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Rhodnius prolixus LIPOPHORIN: LIPID COMPOSITION AND EFFECT OF HIGH TEMPERATURE ON PHYSIOLOGICAL ROLE
Author(s) -
Majerowicz David,
Cezimbra Milton P.,
AlvesBezerra Michele,
Entringer Petter F.,
Atella Georgia C.,
SolaPenna Mauro,
MeyerFernandes José R.,
Gondim Katia C.
Publication year - 2013
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.21080
Subject(s) - rhodnius prolixus , biology , phosphatidylethanolamine , phospholipid , phosphatidylcholine , adipokinetic hormone , diacylglycerol kinase , biochemistry , chromatography , fat body , chemistry , insect , membrane , ecology , protein kinase c , gene , enzyme
Lipophorin is a major lipoprotein that transports lipids in insects. In R hodnius prolixus, it transports lipids from midgut and fat body to the oocytes. Analysis by thin‐layer chromatography and densitometry identified the major lipid classes present in the lipoprotein as diacylglycerol, hydrocarbons, cholesterol, and phospholipids ( PL s), mainly phosphatidylethanolamine and phosphatidylcholine. The effect of preincubation at elevated temperatures on lipophorin capacity to deliver or receive lipids was studied. Transfer of PL s to the ovaries was only inhibited after preincubation of lipophorin at temperatures higher than 55°C. When it was pretreated at 75°C, maximal inhibition of phospholipid transfer was observed after 3‐min heating and no difference was observed after longer times, up to 60 min. The same activity was also obtained when lipophorin was heated for 20 min at 75°C at protein concentrations from 0.2 to 10 mg/ml. After preincubation at 55°C, the same rate of lipophorin loading with PL s at the fat body was still present, and 30% of the activity was observed at 75°C. The effect of temperature on lipophorin was also analyzed by turbidity and intrinsic fluorescence determinations. Turbidity of a lipophorin solution started to increase after preincubations at temperatures higher than 65°C. Emission fluorescence spectra were obtained for lipophorin, and the spectral area decreased after preincubations at 85°C or above. These data indicated no difference in the spectral center of mass at any tested temperature. Altogether, these results demonstrate that lipophorin from R . prolixus is very resistant to high temperatures.