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BIOCHEMISTRY (242 journals)                  1 2 | Last

Showing 1 - 200 of 242 Journals sorted alphabetically
AAPS PharmSciTech     Hybrid Journal   (Followers: 7)
Acetic Acid Bacteria     Open Access   (Followers: 2)
ACS Central Science     Open Access   (Followers: 9)
ACS Chemical Biology     Full-text available via subscription   (Followers: 286)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 21)
Acta Biochimica Polonica     Open Access  
Acta Crystallographica Section D : Biological Crystallography     Hybrid Journal   (Followers: 10)
Acta Crystallographica Section F: Structural Biology Communications     Hybrid Journal   (Followers: 9)
Advances and Applications in Bioinformatics and Chemistry     Open Access   (Followers: 10)
Advances in Biological Chemistry     Open Access   (Followers: 8)
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: 7)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
African Journal of Biochemistry Research     Open Access   (Followers: 1)
African Journal of Chemical Education     Open Access   (Followers: 3)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
American Journal of Biochemistry     Open Access   (Followers: 9)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 69)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 15)
American Journal of Polymer Science     Open Access   (Followers: 30)
Amino Acids     Hybrid Journal   (Followers: 8)
Analytical and Bioanalytical Chemistry Research     Open Access  
Analytical Biochemistry     Hybrid Journal   (Followers: 176)
Angiogenesis     Hybrid Journal   (Followers: 3)
Annals of Clinical Biochemistry     Hybrid Journal   (Followers: 8)
Annual Review of Biochemistry     Full-text available via subscription   (Followers: 54)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 42)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 16)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Archives of Biochemistry and Biophysics     Hybrid Journal   (Followers: 20)
Archives of Insect Biochemistry and Physiology     Hybrid Journal  
Archives Of Physiology And Biochemistry     Hybrid Journal   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Bangladesh Journal of Medical Biochemistry     Open Access   (Followers: 3)
BBA Clinical     Open Access  
BBR : Biochemistry and Biotechnology Reports     Open Access   (Followers: 4)
Biocatalysis     Open Access  
Biochemical and Biophysical Research Communications     Hybrid Journal   (Followers: 23)
Biochemical and Molecular Medicine     Full-text available via subscription   (Followers: 5)
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: 24)
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
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: 344)
Biochemistry & Pharmacology : Open Access     Open Access   (Followers: 3)
Biochemistry & Physiology : Open Access     Open Access  
Biochemistry (Moscow)     Hybrid Journal   (Followers: 4)
Biochemistry (Moscow) Supplement Series A: Membrane and Cell Biology     Hybrid Journal   (Followers: 3)
Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry     Hybrid Journal   (Followers: 3)
Biochemistry and Biophysics Reports     Open Access  
Biochemistry and Cell Biology     Hybrid Journal   (Followers: 15)
Biochemistry and Molecular Biology Education     Hybrid Journal   (Followers: 6)
Biochemistry and Molecular Biology of Fishes     Full-text available via subscription   (Followers: 1)
Biochemistry Research International     Open Access   (Followers: 6)
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids     Hybrid Journal   (Followers: 7)
Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease     Hybrid Journal   (Followers: 14)
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research     Hybrid Journal   (Followers: 9)
Biochimie     Hybrid Journal   (Followers: 7)
Biochimie Open     Open Access  
Bioconjugate Chemistry     Full-text available via subscription   (Followers: 30)
BioDrugs     Full-text available via subscription   (Followers: 7)
Bioelectrochemistry     Hybrid Journal   (Followers: 2)
Biofuels     Hybrid Journal   (Followers: 11)
Biogeochemistry     Hybrid Journal   (Followers: 15)
BioInorganic Reaction Mechanisms     Hybrid Journal   (Followers: 1)
Biokemistri     Open Access  
Biological Chemistry     Partially Free   (Followers: 22)
Biomaterials Research     Open Access   (Followers: 4)
Biomedicines     Open Access   (Followers: 1)
BioMolecular Concepts     Hybrid Journal   (Followers: 2)
Bioscience, Biotechnology, and Biochemistry     Hybrid Journal   (Followers: 22)
Biosimilars     Open Access   (Followers: 1)
Biotechnology and Applied Biochemistry     Hybrid Journal   (Followers: 44)
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: 7)
Cell Chemical Biology     Hybrid Journal   (Followers: 1)
Cellular Physiology and Biochemistry     Open Access   (Followers: 3)
ChemBioChem     Hybrid Journal   (Followers: 7)
Chemical and Biological Technologies for Agriculture     Open Access  
Chemical Biology & Drug Design     Hybrid Journal   (Followers: 20)
Chemical Engineering Journal     Hybrid Journal   (Followers: 53)
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: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 31)
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: 69)
Clinical Chemistry and Laboratory Medicine     Hybrid Journal   (Followers: 62)
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: 1)
Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology     Hybrid Journal   (Followers: 6)
Comparative Biochemistry and Physiology Part D: Genomics and Proteomics     Hybrid Journal   (Followers: 2)
Comprehensive Biochemistry     Full-text available via subscription   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 11)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Current Biochemical Engineering     Hybrid Journal  
Current Chemical Biology     Hybrid Journal   (Followers: 2)
Current Medicinal Chemistry     Hybrid Journal   (Followers: 15)
Current Opinion in Chemical Biology     Hybrid Journal   (Followers: 30)
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: 57)
FEBS Open Bio     Open Access   (Followers: 3)
Fish Physiology and Biochemistry     Hybrid Journal   (Followers: 3)
Food & Function     Full-text available via subscription   (Followers: 7)
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: 17)
Green Chemistry     Full-text available via subscription   (Followers: 10)
Histochemistry and Cell Biology     Hybrid Journal   (Followers: 6)
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: 7)
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  
International Journal of Plant Research     Open Access   (Followers: 3)
International Journal of Secondary Metabolite     Open Access   (Followers: 1)
Invertebrate Immunity     Open Access   (Followers: 1)
JBIC Journal of Biological Inorganic Chemistry     Hybrid Journal   (Followers: 4)
Journal of Microbial & Biochemical Technology     Open Access   (Followers: 2)
Journal of Applied Biology & Biotechnology     Open Access   (Followers: 2)
Journal of Bioactive and Compatible Polymers     Hybrid Journal   (Followers: 3)
Journal of Biochemical and Biophysical Methods     Hybrid Journal   (Followers: 4)
Journal of Biochemistry     Hybrid Journal   (Followers: 43)
Journal of Biochemistry and Molecular Biology Research     Open Access  
Journal of Biological Chemistry     Full-text available via subscription   (Followers: 215)
Journal of Biomaterials Science, Polymer Edition     Hybrid Journal   (Followers: 9)
Journal of Carbohydrate Chemistry     Hybrid Journal   (Followers: 7)
Journal of Cellular Biochemistry     Hybrid Journal   (Followers: 5)
Journal of Chemical Biology     Hybrid Journal   (Followers: 3)
Journal of Chemical Neuroanatomy     Hybrid Journal  
Journal of Clinical Lipidology     Hybrid Journal   (Followers: 2)
Journal of Comparative Physiology B : Biochemical, Systemic, and Environmental Physiology     Hybrid Journal   (Followers: 5)
Journal of Drug Discovery and Therapeutics     Open Access  
Journal of Enzyme Inhibition and Medicinal Chemistry     Open Access   (Followers: 3)
Journal of Evolutionary Biochemistry and Physiology     Hybrid Journal   (Followers: 1)
Journal of Food and Drug Analysis     Open Access  
Journal of Forensic Toxicology and Pharmacology     Hybrid Journal   (Followers: 6)
Journal of Inborn Errors of Metabolism and Screening     Open Access  
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 7)
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: 4)
Journal of Molecular Diagnostics     Hybrid Journal   (Followers: 6)
Journal of Neurochemistry     Hybrid Journal   (Followers: 4)
Journal of Nutritional Biochemistry     Hybrid Journal   (Followers: 7)
Journal of Pediatric Biochemistry     Hybrid Journal   (Followers: 1)
Journal of Peptide Science     Hybrid Journal   (Followers: 22)
Journal of Photochemistry and Photobiology B: Biology     Hybrid Journal   (Followers: 3)
Journal of Physiobiochemical Metabolism     Hybrid Journal   (Followers: 2)
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: 6)
Journal of Wood Chemistry and Technology     Hybrid Journal   (Followers: 10)
La Rivista Italiana della Medicina di Laboratorio - Italian Journal of Laboratory Medicine     Hybrid Journal  
Lab on a Chip     Full-text available via subscription   (Followers: 38)
Laboratory Techniques in Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 4)
Marine Chemistry     Hybrid Journal   (Followers: 8)
Methods in Enzymology     Full-text available via subscription   (Followers: 12)
Molecular and Biochemical Parasitology     Hybrid Journal   (Followers: 2)
Molecular and Cellular Biochemistry     Hybrid Journal   (Followers: 6)
Molecular Aspects of Medicine     Hybrid Journal   (Followers: 3)
Molecular Informatics     Hybrid Journal   (Followers: 5)
Molecular inhibitors in targeted therapy     Open Access  
Moscow University Chemistry Bulletin     Hybrid Journal   (Followers: 1)
Mycologia     Hybrid Journal  
Mycology : An International Journal on Fungal Biology     Hybrid Journal   (Followers: 5)
Natural Products and Bioprospecting     Open Access   (Followers: 2)
Nature Chemical Biology     Full-text available via subscription   (Followers: 77)
Nature Communications     Open Access   (Followers: 222)
Neurosignals     Open Access  
New Comprehensive Biochemistry     Full-text available via subscription  
NOVA     Open Access  

        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  [3177 journals]
  • Molecular cloning, spatiotemporal and functional expression of GABA
    • Authors: Cheng-Wang Sheng; Zhong-Qiang Jia; Yoshihisa Ozoe; Qiu-Tang Huang; Zhao-Jun Han; Chun-Qing Zhao
      Pages: 18 - 27
      Abstract: Publication date: March 2018
      Source:Insect Biochemistry and Molecular Biology, Volume 94
      Author(s): Cheng-Wang Sheng, Zhong-Qiang Jia, Yoshihisa Ozoe, Qiu-Tang Huang, Zhao-Jun Han, Chun-Qing Zhao
      Insect γ-aminobutyric acid (GABA) receptor (GABAR) is one of the major targets of insecticides. In the present study, cDNAs (CsRDL1A and CsRDL2S) encoding the two isoforms of RDL subunits were cloned from the rice stem borer Chilo suppressalis. Transcripts of both genes demonstrated similar expression patterns in different tissues and developmental stages, although CsRDL2S was ∼2-fold more abundant than CsRDL1A throughout all development stages. To investigate the function of channels formed by CsRDL subunits, both genes were expressed in Xenopus laevis oocytes singly or in combination in different ratios. Electrophysiological results using a two-electrode voltage clamp demonstrated that GABA activated currents in oocytes injected with both cRNAs. The EC50 value of GABA in activating currents was smaller in oocytes co-injected with CsRDL1A and CsRDL2S than in oocytes injected singly. The IC50 value of the insecticide fluralaner in inhibiting GABA responses was smaller in oocytes co-injected with different cRNAs than in oocytes injected singly. Co-injection also changed the potency of the insecticide dieldrin in oocytes injected singly. These findings suggested that heteromeric GABARs were formed by the co-injections of CsRDL1A and CsRDL2S in oocytes. Although the presence of Ser at the 2′-position in the second transmembrane segment was responsible for the insensitivity of GABARs to dieldrin, this amino acid did not affect the potencies of the insecticides fipronil and fluralaner. These results lead us to hypothesize that C. suppressalis may adapt to insecticide pressure by regulating the expression levels of CsRDL1A and CsRDL2S and the composition of both subunits in GABARs.
      Graphical abstract image

      PubDate: 2018-02-05T15:52:24Z
      DOI: 10.1016/j.ibmb.2018.01.003
      Issue No: Vol. 94 (2018)
  • Resistance to Bacillus thuringiensis linked with a cadherin transmembrane
           mutation affecting cellular trafficking in pink bollworm from China
    • Authors: Ling Wang; Yuemin Ma; Peng Wan; Kaiyu Liu; Yutao Xiao; Jintao Wang; Shengbo Cong; Dong Xu; Kongming Wu; Jeffrey A. Fabrick; Xianchun Li; Bruce E. Tabashnik
      Pages: 28 - 35
      Abstract: Publication date: March 2018
      Source:Insect Biochemistry and Molecular Biology, Volume 94
      Author(s): Ling Wang, Yuemin Ma, Peng Wan, Kaiyu Liu, Yutao Xiao, Jintao Wang, Shengbo Cong, Dong Xu, Kongming Wu, Jeffrey A. Fabrick, Xianchun Li, Bruce E. Tabashnik
      Evolution of pest resistance reduces the efficacy of insecticidal proteins from the gram-positive bacterium Bacillus thuringiensis (Bt) used widely in sprays and transgenic crops. In some previously studied strains of three major lepidopteran pests, resistance to Bt toxin Cry1Ac is associated with mutations disrupting the extracellular or cytoplasmic domains of cadherin proteins that bind Cry1Ac in the midgut of susceptible larvae. Here we report the first case of a cadherin transmembrane mutation associated with insect resistance to Bt. We discovered this mutation in a strain of the devastating global cotton pest, the pink bollworm (Pectinophora gossypiella), derived from a field population in the Yangtze River Valley of China. The mutant allele analyzed here has a 207 base pair deletion and encodes a cadherin protein lacking its transmembrane domain. Relative to a susceptible strain, a strain homozygous for this allele had 220-fold resistance to Cry1Ac and 2.1-fold cross-resistance to Cry2Ab. On transgenic cotton plants producing Cry1Ac, no susceptible larvae survived, but the resistant strain completed its life cycle. Inheritance of resistance to Cry1Ac was autosomal, recessive and tightly linked with the cadherin gene. Transportation of cadherin protein to the cell membrane and susceptibility to Cry1Ac occurred in transfected insect cells expressing the wild type cadherin allele, but not in transfected insect cells expressing the mutant cadherin allele. The results imply that the mutant allele analyzed here confers resistance to Cry1Ac by disrupting cellular trafficking of cadherin.
      Graphical abstract image

      PubDate: 2018-03-18T20:31:17Z
      DOI: 10.1016/j.ibmb.2018.01.004
      Issue No: Vol. 94 (2018)
  • The intracellular region of silkworm cadherin-like protein is not
           necessary to mediate the toxicity of Bacillus thuringiensis Cry1Aa and
           Cry1Ab toxins
    • Authors: Haruka Endo; Satomi Adegawa; Shingo Kikuta; Ryoichi Sato
      Pages: 36 - 41
      Abstract: Publication date: March 2018
      Source:Insect Biochemistry and Molecular Biology, Volume 94
      Author(s): Haruka Endo, Satomi Adegawa, Shingo Kikuta, Ryoichi Sato
      The cadherin-like protein in lepidopteran insects, known as a receptor for Bacillus thuringiensis Cry1A toxins, is a single-pass membrane protein that can be divided into extracellular and intracellular regions. The extracellular region is important for toxin binding and oligomerization, whereas the role of the intracellular region during Cry1A intoxication is unclear. In the present study, we generated a deletion mutant of Bombyx mori cadherin-like protein (BtR175) that lacked the intracellular region to investigate its role in mediating Cry1A toxicity. Like wild-type BtR175, the mutant protein conferred susceptibility to Cry1Aa and Cry1Ab toxins in Sf9 cells, suggesting that the intracellular region is not required to mediate intoxication. The deletion mutant maintained another role of cadherin-like proteins; that it, synergistic activity with B. mori ABC transporter C2 (ABCC2) when mediating Cry1Aa and Cry1Ab toxicity. In addition, we evaluated the effects of reagents that have been reported to inhibit Cry1A toxicity (e.g., protein kinase A inhibitors, EDTA, and sucrose) on Cry1A toxicity in BtR175-expressing cells. Our results suggest that Cry1Aa-induced cell death in BtR175-expressing cells was not caused by signal transduction but by osmotic lysis. Overall, our data indicate that BtR175 mediates the toxicity of Cry1Aa and Cry1Ab toxins entirely via its extracellular region. They also indicate that the synergism between cadherin-like protein and ABCC2 occurs outside of cells or in the cell membrane.
      Graphical abstract image

      PubDate: 2018-02-15T16:15:59Z
      DOI: 10.1016/j.ibmb.2018.01.005
      Issue No: Vol. 94 (2018)
  • Leptinotarsa hormone receptor 4 (HR4) tunes ecdysteroidogenesis and
           mediates 20-hydroxyecdysone signaling during larval-pupal metamorphosis
    • Authors: Qing-Yu Xu; Qing-Wei Meng; Pan Deng; Wen-Chao Guo; Guo-Qing Li
      Pages: 50 - 60
      Abstract: Publication date: March 2018
      Source:Insect Biochemistry and Molecular Biology, Volume 94
      Author(s): Qing-Yu Xu, Qing-Wei Meng, Pan Deng, Wen-Chao Guo, Guo-Qing Li
      Hormone receptor 4 (HR4) is involved in the regulation of 20-hydroxyecdysone (20E) biosynthesis and the mediation of 20E signaling during larval-pupal transition in a holometabolan Drosophila melanogaster, whereas it acts as a repressor in 20E-responsive transcriptional cascade in a hemimetabolan, Blattella germanica. Here we characterized two HR4 splicing variants, LdHR4X1 and LdHR4X2, in a coleopteran Leptinotarsa decemlineata. LdHR4X1 was highly expressed in the prothoracic gland and epidermis while LdHR4X2 was abundantly transcribed in the nervous system. In vivo results showed that both prothoracicotropic hormone and 20E pathways transcriptionally regulated LdHR4, in an isoform-dependent pattern. RNA interference of LdHR4 at the final (fourth) larval instar, in contrast to the second- and third-instar periods, enhanced the expression of two ecdysteroidogenesis genes, increased 20E titer, upregulated transcription of five 20E-response genes, and reduced the mRNA level of Fushi tarazu-factor 1 (FTZ-F1). As a result, the fourth-instar LdHR4 RNAi larvae exhibited accelerated development and reduced body weight. Moreover, knockdown of LdHR4 at the fourth instar resulted in larval lethality and impaired pupation. Feeding of pyriproxyfen (a mimic of juvenile hormone) or silencing of a juvenile hormone degrading enzyme gene restored the normal course of ecdysteroidogenesis, duration of larval development, and body weight in fourth-instar LdHR4 RNAi larvae. The treatment partially suppressed the larval mortality but not the failure to pupate. The dual role of HR4 during larval-pupal metamorphosis appears to be evolutionarily conserved among holometabolans.
      Graphical abstract image

      PubDate: 2018-03-18T20:31:17Z
      DOI: 10.1016/j.ibmb.2017.09.012
      Issue No: Vol. 94 (2018)
  • Bombyx mori ABC transporter C2 structures responsible for the receptor
           function of Bacillus thuringiensis Cry1Aa toxin
    • Authors: Shiho Tanaka; Haruka Endo; Satomi Adegawa; Ami Iizuka; Kazuhiro Imamura; Shingo Kikuta; Ryoichi Sato
      Pages: 44 - 54
      Abstract: Publication date: December 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 91
      Author(s): Shiho Tanaka, Haruka Endo, Satomi Adegawa, Ami Iizuka, Kazuhiro Imamura, Shingo Kikuta, Ryoichi Sato
      Because Bombyx mori ABC transporter C2 (BmABCC2) has 1000-fold higher potential than B. mori cadherin-like protein as a receptor for Bacillus thuringiensis Cry1Aa toxin (Tanaka et al., 2013), the gate-opening ability of the latent pore under six extracellular loops (ECLs) of BmABCC2 was expected to be the reason for its higher potential (Heckel, 2012). In this study, cell swelling assays in Sf9 cells showed that BmABCC2 mutants lacking substrate-excreting activity retained receptor activity, indicating that the gate-opening activity of BmABCC2 is not responsible for Cry1Aa toxicity. The analysis of 29 BmABCC2 mutants demonstrated that 770DYWL773 of ECL 4 comprise a putative binding site to Cry1Aa. This suggests that specific toxicity of Cry1Aa toxin to a restricted range of lepidopteran insects is dependent on conservation and variation in the amino acid residues around 770DYWL773 of ECL 4 in the ABCC2.
      Graphical abstract image

      PubDate: 2018-02-15T16:15:59Z
      DOI: 10.1016/j.ibmb.2017.11.002
      Issue No: Vol. 91 (2018)
  • A polydnavirus-encoded ANK protein has a negative impact on
           steroidogenesis and development
    • Authors: Marilena Ignesti; Rosalba Ferrara; Patrizia Romani; Luca Valzania; Giulia Serafini; Francesco Pennacchio; Valeria Cavaliere; Giuseppe Gargiulo
      Abstract: Publication date: Available online 17 March 2018
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Marilena Ignesti, Rosalba Ferrara, Patrizia Romani, Luca Valzania, Giulia Serafini, Francesco Pennacchio, Valeria Cavaliere, Giuseppe Gargiulo
      Polydnaviruses (PDV) are viral symbionts associated with ichneumonid and braconid wasps parasitizing moth larvae, which are able to disrupt the host immune response and development, as well as a number of other physiological pathways. The immunosuppressive role of PDV has been more intensely investigated, while very little is known about the PDV-encoded factors disrupting host development. Here we address this research issue by further expanding the functional analysis of ankyrin genes encoded by the bracovirus associated with Toxoneuron nigriceps (Hymenoptera, Braconidae). In a previous study, using Drosophila melanogaster as experimental model system, we demonstrated the negative impact of TnBVank1 impairing the ecdysone biosynthesis by altering endocytic traffic in prothoracic gland cells. With a similar approach here we demonstrate that another member of the viral ank gene family, TnBVank3, does also contribute to the disruption of ecdysone biosynthesis, but with a completely different mechanism. We show that its expression in Drosophila prothoracic gland (PG) blocks the larval-pupal transition by impairing the expression of steroidogenic genes. Furthermore, we found that TnBVank3 affects the expression of genes involved in the insulin/TOR signaling and the constitutive activation of the insulin pathway in the PG rescues the pupariation impairment. Collectively, our data demonstrate that TnBVANK3 acts as a virulence factor by exerting a synergistic and non-overlapping function with TnBVANK1 to disrupt the ecdysone biosynthesis.
      Graphical abstract image

      PubDate: 2018-03-18T20:31:17Z
      DOI: 10.1016/j.ibmb.2018.03.003
  • On the biosynthetic origin of carminic acid
    • Authors: Silas A. Rasmussen; Kenneth T. Kongstad; Paiman Khorsand-Jamal; Rubini Maya Kannangara; Majse Nafisi; Alex Van Dam; Mads Bennedsen; Bjørn Madsen; Finn Okkels; Charlotte H. Gotfredsen; Dan Staerk; Ulf Thrane; Uffe H. Mortensen; Thomas O. Larsen; Rasmus J.N. Frandsen
      Abstract: Publication date: Available online 16 March 2018
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Silas A. Rasmussen, Kenneth T. Kongstad, Paiman Khorsand-Jamal, Rubini Maya Kannangara, Majse Nafisi, Alex Van Dam, Mads Bennedsen, Bjørn Madsen, Finn Okkels, Charlotte H. Gotfredsen, Dan Staerk, Ulf Thrane, Uffe H. Mortensen, Thomas O. Larsen, Rasmus J.N. Frandsen
      The chemical composition of the scale insect Dactylopius coccus was analyzed with the aim to discover new possible intermediates in the biosynthesis of carminic acid. UPLC-DAD/HRMS analyses of fresh and dried insects resulted in the identification of three novel carminic acid analogues and the verification of several previously described intermediates. Structural elucidation revealed that the three novel compounds were desoxyerythrolaccin-O-glucosyl (DE-O-Glcp ), 5,6-didehydroxyerythrolaccin 3-O-β-D-glucopyranoside (DDE-3-O-Glcp ), and flavokermesic acid anthrone (FKA). The finding of FKA in D. coccus provides solid evidence of a polyketide, rather than a shikimate, origin of coccid pigments. Based on the newly identified compounds, we present a detailed biosynthetic scheme that accounts for the formation of carminic acid (CA) in D. coccus and all described coccid pigments which share a flavokermesic acid (FK) core. Detection of coccid pigment intermediates in members of the Planococcus (mealybugs) and Pseudaulacaspis genera shows that the ability to form these pigments is taxonomically more widely spread than previously documented. The shared core-FK-biosynthetic pathway and wider taxonomic distribution suggests a common evolutionary origin for the trait in all coccid dye producing insect species.
      Graphical abstract image

      PubDate: 2018-03-18T20:31:17Z
      DOI: 10.1016/j.ibmb.2018.03.002
  • HR38, an ortholog of NR4A family nuclear receptors, mediates
           20-hydroxyecdysone regulation of carbohydrate metabolism during mosquito
    • Authors: Dujuan Dong; Yang Zhang; Vlastimil Smykal; Lin Ling; Alexander S. Raikhel
      Abstract: Publication date: Available online 9 March 2018
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Dujuan Dong, Yang Zhang, Vlastimil Smykal, Lin Ling, Alexander S. Raikhel
      The Aedes aegypti mosquito is the principal vector for many dangerous human viral diseases. Carbohydrate metabolism (CM) is essential for supplying the energy necessary for host seeking, blood digestion and rapid egg development of this vector insect. The steroid hormone 20-hydroxyecdysone (20E) and the ecdysone receptor (EcR) are important regulators of CM, coordinating it with female reproductive events. We report here that the NR4A nuclear receptor AHR38 plays a critical role in mediating these actions of 20E and EcR. AHR38 RNA interference (RNAi) depletion in female mosquitoes blocked the transcriptional activation of CM genes encoding phosphoglucomutase (PGM) and trehalose-6-phophate synthase (TPS); it caused an increase of glycogen accumulation and a decrease of the circulating sugar trehalose. This treatment also resulted in a dramatic reduction in fecundity. Considering that these phenotypes resulting from AHR38 RNAi depletion are similar to those of EcR RNAi, we investigated a possible connection between these transcription factors in CM regulation. EcR RNAi inhibits the AHR38 gene expression. Moreover, the 20E-induced EcR complex directly activates AHR38 by binding to the ecdysone response element (EcRE) in the upstream regulatory region of this gene. The present work has implicated AHR38 in the 20E-mediated control of CM and provided new insight into mechanisms of 20E regulation of metabolism during female mosquito reproduction.
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      PubDate: 2018-03-18T20:31:17Z
      DOI: 10.1016/j.ibmb.2018.02.003
  • JH biosynthesis and hemolymph titers in adult male Aedes aegypti
    • Authors: Marcela Nouzova; Veronika Michalkova; Salvador Hernández-Martínez; Crisalejandra Rivera-Perez; Cesar E. Ramirez; Francisco Fernandez-Lima; Fernando G. Noriega
      Abstract: Publication date: Available online 9 March 2018
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Marcela Nouzova, Veronika Michalkova, Salvador Hernández-Martínez, Crisalejandra Rivera-Perez, Cesar E. Ramirez, Francisco Fernandez-Lima, Fernando G. Noriega
      Juvenile hormone (JH) is a major hormonal regulator in insects. In Aedes aegypti females, JH signals the completion of the ecdysis to the adult stage and initiates reproductive processes. Although the regulation of JH synthesis and titer in Ae. aegypti females has been extensively studied, relatively little is known about changes of JH synthesis and titers in male mosquitoes, as well as on the roles of JH controlling male reproductive biology. A better understanding of male mosquito reproductive biology, including an improved knowledge of the hormonal control of reproduction, could increase the likelihood of success of male-targeting vector control programs. Using a high performance liquid chromatography coupled to electrospray tandem mass spectrometry method, we measured JH biosynthesis and hemolymph levels in male mosquitoes during pupal and adult stages. Our results revealed tightly concomitant changes in JH biosynthesis and JH hemolymph titers. Synthesis of JH III was very low in late pupae, significantly increased during the first 24 h after adult eclosion, and then remained relatively constant during the first six days after adult eclosion. Feeding high sugar diets resulted in an increase of JH synthesis and titers, and starvation significantly decreased JH synthesis, but this effect could be reversed by changing the males back to a high sugar diet. JH synthesis rates were similar in virgin and mated males, but hemolymph JH levels were different in well-nourished virgin and mated males. Starvation resulted in a significant reduction in insemination rates; with well-nourished males inseminating 2 times more females than water-fed. Giving a 20% sugar meal for 24 h to those mosquitoes that were previously starved for 6 days, caused a significant rise in insemination rates, restoring them to levels similar to those recorded for 20% fed males. These results suggest that nutrition plays a role on male fecundity, and this effect might be mediated by JH.
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      PubDate: 2018-03-18T20:31:17Z
      DOI: 10.1016/j.ibmb.2018.02.005
  • Inducible glutathione S-transferase (IrGST1) from the tick Ixodes ricinus
           is a haem-binding protein
    • Authors: Jan Perner; Jan Kotál; Tereza Hatalová; Veronika Urbanová; Pavla Bartošová-Sojková; Peter M. Brophy; Petr Kopáček
      Abstract: Publication date: Available online 9 March 2018
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Jan Perner, Jan Kotál, Tereza Hatalová, Veronika Urbanová, Pavla Bartošová-Sojková, Peter M. Brophy, Petr Kopáček
      Blood-feeding parasites are inadvertently exposed to high doses of potentially cytotoxic haem liberated upon host blood digestion. Detoxification of free haem is a special challenge for ticks, which digest haemoglobin intracellularly. Ticks lack a haem catabolic mechanism, mediated by haem oxygenase, and need to dispose of vast majority of acquired haem via its accumulation in haemosomes. The knowledge of individual molecules involved in the maintenance of haem homeostasis in ticks is still rather limited. RNA-seq analyses of the Ixodes ricinus midguts from blood- and serum-fed females identified an abundant transcript of glutathione S-transferase (gst) to be substantially up-regulated in the presence of red blood cells in the diet. Here, we have determined the full sequence of this encoding gene, ir-gst1, and found that it is homologous to the delta-/epsilon-class of GSTs. Phylogenetic analyses across related chelicerates revealed that only one clear IrGST1 orthologue could be found in each available transcriptome from hard and soft ticks. These orthologues create a well-supported clade clearly separated from other ticks' or mites’ delta-/epsilon-class GSTs and most likely evolved as an adaptation to tick blood-feeding life style. We have confirmed that IrGST1 expression is induced by dietary haem(oglobin), and not by iron or other components of host blood. Kinetic properties of recombinant IrGST1 were evaluated by model and natural GST substrates. The enzyme was also shown to bind haemin in vitro as evidenced by inhibition assay, VIS spectrophotometry, gel filtration, and affinity chromatography. In the native state, IrGST1 forms a dimer which further polymerises upon binding of excessive amount of haemin molecules. Due to susceptibility of ticks to haem as a signalling molecule, we speculate that the expression of IrGST1 in tick midgut functions as intracellular buffer of labile haem pool to ameliorate its cytotoxic effects upon haemoglobin intracellular hydrolysis.
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      PubDate: 2018-03-18T20:31:17Z
      DOI: 10.1016/j.ibmb.2018.02.002
  • Targeting symbiosis-related insect genes by RNAi in the pea aphid-Buchnera
    • Authors: Seung Ho Chung; Xiangfeng Jing; Yuan Luo; Angela E. Douglas
      Abstract: Publication date: Available online 8 March 2018
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Seung Ho Chung, Xiangfeng Jing, Yuan Luo, Angela E. Douglas
      The growth and reproduction of phloem sap-feeding insects requires the sustained function of intracellular bacteria localized in specialized cells known as bacteriocytes, giving the potential to target the bacterial symbiosis as a novel strategy for controlling sap-feeding insect pests. We focused on two genes in the pea aphid Acyrthosiphon pisum, amiD and ldcA1, which were acquired horizontally from bacteria and have the annotated function to degrade immunogenic bacterial peptidoglycan. We hypothesized that AmiD and LdcA1 function to eliminate peptidoglycan fragments released by the bacterial symbiont Buchnera inhabiting the bacteriocytes, thereby protecting the Buchnera from host attack. Consistent with this hypothesis, expression of amiD and ldcA1 is enriched in bacteriocytes and varies significantly with aphid age, conforming to an inverse curvilinear relationship for amiD and negative linear relationship for ldcA1. RNAi against amiD and ldcA1 administered orally to larval pea aphids caused a significant reduction in Buchnera abundance and activity, accompanied by depressed aphid growth rates. For RNAi experiments, the aphids were co-administered with dsRNA against an aphid nuclease nuc1, protecting the dsRNA against non-specific degradation. These experiments demonstrate that selective suppression of insect symbiosis-related gene function can reduce the performance of an insect pest. Phylogenetic analysis identified amiD and ldcA1 in sequenced genomes of other aphid species, and amiD in related groups of phloem-feeding insects, offering the opportunity for specific controls against a range of insect pests.
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      PubDate: 2018-03-18T20:31:17Z
      DOI: 10.1016/j.ibmb.2018.02.004
  • A deep insight into the male and female sialotranscriptome of adult Culex
           tarsalis mosquitoes
    • Authors: José M.C. Ribeiro; Ines Martin-Martin; Fernando R. Moreira; Kristen A. Bernard; Eric Calvo
      Abstract: Publication date: Available online 8 March 2018
      Source:Insect Biochemistry and Molecular Biology
      Author(s): José M.C. Ribeiro, Ines Martin-Martin, Fernando R. Moreira, Kristen A. Bernard, Eric Calvo
      Previously, a Sanger-based sialotranscriptome analysis of adult female Culex tarsalis was published based on ∼2000 ESTs. During the elapsed 7.5 years, pyrosequencing has been discontinued and Illumina sequences have increased considerable in size and decreased in price. We here report an Illumina-based sialotranscriptome that allowed finding the missing apyrase from the salivary transcriptome of C. tarsalis, to determine several full-length members of the 34–62 kDa family, when a single EST has been found previously, in addition to identifying many salivary families with lower expression levels that were not detected previously. The use of multiple libraries including salivary glands and carcasses from male and female organisms allowed for an unprecedented insight into the tissue specificity of transcripts, and in this particular case permitting identification of transcripts putatively associated with blood feeding, when exclusive of female salivary glands, or associated with sugar feeding, when transcripts are found upregulated in both male and female glands.
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      PubDate: 2018-03-18T20:31:17Z
      DOI: 10.1016/j.ibmb.2018.03.001
  • Tripeptides derived from reactive centre loop of potato type II protease
           inhibitors selectively inhibit midgut proteases of insect, Helicoverpa
    • Authors: Nidhi S. Saikhedkar; Rakesh S. Joshi; Ashiwini S. Bhoite; Radhika Mohandasan; Amit Kumar Yadav; Moneesha Fernandes; Kiran A. Kulkarni; Ashok P. Giri
      Abstract: Publication date: Available online 25 February 2018
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Nidhi S. Saikhedkar, Rakesh S. Joshi, Ashiwini S. Bhoite, Radhika Mohandasan, Amit Kumar Yadav, Moneesha Fernandes, Kiran A. Kulkarni, Ashok P. Giri
      Potato type II protease inhibitors (Pin-II PIs) impede the growth of lepidopteran insects by inhibiting serine protease-like enzymes in the larval gut. The three amino acid reactive centre loop (RCL) of these proteinaceous inhibitors is crucial for protease binding and is conserved across the Pin-II family. However, the molecular mechanism and inhibitory potential of the RCL tripeptides in isolation of the native protein has remained elusive. In this study, six peptides corresponding to the RCLs of the predominant Pin-II PIs were identified, synthesized and evaluated for in vitro and in vivo inhibitory activity against serine proteases of the polyphagous insect, Helicoverpa armigera. RCL peptides with sequences PRN, PRY and TRE were found to be potent inhibitors that adversely affected the growth and development of H. armigera. The binding mechanism and differential affinity of the RCL peptides with serine proteases was delineated by crystal structures of complexes of the RCL peptides with trypsin. Residues P1 and P2 of the inhibitors play a crucial role in the interaction and specificity of these inhibitors. Important features of RCL peptides like higher inhibition of insect proteases, enhanced efficacy at alkaline gut pH, longer retention and high stability in insect gut make them suitable molecules for the development of sustainable pest management strategies for crop protection.
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      PubDate: 2018-02-25T17:22:20Z
      DOI: 10.1016/j.ibmb.2018.02.001
  • The doublesex gene integrates multi-locus complementary sex determination
           signals in the Japanese ant, Vollenhovia emeryi
    • Authors: Misato Okamoto Miyakawa; Koji Tsuchida; Hitoshi Miyakawa
      Abstract: Publication date: Available online 2 February 2018
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Misato Okamoto Miyakawa, Koji Tsuchida, Hitoshi Miyakawa
      A female diploid, male haploid sex determination system (haplodiploidy) is found in hymenopteran taxa, such as ants, wasps, bees and sawflies. In this system, a single, complementary sex-determination (sl-CSD) locus functions as the primary sex-determination signal. In the taxa that has evolved this system, females and males are heterozygous and hemi/homozygous at the CSD locus, respectively. While the sl-CSD system enables females to alter sex ratios in the nest, it carries a high cost in terms of inbreeding, as individuals that are homozygous at the CSD locus become sterile diploid males. To counter this risk, some of hymenopteran species have evolved a multi-locus CSD (ml-CSD) system, which effectively reduces the proportion of sterile males. However, the mechanism by which these multiple primary signals are integrated and how they affect the terminal sex-differentiation signal of the molecular cascade have not yet been clarified. To resolve these questions, we examined the molecular cascade in the Japanese ant Vollenhovia emeryi, which we previously confirmed has two CSD loci. Here, we showed that the sex-determination gene, doublesex (dsx), which is highly conserved among phylogenetically distant taxa, is responsible for integrating two CSD signals in V. emeryi. After identifying and characterizing dsx, genotypes containing two CSD loci and splicing patterns of dsx were found to correspond to the sexual phenotype, suggesting that two primary signals are integrated into dsx. These findings will facilitate future molecular and functional studies of the sex determination cascade in V. emeryi, and shed light on the evolution and diversification of sex determination systems in insects.
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      PubDate: 2018-02-05T15:52:24Z
      DOI: 10.1016/j.ibmb.2018.01.006
  • Identification of yellow gene family in Agrotis ipsilon and functional
           analysis of Aiyellow-y by CRISPR/Cas9
    • Authors: Xi'en Chen; Yanghui Cao; Shuai Zhan; Yong Zhang; Anjiang Tan; Yongping Huang
      Abstract: Publication date: Available online 11 January 2018
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Xi'en Chen, Yanghui Cao, Shuai Zhan, Yong Zhang, Anjiang Tan, Yongping Huang
      The yellow gene family has been identified in several model insects, but yellow genes were poorly identified in non-model insects and the functions of yellow genes are largely unknown. In this study, we identified seven yellow genes in an important agricultural pest Agrotis ipsilon. Each gene encodes a protein containing a major royal jelly domain. Phylogenetic analysis defined these genes as yellow-y, -b, -b2, -c, -d, -e, and –h, respectively. The A. ipsilon yellow genes yellow-b, -b2, and –c were stably expressed in all developmental stages and tissues analyzed, whereas the other four yellow genes had unique expression patterns, suggesting distinct physiological roles of each gene. Using the CRISPR/Cas9 system, we successfully disrupted yellow-y in A. ipsilon and obtained G0 insects with somatic mutations. Unlike the black of wild-type newly hatched larvae and of adults, the mutants were yellow, although in the pupal stage mutant coloration did not differ from wild-type coloration. This phenotype was inherited by G1 offspring. The G0 mutants did not show any growth deficiency compared with control insects; however, a dehydration-like phenotype was observed in newly hatched G1 larvae from sibling crossed mutants. Our results indicate that A. ipsilon yellow-y gene plays a role in body pigmentation and also might function in waterproofing.
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      PubDate: 2018-01-25T15:37:46Z
      DOI: 10.1016/j.ibmb.2018.01.002
  • Brochosomins and other novel proteins from brochosomes of leafhoppers
           (Insecta, Hemiptera, Cicadellidae)
    • Authors: Roman Rakitov; Alexander A. Moysa; Arthur T. Kopylov; Sergei A. Moshkovskii; Ralph S. Peters; Karen Meusemann; Bernhard Misof; Christopher H. Dietrich; Kevin P. Johnson; Lars Podsiadlowski; Kimberly K.O. Walden
      Abstract: Publication date: Available online 10 January 2018
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Roman Rakitov, Alexander A. Moysa, Arthur T. Kopylov, Sergei A. Moshkovskii, Ralph S. Peters, Karen Meusemann, Bernhard Misof, Christopher H. Dietrich, Kevin P. Johnson, Lars Podsiadlowski, Kimberly K.O. Walden
      Brochosomes (BS) are secretory granules resembling buckyballs, produced intracellularly in specialized glandular segments of the Malpighian tubules and forming superhydrophobic coatings on the integuments of leafhoppers (Hemiptera, Cicadellidae). Their composition is poorly known. Using a combination of SDS-PAGE, LC-MS/MS, next-generation sequencing (RNAseq) and bioinformatics we demonstrate that the major structural component of BS of the leafhopper Graphocephala fennahi Young is a novel family of 21–40-kDa secretory proteins, referred to herein as brochosomins (BSM), apparently cross-linked by disulfide bonds. At least 28 paralogous BSM were identified in a transcriptome assembly of this species, most of which were detected in BS. Multiple additional BS-associated proteins (BSAP), possibly loosely attached to the outer and inner surfaces of BS, were also identified; some of these were glycine-, tyrosine- and proline-rich. BSM and BSAP together accounted for half of the 100 most expressed transcripts in the Malpighian tubules of G. fennahi. Except for several minor BSAP possibly related to cyclases, BSM and BSAP had no homologs among known proteins, thus representing taxonomically restricted gene families (orphans). Searching in 50 whole-body transcriptome assemblies of Hemiptera found homologs of BSM in representatives of all five families of the superfamily Membracoidea (Cicadellidae, Myerslopiidae, Aetalionidae, Membracidae, and Melizoderidae), but not in other lineages. Among the identified proteins only BSM were shared in common between all 17 surveyed leafhoppers known to produce BS. Combined CHN elemental and aminoacid analyses estimated the total protein content of BS from the integument of G. fennahi to be 60–70%.
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      PubDate: 2018-01-25T15:37:46Z
      DOI: 10.1016/j.ibmb.2018.01.001
  • MicroRNA-14 regulates larval development time in Bombyx mori
    • Authors: Zulian Liu; Lin Ling; Jun Xu; Baosheng Zeng; Yongping Huang; Peng Shang; Anjiang Tan
      Abstract: Publication date: Available online 27 December 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Zulian Liu, Lin Ling, Jun Xu, Baosheng Zeng, Yongping Huang, Peng Shang, Anjiang Tan
      MicroRNAs (miRNA) regulate multiple physiological processes including development and metamorphosis in insects. In the current study, we demonstrate that a conserved invertebrate miRNA-14 (miR-14) plays an important role in ecdysteroid regulated development in the silkworm Bombyx mori, a lepidopteran model insect. Ubiquitous transgenic overexpression of miR-14 using the GAL4/UAS system resulted in delayed silkworm larval development and smaller body size of larva and pupa with decrease in ecdysteriod titers. On the contrary, miR-14 disruption using the transgenic CRISPR/Cas9 system led to a precocious wandering stage with increase in ecdysteriod titers. We identified that the hormone receptor E75 (E75) and the ecdysone receptor isoform B (ECR-B), which both serve as essential mediators in the ecdysone signaling pathway, as putative target genes of miR-14 by in silico target prediction. Dual-luciferase reporter assays confirmed the binding of miR-14 to the 3′UTRs of E75 and ECR-B in a mammalian HEK293T cell line. Furthermore, transcription levels of E75 and ECR-B were significantly affected in both miR-14 overexpression and knockout transgenic animals. Taken together, our data suggested that the canonical invertebrate miR-14 is a general regulator in maintaining ecdysone homeostasis for normal development and metamorphosis in B. mori.
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      PubDate: 2018-01-03T10:58:17Z
      DOI: 10.1016/j.ibmb.2017.12.009
  • Juvenile hormone-independent function of Krüppel homolog 1 in early
           development of water flea Daphnia pulex
    • Authors: Hitoshi Miyakawa; Minae Watanabe; Marina Araki; Yukiko Ogino; Shinichi Miyagawa; Taisen Iguchi
      Pages: 12 - 18
      Abstract: Publication date: February 2018
      Source:Insect Biochemistry and Molecular Biology, Volume 93
      Author(s): Hitoshi Miyakawa, Minae Watanabe, Marina Araki, Yukiko Ogino, Shinichi Miyagawa, Taisen Iguchi
      Elaborate regulation of insect metamorphosis is the consequence of physiological cooperation among multiple endocrine factors such as juvenile hormones (JHs) and ecdysteroids. Hormone-induced transcription factors play important roles in substantive interactions between hormonal signaling pathways. In insects, zinc finger transcription factor Krüppel homolog 1 (Kr-h1) is a key gene of the endocrine signaling pathway in which it is directly upregulated by JH receptor Methoprene-tolerant (Met) in the presence of JH and then regulates multiple downstream factors, including components of the ecdysteroid signaling pathway. Although JH also plays a role in various biological phenomena in other arthropod species, little is known about the molecular basis of the JH signaling pathway. Here we cloned Kr-h1 from a branchiopod crustacean, Daphnia pulex, (DappuKr-h1) and analyzed its expression profile and developmental function together with consideration of its relationship to the JH signaling pathway. We suggest that DappuKr-h1 lacks JH responsiveness and regulatory relationship with the JH receptor. Moreover our loss-of-function analysis revealed that maternal mRNA of DappuKr-h1 plays a critical role in early development independent from the JH signaling pathway. These findings provide insights about whether and how the JH signaling pathway influenced evolution, leading to greater diversity in phylum Arthropoda.
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      PubDate: 2017-12-24T15:36:02Z
      DOI: 10.1016/j.ibmb.2017.12.007
      Issue No: Vol. 93 (2017)
  • DNA methylation affects the lifespan of honey bee (Apis mellifera L.)
           workers – Evidence for a regulatory module that involves vitellogenin
           expression but is independent of juvenile hormone function
    • Authors: Carlos A.M. Cardoso-Júnior; Karina R. Guidugli-Lazzarini; Klaus Hartfelder
      Pages: 21 - 29
      Abstract: Publication date: January 2018
      Source:Insect Biochemistry and Molecular Biology, Volume 92
      Author(s): Carlos A.M. Cardoso-Júnior, Karina R. Guidugli-Lazzarini, Klaus Hartfelder
      The canonic regulatory module for lifespan of honey bee (Apis mellifera) workers involves a mutual repressor relationship between juvenile hormone (JH) and vitellogenin (Vg). Compared to vertebrates, however, little is known about a possible role of epigenetic factors. The full genomic repertoire of DNA methyltransferases (DNMTs) makes the honey bee an attractive emergent model for studying the role of epigenetics in the aging process of invertebrates, and especially so in social insects. We first quantified the transcript levels of the four DNMTs encoding genes in the head thorax and abdomens of workers of different age, showing that dnmt1a and dnmt3 expression is up-regulated in abdomens of old workers, whereas dnmt1b and dnmt2 are down-regulated in heads of old workers. Pharmacological genome demethylation by RG108 treatment caused an increase in worker lifespan. Next, we showed that the genomic DNA methylation status indirectly affects vitellogenin gene expression both in vitro and in vivo in young workers, and that this occurs independent of caloric restriction or JH levels, suggesting that a non-canonical circuitry may be acting in parallel with the JH/Vg module to regulate the adult life cycle of honey bee workers. Our data provide evidence that epigenetic factors play a role in regulatory networks associated with complex life history traits of a social insect.
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      PubDate: 2017-12-07T13:22:28Z
      DOI: 10.1016/j.ibmb.2017.11.005
      Issue No: Vol. 92 (2017)
  • Upregulation of Aedes aegypti Vago1 by Wolbachia and its effect on dengue
           virus replication
    • Authors: Sultan Asad; Rhys Parry; Sassan Asgari
      Pages: 45 - 52
      Abstract: Publication date: January 2018
      Source:Insect Biochemistry and Molecular Biology, Volume 92
      Author(s): Sultan Asad, Rhys Parry, Sassan Asgari
      Dengue infection along with its related disease conditions poses a significant threat to human health. The pathogen responsible for this infection is dengue virus (DENV) which is primarily transmitted to humans through the bites of Aedes aegypti mosquitoes. Unavailability of a potent vaccine has recently sparked renewed research endeavours aimed at vector control. To date, Wolbachia as an endosymbiotic bacterium has shown promise as a novel biocontrol agent to restrict DENV replication in the vector, although the underlying antiviral mechanism remains elusive. Recent studies have demonstrated the potential role of Vago as a novel secretory protein involved in cross-talk between the innate immune pathways in Culex quinquefasciatus mosquitoes to restrict West Nile virus replication. In this study, we have identified two homologs of the Vago protein in Ae. aegypti and looked into their modulation in the case of Wolbachia wMelPop strain infection. Furthermore, we have investigated the role of AeVago1, that is highly induced by Wolbachia, in the context of Wolbachia-mosquito-DENV interactions. Knockdown studies of the AeVago1 gene in Wolbachia-infected cells led to significant increases in DENV replication, with no effect on Wolbachia density. Our results suggest that the Wolbachia-induced AeVago1 in Ae. aegypti may function as a host factor to suppress DENV replication in the mosquito.
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      PubDate: 2017-12-07T13:22:28Z
      DOI: 10.1016/j.ibmb.2017.11.008
      Issue No: Vol. 92 (2017)
  • 20-Hydroxyecdysone promotes release of GBP-binding protein from
           oenocytoids to suppress hemocytic encapsulation
    • Authors: Xiao-Rong Zhuo; Lei Chen; Gui-Jie Wang; Xu-Sheng Liu; Yu-Feng Wang; Ke Liu; Xiao-Qiang Yu; Jia-Lin Wang
      Pages: 53 - 64
      Abstract: Publication date: January 2018
      Source:Insect Biochemistry and Molecular Biology, Volume 92
      Author(s): Xiao-Rong Zhuo, Lei Chen, Gui-Jie Wang, Xu-Sheng Liu, Yu-Feng Wang, Ke Liu, Xiao-Qiang Yu, Jia-Lin Wang
      Growth-blocking peptide (GBP) is an insect cytokine that stimulates plasmatocyte adhesion, thereby playing a critical role in encapsulation reaction. It has been previously demonstrated that GBP-binding protein (GBPB) is released upon oenocytoid lysis in response to GBP and is responsible for subsequent clearance of GBP from hemolymph. However, current knowledge about GBPB is limited and the mechanism by which insects increase GBPB levels to inactivate GBP remains largely unexplored. Here, we have identified one GBP precursor (HaGBP precursor) gene and two GBPB (namely HaGBPB1 and HaGBPB2) genes from the cotton bollworm, Helicoverpa armigera. The HaGBP precursor was found to be predominantly expressed in fat body, whereas HaGBPB1 and HaGBPB2 were mainly expressed in hemocytes. Immunological analyses indicated that both HaGBPB1 and HaGBPB2 are released from hemocytes into the plasma during the wandering stage. Additionally, 20-hydroxyecdysone (20E) treatment or bead challenge could promote the release of HaGBPB1 and HaGBPB2 at least partly from oenocytoids into the plasma. Furthermore, we demonstrate that the N-terminus of HaGBPB1 is responsible for binding to HaGBP and suppresses HaGBP-induced plasmatocyte spreading and encapsulation. Overall, this study helps to enrich our understanding of the molecular mechanism underlying 20E mediated regulation of plasmatocyte adhesion and encapsulation via GBP-GBPB interaction.
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      PubDate: 2017-12-07T13:22:28Z
      DOI: 10.1016/j.ibmb.2017.11.006
      Issue No: Vol. 92 (2017)
  • Bombyx ortholog of the Drosophila eye color gene brown controls riboflavin
           transport in Malpighian tubules
    • Authors: Haokun Zhang; Takashi Kiuchi; Chikara Hirayama; Susumu Katsuma; Toru Shimada
      Pages: 65 - 72
      Abstract: Publication date: January 2018
      Source:Insect Biochemistry and Molecular Biology, Volume 92
      Author(s): Haokun Zhang, Takashi Kiuchi, Chikara Hirayama, Susumu Katsuma, Toru Shimada
      The Drosophila eye color gene brown is known to control the transport of pteridine precursors in adult eyes. The Brown protein belongs to the ATP-binding cassette (ABC) transporter G family, which includes proteins encoded by the genes brown, scarlet, and white. These genes are responsible for pigmentation in Drosophila and the domestic silkworm Bombyx mori. Although orthologs of brown are conserved among insects, the function of this gene is only known in Drosophila. Here, we elucidated the function of the B. mori ortholog Bm-brown. We examined the spatial and temporal expression profiles of Bm-brown and found that this gene was specifically and continuously expressed in larval Malpighian tubules (MTs), indicating this gene has a special function in MTs. We then successfully obtained a Bm-brown knockout (KO) strain based on a wild-type (WT) strain using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated nuclease 9 (Cas9) system. We found that larval MTs of the KO strain were white, whereas those of WT were yellow. It is known that larval yellow MTs of WT are due to the accumulation of riboflavin. Therefore, we compared the riboflavin contents of MTs of KO and WT strains, and found that the riboflavin level in the KO strain was 20 fold less than that in WT during the 5th instar period. MTs are known to exhibit a similar milky color in w-3 mutant larvae due to a deficiency of riboflavin accumulation. The responsible gene for w-3 mutant is the Bmwh3 gene, which is orthologous to Drosophila white. Thus, we speculate that Bm-brown is heterodimerized with Bmwh3, similar to Brown/White in Drosophila, and acts as a riboflavin transporter in silkworm MTs.
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      PubDate: 2017-12-07T13:22:28Z
      DOI: 10.1016/j.ibmb.2017.11.012
      Issue No: Vol. 92 (2017)
  • Crystal structure of ryanodine receptor N-terminal domain from Plutella
           xylostella reveals two potential species-specific insecticide-targeting
    • Authors: Lianyun Lin; Chen Liu; Juan Qin; Jie Wang; Shengjie Dong; Wei Chen; Weiyi He; Qingzhi Gao; Minsheng You; Zhiguang Yuchi
      Pages: 73 - 83
      Abstract: Publication date: January 2018
      Source:Insect Biochemistry and Molecular Biology, Volume 92
      Author(s): Lianyun Lin, Chen Liu, Juan Qin, Jie Wang, Shengjie Dong, Wei Chen, Weiyi He, Qingzhi Gao, Minsheng You, Zhiguang Yuchi
      Ryanodine receptors (RyRs) are large calcium-release channels located in sarcoplasmic reticulum membrane. They play a central role in excitation-contraction coupling of muscle cells. Three commercialized insecticides targeting pest RyRs generate worldwide sales over 2 billion U.S. dollars annually, but the structure of insect RyRs remains elusive, hindering our understanding of the mode of action of RyR-targeting insecticides and the development of insecticide resistance in pests. Here we present the crystal structure of RyR N-terminal domain (NTD) (residue 1–205) at 2.84 Å resolution from the diamondback moth (DBM), Plutella xylostella, a destructive pest devouring cruciferous crops all over the world. Similar to its mammalian homolog, DBM RyR NTD consists of a beta-trefoil folding motif and a flanking alpha helix. Interestingly, two regions in NTD interacting with neighboring domains showed distinguished conformations in DBM relative to mammalian RyRs. Using homology modeling and molecular dynamics simulation, we created a structural model of the N-terminal three domains, showing two unique binding pockets that could be targeted by potential species-specific insecticides. Thermal melt experiment showed that the stability of DBM RyR NTD was higher than mammalian RyRs, probably due to a stable intra-domain disulfide bond observed in the crystal structure. Previously DBM NTD was shown to be one of the two critical regions to interact with insecticide flubendiamide, but isothermal titration calorimetry experiments negated DBM NTD alone as a major binding site for flubendiamide.
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      PubDate: 2017-12-07T13:22:28Z
      DOI: 10.1016/j.ibmb.2017.11.009
      Issue No: Vol. 92 (2017)
  • Development and ultrastructure of the rigid dorsal and flexible ventral
           cuticles of the elytron of the red flour beetle, Tribolium castaneum
    • Authors: Mi Young Noh; Subbaratnam Muthukrishnan; Karl J. Kramer; Yasuyuki Arakane
      Pages: 21 - 33
      Abstract: Publication date: December 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 91
      Author(s): Mi Young Noh, Subbaratnam Muthukrishnan, Karl J. Kramer, Yasuyuki Arakane
      Insect exoskeletons are composed of the cuticle, a biomaterial primarily formed from the linear and relatively rigid polysaccharide, chitin, and structural proteins. This extracellular material serves both as a skin and skeleton, protecting insects from environmental stresses and mechanical damage. Despite its rather limited compositional palette, cuticles in different anatomical regions or developmental stages exhibit remarkably diverse physicochemical and mechanical properties because of differences in chemical composition, molecular interactions and morphological architecture of the various layers and sublayers throughout the cuticle including the envelope, epicuticle and procuticle (exocuticle and endocuticle). Even though the ultrastructure of the arthropod cuticle has been studied rather extensively, its temporal developmental pattern, in particular, the synchronous development of the functional layers in different cuticles during a molt, is not well understood. The beetle elytron, which is a highly modified and sclerotized forewing, offers excellent advantages for such a study because it can be easily isolated at precise time points during development. In this study, we describe the morphogenesis of the dorsal and ventral cuticles of the elytron of the red flour beetle, Tribolium castaneum, during the period from the 0 d-old pupa to the 9 d-old adult. The deposition of exocuticle and mesocuticle is substantially different in the two cuticles. The dorsal cuticle is four-fold thicker than the ventral. Unlike the ventral cuticle, the dorsal contains a thicker exocuticle consisting of a large number of horizontal laminae and vertical pore canals with pore canal fibers and rib-like veins and bristles as well as a mesocuticle, lying right above the enodcuticle. The degree of sclerotization appears to be much greater in the dorsal cuticle. All of these differences result in a relatively thick and tanned rigid dorsal cuticle and a much thinner and less pigmented membrane-like ventral cuticle.
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      PubDate: 2017-11-09T11:48:23Z
      DOI: 10.1016/j.ibmb.2017.11.003
      Issue No: Vol. 91 (2017)
  • Environmental and hormonal control of body color polyphenism in
           late-instar desert locust nymphs: Role of the yellow protein
    • Authors: Ryohei Sugahara; Seiji Tanaka; Akiya Jouraku; Takahiro Shiotsuki
      Pages: 5 - 11
      Abstract: Publication date: Available online 14 December 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Ryohei Sugahara, Seiji Tanaka
      Locusts show body color polyphenism that is considered to be an adaptation to various biotic and abiotic environmental changes. In Schistocerca gregaria, wild-type late-instar nymphs growing under crowded conditions (gregarious form) develop yellow and black body coloration, whereas they assume various body colors under isolated conditions (solitarious form). Black and green body colorations are induced by the neuropeptide corazonin (Crz) and juvenile hormone (JH), respectively. To characterize the molecular mechanisms controlling body color polyphenism, we investigated factors influencing body coloration in S. gregaria. We report here that yellow body coloration in the last nymphal instar is caused by the yellow protein of the takeout family (YPT) in this locust. YPT transcription was enhanced under high-temperature conditions during which the nymphs turned bright yellow and had little black patterning. RNAi-mediated YPT knockdown suppressed the appearance of yellow individuals and yellow staining in the exuviae. In albino nymphs, injection of JH induced yellow and green coloration and enhanced the YPT expression levels in both yellow and green individuals. YPT knockdown also suppressed yellow staining in the exuviae but did not prevent the appearance of yellow individuals. Therefore, another factor or pigment may contribute to the observed yellow body color. Injection of Crz into wild-type nymphs caused darkening and suppressed yellowing and YPT expression at high temperatures. Thus, Crz signaling could inhibit yellowing by suppressing YPT expression. Rearing cup substrate color significantly influenced YPT expression in albino nymphs both under isolated and crowded conditions. In contrast, substrate color affected YPT expression in wild-type nymphs only under isolated conditions. From these results, we conclude that YPT is an important factor in the control of body color polyphenism in S. gregaria, and its expression is influenced by temperature, JH, Crz, and substrate color of the developmental environment.
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      PubDate: 2017-12-24T15:36:02Z
      DOI: 10.1016/j.gene.2016.12.028
      Issue No: Vol. 605 (2017)
  • Cell lines as models for the study of Cry toxins from Bacillus
    • Authors: Mario Soberón; Leivi Portugal; Blanca-Ines Garcia-Gómez; Jorge Sánchez; Janette Onofre; Isabel Gómez; Sabino Pacheco; Alejandra Bravo
      Abstract: Publication date: Available online 19 December 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Mario Soberón, Leivi Portugal, Blanca-Ines Garcia-Gómez, Jorge Sánchez, Janette Onofre, Isabel Gómez, Sabino Pacheco, Alejandra Bravo
      Cell lines have been use extensively for the study of the mode of action of different pore forming toxins produced by different bacterial species. Bacillus thuringiensis Cry toxins are not the exception and their mechanism of action has been analyzed in different cell lines. Here we review the data obtained with different cell lines, including those that are naturally susceptible to the three domain Cry toxins (3d-Cry) and other non-susceptible cell lines that have been transformed with 3d-Cry toxin binding molecules cloned from the susceptible insects. The effects on Cry toxin action after expressing different insect gut proteins, such as glycosyl-phosphatidyl-inositol (GPI) anchored proteins (like alkaline phosphatase (ALP) aminopeptidase (APN)), or trans-membrane proteins (like cadherin (CAD) or ATP-binding cassette subfamily C member 2 (ABCC2) transporter) in cell lines showed that, with few exceptions, expression of GPI-anchored proteins do not correlated with increased susceptibility to the toxin, while the expression of CAD or ABCC2 proteins correlated with induced susceptibility to Cry toxins in the transformed cells lines. Also, that the co-expression of CAD and ABCC2 transporter induced a synergistic effect in the toxicity of 3d-Cry toxins. Overall the data show that in susceptible cell lines, the 3d-Cry toxins induce pore formation that correlates with toxicity. However, the intracellular responses remain controversial since it was shown that the same 3d-Cry toxin in different cell lines activated different responses such as adenylate cyclase-PKA death response or apoptosis. Parasporins are Cry toxins that are toxic to cancer cell lines that have structural similarities with the insecticidal Cry toxins. They belong to the 3d-Cry toxin or to MTX-like Cry toxin families but also show important differences with the insecticidal Cry proteins. Some parasporins are pore-forming toxins, and some activate apoptosis. In this review we summarized the results of the different studies about the Cry toxins mode of action using cultured cell lines and discuss their relation with the studies performed in insect larvae.
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      PubDate: 2017-12-24T15:36:02Z
      DOI: 10.1016/j.ibmb.2017.12.008
  • Phylogenetic and functional characterization of ten P450 genes from the
           CYP6AE subfamily of Helicoverpa armigera involved in xenobiotic metabolism
    • Authors: Yu Shi; Huidong Wang; Zhi Liu; Shuwen Wu; Yihua Yang; René Feyereisen; Yidong Wu
      Abstract: Publication date: Available online 16 December 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yu Shi, Huidong Wang, Zhi Liu, Shuwen Wu, Yihua Yang, René Feyereisen, Yidong Wu
      The cotton bollworm, Helicoverpa armigera, is a generalist herbivore widely distributed over the world and is a major lepidopteran pest on cotton. Studies, especially from Asia, show that it relies on cytochrome P450 monooxygenases with broad substrate specificities to protect itself from pesticides. The number of P450s may have expanded in the processes of coping with the wide diversity of phytochemicals that the insect encounters among its numerous host plants. In order to examine the metabolic capabilities of these P450s, we focused here on all ten P450s of the Helicoverpa armigera CYP6AE subfamily, which can be easily induced by plant toxins and pyrethroids. These P450s, along with cytochrome P450 reductase, were heterologously expressed in insect cells and compared functionally. In vitro metabolism showed that all CYP6AE family members can convert esfenvalerate to 4′-hydroxyesfenvalerate efficiently except CYP6AE20. In contrast, none of the recombinant CYP6AE enzymes could metabolise gossypol under our experimental conditions. Epoxidation capabilities were observed in the CYP6AE subfamily, aldrin can be converted to dieldrin at rates up to 0.45 ± 0.04 pmol/min/pmol P450. Seven P450s in this subfamily can metabolise imidacloprid, but with lower efficiency than Bemisia tabaci CYP6CM1vQ. CYP6AE20 had virtually no metabolic competence to these four compounds but could metabolise several model fluorogenic substrates. These results showed the broad substrate spectrum of H. armigera CYP6AE P450s and suggest a limited role of gossypol upon the evolution of H. armigera CYP6AE genes.

      PubDate: 2017-12-24T15:36:02Z
      DOI: 10.1016/j.ibmb.2017.12.006
  • Identification of immature stages of phlebotomine sand flies using
           MALDI-TOF MS and mapping of mass spectra during sand fly life cycle
    • Authors: Petr Halada; Kristyna Hlavackova; Vit Dvorak; Petr Volf
      Abstract: Publication date: Available online 14 December 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Petr Halada, Kristyna Hlavackova, Vit Dvorak, Petr Volf
      The aim of the study was to evaluate the potential of matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) for the species identification of sand flies at different developmental stages and map changes in their protein profiles during the course of whole life cycle. Specimens of six different species from laboratory colonies at larval and pupal stages were examined using MALDI-TOF MS. The protein profiles of larvae were stable from the L2 to L4 developmental stages and clearly distinguishable at the species level. In a validation study, 123 larvae of the six species were queried against reference database resulting in 93% correct species identification (log score values higher than 2.0). The spectra generated from sand fly pupae allow species identification as well and surprisingly, in contrast to biting midges and mosquitoes, they did not change during this developmental stage. For adults, thorax was revealed as the optimal body part for sample preparation yielding reproducible spectra regardless age and diet. Only variations were uncovered for freshly engorged females profiles of which were affected by blood signals first two days post bloodmeal. The findings demonstrate that in addition to adult species differentiation MALDI-TOF MS may also serve as a rapid and effective tool for species identification of juvenile stages of phlebotomine sand flies.
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      PubDate: 2017-12-24T15:36:02Z
      DOI: 10.1016/j.ibmb.2017.12.005
  • CRISPR/Cas9-mediated knockout of two eye pigmentation genes in the brown
           planthopper, Nilaparvata lugens (Hemiptera: Delphacidae)
    • Authors: Wen-Hua Xue; Nan Xu; Xiao-Bo Yuan; Hao-Hao Chen; Jin-Li Zhang; Sheng-Jie Fu; Chuan-Xi Zhang; Hai-Jun Xu
      Abstract: Publication date: Available online 11 December 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Wen-Hua Xue, Nan Xu, Xiao-Bo Yuan, Hao-Hao Chen, Jin-Li Zhang, Sheng-Jie Fu, Chuan-Xi Zhang, Hai-Jun Xu
      The brown planthopper Nilaparvata lugens is one of the most destructive insect pests in Asia, demonstrating high fertility and causing huge crop losses by sucking sap of rice as well as transmitting viruses. However, functional genomic studies on N. lugens are seriously constrained by lack of genetic tools. Here, we employed two eye pigmentation genes to generate germ-line mutations in N. lugens using the CRISPR/Cas9 (clustered regularly interspaced palindromic repeats/CRISPR-associated) system. We showed that injection of single guide RNA of the cinnabar gene of N. lugens (Nl-cn) into pre-blastoderm eggs induced insertion and deletion (indels) in the founder generation (G0), which were heritably transmitted to the following G1 generation, leading to bright red compound eyes and ocelli. Mutations of N. lugens white (Nl-w) generated a high mutant rate of up to 27.3%, resulting in mosaic eyes consisting of white and lightly pigmented ommatidia in both G0 and G1 individuals. The specificity of CRISPR/Cas9-mediated mutagenesis was further bolstered by PCR and RNA interference-based knockdown analysis. These results show that CRISPR/Cas9-mediated gene editing is achievable in a hemipteran insect, offering a valuable tool for the study of functional genomics and pest management in this planthopper species.
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      PubDate: 2017-12-12T14:04:16Z
      DOI: 10.1016/j.ibmb.2017.12.003
  • Receptor protein of Lysinibacillus sphaericus mosquito-larvicidal toxin
           displays amylomaltase activity
    • Authors: Mahima Sharma; Gagan D. Gupta; Vinay Kumar
      Abstract: Publication date: Available online 8 December 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Mahima Sharma, Gagan D. Gupta, Vinay Kumar
      The activated binary toxin (BinAB) from Lysinibacillus sphaericus binds to surface receptor protein (Cqm1) on the midgut cell membrane and kills Culex quinquefasciatus larvae on internalization. Cqm1 is attached to cells via a glycosyl-phosphatidylinositol (GPI) anchor. It has been classified as a member of glycoside hydrolase family 13 of the CAZy database. Here, we report characterization of the ordered domain (residues 23–560) of Cqm1. Gene expressing Cqm1 of BinAB susceptible mosquito was chemically synthesized and the protein was purified using E. coli expression system. Values for the Michaelis-Menten kinetics parameters towards 4-nitrophenyl α-D-glucopyranoside (α-pNPG) substrate were estimated to be 0.44 mM (Km) and 1.9 s−1 (kcat). Thin layer chromatography experiments established Cqm1 as α-glucosidase competent to cleave α-1,4-glycosidic bonds of maltose and maltotriose with high glycosyltransferase activity to form glucose-oligomers. The observed hydrolysis and synthesis of glucose-oligomers is consistent with open and accessible active-site in the structural model. The protein also hydrolyses glycogen and sucrose. These activities suggest that Cqm1 may be involved in carbohydrate metabolism in mosquitoes. Further, toxic BinA component does not inhibit α-glucosidase activity of Cqm1, while BinB reduced the activity by nearly 50%. The surface plasmon resonance study reveals strong binding of BinB with Cqm1 (Kd, 9.8 nM). BinA interaction with Cqm1 however, is 1000-fold weaker. Notably the estimated Kd values match well with dissociation constants reported earlier with larvae brush border membrane fractions. The Cqm1 protein forms a stable dimer that is consistent with its apical localization in lipid rafts. Its melting temperature (Tm) as observed by thermofluor-shift assay is 51.5 °C and Ca2+ provides structural stability to the protein.
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      PubDate: 2017-12-12T14:04:16Z
      DOI: 10.1016/j.ibmb.2017.12.002
  • Species specific RNA A-to-I editing of mosquito RDL modulates GABA potency
           and influences agonistic, potentiating and antagonistic actions of
    • Authors: Jennina Taylor-Wells; Anish Senan; Isabel Bermudez; Andrew K. Jones
      Abstract: Publication date: Available online 6 December 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Jennina Taylor-Wells, Anish Senan, Isabel Bermudez, Andrew K. Jones
      The insect GABA receptor, RDL, is the target of several classes of pesticides. The peptide sequences of RDL are generally highly conserved between diverse insects. However, RNA A-to-I editing can effectively alter amino acid residues of RDL in a species specific manner, which can affect the potency of GABA and possibly insecticides. We report here that RNA A-to-I editing alters the gene products of Rdl in three mosquito disease vectors, recoding five amino acid residues in RDL of Aedes aegypti and six residues in RDLs of Anopheles gambiae and Culex pipiens, which is the highest extent of editing in RDL observed to date. Analysis of An. gambiae Rdl cDNA sequences identified 24 editing isoforms demonstrating a considerable increase in gene product diversity. RNA editing influenced the potency of the neurotransmitter, GABA, on An. gambiae RDL editing isoforms expressed in Xenopus laevis oocytes, as demonstrated by EC50s ranging from 5 ± 1 to 246 ± 41 μM. Fipronil showed similar potency on different editing isoforms, with IC50s ranging from 0.18 ± 0.08 to 0.43 ± 0.09 μM. In contrast, editing of An. gambiae RDL affected the activating, potentiating and inhibiting actions of ivermectin. For example, ivermectin potentiated currents induced by GABA at the EC20 concentration in the unedited isoform but not in the fully edited variant. Editing of a residue in the first transmembrane domain or the cys-loop influenced this potentiation, highlighting residues involved in the allosteric mechanisms of cys-loop ligand-gated ion channels. Understanding the interactions of ivermectin with molecular targets may have relevance to mosquito control in areas where people are administered with ivermectin to treat parasitic diseases.
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      PubDate: 2017-12-07T13:22:28Z
      DOI: 10.1016/j.ibmb.2017.12.001
  • Structural characterization of a lepidopteran type-II farnesyl diphosphate
           synthase from the spruce budworm, Choristoneura fumiferana: Implications
           for inhibitor design
    • Authors: Marie-Ève Picard; Audrey Nisole; Catherine Béliveau; Stephanie Sen; Aline Barbar; Rong Shi; Michel Cusson
      Abstract: Publication date: Available online 26 November 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Marie-Ève Picard, Audrey Nisole, Catherine Béliveau, Stephanie Sen, Aline Barbar, Rong Shi, Michel Cusson
      Farnesyl diphosphate synthase (FPPS) is an enzyme from the class of short chain (E)-prenyltransferases that catalyzes the condensation of two molecules of isopentenyl diphosphate (IPP, C5) with dimethylallyl diphosphate (DMAPP, C5) to generate the C15 product FPP. In insects, FPPS plays a key role in the biosynthesis of the morphogenetic and gonadotropic “juvenile hormone” (JH). Lepidopteran genomes encode two very distinct FPPS paralogs, one of which (“type-II”) is expressed almost exclusively in the JH-producing glands, the corpora allata. This paralog has been hypothesized to display structural features that enable the binding of the bulkier precursors required for the biosynthesis of lepidopteran ethyl-branched JHs. Here, we report on the first crystal structures of an insect FPPS solved to date. Apo, ligand-bound, and inhibitor-bound structures of type-II FPPS (FPPS2) from the spruce budworm, Choristoneura fumiferana (Order: Lepidoptera), were obtained. Comparison of apo and inhibitor-bound enzymes revealed differences in both inhibitor binding and structural plasticity of CfFPPS2 compared to other FPPSs. Our data showed that IPP is not essential to the closure of the C-terminal tail. Ortho-substituted pyridinium bisphosphonates, previously shown to inhibit CfFPPS2, bound to the allylic site, as predicted; however, their alkyl groups were oriented towards the homoallylic binding site, with the bulkier propyl-substituted inhibitor penetrating deeply into the IPP binding pocket. The current study sheds light on the structural basis of substrate specificity of type-II FPPS of the spruce budworm. Through a comparison with other inhibitor-bound FPPSs, we propose several approaches to improve inhibitor selectivity and potency.
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      PubDate: 2017-12-07T13:22:28Z
      DOI: 10.1016/j.ibmb.2017.11.011
  • Enhanced heat tolerance in transgenic silkworm via overexpression of
           Pyrococcus furiosus superoxide reductase
    • Authors: Liang Jiang; Chunlin Huang; Bingbing Wang; Huizhen Guo; Qiang Sun; Fei Xia; Guowen Xu; Qingyou Xia
      Abstract: Publication date: Available online 21 November 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Liang Jiang, Chunlin Huang, Bingbing Wang, Huizhen Guo, Qiang Sun, Fei Xia, Guowen Xu, Qingyou Xia
      Heat shock causes a serious harm to organisms by accelerating the production of reactive oxygen species (ROS). Pyrococcus furiosus superoxide reductase (PfSOR) is an enzyme that efficiently detoxifies ROS. In order to generate a silkworm strain with high heat tolerance for sericulture, we synthesized an artificial DNA sequence encoding PfSOR based on the codon bias of Bombyx mori. PfSOR was successfully overexpressed in transgenic silkworm (named A4SOR) and BmE cells, as determined by RT-PCR and western blot analyses. An SOR activity assay confirmed that the expressed enzyme was functional in A4SOR. After exposure to a temperature of 35 °C for 44 h, the mortality rate was about 30% lower in transgenic A4SOR than in non-transgenic silkworms. Moreover, transgene expression had no apparent effect on economic characteristics of silkworms. The heat tolerance of silkworm was thus enhanced by expressing an archaeal SOR; this can be useful for sericulture in regions where the average temperature exceeds the optimal environmental temperature for B. mori of 25 °C.
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      PubDate: 2017-12-07T13:22:28Z
      DOI: 10.1016/j.ibmb.2017.11.010
  • Carboxylesterase genes in pyrethroid resistant house flies, Musca
    • Authors: Xuechun Feng; Ming Li; Nannan Liu
      Abstract: Publication date: Available online 14 November 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Xuechun Feng, Ming Li, Nannan Liu
      Carboxylesterases are one of the major enzyme families involved in the detoxification of pyrethroids. Up-regulation of carboxylesterase genes is thought to be a major component of insecticide resistant mechanisms in insects. Based on the house fly transcriptome and genome database, a total of 39 carboxylesterase genes of different functional clades have been identified in house flies. In this study, eleven of these genes were found to be significantly overexpressed in the resistant ALHF house fly strain compared with susceptible aabys and wild-type CS strains. Eight up-regulated carboxylesterase genes with their expression levels were further induced to a higher level in response to permethrin treatments, indicating that constitutive and inductive overexpression of carboxylesterase are co-responsible for the enhanced detoxification of insecticides. Spatial expression studies revealed these up-regulated genes to be abundantly distributed in fat bodies and genetically mapped on autosome 2 or 3 of house flies, and their expression could be regulated by factors on autosome 1, 2 and 5. Taken together, these results demonstrate that multiple carboxylesterase genes are co-upregulated in resistant house flies, providing further evidence for their involvement in the detoxification of insecticides and development of insecticide resistance.
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      PubDate: 2017-11-16T13:53:32Z
      DOI: 10.1016/j.ibmb.2017.11.007
  • Inhibition of the complement system by saliva of Anopheles (Nyssorhynchus)
    • Authors: Antonio Ferreira Mendes-Sousa; Vladimir Fazito Vale; Daniel Costa Queiroz; Adalberto Alves Pereira-Filho; Naylene Carvalho Sales da Silva; Leonardo Barbosa Koerich; Luciano Andrade Moreira; Marcos Horácio Pereira; Maurício Roberto Sant’Anna; Ricardo Nascimento Araújo; John Andersen; Jesus Gilberto Valenzuela; Nelder Figueiredo Gontijo
      Abstract: Publication date: Available online 8 November 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Antonio Ferreira Mendes-Sousa, Vladimir Fazito Vale, Daniel Costa Queiroz, Adalberto Alves Pereira-Filho, Naylene Carvalho Sales da Silva, Leonardo Barbosa Koerich, Luciano Andrade Moreira, Marcos Horácio Pereira, Maurício Roberto Sant’Anna, Ricardo Nascimento Araújo, John Andersen, Jesus Gilberto Valenzuela, Nelder Figueiredo Gontijo
      Anopheline mosquitoes are vectors of malaria parasites. Their saliva contains anti-hemostatic and immune-modulator molecules that favor blood feeding and parasite transmission. In this study, we describe the inhibition of the alternative pathway of the complement system (AP) by Anopheles aquasalis salivary gland extracts (SGE). According to our results, the inhibitor present in SGE acts on the initial step of the AP blocking deposition of C3b on the activation surfaces. Properdin, which is a positive regulatory molecule of the AP, binds to SGE. When SGE was treated with an excess of properdin, it was unable to inhibit the AP. Through SDS-PAGE analysis, A. aquasalis presented a salivary protein with the same molecular weight as recombinant complement inhibitors belonging to the SG7 family described in the saliva of other anopheline species. At least some SG7 proteins bind to properdin and are AP inhibitors. Searching for SG7 proteins in the A. aquasalis genome, we retrieved a salivary protein that shared an 85% identity with albicin, which is the salivary alternative pathway inhibitor from A. albimanus. This A. aquasalis sequence was also very similar (81% ID) to the SG7 protein from A. darlingi, which is also an AP inhibitor. Our results suggest that the salivary complement inhibitor from A. aquasalis is an SG7 protein that can inhibit the AP by binding to properdin and abrogating its stabilizing activity. Albicin, which is the SG7 from A. albimanus, can directly inhibit AP convertase. Given the high similarity of SG7 proteins, the SG7 from A. aquasalis may also directly inhibit AP convertase in the absence of properdin.
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      PubDate: 2017-11-09T11:48:23Z
      DOI: 10.1016/j.ibmb.2017.11.004
  • Nuclear receptor HR3 controls locust molt by regulating chitin synthesis
           and degradation genes of Locusta migratoria
    • Authors: Xiaoming Zhao; Zhongyu Qin; Weimin Liu; Xiaojian Liu; Bernard Moussian; Enbo Ma; Sheng Li; Jianzhen Zhang
      Abstract: Publication date: Available online 4 November 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Xiaoming Zhao, Zhongyu Qin, Weimin Liu, Xiaojian Liu, Bernard Moussian, Enbo Ma, Sheng Li, Jianzhen Zhang
      During growth and development of insects, the steroid hormone 20-Hydroxyecdysone (20E) regulates the molting process through activation of a series of genes including E74, E75 and HR3 by the 20E receptor EcR. Here, we analyzed the function of LmHR3 in the migratory locust Locusta migratoria. By sequence comparison, we first identified and characterized the putative nuclear receptor protein (LmHR3) based on L. migratoria transcriptome data. The full length cDNA is 2272 bp long encoding a protein of 455 amino acids that contains a DNA binding domain (zinc finger) and a ligand binding domain. Phylogenetic analyses showed that LmHR3 has a high homology with the ortholog from Blattaria. RT-qPCR results revealed that LmHR3 has a low level expression in the early days of 5th instar nymphs, and then increases and peaks at day 6, followed by a decrease to low levels before ecdysis. The LmHR3, hence, coincides with the profile of circulating 20E levels. Indeed, we show that transcription of LmHR3 is induced by 20E in vivo, and significantly suppressed by successfully knocking down expression of LmEcR. After injection of dsRNA for LmHR3 (dsLmHR3) at day 2 of earlier instar nymphs (3rd and 4th instar) and final instar nymphs (5th instar), none of the nymphs were able to molt normally, and eventually died. Chitin staining and ultra-structural analysis showed that both the synthesis of the new cuticle and the degradation of the old cuticle were blocked in the dsLmHR3 treated nymphs. Especially, chitin synthesis genes (LmUAP1 and LmCHS1) and chitinase genes (LmCHT5 and LmCHT10) were significantly down-regulated in the dsLmHR3 treatment group. Together, our results suggest that LmHR3 is involved in the control of chitin synthesis and degradation during L. migratoria molting.
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      PubDate: 2017-11-09T11:48:23Z
      DOI: 10.1016/j.ibmb.2017.11.001
  • The role of a single gene encoding the Single von Willebrand factor
           C-domain protein (SVC) in bumblebee immunity extends beyond antiviral
    • Authors: Haidong Wang; Guy Smagghe; Ivan Meeus
      Abstract: Publication date: Available online 23 October 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Haidong Wang, Guy Smagghe, Ivan Meeus
      The Single von Willebrand factor C-domain proteins (SVCs) are a group of short proteins mainly found in arthropods. They are proposed to be responsive in relation to environmental challenges including the nutritional status, bacterial and viral infections. The SVC protein Vago acts as a cross-talk molecule between the small interfering RNA (siRNA) pathway and the Jak/STAT pathway upon viral infection in Drosophila melanogaster and Culex mosquito cells. Unlike flies and mosquitoes that possess diverse SVCs, most bee species only have one of which the function remains unclear. Here we investigated whether this single SVC within the genome of the bumblebee Bombus terrestris is also involved in the host antiviral immunity and whether links with other immune pathways can be found. We can show the presence of two key characteristics of Vago linked with BtSVC in bumblebees. The antiviral character is proven by silencing BtSVC, which lead to increased Israeli acute paralysis virus (IAPV) levels in the fat body. Second, the silencing of BtDicer-2 resulted in a lower expression of BtSVC and increased IAPV levels, confirming the link between Dicer-2 and BtSVC. We were, however, unable to demonstrate a third known role of Vago in the activation of the Jak/STAT pathway. This is probably because we lack good markers for this pathway in bumblebees. Interestingly, we found that BtSVC contributes to the basal expression levels of four antimicrobial peptide (AMP)-coding genes in the fat body of the bumblebees. Therefore, the single SVC gene in bumblebees may be involved in both host antiviral immunity and basal AMPs expression.
      Graphical abstract image

      PubDate: 2017-10-26T05:16:53Z
      DOI: 10.1016/j.ibmb.2017.10.002
  • Describing the role of Drosophila melanogaster ABC transporters in
           insecticide biology using CRISPR-Cas9 knockouts
    • Authors: Shane Denecke; Roberto Fusetto; Philip Batterham
      Abstract: Publication date: Available online 20 October 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Shane Denecke, Roberto Fusetto, Philip Batterham
      ABC transporters have a well-established role in drug resistance, effluxing xenobiotics from cells and tissues within the organism. More recently, research has been dedicated to understanding the role insect ABC transporters play in insecticide toxicity, but progress in understanding the contribution of specific transporters has been hampered by the lack of functional genetic tools. Here, we report knockouts of three Drosophila melanogaster ABC transporter genes, Mdr49, Mdr50, and Mdr65, that are homologous to the well-studied mammalian ABCB1 (P-glycoprotein). Each knockout mutant was created in the same wild type background and tested against a panel of insecticides representing different chemical classes. Mdr65 knockouts were more susceptible to all neuroactive insecticides tested, but Mdr49 and Mdr50 knockouts showed increased susceptibility or resistance depending on the insecticide used. Mdr65 was chosen for further analysis. Calculation of LC50 values for the Mdr65 knockout allowed the substrate specificity of this transporter to be examined. No obvious distinguishing structural features were shared among MDR65 substrates. A role for Mdr65 in insecticide transport was confirmed by testing the capacity of the knockout to synergize with the ABC inhibitor verapamil and by measuring the levels of insecticide retained in the body of knockout flies. These data unambiguously establish the influence of ABC transporters on the capacity of wild type D. melanogaster to tolerate insecticide exposure and suggest that both tissue and substrate specificity underpin this capacity.
      Graphical abstract image

      PubDate: 2017-10-26T05:16:53Z
      DOI: 10.1016/j.ibmb.2017.09.017
  • Biochemical identification of residues that discriminate between
           3,4-dihydroxyphenylalanine decarboxylase and
           3,4-dihydroxyphenylacetaldehyde synthase-mediated reactions
    • Authors: Jing Liang; Haizhen Ding; Qian Han; Jianyong Li
      Abstract: Publication date: Available online 14 October 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Jing Liang, Haizhen Ding, Qian Han, Jianyong Li
      In available insect genomes, there are several L-3,4-dihydroxyphenylalanine (L-dopa) decarboxylase (DDC)-like or aromatic amino acid decarboxylase (AAAD) sequences. This contrasts to those of mammals whose genomes contain only one DDC. Our previous experiments established that two DDC-like proteins from Drosophila actually mediate a complicated decarboxylation-oxidative deamination process of dopa in the presence of oxygen, leading to the formation of 3,4-dihydroxyphenylacetaldehyde (DHPA), CO2, NH3, and H2O2. This contrasts to the typical DDC-catalyzed reaction, which produces CO2 and dopamine. These DDC-like proteins were arbitrarily named DHPA synthases based on their critical role in insect soft cuticle formation. Establishment of reactions catalyzed by these AAAD-like proteins solved a puzzle that perplexed researchers for years, but to tell a true DHPA synthase from a DDC in the insect AAAD family remains problematic due to high sequence similarity. In this study, we performed extensive structural and biochemical comparisons between DHPA synthase and DDC. These comparisons identified several target residues potentially dictating DDC-catalyzed and DHPA synthase-catalyzed reactions, respectively. Comparison of DHPA synthase homology models with crystal structures of typical DDC proteins, particularly residues in the active sites, provided further insights for the roles these identified target residues play. Subsequent site-directed mutagenesis of the tentative target residues and activity evaluations of their corresponding mutants determined that active site His192 and Asn192 are essential signature residues for DDC- and DHPA synthase-catalyzed reactions, respectively. Oxygen is required in DHPA synthase-mediated process and this oxidizing agent is reduced to H2O2 in the process. Biochemical assessment established that H2O2, formed in DHPA synthase-mediated process, can be reused as oxidizing agent and this active oxygen species is reduced to H2O; thereby avoiding oxidative stress by H2O2. Results of our structural and functional analyses provide a reasonable explanation of mechanisms involved in DHPA synthase-mediated reactions. Based on the key active site residue Asn192, identified in Drosophila DHPA synthase, we were able to distinguish all available insect DHPA synthases from DDC sequences primarily.
      Graphical abstract image

      PubDate: 2017-10-14T08:17:32Z
      DOI: 10.1016/j.ibmb.2017.10.001
  • Accumulation of dsRNA in endosomes contributes to inefficient RNA
           interference in the fall armyworm, Spodoptera frugiperda
    • Authors: June-Sun Yoon; Dhandapani Gurusamy; Subba Reddy Palli
      Abstract: Publication date: Available online 23 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): June-Sun Yoon, Dhandapani Gurusamy, Subba Reddy Palli
      RNA interference (RNAi) efficiency varies among insects studied. The barriers for successful RNAi include the presence of double-stranded ribonucleases (dsRNase) in the lumen and hemolymph that could potentially digest double-stranded RNA (dsRNA) and the variability in the transport of dsRNA into and within the cells. We recently showed that the dsRNAs are transported into lepidopteran cells, but they are not processed into small interference RNAs (siRNAs) because they are trapped in acidic bodies. In the current study, we focused on the identification of acidic bodies in which dsRNAs accumulate in Sf9 cells. Time-lapse imaging studies showed that dsRNAs enter Sf9 cells and accumulate in acidic bodies within 20 min after their addition to the medium. CypHer-5E-labeled dsRNA also accumulated in the midgut and fat body dissected from Spodoptera frugiperda larvae with similar patterns observed in Sf9 cells. Pharmacological inhibitor assays showed that the dsRNAs use clathrin receptor-mediated endocytosis pathway for transport into the cells. We investigated the potential dsRNA accumulation sites employing LysoTracker and double labeling experiments using the constructs to express a fusion of green fluorescence protein with early or late endosomal marker proteins and CypHer-5E-labeled dsRNA. Interestingly, CypHer-5E-labeled dsRNA accumulated predominantly in early and late endosomes. These data suggest that entrapment of internalized dsRNA in endosomes is one of the major factors contributing to inefficient RNAi response in lepidopteran insects.
      Graphical abstract image

      PubDate: 2017-09-27T08:57:22Z
      DOI: 10.1016/j.ibmb.2017.09.011
  • Cap n collar transcription factor regulates multiple genes coding for
           proteins involved in insecticide detoxification in the red flour beetle,
           Tribolium castaneum
    • Authors: Megha Kalsi; Subba Reddy Palli
      Abstract: Publication date: Available online 23 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Megha Kalsi, Subba Reddy Palli
      In invertebrates, a heterodimer of xenobiotic transcription factors, cap n collar C isoform (CncC) and muscle aponeurosis fibromatosis (Maf) mediate cellular defense. In insects, these proteins regulate expression of genes involved in insecticide detoxification. In the current study, we performed sequencing of cDNA copied from RNA isolated from Tribolium castaneum pyrethroid resistant strain (QTC279) beetles injected with CncC or green fluorescence protein (GFP, control) dsRNA. Differential expression analysis of sequences identified 662 genes that showed a decrease and 91 genes that showed an increase in expression (p value ≤ 0.01 and log2 fold change of ≥ 1.5) in CncC knockdown insects when compared to their expression in control insects. We selected a subset of 27 downregulated genes and verified their differential expression using qRT-PCR. This subset of 27 genes included 21 genes with a predicted function in xenobiotic detoxification. RNAi and insecticide bioassays were employed to study the function of six of these genes coding for CYP4G7, CYP4G14, GST-1 and four ABC transporters, ABCA-UB, ABCA-A1 and ABCA-A1L and ABCA-9B involved in all three phases of insecticide detoxification. These data suggest that CncC regulates genes coding for proteins involved in detoxification of insecticides.
      Graphical abstract image

      PubDate: 2017-09-27T08:57:22Z
      DOI: 10.1016/j.ibmb.2017.09.009
  • The microRNA ame-miR-279a regulates sucrose responsiveness of forager
           honey bees (Apis mellifera)
    • Authors: Fang Liu; Tengfei Shi; Wei Yin; Xin Su; Lei Qi; Zachary Y. Huang; Shaowu Zhang; Linsheng Yu
      Abstract: Publication date: Available online 20 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Fang Liu, Tengfei Shi, Wei Yin, Xin Su, Lei Qi, Zachary Y. Huang, Shaowu Zhang, Linsheng Yu
      Increasing evidence demonstrates that microRNAs (miRNA) play an important role in the regulation of animal behaviours. Honey bees (Apis mellifera) are eusocial insects, with honey bee workers displaying age-dependent behavioural maturation. Many different miRNAs have been implicated in the change of behaviours in honey bees and ame-miR-279a was previously shown to be more highly expressed in nurse bee heads than in those of foragers. However, it was not clear whether this difference in expression was associated with age or task performance. Here we show that ame-miR-279a shows significantly higher expression in the brains of nurse bees relative to forager bees regardless of their ages, and that ame-miR-279a is primarily localized in the Kenyon cells of the mushroom body in both foragers and nurses. Overexpression of ame-miR-279a attenuates the sucrose responsiveness of foragers, while its absence enhances their sucrose responsiveness. Lastly, we determined that ame-miR-279a directly target the mRNA of Mblk-1. These findings suggest that ame-miR-279a plays important roles in regulating honey bee division of labour.
      Graphical abstract image

      PubDate: 2017-09-27T08:57:22Z
      DOI: 10.1016/j.ibmb.2017.09.008
  • Maternal provision of transformer-2 is required for female development and
           embryo viability in the wasp Nasonia vitripennis
    • Authors: Elzemiek Geuverink; Anna H. Rensink; Inge Rondeel; Leo W. Beukeboom; Louis van de Zande; Eveline C. Verhulst
      Abstract: Publication date: Available online 18 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Elzemiek Geuverink, Anna H. Rensink, Inge Rondeel, Leo W. Beukeboom, Louis van de Zande, Eveline C. Verhulst
      In insect sex determination a primary signal starts the genetic sex determination cascade that, in most insect orders, is subsequently transduced down the cascade by a transformer (tra) ortholog. Only a female-specifically spliced tra mRNA yields a functional TRA-protein that forms a complex with TRA2, encoded by a transformer-2 (tra2) ortholog, to act as a sex specific splicing regulator of the downstream transcription factors doublesex (dsx) and fruitless (fru). Here, we identify the tra2 ortholog of the haplodiploid parasitoid wasp N. vitripennis (Nv-tra2) and confirm its function in N. vitripennis sex determination. Knock down of Nv-tra2 by parental RNA interference (pRNAi) results in complete sex reversal of diploid offspring from female to male, indicating the requirement of Nv-tra2 for female sex determination. As Nv-tra2 pRNAi leads to frequent lethality in early developmental stages, maternal provision of Nv-tra2 transcripts is apparently also required for another, non-sex determining function during embryogenesis. In addition, lethality following Nv-tra2 pRNAi appears more pronounced in diploid than in haploid offspring. This diploid lethal effect was also observed following Nv-tra pRNAi, which served as a positive control in our experiments. As diploid embryos from fertilized eggs have a paternal chromosome set in addition to the maternal one, this suggests that either the presence of this paternal chromosome set or the dosage effect resulting from the diploid state is incompatible with the induced male development in N. vitripennis caused by either Nv-tra2 or Nv-tra pRNAi. The role of Nv-tra2 in activating the female sex determination pathway yields more insight into the sex determination mechanism of Nasonia.
      Graphical abstract image

      PubDate: 2017-09-20T02:58:32Z
      DOI: 10.1016/j.ibmb.2017.09.007
  • Adipokinetic hormone receptor gene identification and its role in
           triacylglycerol mobilization and sexual behavior in the oriental fruit fly
           (Bactrocera dorsalis)
    • Authors: Qiu-Li Hou; Er-Hu Chen; Hong-Bo Jiang; Dan-Dan Wei; Shun-Hua Gui; Jin-Jun Wang; Guy Smagghe
      Abstract: Publication date: Available online 15 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Qiu-Li Hou, Er-Hu Chen, Hong-Bo Jiang, Dan-Dan Wei, Shun-Hua Gui, Jin-Jun Wang, Guy Smagghe
      Energy homeostasis requires continuous compensation for fluctuations in energy expenditure and availability of food resources. In insects, energy mobilization is under control of the adipokinetic hormone (AKH) where it is regulating the nutritional status by supporting the mobilization of lipids. In this study, we characterized the gene coding for the AKH receptor (AKHR) and investigated its function in the oriental fruit fly (Bactrocera dorsalis) that is economically one of the most important pest insects of tropical and subtropical fruit. Bacdo-AKHR is a typical G protein-coupled receptor (GPCR) and phylogenetic analysis confirmed that Bacdo-AKHR is closely related to insect AKHRs from other species. When expressed in Chinese hamster ovary (CHO) cells, Bacdo-AKHR exhibited a high sensitivity and selectivity for AKH peptide (EC50 = 19.3 nM). Using qPCR, the developmental stage and tissue-specific expression profiles demonstrated that Bacdo-AKHR was highly expressed in both the larval and adult stages, and also specifically in the fat body and midgut of the adult with no difference in sex. To investigate the role of AKHR in B. dorsalis, RNAi assays were performed with dsRNA against Bacdo-AKHR in adult flies of both sexes and under starvation and feeding condition. As major results, the knockdown of this gene resulted in triacylglycerol (TAG) accumulation. With RNAi-males, we observed a severe decrease in their sexual courtship activity when starved, but there was a partial rescue in copulation when refed. Also in RNAi-males, the tethered-flight duration declined compared with the control group when starved, which is confirming the dependency on energy metabolism. In RNAi-females, the sexual behavior was not affected, but their fecundity was decreased. Our findings indicate an interesting role of AKHR in the sexual behavior of males specifically. The effects are associated with TAG accumulation, and we also reported that the conserved role of AKH-mediated system in B. dorsalis is nutritional state-dependent. Hence, we provided further understanding on the multiple functions of AKH/AKHR in B. dorsalis.
      Graphical abstract image

      PubDate: 2017-09-20T02:58:32Z
      DOI: 10.1016/j.ibmb.2017.09.006
  • Recombinant expression and characterization of Lucilia cuprina CYP6G3:
           Activity and binding properties toward multiple pesticides
    • Authors: Matthew J. Traylor; Jong-Min Baek; Katelyn E. Richards; Roberto Fusetto; W. Huang; Peter Josh; Zhengzhong Chen; Padma Bollapragada; Richard A.J. O'Hair; Philip Batterham; Elizabeth M.J. Gillam
      Abstract: Publication date: Available online 14 September 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Matthew J. Traylor, Jong-Min Baek, Katelyn E. Richards, Roberto Fusetto, W. Huang, Peter Josh, Zhengzhong Chen, Padma Bollapragada, Richard A.J. O'Hair, Philip Batterham, Elizabeth M.J. Gillam
      The Australian sheep blowfly, Lucilia cuprina, is a primary cause of sheep flystrike and a major agricultural pest. Cytochrome P450 enzymes have been implicated in the resistance of L. cuprina to several classes of insecticides. In particular, CYP6G3 is a L. cuprina homologue of Drosophila melanogaster CYP6G1, a P450 known to confer multi-pesticide resistance. To investigate the basis of resistance, a bicistronic Escherichia coli expression system was developed to co-express active L. cuprina CYP6G3 and house fly (Musca domestica) P450 reductase. Recombinant CYP6G3 showed activity towards the high-throughput screening substrates, 7-ethoxycoumarin and p-nitroanisole, but not towards p-nitrophenol, coumarin, 7-benzyloxyresorufin, or seven different luciferin derivatives (P450-Glo™ substrates). The addition of house fly cytochrome b 5 enhanced the kcat for p-nitroanisole dealkylation approximately two fold (17.8 ± 0.5 vs 9.6 ± 0.2 min−1) with little effect on KM (13 ± 1 vs 10 ± 1 μM). Inhibition studies and difference spectroscopy revealed that the organochlorine compounds, DDT and endosulfan, and the organophosphate pesticides, malathion and chlorfenvinphos, bind to the active site of CYP6G3. All four pesticides showed type I binding spectra with spectral dissociation constants in the micromolar range suggesting that they may be substrates of CYP6G3. While no significant inhibition was seen with the organophosphate, diazinon, or the neonicotinoid, imidacloprid, diazinon showed weak binding in spectral assays, with a Kd value of 23 ± 3 μM CYP6G3 metabolised diazinon to the diazoxon and hydroxydiazinon metabolites and imidacloprid to the 5-hydroxy and olefin metabolites, consistent with a proposed role of CYP6G enzymes in metabolism of phosphorothioate and neonicotinoid insecticides in other species.
      Graphical abstract image

      PubDate: 2017-09-14T11:48:29Z
      DOI: 10.1016/j.ibmb.2017.09.004
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