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  Subjects -> BIOLOGY (Total: 3003 journals)
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BIOCHEMISTRY (237 journals)                  1 2 | Last

Showing 1 - 200 of 237 Journals sorted alphabetically
AAPS PharmSciTech     Hybrid Journal   (Followers: 6)
Acetic Acid Bacteria     Open Access   (Followers: 2)
ACS Central Science     Open Access   (Followers: 7)
ACS Chemical Biology     Full-text available via subscription   (Followers: 257)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 18)
Acta Biochimica Polonica     Open Access  
Acta Crystallographica Section D : Biological Crystallography     Hybrid Journal   (Followers: 9)
Acta Crystallographica Section F: Structural Biology Communications     Hybrid Journal   (Followers: 8)
Advances and Applications in Bioinformatics and Chemistry     Open Access   (Followers: 10)
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Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 8)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
African Journal of Biochemistry Research     Open Access   (Followers: 1)
African Journal of Chemical Education     Open Access   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
American Journal of Biochemistry     Open Access   (Followers: 8)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 67)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 14)
American Journal of Polymer Science     Open Access   (Followers: 25)
Amino Acids     Hybrid Journal   (Followers: 8)
Analytical and Bioanalytical Chemistry Research     Open Access  
Analytical Biochemistry     Hybrid Journal   (Followers: 167)
Angiogenesis     Hybrid Journal   (Followers: 3)
Annals of Clinical Biochemistry     Hybrid Journal   (Followers: 8)
Annual Review of Biochemistry     Full-text available via subscription   (Followers: 55)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 44)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 17)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Archives of Biochemistry and Biophysics     Hybrid Journal   (Followers: 20)
Archives of Insect Biochemistry and Physiology     Hybrid Journal  
Archives Of Physiology And Biochemistry     Hybrid Journal   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Bangladesh Journal of Medical Biochemistry     Open Access   (Followers: 3)
BBA Clinical     Open Access  
BBR : Biochemistry and Biotechnology Reports     Open Access   (Followers: 4)
Biocatalysis     Open Access  
Biochemical and Biophysical Research Communications     Hybrid Journal   (Followers: 21)
Biochemical and Molecular Medicine     Full-text available via subscription   (Followers: 4)
Biochemical Compounds     Open Access  
Biochemical Engineering Journal     Hybrid Journal   (Followers: 14)
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Biochemical Journal     Full-text available via subscription   (Followers: 25)
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Biochemical Society Transactions     Full-text available via subscription   (Followers: 4)
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Biochemistry     Full-text available via subscription   (Followers: 305)
Biochemistry & Pharmacology : Open Access     Open Access   (Followers: 3)
Biochemistry & Physiology : Open Access     Open Access  
Biochemistry (Moscow)     Hybrid Journal   (Followers: 4)
Biochemistry (Moscow) Supplement Series A: Membrane and Cell Biology     Hybrid Journal   (Followers: 3)
Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry     Hybrid Journal   (Followers: 3)
Biochemistry and Biophysics Reports     Open Access  
Biochemistry and Cell Biology     Hybrid Journal   (Followers: 14)
Biochemistry and Molecular Biology Education     Hybrid Journal   (Followers: 6)
Biochemistry and Molecular Biology of Fishes     Full-text available via subscription   (Followers: 1)
Biochemistry Research International     Open Access   (Followers: 6)
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids     Hybrid Journal   (Followers: 7)
Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease     Hybrid Journal   (Followers: 14)
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research     Hybrid Journal   (Followers: 9)
Biochimie     Hybrid Journal   (Followers: 7)
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Bioconjugate Chemistry     Full-text available via subscription   (Followers: 30)
BioDrugs     Full-text available via subscription   (Followers: 7)
Bioelectrochemistry     Hybrid Journal   (Followers: 2)
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BioInorganic Reaction Mechanisms     Hybrid Journal   (Followers: 1)
Biokemistri     Open Access  
Biological Chemistry     Partially Free   (Followers: 22)
Biomaterials Research     Open Access   (Followers: 4)
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BioMolecular Concepts     Hybrid Journal   (Followers: 2)
Bioscience, Biotechnology, and Biochemistry     Hybrid Journal   (Followers: 24)
Biosimilars     Open Access   (Followers: 1)
Biotechnology and Applied Biochemistry     Hybrid Journal   (Followers: 45)
Bitácora Digital     Open Access  
BMC Biochemistry     Open Access   (Followers: 14)
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca : Food Science and Technology     Open Access   (Followers: 1)
Carbohydrate Polymers     Hybrid Journal   (Followers: 8)
Cell Biochemistry and Biophysics     Hybrid Journal   (Followers: 6)
Cell Biochemistry and Function     Hybrid Journal   (Followers: 6)
Cellular Physiology and Biochemistry     Open Access   (Followers: 3)
ChemBioChem     Hybrid Journal   (Followers: 7)
Chemical and Biological Technologies for Agriculture     Open Access  
Chemical Biology & Drug Design     Hybrid Journal   (Followers: 20)
Chemical Engineering Journal     Hybrid Journal   (Followers: 45)
Chemical Senses     Hybrid Journal   (Followers: 1)
Chemical Speciation and Bioavailability     Open Access   (Followers: 1)
Chemico-Biological Interactions     Hybrid Journal   (Followers: 3)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 6)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry and Ecology     Hybrid Journal  
ChemTexts     Hybrid Journal  
Clinica Chimica Acta     Hybrid Journal   (Followers: 33)
Clinical Biochemist Reviews     Full-text available via subscription   (Followers: 1)
Clinical Biochemistry     Hybrid Journal   (Followers: 18)
Clinical Chemistry     Full-text available via subscription   (Followers: 68)
Clinical Chemistry and Laboratory Medicine     Hybrid Journal   (Followers: 61)
Clinical Lipidology     Full-text available via subscription   (Followers: 1)
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology     Hybrid Journal   (Followers: 4)
Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 1)
Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology     Hybrid Journal   (Followers: 7)
Comparative Biochemistry and Physiology Part D: Genomics and Proteomics     Hybrid Journal   (Followers: 2)
Comprehensive Biochemistry     Full-text available via subscription   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Current Chemical Biology     Hybrid Journal   (Followers: 2)
Current Medicinal Chemistry     Hybrid Journal   (Followers: 16)
Current Opinion in Chemical Biology     Hybrid Journal   (Followers: 28)
Current Opinion in Lipidology     Hybrid Journal   (Followers: 6)
DNA Barcodes     Open Access  
Doklady Biochemistry and Biophysics     Hybrid Journal   (Followers: 1)
Doklady Chemistry     Hybrid Journal  
Egyptian Journal of Biochemistry and Molecular Biology     Full-text available via subscription  
FABICIB     Open Access  
FEBS Letters     Hybrid Journal   (Followers: 56)
FEBS Open Bio     Open Access   (Followers: 3)
Fish Physiology and Biochemistry     Hybrid Journal   (Followers: 4)
Food & Function     Full-text available via subscription   (Followers: 5)
Foundations of Modern Biochemistry     Full-text available via subscription  
Free Radicals and Antioxidants     Full-text available via subscription   (Followers: 4)
Frontiers in Molecular Biosciences     Open Access   (Followers: 2)
Frontiers in Natural Product Chemistry     Hybrid Journal  
Global Biogeochemical Cycles     Full-text available via subscription   (Followers: 15)
Green Chemistry     Full-text available via subscription   (Followers: 10)
Histochemistry and Cell Biology     Hybrid Journal   (Followers: 5)
Indian Journal of Biochemistry and Biophysics (IJBB)     Open Access   (Followers: 3)
Indian Journal of Clinical Biochemistry     Hybrid Journal   (Followers: 1)
Indonesian Biomedical Journal     Open Access  
Insect Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 3)
International Journal of Biochemistry & Cell Biology     Hybrid Journal   (Followers: 8)
International Journal of Biochemistry and Biophysics     Open Access   (Followers: 1)
International Journal of Biological Chemistry     Open Access   (Followers: 4)
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 6)
International Journal of Food Contamination     Open Access  
International Journal of Plant Physiology and Biochemistry     Open Access   (Followers: 1)
International Journal of Plant Research     Open Access   (Followers: 3)
International Journal of Secondary Metabolite     Open Access   (Followers: 1)
Invertebrate Immunity     Open Access   (Followers: 1)
JBIC Journal of Biological Inorganic Chemistry     Hybrid Journal   (Followers: 4)
Journal of Microbial & Biochemical Technology     Open Access   (Followers: 2)
Journal of Applied Biology & Biotechnology     Open Access   (Followers: 2)
Journal of Bioactive and Compatible Polymers     Hybrid Journal   (Followers: 3)
Journal of Biochemistry     Hybrid Journal   (Followers: 43)
Journal of Biochemistry and Molecular Biology Research     Open Access  
Journal of Biological Chemistry     Full-text available via subscription   (Followers: 198)
Journal of Biomaterials Science, Polymer Edition     Hybrid Journal   (Followers: 9)
Journal of Carbohydrate Chemistry     Hybrid Journal   (Followers: 7)
Journal of Cellular Biochemistry     Hybrid Journal   (Followers: 5)
Journal of Chemical Biology     Hybrid Journal   (Followers: 3)
Journal of Chemical Neuroanatomy     Hybrid Journal  
Journal of Clinical Lipidology     Hybrid Journal   (Followers: 1)
Journal of Comparative Physiology B : Biochemical, Systemic, and Environmental Physiology     Hybrid Journal   (Followers: 4)
Journal of Drug Discovery and Therapeutics     Open Access  
Journal of Enzyme Inhibition and Medicinal Chemistry     Open Access   (Followers: 3)
Journal of Evolutionary Biochemistry and Physiology     Hybrid Journal  
Journal of Food and Drug Analysis     Open Access  
Journal of Forensic Toxicology and Pharmacology     Hybrid Journal   (Followers: 4)
Journal of Inborn Errors of Metabolism and Screening     Open Access  
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 6)
Journal of Medical and Biomedical Sciences     Open Access  
Journal of Medical Biochemistry     Open Access   (Followers: 4)
Journal of Medicine and Biomedical Research     Open Access   (Followers: 1)
Journal of Molecular Biochemistry     Open Access   (Followers: 3)
Journal of Molecular Diagnostics     Hybrid Journal   (Followers: 6)
Journal of Neurochemistry     Hybrid Journal   (Followers: 4)
Journal of Nutritional Biochemistry     Hybrid Journal   (Followers: 7)
Journal of Pediatric Biochemistry     Hybrid Journal   (Followers: 1)
Journal of Peptide Science     Hybrid Journal   (Followers: 22)
Journal of Photochemistry and Photobiology B: Biology     Hybrid Journal   (Followers: 3)
Journal of Physiobiochemical Metabolism     Hybrid Journal   (Followers: 1)
Journal of Physiology and Biochemistry     Hybrid Journal   (Followers: 3)
Journal of Plant Biochemistry and Biotechnology     Hybrid Journal   (Followers: 6)
Journal of Steroid Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 2)
Journal of Virology & Antiviral Research     Hybrid Journal   (Followers: 5)
Journal of Wood Chemistry and Technology     Hybrid Journal   (Followers: 10)
La Rivista Italiana della Medicina di Laboratorio - Italian Journal of Laboratory Medicine     Hybrid Journal  
Lab on a Chip     Full-text available via subscription   (Followers: 36)
Marine Chemistry     Hybrid Journal   (Followers: 6)
Methods in Enzymology     Full-text available via subscription   (Followers: 11)
Molecular and Biochemical Parasitology     Hybrid Journal   (Followers: 2)
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Molecular Aspects of Medicine     Hybrid Journal   (Followers: 3)
Molecular Informatics     Hybrid Journal   (Followers: 6)
Molecular inhibitors in targeted therapy     Open Access  
Moscow University Chemistry Bulletin     Hybrid Journal   (Followers: 1)
Mycologia     Hybrid Journal  
Mycology : An International Journal on Fungal Biology     Hybrid Journal   (Followers: 5)
Natural Products and Bioprospecting     Open Access   (Followers: 2)
Nature Chemical Biology     Full-text available via subscription   (Followers: 72)
Nature Communications     Open Access   (Followers: 192)
Neurosignals     Open Access  
NOVA     Open Access  
Novelty in Biomedicine     Open Access  
OA Biochemistry     Open Access   (Followers: 1)
OA Inflammation     Open Access  
Ocean Acidification     Open Access   (Followers: 4)
Organic & Biomolecular Chemistry     Full-text available via subscription   (Followers: 89)

        1 2 | Last

Journal Cover Insect Biochemistry and Molecular Biology
  [SJR: 1.957]   [H-I: 86]   [3 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0965-1748
   Published by Elsevier Homepage  [3043 journals]
  • Serpin-9 and -13 regulate hemolymph proteases during immune responses of
           Manduca sexta
    • Authors: Yan He; Yang Wang; Picheng Zhao; Subrahmanyam Rayaprolu; Xiuhong Wang; Xiaolong Cao; Haobo Jiang
      Pages: 71 - 81
      Abstract: Publication date: November 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 90
      Author(s): Yan He, Yang Wang, Picheng Zhao, Subrahmanyam Rayaprolu, Xiuhong Wang, Xiaolong Cao, Haobo Jiang
      Serpins are a superfamily of proteins, most of which inhibit cognate serine proteases by forming inactive acyl-enzyme complexes. In the tobacco hornworm Manduca sexta, serpin-1, -3 through -7 negatively regulate a hemolymph serine protease system that activates precursors of the serine protease homologs (SPHs), phenoloxidases (POs), Spätzles, and other cytokines. Here we report the cloning and characterization of M. sexta serpin-9 and -13. Serpin-9, a 402-residue protein most similar to Drosophila Spn77Ba, has R366 at the P1 position right before the cleavage site; Serpin-13, a 444-residue ortholog of Drosophila Spn28Dc, is longer than the other seven serpins and has R410 as the P1 residue. Both serpins are mainly produced in fat body and secreted into plasma to function. While their mRNA and protein levels were not up-regulated upon immune challenge, they blocked protease activities and affected proPO activation in hemolymph. Serpin-9 inhibited human neutrophil elastase, cathepsin G, trypsin, and chymotrypsin to different extents; serpin-13 reduced trypsin activity to approximately 10% at a molar ratio of 4:1 (serpin: enzyme). Serpin-9 was cleaved at Arg366 by the enzymes with different specificity, but serpin-13 had four P1 sites (Arg410 for trypsin-like proteases, Gly406 and Ala409 for the elastase and Thr404 for cathepsin G). Supplementation of induced cell-free hemolymph (IP, P for plasma) with recombinant serpin-9 did not noticeably affect proPO activation, but slightly reduced the PO activity increase after 0–50% ammonium sulfate fraction of the IP had been elicited by bacteria. In comparison, addition of recombinant serpin-13 significantly inhibited proPO activation in IP and the suppression was stronger in the fraction of IP. Serpin-9- and -13-containing protein complexes were isolated from IP using their antibodies. Hemolymph protease-1 precursor (proHP1), HP6 and HP8 were found to be associated with serpin-9, whereas proHP1, HP2 and HP6 were pulled downed with serpin-13. These results indicate that both serpins regulate immune proteases in hemolymph of M. sexta larvae.
      Graphical abstract image

      PubDate: 2017-10-14T08:17:32Z
      DOI: 10.1016/j.ibmb.2017.09.015
      Issue No: Vol. 90 (2017)
       
  • Timed Knickkopf function is essential for wing cuticle formation in
           Drosophila melanogaster
    • Authors: Kaixia Li; Xubo Zhang; Ying Zuo; Weimin Liu; Jianzhen Zhang; Bernard Moussian
      Pages: 1 - 10
      Abstract: Publication date: October 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 89
      Author(s): Kaixia Li, Xubo Zhang, Ying Zuo, Weimin Liu, Jianzhen Zhang, Bernard Moussian
      The insect cuticle is an extracellular matrix that consists of the polysaccharide chitin, proteins, lipids and organic molecules that are arranged in distinct horizontal layers. In Drosophila melanogaster, these layers are not formed sequentially, but, at least partially, at the same time. Timing of the underlying molecular mechanisms is conceivably crucial for cuticle formation. To study this issue, we determined the time period during which the function of Knickkopf (Knk), a key factor of chitin organization, is required for wing cuticle differentiation in D. melanogaster. Although knk is expressed throughout metamorphosis, we demonstrate that its expression 30 h prior and 48 h after pupariation is essential for correct wing cuticle formation. In other words, expression beyond this period is futile. Importantly, manipulation of Knk expression during this time causes wing bending suggesting an effect of Knk amounts on the physical properties of the wing cuticle. Manipulation of Knk expression also interferes with the structure and function of the cuticle surface. First, we show that the shape of surface nano-structures depends on the expression levels of knk. Second, we find that cuticle impermeability is compromised in wings with reduced knk expression. In summary, despite the extended supply of Knk during metamorphosis, controlled amounts of Knk are important for correct wing cuticle differentiation and function in a concise period of time.
      Graphical abstract image

      PubDate: 2017-08-25T17:51:06Z
      DOI: 10.1016/j.ibmb.2017.08.003
      Issue No: Vol. 89 (2017)
       
  • Active subsite properties, subsite residues and targeting to lysosomes or
           midgut lumen of cathepsins L from the beetle Tenebrio molitor
    • Authors: Ticiane F. Damasceno; Renata O. Dias; Juliana R. de Oliveira; Roberto K. Salinas; Maria A. Juliano; Clelia Ferreira; Walter R. Terra
      Pages: 17 - 30
      Abstract: Publication date: October 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 89
      Author(s): Ticiane F. Damasceno, Renata O. Dias, Juliana R. de Oliveira, Roberto K. Salinas, Maria A. Juliano, Clelia Ferreira, Walter R. Terra
      Cathepsins L are the major digestive peptidases in the beetle Tenebrio molitor. Two digestive cathepsins L (TmCAL2 and TmCAL3) from it had their 3D structures solved. The aim of this paper was to study in details TmCAL3 specificity and properties and relate them to its 3D structure. Recombinant TmCAL3 was assayed with 64 oligopeptides with different amino acid replacements in positions P2, P1, P1′ and P2'. Results showed that TmCAL3 S2 specificity differs from the human enzyme and that its specificities also explain why on autoactivation two propeptide residues remain in the enzyme. Data on free energy of binding and of activation showed that S1 and S2′ are mainly involved in substrate binding, S1′ acts in substrate binding and catalysis, whereas S2 is implied mainly in catalysis. Enzyme subsite residues were identified by docking with the same oligopeptide used for kinetics. The subsite hydrophobicities were calculated from the efficiency of hydrolysis of different amino acid replacements in the peptide and from docking data. The results were closer for S1 and S2′ than for S1' and S2, indicating that the residue subsites that were more involved in transition state binding are different from those binding the substrate seen in docking. Besides TmCAL1-3, there are nine other cathepsins L, most of them more expressed at midgut. They are supposed to be directed to lysosomes by a Drosophila-like Lerp receptor and/or motifs in their prodomains. The mannose 6-phosphate lysosomal sorting machinery is absent from T. molitor transcriptome. Cathepsin L direction to midgut contents seems to depend on overexpression.
      Graphical abstract image

      PubDate: 2017-09-03T19:53:40Z
      DOI: 10.1016/j.ibmb.2017.08.004
      Issue No: Vol. 89 (2017)
       
  • TmSR-C, scavenger receptor class C, plays a pivotal role in antifungal and
           antibacterial immunity in the coleopteran insect Tenebrio molitor
    • Authors: Soo Gon Kim; Yong Hun Jo; Jeong Hwan Seong; Ki Beom Park; Mi Young Noh; Jun Ho Cho; Hye Jin Ko; Chang Eun Kim; Hamisi Tindwa; Bharat Bhusan Patnaik; In Seok Bang; Yong Seok Lee; Yeon Soo Han
      Pages: 31 - 42
      Abstract: Publication date: Available online 1 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Soo Gon Kim, Yong Hun Jo, Jeong Hwan Seong, Ki Beom Park, Mi Young Noh, Jun Ho Cho, Hye Jin Ko, Chang Eun Kim, Hamisi Tindwa, Bharat Bhusan Patnaik, In-Seok Bang, Yong Seok Lee, Yeon Soo Han
      Scavenger receptors (SRs) constitute a family of membrane-bound receptors that bind to multiple ligands. The SR family of proteins is involved in removing cellular debris, oxidized low-density lipoproteins, and pathogens. Specifically, class C scavenger receptors (SR-C) have also been reported to be involved in phagocytosis of gram-positive and -negative bacteria in Drosophila and viruses in shrimp. However, reports are unavailable regarding the role of SR-C in antifungal immune mechanisms in insects. In this study, a full-length Tenebrio molitor SR-C (TmSR-C) sequence was obtained by 5′- and 3′-Rapid amplification of cDNA ends-polymerase chain reaction (RACE-PCR). The TmSR-C full-length cDNA comprised 1671 bp with 5′- and 3′-untranslated regions of 23- and 107-bp, respectively. TmSR-C encodes a putative protein of 556 amino acid residues that is constitutively expressed in all tissues of late instar larvae and 2-day-old adults, with the highest transcript levels observed in hemocytes of larvae and adults. TmSR-C mRNA showed a 2.5-fold and 3-fold increase at 24 and 6 h after infection with Candida albicans and β-glucan, respectively. Immunoassay with TmSR-C polyclonal antibody showed induction of the putative protein in the cytosols of hemocytes at 3 h after inoculation of C. albicans. RNA interference (RNAi)-based gene silencing and phagocytosis assays were used to understand the role of TmSR-C in antifungal immunity. Silencing of TmSR-C transcripts reduced the survivability of late instar larvae at 2 days post-inoculation of C. albicans, Escherichia coli, or Staphylococcus aureus. Furthermore, in TmSR-C-silenced larvae, there was a decline in the rate of microorganism phagocytosis. Taken together, results of this study suggest that TmSR-C plays a pivotal role in phagocytosing not only fungi but also gram-negative and -positive bacteria in T. molitor.
      Graphical abstract image

      PubDate: 2017-09-03T19:53:40Z
      DOI: 10.1016/j.ibmb.2017.08.007
      Issue No: Vol. 89 (2017)
       
  • FOXA transcriptional factor modulates insect susceptibility to Bacillus
           thuringiensis Cry1Ac toxin by regulating the expression of toxin-receptor
           ABCC2 and ABCC3 genes
    • Authors: Jianghuai Li; Yuemin Ma; Wanli Yuan; Yutao Xiao; Chenxi Liu; Jia Wang; Jianxin Peng; Rong Peng; Mario Soberón; Alejandra Bravo; Yongbo Yang; Kaiyu Liu
      Pages: 1 - 11
      Abstract: Publication date: Available online 21 July 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Jianghuai Li, Yuemin Ma, Wanli Yuan, Yutao Xiao, Chenxi Liu, Jia Wang, Jianxin Peng, Rong Peng, Mario Soberón, Alejandra Bravo, Yongbo Yang, Kaiyu Liu
      Cry toxins produced by Bacillus thuringiensis (Bt) are insecticidal proteins widely used in insect control. Recently, it was shown that ATP-binding cassette transporter proteins (ABC) such as ABCC2, ABCC3, ABCG1 and ABCA2 are implicated in the insecticidal action of Cry toxins as putative receptors. However, the transcriptional regulators involved in the expression of ABC transporter genes remain unknown. Sequence analysis of promoter regions of ABCC2 gene from Helicoverpa armigera and ABCC3 gene from Spodoptera litura Sl-HP cultured cells, revealed the potential participation of Forkhead box protein A (FOXA), a transcription factor that regulates the expression of genes through remodeling chromatin. To determine if FOXA was involved in regulating expression of ABCC2 and ABCC3 genes, the expression of FOXA, ABCC2 and ABCC3 was compared in Sl-HP cells that are sensitive to Cry1Ac toxin with those on S. frugiperda Sf9 cells that are not sensitive to the toxin. Expression levels of those genes were significantly higher in Sl-HP than in Sf9 cells. Transient expression of FOXA in Sf9 cells activated ABCC2 and ABCC3 transcription, which directly correlated with enhanced Cry1Ac-susceptibility in these cells. Silencing of FOXA gene expression by RNAi in H. armigera larvae resulted in a decreased expression of ABCC2 and ABCC3 without affecting expression of other Cry toxin receptor genes such as alkaline phosphatase, aminopeptidase or cadherin. Silencing of FOXA gene expression also resulted in a Cry1Ac-tolerant phenotype since lower mortality and higher pupation rate were observed in diet containing Cry1Ac protoxin in comparison with the control group. These results demonstrate that FOXA up-regulates expression of the Cry1Ac-toxin receptor ABCC2 and ABCC3 genes, and that lower FOXA expression correlates with tolerance to Cry toxin in cell lines and in lepidopteran larvae.
      Graphical abstract image

      PubDate: 2017-07-26T13:33:28Z
      DOI: 10.1016/j.ibmb.2017.07.004
      Issue No: Vol. 88 (2017)
       
  • Wolbachia infection in Aedes aegypti mosquitoes alters blood meal
           excretion and delays oviposition without affecting trypsin activity
    • Authors: Sofia Pimenta de Oliveira; Caroline Dantas de Oliveira; Mauricio Roberto Viana Sant’Anna; Heverton Leandro Carneiro Dutra; Eric Pearce Caragata; Luciano Andrade Moreira
      Pages: 65 - 74
      Abstract: Publication date: August 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 87
      Author(s): Sofia Pimenta de Oliveira, Caroline Dantas de Oliveira, Mauricio Roberto Viana Sant’Anna, Heverton Leandro Carneiro Dutra, Eric Pearce Caragata, Luciano Andrade Moreira
      Blood feeding in Aedes aegypti is essential for reproduction, but also permits the mosquito to act as a vector for key human pathogens such as the Zika and dengue viruses. Wolbachia pipientis is an endosymbiotic bacterium that can manipulate the biology of Aedes aegypti mosquitoes, making them less competent hosts for many pathogens. Yet while Wolbachia affects other aspects of host physiology, it is unclear whether it influences physiological processes associated with blood meal digestion. To that end, we examined the effects of wMel Wolbachia infection in Ae. aegypti, on survival post-blood feeding, blood meal excretion, rate of oviposition, expression levels of key genes involved in oogenesis, and activity levels of trypsin blood digestion enzymes. We observed that wMel infection altered the rate and duration of blood meal excretion, delayed the onset of oviposition and was associated with a greater number of eggs being laid later. wMel-infected Ae. aegypti also had lower levels of key yolk protein precursor genes necessary for oogenesis. However, all of these effects occurred without a change in trypsin activity. These results suggest that Wolbachia infection may disrupt normal metabolic processes associated with blood feeding and reproduction in Ae. aegypti.
      Graphical abstract image

      PubDate: 2017-07-01T03:03:53Z
      DOI: 10.1016/j.ibmb.2017.06.010
      Issue No: Vol. 87 (2017)
       
  • nanos-Driven expression of piggyBac transposase induces mobilization of a
           synthetic autonomous transposon in the malaria vector mosquito, Anopheles
           stephensi
    • Authors: Vanessa M. Macias; Alyssa J. Jimenez; Bianca Burini-Kojin; David Pledger; Nijole Jasinskiene; Celine Hien Phong; Karen Chu; Aniko Fazekas; Kelcie Martin; Osvaldo Marinotti; Anthony A. James
      Pages: 81 - 89
      Abstract: Publication date: August 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 87
      Author(s): Vanessa M. Macias, Alyssa J. Jimenez, Bianca Burini-Kojin, David Pledger, Nijole Jasinskiene, Celine Hien Phong, Karen Chu, Aniko Fazekas, Kelcie Martin, Osvaldo Marinotti, Anthony A. James
      Transposons are a class of selfish DNA elements that can mobilize within a genome. If mobilization is accompanied by an increase in copy number (replicative transposition), the transposon may sweep through a population until it is fixed in all of its interbreeding members. This introgression has been proposed as the basis for drive systems to move genes with desirable phenotypes into target species. One such application would be to use them to move a gene conferring resistance to malaria parasites throughout a population of vector mosquitos. We assessed the feasibility of using the piggyBac transposon as a gene-drive mechanism to distribute anti-malarial transgenes in populations of the malaria vector, Anopheles stephensi. We designed synthetic gene constructs that express the piggyBac transposase in the female germline using the control DNA of the An. stephensi nanos orthologous gene linked to marker genes to monitor inheritance. Two remobilization events were observed with a frequency of one every 23 generations, a rate far below what would be useful to drive anti-pathogen transgenes into wild mosquito populations. We discuss the possibility of optimizing this system and the impetus to do so.
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      PubDate: 2017-07-10T07:34:33Z
      DOI: 10.1016/j.ibmb.2017.06.014
      Issue No: Vol. 87 (2017)
       
  • Cry46Ab from Bacillus thuringiensis TK-E6 is a new mosquitocidal toxin
           with aerolysin-type architecture
    • Authors: Tohru Hayakawa; Akira Sakakibara; Sho Ueda; Yoshinao Azuma; Toru Ide; So Takebe
      Pages: 100 - 106
      Abstract: Publication date: August 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 87
      Author(s): Tohru Hayakawa, Akira Sakakibara, Sho Ueda, Yoshinao Azuma, Toru Ide, So Takebe
      Cry46Ab is a Cry toxin derived from Bacillus thuringiensis TK-E6. Cry46Ab is not significantly homologous to other mosquitocidal Cry or Cyt toxins and is classified as an aerolysin-type pore-forming toxin based on structural similarity. In this study, the potency of Cry46Ab was assessed for its potential application to mosquito control. A synthetic Cry46Ab gene, cry46Ab-S1, was designed to produce recombinant Cry46Ab as a glutathione-S-transferase fusion in Escherichia coli. Recombinant Cry46Ab showed apparent toxicity to Culex pipiens larvae, with a 50% lethal dose of 1.02 μg/ml. In an artificial lipid bilayer, Cry46Ab activated by trypsin caused typical current transitions between open and closed states, suggesting it functions as a pore-forming toxin similar to other Cry and Cyt toxins. The single-channel conductance was 103.3 ± 4.1 pS in 150 mM KCl. Co-administration of recombinant Cry46Ab with other mosquitocidal Cry toxins, especially the combination of Cry4Aa and Cry46Ab, resulted in significant synergistic toxicity against C. pipiens larvae. Co-administration of multiple toxins exhibiting different modes of action is believed to prevent the onset of resistance in insects. Our data, taken in consideration with the differences in its structure, suggest that Cry46Ab could be useful in not only reducing resistance levels but also improving the insecticidal activity of Bt-based bio-insecticides.
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      PubDate: 2017-07-10T07:34:33Z
      DOI: 10.1016/j.ibmb.2017.06.015
      Issue No: Vol. 87 (2017)
       
  • Biochemical identification of residues that discriminate between
           3,4-dihydroxyphenylalanine decarboxylase and
           3,4-dihydroxyphenylacetaldehyde synthase-mediated reactions
    • Authors: Jing Liang; Haizhen Ding; Qian Han; Jianyong Li
      Abstract: Publication date: Available online 14 October 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Jing Liang, Haizhen Ding, Qian Han, Jianyong Li
      In available insect genomes, there are several L-3,4-dihydroxyphenylalanine (L-dopa) decarboxylase (DDC)-like or aromatic amino acid decarboxylase (AAAD) sequences. This contrasts to those of mammals whose genomes contain only one DDC. Our previous experiments established that two DDC-like proteins from Drosophila actually mediate a complicated decarboxylation-oxidative deamination process of dopa in the presence of oxygen, leading to the formation of 3,4-dihydroxyphenylacetaldehyde (DHPA), CO2, NH3, and H2O2. This contrasts to the typical DDC-catalyzed reaction, which produces CO2 and dopamine. These DDC-like proteins were arbitrarily named DHPA synthases based on their critical role in insect soft cuticle formation. Establishment of reactions catalyzed by these AAAD-like proteins solved a puzzle that perplexed researchers for years, but to tell a true DHPA synthase from a DDC in the insect AAAD family remains problematic due to high sequence similarity. In this study, we performed extensive structural and biochemical comparisons between DHPA synthase and DDC. These comparisons identified several target residues potentially dictating DDC-catalyzed and DHPA synthase-catalyzed reactions, respectively. Comparison of DHPA synthase homology models with crystal structures of typical DDC proteins, particularly residues in the active sites, provided further insights for the roles these identified target residues play. Subsequent site-directed mutagenesis of the tentative target residues and activity evaluations of their corresponding mutants determined that active site His192 and Asn192 are essential signature residues for DDC- and DHPA synthase-catalyzed reactions, respectively. Oxygen is required in DHPA synthase-mediated process and this oxidizing agent is reduced to H2O2 in the process. Biochemical assessment established that H2O2, formed in DHPA synthase-mediated process, can be reused as oxidizing agent and this active oxygen species is reduced to H2O; thereby avoiding oxidative stress by H2O2. Results of our structural and functional analyses provide a reasonable explanation of mechanisms involved in DHPA synthase-mediated reactions. Based on the key active site residue Asn192, identified in Drosophila DHPA synthase, we were able to distinguish all available insect DHPA synthases from DDC sequences primarily.
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      PubDate: 2017-10-14T08:17:32Z
      DOI: 10.1016/j.ibmb.2017.10.001
       
  • Spider acetylcholine binding proteins: An alternative model to study the
           interaction between insect nAChRs and neonicotinoids
    • Authors: Haibo Bao; Xiangkun Meng; Zewen Liu
      Abstract: Publication date: Available online 6 October 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Haibo Bao, Xiangkun Meng, Zewen Liu
      Acetylcholine binding proteins (AChBPs) are homologs of extracellular domains of nicotinic acetylcholine receptors (nAChRs) and serve as models for studies on nAChRs. Particularly, studies on invertebrate nAChRs that are limited due to difficulties in their heterologous expression have benefitted from the discovery of AChBPs. Thus far, AChBPs have been characterized only in aquatic mollusks, which have shown low sensitivity to neonicotinoids, the insecticides targeting insect nAChRs. However, AChBPs were also found in spiders based on the sequence and tissue expression analysis. Here, we report five AChBP subunits in Pardosa pseudoannulata, a predator enemy against rice insect pests. Spider AChBP subunits shared higher sequence similarities with nAChR subunits of both insects and mammals compared with mollusk AChBP subunits. The AChBP1 subunit of P. pseudoannulata (Pp-AChBP) was then expressed in Sf9 cells. The Ls-AChBP from Lymnaea stagnalis was also expressed for comparison. In both AChBPs, one ligand site per subunit was present at each interface between two adjacent subunits. Neonicotinoids had higher affinities (7.9–18.4 times based on K d or K i values) for Pp-AChBP than for Ls-AChBP, although epibatidine and α-bungarotoxin showed higher affinities for Ls-AChBP. These results indicate that spider AChBP could be used as an alternative model to study the interaction between insect nAChRs and neonicotinoids.
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      PubDate: 2017-10-11T07:48:04Z
      DOI: 10.1016/j.ibmb.2017.09.014
       
  • Expressional divergences of two desaturase genes determine the opposite
           ratios of two sex pheromone components in Helicoverpa armigera and
           Helicoverpa assulta
    • Authors: Rui-Ting Li; Chao Ning; Ling-Qiao Huang; Jun-Feng Dong; Xianchun Li; Chen-Zhu Wang
      Abstract: Publication date: Available online 3 October 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Rui-Ting Li, Chao Ning, Ling-Qiao Huang, Jun-Feng Dong, Xianchun Li, Chen-Zhu Wang
      The sympatric closely related species Helicoverpa armigera and Helicoverpa assulta use 97:3 and 7:93 of (Z)-11-hexadecenal and (Z)-9-hexadecenal, respectively, as their sex pheromone to find/locate correct sex mates. Moreover, (Z)-11-hexadecenyl alcohol and (Z)-9-hexadecenyl alcohol are more abundant in the pheromone gland of H. assulta than in that of H. armigera. To clarify the molecular basis of these differences, we sequenced the pheromone gland transcriptomes of the two species and compared the expression patterns of the candidate enzyme genes involved in the pheromone biosynthetic pathways by FPKM values and quantitative RT-PCR analysis. We found that the desaturase gene LPAQ expressed about 70 times higher in H. armigera than in H. assulta, whereas another desaturase gene NPVE expressed about 60 times higher in H. assulta than in H. armigera. We also observed significantly higher expression of the fatty acyl reductase (FAR) gene FAR1 and the aldehyde reductase (AR) gene AR3 in H. assulta than in H. armigera. Examination of the pheromone glands of the backcross offspring of their hybrids to H. assulta showed a positive linear correlation between the expression level of LPAQ and the amount of Z11-16:Ald and between the expression level of NPVE and the amount of Z9-16:Ald in the pheromone glands. Taken together, these data demonstrate that the expressional divergence of LPAQ and NPVE determine the opposite sex pheromone component ratios in the two species and the divergent expression of FAR1 and AR3 may account for the greater accumulation of alcohols in the pheromone gland of H. assulta.
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      PubDate: 2017-10-04T09:30:33Z
      DOI: 10.1016/j.ibmb.2017.09.016
       
  • Functions and substrates of NEDDylation during cell cycle in the silkworm,
           Bombyx mori
    • Authors: Zhiqing Li; Qixin Cui; Xiaoyan Wang; Bingqian Li; Dongchao Zhao; Qingyou Xia; Ping Zhao
      Abstract: Publication date: Available online 28 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Zhiqing Li, Qixin Cui, Xiaoyan Wang, Bingqian Li, Dongchao Zhao, Qingyou Xia, Ping Zhao
      NEDDylation, a post-translational modification mediated by the conjugation of the ubiquitin-like protein Nedd8 to specific substrates, is an essential biological process that regulates cell cycle progression in eukaryotes. Here, we report the conservation of NEDDylation machinery and NEDDylated proteins in the silkworm, Bombyx mori. We have identified all the components necessary for reversible NEDDylation in the silkworm including Nedd8, E1, E2, E3, and deNEDDylation enzymes. By the approach of RNAi-mediated gene silencing, it was shown that knockdown of BmNedd8 and the conjugating enzymes decreased the global level of NEDDylation, while knockdown of deNEDDylation enzymes increased the prevalence of this modification in cultured silkworm cells. Moreover, the lack of the NEDDylation system caused cell cycle arrest at the G2/M phase and resulted in defects in chromosome congression and segregation. Using the wild-type and mutants of BmNedd8, we identified the specific substrates of BmNedd8, which are involved in the regulation for many cellular processes, including ribosome biogenesis, spliceosome structure, spindle formation, metabolism, and RNA biogenesis. This clearly demonstrates that the NEDDylation system is able to control multiple pathways in the silkworm. Altogether, the information on the functions and substrates of the NEDDylation system presented here could provide a basis for future investigations of protein NEDDylation and its regulatory mechanism on cell cycle progression in the silkworm.
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      PubDate: 2017-10-04T09:30:33Z
      DOI: 10.1016/j.ibmb.2017.09.013
       
  • Accumulation of dsRNA in endosomes contributes to inefficient RNA
           interference in the fall armyworm, Spodoptera frugiperda
    • Authors: June-Sun Yoon; Dhandapani Gurusamy; Subba Reddy Palli
      Abstract: Publication date: Available online 23 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): June-Sun Yoon, Dhandapani Gurusamy, Subba Reddy Palli
      RNA interference (RNAi) efficiency varies among insects studied. The barriers for successful RNAi include the presence of double-stranded ribonucleases (dsRNase) in the lumen and hemolymph that could potentially digest double-stranded RNA (dsRNA) and the variability in the transport of dsRNA into and within the cells. We recently showed that the dsRNAs are transported into lepidopteran cells, but they are not processed into small interference RNAs (siRNAs) because they are trapped in acidic bodies. In the current study, we focused on the identification of acidic bodies in which dsRNAs accumulate in Sf9 cells. Time-lapse imaging studies showed that dsRNAs enter Sf9 cells and accumulate in acidic bodies within 20 min after their addition to the medium. CypHer-5E-labeled dsRNA also accumulated in the midgut and fat body dissected from Spodoptera frugiperda larvae with similar patterns observed in Sf9 cells. Pharmacological inhibitor assays showed that the dsRNAs use clathrin receptor-mediated endocytosis pathway for transport into the cells. We investigated the potential dsRNA accumulation sites employing LysoTracker and double labeling experiments using the constructs to express a fusion of green fluorescence protein with early or late endosomal marker proteins and CypHer-5E-labeled dsRNA. Interestingly, CypHer-5E-labeled dsRNA accumulated predominantly in early and late endosomes. These data suggest that entrapment of internalized dsRNA in endosomes is one of the major factors contributing to inefficient RNAi response in lepidopteran insects.
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      PubDate: 2017-09-27T08:57:22Z
      DOI: 10.1016/j.ibmb.2017.09.011
       
  • Cap n collar transcription factor regulates multiple genes coding for
           proteins involved in insecticide detoxification in the red flour beetle,
           Tribolium castaneum
    • Authors: Megha Kalsi; Subba Reddy Palli
      Abstract: Publication date: Available online 23 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Megha Kalsi, Subba Reddy Palli
      In invertebrates, a heterodimer of xenobiotic transcription factors, cap n collar C isoform (CncC) and muscle aponeurosis fibromatosis (Maf) mediate cellular defense. In insects, these proteins regulate expression of genes involved in insecticide detoxification. In the current study, we performed sequencing of cDNA copied from RNA isolated from Tribolium castaneum pyrethroid resistant strain (QTC279) beetles injected with CncC or green fluorescence protein (GFP, control) dsRNA. Differential expression analysis of sequences identified 662 genes that showed a decrease and 91 genes that showed an increase in expression (p value ≤ 0.01 and log2 fold change of ≥ 1.5) in CncC knockdown insects when compared to their expression in control insects. We selected a subset of 27 downregulated genes and verified their differential expression using qRT-PCR. This subset of 27 genes included 21 genes with a predicted function in xenobiotic detoxification. RNAi and insecticide bioassays were employed to study the function of six of these genes coding for CYP4G7, CYP4G14, GST-1 and four ABC transporters, ABCA-UB, ABCA-A1 and ABCA-A1L and ABCA-9B involved in all three phases of insecticide detoxification. These data suggest that CncC regulates genes coding for proteins involved in detoxification of insecticides.
      Graphical abstract image

      PubDate: 2017-09-27T08:57:22Z
      DOI: 10.1016/j.ibmb.2017.09.009
       
  • Leptinotarsa hormone receptor 4 (HR4) tunes ecdysteroidogenesis and
           mediates 20-hydroxyecdysone signaling during larval-pupal metamorphosis
    • Authors: Qing-Yu Xu; Qing-Wei Meng; Pan Deng; Wen-Chao Guo; Guo-Qing Li
      Abstract: Publication date: Available online 22 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Qing-Yu Xu, Qing-Wei Meng, Pan Deng, Wen-Chao Guo, Guo-Qing Li
      Hormone receptor 4 (HR4) is involved in the regulation of 20-hydroxyecdysone (20E) biosynthesis and the mediation of 20E signaling during larval-pupal transition in a holometabolan Drosophila melanogaster, whereas it acts as a repressor in 20E-responsive transcriptional cascade in a hemimetabolan, Blattella germanica. Here we characterized two HR4 splicing variants, LdHR4X1 and LdHR4X2, in a coleopteran Leptinotarsa decemlineata. LdHR4X1 was highly expressed in the prothoracic gland and epidermis while LdHR4X2 was abundantly transcribed in the nervous system. In vivo results showed that both prothoracicotropic hormone and 20E pathways transcriptionally regulated LdHR4, in an isoform-dependent pattern. RNA interference of LdHR4 at the final (fourth) larval instar, in contrast to the second- and third-instar periods, enhanced the expression of two ecdysteroidogenesis genes, increased 20E titer, upregulated transcription of five 20E-response genes, and reduced the mRNA level of Fushi tarazu-factor 1 (FTZ-F1). As a result, the fourth-instar LdHR4 RNAi larvae exhibited accelerated development and reduced body weight. Moreover, knockdown of LdHR4 at the fourth instar resulted in larval lethality and impaired pupation. Feeding of pyriproxyfen (a mimic of juvenile hormone) or silencing of a juvenile hormone degrading enzyme gene restored the normal course of ecdysteroidogenesis, duration of larval development, and body weight in fourth-instar LdHR4 RNAi larvae. The treatment partially suppressed the larval mortality but not the failure to pupate. The dual role of HR4 during larval-pupal metamorphosis appears to be evolutionarily conserved among holometabolans.
      Graphical abstract image

      PubDate: 2017-09-27T08:57:22Z
      DOI: 10.1016/j.ibmb.2017.09.012
       
  • A new Drosophila octopamine receptor responds to serotonin
    • Authors: Yi-xiang Qi; Gang Xu; Gui-xiang Gu; Fen Mao; Gong-yin Ye; Weiwei Liu; Jia Huang
      Abstract: Publication date: Available online 21 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yi-xiang Qi, Gang Xu, Gui-xiang Gu, Fen Mao, Gong-yin Ye, Weiwei Liu, Jia Huang
      As the counterparts of the vertebrate adrenergic transmitters, octopamine and tyramine are important physiological regulators in invertebrates. They control and modulate many physiological and behavioral functions in insects. In this study, we reported the pharmacological properties of a new α2-adrenergic-like octopamine receptor (CG18208) from Drosophila melanogaster, named DmOctα2R. This new receptor gene encodes two transcripts by alternative splicing. The long isoform DmOctα2R-L differs from the short isoform DmOctα2R-S by the presence of an additional 29 amino acids within the third intracellular loop. When heterologously expressed in mammalian cell lines, both receptors were activated by octopamine, tyramine, epinephrine and norepinephrine, resulting in the inhibition of cAMP production in a dose-dependent manner. The long form is more sensitive to the above ligands than the short form. The adrenergic agonists naphazoline, tolazoline and clonidine can stimulate DmOctα2R as full agonists. Surprisingly, serotonin and serotoninergic agonists can also activate DmOctα2R. Several tested adrenergic antagonists and serotonin antagonists blocked the action of octopamine or serotonin on DmOctα2R. The data presented here reported an adrenergic-like G protein-coupled receptor activated by serotonin, suggesting that the neurotransmission and neuromodulation in the nervous system could be more complex than previously thought.
      Graphical abstract image

      PubDate: 2017-09-27T08:57:22Z
      DOI: 10.1016/j.ibmb.2017.09.010
       
  • The microRNA ame-miR-279a regulates sucrose responsiveness of forager
           honey bees (Apis mellifera)
    • Authors: Fang Liu; Tengfei Shi; Wei Yin; Xin Su; Lei Qi; Zachary Y. Huang; Shaowu Zhang; Linsheng Yu
      Abstract: Publication date: Available online 20 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Fang Liu, Tengfei Shi, Wei Yin, Xin Su, Lei Qi, Zachary Y. Huang, Shaowu Zhang, Linsheng Yu
      Increasing evidence demonstrates that microRNAs (miRNA) play an important role in the regulation of animal behaviours. Honey bees (Apis mellifera) are eusocial insects, with honey bee workers displaying age-dependent behavioural maturation. Many different miRNAs have been implicated in the change of behaviours in honey bees and ame-miR-279a was previously shown to be more highly expressed in nurse bee heads than in those of foragers. However, it was not clear whether this difference in expression was associated with age or task performance. Here we show that ame-miR-279a shows significantly higher expression in the brains of nurse bees relative to forager bees regardless of their ages, and that ame-miR-279a is primarily localized in the Kenyon cells of the mushroom body in both foragers and nurses. Overexpression of ame-miR-279a attenuates the sucrose responsiveness of foragers, while its absence enhances their sucrose responsiveness. Lastly, we determined that ame-miR-279a directly target the mRNA of Mblk-1. These findings suggest that ame-miR-279a plays important roles in regulating honey bee division of labour.
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      PubDate: 2017-09-27T08:57:22Z
      DOI: 10.1016/j.ibmb.2017.09.008
       
  • Maternal provision of transformer-2 is required for female development and
           embryo viability in the wasp Nasonia vitripennis
    • Authors: Elzemiek Geuverink; Anna H. Rensink; Inge Rondeel; Leo W. Beukeboom; Louis van de Zande; Eveline C. Verhulst
      Abstract: Publication date: Available online 18 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Elzemiek Geuverink, Anna H. Rensink, Inge Rondeel, Leo W. Beukeboom, Louis van de Zande, Eveline C. Verhulst
      In insect sex determination a primary signal starts the genetic sex determination cascade that, in most insect orders, is subsequently transduced down the cascade by a transformer (tra) ortholog. Only a female-specifically spliced tra mRNA yields a functional TRA-protein that forms a complex with TRA2, encoded by a transformer-2 (tra2) ortholog, to act as a sex specific splicing regulator of the downstream transcription factors doublesex (dsx) and fruitless (fru). Here, we identify the tra2 ortholog of the haplodiploid parasitoid wasp N. vitripennis (Nv-tra2) and confirm its function in N. vitripennis sex determination. Knock down of Nv-tra2 by parental RNA interference (pRNAi) results in complete sex reversal of diploid offspring from female to male, indicating the requirement of Nv-tra2 for female sex determination. As Nv-tra2 pRNAi leads to frequent lethality in early developmental stages, maternal provision of Nv-tra2 transcripts is apparently also required for another, non-sex determining function during embryogenesis. In addition, lethality following Nv-tra2 pRNAi appears more pronounced in diploid than in haploid offspring. This diploid lethal effect was also observed following Nv-tra pRNAi, which served as a positive control in our experiments. As diploid embryos from fertilized eggs have a paternal chromosome set in addition to the maternal one, this suggests that either the presence of this paternal chromosome set or the dosage effect resulting from the diploid state is incompatible with the induced male development in N. vitripennis caused by either Nv-tra2 or Nv-tra pRNAi. The role of Nv-tra2 in activating the female sex determination pathway yields more insight into the sex determination mechanism of Nasonia.
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      PubDate: 2017-09-20T02:58:32Z
      DOI: 10.1016/j.ibmb.2017.09.007
       
  • Adipokinetic hormone receptor gene identification and its role in
           triacylglycerol mobilization and sexual behavior in the oriental fruit fly
           (Bactrocera dorsalis)
    • Authors: Qiu-Li Hou; Er-Hu Chen; Hong-Bo Jiang; Dan-Dan Wei; Shun-Hua Gui; Jin-Jun Wang; Guy Smagghe
      Abstract: Publication date: Available online 15 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Qiu-Li Hou, Er-Hu Chen, Hong-Bo Jiang, Dan-Dan Wei, Shun-Hua Gui, Jin-Jun Wang, Guy Smagghe
      Energy homeostasis requires continuous compensation for fluctuations in energy expenditure and availability of food resources. In insects, energy mobilization is under control of the adipokinetic hormone (AKH) where it is regulating the nutritional status by supporting the mobilization of lipids. In this study, we characterized the gene coding for the AKH receptor (AKHR) and investigated its function in the oriental fruit fly (Bactrocera dorsalis) that is economically one of the most important pest insects of tropical and subtropical fruit. Bacdo-AKHR is a typical G protein-coupled receptor (GPCR) and phylogenetic analysis confirmed that Bacdo-AKHR is closely related to insect AKHRs from other species. When expressed in Chinese hamster ovary (CHO) cells, Bacdo-AKHR exhibited a high sensitivity and selectivity for AKH peptide (EC50 = 19.3 nM). Using qPCR, the developmental stage and tissue-specific expression profiles demonstrated that Bacdo-AKHR was highly expressed in both the larval and adult stages, and also specifically in the fat body and midgut of the adult with no difference in sex. To investigate the role of AKHR in B. dorsalis, RNAi assays were performed with dsRNA against Bacdo-AKHR in adult flies of both sexes and under starvation and feeding condition. As major results, the knockdown of this gene resulted in triacylglycerol (TAG) accumulation. With RNAi-males, we observed a severe decrease in their sexual courtship activity when starved, but there was a partial rescue in copulation when refed. Also in RNAi-males, the tethered-flight duration declined compared with the control group when starved, which is confirming the dependency on energy metabolism. In RNAi-females, the sexual behavior was not affected, but their fecundity was decreased. Our findings indicate an interesting role of AKHR in the sexual behavior of males specifically. The effects are associated with TAG accumulation, and we also reported that the conserved role of AKH-mediated system in B. dorsalis is nutritional state-dependent. Hence, we provided further understanding on the multiple functions of AKH/AKHR in B. dorsalis.
      Graphical abstract image

      PubDate: 2017-09-20T02:58:32Z
      DOI: 10.1016/j.ibmb.2017.09.006
       
  • Recombinant expression and characterization of Lucilia cuprina CYP6G3:
           Activity and binding properties toward multiple pesticides
    • Authors: Matthew J. Traylor; Jong-Min Baek; Katelyn E. Richards; Roberto Fusetto; W. Huang; Peter Josh; Zhengzhong Chen; Padma Bollapragada; Richard A.J. O'Hair; Philip Batterham; Elizabeth M.J. Gillam
      Abstract: Publication date: Available online 14 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Matthew J. Traylor, Jong-Min Baek, Katelyn E. Richards, Roberto Fusetto, W. Huang, Peter Josh, Zhengzhong Chen, Padma Bollapragada, Richard A.J. O'Hair, Philip Batterham, Elizabeth M.J. Gillam
      The Australian sheep blowfly, Lucilia cuprina, is a primary cause of sheep flystrike and a major agricultural pest. Cytochrome P450 enzymes have been implicated in the resistance of L. cuprina to several classes of insecticides. In particular, CYP6G3 is a L. cuprina homologue of Drosophila melanogaster CYP6G1, a P450 known to confer multi-pesticide resistance. To investigate the basis of resistance, a bicistronic Escherichia coli expression system was developed to co-express active L. cuprina CYP6G3 and house fly (Musca domestica) P450 reductase. Recombinant CYP6G3 showed activity towards the high-throughput screening substrates, 7-ethoxycoumarin and p-nitroanisole, but not towards p-nitrophenol, coumarin, 7-benzyloxyresorufin, or seven different luciferin derivatives (P450-Glo™ substrates). The addition of house fly cytochrome b 5 enhanced the kcat for p-nitroanisole dealkylation approximately two fold (17.8 ± 0.5 vs 9.6 ± 0.2 min−1) with little effect on KM (13 ± 1 vs 10 ± 1 μM). Inhibition studies and difference spectroscopy revealed that the organochlorine compounds, DDT and endosulfan, and the organophosphate pesticides, malathion and chlorfenvinphos, bind to the active site of CYP6G3. All four pesticides showed type I binding spectra with spectral dissociation constants in the micromolar range suggesting that they may be substrates of CYP6G3. While no significant inhibition was seen with the organophosphate, diazinon, or the neonicotinoid, imidacloprid, diazinon showed weak binding in spectral assays, with a Kd value of 23 ± 3 μM CYP6G3 metabolised diazinon to the diazoxon and hydroxydiazinon metabolites and imidacloprid to the 5-hydroxy and olefin metabolites, consistent with a proposed role of CYP6G enzymes in metabolism of phosphorothioate and neonicotinoid insecticides in other species.
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      PubDate: 2017-09-14T11:48:29Z
      DOI: 10.1016/j.ibmb.2017.09.004
       
  • Identification of circular RNA in the Bombyx mori silk gland
    • Authors: Huaiyan Gan; Tieshan Feng; Yuqian Wu; Chun Liu; Qingyou Xia; Tingcai Cheng
      Abstract: Publication date: Available online 14 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Huaiyan Gan, Tieshan Feng, Yuqian Wu, Chun Liu, Qingyou Xia, Tingcai Cheng
      Bombyx mori is an economically important holometabolous lepidopteran insect. In B. mori endogenous noncoding RNAs such as microRNAs (miRNAs) and Piwi-interacting RNAs play crucial biological functions in metamorphosis and sex determination. In addition, circular RNAs (circRNAs) have been recently identified as noncoding RNAs in most common model organisms and show potential as gene regulators. However, to date, there have been few studies on the circRNAs present in the B. mori genome conducted to date. Here, we identified 3916 circRNAs by deep circular transcriptome sequencing using the silk gland of B. mori. 3155 circRNAs were found to be derived from 1727 parental genes. The circRNAs displayed tissue-specific expression between the middle silk gland (MSG) and posterior silk gland (PSG), with 2532 and 880 being upregulated circRNAs in the MSG and PSG, respectively. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses showed that the parental genes from the MSG and PSG were generally annotated to similar categories and pathways. The interaction network of circRNAs and miRNAs showed that circRNAs might act as miRNA sponges or interact with miRNAs in some other way. Overall, the results revealed the complicated patterns of circRNAs in the B. mori silk gland providing a new angle from which to explore the mechanisms of complex gene regulation and efficient silk protein synthesis.
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      PubDate: 2017-09-14T11:48:29Z
      DOI: 10.1016/j.ibmb.2017.09.003
       
  • CRISPR/Cas9 mediated G4946E substitution in the ryanodine receptor of
           Spodoptera exigua confers high levels of resistance to diamide
           insecticides
    • Authors: Yayun Zuo; Hui Wang; Yanjun Xu; Jianlei Huang; Shuwen Wu; Yidong Wu; Yihua Yang
      Abstract: Publication date: Available online 12 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yayun Zuo, Hui Wang, Yanjun Xu, Jianlei Huang, Shuwen Wu, Yidong Wu, Yihua Yang
      Diamide insecticides selectively activate insect ryanodine receptors (RyRs), inducing uncontrolled release of calcium ions, and causing muscle contraction, paralysis and eventually death. The RyRG4946E substitution associated with diamide resistance has been identified in three lepidopteran pests, Plutella xylostella, Tuta absoluta and Chilo suppressalis. Recently, the T. absoluta RyRG4946V mutation was knocked into the model insect Drosophila melanogaster by CRISPR/Cas9 mediated genome editing and provided in vivo functional confirmation for its role in diamide resistance. In the present study, we successfully introduced the RyRG4946E mutation with CRISPR/Cas9 technology into a lepidopteran pest of global importance, Spodoptera exigua. The genome-edited strain (named 4946E) homozygous for the SeRyRG4946E mutation exhibited 223-, 336- and >1000-fold resistance to chlorantraniliprole, cyantraniliprole and flubendiamide, respectively when compared to the wild type strain (WHS) of S. exigua. Reciprocal crossing experiments revealed that the target-site resistance in strain 4946E underlies an autosomal and almost recessive mode of inheritance for anthranilic diamides, whereas it was completely recessive for flubendiamide. Our results not only provided in vivo functional validation of the RyRG4946E mutation in conferring high levels of resistance to diamide insecticides for the first time in a controlled genetic background of a lepidopteran pest, but also revealed slight differences on the level of resistance between anthranilic diamides (chlorantraniliprole and cyantraniliprole) and flubendiamide conferred by the SeRyRG4946E mutation.
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      PubDate: 2017-09-14T11:48:29Z
      DOI: 10.1016/j.ibmb.2017.09.005
       
  • Molecular basis of peripheral olfactory sensing during oviposition in the
           behavior of the parasitic wasp Anastatus japonicus
    • Authors: Yinliang Wang; Qi Chen; Junqi Guo; Jing Li; Jiatong Wang; Ming Wen; Hanbo Zhao; Bingzhong Ren
      Abstract: Publication date: Available online 11 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yinliang Wang, Qi Chen, Junqi Guo, Jing Li, Jiatong Wang, Ming Wen, Hanbo Zhao, Bingzhong Ren
      Anastatus japonicus is a parasitic wasp and natural enemy of the litchi pest Tessaratoma papillosa, and for decades in China, A. japonicus has been mass-reared inside the eggs of Antheraea pernyi to control T. papillosa. A series of experiments was performed to explore the olfactory mechanism underlying the oviposition behavior of A. japonicus. First, a transcriptomic analysis was performed on the antennae of A. japonicus, and the resulting assemblies led to the generation of 70,473 unigenes. Subsequently, 21,368 unigenes were matched to known proteins, and 48 odorant receptors (ORs) (including Orco) and 13 antennal ionotropic receptors (IRs) (including the co-receptors IR8a and IR25a) were identified and predicted to form complete open reading frames (ORFs). The FPKM (fragments per Kb per million reads) values and RT-PCR results showed that AjapOrco, AjapOR10, AjapOR11, AjapOR27, AjapOR29, AjapOR33, AjapOR34 and AjapOR35 were either highly abundant or expressed specifically in the olfactory organs. Furthermore, AjapOrco silencing resulted in a significant decrease in both the parasitism rate and the host-seeking time of A. japonicus, whereas dsRNA injection showed that IR8a and IR25a did not produce significant behavioral changes, suggesting that the oviposition behavior of A. japonicus is more reliant on OR-based pathways than IR-based pathways. Our previous GC-MS data derived twenty-nine compounds from these host plants and host insects. We performed electrophysiological and oviposition assays on A. japonicus, and eight odorants were found to elicit a significant electroantennogram (EAG) response. Among these odorants, β-Caryophyllene, Undecane, (E)-α-Farnesene (+)-Aromadendrene and Cis-3-Hexen-ol had strong attractant effects on oviposition, whereas 2-Ethyl-1-Hexan-ol, Ethyl Acetate and α-Caryophyllene had a strong repellant effects. Thus, these chemicals might influence oviposition guidance/repulsion behavior in A. japonicus. To further explore the target ORs that are tuned to the functional odorants, the nine candidate ORs described above were silenced by RNA interference, and the results showed that a large decrease in the EAG response of all the tested functional odorants in the AjapOrco-silencing group. In addition, the AjapOR35-silencing group showed a significant decrease in the EAG response to β-Caryophyllene and (E)-α-Farnesene, indicating that AjapOR35 is tuned to these two oviposition attractants β-Caryophyllene and (E)-α-Farnesene. Further binary-choice oviposition assays showed that the oviposition attractant effect of β-Caryophyllene and (E)-α-Farnesene vanished after AjapOR35 was silenced, indicating that the emission of these attractants from host plants can guide A. japonicus to locate eggs for ovipositioning and indicated that AjapOR35 is correlated with the olfactory detection oviposition behavior of this species. This study provides a better understanding of the molecular basis and functional chemicals underlying the oviposition behavior of A. japonicus, and the results may help improve biocontrol approaches.
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      PubDate: 2017-09-14T11:48:29Z
      DOI: 10.1016/j.ibmb.2017.09.001
       
  • Functional characterization of Pol III U6 promoters for gene knockdown and
           knockout in Plutella xylostella
    • Authors: Yuping Huang; Yajun Wang; Baosheng Zeng; Zhaoxia Liu; Xuejiao Xu; Qian Meng; Yongping Huang; Guang Yang; Liette Vasseur; Geoff M. Gurr; Minsheng You
      Abstract: Publication date: Available online 7 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yuping Huang, Yajun Wang, Baosheng Zeng, Zhaoxia Liu, Xuejiao Xu, Qian Meng, Yongping Huang, Guang Yang, Liette Vasseur, Geoff M. Gurr, Minsheng You
      RNA polymerase type III (Pol-III) promoters such as U6 are commonly used to express small RNAs, including short hairpin RNAs (shRNAs) and single guide RNAs (sgRNAs). Functional U6 promoters are widely used in CRISPR systems, and their characterization can facilitate genome editing of non-model organisms. In the present study, six U6 small nuclear RNA (snRNA) promoters containing two conserved elements of a proximal sequence element (PSEA) and a TATA box, were identified and characterized in the diamondback moth (Plutella xylostella) genome. Relative efficiency of the U6 promoters to express shRNA induced EGFP knockdown was tested in a P. xylostella cell line, revealing that the PxU6:3 promoter had the strongest expression effect. Further work with the PxU6:3 promoter showed its efficacy in EGFP knockout using CRISPR/Cas9 system in the cells. The expression plasmids with versatile Pxabd-A gene specific sgRNA driven by the PxU6:3 promoter, combined with Cas9 mRNA, could induce mutagenesis at specific genomic loci in vivo. The phenotypes induced by sgRNA expression plasmids were similar to those done in vitro transcription sgRNAs. A plasmid with two tandem arranged PxU6:3:sgRNA expression cassettes targeting Pxabd-A loci was generated, which caused a 28,856 bp fragment deletion, suggesting that the multi-sgRNA expression plasmid can be used for multi-targeting. Our work indicates that U6 snRNA promoters can be used for functional studies of genes with the approach of reverse genetics in P. xylostella. These essential promoters also provide valuable potential for CRISPR-derived gene drive as a tactic for population control in this globally significant pest.
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      PubDate: 2017-09-09T14:15:59Z
      DOI: 10.1016/j.ibmb.2017.08.009
       
  • Osiris9a is a major component of silk fiber in lepidopteran insects
    • Authors: Chun Liu; Wenbo Hu; Tingcai Cheng; Zhangchuan Peng; Kazuei Mita; Qingyou Xia
      Abstract: Publication date: Available online 5 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Chun Liu, Wenbo Hu, Tingcai Cheng, Zhangchuan Peng, Kazuei Mita, Qingyou Xia
      In a previous high-throughput proteomics study, it was found that the silkworm cocoon contains hundreds of complex proteins, many of which have unknown functions, in addition to fibroins, sericins, and some protease inhibitors. Osiris was one of the proteins with no known function. In this study, we identified the Osiris gene family members and constructed a phylogenetic tree based on the sequences from different species. Our results indicate that the Osiris9 gene subfamily contains six members; it is specifically expressed in lepidopteran insects and has evolved by gene duplication. An Osiris gene family member from Bombyx mori was designated as BmOsiris9a (BmOsi9a) on the basis of its homology to Drosophila melanogaster Osiris9. The expression pattern of BmOsi9a showed that it was highly expressed only in the middle silk gland of silkworm larvae, similar to Sericin1 (Ser1). BmOsi9a was visualized as two bands in western blot analysis, implying that it probably undergoes post-translational modifications. Immunohistochemistry analysis revealed that BmOsi9a was synthesized and secreted into the lumen of the middle silk gland, and was localized in the sericin layer in the silk fiber. BmOsi9a was found in the silk fibers of not only three Bombycidae species, viz. B. mori, B. mandarina, and B. huttoni, but also in the fibers collected from Saturniidae species, including Antheraea assama, Antheraea mylitta, and Samia cynthia. Although the exact biological function of Osi9a in the silk fibers is unknown, our results are important because they demonstrate that Osi9a is a common structural component of silk fiber and is expressed widely among the silk-producing Bombycidae and Saturniidae insects. Our results should help in understanding the role of Osi9a in silk fibers.
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      PubDate: 2017-09-09T14:15:59Z
      DOI: 10.1016/j.ibmb.2017.09.002
       
  • Lipidation of BmAtg8 is required for autophagic degradation of p62 bodies
           containing ubiquitinated proteins in the silkworm, Bombyx mori
    • Authors: Ming-Ming Ji; Jae Man Lee; Hiroaki Mon; Kazuhiro Iiyama; Tsuneyuki Tatsuke; Daisuke Morokuma; Masato Hino; Mami Yamashita; Kazuma Hirata; Takahiro Kusakabe
      Abstract: Publication date: Available online 1 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Ming-Ming Ji, Jae Man Lee, Hiroaki Mon, Kazuhiro Iiyama, Tsuneyuki Tatsuke, Daisuke Morokuma, Masato Hino, Mami Yamashita, Kazuma Hirata, Takahiro Kusakabe
      p62/Sequestosome-1 (p62/SQSTM1, hereafter referred to as p62) is a major adaptor that allows ubiquitinated proteins to be degraded by autophagy, and Atg8 homologs are required for p62-mediated autophagic degradation, but their relationship is still not understood in Lepidopteran insects. Here it is clearly demonstrated that the silkworm homolog of mammalian p62, Bombyx mori p62 (Bmp62), forms p62 bodies depending on its Phox and Bem1p (PB1) and ubiquitin-associated (UBA) domains. These two domains are associated with Bmp62 binding to ubiquitinated proteins to form the p62 bodies, and the UBA domain is essential for the binding, but Bmp62 still self-associates without the PB1 or UBA domain. The p62 bodies in Bombyx cells are enclosed by BmAtg9-containing membranes and degraded via autophagy. It is revealed that the interaction between the Bmp62 AIM motif and BmAtg8 is critical for the autophagic degradation of the p62 bodies. Intriguingly, we further demonstrate that lipidation of BmAtg8 is required for the Bmp62-mediated complete degradation of p62 bodies by autophagy. Our results should be useful in future studies of the autophagic mechanism in Lepidopteran insects.
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      PubDate: 2017-09-03T19:53:40Z
      DOI: 10.1016/j.ibmb.2017.08.006
       
  • Gene expression and molecular characterization of a novel C-type lectin,
           encapsulation promoting lectin (EPL), in the rice armyworm, Mythimna
           separata
    • Authors: Teruhito Ishihara; Yuki Maruyama; Seiichi Furukawa
      Abstract: Publication date: Available online 1 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Teruhito Ishihara, Yuki Maruyama, Seiichi Furukawa
      Insect cellular immune reactions differ depending on the target species. Phagocytosis is activated to scavenge microorganisms such as bacteria and fungi. On the other hand, larger invaders such as parasitoid wasps are eliminated by activation of encapsulation. In this study, we hypothesized that novel determinants regulate cellular immunities independent of surface molecular pattern recognition involving pattern recognition receptors (PRRs). Immune-related genes differentially expressed depending on the treated material size were screened in larval hemocytes of the rice armyworm, Mythimna separata. Consequently, we identified a novel C-type lectin gene up-regulated by injection of large beads but not small beads of identical material. Examination of in vitro effect of the recombinant protein on the immune reactions clarified that the protein activated encapsulation reaction, while it suppressed phagocytosis. These results suggest that this novel C-type lectin designated “encapsulation promoting lectin (EPL)” regulates cellular immunity by a novel immune target size-recognition mechanism.
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      PubDate: 2017-09-03T19:53:40Z
      DOI: 10.1016/j.ibmb.2017.08.008
       
  • Substitutions in the cardenolide binding site and interaction of subunits
           affect kinetics besides cardenolide sensitivity of insect Na,K-ATPase
    • Authors: Safaa Dalla; Michael Baum; Susanne Dobler
      Abstract: Publication date: Available online 1 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Safaa Dalla, Michael Baum, Susanne Dobler
      Substitutions within the cardenolide target site of several insects' Na,K-ATPase α-subunits may confer resistance against toxic cardenolides. However, to which extent these substitutions alter the Na,K-ATPase's kinetic properties and how they interact with different β-subunits is not clear. The cardenolide-adapted milkweed bug Oncopeltus fasciatus possesses three paralogs of the α-subunit (A, B, and C) that differ in number and identity of resistance-conferring substitutions. We introduced these substitutions into the α-subunit of Drosophila melanogaster and combined them with the β-subunits Nrv2.2 and Nrv3. The substitutions Q111T-N122H-F786N-T797A (A-copy mimic) and Q111T-N122H-F786N (B-copy mimic) mediated high insensitivity to ouabain, yet they drastically lowered ATPase activity. Remarkably, the identity of the β-subunit was decisive and all α-subunits were less active when combined with Nrv3 than when combined with Nrv2.2. Both the substitutions and the co-expressed β-subunit strongly affected the enyzme's affinity for Na+ and K+. Na+ affinity was considerably higher for all enzymes expressed with nrv3 while expression with nrv2.2 increased K+ affinity. Our results provide the first evidence that resistance against cardenolides comes at the cost of significantly altered kinetic properties of the Na,K-ATPase. The β-subunit can strongly modulate these properties but cannot fully compensate for the effect of the substitutions.
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      PubDate: 2017-09-03T19:53:40Z
      DOI: 10.1016/j.ibmb.2017.08.005
       
  • Mdr65 decreases toxicity of multiple insecticides in Drosophila
           melanogaster
    • Authors: Haina Sun; Nicolas Buchon; Jeffrey G. Scott
      Abstract: Publication date: Available online 10 August 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Haina Sun, Nicolas Buchon, Jeffrey G. Scott
      ABC transporters are ubiquitous membrane-bound proteins, present in both prokaryotes and eukaryotes. The major function of eukaryotic ABC transporters is to mediate the efflux of a variety of substrates (including xenobiotics) out of cells. ABC transporters have been widely investigated in humans, particularly for their involvement in multidrug resistance (MDR). Considerably less is known about their roles in transport and/or excretion in insects. ABC transporters are only known to function as exporters in insects. Drosophila melanogaster has 56 ABC transporter genes, including eight which are phylogenetically most similar to the human Mdr genes (ABCB1 clade). We investigated the role of ABC transporters in the ABCB1 clade in modulating the susceptibility to insecticides. We took advantage of the GAL4/UAS system in D. melanogaster to knockdown the expression levels of Mdr65, Mdr50, Mdr49 and ABCB6 using transgenic UAS-RNAi lines and conditional driver lines. The most notable effects were increased sensitivities to nine different insecticides by silencing of Mdr65. Furthermore, a null mutation of Mdr65 decreased the malathion, malaoxon and fipronil LC50 values by a factor of 1.9, 2.1 and 3.9, respectively. Altogether, this data demonstrates the critical role of ABC transporters, particularly Mdr65, in altering the toxicity of specific, structurally diverse, insecticides in D. melanogaster.
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      PubDate: 2017-08-14T15:46:16Z
      DOI: 10.1016/j.ibmb.2017.08.002
       
  • Identification of Cry48Aa/Cry49Aa toxin ligands in the midgut of Culex
           quinquefasciatus larvae
    • Authors: Tatiana Maria Teodoro Rezende; Tatiany Patrícia Romão; Michel Batista; Colin Berry; Michael J. Adang; Maria Helena Neves Lobo Silva-Filha
      Abstract: Publication date: Available online 3 August 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Tatiana Maria Teodoro Rezende, Tatiany Patrícia Romão, Michel Batista, Colin Berry, Michael J. Adang, Maria Helena Neves Lobo Silva-Filha
      A binary mosquitocidal toxin composed of a three-domain Cry-like toxin (Cry48Aa) and a binary-like toxin (Cry49Aa) was identified in Lysinibacillus sphaericus. Cry48Aa/Cry49Aa has action on Culex quinquefasciatus larvae, in particular, to those that are resistant to the Bin Binary toxin, which is the major insecticidal factor from L. sphaericus-based biolarvicides, indicating that Cry48Aa/Cry49Aa interacts with distinct target sites in the midgut and can overcome Bin toxin resistance. This study aimed to identify Cry48Aa/Cry49Aa ligands in C. quinquefasciatus midgut through binding assays and mass spectrometry. Several proteins, mostly from 50 to 120 kDa, bound to the Cry48Aa/Cry49Aa toxin were revealed by toxin overlay and pull-down assays. These proteins were identified against the C. quinquefasciatus genome and after analysis a set of 49 proteins were selected which includes midgut bound proteins such as aminopeptidases, amylases, alkaline phosphatases in addition to molecules from other classes that can be potentially involved in this toxin's mode of action. Among these, some proteins are orthologs of Cry receptors previously identified in mosquito larvae, as candidate receptors for Cry48Aa/Cry49Aa toxin. Further investigation is needed to evaluate the specificity of their interactions and their possible role as receptors.
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      PubDate: 2017-08-04T14:31:28Z
      DOI: 10.1016/j.ibmb.2017.08.001
       
  • Serine protease-related proteins in the malaria mosquito, Anopheles
           gambiae
    • Authors: Xiaolong Cao; Mansi Gulati; Haobo Jiang
      Abstract: Publication date: Available online 2 August 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Xiaolong Cao, Mansi Gulati, Haobo Jiang
      Insect serine proteases (SPs) and serine protease homologs (SPHs) participate in digestion, defense, development, and other physiological processes. In mosquitoes, some clip-domain SPs and SPHs (i.e. CLIPs) have been investigated for possible roles in antiparasitic responses. In a recent test aimed at improving quality of gene models in the Anopheles gambiae genome using RNA-seq data, we observed various discrepancies between gene models in AgamP4.5 and corresponding sequences selected from those modeled by Cufflinks, Trinity and Bridger. Here we report a comparative analysis of the 337 SP-related proteins in A. gambiae by examining their domain structures, sequence diversity, chromosomal locations, and expression patterns. One hundred and ten CLIPs contain 1 to 5 clip domains in addition to their protease domains (PDs) or non-catalytic, protease-like domains (PLDs). They are divided into five subgroups: CLIPAs (22) are clip1−5-PLD; CLIPBs (29), CLIPCs (12) and CLIPDs (14) are mainly clip-PD; most CLIPEs (33) have a domain structure of PD/PLD-PLD-clip-PLD0−1. While expression of the CLIP genes in group-1 is generally low and detected in various tissue- and stage-specific RNA-seq libraries, some putative GPs/GPHs (i.e. single domain gut SPs/SPHs) in group-2 are highly expressed in midgut, whole larva or whole adult libraries. In comparison, 46 SPs, 26 SPHs, and 37 multi-domain SPs/SPHs (i.e. PD/PLD-PLD≥1) in group-3 do not seem to be specifically expressed in digestive tract. There are 16 SPs and 2 SPH containing other types of putative regulatory domains (e.g. LDLa, CUB, Gd). Of the 337 SP and SPH genes, 159 were sorted into 46 groups (2–8 members/group) based on similar phylogenetic tree position, chromosomal location, and expression profile. This information and analysis, including improved gene models and protein sequences, constitute a solid foundation for functional analysis of the SP-related proteins in A. gambiae.
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      PubDate: 2017-08-04T14:31:28Z
      DOI: 10.1016/j.ibmb.2017.07.008
       
  • Gustatory receptor 22e is essential for sensing chloroquine and strychnine
           in Drosophila melanogaster
    • Authors: Seeta Poudel; Yunjung Kim; Junseok Kwak; Sangyun Jeong; Youngseok Lee
      Abstract: Publication date: Available online 24 July 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Seeta Poudel, Yunjung Kim, Junseok Kwak, Sangyun Jeong, Youngseok Lee
      Chloroquine, an amino quinolone derivative commonly used as an anti-malarial drug, is known to impart an unpleasant taste. Little research has been done to study chloroquine taste in insects, therefore, we examined both the deterrant properties and mechanisms underlying chloroquine perception in fruit flies. We identified the antifeedant effect of chloroquine by screening 21 gustatory receptor (Grs) mutants through behavioral feeding assays and electrophysiology experiments. We discovered that two molecular sensors, GR22e and GR33a, act as chloroquine receptors, and found that chloroquine-mediated activation of GRNs occurs through S-type sensilla. At the same time, we successfully recapitulated the chloroquine receptor by expressing GR22e in ectopic gustatory receptor neurons. We also found that GR22e forms a part of the strychnine receptor. We suggest that the Drosophila strychnine receptor might have a very complex structure since five different GRs are required for strychnine-induced action potentials.
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      PubDate: 2017-07-26T13:33:28Z
      DOI: 10.1016/j.ibmb.2017.07.007
       
  • Towards an understanding of the molecular basis of effective RNAi against
           a global insect pest, the whitefly Bemisia tabaci
    • Authors: Yuan Luo; Qingguo Chen; Junbo Luan; Seung Ho Chung; Joyce Van Eck; R. Turgeon; Angela E. Douglas
      Abstract: Publication date: Available online 21 July 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yuan Luo, Qingguo Chen, Junbo Luan, Seung Ho Chung, Joyce Van Eck, R. Turgeon, Angela E. Douglas
      In planta RNAi against essential insect genes offers a promising route to control insect crop pests, but is constrained for many insect groups, notably phloem sap-feeding hemipterans, by poor RNAi efficacy. This study conducted on the phloem-feeding whitefly Bemisia tabaci reared on tomato plants investigated the causes of low RNAi efficacy and routes to ameliorate the problem. Experiments using tomato transgenic lines containing ds-GFP (green fluorescent protein) revealed that full-length dsRNA is phloem-mobile, ingested by the insects, and degraded in the insect. We identified B. tabaci homologs of nuclease genes (dsRNases) in other insects that degrade dsRNA, and demonstrated that degradation of ds-GFP in B. tabaci is suppressed by administration of dsRNA against these genes. dsRNA against the nuclease genes was co-administered with dsRNA against two insect genes, an aquaporin AQP1 and sucrase SUC1, that are predicted to protect B. tabaci against osmotic collapse. When dsRNA constructs for AQP1, SUC1, dsRNase1 and dsRNase2 were stacked, insect mortality was significantly elevated to 50% over 6 days on artificial diets. This effect was accompanied by significant reduction in gene expression of the target genes in surviving diet-fed insects. This study offers proof-of-principle that the efficacy of RNAi against insect pests can be enhanced by using dsRNA to suppress the activity of RNAi-suppressing nuclease genes, especially where multiple genes with related physiological function but different molecular function are targeted.
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      PubDate: 2017-07-26T13:33:28Z
      DOI: 10.1016/j.ibmb.2017.07.005
       
  • Amblyomma maculatum SECIS binding protein 2 and putative selenoprotein P
           are indispensable for pathogen replication and tick fecundity
    • Authors: Khemraj Budachetri; Gary Crispell; Shahid Karim
      Abstract: Publication date: Available online 21 July 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Khemraj Budachetri, Gary Crispell, Shahid Karim
      Selenium, a vital trace element, is incorporated into selenoproteins to produce selenocysteine. Our previous studies have revealed an adaptive co-evolutionary process that has enabled the spotted fever-causing tick-borne pathogen Rickettsia parkeri to survive by manipulating an antioxidant defense system associated with selenium, which includes a full set of selenoproteins and other antioxidants in ticks. Here, we conducted a systemic investigation of SECIS binding protein 2 (SBP2) and putative selenoprotein P (SELENOP) by transcript silencing in adult female Gulf-coast ticks (Amblyomma maculatum). Knockdown of the SBP2 and SELENOP genes depleted the respective transcript levels of these tick selenogenes, and caused differential regulation of other antioxidants. Importantly, the selenium level in the immature and mature tick stages increased significantly after a blood meal, but the selenium level decreased in ticks after the SBP2 and SELENOP knockdowns. Moreover, the SBP2 knockdown significantly impaired both transovarial transmission of R. parkeri to tick eggs and egg hatching. Overall, our data offer new insight into the relationship between the SBP2 selenoprotein synthesis gene and the putative tick SELENOP gene. It also augments our understanding of selenoprotein synthesis, selenium maintenance and utilization, and bacterial colonization of a tick vector.
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      PubDate: 2017-07-26T13:33:28Z
      DOI: 10.1016/j.ibmb.2017.07.006
       
  • Gene expression changes in honey bees induced by sublethal imidacloprid
           exposure during the larval stage
    • Authors: Ming-Cheng Wu; Yu-Wen Chang; Kuang-Hui Lu; En-Cheng Yang
      Abstract: Publication date: Available online 18 July 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Ming-Cheng Wu, Yu-Wen Chang, Kuang-Hui Lu, En-Cheng Yang
      Honey bee larvae exposed to sublethal doses of imidacloprid show behavioural abnormalities as adult insects. Previous studies have demonstrated that this phenomenon originates from abnormal neural development in response to imidacloprid exposure. Here, we further investigated the global gene expression changes in the heads of newly emerged adults and observed that 578 genes showed more than 2-fold changes in gene expression after imidacloprid exposure. This information might aid in understanding the effects of pesticides on the health of pollinators. For example, the genes encoding major royal jelly proteins (MRJPs), a group of multifunctional proteins with significant roles in the sustainable development of bee colonies, were strongly downregulated. These downregulation patterns were further confirmed through analyses using quantitative reverse transcription-polymerase chain reaction on the heads of 6-day-old nurse bees. To our knowledge, this study is the first to demonstrate that sublethal doses of imidacloprid affect mrjp expression and likely weaken bee colonies.
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      PubDate: 2017-07-20T02:25:55Z
      DOI: 10.1016/j.ibmb.2017.06.016
       
  • BmCHSA-2b, a Lepidoptera specific alternative splicing variant of
           epidermal chitin synthase, is required for pupal wing development in
           Bombyx mori
    • Authors: Guangfeng Xu; Jie Zhang; Jia Liu; Yang Ding; Qili Feng; Qisheng Song; Sichun Zheng
      Abstract: Publication date: Available online 1 July 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Guangfeng Xu, Jie Zhang, Jia Liu, Yang Ding, Qili Feng, Qisheng Song, Sichun Zheng
      Insect chitin synthase A (CHSA) is an epidermis-specific enzyme that plays an essential role in insect development. In this study, the function and regulation of CHSA-2b, an alternative splicing variant of Bombxy mori CHSA that is discovered only in Lepidopteran insects, were investigated. Analysis of mRNA level showed that BmCHSA-2b was responsive to 20-hydroxyecdysone (20E) in pupal wing unlike BmCHSA-2a, which shares almost the identical sequence as BmCHSA-2b except the first 31 amino acids, suggesting that the expression of these two alternative splicing variants is driven by different promoters of CHSA gene. Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) analysis showed that BmCHSA-2b was up-regulated in the wing of mid-pupa unlike BmCHSA-2a, which was up-regulated in epidermis and wing disc at the beginning and end of pupal stage. Further analysis reveals that the up-regulations of BmCHSA-2a and BmCHSA-2b in pupal wing were consistent with the increase of chitin content and wing area at the same stages, respectively. Furthermore, the higher transcription level of BmCHSA-2b in the mid-pupal wing of male than that in female was consistent with the chitin content of pupal wing between genders. Injection of double-stranded RNAs of BmCHSA-2b resulted in the decrease in the area and chitin content of the wing, and irregular and crimpled vein. All these results together suggest that B. mori evolves an extra promoter in CHSA gene to activate BmCHSA-2b expression in the wing of mid-pupal stage in response to 20E, and BmCHSA-2b is required for the wing development in the mid-pupa of B. mori.
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      PubDate: 2017-07-10T07:34:33Z
      DOI: 10.1016/j.ibmb.2017.06.017
       
  • Investigation of the contribution of RyR target-site mutations in diamide
           resistance by CRISPR/Cas9 genome modification in Drosophila
    • Authors: Vassilis Douris; Kyriaki-Maria Papapostolou; Aris Ilias; Emmanuel Roditakis; Styliani Kounadi; Maria Riga; Ralf Nauen; John Vontas
      Abstract: Publication date: Available online 29 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Vassilis Douris, Kyriaki-Maria Papapostolou, Aris Ilias, Emmanuel Roditakis, Styliani Kounadi, Maria Riga, Ralf Nauen, John Vontas
      Diamide insecticides are used widely against lepidopteran pests, acting as potent activators of insect Ryanodine Receptors (RyRs) and thus inducing muscle contraction and eventually death. However, resistant phenotypes have recently evolved in the field, associated with the emergence of target site resistance mutations (G4946E/V and I4790M). We investigated the frequency of the mutations found in a resistant population of Tuta absoluta from Greece (G4946V–79% and I4790M–21%) and the associated diamide resistance profile: there are very high levels of resistance against chlorantraniliprole (9329-fold) and flubendiamide (4969-fold), but moderate levels against cyantraniliprole (191-fold). To further investigate functionally the contribution of each mutation in the resistant phenotype, we used CRISPR/Cas9 to generate genome modified Drosophila carrying alternative allele combinations, and performed toxicity bioassays against all three marketed diamides. Genome modified flies bearing the G4946V mutation exhibited high resistance to flubendiamide (91.3-fold) and chlorantraniliprole (194.7-fold), but low in cyantraniliprole (5.4-fold). Flies naturally bearing the I4790M mutation were moderately resistant to flubendiamide (15.3-fold) but less resistant to chlorantraniliprole (7.5-fold), and cyantraniliprole (2.3-fold). These findings provide in vivo functional genetic confirmation for the role and relative contribution of RyR mutations in diamide resistance and suggest that the three diamides employ different binding modes on the RyR protein.
      Graphical abstract image

      PubDate: 2017-07-01T03:03:53Z
      DOI: 10.1016/j.ibmb.2017.06.013
       
  • Voltage-sensitive potassium channels expressed after 20-Hydroxyecdysone
           treatment of a mosquito cell line
    • Authors: Lacey J. Jenson; Baonan Sun; Jeffrey R. Bloomquist
      Abstract: Publication date: Available online 28 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Lacey J. Jenson, Baonan Sun, Jeffrey R. Bloomquist
      The goal of this research was to express receptors and ion channels in hormone-treated insect cell lines. Treatment of Anopheles gambiae Sua1B cells with 20-hydroxyecdysone showed an inhibition of cell growth over a time course of three days, with no change in cellular morphology. The effect of 20-hydroxyecdysone was enhanced in the presence of the potassium channel blocker 4-aminopyridine, but not tetraethylammonium. Concentration-response curves of 4-aminopyridine in the presence of 42 μM (1 mg/ml) 20-hydroxyecdysone showed similar IC50 values (6–10 μM) across 3 day exposures. Whole cell patch clamp confirmed the expression of delayed-rectifier (Kv2) potassium channels in hormone-supplemented Sua1B cells, whereas untreated Sua1B cells showed no evidence of Kv2 expression. The hormone-induced expression of Kv2 channels occurred in as little as 4 h after treatment, but were not observed after 24 h of exposure to 20-hydroxyecdysone, suggesting they played a role in cell death. The expressed channels had current-voltage relationships diagnostic for the Kv2 subtype, and were inhibited with an IC50 = 13 mM of tetraethylammonium. Overall, these parameters were similar to Anopheles gambiae Kv2 potassium channels expressed in HEK-293 cells. The induced presence of ion channels (and possibly receptors) in these cells has potential utility for high throughput screening and basic neuroscience research.
      Graphical abstract image

      PubDate: 2017-07-01T03:03:53Z
      DOI: 10.1016/j.ibmb.2017.06.012
       
  • Characterization of three serotonin receptors from the small white
           butterfly, Pieris rapae
    • Authors: Yi-xiang Qi; Miao Jin; Xu-yang Ni; Gong-yin Ye; Youngseok Lee; Jia Huang
      Abstract: Publication date: Available online 27 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yi-xiang Qi, Miao Jin, Xu-yang Ni, Gong-yin Ye, Youngseok Lee, Jia Huang
      Serotonin (5-hydroxytryptamine, 5-HT) plays a key role in modulating diverse physiological processes and behaviors in both protostomes and deuterostomes. These functions are mediated through the binding of serotonin to its receptors, which are recognized as potential insecticide targets. We investigated the sequence, pharmacology and tissue distribution of three 5-HT receptors (Piera5-HT1A, Piera5-HT1B, Piera5-HT7) from the small white butterfly Pieris rapae, an important pest of cultivated cabbages and other mustard family crops. Activation of Piera5-HT1A or Piera5-HT1B by 5-HT inhibited the production of cAMP in a dose-dependent manner. Stimulation of Piera5-HT7 with 5-HT increased cAMP level significantly. Surprisingly, with the exception of 5-methoxytryptamine, agonists including α-methylserotonin, 8-Hydroxy-DPAT and 5-carboxamidotryptamine activated these receptors poorly. The results are consistent with previous findings in Manduca sexta. All three receptors were blocked by methiothepin, but ketanserin and yohimbine were not effective. The selective mammalian 5-HT receptor antagonists SB 216641 and SB 269970 displayed potent inhibition effects on Piera5-HT1B and Piera5-HT7 respectively. The results we achieved here indicate that the pharmacological properties of Lepidoptera 5-HT receptors are quite different from those in other insects and vertebrates and may contribute to development of new selective pesticides. This study offers important information on three 5-HT receptors from P. rapae that will facilitate further analysis of the functions of 5-HT receptors in insects.
      Graphical abstract image

      PubDate: 2017-07-01T03:03:53Z
      DOI: 10.1016/j.ibmb.2017.06.011
       
  • Characterization and expression patterns of key ecdysteroid biosynthesis
           and signaling genes in a spider mite (Panonychus citri)
    • Authors: Gang Li; Jinzhi Niu; Moises Zotti; Qinzhe Sun; Lin Zhu; Jun Zhang; Chongyu Liao; Wei Dou; Dandan Wei; Jinjun Wang; Guy Smagghe
      Abstract: Publication date: Available online 20 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Gang Li, Jinzhi Niu, Moises Zotti, Qinzhe Sun, Lin Zhu, Jun Zhang, Chongyu Liao, Wei Dou, Dandan Wei, Jinjun Wang, Guy Smagghe
      Ecdysteroids play a crucial role in regulating molting in the phylum of Arthropoda and much is known with members of the subphylum of Hexapoda including the Insecta. However, this is still unclear in key pests as spider mites belonging to the subphylum of Chelicerata that originated earlier in the Cambrian period. In this study, we investigated 14 key genes of ecdysteroid biosynthesis and signaling and their expression over the different developmental stages in the citrus red mite, Panonychus citri (Acari: Stigmaeidae). P. citri is an economically important and widespread pest of citrus crops and it has five developmental stages of egg, larva, protonymph, deutonymph and adult. Typically, the expression of the ecdysteroid-synthesizing Halloween gene Spook (PcSpo) followed a positive zigzag-like pattern with a peak in the first half of each developmental stage and a drop in the second half prior to the molting to the next stage. Similar to PcSpo, PcDib, PcSad, PcRXR2, PcE75 and PcHR38 showed a positive zigzag-like expression pattern, while that of PcE78, PcHR3 and PcFTZ-F1 was opposite that we called a negative zigzag-like pattern. Silencing of the PcSpo gene by RNAi showed that molting was inhibited. Interestingly, we could rescue these RNAi effects by supplementing ponasterone A (PonA) and not by 20E, which is indicative that mites use PonA rather than 20E as ecdysteroid hormone. Modeling of the ecdysteroid receptor (PcEcR) hormone binding cavity also predicted binding of PonA, but showed a steric hindrance for 20E. We believe our data provide insight into the evolution and expression patterns of key ecdysteroid biosynthesis and signaling genes in a distant, non-insect species, and can become a foundation to develop new targets for controlling important agricultural pests such as spider mites.
      Graphical abstract image

      PubDate: 2017-06-22T06:16:05Z
      DOI: 10.1016/j.ibmb.2017.06.009
       
  • Genes encoding cuticular proteins are components of the Nimrod gene
           cluster in Drosophila
    • Authors: Gyöngyi Cinege; János Zsámboki; Maite Vidal-Quadras; Anne Uv; Gábor Csordás; Viktor Honti; Erika Gábor; Zoltán Hegedűs; Gergely I.B. Varga; Attila L. Kovács; Gábor Juhász; Michael J. Williams; István Andó; Éva Kurucz
      Abstract: Publication date: Available online 17 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Gyöngyi Cinege, János Zsámboki, Maite Vidal-Quadras, Anne Uv, Gábor Csordás, Viktor Honti, Erika Gábor, Zoltán Hegedűs, Gergely I.B. Varga, Attila L. Kovács, Gábor Juhász, Michael J. Williams, István Andó, Éva Kurucz
      The Nimrod gene cluster, located on the second chromosome of Drosophila melanogaster, is the largest synthenic unit of the Drosophila genome. Nimrod genes show blood cell specific expression and code for phagocytosis receptors that play a major role in fruit fly innate immune functions. We previously identified three homologous genes (vajk-1, vajk-2 and vajk-3) located within the Nimrod cluster, which are unrelated to the Nimrod genes, but are homologous to a fourth gene (vajk-4) located outside the cluster. Here we show that, unlike the Nimrod candidates, the Vajk proteins are expressed in cuticular structures of the late embryo and the late pupa, indicating that they contribute to cuticular barrier functions.
      Graphical abstract image

      PubDate: 2017-06-22T06:16:05Z
      DOI: 10.1016/j.ibmb.2017.06.006
       
  • Pharmacological characterisation and functional roles for egg-laying of a
           β-adrenergic-like octopamine receptor in the brown planthopper
           Nilaparvata lugens
    • Authors: Shun-Fan Wu; Xiao-Min Jv; Jian Li; Guang-Jian Xu; Xiao-Yi Cai; Cong-Fen Gao
      Abstract: Publication date: Available online 16 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Shun-Fan Wu, Xiao-Min Jv, Jian Li, Guang-Jian Xu, Xiao-Yi Cai, Cong-Fen Gao
      Octopamine, the invertebrate counterpart of adrenaline and noradrenaline, controls and modulates many physiological and behavioral processes in protostomes. It mediates its effects by binding to specific receptors belonging to the superfamily of G-protein coupled receptors. We report the cloning of a cDNA from the brown planthopper (Nloa2b2) sharing high similarity with members of the OA2B2 receptor class. Activation of NlOA2B2 by octopamine increased the production of cAMP in a dose-dependent manner (EC50 = 114 nM). Tyramine also activated the receptor but with much less potency than octopamine. Using a series of known agonists and antagonists of octopamine receptors and cAMP measurements, we observed a rather unique pharmacological profile of NlOA2B2. The potency ranking of the tested agonists was naphazoline > clonidine. The activated effect of octopamine is abolished by co-incubation with epinastine, mianserin, phentolamine, methiothepin, butaclamol or methysergide. Nloa2b2 was expressed in different developmental stages and in various tissues including female reproductive regions known to be involved in egg-laying behavior. Using in vivo pharmacology and RNAi methodology, we demonstrated that interference of NlOA2B2 signaling pathway had a strong impact on the egg-laying behavior of female brown planthopper. The data presented here mark the first comprehensive study—from gene to behavior—of a OA2B2 receptor in the rice brown planthopper.
      Graphical abstract image

      PubDate: 2017-06-22T06:16:05Z
      DOI: 10.1016/j.ibmb.2017.06.008
       
  • Severe developmental timing defects in the prothoracicotropic hormone
           (PTTH)-Deficient silkworm, Bombyx mori
    • Authors: Miwa Uchibori-Asano; Takumi Kayukawa; Hideki Sezutsu; Tetsuro Shinoda; Takaaki Daimon
      Abstract: Publication date: Available online 13 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Miwa Uchibori-Asano, Takumi Kayukawa, Hideki Sezutsu, Tetsuro Shinoda, Takaaki Daimon
      The insect neuropeptide prothoracicotropic hormone (PTTH) triggers the biosynthesis and release of the molting hormone ecdysone in the prothoracic gland (PG), thereby controlling the timing of molting and metamorphosis. Despite the well-documented physiological role of PTTH and its signaling pathway in the PG, it is not clear whether PTTH is an essential hormone for ecdysone biosynthesis and development. To address this question, we established and characterized a PTTH knockout line in the silkworm, Bombyx mori. We found that PTTH knockouts showed a severe developmental delay in both the larval and pupal stages. Larval phenotypes of PTTH knockouts can be classified into three major classes: (i) developmental arrest during the second larval instar, (ii) precocious metamorphosis after the fourth larval instar (one instar earlier in comparison to the control strain), and (iii) metamorphosis to normal-sized pupae after completing the five larval instar stages. In PTTH knockout larvae, peak levels of ecdysone titers in the hemolymph were dramatically reduced and the timing of peaks was delayed, suggesting that protracted larval development is a result of the reduced and delayed synthesis of ecdysone in the PG. Despite these defects, low basal levels of ecdysone were maintained in PTTH knockout larvae, suggesting that the primary role of PTTH is to upregulate ecdysone biosynthesis in the PG during molting stages, and low basal levels of ecdysone can be maintained in the absence of PTTH. We also found that mRNA levels of genes involved in ecdysone biosynthesis and ecdysteroid signaling pathways were significantly reduced in PTTH knockouts. Our results provide genetic evidence that PTTH is not essential for development, but is required to coordinate growth and developmental timing.
      Graphical abstract image

      PubDate: 2017-06-16T09:30:47Z
      DOI: 10.1016/j.ibmb.2017.06.007
       
  • Sex pheromone in the moth Heliothis virescens is produced as a mixture of
           two pools: de novo and via precursor storage in glycerolipids
    • Authors: Stephen P. Foster; Karin G. Anderson; Jérôme Casas
      Abstract: Publication date: Available online 12 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Stephen P. Foster, Karin G. Anderson, Jérôme Casas
      Most species of moths use a female-produced volatile sex pheromone, typically produced via de novo fatty acid synthesis in a specialized gland, for communication among mates. While de novo biosynthesis of pheromone (DNP) is rapid, suggesting transient precursor acids, substantial amounts of pheromone precursor (and other) acids are stored, predominantly in triacylglycerols in the pheromone gland. Whether these stored acids are converted to pheromone later or not has been the subject of some debate. Using a tracer/tracee approach, in which we fed female Heliothis virescens U-13C-glucose, we were able to distinguish two pools of pheromone, in which precursors were temporally separated (after and before feeding on labeled glucose): DNP synthesized from a mixed tracer/tracee acetyl CoA pool after feeding, and pheromone made from precursor acids primarily synthesized before feeding, which we call recycled precursor fat pheromone (RPP). DNP titer varied from high (during scotophase) to low (photophase) and with presence/absence of pheromone biosynthesis activating neuropeptide (PBAN), in accord with native pheromone titer previously observed. By contrast, RPP was constant throughout the photoperiod and did not change with PBAN presence/absence. The amount of RPP (6.3–10.3 ng/female) was typically much lower than that of DNP, especially during the scotophase (peak DNP, 105 ng/female). We propose an integral role for stored fats in pheromone biosynthesis, in which they are hydrolyzed and re-esterified throughout the photoperiod, with a small proportion of liberated precursor acyl CoAs being converted to pheromone. During the sexually active period, release of PBAN results in increased flux of glucose (from trehalose) and hydrolyzed acids entering the mitochondria, producing acetyl CoA precursor for de novo fat and pheromone biosynthesis.
      Graphical abstract image

      PubDate: 2017-06-16T09:30:47Z
      DOI: 10.1016/j.ibmb.2017.06.004
       
  • Insulin-like growth factor (IGF)-like peptide and 20-hydroxyecdysone
           regulate the growth and development of the male genital disk through
           different mechanisms in the silkmoth, Bombyx mori.
    • Authors: Daiki Fujinaga; Yusuke Kohmura; Naoki Okamoto; Hiroshi Kataoka; Akira Mizoguchi
      Abstract: Publication date: Available online 10 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Daiki Fujinaga, Yusuke Kohmura, Naoki Okamoto, Hiroshi Kataoka, Akira Mizoguchi
      It is well established that ecdysteroids play pivotal roles in the regulation of insect molting and metamorphosis. However, the mechanisms by which ecdysteroids regulate the growth and development of adult organs after pupation are poorly understood. Recently, we have identified insulin-like growth factor (IGF)-like peptides (IGFLPs), which are secreted after pupation under the control of 20-hydroxyecdysone (20E). In the silkmoth, Bombyx mori, massive amounts of Bombyx-IGFLP (BIGFLP) are present in the hemolymph during pupal-adult development, suggesting its importance in the regulation of adult tissue growth. Thus, we hypothesized that the growth and development of adult tissues including imaginal disks are regulated by the combined effects of BIGFLP and 20E. In this study, we investigated the growth-promoting effects of BIGFLP and 20E using the male genital disks of B. mori cultured ex vivo, and further analyzed the cell signaling pathways mediating hormone actions. We demonstrate that 20E induces the elongation of genital disks, that both hormones stimulate protein synthesis in an additive manner, and that BIGFLP and 20E exert their effects through the insulin/IGF signaling pathway and mitogen-activated protein kinase pathway, respectively. These results show that the growth and development of the genital disk are coordinately regulated by both BIGFLP and 20E.
      Graphical abstract image

      PubDate: 2017-06-11T17:12:28Z
      DOI: 10.1016/j.ibmb.2017.06.003
       
  • The ABC transporter ABCH-9C is needed for cuticle barrier construction in
           Locusta migratoria
    • Authors: Zhitao Yu; Yiwen Wang; Xiaoming Zhao; Xiaojian Liu; Enbo Ma; Bernard Moussian; Jianzhen Zhang
      Abstract: Publication date: Available online 10 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Zhitao Yu, Yiwen Wang, Xiaoming Zhao, Xiaojian Liu, Enbo Ma, Bernard Moussian, Jianzhen Zhang
      ATP-binding cassette (ABC) transporters constitute a large superfamily of proteins that mediate transport of a diverse number of substrates including nutrients, lipids and xenobiotics across membranes serving a variety of developmental and physiological functions. Here, we report on the molecular properties and biological roles of the ABC transporter LmABCH-9C in the migratory locust Locusta migratoria. LmABCH-9C was expressed continuously during nymphal development in all tissues including the integument. Expression was highest just after molting. Suppression of LmABCH-9C transcript levels by RNA interference (RNAi) in nymphs provoked death during or soon after molting to the next stage. These nymphs lost weight within minutes after molting. Moreover, high humidity rescued the lethality of molted LmABCH-9C-injected nymphs. In histological experiments, we find that the amounts of inner-cuticular lipids are reduced in nymphs with suppressed LmABCH-9C expression. These data together indicate that LmABCH-9C is needed for lipid-dependent desiccation resistance, paralleling the function of ABCH-9C in Tribolium castaneum. Hence, the function of this ABC transporter seems to be conserved across insect species ranging from hemimetabolous (L. migratoria) to holometabolous (T. castaneum) species. In addition, we find that cuticle inward impermeability is compromised in nymphs with reduced LmABCH-9C function. In summary, consistent with the model that cuticular lipids are necessary to prevent desiccation and penetration of xenobiotics in insects, we hypothesize that LmABCH-9C is involved in the construction of a lipid-based barrier at the surface of the cuticle especially after molting to protect the animal against uncontrolled water loss and entry. Susceptibility of this ABC transporter to RNAi-mediated knockdown designates it as an excellent target for RNAi-based insect pest control.
      Graphical abstract image

      PubDate: 2017-06-11T17:12:28Z
      DOI: 10.1016/j.ibmb.2017.06.005
       
  • Transcriptional signatures of parasitization and markers of colony decline
           in Varroa-infested honey bees (Apis mellifera)
    • Authors: Virginia Zanni; David A. Galbraith; Desiderato Annoscia; Christina M. Grozinger; Francesco Nazzi
      Abstract: Publication date: Available online 5 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Virginia Zanni, David A. Galbraith, Desiderato Annoscia, Christina M. Grozinger, Francesco Nazzi
      Extensive annual losses of honey bee colonies (Apis mellifera L.) reported in the northern hemisphere represent a global problem for agriculture and biodiversity. The parasitic mite Varroa destructor, in association with deformed wing virus (DWV), plays a key role in this phenomenon, but the underlying mechanisms are still unclear. To elucidate these mechanisms, we analyzed the gene expression profile of uninfested and mite infested bees, under laboratory and field conditions, highlighting the effects of parasitization on the bee's transcriptome under a variety of conditions and scenarios. Parasitization was significantly correlated with higher viral loads. Honey bees exposed to mite infestation exhibited an altered expression of genes related to stress response, immunity, nervous system function, metabolism and behavioural maturation. Additionally, mite infested young bees showed a gene expression profile resembling that of forager bees. To identify potential molecular markers of colony decline, the expression of genes that were commonly regulated across the experiments were subsequently assessed in colonies experiencing increasing mite infestation levels. These studies suggest that PGRP-2, hymenoptaecin, a glucan recognition protein, UNC93 and a p450 cytocrome maybe be suitable general biomarkers of Varroa-induced colony decline. Furthermore, the reliability of vitellogenin, a yolk protein previously identified as a good marker of colony survival, was confirmed here.
      Graphical abstract image

      PubDate: 2017-06-06T16:21:58Z
      DOI: 10.1016/j.ibmb.2017.06.002
       
 
 
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