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Lepidopteran Insect (lepidopteran + insect)
Selected AbstractsProteolytic activation and function of the cytokine Spätzle in the innate immune response of a lepidopteran insect, Manduca sextaFEBS JOURNAL, Issue 1 2010Chunju An The innate immune response of insects includes induced expression of genes encoding a variety of antimicrobial peptides. The signaling pathways that stimulate this gene expression have been well characterized by genetic analysis in Drosophila melanogaster, but are not well understood in most other insect species. One such pathway involves proteolytic activation of a cytokine called Spätzle, which functions in dorsal,ventral patterning in early embryonic development and in the antimicrobial immune response in larvae and adults. We have investigated the function of Spätzle in a lepidopteran insect, Manduca sexta, in which hemolymph proteinases activated during immune responses have been characterized biochemically. Two cDNA isoforms for M. sexta Spätzle-1 differ because of alternative splicing, resulting in a 10 amino acid residue insertion in the pro-region of proSpätzle-1B that is not present in proSpätzle-1A. The proSpätzle-1A cDNA encodes a 32.7 kDa polypeptide that is 23% and 44% identical to D. melanogaster and Bombyx mori Spätzle-1, respectively. Recombinant proSpätzle-1A was a disulfide-linked homodimer. M. sexta hemolymph proteinase 8 cleaved proSpätzle-1A to release Spätzle-C108, a dimer of the C-terminal 108 residue cystine-knot domain. Injection of Spätzle-C108, but not proSpätzle-1A, into larvae stimulated expression of several antimicrobial peptides and proteins, including attacin-1, cecropin-6, moricin, lysozyme, and the immunoglobulin domain protein hemolin, but did not significantly affect the expression of two bacteria-inducible pattern recognition proteins, immulectin-2 and ,-1,3-glucan recognition protein-2. The results of this and other recent studies support a model for a pathway in which the clip-domain proteinase pro-hemolymph proteinase 6 becomes activated in plasma upon exposure to Gram-negative or Gram-positive bacteria or to ,-1,3-glucan. Hemolymph proteinase 6 then activates pro-hemolymph proteinase 8, which in turn activates Spätzle-1. The resulting Spätzle-C108 dimer is likely to function as a ligand to activate a Toll pathway in M. sexta as a response to a wide variety of microbial challenges, stimulating a broad response to infection. Structured digital abstract ,,MINT-7295125: Spätzle 1A (uniprotkb:C8BMD1) and Spätzle 1A (uniprotkb:C8BMD1) bind (MI:0407) by comigration in gel electrophoresis (MI:0807) [source] Induction of the white egg 3 mutant phenotype by injection of the double-stranded RNA of the silkworm white geneINSECT MOLECULAR BIOLOGY, Issue 3 2002G. X. Quan Abstract Injection of double-stranded RNA (dsRNA) corresponding to the silkworm white gene (Bmwh3) into preblastoderm eggs of the wild-type silkworm induced phenotypes similar to those observed with mutants of the white egg 3 locus (10,19.6). The induced phenotypes were characterized by the presence of white eggs and translucent larval skin. Northern analysis showed that the expression of the endogenous Bmwh3 gene in the injected embryos was distinctly depressed. Furthermore, the injection of the GFP dsRNA inhibited the expression of the GFP gene from a plasmid co-injected with the dsRNA but did not depress the expression of the Bmwh3 gene. These findings demonstrate that sequence-specific RNA interference occurred in the silkworm. We conclude from the results that the RNA interference can be applied as a tool for the analysis of the gene function in the lepidopteran insects. [source] Pheromone blends and trap designs can affect catches of Sesamia nonagrioides Lef. (Lep., Noctuidae) males in maize fieldsJOURNAL OF APPLIED ENTOMOLOGY, Issue 1-2 2001A. Ameline Among lepidopteran insects, the female-produced sex pheromones are the most widely used chemical stimuli for pest management by (i) mating disruption, and (ii) monitoring adult insect populations in agricultural crops. Sesamia nonagrioides is one of the main pests on maize crops around the Mediterranean area and monitoring adult populations with synthetic sex pheromone is of great interest. The technique used involved field trapping with synthetic pheromone blend. The reliability of the technique is directly related to the trap shape and pheromone blends. Universal Moth Trap® (UM trap, Biosyste,mes, France) and Service Régional de la Protection des Végétaux (SRPV) traps baited with either synthetic pheromone blend or virgin females were evaluated in two commercial maize fields (var.cecilia) (Belleserre, Tarn. France) to determine the potential use of synthetic lures in monitoring S. nonagrioides populations in maize field. The study showed that SRPV traps baited with synthetic pheromone blend caught significantly more S. nonagrioides males than UM traps baited with the same blend, indicating the efficiency of the SRPV traps in monitoring field population of S. nonagrioides. The study also showed that the synthetic pheromone-baited SRPV trap caught three times less adult males than the same traps baited with virgin females indicating that the synthetic blend was less attractive than the natural blend released by virgin females. However, despite the lower number of catches in the SRPV traps baited with synthetic pheromones, there was a significant and positive relationship between the number of catches in SRPV traps baited with the synthetic pheromone and with the females. This result indicates that synthetic pheromones can be used as baits in SRPV traps to monitor S. nonagrioides adult population in commercial maize crops. Nevertheless, to use the synthetic pheromone to monitor S. nonagrioides population effectively in the field, further refinement and improvement of the synthetic blend should be carried out in order to obtain a blend that is equally as attractive as the natural blend released by virgin females. [source] | ||||||||||