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  Subjects -> BIOLOGY (Total: 2987 journals)
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BIOCHEMISTRY (232 journals)                  1 2 | Last

Showing 1 - 200 of 232 Journals sorted alphabetically
AAPS PharmSciTech     Hybrid Journal   (Followers: 6)
Acetic Acid Bacteria     Open Access   (Followers: 2)
ACS Central Science     Open Access   (Followers: 6)
ACS Chemical Biology     Full-text available via subscription   (Followers: 237)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 17)
Acta Crystallographica Section D : Biological Crystallography     Hybrid Journal   (Followers: 8)
Acta Crystallographica Section F: Structural Biology Communications     Hybrid Journal   (Followers: 7)
Advances and Applications in Bioinformatics and Chemistry     Open Access   (Followers: 9)
Advances in Biological Chemistry     Open Access   (Followers: 7)
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: 19)
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: 66)
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: 7)
Analytical Biochemistry     Hybrid Journal   (Followers: 161)
Angiogenesis     Hybrid Journal   (Followers: 3)
Annals of Clinical Biochemistry     Hybrid Journal   (Followers: 7)
Annual Review of Biochemistry     Full-text available via subscription   (Followers: 53)
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)
Avicenna Journal of Medical Biochemistry     Open Access  
Bangladesh Journal of Medical Biochemistry     Open Access   (Followers: 2)
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: 15)
Biochemical Genetics     Hybrid Journal   (Followers: 3)
Biochemical Journal     Full-text available via subscription   (Followers: 25)
Biochemical Pharmacology     Hybrid Journal   (Followers: 9)
Biochemical Society Transactions     Full-text available via subscription   (Followers: 4)
Biochemical Systematics and Ecology     Hybrid Journal   (Followers: 3)
Biochemistry     Full-text available via subscription   (Followers: 283)
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: 8)
Biochimie     Hybrid Journal   (Followers: 7)
Biochimie Open     Open Access  
Bioconjugate Chemistry     Full-text available via subscription   (Followers: 29)
BioDrugs     Full-text available via subscription   (Followers: 7)
Bioelectrochemistry     Hybrid Journal   (Followers: 2)
Biofuels     Hybrid Journal   (Followers: 10)
Biogeochemistry     Hybrid Journal   (Followers: 13)
BioInorganic Reaction Mechanisms     Hybrid Journal   (Followers: 1)
Biokemistri     Open Access  
Biological Chemistry     Partially Free   (Followers: 22)
Biomaterials Research     Open Access   (Followers: 4)
Biomedicines     Open Access   (Followers: 1)
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  
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: 6)
Chemical and Biological Technologies for Agriculture     Open Access  
Chemical Biology & Drug Design     Hybrid Journal   (Followers: 20)
Chemical Engineering Journal     Hybrid Journal   (Followers: 34)
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: 67)
Clinical Chemistry and Laboratory Medicine     Hybrid Journal   (Followers: 59)
Clinical Lipidology     Full-text available via subscription   (Followers: 1)
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology     Hybrid Journal   (Followers: 5)
Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 2)
Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology     Hybrid Journal   (Followers: 8)
Comparative Biochemistry and Physiology Part D: Genomics and Proteomics     Hybrid Journal   (Followers: 3)
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: 15)
Current Opinion in Chemical Biology     Hybrid Journal   (Followers: 26)
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: 55)
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: 9)
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: 2)
Journal of Biochemistry     Hybrid Journal   (Followers: 43)
Journal of Biological Chemistry     Full-text available via subscription   (Followers: 191)
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: 1)
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     Hybrid Journal   (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: 7)
Journal of Neurochemistry     Hybrid Journal   (Followers: 3)
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: 7)
La Rivista Italiana della Medicina di Laboratorio - Italian Journal of Laboratory Medicine     Hybrid Journal  
Lab on a Chip     Full-text available via subscription   (Followers: 34)
Marine Chemistry     Hybrid Journal   (Followers: 6)
Methods in Enzymology     Full-text available via subscription   (Followers: 11)
Molecular and Biochemical Parasitology     Hybrid Journal   (Followers: 2)
Molecular and Cellular Biochemistry     Hybrid Journal   (Followers: 6)
Molecular Aspects of Medicine     Hybrid Journal   (Followers: 2)
Molecular Informatics     Hybrid Journal   (Followers: 6)
Molecular inhibitors in targeted therapy     Open Access  
Moscow University Chemistry Bulletin     Hybrid Journal   (Followers: 1)
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: 71)
Nature Communications     Open Access   (Followers: 176)
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: 3)
Organic & Biomolecular Chemistry     Full-text available via subscription   (Followers: 90)
Peptidomics     Open Access  
Pesticide Biochemistry and Physiology     Hybrid Journal   (Followers: 4)
Pflugers Archiv European Journal of Physiology     Hybrid Journal   (Followers: 3)

        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  [3034 journals]
  • Wolbachia-induced loss of male fertility is likely related to branch chain
           amino acid biosynthesis and iLvE in Laodelphax striatellus
    • Authors: Jia-Fei Ju; Ary A. Hoffmann; Yan-Kai Zhang; Xing-Zhi Duan; Yan Guo; Jun-Tao Gong; Wen-Chao Zhu; Xiao-Yue Hong
      Pages: 11 - 20
      Abstract: Publication date: June 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 85
      Author(s): Jia-Fei Ju, Ary A. Hoffmann, Yan-Kai Zhang, Xing-Zhi Duan, Yan Guo, Jun-Tao Gong, Wen-Chao Zhu, Xiao-Yue Hong
      Wolbachia are endosymbionts that infect many species of arthropods and nematodes. Wolbachia-induced cytoplasmic incompatibility (CI) is the most common phenotype in affected hosts, involving embryonic lethality in crosses between Wolbachia-infected males and uninfected females. The molecular mechanisms underlying this phenomenon are currently unclear. Here we examine the molecular correlates of the Wolbachia infection in Laodelphax striatellus (Fallén), an important rice pest, where embryonic lethality is strong and almost complete. We compared the gene expression of 4-day-old Wolbachia-infected and uninfected L. striatellus testes to identify candidate genes for paternal-effect embryonic lethality induction. Based on microarray analysis, iLvE was the most down-regulated gene; this gene mediates branched-chain amino acid (BCAA) biosynthesis and participates in many processes related to reproductive performance. After knocking down iLvE by RNAi in uninfected male L. striatellus, male fertility was reduced, leading to a decrease in embryo hatching rates, but fertility was rescued in crosses between these males and Wolbachia-infected females. Removal of BCAA in chemically-defined diets of uninfected males also led to a loss of male fertility. Low amino acid nutrition may enhance exposure time of sperm to Wolbachia in the testes to affect adult reproduction in L. striatellus by reducing the number of sperm transferred per mating by males. These results indicate that Wolbachia may decrease male fertility in L. striatellus by acting on iLvE, a key factor of BCAA biosynthesis, and delaying sperm maturation.
      Graphical abstract image

      PubDate: 2017-04-18T10:38:55Z
      DOI: 10.1016/j.ibmb.2017.04.002
      Issue No: Vol. 85 (2017)
       
  • Corrigendum to “Functional and immunohistochemical characterization of
           CCEae3a, a carboxylesterase associated with temephos resistance in the
           major arbovirus vectors Aedes aegypti and Ae. albopictus” [Insect
           Biochem. Mol. Biol. 74 (July 2016) 61–67]
    • Authors: Linda Grigoraki; Vassileia Balabanidou; Christos Meristoudis; Antonis Miridakis; Hilary Ranson; Luc Swevers; John Vontas
      First page: 32
      Abstract: Publication date: June 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 85
      Author(s): Linda Grigoraki, Vassileia Balabanidou, Christos Meristoudis, Antonis Miridakis, Hilary Ranson, Luc Swevers, John Vontas


      PubDate: 2017-06-02T15:59:04Z
      DOI: 10.1016/j.ibmb.2017.05.003
      Issue No: Vol. 85 (2017)
       
  • Success in the acquisition of Bombyx mori sperm motility is influenced by
           the extracellular production of nitric oxide (NO) in the presence of
           seminal fluid nitric oxide synthetase (NOS)
    • Authors: Sumiharu Nagaoka; Maiko Asagoshi; Keita Kato; Yuki Takata
      Pages: 40 - 47
      Abstract: Publication date: Available online 13 April 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Sumiharu Nagaoka, Maiko Asagoshi, Keita Kato, Yuki Takata
      A trypsin-like protease called initiatorin is known to initiate sperm motility in the silkworm, Bombyx mori, but little is known about the signaling events leading to sperm flagellar beating. The aim of this study was to investigate whether this mechanism of sperm motility activation involves the signaling transmitter nitric oxide (NO). NO is produced from the amino acid L-arginine by the enzyme action of nitric oxide synthase (NOS; EC 1.14.13.39). Simple treatment of quiescent sperm with an NO donor (SNAP or NOC7) in vitro did not lead to activation of motility. Nevertheless, initiatorin- or trypsin-induced motility was blocked by pretreatment of sperm with either the NOS inhibitor L-NAME or NO scavenger carboxy-PTIO. These observations suggested that NO may play important physiological roles in the acquisition of sperm motility under the in vitro condition used here. Then, we investigated whether NO synthesis would occur in the spermatophore, a capsule containing spermatozoa that is created by the contents of various male reproductive glands and is the site of sperm maturation. The amounts of NO2 − and NO3 −, stable metabolites of NO, reached maximum values after enclosure in the spermatophore, a time when apyrene spermatozoa acquire vigorous motility. Moreover, RT-PCR and Western blotting analyses of NOS indicated that it is abundantly expressed in glandula (g.) lacteola of the virgin male ejaculatory duct, from which it is secreted to the seminal fluid and transferred to the female during mating. Previous studies demonstrated that free L-arginine is supplied de novo by a specific proteolytic reaction in which initiatorin participates during spermatophore formation (Osanai et al., 1987c). Based on these results, it can be presumed that the mixing of seminal fluid contents from each male reproductive organ during ejaculation induced NO production outside of the spermatid, and exogenous NO stimulated a signaling pathway involved in the activation of silkworm apyrene sperm.
      Graphical abstract image

      PubDate: 2017-04-18T10:38:55Z
      DOI: 10.1016/j.ibmb.2017.04.003
      Issue No: Vol. 84 (2017)
       
  • Prophenoloxidase activation and antimicrobial peptide expression induced
           by the recombinant microbe binding protein of Manduca sexta
    • Authors: Yang Wang; Haobo Jiang
      Pages: 35 - 43
      Abstract: Publication date: April 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 83
      Author(s): Yang Wang, Haobo Jiang
      Manduca sexta microbe binding protein (MBP) is a member of the β-1,3-glucanase-related protein superfamily that includes Gram-negative bacteria-binding proteins (GNBPs), β-1,3-glucan recognition proteins (βGRPs), and β-1,3-glucanases. Our previous and current studies showed that the purified MBP from baculovirus-infected insect cells had stimulated prophenoloxidase (proPO) activation in the hemolymph of naïve and immune challenged larvae and that supplementation of the exogenous MBP and peptidoglycans (PGs) had caused synergistic increases in PO activity. To explore the underlying mechanism, we separated by SDS-PAGE naïve and induced larval plasma treated with buffer or MBP and detected on immunoblots changes in intensity and/or mobility of hemolymph (serine) proteases [HP14, HP21, HP6, HP8, proPO-activating proteases (PAPs) 1–3] and their homologs (SPH1, SPH2). In a nickel pull-down assay, we observed association of MBP with proHP14 (slightly), βGRP2, PG recognition protein-1 (PGRP1, indirectly), SPH1, SPH2, and proPO2. Further experiments indicated that diaminopimelic acid (DAP) or Lys PG, MBP, PGRP1, and proHP14 together trigger the proPO activation system in a Ca2+-dependent manner. Injection of the recombinant MBP into the 5th instar naïve larvae significantly induced the expression of several antimicrobial peptide genes, revealing a possible link between HP14 and immune signal transduction. Together, these results suggest that the recognition of Gram-negative or -positive bacteria via their PGs induces the melanization and Toll pathways in M. sexta.
      Graphical abstract image

      PubDate: 2017-02-24T04:13:05Z
      DOI: 10.1016/j.ibmb.2016.10.006
      Issue No: Vol. 83 (2017)
       
  • Pharmacological characterization of dopamine receptors in the rice striped
           stem borer, Chilo suppressalis
    • Authors: Gang Xu; Shun-Fan Wu; Gui-Xiang Gu; Zi-Wen Teng; Gong-Yin Ye; Jia Huang
      Pages: 80 - 93
      Abstract: Publication date: April 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 83
      Author(s): Gang Xu, Shun-Fan Wu, Gui-Xiang Gu, Zi-Wen Teng, Gong-Yin Ye, Jia Huang
      Dopamine is an important neurotransmitter and neuromodulator in both vertebrates and invertebrates and is the most abundant monoamine present in the central nervous system of insects. A complement of functionally distinct dopamine receptors mediate the signal transduction of dopamine by modifying intracellular Ca2+ and cAMP levels. In the present study, we pharmacologically characterized three types of dopamine receptors, CsDOP1, CsDOP2 and CsDOP3, from the rice striped stem borer, Chilo suppressalis. All three receptors show considerable sequence identity with orthologous dopamine receptors. The phylogenetic analysis also clusters the receptors within their respective groups. Transcript levels of CsDOP1, CsDOP2 and CsDOP3 were all expressed at high levels in the central nervous system, indicating their important roles in neural processes. After heterologous expression in HEK 293 cells, CsDOP1, CsDOP2 and CsDOP3 were dose-dependently activated by dopamine and synthetic dopamine receptor agonists. They can also be blocked by different series of antagonists. This study offers important information on three dopamine receptors from C. suppressalis that will provide the basis for forthcoming studies investigating their roles in behaviors and physiology, and facilitate the development of new insecticides for pest control.
      Graphical abstract image

      PubDate: 2017-03-21T08:28:43Z
      DOI: 10.1016/j.ibmb.2017.03.004
      Issue No: Vol. 83 (2017)
       
  • Cathepsin L participates in the remodeling of the midgut through
           dissociation of midgut cells and activation of apoptosis via caspase-1
    • Authors: Cui Yang; Xian-Wu Lin; Wei-Hua Xu
      Pages: 21 - 30
      Abstract: Publication date: March 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 82
      Author(s): Cui Yang, Xian-Wu Lin, Wei-Hua Xu
      The larval midgut in holometabolous insects must undergo a remodeling process during metamorphosis to form the pupal-adult midgut. However, the molecular mechanism of larval midgut cell dissociation remains unknown. Here, we show that the expression and activity of Helicoverpa armigera cathepsin L (Har-CatL) are high in the midgut at the mid-late stage of the 6th-instar larvae and are responsive to the upstream hormone ecdysone. Immunocytochemistry shows that signals for Har-CatL-like are localized in midgut cells, and an inhibitor experiment demonstrates that Har-CatL functions in the dissociation of midgut epithelial cells. Mechanistically, Har-CatL can cleave pro-caspase-1 into the mature peptide, thereby increasing the activity of caspase-1, which plays a key role in apoptosis, indicating that Har-CatL is also involved in the apoptosis of midgut cells by activating caspase-1. We believe that this is the first report that Har-CatL regulates the dissociation and apoptosis of the larval midgut epithelium for midgut remodeling.
      Graphical abstract image

      PubDate: 2017-02-04T23:04:10Z
      DOI: 10.1016/j.ibmb.2017.01.010
      Issue No: Vol. 82 (2017)
       
  • The immune properties of Manduca sexta transferrin
    • Authors: Lisa M. Brummett; Michael R. Kanost; Maureen J. Gorman
      Pages: 1 - 9
      Abstract: Publication date: February 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 81
      Author(s): Lisa M. Brummett, Michael R. Kanost, Maureen J. Gorman
      Transferrins are secreted proteins that bind iron. The well-studied transferrins are mammalian serum transferrin, which is involved in iron transport, and mammalian lactoferrin, which functions as an immune protein. Lactoferrin and lactoferrin-derived peptides have bactericidal activity, and the iron-free form of lactoferrin has bacteriostatic activity due to its ability to sequester iron. Insect transferrin is similar in sequence to both serum transferrin and lactoferrin, and its functions are not well-characterized; however, many studies of insect transferrin indicate that it has some type of immune function. The goal of this study was to determine the specific immune functions of transferrin from Manduca sexta (tobacco hornworm). We verified that transferrin expression is upregulated in response to infection in M. sexta larvae and determined that the concentration of transferrin in hemolymph increases from 2 μM to 10 μM following an immune challenge. It is also present in molting fluid and prepupal midgut fluid, two extracellular fluids with immune capabilities. No immune-induced proteolytic cleavage of transferrin in hemolymph was observed; therefore, M. sexta transferrin does not appear to be a source of antimicrobial peptides. Unlike iron-saturated lactoferrin, iron-saturated transferrin had no detectable antibacterial activity. In contrast, 1 μM iron-free transferrin inhibited bacterial growth, and this inhibition was blocked by supplementing the culture medium with 1 μM iron. Our results suggest that M. sexta transferrin does not have bactericidal activity, but that it does have a bacteriostatic function that depends on its iron sequestering ability. This study supports the hypothesis that insect transferrin participates in an iron withholding strategy to protect insects from infectious bacteria.
      Graphical abstract image

      PubDate: 2017-01-08T08:48:33Z
      DOI: 10.1016/j.ibmb.2016.12.006
      Issue No: Vol. 81 (2017)
       
  • 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
       
  • Quantitative proteomic analysis of the fall armyworm saliva
    • Authors: Flor E. Acevedo; Bruce A. Stanley; Anne Stanley; Michelle Peiffer; Dawn Luthe; Gary Felton
      Abstract: Publication date: Available online 4 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Flor E. Acevedo, Bruce A. Stanley, Anne Stanley, Michelle Peiffer, Dawn Luthe, Gary Felton
      Lepidopteran larvae secrete saliva on plant tissues during feeding. Components in the saliva may aid in food digestion, whereas other components are recognized by plants as cues to elicit defense responses. Despite the ecological and economical importance of these plant-feeding insects, knowledge of their saliva composition is limited to a few species. In this study, we identified the salivary proteins of larvae of the fall armyworm (FAW), Spodoptera frugiperda; determined qualitative and quantitative differences in the salivary proteome of the two host races—corn and rice strains—of this insect; and identified changes in total protein concentration and relative protein abundance in the saliva of FAW larvae associated with different host plants. Quantitative proteomic analyses were performed using labeling with isobaric tags for relative and absolute quantification followed by liquid chromatography-tandem mass spectrometry. In total, 98 proteins were identified (>99% confidence) in the FAW saliva. These proteins were further categorized into five functional groups: proteins potentially involved in (1) plant defense regulation, (2) herbivore offense, (3) insect immunity, (4) detoxification, (5) digestion, and (6) other functions. Moreover, there were differences in the salivary proteome between the FAW strains that were identified by label-free proteomic analyses. Thirteen differentially identified proteins were present in each strain. There were also differences in the relative abundance of eleven salivary proteins between the two FAW host strains as well as differences within each strain associated with different diets. The total salivary protein concentration was also different for the two strains reared on different host plants. Based on these results, we conclude that the FAW saliva contains a complex mixture of proteins involved in different functions that are specific for each strain and its composition can change plastically in response to diet type.
      Graphical abstract image

      PubDate: 2017-06-06T16:21:58Z
      DOI: 10.1016/j.ibmb.2017.06.001
       
  • A double-stranded RNA degrading enzyme reduces the efficiency of oral RNA
           interference in migratory locust
    • Authors: Huifang Song; Jianqin Zhang; Daqi Li; Anastasia M.W. Cooper; Kristopher Silver; Tao Li; Xiaojian Liu; Enbo Ma; Kun Yan Zhu; Jianzhen Zhang
      Abstract: Publication date: Available online 31 May 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Huifang Song, Jianqin Zhang, Daqi Li, Anastasia M.W. Cooper, Kristopher Silver, Tao Li, Xiaojian Liu, Enbo Ma, Kun Yan Zhu, Jianzhen Zhang
      Application of RNA interference (RNAi) for insect pest management is limited by variable efficiency of RNAi in different insect species. In Locusta migratoria, RNAi is highly efficient through injection of dsRNA, but oral delivery of dsRNA is much less effective. Efforts to understand this phenomenon have shown that dsRNA is more rapidly degraded in midgut fluid than in hemolymph due to nuclease enzyme activity. In the present study, we identified and characterized two full-length cDNAs of double-stranded RNA degrading enzymes (dsRNase) from midgut of L. migratoria, which were named LmdsRNase2 and LmdsRNase3. Gene expression analysis revealed that LmdsRNase2 and LmdsRNase3 were predominantly expressed in the midgut, relatively lower expression in gastric caeca, and trace expression in other tested tissues. Incubation of dsRNA in midgut fluid from LmdsRNase3-suppressed larvae or control larvae injected with dsGFP resulted in high levels of degradation; however, dsRNA incubated in midgut fluid from LmdsRNase2-suppressed larvae was more stable, indicating LmdsRNase2 is responsible for dsRNA degradation in the midgut. To verify the biological function of LmdsRNase2 in vivo, nymphs were injected with dsGFP, dsLmdsRNase2 or dsLmdsRNase3 and subsequently oral delivered chitinase 10 (LmCht10) or chitin synthase 1 (LmCHS1) dsRNA. Mortality associated with reporter gene knockdown was observed only in locusts injected with dsLmdsRNase2 (48% and 22%, for dsLmCht10 and dsLmCHS1, respectively), implicating LmdsRNase2 in reducing RNAi efficiency. Furthermore, recombinantly expressed LmdsRNase2 fusion proteins degraded dsRNA rapidly, whereas LmdsRNase3 did not. These results suggest that rapid degradation of dsRNA by dsRNase2 in the midgut is an important factor causing low RNAi efficiency when dsRNA is orally delivered in the locust.
      Graphical abstract image

      PubDate: 2017-06-02T15:59:04Z
      DOI: 10.1016/j.ibmb.2017.05.008
       
  • Intra- and extracellular domains of the Helicoverpa armigera cadherin
           mediate Cry1Ac cytotoxicity
    • Authors: Haonan Zhang; Shan Yu; Yu Shi; Yihua Yang; Jeffrey A. Fabrick; Yidong Wu
      Abstract: Publication date: Available online 31 May 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Haonan Zhang, Shan Yu, Yu Shi, Yihua Yang, Jeffrey A. Fabrick, Yidong Wu
      Diverse midgut cadherin mutations confer resistance to Cry1A toxins in at least three lepidopteran pests, including the cotton bollworm, Helicoverpa armigera. Most of these cadherin mutations are inherited as recessive alleles and result in changes within the cadherin repeat (CR) regions of the extracellular protein domain. However, the H. armigera r 15 cadherin mutation results in a deletion of 55 amino acid residues within the cytoplasmic domain, and Cry1A resistance is inherited as a non-recessive trait. Here, eight recombinant H. armigera cadherin (HaCad) proteins, including seven variants containing different combinations of CRs and the cytoplasmic domain, were expressed in cultured insect cells using a baculovirus expression system and were analyzed for Cry1Ac binding and toxicity. Cells expressing either the wild-type HaCad or a mutant lacking only the region corresponding to the first nine CRs bound Cry1Ac and were equally susceptible to Cry1Ac. Cells expressing mutant HaCad proteins without the Cry1A toxin binding region (TBR) located in the CR nearest the plasma membrane did not bind Cry1Ac and were not killed by the toxin. Among the mutant proteins, loss of toxicity was observed in all cells producing HaCad variants lacking the amino acids 1422–1440, indicating that this TBR motif is important for both toxin binding and to confer susceptibility to Cry1Ac. Cells expressing the HaCad variant lacking the entire cytoplasmic domain retained Cry1Ac binding, but were significantly less susceptible to Cry1Ac than were cells producing either wild-type HaCad or HaCad lacking the first nine CRs. These results suggest that both the extracellular and the cytoplasmic domains of HaCad participate in Cry1Ac intoxication.
      Graphical abstract image

      PubDate: 2017-06-02T15:59:04Z
      DOI: 10.1016/j.ibmb.2017.05.004
       
  • Mutations on M3 helix of Plutella xylostella glutamate-gated chloride
           channel confer unequal resistance to abamectin by two different mechanisms
           
    • Authors: Xingliang Wang; Alin M. Puinean; Andrias O. O´Reilly; Martin S. Williamson; Charles L.C. Smelt; Neil S. Millar; Yidong Wu
      Abstract: Publication date: Available online 31 May 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Xingliang Wang, Alin M. Puinean, Andrias O. O´Reilly, Martin S. Williamson, Charles L.C. Smelt, Neil S. Millar, Yidong Wu
      Abamectin is one of the most widely used avermectins for agricultural pests control, but the emergence of resistance around the world is proving a major threat to its sustained application. Abamectin acts by directly activating glutamate-gated chloride channels (GluCls) and modulating other Cys-loop ion channels. To date, three mutations occurring in the transmembrane domain of arthropod GluCls are associated with target-site resistance to abamectin: A309V in Plutella xylostella GluCl (PxGluCl), G323D in Tetranychus urticae GluCl1 (TuGluCl1) and G326E in TuGluCl3. To compare the effects of these mutations in a single system, A309V/I/G and G315E (corresponding to G323 in TuGluCl1 and G326 in TuGluCl3) substitutions were introduced individually into the PxGluCl channel. Functional analysis using Xenopus oocytes showed that the A309V and G315E mutations reduced the sensitivity to abamectin by 4.8- and 493-fold, respectively. In contrast, the substitutions A309I/G show no significant effects on the response to abamectin. Interestingly, the A309I substitution increased the channel sensitivity to glutamate by one order of magnitude (∼12-fold). Analysis of PxGluCl homology models indicates that the G315E mutation interferes with abamectin binding through a steric hindrance mechanism. In contrast, the structural consequences of the A309 mutations are not so clear and an allosteric modification of the binding site is the most likely mechanism. Overall the results show that both A309V and G315E mutations may contribute to target-site resistance to abamectin and may be important for the future prediction and monitoring of abamectin resistance in P. xylostella and other arthropod pests.
      Graphical abstract image

      PubDate: 2017-06-02T15:59:04Z
      DOI: 10.1016/j.ibmb.2017.05.006
       
  • Deletion of the Bombyx mori odorant receptor co-receptor (BmOrco) impairs
           olfactory sensitivity in silkworms
    • Authors: Qun Liu; Wei Liu; Baosheng Zeng; Guirong Wang; Dejun Hao; Yongping Huang
      Abstract: Publication date: Available online 31 May 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Qun Liu, Wei Liu, Baosheng Zeng, Guirong Wang, Dejun Hao, Yongping Huang
      Olfaction plays an essential role in many important insect behaviors such as feeding and reproduction. To detect olfactory stimuli, an odorant receptor co-receptor (Orco) is required. In this study, we deleted the Orco gene in the Lepidopteran model insect, Bombyx mori, using a binary transgene-based clustered regulatory interspaced short palindromic repeats (CRISPR)/Cas9 system. We initially generated somatic mutations in two targeted sites, from which we obtained homozygous mutants with deletion of a 866 base pair sequence. Because of the flight inability of B. mori, we developed a novel method to examine the adult mating behavior. Considering the specialization in larval feeding, we examined food selection behavior in Orco somatic mutants by the walking trail analysis of silkworm position over time. Single sensillum recordings indicated that the antenna of the homozygous mutant was unable to respond to either of the two sex pheromones, bombykol or bombykal. An adult mating behavior assay revealed that the Orco mutant displayed a significantly impaired mating selection behavior in response to natural pheromone released by a wild-type female moth as well as an 11:1 mixture of bombykol/bombykal. The mutants also exhibited a decreased response to bombykol and, similar to wild-type moths, they displayed no response to bombykal. A larval feeding behavior assay revealed that the Orco mutant displayed defective selection for mulberry leaves and different concentrations of the volatile compound cis-jasmone found in mulberry leaves. Deletion of BmOrco severely disrupts the olfactory system, suggesting that BmOrco is indispensable in the olfactory pathway. The approach used for generating somatic and homozygous mutations also highlights a novel method for mutagenesis. This study on BmOrco function provides insights into the insect olfactory system and also provides a paradigm for agroforestry pest control.
      Graphical abstract image

      PubDate: 2017-06-02T15:59:04Z
      DOI: 10.1016/j.ibmb.2017.05.007
       
  • C-type lectin interacting with β-integrin enhances hemocytic
           encapsulation in the cotton bollworm, Helicoverpa armigera
    • Authors: Pan Wang; Xiao-Rong Zhuo; Lin Tang; Xu-Sheng Liu; Yu-Feng Wang; Guo-Xiu Wang; Xiao-Qiang Yu; Jia-Lin Wang
      Abstract: Publication date: Available online 29 May 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Pan Wang, Xiao-Rong Zhuo, Lin Tang, Xu-Sheng Liu, Yu-Feng Wang, Guo-Xiu Wang, Xiao-Qiang Yu, Jia-Lin Wang
      The encapsulation reaction in invertebrates is analogous to granuloma formation in vertebrates, and this reaction is severely compromised when ecdysone signaling is blocked. However, the molecular mechanism underlying the encapsulation reaction and its regulation by ecdysone remains obscure. In our previous study, we found that the C-type lectin HaCTL3, from the cotton bollworm Helicoverpa armigera, is involved in anti-bacterial immune response, acting as a pattern recognition receptor (PRR). In the current study, we demonstrate that HaCTL3 is involved in defense against parasites and directly binds to the surface of nematodes. Our in vitro and in vivo studies indicate that HaCTL3 enhances hemocytic encapsulation and melanization, whereas H. armigera β-integrin (Haβ-integrin), located on the surface of hemocytes, participates in encapsulation. Additionally, co-immunoprecipitation experiments reveal HaCTL3 interacts with Haβ-integrin, and knockdown of Haβ-integrin leads to reduced encapsulation of HaCTL3-coated beads. These results indicate that Haβ-integrin serves as a hemocytic receptor of HaCTL3 during the encapsulation reaction. Furthermore, we demonstrate that 20-hydroxyecdysone (20E) treatment dramatically induces the expression of HaCTL3, and knockdown of the 20E receptor (EcR)/ultraspiracle (USP), abrogates this response. Overall, this study provides the first evidence of the presence of a hemocytic receptor (Haβ-integrin), that interacts with the PRR HaCTL3 to facilitate encapsulation reaction in insects and demonstrates the regulation of this process by the steroid hormone ecdysone.
      Graphical abstract image

      PubDate: 2017-06-02T15:59:04Z
      DOI: 10.1016/j.ibmb.2017.02.004
       
  • Functional analysis of TcCTLP-5C2, a chymotrypsin-like serine protease
           needed for molting in Tribolium castaneum
    • Authors: Daniel Albaum; Gunnar Broehan; Subbaratnam Muthukrishnan; Hans Merzendorfer
      Abstract: Publication date: Available online 15 May 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Daniel Albaum, Gunnar Broehan, Subbaratnam Muthukrishnan, Hans Merzendorfer
      In a previous study, we have characterized a gene family encoding chymotrypsin-like proteases from the red flour beetle, Tribolium castaneum (TcCTLPs). We identified 14 TcCTLP genes that were predominantly expressed in the midgut, where they presumably function in digestion. Two genes (TcCTLP-6C and TcCTLP-5C 2 ), however, additionally showed considerable expression in the carcass, and RNAi studies demonstrated that they are required for molting (Broehan et al., 2010; Insect Biochem. Mol. Biol 40, 274-83). Thus, the enzyme has distinct functions in different physiological environments. To study molecular adaptations that facilitate enzyme function in different environments, we performed an in-depth analysis of the molecular and enzymatic properties of TcCTLP-5C2. We expressed different mutated versions of TcCTLP-5C2 in form of factor Xa activatable pro-enzymes in insect cells using a baculoviral expression system, and purified the recombinant proteins by affinity chromatography. By measuring and comparing the enzyme activities, we obtained information about the significance of single amino acid residues in motifs that determine substrate specificity and pH tolerance. Further, we showed that TcCTLP-5C2 is modified by N-glycosylation at amino acid position N137, which lies opposite to the catalytic cleft. Comparison of the enzymatic properties of non-glycosylated and glycosylated TcCTLP-5C2 versions showed that N-glycosylation decreases Vmax (maximum velocity) and kcat (turnover) while leaving the Km (specificity) unchanged. Thus, we provide evidence that N-glycosylation alters catalytic behavior by allosteric effects presumably due to altered structural dynamics as observed for chemically glycosylated enzymes.
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      PubDate: 2017-05-17T14:08:22Z
      DOI: 10.1016/j.ibmb.2017.05.002
       
  • DINeR: Database for Insect Neuropeptide Research
    • Authors: Joseph G.C. Yeoh; Aniruddha A. Pandit; Meet Zandawala; Dick R. Nässel; Shireen-Anne Davies; Julian A.T. Dow
      Abstract: Publication date: Available online 11 May 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Joseph G.C. Yeoh, Aniruddha A. Pandit, Meet Zandawala, Dick R. Nässel, Shireen-Anne Davies, Julian A.T. Dow
      Neuropeptides are responsible for regulating a variety of functions, including development, metabolism, water and ion homeostasis, and as neuromodulators in circuits of the central nervous system. Numerous neuropeptides have been identified and characterized. However, both discovery and functional characterization of neuropeptides across the massive Class Insecta has been sporadic. To leverage advances in post-genomic technologies for this rapidly growing field, insect neuroendocrinology requires a consolidated, comprehensive and standardised resource for managing neuropeptide information. The Database for Insect Neuropeptide Research (DINeR) is a web-based database-application used for search and retrieval of neuropeptide information of various insect species detailing their isoform sequences, physiological functionality and images of their receptor-binding sites, in an intuitive, accessible and user-friendly format. The curated data includes representatives of 50 well described neuropeptide families from over 400 different insect species. Approximately 4700 FASTA formatted, neuropeptide isoform amino acid sequences and over 200 records of physiological functionality have been recorded based on published literature. Also available are images of neuropeptide receptor locations. In addition, the data include comprehensive summaries for each neuropeptide family, including their function, location, known functionality, as well as cladograms, sequence alignments and logos covering most insect orders. Moreover, we have adopted a standardized nomenclature to address inconsistent classification of neuropeptides. As part of the H2020 nEUROSTRESSPEP project, the data will be actively maintained and curated, ensuring a comprehensive and standardised resource for the scientific community. DINeR is publicly available at the project website: http://www.neurostresspep.eu/diner/.
      Graphical abstract image

      PubDate: 2017-05-12T13:24:41Z
      DOI: 10.1016/j.ibmb.2017.05.001
       
  • Identification and functional analysis of outer kinetochore genes in the
           holocentric insect Bombyx mori
    • Authors: Hiroaki Mon; Jae Man Lee; Masanao Sato; Takahiro Kusakabe
      Abstract: Publication date: Available online 1 May 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Hiroaki Mon, Jae Man Lee, Masanao Sato, Takahiro Kusakabe
      The kinetochore creates chromosomal attachment sites for microtubules. The kinetochore-microtubule interface plays an important role in ensuring accurate transmission of genetic information to daughter cells. Bombyx mori is known to possess holocentric chromosomes, where spindle microtubules attach along the entire length of the chromosome. Recent evidence suggests that CENP-A and CENP-C, which are essential for centromere structure and function in other species, have lost in holocentric insects, implying that B. mori is able to build its kinetochore regardless of the lack of CENP-A and CENP-C. Here we report the identification of three outer kinetochore genes in the silkworm B. mori by using bioinformatics and RNA interference-based screening. While the homologs of Ndc80 and Mis12 have strong similarity with those of other organisms, the five encoded proteins (BmNuf2, BmSpc24, BmSpc25, BmDsn1 and BmNnf1) are highly diverged from their counterparts in other species. Microscopic studies show that the outer kinetochore protein is distributed along the entire length of the chromosomes, which is a key feature of holocentric chromosomes. We also demonstrate that BmDsn1 forms a heterotrimeric complex with BmMis12 and BmNnf1, which acts as a receptor of the Ndc80 complex. In addition, our study suggests that a small-scale RNAi-based candidate screening is a useful approach to identify genes which may be highly divergent among different species.
      Graphical abstract image

      PubDate: 2017-05-02T12:50:08Z
      DOI: 10.1016/j.ibmb.2017.04.005
       
  • Arabidopsis glucosinolates trigger a contrasting transcriptomic response
           in a generalist and a specialist herbivore.
    • Authors: Fabian Schweizer; Hanna Heidel-Fischer; Heiko Vogel; Philippe Reymond
      Abstract: Publication date: Available online 26 April 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Fabian Schweizer, Hanna Heidel-Fischer, Heiko Vogel, Philippe Reymond
      Phytophagous insects have to deal with toxic defense compounds from their host plants. Although it is known that insects have evolved genes and mechanisms to detoxify plant allochemicals, how specialist and generalist precisely respond to specific secondary metabolites at the molecular level is less understood. Here we studied the larval performance and transcriptome of the generalist moth Heliothis virescens and the specialist butterfly Pieris brassicae feeding on Arabidopsis thaliana genotypes with different glucosinolate (GS) levels. H. virescens larvae gained significantly more weight on the GS-deficient mutant quadGS compared to wild-type (Col-0) plants. On the contrary, P. brassicae was unaffected by the presence of GS and performed equally well on both genotypes. Strikingly, there was a considerable differential gene expression in H. virescens larvae feeding on Col-0 compared to quadGS. In contrast, compared to H. virescens, P. brassicae displayed a much-reduced transcriptional activation when fed on both plant genotypes. Transcripts coding for putative detoxification enzymes were significantly upregulated in H. virescens, along with digestive enzymes and transposable elements. These data provide an unprecedented view on transcriptional changes that are specifically activated by GS and illustrate differential molecular responses that are linked to adaptation to diet in lepidopteran herbivores.
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      PubDate: 2017-05-02T12:50:08Z
      DOI: 10.1016/j.ibmb.2017.04.004
       
  • Leptinotarsa cap ‘n’ collar isoform C/Kelch-like ECH associated
           protein 1 signaling is critical for the regulation of ecdysteroidogenesis
           in the larvae
    • Authors: Qiang-Kun Sun; Qing-Wei Meng; Qing-Yu Xu; Pan Deng; Wen-Chao Guo; Guo-Qing Li
      Abstract: Publication date: Available online 10 April 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Qiang-Kun Sun, Qing-Wei Meng, Qing-Yu Xu, Pan Deng, Wen-Chao Guo, Guo-Qing Li
      Drosophila cap ‘n’ collar isoform C (CncC) and Kelch-like ECH associated protein 1 (Keap1) regulate metamorphosis by transcriptional control of a subset of genes involved in ecdysteroidogenesis, 20-hydroxyecdysone (20E) signaling, and juvenile hormone (JH) degradation. In the present paper, we found that prothoracicotropic hormone signal was required for the activation of LdCncC and LdKeap1 in Leptinotarsa decemlineata. Moreover, RNA interference of LdCncC or LdKeap1 in the fourth-instar larvae delayed development. As a result, the treated larvae obtained heavier larval and pupal fresh weights and had larger body sizes than the controls. Furthermore, knockdown of LdCncC or LdKeap1 significantly reduced the mRNA levels of four ecdysone biosynthetic genes (Ldspo, Ldphm, Lddib and Ldsad), lowered 20E titer and decreased the transcript levels of five 20E response genes (LdEcR, LdUSP, LdE75, LdHR3 and LdFTZ-F1). However, the expression of two JH epoxide hydrolase genes and JH contents were not affected in the LdCncC and LdKeap1 RNAi larvae. Dietary supplementation with 20E shortened the developmental period to normal length, rescued the larval and pupal body mass rises, and recovered or even overcompensated the expression levels of the five 20E response genes in either LdCncC or LdKeap1 RNAi hypomorphs. Therefore, LdCncC/LdKeap1 signaling regulates several ecdysteroidogenesis genes, and consequently 20E pulse, to modulate the onset of metamorphosis in L. decemlineata.
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      PubDate: 2017-04-11T09:51:24Z
      DOI: 10.1016/j.ibmb.2017.04.001
       
  • Manduca sexta hemolymph protease-1, activated by an unconventional
           non-proteolytic mechanism, mediates immune responses
    • Authors: Yan He; Yang Wang; Fan Yang; Haobo Jiang
      Abstract: Publication date: Available online 31 March 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yan He, Yang Wang, Fan Yang, Haobo Jiang
      Tissue damage or pathogen invasion triggers the auto-proteolysis of an initiating serine protease (SP), rapidly leading to sequential cleavage activation of other cascade members to set off innate immune responses in insects. Recently, we presented evidence that Manduca sexta hemolymph protease-1 zymogen (proHP1) is a member of the SP system in this species, and may activate proHP6. HP6 stimulates melanization and induces antimicrobial peptide synthesis. Here we report that proHP1 adopts an active conformation (*) to carry out its function, without a requirement for proteolytic activation. Affinity chromatography using HP1 antibodies isolated from induced hemolymph the 48 kDa proHP1 and also a 90 kDa band (detected by SDS-PAGE under reducing conditions) containing proHP1 and several serpins, as revealed by mass spectrometric analysis. Identification of tryptic peptides from these 90 kDa complexes included peptides from the amino-terminal regulatory part of proHP1, indicating that proHP1* was not cleaved, and that it had formed a complex with the serpins. As suicide inhibitors, serpins form SDS-stable, acyl-complexes when they are attacked by active proteases, indicating that proHP1* was catalytically active. Detection of M. sexta serpin-1, 4, 9, 13 and smaller amounts of serpin-3, 5, 6 in the complexes suggests that it is regulated by multiple serpins in hemolymph. We produced site-directed mutants of proHP1b for cleavage by bovine blood coagulation factor Xa at the designed proteolytic activation site, to generate a form of proHP1b that could be activated by Factor Xa. However, proHP1b cut by Factor Xa failed to activate proHP6 and, via HP6, proHP8 or proPAP1. This negative result is consistent with the suggestion that proHP1* is a physiological mediator of immune responses. Further research is needed to investigate the conformational change that results in conversion of proHP1 to active proHP1*.
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      PubDate: 2017-04-04T09:49:20Z
      DOI: 10.1016/j.ibmb.2017.03.008
       
  • Design of larval chemical attractants based on odorant response spectra of
           olfactory receptors in the cotton bollworm
    • Authors: Chang Di; Chao Ning; Ling-Qiao Huang; Chen-Zhu Wang
      Abstract: Publication date: Available online 31 March 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Chang Di, Chao Ning, Ling-Qiao Huang, Chen-Zhu Wang
      Lepidopteran caterpillars rely on olfaction and gustation to discriminate among food sources. Compared to the larval gustation, the larval olfaction has been poorly investigated. To uncover the molecular basis of olfaction in Helicoverpa armigera larvae, we identified 17 Or genes in larval antennae and maxillae using transcriptome sequencing, and functionally identified the response spectra of seven Ors to ecologically relevant odorants. Innate behavioural responses of larvae to active odorants were evaluated in chemotaxis assays. Several odorant blends were formulated based on the Ors tuning spectra and caterpillar chemotaxis. A four-component blend strongly attracted H. armigera larvae, and cis-jasmone and 1-pentanol were identified as essential components. Localization analyses showed that the two Ors detecting these components (Or41 and Or52) were expressed in the same sensory neurons. This is the first evidence that Ors in a polyphagous caterpillar respond to odorants in a combinatorial manner. The design of attractants to target specific olfactory pathways may promote the development of new baits for pest management.
      Graphical abstract image

      PubDate: 2017-04-04T09:49:20Z
      DOI: 10.1016/j.ibmb.2017.03.007
       
  • Afidopyropen: New and potent modulator of insect transient receptor
           potential channels
    • Authors: Ramani Kandasamy; Damian London; Lynn Stam; Wolfgang von Deyn; Xilong Zhao; Vincent L. Salgado; Alexandre Nesterov
      Abstract: Publication date: Available online 24 March 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Ramani Kandasamy, Damian London, Lynn Stam, Wolfgang von Deyn, Xilong Zhao, Vincent L. Salgado, Alexandre Nesterov
      The commercial insecticides pymetrozine and pyrifluquinazon control plant-sucking pests by disturbing their coordination and ability to feed. We have previously shown that these compounds act by overstimulating and eventually silencing vanilloid-type transient receptor potential (TRPV) channels, which consist of two proteins, Nanchung and Inactive, which are co-expressed exclusively in insect chordotonal stretch receptor neurons. Here we show that a new insecticidal compound, afidopyropen, modulates chordotonal organs of American grasshoppers (Schistocerca americana) in the same fashion. Afidopyropen stimulated heterologously expressed TRPV channels from two different insect species, fruit fly (Drosophila melanogaster) and pea aphid (Acyrthosiphon pisum), but not the mammalian TRPV channel TRPV4. Activation of the insect TRPVs required simultaneous expression of both Nanchung and Inactive proteins. Tritium-labeled afidopyropen bound fruit fly TRPVs with higher affinity than pymetrozine and competed with pymetrozine for binding. Nanchung protein formed the main binding interface for afidopyropen, whereas co-expression of Inactive dramatically increased binding affinity. Another modulator of chordotonal organs, flonicamid, did not activate insect TRPV channels, nor did it compete with afidopyropen for binding, indicating that it has a different target protein. These results define afidopyropen as a new, potent and specific modulator of insect TRPV channels, and provide insight into the unique binding mode for these compounds.
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      PubDate: 2017-03-28T09:07:02Z
      DOI: 10.1016/j.ibmb.2017.03.005
       
  • The role of miR-2∼13∼71 cluster in resistance to deltamethrin
           in Culex pipiens pallens
    • Authors: Qin Guo; Yun Huang; Feifei Zou; Bingqian Liu; Mengmeng Tian; Wenyun Ye; Juxin Guo; Xueli Sun; Dan Zhou; Yan Sun; Lei Ma; Bo Shen; Changliang Zhu
      Abstract: Publication date: Available online 23 March 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Qin Guo, Yun Huang, Feifei Zou, Bingqian Liu, Mengmeng Tian, Wenyun Ye, Juxin Guo, Xueli Sun, Dan Zhou, Yan Sun, Lei Ma, Bo Shen, Changliang Zhu
      Excessive and continuous application of deltamethrin has resulted in the development of deltamethrin resistance among mosquitoes, which becomes a major obstacle for mosquito control. In a previous study, differentially expressed miRNAs between deltamethrin-susceptible (DS) strain and deltamethrin-resistant (DR) strain using illumina sequencing in Culex pipiens pallens were identified. In this study, we applied RNAi and the Centers for Disease Control and Prevention (CDC) bottle bioassay to investigate the relationship between miR-2∼13∼71 cluster (miR-2, miR-13 and miR-71) and deltamethrin resistance. We used quantitative real-time PCR (qRT-PCR) to measure expression levels of miR-2∼13∼71 clusters. MiR-2∼13∼71 cluster was down regulated in adult female mosquitoes from the DR strain and played important roles in deltamethrin resistance through regulating target genes, CYP9J35 and CYP325BG3. Knocking down CYP9J35 and CYP325BG3 resulted in decreased mortality of DR mosquitoes. This study provides the first evidence that miRNA clusters are associated with deltamethrin resistance in mosquitoes. Moreover, we investigated the regulatory networks formed between miR-2∼13∼71 cluster and its target genes, which provide a better understanding of the mechanism involved in deltamethrin resistance.
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      PubDate: 2017-03-28T09:07:02Z
      DOI: 10.1016/j.ibmb.2017.03.006
       
  • Changes in microRNA abundance may regulate diapause in the flesh fly,
           Sarcophaga bullata
    • Authors: Julie A. Reynolds; Justin T. Peyton; David L. Denlinger
      Abstract: Publication date: Available online 12 March 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Julie A. Reynolds, Justin T. Peyton, David L. Denlinger
      Diapause, an alternative developmental pathway characterized by changes in developmental timing and metabolism, is coordinated by molecular mechanisms that are not completely understood. MicroRNA (miRNA) mediated gene silencing is emerging as a key component of animal development and may have a significant role in initiating, maintaining, and terminating insect diapause. In the present study, we test this possibility by using high-throughput sequencing and qRT-PCR to discover diapause-related shifts in miRNA abundance in the flesh fly, Sarcophaga bullata. We identified ten evolutionarily conserved miRNAs that were differentially expressed in diapausing pupae compared to their nondiapausing counterparts. miR-289-5p and miR-1-3p were overexpressed in diapausing pupae and may be responsible for silencing expression of candidate genes during diapause. miR-9c-5p, miR-13b-3p, miR-31a-5p, miR-92b-3p, miR-275-3p, miR-276a-3p, miR-277-3p, and miR-305-5p were underexpressed in diapausing pupae and may contribute to increased expression of heat shock proteins and other factors necessary for the enhanced environmental stress-response that is a feature of diapause. In S. bullata, a maternal effect blocks the programming of diapause in progeny of females that have experienced pupal diapause, and in this study we report that several miRNAs, including MiR-263a-5p, miR-100-5p, miR-125-5p, and let-7-5p were significantly overexpressed in such nondiapausing flies and may prevent entry into diapause. Together these miRNAs appear to be integral to the molecular processes that mediate entry into diapause.
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      PubDate: 2017-03-13T01:54:02Z
      DOI: 10.1016/j.ibmb.2017.03.002
       
  • Identification, expression pattern, and feature analysis of cuticular
           protein genes in the pine moth Dendrolimus punctatus (Lepidoptera:
           Lasiocampidae)
    • Authors: Cong-Hui Yang; Peng-Cheng Yang; Su-Fang Zhang; Zhi-Yong Shi; Le Kang; Ai-Bing Zhang
      Abstract: Publication date: Available online 9 March 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Cong-Hui Yang, Peng-Cheng Yang, Su-Fang Zhang, Zhi-Yong Shi, Le Kang, Ai-Bing Zhang
      Cuticular proteins (CPs) are vital components of the insects’ cuticle that support movement and protect insect from adverse environmental conditions. The CPs exist in a large number and diversiform structures, thus, the accurate annotation is the first step to interpreting their roles in insect growth. The rapid development of sequencing technology has simplified the access to the information on protein sequences, especially for non-model species. Dendrolimus punctatus is a Lepidopteran defoliator, and its periodic outbreaks cause severe damage to the coniferous forests. The transcriptome of D. punctatus integrating the whole developmental periods are available for the potential investigation of CPs. In this study, we identified 216 CPs from D. punctatus, including 147 from CPR family, 4 from TWDL family, 3 from CPF/CPFL families, 22 from CPAP families, 8 low complexity proteins, 1 CPCPC and 31 from other CP families. The putative CPs were compared with homologs in other species such as Bombyx mori, Manduca sexta and Drosophila melanogaster. We further identified five co-orthologous groups have highly similar sequences of CRPs in nine lepidopteran species, which exclusively presented in RR-2 subfamily rather than RR-1. We inferred that in Lepidoptera the difference in RR-2 numbers was maintained by homologs in co-orthologous groups, coincided with observation in Drosophila and Anopheles that gene cluster was the model and source for the expansion of RR-2 genes. In combination with the variation of members in each CP family among different species, these results indicated the evolution of CPs was highly correlated to the adaptation of insect to environment. Furthermore, we compared the amino acid composition of the different types CPRs, and examined the expression patterns of CP genes in various developmental stages. The comprehensive overview of CPs from our study provides an insight into their evolution and the association between them and insect development.
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      PubDate: 2017-03-13T01:54:02Z
      DOI: 10.1016/j.ibmb.2017.03.003
       
  • Rudimentary expression of RYamide in Drosophila melanogaster relative to
           other Drosophila species points to a functional decline of this
           neuropeptide gene
    • Authors: Jan A. Veenstra; Hela Khammassi
      Abstract: Publication date: Available online 7 March 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Jan A. Veenstra, Hela Khammassi
      RYamides are arthropod neuropeptides with unknown function. In 2011 two RYamides were isolated from D. melanogaster as the ligands for the G-protein coupled receptor CG5811. The D. melanogaster gene encoding these neuropeptides is highly unusual, as there are four RYamide encoding exons in the current genome assembly, but an exon encoding a signal peptide is absent. Comparing the D. melanogaster gene structure with those from other species, including D. virilis, suggests that the gene is degenerating. RNAseq data from 1634 short sequence read archives at NCBI containing more than 34 billion spots yielded numerous individual spots that correspond to the RYamide encoding exons, of which a large number include the intron-exon boundary at the start of this exon. Although 72 different sequences have been spliced onto this RYamide encoding exon, none codes for the signal peptide of this gene. Thus, the RNAseq data for this gene reveal only noise and no signal. The very small quantities of peptide recovered during isolation and the absence of credible RNAseq data, indicates that the gene is very little expressed, while the RYamide gene structure in D. melanogaster suggests that it might be evolving into a pseudogene. Yet, the identification of the peptides it encodes clearly shows it is still functional. Using region specific antisera, we could localize numerous neurons and enteroendocrine cells in D. willistoni, D. virilis and D. pseudoobscura, but only two adult abdominal neurons in D. melanogaster. Those two neurons project to and innervate the rectal papillae, suggesting that RYamides may be involved in the regulation of water homeostasis.
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      PubDate: 2017-03-09T01:37:15Z
      DOI: 10.1016/j.ibmb.2017.03.001
       
  • Characterisation, analysis of expression and localisation of circadian
           clock genes from the perspective of photoperiodism in the aphid
           Acyrthosiphon pisum
    • Authors: Miquel Barberà; Jorge Mariano Collantes-Alegre; David Martínez-Torres
      Abstract: Publication date: Available online 22 February 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Miquel Barberà, Jorge Mariano Collantes-Alegre, David Martínez-Torres
      Aphids are typical photoperiodic insects that switch from viviparous parthenogenetic reproduction typical of long day seasons to oviparous sexual reproduction triggered by the shortening of photoperiod in autumn yielding an overwintering egg in which an embryonic diapause takes place. While the involvement of the circadian clock genes in photoperiodism in mammals is well established, there is still some controversy on their participation in insects. The availability of the genome of the pea aphid Acyrthosiphon pisum places this species as an excellent model to investigate the involvement of the circadian system in the aphid seasonal response. In the present report, we have advanced in the characterization of the circadian clock genes and showed that these genes display extensive alternative splicing. Moreover, the expression of circadian clock genes, analysed at different moments of the day, showed a robust cycling of central clock genes period and timeless. Furthermore, the rhythmic expression of these genes was shown to be rapidly dampened under DD (continuous darkness conditions), thus supporting the model of a seasonal response based on a heavily dampened circadian oscillator. Additionally, increased expression of some of the circadian clock genes under short-day conditions suggest their involvement in the induction of the aphid seasonal response. Finally, in situ localisation of transcripts of genes period and timeless in the aphid brain revealed the site of clock neurons for the first time in aphids. Two groups of clock cells were identified: the Dorsal Neurons (DN) and the Lateral Neurons (LN), both in the protocerebrum.
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      PubDate: 2017-02-24T04:13:05Z
      DOI: 10.1016/j.ibmb.2017.02.006
       
  • Urate Oxidase produced by Lucilia sericata medical maggots is localized in
           Malpighian tubes and facilitates allantoin production
    • Authors: Andre Baumann; Marisa Skaljac; Rüdiger Lehmann; Andreas Vilcinskas; Zdenӗk Franta
      Abstract: Publication date: Available online 22 February 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Andre Baumann, Marisa Skaljac, Rüdiger Lehmann, Andreas Vilcinskas, Zdenӗk Franta
      Lucilia sericata maggots are the only species currently approved for maggot debridement therapy (MDT), an alternative treatment for chronic and recalcitrant wounds. Maggots promote wound debridement, disinfection and healing by producing a complex mixture of proteins, peptides and low-molecular-weight compounds in their secretions and excretions, but the individual components are not well characterized at the molecular level. Here we investigated the purine catabolism pathway in L. sericata, focusing on the production of allantoin by Urate Oxidase (UO), which is thought to promote wound healing. We produced recombinant L. sericata UO in Escherichia coli, and characterized the properties of the pure enzyme in terms of the optimum pH (7–10) and temperature (20–25 °C), its stability, sensitivity to inhibition and ion dependency. We used quantitative RT-PCR and RNA in situ hybridization to monitor the expression of the UO gene, and we used a guinea pig anti-UO antibody to detect the native enzyme by western blot and by florescence immunohistochemistry in larval tissues. We found that L. sericata UO is exclusively present in the larval excretion organ (the Malpighian tubes) and is freely available in the cytoplasm rather than restricted to a specific subcellular compartment. Allantoin is a final product of L. sericata purine catabolism. It is produced by UO in the Malpighian tubes to remove uric acid from the hemolymph and is consequently excreted via the hindgut. Our findings confirm the hypothesis that both actively secreted molecules and excretion products contribute to the beneficial effects of MDT.
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      PubDate: 2017-02-24T04:13:05Z
      DOI: 10.1016/j.ibmb.2017.02.007
       
  • Diversity and functions of protein glycosylation in insects
    • Authors: Tomasz Walski; Kristof De Schutter; Els J.M. Van Damme; Guy Smagghe
      Abstract: Publication date: Available online 14 February 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Tomasz Walski, Kristof De Schutter, Els J.M. Van Damme, Guy Smagghe
      The majority of proteins is modified with carbohydrate structures. This modification, called glycosylation, was shown to be crucial for protein folding, stability and subcellular location, as well as protein-protein interactions, recognition and signaling. Protein glycosylation is involved in multiple physiological processes, including embryonic development, growth, circadian rhythms, cell attachment as well as maintenance of organ structure, immunity and fertility. Although the general principles of glycosylation are similar among eukaryotic organisms, insects synthesize a distinct repertoire of glycan structures compared to plants and vertebrates. Consequently, a number of unique insect glycans mediate functions specific to this class of invertebrates. For instance, the core α1,3-fucosylation of N-glycans is absent in vertebrates, while in insects this modification is crucial for the development of wings and the nervous system. At present, most of the data on insect glycobiology comes from research in Drosophila. Yet, progressively more information on the glycan structures and the importance of glycosylation in other insects like beetles, caterpillars, aphids and bees is becoming available. This review gives a summary of the current knowledge and recent progress related to glycan diversity and function(s) of protein glycosylation in insects. We focus on N- and O-glycosylation, their synthesis, physiological role(s), as well as the molecular and biochemical basis of these processes.
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      PubDate: 2017-02-17T03:04:45Z
      DOI: 10.1016/j.ibmb.2017.02.005
       
  • An integrated CRISPR Bombyx mori genome editing system with improved
           efficiency and expanded target sites
    • Authors: Sanyuan Ma; Yue Liu; Yuanyuan Liu; Jiasong Chang; Tong Zhang; Xiaogang Wang; Run Shi; Wei Lu; Xiaojuan Xia; Ping Zhao; Qingyou Xia
      Abstract: Publication date: Available online 9 February 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Sanyuan Ma, Yue Liu, Yuanyuan Liu, Jiasong Chang, Tong Zhang, Xiaogang Wang, Run Shi, Wei Lu, Xiaojuan Xia, Ping Zhao, Qingyou Xia
      Genome editing enabled unprecedented new opportunities for targeted genomic engineering of a wide variety of organisms ranging from microbes, plants, animals and even human embryos. The serial establishing and rapid applications of genome editing tools significantly accelerated Bombyx mori (B. mori) research during the past years. However, the only CRISPR system in B. mori was the commonly used SpCas9, which only recognize target sites containing NGG PAM sequence. In the present study, we first improve the efficiency of our previous established SpCas9 system by 3.5 folds. The improved high efficiency was also observed at several loci in both BmNs cells and B. mori embryos. Then to expand the target sites, we showed that two newly discovered CRISPR system, SaCas9 and AsCpf1, could also induce highly efficient site-specific genome editing in BmNs cells, and constructed an integrated CRISPR system. Genome-wide analysis of targetable sites was further conducted and showed that the integrated system cover 69,144,399 sites in B. mori genome, and one site could be found in every 6.5 bp. The efficiency and resolution of this CRISPR platform will probably accelerate both fundamental researches and applicable studies in B. mori, and perhaps other insects.
      Graphical abstract image

      PubDate: 2017-02-10T23:31:08Z
      DOI: 10.1016/j.ibmb.2017.02.003
       
  • Transcription factor cap n collar C regulates multiple cytochrome P450
           genes conferring adaptation to potato plant allelochemicals and resistance
           to imidacloprid in Leptinotarsa decemlineata (Say)
    • Authors: Megha Kalsi; Subba Reddy Palli
      Abstract: Publication date: Available online 9 February 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Megha Kalsi, Subba Reddy Palli
      Colorado potato beetle (CPB), Leptinotarsa decemlineata is a notorious pest of potato. Co-evolution with Solanaceae plants containing high levels of toxins (glycoalkaloids) helped this insect to develop an efficient detoxification system and resist almost every chemical insecticide introduced for its control. Even though the cross-resistance between plant allelochemicals and insecticides is well acknowledged, the underlying molecular mechanisms are not understood. Here, we investigated the molecular mechanisms involved in detoxification of potato plant allelochemicals and imidacloprid resistance in the field-collected CPB. Our results showed that the imidacloprid-resistant beetles employ metabolic detoxification of both potato plant allelochemicals and imidacloprid by upregulation of common cytochrome P450 genes. RNAi aided knockdown identified four cytochromes P450 genes (CYP6BJa/b, CYP6BJ1v1, CYP9Z25, and CYP9Z29) that are required for defense against both natural and synthetic chemicals. These P450 genes are regulated by the xenobiotic transcription factors Cap n Collar C, CncC and muscle aponeurosis fibromatosis, Maf. Studies on the CYP9Z25 promoter using the luciferase reporter assay identified two binding sites (i.e. GCAGAAT and GTACTGA) for CncC and Maf. Overall, these data showed that CPB employs the metabolic resistance mediated through xenobiotic transcription factors CncC and Maf to regulate multiple P450 genes and detoxify both imidacloprid and potato plant allelochemicals.
      Graphical abstract image

      PubDate: 2017-02-10T23:31:08Z
      DOI: 10.1016/j.ibmb.2017.02.002
       
  • Expression map of a complete set of gustatory receptor genes in
           chemosensory organs of Bombyx mori
    • Authors: Huizhen Guo; Tingcai Cheng; Zhiwei Chen; Liang Jiang; Youbing Guo; Jianqiu Liu; Shenglong Li; Kiyoko Taniai; Kiyoshi Asaoka; Keiko Kadono-Okuda; Kallare P. Arunkumar; Jiaqi Wu; Hirohisa Kishino; Huijie Zhang; Rakesh K. Seth; Karumathil P. Gopinathan; Nicolas Montagné; Emmanuelle Jacquin-Joly; Marian R. Goldsmith; Qingyou Xia; Kazuei Mita
      Abstract: Publication date: Available online 7 February 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Huizhen Guo, Tingcai Cheng, Zhiwei Chen, Liang Jiang, Youbing Guo, Jianqiu Liu, Shenglong Li, Kiyoko Taniai, Kiyoshi Asaoka, Keiko Kadono-Okuda, Kallare P. Arunkumar, Jiaqi Wu, Hirohisa Kishino, Huijie Zhang, Rakesh K. Seth, Karumathil P. Gopinathan, Nicolas Montagné, Emmanuelle Jacquin-Joly, Marian R. Goldsmith, Qingyou Xia, Kazuei Mita
      Most lepidopteran species are herbivores, and interaction with host plants affects their gene expression and behavior as well as their genome evolution. Gustatory receptors (Grs) are expected to mediate host plant selection, feeding, oviposition and courtship behavior. However, due to their high diversity, sequence divergence and extremely low level of expression it has been difficult to identify precisely a complete set of Grs in Lepidoptera. By manual annotation and BAC sequencing, we improved annotation of 43 gene sequences compared with previously reported Grs in the most studied lepidopteran model, the silkworm, Bombyx mori, and identified 7 new tandem copies of BmGr30 on chromosome 7, bringing the total number of BmGrs to 76. Among these, we mapped 68 genes to chromosomes in a newly constructed chromosome distribution map and 8 genes to scaffolds; we also found new evidence for large clusters of BmGrs, especially from the bitter receptor family. RNA-seq analysis of diverse BmGr expression patterns in chemosensory organs of larvae and adults enabled us to draw a precise organ specific map of BmGr expression. Interestingly, most of the clustered genes were expressed in the same tissues and more than half of the genes were expressed in larval maxillae, larval thoracic legs and adult legs. For example, BmGr63 showed high expression levels in all organs in both larval and adult stages. By contrast, some genes showed expression limited to specific developmental stages or organs and tissues. BmGr19 was highly expressed in larval chemosensory organs (especially antennae and thoracic legs), the single exon genes BmGr53 and BmGr67, were expressed exclusively in larval tissues, the BmGr27–BmGr31 gene cluster on chr7 displayed a high expression level limited to adult legs and the candidate CO2 receptor BmGr2 was highly expressed in adult antennae, where few other Grs were expressed. Transcriptional analysis of the Grs in B. mori provides a valuable new reference for finding genes involved in plant-insect interactions in Lepidoptera and establishing correlations between these genes and vital insect behaviors like host plant selection and courtship for mating.
      Graphical abstract image

      PubDate: 2017-02-10T23:31:08Z
      DOI: 10.1016/j.ibmb.2017.02.001
       
  • Chemoreception to aggregation pheromones in the common bed bug, Cimex
           lectularius
    • Authors: Feng Liu; Caixing Xiong; Nannan Liu
      Abstract: Publication date: Available online 3 February 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Feng Liu, Caixing Xiong, Nannan Liu
      The common bed bug, Cimex lectularius, is an obligate blood-feeding insect that is resurgent worldwide, posing a threat to human beings through its biting nuisance and disease transmission. Bed bug aggregation pheromone is considered a very promising attractant for use in the monitoring and management of bed bugs, but as yet little is known regarding the sensory physiology of bed bugs related to this pheromone. This study examined how the individual components of aggregation pheromone are perceived by the olfactory receptor neurons (ORNs) housed in different types of olfactory sensilla in bed bugs and the molecular basis for the ORNs' responses to the aggregation pheromone. We found that the ORNs in the D olfactory sensilla played a predominant role in detecting all the components of aggregation pheromone except for histamine, which was only recognized by the C sensilla. Bed bugs’ E sensilla, which include four functionally distinct groups, showed only a very weak but variant sensitivity (both excitatory and inhibitory) to the components of aggregation pheromone. Functional tests of 15 odorant receptors (ORs) in response to the components of aggregation pheromone revealed that most of these components were encoded by multiple ORs with various tuning properties. This study provides a comprehensive understanding of how bed bug aggregation pheromone is perceived and recognized in the peripheral olfactory system and will contribute useful information to support the development of synthetic attractants for bed bug monitoring and control.
      Graphical abstract image

      PubDate: 2017-02-04T23:04:10Z
      DOI: 10.1016/j.ibmb.2017.01.012
       
  • Proteomic and metabolomic analysis reveals rapid and extensive nicotine
           detoxification ability in honey bee larvae
    • Authors: Esther E. du Rand; Hannelie Human; Salome Smit; Mervyn Beukes; Zeno Apostolides; Susan W. Nicolson; Christian W.W. Pirk
      Abstract: Publication date: Available online 1 February 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Esther E. du Rand, Hannelie Human, Salome Smit, Mervyn Beukes, Zeno Apostolides, Susan W. Nicolson, Christian W.W. Pirk
      Despite potential links between pesticides and bee declines, toxicology information on honey bee larvae (Apis mellifera) is scarce and detoxification mechanisms in this development stage are virtually unknown. Larvae are exposed to natural and synthetic toxins present in pollen and nectar through consumption of brood food. Due to the characteristic intensive brood care displayed by honey bees, which includes progressive feeding throughout larval development, it is generally assumed that larvae rely on adults to detoxify for them and exhibit a diminished detoxification ability. We found the opposite. We examined the proteomic and metabolomic responses of in vitro reared larvae fed nicotine (an alkaloid found in nectar and pollen) to understand how larvae cope on a metabolic level with dietary toxins. Larvae were able to effectively detoxify nicotine through an inducible detoxification mechanism. A coordinated stress response complemented the detoxification processes, and we detected significant enrichment of proteins functioning in energy and carbohydrate metabolism, as well as in development pathways, suggesting that nicotine may promote larval growth. Further exploration of the metabolic fate of nicotine using targeted mass spectrometry analysis demonstrated that, as in adult bees, formation of 4-hydroxy-4-(3-pyridyl) butanoic acid, the result of 2′C-oxidation of nicotine, is quantitatively the most significant pathway of nicotine metabolism. We provide conclusive evidence that larvae are capable of effectively catabolising a dietary toxin, suggesting that increased larval sensitivity to specific toxins is not due to diminished detoxification abilities. These findings broaden the current understanding of detoxification biochemistry at different organizational levels in the colony, bringing us closer to understanding the capacity of the colony as a superorganism to tolerate and resist toxic compounds, including pesticides, in the environment.
      Graphical abstract image

      PubDate: 2017-02-04T23:04:10Z
      DOI: 10.1016/j.ibmb.2017.01.011
       
  • An isoform of Taiman that contains a PRD-repeat motif is indispensable for
           transducing the vitellogenic juvenile hormone signal in Locusta migratoria
           
    • Authors: Zhiming Wang; Libin Yang; Jiasheng Song; Le Kang; Shutang Zhou
      Abstract: Publication date: Available online 27 January 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Zhiming Wang, Libin Yang, Jiasheng Song, Le Kang, Shutang Zhou
      Taiman (Tai) has been recently identified as the dimerizing partner of juvenile hormone (JH) receptor, Methoprene-tolerant (Met). However, the role of Tai isoforms in transducing vitellogenic signal of JH has not been determined. In this study, we show that the migratory locust Locusta migratoria has two Tai isoforms, which differ in an INDEL-1 domain with the PRD-repeat motif rich in histidine and proline at the C-terminus. Tai-A with the INDEL-1 is expressed at levels about 50-fold higher than Tai-B without the INDEL-1 in the fat body of vitellogenic adult females. Knockdown of Tai-A but not Tai-B results in a substantial reduction of vitellogenin expression in the fat body accompanied by the arrest of ovarian development and oocyte maturation, similar to that caused by depletion of both Tai isoforms. Either Tai-A or Tai-B combined with Met can induce target gene transcription in response to JH, but Tai-A appears to mediate a significantly higher transactivation. Our data suggest that the INDEL-1 domain plays a critical role in Tai function during reproduction as Tai-A appears be more active than Tai-B in transducing the vitellogenic JH signal in L. migratoria.
      Graphical abstract image

      PubDate: 2017-01-29T22:03:30Z
      DOI: 10.1016/j.ibmb.2017.01.009
       
  • Co-option of the sphingolipid metabolism for the production of nitroalkene
           defensive chemicals in termite soldiers
    • Authors: Anna Jirošová; Andrej Jančařík; Riya C. Menezes; Olga Bazalová; Klára Dolejšová; Heiko Vogel; Pavel Jedlička; Aleš Buček; Jana Brabcová; Pavel Majer; Robert Hanus; Aleš Svatoš
      Abstract: Publication date: Available online 23 January 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Anna Jirošová, Andrej Jančařík, Riya C. Menezes, Olga Bazalová, Klára Dolejšová, Heiko Vogel, Pavel Jedlička, Aleš Buček, Jana Brabcová, Pavel Majer, Robert Hanus, Aleš Svatoš
      The aliphatic nitroalkene (E)-nitropentadec-1-ene (NPD), reported in early seventies in soldiers of the termite genus Prorhinotermes, was the first documented nitro compound produced by insects. Yet, its biosynthetic origin has long remained unknown. Here, we investigated in detail the biosynthesis of NPD in P. simplex soldiers. First, we track the dynamics in major metabolic pathways during soldier ontogeny, with emphasis on likely NPD precursors and intermediates. Second, we propose a hypothesis of NPD formation and verify its individual steps using in vivo incubations of putative precursors and intermediates. Third, we use a de novo assembled RNA-Seq profiles of workers and soldiers to identify putative enzymes underlying NPD formation. And fourth, we describe the caste- and age-specific expression dynamics of candidate initial genes of the proposed biosynthetic pathway. Our observations provide a strong support to the following biosynthetic scenario of NPD formation, representing an analogy of the sphingolipid pathway starting with the condensation of tetradecanoic acid with l-serine and leading to the formation of a C16 sphinganine. The C16 sphinganine is then oxidized at the terminal carbon to give rise to 2-amino-3-hydroxyhexadecanoic acid, further oxidized to 2-amino-3-oxohexadecanoic acid. Subsequent decarboxylation yields 1-aminopentadecan-2-one, which then proceeds through six-electron oxidation of the amino moiety to give rise to a 1-nitropentadecan-2-one. Keto group reduction and hydroxyl moiety elimination leads to NPD. The proposed biosynthetic sequence has been constructed from age-related quantitative dynamics of individual intermediates and confirmed by the detection of labeled products downstream of the administered labeled intermediates. Comparative RNA-Seq analyses followed by qRT-PCR validation identified orthologs of serine palmitoyltransferase and 3-ketodihydrosphingosine reductase genes as highly expressed in the NPD production site, i.e. the frontal gland of soldiers. A dramatic onset of expression of the two genes in the first days of soldier's life coincides with the start of NPD biosynthesis, giving further support to the proposed biosynthetic hypothesis.
      Graphical abstract image

      PubDate: 2017-01-23T10:33:11Z
      DOI: 10.1016/j.ibmb.2017.01.008
       
  • Mutations of two acidic residues at the cytoplasmic end of segment IIIS6
           of an insect sodium channel have distinct effects on pyrethroid resistance
           
    • Authors: Mengli Chen; Yuzhe Du; Yoshiko Nomura; Guonian Zhu; Boris S. Zhorov; Ke Dong
      Abstract: Publication date: Available online 20 January 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Mengli Chen, Yuzhe Du, Yoshiko Nomura, Guonian Zhu, Boris S. Zhorov, Ke Dong
      Mutations in sodium channels are known to confer knockdown resistance to pyrethroid insecticides, such as permethrin and cypermethrin, in various agricultural pests and disease vectors. Double mutations, D3i28V and E3i32G, were detected in cypermethrin-resistant Helicoverpa armigera and Heliothis virescens populations. However, the role of the two mutations in pyrethroid resistance remains unclear. In this study, we introduced the mutations into the cockroach sodium channel, BgNav1-1a, and examined their effects on channel gating and pyrethroid sensitivity in Xenopus oocytes. D3i28V alone and the double mutation, D3i28V/E3i32G, shifted the voltage dependence of activation in the depolarizing direction by 15 mV and 20 mV, respectively, whereas E3i32G had no significant effect. D3i28V reduced the amplitude of tail currents induced by permethrin and NRDC 157 (Type I pyrethroids) and deltamethrin and cypermethrin (Type II pyrethroids), whereas E3i32G alone had no effect. Intriguingly, the amplitude of Type II pyrethroid-induced tail current from D3i28V/E3i32G channels was similar to that of BgNav1-1a channels, but the decay of the tail currents was accelerated. Such effects were not observed for Type I pyrethroid-induced tail currents. Computational analysis based on the model of dual pyrethroid receptors on insect sodium channels predicted D3i28V and E3i32G exert their effects on channel gating and pyrethroid action via allosteric mechanisms. Our results not only illustrate the distinct effect of the D3i28V/E3i32G double mutations on Type I vs. Type II pyrethroids, but also reinforce the concept that accelerated decay of tail currents can be an effective mechanism of pyrethroid resistance to Type II pyrethroids.
      Graphical abstract image

      PubDate: 2017-01-23T10:33:11Z
      DOI: 10.1016/j.ibmb.2017.01.007
       
  • Comparative analysis of the brain transcriptome in a hyper-aggressive
           fruit fly, Drosophila prolongata
    • Authors: Ayumi Kudo; Shuji Shigenobu; Koji Kadota; Masafumi Nozawa; Tomoko F. Shibata; Yukio Ishikawa; Takashi Matsuo
      Abstract: Publication date: Available online 20 January 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Ayumi Kudo, Shuji Shigenobu, Koji Kadota, Masafumi Nozawa, Tomoko F. Shibata, Yukio Ishikawa, Takashi Matsuo
      Aggressive behavior is observed in many animals, but its intensity differs between species. In a model animal of genetics, Drosophila melanogaster, genetic basis of aggressive behavior has been studied intensively, including transcriptome analyses to identify genes whose expression level was associated with intra-species variation in aggressiveness. However, whether these genes are also involved in the evolution of aggressiveness among different species has not been examined. In this study, we performed de novo transcriptome analysis in the brain of Drosophila prolongata to identify genes associated with the evolution of aggressiveness. Males of D. prolongata were hyper-aggressive compared with closely related species. Comparison of the brain transcriptomes identified 21 differentially expressed genes in males of D. prolongata. They did not overlap with the list of aggression-related genes identified in D. melanogaster, suggesting that genes involved in the evolution of aggressiveness were independent of those associated with the intra-species variation in aggressiveness in Drosophila. Although females of D. prolongata were not aggressive as the males, expression levels of the 21 genes identified in this study were more similar between sexes than between species.
      Graphical abstract image

      PubDate: 2017-01-23T10:33:11Z
      DOI: 10.1016/j.ibmb.2017.01.006
       
 
 
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