Ring location in cyclopropane fatty acid esters by a mass spectrometric method

Isolation, Synthesis, and Biological Activity of Chlorinated Alkylresorcinols from Dictyostelium Cellular Slime Molds

Eight chlorinated alkylresorcinols, monochasiol A-H (1-8), were isolated from the fruiting bodies of Dictyostelium monochasioides. Compounds 1-8 were synthesized to confirm their structures and to obtain sufficient material for performing biological tests. Monochasiol A (1) selectively inhibited the concanavalin A-induced interleukin-2 production in Jurkat cells, a human T lymphocyte cell line. Monochasiols were biogenetically synthesized by the combination of biosynthetic enzymes relating to the principal polyketides, MPBD and DIF-1, produced by Dictyostelium discoideum.

A variety of glycolipids in green photosynthetic bacteria

The compositions of glycolipids in the following seven strains of green photosynthetic bacteria were investigated at the molecular level using LC-MS coupled with an evaporative light scattering detector: Chlorobium (Chl.) limicola strains Larsen (30 °C as the optimal cultivation temperature) and DSM245 (30 °C), Chlorobaculum (Cba.) tepidum strain ATCC49652 (45 °C), Cba. parvum strain NCIB8327 (30 °C), Cba. limnaeum strain 1549 (30 °C), Chl. phaeovibrioides DSM269 (30 °C), and Chloroflexus (Cfl.) aurantiacus strain J-10-fl (55 °C). Dependence of the molecular structures of glycolipids including the chain-length of their acyl groups upon bacterial cultivation temperatures was clearly observed. The organisms with their optimal temperatures of 30, 45, and 55 °C dominantly accumulated glycolipids possessing the acyl chains in the range of C(15)-C(16), C(16)-C(17), and C(18)-C(20), respectively. Cba. tepidum with an optimal temperature of 45 °C preferred the insertion of a methylene group to produce finally a C(17)-cyclopropane chain. Cfl. aurantiacus cultured optimally at 55 °C caused a drastic increase in the chain-length. Notably, the length of such acyl groups corresponded to that of the esterifying chain in the 17-propionate residues of self-aggregative bacteriochlorophylls-c/d/e, indicating stabilization of their supramolecular structures through hydrophobic interactions among those hydrocarbon chains. Based on the detailed compositions of glycolipids, a survival strategy of green photosynthetic bacteria grown in the wide range of temperatures is discussed.

Fatty Acids of Chthonomonas calidirosea, of a novel class Chthonomonadetes from a recently described phylum Armatimonadetes

A Gram-negative, aerobic, pink-pigmented, rod-shaped bacterium Chthonomonas calidirosea (strain T49(T)) with an optimal temperature for growth of 68 °C, isolated from soil samples from Hell's Gate in the Tikitere geothermal system (New Zealand), was the first cultivated bacterium of the novel phylum Armatimonadetes (formerly candidate division OP10). The lipid composition of C. calidirosea presents a number of unusual features both in the fatty acids and polar lipids. This contribution reports on the fatty acid profile of C. calidirosea. Transmethylation of bacterial biomass yielded fatty acid methyl esters and hydrocarbons, including squalene, partially hydrogenated squalenes, and diploptene. The only type of unsaturation found in C. calidirosea fatty acids was cis-Δ5, as revealed by GCMS of dimethyl disulfide (DMDS) adducts, and the lack of trans-unsaturation absorbance at 960-980 cm(-1) in the IR spectrum of fatty acids methyl esters. An unidentified component X with ECL 16.86 (BP1) and ECL 17.27 (BP20) was also observed, with molecular ion at m/z 282 ("17:1"). X did not form DMDS adducts, nor was affected by mild hydrogenation conditions, indicating the likely presence of a ring rather than unsaturation. The presence of a cyclopropane ring with cis-stereochemistry was confirmed by the (1)H-NMR spectrum. Hydrogenation of X in acetic acid resulted in formation of straight chain 17:0, 5-methyl- and 6-methyl-16:0 fatty acid methyl esters, thus confirming the structure of a novel 5,6-methylene hexadecanoic acid. The major fatty acids of a solid media-grown C. calidirosea were as follows (in weight % of total fatty acids): 16:0 (25.8), i17:0 (19.3), ai17:0 (13.5), 16:1∆5 (8.8), i17:1∆5 (6.8), 5,6-methylene 16:0 (5.2), i16:0 (4.4), 18:0 (3.6), 18:1∆5 (3.2).

Differences in fatty acid composition between vegetative cells and N(2)-fixing vesicles of Frankia sp. strain CpI1

When growing on N(2), actinomycetes from the genus Frankia form multicellular structures that contain nitrogenase. The structures are referred to as vesicles and are indistinguishable from vesicles formed when Frankia sp. are in root-nodule symbioses. Vesicles isolated from N(2)-grown cells of Frankia sp. strain CpI1 had a significantly higher amount and different composition of fatty acids than did vegetative cells recovered from NH(4) (+)-containing medium. Lipids from vesicles, whole cells grown on N(2), and whole cells grown on NH(4) (+) were fractionated by silicic acid chromatography into neutral lipids, glycolipids, and polar lipids. The fatty acids were transesterified by methanolysis and analyzed by gas chromatography and mass spectrometry. Vesicles had considerably higher amounts of fatty acids in the neutral and glycolipid fractions but lower amounts of polar lipid fatty acids than did vegetative cells. Polar lipids from vesicles had a higher proportion of mono-unsaturated and cyclopropane fatty acids and a lower proportion of isobranched fatty acids than did polar lipids from NH(4) (+)-grown or N(2)-grown cells. The neutral lipid and glycolipid fractions contained several long-chain compounds with molecular ions at m/z 408 and 410. The proportions of these compounds were significantly higher in the lipids from vesicles than from vegetative cells. These results suggest that lipids in vesicles might be involved in the protection of nitrogenase from O(2) and suggest a parallel with the glycolipids involved in protecting nitrogenase from O(2) in the cyanobacterial heterocysts.

Analyses of barley spike mutant waxes identify alkenes, cyclopropanes and internally branched alkanes with dominating isomers at carbon 9

About 15% of the epidermal wax on Hordeum vulgare cv. Bonus barley spikes is n-alkanes. Longer homologues are greatly reduced in the eceriferum mutants, cer-a(6), cer-e(8), cer-n(26), cer-n(53), cer-n(985), cer-x(60), cer-yc(135) and cer-yl(187). Simultaneously hydrocarbons accounting for only traces in the wild-type become prominent in the mutants, although their chain-length distributions remain unchanged. Accordingly several new hydrocarbon series were identified. The two major ones were C(23)-C(35)cis monoenoic alkenes (the major 9-ene isomer was part of a homologous series including 11, 13 and 15-enes), and the novel C(27)-C(31) cyclopropanes (the ring carbons of major isomers were 9,10 and 11,12 with lesser amounts of 13,14). Three minor series included 2- and 3-methylalkanes plus C(25)-C(33) internally branched alkanes (methyls on carbons 9, 11, 13, 15 or 17; shorter homologues dominated by the 9 isomer, longer homologues by 11, 13 or 15 isomers). Acyl chains destined for spike waxes are synthesized via acyl and polyketide elongase systems plus associated reductive and decarbonylative/decarboxylative enzyme systems. Both elongation systems are defective in synthesizing C(32) acyl chains in all nine mutants. The similarities in the position of the chemical groups (primarily on carbon 9, secondarily on carbon 11) of the alkenes, cyclopropanes and internally branched methyl alkanes imply an origin from a common, hitherto unrecognized associated pathway in barley, designated the enoic pathway. The elongation system leading to the enoic derived hydrocarbons differs from the known elongation systems by inclusion of a mechanism for introducing a double bond.

Gracilarioside and gracilamides from the red alga Gracilaria asiatica

One gracilarioside and two gracilamides with unusual cyclopropane-containing alkyl chains were isolated from the red alga Gracilaria asiatica. Their structures were determined by spectroscopic methods and microscale chemical degradation. To our knowledge, no ceramides with a cyclopropane ring have been reported from marine organisms. These three compounds were mildly cytotoxic to the human A375-S2 melanoma cell line.

Review: derivatization in mass spectrometry--5. Specific derivatization of monofunctional compounds

The present paper is complementary to the foregoing reviews and describes some additional methods of the derivatization of particular functional groups mainly to enhance the structural information content of electron ionization and chemical ionization mass spectra. Derivatization approaches for the modification of unsaturated compounds, alcoholic, carboxylic, carbonyl, amine and other functional groups, are discussed. Derivatization for separation and quantitative determination of chiral enantiomeric compounds is also considered. Preliminary chemical and physicalchemical degradation for structure elucidation of high molecular weight compounds (biopolymers, synthetic polymers) is mentioned. Chemical aspects of derivatizations and characteristic mass spectral features of derivatives are described briefly. Some particular applications of chemical modification, in conjunction with mass spectral measurements for the analysis of various important bioorganic compounds and compounds in biological fluids, air, environmental etc., are considered.

Fatty acid composition of the cellular slime mold Polysphondylium pallidum

The cellular slime mold Polysphondylium pallidum was grown upon Escherichia coli B/r, and the fatty acid compositions of total lipids obtained from vegetative amebae and aggregation-competent cells were compared. Fatty acids isolated from vegetative cells included C-17 and C-19 cyclopropane fatty acids and also straight-chain, saturated fatty acids. The cyclopropane fatty acids were derived from the ingested bacteria. Development of amebae to aggregation-competent cells was accompanied by a substantial decrease in saturated cyclopropane fatty acids and a concomitant increase in unsaturated fatty acids and unsaturated cyclopropane fatty acids, mostly as 18:3 (5,9,12). We report here the fatty acid composition and identify the occurrence of delta 5 desaturation of cyclopropane fatty acids, namely, 9,10-methylene 5-hexadecenoic acid and 11,12-methylene 5-octadecenoic acid. These fatty acids have not been reported previously in the related species Dictyostelium discoideum, which also feeds on E. coli B/r and has delta 5-desaturation activity.

Differentiation of Brucella ovis from Brucella abortus by gas-liquid chromatographic analysis of cellular fatty acids

The cellular fatty acid composition of Brucella ovis and Brucella abortus strains was determined by gas-liquid chromatography. Both species were characterized by the presence of fatty acids 16:0, 17:0, 17:0 cyclopropane, 18:0, 18:1, and 19:0 cyclopropane; B. ovis also contained some 15:0. There were differences in the relative proportions of the fatty acids present, and it was possible to differentiate B. ovis from B. abortus on the basis of the absence of 15:0, lower concentrations of 17:0 and 18:1, and higher concentrations of 19:0 cyclopropane in B. abortus. The data indicate that analysis of cellular fatty acid composition by gas-liquid chromatography can be used for the identification of B. ovis and its differentiation from B. abortus.

Further studies of the saturated methyl branched fatty acids of vernix caseosa lipid

By the method of capillary gas chromatography-mass spectrometry, we have identified 35 monomethyl and 46 dimethyl branched acids in the saturated acids of vernix caseosa lipid with chain lengths ranging from C11 to C18. Many other mono-, di-, and trimethyl branched acids have been partially identified. All methyl branches were found to be on the even numbered C-atoms except for some terminal iso methyl groups. Three types of dimethyl branched acids were found: those with a terminal iso structure, those with a terminal anteiso structure, and those with neither iso nor anteiso structures. The 4-methyl branch predominated for all types of branched acids. Equivalent chain length data for di- and trimethyl branched acids were determined on a Pentasil (nonpopolar) wall coated capillary column and checked by calculation from monomethyl branched acid data. Mass spectral identification was performed with and without the aid of a data system. A possible mode of formation of these acids is discussed.

Antimicrobial effect of simple lipids with different branches at the methyl end group

Various fatty acids of branched nature possess fungistatic and bacteriostatic properties. Some of these, particularly those of iso-configuration, strongly enhance the effect of conventional antimicrobial agents that act inside the cell membrane. A relation between this biological effect and the collapse properties of the corresponding monomolecular surface film on water has been observed. In this work, a series of fatty acids with a slightly smaller end group than iso-propyl, the omega-cyclopropane fatty acids, as well as one possessing a somewhat larger end group, the neo-branched fatty acids, have been examined. The omega-cyclopropane fatty acids were found to be more fungistatic than the iso-acids studied earlier. Furthermore, both cyclopropane and neo-fatty acids of short chain lengths exhibited synergistic effects in combination with tetramethylthiuramdisulfide.

Fatty acid composition of thermophilic, mesophilic, and psychrophilic clostridia

The fatty acid composition of two thermophilic anaerobes was determined, and the results were compared with those from a mesophilic and a psychrophilic anaerobe. Notable differences were that the thermophiles contained a higher content of saturated straight- and branched-chain fatty acids, and, of the latter, iso C(15) was the predominant type. The mesophile and psychrophile were characterized by having a higher percentage of unsaturated fatty acids. An unidentified fatty acid, present in all of the organisms, was purified from the psychrophile. By physical and chemical analysis the structure of the unknown acid was resolved and found to be the unsaturated cyclopropane fatty acid, 12,13-methylene-9-tetradecenoic acid.

Biosynthesis of cyclopropyl long-chain fatty acids from cyclopropanecarboxylic acid by mammalian tissues in vitro

1. Radioactivity from cyclopropane[(14)C]carboxylic acid is incorporated into fatty acids in vitro by rat and guinea-pig adipose tissue, by rat liver slices and by the supernatant fraction of rat liver homogenate. 2. The labelled acids are different from endogenous straight-chain fatty acids, and evidence is produced that they consist of a cyclopropyl ring in the omega-position, the remainder of the chain being built up from C(2) units (not derived from cyclopropanecarboxylic acid) in the normal way via the malonate pathway. 3. It is suggested that these unnatural acids have some metabolic effect related to the hypoglycaemic action of cyclopropanecarboxylic acid.