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Binding of Aedes aegypti trypsin modulating oostatic factor [Aea-TMOF] to its receptor stimulates phosphorylation and protease processing of gut-membrane proteins

100%

Borovsky D., Hamdaoui A.

Pestycydy

2008

nr 1-2

13-25

The binding of TMOF to its gut receptor was followed by incubating guts removed from male and female Aedes aegypti. TMOF at physiological concentrations, in the presence of [γ32P]ATP, causes phosphorylation and release of gut-membrane protein (45 kDa) that is further processed by proteolysis. In the presence of protease inhibitors only the 45 kDa protein was released. The phosphorylation and processing of the 45 kDa protein does not happen in the absence of TMOF. Both larvae and adult guts release the protein in the presence of TMOF. Male Ae. aegypti do not synthesize trypsin in their gut and do not release the 45 kDa protein in the presence of TMOF because a TMOF receptor is probably absent. Homogenized guts do not release the 45 kDa protein, indicating that the protease processing or the ecto-protein kinase activity is probably reduced after breaking the tissue. The 45 kDa phosphorylated protein can be dephosphorylated by alkaline phosphatase and protein phosphatase, indicating that the phosphate group is covalently linked to either a serine or a tyrosine moiety. This is the first report that shows that in insects, binding of a peptide hormone activates its receptor by proteolysis.

Control of Aedes aegypti larvae with Aea-TMOF mimics: aromatic derivatives of enoic acid

100%

Borovsky D.

Pestycydy

2008

nr 1-2

27-34

Based on the 3D conformation of the N-terminus of TMOF in solution, six aromatic derivatives of enoic acid: 7-biphenyl-4-yl-hept-4-enoic acid (BPHE), 7-(4-butyl-phenyl)-hept-4-enoic acid (BuPHE), 7-cyclohexyl-hept-4-enoic acid (CyHE), 10-phenyl-dec-7-enoic acid (PDE), 7-p-tolyl-hept-2-enoic acid ethyl ester (THEEE) and 7-(4-methoxy-phenyl)-hept-2-enoic acid ethyl ester (MPEEE) were computer-modeled and synthesized. Treating first instar Aedes aegypti larvae with different concentrations of the TMOF mimics showed that addition of butyl to the benzyl ring, use of p-tolyl or converting the benzyl ring into cyclohexane increased the biological activity of the mimics by 5.2, 5.0 and 3.8-fold, respectively. Esterifying the carboxyl terminus into ethyl ester and addition of a methoxy group to the benzyl ring also increased, by 2-fold, the biological activity of the derivative. The position of the double bond in the aliphatic chain is important for enhanced biological activity. Aea-TMOF and CyHE fed to mosquito larvae equally inhibited trypsin biosynthesis in larvae for the first 24 h. The biological activity of CyHE, however, rapidly declined 2-3 days later, whereas TMOF activity stayed stable. These results indicate that TMOF organic mimics, although potent, need to be formulated in order to be more stable for future field applications.

Ograniczanie wyników

2 Pestycydy

2 Borovsky D.

1 Hamdaoui A.

2 2008

Wyniki wyszukiwania

Binding of Aedes aegypti trypsin modulating oostatic factor [Aea-TMOF] to its receptor stimulates phosphorylation and protease processing of gut-membrane proteins

Control of Aedes aegypti larvae with Aea-TMOF mimics: aromatic derivatives of enoic acid