed puparium. A paradoxical situation was observed whereby the motor programs of Pupariation are temporally dissociated from actual morphogenesis of the puparium. The tensiometric data suggest that the most likely candidate for a primary Pupariation factor is Neb-PK-2, rather than Neb-PK-1.
-
disruption of Pupariation and eclosion behavior in the flesh fly sarcophaga bullata parker diptera sarcophagidae by venom from the ectoparasitic wasp nasonia vitripennis walker hymenoptera pteromalidae
Archives of Insect Biochemistry and Physiology, 2004Co-Authors: David B Rivers, Jan Zdarek, David L DenlingerAbstract:The action of venom from the ectoparasitic wasp, Nasonia vitripennis, was monitored by examining alterations in patterned muscular movements characteristic of Pupariation and eclosion behavior in the flesh fly, Sarcophaga bullata. Venom injected into larvae prior to Pupariation caused a dose-dependent delay in Pupariation. Eventually, such larvae did pupariate, but puparia were abnormally formed. Barographic records revealed that all elements of Pupariation behavior were present in venom-injected larvae, but Pupariation behavior was not well synchronized with tanning, thus implying that the venom caused disruption in the temporal organization of central motor programs. When larvae were ligated and injected with venom posterior to the ligature, no response was evident in the posterior region, suggesting that the venom does not directly stimulate muscles or neuromuscular junctions. Injection of exogenous ecdysteroid into venom-injected larvae restored some elements of Pupariation behavior, consistent with ecdysone’s role in stimulating the release of anterior retraction factor and puparium tanning factor, two factors that are released from the CNS to regulate Pupariation. When the venom was injected into newly emerged imagoes, the duration of extrication behavior was shortened, whereas all phases of post-eclosion behavior were lengthened. These observations imply that the venom affects CNS centers that regulate the muscular systems engaged in extrication and post-eclosion behavior. Arch. Insect Biochem. Physiol. 57:78–91, 2004. © 2004 Wiley-Liss, Inc.
-
Fraenkel's Pupariation factor identified at last.
Developmental biology, 2004Co-Authors: Peter Verleyen, Jan Zdarek, Elke Clynen, Jurgen Huybrechts, Alfons Van Lommel, Luc Vanden Bosch, Arnold De Loof, Liliane SchoofsAbstract:Thirty-five years ago, Zdarek and Fraenkel demonstrated that nervous tissue extracts influenced development by accelerating Pupariation in the grey flesh fly, Neobellieria bullata. We have now identified this Pupariation factor as SVQFKPRLamide, designated Neb-pyrokinin-2 (Neb-PK-2). To achieve this, the central nervous system of N. bullata wandering stage larvae, that is, preceding Pupariation, were dissected and extracted before HPLC separation. Chromatographic fractions were screened with a bioassay for Pupariation accelerating activity. Only one fraction showed huge Pupariation activity. Mass spectrometry revealed the presence of a pyrokinin, whose primary sequence could not be unequivocally determined by tandem mass spectrometry. However, this Neb-pyrokinin appeared to be very prominent in the ring gland from which it was subsequently purified and identified. Synthetic Neb-PK-2 accelerates Pupariation with a threshold dose of only 0.2 pmol and therefore, Neb-pyrokinin is considered to be the genuine Pupariation factor. The immunohistochemical distribution pattern of Neb-PK-2 is very similar to that of Drosophila pyrokinin-2, from which it differs by only one amino acid residue. Hence, the recently identified G-protein coupled receptors (CG8784, CG8795) for Drosophila pyrokinin-2 might play an important role in puparium formation.
Ronald J. Nachman - One of the best experts on this subject based on the ideXlab platform.
-
Biostable β-amino acid PK/PBAN analogs: Agonist and antagonist properties
Peptides, 2008Co-Authors: Ronald J. Nachman, Pawel Zubrzak, Howard J. Williams, Allison Strey, Orna Ben Aziz, Michael Davidovitch, R. Elwyn Isaac, Gloria Reyes-rangel, Eusebio Juaristi, Miriam AltsteinAbstract:The pyrokinin/pheromone biosynthesis activating neuropeptide (PK/PBAN) family plays a significant role in a multifunctional array of important physiological processes in insects. PK/PBAN analogs incorporating b-amino acids were synthesized and evaluated in a pheromonotropic assay in Heliothis peltigera, a melanotropic assay in Spodoptera littoralis, a Pupariation assay in Neobellieria bullata, and a hindgut contractile assay in Leucophaea maderae. Two analogs (PK-bA-1 and PK-bA-4) demonstrate greatly enhanced resistance to the peptidases neprilysin and angiotensin converting enzyme that are shown to degrade the natural peptides. Despite the changes to the PK core, analog PK-bA-4 represents a biostable, non-selective agonist in all four bioassays, essentially matching the potency of a natural PK in Pupariation assay. Analog PK-bA-2 is a potent agonist in the melanotropic assay, demonstrating full efficacy at 1 pmol. In some cases, the structural changes imparted to the analogs modify the physiological responses. Analog PK-bA-3 is a non-selective agonist in all four bioassays. The analog PK- bA-1 shows greater selectivity than parent PK peptides; it is virtually inactive in the Pupariation assay and represents a biostable antagonist in the pheromonotropic and melanotropic assays, without the significant agonism of the parent hexapeptide. These analogs provide new, and in some cases, biostable tools to endocrinologists studying similarities and differences in the mechanisms of the variety of PK/ PBAN mediated physiological processes. They also may provide leads in the development of PK/PBAN- based, insect-specific pest management agents.
-
diapause hormone in the corn earworm helicoverpa zea optimum temperature for activity structure activity relationships and efficacy in accelerating flesh fly Pupariation
Peptides, 2008Co-Authors: Qirui Zhang, Jan Zdarek, Ronald J. Nachman, David L DenlingerAbstract:Abstract Diapause hormone (DH) effectively terminated pupal diapause in Helicoverpa zea. This effect was temperature-dependent, with an optimum of 21 °C. The dose–response curve indicated an ED50 of DH for diapause termination of approximately 100 pmol. The core sequence and essential amino acids were determined by bioassays using modified and truncated DH analogs. A C-terminal hepta-peptide, LWFGPRLa, was the core sequence required for diapause termination. Activity was lost when Alanine was substituted for any of the amino acids in the hepta-peptide, with the exception of Glycine. A fragment series of analogs suggested that the amide and Arginine were the most important components needed for terminating diapause. Leucine, Tryptophan, and Phenylalanine at the N-terminus of the hepta-peptide were also critical for activity. The C-terminal Leucine was less important: deletion resulted in decreased activity, although it could not be substituted by Alanine. The fact that a portion of the DH sequence is similar to the pyrokinin that accelerates fly Pupariation prompted us to also evaluate the capability of DH to accelerate development in the flesh fly, Sarcophaga bullata. The threshold dose of DH essential to accelerate fly Pupariation was 5 pmol for immobilization/retraction and longitudinal contraction and 10 pmol for tanning, approximately one or two orders of magnitude lower than the effective dose required for diapause termination in H. zea. Tensiometric measurements revealed that DH affected neuromuscular patterns of Pupariation behavior and associated cuticular changes in a manner similar to that of the fly pyrokinins and their analogs.
-
A Beta-Amino Acid Pyrokinin Analog Induces Irregular Pupariation Behavior in Larvae of the Flesh Fly Sarcophaga bullata
2008Co-Authors: Ronald J. Nachman, Pawel Zubrzak, Howard J. Williams, Allison Strey, Jan ZdarekAbstract:Abstract : The developmental process of Pupariation is accelerated by members of the pyrokinin class of neuropeptides in larvae of the flesh fly Sarcophaga bullata. A pyrokinin analog (Ac-Y[beta3Phe]TPRLamide), in which a Phe residue is replaced with a beta-amino acid, accelerates Pupariation in this fly at a potency (0.2 pmol/larva) that matches that of the native pyrokinin factor. At higher concentrations, this beta-amino acid pyrokinin analog induces irregular Pupariation behavior patterns that are suggestive of neurotoxic properties. Biostable analogs based on this structure may in future provide analog leads with the potential to disrupt the important Pupariation process in flies.)
-
A comparison of the Pupariation acceleration activity of pyrokinin-like peptides native to the flesh fly: Which peptide represents the primary Pupariation factor?
Peptides, 2005Co-Authors: Ronald J. Nachman, Pawel Zubrzak, Allison Strey, Jan ZdarekAbstract:Five native pyrokinin-like peptides (Neb-PK-1, Neb-PK-2, Neb-PVK-1, [L9]Neb-PVK-2, [I9]Neb-PVK-2) identified in the neuropeptidome of the flesh fly Neobellieria bullata were compared for their quantitative and/or qualitative effects on puparium formation (Pupariation). In a standard Pupariation bioassay, both Neb-PVK-1 and [I9]Neb-PVK-2 proved inactive, whereas [L9]Neb-PVK-2 demonstrated only weak activity. In contrast, both Neb-PK-1 and Neb-PK-2 demonstrated potent threshold doses, with Neb-PK-2 about 10-fold more active than Neb-PK-1. Analysis of neuromuscular activity during Pupariation using a tensiometric technique demonstrates that the two native Neb-PKs accelerate the onset of immobilization and cuticular shrinkage more than motor programs associated with retraction of the anterior segments and longitudinal body contraction. It was further determined that the sensitivity of various components of the Pupariation process to these peptides decreases in the following order: immobilization>cuticular shrinkage>motor program for anterior retraction>motor program for longitudinal contraction congruent to tanning of cuticle of the newly formed puparium. A paradoxical situation was observed whereby the motor programs of Pupariation are temporally dissociated from actual morphogenesis of the puparium. The tensiometric data suggest that the most likely candidate for a primary Pupariation factor is Neb-PK-2, rather than Neb-PK-1.
-
comparison of the effects of pyrokinins and related peptides identified from arthropods on Pupariation behaviour in flesh fly sarcophaga bullata larvae diptera sarcophagidae
Journal of Insect Physiology, 2004Co-Authors: Jan Zdarek, Peter Verleyen, Michael Mares, Lucie Doleckova, Ronald J. NachmanAbstract:Peptides from the pyrokinin/PBAN family and some structurally related compounds identified in various arthropods were tested for acceleration of puparial contraction in flesh fly larvae. Modifications of behavioural patterns of Pupariation were further studied for the active compounds using a behavioural analysis based on the recording of changes in tension of the cuticle. Nine peptides belonging to the pyrokinin/PBAN family (Lem-PK, Pea-PK-5, Lom-PK II, Hez-PBAN, Bom-DH-I), identified in five different insect species, two pyrokinin peptides derived from the genome of Drosophila melanogaster (capa-3, and hugin), and two pyrokinins identified from the white shrimp Penaeus vannamei were very active in the Pupariation assay, with threshold doses within the range of 0.1–5.0 pmol larva−1. High activity was also detected for a related peptide ETH1 from Drosophila. All of these peptides share a C-terminal PRLamide, which is essential and sufficient for the activity. Interestingly, two other structurally related peptides from Drosophila—ETH2 and capa-1—which feature conservative changes (Ile and Val, respectively) at the C-terminal Leu position, were inactive within a physiological range of concentrations. It is clear that the receptor mediating the acceleration of puparial contraction behaviour is sensitive to the introduction of greater steric bulk at the C-terminal Leu position. The peptides that accelerated Pupariation showed very similar patterns of muscular and cuticular activity.
David B Rivers - One of the best experts on this subject based on the ideXlab platform.
-
disruption of Pupariation and eclosion behavior in the flesh fly sarcophaga bullata parker diptera sarcophagidae by venom from the ectoparasitic wasp nasonia vitripennis walker hymenoptera pteromalidae
Archives of Insect Biochemistry and Physiology, 2004Co-Authors: David B Rivers, Jan Zdarek, David L DenlingerAbstract:The action of venom from the ectoparasitic wasp, Nasonia vitripennis, was monitored by examining alterations in patterned muscular movements characteristic of Pupariation and eclosion behavior in the flesh fly, Sarcophaga bullata. Venom injected into larvae prior to Pupariation caused a dose-dependent delay in Pupariation. Eventually, such larvae did pupariate, but puparia were abnormally formed. Barographic records revealed that all elements of Pupariation behavior were present in venom-injected larvae, but Pupariation behavior was not well synchronized with tanning, thus implying that the venom caused disruption in the temporal organization of central motor programs. When larvae were ligated and injected with venom posterior to the ligature, no response was evident in the posterior region, suggesting that the venom does not directly stimulate muscles or neuromuscular junctions. Injection of exogenous ecdysteroid into venom-injected larvae restored some elements of Pupariation behavior, consistent with ecdysone’s role in stimulating the release of anterior retraction factor and puparium tanning factor, two factors that are released from the CNS to regulate Pupariation. When the venom was injected into newly emerged imagoes, the duration of extrication behavior was shortened, whereas all phases of post-eclosion behavior were lengthened. These observations imply that the venom affects CNS centers that regulate the muscular systems engaged in extrication and post-eclosion behavior. Arch. Insect Biochem. Physiol. 57:78–91, 2004. © 2004 Wiley-Liss, Inc.
-
developmental fate of the flesh fly sarcophaga bullata envenomated by the pupal ectoparasitoid nasonia vitripennis
Journal of Insect Physiology, 1994Co-Authors: David B Rivers, David L DenlingerAbstract:Pupae and pharate adults of Sarcophaga bullata parasitized by the ectoparasitoid, Nasonia vitripennis, either died immediately or entered a developmental arrest. Death was the dominant response in young pupae (2 days after Pupariation) and late pharate adults (>9 days after Pupariation): death occurred within 48 h after envenomation, even in the absence of parasitoid larvae. The dominant response of intermediate aged hosts (3–9 days after Pupariation) was an arrested or retarded development, the duration of which was age-dependent. Hosts envenomated as pupae remained arrested as pupae. Development progressed slowly in hosts envenomated as pharate adults, but none succeeded in completing pharate adult development. Likewise, diapausing hosts were developmentally suppressed following envenomation and appeared to be “preserved” for up to 40 days before death occurred. Host arrestment was induced by injection of wasp venom and was independent of the presence of parasitoid larvae. Envenomation in the anterior half of the body was more deleterious to the host than envenomation in the posterior half: with anterior injection, death was more rapid and far fewer hosts succeeded in depositing eye pigment or forming body bristles. Host arrestment could not be countered with injection of 20-hydroxyecdysone, thus suggesting the developmental suppression is not the consequence of an ecdysteroid deficiency. Progeny production by N. vitripennis was nearly the same on an intact host as on an isolated thorax-abdomen of the host, but far fewer progeny were produced on an isolated head-thorax preparation of the host. This suggests that either a factor in the head region is detrimental to parasitoid development or some aspect of the abdomen promotes parasitoid development.
Guy Smagghe - One of the best experts on this subject based on the ideXlab platform.
-
Additional file 4: of RNA-seq analysis of gene expression changes during Pupariation in Bactrocera dorsalis (Hendel) (Diptera: Tephritidae)
2018Co-Authors: Er-hu Chen, Qiu-li Hou, Wei Dou, Dan-dan Wei, Yong Yue, Rui-lin Yang, Kristof De Schutter, Guy Smagghe, Jin-jun WangAbstract:Table S3. All genes FPKM value during the Pupariation in Bactrocera dorsalis. (XLSX 1346 kb
-
Additional file 12: of RNA-seq analysis of gene expression changes during Pupariation in Bactrocera dorsalis (Hendel) (Diptera: Tephritidae)
2018Co-Authors: Er-hu Chen, Qiu-li Hou, Wei Dou, Dan-dan Wei, Yong Yue, Rui-lin Yang, Kristof De Schutter, Guy Smagghe, Jin-jun WangAbstract:Table S6. The detail FPKM value of 20-hydroxyecdysone biosynthesis and signaling related genes during the Pupariation in Bactrocera dorsalis. (XLSX 12 kb
-
a role of corazonin receptor in larval pupal transition and Pupariation in the oriental fruit fly bactrocera dorsalis hendel diptera tephritidae
Frontiers in Physiology, 2017Co-Authors: Hongbo Jiang, Er-hu Chen, Guy Smagghe, Jin-jun Wang, Huimin LiAbstract:Corazonin (Crz) is a neuropeptide hormone, but also a neuropeptide modulator that is internally released within the CNS, and it has a widespread distribution in insects with diverse physiological functions. Here, we identified and cloned the cDNAs of Bactrocera dorsalis that encode Crz and its receptor CrzR. Mature BdCrz has 11 residues with a unique Ser11 substitution (instead of the typical Asn) and a His in the evolutionary variable position 7. The BdCrzR cDNA encodes a putative protein of 608 amino acids with 7 putative transmembrane domains, typical for the structure of G-protein-coupled receptors. When expressed in Chinese hamster ovary (CHO) cells, the BdCrzR exhibited a high sensitivity and selectivity for Crz (EC50 ≈ 52.5 nM). With qPCR, the developmental stage and tissue-specific expression profiles in B. dorsalis demonstrated that both BdCrz and BdCrzR were highly expressed in the larval stage, and BdCrzR peaked in 2-day-old 3rd-instar larvae, suggesting that the BdCrzR may play an important role in the larval-pupal transition behavior. Immunochemical localization confirmed the production of Crz in the central nervous system (CNS), specifically by a group of three neurons in the dorso-lateral protocerebrum and eight pairs of lateral neurons in the ventral nerve cord. qPCR analysis located the BdCrzR in both the CNS and epitracheal gland, containing the Inka cells. Importantly, dsRNA-BdCrzR-mediated gene-silencing caused a delay in larval-pupal transition and Pupariation, and this phenomenon agreed with a delayed expression of tyrosine hydroxylase and dopa-decarboxylase genes. We speculate that CrzR-silencing blocked dopamine synthesis, resulting in the inhibition of Pupariation and cuticular melanization. Finally, injection of Crz in head-ligated larvae could rescue the effects. These findings provide a new insight into the roles of Crz signaling pathway components in B. dorsalis and support an important role of CrzR in larval-pupal transition and Pupariation behavior.
