The distribution of brominated long-chain fatty acids in sponge and symbiont cell types from the tropical marine spongeAmphimedon terpenensis

The tropical marine spongeAmphimedon terpenensis (family Niphatidae, order Haplosclerida) has previously been shown to possess unusual lipids, including unusual fatty acids. The biosynthetic origin of these fatty acids is of interest as the sponge supports a significant population of eubacterial and cyanobacterial symbionts. The total fatty acid composition of the sponge was analyzed by gas chromatography/mass spectrometry of the methyl esters. Among the most abundant of the fatty acids in intact tissue were 16∶0, 18∶0 and 3,7,11,15-tetramethylhexadecanoic (phytanic) acid. In addition, three brominated fatty acids, (5E,9Z)-6-bromo-5,9-tetracosadienoic acid (24∶2Br), (5E,9Z)-6-bromo-5,9-pentacosadienoic acid (25∶2Br) and (5E,9Z)-6-bromo-5,9-hexacosadienoic acid (26∶2Br) were also present. The three brominated fatty acids, together with phytanic acid, were isolated from both ectosomoal (superficial) and choanosomal (internal) regions of the sponge. Analysis of extracts prepared from sponge/symbiont cells, partitioned by density gradient centrifugation on Ficoll, indicated that phytanic acid and the three brominated fatty acids were associated with sponge cells only. Further, a fatty acid methyl ester sample from intact tissue ofA. terpenensis was partitioned according to phospholipid class, and the brominated fatty acids were shown to be associated with the phosphatidylserine and phosphatidylethanolamine fractions that are commonly present in marine sponge lipids. The phosphatidylcholine and phosphatidylglycerol fractions were rich in the relatively shorter chain fatty acids (16∶0 and 18∶0). The association of brominated long-chain fatty acids (LCFA) with sponge cells has been confirmed. The findings allow comment on the use of fatty acid profiles in chemotaxonomy and permit further interpretation of LCFA biosynthetic pathways in sponges. The assignment of the sponge studied, which is currently placed asA. terpenensis, is being supported to some extent, but the species is unusual in having C₂₅ fatty acids as the major constituent in this group. Other factors, such as season or microenvironmental conditions, may influence observed fatty acid composition which tends to reduce the usefulness of fatty acid profiles as markers in sponge chemotaxonomy.     

Tape Casting of Lanthanum Chromite

The effects of process additives, ball milling, and solids loading were evaluated for tape casting suspensions of glycinenitrate-synthesized La_0.7Ca_0.31CrO₃ powder. An optimized formulation was obtained based on rheological characterization, electrokinetic sonic amplitude measurements, qualitative examination of green tapes, and the sintered microstructure. The tape casting formulation incorporated 66:34 methyl ethyl ketone/ethyl alcohol solvent, an aliphatic phosphate ester dispersant, and 80 wt% (35 vol%) solids. The best binder/plasticizer system was 12 wt% (15 vol%) poly(isobutyl methacrylate) and 5 wt% (6.3 vol%) benzyl butyl phthalate plasticizer (binder:plasticizer = 2.3). Cast tapes were sintered at 1300°C for 2 h, producing a bulk density of 96.2% theoretical, with linear shrinkage of 22% and an approximate grain size of 1.3 μm.     

Antinutritive and Oxidative Components as Mechanisms of Induced Resistance in Cotton to Helicoverpa zea

Induced resistance in cotton (Gossypium hirsutum) foliage and squares to herbivory by Helicoverpa zea (Lepidoptera: Noctuidae) is reported in this study. Induced resistance was indicated by decreased larval growth when larvae fed on previously damaged foliage or squares compared to the controls. Herbivory caused a significant decline in host nutritional quality as shown by a reduction in protein and most amino acids in both foliage and squares. Peroxidase, ascorbate oxidase, and diamine oxidase activities increased in both damaged foliage and squares, whereas levels of the nutritional antioxidant, ascorbate, were depressed after larval feeding. Larval feeding also markedly enhanced lipoxygenase activity and lipid peroxides in square tissues. Moreover, feeding damage altered the quantitative levels of phenolic compounds in foliage and squares. These results indicate a significant shift in the oxidative status of cotton plants following herbivory as indicated by increased oxidative enzyme activity, decreased levels of the nutritional antioxidant ascorbate, and increased levels of phenolic prooxidants (i.e., chlorogenic acid) and lipid peroxides.     

Liver and intestinal fatty acid-binding protein expression increases phospholipid content and alters phospholipid fatty acid composition in L-cell fibroblasts

Although fatty acid-binding proteins (FABP) differentially affect fatty acid uptake, nothing is known regarding their role(s) in determining cellular phospholipid levels and phospholipid fatty acid composition. The effects of liver (L)- and intestinal (I)-FABP expression on these parameters were determined using stably transfected L-cells. Expression of L- and I-FABP increased cellular total phospholipid mass (nmol/mg protein) 1.7- and 1.3-fold relative to controls, respectively. L-FABP expression increased the masses of choline glycerophospholipids (ChoGpl) 1.5-fold, phosphatidylserine (PtdSer) 5.6-fold, ethanolamine glycerophospholipids 1.4-fold, sphingomyelin 1.7-fold, and phosphatidylinositol 2.6-fold. In contrast, I-FABP expression only increased the masses of ChoGpl and PtdSer, 1.2- and 3.1-fold, respectively. Surprisingly, both L- and I-FABP expression increased ethanolamine plasmalogen mass 1.6- and 1.1-fold, respectively, while choline plasmalogen mass was increased 2.3- and 1.7-fold, respectively. The increase in phospholipid levels resulted in dramatic 48 and 33% decreases in the cholesterol-to-phospholipid ratio in L- and I-FABP expressing cells, respectively. L-FABP expression generally increased polyunsaturated fatty acids, primarily by increasing 20∶4n−6 and 22∶6n−3, while decreasing 18∶1n−9 and 16∶1n−7. I-FABP expression generally increased only 20∶4n−6 proportions. Hence, expression of both I- and L-FABP differentially affected phospholipid mass, class composition, and acyl chain composition. Although both proteins enhanced phospholipid synthesis, the effect of L-FABP was much greater, consistent with previous work suggesting that these two FABP differentially affect lipid metabolism.