Studies on the hypohalogenation of long chain α,β-unsaturated acids

As a result of hypohalogenation, a series oferythro 2(3)-halo-3(2)-hydroxy derivatives of C₁₆, C₁₈ and C₂₂ α, β-unsaturated acids have been prepared. The structures of the individual isomers were established by chemical and spectral methods. The major products were shown to be 2-halo-3-hydroxy alkanoic acids. Unlike internal halohydrins, the isomeric mixture of these derivatives of long chain α, β-unsaturated acids was successfully resolved by column chromatography.     

Fatty acid hydroxylase system in the Japanese harvest mouse,Micromys minutus

Liver microsomes of the Japanese harvest mouse (Micromys minutus), which is the smallest known mammal among rodents, catalyze the hydroxylation of various fatty acids (C₈ to C₁₈) to the corresponding ω-hydroxy and (ω-1)-hydroxy derivatives. Although laurate is most effectively hydroxylated among saturated fatty acids by liver microsomes of other species, harvest mouse liver microsomes most effectively catalyze the hydroxylation of decanoate. From inhibitor and cofactor studies, and from the substrate specificity for hydroxylation, it was concluded that ω- and (ω-1)-hydroxylation of fatty acids are catalyzed by different cytochrome P-450 species in the liver microsomes of the harvest mouse.     

Non-methylene Interrupted and Hydroxy Fatty Acids in Polar Lipids of the Alga Grateloupia turuturu Over the Four Seasons

Phospholipids (PL) and glycolipids (GL) FA in the edible Rhodophyta Grateloupia turuturu, from Brittany, France, were investigated over four seasons. The major lipid class was GL in all seasons (around 45 %). More than 80 FA occurred in polar lipids, with chains from C₁₂ to C₂₆, identified as methyl esters and N-acyl pyrrolidides by gas chromatography–mass spectrometry (GC–MS). PUFA occurred at up to 47.1 % (summer) in PL, and up to 43.6 % (summer) in GL. The major PUFA were 20:5n-3 (12.2 % in PL and 29.0 % in GL) and 20:4n-6 (25.6 % in PL and 10.4 % in GL). The unusual 18:3n-7 acid was identified in PL up to 2.2 %. Several minor unsaturated FA were identified in PL and are previously unreported in seaweeds, namely 14-tricosenoic, 15-tetracosenoic, 5,11-octadecadienoic and 5,9-nonadecadienoic. Also unprecedented in seaweeds, ten 2-hydroxy and three 3-hydroxy FA occurred mainly in PL, 13.9 % in spring with the 3-hydroxyhexadecanoic acid as the major one (8.1 % winter). Three n-9 monounsaturated 2-hydroxy FA occurred in PL. The 2-hydroxy-15-tetracosenoic acid was characterized as the dimethyl disulfide adduct of its methyl ester. The 2-hydroxy-16-pentacosenoic and 2-hydroxy-17-hexacosenoic acids were identified by comparison of mass spectra and GC mobilities with those of the 2-hydroxy-15-tetracosenoic acid, and of other homogeneous FA series. These rare n-9 monounsaturated 2-hydroxy FA are unprecedented in seaweeds.     

Occurrence of 2- and 3-hydroxy fatty acids in high concentrations in the extractable and bound lipids ofFlavobacterium meningosepticum andFlavobacterium IIb

The major hydroxy fatty acids of cellular lipids inFlavobacterium meningosepticum andFlavobacterium sp. King’s group IIb were identified as 2-hydroxy 13-methyltetradecanoic, 3-hydroxy 13-methyltetradecanoic, 3-hydroxy palmitic, and 3-hydroxy 15-methylhexadecanoic acids using gas chromatography-mass spectrometry and GC-mass fragmentography. The concentration of these hydroxy fatty acids comprised up to 30–40% of the total extractable and 20–30% of the bound lipid fatty acids, respectively. From the stability for mild alkaline hydrolysis, 2-hydroxy fatty acids seemed to be attached with ester linkage, and 3-hydroxy fatty acids with amide linkage.     

Variation,Modification and Engineering of Lipid A in Endotoxin of Gram-Negative Bacteria

Lipid A of Gram-negative bacteria is known to represent a central role for the immunological activity of endotoxin. Chemical structure and biosynthetic pathways as well as specific receptors on phagocytic cells had been clarified by the beginning of the 21st century. Although the lipid A of enterobacteria including Escherichia coli share a common structure, other Gram-negative bacteria belonging to various classes of the phylum Proteobacteria and other taxonomical groups show wide variety of lipid A structure with relatively decreased endotoxic activity compared to that of E. coli. The structural diversity is produced from the difference of chain length of 3-hydroxy fatty acids and non-hydroxy fatty acids linked to their hydroxyl groups. In some bacteria, glucosamine in the backbone is substituted by another amino sugar, or phosphate groups bound to the backbone are modified. The variation of structure is also introduced by the enzymes that can modify electrostatic charges or acylation profiles of lipid A during or after its synthesis. Furthermore, lipid A structure can be artificially modified or engineered by the disruption and introduction of biosynthetic genes especially those of acyltransferases. These technologies may produce novel vaccine adjuvants or antagonistic drugs derived from endotoxin in the future.     

The Di- and triesters of the lipids of steer and human meibomian glands

Three groups of diesters have been isolated and identified in the lipids of steer meibomian glands. The first group, designated as α Type I, with the abbreviated formula FA-αOHFA-FA1c, consisted of α-hydroxy fatty acids esterified to fatty acids and fatty alcohols in the approximate molar ratio 1∶1∶1. The second group, designated as ω Type I-St, with the abbreviated formula FA-ωOHF A-St, consisted of ω-hydroxy fatty acids esterified to fatty acids and sterols in the approximate molar ratio 1∶1∶1. The third group, designated as α,ω Type II, with the abbreviated formula FA-α,ωdiol-FA, consisted of α,ω-diols esterified to 2 moles of fatty acids. The sum of the different diesters comprised about 9% of total steer meibomian lipids. Capillary GLC of the fatty acids of αType I diesters showed the fatty acids to be a family with a two-cluster profile, one at C₁₂ to C₂₀ and the other at C₂₁ to C₃₁, with anteiso chains predominating. Fatty acids from ωType I-St and α,ωType II diesters gave mainly a one-cluster profile in the short long chain, C₂₃ to C₃₀, with anteiso chains predominating, while the α-hydroxy fatty acids were short chain C₁₃ to C₁₈ acids with C₁₆ predominating. The sterols in diesters ωType I-St were cholesterol (∼60%), Δ7 cholestenol (∼35%) and an unidentified compound (∼5%) with a GLC retention time slightly longer than Δ7 cholestenol on SE-30 phase. The ω-hydroxy fatty acids and α,ω-diols both were of exceedingly long chain lengths, C₂₉−C₃₈, and showed similar GLC profiles. Two types of triesters comprising approximately 1% of total steer meibomian lipids have been isolated but incompletely characterized. In terms of molar ratios, one group of triesters gave fatty acids:ω-hydroxy fatty acids:α-hydroxy fatty acids:sterols + fatty alcohols as approximately 1∶1∶1∶1. The other contained fatty acids, α-hydroxy fatty acids and α,ω-diols in what appears to be a complex mixture of several triesters. Diesters ωType I and α,ωType II also were found in human meibum. Hitherto these two diesters have not been found in any animal tissue.     

Ceramides from the spongeDysidea etheria

Ceramides have been isolated from the polar organic extracts of the spongeDysidea etheria. The ceramides proved to be amides of sphingosine with either normal, saturated fatty acids or saturated α-hydroxy fatty acids. Sphingosine was identified by isolation from the hydrolysis reaction mixture, acetylation and comparison of its physical and spectral properties with those reported for authentic sphingosine triacetate. The acids were identified by gas chromatography-mass spectrometry analysis of their respective methyl esters.     

Chromatographic separation of lactone precursors and tentative identification of the γ-lactones of 4-hydroxy octanoic and 4-hydroxy nonanoic acids in butterfat

A combination of silicic acid column and thin layer chromatography which separates γ- and δ-hydroxy acid containing glycerides from butterfat is described. This procedure facilitates the isolation of the γ- and δ-hydroxy acids (lactone precursors) while avoiding lactonization. The method indicated that the hydroxy acids are entirely esterified to the glyceride in fresh butterfat. Hydrolysis, using pancreatic lipase, showed that these polar acids are located on the α-positions of the glycerides. The γ-lactones of 4-hydroxy octanoic and 4-hydroxy nonanoic acids were tentatively identified by gas liquid chromatography. These occurred in quantities of 0.25–0.5 ppm and approximately 0.2 ppm respectively in the butterfat samples investigated. Authorized for publication on June 22, 1966, as Paper No. 3156 in the journal series of the Pennsylvania Agricultural Experiment Station.     

Synthesis of 6-hydroxy δ-lactones and 5,6-dihydroxy eicosanoic/docosanoic acids from meadowfoam fatty acids via a lipase-mediated self-epoxidation

Meadowfoam fatty acids were reacted with hydrogen peroxide in a lipase-catalyzed autocatalytic system, forming a mixture of 5,6-epoxyeicosanoic, 13,14-epoxydocosanoic, 5,6-epoxydocosanoic, and 5,6-13,14-diepoxydocosanoic acids in 98% yield. The 5,6-epoxy acids were cyclized to 6-hydroxy δ-eicosanoic/docosanoic lactones by sulfuric acid catalysis in high yield (99%). 5,6-Dihydroxy acids could be obtained from 6-hydroxy δ-lactones by a simple alkaline work-up procedure. Meadowfoam fatty acids were converted (77% yield) in a one-pot reaction to 6-hydroxy δ-lactones by in situ performic acid epoxidation and subsequent addition of sulfuric acid.     

Oxidation of C18 Hydroxy-Polyunsaturated Fatty Acids to Epoxide or Ketone by Catalase-Related Hemoproteins Activated with Iodosylbenzene

Small catalase-related hemoproteins with a facility to react with fatty acid hydroperoxides were examined for their potential mono-oxygenase activity when activated using iodosylbenzene. The proteins tested were a Fusarium graminearum 41 kD catalase hemoprotein (Fg-cat, gene FGSG_02217), a Pseudomonas fluorescens Pfl01 catalase (37.5 kD, accession number WP_011333788.1), and a Mycobacterium avium ssp. paratuberculosis 33 kD catalase (gene MAP-2744c). 13-Hydroxy-octadecenoic acids (which are normally unreactive) were selected as substrates because these enzymes react specifically with the corresponding 13S-hydroperoxides (Pakhomova et al. 18:2559–2568, 5; Teder et al. 1862:706–715, 14). In the presence of iodosylbenzene Fg-cat converted 13S-hydroxy-fatty acids to two products: the 15,16-double bond of 13S-hydroxy α-linolenic acid was oxidized stereospecifically to the 15S,16R-cis-epoxide or the 13-hydroxyl was oxidized to the 13-ketone. Products were identified by UV, HPLC, LC–MS, NMR and by comparison with authentic standards prepared for this study. The Pfl01-cat displayed similar activity. MAP-2744c oxidized 13S-hydroxy-linoleic acid to the 13-ketone, and epoxidized the double bonds to form the 9,10-epoxy-13-hydroxy, 11,12-epoxy-13-hydroxy, and 9,10-epoxy-13-keto derivatives; equivalent transformations occurred with 9S-hydroxy-linoleic acid as substrate. In parallel incubations in the presence of iodosylbenzene, human catalase displayed no activity towards 13S-hydroxy-linoleic acid, as expected from the highly restricted access to its active site. The results indicated that with suitable transformation to Compound I, monooxygenase activity can be demonstrated by these catalase-related hemoproteins with tyrosine as the proximal heme ligand.     

Effects of hydrocarbon structure on fatty acid,fatty alcohol,and β-hydroxy acid composition in the hydrocarbon-degrading bacterium <Emphasis Type="Italic">Marinobacter hydrocarbonoclasticus</Emphasis>

The lipids of the gram-negative bacterium Marinobacter hydrocarbonoclasticus grown in a synthetic seawater medium supplemented with various hydrocarbons as the sole carbon source were isolated, purified, and their structures determined. The hydrocarbons were normal, iso, anteiso, and mid-chain branched alkanes, phenylalkanes, cyclohexylalkanes, and a terminal olefin. According to the sequential procedure used for lipid extraction, three pools were isolated: unbound lipids extracted with organic solvents (corresponding to metabolic lipids and to the main part of membrane lipids), OH⁻ labile lipids [mainly ester-bound in the lipopolysaccharides (LPS)], and H⁺ labile lipids (mainly amide-bound in the LPS). Each pool contained FA, fatty alcohols, and β-hydroxy acids. The proportions of these lipids in the unbound lipid pools were 84–98%, 1.1–11.6%, and 0.1–3.6% (w/w), respectively. The chemical structures of the lipids were strongly correlated with those of the hydrocarbons fed; analytical data suggested a metabolism essentially through oxidation into primary alcohol, then into FA and degradation via the β-oxidation pathway. Subterminal oxidation of the hydrocarbon chains, α-oxidation of FA or double-bond oxidation in the case of the terminal olefin, were minor, although sometimes substantial, routes of hydrocarbon degradation. Cyclohexyldodecanedid not support growth, likely because of the toxicity of cyclohexylacetic acid formed in the oxidation of the alkyl side chain. In the OH⁻ and H⁺ labile lipid pools, β-hydroxy acids, the lipophilic moiety of LPS, generally dominated (28–72% and 64–98%, w/w, respectively). The most remarkable feature of these cultures on hydrocarbons was the incorporation in LPS of β-hydroxy acids with C_odd, ω-unsaturated, iso, or anteiso alkyl chains in addition to the specific β-hydroxy acid of M. hydrocarbonoclasticus, 3-OH-n-12∶0. These β-hydroxy acids were tolerated insofar as their geometry and steric hindrance were close to those of the 3-OH-n-12∶0 acid.     

Preparation and applications of a polymer supported peroxotungstate complex as a novel polymeric oxidizing agent

A polymer supported anionic peroxotungstate compound [Amb]₂[W₂O₃(O₂)₄] is prepared and characterized by conventional methods. Its use as a stoichiometric oxidizing agent for a variety of organic compounds is described. With this reagent alcohols are converted to the corresponding carbonyl compounds. Decarboxylation of α-hydroxy acids proceeds quantitatively. Also thiols are converted to disulfides, hydroquinones to quinones, benzylamines to carbonyl compounds, tertiary amines to the N-oxides, phosphines to phosphine oxides, and sulfides to sulfones. Deprotection of oximes and oxidative deprotection of silyl ethers proceed easily.     

Stereospecific hydration of unsaturated fatty acids by bacteria

Three new 10-hydroxy fatty acids, all optically active, have been prepared by the anaerobic microbiological hydration of acis-9 double bond. Substrates that formed these new hydroxy fatty acids are linoleic, linolenic, and ricinoleic acids. The hydroxyl group has the D configuration and the methyl esters are levorotatory. Infrared, mass spectral, specific rotation and ultraviolet data on these compounds were determined. There was no migration of the unreated double bonds at C₁₂ and C₁₅ in linoleic or linolenic acids. The presence of a double bond in the 10-hydroxy fatty acids significantly increased the optical rotation of the methyl esters. The hydratase enzyme showed unusual specificity among Δ⁹ unsaturated acids. While it hydrates methylene interrupted and hydroxy unsaturated acids, it failed to hydrate either 9-decenoic, 12,13-epoxy- or 12-keto-cis-9-octadecenoic acids or sterculic acid. Presented at the AOCS Meeting, San Francisco, April 1969. No. Marketing and Nutrition Res. Div., ARS, USDA.     

Fatty acid amides and anilides,syntheses and antimicrobial properties

A series of fatty acid amides anilides was prepared and a number of compounds in the series were found to be highly active against gram positive bacteria but ineffective against gram negative organisms. The N,N-dimethyl- and N,N-diethylamides of C₁₂-C₁₄ fatty acids had minimal inhibitory concentration (MIC) values of 100 ppm or less. Substituted anilides of C₆-C₁₁ fatty acids were active when the following groups were attached to the aromatic ring: 3,4-dichloro, 3-nitro, 4-nitro, 5-chloro-2-hydroxy, 4-chloro-3-nitro, and 2-hydroxy-5-nitro. Some of these compounds had a MIC value of 0.1 ppm. Significantly, the presence of soap did not reduce the activity of these bacteriostats, whereas polysorbate 80 at high concentrations deactivated the compounds. Presented at the AOCS Meeting in St. Louis, May 1978. Agricultural Research, Science and Education Administration, U.S. Department of Agriculture.     

2-Hydroxyhexadecanoic and 8,9,13-trihydroxydocosanoic acid accumulation by yeasts treated with fumonisin B1

Fumonisin B₁ is a sphingolipid-like compound that enhances the accumulation of yeast sphingolipids and 2-hydroxy fatty acids. These lipids occur both as freely extractable and cell bound components in yeast fermentations. Both free and bound 2-hydroxy fatty acids produced byPichia sydowiorum NRRL Y-7130 were increased when fumonisin B₁ (50 mg/L) was added to the usual growth medium containing yeast extract/malt extract/peptone/glucose. Fumonisin-treated cultures contained 38 mg/L more 2-hydroxyhexadecanoic and 15 mg/L more 2-hydroxyoctadecanoic acids than did untreated cultures. By contrast, fumonisin inhibited the accumulation of free 8,9,13-trihydroxydocosanoic acid inRhodotorula sp. YB-2501 cultures, leading to 240 mg/L lower trihydroxy acid production than by untreated cultures.     

Production of hydroxy fatty acids from unsaturated fatty acids byFlavobacterium sp. DS5 hydratase,a C-10 positional- andcis unsaturation-specific enzyme

A new microbial isolate,Flavobacterium sp. DS5, converted oleic and linoleic acids to their corresponding 10-keto-and 10-hydroxy fatty acids. The hydration enzyme seems to be specific to the C-10 position. Conversion products from α- and γ-linolenic acids were identified by gas chromatography/mass spectrometry, Fourier transform infrared, and nuclear magnetic resonance as 10-hydroxy-12(Z),15(Z)-octadecadienoic and 10-hydroxy-6(Z),12(Z)-octadecadienoic acids, respectively. Products from other 9(Z)-unsaturated fatty acids also were identified as their corresponding 10-hydroxy- and 10-keto-fatty acids.Trans unsaturated fatty acid was not converted. From these results, it is concluded that strain DS5 hydratase is indeed a C-10 positional-specific andcis-specific enzyme. DS5 hydratase prefers an 18-carbon monounsaturated fatty acid. Among the C₁₈ unsaturated fatty acids, an additional double bond at either side of the 9,10-position lowers the enzyme hydration activity. Because hydratases from other microbes also convert 9(Z)-unsaturated fatty acids to 10-hydroxy fatty acids, the C-10 positional specificity of microbial hydratases may be universal.     

Synthesis and characterization of polyhedral oligomeric silsesquioxane-based waterborne polyurethane nanocomposites

A series of aqueous polyurethane nanocomposites were prepared using various amounts (0.3-4.6 wt%) of a diol functionalized polyhedral oligomeric silsesquioxane (POSS) by the prepolymer mixing method. N,N-bis(2-hydroxy ethyl-2-amino ethane sulfonic acid sodium salt (BES sodium salt) was used as the anionic internal emulsifier and ionic center. The molecular structure of the samples was characterized by ATR-FTIR spectroscopy. We investigated the effect of the POSS contents on the properties of the specimens by particle size and viscosity measurements, X-ray diffractometry, mechanical behavior assessment, dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis and morphological studies. The results showed that with increasing the POSS contents, particle size, viscosity, tensile strength, modulus, T _g , and thermal stability of the synthesized samples were improved. Also, SEM and TEM images indicated that a homogeneous morphology was obtained in the 1.2 wt% POSS-based sample. AFM results showed that the surface roughness increased as the POSS amounts increased.     

A convenient preparaton ofγ-lactones and dialkyltetrahydrofurans from the reaction of fatty acids with epoxides using lithium naphthalenide

Fatty acids reacted with epoxides using lithium naphthalenide in the presence of diethylamine to give corresponding 4-hydroxy acids. These 4-hydroxy acids easily tended to cyclize into their correspondingγ-lactones by refluxing in benzene. Reduction of theseγ-lactones with lithium aluminum hydride followed by intramolecular dehydration with potassium bisulfate afforded corresponding dialkyl tetrahydrofuran derivatives in high yields. For example, 4-methyl-2-(8-nonenyl)γ-butyrolactone (III) was obtained from 10-undecylenic acid and propylene oxide. 2-Methyl-4-(8-nonenyl) tetrahydrofuran (IV) was produced from (III). 2-Methyl-4-(8-nonenyl) and 2-ethyl-4-(8-nonenyl) tetrahydrofurans are woody smelling and may be used as perfumery materials.     

Studies of the reactions of anhydrosulphites of α-hydroxy acids,part IX. thermal polymerisation of anhydrosulphites of α-hydroxy α-methyl carboxylic acids

The anhydrosulphites of a series of unsymmetrically substituted α-hydroxy acids have been prepared and their susceptibility to polymerisation by thermal decomposition studied. The first order rate determining ring scission process, leading to the formation of a reactive α-lactone intermediate which then undergoes spontaneous polymerisation, is the predominant mechanism even with substituents up to C₈. As the length of the n-alkyl substituent is increased the rate of decomposition and thus polymerisation increases until a plateau value is reached at around C₃. Further increase in substituent length decreases the rate of decomposition, an effect which is attributed to steric hindrance of the leaving group by long (C₆—C₈) substituents.