Search results for "Juvenile Hormone"

A novel putative insect chitinase with multiple catalytic domains: hormonal regulation during metamorphosis

2002

0264-6021 (Print) Journal Article Research Support, Non-U.S. Gov't; We have used differential display to identify genes that are regulated by juvenile hormone in the epidermis of the beetle Tenebrio molitor. One of the genes encodes T. molitor chitinase 5 (TmChit5), a chitinase possessing an unusual structure. Sequence analysis of TmChit5 identified five 'chitinase units' of approx. 480 amino acids with similarity to chitinase family 18. These units are separated by less conserved regions containing putative PEST (rich in proline, glutamic acid, serine and threonine) sequences, putative chitin-binding domains and mucin domains. Northern-blot analysis identified a single transcript of approx…

Pilot study on the combination of an organophosphate-based insecticide paint and pyrethroid-treated long lasting nets against pyrethroid resistant ma…

2015

International audience; A pilot study to test the efficacy of combining an organophosphate-based insecticide paint and pyrethroid-treated Long Lasting Insecticide Treated Nets (LLINs) against pyrethroid-resistant malaria vector mosquitoes was performed in a real village setting in Burkina Faso. Paint Inesfly 5A IGR™, comprised of two organophosphates (OPs) and an Insect Growth Regulator (IGR), was tested in combination with pyrethroid-treated LLINs. Efficacy was assessed in terms of mortality for 12 months using Early Morning Collections of malaria vectors and 30-minute WHO bioassays. Resistance to pyrethroids and OPs was assessed by detecting the frequency of L1014F and L1014S kdr mutation…

Hormonal regulation of JP29 in the epidermis during Larval development and metamorphosis in the Tobacco Hornworm, Manduca sexta

1997

Cuticular protein genes in Tenebrio molitor (Coleoptera: Tenebrionidae)

1995

1210-5759; We have previously isolated from the beetle Tenebrio molitor, cDNAs coding for two glycine-rich cuticular proteins named ACP-20, ACP-22 and ACP-17 and an alanin-rich cuticular protein named LPCP-22. The ACP-20, ACP-22, ACP-17 mRNAs are detected by Northern blot and In situ hybridization analysis only in epidermal regions secreting heavily sclerotized cuticle during the pharate adult stage.The LPCP-22 mRNA is detected in most epidermal regions during the secretion of larval and pupal cuticles. Then, its presence is restricted to the epidermal zones secreting intersegmental soft cuticle in the newly ecdysed pupa. The stage- and tissue-specific gene system seems to be convenient mod…

Glycosidic juvenogens: derivatives bearing alpha,beta-unsaturated ester functionalities.

2007

Abstract A series of the protected alkyl glycosides 5a / 5b – 12a / 12b was synthesized from the parent isomeric alcohols (insect juvenile hormone bioanalogs; juvenoids), 4-[4′-(2″-hydroxycyclohexyl)methylphenoxy]-3-methyl-but-2-enoic acid ethyl ester ( 1a / 1b – 4a / 4b ; racemic structures) and ( 1a – 4a ; enantiopure structures). Cadmium carbonate was used as a promoter of this Koenigs–Knorr reaction, and the products were obtained in 82–92% yields. Deprotection of the carbohydrate functionality of 5a / 5b – 12a / 12b was carefully performed using ethanolysis in the presence of zinc acetate, due to the presence of another ester functionality in the aglycone part of the molecule of protec…

The role of juvenile hormone in immune function and pheromone production trade-offs: a test of the immunocompetence handicap principle

2003

The immunocompetence handicap hypothesis postulates that secondary sexual traits are honest signals of mate quality because the hormones (e.g. testosterone) needed to develop secondary sexual traits have immunosuppressive effects. The best support for predictions arising from the immunocompetence handicap hypothesis so far comes from studies of insects, although they lack male-specific hormones such as testosterone. In our previous studies, we found that female mealworm beetles prefer pheromones of immunocompetent males. Here, we tested how juvenile hormone (JH) affects male investment in secondary sexual characteristics and immune functions in the mealworm beetle, Tenebrio molitor. We inje…

A nuclear juvenile hormone-binding protein from larvae of Manduca sexta: a putative receptor for the metamorphic action of juvenile hormone

1994

0027-8424 (Print) Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S.; A 29-kDa nuclear juvenile hormone (JH)-binding protein from the epidermis of Manduca sexta larvae was purified by using the photoaffinity analog for JH II ([3H]epoxyhomofarnesyldiazoacetate) and partially sequenced. A 1.1-kb cDNA was isolated by using degenerate oligonucleotide primers for PCR based on these sequences. The cDNA encoded a 262-amino acid protein that showed no similarity with other known proteins, except for short stretches of the interphotoreceptor retinoid-binding protein, rhodopsin, and human nuclear protein p68. Recombinant bacu…

Matters of scale: positive allometry and the evolution of male dimorphisms

2005

J.L.T. was funded by a Biotechnology and Biological Sciences Research Council research fellowship, J.S.K. by the Academy of Finland, and N.R.L. by a Natural Environment Research Council research fellowship. The developmental independence of alternative phenotypes is key to evolutionary theories of phenotypic plasticity and the origins of diversity. Male dimorphisms associated with alternative reproductive tactics are widely cited examples of such facultative expression of divergent fitness optima. Current models for the evolution of male dimorphisms invoke a size-dependent threshold at which the phenotype is reprogrammed. We use predictions derived from allometric modeling to test for the e…

Electron microscopic study on the larval and adult corpus allatum of Oncopeltus fasciatus dallas (insecta, heteroptera)

1973

1. The ultrastructure of the corpora allata of last larval instars and adults of Oncopeltus was studied. The unpaired gland undergoes submicroscopic alterations and shows signs of degradation in old animals. The organ is partly covered and penetrated by corpus cardiacum tissue. Axons with different types of neurosecretory granules form synaptoid contacts with the corpus allatum cells.

Purification and reassessment of ligand binding by the recombinant, putative juvenile hormone receptor of the tobacco hornworm, Manduca sexta

1996

The 29 kDa protein from the larval epidermis of the tobacco hornworm, Manduca sexta, that specifically bound photoaffinity analogs of JH I and JH II was produced by a recombinant baculovirus (rJP29). The higher of the two molecular weight forms made corresponded to a protein that could be formed by read‐through of the TGA termination codon to the following TAA. The previously reported, apparent high affinity binding of [methyl‐3H]‐JH I by rJP29 as measured by the dextran‐coated charcoal (DCC) assay [Palli et al., Proc Natl Acad Sci USA 91:6191–6195 (1994)] was found to be artifactual due to endogenous cellular esterases that co‐purified with rJP29 through both DEAE cellulose and MonoQ chrom…