bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring interaction of β‐amyloid segment (25–35) with membrane models through paramagnetic probes
Authors: Esposito Cinzia , Tedeschi Annamaria , Scrima Mario , D'errico Gerardino , Ottaviani M. Francesca , Rovero Paolo , D'ursi Anna Maria
Published: November 2006

The accumulation of β‐amyloid peptides into senile plaques is one of the hallmarks of Alzheimer's disease (AD). There is mounting evidence that the lipid matrix of neuronal cell membranes plays an important role in the β‐sheet oligomerization process of β‐amyloid. Aβ(25–35), the sequence of which is GSNKGAIIGLM, is a highly toxic segment of amyloid β (Aβ)‐peptides, which forms fibrillary aggregates. In the present work, two spin‐labelled Aβ(25–35) analogues containing the nitroxide group of the amino acid TOAC (2,2,6,6‐tetramethylpiperidine‐1‐oxyl‐4‐amino‐4‐carboxylic acid) as a paramagnetic probe at the N‐ or the C‐terminus of the peptide sequence, respectively, were synthesized in order to investigate the peptide‐membrane interaction. The orientation and associated changes of the peptide conformation in the presence of different artificial membrane models (micelles, liposomes) were evaluated by electron paramagnetic resonance and circular dichroism techniques. The results of this study allowed us to propose a model in which the C‐terminal portion of the peptide is highly associated to the membrane, while the N‐terminal part extends into the aqueous phase with occasional contacts with the lipid head‐group region. Interestingly, the interaction of the C‐terminal portion of the peptide is particularly enhanced in the presence of sodium dodecyl sulfate (SDS) molecules. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Method for the synthesis of highly pure vaccines using the lipid core peptide system
Authors: Moyle Peter M. , Olive Colleen , Good Michael F. , Toth Istvan
Published: November 2006

Traditional vaccines consisting of whole attenuated microorganisms, killed microorganisms, or microbial components, administered with an adjuvant (e.g. alum), have been proved to be extremely successful. However, to develop new vaccines, or to improve upon current vaccines, new vaccine development techniques are required. Peptide vaccines offer the capacity to administer only the minimal microbial components necessary to elicit appropriate immune responses, minimizing the risk of vaccination associated adverse effects, and focusing the immune response toward important antigens. Peptide vaccines, however, are generally poorly immunogenic, necessitating administration with powerful, and potentially toxic adjuvants. The attachment of lipids to peptide antigens has been demonstrated as a potentially safe method for adjuvanting peptide epitopes. The lipid core peptide (LCP) system, which incorporates a lipidic adjuvant, carrier, and peptide epitopes into a single molecular entity, has been demonstrated to boost immunogenicity of attached peptide epitopes without the need for additional adjuvants. The synthesis of LCP systems normally yields a product that cannot be purified to homogeneity. The current study describes the development of methods for the synthesis of highly pure LCP analogs using native chemical ligation. Because of the highly lipophilic nature of the LCP lipid adjuvant, difficulties (e.g. poor solubility) were experienced with the ligation reactions. The addition of organic solvents to the ligation buffer solubilized lipidic species, but did not result in successful ligation reactions. In comparison, the addition of approximately 1% (w/v) sodium dodecyl sulfate (SDS) proved successful, enabling the synthesis of two highly pure, tri‐epitopic Streptococcus pyogenes LCP analogs. Subcutaneous immunization of B10.BR (H‐2k) mice with one of these vaccines, without the addition of any adjuvant, elicited high levels of systemic IgG antibodies against each of the incorporated peptides. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Effects of N‐ and C‐terminal addition of oligolysines or native loop residues on the biophysical properties of transmembrane domain peptides from a G‐protein coupled receptor
Authors: Cano‐Sanchez Patricia , Severino Beatrice , Sureshbabu V. V. , Russo Joe , Inui Tatsuya , Ding Fa‐Xiang , Arshava Boris , Becker Jeff , Naider Fred
Published: November 2006

Transmembrane domains (TMDs) of G‐protein coupled receptors (GPCRs) have very low water solubility and often aggregate during purification and biophysical investigations. To circumvent this problem many laboratories add oligolysines to the N‐ and C‐termini of peptides that correspond to a TMD. To systematically evaluate the effect of the oligolysines on the biophysical properties of a TMD we synthesized 21 peptides corresponding to either the second (TPIFIINQVSLFLIILHSALYFKY) or sixth (SFHILLIMSSQSLLVPSIIFILAYSLK) TMD of Ste2p, a GPCR from Saccharomyces cerevisiae. Added to the termini of these peptides were either Lysn (n = 1,2,3) or the corresponding native loop residues. The biophysical properties of the peptides were investigated by circular dichroism (CD) spectroscopy in trifluoroethanol–water mixtures, sodium dodecyl sulfate (SDS) micelles and dimyristoylphosphocholine (DMPC)‐dimyristoylphosphoglycerol (DMPG) vesicles, and by attenuated total reflection Fourier transform infrared (ATR‐FTIR) in DMPC/DMPG multilayers. The results show that the conformation assumed depends on the number of lysine residues and the sequence of the TMD. Identical peptides with native or an equal number of lysine residues exhibited different biophysical properties and structural tendencies. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Probing DNA–peptide interaction forces at the single‐molecule level
Authors: Sewald Norbert , Wilking Sven D. , Eckel Rainer , Albu Silvia , Wollschläger Katrin , Gaus Katharina , Becker Anke , Bartels Frank W. , Ros Robert , Anselmetti Dario
Published: November 2006

The versatility of chemical peptide synthesis combined with the high sensitivity of AFM single‐molecule force spectroscopy allows us to investigate, quantify, and control molecular recognition processes (molecular nanotechnology), offering a tremendous potential in chemical biology.

Single‐molecule force spectroscopy experiments are able to detect fast intermediate transition states, details of the energy landscape, and structural changes, while avoiding multiple binding events that can occur under ensemble conditions. Dynamic force spectroscopy (DFS) is even able to provide data on the complex lifetime. This minireview outlines the biophysical methodology, discusses different experimental set‐ups, and presents representative results in the form of two case studies, both dealing with DNA‐binding peptides. They may serve as model systems, e.g., for transcription factors or gene transfection agents. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Aldehyde modification of peptide immunogen enhances protein‐reactive antibody response to toxic shock syndrome toxin‐1
Authors: Bavoso Alfonso , Ostuni Angela , De Vendel Jolanda , Pollaro Francesco , Armentano Francesca , Knight Thomas , Makker Sudesh , Tramontano Alfonso
Published: November 2006

Introduction of aldehyde groups into protein conjugates enhanced the immune response to a coupled peptide without the use of strong adjuvants. Synthetic peptides representing the N‐terminal (residues 1–16) and internal (residues 53–65) epitopes of toxic shock syndrome toxin‐1 (TSST‐1) were coupled to carrier protein, and carbonyl tags were introduced by Amadori reaction with glycolaldehyde. Modified and unmodified antigens in alum were used to immunize rabbits and the reactivities of antisera were compared. Aldehyde modification augmented the response detected by ELISA, which included enhanced binding to peptides and to native TSST‐1. In western blot, TSST‐1 was detected by antiserum elicited to the N‐terminal peptide, but not that generated to the peptide representing the internal sequence. The same antiserum also neutralized TSST‐1 activity in a lymphocyte proliferation assay. The circular dichroism spectrum of the N‐terminal peptide indicated a propensity for helical conformation, similar to the structure at the corresponding sequence of the native protein. These data suggest that aldehyde modification can boost immunogenicity of peptide‐based vaccines, generating epitope‐specific immune responses against the cognate protein antigens without using potent adjuvants. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Raman spectroscopy under pressure in semiconductor nanoparticles
Authors: Weinstein B. A.
Published: November 2006

A brief survey of recent high‐pressure Raman investigations and associated studies of nanoparticle systems is given, and the consequences for understanding the vibrational properties and stability of these systems are reviewed. The results of new pressure‐Raman experiments on colloidal ZnSe nanorods, high‐purity bulk 68Zn76Se crystals, and colloidal InP/CdS core/shell nanoparticles are presented. The nanorod and bulk ZnSe spectra are compared for similar pressure cycles. Evidence is found for the early stages of nucleation of the zincblende‐rocksalt transition in the bulk crystals, and for the effects of non‐uniform surface contact forces in the nanorod ensemble. Similarities and differences between the post‐transition spectra of both types of samples are discussed. The InP/CdS core/shell nanoparticles exhibit a structured Raman line‐shape that contains contributions from LO‐ and TO‐like modes of the InP cores and from an overlapping manifold of CdS shell modes. Our results indicate that pressure acts to decrease this overlap. Cross‐interface mechanical coupling is considered for describing the pressure‐induced line‐shape changes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Teaching science in museums: The pedagogy and goals of museum educators
Authors: Tran Lynn Uyen
Published: November 2006

Museum educators have a longstanding presence in museums and play a significant role in the institutions' educational agenda. However, research on field trips to science museums has predominantly explored teachers' and students' perspectives with little acknowledgment of the museum educators who develop and implement the educational programs the students experience. This study sought to describe instruction undertaken in, and goals driving, science museums' lessons through observations of museum educators followed by conversations with them immediately afterwards. Findings showed the ways in which educators adapted their preplanned lessons to the students' interests, needs, and understanding by manipulating the sequence and timing. The data revealed that, contrary to depictions in the research literature of teaching in museums as didactic and lecture oriented, there was creativity, complexity, and skills involved in teaching science in museums. Finally, the educators' teaching actions were predominantly influenced by their affective goals to nurture interests in science and learning. Although their lessons were ephemeral experiences, these educators operated from a perspective, which regarded a school field trip to the science museum, not as a one‐time event, but as part of a continuum of visiting such institutions well beyond school and childhood. These findings have implications for the pedagogical practices employed by museum educators, and the relationship between teachers and educators during school field trips, which are discussed. © 2006 Wiley Periodicals, Inc. Sci Ed 91:278–297, 2007
Measurement of sputtering yields and damage in C60 SIMS depth profiling of model organic materials
Authors: Shard A. G. , Brewer P. J. , Green F. M. , Gilmore I. S.
Published: November 2006

Sputter‐depth profiles of model organic thin films on silicon using C60 primary ions have been employed to measure sputtering yields and depth resolution parameters. We demonstrate that some materials (polylactide, Irganox 1010) have a constant and high sputtering yield, which varies linearly with the primary ion energy, whereas another material (Alq3) has lower, fluence‐dependent sputtering yields. Analysis of multi‐layered organic thin films reveals that the depth resolution is a function of both primary ion energy and depth, and the sputtering yield depends on the history of sputtering. We also show that ∼30% of repeat units are damaged in the steady‐state regime during polylactide sputtering. Crown Copyright © 2006. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
Studies on the role of phospholipids in the triglyceride cycle: II. Turnover of plasma phospholipids in ethionine‐treated dogs
Authors: Olmsted C. A.
Published: November 2006

The disappearance of native labeled plasma phospholipids (nPLP32) was abruptly halted in the plasma of normal mongrel dogs shortly after givingdl‐ethionine by intraperitoneal injection. In other dogs, chronic feeding of ethionine over a period of three days prior to these measurements prolonged the turnover time of plasma phospholipids. This impairment in the turnover of plasma PL brought about by ethionine administration occurs regardless of sex differences in lipid metabolism or other physiological differences relating to the nutritional status of the animal. The amount of nPLP32 found in the liver at the end of the turnover experiments was also measured. These data suggest that phospholipid transport from plasma to liver is not impaired by ethionine. The possible significance of an ethionine‐induced choline deficiency which impairs transport of triglycerides and phospholipids from the liver to plasma is considered in regard to the role of phospholipids in the triglyceride cycle.
Mass spectrometry of long‐chain aliphatic aldehydes, dimethyl acetals and Alk‐1‐enyl ethers
Authors: Christiansen Kirsten , Mahadevan V. , Viswanathan C. V. , Holman R. T.
Published: November 2006

Mass spectra of long‐chain saturated and unsaturated aliphatic aldehydes, dimethyl acetals and alk‐1‐enyl methyl ethers are reported and discussed. Using deuterium labeled aldehydes, knowledge about the mass spectral fragmentation is obtained. The m/e M‐44 ion is formed by a rearrangement different from the mechanism postulated previously for short‐chain aldehydes. A series of hydrocarbon fragments with even mass numbers of 68+14n (n=0,1,2...) appear in the spectra of all three series of compounds.
The lipids of mitochondria of human gray and white matter
Authors: Gerstl B. , Eng L. F. , Hayman R. B. , Bond P.
Published: November 2006

Mitochondrial enriched fractions were obtained separately from gray and white matter of human and bovine brains. The preparations differed in that choline and ethanolamine glycerophosphatides were present in higher concentration in mitochondria than in gray or white matter from which they were derived. The fatty acid composition also was at variance, palmitic, palmitoleic and linoleic acids being present in considerably higher concentration in the mitochondria of white matter than in the corresponding homogenate, and fatty acids of C25 and C26 chain length being absent. A deficiency of polyunsaturated fatty acids and the lowest linoleic acid were found in a preparation obtained from a multiple sclerosis brain, a lesser deficiency was noted in the preparation from an emaciated individual.
Reaction of lipoxidase with polyenoic acids in marine oils
Authors: Beare‐Rogers Joyce L. , Ackman R. G.
Published: November 2006

Eight samples of raw oils from fresh water and marine fish, and two from marine mammals, were examined for polyenoic fatty acids susceptible to the action of lipoxidase. The results agreed well in most instances with gas chromatographic data and indicated that only one peroxide group was formed in polyenoic fatty acids with more than one ostensibly suitable 1,4‐pentadiene system. Four commercially available preparations of polyenoic fatty acids showed varying degrees of susceptibility to lipoxidase, indicating the probable presence of artifacts formed in purification steps. The marine polyenoic acids were suitable substrates for lipoxidase.
Acceleration and inhibition of lipid oxidation by heme compounds
Authors: Kendrick Jean , Watts Betty M.
Published: November 2006

The acceleration and inhibition of unsaturated fatty acid oxidation by heme compounds was followed in model systems with an oxygen analyzer. The linoleate to heme molar ratios for maximum catalysis were 100 for hemin and catalase, 250 for metmyoglobin, 400 for cytochrome c and 500 for methemoglobin. With heme concentrations of 2 to 4 times the optimum catalytic amount, no oxidation occurred. Rapid heme destruction was observed with catalyzing ratios of lipid to heme, but with inhibitory ratios a stable red compound formed, believed to be a lipid hydroperoxide derivative of the heme. The ratios of lipid to metmyoglobin for maximum acceleration varied with the pH. Linolenate was much less sensitive to heme catalysis than linoleate. Colorless products of heme degradation had a marked antioxidant effect. A possible mechanism for the antioxidant effect of hemes is advanced, based on the formation of stable heme peroxide complexes or stable heme radicals, or both, during the early stages of oxidation. Prooxidant activity is believed to occur only when the peroxide to heme ratio is so high that the oxidation of the hemes goes beyond the initial stages.
Teucrium depressum seed oil: A new source of fatty acids with Δ‐‐unsaturation
Authors: Smith C. R. , Freidinger R. M. , Hagemann J. W. , Spencer G. F. , Wolff I. A.
Published: November 2006

The seed oil ofTeucrium depressum Small yields two unusual trienoid components, all‐cis‐5,9,12‐octadecatrienoic acid (6.7%) andtrans‐5,cis‐9,cis‐12‐octadecatrienoic acid (2.0%). A third unusual component, identified ascis‐5,cis‐9‐octadecadienoic acid, also occurs in this oil as a trace constituent.
Glyceride structure ofErlangea tomentosa seed oil, a new source of vernolic acid
Authors: Phillips B. E. , Smith C. R. , Hagemann J. W.
Published: November 2006

(+)‐Methyl vernolate constitutes 52% of the methyl esters formed by transmethylating the oil ofErlangea tomentosa seed. Thin layer chromatography fractionated the oil into trivernolin, divernolins, monovernolins and nonvernolate glycerides. Pancreatic lipolyses of the monovernolins and the divernolins followed by transmethylation of the monoglycerides indicated the presence of 34 vernolate glycerides above the 0.1% level, grouped as follows: α‐monovernolins, 15%; β‐monovernolins, 3%; α,α′‐divernolins, 10%; α,β‐divernolins, 37%; trivernolin, 16%; and nonvernolate glycerides, 19%.
Essential fatty acid‐deficient rats: I. Growth and testes development
Authors: Aaes‐Jørgensen E. , Hølmer G.
Published: November 2006

Partially hydrogenated oils as the sole dietary fat enhances the development of essential fatty acid (EFA) deficiency in young rats. Partially hydrogenated herring oil (HHO) caused total impairment of the spermatogenic tissue after five weeks of experiment, while partially hydrogenated arachis oil (HAO) caused severe degeneration of this tissue in 15 weeks. A fat‐free diet caused degeneration in 26 weeks. In the dietary fats, the total content oftrans acids, calculated as elaidic acid, was 47% and 23% in HAO and HHO, respectively. Further, varying amounts of different positional isomeric fatty acids were also present in the partially hydrogenated oils. Besides the specific tissue changes, poor growth, poor feed efficiency and skin signs characteristic of EFA deficiency were noticed. On the other hand, partially hydrogenated soybean oil (HSO) as the sole dietary fat kept the animals normal in all respects. this oil still contained 32% linoleic acid; the total content oftrans acids amounted to 11%, calculated as elaidic acid.
Phase relationships involving the deposition of cholesterol from triglyceride solution
Authors: Wright Lemuel D. , Gaylor J. L.
Published: November 2006

Adsorption isotherms describing the adsorption of cholesterol from solution in various oils by Permutit were investigated. Multiple layer adsorption onto Permutit and cholesterol crystallization from solutions that would have been subsaturated with respect to cholesterol in the absence of Permutit were observed. Association of cholesterol with Permutit, required for multiple layer adsorption, was observed even at low concentrations of cholesterol. Near infrared absorption spectra of solutions of cholesterol revealed marked aggregation of cholesterol in solutions of greater than about 0.2 M. Thus, association with Permutit apparently initiates crystallization and the similar aggregation of cholesterol in solution and in the solid phase apparently propagates the crystallization of cholesterol. Hydrogen bonding of cholesterol to the ester bond of triglycerides is unrelated to solubility of cholesterol in triglycerides examined.
The effect of aging of human red cells in vivo on their fatty acid composition
Authors: Phillips Gerald B. , Dodge James T. , Howe Calderon
Published: November 2006

Using improved methods for fatty acid analysis and a density gradient method for separation of red cells according to age, we analyzed the fatty acid composition of a young fraction and an old fraction of red cells from each of seven normal subjects and from one patient with polycythemia vera. Twenty‐four fatty acid peaks were quantified. The individual phospholipid composition of both fractions was determined in the red cells of two normal sujects. Statistically significant changes in the relative amounts of major fatty acids were observed with red cell aging. Furthermore, a pattern of change was evident in that the relative amounts of four of the five fatty acids of C18 or shorter chain length showed an increase and all 19 fatty acids of C20 or longer chain length showed a decrease with red cell aging. While the change with aging in every fatty acid peak was not statistically significant, the consistency in the direction of the change in the fatty acids of C20 or longer chain length was highly significant. A suggested change in the distribution of the major phospholipid groups with red cell aging did not appear to explain completely the changes in fatty acids.
Gas liquid chromatographic analysis of sphingosine bases in sphingolipids of human normal and multiple sclerosis cerebral white matter
Authors: Moscatelli Ezio A. , Isaacson Elizabeth
Published: November 2006

Sphingomyelins, cerebrosides and sulfatides were isolated from white matter of human normal and multiple sclerotic brain. Column chromatography was used for class separations, which were monitored by thin layer chromatography. Acid‐catalyzed methanolysis, followed by isolation of bases and gas liquid chromatography of periodate‐produced aldehydes, was used to determine sphingosine base composition of each sphingolipid. Reflux methanolysis (where HCl=2 N) was used for cerebrosides and sulfatides, but could not be used for reliable sphingomyelin base analysis, for which sealed‐tube methanolysis at 70–80 C (where HCl=1 N) was used. Our results suggest there is little, if any, difference in sphingosine base chain‐length distribution among the sphingolipids analyzed.
Specific distribution of fatty acids in the milk fat triglycerides of goat and sheep
Authors: Marai L. , Breckenridge W. C. , Kuksis A.
Published: November 2006

The triglycerides of the fat globules of sheep and goat milk were isolated and separated into short and long chain lengths by silicic acid column chromatography. The short chain lengths comprised major triglycerides with 34–44 acyl carbon atoms and accounted for nearly 50% of the total milk fat. The long chain lengths contained major triglycerides with 40–54 acyl carbons. Stereospecific analyses of the short chain triglyceride fraction showed that of the 20–23 moles per cent of C4−C8 fatty acids present, at least 95% were specifically attached to the glycerol molecule in the position corresponding to carbon 3 ofsn‐glycerol. The distribution of the other fatty acids (C10 or greater) did not show such marked specificity for either the 1 or the 2 position. Although individual triglycerides were not identified, the specific placement of the fatty acids could best the accounted for by assuming a common pool of long chain 1,2‐diglycerides which served as precursors of the bulk of both short and long chain triglycerides during milk fat synthesis.
Species variations in phospholipid class distribution of organs: II. Heart and skeletal muscle
Authors: Simon Gerald , Rouser George
Published: November 2006

Total lipid, lipid phosphorus and phospholipid class distribution were determined for heart and skeletal muscles from five vertebrates (human, bovine, rat, mouse and frog) and skeletal muscles from four invertebrates (lobster, abalone, scallop and sea urchin). The precision of the analytical method [separation by two‐dimensional thin layer chromatography (TLC) and phosphorus analysis of spots] was demonstrated by small values for standard deviations. Accuracy of spot identification and analytical values was insured by comparison with results obtained by TLC of triethylaminoethyl cellulose column chromatographic fractions. Values for total lipid, total phospholipid and phospholipid class distribution of heart and skeletal muscles from the five vertebrate species showed essentially the same variability observed for the same organ from different animals of one species (rat). The data indicate that, among vertebrates there is little or no variability for phospholipid class distribution in muscle membranes in agreement with data for other organs and subcellular particulates presented in other reports. Invertebrate skeletal muscles were found to differ qualitatively and/or quantitatively from those of vertebrates. In one species (sea urchin), ceramide phosphorylethanolamine was the only sphingolipid, sphingomyelin characteristic of vertebrates being absent. In two species (abalone and scallop) ceramide aminoethylphosphonate was present and sphingomyelin was absent. In one (lobster), sphingomyelin was the only sphingolipid. Quantitatively, higher levels of sphingolipid and phosphatidyl serine and lower levels of phosphatidyl inositol were found in invertebrate skeletal muscle. The significance of the data is discussed in relation to subcellular particulate lipid class composition.
Hepatic metabolism of 1‐14C octanoic and 1‐14C margaric acids
Authors: Boyer James L. , Scheig Robert
Published: November 2006

The hepatic metabolism of 1‐14C margaric acid, a 17 carbon long chain saturated fatty acid which is present in the liver in trace amounts, was compared with 1‐14C octanoic acid and 1‐14C palmitic acid to determine if the enhanced oxidation of medium chain fatty acids to CO2 was dependent on fatty acid chain length or the endogenous pool size of the fatty acid substrate. Despite the fact that endogenous margarate is present in trace amounts, there was no significant difference in the oxidation of margarate and palmitate to CO2, while the oxidation of octanoate to CO2 was significantly more rapid. Both margarate and palmitate were more readily incorporated into lipid soluble products in contrast to the low rate of incorporation of octanoate. However, margarate was less readily incorporated into triglyceride, phospholipid and monoglyceride than palmitate. These studies suggest that the chain length rather than hepatic content of the fatty acid determines whether the carboxyl group of equimolar amounts of a 1‐14C‐carboxyl labeled fatty acid will be preferentially oxidized to CO2 or incorporated into tissue lipid in the liver.
Reciprocal interactions in the desaturation of linoleic acid into γ‐linolenic and eicosa‐8,11,14‐trienoic into arachidonic
Authors: Brenner R. R.
Published: November 2006

Variable concentrations of [I14C] linoleic acid and [I14C] eicosa‐8,11,14‐trienoic acid were incubated with liver microsomes in a medium containing the necessary cofactors for fatty acid desaturation. The conversion of linoleic into γ‐linolenic acid and eicosatrienoic into arachidonic acid were mutually inhibited and the inhibition depended on the concentration of the fatty acids incubated.
Phospholipid class and fatty acid composition of developing spinal cord in normal pigs and in congenital tremor (Myoclonia congenita)
Authors: Berry James F. , Fletcher Thomas F. , Bovis Magdaline
Published: November 2006

Extracts of spinal cord lipids from normal pigs and littermates affected with myoclonia congenita were examined for lipid and fatty acid composition at 6, 10, 14, 21 and 30 days of age. A marked decrease in total crude lipid and in phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS) and phosphatidylinositol (PI) occurred in spinal cord lipids of affected pigs. Cholesterol esters were absent from spinal and lipid extracts and no qualitative difference in ganglioside patterns were observed between normal and affected pigs at any age. Spinal cord lipid extracts from affected pigs had less oleic acid except at 30 days and more arachidonic, docosapentaenoic and docosahexaenoic acids than normal.
The determination ofTrans isomers in GLC fractions of unsaturated esters
Authors: Allen Robert R.
Published: November 2006

The determination of the amount oftrans unsaturated isomers present in collected fractions of unsaturated fatty acid methyl esters separated by gas liquid chromatography is accomplished by measuring the infrared absorbances of the collected peak at 10.36 and 8.55 μ. The ratio of these two absorbances is proportional to thetrans unsaturation. The interfering polyester column bleed is removed from the collected peaks by collection on alumina and elution into the spectrophotometer cell with CS2.
Evidence for acyl transfer reactions between neutral glycerolipids in dogfish (Squalus acanthias) serum
Authors: Malins Donald C. , Robisch Paul A.
Published: November 2006

Radioactively labeled triacylglycerols, 1,3‐dioleoyl‐2‐[1‐14C]‐palmitoylglycerol and 1,3‐[9,10‐3H]‐dioleoyl‐2‐palmitoylglycerol, were incubated with dogfish (Squalus acanthias) serum for periods of up to 10.0 hr. Changes in the positional distributions of carbon‐14 and tritium within the triacylglycerols in 5.0 hr and 10.0 hr indicate that intermolecular and intramolecular shifts occur among the fatty acids. In addition, a maximum of 8.3% of the carbon‐14 and 5.9% of the tritium was incorporated into 1‐alkyl‐2,3‐diacylglycerols; essentially all of this incorporated radioactivity was associated with the acyl chains in the 1.5 and 5.0 hr incubations. In the 10.0 hr incubations, however, 25% of the tritium incorporated into the 1‐alkyl‐2,3‐diacylglycerols was associated with the 0‐alkyl chains. Radioactivity was not incorporated significantly into free fatty acids in the 1.5 and 5.0 hr incubations. These results indicate that acyl transfer reactions take place among molecular species of triacylglycerols, as well as between triacylglycerols and 1‐alkyl‐2,3‐diacylglycerols. In the latter case, the conversions appear to be operative in the virtual absence of net biosynthesis.
On extraction of acyl and alkyl dihydroxyacetone phosphate from incubation mixtures
Authors: Hajra Amiya K.
Published: November 2006

Chloroform‐methanol mixture was shown to extract acyl and alkyl dihydroxyacetone phosphate from enzyme incubation mixtures. However, when the lipid extract was washed with water to remove nonlipid materials, 70–80% of acyl and alkyl dihydroxyacetone phosphate were lost in the aqueous phase. It was shown that, keeping the pH low (<2.5) during the partition of lipids by the Bligh and Dyer method, most (>95%) of the acyl and alkyl dihydroxyacetone phosphate were recovered in the chloroform‐rich phase. n‐Butanol was shown to extract 80–90% of these lipids from incubation mixtures at neutral pH.
Effects of chronic ethanol ingestion upon acyl‐CoA: Carnitine acyltransferase in liver and heart
Authors: Parker Sharon L. , Thompson John A. , Reitz Ronald C.
Published: November 2006

Chronic alcohol ingestion has been shown to cause a profound decrease in the activity of acyl‐coenzymeA:carnitine acyltransferase in the liver. Twelve diferent acyl‐coenzymes were used as substrates, and the decrease in acyltranser rates ranged from 22–60% of the control. This enzyme was not affected as drastically in the heart. Of 11 acyl‐coenzymes tested, only two resulted in significantly lower rates of acyltransfer, even though the rates were decreased with all substrates tested. The specificities of this enzyme showed that increasing the chain length of the acyl group resulted in a decreased acyltransfer when the acyl groups were either saturated, monoenoic, dienoic, or trienoic. Also, increasing the number of ethylenic bonds present in the acyl group of fatty acyl‐coenzymes of the same chain length resulted in increased rates of acyltransfer. One exception to this ethylenic bond effect was noted in the heart. Linolenate resulted in an acyl‐transfer rate lower than linoleate. Ethanol had little or no effect upon these specificities.
Effects of age, sex, and diet upon carcass and liver fatty acid composition of pitman‐moore miniature pigs
Authors: Filer L. J. , Fomon Samuel J. , Anderson Thomas A. , Nixt Thomas L. , Andersen Dean W.
Published: November 2006

Fatty acid composition of carcass and liver and proximate analysis of liver were studied in 14–28 day old Pitman‐Moore miniature pigs, 26 sow‐reared and 30 fed a semisynthetic diet in which the fat was lard. With increasing age, fat of carcass, but not of liver, became significantly more unsaturated. The percentage of palmitic acid (16∶0) and total saturated fatty acids was significantly greater and the percentage of linoleic acid (18∶2) and total unsaturated fatty acids significantly less in carcasses of male than of female pigs. No sex‐related differences in proximate or fatty acid composition of the liver were noted. Carcasses of sow‐reared pigs contained significantly greater percentages of myristic (14∶0), palmitoleic (16∶1), and linoleic acids and significantly lesser percentages of stearic (18∶0) and oleic (18∶1) acids than did those of pigs fed the semisynthetic diet. Diet‐related differences in fatty acid composition of liver closely paralleled those of carcass, although liver contained markedly greater percentages of stearic and arachidonic (20∶4) acids and lesser percentages of palmitoleic and oleic acids than did carcass. Diet‐related differences in fatty acid composition of carcass and liver are discussed in relation to the fatty acid composition of dietary fat (sow milk and lard).
Isovaleric acid as a precursor of odd numbered iso fatty acids in Tetrahymena
Authors: Conner Robert L. , Koo Kim‐Eng , Landrey J. R.
Published: November 2006

Tris isovalerate‐supplementedTetrahymena pyriformis W showed no qualitative change in fatty acid composition; however, an increase in polar lipids that contain odd numbered iso acids (C13, C15, C17, C19) occurred. This change was accompanied by a decrease in the proportional amount of even numbered normal acids (C14, C16, C18). The neutral and polar lipids from cells incubated with [1‐14C] isovaleric acid were found to contain radioactivity. The methyl esters of the saturated fatty acids obtained from the polar lipids by alkaline methanolysis were separated by reversed phase chromatography, the identities confirmed by gas chromatography‐mass spectrometry, and the specific activities determined. Iso acids were found to be the most heavily labeled materials. In addition to ceramide, two sphingolipid components were detected. One yielded saturated fatty acids after acidic methanolysis, while the other contained >93% α‐hydroxy fatty acids. Radioactivity was noted in the long chain base fraction derived from the sphingolipids. Progressive growth inhibition occurred as the isovalerate concentration was increased in the culture medium; however, the ciliates were morphologically indistinguishable from unsupplemented cells.
Effects of triparanol and AY‐9944 upon sterol biosynthesis inChlorella
Authors: Patterson G. W. , Doyle P. J. , Dickson L. G. , Chan J. T.
Published: November 2006

The growth rates of three species ofChlorella were inhibited by triparanol and AY‐9944.Chlorella emersonii was noticeably more resistant to both inhibitors than the other species. A large number of sterols were isolated and identified in inhibited cultures. Ca. 18 of these were identified from nature for the first time. Triparanol resulted in inhibition of the removal of the 14α methyl group. It also inhibited the second alkylation of the side chain and, in one species, strongly inhibited the Δ8 → Δ7 isomerase reaction. InC. ellipsoidea, triparanol also inhibited Δ14‐reductase and Δ7‐reductase. The introduction of the Δ22 double bond was inhibited by both drugs. The effect of AY‐9944 was similar to that of triparanol inC. emersonii, but it was an extremely effective Δ14‐reductase inhibitor inC. ellipsoidea. These various types of inhibition of sterol synthesis indicate a lack of specificity of both drugs inChlorella and suggest that primitive plants such as these may be valuable as test organisms in an evaluation of the activity of potential inhibitors of sterol biosynthesis.
Distribution of sterols in the fungi I. Fungal spores
Authors: Weete John D. , Laseter John L.
Published: November 2006

The freely extractable sterols of spores ofLinderina pennispora, Spicaria elegans, Penicillium claviforme, Aspergillus niger, Ustilago nuda, U. maydis, Puccinia graminis, andP. striiformis were examined using mass spectrometric techniques. Each species contained at least 3–5 detectable sterol components in the 4‐desmethyl sterol fraction, and, when present, ergosterol was generally the most abundant sterol produced by an individual species. Smaller relative concentrations of fungisterol (ergost‐Δ7‐enol) di‐ and tetraunsaturated C28 sterols also were found. In some species, fungisterol was the most abundant sterol. In uredospores of rust fungi, stigmast‐Δ7‐enol (C29) was predominant and was accompanied by lower relative concentrations of a diunsaturated C29 sterol and fungisterol. Cholesterol was found only in the teliospores of the corn smut fungus (U. maydis). Application of glass capillary columns to the separation of yeast sterols by gas liquid chromatography is illustrated.
Phytosterol side chain biosynthesis
Authors: Goad L. J. , Lenton J. R. , Knapp F. F. , Goodwin T. W.
Published: November 2006

The typical plant sterols contain a substituent at C‐24 of the side chain. This can be a methylene, ethylidene, methyl, or ethyl group; with the last three groups, all possible isomers have been reported in nature. The C‐24 alkyl groups are derived by a transmethylation reaction from methionine. The details of several distinct alkylation mechanisms, which are now recognized in a range of lower and higher plants, have been reviewed. The operation of these different routes may have some phylogenetic significance.
Role of sterols in membranes
Authors: Nes Williams R.
Published: November 2006

Sterols, or in rare cases structurally similar molecules, are biosynthesized or at least required by all eucaryotic organisms, as well as by many procaryotic ones, regardless of their status as plants, animals, or protista. This information, together with quantitative, structural, metabolic, and other data is reviewed. It is interpreted to mean that the primary role sterols play in nature is a nonmetabolic one as architectural components of membranes and that this role can be played, but less well, by other molecules which approximate the steroidal structure. The biosynthetic process should, therefore, and actually does not appear to be correlatable with this role, which, in turn, is correlatable with phylogenesis. The Δ24‐reduction‐alkylation bifurcation, for instance appears to be interrelated profoundly with the evolutionary differentiation of the animal from the plant kingdom.
Function of steryl esters in plants: A hypothesis that liquid crystalline properties of some steryl esters may be significant in plant sterol metabolism
Authors: Atallah A. M. , Nicholas H. J.
Published: November 2006

The synthesis of a wide variety of desmethyl, 4α‐ and 4,4‐dimethyl steryl esters, whose physical properties have been described elsewhere, has indicated that side chain structure and the position of a double bond in the nucleus are critical in determining whether or not a steryl ester can form a mesophase (liquid crystalline state). Since the capability of mesophase formation seems rather specifically distributed in the biosynthetic steps leading to the formation of animal, plant, and fungal sterols, the hypothesis is presented that such mesophase formation, or lack of it, may control the biosynthetic sequence by virtue of the viscosity changes associated with the formation of liquid crystals. Mesophase formation of thermotropic liquid crystals is influenced by a number of physical factors, including heat, electrical current, pressure, and impurities, e.g. solvents. Some preliminary experiments with incubation of cell‐free extracts ofPhaseolus vulgaris are reported, with heat as the physical parameter studied, following the addition of cholesteryl‐1,2‐3H, sitosteryl‐22,23‐3H(N) palmitates, and the respective free compounds to the cell‐free extracts. Although some possible influence of heat during the incubation of the compounds upon their distribution in subcellular fractions was indicated, no consistent pattern was found. However, some observations on the capability of the subcellular organelles to hydrolyze the added esters and esterify the free compounds are presented. The data suggest that hydrolysis of steryl esters and their synthesis by plant cell‐free extracts are both of more than coincidental occurrence.
Improved synthesis of 7‐dehydrositosterol
Authors: Kircher Henry W.
Published: November 2006

Sitosteryl acetate was brominated in petroleum ether by the gradual addition of N‐bromosuccinimide to a refluxing, illuminated solution and dehydrobrominated by the dropwise addition of the bromo derivative to a refluxing solution of collidine in mesitylene to give a 38% yield of 7‐dehydrositosteryl acetate.
Location of double bonds in long chain esters by methoxymercuration‐demercuration followed by mass spectroscopy
Authors: Minnikin D. E. , Abley P. , McQuillin F. J. , Kusamran K. , Maskens K. , Polgar N.
Published: November 2006

Methyl esters of simple mono‐, di‐, and triunsaturated long chain fatty acids quantitatively react with mercuric acetate in methanol to produce methoxyacetoxymercuri derivatives. Demercuration of these derivatives with sodium borohydride yields methoxylated fatty acid esters, readily isolable by thin layer chromatography. Mass spectra of the methoxylated esters are characterized by intense peaks due to cleavage adjacent to methoxy‐functions which allow the position of the original double bond in the chain to be ascertained. The methoxylated derivatives are conveniently analyzed by gas liquid chrovmatography and also by combined gas chromatographymass spectrometry. In comparison with other methods for double bond location, the procedure described in simple, reliable, and rapid.
Characteristics of the lipase from the mold,Geotrichum candidum: A review
Authors: Jensen Robert G.
Published: November 2006

The moldGeotrichum candidum produces an extracellular lipase, readily concentrated by removal of the culture medium in which the microorganism is grown. The lipase is characterized by a unique, but not absolute, specificity for fatty acids containingcis‐9 orcis,cis‐9, 12 unsaturation, hydrolyzing both regardless of position within the triglyceride molecule. The enzyme also hydrolyzescis‐9‐16∶1,cis,trans‐9,12‐18∶2,trans,cis‐9,12‐18∶2, palmitoyl oleate and cholesteryl oleate. Digested at comparatively slow rates are:trans,trans‐9,12‐18∶2, double bond positional isomers of 18∶1 (other thancis‐9), stearolic acid, oleoylpalmitate, dilinoleoyl phosphatidyl choline, and saturated acids. The enzyme has an optimum pH of 8.2, and the lyophilized powder is extremely stable, retaining activity for at least eight years when stored at‐20 C. A purification of 81‐fold has been achieved.
Sterols, methylsterols, and triterpene alcohols in threeTheaceae and some other vegetable oils
Authors: Itoh Toshihiro , Tamura Toshitake , Matsumoto Taro
Published: November 2006

The unsaponifiables from threeTheaceae (Camellia japonica L.,Camellia Sasanqua Thunb., andThea sinensis L.) oils and alfalfa, garden balsam, and spinach seed oils and shea fat were separated into four fractions: sterols, 4‐methylsterols, triterpene alcohols, and less polar compounds by thin layer chromatography. While the sterol fraction was the major one for the unsaponifiables from alfalfa and spinach seed oils, the triterpene alcohol fraction was predominant for the unsaponifiables from all other oils. The sterol, 4‐methylsterol, and triterpene alcohol fractions were analyzed by gas chromatography. All the sterol fractions were alike in their compositions, consisting exclusively of Δ7‐sterols, such as α‐spinasterol and Δ7‐stigmastenol as predominant components together with Δ7‐avenasterol and 24‐methylcholest‐7‐enol. Obtusifoliol, gramisterol (occasionally accompanied with cycloeucalenol), and citrostadienol, together with several other unidentified components, were found in the 4‐methylsterol fractions from all of the oils except shea fat. The 4‐methylsterol fraction from shea fat showed a characteristic composition containing a large proportion of unidentified components which had relative retention time greater than that of citrostadienol, while no citrostadienol was detected. β‐Amyrin, lupeol, and butyospermol were major components of the triterpene alcohol fractions from most of the oils, but the fraction from spinach seed oil contained cycloartenol and 24‐methylene‐cycloartanol as predominant components. There is a close similarity in the compositions of unsaponifiables (sterols, 4‐methylsterols, and triterpene alcohols) of the threeTheaceae oils. Two sterols, α‐spinasterol and Δ7‐stigmastenol, and five triterpene alcohols were isolated from tea seed oil. Moreover, five unidentified components beside parkeol, butyrospermol, α‐amyrin, and lupeol were isolated from the triterpene alcohol fraction of shea fat.
Modification of in vitro rat adrenal corticosteroidogenesis by dietary fat
Authors: Egwim Peter O. , Kummerow F. A.
Published: November 2006

Three groups of male weanling Holtzman rats were maintained, ad libitum, for 4 and 8 weeks on 1 of 3 diets: Purina Chow, hydrogenated soybean fat, and milk fat diets. The fats were added at the level of 36% total calories in the case of the hydrogenated soybean and milk fat diets. Adrenal homogenates prepared from tissues of each group of animals at the end of the dietary periods were used to measure the relative abilities to synthesize corticosteroids from endogenous substrates. Endogenous free cholesterol levels were found adequate to sustain the level of corticosteroids obtained. No concomitant cholesteryl ester hydrolysis was observed under the experimental conditions used. The adrenal synthetic ability for the three dietary groups was in the order milk fat > Purina Chow > hydrogenated milk fat. This order appeared not to be a reflection of the essential fatty acid status of the animals in the three dietary groups. The possible basis for this trend, and the implications of the findings for carbohydrate, protein, and lipid metabolism in the animal are indicated.
Lipid products formed during desaturation of [1‐14C] stearyl CoA by hen liver microsomes
Authors: Holloway Caroline T. , Holloway P. W.
Published: November 2006

A number of lipid products are formed during the desaturation of stearyl CoA by hen liver microsomes. This article presents an analysis of the products formed when [1‐14C] stearyl CoA is incubated with hen liver microsomes for various time periods. [1‐14C] Oleyl CoA was the first radioactive unsaturated product formed. Synthesis of phospholipids containing [1‐14C] oleic acid occurs only after the desaturase activity has begun to decline. The specific radioactivity of [1‐14C] oleyl CoA was similar to the specific radioactivity of [1‐14C] stearyl CoA at all time periods tested. The specific radioactivities of [1‐14C] oleic acid and phospholipids containing [1‐14C] oleic acid were much lower than that of the [1‐14C] stearyl CoA.