Manduca sexta

Martel, R.R. and Law, J.H., Purification and properties of an ommochrome-binding protein from the hemolymph of the tobacco homworm, Manduca sexta, J. Biol. Chem., 266, 21392, 1991. 

Kanost MR, Zepp MK, Ladendorff NE, Andersson LA 1994 Isolation and characterization of a hemocyte aggregation inhibitor from hemolymph of Manduca sexta larvae. Arch Insect Biochem Physiol 27 123—136... 

Tsuchida, K. and Wells, M. A. 1990. Isolation and characterization of a lipoprotein receptor from the fat body of an insect, Manduca sexta. J. Biol. Chem., 265(10) 5761-5767. 

Tsuchida, K., Soulages, J. L., Moribayashi, A., Suzuki, K., Maekawa, H., and Wells, M. A. 1997. Purification and properties of a lipid transfer particle from Bombyx mori Comparison to the lipid transfer particle from Manduca sexta. Biochim. Biophys. Acta, 1337(l) 57-65. 

Fukamizo, T. and Kramer, K.J. (1987) Effect of 20-hydroxyecdysone on chitinase and P-Af-acetylglucosaminidase during the larval-pupal transformation on Manduca sexta (L.). Insect Biochemistry 17, 547-550. 

Kramer, K.J., Corpuz, L., Choi, H.K. and Muthukrishnan, S. (1993) Sequence of a cDNA and expression of the gene encoding epidermal and gut chitinases of Manduca sexta. Insect Biochemistry and Molecular Biology 23, 691-701. 

Barbour, J.D., Farrar Jr., R.R. and Kennedy, G.G. (1993). Interaction of Manduca sexta resistance in tomato with insect predators of Helicoverpa zea. Entomologia Experimentalis Et Appilcata 68 143-155. 

Tobacco homworms (Manduca sexta) from a field sprayed with 840 mg diazinon/ha contained no detectable residues of diazoxon. Only one sample, collected about 4 h after spraying, exceeded 1.0 mg diazinon/kg body weight. No diazinon residues in these insects were detectable after 18 days. 

Manduca sexta. The brief review presented here focuses on the functional organization and physiology of a sexually dimorphic olfactory subsystem in this species [also reviewed elsewhere (19, 23, 40-42)]. 

The effect of caffeine has been tested with insect herbivores. Tobacco horn-worms, Manduca sexta, die from a diet with 0.3% caffeine, and the beetle Calioso-bruchus chincnsis becomes sterile at a concentration of 1.5% (Nathanson, 1984). However, experiments showed that caffeine does not protect the coffee plant against the leaf miner Perileucoptera coffedla, one of the major pests of coffee (Filho and Mazzafera, 2000). 

The 29-fluorophytosterols, members of a new class of selective pro-insecticides, have been synthesized and examined m vivo in tobacco hornworms. Dealkylation at C-24 of the steroid side chain by insects releases the latent poison fluoroacetate, resulting in dose-dependent reductions in growth rate, maximum weight, and survival when fed at 1 to 100 ppm to Manduca sexta. 

Table 1. Dealkylation of [29- H]-phytosterols in vivo by Manduca sexta ...

Substitution of fluorine for hydrogen at C-25 and C-26 of phytosterols and at C-20, C-22, C-24 or C-25 of cholesterol provided compounds which did not affect Manduca sexta growth or development significantly at 50 ppm in the diet(15). In contrast, we predicted that the C-29 fluorophytosterols (Fig. 1, X=F) would release the metabolic equivalent of fluoroacetate as a result of dealkylation(, ). 

The 29-fluorophytosterols (Fig. 3) all showed significant impairment of growth and development of larval tobacco hornworms when fed at 1 to 100 ppm to Manduca sexta. It is clear that the A22 sterols and were more toxic and caused more severe... 

Figure 4. Effects of 29-fluorophytosterols on growth and pupation of Manduca sexta fed from second instar on 50 ppm 29F-sterol in diet.

In addition to the circumstantial iji vivo evidence for fluorocitrate as the ultimate biochemical lesion we desired to demonstrate unambiguously that it was produced as a metabolite of 29-fluorostigmasterol. The toxicity of fluorocitrate and the resulting lethal accumulation of citrate in mouse, fly and cockroach tissues have been shown in early experiments with fluoroacetamide and fluoroacetate(24). However, to our knowledge, complete characterization of (2R,3R)-2-fluorocitrate as the lethal metabolite in vivo has not previously been reported. We thus prepared( ) [29- ]-29-fluorostigmasterol, [29- H]-29-Huorositosterol and [16- H]-16-fluorohexadec-9-enoic acid to enable isolation of [2-3H]-2-fluorocitrate from vivo incubations using Manduca sexta. 

Cuticular diterpenes-duvanes and labdanes. Cutler have found that the cuticular diterpenes of green tobacco have both allelopathic and insect-deterrent effects (38). Present in the cuticle are duvane and/or labdane diterpenes (Figure 3) The levels of these specific cuticular components are believed to be responsible for the observed resistance of some types of tobacco to green peach aphids Myzus persicae (Sulzer), tobacco budworm Heliothis virescens (F.), and tobacco hornworm Manduca sexta (L.) (39). 

We initiated this line of research by testing isolated compounds for their effects upon two Insects, the grasshopper (Melanoplus bivitattus or 11.. sanouinipes) and the tobacco hornworm, Manduca sexta. We could thereby test for activity against adult... 

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