title: Triacylglycerol catabolism in the prawn Macrobrachium borellii (Crustacea: Palaemoniade).
abstract: While invertebrates store neutral lipids as their major energy source, little is known about triacylglycerol (TAG) class composition and their differential catabolism in aquatic arthropods. This study focuses on the composition of the main energy source and its catabolism by lipase from the midgut gland (hepatopancreas) of the crustacean Macrobrachium borellii. Silver-ion thin-layer chromatography of prawn large TAG deposit (80% of total lipids) and its subsequent fatty acid analysis by gas chromatography allowed the identification of 4 major fractions. These are composed of fatty acids of decreasing unsaturation and carbon chain length, the predominant being 18:1n-9. Fraction I, the most unsaturated one, contained mainly 20:5n-3; fraction II 18:2n-6; fraction III 18:1n-9 while the most saturated fraction contained mostly 16:0. Hepatopancreas main lipase (Mr 72 kDa) cross-reacted with polyclonal antibodies against insect lipase, was not dependent on the presence of Ca(2+) and had an optimum activity at 40°C and pH 8.0. Kinetic analysis showed a Michaelis-Menten behavior. A substrate competition assay evidenced lipase specificity following the order: 18:1n-9-TAG>PUFA-enriched-TAG>16:0-TAG different from that in vertebrates. These data indicate there is a reasonable correspondence between the fatty acid composition of TAG and the substrate specificity of lipase, which may be an important factor in determining which fatty acids are mobilized during lipolysis for oxidation in crustaceans.
authors: Instituto de Investigaciones Bioquímicas de La Plata, CONICET-CCT La Plata - UNLP, Universidad Nacional de La Plata, Argentina. yanina.pasquevich@gmail.com
authors: M Y
authors: MY
authors: Pasquevich
authors: M S
authors: MS
authors: Dreon
authors: S
authors: S
authors: Lavarías
authors: H
authors: H
authors: Heras
mesh_terms: D000818:Animals; D003445:Crustacea / Q000737:chemistry / Q000378:metabolism*; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000737:chemistry / Q000378:metabolism; D043143:Hepatopancreas / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism; D007700:Kinetics; D008049:Lipase / Q000737:chemistry / Q000378:metabolism*; D050356:Lipid Metabolism / Q000502:physiology*; D008660:Metabolism; D033541:Palaemonidae / Q000737:chemistry / Q000378:metabolism*; D012680:Sensitivity and Specificity; D013379:Substrate Specificity; D014280:Triglycerides / Q000737:chemistry / Q000378:metabolism*
chemical_list: D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D014280:Triglycerides; D008049:Lipase