Trace Lipid Research Articles

Physiochemical and functional properties of Moringa oleifera protein obtained by isoelectric precipitation

The work investigated the effect of extraction pH (10 or 11) and precipitation pH (4 or 4.5) on the physicochemical and functional properties of Moringa oleifera protein. The physicochemical characteristics of Moringa leaf powder were analyzed using proximate quantification based on AOAC standard methods. The thermal, spectral, x-ray diffraction data were collected using the differential scanning calorimetric, Fourier transform infrared spectroscopy (FTIR), and wide-angle x-ray diffraction. The extraction at pH 10 and the precipitation process at pH 4.5 generated the highest protein content of 58.88%. Some of the functional properties of this pH combination were emulsion activity at 29.67%, emulsion stability at 50.45%, protein solubility at 32.36%, and water absorption capacity of 4.78 mL water/g. The thermal properties suggested the denaturation temperature of Moringa protein powder at 75°C, which was comparable to that previously reported plantbased protein isolate. FTIR and x-ray spectra argued the domination of amorphous protein fraction with a trace of lipid and carbohydrate. With these characteristics, protein has great potential to be used for food and drug applications.

Physico-Chemical analysis of some medicinal plants growing in Algeria: Allium sativum, Allium cepa and Foenuculum vulgare

This study aims to investigate, the physic-ochemical characterization of Allium sativum, Allium cepa and Foenuculum vulgare. The analysis which carried out on these plants includes pH, titratable acidity, fiber, fat, sugars, soluble solids, pectin and protein. The results from the study of three medicinal plants, show that: Allium sativum, present a low acid vegetable (6.10 ± 0.005), rich in water (63.67% ± 0.1131) and sugars (25.6g / 100g ± 0.034), its pectin content is (2.89 % ± 0.1619) and fiber (1.47% ± 0.007), but contains a low protein content of (0.04mg / ml ± 0.0028) and traces of lipids. Allium cepa had a low acid vegetable (5.42 ± 0.0707), rich in water (92.20% ± 0.0212), sugars (13.16g / 100g ± 0.1416), pectin (3.102% ± 0.0459), and fiber (2.12% ± 0.070). Its protein content (0.1mg / ml ± 0.007) was low, and traces of lipids. For, Foenuculum vulgare, a slightly acidic vegetable (6.02 ± 0.0057), highly rich in water (95.34% ± 0.00), sugars (16.80g / 100g ± 0.1983), dietary fiber (12.20% ± 0, 0785), and pectin (3.79% ± 0.07). However, contains low protein content (0.034mg / ml ± 0.0098), and traces of lipids. The results obtained from this study show that the three plants garlic, onion and fennel have a good chemical composition.

Mechanisms of lipid preservation in archaeological clay ceramics revealed by mass spectrometry imaging

Traces of lipids, absorbed and preserved for millennia within the inorganic matrix of ceramic vessels, act as molecular fossils and provide manifold information about past people's subsistence, diet, and rituals. It is widely assumed that lipids become preserved after adsorption into nano- to micrometer-sized pores, but to this day the distribution of these lipids in the ceramics was virtually unknown, which severely limits our understanding about the process of lipid preservation. Here we use secondary ion mass spectrometry (SIMS) imaging for direct in situ analysis of lipids absorbed in 700- to 2,000-y-old archaeological pottery. After sectioning from larger sherds, wall cross-sections of smaller fragments were used for SIMS analysis. Lipids were found in relatively large zones of 5- to 400-µm diameter, which does not support the notion of absorption only into individual nanometer-scale pores but indicates that more macroscopic structures in the ceramics are involved in lipid preservation as well. Furthermore, lipids were found concentrated on calcium carbonate inclusions in the ceramics, which suggests that precipitation of fatty acids as calcium salts is an important aspect of lipid preservation in archaeological samples. This has important implications for analytical methods based on extraction of lipids from archaeological ceramics and needs to be considered to maximize the yield and available information from each unique sample.

Biochemical and structural comparative study between bird and mammal pancreatic colipases

Three colipases were purified from pancreas of two birds (ostrich and turkey) and one mammal (dromedary). After acidic and/or heat treatment and precipitation by sulfate ammonium and then ethanol, cofactors were purified by Sephadex G-50 gel filtration followed by ion-exchange chromatography first on Mono S and then on Mono Q. One molecular form was obtained from each species with a molecular mass of approximately 10 kDa. Cofactors were not glycosylated. The N-terminal sequences of the three purified cofactors showed high sequence homology. A 90 amino acid sequence of the ostrich cofactor was established based on peptide sequences from four different digests of the denaturated protein using trypsin, chymotrypsin, thermolysin, or staphylococcal protease. This sequence exhibited a high degree of homology with chicken and mammal cofactors. Bile salt-inhibited pancreatic lipases from five species were activated to variable extents by colipases from bird and mammal origins. The bird pancreatic lipase-colipase system appears to be functionally similar to homologous lipolytic systems from higher mammals. Our comparative study showed that mammal colipase presents a lower activation level toward bird lipases than the bird counterpart. Three-dimensional modeling of ostrich colipase suggested a structural explanation of this fact.

Lipid dynamics in the embryos of Patiriella species (Asteroidea) with divergent modes of development.

Evolution of lecithotrophic development in sea stars involved a modification in maternal provisioning from the production of yolk-dominated to lipid-dominated eggs. The dynamics of lipid reserves in the embryos of four Patiriella species differing in their lipid provisions were examined. Patiriella regularis had small yolk protein-dominated eggs (150 microm in diameter) and an ancestral mode of development through planktotrophic larvae. Patiriella calcar, Patiriella exigua and Patiriella pseudoexigua had large eggs (390-440 microm in diameter) and lecithotrophic planktonic, benthic and intragonadal larvae, respectively. Patiriella exigua deposited negatively buoyant eggs containing substantial yolk protein and lipid reserves onto the substratum. In contrast, the planktonic eggs of P. calcar and the intragonadal eggs of P. pseudoexigua were dominated by lipid and were neutrally and positively buoyant, respectively. By the blastula stage there was little trace of lipid in P. regularis embryos. Blastulae of the lecithotrophic developers, by contrast, had conspicuous lipid droplets distributed through their cells. In parallel with the change from cuboidal to columnar epithelium during the blastula to gastrula transition, lipid reserves became redistributed into the basal cytoplasm. The extent of lipid transport reflected the amount of lipid reserves. In P. pseudoexigua embryos with the greatest lipid load, basal shunting was followed by secretion of lipid into the blastocoele where it was stored for the perimetamorphic period. Evolution of lecithotrophy in Patiriella appears to reflect selection to provide metamorphic stages with nutrients normally accrued by feeding larvae with the consequence that early development is burdened by voluminous, potentially inert nutritive stores. Lipid redistribution coincident with a major developmental stage transition may be required to facilitate unimpeded morphogenesis. This phenomenon may be characteristic of lecithotrophic development in echinoderms and appears pre-adaptive for extrusion of lipid in species like P. pseudoexigua with particularly extensive lipid reserves.

The Envelope Layers of Mycobacteria with Reference to their Pathogenicity

The review discusses current knowledge of the biosynthesis, composition and arrangement of the mycobacterial envelope, describes the biological activities of the constituents and considers how these activities may be relevant to the pathology of mycobacterial disease. The envelope possesses three structural components: plasma membrane, wall and capsule. Although the major biomolecules occurring in each of these parts are known, the distribution of numerous minor substances is poorly understood; an attempt has been made to assign them to particular positions on rational grounds. The plasma membrane appears to be a typical bacterial membrane but, though vital to the mycobacterium, probably plays little part in pathological processes. The wall partly resembles a Gram-positive wall, but is unusual in having a layer of lipid (mycolate esters) which is probably arranged to form a permeability barrier to polar molecules. The capsule, whose chemical composition has only recently been recognized, consists of polysaccharide and protein with traces of lipid; the arrangement of these components is imperfectly understood. Constituents of all parts of the envelope have biological activities which may be relevant. The likely importance of these activities in the overall effect of the envelope is considered.

Lipid composition of chlorophyl-protein complexes: Specific enrichment in trans-hexadecenoic acid of an oligomeric form of light-harvesting chlorophyll aa/b protein

Thylakoid membranes of higher plants and green algae can be resolved by SDS-polyacrylamide gel electrophoresis into at least 2 different chlorophyll-protein complexes and -30 polypeptides. The 2 chlorophy~-protein complexes correspond to the P700 chI a--protein complex (CPI) assumed to originate from the reaction centre of photosystem I and to the lightharvesting chl a&protein complex named LHCP or CP II [ 1 ] which is considered to represent the antenna chlorophyll of photosystem II. It is now well known that using milder conditions of solubilization, additional &l-proteins can be obtained. They correspond to a new chla-protein complex generally termed CPa, which may represent the photosystem II reaction centre complex 12-41, and to several oligomeric forms of CP 1 and LHCP f3-131. Although these different &l-protein complexes are characterized by some of their physiological, biochemical and physical properties (reviews [ 1,14--16]), little is known about their lipid composition other than pigments. The &-protein complexes were firstly considered to contain only traces of lipids [ 171. Two recent analyse? -’ -d the lipid composition of sub-

Use of zinc acetate in extract purification for aflatoxin assay of cottonseed products.

AbstractThe official Association of Official Analytical Chemists’ and American Oil Chemists’ Society’s methods for aflatoxin assay of cottonseed products utilize 20% lead acetate solution to remove gossypol, fatty acids, and traces of lipids as insoluble lead derivatives. The substitution of a 20% zinc acetate solution containing a trace of a trivalent metal chloride to precipitate zinc derivatives yields, in some cases, superior cleanup of interfering compounds of primary extracts.

Analysis of Halobacterium halobium Gas Vesicles

Gas vesicles, isolated from lysed Halobacterium halobium cells, gave an amino acid analysis which accounted for 78% of the weight, and the balance was mainly salt and water. One percent of tightly bound d-galactose was found, as well as 2% of phosphate that was not released by treatment which promotes beta-elimination, by hydrolytic release of the galactose, by carboxymethylation of lysine, or by alkaline phosphatase digestion. Only a trace of lipid was detected, and it appeared to have a polyisoprenoid structure. The vesicles were not solubilized by extremes of pH, by agents such as urea, guanidine hydrochloride, formic acid, and detergents, or by organic solvents. Succinylation and carboxymethylation gave partial dispersion, but the products were heterogeneous and of high molecular weight. The amino acid composition of vesicles was independent of fragment size. No band was obtained by polyacrylamide gel electrophoresis, with neutral, acidic, and alkaline systems, with or without sodium dodecyl sulfate and urea, before or after chemical modification. No amino terminus was detected. Electrofocusing of a vesicle dispersion showed a major component with a pI of 4.0 and an amino acid composition of the whole vesicles, and a minor band with pI 3.4 which had an amino acid composition different from whole vesicles. Vesicle protein was resistant to digestion by Pronase, trypsin, thermolysin, and papain. The precipitin reaction with rabbit antivesicle serum was not inhibited by galactose or inorganic phosphate. Succinylated and carboxymethylated vesicles cross-reacted with antivesicle serum. Cell lysates contained material which reacted with antiserum, but it was heterogeneous and mainly larger than 5 x 10(6) daltons. Material from nonvacuolated mutants reacted weakly with antiserum, but the amino acid composition of the precipitated antigen was different from that of vesicles and of soluble cross-reacting material from vacuolated cells.

Rabbit Tamm-Horsfall urinary glycoprotein. Chemical composition and subunit structure.

1. Tamm-Horsfall glycoprotein from rabbit urine has been isolated and characterized. The homogeneity of the preparation has been established by a variety of procedures including disc gel electrophoresis and ultracentrifugation in aqueous solution, sodium dodecyl sulphate and formic acid. 2. The chemical composition has been determined and a carbohydrate content of approx. 31% was obtained. The relative contents of the amino acids were shown to be very similar to those in human Tamm-Horsfall glycoprotein. A trace of lipid was also detected. 3. Leucine was identified as the only N-terminal amino acid. 4. The subunit structure was investigated in the presence of sodium dodecyl sulphate by gel filtration and disc gel electrophoresis. These studies indicated that the subunit possessed a molecular weight of approx. 84000+/-6000. A similar value was obtained after reduction and S-alkylation of the glycoprotein indicating that the disulphide bonds were all intrachain. 5. A minimum value for the chemical molecular weight of 85000+/-6000 was obtained from the number of N-terminal amino acids released by cyanogen bromide cleavage of the glycoprotein. 6. The immunological properties of the glycoprotein were studied. Cross reactivity was demonstrated between human Tamm-Horsfall glycoprotein and a guinea-pig anti-rabbit Tamm-Horsfall antiserum.

Chemical studies of the internal shell of of the slug, Ariolimax columbianus (gould) with special reference to the organic matrix

1. 1. Calcium content of the shell varies with the nutritional conditions. The primary function of this structure may be that of storing calcium. 2. 2. Histochemical and chemical tests reveal that the organic matrix is mostly protein, with small amounts of neutral and acidic mucopolysaccharides and traces of lipids. 3. 3. Hydrolytic products of the matrix include fucose, galactose and glusosamine. 4. 4. Seventeen amino acids are present in the hydrolysates of the matrix. There is less glycine than is usual in molluscan shells and aspartic and glutamic acids are abundant. 5. 5. The slug shell matrix is different from other molluscan shell matrices in its low glycine and high carbohydrate content.

The properties of the protein of the plasma membrane of ox erythrocytes

1. A method for the solubilisation of the protein of the ox erythrocyte ghost by butanol fractionation is described. The protein, as isolated, has a molecular weight of the order of 300 000, but a number of observations indicate that the preparation consists of particles of different sizes, possibly a series of aggregates of a smaller unit. In an ultracentifuge it separates into two fractions with sedimentation coefficients of 5 S and 10 S, each of which is itself heterogenous in size. 2. Electrophoresis, column chromatography and the effect of pH on solubility indicate that the protein is a sialoprotein, and, with the possible exception of some minor fractions amounting to about 10% of the total protein, no significant amount of protein free of sialic acid is detectable. Associated with the protein in the acqueous phase is a trace of lipid and about 8% by weight of carbohydrate. 3. The implications of these results to the organisation of the protein in the membrane are discussed.

Intimal proliferation and spontaneous lipid deposition in the cerebral arteries of sheep and steers

Summary Major bifurcations of cerebral arteries from sheep and steers were examined by the serial section technique (paraffin and frozen gelatin). Intimal proliferation was found at specific sites in all forks. Only a trace of lipid was found in one fork in the steers but in the sheep intimal thickenings were sites of predilection for spontaneous lipid deposition and they appear to be an integral stage in the pathogenesis of atherosclerosis.

A Morphological and Histochemical Study of the Oocytes of the Fish, Ophiocephalus punctatus, with particular Reference to Lipids

ABSTRACT The cytoplasmic inclusions of the growing oocytes of the fish, Ophiocephalus punctatus, have been studied both morphologically and histochemically. It has been observed that the non-yolky oocytes of early stages consist of granules of two types, namely the mitochondria and the lipid granules of first category (L1). The mitochondria are smaller granules, and they are found to be protein in nature with traces of lipids. The bigger granules (L1) consist of phospholipids only; they correspond to the so-called ‘Golgi bodies’ of earlier workers on fish oocytes. The yolk found in the late oocytes is of two types. The first type of yolk globules, which appear with the approach of the breeding season, consist of lipids only, and have been described as lipid bodies of the second category (L2). At first they are spheres consisting of phospholipids and triglycerides, but in the mature eggs they are transformed into big fat globules containing triglycerides only. The second type of yolk, which appears later, is in the form of spheres, rich in proteins and lipoproteins. Lastly there is ‘vacuolar yolk’, rich in carbohydrates and proteins; this develops in vacuoles.

Chemical composition of the nematode cuticle. Observations of the whole cuticle

1. (1) The following sixteen amino acids have been detected in the hydrolysed cuticles of Ascaris lumbricoides, Toxocara mystax and Strongylus equinus: glycine, alanine, valine, leucine, threonine, cystine, cysteic acid, aspartic acid, glutamic acid, lysine, arginine, histidine, tyrosine, tryptophane, proline and hydroxy-proline. 2. (2) Traces of lipid have been detected in the cuticles of Ascaris lumbricoides and Strongylus equinus. 3. (3) Traces of an aldohexose have also been detected in the hydrolysed cuticles of these two nematodes.