Search results for "Juvenile hormone"
showing 10 items of 50 documents
A monoclonal antibody against an adult-specific cuticular protein of Tenebrio molitor (Insecta, Coleoptera)
1989
International audience; To study the sequential expression of the epidermal program in the mealworm Tenebrio molitor, monoclonal antibodies were prepared against the water-soluble proteins from preecdysial adult cuticle. Among the 16 clones obtained, one of them (named K2F6) recognized a 20-kDa antigen, found only in adult extracts but not in the larval or pupal ones, as revealed by immunoblot analysis. Our results strongly suggest an epidermal origin for this protein. The monoclonal antibody K2F6 fails to react with water-soluble proteins from fat body and hemolymph taken during the deposition of the 20-kDa antigen. Electron microscopic immunogold localization of this antigen showed that i…
Ecdysteroid-dependent larval-adult oviduct transformation in the milkweed bugOncopeltus fasciatus requires absence of juvenile hormone
1987
It has been tested whether juvenile hormone plays a role in the larval-adult transformation of lateral oviducts in the milkweed bug. The transformation is ecdysteroid-dependent, as was reported previously2. Application of precocene or juvenile hormone III proved that the absence of juvenile hormone is required.
Candidate target mechanisms of the growth inhibitor cyromazine: Studies of phenylalanine hydroxylase, puparial amino acids, and dihydrofolate reducta…
2000
Cyromazine, an insect growth regulator, affects larval and pupal cuticles in dipterans and some other insects. The mode of action of this aminotriazine is not known yet, though it has been shown not to inhibit the synthesis of chitin and cuticular proteins. Cyromazine may, however, act on some step(s) of sclerotization of the cuticle. In the present study, we have analyzed the key enzyme for the production of sclerotization agents, phenylalanine hydroxylase (PAH), using the enzyme from Drosophila, a cyromazine-sensitive insect. PAH was studied in vitro with cyromazine and three biologically less active derivatives at concentrations ranging from 1 μM to 1 mM. None of the compounds did signif…
Pre-invasion history and demography shape the genetic variation in the insecticide resistance-related acetylcholinesterase 2 gene in the invasive Col…
2012
Abstract Background Invasive pest species offers a unique opportunity to study the effects of genetic architecture, demography and selection on patterns of genetic variability. Invasive Colorado potato beetle (Leptinotarsa decemlineata) populations have experienced a rapid range expansion and intense selection by insecticides. By comparing native and invasive beetle populations, we studied the origins of organophosphate (OP) resistance-associated mutations in the acetylcholinesterase 2 (AChE2) gene, and the role of selection and demography on its genetic variability. Results Analysis of three Mexican, two US and five European populations yielded a total of 49 haplotypes. Contrary to the exp…
Characterization of a putative extracellular matrix protein from the beetle Tenebrio molitor: hormonal regulation during metamorphosis.
2004
0949-944X (Print) Journal Article Research Support, Non-U.S. Gov't; We used differential display to isolate epidermis cDNAs corresponding to juvenile-hormone analog-regulated mRNA from the beetle Tenebrio molitor. One of them encodes a putative extracellular matrix (ECM) protein, named Tenebrin. Indeed, the deduced protein sequence contains ECM typical features like the presence of a signal peptide, internal repeats, a RGD tripeptide sequence motif known to bind integrins and von Willebrand factor type c domains involved in protein-protein interactions. Northern blot analysis reveals a single transcript of about 11 kb with an expression pattern correlated to 20-hydroxyecdysone fluctuations …
Characterization of a cDNA clone encoding a glycine-rich cuticular protein of Tenebrio molitor: developmental expression and effect of a juvenile hor…
1992
0962-1075 (Print) Journal Article; The complete sequence of a cDNA clone, isolated from epidermal mRNA of Tenebrio molitor using a monoclonal antibody raised against an adult-specific cuticular antigen only present in the hard cuticle, was obtained after primer extension at the 5' end. From this cDNA sequence, the deduced protein encompasses 199 amino acids (including a signal peptide) with a total molecular weight of 20.7 kDa. The protein exhibits a bipartite structure: glycine-rich region located in its NH2-terminal part and a carboxy-terminal domain sharing homologies with other cuticular proteins of Orthoptera, Diptera and Lepidoptera. In-situ hybridization analysis shows that the corre…
Analysis of involvement of the 3?-untranslated regions in regulating mRNA stability for vitellogenin, cyanoprotein ?, and cyanoprotein ? from the bea…
2002
The degradation of the 3'-untranslated regions (UTRs) of vitellogenin, cyanoprotein alpha, and cyanoprotein beta from the bean bug, Riptortus clavatus, was analyzed in vitro. The degradation pattern was similar for all three RNAs, with a high degradation rate in non-diapausing adult insects and no degradation in the fifth instar nymphs and in diapausing adults, and was not correlated with the expression levels of these three proteins. Proteins binding to the 3'-UTRs were detected in polysomal and cytosolic extracts. These factors, however, were present in all developmental stages. The abundance of the polysomal factor showed little variation, but the cytosolic factor was enriched in adult i…
Ligand-binding properties of the juvenile hormone receptor, Methoprene-tolerant
2012
Ligand-binding properties of the juvenile hormone receptor, Methoprene-tolerant. 53. annual drosophila research conference
Monoclonal antibodies recognizing larval- and pupal-specific cuticular proteins of Tenebrio molitor (Insecta, Coleoptera)
1993
To study the sequential expression of insect epidermal cells during metamorphosis, a library of monoclonal antibodies (MABs) was prepared against the water-soluble proteins from preecdysial pupal cuticle of Tenebrio molitor. Six selected MABs recognizing only larval and pupal cuticular proteins (CPs) in immunoblot analysis were classified into three types. Type 1 recognized a 21.5 and a 22 kDa polypeptide, type 2, a 26 kDa polypeptide, and type 3, three polypeptides of 18.5, 19.5 and 21.5 kDa. They did not immunoreact with any protein of fat bodies or haemolymph from pharate pupae, suggesting that the antigens originate from the epidermis. The stage-specificity was confirmed by electron mic…
Development of the wing discs of Zophobas atratus under natural and experimental conditions: occurrence of a gradual larval-pupal commitment in the e…
1999
Using light and electron microscopy, we studied the development of the wing discs in the large beetle Zophobas atratus, under natural and experimental conditions. A reversible differentiation of the wing discs is usually observed during supernumerary instars of crowded larvae. Juvenile hormone analog (JHA) application during the wandering period or compelled experimental crowding during the larval-pupal switchover – or commitment – inhibits the onset of metamorphosis. Isolation, followed by recrowding, also induces the disc cells to secrete unusual cuticular material. Recrowding is able to trigger the reversal of metamorphosis during the 4-day period when larval-pupal commitment is taking p…