Alkaline phosphatases and aminopeptidases are altered in a Cry11Aa resistant strain of Aedes aegypti.

Bacillus thuringiensis subsp. israelensis (Bti) is widely used for the biological control of mosquito populations. However, the mechanism of Bti toxins is still not fully understood.

Aedes cadherin mediates the in vivo toxicity of the Cry11Aa toxin to Aedes aegypti.

Cadherin plays an important role in the toxicity of Bacillus thuringiensis Cry proteins. We previously cloned a full-length cadherin from Aedes aegypti larvae and reported this protein binds Cry11Aa toxin from B. thuringiensis subsp.

Characterization of a blood-meal-responsive proton-dependent amino acid transporter in the disease vector, Aedes aegypti.

After anautogenous mosquitoes ingest the required blood meal, proteins in it are rapidly cleaved, yielding a large pool of amino acids. Transport of these amino acids into gut epithelial cells and their subsequent translocation into other tissues is critical for oogenesis and other physiological processes. We have identified a proton amino acid transporter (PAT) in Aedes aegypti (AaePAT1, AAEL007191) which facilitates this transport and is expressed in epithelial cell membranes of larval caecae and the adult midgut.

Aedes aegypti cadherin serves as a putative receptor of the Cry11Aa toxin from Bacillus thuringiensis subsp. israelensis.

Cry11Aa of Bacillus thuringiensis subsp. israelensis is the most active toxin to Aedes aegypti in this strain. We previously reported that, in addition to a 65 kDa GPI (glycosylphosphatidylinositol)-anchored ALP (alkaline phosphatase), the toxin also binds a 250 kDa membrane protein.

Loop residues of the receptor binding domain of Bacillus thuringiensis Cry11Ba toxin are important for mosquitocidal activity.

Using a Cry11Ba toxin model, predicted loops in domain II were analyzed for their role in receptor binding and toxicity. Peptides corresponding to loops alpha8, 1 and 3, but not loop 2, competed with toxin binding to Aedes midgut membranes. Mutagenesis data reveal loops alpha8, 1 and 3 are involved in toxicity.

The pheromone biosynthesis activating neuropeptide (PBAN) receptor of Heliothis virescens: identification, functional expression, and structure-activity relationships of ligand analogs.

Pheromone biosynthesis activating neuropeptide (PBAN) promotes synthesis and release of sex pheromones in moths. We have identified and functionally expressed a PBAN receptor from Heliothis virescens (HevPBANR) and elucidated structure-activity relationships of PBAN analogs. Screening of a larval CNS cDNA library revealed three putative receptor subtypes and nucleotide sequence comparisons suggest that they are produced through alternative splicing at the 3'-end.

NHE8 mediates amiloride-sensitive Na+/H+ exchange across mosquito Malpighian tubules and catalyzes Na+ and K+ transport in reconstituted proteoliposomes.

Following a blood meal, the mosquito Aedes aegypti will have acquired an enormous sodium load that must be rapidly excreted to restore ion homeostasis. It is a process that demands robust sodium and fluid transport capabilities. Even though the identities of the components involved in this ion transport across the mosquito Malpighian tubule epithelia have not been completely determined, electrophysiological studies suggest the contribution of a Na(+)/H(+) exchanger extruding cations into the lumen driven secondarily by the proton gradient created by the V-type H(+)-ATPase in the tubules' apical membrane.

P-type Na+/K+-ATPase and V-type H+-ATPase expression patterns in the osmoregulatory organs of larval and adult mosquito Aedes aegypti.

This study describes the expression patterns of P-type Na(+)/K(+)-ATPase and V-type H(+)-ATPase in the larval and adult forms of the mosquito Aedes aegypti and provides insight into their relative importance in ion transport function of key osmoregulatory organs. RT-PCR assays indicate that, at the level of the gene, both ATPases are expressed in all of the osmoregulatory tissues of larvae (midgut, Malpighian tubules, rectum and anal papillae) and adults (stomach, Malpighian tubules, anterior hindgut and rectum). Immunohistochemical studies determined that both ATPases are present in high levels in all the relevant organs, with the exception of the larval rectum (P-type Na(+)/K(+)-ATPase only).

Molecular characterization of sodium/proton exchanger 3 (NHE3) from the yellow fever vector, Aedes aegypti.

Transport across insect epithelia is thought to depend on the activity of a vacuolar-type proton ATPase (V-ATPase) that energizes ion transport through a secondary proton/cation exchanger. Although several of the subunits of the V-ATPase have been cloned, the molecular identity of the exchanger has not been elucidated. Here, we present the identification of sodium/proton exchanger isoform 3 (NHE3) from yellow fever mosquito, Aedes aegypti (AeNHE3).

Expression of Cry1Ac cadherin receptors in insect midgut and cell lines.

Cadherin-like proteins have been identified as putative receptors for the Bacillus thuringiensis Cry1A proteins in Heliothis virescens and Manduca sexta. Immunohistochemistry showed the cadherin-like proteins are present in the insect midgut apical membrane, which is the target site of Cry toxins. This subcellular localization is distinct from that of classical cadherins, which are usually present in cell-cell junctions.

Identification, functional characterization and expression of a LAT type amino acid transporter from the mosquito Aedes aegypti.

We isolated two cDNAs from the mosquito Aedes aegypti, an L-amino acid transporter (AeaLAT) and a CD98 heavy chain (AeaCD98hc). Expression of AeaCD98hc or AeaLAT alone in Xenopus oocyte did not induce amino acid transport activity. However, co-expression of AeaCD98hc and AeaLAT, which are postulated to form a heterodimer protein linked through a disulfide bond, showed significant increase in amino acid transport activity.