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BIOCHEMISTRY (231 journals)                  1 2 | Last

Showing 1 - 200 of 231 Journals sorted alphabetically
AAPS PharmSciTech     Hybrid Journal   (Followers: 5)
Acetic Acid Bacteria     Open Access   (Followers: 2)
ACS Central Science     Open Access   (Followers: 6)
ACS Chemical Biology     Full-text available via subscription   (Followers: 225)
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: 18)
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: 156)
Angiogenesis     Hybrid Journal   (Followers: 3)
Annals of Clinical Biochemistry     Hybrid Journal   (Followers: 7)
Annual Review of Biochemistry     Full-text available via subscription   (Followers: 52)
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: 6)
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: 274)
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     Full-text available via subscription   (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: 23)
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: 33)
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: 4)
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: 5)
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: 44)
Journal of Biological Chemistry     Full-text available via subscription   (Followers: 189)
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: 3)
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: 166)
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: 87)
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  [3031 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)
  • 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 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)
  • Orcokinin neuropeptides regulate ecdysis in the hemimetabolous insect
           Rhodnius prolixus
    • Authors: Juan Pedro Wulff; Ivana Sierra; Marcos Sterkel; Michiel Holtof; Pieter Van Wielendaele; Flavio Francini; Jozef Vanden Broeck; Sheila Ons
      Pages: 91 - 102
      Abstract: Publication date: February 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 81
      Author(s): Juan Pedro Wulff, Ivana Sierra, Marcos Sterkel, Michiel Holtof, Pieter Van Wielendaele, Flavio Francini, Jozef Vanden Broeck, Sheila Ons
      To grow and develop insects must undergo ecdysis. During this process, the individual sheds the old cuticle to emerge as the following developmental stage. During ecdysis, different programed behaviors are regulated by neuropeptidergic pathways. In general, components of these pathways are better characterized in crustacean and holometabolous insects than in hemimetabola. In insects, the orkoninin gene produces two different neuropeptide precursors by alternative splicing: orcokinin A and orcokinin B. Although orcokinins are well conserved in insect species, their physiological role remains elusive. Here we describe a new splicing variant of the orcokinin gene in the hemimetabolous triatomine Rhodnius prolixus. We further analyze the expression pattern and the function of the alternatively spliced RhoprOK transcripts by means of immunohistochemistry and RNAi-mediated gene silencing. Our results indicate that orkoninis play an essential role in the peptidergic signaling pathway regulating ecdysis in the hemimetabolous insect Rhodnius prolixus.
      Graphical abstract image

      PubDate: 2017-01-16T09:14:29Z
      DOI: 10.1016/j.ibmb.2017.01.003
      Issue No: Vol. 81 (2017)
  • 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:
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      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.
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      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.
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      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:
    • 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.
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      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.
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      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.
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      PubDate: 2017-02-10T23:31:08Z
      DOI: 10.1016/j.ibmb.2017.02.001
  • Chemoreception to aggregation pheromones in the common bed bug, Cimex
    • 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.
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      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.
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      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.
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      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.
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      PubDate: 2017-01-23T10:33:11Z
      DOI: 10.1016/j.ibmb.2017.01.008
  • Whole genome sequence of the soybean aphid, Aphis glycines
    • Authors: Jacob A. Wenger; Bryan J. Cassone; Fabrice Legeai; J. Spencer Johnston; Raman Bansal; Ashley D. Yates; Brad S. Coates; Vitor A.C. Pavinato; Andy Michel
      Abstract: Publication date: Available online 22 January 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Jacob A. Wenger, Bryan J. Cassone, Fabrice Legeai, J. Spencer Johnston, Raman Bansal, Ashley D. Yates, Brad S. Coates, Vitor A.C. Pavinato, Andy Michel
      Aphids are emerging as model organisms for both basic and applied research. Of the 5000 estimated species, only three aphids have published whole genome sequences: the pea aphid Acyrthosiphon pisum, the Russian wheat aphid, Diuraphis noxia, and the green peach aphid, Myzus persicae. We present the whole genome sequence of a fourth aphid, the soybean aphid (Aphis glycines), which is an extreme specialist and an important invasive pest of soybean (Glycine max). The availability of genomic resources is important to establish effective and sustainable pest control, as well as to expand our understanding of aphid evolution. We generated a 302.9 Mbp draft genome assembly for Ap. glycines using a hybrid sequencing approach. This assembly shows high completeness with 19,182 predicted genes, 92% of known Ap. glycines transcripts mapping to contigs, and substantial continuity with a scaffold N50 of 174,505 bp. The assembly represents 95.5% of the predicted genome size of 317.1 Mbp based on flow cytometry. Ap. glycines contains the smallest known aphid genome to date, based on updated genome sizes for 19 aphid species. The repetitive DNA content of the Ap. glycines genome assembly (81.6 Mbp or 26.94% of the 302.9 Mbp assembly) shows a reduction in the number of classified transposable elements compared to Ac. pisum, and likely contributes to the small estimated genome size. We include comparative analyses of gene families related to host-specificity (cytochrome P450's and effectors), which may be important in Ap. glycines evolution. This Ap. glycines draft genome sequence will provide a resource for the study of aphid genome evolution, their interaction with host plants, and candidate genes for novel insect control methods.
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      PubDate: 2017-01-23T10:33:11Z
      DOI: 10.1016/j.ibmb.2017.01.005
  • 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.
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      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.
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      PubDate: 2017-01-23T10:33:11Z
      DOI: 10.1016/j.ibmb.2017.01.006
  • Knockdown of nuclease activity in the gut enhances RNAi efficiency in the
           Colorado potato beetle, Leptinotarsa decemlineata, but not in the desert
           locust, Schistocerca gregaria
    • Authors: Jornt Spit; Annelies Philips; Niels Wynant; Dulce Santos; Geert Plaetinck; Jozef Vanden Broeck
      Abstract: Publication date: Available online 14 January 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Jornt Spit, Annelies Philips, Niels Wynant, Dulce Santos, Geert Plaetinck, Jozef Vanden Broeck
      The responsiveness towards orally delivered dsRNA and the potency of a subsequent environmental RNA interference (RNAi) response strongly differs between different insect species. While some species are very sensitive to dsRNA delivery through the diet, others are not. The underlying reasons for this may vary, but degradation of dsRNA by nucleases in the gut lumen is believed to play a crucial role. The Colorado potato beetle, Leptinotarsa decemlineata, is a voracious defoliator of potato crops worldwide, and is currently under investigation for novel control methods based on dsRNA treatments. Here we describe the identification and characterization of two nuclease genes exclusively expressed in the gut of this pest species. Removal of nuclease activity in adults increased the sensitivity towards dsRNA and resulted in improved protection of potato plants. A similar strategy in the desert locust, Schistocerca gregaria, for which we show a far more potent nuclease activity in the gut juice, did however not lead to an improvement of the RNAi response. Possible reasons for this are discussed. Taken together, the present data confirm a negative effect of nucleases in the gut on the environmental RNAi response, and further suggest that interfering with this activity is a strategy worth pursuing for improving RNAi efficacy in insect pest control applications.
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      PubDate: 2017-01-16T09:14:29Z
      DOI: 10.1016/j.ibmb.2017.01.004
  • Depletion of juvenile hormone esterase extends larval growth in Bombyx
    • Authors: Zhongjie Zhang; Xiaojing Liu; Takahiro Shiotsuki; Zhisheng Wang; Xia Xu; Yongping Huang; Muwang Li; Kai Li; Anjiang Tan
      Abstract: Publication date: Available online 3 January 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Zhongjie Zhang, Xiaojing Liu, Takahiro Shiotsuki, Zhisheng Wang, Xia Xu, Yongping Huang, Muwang Li, Kai Li, Anjiang Tan
      Two major hormones, juvenile hormone (JH) and 20-hydroxyecdysone (20E), regulate insect growth and development according to their precisely coordinated titres, which are controlled by both biosynthesis and degradation pathways. Juvenile hormone esterase (JHE) is the primary JH-specific degradation enzyme that plays a key role in regulating JH titers, along with JH epoxide hydrolase (JHEH) and JH diol kinase (JHDK). In the current study, a loss-of-function analysis of JHE in the silkworm, Bombyx mori, was performed by targeted gene disruption using the transgenic CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/RNA-guided Cas9 nucleases) system. Depletion of B. mori JHE (BmJHE) resulted in the extension of larval stages, especially the penultimate and ultimate larval stages, without deleterious effects to silkworm physiology. The expression of JHEH and JHDK was upregulated in mutant animals, indicating the existence of complementary routes in the JH metabolism pathway in which inactivation of one enzyme will activate other enzymes. RNA-Seq analysis of mutant animals revealed that genes involved in protein processing in the endoplasmic reticulum and in amino acid metabolism were affected by BmJHE depletion. Depletion of JHE and subsequent delayed JH metabolism activated genes in the TOR pathway, which are ultimately responsible for extending larval growth. The transgenic Cas9 system used in the current study provides a promising approach for analysing the actions of JH, especially in nondrosophilid insects. Furthermore, prolonging larval stages produced larger larvae and cocoons, which is greatly beneficial to silk production.
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      PubDate: 2017-01-08T08:48:33Z
      DOI: 10.1016/j.ibmb.2017.01.001
  • Complete gene sequence of spider attachment silk protein (PySp1) reveals
           novel linker regions and extreme repeat homogenization
    • Authors: Ro Crystal Chaw; Christopher A. Saski; Cheryl Y. Hayashi
      Abstract: Publication date: Available online 2 January 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Ro Crystal Chaw, Christopher A. Saski, Cheryl Y. Hayashi
      Spiders use a myriad of silk types for daily survival, and each silk type has a unique suite of task-specific mechanical properties. Of all spider silk types, pyriform silk is distinct because it is a combination of a dry protein fiber and wet glue. Pyriform silk fibers are coated with wet cement and extruded into “attachment discs” that adhere silks to each other and to substrates. The mechanical properties of spider silk types are linked to the primary and higher-level structures of spider silk proteins (spidroins). Spidroins are often enormous molecules (>250 kDa) and have a lengthy repetitive region that is flanked by relatively short (∼100 amino acids), non-repetitive amino- and carboxyl-terminal regions. The amino acid sequence motifs in the repetitive region vary greatly between spidroin types, and motif length and number underlie the remarkable mechanical properties of spider silk fibers. Existing knowledge of pyriform spidroins is fragmented, making it difficult to define links between the structure and function of pyriform spidroins. Here, we present the full-length sequence of the gene encoding pyriform spidroin 1 (PySp1) from the silver garden spider Argiope argentata. The predicted protein is similar to previously reported PySp1 sequences but the A. argentata PySp1 has a uniquely long and repetitive “linker”, which bridges the amino-terminal and repetitive regions. Predictions of the hydrophobicity and secondary structure of A. argentata PySp1 identify regions important to protein self-assembly. Analysis of the full complement of A. argentata PySp1 repeats reveals extreme intragenic homogenization, and comparison of A. argentata PySp1 repeats with other PySp1 sequences identifies variability in two sub-repetitive expansion regions. Overall, the full-length A. argentata PySp1 sequence provides new evidence for understanding how pyriform spidroins contribute to the properties of pyriform silk fibers.
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      PubDate: 2017-01-08T08:48:33Z
      DOI: 10.1016/j.ibmb.2017.01.002
  • Nucleoporin Nup358 facilitates nuclear import of Methoprene-tolerant (Met)
           in an importin β- and Hsp83-dependent manner
    • Authors: Qianyu He; Yuanxi Zhang; Xu Zhang; DanDan Xu; Wentao Dong; Sheng Li; Rui Wu
      Pages: 10 - 18
      Abstract: Publication date: February 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 81
      Author(s): Qianyu He, Yuanxi Zhang, Xu Zhang, DanDan Xu, Wentao Dong, Sheng Li, Rui Wu
      The bHLH-PAS transcription factor, Methoprene-tolerant (Met)1, functions as a juvenile hormone (JH) receptor and transduces JH signals by directly binding to E-box like motifs in the regulatory regions of JH response genes. Nuclear localization of Met is crucial for its transcriptional activity. Our previous studies have shown that the chaperone protein Hsp83 facilitates JH-induced Met nuclear import in Drosophila melanogaster. However, the exact molecular mechanisms of Met nuclear transport are not fully elucidated. Using DNA affinity chromatography, we have previously detected binding of the nucleoporin Nup358, in the presence of JH, to the JH response region (JHRR) sequences isolated from the Krüppel-homolog 1 (Kr-h1) promoter. Here, we have demonstrated that Nup358 regulates JH-Hsp83-induced Met nuclear localization. RNAi-mediated knockdown of Nup358 expression in Drosophila fat body perturbs Met nuclear transport during the 3 h after initiation of wandering, when the JH titer is high. The accompanying reduced expression of the transport receptor importin β in Nup358 RNAi flies could be one of the reasons accounting for Met mislocalization. Furthermore, a tetratricopeptide repeat (TPR) domain at the N-terminal end of Nup358 interacts with Hsp83 and is indispensable for Met nuclear localization. Overexpression of the TPR domain in Drosophila fat body prevents Met nuclear localization resulting in a decrease in JHRR-driven reporter activity and Kr-h1 expression. These data show that Nup358 facilitates JH-induced Met nuclear transport in a manner dependent on importin β and Hsp83.
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      PubDate: 2016-12-30T07:47:38Z
      DOI: 10.1016/j.ibmb.2016.12.005
      Issue No: Vol. 81 (2016)
  • Clues on the function of Manduca sexta perilipin 2 inferred from
           developmental and nutrition-dependent changes in its expression
    • Authors: Xiao Chen; Sarah J. Firdaus; Alisha D. Howard; Jose L. Soulages; Estela L. Arrese
      Pages: 19 - 31
      Abstract: Publication date: February 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 81
      Author(s): Xiao Chen, Sarah J. Firdaus, Alisha D. Howard, Jose L. Soulages, Estela L. Arrese
      Cellular triglycerides (TG) are stored in cytosolic lipid droplets (LDs). Perilipins (PLIN) are a group of LD-proteins that play important roles in the assembly and transport of LDs and in TG metabolism. Two members of the PLIN family are found in insects (PLIN1 & 2 or Lsd1 & 2). We have cloned and expressed Manduca sexta PLIN2 (MsPLIN2), and studied developmental and nutritional changes in the expression of PLIN2. Nutritional changes induced fast alterations in PLIN2 mRNA and protein levels in fat body and midgut of the feeding larvae. The relationship observed between PLIN2 expression and TG synthesis in both larval fat body and midgut suggests that PLIN2 is needed when tissues are accumulating TG. However, when the fat body was storing TG at maximal capacity, MsPLIN2 levels declined. This unexpected finding suggests the occurrence of alternative mechanism/s to shield TG from the action of lipases in M. sexta LDs. In addition, it implies that the cellular level of lipid storage could be modulating MsPLIN2 expression and/or degradation. The study also confirmed that MsPLIN2 was most abundant in the adult fat body, which is characterized by a high rate of TG hydrolysis and lipid mobilization. Whether MsPLIN2 is directly involved in lipolysis and/or the secretion of lipids in the fat body of adult of M. sexta is unknown at this time. Nonetheless, the coexistence of high PLIN2 and lipolysis levels suggests a complex role for MsPLIN2. Altogether, we found that MsPLIN2 is needed when the synthesis of glycerides, DG and TG, is active even if the insect is accumulating or consuming TG.
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      PubDate: 2016-12-30T07:47:38Z
      DOI: 10.1016/j.ibmb.2016.12.001
      Issue No: Vol. 81 (2016)
  • The potential subunits involved in two subtypes of α-Bgt-resistant nAChRs
           in cockroach dorsal unpaired median (DUM) neurons
    • Authors: Huahua Sun; Yang Liu; Jian Li; Xinzhu Cang; Haibo Bao; Zewen Liu
      Pages: 32 - 40
      Abstract: Publication date: February 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 81
      Author(s): Huahua Sun, Yang Liu, Jian Li, Xinzhu Cang, Haibo Bao, Zewen Liu
      The american cockroach (Periplaneta americana) dorsal unpaired median (DUM) neurons provide an native tool to analyze the functional and pharmacological properties of ion channels and membrane receptors, such as nicotine acetylcholine receptors (nAChRs). Here the imidacloprid-activated nAChR subtypes were examined in DUM neurons by the patch-clamp technique and the potential subunits involved in important subtypes were analyzed by combining with RNA interference (RNAi) technique. Imidacloprid exerted agonist activities on one subtype in α-Bgt-sensitive nAChRs and another subtype in α-Bgt-resistant nAChRs, in which the α-Bgt-resistant subtype showed much higher sensitivity to imidacloprid than the α-Bgt-sensitive subtype, with the difference close to 200-fold. In α-Bgt-resistant nAChRs, nicotine exerted the agonist activity on two subtypes (nAChR1 and nAChR2), although imidacloprid only activated nAChR1. RNAi against Paα3, Paα8 and Paβ1 significantly reduced both imidacloprid- and nicotine-activated currents on nAChR1. In contrast, RNAi against Paα1, Paα2 and Paβ1 decreased nicotine-activated currents on nAChR2. The results indicated that, in α-Bgt-resistant nAChRs, Paα3, Paα8 and Paβ1 might be involved in the subunit composition of nAChR1, and Paα1, Paα2 and Paβ1 in nAChR2. In summary, from the present study and previous reports, we deduced that there are at least three nAChR subtypes that are sensitive to imidacloprid in the cockroach DUM neurons.
      Graphical abstract image

      PubDate: 2016-12-30T07:47:38Z
      DOI: 10.1016/j.ibmb.2016.11.009
      Issue No: Vol. 81 (2016)
  • Identification of the binding domains and key amino acids for the
           interaction of the transcription factors BmPOUM2 and BmAbd-A in Bombyx
    • Authors: Yong He; Huimin Deng; Qihao Hu; Zidan Zhu; Lin Liu; Sichun Zheng; Qisheng Song; Qili Feng
      Pages: 41 - 50
      Abstract: Publication date: February 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 81
      Author(s): Yong He, Huimin Deng, Qihao Hu, Zidan Zhu, Lin Liu, Sichun Zheng, Qisheng Song, Qili Feng
      The transcription factor BmPOUM2 interacted with another transcription factor BmAbd-A to regulate the expression of the wing cuticle protein gene BmWCP4 in Bombyx mori. In this study, the binding domains and amino acids for the interaction between BmPOUM2 and BmAbd-A were reported. Two isoforms of BmPOUM2 were identified. The short isoform (BmPOUM2-S) lacks a 114-amino acid sequence containing a POU-homeodomain and a nuclear localization signal peptide (NLS), as compared to the full-length isoform (BmPOUM2). Both BmPOUM2 and BmPOUM2-S proteins bound to the BmAbd-A through the POU-specific domain. When the six amino acids (Lys166, Gly173, Gln176, Ser192, Glu200 and Asn208) that are highly conserved in POU family genes were mutated, BmPOUM2 did not bind to BmAbd-A. BmAbd-A interacted with BmPOUM2 by the homeobox domain or the LCR2 (low complexity region) domain. When seven amino acids (Phe156/248, His158/250, Ala175/263, Cys180/265, Glu190/268, Trp196/274 and Val214/289) that are shared in the homeobox and LCR2 domains were mutated, BmAbd-A did not bind to BmPOUM2. Overexpression of either BmPOUM2 or BmAbd-A or both increased the activity of BmWCP4 promoter in CHO cells. ChIP assay and EMSA showed that BmAbd-A protein bound to the Hox cis-regulatory element in the BmWCP4 promoter, while the BmPOUM2 bound to the nearby POU CRE. A model for the interaction and action of BmPOUM2 and BmAbd-A in regulation of the BmWCP4 expression is proposed.
      Graphical abstract image

      PubDate: 2016-12-30T07:47:38Z
      DOI: 10.1016/j.ibmb.2016.12.007
      Issue No: Vol. 81 (2016)
  • Multidrug transporters and organic anion transporting polypeptides protect
           insects against the toxic effects of cardenolides
    • Authors: Simon C. Groen; Erika R. LaPlante; Nicolas M. Alexandre; Anurag A. Agrawal; Susanne Dobler; Noah K. Whiteman
      Pages: 51 - 61
      Abstract: Publication date: February 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 81
      Author(s): Simon C. Groen, Erika R. LaPlante, Nicolas M. Alexandre, Anurag A. Agrawal, Susanne Dobler, Noah K. Whiteman
      In the struggle against dietary toxins, insects are known to employ target site insensitivity, metabolic detoxification, and transporters that shunt away toxins. Specialized insects across six taxonomic orders feeding on cardenolide-containing plants have convergently evolved target site insensitivity via specific amino acid substitutions in the Na/K-ATPase. Nonetheless, in vitro pharmacological experiments have suggested a role for multidrug transporters (Mdrs) and organic anion transporting polypeptides (Oatps), which may provide a basal level of protection in both specialized and non-adapted insects. Because the genes coding for these proteins are evolutionarily conserved and in vivo genetic evidence in support of this hypothesis is lacking, here we used wildtype and mutant Drosophila melanogaster (Drosophila) in capillary feeder (CAFE) assays to quantify toxicity of three chemically diverse, medically relevant cardenolides. We examined multiple components of fitness, including mortality, longevity, and LD50, and found that, while the three cardenolides each stimulated feeding (i.e., no deterrence to the toxin), all decreased lifespan, with the most apolar cardenolide having the lowest LD50 value. Flies showed a clear non-monotonic dose response and experienced high levels of toxicity at the cardenolide concentration found in plants. At this concentration, both Mdr and Oatp knockout mutant flies died more rapidly than wildtype flies, and the mutants also experienced more adverse neurological effects on high-cardenolide-level diets. Our study further establishes Drosophila as a model for the study of cardenolide pharmacology and solidifies support for the hypothesis that multidrug and organic anion transporters are key players in insect protection against dietary cardenolides.
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      PubDate: 2016-12-30T07:47:38Z
      DOI: 10.1016/j.ibmb.2016.12.008
      Issue No: Vol. 81 (2016)
  • Heparan sulfate/heparin glycosaminoglycan binding alters inhibitory
           profile and enhances anticoagulant function of conserved Amblyomma
           americanum tick saliva serpin 19
    • Authors: Željko M. Radulović; Albert Mulenga
      Pages: 1 - 10
      Abstract: Publication date: January 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 80
      Author(s): Željko M. Radulović, Albert Mulenga
      Some serine protease inhibitor (serpin) regulators of essential life pathways bind glycosaminoglycans (GAGs) to enhance inhibitory functions and achieve physiologically relevant rates. This study demonstrates that highly conserved Amblyomma americanum tick saliva serpin 19 (AAS19), a broad-spectrum inhibitor of hemostasis and inflammation system proteases and anticoagulant, can bind heparan sulfate/heparin (HS)GAGs and that this interaction alters its function. Substrate hydrolysis and unpaired t-test analyses revealed that HSGAG binding caused rAAS19 inhibitory activity to: (i) significantly increase against blood clotting factors (f) IIa (thrombin) and fIXa, (ii) significantly reduce against fXa and fXIIa and (iii) moderate to no effect against trypsin, kallikrein, papain, and plasmin. Stoichiometry of inhibition (SI) analyses show that HSGAG binding improved the rAAS19 inhibitory efficiency against thrombin 2.7–4.3 fold as revealed by SI change from 13.19 in absence of HSGAGs to 4.83–3.04 in their presence. Our data show that HSGAG binding dramatically enhanced rAAS19 anticoagulant function. In the recalcification time assay, rAAS19 pre-incubated with HSGAGs prior to the assay, delayed plasma clotting by an additional 176–457 s above HSGAGs or rAAS19 alone. Our data suggest that formation of the HSGAGs and rAAS19 complex is important for the observed enhanced anticoagulant effect. Delay of plasma clotting was higher when HSGAGs and rAAS19 were co-incubated to allow complex formation prior to blood clotting assay as opposed to no co-incubation. We have discussed our finding with reference to tick feeding physiology and utility of the rAAS19 in blood clotting disorder therapy.
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      PubDate: 2016-12-30T07:47:38Z
      DOI: 10.1016/j.ibmb.2016.11.002
      Issue No: Vol. 80 (2016)
  • Ryanodine receptor point mutations confer diamide insecticide resistance
           in tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae)
    • Authors: Emmanouil Roditakis; Denise Steinbach; Gerald Moritz; Emmanouil Vasakis; Marianna Stavrakaki; Aris Ilias; Lidia García-Vidal; María del Rosario Martínez-Aguirre; Pablo Bielza; Evangelia Morou; Jefferson E. Silva; Wellington M. Silva; Ηerbert A.A. Siqueira; Sofia Iqbal; Bartlomiej J. Troczka; Martin S. Williamson; Chris Bass; Anastasia Tsagkarakou; John Vontas; Ralf Nauen
      Pages: 11 - 20
      Abstract: Publication date: January 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 80
      Author(s): Emmanouil Roditakis, Denise Steinbach, Gerald Moritz, Emmanouil Vasakis, Marianna Stavrakaki, Aris Ilias, Lidia García-Vidal, María del Rosario Martínez-Aguirre, Pablo Bielza, Evangelia Morou, Jefferson E. Silva, Wellington M. Silva, Ηerbert A.A. Siqueira, Sofia Iqbal, Bartlomiej J. Troczka, Martin S. Williamson, Chris Bass, Anastasia Tsagkarakou, John Vontas, Ralf Nauen
      Insect ryanodine receptors (RyR) are the molecular target-site for the recently introduced diamide insecticides. Diamides are particularly active on Lepidoptera pests, including tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae). High levels of diamide resistance were recently described in some European populations of T. absoluta, however, the mechanisms of resistance remained unknown. In this study the molecular basis of diamide resistance was investigated in a diamide resistant strain from Italy (IT-GELA-SD4), and additional resistant field populations collected in Greece, Spain and Brazil. The genetics of resistance was investigated by reciprocally crossing strain IT-GELA-SD4 with a susceptible strain and revealed an autosomal incompletely recessive mode of inheritance. To investigate the possible role of target-site mutations as known from diamondback moth (Plutella xylostella), we sequenced respective domains of the RyR gene of T. absoluta. Genotyping of individuals of IT-GELA-SD4 and field-collected strains showing different levels of diamide resistance revealed the presence of G4903E and I4746M RyR target-site mutations. These amino acid substitutions correspond to those recently described for diamide resistant diamondback moth, i.e. G4946E and I4790M. We also detected two novel mutations, G4903V and I4746T, in some of the resistant T. absoluta strains. Radioligand binding studies with thoracic membrane preparations of the IT-GELA-SD4 strain provided functional evidence that these mutations alter the affinity of the RyR to diamides. In combination with previous work on P. xylostella our study highlights the importance of position G4903 (G4946 in P. xylostella) of the insect RyR in defining sensitivity to diamides. The discovery of diamide resistance mutations in T. absoluta populations of diverse geographic origin has serious implications for the efficacy of diamides under applied conditions. The implementation of appropriate resistance management strategies is strongly advised to delay the further spread of resistance.
      Graphical abstract image

      PubDate: 2016-12-30T07:47:38Z
      DOI: 10.1016/j.ibmb.2016.11.003
      Issue No: Vol. 80 (2016)
  • Toxicity of Cry1A toxins from Bacillus thuringiensis to CF1 cells does not
           involve activation of adenylate cyclase/PKA signaling pathway
    • Authors: Leivi Portugal; Carlos Muñóz-Garay; Diana L. Martínez de Castro; Mario Soberón; Alejandra Bravo
      Pages: 21 - 31
      Abstract: Publication date: January 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 80
      Author(s): Leivi Portugal, Carlos Muñóz-Garay, Diana L. Martínez de Castro, Mario Soberón, Alejandra Bravo
      Bacillus thuringiensis (Bt) bacteria produce Cry toxins that are able to kill insect pests. Different models explaining the mode of action of these toxins have been proposed. The pore formation model proposes that the toxin creates pores in the membrane of the larval midgut cells after interaction with different receptors such as cadherin, aminopeptidase N and alkaline phosphatase and that this pore formation activity is responsible for the toxicity of these proteins. The alternative model proposes that interaction with cadherin receptor triggers an intracellular cascade response involving protein G, adenylate cyclase (AC) and protein kinase A (PKA). In addition, it was shown that Cry toxins induce a defense response in the larvae involving the activation of mitogen-activated kinases such as MAPK p38 in different insect orders. Here we analyzed the mechanism of action of Cry1Ab and Cry1Ac toxins and a collection of mutants from these toxins in the insect cell line CF1 from Choristoneura fumiferana, that is naturally sensitive to these toxins. Our results show that both toxins induced permeability of K+ ions into the cells. The initial response after intoxication with Cry1Ab and Cry1Ac toxins involves the activation of a defense response that involves the phosphorylation of MAPK p38. Analysis of activation of PKA and AC activities indicated that the signal transduction involving PKA, AC and cAMP was not activated during Cry1Ab or Cry1Ac intoxication. In contrast we show that Cry1Ab and Cry1Ac activate apoptosis. These data indicate that Cry toxins can induce an apoptotic death response not related with AC/PKA activation. Since Cry1Ab and Cry1Ac toxins affected K+ ion permeability into the cells, and that mutant toxins affected in pore formation are not toxic to CF1, we propose that pore formation activity of the toxins is responsible of triggering cell death response in CF1cells.
      Graphical abstract image

      PubDate: 2016-12-30T07:47:38Z
      DOI: 10.1016/j.ibmb.2016.11.004
      Issue No: Vol. 80 (2016)
  • The DNA chaperone HMGB1 potentiates the transcriptional activity of Rel1A
           in the mosquito Aedes aegypti
    • Authors: Anderson de Mendonça Amarante; Natapong Jupatanakul; Isabel Caetano de Abreu da Silva; Vitor Coutinho Carneiro; Amanda Roberta Revoredo Vicentino; George Dimopolous; Octávio Augusto C. Talyuli; Marcelo Rosado Fantappié
      Pages: 32 - 41
      Abstract: Publication date: January 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 80
      Author(s): Anderson de Mendonça Amarante, Natapong Jupatanakul, Isabel Caetano de Abreu da Silva, Vitor Coutinho Carneiro, Amanda Roberta Revoredo Vicentino, George Dimopolous, Octávio Augusto C. Talyuli, Marcelo Rosado Fantappié
      High Mobility Group protein 1 (HMGB1) is a non-histone, chromatin-associated nuclear protein that functions in regulating eukaryotic gene expression. We investigated the influence and mechanism of action of Aedes aegypti HMGB1 (AaHMGB1) on mosquito Rel1A-mediated transcription from target gene promoters. The DNA-binding domain (RHD) of AaRel1A was bacterially expressed and purified, and AaHMGB1 dramatically enhanced RHD binding to consensus NF-kB/Rel DNA response elements. Luciferase reporter analyses using a cecropin gene promoter showed that AaHMGB1 potentiates the transcriptional activity of AaRel1A in Aag-2 cells. Moreover, overexpression of AaHMGB1 in Aag-2 cells led to an increase in mRNA levels of antimicrobial peptide genes. In vitro GST pull-down assays revealed that the presence of DNA is a pre-requisite for assembly of a possible ternary complex containing DNA, AaHMGB1 and AaRel1A. Notably, DNA bending by AaHMGB1 enhanced the binding of AaRel1A to a DNA fragment containing a putative NF-kB/Rel response element. Importantly, AaHMGB1 was identified as a potential immune modulator in A. aegypti through AaHMGB1 overexpression or RNAi silencing in Aag-2 cells followed by bacterial challenge or through AaHMGB1 RNAi knockdown in mosquitoes followed by Dengue virus (DENV) infection. We propose a model in which AaHMGB1 bends NF-kB/Rel target DNA to recruit and allow more efficient AaRel1A binding to activate transcription of effector genes, culminating in a stronger Toll pathway-mediated response against DENV infection.
      Graphical abstract image

      PubDate: 2016-12-30T07:47:38Z
      DOI: 10.1016/j.ibmb.2016.11.006
      Issue No: Vol. 80 (2016)
  • N-glycosylation influences the catalytic activity of mosquito
           α-glucosidases associated with susceptibility or refractoriness to
           Lysinibacillus sphaericus
    • Authors: Nathaly Alexandre do Nascimento; Lígia Maria Ferreira; Tatiany Patrícia Romão; Darleide Maria da Conceição Correia; Crhisllane Rafaele dos Santos Vasconcelos; Antônio Mauro Rezende; Samara Graciane Costa; Fernando Ariel Genta; Osvaldo Pompílio de-Melo-Neto; Maria Helena Neves Lobo Silva-Filha
      Abstract: Publication date: Available online 23 December 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Nathaly Alexandre do Nascimento, Lígia Maria Ferreira, Tatiany Patrícia Romão, Darleide Maria da Conceição Correia, Crhisllane Rafaele dos Santos Vasconcelos, Antônio Mauro Rezende, Samara Graciane Costa, Fernando Ariel Genta, Osvaldo Pompílio de-Melo-Neto, Maria Helena Neves Lobo Silva-Filha
      Cqm1 and Aam1 are α-glucosidases (EC expressed in Culex quinquefasciatus and Aedes aegypti larvae midgut, respectively. These orthologs share high sequence similarity but while Cqm1 acts as a receptor for the Binary (Bin) insecticidal toxin from Lysinibacillus sphaericus, Aam1 does not bind the toxin, rendering Ae. aegypti refractory to this bacterium. Aam1 is heavily glycosylated, contrasting to Cqm1, but little is known regarding how glycosylation impacts on its function. This study aimed to compare the N-glycosylation patterns and the catalytic activities of Aam1 and Cqm1. Mutant proteins were generated where predicted Aam1 N-glycosylation sites (N-PGS) were either inserted into Cqm1 or abrogated in Aam1. The mutants validated four N-PGS which were found to localize externally on the Aam1 structure. These Aam1 and Cqm1 mutants maintained their Bin binding properties, confirming that glycosylation has no role in this interaction. The α-glucosidase activity of both proteins was next investigated, with Aam1 having a remarkably higher catalytic efficiency, influenced by changes in glycosylation. Molecular dynamics showed that glycosylated and nonglycosylated Aam1 models displayed distinct patterns that could influence their catalytic activity. Differential N-glycosylation may then be associated with higher catalytic efficiency in Aam1, enhancing the functional diversity of related orthologs.
      Graphical abstract image

      PubDate: 2016-12-30T07:47:38Z
      DOI: 10.1016/j.ibmb.2016.12.009
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