Plasma lipid transport in the horse (Equus caballus)

• 1.1. Equine plasma contains lipoproteins corresponding to very low density (VLDL), low density (LDL) and high density lipoproteins (HDL).
• 2.2. HDL accounts for approximately 60% of plasma lipoprotein mass and consists of a single population of particles.
• 3.3. LDL is heterogeneous comprising three discrete subfractions.
• 4.4. Two proteins are found in the region of apolipoprotein (apo) B-100 in VLDL and LDL and a third similar to apo B-48 is in VLDL.
• 5.5. Lecithin:cholesterol acyl transferase is active in plasma and hepatic lipase and lipoprotein lipase are evident in post-heparin plasma.
• 6.6. There is no significant cholesteryl ester transfer protein activity.

     

Comparison of the intravascular metabolism of cholesteryl esters and apoproteins of plasma low- and high-density lipoproteins in the rat (Rattus norvegicus), an animal species without plasma cholesteryl ester transfer activity

• 1.1. The intravascular metabolism of the cholesteryl esters (CE) and apoproteins of low density lipoproteins (LDL) and high density lipoproteins (HDL) was compared in the rat, an animal species without plasma cholesteryl ester transfer activity (CETA).
• 2.2. The apoproteins and the CE of LDL had identical catabolic rates, and there was no transfer of LDL CE to other lipoprotein classes.
• 3.3. The CE of the HDL, however, had higher catabolic rates than the apoproteins, and there was transfer of HDL CE to LDL but not to very low density lipoproteins.

     

Effect of LCAT on HDL-mediated cholesterol efflux from loaded EA.hy 926 cells

• 1.1. Human endothelial cells (EA.hy 926 line) were loaded with cholesterol, using cationized LDL, and the effect of lecithin:cholesterol acyltransferase (LCAT) on cellular cholesterol efflux mediated by high density lipoproteins (HDL) was measured subsequently.
• 2.2. In plasma, lecithin:cholesterol acyltransferase (LCAT) converts unesterified HDL cholesterol into cholesteryl esters, thereby maintaining the low UC/PL ratio of HDL. It was tested if further decrease in UC/PL ratio of HDL by LCAT influences cellular cholesterol efflux in vitro.
• 3.3. Efflux was measured as the decrease of cellular cholesterol after 24 hr of incubation with various concentrations of HDL in the presence and absence of LCAT. LCAT from human plasma (about 3000-fold purified) was added to the cell culture, resulting in activity levels in the culture media of 60–70% of human serum.
• 4.4. Although LCAT had a profound effect on HDL structure (UC/TC and UC/PL ratio's decreased), the enzyme did not enhance efflux of cellular cholesterol, using a wide range of HDL concentrations (0.05–2.00 mg HDL protein/ml).
• 5.5. The data indicate that the extremely low unesterified cholesterol content of HDL, induced by LCAT, does not enhance efflux of cholesterol from loaded EA.hy 926 cells. It is concluded that the HDL composition (as isolated from plasma by ultracentrifugation) is optimal for uptake of cellular cholesterol.

     

Serum lipoproteins of sea bass (Dicentrarchus Labrax L.). Purification and partial characterization by density gradient ultracentrifugation and agarose column chromatography

• 1.1. Five classes of sea bass serum lipoproteins were purified by single vertical spin ultracentrifugation and agarose column chromatography
• 2.2. VLDL, beta migrating, are the larger and less dense lipoproteins.
• 3.3. LDL are the more heterogeneous in size, ranging from 11 × 10⁶ to 1 × 10⁶.
• 4.4. HDL represent the predominant class which, on the basis of density and electrophoresis migration, is differentiated in three subclasses.
• 5.5. VHDL float at a density > 1.22 mg/ml, which corresponds to the density of the other serum lipoproteins. This subclass, with an apparent molecular weight of 1.5 × 10⁵, resembles the albumin-like fatty acids binding proteins, shown in mammals and teleosts and absent in elasmobranchs.

     

Effects of milk fat,unhydrogenated and partially hydrogenated vegetable oils on serum lipoproteins in growing pigs

• 1.1. Crossbred Yorkshire (Yorkshire × Landrace) pigs were fed butter oil, cream, low erucic acid rapeseed oil, sunflower oil and partially hydrogenated sunflower oil in amounts representing 30% of energy for periods of up to 13 weeks.
• 2.2. After 13 wk of feeding serum total cholesterol levels of pigs fed milk fat were significantly higher than of pigs fed vegetable oils.
• 3.3. The difference in cholesterol was mainly due to an increase in the density range of 1.063–1.125 g/ml containing pig LDL₂ and some HDL.
• 4.4. A shift towards smaller LDL particle size was apparent in pigs fed milk fat.
• 5.5. The effects of dietary trans fatty acids did not differ from cis polyunsaturated or monounsaturated fatty acids.

     

Effect of dietary coconut oil on lipoprotein composition of young chick (Gallus domesticus)

• 1.1. The composition of HDL, the major lipoprotein fraction from chick serum, drastically changed after 2 weeks of coconut oil feeding. Total cholesterol and triacylglycerols significantly increased following dietary 10 or 20% coconut oil supplementation.
• 2.2. Changes in LDL composition were less profound, cholesterol being the only component that increased by coconut oil supplementation (10 or 20%).
• 3.3. IDL proteins were the only components that increased following the same dietary treatment (20%).
• 4.4. VLDL cholesterol and proteins also increased after 1–2 weeks of 20% coconut oil supplementation to the diet.
• 5.5. Of total lipoproteins, the cholesterol content strongly increased after dietary treatment, while triacylglycerols did not change significantly.

     

Isolation of crustacean egg yolk lipoproteins by differential density gradient ultracentrifugation

• 1.1. Egg yolk lipoproteins from four species of Crustacea were isolated by differential density gradient ultracentrifugation.
• 2.2. Egg yolk proteins from freshwater prawn, striped stone crab and mitten crab consissted of high-density lipoprotein (HDL) and lipid-free protein, while low-density lipoprotein (LDL) was present in the egg yolk protein of sand crayfish as well as HDL and lipid-free protein.
• 3.3. HDL was a major component in the egg yolk proteins from four species of Crustacea. HDL was identical to egg yolk lipovitellin.
• 4.4. Both HDL and LDL possessed phospholipid as a major lipid.
• 5.5. HDL, but not LDL, contained carotenoids. The color of HDL from mitten crab showed a reddish purple and was distinct from other Crustacea whose color was orange. The reddish purple color was characterized by an absorption flexion at 600–650 nm.

     

Distribution of canthaxanthin in immature rainbow trout Oncorhynchus mykiss serum

• 1.1. The present study was undertaken in order to define the distribution of canthaxanthin between the lipoprotein fractions in serum of immature rainbow trout fed a diet supplemented with synthetic canthaxanthin (80 mg/kg).
• 2.2. Lipoproteins were separated by density-gradient ultracentrifugation.
• 3.3. Canthaxanthin was found in all lipoprotein fractions, in different amounts according to the density of the lipoprotein fraction: VLDL, 13.9%; LDL, 15.2% or LDL, 29.1% since the density of the first fraction was 1.006 g/ml; HDL, 60.4% and VHDL, 10.5%.

     

Purification and partial characterization of an AMP deaminase from the marine invertebrate Palaemon serratus

• 1.1. AMP deaminase from Palaemon serratus tail muscle was partially purified by chromatography on cellulose phosphate.
• 2.2. Muscle homogenates expressed very low enzyme activities and the presence of ATP was necessary to detect AMP deaminase. The specific activity and substrate affinity of the purified enzyme were also very low.
• 3.3. The purified prawn muscle AMP deaminase was contaminated by contractile proteins, one of the major contaminants being actin.
• 4.4. The enzyme displayed a very high affinity for actomyosin which was only partially abolished by pyrophosphate.

     

The role of lipoproteins in the delivery of tumour-targeting photosensitizers

• 1.I. Serum lipoproteins play an important role in the in vivo transport of several porphyrinoid derivatives having a moderate or high degree of hydrophobicity.
• 2.2. There appears to exist a correlation between the extent of photosensitizer association with low-density lipoproteins (LDL) and the efficiency of tumour targeting by some classes of photosensitizers, such as differently sulphonated porphyrins and phthalocyanines, haematoporphyrin dialkylethers and unsubstituted phthalocyanines and naphthalocyanines.
• 3.3. In all cases, LDL-carried photosensitizers are preferentially released to malignant cells; hence, direct cell damage appears to be the major determinant of tumour damage consequent to photodynamic therapy.
• 4.4. Present evidence suggests that the LDL-associated photosensitizer is accumulated by tumour cells largely via a receptor-mediated endocytotic process.
• 5.5. Thus, the use of delivery systems for orientating a systemically injected photosensitizer towards lipoproteins has been explored; promising results have been obtained by incorporation of the dye into liposomal vesicles, oil emulsions or inclusion complexes, as well as by precomplexation of the dye with LDL.
• 6.6. Moreover, a suitable choice of the chemical constituents of the delivery system and the experimental conditions allows one to modulate the photosensitizer distribution among the different lipoproteins.
• 7.7. The occurrence of tumour-targeting strategies other than the LDL pathway is briefly discussed.

     

Haematology of the australian eastern quoll,Dasyurus viverrinus

• 1.1. A variety of haematological parameters were determined in adult Dasyurus viverrinus.
• 2.2. Haemoglobin and red cell counts were high with a very low mean cell volume.
• 3.3. Basophils are absent but the eosinophils contain small numbers of basophilic granules which may indicate a dual role for this cell.
• 4.4. “Ring Form” leucocytes are present.
• 5.5. Three types of red cell picture could be identified, some animals showing large numbers of spherocytes, spicule cells, and inclusion bodies.
• 6.6. These cells resemble those found in some inherited human haemolytic anaemias but there was no evidence of haemolysis in the animals.
• 7.7. An alkali resistant haemoglobin component is present.

     

Mitochondrial and peroxisomal fractions derived from human white adipocytes

• 1.1. A procedure is described for the separation of intact peroxisomes from human white adipocytes using a linear metrizamide gradient (20–50% w/v).
• 2.2. Peroxisomes were found in the high density region of the gradient in an intact form.
• 3.3. Mitochondria were distributed in the high density and low density regions of the gradient.
• 4.4. Lysosomes separated well from the peroxisomes, occurring only in the low density region of the gradient.
• 5.5. Low levels of glyoxylate cycle enzyme activities (isocitrate lyase and malate synthase) were detected within the light and heavy mitochondrial pellet fractions.

     

Identification of cathepsin L-like proteinase and aminopeptidase in yolk granules of the sand worm,Nereis diversicolor

• 1.1. Two proteinases have been identified in yolk granules of Nereis diversicolor mature oocytes, an aminopeptidase and an acid cysteine proteinase.
• 2.2. The aminopeptidase was identified as a metallo-enzyme having a molecular weight of about 260 kDa.
• 3.3. Except that the acid cysteine proteinase is a high molecular weight protein (200 kDa) and has a very low pH optimum (3.0), the enzyme possesses properties resembling those of mammalian cathepsin L.
• 4.4. The cathepsin L-like proteinase was found to be liable to the in vitro proteolysis of the yolk granule proteins and is therefore suggested to be involved in yolk protein processing.

     

Isolation of dna and rna from Streptococcus sobrinus OMZ176 using CsTFA gradients

• 1.1. A simple procedure for isolation of high molecular weight genomic DNA, and RNA, from Streptococcus sobrinus OMZ176 is described.
• 2.2. Cell cultures were grown aerobically for 10 hr.
• 3.3. Spheroplast formation and lysis was achieved by mutanolysin/lysozyme-dependent digestion of the cell wall, followed by N-lauroylsarcosinate-mediated lysis.
• 4.4. Nucleic acids were isolated directly from cell-lysates using cesium-trifluoroacetate (CsTFA) densitygradient centrifugation.
• 5.5. Three different centrifugation regimes were tested: self-generated density gradients in a fixed angle rotor; self-generated density-gradients in a swinging-bucket rotor; pre-formed density-gradients in a swinging-bucket rotor.
• 6.6. Genomic DNA isolated by the CsTFA-procedure was found to have higher purity as compared to genomic DNA isolated in a conventional CsCl gradient.
• 7.7. Isolated DNA was shown to be of a quality suitable for applications in molecular biology.

     

The interaction of human serum albumin in the native and fully reduced states with apolipoprotein E,serum amiloid protein and very low density lipoproteins from human plasma

• 1.1. Complex formation in a solution of apolipoprotein E (apoE) isolated from human plasma very low density lipoproteins (VLDL) and human serum albumin (HSA) in both native and fully reduced states was studied. The existence of a kinetically unstable complex of apoE and native albumin was shown. The complex became more stable with the reduction of the S—S links in the albumin molecules capable of forming aggregates under these conditions.
• 2.2. The interaction between native HSA as opposed to a fully reduced one and isolated VLDL particles was more pronounced, probably, due to the existence of amphipathic alpha-helical regions.
• 3.3. Dissociation of the serum amyloid protein (SAP) oligomeric form in solution and the interaction of the protein with fully reduced HSA owing to the provision with the additional hydrophobic surface was shown. ApoE displaced SAP from the complex with fully reduced albumin.
• 4.4. It is suggested that the ability of the apolipoprotein to interact with albumin is determined by internal stability of the molecular structure of the latter and the complexes detected in vitro may be a new transport form of apolipoproteins in lipid-free form in serum. It is assumed that competitive interactions in the HSA-SAP-apoE system may be involved in the development of secondary amyloidosis.

     

Cholesterol metabolism in new world primates: Comparative studies in two tamarin species (Saguinus oedipus and Saguinus fuscicollis) and the squirrel monkey (Saimiri sciureus)

• 1.1. Cholesterol metabolism has been characterized in three species of New World primates, the cotton-top tamarin, the saddle-back tamarin, and the squirrel monkey.
• 2.2. When fed a diet containing cholesterol, the three species exhibited differing responses of plasma cholesterol levels.
• 3.3. Dietary cholesterol absorption was determined and plasma cholesterol die-away kinetics were analyzed in terms of a two-pool model.
• 4.4. The results of the analyses of cholesterol turnover are consistent with the observed species-specific differences in plasma cholesterol values and cholesterol absorption.
• 5.5. Cholesterol metabolism differs between the two tamarin species, as well as between the tamarins and the squirrel monkey.
• 6.6. Implications of species-specific differences between tamarin species are discussed in terms of the use of tamarin species as animal models for comparative studies of cholesterol metabolism and the etiology of cancer and cardiovascular disease.

     

Bovine aorta contains at least two related forms of heparan sulphate proteoglycan

• 1.1. The proteoglycan peak from anion exchange chromatography of an extract of bovine aorta was digested with chondroitinase ABC. The residual heparan sulphate proteoglycans were further purified by chromatography on Sepharose CL4B and DEAE-Sephacel to yield two species, of high and low charge density.
• 2.2. Higher molecular weight material had a higher proportion of high charge density proteoglycan, while the lower molecular weight species had a higher proportion of low charge density heparan sulphate proteoglycan.
• 3.3. The two species shared epitopes as they both reacted with an antibody to heparan sulphate proteoglycan from bovine glomerular basement membrane.
• 4.4. On electron microscopy, both high and low charge density proteoglycans were visualized as ‘tadpole-like’ molecules, which showed a tendency to aggregate via their globular heads.
• 5.5. Bovine aortic smooth muscle cells were cultured in the presence of [³⁵S]sulphate and [³H]glucosamine. Proteoglycans were isolated from medium and cell layer extract by the methods outlined above.
• 6.6. The major HSPG species isolated from medium were significantly larger than those from cell layer and displayed substantial heterogeneity in both size of HS chain after papain digestion and size of protein core after heparitinase digestion. 7. The major cell layer species yielded two HS species of widely differing mol. wt after papain digestion, and a very small protein core after heparitinase digestion. Therefore cell layer-associated HSPGs show a good deal more homogeneity than those found in the medium.
• 7.8. Further ion-exchange chromatography after digestion with chondroitinase ABC revealed HSPG species of lower charge density, possibly derived from a hybrid chondroitin sulphate-dermatan sulphate proteoglycan (CS/DSPG) after removal of the CS/DS chains.

     

Investigation of phycocyanin-membrane interaction: Promotion of membrane interactions

• 1.1. In a continuing investigation of phycocyanin-membrane surface interaction, fluorescence quenching experiments were performed with a mixture of two populations of fluorescence probe-encapsulated phospholipid bilayer vesicles in the presence and absence of phycocyanin.
• 2.2. These membrane vesicles were prepared with 1,2-dimyristoyl phosphatidylcholine (DMPC), cholesterol and a probe molecule.
• 3.3. A fluorophore was encapsulated in one population of membrane vesicles, while a quencher was encapsulated in another population of membrane vesicles.
• 4.4. The result was compared with those of experiments in the presence of other biomolecules, including albumin, cytochrome c, hemoglobin, myoglobin or RNA.
• 5.5. Interestingly, a one-third reduction of the fluorescence intensity was observed in the mixture of these two populations of membrane vesicles in phycocyanin's presence.
• 6.6. In contrast, the other biomolecules caused no significant reduction in the fluorescence intensity.
• 7.7. These findings were evidence of a phycocyanin-induced membrane perturbation.
• 8.8. This was further demonstrated by a phycocyanin-induced change in the thermotropic behavior of DMPC vesicles, as measured by differential scanning microcalorimetry.
• 9.9. Such a unique property of phycocyanin is believed to be associated with its known membrane surface-interacting character.
• 10.10. A possible phycocyanin-modulated membrane-membrane interaction was discussed.

     

Hematology and blood chemistry of the marsh harrier (Circus aeruginosus)

• 1.1. This study deals with the hematological and blood chemistry of 13 adult marsh harriers (Circus aeruginosus).
• 2.2. No significant differences were observed between male and female groups in any of the parameters.
• 3.3. The value of white blood cells was 14,677/mm³ heterophils and lymphocytes, these being the most abundant cellular type (81.42 and 12%, respectively).
• 4.4. Urea and uric acid are present in approximately similar proportions, though birds are said to be uricotelic.
• 5.5. The cholesterol concentration values determined in our study, are higher than those reported in most other birds.

     

Correlation between body color and behavior in the upside-down catfish,Synodontis nigriventris

• 1.1. Unlike common fishes and as its Latin name implies, the upside-down catfish, Synodontis nigriventris, possesses dark ventral skin. Microscopic observation reveals that melanophores are present on both the ventral and the dorsal skin but differ in size and density of distribution.
• 2.2. The darkness of both sides of the fish changes in accordance with that of the background.
• 3.3. At night, the fish are very active and the body becomes pale. The change in color is more noticeable in the dorsal than the ventral skin.
• 4.4. When melatonin was added to the bathing water, the fish became pale and swam restlessly even when they were exposed to the black background.
• 5.5. It was found that the catfish preferred the black background to the white one.