An extensive literature exists which describes the biochemical and biophysical properties of human and rat lipoproteins. Other vertebrate and invertebrate systems have been studied less extensively. In light of recent NIH guidelines calling for a reduction in the use of vertebrate animals and an exploration of the possible use of non-vertebrate model systems, it seems timely and appropriate to propose a detailed study of one such model system, the tobacco hornworm, Manduca sexta. The blood of this insect contains a single high density lipoprotein, which is make in the fat body. During the larval stages the lipoprotein contains one copy each of two glycosylated apoproteins (apolipophorin-I, apoLp-I, Mr approximately equal to 250,000 and apolipophorin-II, apoLp-II, Mr approximately equal to 80,000). The lipids are primarily phospholipid and diacylglycerol, which are present in about equimolar amounts. In the adult moth, the lipoprotein contains, in addition to apoLp-I and -II, 2 molecules of a non- glycosylated apoprotein, apoLp-III (Mr equal to 18,400). There are also high concentrations of apoLp-III free in the hemolymph. During flight the adult uses fatty acid as an energy source in flight muscle. The fatty acids are transported from the storage site to the muscle in the form of diacylglycerol via a flight specific lipoprotein. This flight specific lipoprotein is a low density lipoprotein which is derived from the high density lipoprotein by addition of diacylglycerol. In the process of diacylglycerol addition, 14 additional molecules of apoLp-III become associated with the lipoprotein and serve to stabilize the increment of lipid-water interface created by the addition of diacylglycerol. We propose the following specific aims for this grant: 1) a study of the structure-function relationships in apoLp- III: 2) a study of the assembly and secretion of the lipoprotein in both larvae and adults; 3) biochemical and morphological characterization of the fat body during development; 4) a study of the control of apoprotein gene expression; and 5) a study of hormonal control of lipoprotein metabolism.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL039116-02
Application #
3355720
Study Section
Physiological Chemistry Study Section (PC)
Project Start
1987-09-30
Project End
1992-09-29
Budget Start
1988-09-30
Budget End
1989-09-29
Support Year
2
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of Arizona
Department
Type
Schools of Medicine
DUNS #
City
Tucson
State
AZ
Country
United States
Zip Code
85722
Kanost, M R; Prasad, S V; Huang, Y et al. (1995) Regulation of serpin gene-1 in Manduca sexta. Insect Biochem Mol Biol 25:285-91
Kanost, M R; Sparks, K A; Wells, M A (1995) Isolation and characterization of apolipophorin-III from the giant water bug (Lethocerus medius). Insect Biochem Mol Biol 25:759-64
Soulages, J L; Wells, M A (1994) Lipophorin: the structure of an insect lipoprotein and its role in lipid transport in insects. Adv Protein Chem 45:371-415
Frohlich, D R; Wells, M A (1994) Codon usage patterns among genes for lepidopteran hemolymph proteins. J Mol Evol 38:476-81
Soulages, J L; Wells, M A (1994) Effect of diacylglycerol content on some physicochemical properties of the insect lipoprotein, lipophorin. Correlation with the binding of apolipophorin-III. Biochemistry 33:2356-62
Smith, A F; Owen, L M; Strobel, L M et al. (1994) Exchangeable apolipoproteins of insects share a common structural motif. J Lipid Res 35:1976-84
Spoonamore, J E; Frohlich, D R; Wells, M A (1993) p-Nitrophenylacetate hydrolysis by honey bee esterases: kinetics and inhibition. Xenobiotica 23:279-84
Frohlich, D R; Robinson, A S; Wells, M A (1993) Mediterranean fruit fly, Ceratitis capitata (Wiedemann), mitochondrial DNA: genes and secondary structures for six t-RNAs. Insect Mol Biol 1:165-9
Benning, M M; Smith, A F; Wells, M A et al. (1992) Crystallization, structure determination and least-squares refinement to 1.75 A resolution of the fatty-acid-binding protein isolated from Manduca sexta L. J Mol Biol 228:208-19
Hanneman, E H; Kanost, M R (1992) Differential alaserpin expression during development of the antennae in the tobacco hawkmoth, Manduca sexta. Arch Insect Biochem Physiol 19:39-52

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