Quality of yellow and dark seeds inBrassica campestris canola varieties Candle and Tobin

Yellow-coated seeds from theBrassica campestris cultivars Tobin and Candle were heavier and contained more oil and protein than the dark-coated seeds from the same sample. In addition, the yellow-coated seeds had lower levels of erucic acid, glucosinolates, chlorophyll and crude fiber. These differences were detected in both pedigreed and commercial (producer) samples, but to a larger extent in commercial samples. Reasons for the greater quality differences between yellow- and dark-coated seed could be admixtures of cultivars other than the declared ones of Tobin or Candle or changes in the seed itself as it went from the breeder’s stage to the producer stage.     

Rapid separation of neutral lipids,free fatty acids and polar lipids using prepacked silica sep-Pak columns

A method is described for the separation of neutral lipid, free fatty acid and polar lipid classes using small (600 mg), prepacked silica Sep-Pak columns. Combinations of hexane and methyltertiarybutylether were used to progressively elute cholesteryl ester first then triglyceride from the column. After column acidification, fatty acids were eluted followed by cholesterol. Recoveries of these lipids were 96% or greater. Polar lipids were eluted from the column using combinations of methyltertiarybutylether, methanol and ammonium acetate. Phospholipid classes could not be separated completely from each other. Phosphatidylethanolamine and phosphatidylinositol eluted together, whereas the more polar phosphatidylcholine, sphingomyelin and lysophosphatidylcholine were eluted as a second fraction. Recoveries of each phospholipid was greater than 98%.     

Determination of free and bound gossypol in swine tissues

Methods have been developed for the determination of free and bound gossypol in the tissues of swine ingesting diets containing free gossypol. Data presented show satisfactory reproducibility and accuracy of the methods. Published with the approval of the Director of Research of the N.C. Agricultural Exper. Sta. as Paper No. 1836 of the Journal Series.     

Mechanisms of free radical oxidation of unsaturated lipids

The primary producs formed from the autoxidation of lipids can be understood based upon a mechanism that involves five different reaction types. These reactions are: reaction of a carbon radical and molecular oxygen, atom transfer of a hydrogen from substrate to the chain carrying peroxyl, fragmentation of the chain carrying peroxyl to give oxygen and a carbon radical, rearrangement of the peroxyl, and cyclization of the peroxyl. The mechanisms of these primary reaction steps has been the focus of extensive research over the past fifty years, and the current level of understanding of these transformations is the subject of this review.     

Lipid metabolism of the yellow clam,Mesodesma mactroides: I. Composition of the lipids

The lipid composition of the yellow clam,Mesodesma mactroides, that lives in the northern beaches of the Buenos Aires province of Argentina was studied. The main nonpolar lipids are triglycerides and alkoxyglycerides. Phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidyl serine are the main phospholipids. The predominant fatty acids are 16∶0, 16∶1ω7, 18∶0, 18∶1ω9, 20∶5ω3, and 22∶6ω3. The are mainly provided by the clam's food and stored in the hepatopancreas. The content of polyunsaturated acids increases in summer together with an increase in nonpolar lipids and is correlative with an increase in phytoplankton in the sea water. Sexual maturity modifies the lipid composition of gametes.     

Fatty acids of canola Brassica campestris var candle seed and oils at various stages of refining

Fatty acids of oil of a current variety of canolaBrassica campestris var Candle, at 3 stages of commercial production and refining, were compared with authentic seed oils, and with the oil ofB. napus var Tower. The proportion ofcis- 9, cis- 12, trans- 15 andtrans- 9, cis-12, cis-lS-octadecatrienoates relative to the all-cis isomer was lower than that previously observed in processed oils. The minor C₁₄, C₁₅, C₁₇ fatty acids previously documented for Tower were also found in the same proportions in the Candle oil. The proportion of 22:1ω7 isomer (1.1% of a total 1.2% 22:1) was intermediate to that of a high erucic variety (0.9% out of 23% 22:1) and the very low 22:1 Tower (2.3% out of 0.1% 22:1). Thus the proportion of ω7 isomers is governed by total 22:1 present.     

Charge-reversal lipids, peptide-based lipids, and nucleoside-based lipids for gene delivery

Twenty years after gene therapy was introduced in the clinic, advances in the technique continue to garner headlines as successes pique the interest of clinicians, researchers, and the public. Gene therapy's appeal stems from its potential to revolutionize modern medical therapeutics by offering solutions to myriad diseases through treatments tailored to a specific individual's genetic code. Both viral and non-viral vectors have been used in the clinic, but the low transfection efficiencies when non-viral vectors are used have lead to an increased focus on engineering new gene delivery vectors. To address the challenges facing non-viral or synthetic vectors, specifically lipid-based carriers, we have focused on three main themes throughout our research: (1) The release of the nucleic acid from the carrier will increase gene transfection. (2) The use of biologically inspired designs, such as DNA binding proteins, to create lipids with peptide-based headgroups will improve delivery. (3) Mimicking the natural binding patterns observed within DNA, by using lipids having a nucleoside headgroup, will produce unique supramolecular assembles with high transfection efficiencies. The results presented in this Account demonstrate that engineering the chemical components of the lipid vectors to enhance nucleic acid binding and release kinetics can improve the cellular uptake and transfection efficacy of nucleic acids. Specifically, our research has shown that the incorporation of a charge-reversal moiety to initiate a shift of the lipid from positive to negative net charge improves transfection. In addition, by varying the composition of the spacer (rigid, flexible, short, long, or aromatic) between the cationic headgroup and the hydrophobic chains, we can tailor lipids to interact with different nucleic acids (DNA, RNA, siRNA) and accordingly affect delivery, uptake outcomes, and transfection efficiency. The introduction of a peptide headgroup into the lipid provides a mechanism to affect the binding of the lipid to the nucleic acid, to influence the supramolecular lipoplex structure, and to enhance gene transfection activity. Lastly, we discuss the in vitro successes that we have had when using lipids possessing a nucleoside headgroup to create unique self-assembled structures and to deliver DNA to cells. In this Account, we state our hypotheses and design elements as well as describe the techniques that we have used in our research to provide readers with the tools to characterize and engineer new vectors.     

Interference of polar lipids with the alkalimetric determination of free fatty acid in fish lipids

An examination of the suitability of an alkalimetric method for the determination of free fatty acid (FFA) contents in fats, oils, and lipid extracts was conducted by comparing AOCS method Ca 5a-40 with a method based on a Chromarod-latroscan thin-layer chromatography-flame-ionization detector (TLC-FID) system. The FFA contents determined by the alkalimetric method were consistently higher than the genuine FFA contents obtained by the latroscan TLC-FID method. Phospholipids were found to be the major components that contributed to the alkali-titratable, nongenuine FFA in the total FFA determined alkalimetrically. Contributions from other polar lipid components were smaller, but they dominated as the proportion of phospholipids fell. The other alkali-titratable polar components may include oxidized lipids and their by-products bound to protein fragments. The accurate determination of FFA contents by alkalimetric methods may only be applicable to those commercially refined fats and oils that contain negligible amounts of phospholipids. Corrections for the alkalimetrically determined FFA contents should be made for those fats and oils with relatively high phospholipid contents by correlating the nongenuine FFA contents and the phospholipid contents.     

Gas chromatographic analysis of free and bound malonaldehyde in rat liver homogenates

A gas chromatographic method for the measurement of free and bound malonaldehyde (MA) in rat liver homogenate was developed to investigate biological damage caused by lipid peroxidation. Free MA was derivatized by reaction withN-methylhydrazine (NMH) to form 1-methylpyrazole (1-MP), which was subsequently analyzed by capillary gas chromatography (GC). Bound forms of MA were determined by first hydrolyzing samples in acetic acid, then measuring the free MA as 1-MP. Bound MA in rat liver was released within 15 min by acid hydrolysis. A slight increase in bound MA levels in rat liver was observed 1 hr after CCl₄ treatment, with bound MA then returning to control levels. Free MA levels and thiobarbituric acid assay (TBA) values did not show appreciable changes over a 24-hr period after CCl₄ administration. However, the TBA values were approximately ten times the MA values in most samples.     

Brassica campestris var. Span: I. Fractionation of Rapeseed oil by molecular distillation and adsorption chromatography

Procedures for the large scale isolation of pure triglycerides and fractions rich in nontriglyceride components from Span rapeseed oil are described. Fractionation ofBrassica campestris var. Span rapeseed oil by molecular distillation yielded 4 triglyceride fractions, all of which contained traces of sterol esters. An additional triglyceride fraction rich in free and esterified sterols and other volatile components was obtained from the oil. Separation by adsorption chromatography of Span rapeseed oil yielded three fractions: A) a pure triglyceride fraction; B) a triglyceride fraction rich in sterol esters; and C) another fraction containing free sterols and other polar components. Contribution no. 559 Animal Research Institute.     

Enzymatic modification of lipids for trans‐free margarine

Several studies have shown that high intake of trans fat is associated with increased risk of chronic diseases especially cardiovascular disease. The levels of trans fat in the American diet is of concern. Structured lipid is a lipid that has been modified from its native form either by biocatalysts or chemical catalysts. These modifications result in change in the triacylglycerol molecular species which further alters the physicochemical properties such as melting properties, solid fat content, and oxidative stability of lipids. The process allows the production of a wide range of functional and nutritional lipids that may meet consumer needs. Enzymatically synthesized structured lipids can be used as a substitute for conventional lipids in trans‐free margarine formulations. This article gives an overview of trans fatty acids and enzymatic modification of lipids for producing trans‐free margarine.     

Metabolomic profiling can differentiate between bactericidal effects of free and polymer bound halogen

The effects of two halogenated compounds (sodium hypochlorite and N‐halamine polymers) on the Escherichia coli metabolome were investigated. Changes in the intracellular metabolite pools of bacterial cells treated with different formulations of these compounds were analysed using FTIR (Fourier Transform Infra Red) spectroscopy and LC‐MS (Liquid Chromatography‐Mass Spectroscopy). Principal component analysis was used to generate metabolic profiles of the intracellular metabolites to investigate the effect of sublethal concentrations on the metabolome of treated cells. The effect of treatment with sodium hypochlorite was quantitatively dependent on the exposure time. The resulting metabolic profiles supported our previous hypothesis that the mode of action of some halogenated compounds, such as N‐halamine polymers, can be initiated by release of halogen ions into the aqueous environment, in addition to direct contact between the solid polymer material and the bacterial cells. Moreover, the metabolic profiles were able to differentiate between the effect of free and polymer‐bound halogen. Our metabolomic approach was used for hypothesis generation to distinguish apparently different bactericidal effects of free and polymer‐bound halogen. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Measurement of free and bound malondialdehyde in vitamin E-deficient and-supplemented rat liver tissues

The quantity of free malondialdehyde (MDA) in liver tissues of rats fed vitamin E-deficient or-supplemented diets for 43 wk was measured by a newly developed high performance liquid chromatographic (HPLC) method. Bound MDA was quantified by the same HPLC method after alkaline hydrolysis of tissue homogenates. Tissues from vitamin E-deficient animals showed levels of free MDA about 15 times higher but levels of bound MDA less than 2 times higher than the vitamin E-supplemented animals. Free MDA is the major form in vitamin E-deficient tissues, but bound MDA is predominant in vitamin E-supplemented tissues. Conventional thiobarbituric acid (TBA) test results revealed that the content of TBA-reactive substances expressed in MDA equivalents was much higher than the actual free MDA levels in all groups. Results indicate that free MDA level measured by HPLC is a more sensitive index than the TBA value for lipid peroxidation. Some other TBA-reactive substances seem to exist in liver tissue regardless of the dietary treatment. Published as paper no. 14,952 of the Scientific Journal Series of the Minnesota Agricultural Experiment Station on research conducted under Minnesota Agricultural Experiment Station Project No. MN 18-085, supported by Hatch funds.     

Characterizing the kinetics of free and bound water using a non-isothermal sorption technique

This article presents novel techniques for characterizing the kinetics of the free and bound water in a specimen by performing only one single sorption experiment. By monitoring the time variation of the residual water in a specimen that undergoes a controlled non-isothermal sorption over the range of temperatures of interest, the initial mass of the free and bound water in the specimen, the Arrhenius constants of diffusivity of the free water, and the Arrhenius constants of the rate of dissolution of the bound water can be extracted through a combination of time–temperature transformation and regression.     

Quantitative analysis of free and bound fatty aldehydes: Optimum conditions for p-nitrophenylhydrazone formation

A method is described for the analysis of free and bound fatty aldehydes in lipid extracts. By radiolabeling techniques it was shown that the method for measuring free fatty aldehydes when used in the presence of bound fatty aldehydes measures less than 1% of the bound aldehydes. Parameters of time, temperature and optimum acid concentration are reported. A comparison has been made between the present method and other published methods of measuring p-nitrophenylhydrazones with emphasis on recoveries and reactivities. The present method is suitable for measuring as little as 0.02 μmoles of fatty aldehyde. The method has been applied to the analysis of free and bound aldehydes present in various mouse tissues.     

Humans,lipids and evolution

The genetically ordered physiology of contemporary humans was selected over eons of evolutionary experience for a nutritional pattern affording much less fat, particularly less saturated fat. Current dietary recommendations do not accord exactly with those generated by an understanding of prior hominoid/hominid evolution. Similarly, widely advocated standards for serum cholesterol values fail to match those observed in recently studied hunter-gatherers, whose experience represents the closest living approximation of “natural” human lipid metabolism. The evolutionary paradigm suggests that fats should comprise 20–25% of total energy intake, that the ratio of polyunsaturated to saturated fat should exceed 1.0, and that total serum cholesterol levels should be below 150 mg/dL (∼4 mM/L). Based on a paper presented at the Symposium on Lipids in Cancer held at the AOCS Annual Meeting, Baltimore, MD, April 1990.