for Journals by Title or ISSN
for Articles by Keywords
  Subjects -> BIOLOGY (Total: 2954 journals)
    - BIOCHEMISTRY (230 journals)
    - BIOENGINEERING (102 journals)
    - BIOLOGY (1414 journals)
    - BIOPHYSICS (45 journals)
    - BIOTECHNOLOGY (205 journals)
    - BOTANY (214 journals)
    - CYTOLOGY AND HISTOLOGY (26 journals)
    - ENTOMOLOGY (63 journals)
    - GENETICS (161 journals)
    - MICROBIOLOGY (255 journals)
    - MICROSCOPY (10 journals)
    - ORNITHOLOGY (26 journals)
    - PHYSIOLOGY (69 journals)
    - ZOOLOGY (134 journals)

BIOCHEMISTRY (230 journals)                  1 2     

Showing 1 - 0 of 0 Journals sorted alphabetically
AAPS PharmSciTech     Hybrid Journal   (Followers: 6)
Acetic Acid Bacteria     Open Access   (Followers: 1)
ACS Central Science     Open Access   (Followers: 4)
ACS Chemical Biology     Full-text available via subscription   (Followers: 180)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 15)
Acta Crystallographica Section D : Biological Crystallography     Hybrid Journal   (Followers: 10)
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: 7)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 14)
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: 7)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 60)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 13)
American Journal of Polymer Science     Open Access   (Followers: 22)
Amino Acids     Hybrid Journal   (Followers: 8)
Analytical Biochemistry     Hybrid Journal   (Followers: 140)
Angiogenesis     Hybrid Journal   (Followers: 3)
Annals of Clinical Biochemistry     Hybrid Journal   (Followers: 8)
Annual Review of Biochemistry     Full-text available via subscription   (Followers: 50)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 9)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 43)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 16)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 5)
Archives of Biochemistry and Biophysics     Hybrid Journal   (Followers: 22)
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: 19)
Biochemical and Molecular Medicine     Full-text available via subscription   (Followers: 4)
Biochemical Compounds     Open Access  
Biochemical Engineering Journal     Hybrid Journal   (Followers: 13)
Biochemical Genetics     Hybrid Journal   (Followers: 3)
Biochemical Journal     Full-text available via subscription   (Followers: 25)
Biochemical Pharmacology     Hybrid Journal   (Followers: 7)
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: 233)
Biochemistry & Pharmacology : Open Access     Open Access   (Followers: 3)
Biochemistry & Physiology : Open Access     Open Access  
Biochemistry (Moscow)     Hybrid Journal   (Followers: 4)
Biochemistry (Moscow) Supplement Series A: Membrane and Cell Biology     Hybrid Journal   (Followers: 3)
Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry     Hybrid Journal   (Followers: 3)
Biochemistry and Biophysics Reports     Open Access  
Biochemistry and Cell Biology     Full-text available via subscription   (Followers: 15)
Biochemistry and Molecular Biology Education     Hybrid Journal   (Followers: 5)
Biochemistry and Molecular Biology of Fishes     Full-text available via subscription   (Followers: 1)
Biochemistry Research International     Open Access   (Followers: 5)
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids     Hybrid Journal   (Followers: 9)
Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease     Hybrid Journal   (Followers: 16)
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research     Hybrid Journal   (Followers: 7)
Biochimie     Hybrid Journal   (Followers: 6)
Biochimie Open     Open Access  
Bioconjugate Chemistry     Full-text available via subscription   (Followers: 30)
BioDrugs     Full-text available via subscription   (Followers: 8)
Bioelectrochemistry     Hybrid Journal   (Followers: 1)
Biofuels     Hybrid Journal   (Followers: 10)
Biogeochemistry     Hybrid Journal   (Followers: 11)
BioInorganic Reaction Mechanisms     Hybrid Journal   (Followers: 1)
Biokemistri     Open Access  
Biological Chemistry     Partially Free   (Followers: 26)
Biomaterials Research     Open Access   (Followers: 4)
Biomedicines     Open Access   (Followers: 1)
BioMolecular Concepts     Hybrid Journal   (Followers: 2)
Bioscience, Biotechnology, and Biochemistry     Hybrid Journal   (Followers: 25)
Biosimilars     Open Access   (Followers: 1)
Biotechnology and Applied Biochemistry     Hybrid Journal   (Followers: 44)
Bitácora Digital     Open Access  
BMC Biochemistry     Open Access   (Followers: 14)
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca : Food Science and Technology     Open Access  
Carbohydrate Polymers     Hybrid Journal   (Followers: 7)
Cell Biochemistry and Biophysics     Hybrid Journal   (Followers: 5)
Cell Biochemistry and Function     Hybrid Journal   (Followers: 4)
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: 21)
Chemical Engineering Journal     Hybrid Journal   (Followers: 27)
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: 5)
Chemistry & Biology     Full-text available via subscription   (Followers: 29)
Chemistry and Ecology     Hybrid Journal  
ChemTexts     Hybrid Journal  
Clinica Chimica Acta     Hybrid Journal   (Followers: 36)
Clinical Biochemist Reviews     Full-text available via subscription   (Followers: 1)
Clinical Biochemistry     Hybrid Journal   (Followers: 19)
Clinical Chemistry     Full-text available via subscription   (Followers: 67)
Clinical Chemistry and Laboratory Medicine     Hybrid Journal   (Followers: 62)
Clinical Lipidology     Full-text available via subscription  
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: 7)
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: 9)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 4)
Current Chemical Biology     Hybrid Journal   (Followers: 2)
Current Medicinal Chemistry     Hybrid Journal   (Followers: 14)
Current Opinion in Chemical Biology     Hybrid Journal   (Followers: 22)
Current Opinion in Lipidology     Hybrid Journal   (Followers: 5)
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: 58)
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: 3)
Frontiers in Molecular Biosciences     Open Access   (Followers: 2)
Frontiers in Natural Product Chemistry     Hybrid Journal  
Global Biogeochemical Cycles     Full-text available via subscription   (Followers: 12)
Green Chemistry     Full-text available via subscription   (Followers: 9)
Histochemistry and Cell Biology     Hybrid Journal   (Followers: 4)
Indian Journal of Biochemistry and Biophysics (IJBB)     Open Access   (Followers: 3)
Indian Journal of Clinical Biochemistry     Hybrid Journal   (Followers: 1)
Indonesian Biomedical Journal     Open Access  
Insect Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 3)
International Journal of Biochemistry & Cell Biology     Hybrid Journal   (Followers: 7)
International Journal of Biochemistry and Biophysics     Open Access   (Followers: 1)
International Journal of Biological Chemistry     Open Access   (Followers: 4)
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 5)
International Journal of Food Contamination     Open Access  
International Journal of Plant Physiology and Biochemistry     Open Access  
International Journal of Plant Research     Open Access   (Followers: 3)
International Journal of Secondary Metabolite     Open Access   (Followers: 1)
Invertebrate Immunity     Open Access   (Followers: 1)
JBIC Journal of Biological Inorganic Chemistry     Hybrid Journal   (Followers: 4)
Journal of Microbial & Biochemical Technology     Open Access   (Followers: 1)
Journal of Applied Biology & Biotechnology     Open Access   (Followers: 1)
Journal of Bioactive and Compatible Polymers     Hybrid Journal   (Followers: 2)
Journal of Biochemistry     Hybrid Journal   (Followers: 42)
Journal of Biological Chemistry     Full-text available via subscription   (Followers: 175)
Journal of Biomaterials Science, Polymer Edition     Hybrid Journal   (Followers: 9)
Journal of Carbohydrate Chemistry     Hybrid Journal   (Followers: 7)
Journal of Cellular Biochemistry     Hybrid Journal   (Followers: 5)
Journal of Chemical Biology     Hybrid Journal   (Followers: 1)
Journal of Chemical Neuroanatomy     Hybrid Journal  
Journal of Clinical Lipidology     Hybrid Journal   (Followers: 1)
Journal of Comparative Physiology B : Biochemical, Systemic, and Environmental Physiology     Hybrid Journal   (Followers: 4)
Journal of Drug Discovery and Therapeutics     Open Access   (Followers: 1)
Journal of Enzyme Inhibition and Medicinal Chemistry     Hybrid Journal   (Followers: 4)
Journal of Evolutionary Biochemistry and Physiology     Hybrid Journal  
Journal of Food and Drug Analysis     Open Access  
Journal of Forensic Toxicology and Pharmacology     Hybrid Journal   (Followers: 3)
Journal of Inborn Errors of Metabolism and Screening     Open Access  
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 4)
Journal of Investigational Biochemistry     Open Access   (Followers: 2)
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: 24)
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: 5)
Journal of Steroid Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 2)
Journal of Virology & Antiviral Research     Hybrid Journal   (Followers: 3)
Journal of Wood Chemistry and Technology     Hybrid Journal   (Followers: 7)
La Rivista Italiana della Medicina di Laboratorio - Italian Journal of Laboratory Medicine     Hybrid Journal  
Lab on a Chip     Full-text available via subscription   (Followers: 33)
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: 4)
Molecular Aspects of Medicine     Hybrid Journal   (Followers: 5)
Molecular Informatics     Hybrid Journal   (Followers: 4)
Molecular inhibitors in targeted therapy     Open Access  
Moscow University Chemistry Bulletin     Hybrid Journal   (Followers: 1)
Mycology : An International Journal on Fungal Biology     Hybrid Journal   (Followers: 4)
Natural Products and Bioprospecting     Open Access   (Followers: 3)
Nature Chemical Biology     Full-text available via subscription   (Followers: 67)
Nature Communications     Open Access   (Followers: 110)
Neurosignals     Open Access   (Followers: 2)
Novelty in Biomedicine     Open Access  
Ocean Acidification     Open Access   (Followers: 3)
Organic & Biomolecular Chemistry     Full-text available via subscription   (Followers: 88)
Peptidomics     Open Access  
Pesticide Biochemistry and Physiology     Hybrid Journal   (Followers: 4)
Pflugers Archiv European Journal of Physiology     Hybrid Journal   (Followers: 3)
Pharmaceutical Bioprocessing     Full-text available via subscription   (Followers: 1)
Pharmacognosy Magazine     Open Access   (Followers: 2)

        1 2     

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  [3038 journals]
  • Differential gene expression underlying ovarian phenotype determination in
           honey bee, Apis mellifera L, caste development
    • Authors: Denyse Cavalcante Lago; Fernanda Carvalho Humann; Angel Roberto Barchuk; Kuruvilla Joseph Abraham; Klaus Hartfelder
      Pages: 1 - 12
      Abstract: Publication date: Available online 5 October 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Denyse Cavalcante Lago, Fernanda Carvalho Humann, Angel Roberto Barchuk, Kuruvilla Joseph Abraham, Klaus Hartfelder
      Adult honey bee queens and workers drastically differ in ovary size. This adult ovary phenotype difference becomes established during the final larval instars, when massive programmed cell death leads to the degeneration of 95–99% of the ovariole anlagen in workers. The higher juvenile hormone (JH) levels in queen larvae protect the ovaries against such degeneration. To gain insights into the molecular architecture underlying this divergence critical for adult caste fate and worker sterility, we performed a microarray analysis on fourth and early fifth instar queen and worker ovaries. For the fourth instar we found nine differentially expressed genes (DEGs) with log2FC > 1.0, but this number increased to 56 in early fifth-instar ovaries. We selected 15 DEGs for quantitative PCR (RT-qPCR) analysis. Nine differed significantly by the variables caste and/or development. Interestingly, genes with enzyme functions were higher expressed in workers, while those related to transcription and signaling had higher transcript levels in queens. For the RT-qPCR confirmed genes we analyzed their response to JH. This revealed a significant up-regulation for two genes, a short chain dehydrogenase reductase (sdr) and a heat shock protein 90 (hsp90). Five other genes, including hsp60 and hexamerin 70b (hex70b), were significantly down-regulated by JH. The sdr gene had previously come up as differentially expressed in other transcriptome analyses on honey bee larvae and heat shock proteins are frequently involved in insect hormone responses, this making them interesting candidates for further functional assays.
      Graphical abstract image

      PubDate: 2016-10-08T01:20:57Z
      DOI: 10.1016/j.ibmb.2016.10.001
      Issue No: Vol. 79 (2016)
  • Sperm-less males modulate female behaviour in Ceratitis capitata (Diptera:
    • Authors: Paolo Gabrieli; Francesca Scolari; Alessandro Di Cosimo; Grazia Savini; Marco Fumagalli; Ludvik M. Gomulski; Anna R. Malacrida; Giuliano Gasperi
      Pages: 13 - 26
      Abstract: Publication date: Available online 6 October 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Paolo Gabrieli, Francesca Scolari, Alessandro Di Cosimo, Grazia Savini, Marco Fumagalli, Ludvik M. Gomulski, Anna R. Malacrida, Giuliano Gasperi
      In the Mediterranean fruit fly, Ceratitis capitata (Wiedemann)(Diptera: Tephritidae), mating has a strong impact on female biology, leading to a decrease in sexual receptivity and increased oviposition and fecundity. Previous studies suggest that sperm transfer may play a role in inducing these behavioural changes. Here we report the identification of a medfly innexin gene, Cc-inx5, whose expression is limited to the germ-line of both sexes. Through RNA interference of this gene, we generated males without testes and, consequently, sperm, but apparently retaining all the other reproductive organs intact. These sperm-less males were able to mate and, like their wild-type counterparts, to induce in their partners increased oviposition rates and refractoriness to remating. Interestingly, matings to sperm-less males results in oviposition rates higher than those induced by copulation with control males. In addition, the observed female post-mating behavioural changes were congruent with changes in transcript abundance of genes known to be regulated by mating in this species. Our results suggest that sperm transfer is not necessary to reduce female sexual receptivity and to increase oviposition and fecundity. These data pave the way to a better understanding of the role/s of seminal components in modulating female post-mating responses. In the long term, this knowledge will be the basis for the development of novel approaches for the manipulation of female fertility, and, consequently, innovative tools to be applied to medfly control strategies in the field.
      Graphical abstract image

      PubDate: 2016-10-08T01:20:57Z
      DOI: 10.1016/j.ibmb.2016.10.002
      Issue No: Vol. 79 (2016)
  • Digestive proteolysis in the Colorado potato beetle, Leptinotarsa
           decemlineata: Activity-based profiling and imaging of a multipeptidase
    • Authors: Jaroslav Srp; Martina Nussbaumerová; Martin Horn; Michael Mareš
      Pages: 1 - 11
      Abstract: Publication date: Available online 15 August 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Jaroslav Srp, Martina Nussbaumerová, Martin Horn, Michael Mareš
      The Colorado potato beetle (CPB), Leptinotarsa decemlineata, is a major pest of potato plants, and its digestive system is a promising target for development of pest control strategies. This work focuses on functional proteomic analysis of the digestive proteolytic enzymes expressed in the CPB gut. We identified a set of peptidases using imaging with specific activity-based probes and activity profiling with selective substrates and inhibitors. The secreted luminal peptidases were classified as: (i) endopeptidases of cathepsin D, cathepsin L, and trypsin types and (ii) exopeptidases with aminopeptidase (cathepsin H), carboxypeptidase (serine carboxypeptidase, prolyl carboxypeptidase), and carboxydipeptidase (cathepsin B) activities. The proteolytic arsenal also includes non-luminal peptidases with prolyl oligopeptidase and metalloaminopeptidase activities. Our results indicate that the CPB gut employs a multienzyme network of peptidases with complementary specificities to efficiently degrade ingested proteins. This proteolytic system functions in both CPB larvae and adults and is controlled mainly by cysteine and aspartic peptidases and supported by serine and metallopeptidases. The component enzymes identified here are potential targets for inhibitors with tailored specificities that could be engineered into potato plants to confer resistance to CPB.
      Graphical abstract image

      PubDate: 2016-08-18T02:27:48Z
      DOI: 10.1016/j.ibmb.2016.08.004
      Issue No: Vol. 78 (2016)
  • Farnesyl biliverdins IXα are novel ligands of biliproteins from moths of
           the Noctuoidea superfamily: A chemosystematic view of the Lepidoptera
    • Authors: Hartmut Kayser; Manfred Nimtz
      Pages: 12 - 19
      Abstract: Publication date: Available online 28 August 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Hartmut Kayser, Manfred Nimtz
      Bilins, derived from biliverdin IXα, are known from animals, plants and microorganisms, where they play vital roles as light-absorbing pigments. Bilins occur also in many insects. Recently, we discovered in insects a novel structural type of bilins with a farnesyl substituent at pyrrole ring A of biliverdin IXα. The first of these unusual bilins with a molecular mass of 852 (C48H60O10N4) was identified in Cerura vinula, subsequently in Spodoptera littoralis; both species are members of the Noctuoidea superfamily of moths. From an evolutionary point of view, it was of interest to examine other species and families of this monophyletic clade. Here, we show that other moths species in this clade (three Notodontidae species, one Erebidae species, and one Noctuidae species) have farnesylated biliverdins IXα that are present as a mixture of three bilins, differing by the number of oxygen atoms (O8-10). These bilins are associated with typical hemolymph storage proteins, which were identified by mass spectroscopic sequencing of tryptic peptides as arylphorins (a class of 500-kDa hexamerins) in the Notodontidae and Erebidae families, and as 350-kDa very high-density lipoproteins in the Noctuidae family. Circular dichroism spectroscopy revealed that the bilins adopt opposite conformations in complex with the two different classes of proteins. At present, farnesylated biliverdins and IXα-isomers of bilins in general are known only from species of the Noctuoidea clade; the sister clades of Bombycoidea and Papilionoidea synthesise the IXγ-isomer of biliverdin and derivatives thereof.
      Graphical abstract image

      PubDate: 2016-08-31T03:51:09Z
      DOI: 10.1016/j.ibmb.2016.08.007
      Issue No: Vol. 78 (2016)
  • Multiple cis-acting elements involved in up-regulation of a cytochrome
           P450 gene conferring resistance to deltamethrin in small brown
           planthopper, Laodelphax striatellus (Fallén)
    • Authors: Jian Pu; Haina Sun; Jinda Wang; Min Wu; Kangxu Wang; Ian Denholm; Zhaojun Han
      Pages: 20 - 28
      Abstract: Publication date: Available online 31 August 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Jian Pu, Haina Sun, Jinda Wang, Min Wu, Kangxu Wang, Ian Denholm, Zhaojun Han
      As well as arising from single point mutations in binding sites or detoxifying enzymes, it is likely that insecticide resistance mechanisms are frequently controlled by multiple genetic factors, resulting in resistance being inherited as a quantitative trait. However, empirical evidence for this is still rare. Here we analyse the causes of up-regulation of CYP6FU1, a monoxygenase implicated in resistance to deltamethrin in the rice pest Laodelphax striatellus. The 5′-flanking region of this gene was cloned and sequenced from individuals of a susceptible and a resistant strain. A luminescent reporter assay was used to evaluate different 5′-flanking regions and their fragments for promoter activity. Mutations enhancing promoter activity in various fragments were characterized, singly and in combination, by site mutation recovery. Nucleotide diversity in flanking sequences was greatly reduced in deltamethrin-resistant insects compared to susceptible ones. Phylogenetic sequence analysis found that CYP6FU1 had five different types of 5′-flanking region. All five types were present in a susceptible strain but only a single type showing the highest promoter activity was present in a resistant strain. Four cis-acting elements were identified whose influence on up-regulation was much more pronounced in combination than when present singly. Of these, two were new transcription factor (TF) binding sites produced by mutations, another one was also a new TF binding site alternated from an existing one, and the fourth was a unique transcription start site. These results demonstrate that multiple cis-acting elements are involved in up-regulating CYP6FU1 to generate a resistance phenotype.
      Graphical abstract image

      PubDate: 2016-09-06T00:52:58Z
      DOI: 10.1016/j.ibmb.2016.08.008
      Issue No: Vol. 78 (2016)
  • Precise genome editing in the silkworm Bombyx mori using TALENs and ds-
           and ssDNA donors – A practical approach
    • Authors: Yoko Takasu; Isao Kobayashi; Toshiki Tamura; Keiro Uchino; Hideki Sezutsu; Michal Zurovec
      Pages: 29 - 38
      Abstract: Publication date: Available online 25 August 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yoko Takasu, Isao Kobayashi, Toshiki Tamura, Keiro Uchino, Hideki Sezutsu, Michal Zurovec
      Engineered nucleases are able to introduce double stranded breaks at desired genomic locations. The breaks can be repaired by an error-prone non-homologous end joining (NHEJ) mechanism, or the repair process can be exploited to introduce precise DNA modifications by homology-directed repair (HDR) when provided with a suitable donor template. We designed a series of DNA donors including long dsDNA plasmids as well as short ssDNA oligonucleotides and compared the effectiveness of their utilization during gene targeting with highly efficient transcription activator-like effector nucleases (TALENs). While the use of long dsDNA donors for the incorporation of larger DNA fragments in Bombyx is still a problem, short single-stranded oligodeoxynucleotides (ssODNs) are incorporated quite efficiently. We show that appropriately designed ssODNs were integrated into germ cells in up to 79% of microinjected individuals and describe in more detail the conditions for the precise genome editing of Bombyx genes. We specify the donor sequence requirements that affected knock-in efficiency, and demonstrate the successful applications of this method of sequence deletion, insertion and replacement in the Bombyx genome.
      Graphical abstract image

      PubDate: 2016-08-27T03:06:29Z
      DOI: 10.1016/j.ibmb.2016.08.006
      Issue No: Vol. 78 (2016)
  • Metabolism of poplar salicinoids by the generalist herbivore Lymantria
           dispar (Lepidoptera)
    • Authors: G. Andreas Boeckler; Christian Paetz; Peter Feibicke; Jonathan Gershenzon; Sybille B. Unsicker
      Pages: 39 - 49
      Abstract: Publication date: Available online 5 August 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): G. Andreas Boeckler, Christian Paetz, Peter Feibicke, Jonathan Gershenzon, Sybille B. Unsicker
      The survival of insect herbivores on chemically defended plants may often depend on their ability to metabolize these defense compounds. However, only little knowledge is available on how insects actually process most plant defense compounds. We investigated the metabolism of salicinoids, a major group of phenolic glycosides in poplar and willow species, by a generalist herbivore, the gypsy moth (Lymantria dispar). Seven salicinoid metabolites identified in gypsy moth caterpillar feces were mostly conjugates with glucose, cysteine or glycine. Two of the glucosides were phosphorylated, a feature not previously reported for insect metabolites of plant defense compounds. The origins of these metabolites were traced to specific moieties of three major poplar salicinoids ingested, salicin, salicortin and tremulacin. Based on the observed metabolite patterns we were able to deduce the initial steps of salicinoid breakdown in L. dispar guts, which involves cleavage of ester bonds. The conjugated molecules were effectively eliminated within 24 h after ingestion. Some of the initial breakdown products (salicin and catechol) demonstrated negative effects on insect growth and survival in bioassays on artificial diets. Gypsy moth caterpillars with prior feeding experience on salicinoid-containing poplar foliage converted salicinoids to the identified metabolites more efficiently than caterpillars pre-fed an artificial diet. The majority of the metabolites we identified were also produced by other common poplar-feeding insects. The conversion of plant defenses like salicinoids to a variety of water-soluble sugar, phosphate and amino acid conjugates and their subsequent excretion fits the general detoxification strategy found in insect herbivores and other animals.
      Graphical abstract image

      PubDate: 2016-08-09T01:40:03Z
      DOI: 10.1016/j.ibmb.2016.08.001
      Issue No: Vol. 78 (2016)
  • Pyriproxyfen is metabolized by P450s associated with pyrethroid resistance
           in An. gambiae
    • Authors: Cristina Yunta; Nelson Grisales; Szilárd Nász; Kay Hemmings; Patricia Pignatelli; Michael Voice; Hilary Ranson; Mark J.I. Paine
      Pages: 50 - 57
      Abstract: Publication date: Available online 7 September 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Cristina Yunta, Nelson Grisales, Szilárd Nász, Kay Hemmings, Patricia Pignatelli, Michael Voice, Hilary Ranson, Mark J.I. Paine
      Pyrethroid resistance is widespread in the malaria vector Anopheles gambiae leading to concerns about the future efficacy of bednets with pyrethroids as the sole active ingredient. The incorporation of pyriproxyfen (PPF), a juvenile hormone analogue, into pyrethroid treated bednets is being trialed in Africa. Pyrethroid resistance is commonly associated with elevated levels of P450 expression including CYPs 6M2, 6P2, 6P3, 6P4, 6P5, 6Z2 and 9J5. Having expressed these P450s in E. coli we find all are capable of metabolizing PPF. Inhibition of these P450s by permethrin, deltamethrin and PPF was also examined. Deltamethrin and permethrin were moderate inhibitors (IC50 1–10 μM) of diethoxyfluorescein (DEF) activity for all P450s apart from CYP6Z2 (IC50 > 10 μM), while PPF displayed weaker inhibition of all P450s (IC50 > 10 μM) except CYP's 6Z2 and 6P2 (IC50 1–10 μM). We found evidence of low levels of cross resistance between PPF and other insecticide classes by comparing the efficacy of PPF in inhibiting metamorphosis and inducing female sterility in an insecticide susceptible strain of An. gambiae and a multiple resistant strain from Cote d’Ivoire.
      Graphical abstract image

      PubDate: 2016-09-11T01:03:59Z
      DOI: 10.1016/j.ibmb.2016.09.001
      Issue No: Vol. 78 (2016)
  • Variation in RNAi efficacy among insect species is attributable to dsRNA
           degradation in vivo
    • Authors: Kangxu Wang; Yingchuan Peng; Jian Pu; Wenxi Fu; Jiale Wang; Zhaojun Han
      Pages: 1 - 9
      Abstract: Publication date: October 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 77
      Author(s): Kangxu Wang, Yingchuan Peng, Jian Pu, Wenxi Fu, Jiale Wang, Zhaojun Han
      RNA interference (RNAi) has become an essential technique in entomology research. However, RNAi efficiency appears to vary significantly among insect species. Here, the sensitivity of four insect species from different orders to RNAi was compared to understand the reason for this variation. A previously reported method was modified to monitor trace amounts of double-stranded RNA (dsRNA). After the administration of dsRNA, the dynamics of its content was determined in the hemolymph, in addition to the capability of its degradation in both the hemolymph and the midgut juice. The results showed that injection of dsRNA targeting the homologous chitinase gene in Periplaneta americana, Zophobas atratus, Locusta migratoria, and Spodoptera litura, with doses (1.0, 2.3, 11.5, and 33.0 μg, respectively) resulting in the same initial hemolymph concentration, caused 82%, 78%, 76%, and 20% depletion, respectively, whereas feeding doses based on body weight (24, 24, 36, and 30 μg) accounted for 47%, 28%, 5%, and 1% depletion. The sensitivity of insects to RNAi was observed to be as follows: P. americana > Z. atratus >> L. migratoria >> S. litura. In vivo monitoring revealed that RNAi effects among these insect species were highly correlated with the hemolymph dsRNA contents. Furthermore, in vitro experiments demonstrated that the hemolymph contents after dsRNA injection were dependent on hemolymph degradation capacities, and on the degradation capabilities in the midgut juice, when dsRNA was fed. In conclusion, the RNAi efficacy in different insect species was observed to depend on the enzymatic degradation of dsRNA, which functions as the key factor determining the inner target exposure dosages. Thus, enzymatic degradation in vivo should be taken into consideration for efficient use of RNAi in insects.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.07.007
      Issue No: Vol. 77 (2016)
  • Functional evaluation of Heat Shock Proteins 70 (HSP70/HSC70) on Rhodnius
           prolixus (Hemiptera, Reduviidae) physiological responses associated with
           feeding and starvation
    • Authors: Rafaela M.M. Paim; Ricardo N. Araujo; Miguel Leis; Mauricio R.V. Sant'anna; Nelder F. Gontijo; Claudio R. Lazzari; Marcos H. Pereira
      Pages: 10 - 20
      Abstract: Publication date: Available online 1 August 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Rafaela M.M. Paim, Ricardo N. Araujo, Miguel Leis, Mauricio R.V. Sant'anna, Nelder F. Gontijo, Claudio Lazzari, Marcos H. Pereira
      Blood-sucking vectors must overcome thermal stress caused by intake of proportionally large amounts of warm blood from their hosts. In response to this, Heat Shock Proteins (HSPs) such as the widely studied HSP70 family (the inducible HSP70 and the cognate form HSC70, known for their role in preserving essential cellular functions) are rapidly up-regulated in their tissues. The triatomine Rhodnius prolixus is an important vector of Trypanosoma cruzi, the causative pathogen of Chagas’ disease, and is also a model organism for studying insect biology and physiology. In this work, we observed that the expression of Rhodnius prolixus HSP70 was rapidly up-regulated in response to thermal shocks (0 °C and 40 °C) and also during the first hours after feeding on blood. HSP70/HSC70 RNAi knockdown elicited important alterations in R. prolixus physiological responses triggered by blood meal and starvation. HSP70/HSC70 knockdown insects showed lower resistance to prolonged starvation in comparison to appropriate controls, dying between 32 and 40 days after dsRNA injection. After blood feeding, the physiological effects of HSP70/HSC70 knockdown were more prominent and the insects died even earlier, within 14–20 days after feeding (21–27 days after dsRNA injection). These bugs showed impaired blood processing and digestion, reduced energetic metabolism and the midgut immune responses were compromised. Our findings suggest that HSP70/HSC70 depletion affected R. prolixus in starvation or fed conditions. After feeding, the arrival of blood in the digestive tract of knockdown insects fails to activate essential signaling pathways involved in blood processing, producing several alterations in their physiological processes enough to generate a premature death.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.07.011
      Issue No: Vol. 77 (2016)
  • Artificial miRNA-mediated silencing of ecdysone receptor (EcR) affects
           larval development and oogenesis in Helicoverpa armigera
    • Authors: Sneha Yogindran; Manchikatla Venkat Rajam
      Pages: 21 - 30
      Abstract: Publication date: Available online 29 July 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Sneha Yogindran, Manchikatla Venkat Rajam
      The insect pests are real threat to farmers as they affect the crop yield to a great extent. The use of chemical pesticides for insect pest control has always been a matter of concern as they pollute the environment and are also harmful for human health. Bt (Bacillus thuringensis) technology helped the farmers to get rid of the insect pests, but experienced a major drawback due to the evolution of insects gaining resistance towards these toxins. Hence, alternative strategies are high on demand to control insect pests. RNA-based gene silencing is emerging as a potential tool to tackle with this problem. In this study, we have shown the use of artificial microRNA (amiRNA) to specifically target the ecdysone receptor (EcR) gene of Helicoverpa armigera (cotton bollworm), which attacks several important crops like cotton, tomato chickpea, pigeon pea, etc and causes huge yield losses. Insect let-7a precursor miRNA (pre-miRNA) backbone was used to replace the native miRNA with that of amiRNA. The precursor backbone carrying the 21 nucleotide amiRNA sequence targeting HaEcR was cloned in bacterial L4440 vector for in vitro insect feeding experiments. Larvae fed with Escherichia coli expressing amiRNA-HaEcR showed a reduction in the expression of target gene as well as genes involved in the ecdysone signaling pathway downstream to EcR and exhibited mortality and developmental defects. Stem-loop RT-PCR revealed the presence of amiRNA in the insect larvae after feeding bacteria expressing amiRNA-HaEcR, which was otherwise absent in controls. We also found a significant drop in the reproduction potential (oogenesis) of moths which emerged from treated larvae as compared to control. These results demonstrate the successful use of an insect pre-miRNA backbone to express amiRNA for gene silencing studies in insects. The method is cost effective and can be exploited as an efficient and alternative tool for insect pest management.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.07.009
      Issue No: Vol. 77 (2016)
  • Overexpression of jumu induces melanotic nodules by activating Toll
           signaling in Drosophila
    • Authors: Gaoqun Zhang; Yangguang Hao; Li Hua Jin
      Pages: 31 - 38
      Abstract: Publication date: Available online 6 August 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Gaoqun Zhang, Yangguang Hao, Li Hua Jin
      Melanotic nodules are commonly assumed to be caused by an abnormal immune response. Several hematopoietic mutants and signaling pathways, including the Toll, JAK/STAT, Ras and JNK pathways, can cause melanotic nodules to develop when specifically activated in hemocytes. Here, we used the UAS-Gal4 system to overexpress jumeaux (jumu) in the fly immune response system. Jumeaux (Jumu) is a new member of the winged-helix/forkhead (WH/FKH) gene family of transcription factors, which plays an important role in the growth and morphogenesis of Drosophila and participates in the proliferation and differentiation of hemocytes. Overexpressing jumu in both hemocytes and the fat body generated many melanotic nodules in larvae and adult flies. The nodules observed in the fat body were surrounded by large numbers of blood cells through a process that appeared similar to foreign body encapsulation. This phenomenon is caused by Toll pathway activation and leads to blood cells deposited in the fat body. In addition, we also report the dissociation of fat cells and the abnormal proliferation and differentiation of blood cells. These results suggest a Jumu-mediated crosstalk between hematopoiesis and the fat body, especially during the Toll-dependent formation of melanotic nodules.
      Graphical abstract image

      PubDate: 2016-08-09T01:40:03Z
      DOI: 10.1016/j.ibmb.2016.08.002
      Issue No: Vol. 77 (2016)
  • Molecular and functional characterization of Bemisia tabaci aquaporins
           reveals the water channel diversity of hemipteran insects
    • Authors: Evelien Van Ekert; François Chauvigné; Roderick Nigel Finn; Lolita G. Mathew; J. Joe Hull; Joan Cerdà; Jeffrey A. Fabrick
      Pages: 39 - 51
      Abstract: Publication date: Available online 2 August 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Evelien van Ekert, François Chauvigné, Roderick Nigel Finn, Lolita G. Mathew, J. Joe Hull, Joan Cerdà, Jeffrey A. Fabrick
      The Middle East-Asia Minor 1 (MEAM1) whitefly, Bemisia tabaci (Gennadius) is an economically important pest of food, fiber, and ornamental crops. This pest has evolved a number of adaptations to overcome physiological challenges, including 1) the ability to regulate osmotic stress between gut lumen and hemolymph after imbibing large quantities of a low nitrogen, sugar-rich liquid diet; 2) the ability to avoid or prevent dehydration and desiccation, particularly during egg hatching and molting; and 3) to be adapted for survival at elevated temperatures. One superfamily of proteins involved in the maintenance of fluid homeostasis in many organisms includes the aquaporins, which are integral membrane channel proteins that aid in the rapid flux of water and other small solutes across biological membranes. Here, we show that B. tabaci has eight aquaporins (BtAqps), of which seven belong to the classical aquaporin 4-related grade of channels, including Bib, Drip, Prip, and Eglps and one that belongs to the unorthodox grade of aquaporin 12-like channels. B. tabaci has further expanded its repertoire of water channels through the expression of three BtDrip2 amino-terminal splice variants, while other hemipteran species express amino- or carboxyl-terminal isoforms of Drip, Prip, and Eglps. Each BtAqp has unique transcript expression profiles, cellular localization, and/or substrate preference. Our phylogenetic and functional data reveal that hemipteran insects lost the classical glp genes, but have compensated for this by duplicating the eglp genes early in their evolution to comprise at least three separate clades of glycerol transporters.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.07.010
      Issue No: Vol. 77 (2016)
  • Physiological roles of trehalose in Leptinotarsa larvae revealed by RNA
           interference of trehalose-6-phosphate synthase and trehalase genes
    • Authors: Ji-Feng Shi; Qing-Yu Xu; Qiang-Kun Sun; Qing-Wei Meng; Li-Li Mu; Wen-Chao Guo; Guo-Qing Li
      Pages: 52 - 68
      Abstract: Publication date: Available online 11 August 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Ji-Feng Shi, Qing-Yu Xu, Qiang-Kun Sun, Qing-Wei Meng, Li-Li Mu, Wen-Chao Guo, Guo-Qing Li
      Trehalose is proposed to serve multiple physiological roles in insects. However, its importance remains largely unconfirmed. In the present paper, we knocked down either a trehalose biosynthesis gene (trehalose-6-phosphate synthase, LdTPS) or each of three degradation genes (soluble trehalases LdTRE1a, LdTRE1b or membrane-bound LdTRE2) in Leptinotarsa decemlineata by RNA interference (RNAi). Knockdown of LdTPS decreased trehalose content and caused larval and pupal lethality. The LdTPS RNAi survivors consumed a greater amount of foliage, obtained a heavier body mass, accumulated more glycogen, lipid and proline, and had a smaller amount of chitin compared with the controls. Ingestion of trehalose but not glucose rescued the food consumption increase and larval mass rise, increased survivorship, and recovered glycogen, lipid and chitin to the normal levels. In contrast, silencing of LdTRE1a increased trehalose content and resulted in larval and pupal lethality. The surviving LdTRE1a RNAi hypomorphs fed a smaller quantity of food, had a lighter body weight, depleted lipid and several glucogenic amino acids, and contained a smaller amount of chitin. Neither trehalose nor glucose ingestion rescued these LdTRE1a RNAi defects. Silencing of LdTRE1b caused little effects. Knockdown of LdTRE2 caused larval death, increased trehalose contents in several tissues and diminished glycogen in the brain-corpora cardiaca-corpora allata complex (BCC). Feeding glucose but not trehalose partially rescued the high mortality rate and recovered glycogen content in the BCC. It seems that trehalose is involved in feeding regulation, sugar absorption, brain energy supply and chitin biosynthesis in L. decemlineata larvae.
      Graphical abstract image

      PubDate: 2016-08-13T02:01:30Z
      DOI: 10.1016/j.ibmb.2016.07.012
      Issue No: Vol. 77 (2016)
  • Determination of juvenile hormone titers by means of LC-MS/MS/MS and a
           juvenile hormone-responsive Gal4/UAS system in Aedes aegypti mosquitoes
    • Authors: Bo Zhao; Yuan Hou; Jianjun Wang; Vladimir A. Kokoza; Tusar T. Saha; Xue-Li Wang; Ling Lin; Zhen Zou; Alexander S. Raikhel
      Pages: 69 - 77
      Abstract: Publication date: Available online 12 August 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Bo Zhao, Yuan Hou, Jianjun Wang, Vladimir A. Kokoza, Tusar T. Saha, Xue-Li Wang, Ling Lin, Zhen Zou, Alexander S. Raikhel
      In anautogenous mosquitoes, juvenile hormone III (JH) plays an essential role in female post-eclosion (PE) development, preparing them for subsequent blood feeding and egg growth. We re-examined the JH titer during the reproductive cycle of female Aedes aegypti mosquitoes. Using liquid chromatography coupled with triple tandem mass spectrometry (LC-MS/MS/MS), we have shown that it reaches its peak at 48–54 h PE in the female hemolymph and at 72 h PE in whole body extracts. This method represents an effective assay for determination of JH titers. The 2.1-kb 5’ promoter region of the Early Trypsin (ET) gene, which is specifically expressed in the female midgut under the control of JH during the PE phase, was utilized to genetically engineer the Ae. aegypti mosquito line with the ET-Gal4 activator. We then established the ET-GAL4>UAS-enhanced green fluorescent protein (EGFP) system in Ae. aegypti. In ET-Gal4>UAS-EGFP female mosquitoes, the intensity of the midgut-specific EGFP signal was observed to correspond to the ET gene transcript level and follow the JH titer during the PE phase. The EGFP signal and the EGFP transcript level were significantly diminished in midguts of transgenic female mosquitoes after RNA interference depletion of the JH receptor Methoprene-tolerant (Met), providing evidence of the control of ET gene expression by Met. Topical JH application caused premature enhancement of the EGFP signal and the EGFP transcript level in midguts of newly eclosed ET-Gal4>UAS-EGFP female mosquitoes, in which endogenous JH titer is still low. Hence, this novel ET-Gal4>UAS system permits JH-dependent gene overexpression in the midgut of Ae. aegypti female mosquitoes prior to a blood meal.
      Graphical abstract image

      PubDate: 2016-08-13T02:01:30Z
      DOI: 10.1016/j.ibmb.2016.08.003
      Issue No: Vol. 77 (2016)
  • Electrophysiological characterization of ivermectin triple actions on
    • Authors: Toshinori Fuse; Tomo Kita; Yunosuke Nakata; Fumiyo Ozoe; Yoshihisa Ozoe
      Pages: 78 - 86
      Abstract: Publication date: Available online 16 August 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Toshinori Fuse, Tomo Kita, Yunosuke Nakata, Fumiyo Ozoe, Yoshihisa Ozoe
      Ivermectin (IVM) is a macrocyclic lactone that exerts antifilarial, antiparasitic, and insecticidal effects on nematodes and insects by acting on L-glutamic acid-gated chloride channels (GluCls). IVM also acts as an allosteric modulator of various other ion channels. Although the IVM binding site in the Caenorhabditis elegans GluCl was identified by X-ray crystallographic analysis, the mechanism of action of IVM in insects is not well defined. We therefore examined the action of IVM on the housefly (Musca domestica) GluCl and γ-aminobutyric acid (GABA)-gated ion channel (GABACl). For both channels, IVM induced currents by itself, potentiated currents induced by low concentrations of agonists, and inhibited currents induced by high concentrations of agonists. Despite exerting common actions on both types of channels, GluCls were more susceptible to IVM actions than GABACls, indicating that GluCls are the primary target of IVM. Substitution of an amino acid residue in the third transmembrane segment (G312M in GluCls, and G333A and G333M in GABACls) resulted in significantly reduced levels or loss of activation, potentiation, and antagonism of the channels, indicating that these three actions result from the interaction of IVM with amino acid residues in the transmembrane intersubunit crevice.
      Graphical abstract image

      PubDate: 2016-08-18T02:27:48Z
      DOI: 10.1016/j.ibmb.2016.08.005
      Issue No: Vol. 77 (2016)
  • In search of a function of Manduca sexta hemolymph protease-1 in the
           innate immune system
    • Authors: Fan Yang; Yang Wang; Yan He; Haobo Jiang
      Pages: 1 - 10
      Abstract: Publication date: September 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 76
      Author(s): Fan Yang, Yang Wang, Yan He, Haobo Jiang
      Extracellular serine protease cascades mediate immune signaling and responses in insects. In the tobacco hornworm Manduca sexta, nearly 30 serine proteases (SPs) and their homologs (SPHs) are cloned from hemocytes and fat body. Some of them participate in prophenoloxidase (proPO) activation and proSpätzle processing. Here we report the cDNA cloning of hemolymph protease-1b (HP1b), which is 90% identical and 95% similar to HP1a (formerly HP1). The HP1a and HP1b mRNA levels in hemocytes was down- and up-regulated after an immune challenge, respectively. Quantitative real-time polymerase chain reactions revealed their tissue-specific and development-dependent expression, mostly in hemocytes of the feeding larvae. We isolated HP1 precursor (proHP1) from larval hemolymph and observed micro-heterogeneity caused by N-linked glycosylation. Supplementation of the purified proHP1 to plasma samples from naïve larvae or induced ones injected with bacteria caused a small PO activity increase, much lower than those elicited by recombinant proHP1a/b, but no proteolytic cleavage was detected in the zymogens. Incubation of proHP1a/b or their catalytic domains with a cationic detergent, cetylpyridinium chloride, induced an amidase activity that hydrolyzed LDLH-p-nitroanilide. Since LDLH corresponds to the P4–P1 region before the proteolytic activation site of proHP6, we propose that the active but uncleaved proHP1 may cut proHP6 to generate HP6 that in turn activates proPAP1 and proHP8. The catalytic domain of HP1a/b, which by itself does not activate purified proHP6 or hydrolyze LDLH-p-nitroanilide, somehow generated active HP6, HP8, PAP1 and PO in plasma. Together, these results indicate that proHP1 participates in the proPO activation system, although detailed mechanism needs further exploration.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.06.009
      Issue No: Vol. 76 (2016)
  • Functional validation of cadherin as a receptor of Bt toxin Cry1Ac in
           Helicoverpa armigera utilizing the CRISPR/Cas9 system
    • Authors: Jing Wang; Haonan Zhang; Huidong Wang; Shan Zhao; Yayun Zuo; Yihua Yang; Yidong Wu
      Pages: 11 - 17
      Abstract: Publication date: September 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 76
      Author(s): Jing Wang, Haonan Zhang, Huidong Wang, Shan Zhao, Yayun Zuo, Yihua Yang, Yidong Wu
      Cadherins have been identified as receptors of Bacillus thuringiensis (Bt) Cry1A toxins in several lepidopteran insects including the cotton bollworm, Helicoverpa armigera. Disruption of the cadherin gene HaCad has been genetically linked to resistance to Bt toxin Cry1Ac in H. armigera. By using the CRISPR/Cas9 genome editing system (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9), HaCad from the Cry1Ac-susceptible SCD strain of H. armigera was successfully knocked out. A single positive CRISPR event with a frame shift deletion of 4 nucleotides was identified and made homozygous to create a knockout line named SCD-Cad. Western blotting confirmed that HaCad was no longer expressed in the SCD-Cad line while an intact HaCad of 210 kDa was present in the parental SCD strain. Insecticide bioassays were used to show that SCD-Cad exhibited 549-fold resistance to Cry1Ac compared with SCD, but no significant change in susceptibility to Cry2Ab. Our results not only provide strong reverse genetics evidence for HaCad as a functional receptor of Cry1Ac, but also demonstrate that the CRISPR/Cas9 technique can act as a powerful and efficient genome editing tool to study gene function in a global agricultural pest, H. armigera.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.06.008
      Issue No: Vol. 76 (2016)
  • Characteristics and expression patterns of histone-modifying enzyme
           systems in the migratory locust
    • Authors: Siyuan Guo; Feng Jiang; Pengcheng Yang; Qing Liu; Xianhui Wang; Le Kang
      Pages: 18 - 28
      Abstract: Publication date: September 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 76
      Author(s): Siyuan Guo, Feng Jiang, Pengcheng Yang, Qing Liu, Xianhui Wang, Le Kang
      The density-dependent phase polyphenism in locusts offers an excellent model to investigate the epigenetic regulatory mechanisms underlying phenotypic plasticity. In this study, we identified histone-modifying enzymes mediating histone post-translational modifications, which serve as a major regulatory mechanism of epigenetic processes, on the basis of the whole genome sequence of the migratory locust, Locusta migratoria. We confirmed the existence of various functional histone modifications in the locusts. Compared with other sequenced insect genomes, the locust genome contains a richer repertoire of histone-modifying enzymes. Several locust histone-modifying enzymes display vertebrate-like characteristics, such as the presence of a Sirt3-like gene and multiple alternative splicing of GCN5 gene. Most histone-modifying enzymes are highly expressed in the eggs or in the testis tissues of male adults. Several histone deacetylases and H3K4-specific methyltransferases exhibit differential expression patterns in brain tissues between solitarious and gregarious locusts. These results reveal the main characteristics of histone-modifying enzymes and provide important cues for understanding the epigenetic mechanisms underlying phase polyphenism in locusts.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.06.010
      Issue No: Vol. 76 (2016)
  • Changes in histone acetylation as potential mediators of pupal diapause in
           the flesh fly, Sarcophaga bullata
    • Authors: J.A. Reynolds; Robin Bautista-Jimenez; D.L. Denlinger
      Pages: 29 - 37
      Abstract: Publication date: September 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 76
      Author(s): J.A. Reynolds, Robin Bautista-Jimenez, D.L. Denlinger
      The growing appreciation that epigenetic processes are integral to the responses of many organisms to changes in the environment suggests a possible role for epigenetics in coordination of insect diapause. The results we present suggest that histone modification may be one type of epigenetic process that contributes to regulation of pupal diapause in the flesh fly, Sarcophaga bullata. Reduction in total histone H3 acetylation in diapausing pupae, shifts in mRNA expression profiles of genes encoding histone acetyltransferase (HAT) and histone deacetylase (HDAC) in pre-diapause, diapause and post-diapause flies compared to their nondiapause counterparts, and alterations in HDAC enzyme activity during and post-diapause lend support to the hypothesis that this specific type of histone modification is involved in regulating diapause programming, maintenance, and termination. Transcription of genes encoding HDAC1, HDAC3, HDAC6, and Sirtuin2 were all upregulated in photosensitive first instar larvae programmed to enter pupal diapause, suggesting that histone deacetylation may be linked to the early decision to enter diapause. A 50% reduction in transcription of hdac3 and a corresponding 30% reduction in HDAC activity during diapause suggest that removal of acetyl groups from histones primarily occurs prior to diapause entry and that further histone deacetylation is not necessary to maintain diapause. Transcription of the HDAC genes was quickly elevated when diapause was terminated, followed by an increase in enzyme activity after a short delay. A maternal effect operating in these flies prevents pupal diapause in progeny whose mothers experienced pupal diapause, even if the progeny are reared in strong diapause-inducing short-day conditions. Such nondiapausing pupae had HDAC transcription profiles nearly identical to the profiles seen in nondiapausing pupae generated under a long-day photoperiod. Together, these results provide consistent evidence for histone acetylation and deacetylation as regulators of this insect's developmental trajectory.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.06.012
      Issue No: Vol. 76 (2016)
  • Dipeptidyl peptidase 4 – An important digestive peptidase in
           Tenebrio molitor larvae
    • Authors: Valeriia F. Tereshchenkova; Irina A. Goptar; Irina A. Kulemzina; Dmitry P. Zhuzhikov; Marina V. Serebryakova; Mikhail A. Belozersky; Yakov E. Dunaevsky; Brenda Oppert; Irina Yu Filippova; Elena N. Elpidina
      Pages: 38 - 48
      Abstract: Publication date: September 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 76
      Author(s): Valeriia F. Tereshchenkova, Irina A. Goptar, Irina A. Kulemzina, Dmitry P. Zhuzhikov, Marina V. Serebryakova, Mikhail A. Belozersky, Yakov E. Dunaevsky, Brenda Oppert, Irina Yu Filippova, Elena N. Elpidina
      Dipeptidyl peptidase 4 (DPP 4) is a proline specific serine peptidase that plays an important role in different regulatory processes in mammals. In this report, we isolated and characterized a unique secreted digestive DPP 4 from the anterior midgut of a stored product pest, Tenebrio molitor larvae (TmDPP 4), with a biological function different than that of the well-studied mammalian DPP 4. The sequence of the purified enzyme was confirmed by mass-spectrometry, and was identical to the translated RNA sequence found in a gut EST database. The purified peptidase was characterized according to its localization in the midgut, and substrate specificity and inhibitor sensitivity were compared with those of human recombinant DPP 4 (rhDPP 4). The T. molitor enzyme was localized mainly in the anterior midgut of the larvae, and 81% of the activity was found in the fraction of soluble gut contents, while human DPP 4 is a membrane enzyme. TmDPP 4 was stable in the pH range 5.0–9.0, with an optimum activity at pH 7.9, similar to human DPP 4. Only specific inhibitors of serine peptidases, diisopropyl fluorophosphate and phenylmethylsulfonyl fluoride, suppressed TmDPP 4 activity, and the specific dipeptidyl peptidase inhibitor vildagliptin was most potent. The highest rate of TmDPP 4 hydrolysis was found for the synthetic substrate Arg-Pro-pNA, while Ala-Pro-pNA was a better substrate for rhDPP 4. Related to its function in the insect midgut, TmDPP 4 efficiently hydrolyzed the wheat storage proteins gliadins, which are major dietary proteins of T. molitor.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.07.003
      Issue No: Vol. 76 (2016)
  • Identification of major Toxoneuron nigriceps venom proteins using an
           integrated transcriptomic/proteomic approach
    • Authors: Simona Laurino; Gerarda Grossi; Pietro Pucci; Angela Flagiello; Sabino Aurelio Bufo; Giuliana Bianco; Rosanna Salvia; S. Bradleigh Vinson; Heiko Vogel; Patrizia Falabella
      Pages: 49 - 61
      Abstract: Publication date: September 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 76
      Author(s): Simona Laurino, Gerarda Grossi, Pietro Pucci, Angela Flagiello, Sabino Aurelio Bufo, Giuliana Bianco, Rosanna Salvia, S. Bradleigh Vinson, Heiko Vogel, Patrizia Falabella
      Endoparasitoids in the order Hymenoptera are natural enemies of several herbivorous insect pest species. During oviposition they inject a mixture of factors, which include venom, into the host, ensuring the successful parasitism and the development of their progeny. Although these parasitoid factors are known to be responsible for host manipulation, such as immune system suppression, little is known about both identity and function of the majority of their venom components. To identify the major proteins of Toxoneuron nigriceps (Hymenoptera: Braconidae) venom, we used an integrated transcriptomic and proteomic approach. The tandem-mass spectrometric (LC-MS/MS) data combined with T. nigriceps venom gland transcriptome used as a reference database resulted in the identification of a total of thirty one different proteins. While some of the identified proteins have been described in venom from several parasitoids, others were identified for the first time. Among the identified proteins, hydrolases constituted the most abundant family followed by transferases, oxidoreductases, ligases, lyases and isomerases. The hydrolases identified in the T. nigriceps venom glands included proteases, peptidases and glycosidases, reported as common components of venom from several parasitoid species. Taken together, the identified proteins included factors that could potentially inhibit the host immune system, manipulate host physiological processes and host development, as well as provide nutrients to the parasitoid progeny, degrading host tissues by specific hydrolytic enzymes. The venom decoding provides us with information about the identity of candidate venom factors which could contribute to the success of parasitism, together with other maternal and embryonic factors.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.07.001
      Issue No: Vol. 76 (2016)
  • Ingestion of the epoxide hydrolase inhibitor AUDA modulates immune
           responses of the mosquito, Culex quinquefasciatus during blood feeding
    • Authors: Jiawen Xu; Christophe Morisseau; Jun Yang; Kin Sing Stephen Lee; Shizuo G. Kamita; Bruce D. Hammock
      Pages: 62 - 69
      Abstract: Publication date: September 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 76
      Author(s): Jiawen Xu, Christophe Morisseau, Jun Yang, Kin Sing Stephen Lee, Shizuo G. Kamita, Bruce D. Hammock
      Epoxide hydrolases (EHs) are enzymes that play roles in metabolizing xenobiotic epoxides from the environment, and in regulating lipid signaling molecules, such as juvenile hormones in insects and epoxy fatty acids in mammals. In this study we fed mosquitoes with an epoxide hydrolase inhibitor AUDA during artificial blood feeding, and we found the inhibitor increased the concentration of epoxy fatty acids in the midgut of female mosquitoes. We also observed ingestion of AUDA triggered early expression of defensin A, cecropin A and cecropin B2 at 6 h after blood feeding. The expression of cecropin B1 and gambicin were not changed more than two fold compared to controls. The changes in gene expression were transient possibly because more than 99% of the inhibitor was metabolized or excreted at 42 h after being ingested. The ingestion of AUDA also affected the growth of bacteria colonizing in the midgut, but did not affect mosquito longevity, fecundity and fertility in our laboratory conditions. When spiked into the blood, EpOMEs and DiHOMEs were as effective as the inhibitor AUDA in reducing the bacterial load in the midgut, while EETs rescued the effects of AUDA. Our data suggest that epoxy fatty acids from host blood are immune response regulators metabolized by epoxide hydrolases in the midgut of female mosquitoes, inhibition of which causes transient changes in immune responses, and affects growth of microbes in the midgut.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.06.011
      Issue No: Vol. 76 (2016)
  • Apoptosis-related genes control autophagy and influence DENV-2 infection
           in the mosquito vector, Aedes aegypti
    • Authors: Matthew W. Eng; Madeleine N. van Zuylen; David W. Severson
      Pages: 70 - 83
      Abstract: Publication date: September 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 76
      Author(s): Matthew W. Eng, Madeleine N. van Zuylen, David W. Severson
      The mosquito Aedes aegypti is the primary urban vector for dengue virus (DENV) worldwide. Insight into interactions occurring between host and pathogen is important in understanding what factors contribute to vector competence. However, many of the molecular mechanisms for vector competence remain unknown. Our previous global transcriptional analysis suggested that differential expression of apoptotic proteins is involved in determining refractoriness vs susceptibility to DENV-2 infection in Ae. aegypti females following a DENV-infected blood meal. To determine whether DENV-refractory Ae. aegypti showed more robust apoptosis upon infection, we compared numbers of apoptotic cells from midguts of refractory and susceptible strains and observed increased numbers of apoptotic cells in only the refractory strain upon DENV-2 infection. Thereafter, we manipulated apoptosis through dsRNA interference of the initiator caspase, Aedronc. Unexpectedly, dsAedronc-treated females showed both decreased frequency of disseminated infection and decreased virus titer in infected individuals. Insect caspases have also previously been identified as regulators of the cellular recycling process known as autophagy. We observed activation of autophagy in midgut and fat body tissues following a blood meal, as well as programmed activation of several apoptosis-related genes, including the effector caspase, Casps7. To determine whether autophagy was affected by caspase knockdown, we silenced Aedronc and Casps7, and observed reduced activation of autophagy upon silencing. Our results provide evidence that apoptosis-related genes are also involved in regulating autophagy, and that Aedronc may play an important role in DENV-2 infection success in Ae. aegypti, possibly through its regulation of autophagy.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.07.004
      Issue No: Vol. 76 (2016)
  • Cytochrome P450 gene, CYP4G51, modulates hydrocarbon production in the pea
           aphid, Acyrthosiphon pisum
    • Authors: Nan Chen; Yong-Liang Fan; Yu Bai; Xiang-dong Li; Zhan-Feng Zhang; Tong-Xian Liu
      Pages: 84 - 94
      Abstract: Publication date: September 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 76
      Author(s): Nan Chen, Yong-Liang Fan, Yu Bai, Xiang-dong Li, Zhan-Feng Zhang, Tong-Xian Liu
      Terrestrial insects deposit a layer of hydrocarbons (HCs) as waterproofing agents on their epicuticle. The insect-specific CYP4G genes, subfamily members of P450, have been found in all insects with sequenced genomes to date. They are critical for HC biosynthesis in Drosophila; however, their functional roles in other insects including the piercing-sucking hemipterous aphids remain unknown. In this study, we presented the molecular characterization and a functional study of the CYP4G51 gene in the pea aphid, Acyrthosiphon pisum (Harris). CYP4G51 transcript was detectable across the whole life cycle of A. pisum, and was prominently expressed in the aphid head and abdominal cuticle. Up-regulation of CYP4G51 under desiccation stress was more significant in the third instar nymphs compared with the adults. Also, up-regulation of CYP4G51 was observed when the aphids fed on an artificial diet compared with those fed on the broad bean plant, and was positively correlated with a high level of cuticular HCs (CHCs). RNAi knockdown of CYP4G51 significantly reduced its expression and caused reductions in both internal and external HCs. A deficiency in CHCs resulted in aphids being more susceptible to desiccation, with increased mortality under desiccation stress. The current results confirm that CYP4G51 modulates HC biosynthesis to protect aphids from desiccation. Moreover, our data also indicate that saturated and straight-chain HCs play a major role in cuticular waterproofing in the pea aphid. A. pisum CYP4G51 could be considered as a novel RNAi target in the field of insect pest management.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.07.006
      Issue No: Vol. 76 (2016)
  • Histomorphometric and transcriptomic features characterize silk glands'
           development during the molt to intermolt transition process in silkworm
    • Authors: Wenbo Hu; Chun Liu; Tingcai Cheng; Wei Li; Niannian Wang; Qingyou Xia
      Pages: 95 - 108
      Abstract: Publication date: September 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 76
      Author(s): Wenbo Hu, Chun Liu, Tingcai Cheng, Wei Li, Niannian Wang, Qingyou Xia
      The molt–intermolt cycle is an essential feature in holometabolous and hemimetabolous insects' development. In the silkworm, silk glands are under dramatic morphological and functional changes with fibroin genes' transcription being repeatedly turned off and on during the molt–intermolt cycles. However, the molecular mechanisms controlling it are still unknown. Here, silk gland's histomorphology and transcriptome analysis were used to characterize changes in its structure and gene expression patterns from molt to intermolt stages. By using section staining and transmission electron microscope, a renewable cell damage was detected in the silk gland at the molt stage, and an increased number of autophagosomes and lysosomes were found in silk gland cells' cytoplasm. Next, by using RNA sequencing, 54,578,413 reads were obtained, of which 85% were mapped to the silkworm reference genome. The expression level analysis of silk protein genes and silk gland transcription factors revealed that fibroin heavy chain, fibroin light chain, P25/fhx, sericin1, sericin3 and Dimm had consistent alteration trends in temporal expression. In addition, differentially expressed genes (DEGs) were identified, and most of the DEGs associated with ecdysone signal transduction, mRNA degradation, protein proteolysis, and autophagy were significantly down-regulated in the transition from molt to intermolt, suggesting that these pathways were activated for the silk gland renewal. These findings provide insights into the molecular mechanisms of silk gland development and silk protein genes transcriptional regulation during the molt to intermolt transition process.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.07.002
      Issue No: Vol. 76 (2016)
  • Three toxins, two receptors, one mechanism: Mode of action of Cry1A toxins
           from Bacillus thuringiensis in Heliothis virescens
    • Authors: Anne Bretschneider; David G. Heckel; Yannick Pauchet
      Pages: 109 - 117
      Abstract: Publication date: September 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 76
      Author(s): Anne Bretschneider, David G. Heckel, Yannick Pauchet
      Insecticidal crystal (Cry) proteins from Bacillus thuringiensis (Bt) are highly active against Lepidoptera. However, field-evolved resistance to Bt toxins is on the rise. The 12-cadherin domain protein HevCaLP and the ABC transporter HevABCC2 are both genetically linked to Cry toxin resistance in Heliothis virescens. We investigated their interaction using stably expressing non-lytic clonal Sf9 cell lines expressing either protein or both together. Untransfected Sf9 cells are innately sensitive to Cry1Ca toxin, but not to Cry1A toxins; and quantitative PCR revealed negligible expression of genes involved in Cry1A toxicity such as cadherin, ABCC2, alkaline phosphatase (ALP) and aminopeptidase N (APN). Cry1Aa, Cry1Ab or Cry1Ac caused swelling of Sf9 cells expressing HevABCC2, and caused faster swelling, lysis and up to 86% mortality in cells expressing both proteins. No such effect was observed in control Sf9 cells or in cells expressing only HevCaLP. The results of a mixing experiment demonstrated that both proteins need to be expressed within the same cell for high cytotoxicity, and suggest a novel role for HevCaLP. Binding assays showed that the toxin-receptor interaction is specific. Our findings confirm that HevABCC2 is the central target in Cry1A toxin mode of action, and that HevCaLP plays a supporting role in increasing Cry1A toxicity.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.07.008
      Issue No: Vol. 76 (2016)
  • Functional characterization of SlitPBP3 in Spodoptera litura by
           CRISPR/Cas9 mediated genome editing
    • Authors: Guan-Heng Zhu; Jun Xu; Zhen Cui; Xiao-Tong Dong; Zhan-Feng Ye; Dong-Juan Niu; Yong-Ping Huang; Shuang-Lin Dong
      Pages: 1 - 9
      Abstract: Publication date: Available online 15 May 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Guan-Heng Zhu, Jun Xu, Zhen Cui, Xiao-Tong Dong, Zhan-Feng Ye, Dong-Juan Niu, Yong-Ping Huang, Shuang-Lin Dong
      Functional gene analysis by using genome editing techniques is limited only in few model insects. Here, we reported an efficient and heritable gene mutagenesis analysis in an important lepidopteran pest, Spodoptera litura, using the CRISPR/Cas9 system. By using this system, we successfully obtained the homozygous S. litura strain by targeting the pheromone binding protein 3 gene (SlitPBP3), which allowed us to elucidate the role of this gene in the olfaction of the female sex pheromones. By co-injection of Cas9 mRNA and sgRNA into S. litura eggs, highly efficient chimera mutation in SlitPBP3 loci was detected both in injected eggs (39.1%) and in the resulted individual moths (87.5%). We used the mutant moths as parents to obtain the G1 offspring and the homozygous mutant strain in G2. The function of SlitPBP3 was explored by Electroantennogram (EAG) recordings with a homozygous mutant strain. The result showed that the EAG responses were significantly decreased in mutant males than in control males when treated with the major sex pheromone component (Z9,E11-14:Ac) and a minor component (Z9-14:Ac) at higher dosages. The results demonstrate that s SlitPBP3 gene plays a minor role in the perception of the female sex pheromones. Furthermore, our study provides a useful methodology with the CRISPR/Cas9 system for gene in vivo functional study, particular for lepidopteran species in which the RNAi approach is not efficient.
      Graphical abstract image

      PubDate: 2016-05-16T02:14:48Z
      DOI: 10.1016/j.ibmb.2016.05.006
      Issue No: Vol. 75 (2016)
  • Ecdysteroid signalling components in metamorphosis and development of the
           desert locust, Schistocerca gregaria
    • Authors: Cynthia Lenaerts; Pieter Van Wielendaele; Paulien Peeters; Jozef Vanden Broeck; Elisabeth Marchal
      Pages: 10 - 23
      Abstract: Publication date: Available online 13 May 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Cynthia Lenaerts, Pieter Van Wielendaele, Paulien Peeters, Jozef Vanden Broeck, Elisabeth Marchal
      The arthropod-specific hormone family of ecdysteroids plays an important role in regulating diverse physiological processes, such as moulting and metamorphosis, reproduction, diapause and innate immunity. Ecdysteroids mediate their response by binding to a heterodimeric complex of two nuclear receptors, the ecdysone receptor (EcR) and the retinoid-X-receptor/ultraspiracle (RXR/USP). In this study we investigated the role of EcR and RXR in metamorphosis and development of the desert locust, Schistocerca gregaria. The desert locust is a voracious, phytophagous, swarming pest that can ruin crops and harvests in some of the world's poorest countries. A profound knowledge of the ecdysteroid signalling pathway can be used in the development of more target-specific insecticides to combat this harmful plague insect. Here we report an in-depth profiling study of the transcript levels of EcR and RXR, as well as its downstream response genes, in different tissues isolated throughout the last larval stage of a hemimetabolous insect, showing a clear correlation with circulating ecdysteroid titres. Using RNA interference (RNAi), the role of SgEcR/SgRXR in moulting and development was investigated. We have proven the importance of the receptor components for successful moulting of locust nymphs into the adult stage. Some SgEcR/SgRXR knockdown females were arrested in the last larval stage, and 65% of them initiated vitellogenesis and oocyte maturation, which normally only occurs in adults. Furthermore, our results clearly indicate that at the peak of ecdysteroid synthesis, on day six of the last larval stage, knockdown of SgEcR/SgRXR is affecting the transcript levels of the Halloween genes, Spook, Shadow and Shade.
      Graphical abstract image

      PubDate: 2016-05-16T02:14:48Z
      DOI: 10.1016/j.ibmb.2016.05.003
      Issue No: Vol. 75 (2016)
  • Structure, evolution, and expression of antimicrobial silk proteins,
           seroins in Lepidoptera
    • Authors: Zhaoming Dong; Qianru Song; Yan Zhang; Shiyi Chen; Xiaolu Zhang; Ping Zhao; Qingyou Xia
      Pages: 24 - 31
      Abstract: Publication date: Available online 13 May 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Zhaoming Dong, Qianru Song, Yan Zhang, Shiyi Chen, Xiaolu Zhang, Ping Zhao, Qingyou Xia
      The silks of silkworm and waxworm contain abundant antimicrobial proteins, including protease inhibitors and seroins. Protease inhibitors have antifungal activities, whereas seroins have antiviral and antibacterial activities. In order to obtain insights into the structure, evolution, and expression of seroins, we performed an extensive survey based on the available genome, transcriptome, and expressed sequence tags datasets. Sixty-four seroins were identified in 32 lepidopteran species. The phylogenetic and structural analyses revealed that seroins can be classified into five subfamilies: seroin 1, seroin 2, seroin 3, seroin 2 + 1, and seroin 3 + 3. It is interesting that seroin 2 + 1 contains two tandem seroin domains, seroin 2 and seroin 1, whereas seroin 3 + 3 has two tandem seroin 3 domains. Each seroin domain contains a proline-rich N-terminal motif and a conserved C-terminal motif. The transcriptome and EST data indicated that seroin 1 and seroin 2 genes were expressed in the silk gland but seroin 3 genes were not. Semi-quantitative RT–PCR and western blot analyses suggested that seroin 1 and seroin 2 were constantly accumulated in the silk gland of silkworm during the fifth instar, and then secreted into cocoon silk during spinning. Immunofluorescence analyses indicated that seroin 1 was secreted into the fibroin and sericin layers, whereas seroin 2 protein was only secreted into the sericin layer. However, the antimicrobial activity of seroin 2 was more effective than that of seroin 1. The presence of seroin 1 in the fibroin layer suggested that this protein not only acts as an antimicrobial protein, but might also play a role in the assembly and secretion of fibroins. Seroin 3, which was first identified here, might be related to pheromone synthesis or recognition, as it was highly expressed in male antennae and in the pheromone gland.
      Graphical abstract image

      PubDate: 2016-05-16T02:14:48Z
      DOI: 10.1016/j.ibmb.2016.05.005
      Issue No: Vol. 75 (2016)
  • Role of Bmznf-2, a Bombyx mori CCCH zinc finger gene, in masculinisation
           and differential splicing of Bmtra-2
    • Authors: Gajula Gopinath; Kallare P. Arunkumar; Kazuei Mita; Javaregowda Nagaraju
      Pages: 32 - 44
      Abstract: Publication date: Available online 1 June 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Gajula Gopinath, Kallare P. Arunkumar, Kazuei Mita, Javaregowda Nagaraju
      Deciphering the regulatory factors involved in Bombyx mori sex determination has been a puzzle, challenging researchers for nearly a century now. The pre-mRNA of B. mori doublesex (Bmdsx), a master regulator gene of sexual differentiation, is differentially spliced, producing Bmdsxm and Bmdsxf transcripts in males and females respectively. The putative proteins encoded by these differential transcripts orchestrate antagonistic functions, which lead to sexual differentiation. A recent study in B. mori illustrated the role of a W-derived fem piRNA in conferring femaleness. In females, the fem piRNA was shown to suppress the activity of a Z-linked CCCH type zinc finger (znf) gene, Masculiniser (masc), which indirectly promotes the Bmdsxm type of splicing. In this study, we report a novel autosomal (Chr 25) CCCH type znf motif encoding gene Bmznf-2 as one of the potential factors in the Bmdsx sex specific differential splicing, and we also provide insights into its role in the alternative splicing of Bmtra2 by using ovary derived BmN cells. Over-expression of Bmznf-2 induced Bmdsxm type of splicing (masculinisation) with a correspondingly reduced expression of Bmdsxf type isoform in BmN cells. Further, the site-directed mutational studies targeting the tandem CCCH znf motifs revealed their indispensability in the observed phenotype of masculinisation. Additionally, the dual luciferase assays in BmN cells using 5′ UTR region of the Bmznf-2 strongly implied the existence of a translational repression over this gene. From these findings, we propose Bmznf-2 to be one of the potential factors of masculinisation similar to Masc. From the growing number of Bmdsx splicing regulators, we assume that the sex determination cascade of B. mori is quite intricate in nature; hence, it has to be further investigated for its comprehensive understanding.
      Graphical abstract image

      PubDate: 2016-06-05T03:18:59Z
      DOI: 10.1016/j.ibmb.2016.05.008
      Issue No: Vol. 75 (2016)
  • Distribution of cuticular proteins in different structures of adult
           Anopheles gambiae
    • Authors: Yihong Zhou; Majors J. Badgett; John Hunter Bowen; Laura Vannini; Ron Orlando; Judith H. Willis
      Pages: 45 - 57
      Abstract: Publication date: Available online 12 May 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yihong Zhou, Majors J. Badgett, John Hunter Bowen, Laura Vannini, Ron Orlando, Judith H. Willis
      Anopheles gambiae devotes over 2% (295) of its protein coding genes to structural cuticular proteins (CPs) that have been classified into 13 different families plus ten low complexity proteins not assigned to families. Small groups of genes code for identical proteins reducing the total number of unique cuticular proteins to 282. Is the large number because different structures utilize different CPs, or are all of the genes widely expressed? We used LC-MS/MS to learn how many products of these genes were found in five adult structures: Johnston's organs, the remainder of the male antennae, eye lenses, legs, and wings. Data were analyzed against both the entire proteome and a smaller database of just CPs. We recovered unique peptides for 97 CPs and shared peptides for another 35. Members of 11 of the 13 families were recovered as well as some unclassified. Only 11 CPs were present exclusively in only one structure while 43 CPs were recovered from all five structures. A quantitative analysis, using normalized spectral counts, revealed that only a few CPs were abundant in each structure. When the MS/MS data were run against the entire proteome, the majority of the top hits were to CPs, but peptides were recovered from an additional 467 proteins. CP peptides were frequently recovered from chitin-binding domains, confirming that protein-chitin interactions are not mediated by covalent bonds. Comparison with three other MS/MS analyses of cuticles or cuticle-rich structures augmented the current analysis. Our findings provide new insights into the composition of different mosquito structures and reveal the complexity of selection and utilization of genes coding for structural cuticular proteins.
      Graphical abstract image

      PubDate: 2016-05-16T02:14:48Z
      DOI: 10.1016/j.ibmb.2016.05.001
      Issue No: Vol. 75 (2016)
  • Expression of the fructose receptor BmGr9 and its involvement in the
           promotion of feeding, suggested by its co-expression with neuropeptide F1
           in Bombyx mori
    • Authors: Dingze Mang; Min Shu; Shiho Tanaka; Shinji Nagata; Tomoyuki Takada; Haruka Endo; Shingo Kikuta; Hiroko Tabunoki; Kikuo Iwabuchi; Ryoichi Sato
      Pages: 58 - 69
      Abstract: Publication date: Available online 7 June 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Dingze Mang, Min Shu, Shiho Tanaka, Shinji Nagata, Tomoyuki Takada, Haruka Endo, Shingo Kikuta, Hiroko Tabunoki, Kikuo Iwabuchi, Ryoichi Sato
      Insect gustatory receptors (Grs) are members of a large family of proteins with seven transmembrane domains that provide insects with the ability to detect chemical signals critical for feeding, mating, and oviposition. To date, 69 Bombyx mori Grs (BmGrs) genes have been identified via genome studies. BmGr9 has been shown to respond specifically to fructose and to function as a ligand-gated ion channel selectively activated by fructose. However, the sites where this Gr are expressed remain unclear. We demonstrated using reverse transcription (RT)-PCR that BmGr9 is widely expressed in the central nervous system (CNS), as well as oral sensory organs. Additionally, immunohistochemistry was performed using anti-BmGr9 antiserum to show that BmGr9 is expressed in cells of the oral sensory organs, including the maxillary galea, maxillary palps, labrum, and labium, as well as in putative neurosecretory cells of the CNS. Furthermore, double immunohistochemical analysis showed that most BmGr9-expressing cells co-localized with putative neuropeptide F1-expressing cells in the brain, suggesting that BmGr9 is involved in the promotion of feeding behaviors. In addition, a portion of BmGr9-expressing cells in the brain co-localized with cells expressing BmGr6, a molecule of the sugar receptor clade, suggesting that sugars other than fructose are involved in the regulation of feeding behaviors in B. mori larvae.
      Graphical abstract image

      PubDate: 2016-06-10T03:45:18Z
      DOI: 10.1016/j.ibmb.2016.06.001
      Issue No: Vol. 75 (2016)
  • A single amino-acid substitution toggles chloride dependence of the
           alpha-amylase paralog amyrel in Drosophila melanogaster and virilis
    • Authors: Gaëlle Claisse; Georges Feller; Magalie Bonneau; Jean-Luc Da Lage
      Pages: 70 - 77
      Abstract: Publication date: Available online 14 June 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Gaëlle Claisse, Georges Feller, Magalie Bonneau, Jean-Luc Da Lage
      In animals, most α-amylases are chloride-dependent enzymes. A chloride ion is required for allosteric activation and is coordinated by one asparagine and two arginine side chains. Whereas the asparagine and one arginine are strictly conserved, the main chloride binding arginine is replaced by a glutamine in some rare instances, resulting in the loss of chloride binding and activation. Amyrel is a distant paralogue of α-amylase in Diptera, which was not characterized biochemically to date. Amyrel shows both substitutions depending on the species. In Drosophila melanogaster, an arginine is present in the sequence but in D. virilis, a glutamine occurs at this position. We have investigated basic enzymological parameters and the dependence to chloride of Amyrel of both species, produced in yeast, and in mutants substituting arginine to glutamine or glutamine to arginine. We found that the amylolytic activity of Amyrel is about thirty times weaker than the classical Drosophila α-amylase, and that the substitution of the arginine by a glutamine in D. melanogaster suppressed the chloride-dependence but was detrimental to activity. In contrast, changing the glutamine into an arginine rendered D. virilis Amyrel chloride-dependent, and interestingly, significantly increased its catalytic efficiency. These results show that the chloride ion is not mandatory for Amyrel but stimulates the reaction rate. The possible phylogenetic origin of the arginine/glutamine substitution is also discussed.
      Graphical abstract image

      PubDate: 2016-06-15T11:59:27Z
      DOI: 10.1016/j.ibmb.2016.06.003
      Issue No: Vol. 75 (2016)
  • Agonist-mediated activation of Bombyx mori diapause hormone receptor
           signals to extracellular signal-regulated kinases 1 and 2 through
           Gq-PLC-PKC-dependent cascade
    • Authors: Xue Jiang; Jingwen Yang; Zhangfei Shen; Yajie Chen; Liangen Shi; Naiming Zhou
      Pages: 78 - 88
      Abstract: Publication date: Available online 16 June 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Xue Jiang, Jingwen Yang, Zhangfei Shen, Yajie Chen, Liangen Shi, Naiming Zhou
      Diapause is a developmental strategy adopted by insects to survive in challenging environments such as the low temperatures of a winter. This unique process is regulated by diapause hormone (DH), which is a neuropeptide hormone that induces egg diapause in Bombyx mori and is involved in terminating pupal diapause in heliothis moths. An G protein-coupled receptor from the silkworm, B. mori, has been identified as a specific cell surface receptor for DH. However, the detailed information on the DH-DHR system and its mechanism(s) involved in the induction of embryonic diapause remains unknown. Here, we combined functional assays with various specific inhibitors to elucidate the DHR-mediated signaling pathways. Upon activation by DH, B. mori DHR is coupled to the Gq protein, leading to a significant increase of intracellular Ca2+ and cAMP response element-driven luciferase activity in an UBO-QIC, a specific Gq inhibitor, sensitive manner. B. mori DHR elicited ERK1/2 phosphorylation in a dose- and time-dependent manner in response to DH. This effect was almost completely inhibited by co-incubation with UBO-QIC and was also significantly suppressed by PLC inhibitor U73122, PKC inhibitors Gö6983 and the Ca2+ chelator EGTA. Moreover, DHR-induced activation of ERK1/2 was significantly attenuated by treatment with the Gβγ specific inhibitors gallein and M119K and the PI3K specific inhibitor Wortmannin, but not by the Src specific inhibitor PP2. Our data also demonstrates that the EGFR-transactivation pathway is not involved in the DHR-mediated ERK1/2 phosphorylation. Future efforts are needed to clarify the role of the ERK1/2 signaling pathway in the DH-mediated induction of B. mori embryonic diapause.
      Graphical abstract image

      PubDate: 2016-06-18T18:04:08Z
      DOI: 10.1016/j.ibmb.2016.06.005
      Issue No: Vol. 75 (2016)
  • Reduced abundance of the CYP6CY3- targeting let-7 and miR-100 miRNAs
           accounts for host adaptation of Myzus persicae nicotianae
    • Authors: Tianfei Peng; Yiou Pan; Xiwu Gao; Jinghui Xi; Lei Zhang; Kangsheng Ma; Yongqiang Wu; Juhong Zhang; Qingli Shang
      Pages: 89 - 97
      Abstract: Publication date: Available online 16 June 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Tianfei Peng, Yiou Pan, Xiwu Gao, Jinghui Xi, Lei Zhang, Kangsheng Ma, Yongqiang Wu, Juhong Zhang, Qingli Shang
      Nicotine is one of the most abundant and toxic secondary plant metabolites in nature and is defined by high toxicity to plant-feeding insects. Studies suggest that increased expression of cytochrome P450 (CYP6CY3) and the homologous CYP6CY4 genes in Myzus persicae nicotianae is correlated with tolerance to nicotine. Indeed, through expression analyses of the CYP6CY3 and CYP6CY4 genes of different M. persicae subspecies, we determined that the mRNA levels of these two genes were much higher in M. persicae nicotianae than in M. persicae sensu stricto. We hypothesized that the expression of these two genes is subject to post-transcriptional regulation. To investigate the underlying mechanism, the miRNA profile of M. persicae nicotianae was sequenced, and twenty-two miRNAs were predicted to target CYP6CY3. Validation of these miRNAs identified two miRNAs, let-7 and miR-100, whose abundance was highly inversely correlated with the abundance of the CYP6CY3 gene. This result implies that the let-7 and miR-100 miRNAs play a major role in the post-transcriptional regulation of the CYP6CY3 gene. Modulation of the abundance of let-7 and miR-100 through the addition of inhibitors/mimics of let-7 or miR-100 to artificial diet significantly altered the tolerance of M. persicae nicotianae to nicotine, further confirming the regulatory role of these two miRNAs. Interestingly, after decreasing the transcript levels of CYP6CY3 by modulating regulatory miRNAs, the transcript levels of the homologous isozyme CYP6CY4 were significantly elevated, suggesting a compensatory mechanism between the CYP6CY3 gene and its homologous CYP6CY4 gene. Our findings provide insight into the molecular drivers of insect host shifts and reveal an important source of genetic variation for adaptive evolution in insect species.
      Graphical abstract image

      PubDate: 2016-06-18T18:04:08Z
      DOI: 10.1016/j.ibmb.2016.06.002
      Issue No: Vol. 75 (2016)
  • CRISPR/Cas9 mediated knockout of the abdominal-A homeotic gene in the
           global pest, diamondback moth (Plutella xylostella)
    • Authors: Yuping Huang; Yazhou Chen; Baosheng Zeng; Yajun Wang; Anthony A. James; Geoff M. Gurr; Guang Yang; Xijian Lin; Yongping Huang; Minsheng You
      Pages: 98 - 106
      Abstract: Publication date: Available online 16 June 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yuping Huang, Yazhou Chen, Baosheng Zeng, Yajun Wang, Anthony A. James, Geoff M. Gurr, Guang Yang, Xijian Lin, Yongping Huang, Minsheng You
      The diamondback moth, Plutella xylostella (L.), is a worldwide agricultural pest that has developed resistance to multiple classes of insecticides. Genetics-based approaches show promise as alternative pest management approaches but require functional studies to identify suitable gene targets. Here we use the CRISPR/Cas9 system to target a gene, abdominal-A, which has an important role in determining the identity and functionality of abdominal segments. We report that P. xylostella abdominal-A (Pxabd-A) has two structurally-similar splice isoforms (A and B) that differ only in the length of exon II, with 15 additional nucleotides in isoform A. Pxabd-A transcripts were detected in all developmental stages, and particularly in pupae and adults. CRISPR/Cas9-based mutagenesis of Pxabd-A exon I produced 91% chimeric mutants following injection of 448 eggs. Phenotypes with abnormal prolegs and malformed segments were visible in hatched larvae and unhatched embryos, and various defects were inherited by the next generation (G1). Genotyping of mutants demonstrated several mutations at the Pxabd-A genomic locus. The results indicate that a series of insertions and deletions were induced in the Pxabd-A locus, not only in G0 survivors but also in G1 individuals, and this provides a foundation for genome editing. Our study demonstrates the utility of the CRISPR/Cas9 system for targeting genes in an agricultural pest and therefore provides a foundation the development of novel pest management tools.
      Graphical abstract image

      PubDate: 2016-06-18T18:04:08Z
      DOI: 10.1016/j.ibmb.2016.06.004
      Issue No: Vol. 75 (2016)
  • Molecular identification of three novel glutaredoxin genes that play
           important roles in antioxidant defense in Helicoverpa armigera
    • Authors: Song-Dou Zhang; Zhong-Jian Shen; Xiao-Ming Liu; Zhen Li; Qing-Wen Zhang; Xiao-Xia Liu
      Pages: 107 - 116
      Abstract: Publication date: August 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 75
      Author(s): Song-Dou Zhang, Zhong-Jian Shen, Xiao-Ming Liu, Zhen Li, Qing-Wen Zhang, Xiao-Xia Liu
      Glutaredoxins (Grxs), also known as thioltransferases, play key roles in maintaining intracellular redox balance and protecting cells from oxidative damage in plants and mammals. We tested whether Grxs play important roles in antioxidant defense in insects using the moth, Helicoverpa armigera. We obtained the full-length cDNA sequences of three novel Grx genes, named HaGrx, HaGrx3, and HaGrx5. Sequence analysis indicated that HaGrx shared a high amino acid identity (58%–78%) and a CPYC motif of conserved redox activity with homologues from other selected insect species. In contrast, HaGrx3 and HaGrx5 both shared a CGF(S/G) motif, a conserved catalytic domain, with other orthologous genes. Quantitative real-time PCR results revealed that HaGrx, HaGrx3, and HaGrx5 exhibited temporally- and spatially-dependent patterns of expression. The mRNA expression of HaGrx, HaGrx3, and HaGrx5 was induced by various temperature stresses and H2O2 treatments. We further investigated the knockdown of HaGrx, HaGrx3, and HaGrx5 in H. armigera larvae and found that most of the selected antioxidant genes were up regulated. However, Tpx was down regulated, and further interpretation of the complementary functions of these antioxidant genes is still required. We also determined the effect of HaGrx, HaGrx3, and HaGrx5 knockdown on antioxidant enzymatic activity and metabolite content. The enzymatic activities of SOD, CAT, and POD, and the metabolite contents of hydrogen peroxide, ascorbate, protein carbonyl, and total GSH increased after RNAi mediated knockdown of HaGrx, HaGrx3, and HaGrx5. These results supported our hypothesis that HaGrx, HaGrx3, and HaGrx5 play important roles in antioxidant defense of Helicoverpa armigera and provided a theoretical basis for further in-depth study of physiological function in the insect glutaredoxin family genes.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.06.007
      Issue No: Vol. 75 (2016)
  • RNAi induced knockdown of a cadherin-like protein (EF531715) does not
           affect toxicity of Cry34/35Ab1 or Cry3Aa to Diabrotica virgifera virgifera
           larvae (Coleoptera: Chrysomelidae)
    • Authors: Sek Yee Tan; Murugesan Rangasamy; Haichuan Wang; Ana María Vélez; James Hasler; David McCaskill; Tao Xu; Hong Chen; Jessica Jurzenski; Matthew Kelker; Xiaoping Xu; Kenneth Narva; Blair D. Siegfried
      Pages: 117 - 124
      Abstract: Publication date: August 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 75
      Author(s): Sek Yee Tan, Murugesan Rangasamy, Haichuan Wang, Ana María Vélez, James Hasler, David McCaskill, Tao Xu, Hong Chen, Jessica Jurzenski, Matthew Kelker, Xiaoping Xu, Kenneth Narva, Blair D. Siegfried
      The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is an important maize pest throughout most of the U.S. Corn Belt. Bacillus thuringiensis (Bt) insecticidal proteins including modified Cry3Aa and Cry34/35Ab1 have been expressed in transgenic maize to protect against WCR feeding damage. To date, there is limited information regarding the WCR midgut target sites for these proteins. In this study, we examined whether a cadherin-like gene from Diabrotica virgifera virgifera (DvvCad; GenBank accession # EF531715) associated with WCR larval midgut tissue is necessary for Cry3Aa or Cry34/35Ab1 toxicity. Experiments were designed to examine the sensitivity of WCR to trypsin activated Cry3Aa and Cry34/35Ab1 after oral feeding of the DvvCad dsRNA to knockdown gene expression. Quantitative real-time PCR confirmed that DvvCad mRNA transcript levels were reduced in larvae treated with cadherin dsRNA. Relative cadherin expression by immunoblot analysis and nano-liquid chromatography - mass spectrometry (nanoLC-MS) of WCR neonate brush border membrane vesicle (BBMV) preparations exposed to DvvCad dsRNA confirmed reduced cadherin expression when compared to BBMV from untreated larvae. However, the larval mortality and growth inhibition of WCR neonates exposed to cadherin dsRNA for two days followed by feeding exposure to either Cry3Aa or Cry34/35Ab1 for four days was not significantly different to that observed in insects exposed to either Cry3Aa or Cry34/35Ab1 alone. In combination, these results suggest that cadherin is unlikely to be involved in the toxicity of Cry3Aa or Cry34/35Ab1 to WCR.
      Graphical abstract image

      PubDate: 2016-08-04T01:24:27Z
      DOI: 10.1016/j.ibmb.2016.06.006
      Issue No: Vol. 75 (2016)
  • Characterization of two coleopteran α-amylases and molecular insights
           into their differential inhibition by synthetic α-amylase inhibitor,
    • Authors: Sonal M. Channale; Amey J. Bhide; Yashpal Yadav; Garima Kashyap; Pankaj K. Pawar; V.L. Maheshwari; Sureshkumar Ramasamy; Ashok P. Giri
      Pages: 1 - 11
      Abstract: Publication date: Available online 27 April 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Sonal M. Channale, Amey J. Bhide, Yashpal Yadav, Garima Kashyap, Pankaj K. Pawar, V.L. Maheshwari, Sureshkumar Ramasamy, Ashok P. Giri
      Post-harvest insect infestation of stored grains makes them unfit for human consumption and leads to severe economic loss. Here, we report functional and structural characterization of two coleopteran α-amylases viz. Callosobruchus chinensis α-amylase (CcAmy) and Tribolium castaneum α-amylase (TcAmy) along with their interactions with proteinaceous and non-proteinaceous α-amylase inhibitors. Secondary structural alignment of CcAmy and TcAmy with other coleopteran α-amylases revealed conserved motifs, active sites, di-sulfide bonds and two point mutations at spatially conserved substrate or inhibitor-binding sites. Homology modeling and molecular docking showed structural differences between these two enzymes. Both the enzymes had similar optimum pH values but differed in their optimum temperature. Overall, pattern of enzyme stabilities were similar under various temperature and pH conditions. Further, CcAmy and TcAmy differed in their substrate affinity and catalytic efficiency towards starch and amylopectin. HPLC analysis detected common amylolytic products like maltose and malto-triose while glucose and malto-tetrose were unique in CcAmy and TcAmy catalyzed reactions respectively. At very low concentrations, wheat α-amylase inhibitor was found to be superior over the acarbose as far as complete inhibition of amylolytic activities of CcAmy and TcAmy was concerned. Mechanism underlying differential amylolytic reaction inhibition by acarbose was discussed.
      Graphical abstract image

      PubDate: 2016-04-28T03:39:47Z
      DOI: 10.1016/j.ibmb.2016.04.009
      Issue No: Vol. 74 (2016)
  • Characterization of a ligand-gated cation channel based on an inositol
           receptor in the silkworm, Bombyx mori
    • Authors: Shingo Kikuta; Haruka Endo; Natsuo Tomita; Tomoyuki Takada; Chiharu Morita; Kiyoshi Asaoka; Ryoichi Sato
      Pages: 12 - 20
      Abstract: Publication date: Available online 27 April 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Shingo Kikuta, Haruka Endo, Natsuo Tomita, Tomoyuki Takada, Chiharu Morita, Kiyoshi Asaoka, Ryoichi Sato
      Insect herbivores recognize non-volatile compounds in plants to direct their feeding behavior. Gustatory receptors (Gr) appear to be required for nutrient recognition by gustatory organs in the mouthparts of insects. Gr10 is expressed in Bombyx mori (BmGr10) mouthparts such as maxillary galea, maxillary palp, and labrum. BmGr10 is predicted to function in sugar recognition; however, the precise biochemical function remains obscure. Larvae of B. mori are monophagous feeders able to find and feed on mulberry leaves. Soluble mulberry leaf extract contains sucrose, glucose, fructose, and myo-inositol. In this study, we identified BmGr10 as an inositol receptor using electrophysiological analysis with the Xenopus oocyte expression system and Ca2+ imaging techniques using mammalian cells. These results demonstrated that Xenopus oocytes or HEK293T cells expressing BmGr10 specifically respond to myo-inositol and epi-inositol but do not respond to any mono-, di-, or tri-saccharides or to some sugar alcohols. These inositols caused Ca2+ and Na+ influxes into the cytoplasm independently of a G protein-mediated signaling cascade, indicating that BmGr10 is a ligand-gated cation channel. Overall, BmGr10 plays an important role in the myo-inositol recognition required for B. mori larval feeding behavior.
      Graphical abstract image

      PubDate: 2016-04-28T03:39:47Z
      DOI: 10.1016/j.ibmb.2016.04.010
      Issue No: Vol. 74 (2016)
  • CRISPR/Cas9 in locusts: Successful establishment of an olfactory
           deficiency line by targeting the mutagenesis of an odorant receptor
           co-receptor (Orco)
    • Authors: Yan Li; Jie Zhang; Dafeng Chen; Pengcheng Yang; Feng Jiang; Xianhui Wang; Le Kang
      Abstract: Publication date: Available online 12 October 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yan Li, Jie Zhang, Dafeng Chen, Pengcheng Yang, Feng Jiang, Xianhui Wang, Le Kang
      Locusts are important agricultural pests worldwide and regarded as study models for entomology. However, the absence of targeted gene manipulation systems for locusts has restricted their applications for research. Herein, we report the successful use of the CRISPR/Cas9 system to induce a targeted heritable mutagenesis of the migratory locust, Locusta migratoria. The target sequence of gRNA was designed to disrupt the gene encoding the odorant receptor co-receptor (Orco) and examine the roles of the odorant receptor pathway in the locust. Microinjection of the mixture of Cas9-mRNA and Orco-gRNA into the locust eggs resulted in efficient target-gene editing at a rate of 71.7% in G0 animals and achieved a germline efficiency of up to 88.1% in G1 animals. By a crossing strategy, we successfully established stable Orco mutant lines. EAGs and SSRs indicated that the fourth-instar nymphs of the Orco mutants showed severely impaired electrophysiological responses to multiple odors. The Orco mutant locusts lost an attraction response to aggregation pheromones under the crowding conditions. The locomotor activity and body coloration of the Orco mutant locusts did not significantly differ from those of the two other genotypes. This study provides an easy and effective approach by using the CRISPR/Cas9 system for generating loss-of-function mutants for functional genetic studies of locusts and for managing insect pests.
      Graphical abstract image

      PubDate: 2016-10-14T11:50:29Z
      DOI: 10.1016/j.ibmb.2016.10.003
  • Proteomic analysis of castor bean tick Ixodes ricinus: A focus on
           chemosensory organs
    • Authors: Immacolata Iovinella; Liping Ban Limei Song Paolo Pelosi Francesca Romana
      Abstract: Publication date: Available online 29 September 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Immacolata Iovinella, Liping Ban, Limei Song, Paolo Pelosi, Francesca Romana Dani
      In arthropods, the large majority of studies on olfaction have been focused on insects, where most of the proteins involved have been identified. In particular, chemosensing in insects relies on two families of membrane receptors, olfactory/gustatory receptors (ORs/GRs) and ionotropic receptors (IRs), and two classes of soluble proteins, odorant-binding proteins (OBPs) and chemosensory proteins (CSPs). In other arthropods, such as ticks and mites, only IRs have been identified, while genes encoding for OBPs and CSPs are absent. A third class of soluble proteins, called Niemann-Pick C2 (NPC2) has been suggested as potential carrier for semiochemicals both in insects and other arthropods. Here we report the results of a proteomic analysis on olfactory organs (Haller's organ and palps) and control tissues of the tick Ixodes ricinus, and of immunostaining experiments targeting NPC2s. Adopting different extraction and proteomic approaches, we identified a large number of proteins, and highlighted those differentially expressed. None of the 13 NPC2s known for this species was found. On the other hand, using immunocytochemistry, we detected reaction against one NPC2 in the Haller's organ and palp sensilla. We hypothesised that the low concentration of such proteins in the tick's tissues could possibly explain the discrepant results. In ligand-binding assays the corresponding recombinant NPC2 showed good affinity to the fluorescent probe N-phenylnaphthylamine and to few organic compounds, supporting a putative role of NPC2s as odorant carriers.
      Graphical abstract image

      PubDate: 2016-10-01T00:48:47Z
  • Gossypol toxicity and detoxification in Helicoverpa armigera and Heliothis
    • Authors: Corinna Krempl; Hanna M. Heidel-Fischer; Guillermo Hugo Jiménez-Alemán; Michael Reichelt; Riya Christina Menezes; Wilhelm Boland; Heiko Vogel; David G. Heckel; Nicole Joußen
      Abstract: Publication date: Available online 26 September 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Corinna Krempl, Hanna M. Heidel-Fischer, Guillermo Hugo Jiménez-Alemán, Michael Reichelt, Riya Christina Menezes, Wilhelm Boland, Heiko Vogel, David G. Heckel, Nicole Joußen
      Gossypol is a polyphenolic secondary metabolite produced by cotton plants, which is toxic to many organisms. Gossypol's aldehyde groups are especially reactive, forming Schiff bases with amino acids of proteins and cross-linking them, inhibiting enzyme activities and contributing to toxicity. Very little is known about gossypol's mode of action and its detoxification in cotton-feeding insects that can tolerate certain concentrations of this compound. Here, we tested the toxicity of gossypol and a gossypol derivative lacking free aldehyde groups (SB-gossypol) toward Helicoverpa armigera and Heliothis virescens, two important pests on cotton plants. Larval feeding studies with these two species on artificial diet supplemented with gossypol or SB-gossypol revealed no detectable toxicity of gossypol, when the aldehyde groups were absent. A cytochrome P450 enzyme, CYP6AE14, is upregulated in H. armigera feeding on gossypol, and has been claimed to directly detoxify gossypol. However, using in vitro assays with heterologously expressed CYP6AE14, no metabolites of gossypol were detected, and further studies suggest that gossypol is not a direct substrate of CYP6AE14. Furthermore, larvae feeding on many other plant toxins also upregulate CYP6AE14. Our data demonstrate that the aldehyde groups are critical for the toxicity of gossypol when ingested by H. armigera and H. virescens larvae, and suggest that CYP6AE14 is not directly involved in gossypol metabolism, but may play a role in the general stress response of H. armigera larvae toward plant toxins.
      Graphical abstract image

      PubDate: 2016-10-01T00:48:47Z
      DOI: 10.1016/j.ibmb.2016.09.003
  • RNA interference in the Colorado potato beetle, Leptinotarsa decemlineata:
           Identification of key contributors
    • Authors: June-Sun Yoon; Jayendra Shukla; Zhong Jun Gong; Kanakachari Mogilicherla; Subba Reddy Palli
      Abstract: Publication date: Available online 26 September 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): June-Sun Yoon, Jayendra Shukla, Zhong Jun Gong, Kanakachari Mogilicherla, Subba Reddy Palli
      RNA interference (RNAi) is a useful reverse genetics tool for investigation of gene function as well as for practical applications in many fields including medicine and agriculture. RNAi works very well in coleopteran insects including the Colorado potato beetle (CPB), Leptinotarsa decemlineata. We used a cell line (Lepd-SL1) developed from CPB to identify genes that play key roles in RNAi. We screened 50 genes with potential functions in RNAi by exposing Lepd-SL1 cells to dsRNA targeting one of the potential RNAi pathway genes followed by incubation with dsRNA targeting inhibitor of apoptosis (IAP, silencing of this gene induces apoptosis). Out of 50 genes tested, silencing of 29 genes showed an effect on RNAi. Silencing of five genes (Argonaute-1, Argonaute-2a, Argonaute-2b, Aubergine and V-ATPase 16 kDa subunit 1, Vha16) blocked RNAi suggesting that these genes are essential for functioning of RNAi in Lepd-SL1 cells. Interestingly, Argonaute-1 and Aubergine are known to function in miRNA and piRNA pathway respectively are also critical to siRNA pathway. Using 32P labeled dsRNA, we showed that these miRNA and piRNA Argonautes but not Argonaute-2 is required for processing of dsRNA to siRNA. Transfection of pIZT/V5 constructs containing these five genes into Sf9 cells (the cells where RNAi does not work well) showed that expression of all genes tested, except the Argonaute-2a, improved RNAi in these cells. Results from Vha16 gene silencing and bafilomycin-A1 treatment suggest that endosomal escape plays an important role in dsRNA-mediated RNAi in Lepd-SL1 cells.
      Graphical abstract image

      PubDate: 2016-10-01T00:48:47Z
      DOI: 10.1016/j.ibmb.2016.09.002
  • Multifaceted biological insights from a draft genome sequence of the
           tobacco hornworm moth, Manduca sexta
    • Authors: Michael Kanost; Estela Arrese Xiaolong Cao Yun-Ru Chen Sanjay Chellapilla
      Abstract: Publication date: Available online 12 August 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Michael R. Kanost, Estela L. Arrese, Xiaolong Cao, Yun-Ru Chen, Sanjay Chellapilla, Marian R. Goldsmith, Ewald Grosse-Wilde, David G. Heckel, Nicolae Herndon, Haobo Jiang, Alexie Papanicolaou, Jiaxin Qu, Jose L. Soulages, Heiko Vogel, James Walters, Robert M. Waterhouse, Seung-Joon Ahn, Francisca C. Almeida, Chunju An, Peshtewani Aqrawi, Anne Bretschneider, William B. Bryant, Sascha Bucks, Hsu Chao, Germain Chevignon, Jayne M. Christen, David F. Clarke, Neal T. Dittmer, Laura C.F. Ferguson, Spyridoula Garavelou, Karl H.J. Gordon, Ramesh T. Gunaratna, Yi Han, Frank Hauser, Yan He, Hanna Heidel-Fischer, Ariana Hirsh, Yingxia Hu, Hongbo Jiang, Divya Kalra, Christian Klinner, Christopher König, Christie Kovar, Ashley R. Kroll, Suyog S. Kuwar, Sandy L. Lee, Rüdiger Lehman, Kai Li, Zhaofei Li, Hanquan Liang, Shanna Lovelace, Zhiqiang Lu, Jennifer H. Mansfield, Kyle J. McCulloch, Tittu Mathew, Brian Morton, Donna M. Muzny, David Neunemann, Fiona Ongeri, Yannick Pauchet, Ling-Ling Pu, Ioannis Pyrousis, Xiang-Jun Rao, Amanda Redding, Charles Roesel, Alejandro Sanchez-Gracia, Sarah Schaack, Aditi Shukla, Guillaume Tetreau, Yang Wang, Guang-Hua Xiong, Walther Traut, Tom K. Walsh, Kim C. Worley, Di Wu, Wenbi Wu, Yuan-Qing Wu, Xiufeng Zhang, Zhen Zou, Hannah Zucker, Adriana D. Briscoe, Thorsten Burmester, Rollie J. Clem, René Feyereisen, Cornelis J.P. Grimmelikhuijzen, Stavros J. Hamodrakas, Bill S. Hansson, Elisabeth Huguet, Lars S. Jermiin, Que Lan, Herman K. Lehman, Marce Lorenzen, Hans Merzendorfer, Ioannis Michalopoulos, David B. Morton, Subbaratnam Muthukrishnan, John G. Oakeshott, Will Palmer, Yoonseong Park, A. Lorena Passarelli, Julio Rozas, Lawrence M. Schwartz, Wendy Smith, Agnes Southgate, Andreas Vilcinskas, Richard Vogt, Ping Wang, John Werren, Xiao-Qiang Yu, Jing-Jiang Zhou, Susan J. Brown, Steven E. Scherer, Stephen Richards, Gary W. Blissard
      Manduca sexta, known as the tobacco hornworm or Carolina sphinx moth, is a lepidopteran insect that is used extensively as a model system for research in insect biochemistry, physiology, neurobiology, development, and immunity. One important benefit of this species as an experimental model is its extremely large size, reaching more than 10 g in the larval stage. M. sexta larvae feed on solanaceous plants and thus must tolerate a substantial challenge from plant allelochemicals, including nicotine. We report the sequence and annotation of the M. sexta genome, and a survey of gene expression in various tissues and developmental stages. The Msex_1.0 genome assembly resulted in a total genome size of 419.4 Mbp. Repetitive sequences accounted for 25.8% of the assembled genome. The official gene set is comprised of 15,451 protein-coding genes, of which 2498 were manually curated. Extensive RNA-seq data from many tissues and developmental stages were used to improve gene models and for insights into gene expression patterns. Genome wide synteny analysis indicated a high level of macrosynteny in the Lepidoptera. Annotation and analyses were carried out for gene families involved in a wide spectrum of biological processes, including apoptosis, vacuole sorting, growth and development, structures of exoskeleton, egg shells, and muscle, vision, chemosensation, ion channels, signal transduction, neuropeptide signaling, neurotransmitter synthesis and transport, nicotine tolerance, lipid metabolism, and immunity. This genome sequence, annotation, and analysis provide an important new resource from a well-studied model insect species and will facilitate further biochemical and mechanistic experimental studies of many biological systems in insects.
      Graphical abstract image

      PubDate: 2016-08-13T02:01:30Z
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
Home (Search)
Subjects A-Z
Publishers A-Z
Your IP address:
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2016