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aminopeptidase coleoptera

Estefanía Contreras, Michael Schoppmeier, M Dolores Real, Carolina Rausell
Understanding how Bacillus thuringiensis (Bt) toxins interact with proteins in the midgut of susceptible coleopteran insects is crucial to fully explain the molecular bases of Bt specificity and insecticidal action. In this work, aminopeptidase N (TcAPN-I), E-cadherin (TcCad1), and sodium solute symporter (TcSSS) have been identified by ligand blot as putative Cry3Ba toxin-binding proteins in Tribolium castaneum (Tc) larvae. RNA interference knockdown of TcCad1 or TcSSS proteins resulted in decreased susceptibility to Cry3Ba toxin, demonstrating the Cry toxin receptor functionality for these proteins...
June 21, 2013: Journal of Biological Chemistry
Jorge Eduardo Cortázar Gómez, Silvio Alejandro López-Pazos, Jairo Cerón
An emergent pest is the weevil Asymmathetes vulcanorum, an insect that attacks Colombian potato areas. Here, some Cry proteins from the entomopathogenic bacteria Bacillus thuringiensis were evaluated as biological control strategy. It was found that Cry1B protoxin caused a mortality of 40% with a dose of 8000 ng/cm(2). Also in this research, it was identified a full length cDNA of an aminopeptidase N, a possible Cry protein receptor located in the insect midgut. This is the first report about B. thuringiensis as an alternative method for control of A...
September 15, 2012: Journal of Invertebrate Pathology
H S Gatehouse, B Tan, J T Christeller, M R H Hurst, S D G Marshall, T A Jackson
Amber disease of the New Zealand grass grub Costelytra zealandica (Coleoptera: Scarabaeidae) is caused by ingestion of pADAP plasmid carrying isolates of Serratia entomophila or Serratia proteamaculans (Enterobacteriaceae) and causes infected larvae to cease feeding and clear their midgut to a pale amber colour where midgut serine protease activities are virtually eliminated. Using bacterial strains and mutants expressing combinations of the anti-feeding (afp) and gut clearance (sep) gene clusters from pADAP, we manipulated the disease phenotype and demonstrated directly the relationship between gene clusters, phenotype and loss of enzyme activity...
July 2009: Journal of Invertebrate Pathology
Yannick Pauchet, Paul Wilkinson, Manuella van Munster, Sylvie Augustin, David Pauron, Richard H ffrench-Constant
The insect midgut is the primary target site for Bt-derived insecticides and Bt alternatives. However, despite extensive recent study, the precise role and nature of different Bt receptors remains a subject of considerable debate. This problem is fuelled by a lack of understanding of the genes expressed in the insect midgut and their physiological roles. The poplar leaf beetle, Chrysomela tremulae, is an important model for understanding the mode of action of, and resistance to, coleopteran-specific Bt toxins and currently shows the only known naturally occurring case of resistance to Cry3A toxins...
May 2009: Insect Biochemistry and Molecular Biology
Natasa Bozić, Jelisaveta Ivanović, Vera Nenadović, Jörgen Bergström, Thomas Larsson, Zoran Vujcić
The major leucyl aminopeptidase (LAP) from the midgut of Morimus funereus larvae was purified and characterised. Specific LAP activity was increased 292-fold by purification of the crude midgut extract. The purified enzyme had a pH optimum of 7.5 (optimum pH range 7.0-8.5) and preferentially hydrolysed p-nitroanilides containing hydrophobic amino acids in the active site, with the highest V(max)/K(M) ratio for leucine-p-nitroanilide (LpNA). Among a number of inhibitors tested, the most efficient were 1,10-phenanthroline having a K(i) value of 0...
March 2008: Comparative Biochemistry and Physiology. Part B, Biochemistry & Molecular Biology
A H P Ferreira, P T Cristofoletti, D M Lorenzini, L O Guerra, P B Paiva, M R S Briones, W R Terra, C Ferreira
The objective of this study was to identify midgut microvillar proteins in insects appearing earlier (Coleoptera) and later (Lepidoptera) in evolution. For this, cytoskeleton-free midgut microvillar membrane from Spodoptera frugiperda (Lepidoptera) and Tenebrio molitor (Coleoptera) were used to raise antibodies. These were used for screening midgut cDNA expression libraries. Positive clones were sequenced, assembled and searched for similarities with gene/protein databases. The predicted midgut microvillar proteins from T...
November 2007: Journal of Insect Physiology
Waldir Caldeira, Alcides B Dias, Walter R Terra, Alberto F Ribeiro
Bostrichiformia is the less known major series of Coleoptera regarding digestive physiology. The midgut of Dermestes maculatus has a cylindrical ventriculus with anterior caeca. There is no cell differentiation along the ventriculus, except for the predominance of cells undergoing apocrine secretion in the anterior region. Apocrine secretion affects a larger extension and a greater number of cells in caeca than in ventriculus. Ventricular cells putatively secrete digestive enzymes, whereas caecal cells are supposed to secrete peritrophic gel (PG) glycoproteins...
January 2007: Archives of Insect Biochemistry and Physiology
Trevor A Jackson, John T Christeller, Jane Z McHenry, William A Laing
Amber disease in the grass grub (Costelytra zealandica White) (Coleoptera: Scarabaeidae), caused by strains of the bacteria Serratia entomophila or S. proteamaculans, is characterised by cessation of feeding and clearance of the midgut. Analysis of the midgut enzyme activity in diseased grass grub larvae showed that proteolytic activity was reduced to low levels. The endopeptidases, trypsin, elastase, and chymotrypsin, were all markedly reduced in activity whereas the exopeptidases (leucine-aminopeptidase and carboxypeptidase A and B) were much less affected...
July 2004: Journal of Invertebrate Pathology
Natasa Bozić, Zoran Vujcić, Vera Nenadović, Jelisaveta Ivanović
Exopeptidases of Morimus funereus larvae were partially purified and characterized. Specific leucyl aminopeptidase (LAP) activity was increased eight-fold by gel filtration of the crude midgut extract. The partially purified LAP had a molecular mass greater than 100 kDa with pH optima from 7.0-9.0 and no strict substrate specificity. M. funereus LAP preferentially hydrolyzed p-nitroanilides with hydrophobic amino acids in the active site, with a K(m) for leucine-p-nitroanilide of 0.21 mM. Zymogram analysis of an electropherogram obtained by native polyacrylamide gel electrophoresis revealed four enzymatically active proteinases using leucine-p-nitroanilide and methionine-p-nitroanilide as substrates and two enzymatically active proteinases using lysine-p-nitroanilide as a substrate...
February 2003: Comparative Biochemistry and Physiology. Part B, Biochemistry & Molecular Biology
Wolfgang Wagner, Frank Möhrlen, Wolfgang Schnetter
In previous studies we showed that the resistance of the European Cockchafer, Melolontha melolontha, towards the Scarab specific Cry8C toxin of Bacillus thuringiensis japonensis strain Buibui is due to the complexity of proteinases in the midgut of the pest insect. In this study these proteinases were identified and characterized using a combination of synthetic substrates and specific inhibitors in zymograms, activity blots, and photometric/fluorometric assays. In the midgut juice three trypsin-like and three elastase-like serine proteinases are predominantly present...
July 2002: Insect Biochemistry and Molecular Biology
P T Cristofoletti, W R Terra
Aminopeptidases are major enzymes in the midgut microvillar membranes of most insects and are targets of insecticidal Bacillus thuringiensis crystal delta-endotoxins. Sequence analysis and substrate specificity studies showed that these enzymes resemble mammalian aminopeptidase N, although information on the organization of their active site is lacking. The effect of pH at different temperatures on the kinetic parameters of Tenebrio molitor (Coleoptera) larval aminopeptidase showed that enzyme catalysis depend on a deprotonated (pK 7...
June 15, 2000: Biochimica et Biophysica Acta
C Girard, M Le Métayer, M Bonadé-Bottino, M H Pham-Delègue, L Jouanin
Incorporation of genes encoding proteinase inhibitors into oilseed rape genome could confer resistance to Coleoptera, which are the major pests on rape in Europe. A detailed study of the digestive proteinase of a model cruciferous-feeding Coleoptera, Phaedon cochleariae, showed that this insect relies on a complex proteolytic system including serine, cysteine, aspartyl proteinases, and leucine aminopeptidases. The inhibition of general and specific activities by a range of proteinase inhibitors in vitro suggested that oryzacystatin I (OCI) and Bowman-Birk inhibitor (BBI) would have adverse effects when ingested by the larvae...
April 1998: Insect Biochemistry and Molecular Biology
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