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RNAi of ace1 and ace2 in Blattella germanica reveals their differential contribution to acetylcholinesterase activity and sensitivity to insecticides.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study we tested the hypothesis that the two ace paralogous from Blattella germanica have different contributions to AChE activity, using RNA interference (RNAi) to knockdown each one individually. Paralogous-specific depletion of Bgace transcripts was evident in ganglia of injected cockroaches, although the effects at the protein level were less pronounced. Using spectrophotometric and zymogram measurements, we obtained evidence that BgAChE1 represents 65-75% of the total AChE activity in nerve tissue demonstrating that ace1 encodes a predominant AChE. A significant increase in sensitivity of Bgace1-interfered cock...
Source: Insect Biochemistry and Molecular Biology - November 6, 2009 Category: Biochemistry Authors: Revuelta L, Piulachs MD, Bellés X, Castañera P, Ortego F, Díaz-Ruíz JR, Hernández-Crespo P, Tenllado F Tags: Insect Biochem Mol Biol Source Type: journals

Chymotrypsin-like peptidases from Tribolium castaneum: a role in molting revealed by RNA interference.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Chymotrypsin-like peptidases (CTLPs) of insects are primarily secreted into the gut lumen where they act as digestive enzymes. We studied the gene family encoding CTLPs in the genome of the red flour beetle, Tribolium castaneum. Using an extended search pattern, we identified 14 TcCTLP genes that encode peptidases with S1 specificity pocket residues typically found in chymotrypsin-like enzymes. We further analyzed the expression patterns of seven TcCTLP genes at various developmental stages. While some TcCTLP genes were exclusively expressed in feeding larval and adult stages (TcCTLP-5A/B, TcCTLP-6A), others were also ...
Source: Insect Biochemistry and Molecular Biology - November 5, 2009 Category: Biochemistry Authors: Broehan G, Arakane Y, Beeman RW, Kramer KJ, Muthukrishnan S, Merzendorfer H Tags: Insect Biochem Mol Biol Source Type: journals

Molecular Genetic Analysis of Midgut Serine Proteases in Aedes aegypti Mosquitoes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Digestion of blood meal proteins by midgut proteases provides anautogenous mosquitoes with the nutrients required to complete the gonotrophic cycle. Inhibition of protein digestion in the midgut of blood feeding mosquitoes could therefore provide a strategy for population control. Based on recent reports indicating that the mechanism and regulation of protein digestion in blood fed female Aedes aegypti mosquitoes is more complex than previously thought, we used a robust RNAi knockdown method to investigate the role of four highly expressed midgut serine proteases in blood meal metabolism. We show by Western blotting th...
Source: Insect Biochemistry and Molecular Biology - October 30, 2009 Category: Biochemistry Authors: Isoe J, Rascón AA, Kunz S, Miesfeld RL Tags: Insect Biochem Mol Biol Source Type: journals

Cell cycle arrest as a hallmark of insect diapause: Changes in gene transcription during diapause induction in the drosophilid fly, Chymomyza costata.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The division cycle of CNS cells was arrested in G0/G1 (86.6%) and G2 (12.8%) phases in diapausing larvae of Chymomyza costata. A two-step response was observed when the diapause was induced by transfering the 3rd instar larvae from long-day to short-day conditions: first, the proportion of G2-arrested cells increased rapidly within a single day after transfer; and second, the increase of G0/G1-arrested cells started with a delay of five days after transfer. The changes of relative mRNA levels of seven different genes, which code for important cell cycle regulatory factors [Cyclins D and E, kinases Wee1 and Myt1, phosph...
Source: Insect Biochemistry and Molecular Biology - October 28, 2009 Category: Biochemistry Authors: Koštál V, Simůnková P, Kobelková A, Shimada K Tags: Insect Biochem Mol Biol Source Type: journals

Multiple duplications of the rare ace-1 mutation F290V in Culex pipiens natural populations.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We described here a biochemical method that rapidly identifies AChE1 variants (susceptible, G119S and F290V, named S, R and V, respectively) present in individual mosquitoes. We investigated the frequency of AChE1 phenotypes in 41 field samples collected around the Mediterranean Sea. F290V substitution was found only in 15 samples and at low frequency, whereas G119S was highly spread in all samples. However, seven V distinct alleles were identified whereas only one R allele was present. The [V] enzymatic phenotype was never observed alone, and the V allele was always found associated with the susceptible and/or G119S AChE1...
Source: Insect Biochemistry and Molecular Biology - October 26, 2009 Category: Biochemistry Authors: Alout H, Labbé P, Berthomieu A, Pasteur N, Weill M Tags: Insect Biochem Mol Biol Source Type: journals

BmCAP, a silkmoth gene encoding multiple protein isoforms characterized by SoHo and SH3 domains: Expression analysis during ovarian follicular development.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
CAP/ArgBP2/vinexin family proteins, adaptor proteins characterised by three SH3 domains at their C-termini and a SoHo domain towards their N-termini, are known to regulate cell adhesion, cytoskeletal organization, and growth factor signalling. Here we present the isolation and ovarian expression of the BmCAP gene which encodes CAP/ArgBP2/vinexin family proteins in the silkmoth, Bombyx mori. Screening for full-length cDNA clones identified three mRNA isoforms, BmCAP-A1, BmCAP-A2 and BmCAP-B, which show expression throughout ovarian follicular development. Using an antibody raised against a unique region between the SoHo...
Source: Insect Biochemistry and Molecular Biology - October 24, 2009 Category: Biochemistry Authors: Georgomanolis T, Iatrou K, Swevers L Tags: Insect Biochem Mol Biol Source Type: journals

Direct evidence of the cyclooxygenase pathway of prostaglandin synthesis in arthropods: Genetic and biochemical characterization of two crustacean cyclooxygenases.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Prostaglandins, well-known lipid mediators in vertebrate animals, have also shown to play certain regulatory roles in insects and other arthropods acting on reproduction, immune system and ion transport. However, knowledge of their biosynthetic pathways in arthropods is lacking. In the present study, we report the cloning and expression of cyclooxygenase (COX) from amphipod crustaceans Gammarus spp and Caprella spp. The amphipod COX proteins contain key residues shown to be important for cyclooxygenase and peroxidase activities. Differently from all other known cyclooxygenases the N-terminal signal sequence of amphipod...
Source: Insect Biochemistry and Molecular Biology - October 23, 2009 Category: Biochemistry Authors: Varvas K, Kurg R, Hansen K, Järving R, Järving I, Valmsen K, Lõhelaid H, Samel N Tags: Insect Biochem Mol Biol Source Type: journals

Purification, characterization and sequencing of the major beta-1,3-glucanase from the midgut of Tenebrio molitor larvae.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The major beta-1,3-glucanase from Tenebrio molitor (TLam) was purified to homogeneity (yield, 6%; enrichment, 113 fold; specific activity, 4.4 U/mg). TLam has a molecular weight of 50 kDa and a pH optimum of 6. It is an endoglucanase that hydrolyzes beta-1,3-glucans as laminarin and yeast beta-1,3-1,6-glucan, but is inactive towards other polysaccharides (as linear beta-1,3 glucans or mixed beta-1,3-1,4-glucan from cereals) or disaccharides. The enzyme is not inhibited by high substrate concentrations and has low processivity (0.6). TLam has two ionizable groups involved in catalysis, and His, Tyr and Arg residues plus...
Source: Insect Biochemistry and Molecular Biology - October 15, 2009 Category: Biochemistry Authors: Genta FA, Bragatto I, Terra WR, Ferreira C Tags: Insect Biochem Mol Biol Source Type: journals

Molecular cloning and pharmacological characterization of a Bombyx mori tyramine receptor selectively coupled to intracellular calcium mobilization.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Tyramine (TA) is a biogenic amine in invertebrates. cDNA encoding the TA receptor (TAR) BmTAR2 was cloned from the nerve tissue of the silkworm Bombyx mori. The receptor's functional and pharmacological properties were examined in BmTAR2-transfected HEK-293 cells. In [(3)H]TA binding assays, BmTAR2 showed considerably higher affinity for TA than for other biogenic amines, with an IC(50) value of 57.5nM. Moreover, TA induced a dose-dependent increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) in cells, with an EC(50) value of 11.6nM, whereas octopamine and dopamine increased [Ca(2+)](i) only at concentrations a...
Source: Insect Biochemistry and Molecular Biology - October 11, 2009 Category: Biochemistry Authors: Huang J, Ohta H, Inoue N, Takao H, Kita T, Ozoe F, Ozoe Y Tags: Insect Biochem Mol Biol Source Type: journals

Specific loops D, E and F of nicotinic acetylcholine receptor beta1 subunit may confer imidacloprid selectivity between Myzus persicae and its predatory enemy Pardosa pseudoannulata.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study contributes to our understanding of the molecular mechanism underlying selectivity of neonicotinoids against insects over spiders. PMID: 19818849 [PubMed - as supplied by publisher] (Source: Insect Biochemistry and Molecular Biology)
Source: Insect Biochemistry and Molecular Biology - October 6, 2009 Category: Biochemistry Authors: Song F, You Z, Yao X, Cheng J, Liu Z, Lin K Tags: Insect Biochem Mol Biol Source Type: journals

Ingested double-stranded RNAs can act as species-specific insecticides.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A serious shortcoming of many insecticides is that they can kill non-target species. To address this issue, we harnessed the sequence-specificity of RNA interference (RNAi) to design orally-delivered double-stranded (ds) RNAs that selectively killed target species. Fruit flies (Drosophila melanogaster), flour beetles (Tribolium castaneum), pea aphids (Acyrthosiphon pisum), and tobacco hornworms (Manduca sexta) were selectively killed when fed species-specific dsRNA targeting vATPase transcripts. We also demonstrate that even closely related species can be selectively killed by feeding on dsRNAs that target the more var...
Source: Insect Biochemistry and Molecular Biology - October 4, 2009 Category: Biochemistry Authors: Whyard S, Singh AD, Wong S Tags: Insect Biochem Mol Biol Source Type: journals

Sequence and function of lysosomal and digestive cathepsin D-like proteinases of Musca domestica midgut enzymes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
M. domestica larvae display in anterior and middle midgut contents, a proteolytic activity with pH optimum of 3.0-3.5 and kinetic properties like cathepsin D. Three cDNAs coding for preprocathepsin D-like proteinases (ppCAD 1, ppCAD 2, ppCAD 3) were cloned from a M. domestica midgut cDNA library. The coded protein sequences included the signal peptide, propeptide and mature enzyme that has all conserved catalytic and substrate binding residues found in bovine lysosomal cathepsin D. Nevertheless, ppCAD 2 and ppCAD3 lack the characteristic proline loop and glycosylation sites. A comparison among the sequences of cathepsi...
Source: Insect Biochemistry and Molecular Biology - October 4, 2009 Category: Biochemistry Authors: Padilha MH, Pimentel AC, Ribeiro AF, Terra WR Tags: Insect Biochem Mol Biol Source Type: journals

Does Corazonin signal nutrional stress in insects ?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The undecapeptide corazonin, initially discovered from the American cockroach as a strong cardioaccelerator, is now known to be ubiquitously present in arthropods, although it is absent from some species, notably Coleoptera. The structure of its precursor is similar to the GnRH precursor, while it acts through a receptor related to the GnRH receptor; corazonin thus appears to be an arthropod homolog of GnRH. It is produced by neuroendocrine cells in the brain, as well as interneurons in the ventral nerve cord. These two cell types are generally present in insects; in most species there are also other neurons producing ...
Source: Insect Biochemistry and Molecular Biology - October 4, 2009 Category: Biochemistry Authors: Veenstra JA Tags: Insect Biochem Mol Biol Source Type: journals

The discovery of a novel sodium channel in the cockroach Periplaneta americana: Evidence for an early duplication of the para-like gene.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Voltage-gated sodium channels (Na(v) channels) belong to a superfamily of ion channels which play an essential role in membrane excitability. Only one gene encoding voltage-gated sodium channels (Na(v) channels) has been characterized so far in insects. Here, we have cloned one full-length cDNA encoding a conventional insect Na(v) channel (PaNa(v)1) and two full-length cDNAs encoding putative insect Na(v) channels (PaFPC1 and PaFPC2) in Periplaneta americana, a model insect for neurophysiological studies. The ORFs of PaFPC1 and PaFPC2 contained 4662 bp and encoded 1553 amino acid residues, and the ORF of PaNa(v)1 conta...
Source: Insect Biochemistry and Molecular Biology - September 30, 2009 Category: Biochemistry Authors: Moignot B, Lemaire C, Quinchard S, Lapied B, Legros C Tags: Insect Biochem Mol Biol Source Type: journals

A peptidomics study reveals the impressive antimicrobial peptide arsenal of the wax moth Galleria mellonella.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study shows that G. mellonella can concurrently release an impressive array of at least 18 known or putative antimicrobial peptides from 10 families to defend itself against invading microbes. PMID: 19786100 [PubMed - as supplied by publisher] (Source: Insect Biochemistry and Molecular Biology)
Source: Insect Biochemistry and Molecular Biology - September 24, 2009 Category: Biochemistry Authors: Brown SE, Howard A, Kasprzak AB, Gordon KH, East PD Tags: Insect Biochem Mol Biol Source Type: journals

Aphidius ervi teratocytes release an extracellular enolase.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report the cloning of a gene and the characterization of the encoded protein, which is released by the teratocytes of the parasitoid Aphidius ervi in the haemocoel of the host aphid Acyrthosiphon pisum. The studied protein was identified by LC-MS/MS, and the gathered information used for isolating the full length cDNA. The corresponding gene was made of 3 exons and 2 introns, and was highly expressed in the adult wasps and in parasitized hosts. The translation product, which was named Ae-ENO, showed a very high level of sequence identity with insect enolases. In vivo immunodetection experiments evidenced Ae-ENO localiza...
Source: Insect Biochemistry and Molecular Biology - September 24, 2009 Category: Biochemistry Authors: Falabella P, Riviello L, De Stradis ML, Stigliano C, Varricchio P, Grimaldi A, de Eguileor M, Graziani F, Gigliotti S, Pennacchio F Tags: Insect Biochem Mol Biol Source Type: journals

Glycerol kinase activity and glycerol kinase-3 gene are up-regulated by acclimation to 5 degrees C in diapause eggs of the silkworm, Bombyx mori.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we detected glycerol kinase activity in diapause-terminated eggs and then characterized its properties; maximal activity was seen at pH 8.5-9.0, and Km values for glycerol and ATP were 0.32 and 0.095 mM, respectively. In diapause eggs continuously kept at 25 degrees C, the activity was almost negligible. However, activity was seen after chilling for 60 days and thereafter increased when the eggs were exposed to 5 degrees C after 2 days post-oviposition, indicating that glycerol kinase is a rate-limiting enzyme in glycerol utilization. We then cloned cDNAs encoding glycerol kinase-1, -2 and -3 from B. mori. O...
Source: Insect Biochemistry and Molecular Biology - September 9, 2009 Category: Biochemistry Authors: Kihara F, Itoh K, Iwasaka M, Niimi T, Yamashita O, Yaginuma T Tags: Insect Biochem Mol Biol Source Type: journals

The Adipokinetic Hormone system in culicinae (Diptera: Culicidae): Molecular identification and characterization of two Adipokinetic Hormone (AKH) precursors from Aedes aegypti and Culex pipiens and two putative AKH receptor variants from Aedes aegypti.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we identified and analyzed the genes encoding two AKH preprohormones in the Yellow fever mosquito, Aedes aegypti: Aedae-AKH-I encodes the octapeptide pELFTPSWa and Aedae-AKH-II the decapeptide pEVTFSRDWNAa. Identical AKHs were identified in the West Nile virus vector, Culex pipiens, whose genes were characterized in this study as Culpi-AKH-I and Culpi-AKH-II. Using Northern blot, transcript expression was shown in A. aegypti, for Aedae-AKH-I in the head/thorax tissues of pupae and females, as well as in the abdomen of adult males; Aedae-AKH-II was only expressed in adults. In an immunocytological study using...
Source: Insect Biochemistry and Molecular Biology - September 9, 2009 Category: Biochemistry Authors: Kaufmann C, Merzendorfer H, Gäde G Tags: Insect Biochem Mol Biol Source Type: journals

Identification and characterization of eleven glutathione S-transferase genes from the aquatic midge Chironomus tentans (Diptera: Chironomidae).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Eleven cDNAs encoding glutathione S-transferases (GSTs) were sequenced and characterized in Chironomus tentans, an ecologically important aquatic midge. Phylogenetic analysis revealed seven GSTs in three different cytosolic classes including 4 in sigma (CtGSTs1, CtGSTs2, CtGSTs3, CtGSTs4), 2 in delta (CtGSTd1, CtGSTd2), and 1 in omega (CtGSTo1). The remaining four GSTs (CtGSTu1, CtGSTu2, CtGSTu3, CtGSTu4) were unclassified due to their low relatedness to currently known classes of insect GSTs. Reverse-transcription (RT)-PCR analysis of the 11 GST genes showed that CtGSTd1, CtGSTu2, CtGSTu4, CtGSTs1, CtGSTs2, CtGSTs3, C...
Source: Insect Biochemistry and Molecular Biology - September 6, 2009 Category: Biochemistry Authors: Li X, Zhang X, Zhang J, Zhang X, Starkey SR, Zhu KY Tags: Insect Biochem Mol Biol Source Type: journals

The Pandinus imperator haemolymph lipoprotein, an unusual phosphatidylserine carrying lipoprotein.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The haemolymph lipoprotein of the scorpion, Pandinus imperator was isolated and characterised. Contrary to the lipoproteins of insects and the discoidal HDL-lipoproteins of a crayfish and polychaete, the Pandinus lipoprotein consists of three instead of two apoproteins (apoPiLp I = 230kDa, apoPiLp II = 130kDa and apoPiLp III = 120kDa). The apolipoproteins are arranged in varying stoichiometries as judged by cross linking experiments. In lipoprotein samples from individual animals, the two smaller subunits to occurred in a 1:1 stoichiometry, while the relative amount of the 230kDa peptide varied. The lipoprotein is a sl...
Source: Insect Biochemistry and Molecular Biology - August 30, 2009 Category: Biochemistry Authors: Schenk S, Gras H, Marksteiner D, Patasic L, Prommnitz B, Hoeger U Tags: Insect Biochem Mol Biol Source Type: journals

Midgut cysteine protease inhibiting activity in Trichoplusia ni protects the peritrophic membrane from degradation by plant cysteine proteases.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, results from this study uncovered that herbivorous insects may counteract the attack of plant cysteine proteases on the PM by inhibiting the potentially insecticidal cysteine proteases from plants in the digestive tract. However, the biochemical identity of the cysteine protease inhibiting activity in midgut fluid has yet to be identified. PMID: 19729065 [PubMed - as supplied by publisher] (Source: Insect Biochemistry and Molecular Biology)
Source: Insect Biochemistry and Molecular Biology - August 30, 2009 Category: Biochemistry Authors: Li C, Song X, Li G, Wang P Tags: Insect Biochem Mol Biol Source Type: journals

Structural features conferring dual geranyl/farnesyl diphosphate synthase activity to an aphid prenyltransferase.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In addition to providing lipid chains for protein prenylation, short-chain isoprenyl diphosphate synthases (scIPPSs) play a pivotal role in the biosynthesis of numerous mevalonate pathway end-products, including insect juvenile hormone and terpenoid pheromones. For this reason, they are being considered as targets for pesticide development. Recently, we characterized an aphid scIPPS displaying dual geranyl diphosphate (GPP; C(10))/farnesyl diphosphate (FPP; C(15)) synthase activity in vitro. To identify the mechanism(s) responsible for this dual activity, we assessed the product selectivity of aphid scIPPSs bearing mut...
Source: Insect Biochemistry and Molecular Biology - August 27, 2009 Category: Biochemistry Authors: Vandermoten S, Santini S, Haubruge E, Heuze F, Francis F, Brasseur R, Cusson M, Charloteaux B Tags: Insect Biochem Mol Biol Source Type: journals

Functions of ion transport peptide and ion transport peptide-like in the red flour beetle Tribolium castaneum.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Ion transport peptide (ITP) and ITP-like (ITPL) are highly conserved neuropeptides in insects and crustaceans. We investigated the alternatively spliced variants of ITP/ITPL in Tribolium castaneum to understand their functions. We identified three alternatively spliced transcripts named itp, itpl-1, and itpl-2. Expression patterns of the splice variants investigated by exon-specific in situ hybridization were somewhat different from those previously reported in other insect species. Most importantly, we found for the first time that itpl-1 transcripts are abundantly expressed in the midgut at the late larval stage, sho...
Source: Insect Biochemistry and Molecular Biology - August 25, 2009 Category: Biochemistry Authors: Begum K, Li B, Beeman RW, Park Y Tags: Insect Biochem Mol Biol Source Type: journals

Structural model and functional characterization of the Bemisia tabaci CYP6CM1vQ, a cytochrome P450 associated with high levels of imidacloprid resistance.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, molecular docking and dynamic simulations were used to analyze interactions of imidacloprid with the biotype Q variant of the CYP6CM1 enzyme (CYP6CM1vQ). The binding mode with the lowest energy in the enzyme active site, the key amino acids involved (i.e. Phe-130 and Phe-226), and the putative hydroxylation site (lowest distance to carbon 5 of the imidazoline ring system of imidacloprid) were predicted. Heterologous expression of the CYP6CM1vQ confirmed the accuracy of our predictions and demonstrated that the enzyme catalyses the hydroxylation of imidacloprid to its less toxic 5-hydroxy form (K(cat) = 3.2 p...
Source: Insect Biochemistry and Molecular Biology - August 25, 2009 Category: Biochemistry Authors: Karunker I, Morou E, Nikou D, Nauen R, Sertchook R, Stevenson BJ, Paine MJ, Morin S, Vontas J Tags: Insect Biochem Mol Biol Source Type: journals

Identification and characterization of Aedes aegypti aminopeptidase N as a putative receptor of Bacillus thuringiensis Cry11A toxin.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, pull-down assays were performed using biotinylated Cry11Aa toxin and solubilized brush border membrane vesicles prepared from midguts of Aedes larvae. Three of the eluted proteins were identified as aminopeptidease N (APN), one of which was a 140 kDa protein, named AaeAPN1 (AAEL012778 in VectorBase). This protein localizes to the apical side of posterior midgut epithelial cells of larva. The full-length AaeAPN1 was cloned and expressed in Eschericia coli and in Sf21 cells. AaeAPN1 protein expressed in Sf21 cells was enzymatically active, had a GPI-anchor but did not bind Cry11Aa. A truncated AaeAPN1, however...
Source: Insect Biochemistry and Molecular Biology - August 18, 2009 Category: Biochemistry Authors: Chen J, Aimanova KG, Pan S, Gill SS Tags: Insect Biochem Mol Biol Source Type: journals

Studies on the black box: Incorporation of 3-oxo-7-dehydrocholesterol into ecdysteroids by Drosophila melanogaster and Manduca sexta.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
It has long been hypothesized that the oxidation of 7-dehydrocholesterol (7dC), made from dietary cholesterol (C), to 3-oxo-7dC (3-oxo-Delta(5,7)C) immediately precedes the unknown "Black Box" oxidations that lead to the formation of the first upstream intermediate exhibiting the highly characteristic ecdysteroid structure of the steroid molting hormone of insects, crustaceans and some other arthropods. Perhaps rate-limiting and under the control of the prothoracicotropic hormone (PTTH), the biosynthesis of 3-oxo-7dC and its subsequent oxidative modifications have been difficult to study because of their apparent insta...
Source: Insect Biochemistry and Molecular Biology - August 18, 2009 Category: Biochemistry Authors: Warren JT, O'Connor MB, Gilbert LI Tags: Insect Biochem Mol Biol Source Type: journals

Thermotolerance and gene expression following heat stress in the whitefly Bemisia tabaci B and Q biotypes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The whitefly Bemisia tabaci (Gennadius) causes tremendous losses to agriculture by direct feeding on plants and by vectoring several families of plant viruses. The B. tabaci species complex comprises over 10 genetic groups (biotypes) that are well defined by DNA markers and biological characteristics. B and Q are amongst the most dominant and damaging biotypes, differing considerably in fecundity, host range, insecticide resistance, virus vectoriality, and the symbiotic bacteria they harbor. We used a spotted B. tabaci cDNA microarray to compare the expression patterns of 6000 ESTs of B and Q biotypes under standard 25...
Source: Insect Biochemistry and Molecular Biology - August 12, 2009 Category: Biochemistry Authors: Mahadav A, Kontsedalov S, Czosnek H, Ghanim M Tags: Insect Biochem Mol Biol Source Type: journals

Differential gene expression in the mandibular glands of queen and worker honeybees, Apis mellifera L.: Implications for caste-selective aldehyde and fatty acid metabolism.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In honeybees, queens synthesize the "queen pheromone," whereas workers synthesize fatty acid components of "royal jelly" in their mandibular glands (MGs). To identify candidate proteins involved in the caste-selective MG function, we performed a proteomic analysis and identified three proteins that were expressed selectively in queen MGs (aldehyde dehydrogenase 1 [ALDH1], medium-chain acyl-CoA dehydrogenase [MCAD], and electron transfer flavoprotein alpha [ETFalpha)]), and a protein that was expressed selectively in worker MGs (fatty acid synthase [FAS)]). The quantitative reversed transcription-polymerase chain reacti...
Source: Insect Biochemistry and Molecular Biology - August 5, 2009 Category: Biochemistry Authors: Hasegawa M, Asanuma S, Fujiyuki T, Kiya T, Sasaki T, Endo D, Morioka M, Kubo T Tags: Insect Biochem Mol Biol Source Type: journals

Tick-derived Kunitz-type inhibitors as antihemostatic factors.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Endogenous Kunitz-type inhibitors target a large number of serine proteinases, including coagulation factors VIIa and Xa, but not thrombin. By contrast, several two-domain Kunitz inhibitors of this major procoagulant proteinase have been isolated from both soft ticks (e.g., ornithodorin from Ornithodoros moubata) and hard ticks (e.g., boophilin from Rhipicephalus (Boophilus) microplus). Surprisingly, these anticoagulants do not follow the canonical mechanism of proteinase inhibition. Instead, their N-terminal residues bind across the thrombin active-site cleft, while C-terminal modules interact with the basic exosite I...
Source: Insect Biochemistry and Molecular Biology - July 22, 2009 Category: Biochemistry Authors: Corral-Rodríguez MA, Macedo-Ribeiro S, Barbosa Pereira PJ, Fuentes-Prior P Tags: Insect Biochem Mol Biol Source Type: journals

Recombinant expression and biochemical characterization of the catalytic domain of acetylcholinesterase-1 from the African malaria mosquito, Anopheles gambiae.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Acetylcholinesterases (AChEs) and their genes from susceptible and resistant insects have been extensively studied to understand the molecular basis of target site insensitivity. Due to the existence of other resistance mechanisms, however, it can be problematic to correlate directly a mutation with the resistant phenotype. An alternative approach involves recombinant expression and characterization of highly purified wild-type and mutant AChEs, which serves as a reliable platform for studying structure-function relationships. We expressed the catalytic domain of Anopheles gambiae AChE1 (r-AgAChE1) using the baculoviru...
Source: Insect Biochemistry and Molecular Biology - July 12, 2009 Category: Biochemistry Authors: Jiang H, Liu S, Zhao P, Pope C Tags: Insect Biochem Mol Biol Source Type: journals

Identification and characterization of two arginine kinases from the parasitic insect Ctenocephalides felis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Arginine kinase (ATP:L-arginine omega-N-phosphotransferase, EC2.7.3.3.; AK) is an enzyme crucial for the energy metabolism of insects and other invertebrates, that has known allergenic potential in humans and that has been proposed as a pesticidal drug target. Here we report the identification, cDNA cloning, genomic gene structure and functional expression of AK genes from Ctenocephalides (C.) felis (cat flea). In contrast to other insect species investigated so far, C. felis possesses two AK genes, cfak1 and cfak2, encoding the functional enzymes CfAK1 and CfAK2 that can be distinguished by their guanidino substrate s...
Source: Insect Biochemistry and Molecular Biology - July 8, 2009 Category: Biochemistry Authors: Werr M, Cramer J, Ilg T Tags: Insect Biochem Mol Biol Source Type: journals

betaFTZ-F1 and Broad-Complex positively regulate the transcription of the wing cuticle protein gene, BMWCP5, in wing discs of Bombyx mori.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The present study was undertaken to clarify the mechanism regulating cuticle-protein gene expression. Expression of BMWCP5 was strong at around pupation and weak at the mid-pupal stage in wing tissues of B. mori. We analyzed the upstream region of the BMWCP5 gene using a transient reporter assay with a gene gun system to identify the regulatory elements responsible for its unique expression pattern. We identified two betaFTZ-F1 binding sites to be important cis-acting elements for the transcription activation of the luciferase reporter gene by an ecdysone pulse. Site-directed mutagenesis of these sites, followed by int...
Source: Insect Biochemistry and Molecular Biology - July 2, 2009 Category: Biochemistry Authors: Wang HB, Nitab M, Iwanaga M, Kawasaki H Tags: Insect Biochem Mol Biol Source Type: journals

Activation of BMWCP10 promoter and regulation by BR-C Z2 in wing disc of Bombyx mori.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The cuticle protein gene BMWCP10 is transcriptionally upregulated by ecdysone during development. In the present study, using a transient reporter assay, the activity of various genomic segments at the 5'-flanking region of the BMWCP10 gene in driving gene expression and their involvement in ecdysone-mediated activation were assessed in the Bombyx wing disc. The promoter activity of BMWCP10 was responsive to 20-hydroxyecdysone (20E) in a dose-dependent manner, and the highest luciferase activity was observed in the presence of 2 mug/ml 20E. Furthermore, the upstream BMWCP10 promoter was activated by 20E in a stage-spec...
Source: Insect Biochemistry and Molecular Biology - July 2, 2009 Category: Biochemistry Authors: Wang HB, Iwanaga M, Kawasaki H Tags: Insect Biochem Mol Biol Source Type: journals

Characterization of endogenous and recombinant forms of laccase-2, a multicopper oxidase from the tobacco hornworm, Manduca sexta.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Laccases belong to the group of multicopper oxidases that exhibit wide substrate specificity for polyphenols and aromatic amines. They are found in plants, fungi, bacteria, and insects. In insects the only known role for laccase is in cuticle sclerotization. However, extracting laccase from the insect's cuticle requires proteolysis, resulting in an enzyme that is missing its amino-terminus. To circumvent this problem, we expressed and purified full-length and amino-terminally truncated recombinant forms of laccase-2 from the tobacco hornworm, Manduca sexta. We also purified the endogenous enzyme from the pharate pupal ...
Source: Insect Biochemistry and Molecular Biology - June 30, 2009 Category: Biochemistry Authors: Dittmer NT, Gorman MJ, Kanost MR Tags: Insect Biochem Mol Biol Source Type: journals

An insight into the transcriptome and proteome of the salivary gland of the stable fly, Stomoxys calcitrans.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Adult stable flies are blood feeders, a nuisance, and mechanical vectors of veterinary diseases. To enable efficient feeding, blood sucking insects have evolved a sophisticated array of salivary compounds to disarm their host's hemostasis and inflammatory reaction. While the sialomes of several blood sucking Nematocera flies have been described, no thorough description has been made so far of any Brachycera, except for a detailed proteome analysis of a tabanid (Xu et al., 2008). In this work we provide an insight into the sialome of the muscid Stomoxys calcitrans, revealing a complex mixture of serine proteases, endonu...
Source: Insect Biochemistry and Molecular Biology - June 30, 2009 Category: Biochemistry Authors: Wang X, Ribeiro JM, Broce AB, Wilkerson MJ, Kanost MR Tags: Insect Biochem Mol Biol Source Type: journals

Purification of an active, oligomeric chitin synthase complex from the midgut of the tobacco hornworm.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Chitin formation depends on the activity of a family II glycosyltransferase known as chitin synthase, whose biochemical and structural properties are largely unknown. Previously, we have demonstrated that the chitin portion of the peritrophic matrix in the midgut of the tobacco hornworm, Manduca sexta, is produced by chitin synthase 2 (CHS-2), one of two isoenzymes encoded by the Chs-1 and Chs-2 genes (also named Chs-A and Chs-B), and that CHS-2 is located at the apical tips of the brush border microvilli. Here we report the purification of the chitin synthase from the Manduca midgut as monitored by its activity and im...
Source: Insect Biochemistry and Molecular Biology - June 30, 2009 Category: Biochemistry Authors: Maue L, Meissner D, Merzendorfer H Tags: Insect Biochem Mol Biol Source Type: journals

The insect SNMP gene family.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present indirect evidence based on evolutionary selection (dN/dS) that the dipteran SNMPs are expressed as functional proteins. We observed expansions of the SNMP1 sub-clade in C. pipiens q. and T. castaneum suggesting that the SNMP1s may have an expanded functional role in these species. PMID: 19364529 [PubMed - in process] (Source: Insect Biochemistry and Molecular Biology)
Source: Insect Biochemistry and Molecular Biology - June 28, 2009 Category: Biochemistry Authors: Vogt RG, Miller NE, Litvack R, Fandino RA, Sparks J, Staples J, Friedman R, Dickens JC Tags: Insect Biochem Mol Biol Source Type: journals

A lepidopteran pacifastin member: cloning, gene structure, recombinant production, transcript profiling and in vitro activity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Members of the pacifastin family have been characterized as serine peptidase inhibitors (PI), but their target enzyme(s) are unknown in insects. So far, the structural and biochemical characteristics of pacifastin-like PI have only been studied in locusts. Here we report the molecular identification and functional characterization of a pacifastin-like precursor in a lepidopteran insect, i.e. the silkworm Bombyx mori. The bmpp-1 gene contains 17 exons and codes for two pacifastin-related precursors of different length. The longest splice variant encodes 13 inhibitor domains, more than any other pacifastin-like precursor...
Source: Insect Biochemistry and Molecular Biology - June 28, 2009 Category: Biochemistry Authors: Breugelmans B, Simonet G, van Hoef V, Van Soest S, Smagghe G, Vanden Broeck J Tags: Insect Biochem Mol Biol Source Type: journals

Binding specificity of locust odorant binding protein and its key binding site for initial recognition of alcohols.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Odorant binding proteins (OBPs) are required for olfaction perception, and thus may be possible targets for controlling the population of pests by interfering with their chemical communication. A single OBP LmigOBP1 has been identified in the antennae of Locusta migratoria, though four isoforms have been detected. Here, we have investigated the ligand-binding specificity of LmigOBP1 using 67 volatile odor compounds. Fluorescence assays indicate that LmigOBP1 does not bind fecal volatiles or green leaf odors, but shows high affinity for some linear aliphatic compounds, with pentadecanol and 2-pentadecanone being the str...
Source: Insect Biochemistry and Molecular Biology - June 28, 2009 Category: Biochemistry Authors: Jiang QY, Wang WX, Zhang Z, Zhang L Tags: Insect Biochem Mol Biol Source Type: journals

Mutation of an aminopeptidase N gene is associated with Helicoverpa armigera resistance to Bacillus thuringiensis Cry1Ac toxin.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A Cry1Ac-resistant strain (Bt-R) of Helicoverpa armigera, with 2971-fold resistance, was derived by selection with Cry1Ac toxin for 75 generations. We used cDNA-amplified fragment length polymorphism analysis to identify those genes differentially expressed in the Cry1Ac-resistant and -susceptible strains, which revealed 212 differentially expressed transcripts among 2000 screened cDNAs. Among these transcript-derived fragments (TDFs), 37 showed some homology to known sequences, including Aminopeptidase N (APN), which is expressed in the midgut epithelium and has been implicated as a Cry1A subfamily receptor in several...
Source: Insect Biochemistry and Molecular Biology - June 28, 2009 Category: Biochemistry Authors: Zhang S, Cheng H, Gao Y, Wang G, Liang G, Wu K Tags: Insect Biochem Mol Biol Source Type: journals

Global transcriptional analysis of pheromone biosynthesis-related genes in the female turnip moth, Agrotis segetum (Noctuidae) using a custom-made cDNA microarray.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Using a custom-made cDNA microarray, global transcriptional analyses were conducted to identify genes differentially regulated in the pheromone gland as compared to the remaining insect tissue of the moth Agrotis segetum (Noctuidae). A two-fold or larger difference in relative expression levels was found for 227 of 864 genes investigated comparing the two tissues. Unexpectedly, an antennal binding protein homologue, containing a pheromone-binding/general odorant-binding protein PFAM domain, was expressed at a 56-fold higher level in the pheromone gland. Relatively higher expression levels in the pheromone gland were al...
Source: Insect Biochemistry and Molecular Biology - June 28, 2009 Category: Biochemistry Authors: Strandh M, Johansson T, Löfstedt C Tags: Insect Biochem Mol Biol Source Type: journals

A phosphoproteomics approach to elucidate neuropeptide signal transduction controlling insect metamorphosis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we used quantitative phosphoproteomics to investigate signal transduction events initiated by PTTH. We identified Spook (CYP307A1), a suspected rate-limiting enzyme for E biosynthesis, and components of the mitogen-activated protein kinase (MAPK) pathway, as major phosphorylation targets of PTTH signaling. Further, proteins not previously linked to PTTH and ecdysone biosynthesis were identified as targets of PTTH signaling. These include proteins involved in signal transduction, endosomal trafficking, constituents of the cytoskeleton and regulators of transcription and translation. Our screen shows that PTTH...
Source: Insect Biochemistry and Molecular Biology - June 28, 2009 Category: Biochemistry Authors: Rewitz KF, Larsen MR, Lobner-Olesen A, Rybczynski R, O'Connor MB, Gilbert LI Tags: Insect Biochem Mol Biol Source Type: journals

The Anopheles gambiae salivary protein gSG6: an anopheline-specific protein with a blood-feeding role.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report here the expression of a recombinant form of the protein and we show that in vivo gSG6 is expressed in distal-lateral lobes and is secreted with the saliva while the female mosquito probes for feeding. Injection of gSG6 dsRNA into adult A. gambiae females results in decreased gSG6 protein levels, increased probing time and reduced blood feeding ability. gSG6 orthologs have been found so far only in the salivary glands of Anopheles stephensi and Anopheles funestus, both members of the Cellia subgenus. We report here the gSG6 sequence from five additional anophelines, four species of the A. gambiae complex and Anop...
Source: Insect Biochemistry and Molecular Biology - June 28, 2009 Category: Biochemistry Authors: Lombardo F, Ronca R, Rizzo C, Mestres-Simòn M, Lanfrancotti A, Currà C, Fiorentino G, Bourgouin C, Ribeiro JM, Petrarca V, Ponzi M, Coluzzi M, Arcà B Tags: Insect Biochem Mol Biol Source Type: journals

Chromatographic and electrophoretic resolution of proteins and protein complexes from the larval midgut microvilli of Manduca sexta.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The microvillar proteome of Manduca sexta larval midguts was analyzed by subjecting brush border membrane vesicles (BBMV) to two different two-dimensional approaches: (i) Anion exchange chromatography followed by SDS-PAGE and (ii) Blue Native-PAGE followed by SDS-PAGE. The first technique was superior to conventional 2-D gel electrophoresis in resolving the most abundant proteins associated with the midgut microvilli. Twenty of them were successfully identified as digestive enzymes, binding targets of the insecticidal Cry1A toxins from Bacillus thuringiensis (Bt), and signal transduction proteins. A homolog of the chlo...
Source: Insect Biochemistry and Molecular Biology - June 28, 2009 Category: Biochemistry Authors: Pauchet Y, Muck A, Svatos A, Heckel DG Tags: Insect Biochem Mol Biol Source Type: journals

Towards Coleoptera-specific high-throughput screening systems for compounds with ecdysone activity: development of EcR reporter assays using weevil (Anthonomus grandis)-derived cell lines and in silico analysis of ligand binding to A. grandis EcR ligand-binding pocket.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report here the development and evaluation of two coleopteran-specific reporter-based screening systems to discover and evaluate ecdysone agonists. The screening systems are based on the cell lines BRL-AG-3A and BRL-AG-3C that are derived from the weevil Anthonomus grandis, which can be efficiently transduced with an EcR reporter cassette for evaluation of induction of reporter activity by ecdysone agonists. We also cloned the almost full length coding sequence of EcR expressed in the cell line BRL-AG-3C and used it to make an initial in silico 3D model of its ligand-binding pocket docked with ponasterone A and tebufeno...
Source: Insect Biochemistry and Molecular Biology - June 18, 2009 Category: Biochemistry Authors: Soin T, Iga M, Swevers L, Rougé P, Janssen CR, Smagghe G Tags: Insect Biochem Mol Biol Source Type: journals

Comparative and functional genomics of lipases in holometabolous insects.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Lipases have key roles in insect lipid acquisition, storage and mobilisation and are also fundamental to many physiological processes underpinning insect reproduction, development, defence from pathogens and oxidative stress, and pheromone signalling. We have screened the recently sequenced genomes of five species from four orders of holometabolous insects, the dipterans Drosophila melanogaster and Anopheles gambiae, the hymenopteran Apis mellifera, the moth Bombyx mori and the beetle Tribolium castaneum, for the six major lipase families that are also found in other organisms. The two most numerous families in the ins...
Source: Insect Biochemistry and Molecular Biology - June 16, 2009 Category: Biochemistry Authors: Horne I, Haritos VS, Oakeshott JG Tags: Insect Biochem Mol Biol Source Type: journals

Peptidomic survey of the locust neuroendocrine system.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Neuropeptides are important controlling agents in animal physiology. In order to understand their role and the ways in which neuropeptides behave and interact with one another, information on their time and sites of expression is required. We here used a combination of MALDI-TOF and ESI-Q-TOF mass spectrometry to make an inventory of the peptidome of different parts (ganglia and nerves) of the central nervous system from the desert locust Schistocerca gregaria and the African migratory locust Locusta migratoria. This way, we analysed the brain, suboesophageal ganglion, retrocerebral complex, stomatogastric nervous syst...
Source: Insect Biochemistry and Molecular Biology - June 11, 2009 Category: Biochemistry Authors: Clynen E, Schoofs L Tags: Insect Biochem Mol Biol Source Type: journals

The beta2-tubulin gene from three tephritid fruit fly species and use of its promoter for sperm marking.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
To isolate testis-specific regulatory DNA that could be used in genetically transformed insect pest species to improve their biological control, beta2-tubulin genes and their proximal genomic DNA were isolated from three economically important tephritid pest species, Anastrepha suspensa, Anastrepha ludens, and Bactrocera dorsalis. Gene isolation was first attempted by degenerate PCR on an A. suspensa adult male testes cDNA library, which fortuitously isolated the 2.85 kb beta1-tubulin gene that encodes a 447 amino acid polypeptide. Subsequent PCR using 5' and 3' RACE generated the 1.4 kb Asbeta2-tubulin gene that encod...
Source: Insect Biochemistry and Molecular Biology - June 8, 2009 Category: Biochemistry Authors: Zimowska GJ, Nirmala X, Handler AM Tags: Insect Biochem Mol Biol Source Type: journals

QTL analysis of sex pheromone blend differences between two closely related moths: Insights into divergence in biosynthetic pathways.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study confirms previously discovered QTL, but also reports new QTL. Most importantly, we found relatively large QTL affecting Z9-16:Ald, the critical sex pheromone component of Hs. For Z9-14:Ald, the critical sex pheromone component of Hv, as well as for the minor pheromone compound 14:Ald, we found QTL in which the change in pheromone ratio was opposite-to-expected. Linking QTL to the biosynthetic pathways of the pheromone compounds of Hv and Hs implicates several candidate genes in the divergence of these premating signals, the most important of which are acetyl transferase, one or more desaturase(s), and a fatty ac...
Source: Insect Biochemistry and Molecular Biology - May 26, 2009 Category: Biochemistry Authors: Groot AT, Estock ML, Horovitz JL, Hamilton J, Santangelo RG, Schal C, Gould F Tags: Insect Biochem Mol Biol Source Type: journals

Cathepsin L-like cysteine proteinase (DcCathL) from Delia coarctata (wheat bulb fly): Basis of insecticidal activity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A cDNA encoding a cathepsin L-like cysteine proteinase (DcCathL) was prepared from gut tissue of larvae of wheat bulb fly (Delia coarctata: Diptera). The predicted protein is a homologue of the product of Drosophila melanogaster gene Cp-1 (CG6692), and is similar to a sub-family of cysteine proteinases found in other insects which have roles in tissue remodelling during development, and moulting. Recombinant DcCathL was produced using the yeast Pichia pastoris as expression host, and showed hydrolytic activity in vitro towards the synthetic substrate Z-Phe-Arg-AMC with a pH optimum of 4.5. DcCathL was insecticidal to l...
Source: Insect Biochemistry and Molecular Biology - May 26, 2009 Category: Biochemistry Authors: Pyati PS, Bell HA, Fitches E, Price DR, Gatehouse AM, Gatehouse JA Tags: Insect Biochem Mol Biol Source Type: journals