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  Subjects -> BIOLOGY (Total: 2940 journals)
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BIOCHEMISTRY (222 journals)                  1 2     

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AAPS PharmSciTech     Hybrid Journal   (Followers: 4)
Acetic Acid Bacteria     Open Access   (Followers: 1)
ACS Central Science     Hybrid Journal   (Followers: 3)
ACS Chemical Biology     Full-text available via subscription   (Followers: 149)
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: 8)
Advances in Biological Chemistry     Open Access   (Followers: 6)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 8)
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: 13)
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: 6)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 68)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 12)
American Journal of Polymer Science     Open Access   (Followers: 20)
Amino Acids     Hybrid Journal   (Followers: 8)
Analytical Biochemistry     Hybrid Journal   (Followers: 143)
Annals of Clinical Biochemistry     Hybrid Journal   (Followers: 8)
Annual Review of Biochemistry     Full-text available via subscription   (Followers: 49)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 8)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 43)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 15)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 5)
Archives of Biochemistry and Biophysics     Hybrid Journal   (Followers: 22)
Archives of Insect Biochemistry and Physiology     Hybrid Journal   (Followers: 1)
Archives Of Physiology And Biochemistry     Hybrid Journal   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Asian Journal of Biomedical and Pharmaceutical Sciences     Open Access   (Followers: 2)
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: 12)
Biochemical Genetics     Hybrid Journal   (Followers: 3)
Biochemical Journal     Full-text available via subscription   (Followers: 26)
Biochemical Pharmacology     Hybrid Journal   (Followers: 8)
Biochemical Society Transactions     Full-text available via subscription   (Followers: 3)
Biochemical Systematics and Ecology     Hybrid Journal   (Followers: 3)
Biochemistry     Full-text available via subscription   (Followers: 206)
Biochemistry & Pharmacology : Open Access     Open Access   (Followers: 2)
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: 4)
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids     Hybrid Journal   (Followers: 8)
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: 10)
BioInorganic Reaction Mechanisms     Hybrid Journal   (Followers: 1)
Biokemistri     Open Access  
Biological Chemistry     Partially Free   (Followers: 27)
Biomaterials Research     Open Access   (Followers: 2)
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: 45)
Bit├ícora Digital     Open Access  
BMC Biochemistry     Open Access   (Followers: 13)
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)
ChemBioChem     Hybrid Journal   (Followers: 6)
Chemical and Biological Technologies for Agriculture     Open Access  
Chemical Biology & Drug Design     Hybrid Journal   (Followers: 22)
Chemical Engineering Journal     Hybrid Journal   (Followers: 21)
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: 30)
Chemistry and Ecology     Hybrid Journal  
ChemTexts     Hybrid Journal  
Clinica Chimica Acta     Hybrid Journal   (Followers: 33)
Clinical Biochemist Reviews     Full-text available via subscription   (Followers: 1)
Clinical Biochemistry     Hybrid Journal   (Followers: 20)
Clinical Chemistry and Laboratory Medicine     Hybrid Journal   (Followers: 61)
Clinical Lipidology     Full-text available via subscription  
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology     Hybrid Journal   (Followers: 4)
Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 1)
Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology     Hybrid Journal   (Followers: 7)
Comparative Biochemistry and Physiology Part D: Genomics and Proteomics     Hybrid Journal   (Followers: 2)
Comprehensive Biochemistry     Full-text available via subscription   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 10)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 4)
Current Chemical Biology     Hybrid Journal   (Followers: 2)
Current Opinion in Chemical Biology     Hybrid Journal   (Followers: 21)
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: 8)
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: 6)
International Journal of Biochemistry and Biophysics     Open Access  
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: 41)
Journal of Biological Chemistry     Full-text available via subscription   (Followers: 173)
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: 3)
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: 3)
Journal of Investigational Biochemistry     Open Access   (Followers: 2)
Journal of Medical and Biomedical Sciences     Open Access  
Journal of Medical Biochemistry     Open Access   (Followers: 5)
Journal of Medicine and Biomedical Research     Open Access   (Followers: 1)
Journal of Molecular Biochemistry     Open Access   (Followers: 2)
Journal of Neurochemistry     Hybrid Journal   (Followers: 2)
Journal of Nutritional Biochemistry     Hybrid Journal   (Followers: 6)
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: 6)
La Rivista Italiana della Medicina di Laboratorio - Italian Journal of Laboratory Medicine     Hybrid Journal  
Marine Chemistry     Hybrid Journal   (Followers: 6)
Methods in Enzymology     Full-text available via subscription   (Followers: 12)
Molecular and Biochemical Parasitology     Hybrid Journal   (Followers: 2)
Molecular and Cellular Biochemistry     Hybrid Journal   (Followers: 3)
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: 65)
Nature Communications     Open Access   (Followers: 98)
Novelty in Biomedicine     Open Access  
Ocean Acidification     Open Access   (Followers: 1)
Organic & Biomolecular Chemistry     Full-text available via subscription   (Followers: 79)
Parasitology Open     Open Access  
Peptidomics     Open Access  
Pesticide Biochemistry and Physiology     Hybrid Journal   (Followers: 4)
Pharmaceutical Bioprocessing     Full-text available via subscription   (Followers: 1)
Pharmacognosy Magazine     Open Access   (Followers: 2)
Pharmacognosy Research     Open Access   (Followers: 3)
Pharmacognosy Reviews     Open Access   (Followers: 1)
Phytochemistry Reviews     Hybrid Journal  
Plant Physiology and Biochemistry     Hybrid Journal   (Followers: 7)
Plasma Chemistry and Plasma Processing     Hybrid Journal   (Followers: 2)
Polymer Journal     Hybrid Journal   (Followers: 1)
Preparative Biochemistry and Biotechnology     Hybrid Journal   (Followers: 4)

        1 2     

Journal Cover Insect Biochemistry and Molecular Biology
  [SJR: 1.703]   [H-I: 75]   [3 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0965-1748
   Published by Elsevier Homepage  [2970 journals]
  • CRISPR/Cas9 mediated knockout of the abdominal-A homeotic gene in the
           global pest, diamondback moth (Plutella xylostella)
    • 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
       
  • Reduced abundance of the CYP6CY3- targeting let-7 and miR-100 miRNAs
           accounts for host adaptation of Myzus persicae nicotianae
    • 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
       
  • Agonist-mediated activation of Bombyx mori diapause hormone receptor
           signals to extracellular signal-regulated kinases 1 and 2 through
           Gq-PLC-PKC-dependent cascade
    • 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
       
  • A single amino-acid substitution toggles chloride dependence of the
           alpha-amylase paralog amyrel in Drosophila melanogaster and virilis
           species
    • 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
       
  • 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
    • 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
       
  • Editorial Board
    • Abstract: Publication date: July 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 74




      PubDate: 2016-06-05T03:18:59Z
       
  • Role of Bmznf-2, a Bombyx mori CCCH zinc finger gene, in masculinisation
           and differential splicing of Bmtra-2
    • 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
       
  • Editorial Board
    • Abstract: Publication date: June 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 73




      PubDate: 2016-06-05T03:18:59Z
       
  • Functional characterization of SlitPBP3 in Spodoptera litura by
           CRISPR/Cas9 mediated genome editing
    • 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
       
  • Distribution of cuticular proteins in different structures of adult
           Anopheles gambiae
    • 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.
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      PubDate: 2016-05-16T02:14:48Z
       
  • Juvenile hormone facilitates the antagonism between adult reproduction and
           diapause through the methoprene-tolerant gene in the female Colaphellus
           bowringi
    • Abstract: Publication date: Available online 12 May 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Wen Liu, Yi Li, Li Zhu, Fen Zhu, Chao-Liang Lei, Xiao-Ping Wang
      In insects, the process whereby juvenile hormone (JH) regulates short-day (SD)-induced reproductive diapause has been previously investigated. However, we still do not understand the mechanism by which JH regulates long-day (LD)-induced reproductive diapause. In this study, we use a cabbage beetle, Colaphellus bowringi, which is a serious pest of cruciferous vegetables in Asia capable of entering reproductive diapause under LD conditions, as a model to test whether JH regulates female reproductive diapause similar to the mechanism of SD-induced diapause. Our results showed that the JH analog (JHA) methoprene significantly induced ovarian development but inhibited lipid accumulation of diapause-destined adults. Meanwhile, the transcripts of the vitellogenin (Vg) genes were upregulated, whereas the expression of the fat synthesis and stress tolerance genes were downregulated. RNA interference of the JH candidate receptor gene methoprene-tolerant (Met) blocked JH-induced ovarian development and Vg transcription, suggesting a positive regulatory function for JH-Met signaling in reproduction. Furthermore, under reproduction-inducing conditions, Met depletion promoted a diapause-like phenotype, including arrested ovarian development and increased lipid storage, and stimulated the expression of diapause-related genes involved in lipid synthesis and stress tolerance, suggesting JH-Met signaling plays an important role in the inhibition of diapause. Accordingly, our data indicate that JH acts through Met to facilitate development of the reproductive system by upregulating Vg expression while inhibiting diapause by suppressing lipid synthesis and stress tolerance in the cabbage beetle. Combined with previous studies in SD-induced reproductive diapause, we conclude that JH may regulate female reproductive diapause using a conserved Met-dependent pathway, regardless of the length of the photoperiod inducing diapause in insects.
      Graphical abstract image

      PubDate: 2016-05-16T02:14:48Z
       
  • Ecdysteroid signalling components in metamorphosis and development of the
           desert locust, Schistocerca gregaria
    • 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.
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      PubDate: 2016-05-16T02:14:48Z
       
  • Structure, evolution, and expression of antimicrobial silk proteins,
           seroins in Lepidoptera
    • 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.
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      PubDate: 2016-05-16T02:14:48Z
       
  • Functional and immunohistochemical characterization of CCEae3a, a
           carboxylesterase associated with temephos resistance in the major
           arbovirus vectors Aedes aegypti and Ae. albopictus
    • Abstract: Publication date: Available online 13 May 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Linda Grigoraki, Vassileia Balabanidou, Christos Meristoudis, Antonis Miridakis, Hilary Ranson, Luc Swevers, John Vontas
      Temephos is a major organophosphate (OP) larvicide that has been used extensively for the control of Aedes albopictus and Aedes aegypti, the major vectors for viral diseases, such as dengue fever, zika and chikungunya. Resistance to temephos has been recently detected and associated with the upregulation of carboxylesterases (CCEs) through gene amplification, in both species. Here, we expressed the CCEae3a genes which showed the most striking up-regulation in resistant Aedes strains, using the baculovirus system. All CCEae3a variants encoded functional enzymes, with high activity and preference for p-nitrophenyl butyrate, a substrate that was shown capable to differentiate temephos resistant from susceptible Aedes larvae. Enzyme kinetic studies showed that CCEae3as from both Ae. aegypti and Ae. albopictus (CCEae3a_aeg and CCEae3a_alb, respectively) strongly interact with temephos oxon and slowly released the OP molecule, indicating a sequestration resistance mechanism. No difference was detected between resistant and susceptible CCEae3a_aeg variants (CCEae3a_aegR and CCEae3a_aegS, respectively), indicating that previously reported polymorphism is unlikely to play a role in temephos resistance. HPLC/MS showed that CCEae3as were able to metabolize temephos oxon to the temephos monoester [(4-hydroxyphenyl) sulfanyl] phenyl O,O-dimethylphosphorothioate. Western blot and immunolocalization studies, based on a specific antibody raised against the CCEae3a_alb showed that the enzyme is expressed at higher levels in resistant insects, primarily in malpighian tubules (MT) and nerve tissues.
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      PubDate: 2016-05-16T02:14:48Z
       
  • Sequence variation determining stereochemistry of a Δ11 desaturase
           active in moth sex pheromone biosynthesis
    • Abstract: Publication date: Available online 6 May 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Bao-Jian Ding, Colm Carraher, Christer Löfstedt
      A Δ11 desaturase from the oblique banded leaf roller moth Choristoneura rosaceana takes the saturated myristic acid and produces a mixture of (E)-11-tetradecenoate and (Z)-11-tetradecenoate with an excess of the Z isomer (35:65). A desaturase from the spotted fireworm moth Choristoneura parallela also operates on myristic acid substrate but produces almost pure (E)-11-tetradecenoate. The two desaturases share 92% amino acid identity and 97% amino acid similarity. There are 24 amino acids differing between these two desaturases. We constructed mutations at all of these positions to pinpoint the sites that determine the product stereochemistry. We demonstrated with a yeast functional assay that one amino acid at the cytosolic carboxyl terminus of the protein (258E) is critical for the Z activity of the C. rosaceana desaturase. Mutating the glutamic acid (E) into aspartic acid (D) transforms the C. rosaceana enzyme into a desaturase with C. parallela-like activity, whereas the reciprocal mutation of the C. parallela desaturase transformed it into an enzyme producing an intermediate 64:36 E/Z product ratio. We discuss the causal link between this amino acid change and the stereochemical properties of the desaturase and the role of desaturase mutations in pheromone evolution.
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      PubDate: 2016-05-07T04:14:50Z
       
  • Serine protease P-IIc is responsible for the digestion of yolk proteins at
           the late stage of silkworm embryogenesis
    • Abstract: Publication date: Available online 29 April 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Dandan Wang, Yan Zhang, Zhaoming Dong, Pengchao Guo, Sanyuan Ma, Kaiyu Guo, Qingyou Xia, Ping Zhao
      In silkworms, yolk proteins comprise vitellin, egg-specific protein and 30K proteins, which are sequentially degraded by endogenous proteases strictly regulated during embryogenesis. Although the process has been extensively investigated, there is still a gap in the knowledge about the degradation of silkworm yolk proteins on the last two days of embryonic development. In the present study, we isolated and purified a gut serine protease P-IIc, which demonstrated optimal activity at 25 °C and pH 11. Semi-quantitative RT-PCR combined with western blotting showed that P-IIc was actively expressed and significantly accumulated in the gut on the last two days of embryogenesis. When natural yolk proteins were incubated with P-IIc in vitro, vitellin and ESP were selectively degraded. P-IIc also demonstrated activity towards 30K proteins as evidenced by rapid and complete digestion of BmLP1 and partial digestion of BmLP2 and BmLP3. Furthermore, RNAi knockdown of P-IIc in silkworm embryos significantly reduced the degradation rate of residual yolk proteins on embryonic day 10. Taken together, our results indicate that P-IIc represents an embryonic gut protease with a relatively broad substrate specificity, which plays an important role in the degradation of yolk proteins at the late stage of silkworm embryogenesis.
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      PubDate: 2016-05-02T03:58:18Z
       
  • JNK signaling mediates wing form polymorphism in brown planthoppers
           (Nilaparvata lugens)
    • Abstract: Publication date: Available online 24 April 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Xinda Lin, Yili Xu, Yun Yao, Bo Wang, Mark D. Lavine, Laura Corley Lavine
      Wing polyphenism is considered to be an adaptive trade-off between migration (long winged forms) and reproduction (short winged forms), determined by various environmental conditions. The c-Jun NH2-terminal kinase (JNK) is crucial for the regulation of the activity of a number of transcription factors, and is activated under stress and environmental fluctuations where it functions in maintaining cell viability and proliferation. We used RNA interference and a pharmacological inhibitor of JNK to test the role of JNK signaling in regulating the wing dimorphism of the brown planthopper, Nilaparvata lugens. Silencing NlJNK increased the proportion of short winged female adults, reminiscent of the effect of silencing inhibitory components of the insulin-signaling pathway, such as NlAkt. However, silencing of the JNK-activated transcription factors NlJun and NlFos did not change the wing form ratio significantly, indicating that NlJNK may not act through NlJun and NlFos in mediating this process. In summary, JNK signaling may play a role in determining wing polymorphism in N. lugens, at least in females.
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      PubDate: 2016-04-28T03:39:47Z
       
  • Gene expression changes in the tyrosine metabolic pathway regulate
           caste-specific cuticular pigmentation of termites
    • Abstract: Publication date: Available online 26 April 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Yudai Masuoka, Kiyoto Maekawa
      In social insects, all castes have characteristic phenotypes suitable for their own tasks and to engage in social behavior. The acquisition of caste-specific phenotypes was a key event in the course of social insect evolution. However, understanding of the genetic basis and the developmental mechanisms that produce these phenotypes is still very limited. In particular, termites normally possess more than two castes with specific phenotypes (i.e. workers, soldiers, and reproductives), but proximate developmental mechanisms are far from being fully understood. In this study, we focused on the pigmentation of the cuticle as a model trait for caste-specific phenotypes, during the molts of each caste; workers, soldiers, presoldiers (intermediate stage of soldiers), and alates (primary reproductives) in Zootermopsis nevadensis. Expression patterns of cuticular tanning genes (members of the tyrosine metabolic pathway) were different among each molt, and high expression levels of several “key genes” were observed during each caste differentiation. For the differentiation of castes with well-tanned cuticles (i.e. soldiers and alates), all focal genes except DDC in the former were highly expressed. On the other hand, high expression levels of yellow and aaNAT were observed during worker and presoldier molts, respectively, but most other genes in the pathway were expressed at low levels. RNA interference (RNAi) of these key genes affected caste-specific cuticular pigmentation, leading to soldiers with yellowish-white heads and pigmented mandibular tips, presoldiers with partly pigmented head cuticles, and alates with the yellow head capsules. These results suggest that the pigmentation of caste-specific cuticles is achieved by the regulation of gene expression in the tyrosine metabolic pathway.
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      PubDate: 2016-04-28T03:39:47Z
       
  • Mode of action of triflumezopyrim: A novel mesoionic insecticide which
           inhibits the nicotinic acetylcholine receptor
    • Abstract: Publication date: Available online 26 April 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Daniel Cordova, Eric A. Benner, Mark E. Schroeder, Caleb W. Holyoke, Wenming Zhang, Thomas F. Pahutski, Robert M. Leighty, Daniel R. Vincent, Jason C. Hamm
      Triflumezopyrim, a newly commercialized molecule from DuPont Crop Protection, belongs to the novel class of mesoionic insecticides. This study characterizes the biochemical and physiological action of this novel insecticide. Using membranes from the aphid, Myzus persicae, triflumezopyrim was found to displace [3H]-imidacloprid with a Ki value of 43 nM with competitive binding results indicating that triflumezopyrim binds to the orthosteric site of the nicotinic acetylcholine receptor (nAChR). In voltage clamp studies using dissociated Periplaneta americana neurons, triflumezopyrim inhibits nAChR currents with an IC50 of 0.6 nM. Activation of nAChR currents was minimal and required concentrations ≥100 μM. Xenopus oocytes expressing chimeric nAChRs (Drosophila α2/chick β2) showed similar inhibitory effects from triflumezopyrim. In P. americana neurons, co-application experiments with acetylcholine reveal the inhibitory action of triflumezopyrim to be rapid and prolonged in nature. Such physiological action is distinct from other insecticides in IRAC Group 4 in which the toxicological mode of action is attributed to nAChR agonism. Mesoionic insecticides act via inhibition of the orthosteric binding site of the nAChR despite previous beliefs that such action would translate to poor insect control. Triflumezopyrim is the first commercialized insecticide from this class and provides outstanding control of hoppers, including the brown planthopper, Nilaparvata lugens, which has developed strong resistance to neonicotinoids such as imidacloprid.
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      PubDate: 2016-04-28T03:39:47Z
       
  • Characterization of two coleopteran α-amylases and molecular insights
           into their differential inhibition by synthetic α-amylase inhibitor,
           acarbose
    • 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.
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      PubDate: 2016-04-28T03:39:47Z
       
  • Characterization of a ligand-gated cation channel based on an inositol
           receptor in the silkworm, Bombyx mori
    • 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.
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      PubDate: 2016-04-28T03:39:47Z
       
  • Discrimination of cis-trans sex pheromone components in two sympatric
           Lepidopteran species
    • Abstract: Publication date: Available online 21 April 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Sufang Zhang, Xiangbo Kong, Sangzi Ze, Hongbin Wang, Aizhu Lin, Fu Liu, Zhen Zhang
      Pheromone-binding proteins (PBPs) play an important role in the recognition of pheromones by insects. However, the abilities of these PBPs to discriminate pheromone components and recognize the isomers are unclear. Dendrolimus houi and Dendrolimus kikuchii are two sympatric coniferous pests whose pheromones have cis-trans isomers. We used these insect species to detect the precise recognition abilities of PBPs. The four PBPs examined showed male-biased antenna-intensive expression patterns, whereas PBP1 showed higher expression than PBP2 in the antenna. DhouPBP1 only bound to a minor interspecific pheromone component, whereas DhouPBP2 bound to all three intraspecific components and another minor interspecific component. DkikPBP1 and DkikPBP2 could recognize all three intraspecific components with affinities negatively correlated with their ratios, and they bound to interspecific pheromones with affinity that was positively correlated with the ratios. The four PBPs have different cis-trans isomer discrimination abilities, i.e., DhouPBP1 and DkikPBP1 could not discriminate the two cis-trans isomer pairs of pheromones from the two species, whereas DhouPBP2 could discriminate between both pairs, and DkikPBP2 could only discriminate one pair. Overall, PBPs from D. houi and D. kikuchii use different mechanisms to help the moths to discriminate the intra- and interspecific pheromone components. Our work will contribute to better understanding of the sex pheromone recognition mechanism in these two sister species of moths and provide insights into more effective management practices of these pest species.
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      PubDate: 2016-04-24T02:53:00Z
       
  • A CRISPR/Cas9 mediated point mutation in the alpha 6 subunit of the
           nicotinic acetylcholine receptor confers resistance to spinosad in
           Drosophila melanogaster
    • Abstract: Publication date: Available online 24 April 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Christoph T. Zimmer, William T. Garrood, A. Mirel Puinean, Manuela Eckel-Zimmer, Martin S. Williamson, T.G. Emyr Davies, Chris Bass
      Spinosad, a widely used and economically important insecticide, targets the nicotinic acetylcholine receptor (nAChRs) of the insect nervous system. Several studies have associated loss of function mutations in the insect nAChR α6 subunit with resistance to spinosad, and in the process identified this particular subunit as the specifc target site. More recently a single non-synoymous point mutation, that does not result in loss of function, was identified in spinosad resistant strains of three insect species that results in an amino acid substitution (G275E) of the nAChR α6 subunit. The causal role of this mutation has been called into question as, to date, functional evidence proving its involvement in resistance has been limited to the study of vertebrate receptors. Here we use the CRISPR/Cas9 gene editing platform to introduce the G275E mutation into the nAChR α6 subunit of Drosophila melanogaster. Reverse transcriptase-PCR and sequencing confirmed the presence of the mutation in Dα6 transcripts of mutant flies and verified that it does not disrupt the normal splicing of the two exons in close vicinity to the mutation site. A marked decrease in sensitivity to spinosad (66-fold) was observed in flies with the mutation compared to flies of the same genetic background minus the mutation, clearly demonstrating the functional role of this amino acid substitution in resistance to spinosad. Although the resistance levels observed are 4.7-fold lower than exhibited by a fly strain with a null mutation of Dα6, they are nevertheless predicited to be sufficient to result in resistance to spinosad at recommended field rates. Reciprocal crossings with susceptible fly strains followed by spinosad bioassays revealed G275E is inherited as an incompletley recessive trait, thus resembling the mode of inheritance described for this mutation in the western flower thrips, Frankliniella occidentalis. This study both resolves a debate on the functional significance of a target-site mutation and provides an example of how recent advances in genome editing can be harnessed to study insecticide resistance.
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      PubDate: 2016-04-24T02:53:00Z
       
  • Serpin-5 regulates prophenoloxidase activation and antimicrobial peptide
           pathways in the silkworm, Bombyx mori
    • Abstract: Publication date: June 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 73
      Author(s): Junlan Li, Li Ma, Zhe Lin, Zhen Zou, Zhiqiang Lu
      The prophenoloxidase (PPO) activation pathway and Toll pathway are two critical insect immune responses against microbial infection. Activation of these pathways is mediated by an extracellular serine protease cascade, which is negatively regulated by serpins. In this study, we found that the mRNA abundance of silkworm serpin-5 (BmSpn-5) increased dramatically in the fat body after bacterial infection. The expression level of antimicrobial peptides (AMPs), gloverin-3, cecropin-D and -E decreased in the silkworm larvae injected with recombinant BmSpn-5 protein. Meanwhile, the inhibition of beads melanization, systemic melanization and PPO activation by BmSpn-5 was also observed. By means of immunoaffinity purification and analysis by mass spectrometry, we identified that the silkworm clip domain serine proteases BmHP6 and BmSP21 form a complex with BmSpn-5, which suggests that BmHP6 and SP21 are the cognate proteases of BmSpn-5 and are essential in the serine protease cascade that activates the Toll and PPO pathways. Our study provides a comprehensive characterization of BmSpn-5 and sheds light on the multiple pathways leading to PPO activation and their regulation by serpins.
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      PubDate: 2016-04-20T02:30:05Z
       
  • Editorial Board
    • Abstract: Publication date: May 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 72




      PubDate: 2016-04-20T02:30:05Z
       
  • Mitochondrial structure and dynamics as critical factors in honey bee
           (Apis mellifera L.) caste development
    • Abstract: Publication date: Available online 4 April 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Douglas Elias Santos, Luciane Carla Alberici, Klaus Hartfelder
      The relationship between nutrition and phenotype is an especially challenging question in cases of facultative polyphenism, like the castes of social insects. In the honey bee, Apis mellifera, unexpected modifications in conserved signaling pathways revealed the hypoxia response as a possible mechanism underlying the regulation of body size and organ growth. Hence, the current study was designed to investigate possible causes of why the three hypoxia core genes are overexpressed in worker larvae. Parting from the hypothesis that this has an endogenous cause and is not due to differences in external oxygen levels we investigated mitochondrial numbers and distribution, as well as mitochondrial oxygen consumption rates in fat body cells of queen and worker larvae during the caste fate-critical larval stages. By immunofluorescence and electron microscopy we found higher densities of mitochondria in queen larval fat body, a finding further confirmed by a citrate synthase assay quantifying mitochondrial functional units. Oxygen consumption measurements by high-resolution respirometry revealed that queen larvae have higher maximum capacities of ATP production at lower physiological demand. Finally, the expression analysis of mitogenesis-related factors showed that the honey bee TFB1 and TFB2 homologs, and a nutritional regulator, ERR, are overexpressed in queen larvae. These results are strong evidence that the differential nutrition of queen and worker larvae by nurse bees affects mitochondrial dynamics and functionality in the fat body of these larvae, hence explaining their differential hypoxia response.
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      PubDate: 2016-04-08T01:42:34Z
       
  • Functional validation of the carbon dioxide receptor in labial palps of
           Helicoverpa armigera moths
    • Abstract: Publication date: Available online 7 April 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Chao Ning, Ke Yang, Meng Xu, Ling-Qiao Huang, Chen-Zhu Wang
      Adult moths possess an organ in their labial palps, the labial-palp pit organ, which is specialized for sensing carbon dioxide (CO2). They use CO2 as a cue to detect healthy plants and find food or lay eggs on them. The molecular bases of the CO2 receptor in Drosophila melanogaster and Aedes aegypti have been reported, but the molecular mechanisms of the CO2 receptor in Lepidoptera remains elusive. In this study, we first re-examined three putative Helicoverpa armigera CO2 gustatory receptor genes (HarmGr1, HarmGr2, and HarmGr3), and then analyzed expression patterns of them. RT-PCR results verified they were predominantly expressed in the labial palps of H. armigera. Thus, we used in situ hybridization to localize the expression of three genes in the labial palps. We found that all three genes were co-expressed in the same cells of the labial palps. Next, we employed the Xenopus laevis oocyte expression system and the two-electrode voltage-clamp recording to study the function of the three genes. Results showed that only oocytes co-expressing HarmGr1 and HarmGr3 or co-expressing HarmGr1, HarmGr2 and HarmGr3 gave robust responses to NaHCO3. Finally, we confirmed that the sensory cells in labial palps of both females and males show dose dependent responses to CO2 stimuli by using single sensillum recording. Our work uncovers that HarmGr1 and HarmGr3 are indispensable and sufficient for CO2 sensing in labial palps of H. armigera.
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      PubDate: 2016-04-08T01:42:34Z
       
  • Molybdenum cofactor deficiency causes translucent integument, male-biased
           lethality, and flaccid paralysis in the silkworm Bombyx mori
    • Abstract: Publication date: Available online 1 April 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Tsuguru Fujii, Kimiko Yamamoto, Yutaka Banno
      Uric acid accumulates in the epidermis of Bombyx mori larvae and renders the larval integument opaque and white. Yamamoto translucent (oya) is a novel spontaneous mutant with a translucent larval integument and unique phenotypic characteristics, such as male-biased lethality and flaccid larval paralysis. Xanthine dehydrogenase (XDH) that requires a molybdenum cofactor (MoCo) for its activity is a key enzyme for uric acid synthesis. It has been observed that injection of a bovine xanthine oxidase, which corresponds functionally to XDH and contains its own MoCo activity, changes the integuments of oya mutants from translucent to opaque and white. This finding suggests that XDH/MoCo activity might be defective in oya mutants. Our linkage analysis identified an association between the oya locus and chromosome 23. Because XDH is not linked to chromosome 23 in B. mori, MoCo appears to be defective in oya mutants. In eukaryotes, MoCo is synthesized by a conserved biosynthesis pathway governed by four loci (MOCS1, MOCS2, MOCS3, and GEPH). Through a candidate gene approach followed by sequence analysis, a 6-bp deletion was detected in an exon of the Bombyx mori molybdenum cofactor synthesis-step 1 gene (BmMOCS1) in the oya strain. Moreover, recombination was not observed between the oya and BmMOCS1 loci. These results indicate that the BmMOCS1 locus is responsible for the oya locus. Finally, we discuss the potential cause of male-biased lethality and flaccid paralysis observed in the oya mutants.
      Graphical abstract image

      PubDate: 2016-04-04T01:34:08Z
       
  • Hyaluronidase activity in the salivary glands of tabanid flies
    • Abstract: Publication date: Available online 2 April 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Vera Volfova, Viktorie Tothova, Petr Volf
      Tabanids are haematophagous insects that act as biological and mechanical vectors of various diseases, including viruses, bacteria and parasites. The saliva of these insects contains strong anticoagulant and vasodilatory activities as well as immunoregulatory peptides. Here we demonstrate pronounced hyaluronidase (hyase) activity in ten tabanid species of the genera Chrysops, Haematopota, Hybomitra and Tabanus. Compared to other haematophagous insects, the ability of tabanid hyases to hydrolyze hyaluronic acid (HA) is extremely high, for example the enzyme activity of Hybomitra muehlfeldi was found to be 32-fold higher than the salivary hyase activity of the sand fly Phlebotomus papatasi. Hyases of all ten tabanid species tested also cleaved chondroitin sulfate A, another glycosaminoglycan present in the extracellular matrix of vertebrates. The pH optimum of the enzyme activity was measured in eight tabanid species; the hyase of Haemopota pluvialis was the only one with optimum at pH 4.0, while in the other seven species the activity optimum was at 5.0. SDS PAGE zymography showed the monomeric character of the enzymes in all tabanid species tested. Under non-reducing conditions the activities were visible as single bands with estimated MW between 35 and 52 kDa. The very high hyaluronidase activity in tabanid saliva might be related to their aggressive biting behavior as well as to their high efficiency as mechanical vectors. As they are supposedly involved in the enlargement of feeding hematomas, hyases might contribute to the mechanical transmission of pathogens. Pathogens present in vector mouthparts are co-inoculated into the vertebrate host together with saliva and may benefit from increased tissue permeability and the immunomodulatory activity of the salivary hyase.
      Graphical abstract image

      PubDate: 2016-04-04T01:34:08Z
       
  • Editorial Board
    • Abstract: Publication date: April 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 71




      PubDate: 2016-03-26T01:05:00Z
       
  • Expansion of CRISPR Targeting Sites in Bombyx mori
    • Abstract: Publication date: Available online 24 March 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Baosheng Zeng, Shuai Zhan, Yueqiang Wang, Yuping Huang, Jun Xu, Qun Liu, Zhiqian Li, Yongping Huang, Anjiang Tan
      The CRISPR/Cas9 system has been proven as a revolutionary genome engineering tool. In most cases, single guide RNA (sgRNA) targeting sites have been designed as GN19NGG or GGN18NGG, because of restriction of the initiation nucleotide for RNA Pol III promoters. Here, we demonstrate that the U6 promoter from a lepidopteran model insect, Bombyx mori, effectively expressed the sgRNA initiated with any nucleotide bases (adenine, thymine, guanine or cytosine), which further expands the CRISPR targeting space. A detailed expansion index in the genome was analysed when N20NGG was set as the CRISPR targeting site instead of GN19NGG, and revealed a significant increase of suitable targets, with the highest increase occurring on the Z sex chromosome. Transfection of different types of N20NGG sgRNAs targeting the enhanced green fluorescent protein (EGFP) combined with Cas9, significantly reduced EGFP expression in the BmN cells. An endogenous gene, BmBLOS2, was also disrupted by using various types of N20NGG sgRNAs, and the cleavage efficiency of N20NGG sgRNAs with different initial nucleotides and GC contents was evaluated in vitro. Furthermore, transgenic silkworms expressing Cas9 and sgRNAs targeting the BmBLOS2 gene were generated with many types of mutagenesis. The typical transparent skin phenotype in knock-out silkworms was stable and inheritable, suggesting that N20NGG sgRNAs function sufficiently in vivo. Our findings represent a renewal of CRISPR/Cas9 target design and will greatly facilitate insect functional genetics research.
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      PubDate: 2016-03-26T01:05:00Z
       
  • Knockdown of Drosophila hemoglobin suggests a role in O2 homeostasis
    • Abstract: Publication date: Available online 18 March 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Eva Gleixner, Fabian Ripp, Thomas Gorr, Reinhard Schuh, Christian Wolf, Thorsten Burmester, Thomas Hankeln
      Almost all insects are equipped with a tracheal system, which appears to be sufficient for O2 supply even in phases of high metabolic activity. Therefore, with the exception of a few species dwelling in hypoxic habitats, specialized respiratory proteins had been considered unnecessary in insects. The recent discovery and apparently universal presence of intracellular hemoglobins in insects has remained functionally unexplained. The fruitfly Drosophila melanogaster harbors three different globin genes (referred to as glob1-3). Glob1 is the most highly expressed globin and essentially occurs in the tracheal system and the fat body. To better understand the functions of insect globins, the levels of glob1 were modulated in Drosophila larvae and adults by RNAi-mediated knockdown and transgenic over-expression. No effects on the development were observed in flies with manipulated glob1 levels. However, the knockdown of glob1 led to a significantly reduced survival rate of adult flies under hypoxia (5% and 1.5% O2). Surprisingly, the glob1 knockdown flies also displayed increased resistance towards the reactive oxygen species-forming agent paraquat, which may be explained by a restricted availability of O2 resulting in decreased formation of harmful O2 -. In summary, our results suggest an important functional role of glob1 in O2 homeostasis, possibly by enhancing O2 supply.
      Graphical abstract image

      PubDate: 2016-03-22T09:36:08Z
       
  • The ACBP gene family in Rhodnius prolixus: Expression, characterization
           and function of RpACBP-1
    • Abstract: Publication date: Available online 19 March 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): David Majerowicz, Hans K. Hannibal-Bach, Rodolfo S.C. Castro, Bruno L. Bozaquel-Morais, Michele Alves-Bezerra, Luciano A.M. Grillo, Claudio A. Masuda, Nils J. Færgeman, Jens Knudsen, Katia C. Gondim
      The acyl-CoA-binding proteins (ACBP) constitute a family of conserved proteins that bind acyl-CoA with high affinity and protect it from hydrolysis. Thus, ACBPs may have essential roles in basal cellular lipid metabolism. The genome of the insect Rhodnius prolixus encodes five ACBP genes similar to those described for other insect species. The qPCR analysis revealed that these genes have characteristic expression profiles in insect organs, suggesting that they have specific roles in insect physiology. Recombinant RpACBP-1 was able to bind acyl-CoA in an in vitro gel-shift assay. Moreover, heterologous RpACBP-1 expression in acb1Δ mutant yeast rescued the multi-lobed vacuole phenotype, indicating that RpACBP-1 acts as a bona fide acyl-CoA-binding protein. RpACBP-1 knockdown using RNAi caused triacylglycerol accumulation in the insect posterior midgut and a reduction in the number of deposited eggs. The amount of stored triacylglycerol was reduced in flight muscle, and the incorporation of fatty acids in cholesteryl esters was increased in the fat body. These results showed that RpACBP-1 participates in several lipid metabolism steps in R. prolixus.
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      PubDate: 2016-03-22T09:36:08Z
       
  • General Odorant-Binding Proteins and sex pheromone guide larvae of
           Plutella xylostella to better food
    • Abstract: Publication date: Available online 19 March 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Jiao Zhu, Liping Ban, Li-Mei Song, Yang Liu, Paolo Pelosi, Guirong Wang
      Olfaction of Lepidopteran larvae has received little attention, compared to the damage to crops done by insects at this stage. We report that larvae of the diamondback moth Plutella xylostella are attracted to their natural sex pheromone and to their major component (Z)-11-hexadecenal, but only in a food context. For such task they use two general odorant-binding proteins (GOBPs), abundantly expressed in the three major sensilla basiconica of the larval antenna, as shown by whole-mount immunostaining and immunocytochemistry experiments. None of the three genes encoding pheromone-binding proteins (PBPs) are expressed at this stage. Both recombinant GOBPs bind (Z)-11-hexadecenal and the corresponding alcohol, but not the acetate. Binding experiments performed with five mutants of GOBP2, where aromatic residues in the binding pocket were replaced with leucine showed that only one or two amino acid substitutions can completely abolish binding to the pheromone shifting the affinity to plant-derived compounds. We hypothesise that detection of their species-specific pheromone may direct larvae to the sites of foraging chosen by their mother when laying eggs, to find better food, as well as to reduce competition with individuals of the same or other species sharing the same host plant. We also provide evidence that GOBP2 is a narrowly tuned binding protein, whose affinity can be easily switched from linear pheromones to branched plants terpenoids, representing a tool better suited for the simple olfactory system of larvae, as compared to the more sophisticated organ of adults.
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      PubDate: 2016-03-22T09:36:08Z
       
  • Know your ABCs: Characterization and gene expression dynamics of ABC
           transporters in the polyphagous herbivore Helicoverpa armigera
    • Abstract: Publication date: Available online 4 March 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Anne Bretschneider, David G. Heckel, Heiko Vogel
      Polyphagous insect herbivores are adapted to many different secondary metabolites of their host plants. However, little is known about the role of ATP-binding cassette (ABC) transporters, a multigene family involved in detoxification processes. To study the larval response of the generalist Helicoverpa armigera (Lepidoptera) and the putative role of ABC transporters, we performed developmental assays on artificial diet supplemented with secondary metabolites from host plants (atropine-scopolamine, nicotine and tomatine) and non-host plants (taxol) in combination with a replicated RNAseq experiment. A maximum likelihood phylogeny identified the subfamily affiliations of the ABC transporter sequences. Larval performance was equal on the atropine-scopolamine diet and the tomatine diet. For the latter we could identify a treatment-specific upregulation of five ABC transporters in the gut. No significant developmental difference was detected between larvae fed on nicotine or taxol. This was also mirrored in the upregulation of five ABC transporters when fed on either of the two diets. The highest number of differentially expressed genes was recorded in the gut samples in response to feeding on secondary metabolites. Our results are consistent with the expectation of a general detoxification response in a polyphagous herbivore. This is the first study to characterize the multigene family of ABC transporters and identify gene expression changes across different developmental stages and tissues, as well as the impact of secondary metabolites in the agricultural pest Helicoverpa armigera.
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      PubDate: 2016-03-08T22:31:43Z
       
  • Comparative Proteomic Analysis of the Saliva of the Rhodnius Prolixus,
           Triatoma Lecticularia and Panstrongylus Herreri Triatomines Reveals a High
           Interespecific Functional Biodiversity
    • Abstract: Publication date: Available online 3 March 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Carlos Emmanuel Montandon, Edvaldo Barros, Pedro Marcus Vidigal, Maria Tays Mendes, Ana Carolina Borella Marfil Anhê, Humberto Josué de Oliveira Ramos, Carlo José Freire de Oliveira, Cláudio Mafra
      Triatomines are hematophagous arthropods that transmit Trypanosoma cruzi and Trypanosoma rangeli. Feeding behavior and pathogen transmission is known to vary between the different species, and this characteristic is directly or indirectly dependent on the bioactive molecules of the saliva that facilitate the vector-host-parasite interaction. Here, we identify, characterize and compare the sialoproteomic (from the Greek sialo: saliva) repertoire of important species of the main triatomine genera in the Americas (Rhodnius prolixus, Triatoma lecticularia and Panstrongylus herreri) to better explain this interaction through two-dimensional electrophoresis and mass spectrometry. We identified 221 proteins, 69 from R. prolixus, 100 from T. lecticularia and 52 from P. herreri. We identified high abundance molecules with a great potential to modulate host defenses and homeostasis, highlighting Nitrophorin-4 (28.7%), Salivary lipocalin-5 (65.2%) and Putative triabin (20.5%) in R. prolixus, T. lecticularia and P. herreri, respectively. We also observed that only a single hypothetical protein is shared among three species, which was not functionally categorized. This study corroborates previous findings with R. prolixus, increasing the knowledge about this species with relevant proteomic information and comparisons with the other two targets of the study, T. lecticularia and P. herreri, for which no studies are available from a proteomics perspective.
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      PubDate: 2016-03-08T22:31:43Z
       
  • CLIPB8 is part of the prophenoloxidase activation system in Anopheles
           gambiae mosquitoes
    • Abstract: Publication date: Available online 27 February 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Xin Zhang, Chunju An, KaraJo Sprigg, Michel Kristin
      In insects and other arthropods the formation of eumelanin (melanization) is a broad spectrum and potent immune response that is used to encapsulate and kill invading pathogens. This immune response is regulated by the activation of prophenoxidase (proPO), which is controlled by proteinase cascades and its serpin inhibitors, together forming the proPO activation system. While the molecular composition of these protease cascades are well understood in insect model systems, major knowledge gaps remain in mosquitoes. Recently, a regulatory unit of melanization in Anopheles gambiae was documented, comprised of the inhibitory serpin-clip-serine proteinase, CLIPB9 and its inhibitor serpin-2 (SRPN2). Partial reversion of SRPN2 phenotypes in melanotic tumor formation and adult survival by SRPN2/CLIPB9 double knockdown suggested other target proteinases of SRPN2 in regulating melanization. Here we report that CLIPB8 supplements the SRPN2/CLIPB9 regulatory unit in controlling melanization in An. gambiae. As with CLIPB9, knockdown of CLIPB8 partially reversed the pleiotropic phenotype induced by SRPN2 silencing with regards to adult survival and melanotic tumor formation. Recombinant SRPN2 protein formed an SDS-stable protein complex with activated recombinant CLIPB8, however did not efficiently inhibit CLIPB8 activity in vitro. CLIPB8 did not directly activate proPO in vitro nor was it able to cleave and activate proCLIPB9. Nevertheless, epistasis analysis using RNAi placed CLIPB8 and CLIPB9 in the same pathway leading to melanization, suggesting that CLIPB8 either acts further upstream of CLIPB9 or is required for activation of a yet to be identified serine proteinase homolog. Taken together, this study identifies CLIPB8 as an additional player in proPO activation cascade and highlights the complexity of the proteinase network that regulates melanization in An. gambiae.
      Graphical abstract image

      PubDate: 2016-03-02T22:21:52Z
       
  • A mode of action of glucosinolate-derived isothiocyanates: Detoxification
           depletes glutathione and cysteine levels with ramifications on protein
           metabolism in Spodoptera littoralis
    • Abstract: Publication date: April 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 71
      Author(s): Verena Jeschke, Jonathan Gershenzon, Daniel Giddings Vassão
      Glucosinolates are activated plant defenses common in the order Brassicales that release isothiocyanates (ITCs) and other hydrolysis products upon tissue damage. The reactive ITCs are toxic to insects resulting in reduced growth, delayed development and occasionally mortality. Generalist lepidopteran larvae often detoxify ingested ITCs via conjugation to glutathione (GSH) and survive on low glucosinolate diets, but it is not known how this process influences other aspects of metabolism. We investigated the impact of the aliphatic 4-methylsulfinylbutyl-ITC (4msob-ITC, sulforaphane) on the metabolism of Spodoptera littoralis larvae, which suffer a significant growth decline on 4msob-ITC-containing diets while excreting ITC-glutathione conjugates and their derivatives in the frass. The most striking effects were a decrease of GSH in midgut tissue and hemolymph due to losses by conjugation to ITC during detoxification, and a decline of the GSH biosynthetic precursor cysteine. Protein content was likewise reduced by ITC treatment suggesting that protein is actively catabolized in an attempt to supply cysteine for GSH biosynthesis. The negative growth and protein effects were relieved by dietary supplementation with cystine. Other consequences of protein breakdown included deamination of amino acids with increased excretion of uric acid and elevated lipid content. Thus metabolic detoxification of ITCs provokes a cascade of negative effects on insects that result in reduced fitness.
      Graphical abstract image

      PubDate: 2016-02-22T21:48:28Z
       
  • Editorial Board
    • Abstract: Publication date: March 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 70




      PubDate: 2016-02-22T21:48:28Z
       
  • Diet dependent metabolic responses in three generalist insect herbivores
           Spodoptera spp
    • Abstract: Publication date: Available online 22 February 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): A. Roy, W.B. Walker, H. Vogel, S. Chattington, M.C. Larsson, P. Anderson, D.G. Heckel, F. Schlyter
      Adaption to dietary changes is critical in the evolution of host plant ranges in polyphagous insects. We compared three taxa of lepidopteran herbivores from the predominantly generalist genus Spodoptera showing different degrees of polyphagy: S. littoralis, with a broad host range including both mono- and dicotyledonous plants, and two S. frugiperda strains [Corn (i.e. maize) (C) and Rice (R)] adapted primarily to different grass species. When feeding on maize we show a lower performance in the broad generalist taxon compared to the grass adapted taxa. Among these taxa, the maize adapted S. frugiperda C-strain generally performed better than the R-strain on maize leaves. On artificial pinto diet, all taxa performed well. Our RNA-Seq analysis of midgut transcriptomes from 3rd instar larvae feeding on maize showed broader transcriptional readjustments in the generalist S. littoralis compared to grass adapted S. frugiperda strains. Substantial alteration in the expression levels of midgut physiological function related transcripts, such as digestive and detoxifying enzymes, transporters, immunity, and peritrophic membrane associated transcripts, existed in all taxa. We found high background expression of UDP-glucosyl transferases, which are known to neutralize maize leaf toxins, in the maize adapted S. frugiperda C-strain, contributing to its fitness on maize compared to the R-strain. Our findings provide evidence for divergent diet specific response of digestive physiology within these Spodoptera taxa. Unexpectedly, the C- and R-strains of S. frugiperda fed on the same diet showed large differences in expression patterns between these two closely related taxa.
      Graphical abstract image

      PubDate: 2016-02-22T21:48:28Z
       
  • How the rice weevil breaks down the pectin network: Enzymatic synergism
           and sub-functionalization
    • Abstract: Publication date: Available online 17 February 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Roy Kirsch, David G. Heckel, Yannick Pauchet
      Pectin is the most complex polysaccharide in nature and highly abundant in plant cell walls and middle lamellae, where it functions in plant growth and development. Phytopathogens utilize plant pectin as an energy source through enzyme-mediated degradation. These pectolytic enzymes include polygalacturonases (PGs) of the GH28 family and pectin methylesterases (PMEs) of the CE8 family. Recently, PGs were also identified in herbivorous insects of the distantly related plant bug, stick insect and Phytophaga beetle lineages. Unlike all other insects, weevils possess PMEs in addition to PGs. To investigate pectin digestion in insects and the role of PMEs in weevils, all PME and PG family members of the rice weevil Sitophilus oryzae were heterologously expressed and functionally characterized. Enzymatically active and inactive PG and PME family members were identified. The loss of activity can be explained by a lack of substrate binding correlating with substitutions of functionally important amino acid residues. We found subfunctionalization in both enzyme families, supported by expression pattern and substrate specificities as well as evidence for synergistic pectin breakdown. Our data suggest that the rice weevil might be able to use pectin as an energy source, and illustrates the potential of both PG and PME enzyme families to functionally diversify after horizontal gene transfer.
      Graphical abstract image

      PubDate: 2016-02-18T21:29:46Z
       
  • Ancestral gene duplication enabled the evolution of multifunctional
           cellulases in stick insects (Phasmatodea)
    • Abstract: Publication date: April 2016
      Source:Insect Biochemistry and Molecular Biology, Volume 71
      Author(s): Matan Shelomi, David G. Heckel, Yannick Pauchet
      The Phasmatodea (stick insects) have multiple, endogenous, highly expressed copies of glycoside hydrolase family 9 (GH9) genes. The purpose for retaining so many was unknown. We cloned and expressed the enzymes in transfected insect cell lines, and tested the individual proteins against different plant cell wall component poly- and oligosaccharides. Nearly all isolated enzymes were active against carboxymethylcellulose, however most could also degrade glucomannan, and some also either xylan or xyloglucan. The latter two enzyme groups were each monophyletic, suggesting the evolution of these novel substrate specificities in an early ancestor of the order. Such enzymes are highly unusual for Metazoa, for which no xyloglucanases had been reported. Phasmatodea gut extracts could degrade multiple plant cell wall components fully into sugar monomers, suggesting that enzymatic breakdown of plant cell walls by the entire Phasmatodea digestome may contribute to the Phasmatodea nutritional budget. The duplication and neofunctionalization of GH9s in the ancestral Phasmatodea may have enabled them to specialize as folivores and diverge from their omnivorous ancestors. The structural changes enabling these unprecedented activities in the cellulases require further study.
      Graphical abstract image

      PubDate: 2016-02-14T07:28:06Z
       
  • Use of chromatin remodeling ATPases as RNAi targets for parental control
           of western corn rootworm (Diabrotica virgifera virgifera) and Neotropical
           Brown stink bug (Euschistus heros)
    • Abstract: Publication date: Available online 10 February 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Elane Fishilevich, Ana M. Vélez, Chitvan Khajuria, Meghan L.F. Frey, Ronda L. Hamm, Haichuan Wang, Greg A. Schulenberg, Andrew J. Bowling, Heather E. Pence, Premchand Gandra, Kanika Arora, Nicholas P. Storer, Kenneth E. Narva, Blair D. Siegfried
      RNA interference (RNAi) is a gene silencing mechanism that is present in animals and plants and is triggered by double stranded RNA (dsRNA) or small interfering RNA (siRNA), depending on the organism. In the western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), RNAi can be achieved by feeding rootworms dsRNA added to artificial diet or plant tissues transformed to express dsRNA. The effect of RNAi depends on the targeted gene function and can range from an absence of phenotypic response to readily apparent responses, including lethality. Furthermore, RNAi can directly affect individuals that consume dsRNA or the effect may be transferred to the next generation. Our previous work described the potential use of genes involved in embryonic development as a parental RNAi technology for the control of WCR. In this study, we describe the use of chromatin-remodeling ATPases as target genes to achieve parental gene silencing in two insect pests, a coleopteran, WCR, and a hemipteran, the Neotropical brown stink bug, Euschistus heros Fabricius (Hemiptera: Pentatomidae). Our results show that dsRNA targeting chromatin-remodeling ATPase transcripts, brahma, mi-2, and iswi strongly reduced the fecundity of the exposed females in both insect species. Additionally, knockdown of chd1 reduced the fecundity of E. heros.
      Graphical abstract image

      PubDate: 2016-02-10T07:13:16Z
       
  • A three amino acid deletion in the transmembrane domain of the nicotinic
           acetylcholine receptor α6 subunit confers high-level resistance to
           spinosad in Plutella xylostella
    • Abstract: Publication date: Available online 6 February 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Jing Wang, Xingliang Wang, Stuart J. Lansdell, Jianheng Zhang, Neil S. Millar, Yidong Wu
      Spinosad is a macrocyclic lactone insecticide that acts primarily at the nicotinic acetylcholine receptors (nAChRs) of target insects. Here we describe evidence that high levels of resistance to spinosad in the diamondback moth (Plutella xylostella) are associated with a three amino acid (3-aa) deletion in the fourth transmembrane domain (TM4) of the nAChR α6 subunit (Pxα6). Following laboratory selection with spinosad, the SZ-SpinR strain of P. xylostella exhibited 940-fold resistance to spinosad. In addition, the selected insect population had 1060-fold cross-resistance to spinetoram but, in contrast, no cross-resistance to abamectin was observed. Genetic analysis indicates that spinosad resistance in SZ-SpinR is inherited as a recessive and autosomal trait, and that the 3-aa deletion (IIA) in TM4 of Pxα6 is tightly linked to spinosad resistance. Because of well-established difficulties in functional expression of cloned insect nAChRs, the analogous resistance-associated deletion mutation was introduced into a prototype nAChR (the cloned human α7 subunit). Two-electrode voltage-clamp recording with wild-type and mutated nAChRs expressed in Xenopus laevis oocytes indicated that the mutation causes a complete loss of agonist activation. In addition, radioligand binding studies indicated that the 3-aa deletion resulted in significantly lower-affinity binding of the extracellular neurotransmitter-binding site. These findings are consistent with the 3-amino acid (IIA) deletion within the transmembrane domain of Pxα6 being responsible for target-site resistance to spinosad in the SZ-SpinR strain of P. xylostella.
      Graphical abstract image

      PubDate: 2016-02-10T07:13:16Z
       
  • The putative role of Rhipicephalus microplus salivary serpins in the
           tick-host relationship
    • Abstract: Publication date: Available online 2 February 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Lucas Tirloni, Tae Kwon Kim, Mariana Loner Coutinho, Abid Ali, Adriana Seixas, Carlos Termignoni, Albert Mulenga, Itabajara da Silva Vaz
      Inflammation and haemostasis are part of the host's first line of defense to tick feeding. These systems are in part serine protease mediated and are tightly controlled by their endogenous inhibitors, in the serpin superfamily (serine protease inhibitors). From this perspective ticks are thought to use serpins to evade host defenses during feeding. The cattle tick Rhipicephalus microplus encodes at least 24 serpins, of which RmS-3, RmS-6, and RmS-17 were previously identified in saliva of this tick. In this study, we screened inhibitor functions of these three saliva serpins against a panel of 16 proteases across the mammalian defense pathway. Our data confirm that Pichia pastoris-expressed rRmS-3, rRmS-6, and rRmS-17 are likely inhibitors of pro-inflammatory and pro-coagulant proteases. We show that rRmS-3 inhibited chymotrypsin and cathepsin G with stoichiometry of inhibition (SI) indices of 1.8 and 2.0, and pancreatic elastase with SI higher than 10. Likewise, rRmS-6 inhibited trypsin with SI of 2.6, chymotrypsin, factor Xa, factor XIa, and plasmin with SI higher than 10, while rRmS-17 inhibited trypsin, cathepsin G, chymotrypsin, plasmin, and factor XIa with SI of 1.6, 2.6, 2.7, 3.4, and 9.0, respectively. Additionally, we observed the formation of irreversible complexes between rRmS-3 and chymotrypsin, rRmS-6/rRmS-17 and trypsin, and rRmS-3/rRmS-17 and cathepsin G, which is consistent with typical mechanism of inhibitory serpins. In blood clotting assays, rRmS-17 delayed plasma clotting by 60 s in recalcification time assay, while rRmS-3 and rRmS-6 did not have any effect. Consistent with inhibitor function profiling data, 2.0 μM rRmS-3 and rRmS-17 inhibited cathepsin G-activated platelet aggregation in a dose-responsive manner by up to 96% and 95% respectively. Of significant interest, polyclonal antibodies blocked inhibitory functions of the three serpins. Also notable, antibodies to Amblyomma americanum, Ixodes scapularis, and R. sanguineus tick saliva proteins cross-reacted with the three R. microplus saliva serpins, suggesting the potential of these proteins as candidates for universal anti-tick vaccines.
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      PubDate: 2016-02-10T07:13:16Z
       
  • Potential detoxification of gossypol by UDP-glycosyltransferases in the
           two Heliothine moth species Helicoverpa armigera and Heliothis virescens
    • Abstract: Publication date: Available online 10 February 2016
      Source:Insect Biochemistry and Molecular Biology
      Author(s): Corinna Krempl, Theresa Sporer, Michael Reichelt, Seung-Joon Ahn, Hanna Heidel-Fischer, Heiko Vogel, David G. Heckel, Nicole Joußen
      The cotton bollworm Helicoverpa armigera and the tobacco budworm Heliothis virescens are closely related generalist insect herbivores and serious pest species on a number of economically important crop plants including cotton. Even though cotton is well defended by its major defensive compound gossypol, a toxic sesquiterpene dimer, larvae of both species are capable of developing on cotton plants. In spite of severe damage larvae cause on cotton plants, little is known about gossypol detoxification mechanisms in cotton-feeding insects. Here, we detected three monoglycosylated and up to five diglycosylated gossypol isomers in the feces of H. armigera and H. virescens larvae fed on gossypol-supplemented diet. Candidate UDP-glycosyltransferase (UGT) genes of H. armigera were selected by microarray studies and in silico analyses and were functionally expressed in insect cells. In enzymatic assays, we show that UGT41B3 and UGT40D1 are capable of glycosylating gossypol mainly to the diglycosylated gossypol isomer 5 that is characteristic for H. armigera and is absent in H. virescens feces. In conclusion, our results demonstrate that gossypol is partially metabolized by UGTs via glycosylation, which might be a crucial step in gossypol detoxification in generalist herbivores utilizing cotton as host plant.
      Graphical abstract image

      PubDate: 2016-02-10T07:13:16Z
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
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