bluuebunny/crossref_metadata_2025 huggingface dataset:
Incidence and severity of experimental allergic encephalomyelitis and cerebral prostaglandin synthesis in essential fatty acid deficient and aspirin‐treated rats
Authors: Weston Patricia G. , Johnston Patricia V.
Published: November 2006

Experimental allergic encephalomyelitis (EAE) was induced in rats of the Lewis strain fed diets adequate or deficient in essential fatty acids (EFA). After induction of the disease, the diets were supplemented with aspirin (3.75 g/kg diet), and the effects of the drug on the course of EAE and on the synthesis of prostaglandin F (PGF) by brain slices from diseased animals and their Freund controls were examined. Aspirin supplementation delayed the onset of EAE in both dietary groups. EFA‐deficient rats experienced an incidence and severity of the disease similar to that of aspirin‐free, EFA‐deficient rats, while the EFA‐adequate group showed a greater severity but not an increased incidence, compared to aspirin‐free controls. Aspirin treatment led to an increased PGF production by brain slices from rats on either diet and not subjected to an immunochallenge. When the diet was deficient in EFA, challenge with antigen plus adjuvant or adjuvant alone tended to decrease PGF synthesis by brain slices, and when the diet was adequate in EFA, immunochallenge caused a marked depression on PGF synthesis. It was concluded that the PG synthetase inhibitor aspirin can alter the course of EAE in the rat, providing further evidence that PGs or related metabolites may be involved in the immune response in this disease.
The role of dietary fat and hepatic triglyceride secretion in cancer‐induced hypertriglyceridemia
Authors: Kannan Ramaswamy , Wilson Leon , Baker Nome
Published: November 2006

Growth of Ehrlich ascites carcinoma induces hyperlipemia in mice. In the present study using male Swiss‐Webster mice, we examined whether the usual elevations of plasma triglyceride levels in cancerous mice would occur in the absence of dietary fat. Hypertriglyceridemia developed at a similar rate and to a comparable degree in tumorous mice eating a fat‐free (58% glucose) diet and in those fed Purina chow. Maximal hyperlipidemia was observed on day 6 or day 8 in tumorous mice fed either diet. To determine whether the endogenous cancer‐induced hyperlipidemia was due to hypersecretion of triglycerides by the liver, triglyceride secretion rates were studied 0, 2, 4, 6, 8, 10, and 12 days after tumor inoculation using Trition WR‐1339. The secretory rates did not increase prior to or during the development of hypertriglyceridemia in tumorous mice and were not significantly different from those of control mice. On days 10 and 12, triglyceride secretion actually decreased in tumorous mice. Other possible causes for hypertriglyceridemia are discussed in light of the present findings of undetectable differences in triglyceride secretion rates accompanying growth of Ehrlich ascites carcinoma in mice.
Separation of oxidized and unoxidized molecular species of phosphatidylcholine by high pressure liquid chromatography
Authors: Crawford C. G. , Plattner R. D. , Sessa D. J. , Rackis J. J.
Published: November 2006

Soy phosphatidylcholine (PC) has been separated into its major molecular species by reversephase high pressure liquid chromatography (HPLC). An aqueous methanol gradient was used that allowed detection of the various species by their absorbance at 206 nm. Oxidized species were detected by their absorbance at 234 nm and were resolved from the unoxidized species. This technique has been used to separate and purify unoxidized dilinoleyl phosphatidylcholine (di 18∶2 PC) from other species of soy PC and to monitor the autoxidation of an aqueous suspension of the purified di 18∶2 PC. Two oxidized products were formed from di 18∶2 PC. Further analysis showed that they were PC, but one of the products contained an oxidized and an unoxidized fatty acid; in the other product, both fatty acids were oxidized.
10α‐Cucurbita‐5,24‐dien‐3β‐ol from gourd seed oil
Authors: Itoh Toshihiro , Tamura Tsutomu , Jeong Tae Myoung , Tamura Toshitake , Matsumoto Taro
Published: November 2006

10α‐Cucurbita‐5,24‐dien‐3β‐ol was isolated from the unsaponifiable matter of the seed oil of gourd (Lagenaria leucantha var.Gourda; Cucurbitaceae); it has been previously synthesized, but never found in the plant kingdom. The triterpene alcohol represents the parent compound of a number of cucurbitacins, highly oxygenated tetracyclic triterpenes found in Cucurbitaceae and some other flowering plants.
Distribution of neutral lipids in the tissues of the oysterCrassostrea virginica
Authors: Swift Mary L. , White Debra , Ghassemieh Mohammad B.
Published: November 2006

The content of neutral lipids was determined in the tissues of oysters (Crassostrea virginica Gmelin) collected in June, July and March. The lipid content of starved March oysters was also determined. Oyster tissue from the June harvest contained the highest quantities of triglyceride; starved and July (late spawning) oysters had decreased levels of triglycerides in all tissues except the digestive diverticula/gonad. Free sterol content of all the tissues averaged 1.21 mg equivalent cholesterol/g wet weight tissue, and the steryl ester concentration averaged about 10% of this value. Findings of this investigation indicate that the triglyceride content of oyster tissue fluctuates seasonally and is there‐fore keyed to the physiological state of the animal. Furthermore, triglycerides may be an important energy reserve for reproductive tissue.
Stereospecific analysis of glycerolipids of egg yolk of Japanese quail (Coturnix coturnix japonica)
Authors: Suyama Kyozo , Adachi Susumu , Sugawara Hiroshi , Honjoh Hidemi
Published: November 2006

Phosphatidylcholine, phosphatidylethanolamine and triacylglycerol were isolated from egg yolk of the Japanese quail. Fatty acid compositions at the two and three positions of glycerol in the glycerolipids were determined by stereospecific analysis employing phospholipase A2. The distribution of the total number of carbon atoms in the fatty acid moieties of triacylglycerol was also quantitated by high temperature gas liquid chromatography. The distribution of acyl groups in each of the positions of the phosphatidylcholine, phosphatidylethanolamine and triacylglycerol was not random, and each position has a characteristic composition. The phosphatidylcholine and phosphatidylethanolamine had distinctive fatty acid distributions for positionsn‐2 of the triacylglycerol had a predominance of unsaturated fatty acids of which 18∶1 (69.9%) was the major component. Positionsn‐3 contained 49.3% saturated fatty acids and was more saturated than positionsn‐1 by 8.1%. The experimentally determined distribution of the carbon numbers in triacyl glycerol deviated significantly from the distribution predicted by 1‐random‐2‐random‐3‐random association of the fatty acids. The data suggest that in Japanese quail there is marked preferencial synthesis of some triacylglycerols.
Oxidation and isomerization of retinoic acid by iodine and light: A novel preparation of all‐trans‐ and 13‐cis‐4‐oxoretinoic acid
Authors: McKenzie R. M. , Hellwege D. M. , McGregor M. L. , Nelson E. C.
Published: November 2006

A mixture of all‐trans‐retinoic acid and iodine in heptane was irradiated. Two oxidation products were isolated by high performance liquid chromatography and identified as all‐trans‐ and 13‐cis‐4‐oxoretinoic acid by nuclear magnetic reasonance, ultra violet, Infrared spectroscopy, and mass spectral analysis. Under the same conditions, but without light, a mixture of all‐trans‐ and 13‐cis‐retinoic acid resulted. The corresponding methyl esters were obtained when methyl all‐trans‐retinoate was used in place of all‐trans‐retinoic acid.
Effect of low levels of dietary fish oil on fatty acid desaturation and tissue fatty acids in obese and lean rats
Authors: Cao Jun‐Ming , Blond Jean Paul , Juaneda Pierre , Durand Georges , Bézard Jean
Published: November 2006

The effect of very low levels of dietary long‐chain n−3 fatty acids on Δ6 desaturation of linoleic acid (18∶2n−6) and α‐linolenic acid (18∶3n−3), and on Δ5 desaturation of dihomo‐γ‐linolenic acid (20∶3n−6), in liver microsomes and its influence on tissue fatty acids were examined in obese and lean Zucker rats and in Wistar rats. Animals fed for 12 wk a balanced diet containing ca. 200 mg of long‐chain polyunsaturated n−3 fatty acids per 100 g of diet were compared to those fed the same amount of α‐linoleic acid. Low amounts of long‐chain n−3 fatty acids greatly inhibited Δ6 desaturation of 18∶2n−6 and Δ5 desaturation of 20∶3n−6, while Δ6 desaturation of 18∶3n−3 was not inhibited in Zucker rats and was even stimulated in Wistar rats. Inhibition of the biosynthesis of long‐chain n−6 fatty acids was reflected in a decrease in arachidonic acid (20∶4n−6) content of serum lipids when fasting, and also in the phospholipid fatty acids of liver microsomes. On the contrary, heart and kidney phospholipids did not develop any decrease in 20∶4n−6 during fish oil ingestion. Docosahexaenoic acid (22∶6n−3), present in the dietary fish oil, was increased in serum lipids and in liver microsome, heart, and kidney phospholipids.
Hepatic lipid abnormalities in a chemical/viral mouse model for Reye's Syndrome
Authors: Murphy M. G. , Archambault‐Schertzer L. , VanKessel J. , Digout S. C. , Malatjalian D. A. , Crocker J. F. S.
Published: November 2006

We have examined hepatic lipid profiles in a mouse model for Reye's Syndrome (RS) in which young animals are exposed to nontoxic doses of an industrial pesticide emulsifier and subsequently are infected with sublethal doses of mouse‐adapted human Influenza B (Lee) virus (FluB). The purpose of this study was to determine whether liver lipid content was altered in the mice, the time course of any changes, and whether lipid changes were consistent with liver pathology. Neonatal mice exposed dermally to the emulsifier, Toximul MP8 (Tox), had significantly elevated levels of hepatic cholesterol, with otherwise normal lipid composition. Subsequent inoculation of the mice with FluB significantly increased mortality rate. The combined Tox+FluB treatment had several significant effects on liver lipids, including a transient increase in phospholipid (PL) content, a reduction in neutral glycerides and persistently high cholesterol levels. Abnormalities in fatty acid profiles included an apparent elevation in medium chain fatty acids and increased ratios of PL arachidonic to docosahexaenoic acids. Histologically, there was no evidence of fat accumulation in the liver; however, hepatic mitochondria had severe structural abnormalities characteristic of RS. These studies demonstrate that chemical‐dependent enhancement of viral virulence is associated with significant alterations of hepatic lipids. We believe that these abnormalities are related to mitochondrial structural damage in RS despite the absence of hepatic steatosis.
Effects of aging on the composition and metabolism of docosahexaenoate‐containing lipids of retina
Authors: Rotstein N. P. , Ilincheta de Boschero M. G. , Giusto N. M. , Aveldaño M. I.
Published: November 2006

The amount of docosahexaenoate (22∶6n−3)‐containing phospholipid species decreases with aging in the rat retina. Most lipids, but especially choline and serine glycerophospholipids, show a significant fall in 22∶6n−3, which is not compensated by increases in other polyenoic fatty acids. The decrease not only affects 22∶6 but also various very long chain n−3 hexaenoic fatty acids which, in phosphatidylcholine, have up to 36 carbon atoms, and which are probably synthesized by successive elongations of 22∶6n−3. The in vitro incorporation of [2‐3H] glycerol into retinal lipids indicates that the de novo biosynthetic pathways are not impaired by aging. The incorporation of [1‐14C]docosahexaenoate is significantly stimulated into all lipids of aged retinas, but to the largest extent in those showing the largest decreases in 22∶6, especially in choline glycerophospholipids. The results indicate that the decreased levels of 22∶6 with aging are due not to an impaired activity of the enzymes involved in the synthesis and turnover of phospholipids but to a decreased availability of this polyene in the retina. It is suggested that this may stem from a defect in some of the enzymatic steps that lead to the synthesis of 22∶6n−3, probably that catalyzed by Δ4 desaturase, the effect on longer hexaenes being secondary to the decreased synthesis of 22∶6.
Two procedures to remove polar contaminants from a crude brain lipid extract by using prepacked reversed‐phase columns
Authors: Kyrklund Titus
Published: November 2006

Two procedures were developed using prepacked, reversed‐phase columns (Bond Elut) for the separation of lipids from water‐soluble contaminants. A crude lipid extract from brain tissue, was diluted stepwise with a methanol/water (method 1) or a methanol/saline (method 2) mixture and, with each step, was passed through the column. As the polarity of the solvent was increased, all lipids became bound to the column, while the water‐soluble compounds remained in the eluate. After three subsequent dilutions and column elutions, the eluate containing the more polar contaminants was discarded. The bound lipids were then eluted with a small volume of chloroform/methanol (1∶2, v/v). Alternatively two fractions were eluted, the first fraction eluted with methanol/water (12∶1, v/v), contained gangliosides, phosphatidyl‐serine, phosphatidylinositol, phosphatidic acid and sulfatides. The second fraction, eluted with chloroform/methanol (1∶2, v/v), contained all remaining phospholipids, cerebrosides and cholesterol. For both methods a quantitative recovery of cholesterol and phospholipids was obtained. In method 2, when water was replaced by saline in the dilution solvent mixture, gangliosides were also bound and quantitatively recovered.
Effect of age and dietary fat (fish, corn and coconut oils) on tocopherol status of C57BL/6Nia mice
Authors: Meydani Simin Nikbin , Shapiro Alice C. , Meydani Mohsen , Macauley John B. , Blumberg Jeffrey B.
Published: November 2006

The effect of age and dietary fat type on tocopherol status was investigated using young and old C57BL/6Nia mice fed semipurified diets containing 5% (by weight) fish, corn or coconut oils and supplemented with 30, 100 or 500 ppm dl‐α‐tocopheryl acetate for 6 wk. Tocopherol levels in the diets, plasma, liver, kidney and lung were measured by high performance liquid chromatography following appropriate extractions. The results indicate that mice fed fish oil maintain lower plasma and tissue tocopherol concentrations than those fed corn and cononut oils (fish<corn oil<coconut oil). The difference was not due to a loss of tocopherol prior to consumption, but rather appeared to occur during the absorption process. Old mice had lower plasma and liver tocopherol concentrations than young mice. Old mice fed fish oil, however, maintained plasma tocopherol levels better than young mice fed fish oil, presumably due to their larger tocopherol pool. No age effect was detected on kidney and lung tocopherol levels. It is concluded that tocopherol status is affected by age and dietary fat type, especially fish oil.
Quantitation of baboon lipoproteins by high performance gel exclusion chromatography
Authors: Williams Mary C. , Kushwaha Rampratap S. , McGill Henry C.
Published: November 2006

High performance liquid chromatography with gel exclusion columns was used for quantitative measurement of plasma lipoproteins. A combination of columns TKS 4000 PW and 3000 PW gave good separation of very low (VLDL), low (LDL) and high (HDL) density lipoproteins. The area under each lipoprotein peak detected by absorbance at 280 nm was measured by digitizing and was expressed as cm2. Purified lipoprotein standards isolated by ultracentrifugation were also chromatographed in increasing concentrations. The area under the lipoprotein standard peak was linearly related to the amount of total protein over a wide range. The areas of most of the measured plasma lipoproteins were within the linear range. The relationship between the area and the amount of protein for each standard was used to quantitate the amount of protein and was expressed as mg/dl plasma. This technique is simple and requires a small amount of plasma. The validated technique was applied to a large population of pedigreed baboons. An average plasma lipoprotein profile of feral baboons on the chow diet was characterized by a high level of HDL (90.9±30.7 mg/dl) with a lesser amount of LDL (29.1±13.2 mg/dl). VLDL was present in much lower concentration (8.6±2.6 mg/dl). Feeding a high cholesterol and high saturated fat (HCHF) diet raised both LDL (1.5‐fold) and HDL levels (1.3‐fold) without changing VLDL levels. Progeny of sires with low response to dietary cholesterol increased their HDL protein when challenged with HCHF diet without any change in their LDL or VLDL. Progeny of high‐responding sires, however, had increases in both their HDL and LDL levels when challenged with HCHF diet. The survey of lipoprotein profiles of the pedigreed baboon colony disclosed a number of animals with interesting and unusual lipoprotein patterns.
Identification of steroids by chemical ionization mass spectrometry
Authors: Lin Yong Y.
Published: November 2006

Chemical ionization (CI) mass spectra of various natural and synthetic steroids have been studied using methane, isobutane, ammonia, trideuterioammonia and hydroxy anion as reagent gases. The CI spectra of steroids give simple and well characterized ions, which provide information about molecular weight as well as functionalities in the molecules. Trideuterioammonia exchanges rapidly with active hydrogens (e.g., OH, SH, COOH, NH2) in steroid molecules in the CI reaction and thus provides a convenient means of active hydrogen determination by mass spectrometry. Application of various CI processes to the analysis of steroids and conjugates have been made. Low levels of hydroxycholesterols in biological samples and in cholesterol autoxidation products were identified by the 4 ion patterns, [M+NH4]+, [M−OH+NH3]+, [M−OH]+ and [M−H2 O−OH]+, in ammonia CI. The position of hydroxy functions in the cholesterol side chain can be identified from the methane CI of hydroxycholesterol trimethylsilyl (TMS) derivatives. Sterol carboxylic esters can be identified as the ammonium adduct ion of the intact molecule, [M+NH4]+, in ammonia CI. Isobutane and hydroxy anion CI spectra of the steroid esters give abundant ion fragments of both steroids and carboxylic acid moieties. Identification of free bile acids and steroid glycosides without derivatization is also feasible with the CI process when ammonia is used as reagent gas.
Analysis and structure determination of unsaturated 5β‐cholanoic acids
Authors: Kuksis A. , Child P.
Published: November 2006

Unsaturated cholanoic acids are known to arise as artifacts of chemical transformation processes and during storage and high‐temperature gas liquid chromatography (GLC) of various derivatives of saturated bile acids. Nevertheless, there is evidence for their natural occurrence and isolation under conditions where artifactual formation of unsaturated bile acids would be unlikely. Since structural identification of such compounds is often complicated by a lack of knowledge of their analytical properties, a representative series of monounsaturated cholanoic acids with double bonds in rings A, B and C were prepared by POCl3 and ZnCl2 dehydration of saturated bile acids with selectively blocked hydroxyl functions. The cholenoic acids were indistinguishable from their saturated analogs by thin layer chromatography (TLC) on plain silica gel, but those compounds with sterically exposed double bonds were resolved by AgNO3‐TLC, using chloroform/methanol solvent systems. The synthetic 5β‐cholenoic acids obeyed the general rules of GLC mobility based on the overall shape of the molecule and the number and configuration of the functional groups. Constant retention factors attributable to the double bond were observed for all of the double bond types on several GLC phases, and theoretical retention times could be calculated for combinations of double bonds and functional groups not specifically represented among the synthetic standards. With gas chromatography‐mass spectrometry (GC‐MS), the unsaturated bile acids gave several characteristic fragments, which, in conjunction with the chromatographic properties of the parent compounds, permitted an unambiguous distinction among different unsaturated acids, and between unsaturated and saturated bile acids of the same number and configuration of functional groups. For complete structural identification of saturated and unsaturated bile acids, capillary GC‐MS represents the ideal state of the art, but the less expensive combination of AgNO3‐TLC and GLC also can yield much useful information concerning the structure of natural and synthetic 5β‐cholenoic acids. This study emphasizes the need for special precautions in the isolation and derivatization of bile acids intended for studies of unsaturated components.
Reduction of essential fatty acid deficiency in rats fed a low iron fat free diet
Authors: Ananda Rao G. , Manix Marcia , Larkin Edward C.
Published: November 2006

Young male rats were fed ad libitum for 8 weeks a low iron fat‐free (FF‐Fe) diet or a fat‐free diet supplemented with iron (FF+Fe). The relative levels of 16∶1 to 16∶0 and 18∶1 to 18∶0 in the total fatty acids of liver and other tissues (plasma, erythrocytes and intestinal mucosa) were considerably decreased because of a lack of dietary iron. In rats fed the FF‐Fe diet, the levels of essential fatty acids (18∶2ω6+20∶4ω6) in tissues were 2‐to 3‐fold greater than in the corresponding tissues of rats fed the FF+Fe diet. Eicosatrienoic acid (20∶3ω9) levels in tissue lipids from rats fed the FF+Fe diet were high (8–16%), whereas they were low (2–5%) in the case of animals fed the FF‐Fe diet. The proportion of 20∶4 in total fatty acids of tissues was 2‐to 3‐fold greater in rats fed the FF‐Fe diet than when they were fed the FF+Fe diet. Therefore, the relative levels of 20∶3ω9/20∶4ω6 varied from 1‐2.9 in tissue lipids of rats fed the FF+Fe diet, while it varied only from 0.2–0.3 in animals fed the FF‐Fe diet. These results suggest that a lack of dietary iron may reduce the synthesis of 16∶1, 18∶1, 20∶3 and 20∶4 and the metabolism of 20∶4.
Identification of chondrillasterol in twoCucurbitaceae seed oils by proton nuclear magnetic resonance spectroscopy
Authors: Iida T. , Jeong T. M. , Tamura T. , Matsumoto T.
Published: November 2006

The absolute configuration at C‐24 of C‐24 epimeric 24‐ethyl‐5α‐cholesta‐7,E‐22‐dien‐3β‐ols I–IV previously isolated from tea seed oil, shea fat, and gourd and sponge cucumber seed oils, respectively, was studied by proton nuclear magnetic resonance spectroscopy. The results showed that the sterols I and II are identical with spinasterol (24S/α‐ethyl group), whereas the sterols III and IV are identified as its 24R/β‐epimer, chondrillasterol. This study has thus for the first time properly documented the presence in tracheophytes of a 24β‐ethylsterol in which Δ25(27)‐bond is reduced.
Subfractionation and characterization of native and incubation enlarged human plasma high density lipoprotein particles by high performance gel filtration
Authors: Holmquist Leif , Carlson Lars A.
Published: November 2006

Incubation of human plasma in vitro at 37 C results in an increase of the mean particle size of the high density lipoproteins (HDL) accompanied by an almost complete disappearance of the original particles present prior to incubation.

A rapid high performance gel filtration technique has been developed in order to study the chemical composition of subfractions of native and incubation enlarged HDL particles as a function of particle size. Subfractionation of HDL isolated by preparative ultracentrifugation from 3 normal human plasmas incubaed in vitro at 0 and 37 C for 24 hr have been performed using a 150 cm long TSK‐G 3000 SW column. The separation time was less than 65 min.

The curves obtained at high performance gel filtration of HDL, by monitoring the effluents from the column at 280 nm, agreed well both in positions of peak maxima and relative peak intensities with the particle distribution patterns observed at polyacrylamide gradient gel electrophoresis of the corresponding HDL preparations run in parallel. The different HDL particle subfractions of the effluents from the gel filtration column have been characterized by quantification of free and esterified cholesterol, total phospholipids and apolipoprotein A‐I and A‐II.

The incubation enlarged HDL particles, subfractionated by the high performance gel filtration technique, were found to have a composition which differed from that of native HDL particles of corresponding size. Incubation enlarged HDL had a generally higher and almost constant relative cholesteryl ester content over the whole particle range compared to native HDL in which a continuous increase in relative cholesteryl ester content could be observed when going from large to small particles.

The molar ratio of phospholipids to free cholesterol was higher in small native HDL particles than in the corresponding large ones. The relation between apolipoprotein A‐I and A‐II remained nearly constant between small and large HDL particles in each subfractionation experiment. The results demonstrate that the high performance gel filtration technique is a rapid and reproducible means for studying the composition of subfractions of HDL particle populations.
The monoenoic fatty acid composition of a marine species ofDesulfobulbus grown on lactate
Authors: Taylor James , Parkes R. John , Wahle Klaus W. J. , Calder A. Graham
Published: November 2006

The proportions of isomeric monoenoic fatty acids from cell lipids of a marine, anaerobic, sulphatereducing bacteriumDesulfobulbus, grown on lactate, were determined by pyrrolidide derivatization and GC‐MS analysis. The predominant fatty acid was C17ŋ1, Δ11 with much smaller proportions of C16∶1, Δ11 and C18∶1, Δ11 and small (<5%) yet significant proportions of C15∶1, Δ11; C16∶1, Δ9; C17∶1, Δ9 and C18∶1, Δ9. If the spectrum of isomers obtained from this organism were synthesized entirely by the anaerobic pathway, it would indicate a wider chain‐length specificity for the ratelimiting β‐hydroxy acyl dehydrase than hitherto has been reported. The high proportion of oddnumbered fatty acids reflected the chain initiation by propionate derived from lactate. The possibility of monoene synthesis by an anaerobic Δ9‐desaturase mechanism is discussed.
Mass spectrometry of isomeric fatty acid hydroperoxides by chemical ionization via direct exposure probe
Authors: Plattner R. D. , Gardner H. W.
Published: November 2006

Intact isomeric methyl 9‐ and 13‐hydroperoxy linoleates are analyzed by chemical ionization (CI) mass spectrometry using a direct exposure probe. Both isobutane and ammonia CI spectra were obtained. With isobutane CI, ions are observed for protonated fragments that are indicative of an acid catalysis mechanism similar to that observed in solution, whereas ammonia CI yields primarily adduct ions. The collisionally activated decomposition daughters of the high mass ions can be used to identify the position of the hydroperoxy group in the isomers studied.
Fatty acid metabolism and cell proliferation. VII. Antioxidant effects of tocopherols and their quinones
Authors: Lindsey Jenifer A. , Zhang Hanfang , Kaseki Hisayuki , Morisaki Nobuhiro , Sato Takasi , Cornwell David G.
Published: November 2006

The antioxidant capacities of α‐ and γ‐tocopherols (α‐E and γ‐E) and their quinones (α‐EQ and γ‐EQ) were determined in non‐biological and biological systems. The non‐biological system consisted of arachidonic acid [20∶4 (n−6)], the oxidant cumene hydroperoxide, and a Fe3+ catalyst to facilitate malondialdehyde (MDA) formation from lipid peroxides. α‐E and γ‐E had similar antioxidant capacities in this system. α‐EQ also functioned as an antioxidant, while γ‐EQ exhibited a crossover effect by functioning as an antioxidant at low concentrations and a prooxidant at high concentrations. Biological lipid peroxidation in smooth muscle cells challenged with 20∶4 (n−6) was measured both by MDA formation in confluent cultures and by cell growth in proliferating cultures. α‐E, γ‐E and α‐EQ had similar antioxidant capacities, but γ‐EQ was highly cytotoxic for cells in both confluent and proliferating cultures. Cellular retention of antioxidants was estimated indirectly from MDA formation when cells were loaded with an antioxidant (preincubation) and then incubated for varying periods of time in fresh media containing 20∶4 (n−6). Cellular retention also was measured directly with tritiated α‐E and tritiated αEQ. These studies showed that cellular retention decreased in the sequence γ‐E>α‐E>α‐EQ. Thus, cellular retention does not explain the enhanced antioxidant capacity of α‐E compared to γ‐E that has been reported for animal systems. The antioxidant capacity of αE evidently is enhanced by its metabolism to a quinone which, unlike the quinone from γ‐E, functions as a biological antioxidant.
Influence of dietary partially hydrogenated vegetable and marine oils on membrane composition and function of liver microsomes and platelets in the rat
Authors: Blomstrand Rolf , Diczfalusy Ulf , Sisfontes Leslie , Svensson Lennart
Published: November 2006

The aim of the present study was to investigate the influence of partially hydrogenated vegetable and marine oils on membrane composition and function of liver microsomes and platelets with particular reference to the metabolism of linoleic acid and the production of arachidonic acid metabolites. Four groups of male weanling rats were fed linoleic acid supplemented diets containing 20% (w/w) of partially hydrogenated low erucic acid rapeseed oil (HLRSO), partially hydrogenated herring oil (HHO), olive oil (OO) and trierucin + triolein (TE) for 10 weeks. An additional two groups were fed partially hydrogenated low erucic acid rapeseed oil and partially hydrogenated herring oil without linoleic acid supplementation (HLRSO‐ and HHO‐, respectively).

Substantial amounts oftrans fatty acids were incorporated into liver microsomes (12.6% in group HLRSO) and platelets (7.0% in group HLRSO‐). This incorporation was not dependent on the dietary linoleic acid level. Hepatic microsomal Δ5‐desaturase activity was significantly increased after HLRSO feeding compared to OO feeding. Δ6‐Desaturase activity did not vary in the linoleic acid supplemented groups. Both Δ5‐ and Δ6‐desaturase activities were significantly increased in groups without linoleic acid supplementation.

Docosenoic acid was incorporated into platelet phospholipids in contrast to liver microsomes. In the platelet, docosenoic acid seemed to have a special preference for phosphatidylserine. Very small amounts were incorporated into platelet phosphatidylinositol. Feeding diets HLRSO, HHO and OO did not influence rat platelet cyclooxygenase or 12‐lipoxygenase activity. Platelets from rats fed TE, however, produced significantly less 12‐hydroxy‐5,8,10,14‐eicosatetraenoic acid (12‐HETE) than platelets from rats fed OO. Feeding of HLRSO‐ and HHO‐ resulted in a significantly diminished production of the arachidonic acid metabolites 12‐HETE, 12‐hydroxy‐5,8,10‐heptadecatrienoic acid (HHT) and 6‐keto‐prostaglandin F1α in stimulated platelets and aorta. Thus, high dietary levels oftrans isomers of monoenoic acids do not interfere with platelet cyclooxygenase or lipoxygenase activity provided sufficient amounts of linoleic acid are available.
Dimers formed in oxygenated methyl linoleate hydroperoxides
Authors: Miyashita Kazuo , Hara Nobuko , Fujimoto Kenshiro , Kaneda Takashi
Published: November 2006

The formation of dimers was demonstrated in methyl linoleate hydroperoxides decomposed by bubbling with dry air at 30 C. The dimer fraction isolated by gel permeation chromatography was further fractionated by successive silicic acid column and high performance liquid chromatography. Major components were analyzed after derivatizations by gas chromatography‐mass spectrometry with several ionization methods, i.e., electron impact, chemical ionization and field desorption.

After aeration for 90 min, 1.4% of the hydroperoxides were decomposed. However, almost all of the secondary products were dimers, while polar monomeric and low molecular products were negligible. After aeration for 390 min, both polar monomeric (5.0%) and low molecular (0.8%) compounds formed, but dimers and polymers (18.1%) were still the major products. These results show the importance of polymerization in the aerobic breakdown of hydroperoxides.

The dimers isolated from hydroperoxides aerated 90 min could be separated into two fractions according to their polarities. The dimers identified usually were composed of octadecadienoate and oxygenated octadecenoate moieties crosslinked through either ether or peroxy linkages across C‐9 or C‐13 positions. The oxygen‐containing functional groups found in the dimers include hydroperoxy, hydroxy and oxo groups. The polar dimers had two of these groups per molecule, while the less polar dimers had one. The main constituents of dimers were linked through peroxy bridges and found to be similar to the dimers previously identified in autoxidized methyl linoleate. These dimers are suggested as important intermediates in linoleate oxidation and as precursors of flavor deterioration.
Chemical defence, offence and alliance in ants–aphids–ladybirds relationships
Authors: Pasteels Jacques M.
Published: November 2006

Chemicals, which mediate the interactions between aphids, ladybirds and ants, are reviewed. Special emphasis is laid on autogenous and plant‐derived chemical defence in aphids and ladybirds. Evidences for chemical cues used during foraging and oviposition in ladybirds are assessed. Possible mutualistic interaction between plants and the third trophic level is illustrated by the as yet few reports of indirect plant‐defence volatiles induced by aphids or coccids attracting parasitoids or ladybirds. The use of chemical signals allowing aphid parasitoids or ladybirds to squeeze into ant–aphid mutualistic association is briefly described. Questions are raised and hypotheses suggested which could stimulate further research on aphid host‐plant influence on ladybird foraging behaviour and fitness, and on the cues used by aphid‐web partners for their mutual recognition.
Breeding migration and population stability
Authors: Nakazawa T. , Yamamura N.
Published: November 2006

We have modeled habitat shift for reproduction to examine the relationship between the timing of migration and population stability, by modifying Takimoto's (Am Nat 162:93–109, 2003) consumer–resource model with a consumer's ontogenetic niche shift. We found that equilibrium was always locally unstable if migration occurs at a fixed time or level of energy storage, whereas it could be stable if the timing of migration was adaptively flexible to maximize reproductive output. The general conditions for stability were safer breeding rather than feeding habitat and abundant resources at the feeding habitat. These results imply that both adopting an adaptive plastic strategy in the timing of migration and choosing to migrate from a rich feeding habitat to a safe breeding habitat can contribute to population stability. We also found that reduced reproductive success with delays in migration, and the survival rate after reproduction, had complicated effects on stability, depending on resource availability at the feeding habitat. The equilibrium was more likely to be stable when reproduction success was only slightly (or greatly) reduced or survival rate was high (or low) if the feeding habitat was rich (or poor). These are significant predictions for ecological study of migrating animals.
Oxidative stability of virgin olive oils
Authors: Cinquanta L. , Esti M. , Di Matteo M.
Published: November 2006

An investigation was carried out on virgin olive oils of the Gentile (Larino), Gentile (Colletorto), Coratina, and Leccino varieties, harvested at different times, to assess their oxidation stability. The olive oils were analyzed by means of peroxide, K232′ and K270 values at 1, 6, 12, and 18 mon of storage in green bottles, in the dark, at temperatures ranging from a mean of 6°C in winter to 12°C in summer. A subsample was also oven‐tested at 75°C and then analyzed on a weekly basis using the same oxidative parameters. The less ripe the olives (harvested in the same area during 1 mon), the more resistant the olive oils were to forced oxidation. The amount of total phenols in the oils was found to be directly related, even if to a low degree, to the oleuropein content in the olives and inversely related, to the same degree, to (3,4‐dihydroxyphenyl)ethanol. The latter is a derivative of oleuropein; (3,4‐dihydroxyphenyl)ethanol content increases as the olives ripen, but it is very low in fresh virgin olive oils, owing to the hydrophilic nature of the phenolic alcohol, which goes mainly into the waste‐water during processing. Among the varieties considered, Coratina oils showed the highest resistance to forced oxidation because of their high total phenol content.
Frying performance of low‐linolenic acid soybean oil
Authors: Tompkins Carol , Perkins Edward G.
Published: November 2006

The frying performance of low‐linolenic acid soybean oil from genetically modified soybeans was examined. Partially hydrogenated and unhydrogenated low‐linolenic acid soybean oils were compared to two partially hydrogenated soybean frying oils. Frying experiments utilizing shoestring potatoes and fish nuggets were conducted. Frying oil performance was evaluated by measuring free fatty acid content, p‐anisidine value, polar compound content, soap value, maximal foam height, polymeric material content, and Lovibond red color. The hydrogenated low‐linolenic soybean oil (Hyd‐LoLn) consistently had greater (P<0.05) free fatty acid content and lower p‐anisidine values and polymeric material content than did the other oils. Hyd‐LoLn generally was not significantly different from the traditional oils for polar content, maximal foam height, and Lovibond red color. The low‐linolenic acid soybean oil (LoLn) tended to have lower soap values and Lovibond red color scores than did the other oils. LoLn had consistently higher (P<0.05) p‐anisidine values and polymeric material content than did the other oils, and LoLn generally was not different (P<0.05) from the traditional oils for polar content, maximal foam height, and free fatty acid.
The effect of minor components on milk fat crystallization
Authors: Wright Amanda J. , Hartel Richard W. , Narine Suresh S. , Marangoni Alejandro G.
Published: November 2006

Milk fat is composed of 97–98% triacylglycerols and 2–3% minor polar lipids. In this study triacylglycerols were chromatographically separated from minor components. Isolated diacylglycerols from the polar fraction were also added back to the milk fat triacylglycerols. The crystallization behaviors of native anhydrous milk fat (AMF), milk fat triacylglycerols (MF‐TAG), and milk fat triacylglycerols with diacylglycerols added back (MF‐DAG) were studied. Removal of minor components and addition of diacylglycerols had no effect on dropping points or equilibrium solid fat contents. Presence of the minor components, however, did delay the onset of crystallization at low degrees of supercooling. Crystallization kinetics were quantified using the Avrami model. Sharp changes in the values of the Avrami constant k and exponent n were observed for all three fats around 20.0°C. Increases in n around 20.0°C indicated a change from one‐dimensional to multidimensional growth. Differences in k and n of MF‐DAG from AMF and MF‐TAG suggested that the presence of milk fat diacylglycerols changes the crystal growth mechanism. Apparent free energies of nucleation (ΔGc,apparent) were determined using the Fisher‐Turnbull model. (ΔGc,apparent) for AMF was significantly greater than ΔGc,apparent for MF‐TAG, and ΔGc,apparent for MF‐DAG was significantly less than those for both AMF and MF‐TAG. The microstructural networks of AMF, MF‐TAG, and MF‐DAG, however, were similar at both 5.0 and 25.0°C, and all three fats crystallized into the typical β′‐2 polymorph. Differential scanning calorimetry in both the crystallization and melting modes revealed no differences between the heat flow properties of AMF, MF‐TAG, and MF‐DAG.
Enzymatic synthesis of 1,3‐dicapryloyl‐2‐eicosapentaenoylglycerol
Authors: Irimescu Roxana , Yasui Mamoru , Iwasaki Yugo , Shimidzu Nobuyoshi , Yamane Tsuneo
Published: November 2006

1,3‐Dicapryloyl‐2‐eicosapentaenoylglycerol (CEC) was synthesized by interesterification of trieicosapentaenoylglycerol (EEE) with ethyl caprylate (EtC) catalyzed by LipozymeTM. After some of the reaction conditions were optimized, the maximal molar content of CEC in the glycerides of the reaction mixture was 91%. Among the parameters studied in the optimization, the critical ones were: (i) the water content, which influenced the conversion of EEE to CEC and 1‐capryloyl‐2‐eicosapentaenoylglycerol (CEOH), and (ii) the timing of water removal under reduced pressure for the reesterification of CEOH to form CEC. The complete synthesis of CEC from ethyl eicosapentaenoate (EtE) was performed in three steps: (i) hydrolysis of EtE to free eicosapentaenoic acid (EPA), (ii) esterification of glycerol with EPA to form EEE, and (iii) interesterification of EEE with EtC under the optimized conditions. The first two steps were catalyzed by NovozymTM and the third by LipozymeTM. The total yield over all the steps was 88%, and no purification of the intermediates was necessary. The regioisomeric purity of the product was 100% by silver‐ion high‐pressure liquid chromatography.
Deacidification of corn oil by solvent extraction in a perforated rotating disc column
Authors: Pina Carla G. , Meirelles Antonio J. A.
Published: November 2006

The deacidification of corn oil by continuous liquid‐liquid extraction was investigated in a rotating disc column. The solvent was ethanol containing approximately 6% water. The influence of rotor speed, oil phase flow, and column geometry upon the dispersed phase holdup and the mass transfer efficiency was studied. The dispersed phase holdup increased with the increase of rotor speed and oil phase flow. Pratt's equation was used for calculating the characteristic velocity. An inverse relation was observed between the characteristic velocity and rotor speed, which is different from data previously reported in the literature. The estimated volumetric mass transfer coefficients increased as rotor speed and oil phase flow increased. The experimental results proved that it is feasible to obtain a refined oil with an oleic acid content less than 0.3 wt% by continuous solvent extraction. They also indicated that the corresponding loss of neutral oil was less than 5 wt%. Such value for the loss of neutral oil is significantly lower than the results reported in the literature for alkali or physical refining of corn oil.
Monitoring peroxide value in fatliquor manufacture by Fourier transform infrared spectroscopy
Authors: Ma Kangming , van de Voort F. R. , Ismail A. A. , Zhuo Hualong , Cheng Binjing
Published: November 2006

A Fourier transform infrared (FTIR) spectrometer equipped with an attenuated total reflectance (ATR) sample handling accessory was used to rapidly monitor the peroxide value (PV) of oils undergoing catalytic oxidation to produce sulfonated fatliquors used in the leather industry. PV quantitation was based on the stoichiometric reaction of triphenylphosphosphine (TPP) with hydroperoxides to produce triphenylphosphine oxide (TPPO). By using a germanium ATR accessory that has a very short effective pathlength, the spectral contributions of the base oil could be subtracted out, eliminating any oil‐dependent intereferences as well as providing a facile means of observing the spectral changes associated with the TPP/TPPO reaction. A calibration was devised by adding a constant amount of TPP‐saturated chloroform to oils containing varying amounts of tert‐butyl hydroperoxide (TBHP) to produce TPPO that had a measurable band at 1118 cm−1. this band was linearly related to TBHP concentration and the calibration devised had an SD of ∼3.4 PV over the range of 0–250 PV. The ATR‐PV method was standardized and the spectrometer programmed using Visual Basic to automate the analysis. the automated FTIR‐ATR method was found to be a convenient means of tracking PV of oils undergoing oxidation, and the results correlated well with the PV values obtained using the AOAC iodometric method (r=0.94). The FTIR‐ATR PV methodology provides a simple means of monitoring the PV of oils undergoing rapid oxidation and could serve as a quality‐control tool in the production of sulfonated oils for the leather industry.
Physical evaluation of pure zein films by atomic force microscopy and thermal mechanical analysis
Authors: Yoshino Tomoyuki , Isobe Seiichiro , Maekawa Takaaki
Published: November 2006

Biodegradable edible films can be made from corn protein, α‐zein. Pure zein films are cast from an organic solution of α‐zein. This report outlines the surface conditions of such pure zein films. First, the transition temperature, Tt′ of the pure zein film was measured with a thermomechanical analyzer. Tt was between 167.0 and 172.7°C. The thermal elongation of the films depended on the drying conditions used during film preparation. Second, the surface microstructure of pure zein films, produced under several different drying conditions, was observed by atomic force microscopy. The surface had a morphology that showed depressions either with acutely (90–120°) or obtusely (121–180°) angled features depending upon the drying conditions. On the other hand, the surface microstructure after thermal elongation analysis appeared to have a pattern of projections that was repeated every 25 nm. Third, we measured the contact angle of the pure zein films. We found a correlation between surface microstructure and contact angle. Pure zein films with projections smaller than 200 nm in base diameter on the surface had a high contact angle (>70°).
Fluorescence kinetics of soybean flour oxidation
Authors: Liang Jer‐Hour , Lin Chih‐Cheng
Published: November 2006

Changes in fluorescence and oxidation indices of soybean flour were studied during storage at 37, 50, and 60°C. The peroxide value and 2‐thiobarbituric acid value did not increase in proportion to the extent of oxidation. The front‐surface fluorescence of oxidized soybean flour had an excitation maximum around 350 nm and an emission maximum between 420 and 430 nm. The fluorescent compounds were soluble in the organic phase of chloroform/methanol (2∶1, vol/vol) after addition of water, and the solution showed excitation and emission maxima around 360 and 440 nm, respectively. The fluorescent compounds might have been produced from interactions of oxidizing soybean oil with other constituents of soybean flour. The fluorescence intensity in the organic phase increased steadily throughout the storage period. Fluorescence kinetics of soybean flour oxidation showed a zero‐order increase, and the rate followed an Arrhenius relationship with an activation energy of 47.8 kJ/mol. These results suggest that analysis of fluorescence intensity in the organic phase is a useful indicator for determination of the oxidative deterioration of soybean flour.