Hemocyanin as an apolipoprotein in the hemolymph of the cephalopod Octopus tehuelchus

Fil: Heras, Horacio. Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP); UNLPFil: Pollero, Ricardo José. Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP); UNL

Blood lipids of the small octopus Octopus tehuelchus (Mollusca: Cephalopoda) at different stages of sexual maturation

Fil: Heras, Horacio. Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP); UNLPFil: Pollero, Ricardo José. Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP); UNL

Lipid Circulation in Spiders - Transport of Phospholipids, Free Acids and Triacylglycerols as the Major Lipid Classes by a High-Density-Lipoprotein Fraction Isolated from Plasma of Polybetes Pythagoricus

Fil: Cunningham, Mónica Liliana. Instituto de Investigaciones Bioquimicas de La Plata (INIBIOLP); Fcultad de Ciencias Naturales y Museo; Universidad Nacional de La PlataFil: Pollero, Ricardo José. Instituto de Investigaciones Bioquimicas de La Plata (INIBIOLP); Fcultad de Ciencias Naturales y Museo; Universidad Nacional de La PlataFil: Gonzalez, Alda. Instituto de Investigaciones Bioquimicas de La Plata (INIBIOLP); Fcultad de Ciencias Naturales y Museo; Universidad Nacional de La Plat

Glomus Antarcticum Sp-Nov, a Vesicular-Arbuscular Mycorrhizal Fungus from Antarctica

Fil: Cabello, Marta Noemí. División Instituto Spegazzini. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Gaspar, Laura. Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP). Universidad Nacional de La Plata; ArgentinaFil: Pollero, Ricardo José. Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP). Universidad Nacional de La Plata; Argentin

Effect of fenitrothion on dipalmitoyl and 1-palmitoyl-2-oleoylphosphatidylcholine bilayers

The effects of the organophosphorous insecticide fenitrothion (phosphorothioic acid, O,O-dimethyl O-(3-methyl-4-nitrophenyl) ester; FS) on the physical state of pure dipalmitoyl (DPPC) and 1-palmitoyl-2- oleoylphosphatidylcholine (POPC) membranes were investigated. FS lowers the phase transition temperature of DPPC. It has no large effects on the DPPC gel phase, but it increases the order of the liquid-crystalline state of DPPC and POPC. FS also decreases 1,6-diphenyl-1,3,5-hexatriene (DPH) lifetime (τ) in the DPPC and POPC liquid-crystalline states. Since a direct quenching of DPH emission by FS was ruled out, τ shortening is assigned to an increased water penetration in the bilayer. The effect of FS is different from most perturbing agents for which an increased order is accompanied by a higher τ. Furthermore, quenching of DPH by KI was increased by FS in POPC liposomes indicating an increased accessibility of the quencher to the hydrophobic core where DPH distributes. The effect of FS on dipole relaxation at the hydrophilic-hydrophobic interface of POPC bilayers was studied with 2- dimethylamino-6-lauroylnaphthalene (Laurdan). FS produces a decrease in Laurdan τ and a narrowing of its emission band. FS significantly increases the generalized polarization values at both emission band ends. These results indicate that FS may allow the coexistence of microdomains that have different physical properties.Facultad de Ciencias MédicasInstituto de Investigaciones Bioquímicas de La Plat

Lipid circulation in spiders : Transport of phospholipids, free acids and triacylglycerols as the major lipid classes by a high-density lipoprotein fraction isolated from plasma of <i>Polybetes pythagoricus</i>

Abstract A high-density lipoprotein (HDL) fraction was isolated from the hemolymphatic plasma of the spider Polybetes pythagoricus by density-gradient ultracentrifugation. Hydrated density (1.13 g/ml), electrophoretic mobility (SDS—PAGE) of apoproteins and lipid classes composition were determined. Lipids were identified by HP-TLC and auxiliary techniques; they were quantified by TLC-FID. The protein moiety is composed of two main apoproteins (250 and 76 kDa, respectively) and several polypeptides of low molecular weight. It resembles the apoliphorins of insects and some other arachnids. The lipid composition differs from most lipophorins. Phospholipids amount to more than 60% of total lipids, while diacylglycerols (2.4%) are supplanted by triacylglycerols (16.5%) as the main circulating energetic lipids.Facultad de Ciencias Naturales y MuseoInstituto de Investigaciones Bioquímicas de La Plat

Variations in the lipid composition of alfalfa roots during colonization with the arbuscular mycorrhizal fungus Glomus versiforme

Lipids and their fatty acids were characterized and quantified during the development of the arbuscular mycorrhizal fungus Glomus versiforme in roots of alfalfa (Medicago sativa). A net increase in root total lipids was observed and was proportional to the development of arbuscular mycorrhizal fungus colonization. Triacylglycerols were the main lipid class in colonized roots and appear to have been synthesized by fungi. The increase of palmitoleic acid (characteristic of triacylglycerols from arbuscular mycorrhizal fungus) in roots colonized with G. versiforme reinforced this suggestion. Phosphatidylethanolamine and to a minor extent phosphatidylcholine also increased during the endophyte growth. Variations in the lipid classes of external mycelia isolated from one-, two- and three-mo old colonized roots with G. versiforme were also analyzed. Despite the continuous increase of triacylglycerols and phosphatidylethanolamine observed, the polar lipid class predominated in the external mycelia isolated from one- -mo old colonized roots and the neutral lipid class prevailed in the external mycelia obtained from three-mo old mycorrhizal roots. Biosynthesis of triacylglycerols in intra- and extramatrical mycelia as well as an induced synthesis of polar lipids in roots are suggested as the consequence of fungi colonization.Instituto de Botánica "Dr. Carlos Spegazzini"Instituto de Investigaciones Bioquímicas de La Plat

Composition and biosynthesis of fatty acids in Pyramimonas grossii

The green algaPyramimonas grossii orginating in the coastal waters of the Atlantic Ocean Argentina was subcultured until a monoalgal culture was obtained. The fatty acid composition of the alga grown in a mineral medium at 12 C was determined by gas liquid chromatography (GLC) on 2 columns. The major fatty acids were oleic, linoleic, palmitic and α-linolenic acids, but the 20-carbon polyunsaturated acids, 20∶4ω6 and 20∶5ω3, respectively, belonging to the linoleic and α-linolenic series, were also found. Incubation with [14C] oleate, [14C] acetate, [14C] linoleate and [14C] α-linolenate suggests that linoleate is not directly converted to α-linolenate. [14C] Acetate was easily converted to palmitic, palmitoleic and oleic acids. However, after 48 hr of incubation, only traces of radioactivity were detected in linoleic acid and no label was found in α-linolenic acid.Facultad de Ciencias Médica

Seasonal changes in lipid and fatty acid composition of the freshwater mollusk, Diplodom patagonicus

Diplodom patagonicus is a freshwater bivalve mollusk living in lakes of the patagonian Andes mountains in Argentina. Lipid composition and seasonal changes in the mollusk were studied in the natural habitat. In addition to common nonpolar and polar lipids, small amounts of alk-1-enyldiacylglycerol ethers and significant quantities of ceramide aminoethyl phosphonate were present. Total lipid content changed during the year, primarily because of decreased triacylglycerols in winter. The fatty acid composition of the lipids, remarkably different from that of marine bivalves, and even from other fresh water animals, was especially rich in the ω6 fatty acids, linoleic and arachidonic (ca. 25%), and poor in the ω3 acids, 20∶5 and 22∶6. The ω6/ω3 acid ratio was ca. 2, which is very high compared to marine bivalves. The fatty acid composition and the ω6/ω3 acid ratio were constant during the whole year, suggesting a very stable diet, rich in vegetal detritus and poor in diatoms. The influence of environmental temperature fluctuation with season on fatty acid composition also was negible. Modest proportions of 22∶2 nonmethylene-interrupted (NMI) acids were detected and confirmed by mass spectrometry. It was shown that 20∶2 NMI acids were absent.Facultad de Ciencias Médica

Transfer of lipids between hemolymph and hepatopancreas in the shrimp Macrobrachium borellii

Crustacean lipids are transported in the hemolymph by an HDL. The hepatopancreas is the most important and active organ regarding lipid metabolism, so we studied the interchange of FA and acylglycerols between both components of the hepatopancreas-hemolymph system in the decapod crustacean Macrobrachium borellii. The hepatopancreas and a sole plasma lipoprotein were labeled by in vivo incubations with 14C palmitic acid injected into the hemolymph. Then they were incubated in vitro with unlabeled hepatopancreas and hemolymph, and the transfer of lipids between them was measured by radiochromatographic techniques. It was determined in vivo that more than 80% of the circulating palmitic acid was taken up by the hepatopancreas and incorporated into PC and TAG. Both classes of lipids, but mainly PC, were transferred back from tissues to the hemolymph. Lipid transfer was also demonstrated in vitro. The transfer of PC (30% of labeling) as well as that of FFA (48% of labeling) from hemolymph to hepatopancreas was determined. On the other hand, FFA were released more efficiently than the acylglycerols from intact hepatopancreas to hemolymph, and they were the only lipid transferred when the hepatopancreas had been previously washed.Instituto de Investigaciones Bioquímicas de La Plat