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BIOCHEMISTRY (235 journals)                  1 2 | Last

Showing 1 - 200 of 235 Journals sorted alphabetically
AAPS PharmSciTech     Hybrid Journal   (Followers: 6)
Acetic Acid Bacteria     Open Access   (Followers: 2)
ACS Central Science     Open Access   (Followers: 6)
ACS Chemical Biology     Full-text available via subscription   (Followers: 244)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 17)
Acta Crystallographica Section D : Biological Crystallography     Hybrid Journal   (Followers: 8)
Acta Crystallographica Section F: Structural Biology Communications     Hybrid Journal   (Followers: 7)
Advances and Applications in Bioinformatics and Chemistry     Open Access   (Followers: 9)
Advances in Biological Chemistry     Open Access   (Followers: 7)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 8)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19)
African Journal of Biochemistry Research     Open Access   (Followers: 1)
African Journal of Chemical Education     Open Access   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
American Journal of Biochemistry     Open Access   (Followers: 8)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 67)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 14)
American Journal of Polymer Science     Open Access   (Followers: 25)
Amino Acids     Hybrid Journal   (Followers: 8)
Analytical Biochemistry     Hybrid Journal   (Followers: 162)
Angiogenesis     Hybrid Journal   (Followers: 3)
Annals of Clinical Biochemistry     Hybrid Journal   (Followers: 7)
Annual Review of Biochemistry     Full-text available via subscription   (Followers: 56)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 13)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 44)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 17)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Archives of Biochemistry and Biophysics     Hybrid Journal   (Followers: 20)
Archives of Insect Biochemistry and Physiology     Hybrid Journal  
Archives Of Physiology And Biochemistry     Hybrid Journal   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Avicenna Journal of Medical Biochemistry     Open Access  
Bangladesh Journal of Medical Biochemistry     Open Access   (Followers: 2)
BBA Clinical     Open Access  
BBR : Biochemistry and Biotechnology Reports     Open Access   (Followers: 4)
Biocatalysis     Open Access  
Biochemical and Biophysical Research Communications     Hybrid Journal   (Followers: 21)
Biochemical and Molecular Medicine     Full-text available via subscription   (Followers: 4)
Biochemical Compounds     Open Access  
Biochemical Engineering Journal     Hybrid Journal   (Followers: 14)
Biochemical Genetics     Hybrid Journal   (Followers: 3)
Biochemical Journal     Full-text available via subscription   (Followers: 25)
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: 289)
Biochemistry & Pharmacology : Open Access     Open Access   (Followers: 3)
Biochemistry & Physiology : Open Access     Open Access  
Biochemistry (Moscow)     Hybrid Journal   (Followers: 4)
Biochemistry (Moscow) Supplement Series A: Membrane and Cell Biology     Hybrid Journal   (Followers: 3)
Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry     Hybrid Journal   (Followers: 3)
Biochemistry and Biophysics Reports     Open Access  
Biochemistry and Cell Biology     Hybrid Journal   (Followers: 14)
Biochemistry and Molecular Biology Education     Hybrid Journal   (Followers: 6)
Biochemistry and Molecular Biology of Fishes     Full-text available via subscription   (Followers: 1)
Biochemistry Research International     Open Access   (Followers: 6)
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids     Hybrid Journal   (Followers: 7)
Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease     Hybrid Journal   (Followers: 14)
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research     Hybrid Journal   (Followers: 9)
Biochimie     Hybrid Journal   (Followers: 7)
Biochimie Open     Open Access  
Bioconjugate Chemistry     Full-text available via subscription   (Followers: 29)
BioDrugs     Full-text available via subscription   (Followers: 7)
Bioelectrochemistry     Hybrid Journal   (Followers: 2)
Biofuels     Hybrid Journal   (Followers: 10)
Biogeochemistry     Hybrid Journal   (Followers: 14)
BioInorganic Reaction Mechanisms     Hybrid Journal   (Followers: 1)
Biokemistri     Open Access  
Biological Chemistry     Partially Free   (Followers: 22)
Biomaterials Research     Open Access   (Followers: 4)
Biomedicines     Open Access   (Followers: 1)
BioMolecular Concepts     Hybrid Journal   (Followers: 2)
Bioscience, Biotechnology, and Biochemistry     Hybrid Journal   (Followers: 24)
Biosimilars     Open Access   (Followers: 1)
Biotechnology and Applied Biochemistry     Hybrid Journal   (Followers: 45)
Bitácora Digital     Open Access  
BMC Biochemistry     Open Access   (Followers: 14)
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca : Food Science and Technology     Open Access  
Carbohydrate Polymers     Hybrid Journal   (Followers: 8)
Cell Biochemistry and Biophysics     Hybrid Journal   (Followers: 6)
Cell Biochemistry and Function     Hybrid Journal   (Followers: 6)
Cellular Physiology and Biochemistry     Open Access   (Followers: 3)
ChemBioChem     Hybrid Journal   (Followers: 6)
Chemical and Biological Technologies for Agriculture     Open Access  
Chemical Biology & Drug Design     Hybrid Journal   (Followers: 20)
Chemical Engineering Journal     Hybrid Journal   (Followers: 41)
Chemical Senses     Hybrid Journal   (Followers: 1)
Chemical Speciation and Bioavailability     Open Access   (Followers: 1)
Chemico-Biological Interactions     Hybrid Journal   (Followers: 3)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 6)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry and Ecology     Hybrid Journal  
ChemTexts     Hybrid Journal  
Clinica Chimica Acta     Hybrid Journal   (Followers: 33)
Clinical Biochemist Reviews     Full-text available via subscription   (Followers: 1)
Clinical Biochemistry     Hybrid Journal   (Followers: 18)
Clinical Chemistry     Full-text available via subscription   (Followers: 66)
Clinical Chemistry and Laboratory Medicine     Hybrid Journal   (Followers: 59)
Clinical Lipidology     Full-text available via subscription   (Followers: 1)
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology     Hybrid Journal   (Followers: 5)
Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 2)
Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology     Hybrid Journal   (Followers: 8)
Comparative Biochemistry and Physiology Part D: Genomics and Proteomics     Hybrid Journal   (Followers: 3)
Comprehensive Biochemistry     Full-text available via subscription   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Current Chemical Biology     Hybrid Journal   (Followers: 2)
Current Medicinal Chemistry     Hybrid Journal   (Followers: 16)
Current Opinion in Chemical Biology     Hybrid Journal   (Followers: 27)
Current Opinion in Lipidology     Hybrid Journal   (Followers: 6)
DNA Barcodes     Open Access  
Doklady Biochemistry and Biophysics     Hybrid Journal   (Followers: 1)
Doklady Chemistry     Hybrid Journal  
Egyptian Journal of Biochemistry and Molecular Biology     Full-text available via subscription  
FABICIB     Open Access  
FEBS Letters     Hybrid Journal   (Followers: 56)
FEBS Open Bio     Open Access   (Followers: 3)
Fish Physiology and Biochemistry     Hybrid Journal   (Followers: 4)
Food & Function     Full-text available via subscription   (Followers: 5)
Foundations of Modern Biochemistry     Full-text available via subscription  
Free Radicals and Antioxidants     Full-text available via subscription   (Followers: 4)
Frontiers in Molecular Biosciences     Open Access   (Followers: 2)
Frontiers in Natural Product Chemistry     Hybrid Journal  
Global Biogeochemical Cycles     Full-text available via subscription   (Followers: 15)
Green Chemistry     Full-text available via subscription   (Followers: 10)
Histochemistry and Cell Biology     Hybrid Journal   (Followers: 5)
Indian Journal of Biochemistry and Biophysics (IJBB)     Open Access   (Followers: 3)
Indian Journal of Clinical Biochemistry     Hybrid Journal   (Followers: 1)
Indonesian Biomedical Journal     Open Access  
Insect Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 3)
International Journal of Biochemistry & Cell Biology     Hybrid Journal   (Followers: 8)
International Journal of Biochemistry and Biophysics     Open Access   (Followers: 1)
International Journal of Biological Chemistry     Open Access   (Followers: 4)
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 6)
International Journal of Food Contamination     Open Access  
International Journal of Plant Physiology and Biochemistry     Open Access   (Followers: 1)
International Journal of Plant Research     Open Access   (Followers: 3)
International Journal of Secondary Metabolite     Open Access   (Followers: 1)
Invertebrate Immunity     Open Access   (Followers: 1)
JBIC Journal of Biological Inorganic Chemistry     Hybrid Journal   (Followers: 4)
Journal of Microbial & Biochemical Technology     Open Access   (Followers: 2)
Journal of Applied Biology & Biotechnology     Open Access   (Followers: 2)
Journal of Bioactive and Compatible Polymers     Hybrid Journal   (Followers: 2)
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: 191)
Journal of Biomaterials Science, Polymer Edition     Hybrid Journal   (Followers: 9)
Journal of Carbohydrate Chemistry     Hybrid Journal   (Followers: 7)
Journal of Cellular Biochemistry     Hybrid Journal   (Followers: 5)
Journal of Chemical Biology     Hybrid Journal   (Followers: 2)
Journal of Chemical Neuroanatomy     Hybrid Journal  
Journal of Clinical Lipidology     Hybrid Journal   (Followers: 1)
Journal of Comparative Physiology B : Biochemical, Systemic, and Environmental Physiology     Hybrid Journal   (Followers: 4)
Journal of Drug Discovery and Therapeutics     Open Access  
Journal of Enzyme Inhibition and Medicinal Chemistry     Hybrid Journal   (Followers: 3)
Journal of Evolutionary Biochemistry and Physiology     Hybrid Journal  
Journal of Food and Drug Analysis     Open Access  
Journal of Forensic Toxicology and Pharmacology     Hybrid Journal   (Followers: 4)
Journal of Inborn Errors of Metabolism and Screening     Open Access  
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 6)
Journal of Medical and Biomedical Sciences     Open Access  
Journal of Medical Biochemistry     Open Access   (Followers: 4)
Journal of Medicine and Biomedical Research     Open Access   (Followers: 1)
Journal of Molecular Biochemistry     Open Access   (Followers: 3)
Journal of Molecular Diagnostics     Hybrid Journal   (Followers: 6)
Journal of Neurochemistry     Hybrid Journal   (Followers: 3)
Journal of Nutritional Biochemistry     Hybrid Journal   (Followers: 7)
Journal of Pediatric Biochemistry     Hybrid Journal   (Followers: 1)
Journal of Peptide Science     Hybrid Journal   (Followers: 22)
Journal of Photochemistry and Photobiology B: Biology     Hybrid Journal   (Followers: 3)
Journal of Physiobiochemical Metabolism     Hybrid Journal   (Followers: 1)
Journal of Physiology and Biochemistry     Hybrid Journal   (Followers: 3)
Journal of Plant Biochemistry and Biotechnology     Hybrid Journal   (Followers: 6)
Journal of Steroid Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 2)
Journal of Virology & Antiviral Research     Hybrid Journal   (Followers: 5)
Journal of Wood Chemistry and Technology     Hybrid Journal   (Followers: 8)
La Rivista Italiana della Medicina di Laboratorio - Italian Journal of Laboratory Medicine     Hybrid Journal  
Lab on a Chip     Full-text available via subscription   (Followers: 35)
Marine Chemistry     Hybrid Journal   (Followers: 6)
Methods in Enzymology     Full-text available via subscription   (Followers: 11)
Molecular and Biochemical Parasitology     Hybrid Journal   (Followers: 2)
Molecular and Cellular Biochemistry     Hybrid Journal   (Followers: 6)
Molecular Aspects of Medicine     Hybrid Journal   (Followers: 3)
Molecular Informatics     Hybrid Journal   (Followers: 6)
Molecular inhibitors in targeted therapy     Open Access  
Moscow University Chemistry Bulletin     Hybrid Journal   (Followers: 1)
Mycologia     Hybrid Journal  
Mycology : An International Journal on Fungal Biology     Hybrid Journal   (Followers: 5)
Natural Products and Bioprospecting     Open Access   (Followers: 2)
Nature Chemical Biology     Full-text available via subscription   (Followers: 72)
Nature Communications     Open Access   (Followers: 176)
Neurosignals     Open Access  
NOVA     Open Access  
Novelty in Biomedicine     Open Access  
OA Biochemistry     Open Access   (Followers: 1)
OA Inflammation     Open Access  
Ocean Acidification     Open Access   (Followers: 3)
Organic & Biomolecular Chemistry     Full-text available via subscription   (Followers: 89)
Peptidomics     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  [3043 journals]
  • FOXA transcriptional factor modulates insect susceptibility to Bacillus
           thuringiensis Cry1Ac toxin by regulating the expression of toxin-receptor
           ABCC2 and ABCC3 genes
    • Authors: Jianghuai Li; Yuemin Ma; Wanli Yuan; Yutao Xiao; Chenxi Liu; Jia Wang; Jianxin Peng; Rong Peng; Mario Soberón; Alejandra Bravo; Yongbo Yang; Kaiyu Liu
      Pages: 1 - 11
      Abstract: Publication date: Available online 21 July 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Jianghuai Li, Yuemin Ma, Wanli Yuan, Yutao Xiao, Chenxi Liu, Jia Wang, Jianxin Peng, Rong Peng, Mario Soberón, Alejandra Bravo, Yongbo Yang, Kaiyu Liu
      Cry toxins produced by Bacillus thuringiensis (Bt) are insecticidal proteins widely used in insect control. Recently, it was shown that ATP-binding cassette transporter proteins (ABC) such as ABCC2, ABCC3, ABCG1 and ABCA2 are implicated in the insecticidal action of Cry toxins as putative receptors. However, the transcriptional regulators involved in the expression of ABC transporter genes remain unknown. Sequence analysis of promoter regions of ABCC2 gene from Helicoverpa armigera and ABCC3 gene from Spodoptera litura Sl-HP cultured cells, revealed the potential participation of Forkhead box protein A (FOXA), a transcription factor that regulates the expression of genes through remodeling chromatin. To determine if FOXA was involved in regulating expression of ABCC2 and ABCC3 genes, the expression of FOXA, ABCC2 and ABCC3 was compared in Sl-HP cells that are sensitive to Cry1Ac toxin with those on S. frugiperda Sf9 cells that are not sensitive to the toxin. Expression levels of those genes were significantly higher in Sl-HP than in Sf9 cells. Transient expression of FOXA in Sf9 cells activated ABCC2 and ABCC3 transcription, which directly correlated with enhanced Cry1Ac-susceptibility in these cells. Silencing of FOXA gene expression by RNAi in H. armigera larvae resulted in a decreased expression of ABCC2 and ABCC3 without affecting expression of other Cry toxin receptor genes such as alkaline phosphatase, aminopeptidase or cadherin. Silencing of FOXA gene expression also resulted in a Cry1Ac-tolerant phenotype since lower mortality and higher pupation rate were observed in diet containing Cry1Ac protoxin in comparison with the control group. These results demonstrate that FOXA up-regulates expression of the Cry1Ac-toxin receptor ABCC2 and ABCC3 genes, and that lower FOXA expression correlates with tolerance to Cry toxin in cell lines and in lepidopteran larvae.
      Graphical abstract image

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

      PubDate: 2017-07-01T03:03:53Z
      DOI: 10.1016/j.ibmb.2017.06.010
      Issue No: Vol. 87 (2017)
  • nanos-Driven expression of piggyBac transposase induces mobilization of a
           synthetic autonomous transposon in the malaria vector mosquito, Anopheles
    • Authors: Vanessa M. Macias; Alyssa J. Jimenez; Bianca Burini-Kojin; David Pledger; Nijole Jasinskiene; Celine Hien Phong; Karen Chu; Aniko Fazekas; Kelcie Martin; Osvaldo Marinotti; Anthony A. James
      Pages: 81 - 89
      Abstract: Publication date: August 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 87
      Author(s): Vanessa M. Macias, Alyssa J. Jimenez, Bianca Burini-Kojin, David Pledger, Nijole Jasinskiene, Celine Hien Phong, Karen Chu, Aniko Fazekas, Kelcie Martin, Osvaldo Marinotti, Anthony A. James
      Transposons are a class of selfish DNA elements that can mobilize within a genome. If mobilization is accompanied by an increase in copy number (replicative transposition), the transposon may sweep through a population until it is fixed in all of its interbreeding members. This introgression has been proposed as the basis for drive systems to move genes with desirable phenotypes into target species. One such application would be to use them to move a gene conferring resistance to malaria parasites throughout a population of vector mosquitos. We assessed the feasibility of using the piggyBac transposon as a gene-drive mechanism to distribute anti-malarial transgenes in populations of the malaria vector, Anopheles stephensi. We designed synthetic gene constructs that express the piggyBac transposase in the female germline using the control DNA of the An. stephensi nanos orthologous gene linked to marker genes to monitor inheritance. Two remobilization events were observed with a frequency of one every 23 generations, a rate far below what would be useful to drive anti-pathogen transgenes into wild mosquito populations. We discuss the possibility of optimizing this system and the impetus to do so.
      Graphical abstract image

      PubDate: 2017-07-10T07:34:33Z
      DOI: 10.1016/j.ibmb.2017.06.014
      Issue No: Vol. 87 (2017)
  • Cry46Ab from Bacillus thuringiensis TK-E6 is a new mosquitocidal toxin
           with aerolysin-type architecture
    • Authors: Tohru Hayakawa; Akira Sakakibara; Sho Ueda; Yoshinao Azuma; Toru Ide; So Takebe
      Pages: 100 - 106
      Abstract: Publication date: August 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 87
      Author(s): Tohru Hayakawa, Akira Sakakibara, Sho Ueda, Yoshinao Azuma, Toru Ide, So Takebe
      Cry46Ab is a Cry toxin derived from Bacillus thuringiensis TK-E6. Cry46Ab is not significantly homologous to other mosquitocidal Cry or Cyt toxins and is classified as an aerolysin-type pore-forming toxin based on structural similarity. In this study, the potency of Cry46Ab was assessed for its potential application to mosquito control. A synthetic Cry46Ab gene, cry46Ab-S1, was designed to produce recombinant Cry46Ab as a glutathione-S-transferase fusion in Escherichia coli. Recombinant Cry46Ab showed apparent toxicity to Culex pipiens larvae, with a 50% lethal dose of 1.02 μg/ml. In an artificial lipid bilayer, Cry46Ab activated by trypsin caused typical current transitions between open and closed states, suggesting it functions as a pore-forming toxin similar to other Cry and Cyt toxins. The single-channel conductance was 103.3 ± 4.1 pS in 150 mM KCl. Co-administration of recombinant Cry46Ab with other mosquitocidal Cry toxins, especially the combination of Cry4Aa and Cry46Ab, resulted in significant synergistic toxicity against C. pipiens larvae. Co-administration of multiple toxins exhibiting different modes of action is believed to prevent the onset of resistance in insects. Our data, taken in consideration with the differences in its structure, suggest that Cry46Ab could be useful in not only reducing resistance levels but also improving the insecticidal activity of Bt-based bio-insecticides.
      Graphical abstract image

      PubDate: 2017-07-10T07:34:33Z
      DOI: 10.1016/j.ibmb.2017.06.015
      Issue No: Vol. 87 (2017)
  • CRISPR/Cas9 mediated genome editing of Helicoverpa armigera with mutations
           of an ABC transporter gene HaABCA2 confers resistance to Bacillus
           thuringiensis Cry2A toxins
    • Authors: Jing Wang; Huidong Wang; Shaoyan Liu; Laipan Liu; Wee Tek Tay; Thomas K. Walsh; Yihua Yang; Yidong Wu
      Pages: 147 - 153
      Abstract: Publication date: August 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 87
      Author(s): Jing Wang, Huidong Wang, Shaoyan Liu, Laipan Liu, Wee Tek Tay, Thomas K. Walsh, Yihua Yang, Yidong Wu
      High levels of resistance to Bt toxin Cry2Ab have been identified to be genetically linked with loss of function mutations of an ABC transporter gene (ABCA2) in two lepidopteran insects, Helicoverpa armigera and Helicoverpa punctigera. To further confirm the causal relationship between the ABCA2 gene (HaABCA2) and Cry2Ab resistance in H. armigera, two HaABCA2 knockout strains were created from the susceptible SCD strain with the CRISPR/Cas9 genome editing system. One strain (SCD-A2KO1) is homozygous for a 2-bp deletion in exon 2 of HaABCA2 created by non-homologous end joining (NHEJ). The other strain (SCD-A2KO2) is homozygous for a 5-bp deletion in exon 18 of HaABCA2 made by homology-directed repair (HDR), which was produced to mimic the r2 resistance allele of a field-derived Cry2Ab-resistant strain from Australia. Both knockout strains obtained high levels of resistance to both Cry2Aa (>120-fold) and Cry2Ab (>100-fold) compared with the original SCD strain, but no or very limited resistance to Cry1Ac (<4-fold). Resistance to Cry2Ab in both knockouts is recessive, and genetic complementary tests confirmed Cry2Ab resistance alleles are at the same locus (i.e. HaABCA2) for the two strains. Brush border membrane vesicles (BBMVs) of midguts from both knockout strains lost binding with Cry2Ab, but maintained the same binding with Cry1Ac as the SCD strain. In vivo functional evidence from this study demonstrates knockout of HaABCA2 confers high levels of resistance to both Cry2Aa and Cry2Ab, confirming that HaABCA2 plays a key role in mediating toxicity of both Cry2Aa and Cry2Ab against H. armigera.
      Graphical abstract image

      PubDate: 2017-07-20T02:25:55Z
      DOI: 10.1016/j.ibmb.2017.07.002
      Issue No: Vol. 87 (2017)
  • Wolbachia-induced loss of male fertility is likely related to branch chain
           amino acid biosynthesis and iLvE in Laodelphax striatellus
    • Authors: Jia-Fei Ju; Ary A. Hoffmann; Yan-Kai Zhang; Xing-Zhi Duan; Yan Guo; Jun-Tao Gong; Wen-Chao Zhu; Xiao-Yue Hong
      Pages: 11 - 20
      Abstract: Publication date: June 2017
      Source:Insect Biochemistry and Molecular Biology, Volume 85
      Author(s): Jia-Fei Ju, Ary A. Hoffmann, Yan-Kai Zhang, Xing-Zhi Duan, Yan Guo, Jun-Tao Gong, Wen-Chao Zhu, Xiao-Yue Hong
      Wolbachia are endosymbionts that infect many species of arthropods and nematodes. Wolbachia-induced cytoplasmic incompatibility (CI) is the most common phenotype in affected hosts, involving embryonic lethality in crosses between Wolbachia-infected males and uninfected females. The molecular mechanisms underlying this phenomenon are currently unclear. Here we examine the molecular correlates of the Wolbachia infection in Laodelphax striatellus (Fallén), an important rice pest, where embryonic lethality is strong and almost complete. We compared the gene expression of 4-day-old Wolbachia-infected and uninfected L. striatellus testes to identify candidate genes for paternal-effect embryonic lethality induction. Based on microarray analysis, iLvE was the most down-regulated gene; this gene mediates branched-chain amino acid (BCAA) biosynthesis and participates in many processes related to reproductive performance. After knocking down iLvE by RNAi in uninfected male L. striatellus, male fertility was reduced, leading to a decrease in embryo hatching rates, but fertility was rescued in crosses between these males and Wolbachia-infected females. Removal of BCAA in chemically-defined diets of uninfected males also led to a loss of male fertility. Low amino acid nutrition may enhance exposure time of sperm to Wolbachia in the testes to affect adult reproduction in L. striatellus by reducing the number of sperm transferred per mating by males. These results indicate that Wolbachia may decrease male fertility in L. striatellus by acting on iLvE, a key factor of BCAA biosynthesis, and delaying sperm maturation.
      Graphical abstract image

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

      PubDate: 2017-06-02T15:59:04Z
      DOI: 10.1016/j.ibmb.2017.05.003
      Issue No: Vol. 85 (2017)
  • Success in the acquisition of Bombyx mori sperm motility is influenced by
           the extracellular production of nitric oxide (NO) in the presence of
           seminal fluid nitric oxide synthetase (NOS)
    • Authors: Sumiharu Nagaoka; Maiko Asagoshi; Keita Kato; Yuki Takata
      Pages: 40 - 47
      Abstract: Publication date: Available online 13 April 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Sumiharu Nagaoka, Maiko Asagoshi, Keita Kato, Yuki Takata
      A trypsin-like protease called initiatorin is known to initiate sperm motility in the silkworm, Bombyx mori, but little is known about the signaling events leading to sperm flagellar beating. The aim of this study was to investigate whether this mechanism of sperm motility activation involves the signaling transmitter nitric oxide (NO). NO is produced from the amino acid L-arginine by the enzyme action of nitric oxide synthase (NOS; EC Simple treatment of quiescent sperm with an NO donor (SNAP or NOC7) in vitro did not lead to activation of motility. Nevertheless, initiatorin- or trypsin-induced motility was blocked by pretreatment of sperm with either the NOS inhibitor L-NAME or NO scavenger carboxy-PTIO. These observations suggested that NO may play important physiological roles in the acquisition of sperm motility under the in vitro condition used here. Then, we investigated whether NO synthesis would occur in the spermatophore, a capsule containing spermatozoa that is created by the contents of various male reproductive glands and is the site of sperm maturation. The amounts of NO2 − and NO3 −, stable metabolites of NO, reached maximum values after enclosure in the spermatophore, a time when apyrene spermatozoa acquire vigorous motility. Moreover, RT-PCR and Western blotting analyses of NOS indicated that it is abundantly expressed in glandula (g.) lacteola of the virgin male ejaculatory duct, from which it is secreted to the seminal fluid and transferred to the female during mating. Previous studies demonstrated that free L-arginine is supplied de novo by a specific proteolytic reaction in which initiatorin participates during spermatophore formation (Osanai et al., 1987c). Based on these results, it can be presumed that the mixing of seminal fluid contents from each male reproductive organ during ejaculation induced NO production outside of the spermatid, and exogenous NO stimulated a signaling pathway involved in the activation of silkworm apyrene sperm.
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      PubDate: 2017-04-18T10:38:55Z
      DOI: 10.1016/j.ibmb.2017.04.003
      Issue No: Vol. 84 (2017)
  • Mdr65 decreases toxicity of multiple insecticides in Drosophila
    • Authors: Haina Sun; Nicolas Buchon; Jeffrey G. Scott
      Abstract: Publication date: Available online 10 August 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Haina Sun, Nicolas Buchon, Jeffrey G. Scott
      ABC transporters are ubiquitous membrane-bound proteins, present in both prokaryotes and eukaryotes. The major function of eukaryotic ABC transporters is to mediate the efflux of a variety of substrates (including xenobiotics) out of cells. ABC transporters have been widely investigated in humans, particularly for their involvement in multidrug resistance (MDR). Considerably less is known about their roles in transport and/or excretion in insects. ABC transporters are only known to function as exporters in insects. Drosophila melanogaster has 56 ABC transporter genes, including eight which are phylogenetically most similar to the human Mdr genes (ABCB1 clade). We investigated the role of ABC transporters in the ABCB1 clade in modulating the susceptibility to insecticides. We took advantage of the GAL4/UAS system in D. melanogaster to knockdown the expression levels of Mdr65, Mdr50, Mdr49 and ABCB6 using transgenic UAS-RNAi lines and conditional driver lines. The most notable effects were increased sensitivities to nine different insecticides by silencing of Mdr65. Furthermore, a null mutation of Mdr65 decreased the malathion, malaoxon and fipronil LC50 values by a factor of 1.9, 2.1 and 3.9, respectively. Altogether, this data demonstrates the critical role of ABC transporters, particularly Mdr65, in altering the toxicity of specific, structurally diverse, insecticides in D. melanogaster.
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      PubDate: 2017-08-14T15:46:16Z
      DOI: 10.1016/j.ibmb.2017.08.002
  • Identification of Cry48Aa/Cry49Aa toxin ligands in the midgut of Culex
           quinquefasciatus larvae
    • Authors: Tatiana Maria Teodoro Rezende; Tatiany Patrícia Romão; Michel Batista; Colin Berry; Michael J. Adang; Maria Helena Neves Lobo Silva-Filha
      Abstract: Publication date: Available online 3 August 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Tatiana Maria Teodoro Rezende, Tatiany Patrícia Romão, Michel Batista, Colin Berry, Michael J. Adang, Maria Helena Neves Lobo Silva-Filha
      A binary mosquitocidal toxin composed of a three-domain Cry-like toxin (Cry48Aa) and a binary-like toxin (Cry49Aa) was identified in Lysinibacillus sphaericus. Cry48Aa/Cry49Aa has action on Culex quinquefasciatus larvae, in particular, to those that are resistant to the Bin Binary toxin, which is the major insecticidal factor from L. sphaericus-based biolarvicides, indicating that Cry48Aa/Cry49Aa interacts with distinct target sites in the midgut and can overcome Bin toxin resistance. This study aimed to identify Cry48Aa/Cry49Aa ligands in C. quinquefasciatus midgut through binding assays and mass spectrometry. Several proteins, mostly from 50 to 120 kDa, bound to the Cry48Aa/Cry49Aa toxin were revealed by toxin overlay and pull-down assays. These proteins were identified against the C. quinquefasciatus genome and after analysis a set of 49 proteins were selected which includes midgut bound proteins such as aminopeptidases, amylases, alkaline phosphatases in addition to molecules from other classes that can be potentially involved in this toxin's mode of action. Among these, some proteins are orthologs of Cry receptors previously identified in mosquito larvae, as candidate receptors for Cry48Aa/Cry49Aa toxin. Further investigation is needed to evaluate the specificity of their interactions and their possible role as receptors.
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      PubDate: 2017-08-04T14:31:28Z
      DOI: 10.1016/j.ibmb.2017.08.001
  • Serine protease-related proteins in the malaria mosquito, Anopheles
    • Authors: Xiaolong Cao; Mansi Gulati; Haobo Jiang
      Abstract: Publication date: Available online 2 August 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Xiaolong Cao, Mansi Gulati, Haobo Jiang
      Insect serine proteases (SPs) and serine protease homologs (SPHs) participate in digestion, defense, development, and other physiological processes. In mosquitoes, some clip-domain SPs and SPHs (i.e. CLIPs) have been investigated for possible roles in antiparasitic responses. In a recent test aimed at improving quality of gene models in the Anopheles gambiae genome using RNA-seq data, we observed various discrepancies between gene models in AgamP4.5 and corresponding sequences selected from those modeled by Cufflinks, Trinity and Bridger. Here we report a comparative analysis of the 337 SP-related proteins in A. gambiae by examining their domain structures, sequence diversity, chromosomal locations, and expression patterns. One hundred and ten CLIPs contain 1 to 5 clip domains in addition to their protease domains (PDs) or non-catalytic, protease-like domains (PLDs). They are divided into five subgroups: CLIPAs (22) are clip1−5-PLD; CLIPBs (29), CLIPCs (12) and CLIPDs (14) are mainly clip-PD; most CLIPEs (33) have a domain structure of PD/PLD-PLD-clip-PLD0−1. While expression of the CLIP genes in group-1 is generally low and detected in various tissue- and stage-specific RNA-seq libraries, some putative GPs/GPHs (i.e. single domain gut SPs/SPHs) in group-2 are highly expressed in midgut, whole larva or whole adult libraries. In comparison, 46 SPs, 26 SPHs, and 37 multi-domain SPs/SPHs (i.e. PD/PLD-PLD≥1) in group-3 do not seem to be specifically expressed in digestive tract. There are 16 SPs and 2 SPH containing other types of putative regulatory domains (e.g. LDLa, CUB, Gd). Of the 337 SP and SPH genes, 159 were sorted into 46 groups (2–8 members/group) based on similar phylogenetic tree position, chromosomal location, and expression profile. This information and analysis, including improved gene models and protein sequences, constitute a solid foundation for functional analysis of the SP-related proteins in A. gambiae.
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      PubDate: 2017-08-04T14:31:28Z
      DOI: 10.1016/j.ibmb.2017.07.008
  • Gustatory receptor 22e is essential for sensing chloroquine and strychnine
           in Drosophila melanogaster
    • Authors: Seeta Poudel; Yunjung Kim; Junseok Kwak; Sangyun Jeong; Youngseok Lee
      Abstract: Publication date: Available online 24 July 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Seeta Poudel, Yunjung Kim, Junseok Kwak, Sangyun Jeong, Youngseok Lee
      Chloroquine, an amino quinolone derivative commonly used as an anti-malarial drug, is known to impart an unpleasant taste. Little research has been done to study chloroquine taste in insects, therefore, we examined both the deterrant properties and mechanisms underlying chloroquine perception in fruit flies. We identified the antifeedant effect of chloroquine by screening 21 gustatory receptor (Grs) mutants through behavioral feeding assays and electrophysiology experiments. We discovered that two molecular sensors, GR22e and GR33a, act as chloroquine receptors, and found that chloroquine-mediated activation of GRNs occurs through S-type sensilla. At the same time, we successfully recapitulated the chloroquine receptor by expressing GR22e in ectopic gustatory receptor neurons. We also found that GR22e forms a part of the strychnine receptor. We suggest that the Drosophila strychnine receptor might have a very complex structure since five different GRs are required for strychnine-induced action potentials.
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      PubDate: 2017-07-26T13:33:28Z
      DOI: 10.1016/j.ibmb.2017.07.007
  • Towards an understanding of the molecular basis of effective RNAi against
           a global insect pest, the whitefly Bemisia tabaci
    • Authors: Yuan Luo; Qingguo Chen; Junbo Luan; Seung Ho Chung; Joyce Van Eck; R. Turgeon; Angela E. Douglas
      Abstract: Publication date: Available online 21 July 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yuan Luo, Qingguo Chen, Junbo Luan, Seung Ho Chung, Joyce Van Eck, R. Turgeon, Angela E. Douglas
      In planta RNAi against essential insect genes offers a promising route to control insect crop pests, but is constrained for many insect groups, notably phloem sap-feeding hemipterans, by poor RNAi efficacy. This study conducted on the phloem-feeding whitefly Bemisia tabaci reared on tomato plants investigated the causes of low RNAi efficacy and routes to ameliorate the problem. Experiments using tomato transgenic lines containing ds-GFP (green fluorescent protein) revealed that full-length dsRNA is phloem-mobile, ingested by the insects, and degraded in the insect. We identified B. tabaci homologs of nuclease genes (dsRNases) in other insects that degrade dsRNA, and demonstrated that degradation of ds-GFP in B. tabaci is suppressed by administration of dsRNA against these genes. dsRNA against the nuclease genes was co-administered with dsRNA against two insect genes, an aquaporin AQP1 and sucrase SUC1, that are predicted to protect B. tabaci against osmotic collapse. When dsRNA constructs for AQP1, SUC1, dsRNase1 and dsRNase2 were stacked, insect mortality was significantly elevated to 50% over 6 days on artificial diets. This effect was accompanied by significant reduction in gene expression of the target genes in surviving diet-fed insects. This study offers proof-of-principle that the efficacy of RNAi against insect pests can be enhanced by using dsRNA to suppress the activity of RNAi-suppressing nuclease genes, especially where multiple genes with related physiological function but different molecular function are targeted.
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      PubDate: 2017-07-26T13:33:28Z
      DOI: 10.1016/j.ibmb.2017.07.005
  • Amblyomma maculatum SECIS binding protein 2 and putative selenoprotein P
           are indispensable for pathogen replication and tick fecundity
    • Authors: Khemraj Budachetri; Gary Crispell; Shahid Karim
      Abstract: Publication date: Available online 21 July 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Khemraj Budachetri, Gary Crispell, Shahid Karim
      Selenium, a vital trace element, is incorporated into selenoproteins to produce selenocysteine. Our previous studies have revealed an adaptive co-evolutionary process that has enabled the spotted fever-causing tick-borne pathogen Rickettsia parkeri to survive by manipulating an antioxidant defense system associated with selenium, which includes a full set of selenoproteins and other antioxidants in ticks. Here, we conducted a systemic investigation of SECIS binding protein 2 (SBP2) and putative selenoprotein P (SELENOP) by transcript silencing in adult female Gulf-coast ticks (Amblyomma maculatum). Knockdown of the SBP2 and SELENOP genes depleted the respective transcript levels of these tick selenogenes, and caused differential regulation of other antioxidants. Importantly, the selenium level in the immature and mature tick stages increased significantly after a blood meal, but the selenium level decreased in ticks after the SBP2 and SELENOP knockdowns. Moreover, the SBP2 knockdown significantly impaired both transovarial transmission of R. parkeri to tick eggs and egg hatching. Overall, our data offer new insight into the relationship between the SBP2 selenoprotein synthesis gene and the putative tick SELENOP gene. It also augments our understanding of selenoprotein synthesis, selenium maintenance and utilization, and bacterial colonization of a tick vector.
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      PubDate: 2017-07-26T13:33:28Z
      DOI: 10.1016/j.ibmb.2017.07.006
  • Gene expression changes in honey bees induced by sublethal imidacloprid
           exposure during the larval stage
    • Authors: Ming-Cheng Wu; Yu-Wen Chang; Kuang-Hui Lu; En-Cheng Yang
      Abstract: Publication date: Available online 18 July 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Ming-Cheng Wu, Yu-Wen Chang, Kuang-Hui Lu, En-Cheng Yang
      Honey bee larvae exposed to sublethal doses of imidacloprid show behavioural abnormalities as adult insects. Previous studies have demonstrated that this phenomenon originates from abnormal neural development in response to imidacloprid exposure. Here, we further investigated the global gene expression changes in the heads of newly emerged adults and observed that 578 genes showed more than 2-fold changes in gene expression after imidacloprid exposure. This information might aid in understanding the effects of pesticides on the health of pollinators. For example, the genes encoding major royal jelly proteins (MRJPs), a group of multifunctional proteins with significant roles in the sustainable development of bee colonies, were strongly downregulated. These downregulation patterns were further confirmed through analyses using quantitative reverse transcription-polymerase chain reaction on the heads of 6-day-old nurse bees. To our knowledge, this study is the first to demonstrate that sublethal doses of imidacloprid affect mrjp expression and likely weaken bee colonies.
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      PubDate: 2017-07-20T02:25:55Z
      DOI: 10.1016/j.ibmb.2017.06.016
  • TGF-β signaling regulates p-Akt levels via PP2A during diapause entry in
           the cotton bollworm, Helicoverpa armigera
    • Authors: Hai-Yin Li; Tao Wang; Yong-Pan Yang; Shao-Lei Geng; Wei-Hua Xu
      Abstract: Publication date: Available online 15 July 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Hai-Yin Li, Tao Wang, Yong-Pan Yang, Shao-Lei Geng, Wei-Hua Xu
      Akt, which is a key kinase in the insulin signaling pathway, plays important roles in glucose metabolism, cell proliferation, transcription and cell migration. Our previous studies indicated that low insulin levels and high p-Akt levels are present in diapause-destined individuals. Here, we show that PI3K, which is upstream of Akt, is low in diapause-destined pupal brains but high in p-Akt levels, implying that p-Akt is modified by factors other than the insulin signaling pathway. Protein phosphatase 2A (PP2A), which is a key regulator in the TGF-β signaling pathway, can directly bind to and dephosphorylate Akt. Low PP2A expression and activity in diapause-destined individuals suggest that a weak Akt dephosphorylation contributes to p-Akt accumulation. In addition, transforming growth factor-β receptor I (TβRI), which is upstream of PP2A, increases the activity of PP2A and decreases the p-Akt levels. These results show that TGF-β signaling decreases p-Akt levels by increasing the activity of PP2A. This is the first report showing that TGF-β signaling negatively regulates the insulin pathway in insect development or diapause.
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      PubDate: 2017-07-20T02:25:55Z
      DOI: 10.1016/j.ibmb.2017.07.003
  • Transcriptome analysis of Helicoverpa armigera male hairpencils: Alcohol
           biosynthesis and requirement for mating success
    • Authors: Mengfang Du; Wenhui Zhao; Russell Jurenka; Xiaoguang Liu; Xinming Yin; Qisheng Song; Shiheng An
      Abstract: Publication date: Available online 10 July 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Mengfang Du, Wenhui Zhao, Russell Jurenka, Xiaoguang Liu, Xinming Yin, Qisheng Song, Shiheng An
      Many female animals use different strategies to assess male quality to increase their own reproductive fitness. In moths, females usually use chemical signals (sex pheromones) to attract males from a distance. Once males approach a female, they release close range pheromones from hairpencils to facilitate female acceptance. However, detailed mechanisms involved in male sex pheromone biosynthesis and its action in promoting female acceptance have not yet been fully characterized. This study screened a series of candidate genes via a transcriptome analysis of the male hairpencil of Helicoverpa armigera. Using pharmacological inhibitor and RNAi-mediated knockdown assays, we demonstrated that Ca2+ and cyclic-AMP were involved in pheromone biosynthesis activating neuropeptide (PBAN)-induced male sex pheromone biosynthesis. The functional analysis of candidate enzymes involved in the male sex pheromone biosynthesis pathway demonstrated that a decreased mRNA levels of acetyl-CoA carboxylase, Δ11-desaturase, and fatty-acyl reductase 2 by RNAi-mediated knockdown led to a significant decrease in the production of fatty acyl alcohols and the efficacy of female acceptance. Our results demonstrated the important role of the fatty acyl alcohol biosynthetic pathway in a PBAN-induced male sex pheromone biosynthesis and the importance of hairpencil compounds in female mating acceptance.
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      PubDate: 2017-07-10T07:34:33Z
      DOI: 10.1016/j.ibmb.2017.07.001
  • BmCHSA-2b, a Lepidoptera specific alternative splicing variant of
           epidermal chitin synthase, is required for pupal wing development in
           Bombyx mori
    • Authors: Guangfeng Xu; Jie Zhang; Jia Liu; Yang Ding; Qili Feng; Qisheng Song; Sichun Zheng
      Abstract: Publication date: Available online 1 July 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Guangfeng Xu, Jie Zhang, Jia Liu, Yang Ding, Qili Feng, Qisheng Song, Sichun Zheng
      Insect chitin synthase A (CHSA) is an epidermis-specific enzyme that plays an essential role in insect development. In this study, the function and regulation of CHSA-2b, an alternative splicing variant of Bombxy mori CHSA that is discovered only in Lepidopteran insects, were investigated. Analysis of mRNA level showed that BmCHSA-2b was responsive to 20-hydroxyecdysone (20E) in pupal wing unlike BmCHSA-2a, which shares almost the identical sequence as BmCHSA-2b except the first 31 amino acids, suggesting that the expression of these two alternative splicing variants is driven by different promoters of CHSA gene. Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) analysis showed that BmCHSA-2b was up-regulated in the wing of mid-pupa unlike BmCHSA-2a, which was up-regulated in epidermis and wing disc at the beginning and end of pupal stage. Further analysis reveals that the up-regulations of BmCHSA-2a and BmCHSA-2b in pupal wing were consistent with the increase of chitin content and wing area at the same stages, respectively. Furthermore, the higher transcription level of BmCHSA-2b in the mid-pupal wing of male than that in female was consistent with the chitin content of pupal wing between genders. Injection of double-stranded RNAs of BmCHSA-2b resulted in the decrease in the area and chitin content of the wing, and irregular and crimpled vein. All these results together suggest that B. mori evolves an extra promoter in CHSA gene to activate BmCHSA-2b expression in the wing of mid-pupal stage in response to 20E, and BmCHSA-2b is required for the wing development in the mid-pupa of B. mori.
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      PubDate: 2017-07-10T07:34:33Z
      DOI: 10.1016/j.ibmb.2017.06.017
  • Investigation of the contribution of RyR target-site mutations in diamide
           resistance by CRISPR/Cas9 genome modification in Drosophila
    • Authors: Vassilis Douris; Kyriaki-Maria Papapostolou; Aris Ilias; Emmanuel Roditakis; Styliani Kounadi; Maria Riga; Ralf Nauen; John Vontas
      Abstract: Publication date: Available online 29 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Vassilis Douris, Kyriaki-Maria Papapostolou, Aris Ilias, Emmanuel Roditakis, Styliani Kounadi, Maria Riga, Ralf Nauen, John Vontas
      Diamide insecticides are used widely against lepidopteran pests, acting as potent activators of insect Ryanodine Receptors (RyRs) and thus inducing muscle contraction and eventually death. However, resistant phenotypes have recently evolved in the field, associated with the emergence of target site resistance mutations (G4946E/V and I4790M). We investigated the frequency of the mutations found in a resistant population of Tuta absoluta from Greece (G4946V–79% and I4790M–21%) and the associated diamide resistance profile: there are very high levels of resistance against chlorantraniliprole (9329-fold) and flubendiamide (4969-fold), but moderate levels against cyantraniliprole (191-fold). To further investigate functionally the contribution of each mutation in the resistant phenotype, we used CRISPR/Cas9 to generate genome modified Drosophila carrying alternative allele combinations, and performed toxicity bioassays against all three marketed diamides. Genome modified flies bearing the G4946V mutation exhibited high resistance to flubendiamide (91.3-fold) and chlorantraniliprole (194.7-fold), but low in cyantraniliprole (5.4-fold). Flies naturally bearing the I4790M mutation were moderately resistant to flubendiamide (15.3-fold) but less resistant to chlorantraniliprole (7.5-fold), and cyantraniliprole (2.3-fold). These findings provide in vivo functional genetic confirmation for the role and relative contribution of RyR mutations in diamide resistance and suggest that the three diamides employ different binding modes on the RyR protein.
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      PubDate: 2017-07-01T03:03:53Z
      DOI: 10.1016/j.ibmb.2017.06.013
  • Voltage-sensitive potassium channels expressed after 20-Hydroxyecdysone
           treatment of a mosquito cell line
    • Authors: Lacey J. Jenson; Baonan Sun; Jeffrey R. Bloomquist
      Abstract: Publication date: Available online 28 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Lacey J. Jenson, Baonan Sun, Jeffrey R. Bloomquist
      The goal of this research was to express receptors and ion channels in hormone-treated insect cell lines. Treatment of Anopheles gambiae Sua1B cells with 20-hydroxyecdysone showed an inhibition of cell growth over a time course of three days, with no change in cellular morphology. The effect of 20-hydroxyecdysone was enhanced in the presence of the potassium channel blocker 4-aminopyridine, but not tetraethylammonium. Concentration-response curves of 4-aminopyridine in the presence of 42 μM (1 mg/ml) 20-hydroxyecdysone showed similar IC50 values (6–10 μM) across 3 day exposures. Whole cell patch clamp confirmed the expression of delayed-rectifier (Kv2) potassium channels in hormone-supplemented Sua1B cells, whereas untreated Sua1B cells showed no evidence of Kv2 expression. The hormone-induced expression of Kv2 channels occurred in as little as 4 h after treatment, but were not observed after 24 h of exposure to 20-hydroxyecdysone, suggesting they played a role in cell death. The expressed channels had current-voltage relationships diagnostic for the Kv2 subtype, and were inhibited with an IC50 = 13 mM of tetraethylammonium. Overall, these parameters were similar to Anopheles gambiae Kv2 potassium channels expressed in HEK-293 cells. The induced presence of ion channels (and possibly receptors) in these cells has potential utility for high throughput screening and basic neuroscience research.
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      PubDate: 2017-07-01T03:03:53Z
      DOI: 10.1016/j.ibmb.2017.06.012
  • Characterization of three serotonin receptors from the small white
           butterfly, Pieris rapae
    • Authors: Yi-xiang Qi; Miao Jin; Xu-yang Ni; Gong-yin Ye; Youngseok Lee; Jia Huang
      Abstract: Publication date: Available online 27 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yi-xiang Qi, Miao Jin, Xu-yang Ni, Gong-yin Ye, Youngseok Lee, Jia Huang
      Serotonin (5-hydroxytryptamine, 5-HT) plays a key role in modulating diverse physiological processes and behaviors in both protostomes and deuterostomes. These functions are mediated through the binding of serotonin to its receptors, which are recognized as potential insecticide targets. We investigated the sequence, pharmacology and tissue distribution of three 5-HT receptors (Piera5-HT1A, Piera5-HT1B, Piera5-HT7) from the small white butterfly Pieris rapae, an important pest of cultivated cabbages and other mustard family crops. Activation of Piera5-HT1A or Piera5-HT1B by 5-HT inhibited the production of cAMP in a dose-dependent manner. Stimulation of Piera5-HT7 with 5-HT increased cAMP level significantly. Surprisingly, with the exception of 5-methoxytryptamine, agonists including α-methylserotonin, 8-Hydroxy-DPAT and 5-carboxamidotryptamine activated these receptors poorly. The results are consistent with previous findings in Manduca sexta. All three receptors were blocked by methiothepin, but ketanserin and yohimbine were not effective. The selective mammalian 5-HT receptor antagonists SB 216641 and SB 269970 displayed potent inhibition effects on Piera5-HT1B and Piera5-HT7 respectively. The results we achieved here indicate that the pharmacological properties of Lepidoptera 5-HT receptors are quite different from those in other insects and vertebrates and may contribute to development of new selective pesticides. This study offers important information on three 5-HT receptors from P. rapae that will facilitate further analysis of the functions of 5-HT receptors in insects.
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      PubDate: 2017-07-01T03:03:53Z
      DOI: 10.1016/j.ibmb.2017.06.011
  • Characterization and expression patterns of key ecdysteroid biosynthesis
           and signaling genes in a spider mite (Panonychus citri)
    • Authors: Gang Li; Jinzhi Niu; Moises Zotti; Qinzhe Sun; Lin Zhu; Jun Zhang; Chongyu Liao; Wei Dou; Dandan Wei; Jinjun Wang; Guy Smagghe
      Abstract: Publication date: Available online 20 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Gang Li, Jinzhi Niu, Moises Zotti, Qinzhe Sun, Lin Zhu, Jun Zhang, Chongyu Liao, Wei Dou, Dandan Wei, Jinjun Wang, Guy Smagghe
      Ecdysteroids play a crucial role in regulating molting in the phylum of Arthropoda and much is known with members of the subphylum of Hexapoda including the Insecta. However, this is still unclear in key pests as spider mites belonging to the subphylum of Chelicerata that originated earlier in the Cambrian period. In this study, we investigated 14 key genes of ecdysteroid biosynthesis and signaling and their expression over the different developmental stages in the citrus red mite, Panonychus citri (Acari: Stigmaeidae). P. citri is an economically important and widespread pest of citrus crops and it has five developmental stages of egg, larva, protonymph, deutonymph and adult. Typically, the expression of the ecdysteroid-synthesizing Halloween gene Spook (PcSpo) followed a positive zigzag-like pattern with a peak in the first half of each developmental stage and a drop in the second half prior to the molting to the next stage. Similar to PcSpo, PcDib, PcSad, PcRXR2, PcE75 and PcHR38 showed a positive zigzag-like expression pattern, while that of PcE78, PcHR3 and PcFTZ-F1 was opposite that we called a negative zigzag-like pattern. Silencing of the PcSpo gene by RNAi showed that molting was inhibited. Interestingly, we could rescue these RNAi effects by supplementing ponasterone A (PonA) and not by 20E, which is indicative that mites use PonA rather than 20E as ecdysteroid hormone. Modeling of the ecdysteroid receptor (PcEcR) hormone binding cavity also predicted binding of PonA, but showed a steric hindrance for 20E. We believe our data provide insight into the evolution and expression patterns of key ecdysteroid biosynthesis and signaling genes in a distant, non-insect species, and can become a foundation to develop new targets for controlling important agricultural pests such as spider mites.
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      PubDate: 2017-06-22T06:16:05Z
      DOI: 10.1016/j.ibmb.2017.06.009
  • Genes encoding cuticular proteins are components of the Nimrod gene
           cluster in Drosophila
    • Authors: Gyöngyi Cinege; János Zsámboki; Maite Vidal-Quadras; Anne Uv; Gábor Csordás; Viktor Honti; Erika Gábor; Zoltán Hegedűs; Gergely I.B. Varga; Attila L. Kovács; Gábor Juhász; Michael J. Williams; István Andó; Éva Kurucz
      Abstract: Publication date: Available online 17 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Gyöngyi Cinege, János Zsámboki, Maite Vidal-Quadras, Anne Uv, Gábor Csordás, Viktor Honti, Erika Gábor, Zoltán Hegedűs, Gergely I.B. Varga, Attila L. Kovács, Gábor Juhász, Michael J. Williams, István Andó, Éva Kurucz
      The Nimrod gene cluster, located on the second chromosome of Drosophila melanogaster, is the largest synthenic unit of the Drosophila genome. Nimrod genes show blood cell specific expression and code for phagocytosis receptors that play a major role in fruit fly innate immune functions. We previously identified three homologous genes (vajk-1, vajk-2 and vajk-3) located within the Nimrod cluster, which are unrelated to the Nimrod genes, but are homologous to a fourth gene (vajk-4) located outside the cluster. Here we show that, unlike the Nimrod candidates, the Vajk proteins are expressed in cuticular structures of the late embryo and the late pupa, indicating that they contribute to cuticular barrier functions.
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      PubDate: 2017-06-22T06:16:05Z
      DOI: 10.1016/j.ibmb.2017.06.006
  • Pharmacological characterisation and functional roles for egg-laying of a
           β-adrenergic-like octopamine receptor in the brown planthopper
           Nilaparvata lugens
    • Authors: Shun-Fan Wu; Xiao-Min Jv; Jian Li; Guang-Jian Xu; Xiao-Yi Cai; Cong-Fen Gao
      Abstract: Publication date: Available online 16 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Shun-Fan Wu, Xiao-Min Jv, Jian Li, Guang-Jian Xu, Xiao-Yi Cai, Cong-Fen Gao
      Octopamine, the invertebrate counterpart of adrenaline and noradrenaline, controls and modulates many physiological and behavioral processes in protostomes. It mediates its effects by binding to specific receptors belonging to the superfamily of G-protein coupled receptors. We report the cloning of a cDNA from the brown planthopper (Nloa2b2) sharing high similarity with members of the OA2B2 receptor class. Activation of NlOA2B2 by octopamine increased the production of cAMP in a dose-dependent manner (EC50 = 114 nM). Tyramine also activated the receptor but with much less potency than octopamine. Using a series of known agonists and antagonists of octopamine receptors and cAMP measurements, we observed a rather unique pharmacological profile of NlOA2B2. The potency ranking of the tested agonists was naphazoline > clonidine. The activated effect of octopamine is abolished by co-incubation with epinastine, mianserin, phentolamine, methiothepin, butaclamol or methysergide. Nloa2b2 was expressed in different developmental stages and in various tissues including female reproductive regions known to be involved in egg-laying behavior. Using in vivo pharmacology and RNAi methodology, we demonstrated that interference of NlOA2B2 signaling pathway had a strong impact on the egg-laying behavior of female brown planthopper. The data presented here mark the first comprehensive study—from gene to behavior—of a OA2B2 receptor in the rice brown planthopper.
      Graphical abstract image

      PubDate: 2017-06-22T06:16:05Z
      DOI: 10.1016/j.ibmb.2017.06.008
  • Severe developmental timing defects in the prothoracicotropic hormone
           (PTTH)-Deficient silkworm, Bombyx mori
    • Authors: Miwa Uchibori-Asano; Takumi Kayukawa; Hideki Sezutsu; Tetsuro Shinoda; Takaaki Daimon
      Abstract: Publication date: Available online 13 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Miwa Uchibori-Asano, Takumi Kayukawa, Hideki Sezutsu, Tetsuro Shinoda, Takaaki Daimon
      The insect neuropeptide prothoracicotropic hormone (PTTH) triggers the biosynthesis and release of the molting hormone ecdysone in the prothoracic gland (PG), thereby controlling the timing of molting and metamorphosis. Despite the well-documented physiological role of PTTH and its signaling pathway in the PG, it is not clear whether PTTH is an essential hormone for ecdysone biosynthesis and development. To address this question, we established and characterized a PTTH knockout line in the silkworm, Bombyx mori. We found that PTTH knockouts showed a severe developmental delay in both the larval and pupal stages. Larval phenotypes of PTTH knockouts can be classified into three major classes: (i) developmental arrest during the second larval instar, (ii) precocious metamorphosis after the fourth larval instar (one instar earlier in comparison to the control strain), and (iii) metamorphosis to normal-sized pupae after completing the five larval instar stages. In PTTH knockout larvae, peak levels of ecdysone titers in the hemolymph were dramatically reduced and the timing of peaks was delayed, suggesting that protracted larval development is a result of the reduced and delayed synthesis of ecdysone in the PG. Despite these defects, low basal levels of ecdysone were maintained in PTTH knockout larvae, suggesting that the primary role of PTTH is to upregulate ecdysone biosynthesis in the PG during molting stages, and low basal levels of ecdysone can be maintained in the absence of PTTH. We also found that mRNA levels of genes involved in ecdysone biosynthesis and ecdysteroid signaling pathways were significantly reduced in PTTH knockouts. Our results provide genetic evidence that PTTH is not essential for development, but is required to coordinate growth and developmental timing.
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      PubDate: 2017-06-16T09:30:47Z
      DOI: 10.1016/j.ibmb.2017.06.007
  • Sex pheromone in the moth Heliothis virescens is produced as a mixture of
           two pools: de novo and via precursor storage in glycerolipids
    • Authors: Stephen P. Foster; Karin G. Anderson; Jérôme Casas
      Abstract: Publication date: Available online 12 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Stephen P. Foster, Karin G. Anderson, Jérôme Casas
      Most species of moths use a female-produced volatile sex pheromone, typically produced via de novo fatty acid synthesis in a specialized gland, for communication among mates. While de novo biosynthesis of pheromone (DNP) is rapid, suggesting transient precursor acids, substantial amounts of pheromone precursor (and other) acids are stored, predominantly in triacylglycerols in the pheromone gland. Whether these stored acids are converted to pheromone later or not has been the subject of some debate. Using a tracer/tracee approach, in which we fed female Heliothis virescens U-13C-glucose, we were able to distinguish two pools of pheromone, in which precursors were temporally separated (after and before feeding on labeled glucose): DNP synthesized from a mixed tracer/tracee acetyl CoA pool after feeding, and pheromone made from precursor acids primarily synthesized before feeding, which we call recycled precursor fat pheromone (RPP). DNP titer varied from high (during scotophase) to low (photophase) and with presence/absence of pheromone biosynthesis activating neuropeptide (PBAN), in accord with native pheromone titer previously observed. By contrast, RPP was constant throughout the photoperiod and did not change with PBAN presence/absence. The amount of RPP (6.3–10.3 ng/female) was typically much lower than that of DNP, especially during the scotophase (peak DNP, 105 ng/female). We propose an integral role for stored fats in pheromone biosynthesis, in which they are hydrolyzed and re-esterified throughout the photoperiod, with a small proportion of liberated precursor acyl CoAs being converted to pheromone. During the sexually active period, release of PBAN results in increased flux of glucose (from trehalose) and hydrolyzed acids entering the mitochondria, producing acetyl CoA precursor for de novo fat and pheromone biosynthesis.
      Graphical abstract image

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

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

      PubDate: 2017-06-11T17:12:28Z
      DOI: 10.1016/j.ibmb.2017.06.005
  • Transcriptional signatures of parasitization and markers of colony decline
           in Varroa-infested honey bees (Apis mellifera)
    • Authors: Virginia Zanni; David A. Galbraith; Desiderato Annoscia; Christina M. Grozinger; Francesco Nazzi
      Abstract: Publication date: Available online 5 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Virginia Zanni, David A. Galbraith, Desiderato Annoscia, Christina M. Grozinger, Francesco Nazzi
      Extensive annual losses of honey bee colonies (Apis mellifera L.) reported in the northern hemisphere represent a global problem for agriculture and biodiversity. The parasitic mite Varroa destructor, in association with deformed wing virus (DWV), plays a key role in this phenomenon, but the underlying mechanisms are still unclear. To elucidate these mechanisms, we analyzed the gene expression profile of uninfested and mite infested bees, under laboratory and field conditions, highlighting the effects of parasitization on the bee's transcriptome under a variety of conditions and scenarios. Parasitization was significantly correlated with higher viral loads. Honey bees exposed to mite infestation exhibited an altered expression of genes related to stress response, immunity, nervous system function, metabolism and behavioural maturation. Additionally, mite infested young bees showed a gene expression profile resembling that of forager bees. To identify potential molecular markers of colony decline, the expression of genes that were commonly regulated across the experiments were subsequently assessed in colonies experiencing increasing mite infestation levels. These studies suggest that PGRP-2, hymenoptaecin, a glucan recognition protein, UNC93 and a p450 cytocrome maybe be suitable general biomarkers of Varroa-induced colony decline. Furthermore, the reliability of vitellogenin, a yolk protein previously identified as a good marker of colony survival, was confirmed here.
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      PubDate: 2017-06-06T16:21:58Z
      DOI: 10.1016/j.ibmb.2017.06.002
  • Quantitative proteomic analysis of the fall armyworm saliva
    • Authors: Flor E. Acevedo; Bruce A. Stanley; Anne Stanley; Michelle Peiffer; Dawn Luthe; Gary Felton
      Abstract: Publication date: Available online 4 June 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Flor E. Acevedo, Bruce A. Stanley, Anne Stanley, Michelle Peiffer, Dawn Luthe, Gary Felton
      Lepidopteran larvae secrete saliva on plant tissues during feeding. Components in the saliva may aid in food digestion, whereas other components are recognized by plants as cues to elicit defense responses. Despite the ecological and economical importance of these plant-feeding insects, knowledge of their saliva composition is limited to a few species. In this study, we identified the salivary proteins of larvae of the fall armyworm (FAW), Spodoptera frugiperda; determined qualitative and quantitative differences in the salivary proteome of the two host races—corn and rice strains—of this insect; and identified changes in total protein concentration and relative protein abundance in the saliva of FAW larvae associated with different host plants. Quantitative proteomic analyses were performed using labeling with isobaric tags for relative and absolute quantification followed by liquid chromatography-tandem mass spectrometry. In total, 98 proteins were identified (>99% confidence) in the FAW saliva. These proteins were further categorized into five functional groups: proteins potentially involved in (1) plant defense regulation, (2) herbivore offense, (3) insect immunity, (4) detoxification, (5) digestion, and (6) other functions. Moreover, there were differences in the salivary proteome between the FAW strains that were identified by label-free proteomic analyses. Thirteen differentially identified proteins were present in each strain. There were also differences in the relative abundance of eleven salivary proteins between the two FAW host strains as well as differences within each strain associated with different diets. The total salivary protein concentration was also different for the two strains reared on different host plants. Based on these results, we conclude that the FAW saliva contains a complex mixture of proteins involved in different functions that are specific for each strain and its composition can change plastically in response to diet type.
      Graphical abstract image

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

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

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

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

      PubDate: 2017-06-02T15:59:04Z
      DOI: 10.1016/j.ibmb.2017.05.007
  • C-type lectin interacting with β-integrin enhances hemocytic
           encapsulation in the cotton bollworm, Helicoverpa armigera
    • Authors: Pan Wang; Xiao-Rong Zhuo; Lin Tang; Xu-Sheng Liu; Yu-Feng Wang; Guo-Xiu Wang; Xiao-Qiang Yu; Jia-Lin Wang
      Abstract: Publication date: Available online 29 May 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Pan Wang, Xiao-Rong Zhuo, Lin Tang, Xu-Sheng Liu, Yu-Feng Wang, Guo-Xiu Wang, Xiao-Qiang Yu, Jia-Lin Wang
      The encapsulation reaction in invertebrates is analogous to granuloma formation in vertebrates, and this reaction is severely compromised when ecdysone signaling is blocked. However, the molecular mechanism underlying the encapsulation reaction and its regulation by ecdysone remains obscure. In our previous study, we found that the C-type lectin HaCTL3, from the cotton bollworm Helicoverpa armigera, is involved in anti-bacterial immune response, acting as a pattern recognition receptor (PRR). In the current study, we demonstrate that HaCTL3 is involved in defense against parasites and directly binds to the surface of nematodes. Our in vitro and in vivo studies indicate that HaCTL3 enhances hemocytic encapsulation and melanization, whereas H. armigera β-integrin (Haβ-integrin), located on the surface of hemocytes, participates in encapsulation. Additionally, co-immunoprecipitation experiments reveal HaCTL3 interacts with Haβ-integrin, and knockdown of Haβ-integrin leads to reduced encapsulation of HaCTL3-coated beads. These results indicate that Haβ-integrin serves as a hemocytic receptor of HaCTL3 during the encapsulation reaction. Furthermore, we demonstrate that 20-hydroxyecdysone (20E) treatment dramatically induces the expression of HaCTL3, and knockdown of the 20E receptor (EcR)/ultraspiracle (USP), abrogates this response. Overall, this study provides the first evidence of the presence of a hemocytic receptor (Haβ-integrin), that interacts with the PRR HaCTL3 to facilitate encapsulation reaction in insects and demonstrates the regulation of this process by the steroid hormone ecdysone.
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      PubDate: 2017-06-02T15:59:04Z
      DOI: 10.1016/j.ibmb.2017.02.004
  • Functional analysis of TcCTLP-5C2, a chymotrypsin-like serine protease
           needed for molting in Tribolium castaneum
    • Authors: Daniel Albaum; Gunnar Broehan; Subbaratnam Muthukrishnan; Hans Merzendorfer
      Abstract: Publication date: Available online 15 May 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Daniel Albaum, Gunnar Broehan, Subbaratnam Muthukrishnan, Hans Merzendorfer
      In a previous study, we have characterized a gene family encoding chymotrypsin-like proteases from the red flour beetle, Tribolium castaneum (TcCTLPs). We identified 14 TcCTLP genes that were predominantly expressed in the midgut, where they presumably function in digestion. Two genes (TcCTLP-6C and TcCTLP-5C 2 ), however, additionally showed considerable expression in the carcass, and RNAi studies demonstrated that they are required for molting (Broehan et al., 2010; Insect Biochem. Mol. Biol 40, 274-83). Thus, the enzyme has distinct functions in different physiological environments. To study molecular adaptations that facilitate enzyme function in different environments, we performed an in-depth analysis of the molecular and enzymatic properties of TcCTLP-5C2. We expressed different mutated versions of TcCTLP-5C2 in form of factor Xa activatable pro-enzymes in insect cells using a baculoviral expression system, and purified the recombinant proteins by affinity chromatography. By measuring and comparing the enzyme activities, we obtained information about the significance of single amino acid residues in motifs that determine substrate specificity and pH tolerance. Further, we showed that TcCTLP-5C2 is modified by N-glycosylation at amino acid position N137, which lies opposite to the catalytic cleft. Comparison of the enzymatic properties of non-glycosylated and glycosylated TcCTLP-5C2 versions showed that N-glycosylation decreases Vmax (maximum velocity) and kcat (turnover) while leaving the Km (specificity) unchanged. Thus, we provide evidence that N-glycosylation alters catalytic behavior by allosteric effects presumably due to altered structural dynamics as observed for chemically glycosylated enzymes.
      Graphical abstract image

      PubDate: 2017-05-17T14:08:22Z
      DOI: 10.1016/j.ibmb.2017.05.002
  • DINeR: Database for Insect Neuropeptide Research
    • Authors: Joseph G.C. Yeoh; Aniruddha A. Pandit; Meet Zandawala; Dick R. Nässel; Shireen-Anne Davies; Julian A.T. Dow
      Abstract: Publication date: Available online 11 May 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Joseph G.C. Yeoh, Aniruddha A. Pandit, Meet Zandawala, Dick R. Nässel, Shireen-Anne Davies, Julian A.T. Dow
      Neuropeptides are responsible for regulating a variety of functions, including development, metabolism, water and ion homeostasis, and as neuromodulators in circuits of the central nervous system. Numerous neuropeptides have been identified and characterized. However, both discovery and functional characterization of neuropeptides across the massive Class Insecta has been sporadic. To leverage advances in post-genomic technologies for this rapidly growing field, insect neuroendocrinology requires a consolidated, comprehensive and standardised resource for managing neuropeptide information. The Database for Insect Neuropeptide Research (DINeR) is a web-based database-application used for search and retrieval of neuropeptide information of various insect species detailing their isoform sequences, physiological functionality and images of their receptor-binding sites, in an intuitive, accessible and user-friendly format. The curated data includes representatives of 50 well described neuropeptide families from over 400 different insect species. Approximately 4700 FASTA formatted, neuropeptide isoform amino acid sequences and over 200 records of physiological functionality have been recorded based on published literature. Also available are images of neuropeptide receptor locations. In addition, the data include comprehensive summaries for each neuropeptide family, including their function, location, known functionality, as well as cladograms, sequence alignments and logos covering most insect orders. Moreover, we have adopted a standardized nomenclature to address inconsistent classification of neuropeptides. As part of the H2020 nEUROSTRESSPEP project, the data will be actively maintained and curated, ensuring a comprehensive and standardised resource for the scientific community. DINeR is publicly available at the project website:
      Graphical abstract image

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

      PubDate: 2017-05-02T12:50:08Z
      DOI: 10.1016/j.ibmb.2017.04.005
  • Arabidopsis glucosinolates trigger a contrasting transcriptomic response
           in a generalist and a specialist herbivore.
    • Authors: Fabian Schweizer; Hanna Heidel-Fischer; Heiko Vogel; Philippe Reymond
      Abstract: Publication date: Available online 26 April 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Fabian Schweizer, Hanna Heidel-Fischer, Heiko Vogel, Philippe Reymond
      Phytophagous insects have to deal with toxic defense compounds from their host plants. Although it is known that insects have evolved genes and mechanisms to detoxify plant allochemicals, how specialist and generalist precisely respond to specific secondary metabolites at the molecular level is less understood. Here we studied the larval performance and transcriptome of the generalist moth Heliothis virescens and the specialist butterfly Pieris brassicae feeding on Arabidopsis thaliana genotypes with different glucosinolate (GS) levels. H. virescens larvae gained significantly more weight on the GS-deficient mutant quadGS compared to wild-type (Col-0) plants. On the contrary, P. brassicae was unaffected by the presence of GS and performed equally well on both genotypes. Strikingly, there was a considerable differential gene expression in H. virescens larvae feeding on Col-0 compared to quadGS. In contrast, compared to H. virescens, P. brassicae displayed a much-reduced transcriptional activation when fed on both plant genotypes. Transcripts coding for putative detoxification enzymes were significantly upregulated in H. virescens, along with digestive enzymes and transposable elements. These data provide an unprecedented view on transcriptional changes that are specifically activated by GS and illustrate differential molecular responses that are linked to adaptation to diet in lepidopteran herbivores.
      Graphical abstract image

      PubDate: 2017-05-02T12:50:08Z
      DOI: 10.1016/j.ibmb.2017.04.004
  • Leptinotarsa cap ‘n’ collar isoform C/Kelch-like ECH associated
           protein 1 signaling is critical for the regulation of ecdysteroidogenesis
           in the larvae
    • Authors: Qiang-Kun Sun; Qing-Wei Meng; Qing-Yu Xu; Pan Deng; Wen-Chao Guo; Guo-Qing Li
      Abstract: Publication date: Available online 10 April 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Qiang-Kun Sun, Qing-Wei Meng, Qing-Yu Xu, Pan Deng, Wen-Chao Guo, Guo-Qing Li
      Drosophila cap ‘n’ collar isoform C (CncC) and Kelch-like ECH associated protein 1 (Keap1) regulate metamorphosis by transcriptional control of a subset of genes involved in ecdysteroidogenesis, 20-hydroxyecdysone (20E) signaling, and juvenile hormone (JH) degradation. In the present paper, we found that prothoracicotropic hormone signal was required for the activation of LdCncC and LdKeap1 in Leptinotarsa decemlineata. Moreover, RNA interference of LdCncC or LdKeap1 in the fourth-instar larvae delayed development. As a result, the treated larvae obtained heavier larval and pupal fresh weights and had larger body sizes than the controls. Furthermore, knockdown of LdCncC or LdKeap1 significantly reduced the mRNA levels of four ecdysone biosynthetic genes (Ldspo, Ldphm, Lddib and Ldsad), lowered 20E titer and decreased the transcript levels of five 20E response genes (LdEcR, LdUSP, LdE75, LdHR3 and LdFTZ-F1). However, the expression of two JH epoxide hydrolase genes and JH contents were not affected in the LdCncC and LdKeap1 RNAi larvae. Dietary supplementation with 20E shortened the developmental period to normal length, rescued the larval and pupal body mass rises, and recovered or even overcompensated the expression levels of the five 20E response genes in either LdCncC or LdKeap1 RNAi hypomorphs. Therefore, LdCncC/LdKeap1 signaling regulates several ecdysteroidogenesis genes, and consequently 20E pulse, to modulate the onset of metamorphosis in L. decemlineata.
      Graphical abstract image

      PubDate: 2017-04-11T09:51:24Z
      DOI: 10.1016/j.ibmb.2017.04.001
  • Manduca sexta hemolymph protease-1, activated by an unconventional
           non-proteolytic mechanism, mediates immune responses
    • Authors: Yan He; Yang Wang; Fan Yang; Haobo Jiang
      Abstract: Publication date: Available online 31 March 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yan He, Yang Wang, Fan Yang, Haobo Jiang
      Tissue damage or pathogen invasion triggers the auto-proteolysis of an initiating serine protease (SP), rapidly leading to sequential cleavage activation of other cascade members to set off innate immune responses in insects. Recently, we presented evidence that Manduca sexta hemolymph protease-1 zymogen (proHP1) is a member of the SP system in this species, and may activate proHP6. HP6 stimulates melanization and induces antimicrobial peptide synthesis. Here we report that proHP1 adopts an active conformation (*) to carry out its function, without a requirement for proteolytic activation. Affinity chromatography using HP1 antibodies isolated from induced hemolymph the 48 kDa proHP1 and also a 90 kDa band (detected by SDS-PAGE under reducing conditions) containing proHP1 and several serpins, as revealed by mass spectrometric analysis. Identification of tryptic peptides from these 90 kDa complexes included peptides from the amino-terminal regulatory part of proHP1, indicating that proHP1* was not cleaved, and that it had formed a complex with the serpins. As suicide inhibitors, serpins form SDS-stable, acyl-complexes when they are attacked by active proteases, indicating that proHP1* was catalytically active. Detection of M. sexta serpin-1, 4, 9, 13 and smaller amounts of serpin-3, 5, 6 in the complexes suggests that it is regulated by multiple serpins in hemolymph. We produced site-directed mutants of proHP1b for cleavage by bovine blood coagulation factor Xa at the designed proteolytic activation site, to generate a form of proHP1b that could be activated by Factor Xa. However, proHP1b cut by Factor Xa failed to activate proHP6 and, via HP6, proHP8 or proPAP1. This negative result is consistent with the suggestion that proHP1* is a physiological mediator of immune responses. Further research is needed to investigate the conformational change that results in conversion of proHP1 to active proHP1*.
      Graphical abstract image

      PubDate: 2017-04-04T09:49:20Z
      DOI: 10.1016/j.ibmb.2017.03.008
  • Design of larval chemical attractants based on odorant response spectra of
           olfactory receptors in the cotton bollworm
    • Authors: Chang Di; Chao Ning; Ling-Qiao Huang; Chen-Zhu Wang
      Abstract: Publication date: Available online 31 March 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Chang Di, Chao Ning, Ling-Qiao Huang, Chen-Zhu Wang
      Lepidopteran caterpillars rely on olfaction and gustation to discriminate among food sources. Compared to the larval gustation, the larval olfaction has been poorly investigated. To uncover the molecular basis of olfaction in Helicoverpa armigera larvae, we identified 17 Or genes in larval antennae and maxillae using transcriptome sequencing, and functionally identified the response spectra of seven Ors to ecologically relevant odorants. Innate behavioural responses of larvae to active odorants were evaluated in chemotaxis assays. Several odorant blends were formulated based on the Ors tuning spectra and caterpillar chemotaxis. A four-component blend strongly attracted H. armigera larvae, and cis-jasmone and 1-pentanol were identified as essential components. Localization analyses showed that the two Ors detecting these components (Or41 and Or52) were expressed in the same sensory neurons. This is the first evidence that Ors in a polyphagous caterpillar respond to odorants in a combinatorial manner. The design of attractants to target specific olfactory pathways may promote the development of new baits for pest management.
      Graphical abstract image

      PubDate: 2017-04-04T09:49:20Z
      DOI: 10.1016/j.ibmb.2017.03.007
  • Afidopyropen: New and potent modulator of insect transient receptor
           potential channels
    • Authors: Ramani Kandasamy; Damian London; Lynn Stam; Wolfgang von Deyn; Xilong Zhao; Vincent L. Salgado; Alexandre Nesterov
      Abstract: Publication date: Available online 24 March 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Ramani Kandasamy, Damian London, Lynn Stam, Wolfgang von Deyn, Xilong Zhao, Vincent L. Salgado, Alexandre Nesterov
      The commercial insecticides pymetrozine and pyrifluquinazon control plant-sucking pests by disturbing their coordination and ability to feed. We have previously shown that these compounds act by overstimulating and eventually silencing vanilloid-type transient receptor potential (TRPV) channels, which consist of two proteins, Nanchung and Inactive, which are co-expressed exclusively in insect chordotonal stretch receptor neurons. Here we show that a new insecticidal compound, afidopyropen, modulates chordotonal organs of American grasshoppers (Schistocerca americana) in the same fashion. Afidopyropen stimulated heterologously expressed TRPV channels from two different insect species, fruit fly (Drosophila melanogaster) and pea aphid (Acyrthosiphon pisum), but not the mammalian TRPV channel TRPV4. Activation of the insect TRPVs required simultaneous expression of both Nanchung and Inactive proteins. Tritium-labeled afidopyropen bound fruit fly TRPVs with higher affinity than pymetrozine and competed with pymetrozine for binding. Nanchung protein formed the main binding interface for afidopyropen, whereas co-expression of Inactive dramatically increased binding affinity. Another modulator of chordotonal organs, flonicamid, did not activate insect TRPV channels, nor did it compete with afidopyropen for binding, indicating that it has a different target protein. These results define afidopyropen as a new, potent and specific modulator of insect TRPV channels, and provide insight into the unique binding mode for these compounds.
      Graphical abstract image

      PubDate: 2017-03-28T09:07:02Z
      DOI: 10.1016/j.ibmb.2017.03.005
  • The role of miR-2∼13∼71 cluster in resistance to deltamethrin
           in Culex pipiens pallens
    • Authors: Qin Guo; Yun Huang; Feifei Zou; Bingqian Liu; Mengmeng Tian; Wenyun Ye; Juxin Guo; Xueli Sun; Dan Zhou; Yan Sun; Lei Ma; Bo Shen; Changliang Zhu
      Abstract: Publication date: Available online 23 March 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Qin Guo, Yun Huang, Feifei Zou, Bingqian Liu, Mengmeng Tian, Wenyun Ye, Juxin Guo, Xueli Sun, Dan Zhou, Yan Sun, Lei Ma, Bo Shen, Changliang Zhu
      Excessive and continuous application of deltamethrin has resulted in the development of deltamethrin resistance among mosquitoes, which becomes a major obstacle for mosquito control. In a previous study, differentially expressed miRNAs between deltamethrin-susceptible (DS) strain and deltamethrin-resistant (DR) strain using illumina sequencing in Culex pipiens pallens were identified. In this study, we applied RNAi and the Centers for Disease Control and Prevention (CDC) bottle bioassay to investigate the relationship between miR-2∼13∼71 cluster (miR-2, miR-13 and miR-71) and deltamethrin resistance. We used quantitative real-time PCR (qRT-PCR) to measure expression levels of miR-2∼13∼71 clusters. MiR-2∼13∼71 cluster was down regulated in adult female mosquitoes from the DR strain and played important roles in deltamethrin resistance through regulating target genes, CYP9J35 and CYP325BG3. Knocking down CYP9J35 and CYP325BG3 resulted in decreased mortality of DR mosquitoes. This study provides the first evidence that miRNA clusters are associated with deltamethrin resistance in mosquitoes. Moreover, we investigated the regulatory networks formed between miR-2∼13∼71 cluster and its target genes, which provide a better understanding of the mechanism involved in deltamethrin resistance.
      Graphical abstract image

      PubDate: 2017-03-28T09:07:02Z
      DOI: 10.1016/j.ibmb.2017.03.006
  • Changes in microRNA abundance may regulate diapause in the flesh fly,
           Sarcophaga bullata
    • Authors: Julie A. Reynolds; Justin T. Peyton; David L. Denlinger
      Abstract: Publication date: Available online 12 March 2017
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Julie A. Reynolds, Justin T. Peyton, David L. Denlinger
      Diapause, an alternative developmental pathway characterized by changes in developmental timing and metabolism, is coordinated by molecular mechanisms that are not completely understood. MicroRNA (miRNA) mediated gene silencing is emerging as a key component of animal development and may have a significant role in initiating, maintaining, and terminating insect diapause. In the present study, we test this possibility by using high-throughput sequencing and qRT-PCR to discover diapause-related shifts in miRNA abundance in the flesh fly, Sarcophaga bullata. We identified ten evolutionarily conserved miRNAs that were differentially expressed in diapausing pupae compared to their nondiapausing counterparts. miR-289-5p and miR-1-3p were overexpressed in diapausing pupae and may be responsible for silencing expression of candidate genes during diapause. miR-9c-5p, miR-13b-3p, miR-31a-5p, miR-92b-3p, miR-275-3p, miR-276a-3p, miR-277-3p, and miR-305-5p were underexpressed in diapausing pupae and may contribute to increased expression of heat shock proteins and other factors necessary for the enhanced environmental stress-response that is a feature of diapause. In S. bullata, a maternal effect blocks the programming of diapause in progeny of females that have experienced pupal diapause, and in this study we report that several miRNAs, including MiR-263a-5p, miR-100-5p, miR-125-5p, and let-7-5p were significantly overexpressed in such nondiapausing flies and may prevent entry into diapause. Together these miRNAs appear to be integral to the molecular processes that mediate entry into diapause.
      Graphical abstract image

      PubDate: 2017-03-13T01:54:02Z
      DOI: 10.1016/j.ibmb.2017.03.002
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