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

Effect of the environment and fasting on the lipid and fatty acid composition of Diplodom patagonicus

Some effects of food, habitat and temperature on the lipid composition of a freshwater mollusk, Diplodom patagonicus, were studied. Animals kept and fasted up to 60 days in an aquarium at 9 C and 20 C showed a decrease of the total lipid content that corresponded to a decrease of triacylglycerols and diacylglycerol ethers. This decrease evoked an increase of polar-to-nonpolar lipid ratio. However, no significant change in the total fatty acid composition was shown. Moreover, a decrease of temperature from 20 C to 9 C decreased the incorporation of labeled linoleic and α-linolenic acid into the lipids, but did not modify the unsaturated: saturated acid ratio of the mollusk lipids during this period. A change of habitat from lake to estuary changed very significantly the fatty acid composition of the animal. The ω6 acids, linoleic and arachidonic, typical of D. patagonicus living in the lake, were partially replaced by ω3 acids. That this change was due to a change of food composition was indicated by the fatty acids of corresponding sediments. Therefore, the fatty acid composition of D. patagonicus is highly sensitive to food composition and varies little with temperature and seasonal changes.Facultad de Ciencias Médica

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

Triacylglycerol consumption during spore germination of vesicular-arbuscular mycorrhizal fungi

Lipids and fatty acids of spores of the vesicular-arbuscular mycorrhizal fungus Glomus versiforme were identified and quantitatively determined at different times of germination. Triacylglycerols were, by far, the most abundant lipid (38% on a wet-weight basis). Phosphatidylethanolamine, together with minor quantities of other phospholipids, was the main polar lipid. Palmitoleic, palmitic and oleic acids were quantitatively the most important fatty acids in total lipids, and even more so in the triacylglycerol fraction. Minor percentages of fatty acids, identified as ω3 and ω6 polyunsaturated, completed the fatty acid spectra. Germination of G. versiforme spores evokes a continuous decrease of triacylglycerols and an increase of phospholipids. The balance of fatty acids during germination suggests either a degradation or a transference of fatty acids from triacylglycerols to phospholipids.Instituto de Investigaciones Bioquímicas de La PlataInstituto de Botánica "Dr. Carlos Spegazzini

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

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

Extracellular lipolytic activity in <i>Phoma glomerata</i>

Several properties of the lipolytic activity exhibited by the conidial fungus Phoma glomerata were studied. Lipolytic activity in an aqueous buffer medium was measured on triacylglycerol, phosphoglyceride and cholesterol ester under different experimental conditions. The effect of storage temperature on the stability of the hydrolytic activity, and optimal conditions of temperature and time of maximal activity were determined. The optimal conditions for maximal lipolytic activity were found to be 40–50 °C and 1 h. The activity released to the medium by 1 mg cells for 1 h at 40 °C was stated as the enzyme released unit (ERU). The protein fraction of MW > 50 kDa obtained by ultrafiltration of the medium, was active on the three substrates assayed, and it showed a non-specific hydrolytic activity on both the 1- and 2-acyl esters either in the neutral glyceride or in the phosphoglyceride. A protein of Mr approx. 75 kDa was the only one that showed esterase activity. The crude medium, stored at −15 °C, maintained its initial hydrolytic activity on triacylglycerol for at least 42 days, though when it was kept for 10 days at 4 °C, the activity fell to 50%. Kinetic parameters using substrates such as triolein (TO), dipalmitoyl phosphatidylcholine (DPPC) and cholesteryl oleate (ChoO), were comparatively evaluated. The activity of the enzyme in the hydrolysis of TO showed the highest values, whereas the maximal specific activities were less when the enzyme was assayed against DPPC and ChoO.Facultad de Ciencias Naturales y MuseoInstituto de Investigaciones Bioquímicas de La PlataInstituto de Botánica "Dr. Carlos Spegazzini

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