LIPID AND LIPOPROTEIN METABOLISM IN INSECTS

昆虫的脂质和脂蛋白代谢

• 批准号: 6018972
• 负责人: MICHAEL A WELLS
• 金额: $ 32.39万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-07-01 至 2001-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6018972
• 关键词: Bombycidae; Insecta; Manduca; SDS polyacrylamide gel electrophoresis; apolipoproteins; autoradiography; blood lipoprotein biosynthesis; cell membrane; density gradient ultracentrifugation; diacylglycerols; electron microscopy; endoplasmic reticulum; enzyme linked immunosorbent assay; fat body; fluorescence spectrometry; hemolymph; immunoaffinity chromatography; immunoprecipitation; larva; lipid biosynthesis; lipid transport; northern blottings; protein structure function; receptor binding; sterols; western blottings

DESCRIPTION (Adapted from the Applicant's Abstract): In holometabolous insects, lipid reserves are accumulated during the larval stage and stored as triacylglycerols in the fat body. These reserves are utilized in adults during flight fueled by fatty acid oxidation. In addition, lipids are essential metabolic reserves in adult insects, such as mosquitoes, that do not fuel flight by fatty acid oxidation. Despite the critical importance of lipid reserves in adult insects, relatively little is known about the mechanisms whereby they are accumulated during larval life. In many cases, this involves digestion of dietary lipids and absorption of fatty acids in the midgut, and transport of lipids from the midgut to the fat body via the hemolymph lipoprotein, lipophorin. Insects also absorb other dietary lipids in the midgut, e.g., sterols and carotenoids, and transport them in the hemolymph via lipophorin. This proposal is concerned with two aspects of the processes involved in the accumulation of lipid reserves during larval life. (1) Determination of the pathway for lipophorin biosynthesis and assembly in larval fat body. In larval Manduca sexta, lipophorin is made in the fat body as a nascent lipoprotein particle containing apolipoproteins and phospholipid, but no core or transported lipids. Until recently, it has not been possible to study the biosynthesis of lipophorin in detail due to lack of information about the apolipoproteins whose biosynthesis is coupled to production of the nascent lipophorin. However, the applicant's laboratory has recently completed sequencing the cDNA for the 3,305 amino acid precursor apolipoprotein and is now in a position to study in detail the biosynthesis and assembly of lipophorin. (2) Determination of the mechanism(s) whereby lipids are transferred between lipophorin and tissues, specifically the fat body and the midgut. Lipophorin serves as a reusable shuttle which moves lipids from one tissue to another without itself entering the tissue. This means that lipid transfer from the from the midgut to lipophorin or from lipophorin to fat body occurs at the interface between the hemolymph and the plasma membrane of the cell. However, the details of the transfer process are unknown.

描述（改编自申请人的摘要）：在跨代谢中 昆虫，脂质储量在幼虫阶段积累并存储 作为脂肪体中的三酰基甘油。 这些储量用于成人 在飞行过程中，脂肪酸氧化燃料。 另外，脂质是 成年昆虫的必需代谢储量，例如蚊子 不是通过脂肪酸氧化燃料飞行。 尽管至关重要 成年昆虫中的脂质储量，关于 它们在幼虫生命中积累的机制。 在许多情况下， 这涉及消化饮食脂质和吸收脂肪酸 中肠和脂质从中肠传输到脂肪的身体 血淋巴脂蛋白，亲脂蛋白。 昆虫还吸收其他饮食脂质 在中肠中，例如固醇和类胡萝卜素，并将其运送到 通过寄生蛋白血淋巴。 该提议与 幼虫期间脂质储量积累的过程 生活。 （1）确定亲脂蛋白生物合成的途径和 幼虫脂肪体的组装。 在幼虫甘达·塞克斯塔（Manduca Sexta 脂肪体作为新生的脂蛋白颗粒，含有载脂蛋白 和磷脂，但没有核心或运输的脂质。 直到最近， 由于无法详细研究亲脂蛋白的生物合成 缺乏有关将生物合成耦合的载脂蛋白的信息 生产新生的脂蛋白。 但是，申请人的 实验室最近完成了3,305氨基的cDNA测序 酸前体载脂蛋白，现在可以详细研究 亲脂蛋白的生物合成和组装。 （2）确定 脂质在亲脂蛋白和组织之间转移的机制， 特别是脂肪的身体和中肠。 脂蛋白可作为可重复使用的 班车将脂质从一个组织移到另一张组织，没有自身 进入组织。 这意味着脂质从 在界面上发生中肠转移到脂蛋白或从脂肪蛋白到脂肪体 在细胞的血淋巴和质膜之间。 但是， 转移过程的详细信息未知。