bluuebunny/crossref_metadata_2025 huggingface dataset:
The metabolism of polyunsaturated fatty acids in rat sertoli and germinal cells
Authors: Beckman J. K. , Coniglio J. G.
Published: November 2006

The metabolism of [1‐14C]linoleic, [1‐14C]arachidonic and [3‐14C]docosa‐4,7,10,13,16‐pentaenoic acids was investigated after intratesticular injection of the labeled compounds and isolation of rat Sertoli and germinal cells. Following injection of either14C‐linoleate or14C‐arachidonate, the specific activity (sp act) of docosa‐4,7,10,13,16‐pentaenoic acid of Sertoli cells was greater than that of the germinal cells. The data suggest that the Sertoli cells are more active in the biosynthesis of the 22‐carbon pentaene than the germinal cells. Differences between these 2 cell types were also noted in the distribution of the incorporated14C among the various lipid classes. Following intratesticular injection of14C‐docosapentaenoic acid, a greater proportion of the recovered14C in Sertoli cells than in germinal cells was present in 20‐carbon fatty acids, suggesting a greater activity in Sertoli cells in the metabolism of the pentaene. The major portion of the recovered14C in both cell types was present in triacylglycerols during early time periods and in phospholipids after 24 hr. The possibility of transfer of biosynthesized docosapentaenoic acid from Sertoli to germinal cells is discussed.
Effect of plant sterols, fatty acids and lecithin on cholesterol absorption in vivo in the rat
Authors: Hollander Daniel , Morgan Donna
Published: November 2006

The inhibitory effect of plant sterols, fatty acids and lecithin on cholesterol intestnal absorption was studied in the unanesthetized rat using a single pass perfusion technique. Bile was excluded from the perfused intestine. Cholesterol absorption did not change following the additions of cholestanol, cholestanone, lanosterol, stigmasterol and β‐sitosterol. A 3‐fold increase in the molarity of cholestanol and β‐sitosterol or the separate additions of the saturated short and medium chain fatty acids, butyric and octanoic, also did not change cholesterol absorption. The unsaturated long chain fatty acids, oleic, linoleic, linolenic and arachidonic, inhibited cholesterol absorption. Lecithin additions at concentrations of 0.1–1.5 mM caused a progressive, dose‐related inhibition of cholesterol absorption. The inhibitory effect of these agents on cholesterol absorption is likely to have been caused by changes in cholesterol solubility in the micelle and shifts in the partition coefficient of cholesterol away from the cell membrane to the micelle.
Distribution of the phosphatidate phosphohydrolase activity in the lamellar body and lysosomal fractions of lung tissue
Authors: Okazaki Takeshi , Johnston John M.
Published: November 2006

Phosphatidate phosphohydrolase (PAPase) activity was measured in lamellar bodies purified from porcine lung tissue. After repeated freeze‐thawing, only a negligible amount of PAPase activity was released into the soluble fractions, whereas there was release of 2 lysosomal marker enzyme activities, glucosaminidase and β‐galactosidase into the soluble fraction. In addition, a lysosomal‐enriched fraction was prepared from adult rat lung tissue by prior treatment of the rats with Triton WR 1339. Treatment with Triton WR 1339 resulted in the significant shift of the activities of the lysosomal marker enzymes, glucosaminidase and β‐galactosidase, to less dense subcellular fractions. The highest specific activity of PAPase was found in a subcellular fraction which had a density that was intermediate between that of the mitochondrial and microsomal fractions and the distribution of PAPase activity was not affected by the prior treatment of the rats with Triton WR 1339.
The structure of plasma low density lipoproteins: Experimental facts and interpretations—A minireview
Authors: Kirchhausen Tomas , Fless Gunther , Scanu Angelo M.
Published: November 2006

From data on size and chemical composition, low density lipoprotein (LDL) can be described as a spherical particle having cholesteryl esters and triglycerides contained in a spherical core covered by the closely packed hydrophobic ends of phospholipids and unesterified cholesterol, while the head groups of the phospholipids, together with protein, occupy the surface. Such a model is compatible with early small angle X‐ray and neutron scattering studies which, by postulating spherical symmetry, assigned the LDL constituents to locations predicted from the radial electron density distribution. However, the concept of spherical symmetry, as applied to LDL structure, was recently challenged by results obtained from freeze‐etching electron microscopy and small angle X‐ray scattering experiments. Novel interpretations of these data suggest that the surface of LDL contains 4 electron‐dense globules, located at tetrahedral positions, which have a capacity for structural remodeling at least as a function of the 2 temperatures studied (21C and 41C). It is reasonable to presume that the LDL protein (apo LDL) plays a role in the organization of the surface and overall LDL structure. However, until the chemical properties of apo LDL, and its behavior in solution and at the water‐lipid interface are better understood, the validity of the proposed models cannot be assessed.
Alkenyl and alkyl ether phospholipids in pig mesenteric lymph node lymphocytes
Authors: Sugiura Takayuki , Masuzawa Yasuo , Waku Keizo
Published: November 2006

Significant amounts of alkenyl and alkyl ether phosphoglycerides were found in pig mesenteric lymph node lymphocytes. The choline phosphoglycerides are composed of 2.6% alkenyl ether and 25.7% alkyl ether compounds besides 71.7% diacyl analogs. The ethanolamine phosphoglycerides consist of 50.2% alkenyl ether, 7.8% alkyl ether and 42.0% diacyl compounds. The fatty chain compositions at the 1‐ and 2‐positions of each lipid class were analyzed.
Distribution of phosphoinositides among subfractions of rat brain myelin
Authors: Deshmukh D. S. , Kuizon S. , Bear W. D. , Brockerhoff H.
Published: November 2006

Rat brain myelin was separated into three subfractions, heavy, medium, and light, and the concentrations of phosphatidic acids (PA), phosphatidylinositol (PI), di‐ (DPI), and triphosphoinositide (TPI) in these fractions were determined. PI was evenly distributed among the fractions, and PA, DPI, and TPI occurred in highest concentrations in the “light” myelin. This result indicates that these fast metabolizing lipids play an important role in the tightly packed central lamellae of the myelin sheath.
Microsomal phosphatidic acid phosphohydrolase of rat mammary tissue: I. General properties
Authors: Tanaka K. , Kinsella J. E.
Published: November 2006

The microsomal bound phosphatidic acid phosphohydrolase from lactating rat mammary tissue had a specific activity of six nmoles per mg protein per minute. The optimum pH was 7.0; magnesium at 1.3 mM was required for maximum activity, and at low substrate concentrations magnesium lowered the Km of the enzyme for phosphatidic acid. Diglycerides exerted little effect while diglyceride ether stimulated enzyme activity. Inorganic salts, i.e., potassium phosphate and potassium chloride, enhanced rates of phosphatidic acid hydrolysis under standard assay conditions.
Identification of lipoxygenase‐linoleate decomposition products by direct gas chromatography‐mass spectrometry
Authors: St. Angelo A. J. , Legendre M. G. , Dupuy H. P.
Published: November 2006

Lipoxygenase, prepared from Virginia‐type peanuts, was used to catalyze the oxidation of linoleic acid and methyl linoleate to form the C−9 and C−13 hydroperoxides. These reactions were monitored by rapid unconventional direct gas chromatography‐mass spectroscopy. An aliquot of the enzymatic reaction mixture, without prior extraction or chemical modification, was secured directly into the heated (40–70 C) or nonheated (room temperature) injection system. When the reaction mixture was analyzed at room temperature, only hexanal was found. At elevated temperatures, five major and several minor components were identified. The predominant compounds identified were pentane, hexanal, 2‐pentylfuran,trans‐2,cis‐4‐decadienal, andtrans‐2,trans‐4‐decadienal. These products originate from decomposition of either the C−9 or C−13 hydroperoxides generated by peanut lipoxygenase.
Sterol composition of nystatin and amphotericin B resistant tobacco calluses
Authors: Chiu Pei‐Lu , Bottino P. J. , Patterson G. W.
Published: November 2006

The objective of this study was to select and characterize tobacco cell lines resistant to the polyene antibiotics Amphotericin B and Nystatin. Suspension culture cells of tobacco (Nicotiana tabacum L. ‘Wisconsin 38’) were treated with 0.025% ethyl methane sulfonate (EMS) and suspended in melted agar medium containing 0.005 mg/ml Amphotericin B. Cells were also irradiated with UV from a germicidal lamp and plated in the melted agar plating medium. After 6–10 days growth, the cultures were overplated with medium containing 750 u/ml Nystatin. All cultures were grown at 26 C in the dark. After three weeks, a single callus was isolated from the Amphotericin B treatment. This callus was subcultured, and would grow at concentrations of the antibiotic as high as 0.1 mg/ml (a 20‐fold increase over the selection concentration). Six callus lines were isolated from the Nystatin treatment. After subculture and transfer to media containing higher concentrations of Nystatin, only two calli survived and would grow at 1250 u/uml. Gas liquid chromatographic analysis of the resistant and control callus lines revealed similar sterol content among all the lines. However, when comparing total sterols produced, all three polyene resistant calluses contained significantly more sterols than the control. The Amphotericin B resistant calli produced about three times as much sterol as the controls, and the Nystatin resistant calli produced about 1.5 times as much sterol as the control. Both Nystatin resistant lines showed significant increases in stigmasterol. It appears that resistance of the three tobacco cell lines to these polyene antibiotics is due principally to varied amounts of overproduction of sterols rather than qualitative differences in sterols.
Effect of low methionine, choline deficient diets upon major unsaturated phosphatidyl choline fractions of rat liver and plasma
Authors: Lyman R. L. , Giotas C. , Medwadowski B. , Miljanich P.
Published: November 2006

To see how the metabolism of specific phosphatidyl choline fractions might be affected when only a limited source of methyl groups was available, rats were fed for 7 days a low methionine, cholinedeficient diet or one supplemented with either choline or methionine. Prior to killing, they were injected with14C‐methyl methionine and liver and plasma phosphatidyl choline isolated and separated by argentation chromatography into 3 major unsaturated fractions. Fatty acid composition and radioactivity of the fractions were determined. Deficient rats had reduced total liver phosphatidyl choline when compared with the supplemented groups, but the proportions of 20∶4 and 22∶6 fatty acids in the total phosphatidyl choline were unchanged. Plasma phosphatidyl choline also was reduced sharply by the deficiency, as was its proportion of 20∶4 fatty acid. Specific activities of the liver 22∶6, 20∶4, and 18∶2 phosphatidyl choline fractions showed that deficient rats had less radioactivity in their 20∶4 and 18∶2 phosphatidyl choline than did the supplemented animals. Plasma phosphatidyl choline fractions presented a similar pattern. Feeding methionine or choline nearly doubled radioactive methyl group incorporation into the 20∶4 phosphatidyl choline fraction of liver and plasma, while incorporation into the 22∶6 phosphatidyl choline was reduced or unchanged. The results suggested that, in the rat, limited availability of methyl groups altered the metabolism of liver and plasma phosphatidyl choline fractions. Methionine, as a source of labile methyl groups, appears necessary for the normal synthesis of certain unsaturated phosphatidyl choline fractions (particularly 20∶4 phosphatidyl choline). Transmethylation of phosphatidyl ethanolamine molecular species to the corresponding phosphatidyl choline species may be an important reaction in normal lipid metabolism and transport. Relative affinities for incorporation of the labeled methyl groups into the phosphatidyl choline fractions of either deficient or supplemented rats were: 22∶6>20∶4>18∶2.
Lipids of cultured hepatoma cells: VI. Glycerolipid and monoenoic fatty acid biosynthesis in minimal deviation hepatoma 7288C
Authors: Wiegand Rex D. , Wood Randall
Published: November 2006

1‐14C‐Acetic, 1‐14C‐palmitic, or 1‐14C‐stearic acid was incubated with minimal deviation hepatoma 7288C cells grown in culture to assess: de novo fatty acid synthesis, oxidation, desaturation, and elongation of saturated fatty acids, as well as the ability of media fatty acids to serve as precursors of cellular glycerolipids. Distribution of radioactivity in the individual lipid classes and the various fatty acids of triglyceride, phosphatidyl choline, and phosphatidyl ethanolamine was determined. The radioactivity among the monoenoic acid isomers derived from triglyceride, phosphatidyl choline, and phosphatidyl ethanolamine was analyzed by reductive ozonolysis. Only small amounts of the labeled substrates were oxidized to carbon dioxide. Except for labeled stearic acid, which also was incorporated heavily into phosphatidyl inositol and phosphatidyl serine, most radioactivity was recovered in triglyceride, phosphatidyl choline, and phosphatidyl ethanolamine. Synthesis of cholesterol and long chain fatty acids from labeled acetic acid demonstrated that these cells can perform de novo synthesis of fatty acids and cholesterol. Both labeled palmitic and stearic acids were desaturated to the corresponding Δ9 monoenes, and palmitic and palmitoleic acids were elongated. The hexadecenoic acid fraction isolated from triglyceride, phosphatidyl choline, and phosphatidyl ethanolamine, when acetic or palmitic acid was the labeled substrate, showed that greater than 70% of the labeled acids were the Δ9 isomer. Radioactivity of the octadecenoic acid fraction derived from labeled acetic or palmitic acids was nearly equally divided between the Δ9 isomer, oleic acid, and the Δ11 isomer, vaccenic acid. Desaturation of labeled stearic acid produced only oleic acid. These data demonstrate that the biosynthesis of vaccenic acid in these cultured neoplastic cells proceeds via the elongation of palmitoleic acid. The relatively high level of vaccenic acid synthesis in these cells suggests that the reported elevation of “oleic acid” in many neoplasms may result from increased concentration of vaccenic acid.
Glycosphingolipids of fetal and adult sheep colonic mucosa
Authors: Dahiya Rajvir , Brasitus Thomas A.
Published: November 2006

The ganglioside and neutral glycosphingolipid composition of fetal and adult sheep colonic mucosa were characterized and compared. Mono‐ and tetrahexosylceramide were the major neutral glycolipids of both fetal and adult colons. Adult, but not fetal, mucosa also possessed di‐ and trihexosylceramide. Similarly, GD1a, GM3 and GM2 were found to be the principal gangliosides in fetal and adult tissue. Adult colonic mucosa possessed significant amounts of GT1a not present in fetal tissue.

Analysis of the hydroxy and nonhydroxyfatty acids as well as of the long chain bases of the major glycosphingolipids revealed differences between these lipophilic components of glycolipids in fetal and adult colonic mucosa. The present results, therefore, indicate that both quantitative and qualitative differences in glycosphingolipid composition exist between fetal and adult sheep colonic mucosa.
Differential effects of lipoxygenase products on FMLP and LTB4 evoked neutrophil aggregation
Authors: Beckman Jeffrey K. , Gay James C. , Brash Alan R. , Lukens John N. , Oates John A.
Published: November 2006

There is evidence that the endogenous biosynthesis of LTB4 is involved in the aggregation of human neutrophils induced by the chemotactic peptide f‐met‐leu‐phe (FMLP). If LTB4 mediates this aggregatory response, then agents which desensitize neutrophils to LTB4 should inhibit the cellular response to FMLP. Since many lipoxygenase products modulate other neutrophil responses to LTB4 and FMLP, we have investigated the effects of lipoxygenase products on LTB4‐ and FMLP‐initiated aggregation.

Prior exposure to low concentrations of LTB4 (0.5–10nM) inhibited subsequent aggregation to the same agent (50nM), but it did not influence the response to FMLP (10−7 M). Relatively high concentrations of 5‐HETE (5–50μM) inhibited aggregation initiated by either stimulus. Although the hydroperoxy derivative 5‐HPETE also inhibited the response to LTB4, in the relatively narrow concentration range of 1–4μM it stimulated FMLP‐induced aggregation. This latter effect was confirmed using 12 cell preparations from six separate donors; it (the activity of 5‐HPETE) was not mimicked by other 5‐lipoxygenase products, including LTB4, nor the dihydroperoxide 8,15‐DiHPETE. Our results indicate that neutrophil aggregation in response to LTB4 or FMLP can be selectively potentiated or inhibited. On the basis of these data we conclude that the endogenous synthesis of LTB4 is not directly involved in the neutrophil aggregatory response to FMLP, although the hydroperoxy intermediate 5‐HPETE may act to enhance the cellular response.
Elongation systems involved in the biosynthesis of erucic acid from oleic acid in developingBrassica juncea seeds
Authors: Agrawal Vishwanath P. , Stumpf Paul K.
Published: November 2006

In the presence of NADPH and malonyl‐CoA, the cell‐free extract of developingBrassica juncea seeds catalyzes the elongation of14C‐oleoyl‐CoA to radioactive C20∶1 and C22∶1. The elongation of C18∶1 to C20∶1 shows no marked preference for NADPH or NADH. On the other hand, the elongation of C20∶1 to C22∶1 exhibits a pronounced preference for NADPH. Moreover, the latter elongation system (C20∶1→C22∶1) is more sensitive to inhibition by trichloroacetate and sodium metabisulfite. Inclusion of polyvinylpolypyrrolidone in the grinding buffer for preparation of the cell‐free extract enhances the elongation activity by 5–6 fold.14C‐Stearoyl‐CoA, but not14C‐palmitoyl‐CoA, also is elongated by this system. The results presented here suggest certain degrees of dissimilarity between the first (C18∶1→C20∶1) and second elongation (C20∶1→C22∶1) systems.
Modification of alkenyl chain profile in plasmalogens of rat heart mitochondria by dietary trielaidin
Authors: Wolff Robert L. , Combe Nicole A. , Entressangles Bernard
Published: November 2006

Effects of dietary trielaidin upon the alkenyl chain profile of plasmalogens were studied using heart mitochondria of rats fed a semi‐purified diet containing 10% of fat supplement in which elaidic acid accounted for 69% of total fatty acids. Alkyl substituted dioxane (ASD) derivatives of the alkenyl groups of plasmalogens were prepared and analyzed by silver nitrate TLC and by GLC on different phases (BDS and OV‐275). After two months of feeding the experimental diet, 40% of the ASD contained atrans‐octadecenyl chain, suggesting that dietary elaidic acid was reduced in vivo to the corresponding alcohol and incorporated into plasmalogens. There was a simultaneous decrease in the percentage of ASD containing saturated chains, but the percentage of ASD substituted withcis‐octadecenyl chains was not significantly affected. These observations suggested that elaidic acid may compete with saturated fatty acids, but not withcis‐octadecenoic acids during the plasmalogen biosynthesis. Feeding trielaidin did not seem to have any significant influence on the relative proportions of plasmalogens, which accounted for 11–12%, on a phosphorus basis, of total heart mitochondria phospholipids.
Inhibition of acyl CoA: Cholesterol acyltransferase and sterologenesis in rat liver by diazepam,In vitro
Authors: Bell Frank P.
Published: November 2006

Diazepam, a commonly prescribed tranquilizer, was found to inhibit cholesterol biosynthesis in rat liver minces; inhibition appeared to occur at multiple post‐mevalonate sites. Diazepam also inhibited cholesterol esterification by acylCoA:cholesterol acyltransferase in isolated liver microsomes and minces. Liver minces incubated with [14C] oleate demonstrated increased uptake of the fatty acid and a greater incorporation of the substrate into triglycerides, diglycerides and phospholipids when diazepam was present. The results suggest possible mechanisms for the hypocholesterolemic effect of diazepam in experimental animals and for the elevation of triglycerides and very low‐density lipoproteins in man and the rat.
Effect of KCD‐232, a new hypolipidemic agent, on serum lipoprotein changes in hepatoma‐bearing rats
Authors: Irikura T. , Takagi K. , Okada K. , Yagasaki K.
Published: November 2006

Changes in serum lipoprotein profiles were characterized in Donryu rats subcutaneously implanted with an ascites hepatoma line of AH109A cells and the effect of a new hypolipidemic agent with a structure of 4‐(4′‐chlorobenzyloxy)benzyl nicotinate (KCD‐232) was estimated. With the growth of hepatoma for periods of up to three weeks, a striking decrease in the high density lipoprotein (HDL) fraction and an enormous increase in the VLDL+LDL (very low density lipoprotein+low density lipoprotein) fraction were found in hepatoma‐bearing rats when either precipitation method or electrophoresis was used. These lipoprotein profiles were not influenced by sex. Judging from the electrophoretogram, the increase in VLDL+LDL fraction was due mainly to an increase in LDL fraction. The oral administration of KCD‐232 significantly suppressed the hepatoma‐induced increase in VLDL+LDL with little or no influence on the hepatoma‐induced decrease in HDL. There existed a positive correlation between the hepatoma weight and (VLDL+LDL)‐cholesterol concentration and a negative one between hepatoma and HDL‐cholesterol.
Biosynthesis of lipids by bovine meibomian glands
Authors: Kolattukudy P. E. , Rogers Linda M. , Nicolaides Nicholas
Published: November 2006

Isolated bovine meibomian glands incorporated exogenous [1‐14C] acetate into lipids. Thin layer chromatographic analysis of the lipids showed that wax esters and sterol esters contained 61% of the total label. Radio gas liquid chromatographic analysis of the acid and alcohol moieties of both ester fractions showed the label was distributed equally between the two portions of the ester in both cases. Cholesterol and 5‐α‐cholest‐7‐en‐3β‐ol were the major labeled sterols, and anteiso‐C25, anteiso‐C27 and anteiso‐C23 were the most highly labeled alcohols. The major labeled fatty acids in the wax esters were anteiso‐C15,n‐C16, anteiso‐C17 andn‐C18∶1, whereas anteiso‐C25 and anteiso‐C27 were the major labeled acids in the sterol esters. The diester region with 6% of the total label contained labeled fatty acids and fatty alcohols each with anteiso‐C25 as the major component and ω‐hydroxy acids in whichn‐C32∶1 was the major labeled component. The trigly ceride fraction which contained 8% of the total lipids was composed of labeled fatty acids similar to those found in both sterol and wax ester fractions. Chromatographic analyses of the labeled lipids derived from exogenous labeled isoleucine showed that anteiso‐branched products were preferentially labeled. The labeled triglyceride fraction derived from [U‐14C] isoleucine also contained esterified C15, C13, C11, C9, C7 and possibly shorter anteisobranched acids.
Decreased phosphatidylcholine in the lung fluid of patients with sarcoidosis
Authors: Baughman Robert P. , Strohofer Susan , Dohn Michael
Published: November 2006

Surfactant decreases the immune response of lymphocytes. Pulmonary sarcoidosis is a disease characterized by an increased number and activity of lymphocytes in the lung. We measured the lipids and lymphocytes retrieved from the lung by bronchoalveolar lavage. Thirteen patients with active pulmonary sarcoidosis had a significantly higher percentage of lymphocytes (18±21%, mean ± standard error of the mean) than 10 control subjects (4±1.9%, p<0.01). Using an external marker, we found the absolute amount of disaturated phosphatidylcholine to be higher in the control group (174±17.4 μg/ml lung fluid) than in the sarcoid group (91±1.9 μg/ml of lung fluid, p<0.002).
New natural 2‐acetoxy fatty acids using chemical ionization and electron impact mass spectrometry
Authors: Ayanoglu Eser , Kurtz Kara , Kornprobst J. M. , Djerassi Carl
Published: November 2006

The phospholipids of the spongePolymastia gleneni contain saturated long chain (C22–30)‐acetoxy fatty acids. Their structures were assigned based on chromatographic and spectrometric data as well as comparison with a synthetic sample. The use of capillary gas chromatography combined with chemical ionization and electron impact mass spectrometry was instrumental in the eludication of structures, since only a very small amount of crude lipids was available.
Influence of dietary cholesterol on the relative synthesis of hepatic glycerides and molecular classes of 1,2‐diglycerides and phospholipids in the gerbil in vivo
Authors: Andersen D. B. , Holub B. J.
Published: November 2006

The influence of dietary cholesterol on the relative rates of synthesis of hepatic lipids in the male Mongolian gerbil,Meriones unguiculatus, was studied. The semi‐purified starch‐based diet used lard as the dietary fat and was fed with or without a 0.5% (by wt.) cholesterol supplement. Each animal received 300 μCi [2‐3H]‐glycerol i.p. after 3 or 7 days on the dietary regimens. Relative rates of [2‐3H]‐glycerol incorporation into the major hepatic glycerides in vivo was not affected significantly by dietary cholesterol (0.5% level), suggesting that alteration in the relative biosynthesis of these lipids could not readily account for the higher triglyceride (TG) to phospholipid (PL) mass ratio in liver with cholesterol feeding. However, there was evidence for an increased formation of 1,2‐diglyceride (1,2‐DG). The complement of molecular species of hepatic 1,2‐DG, phosphatidylcholine (PC), and phosphatidylethanolamine (PE) formed de novo, as measured using isotopic glycerol, was not influenced greatly by dietary cholesterol, although lower mean rates of synthesis of tetraenoic relative to dienoic species of phospholipids were indicated in cholesterol‐fed gerbils.
Red pigment‐forming substances from autoxidized linolenate: Identification of prostaglandin‐like substances
Authors: Nakamura Takashi
Published: November 2006

The chemical structures of lipid degradation products capable of reacting with amino acids and forming red pigments were investigated. The red pigment‐forming substances (RPS's) derived from autoxidized linolenate in triglyceride of linseed oil were purified successively by gel chromatography on Sephadex LH‐20, column chromatography and TLC on Silica gel 60, and HPLC on μ‐Porasil. Consequently, three types of RPS's were isolated.

IR spectra of RPS's were similar, except for slight differences in the fingerprint region (1300—650 cm−1). These substances included the OH group (3500 cm−1 region), conjugated aldehyde (νC=0 1688 cm−1, νC=C 1635 cm−1) and ketone (νC=0 1740 cm−1) in their molecules. RPS's were analyzed by GLC and GC‐MS after derivatization with dimethylhydrazine and/or trimethylsilyl reagents, before and after the reduction with NaBH4 and/or hydrogenation with PtO2. The fragmentation patterns indicated the presence of an ethyl group in addition to the functional groups described above, and the molecular formula was estimated to be C10H14O3. Further elucidation of the structures was obtained by13C‐ and1H‐NMR analyses, and evidence was obtained for the presence of a hydroxypentanone ring, a PG‐like structure. The sequence of the protons on the ring carbons was unequivocally deduced from the double resonance experiments.

All the data taken together suggested that the RPS's were the stereoisomer of 3‐(2‐ethyl‐5‐hydroxy‐3‐oxo) cyclopentanyl‐2‐propenal.
Relationship between platelet cyclooxygenase pathway and plasma malondialdehyde‐like material
Authors: Violi F. , Ghiselli A. , Alessandri C. , Iuliano L. , Cordova C. , Baslano F.
Published: November 2006

Thrombin‐induced platelet malondialdehyde (MDA) formation and plasma malondialdehyde‐like material (MDA‐LM) were evaluated in 12 healthy subjects before and after 1 and 7 days from aspirin (1 g) ingestion. 24 hr after aspirin administration, platelet MDA was almost abolished while MDA‐LM showed a 23% decrease. Platelet MDA and plasma MDA‐LM returned to baseline values 7 days after aspirin ingestion. These data suggest that platelet cyclooxygenase pathway affects only in part plasma MDA‐LM. The evaluation of plasma MDA‐LM before and after aspirin could be useful for evaluating in vivo platelet cyclooxygenase activation.
Increased arachidonate incorporation in perfused heart phospholipids from vitamin E‐deficient rats
Authors: Chan Alvin C. , Fragiskos Bill , Douglas Cheryl E. , Choy Patrick C.
Published: November 2006

When perfused with exogenous arachidonic acid (AA), the rat heart incorporates this eicosanoid precursor into the phospholipids. The incorporation of AA into phosphatidylcholine was 6‐fold higher than the incorporation of AA into phosphatidylethanolamine When vitamin E‐deficient rat hearts were perfused with AA, there was a marked increase in incorporation of AA into both phosphatidylcholine and phosphatidylethanolamine compared to rats fed with a vitamin E supplemented diet. The result of this study suggests that vitamin E has a regulatory role in phospholipid biosynthesis in the mammalian heart.
Gamma linolenic acid attenuates cardiovascular responses to stress in borderline hypertensive rats
Authors: Mills David E. , Summers Maureen R. , Ward Ron P.
Published: November 2006

The purpose of the present study was to investigate the effects of gamma linolenic acid (GLA) on cardiovascular responses to psychosocial stress (isolation) and to pressor hormones in the genetically borderline hypertensive rat (SHR×WKY). Adult male SHR×WKY were divided into two groups following five weeks of group housing. One group (GLA) received eight weeks constant flow osmotic pumps releasing 0.04 mg GLA in olive oil/kg‐hr, while the second group received dummy pumps (DUM). One week following pump implantation, each group was divided into two subgroups and exposed to a four‐week experimental period of either continued group housing (no stress) or isolation (stress). A two‐week recovery period of group housing followed the experimental period. Blood pressure and heart rate were determined weekly by the tail cuff technique. At the end of the recovery period, animals in the no stress condition were anesthetized and received an arterial cannula for NOR and ANG infusion and direct BP recording. Then the responses to an ED50 of NOR and ANG were determined. All animals were then killed for determination of heart weight and adrenal weight. All groups had mean control period systolic BP values ranging from 143–146 mm Hg. In the no stress condition, neither GLA nor DUM altered BP over the course of the study. However, BP increased in the DUM group durign all four weeks of the isolation period vs the control period (p<0.01), whereas BP increased only in week 1 in the GLA group (p<0.05). Heart rate increased during stress in the DUM group (p<0.05), but not in the GLA group. Vascular reactivity to NOR was unaffected by GLA administration. In contrast, GLA increased the duration of the pressor response to ANG (p<0.01), but tended to decrease the magnitude of the pressor response (p<0.09) vs DUM. GLA had no effect on heart weight/body weight ratio. Adrenal weight/body weight ratio was lower in the DUM/no stress group than all other treatment groups.

These data indicate that GLA administration attenuates the cardiovascular responses to chronic stress in animals with a genetic predisposition to hypertension, in the absence of an effect on resting BP. They also demonstrate a limitation of GLA effect, in mature animals, to epigenetic pressor factors. Furthermore, GLA action may involve an alteration of the cardiovascular responses to ANG, but not NOR. These findings suggest that GLA may be useful in preventing the neurogenic triggering of hypertension by chronic stress in genetically stress‐sensitive animals.
Sex allocation in the polydomous leaf‐cutting antAcromyrmexbalzani
Authors: Ichinose Katsuya , Forti Luis C. , Pretto Denis R. , Nachman Gösta , Boomsma Jacobus J.
Published: November 2006

Logistic regression analysis was used to analyse sex allocation in a population of the leaf‐cutting antAcromyrmexbalzanioccurring in a pasture in southern Brazil. The field sample consisted of 151 fungus‐garden chambers (18 queenright and 133 queenless), belonging to 50 nests with three vertically stacked chambers per nest on average. Taking nest chamber as the unit of analysis, seven predictor variables were considered: sampling date, chamber depth, chamber volume, weight of fungus garden, presence of a queen, number of large workers, and number of small to medium workers. The population‐level numerical proportion of females was 0.548 and the inferred proportional energetic investment in females 0.672. The former was not significantly different from 0.5 (P=0.168), but the latter was (P=0.0003). The proportional investment in females per fungus garden increased with the number of large workers present (P=0.0002) and decreased with the dry weight of the fungus garden (P=0.012). This implies that resource acquisition through foraging is likely to be a major proximate determinant of sex allocation. The negative correlation between female bias and fungus garden weight might be due to developing adult females requiring more food than males, but this hypothesis could not be confirmed by direct statistical evidence.
Oxidative effects of animal‐originated porphyrins and riboflavin on cholesterol oxidation in an aqueous model system
Authors: Kim Jong‐Seung , Chung Myung‐Sub , Shin Hyo‐Sun
Published: November 2006

This study was executed to investigate effects of animal‐originated porphyrins and riboflavin on cholesterol oxidation in aqueous model systems. Changes of headspace oxygen contents, cholesterol, and cholesterol oxide products (COP) in the model systems were measured by gas chromatography during storage under light. As concentration of protoporphyrin increased, contents of headspace oxygen decreased and COP increased. The same trend as that of protoporphyrin occurred with riboflavin in terms of contents of headspace oxygen, but production of COP was the highest at 5 ppm riboflavin. As concentrations of hemoglobin and myoglobin increased, headspace oxygen content and COP production were not changed significantly. Consequently, protoporphyrin could be the most active catalyst on the cholesterol oxidation in the aqueous system, but myoglobin and hemoglobin did not accelerate cholesterol oxidation.
Simplified measurement of virgin olive oil color by application of the characteristic vector method
Authors: Moyano María José , Ayala Fernando , Echávarri J. Federico , Alba José , Negueruela A. Ignacio , Heredia Francisco J.
Published: November 2006

There are several simplified methods to measure the color of virgin olive oils. However, their reliability is questionable, as they provide errors that sometimes can be considerable. A new method to calculate color coordinates and objective chromatic parameters in the color region of these olive oils is proposed with the aim of overcoming these objections. The method is a simplification of the original method proposed by the Commission Internationale de l'Eclairage (CIE), based on the measurement of the complete visible spectrum, from 380 to 770 nm. The characteristic vector analysis provides new equations to calculate tristimulus values as functions of these transmittance values based on a reconstruction of oil transmission spectra measuring from three to six wavelengths. The results show that color differences exist between the color coordinates of the experimental samples and those obtained by means of the proposed method. For more than 90% of the samples, the difference was smaller than three CIELAB units when equations based on four or more wavelengths were used.
Dietary diacylglycerol prevents high‐fat diet‐induced lipid accumulation in rat liver and abdominal adipose tissue
Authors: Meng Xianghe , Zou Dongya , Shi Zhongping , Duan Zouying , Mao Zhonggui
Published: November 2006

The inhibitory effects of 1,3‐diacylglycerol (DAG) on diet‐induced lipid accumulation in liver and abdominal adipose tissue of rats were investigated in the present study. Male Sprague‐Dawley rats were given free access to diets containing 7 wt% TAG (low TAG), 20 wt% TAG (high TAG), or 20 wt% DAG (high DAG), respectively, for 8 wk. The body weight of rats in the 20% high‐TAG group increased significantly, and the weights of their abdominal adipose tissue and liver also showed a significant increase compared with rats in the low‐TAG group. However, the high‐DAG diet resulted in both a significant reduction in body weight gain (with a decrease of 70.5%) and an increase in the ratio of abdominal fat to body weight (by 127%) compared with the high‐TAG diet. As well, the liver TAG and serum TAG levels of the high‐DAG group were significantly lower than those of the high‐IAG group. These effects were associated with up‐regulation of acyl‐CoA carnitine acyltransferase (ACAT) and down‐regulation of acyl‐CoA DAG acyltransferase (DGAT) in the liver. However, no significant difference was observed in the activities of alanine aminotransferase and aspartate aminotransferase among the groups (P>0.05). The present results indicate that dietary DAG reduced fat accumulation in viscera and body, and these effects may be involved with up‐regulation of ACAT and down‐regulation of DGAT in the liver.
Hexane elimination from soybean oil by continuous packed tower processing with supercritical CO2
Authors: Reverchon E. , Poletto M. , Osséo L. Sesti , Somma M.
Published: November 2006

Hexane elimination is the most energy‐consuming step in the industrial extraction of soybean oil. It utilizes three sets of equipment: two evaporation stages in series followed by a stripper at a pressure of about 0.07 bar. The final hexane residue in the oil is about 1000 ppm. We propose an alternative to the present process for hexane elimination, based on the extraction of the soybean oil/hexane mixture with supercritical CO2 in a continuous countercurrent packed tower. In this work, we tested a soybean oil/hexane mixture feed containing 10% by weight of hexane. Various pressures and temperatures of the column were tested to reduce hexane residue in the oil. The extraction process was demonstrated to be very effective for hexane separation. Indeed, at the bottom of the column we recovered soybean oil containing quantities of hexane as low as 20 ppm when we operated at 120 bar, 40°C. The effect of process parameters is also discussed.
Comparative study of the extraction and measurement of cottonseed free fatty acids
Authors: Wan Peter J. , Dowd Michael K.
Published: November 2006

Crude oil was extracted from cottonseed by three different methods to study the influence of extraction technique on the free fatty acid (FFA) concentration. Extraction procedures that recovered more oil had higher levels of FFA. In addition, the highest concentration of FFA was found in oil recovered by Soxhlet reextraction of a meal initially defatted by a room‐temperature extraction process. The FFA concentrations of oils recovered by Soxhlet extraction were highly correlated with the FFA concentration of oils recovered by the other extraction methods studied (R2>0.96). Titration of oil and gas chromatography of silylated oil were compared as methods to determine FFA concentration. The methods compared well (R2=0.998) with the titration method, giving ∼5% higher values for FFA than the chromatography method. Half of this difference appeared to be due to the oleic acid approximation used in the titration approach. The other half of the difference is likely due to the detection of other acidic components in crude oil.
Discrimination of edible oil products and quantitative determination of their iodine value by Fourier transform near‐infrared spectroscopy
Authors: Li Hui , van de Voort F. R. , Ismail A. A. , Sedman J. , Cox R. , Simard C. , Buijs H.
Published: November 2006

This work demonstrates the application of partial least squares (PLS) analysis as a discriminant as well as a quantitative tool in the analysis of edible fats and oils by Fourier transform near‐infrared (FT‐NIR) spectroscopy. Edible fats and oils provided by a processor were used to calibrate a FT‐NIR spectrometer to discriminate between four oil formulations and to determine iodine value (IV). Samples were premelted and analyzed in gass vials maintained at 75°C to ensure that the samples remained liquid. PLS calibrations for the prediction of IV were derived for each oil type by using a subset of the samples provided as the PLS training set. For each oil formulation (type), discrimination criteria were established based on the IV range, spectral residual, and PLS factor scores output from the PLS calibration model. It was found that all four oil types could be clearly differentiated from each other, and all the validation samples, including a set of blind validation samples provided by the processor, were correctly classified. The PLS‐predicted IV for the validation samples were in good agreement with the gas chromatography IV values provided by the processor. Comparable predictive accuracy was obtained from a calibration derived by combining samples of all four oil types in the training set as well as a global IV calibration supplied by the instrument manufacturer. The results of this study demonstrate that by combining the rapid and convenient analytical capabilties of FT‐NIR spectroscopy with the discriminant and predictive power of PLS, one can both identify oil type, as well as predict IV with a high degree of confidence. These combined capabilities provide processors with better control over their process.
Adhesive properties of soy proteins modified by urea and guanidine hydrochloride
Authors: Huang Weining , Sun Xiuzhi
Published: November 2006

An investigation was conducted on the adhesive and water‐resistance properties of soy protein isolates that were modified by varying solutions of urea (1, 3, 5, and 8 M) or guanidine hydrochloride (GH) (0.5, 1, and 3 M) and applied on walnut, cherry, and pine plywoods. Soy proteins modified by 1 and 3 M urea showed greater shear strengths than did unmodified protein. The 3 M urea modification gave soy protein the highest shear strength. Soy proteins modified with 0.5 and 1 M GH gave greater shear strengths than did the unmodified protein. The 1 M GH‐modified soy protein gave the highest shear strength. Compared to the unmodified protein, the modified proteins also exhibited higher shear strengths after incubating with two cycles of alternating relative humidity, zero delamination, and higher remaining shear strengths after three cycles water soaking and drying. These results indicate that soy proteins modified with urea and GH enhance water resistance as well as adhesive strength. Secondary structures of globule proteins may enhance adhesion strength, and the exposure of hydrophobic amino acids may enhance water resistance. Proteins modified by 3 M urea or 1 M GH may have higher content of secondary structure and more exposed hydrophobic amino acids, compared with other modifications or unmodified proteins.
Determination of peroxide value by fourier transform near‐infrared spectroscopy
Authors: Li Hui , van de Voort F. R. , Ismail A. A. , Cox R.
Published: November 2006

A Fourier transform‐near infrared (FT‐NIR) method originally designed to determine the peroxide value (PV) of triacylglycerols at levels of 10–100 PV was improved upon to allow for the analysis of PV between 0 and 10 PV, a range of interest to the edible oil industry. The FT‐NIR method uses convenient disposable glass vials for sample handling, and PV is determined by spectroscopically measuring the conversion of triphenylphosphine (TPP) to triphenylphosphine oxide (TPPO) when reacted with hydroperoxides. A partial‐leastsquares calibration was developed for 8 mm o.d. vials by preparing randomized mixtures of TPP and TPPO in a zero‐PV oil. The method was validated with samples prepared by gravimetric dilution of oxidized oil with a zero‐PV oil. It was shown that the American Oil Chemists’ Society primary reference method was quite reproducible (±0.5 PV), but relatively insensitive to PV differences at lower (0–2) PV. The FT‐NIR method on the other hand was shown to be more accurate overall in tracking PV, but slightly less reproducible (0.9 PV) due to working close to the limit of detection. The sensitivity and reproducibility of the FT‐NIR method could be improved upon through the use of larger‐diameter vials combined with a detector having a wider dynamic range. The proposed FT‐NIR PV method is simple to calibrate and implement and can be automated to allow for routine quality control analysis of edible fats and oils.
Ultrasonic determination of the effect of shear on lipid crystallization
Authors: Garbolino Chiara , Ziegler Gregory R. , Coupland John N.
Published: November 2006

The design and calibration of a novel rheometer incorporating ultrasonic sensors are described. The instrument is capable of the simultaneous measurements of torque, rate of temperature change, and ultrasonic properties of a liquid as a function of time, temperature, and shear rate. The effect of shear rate on the crystallization onset temperature of a sample of confectionery coating fat is studied using this device. The instrument detected the phase transition in the sheared sample as abrupt changes in all of the measured parameters. The onset temperature increased significantly with shear rate, implying lipid crystallization can be accelerated by mixing. There were also significant differences between sensing modalities.
Storage stability of milled flaxseed
Authors: Malcolmson L. J. , Przybylski R. , Daun J. K.
Published: November 2006

Two samples of flaxseed, Linott and a mixture of several varieties, were milled and stored at 23±2°C for 128 d in paper bags with plastic liners. Samples were evaluated at 0, 33, 66, 96, and 128 d for chemical, sensory, and volatile indicators of quality. Neither the mixed variety nor Linott samples showed a significant increase in peroxide values or conjugated double bonds throughout the 128‐d storage period. Only the Linott sample showed a significant increase in free fatty acids, which was likely due to the presence of immature seed in the sample. Total volatiles increased with storage in the mixed variety sample but showed minimal change in the Linott sample. Overall, the levels of total volatiles in the milled flaxseed samples were much lower than levels reported in stored vegetable oils containing significantly lower levels of linolenic acid. Dienals, formed during polyunsaturated fatty acid oxidation, and hexanal, a compound used as an indicator of oxidative deterioration, were found at very low levels in both samples and did not reach high levels throughout the 128‐d storage period. A trained sensory panel could not detect any differences in the odor properties of fresh or stored milled samples. No differences in flavor could be detected between bread made with 0‐ and 128‐d milled flaxseed. This study showed that milled flaxseed can be stored up to 4 mon at ambient temperatures without noticeable changes in quality. The presence of endogenous antioxidants in the milled flaxseed may account for the stability observed.