Occurrence of free ceramides in Bacteroides fragilis NCTC 9343.

The occurrence of free ceramides at high concentrations was demonstrated in the chloroform-methanol extractable lipids of Bacteroides fragilis NCTC 9343. The long-chain bases were isolated from the free ceramides and identified as branched and normal saturated dihydroxy bases with carbon chains consisting of 17, 18, and 19 atoms. The major fatty acid was 3-hydroxy 15-methylhexadecanoic acid. The major molecular species of the ceramides were identified by gas chromatography-mass spectrometry and gas chromatography of the cleaved products as LCB-d-iso17: 0-3-OH iso17: 0 FA, LCB-d-anteiso17: 0-3-OH iso17: 0 FA, LCB-d-iso18: 0-3-OH iso17: 0 FA, and LCB-d-anteiso19: 0-3-OH iso17: 0 FA.     

Cellular fatty acid composition from Sarcobium lyticum (Legionella lytica comb. nov.)--an intracellular bacterial pathogen of amoebae

Legionella lytica comb. nov. an intracellular bacterial pathogen of small free-living amoebae was subjected to cellular fatty acid (FA) analysis employing base and acid catalyzed cleavage, gas-liquid chromatography and mass spectrometry. Both unbranched and branched (iso and anteiso) FA of chains ranging from 14 to 30 carbon atoms occurred. The presence of two long-chain FA: 27-oxo-octacosanoic acid and heptacosane-1,27-dioic acid, characteristic for legionellae, was found. Nine amide-linked 3-hydroxy-FA were revealed. The main 3-hydroxy-fatty acids comprise: 3-OH-14:0, 3-OH-16:0, 3-OH-18:0, 3-OH-i18:0, 3-OH-15:OH, 3-OH-i16:0 amd 3-OH-i17:0. The profile of hydroxy FAs permits allocation of L. lytica to group 3 of legionellae which comprise blue-white fluorescent species.     

Comparison of fatty acid compositions of azooxanthellate Dendronephthya and zooxanthellate soft coral species

Ten zooxanthellae-free Dendronephthya species , twelve zooxanthellate soft coral species of the genera Sarcophyton, Lobophytum, Cladiella, Lytophyton, Cespitularia, and Clavularia, and the hermatypic coral Caulastrea tumida were examined for the first time to elucidate the fatty acid (FA) composition of total lipids. In Dendronephthya species, the main FAs were 20:4n-6, 24:5n-6, 16:0, 18:0, 7-Me-16:1n-10, and 24:6n-3 which amounted on the average to 26.0, 12.7, 12.1, 6.0, 4.8, and 4.0% of the total FA contents, respectively. For zooxanthellate soft corals, the main FAs were 16:0 (25.7%), 20:4n-6 (18.2%), 24:5n-6 (6.2%), and 18:4n-3 (5.6%), as well as 16:2n-7, which amounted up to 11.8% in Sarcophyton aff. crassum. Corals with zooxanthellae had low contents of 24:6n-3. The significant difference (p<0.01) between azooxanthellate and zooxanthellate soft corals was indicated only for 12 of 46 FAs determined. The principal components analysis confirmed that 7-Me-16:1n-10, 17:0, 18:4n-3, 18:1n-7, 20:4n-6, 22:5n-6, 24:5n-6, and 24:6n-3 are useful for chemotaxonomy of Dendronephthya. The azooxanthellate soft corals studied were distinguished by the absence of significant depth-dependent and species-specific variations of FA composition, low content of 16:2n-7, an increased proportion of bacterial FAs, predominance of n-6 FAs connected with active preying, and a high ability for biosynthesis of tetracosapolyenoic FAs.     

Changes in C12:0, C18:1, C18:2 and C20:2 fatty acid content in wheat treated with resistance inducers and infected by powdery mildew

This work presents a global investigation of total fatty acid (FA) content in wheat in relation to treatment with four inducers of resistance and to powdery mildew infection. Linolenic acid (C18:3), linoleic acid (C18:2) and palmitic acid (16:0) were the most abundant FAs in wheat leaves. We investigated the effect of the following inducers of resistance: Iodus40, heptanoyl salicylic acid (HSA), Milsana and trehalose on FA accumulation. Previous studies established that lipid metabolism is altered by these compounds, and we therefore aimed to characterise their impact at the FA level. During a time course experiment, content (quantitative analysis) and percentage (qualitative analysis) of FAs were compared in treated plants and in controls, as well as in plants inoculated with Blumeria graminis f. sp. tritici (i) and non-inoculated (ni) plants. No change in C18:3 content was observed. C18:1 in Iodus 40-treated (ni) plants showed a quantitative 1.2-fold increase. Lauric acid (C12:0) content quantitatively increased after Iodus 40 (2.8-fold), Milsana (4.8-fold) and trehalose (4.0-fold) treatment in (i) plants. However, eicosadienoic acid (C20:2) quantitatively decreased in (ni) plants after Iodus 40 (1.5-fold) and Milsana (2.3-fold) treatment. The amount of C18:2 increased (1.6-fold) after HSA treatment in (i) plants. All these variations in FA content were correlated with variations in the corresponding relative percentages. Our work provides the first evidence for alterations in C12:0, C18:1, C18:2 and C20:2 FA content caused by four resistance inducers. We also compared the amount and percentage of each FA in untreated (i) and (ni) plants. In (i) plants, eicosadienoic acid (C20:2) increased and C18:2 decreased slightly. The potential involvement of these FAs during induced resistance and infection is discussed.     

Brucella abortus 16S rRNA and lipid A reveal a phylogenetic relationship with members of the alpha-2 subdivision of the class Proteobacteria

On the basis of ribosomal 16S sequence comparison, Brucella abortus has been found to be a member of the alpha-2 subdivision of the class Proteobacteria (formerly named purple photosynthetic bacteria and their nonphototrophic relatives). Within the alpha-2 subgroup, brucellae are specifically related to rickettsiae, agrobacteria, and rhizobiae, organisms that also have the faculty or the obligation of living in close association to eucaryotic cells. The composition of Brucella lipid A suggests a close phylogenetical relationship with members of the alpha-2 group. The chemical analysis of the lipid A fraction revealed that Brucella species contain both glucosamine and diaminoglucose, thus suggesting the presence of a so-called mixed lipid A type. The serological analysis with polyclonal and monoclonal antibodies is in agreement with the existence of mixed lipid A type in B. abortus. The amide-linked fatty acid present as acyl-oxyacyl residues were 3-O-C(16:0)12:0, 3-O-C(16:0)13:0, 3-O-C(16:0)14:0, and 3-O-C(18:0)14:0. The only amide-linked unsubstituted fatty acid detected was 3-OH-C16:0. The ester-linked fatty acids are 3-OH-C16:0, 3-OH-C18:0, C16:0, C17:0, and C18:0. Significant amounts of the large-chain 27-OH-C28:0 were detected together with traces of 25-OH-C26:0 and 29-OH-C30:0. Comparison of the Brucella lipid composition with that of the other Proteobacteria also suggests a close phylogenetical relationship with members of the alpha-2 subdivision. The genealogical grouping of Brucella species with pericellular and intracellular plant and animal pathogens as well as with intracellular plant symbionts suggests a possible evolution of Brucella species from plant-arthropod-associated bacteria.     

Age‐associated changes in long‐chain fatty acid profile during healthy aging promote pro‐inflammatory monocyte polarization via PPARγ

Differences in lipid metabolism associate with age‐related disease development and lifespan. Inflammation is a common link between metabolic dysregulation and aging. Saturated fatty acids (FAs) initiate pro‐inflammatory signalling from many cells including monocytes; however, no existing studies have quantified age‐associated changes in individual FAs in relation to inflammatory phenotype. Therefore, we have determined the plasma concentrations of distinct FAs by gas chromatography in 26 healthy younger individuals (age < 30 years) and 21 healthy FA individuals (age > 50 years). Linear mixed models were used to explore the association between circulating FAs, age and cytokines. We showed that plasma saturated, poly‐ and mono‐unsaturated FAs increase with age. Circulating TNF‐α and IL‐6 concentrations increased with age, whereas IL‐10 and TGF‐β1 concentrations decreased. Oxidation of MitoSOX Red was higher in leucocytes from FA adults, and plasma oxidized glutathione concentrations were higher. There was significant colinearity between plasma saturated FAs, indicative of their metabolic relationships. Higher levels of the saturated FAs C18:0 and C24:0 were associated with lower TGF‐β1 concentrations, and higher C16:0 were associated with higher TNF‐α concentrations. We further examined effects of the aging FA profile on monocyte polarization and metabolism in THP1 monocytes. Monocytes preincubated with C16:0 increased secretion of pro‐inflammatory cytokines in response to phorbol myristate acetate‐induced differentiation through ceramide‐dependent inhibition of PPARγ activity. Conversely, C18:1 primed a pro‐resolving macrophage which was PPARγ dependent and ceramide dependent and which required oxidative phosphorylation. These data suggest that a midlife adult FA profile impairs the switch from proinflammatory to lower energy, requiring anti‐inflammatory macrophages through metabolic reprogramming.     

Effectiveness of mid-infrared spectroscopy to predict fatty acid composition of Brown Swiss bovine milk

Mid-infrared spectroscopy (MIR) is used to predict fatty acid (FA) composition of individual milk samples (n=267) of Brown Swiss cows. FAs were analyzed by gas chromatography as a reference method. Samples were scanned (4000 to 900 cm-1) by MIR, and predictive models were developed using modified partial least squares regressions with full cross-validation. The methods using a first derivative or multiplicative scatter corrected plus first derivative resulted, on average, in the best predictions. Coefficients of correlation between measured and predicted C8:0, C10:0, C12:0, C14:0, anteiso-C17:0, c9-C18:1, and medium- and long-chain FA, and saturated, monounsaturated and unsaturated FA ranged from 0.71 to 0.77, suggesting that prediction models can be implemented in milk recording schemes to routinely collect information on FA composition from the whole Brown Swiss population for breeding purposes.     

Effect of age on the fatty acid content of Blumeria graminis conidia

Blumeria (=Erysiphe) graminis f.sp. tritici (Bgt), the causal agent of wheat powdery mildew, is responsible for an important disease leading to considerable yield reductions in wheat worldwide. Conidia of the obligate plant pathogen Bgt were analysed for their total fatty acid (FA) composition as a function of their ontogeny. A total of 17 FAs were detected (C(12)-C(24) saturated and unsaturated ones), including the presence of unusual long-chain monoenoic FAs. In young conidia, the major FAs were C(18:2) (23%), C(16:0) (16%), C(18:0) (15.2%) and C(18:1) (14.3%). In old conidia, the main FAs were C(24:1) (20.7%), C(22:0) (15%), C(22:1) (13.5%) and C(24:0) (9.7%). The amount of total FA was about 39 microg.mg of dry weight(-1) in young conidia and decreased clearly to 18 microg.mg of dry weight(-1) in older conidia. For the first time, we have demonstrated that the FA composition of conidia changes greatly with age. Medium-chain FAs (C(12)-C(18)) are predominant in very young conidia (75%), whereas long-chain FAs (C(22)-C(24)) are the major compounds in old conidia (74%). This study showed a significant elongation of FAs and a drastic decrease in the total FA amount during the ontogeny of conidia.     

Limitations in the use of 3-hydroxy fatty acid analysis to determine endotoxin in mammalian samples

3-Hydroxy fatty acids (3-OH FAs) of 10–18-carbon chain lengths are constituents of the lipopolysaccharide of Gram-negative bacteria. These acids are used as chemical markers for determining endotoxin in environmental samples. The present communication addresses the question whether this type of analysis also would be applicable to mammalian samples. Low levels (6.1±1.6–94.0±23.2 pmol/ml) of the studied 3-OH FAs were detected in blood from both conventional and germ-free rats. The levels were considerably higher (0.0–1.06±0.17 nmol/mg) in livers. The amounts of the 3-OH FAs did not differ between the two groups of rats. All analyses were made by gas chromatography–tandem mass spectrometry (GC–MSMS) for unequivocal identification. The results illustrate a limitation in using 3-OH FA analysis to determine endotoxin in mammalian samples since these acids may represent not only endotoxin but also products from mammalian mitochondrial fatty acid β-oxidation.     

Fatty acids from the sponge Halichondria panicea from the Sea of Japan

The fatty acid (FA) composition of total lipids isolated from the marine sponge Halichondria panicea inhabiting Peter the Great Bay of Sea of Japan was studied. GC and GC-MS techniques helped identify 63 FAs, with the main attention being paid to FAs with 14-22 carbon atoms. 4, 8, 12-Trimethyl-13:0 FA was for the first time identified as the main saturated FA along with the branched FAs br-25:1, br-27:1, and br-27:2. The contents of arachidonic, eicosapentaenoic, docosapentaenoic, and the major demospongic acids [26:3(5, 9, 19), 26:3(5, 9, 17), 27:3(5, 9, 20), and 28:3(5, 9, 21)] considerably differed from those previously found for H. panicea, which may be due to seasonal changes in the species composition of organisms consumed by the sponge.     

Characterization of Aspergillus species based on fatty acid profiles

Cellular fatty acid (FA) composition was utilized as a taxonomic tool to discriminate between different Aspergillus species. Several of the tested species had the same FA composition and different relative FA concentrations. The most important FAs were palmitic acid (C16:0), estearic acid (C18:0), oleic acid (C18:1) and linoleic acid (C18:2), which represented 95% of Aspergillus FAs. Multivariate data analysis demonstrated that FA analysis is a useful tool for differentiating species belonging to genus Aspergillus. All the species analyzed showed significantly FA acid profiles (p < 0.001). Furthermore, it will be possible to distinguish among Aspergillus spp. in the Flavi Section. FA composition can serve as a useful tool for the identification of filamentous fungi.     

Endothelial lipase releases saturated and unsaturated fatty acids of high density lipoprotein phosphatidylcholine

We assessed the ability of endothelial lipase (EL) to hydrolyze the sn-1 and sn-2 fatty acids (FAs) from HDL phosphatidylcholine. For this purpose, reconstituted discoidal HDLs (rHDLs) that contained free cholesterol, apolipoprotein A-I, and either 1-palmitoyl-2-oleoylphosphatidylcholine, 1-palmitoyl-2-linoleoylphosphatidylcholine, or 1-palmitoyl-2-arachidonylphosphatidylcholine were incubated with EL- and control (LacZ)-conditioned media. Gas chromatography analysis of the reaction mixtures revealed that both the sn-1 (16:0) and sn-2 (18:1, 18:2, and 20:4) FAs were liberated by EL. The higher rate of sn-1 FA cleavage compared with sn-2 FA release generated corresponding sn-2 acyl lyso-species as determined by MS analysis. EL failed to release sn-2 FA from rHDLs containing 1-O-1'-hexadecenyl-2-arachidonoylphosphatidylcholine, whose sn-1 position contained a nonhydrolyzable alkyl ether linkage. The lack of phospholipase A(2) activity of EL and its ability to liberate [(14)C]FA from [(14)C]lysophosphatidylcholine (lyso-PC) led us to conclude that EL-mediated deacylation of phosphatidylcholine (PC) is initiated at the sn-1 position, followed by the release of the remaining FA from the lyso-PC intermediate. Thin-layer chromatography analysis of cellular lipids obtained from EL-overexpressing cells revealed a pronounced accumulation of [(14)C]phospholipid and [(14)C]triglyceride upon incubation with 1-palmitoyl-2-[1-(14)C]linoleoyl-PC-labeled HDL(3), indicating the ability of EL to supply cells with unsaturated FAs.     

Bioinformatic profiling of the transcriptional response of adult rat cardiomyocytes to distinct fatty acids

Diabetes mellitus, obesity, and dyslipidemia increase risk for cardiovascular disease, and expose the heart to high plasma fatty acid (FA) levels. Recent studies suggest that distinct FA species are cardiotoxic (e.g., palmitate), while others are cardioprotective (e.g., oleate), although the molecular mechanisms mediating these observations are unclear. The purpose of the present study was to investigate the differential effects of distinct FA species (varying carbon length and degree of saturation) on adult rat cardiomyocyte (ARC) gene expression. ARCs were initially challenged with 0.4 mM octanoate (8:0), palmitate (16:0), stearate (18:0), oleate (18:1), or linoleate (18:2) for 24 h. Microarray analysis revealed differential regulation of gene expression by the distinct FAs; the order regarding the number of genes whose expression was influenced by a specific FA was octanoate (1,188) > stearate (740) > palmitate (590) > oleate (83) > linoleate (65). In general, cardioprotective FAs (e.g., oleate) increased expression of genes promoting FA oxidation to a greater extent than cardiotoxic FAs (e.g., palmitate), whereas the latter induced markers of endoplasmic reticulum and oxidative stress. Subsequent RT-PCR analysis revealed distinct time- and concentration-dependent effects of these FA species, in a gene-specific manner. For example, stearate- and palmitate-mediated ucp3 induction tended to be transient (i.e., initial high induction, followed by subsequent repression), whereas oleate-mediated induction was sustained. These findings may provide insight into why diets high in unsaturated FAs (e.g., oleate) are cardioprotective, whereas diets rich in saturated FAs (e.g., palmitate) are not.     

Structure of the ceramide moiety of GM1 ganglioside determines its occurrence in different detergent-resistant membrane domains in HL-60 cells

To investigate the effect of the ceramide moiety of GM1 ganglioside on its association with detergent resistant membrane domains (DRMs) in human leukemia HL-60 cells, [(3)H] labeled GM1 molecular species (GM1s) with ceramides consisting of C18 sphingosine acetylated or acylated with C(8), C(12), C(14), C(16), C(18), C(22), C(24), C(18:1), C(22:1), or C(24:1) fatty acids (FAs), or C20 sphingosine acetylated or acylated with C(8) or C(18) FA were prepared and added to culture media. GM1s uptake by HL-60 cells was affected by the structure of their ceramides. Resistance to removal with trypsin and the stoichiometry of [(125)I] cholera toxin (CT) binding indicated that the added GM1s were incorporated into the membranes of the cells used for the isolation of DRMs in a manner resembling endogenous gangliosides. The ceramide moieties of the GM1s determined their occurrence in DRMs and the dependence of their recovery in this membrane fraction on the amount of Triton X-100 (TX) used for extraction as well as on cholesterol depletion. The GM1s with sphingosine acylated with C(14), C(16), C(18) C(22), or C(24) FAs were similarly abundant in DRMs. GM1s acylated with C(18:1), C(22:1), or C(24:1) were less abundant than those acylated with saturated FA of the same length. GM1s acetylated or acylated with C(8) FA were detected in DRMs in the lowest proportion. Depletion of 73% of cell cholesterol with methyl-beta-cyclodextrin significantly affected the recovery in DRMs of GM1s acetylated or acylated with C(8) or unsaturated FAs but not of GM1 acylated with C(18), C(22), or C(24) FAs. After cross-linking with CT B subunit, all GM1s were recovered in DRMs in a similarly high proportion irrespective of their ceramide structure or cholesterol depletion. DRMs prepared with low TX concentration at the TX/cell protein ratio of 0.3:1 were separated by multistep sucrose density gradient centrifugation into two fractions. The GM1s with sphingosine acetylated or acylated with C(18) or C(18:1) FAs occurred in these fractions in different proportions.     

Developmental changes in rat brain membrane lipids and fatty acids. The preferential prenatal accumulation of docosahexaenoic acid

Information on the prenatal accumulation of rat brain membrane lipids is scarce. In this study we investigated in detail the fatty acid (FA) composition of the rat brain, on each day from embryonic day 12 (E12) up to birth, and on 8 time points during the first 16 days of postnatal life, and correlated the FA changes with well-described events of neurogenesis and synaptogenesis. Between E14 and E17, there was a steep increase in the concentration of all the FAs: 16:0 increased by 136%, 18:0 by 139%, 18:1 by 92%, 20:4n-6 by 98%, 22:4n-6 by 116%, 22:5n-6 by 220%, and 22:6n-3 by 98%. After this period and up to birth, the concentration of the FAs plateaued, except that of 22:6n-3, which accumulated further, reaching an additional increase of 75%. After birth, except 22:5n-6, all FAs steadily increased at various rates. Estimation of the FA/PL molar ratios showed that prenatally the ratios of all the FAs either decreased or remained constant, but that of 22:6n-3 increased more than 2-fold; postnatally the ratios remained constant, with the exception of 22:4n-6 and 22:5n-6, which decreased. In conclusion, prenatal accumulation of brain fatty acids parallels important events in neurogenesis. 22:6n-3 is exceptional inasmuch in its steep accumulation occurs just prior to synaptogenesis.     

Effects of olive and fish oil Ca soaps in ewe diets on milk fat and muscle and subcutaneous tissue fatty-acid profiles of suckling lambs

Enhancing healthy fatty acids (FAs) in ewe milk fat and suckling lamb tissues is an important objective in terms of improving the nutritional value of these foods for the consumer. The present study examined the effects of feeding-protected lipid supplements rich in unsaturated FAs on the lipid composition of ewe milk, and subsequently in the muscle and subcutaneous adipose tissues of lambs suckling such milk. Thirty-six pregnant Churra ewes with their new-born lambs were assigned to one of three experimental diets (forage/concentrate ratio 50 : 50), each supplemented with either 3% Ca soap FAs of palm (Control), olive (OLI) or fish (FO) oil. The lambs were nourished exclusively by suckling for the whole experimental period. When the lambs reached 11 kg BW, they were slaughtered and samples were taken from the Longissimus dorsi and subcutaneous fat depots. Although milk production was not affected by lipid supplementation, the FO diet decreased fat content (P<0.001), whereas the OLI milk FA profile resembled that of the Control diet. In contrast, although FO drastically diminished the contents of stearic and oleic acids (P<0.001), all the saturated even-numbered carbon FAs from 6:0 to 14:0 increased (P<0.05). FO also produced the highest levels of c9,t11-18:2 (2.21%) and n-3 FAs, 20:5 n-3 (0.58%), 22:5 n-3 (0.48%) and 22:6 n-3 (0.40%). The high levels of trans-11 18:1 (7.10%) obtained from the FO diet would suggest that Ca soaps only confer partial protection in the rumen. In contrast, the lack of significant differences in trans-10 18:1 levels (P>0.05) and other trans-FAs between Control and FO treatments would indicate that FO treatment does not alter rumen biohydrogenation pathways under the assayed conditions. Changes in dam milk FA composition induced differences in the FA profiles of meat and fat depots of lambs, preferentially incorporated polyunsaturated FAs into the muscle rather than storing them in the adipose tissue. In the intramuscular fat of the FO treatment, all the n-3 FAs reached their highest concentrations: 0.97 (18:3 n-3), 2.72 (20:5 n-3), 2.21 (22:5 n-3) and 1.53% (22:6 n-3). In addition, not only did FO intramuscular fat have the most cis-9, trans-11 18:2 (1.66%) and trans-11 18:1 (3.75%), but also the lowest n-6/n-3 ratio (1.80) and saturated FA content were not affected. Therefore, FO exhibited the best FA profile from a nutritional point of view.     

Fatty acid composition in adductor muscle of juvenile scallops (Pecten maximus) from five Norwegian populations reared in the same environment

Adductor muscle fatty acid (FA) composition was compared in Pecten maximus juveniles originating from five locations along the Norwegian coast from 59°N to 65°N to detect possible population differences. Broodstock sized scallops were translocated to sea conditions by a scallop hatchery near Bergen (60°N) before spawning in February 2006. The scallop larvae and juveniles were reared in the same environment for two years and 10 individuals from each population were sampled in May 2007 and in May 2008 for analysis of the FAs in the adductor muscle. The total lipid content determined as total amount of FAs were 5.7 ± 0.3 mg per g tissue, and no significant difference was found among the five populations. The polyunsaturated FAs made up close to 60% of the total, with 20:5n3 and 22:6n3 dominating. The saturated FA content was approximately 30%, while the monounsaturated FA were less abundant (7–10%). The FA composition of the muscles of the five populations was similar within each year, with larger differences between the years. Multivariate, supervised learning method PLS, applied pairwise, showed distinct FA composition, between the scallops from the five locations, indicating population differences. The relatedness between the populations was different in the two years, but the distinct FA profiles of the adductor muscle could be used to distinguish between scallop populations on a local scale. The results indicate habitat-specific lipid metabolism which may have important implications for the scallop aquaculture industry in the context of producing well adapted individuals for the specific locations.     

Fatty acids in common minke whale (Balaenoptera acutorostrata) blubber reflect the feeding area and food selection,but also high endogenous metabolism

The fatty acid (FA) composition has been analysed in the blubber of 56 minke whales caught during the Norwegian commercial whaling period in 2009–2011. Minke whales from four regions were sampled: the North Sea, Vesterålen, Spitsbergen/Bear Island and Finnmark. The FA profiles of the whale blubber have been compared with FA profiles of potential prey species to investigate if FA analysis can be used to predict the diet of minke whales and how the FA profiles of the blubber reflect the regional ecosystem in which the whales were caught. Clear differences in blubber FA profiles were found between minke whales from different areas, and the results of the present study show that FA analysis of the blubber can be used to indicate the whale's diet, but there appears to be a strong impact from metabolism on several FAs. The whale blubber FAs are separate from those of the prey by having relatively high levels of FAs likely to originate from endogenous metabolism, such as 18:1n9 (Δ9-desaturation of 18:0); chain shortening products of 22:1(n-11); 20:1(n-11) and 18:1(n-11); as well as 22:5(n-3), which is an elongation product of 20:5(n-3). High metabolic activity in the adipose tissue was also evident by the clear stratification of FA profiles found throughout the blubber layer. It is remarkable that the whale blubber has much lower levels of the long-chain PUFAs 20:5(n-3) and 22:6(n-3) than found in the prey organisms. It is likely that this results from selective partitioning of diet FAs between the storage lipids and membrane lipids.     

Cellular Lipid and Fatty Acid Compositions of Burkholderia pseudomallei Strains Isolated from Human and Environment in Viet Nam

Viet nam is known as an endemic area of melioidosis but its etiologic agent originated in Viet nam was not extensively studied. For the first time, we analyzed the cellular lipid and fatty acid compositions of 15 Vietnamese isolates of Burkholderia pseudomallei, 10 from humans and 5 from the environment. Cellular lipid compositions were analyzed by two-dimensional thin-layer chromatography on silica gel G plates. Cellular fatty acid methyl esters were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The major lipids in all the isolates were phosphatidylglycerol (PG), two forms of phosphatidylethanolamine (PE-1 and PE-2), and two forms of ornithine-containing lipid (OL-1 and OL-2). PE-1 contained non-hydroxy fatty acids at both sn-1 and ?2 positions, while PE-2 possessed 2-hydroxy fatty acids and non-hydroxy fatty acids in a ratio of 1: 1. Since snake venom phospholipase A₂ digestion of PE-2 liberated 2-hydroxy fatty acids, it was confirmed that these acids are at the sn-2 position of glycerol moiety. In both OL-1 and OL-2, amide-linked fatty acid was 3-hydroxy palmitic acid (3-OH-C16: 0), while ester-linked fatty acids were non-hydroxy acids in OL-1 and 2-hydroxy acids in OL-2. The total cellular fatty acid compositions of the test strains were characterized by the presence of 2-hydroxy palmitic (2-OH-C16: 0), 2-hydroxy hexadecenoic (2-OH-C16: 1), 2-hydroxy octadecenoic (2-OH-C18: 1), 2-hydroxy methylene octadecanoic (2-OH-C19CPA), 3-hydroxy myristic (3-OH-C14: 0) and 3-hydroxy palmitic (3-OH-C16: 0) acids. There were significant differences in the concentration of hexadecenoic (C16: 1), methylene hexadecanoic (C17CPA), octadecenoic (C18: 1) and methylene octadecanoic (C19CPA) acids among the Vietnamese isolates of B. pseudomallei. However, no significant difference was observed in cellular lipid and fatty acid components between strains of human and environmental origins.     

Use of 3-hydroxy fatty acid concentrations in a murine air pouch infection model as a surrogate marker for LPS activity: a feasibility study using environmental Burkholderia cenocepacia isolates

Using a murine hypodermic air pouch infection model designed to mimic the release of bacterial products at physiological levels, 3-hydroxy fatty acid (3-OH FA) and endotoxin unit levels from Burkholderia cenocepacia isolates were assessed. The B. cenocepacia environmental isolates (n = 35) survived in the hypodermic air pouch but did not invade across the peritoneal epithelial layer during a 72-h infection. For all 35 strains, when the molar ratio of C_14:0 3-OH FA to C_16:0 3-OH FA in the air pouch fluid wash samples was between 1.4 and 2.5, the concentrations of C_14:0 3-OH FA were correlated with the endotoxin unit levels. However, both surrogate markers exhibited different correlations to the inflammatory response. The linear regression coefficient was 0.4234 for C_14:0 3-OH FA concentrations vs. NO productions, 0.223 for endotoxin unit levels vs. NO productions, 0.5008 for C_14:0 3-OH FA concentrations vs. TNF-alpha productions and 0.2869 for endotoxin unit levels vs. TNF-alpha productions. Therefore, C_14:0 3-OH FA concentrations, rather than endotoxin unit levels, acted as an immunostimulatory indicator for LPS in the B. cenocepacia isolates.