| Lipid metabolism in Rhodnius prolixus (Hemiptera: Reduviidae): role of a midgut triacylglycerol-lipase. | |
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MedLine Citation:
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PMID: 17517335 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The utilization of dietary lipids was studied in adult females of Rhodnius prolixus with the use of radiolabeled triacylglycerol (TAG). It was shown that (3)H-triolein, when added to blood meal, was hydrolyzed to free fatty acids in the posterior midgut lumen. Subsequently, free fatty acids were absorbed by posterior midgut epithelium and used in the synthesis of phospholipids, diacylglycerol (DAG) and TAG. Phospholipids, DAG and free fatty acids were then found in hemolymph, from where they were rapidly cleared, and label was found in the fat body, mainly associated with TAG. Radioactive lipids, especially TAG and phospholipids, also accumulated in the ovaries. The TAG-lipase activities of posterior midgut luminal content and tissue were characterized by incubation of these samples with (3)H-triolein in the presence of the detergent Triton X-100 and determination of the amounts of released radioactive free fatty acids. Under the conditions employed here, the release of free fatty acids was proportional to the incubation time and to the amount of sample obtained from insect midgut (enzyme source) that was added. TAG-lipase activities were affected by pH and posterior midgut tissue showed optimum activity around pH 7.0-7.5, but the luminal content had the highest activities as pH decreased. Differences in activities were observed according to calcium concentration in the medium. TAG-lipase activities were also affected by the concentration of NaCl and were activated in the presence of increasing salt concentrations. These activities were inhibited by phenylmethylsulphonyl fluoride (PMSF). On the second day after blood meal, when digestion is very intense, TAG-lipase activities were maximal and then gradually decreased. |
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Authors:
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Luciano A M Grillo; David Majerowicz; Katia C Gondim |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2007-03-12 |
Journal Detail:
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Title: Insect biochemistry and molecular biology Volume: 37 ISSN: 0965-1748 ISO Abbreviation: Insect Biochem. Mol. Biol. Publication Date: 2007 Jun |
Date Detail:
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Created Date: 2007-05-22 Completed Date: 2007-07-25 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9207282 Medline TA: Insect Biochem Mol Biol Country: England |
Other Details:
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Languages: eng Pagination: 579-88 Citation Subset: IM |
Affiliation:
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Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Blood / metabolism Digestive System / metabolism Female Lipase / metabolism* Lipid Metabolism* Rhodnius / enzymology*, metabolism* Triolein / metabolism |
| Chemical | |
Reg. No./Substance:
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122-32-7/Triolein; EC 3.1.1.3/Lipase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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