Dynamic changes at high-protein dietary pattern of major fatty acids in healthy lactating women: A systematic review and meta-analysis

BACKGROUND

Fatty acids (FAs) in human milk are important nutrients for infants. They play important roles in energy supply, nervous system development, and metabolic function maintenance. However, how the composition of major milk FAs change with lactation stages remains controversial.

OBJECTIVES

To systematically review the concentration range of major FAs in human milk at various lactation stages.

METHODS

A total of 12 papers involving 50 sets of data with 3507 participants were reviewed according to the PRISMA checklist and flow diagram. The inclusion criteria was the literatures had the FAs contents in breast milk of healthy lactation mothers at three lactation stages and the dietary patterns could be calculated. The exclusion criteria were: the studies were duplicates, were unrelated to dietary patterns or breast milk composition, and/or the study populations were unhealthy. We searched PubMed, the China National Knowledge Infrastructure, WanFang, and Web of science. Agency for Health Care Research and Quality (AHRQ) was used to assess the bias of studies. The mean values of polyunsaturated fatty acids (PUFAs) including docosahexaenoic acid (DHA), arachidonic acid (AA), eicosapentaenoic acid (EPA), α-linolenic acid (ALA), linoleic acid (LA), monounsaturated fatty acids (MUFAs), and saturated fatty acids (SFAs, including lauric acid and palmitic acid), in human milk at three lactation stages (colostrum 1-7 d, transitional milk 8-14 d, mature milk 15 d-3 mo) of healthy lactating women were investigated in terms of the high protein dietary pattern. Publication biases were evaluated by Egger's test.

RESULTS

According to the percentage in total fat of colostrum, transitional milk, and mature milk (% wt/wt), respectively, the results showed that PUFA (25.72%, 24.92%, and 22.69%), AA (0.85%, 0.76%, and 0.59%), DHA (0.53%, 0.47%, and 0.39%), EPA (0.15%, 0.10%, and 0.10%), and MUFA (37.39%, 37.21%, and 36.14%) contents in breast milk decreased with lactation, while another two PUFA forms, LA (17.47%, 17.82%, and 17.48%), and ALA (1.09%, 1.39%, and 1.24%) arrived at a peak in the transitional milk and then decreased in the mature milk, SFA (37.46%, 38.64%, and 40.52%), and lauric acid contents (2.78%, 4.91%, and 4.97%) increased with the lactation stages.

CONCLUSION

These findings could shed light on the dynamic change progress of major FA metabolism, potentially enhancing the knowledge of lactation biology, and improving infant feeding practices to meet their needs.

Liglaurates A-E, cytotoxic bis(lauric acid-12yl)lignanoates from the rhizomes of Drynaria roosii Nakaike

Five undescribed bis(lauric acid-12-yl)lignanoates, liglaurates A-E, along with the known methyl and glyceryl 12-caffeoyloxylaurates were isolated from the rhizomes of Drynaria roosii Nakaike. Their structures including absolute configurations were determined by HRESIMS, NMR techniques, and ECD calculation. Liglaurates A-D were isolated as the racemates, among which (±)-liglaurate A and (±)-liglaurate B were synthesized by a metal-mediated oxidative coupling reaction and further resolved as the enantiomerically pure compounds. Liglaurates (+)-A, (-)-A, (+)-B, (-)-B, (±)-C and (±)-D exhibited remarkable cytotoxic activities against HeLa cell line, with the IC₅₀ values of 0.11 ± 0.02, 0.24 ± 0.01, 0.02 ± 0.00, 0.13 ± 0.02, 0.34 ± 0.07 and 0.17 ± 0.01 μM, respectively.

Perfluoroalkyl substances (PFASs) in air-conditioner filter dust of indoor microenvironments in Greece: Implications for exposure

The occurrence of perfluoroalkyl substances (PFASs) was for the first time investigated in various working microenvironments (internet cafes, electronics shops, coffee shops, restaurants, etc.) in Thessaloniki, Greece, using the dust trapped by central air conditioner (A/C) filters. Perfluorooctane sulfonic acid (PFOS) was found in the range from 16 to 227 ng g^-1, however it was detectable in only 30% of samples. On the contrary, perfluorohexanoic acid (PFHxA) was found in 85% of samples in the range from 3.6 to 72.5 ng g^-1, while 90-95% of samples exhibited perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDcA) and perfluorododecanoic acid (PFDoDA) in the range from 10-653 ng g^-1, 3.2-7.4 ng g^-1 and 3.8-13.1 ng g^-1, respectively. The PFAS profile varied largely among the different microenvironment categories suggesting different sources. Estimated daily intakes through dust ingestion were calculated.

Perfluoroalkyl substances (PFASs) in the marine environment: Spatial distribution and temporal profile shifts in shellfish from French coasts

Perfluoroalkyl substances (PFASs) were investigated in filter-feeding shellfish collected from 2013 to 2017 along the English Channel, Atlantic and Mediterranean coasts of France. PFOS (perfluorooctane sulfonate), PFTrDA (perfluorotridecanoic acid), PFTeDA (perfluorotetradecanoic acid), PFDoDA (perfluorododecanoic acid) and PFUnDA (perfluoroundecanoic acid) were detected in more than 80% of samples, thus indicating widespread contamination of the French coastal environment by these chemicals. The distribution of PFAS concentrations showed differences according to sampling locations and years. PFOS was the predominant PFAS in most samples collected from English Channel and Atlantic coasts until 2014, but the opposite was observed in 2015, 2016 and 2017, while perfluoroalkyl carboxylic acids (PFCAs) prevailed in Mediterranean samples in all study years. Among PFCAs, PFTrDA showed the highest maximum (1.36 ng g^-1 ww) and median (0.077 ng g^-1 ww) concentrations in 2016-2017. Other PFAS median concentrations were within the 0.014 (PFNA) - 0.055 (PFTeDA) ng g^-1 ww range. The profiles determined each year in most Mediterranean samples suggest distinctive sources. PFOS median concentrations showed a significant decrease over the study years, from 0.118 to 0.126 ng g^-1 ww in 2013-2015 to 0.066 ng g^-1 ww in 2016 and 2017. ∑PFCAs showed no trends in concentration ranges over the same years. The shift in PFAS profiles from PFOS to long-chain PFCAs over the study period reflects PFOS production phase-out, combined with continuous inputs of PFCAs into the marine environment. These results provide reference data for future studies of the occurrence of contaminants of emerging concern on European coasts.

Physicochemical characteristics of fat blend from hydrogenated coconut oil and acyl migrated palm mid-fraction

Palm mid-fraction (PMF), which has a high content of symmetric POP, was converted to asymmetric PPO (APMF) via acyl migration. After solvent fractionation, the liquid phase of acyl migrated PMF (APMF-L) was obtained and blended with hydrogenated coconut oil (HCO, 50:50, w/w) to produce a fat blend (namely, an alternative fat blend) which had reduced saturated fatty acid content while having similar melting behavior to HCO. In an alternative fat blend, the major fatty acids were lauric (27.94), palmitic (26.93) and oleic (15.75 mol%) acid. The solid fat index was quite similar to that of HCO, especially at 28-44 °C. Nevertheless, an alternative fat blend had lower saturated fatty acid content, by 18%, compared to HCO. The content of highly atherogenic myristic acid was reduced by approximately 40%. The alternative fat blend in this study could be used as a raw material for non-dairy cream with low saturated fat content.

Suitability of lemon balm (Melissa officinalis L.) extract rich in rosmarinic acid as a potential enhancer of functional properties in cupcakes

Melissa officinalis (lemon balm) and its extracts have been frequently reported as possessing bioactive properties, offering the potential for use in development/enrichment of food products with additional functional capabilities, providing health benefits to consumers. The antioxidant, antibacterial and antifungal activity of lemon balm extract, as well as its potential hepatotoxicity were thoroughly evaluated. The extracts were then incorporated into cupcakes and their preserving effect, chemical composition, colour parameters and antioxidant activity were compared with those provided by potassium sorbate. In general, the variables with the largest differences among different storage times were energy level, sucrose, glucose, palmitic acid (C6:0) and oleic acid (C18:1n9). On the other hand, L∗ (top), a∗ (top), b∗ (top), pH, capric acid (C10:0) and lauric acid (C12:0) showed the greatest variation according to cupcake formulation. The results observed indicate that the lemon balm extract rich in rosmarinic acid can provide advantageous functional properties to bakery products.

Coupling electrokinetics with microbial biodegradation enhances the removal of cycloparaffinic hydrocarbons in soils

An innovative approach that couples electrokinetics with microbial degradation to breakdown cycloparaffinic hydrocarbons in soils is described. Soils were spiked with cyclododecane, used as a model pollutant, at approximately 1000mgkg^-1. A mixture of petroleum-utilizing bacteria was added to achieve about 10⁶-10⁷ CFUg^-1. Then, three treatments were applied for 25 days: (1) no electric field, control; (2) a constant voltage gradient of 1.3Vcm^-1 in one direction; and (3) the same electric field, but with periodical switching of polarity. The degradation pathway of cyclododecane was not changed by the electric field, but the dynamic processes were remarkably enhanced, especially when the electric field was periodically switched. After 25 days, 79.9% and 87.0% of the cyclododecane was degraded in tests 2 and 3, respectively; both much higher than the 61.5% degraded in test 1. Analysis of the intermediate products strongly indicated that the competitive advantage of the electric field was the increase in ring-breaking of cyclododecane, resulting in greater concentrations of linear substances that were more susceptible to microbial attack, that is, β-oxidation. The conditions near the cathode were more favorable for the growth and metabolism of microorganisms, which also enhanced β-oxidation of the linear alkanoic acids. Therefore, when the electric field polarity was periodically switched, the functions of both the anode and cathode electrodes were applied across the whole soil cell, further increasing the degradation efficiency.

In Silico and Wet Lab Studies Reveal the Cholesterol Lowering Efficacy of Lauric Acid, a Medium Chain Fat of Coconut Oil

The coconut oil (CO) contains 91 % of saturated fatty acids in which 72 % are medium chain fatty acids (MCFAs) like lauric, capric and caprylic acids. In contrast to animal fat, coconut oil has no cholesterol. Despite this fact, CO is sidelined among other vegetable oils due to the health hazards attributed to the saturated fatty acids. Though various medicinal effects of CO have been reported including the hypolipidemic activity, people are still confused in the consumption of this natural oil. In silico analyses and wet lab experiments have been carried out to identify the hypolipidemic properties of MCFAs and phenolic acids in CO by using different protein targets involved in cholesterol synthesis. The molecular docking studies were carried out using CDOCKER protocol in Accelery's Discovery Studio, by taking different proteins like HMG- CoA reductase and cholesterol esterase as targets and the different phytocompounds in coconut as ligands. Molecular docking highlighted the potential of lauric acid in inhibiting the protein targets involved in hyperlipidemics. Further, validation of in silico results was carried out through in vivo studies. The activity of key enzymes HMG- CoA reductase and lipoprotein lipase were found reduced in animals fed with lauric acid and CO.

Chemical composition and allelopathic potential of essential oils obtained from Acacia cyanophylla Lindl. Cultivated in Tunisia

Acacia cyanophylla Lindl. (Fabaceae), synonym Acacia saligna (Labill.) H. L.Wendl., native to West Australia and naturalized in North Africa and South Europe, was introduced in Tunisia for rangeland rehabilitation, particularly in the semiarid zones. In addition, this evergreen tree represents a potential forage resource, particularly during periods of drought. A. cyanophylla is abundant in Tunisia and some other Mediterranean countries. The chemical composition of the essential oils obtained by hydrodistillation from different plant parts, viz., roots, stems, phyllodes, flowers, and pods (fully mature fruits without seeds), was characterized for the first time here. According to GC-FID and GC/MS analyses, the principal compound in the phyllode and flower oils was dodecanoic acid (4), representing 22.8 and 66.5% of the total oil, respectively. Phenylethyl salicylate (8; 34.9%), heptyl valerate (3; 17.3%), and nonadecane (36%) were the main compounds in the root, stem, and pod oils, respectively. The phyllode and flower oils were very similar, containing almost the same compounds. Nevertheless, the phyllode oil differed from the flower oil for its higher contents of hexahydrofarnesyl acetone (6), linalool (1), pentadecanal, α-terpineol, and benzyl benzoate (5) and its lower content of 4. Principal component and hierarchical cluster analyses separated the five essential oils into four groups, each characterized by its main constituents. Furthermore, the allelopathic activity of each oil was evaluated using lettuce (Lactuca sativa L.) as a plant model. The phyllode, flower, and pod oils exhibited a strong allelopathic activity against lettuce.

Bioaccumulation of perfluoroalkyl acids by earthworms (Eisenia fetida) exposed to contaminated soils

The presence of perfluoroalkyl acids (PFAAs) in biosolids-amended and aqueous film-forming foam (AFFF)-impacted soils results in two potential pathways for movement of these environmental contaminants into terrestrial foodwebs. Uptake of PFAAs by earthworms (Eisenia fetida) exposed to unspiked soils with varying levels of PFAAs (a control soil, an industrially impacted biosolids-amended soil, a municipal biosolids-amended soil, and two AFFF-impacted soils) was measured. Standard 28 day exposure experiments were conducted in each soil, and measurements taken at additional time points in the municipal soil were used to model the kinetics of uptake. Uptake and elimination rates and modeling suggested that steady state bioaccumulation was reached within 28 days of exposure for all PFAAs. The highest concentrations in the earthworms were for perfluorooctane sulfonate (PFOS) in the AFFF-impacted Soil A (2160 ng/g) and perfluorododecanoate (PFDoA) in the industrially impacted soil (737 ng/g). Wet-weight (ww) and organic carbon (OC)-based biota soil accumulation factors (BSAFs) for the earthworms were calculated after 28 days of exposure for all five soils. The highest BSAF in the industrially impacted soil was for PFDoA (0.42 goc/gww,worm). Bioaccumulation factors (BAFs, dry-weight-basis, dw) were also calculated at 28 days for each of the soils. With the exception of the control soil and perfluorodecanoate (PFDA) in the industrially impacted soil, all BAF values were above unity, with the highest being for perfluorohexanesulfonate (PFHxS) in the AFFF-impacted Soil A (139 gdw,soil/gdw,worm). BSAFs and BAFs increased with increasing chain length for the perfluorocarboxylates (PFCAs) and decreased with increasing chain length for the perfluoroalkyl sulfonates (PFSAs). The results indicate that PFAA bioaccumulation into earthworms depends on soil concentrations, soil characteristics, analyte, and duration of exposure, and that accumulation into earthworms may be a potential route of entry of PFAAs into terrestrial foodwebs.

Estimating human exposure to PFOS isomers and PFCA homologues: the relative importance of direct and indirect (precursor) exposure

Contributions of direct and indirect (via precursors) pathways of human exposure to perfluorooctane sulfonic acid (PFOS) isomers and perfluoroalkyl carboxylic acids (PFCAs) are estimated using a Scenario-Based Risk Assessment (SceBRA) modelling approach. Monitoring data published since 2008 (including samples from 2007) are used. The estimated daily exposures (resulting from both direct and precursor intake) for the general adult population are highest for PFOS and perfluorooctanoic acid (PFOA), followed by perfluorohexanoic acid (PFHxA) and perfluorodecanoic acid (PFDA), while lower daily exposures are estimated for perfluorobutanoic acid (PFBA) and perfluorododecanoic acid (PFDoDA). The precursor contributions to the individual perfluoroalkyl acid (PFAA) daily exposures are estimated to be 11-33% for PFOS, 0.1-2.5% for PFBA, 3.7-34% for PFHxA, 13-64% for PFOA, 5.2-66% for PFDA, and 0.7-25% for PFDoDA (ranges represent estimated precursor contributions in a low- and high-exposure scenario). For PFOS, direct intake via diet is the major exposure pathway regardless of exposure scenario. For PFCAs, the dominant exposure pathway is dependent on perfluoroalkyl chain length and exposure scenario. Modelled PFOS and PFOA concentrations in human serum using the estimated intakes from an intermediate-exposure scenario are in agreement with measured concentrations in different populations. The isomer pattern of PFOS resulting from total intakes (direct and via precursors) is estimated to be enriched with linear PFOS (84%) relative to technical PFOS (70% linear). This finding appears to be contradictory to the observed enrichment of branched PFOS isomers in recent human serum monitoring studies and suggests that either external exposure is not fully understood (e.g. there are unknown precursors, missing or poorly quantified exposure pathways) and/or that there is an incomplete understanding of the isomer-specific human pharmacokinetic processes of PFOS, its precursors and intermediates.

Multiplexed analysis of cage and cage free chicken egg fatty acids using stable isotope labeling and mass spectrometry

Binary stable isotope labeling couple with LC-ESI-MS has been used as a powerful non-targeted approach for the relative quantification of lipids, amino acids, and many other important metabolite classes. A multiplexed approach using three or more isotopic labeling reagents greatly reduces analytical run-time while maintaining excellent sensitivity and reproducibility. Three isotopic cholamine labeling reagents have been developed to take advantage of the pre-ionized character of cholamine, for ESI, and the ease by which stable isotopes can be incorporated into the cholamine structure. These three cholamine labeling reagents have been used to relatively quantify three fatty acid samples simultaneously. The quantification resulted in the observation of 12 fatty acids that had an average absolute error of 0.9% and an average coefficient of variation of 6.1%. Caged versus cage-free isotope labeling experiments showed that cage-free eggs have an increased level of omega-3 fatty acids as compared to caged eggs. This multiplexed fatty acid analysis provides an inexpensive and expedited tool for broad-based lipid profiling that will further aid discoveries in the mechanisms of fatty acid action in cells.

Effect of cerium oxide nanoparticles on the quality of rice ( Oryza sativa L.) grains

Despite the remarkable number of publications on the interaction of engineered nanoparticles (ENPs) with plants, knowledge of the implications of ENPs in the nutritional value of food crops is still limited. This research was performed to study the quality of rice grains harvested from plants grown in soil treated with cerium oxide nanoparticles (nCeO2). Three rice varieties (high, medium, and low amylose) were cultivated to full maturity in soil amended with nCeO2 at 0 and 500 mg kg(-1) soil. Ce accumulation, nutrient content, antioxidant property, and nutritional quality of the rice grains were evaluated. Results showed that rice grains from nCeO2-treated plants had less Fe, S, prolamin, glutelin, lauric and valeric acids, and starch. Moreover, the nCeO2 reduced in grains all antioxidant values, except flavonoids. Medium- and low-amylose varieties accumulated more Ce in grains than the high-amylose variety, but the grain quality of the medium-amylose variety showed higher sensitivity to the nCeO2 treatment. These results indicate that nCeO2 could compromise the quality of rice. To the authors' knowledge, this is the first report on the effects nCeO2 on rice grain quality.

Comparative transcriptome analysis of three oil palm fruit and seed tissues that differ in oil content and fatty acid composition

Oil palm (Elaeis guineensis) produces two oils of major economic importance, commonly referred to as palm oil and palm kernel oil, extracted from the mesocarp and the endosperm, respectively. While lauric acid predominates in endosperm oil, the major fatty acids (FAs) of mesocarp oil are palmitic and oleic acids. The oil palm embryo also stores oil, which contains a significant proportion of linoleic acid. In addition, the three tissues display high variation for oil content at maturity. To gain insight into the mechanisms that govern such differences in oil content and FA composition, tissue transcriptome and lipid composition were compared during development. The contribution of the cytosolic and plastidial glycolytic routes differed markedly between the mesocarp and seed tissues, but transcriptional patterns of genes involved in the conversion of sucrose to pyruvate were not related to variations for oil content. Accumulation of lauric acid relied on the dramatic up-regulation of a specialized acyl-acyl carrier protein thioesterase paralog and the concerted recruitment of specific isoforms of triacylglycerol assembly enzymes. Three paralogs of the WRINKLED1 (WRI1) transcription factor were identified, of which EgWRI1-1 and EgWRI1-2 were massively transcribed during oil deposition in the mesocarp and the endosperm, respectively. None of the three WRI1 paralogs were detected in the embryo. The transcription level of FA synthesis genes correlated with the amount of WRI1 transcripts and oil content. Changes in triacylglycerol content and FA composition of Nicotiana benthamiana leaves infiltrated with various combinations of WRI1 and FatB paralogs from oil palm validated functions inferred from transcriptome analysis.

Determination of thermodynamic and transport parameters of naphthenic acids and organic process chemicals in oil sand tailings pond water

Oil sand tailings pond water contains naphthenic acids and process chemicals (e.g., alkyl sulphates, quaternary ammonium compounds, and alkylphenol ethoxylates). These chemicals are toxic and can seep through the foundation of the tailings pond to the subsurface, potentially affecting the quality of groundwater. As a result, it is important to measure the thermodynamic and transport parameters of these chemicals in order to study the transport behavior of contaminants through the foundation as well as underground. In this study, batch adsorption studies and column experiments were performed. It was found that the transport parameters of these chemicals are related to their molecular structures and other properties. The computer program (CXTFIT) was used to further evaluate the transport process in the column experiments. The results from this study show that the transport of naphthenic acids in a glass column is an equilibrium process while the transport of process chemicals seems to be a non-equilibrium process. At the end of this paper we present a real-world case study in which the transport of the contaminants through the foundation of an external tailings pond is calculated using the lab-measured data. The results show that long-term groundwater monitoring of contaminant transport at the oil sand mining site may be necessary to avoid chemicals from reaching any nearby receptors.

Comparative transcriptome analysis of three oil palm fruit and seed tissues that differ in oil content and fatty acid composition

Oil palm (Elaeis guineensis) produces two oils of major economic importance, commonly referred to as palm oil and palm kernel oil, extracted from the mesocarp and the endosperm, respectively. While lauric acid predominates in endosperm oil, the major fatty acids (FAs) of mesocarp oil are palmitic and oleic acids. The oil palm embryo also stores oil, which contains a significant proportion of linoleic acid. In addition, the three tissues display high variation for oil content at maturity. To gain insight into the mechanisms that govern such differences in oil content and FA composition, tissue transcriptome and lipid composition were compared during development. The contribution of the cytosolic and plastidial glycolytic routes differed markedly between the mesocarp and seed tissues, but transcriptional patterns of genes involved in the conversion of sucrose to pyruvate were not related to variations for oil content. Accumulation of lauric acid relied on the dramatic up-regulation of a specialized acyl-acyl carrier protein thioesterase paralog and the concerted recruitment of specific isoforms of triacylglycerol assembly enzymes. Three paralogs of the WRINKLED1 (WRI1) transcription factor were identified, of which EgWRI1-1 and EgWRI1-2 were massively transcribed during oil deposition in the mesocarp and the endosperm, respectively. None of the three WRI1 paralogs were detected in the embryo. The transcription level of FA synthesis genes correlated with the amount of WRI1 transcripts and oil content. Changes in triacylglycerol content and FA composition of Nicotiana benthamiana leaves infiltrated with various combinations of WRI1 and FatB paralogs from oil palm validated functions inferred from transcriptome analysis.

[Changes in the content of plasma lipoproteins in persons subjected to diets prepared with sunflower oil alone or mixed with palm olein]

We analyzed in 31 subjects, regular guests of the University food service of the Central University of Venezuela (UCVFS), in Caracas, the effects of replacing sunflower oil, commonly used in the preparation of meals, by a mix of sunflower oil and palm olein 70/30 (v/v) respectively. Plasma concentrations of total cholesterol, low and very low density lipoproteins were not changed after 40 days of the substitution. On the contrary, concentrations of high density lipoprotein and total triglycerides increased. The resistance to the oxidation of low-density lipoproteins increased considerably (p < 0.01). Today this resistance is considered as a protective factor of great importance in the prevention of the initiation of the atherogenic process. Taking into account the favorable modifications of HDL cholesterol and the clear increased resistance to the oxidation of LDL, we think that palm olein, mixed with other oils with a high ratio linoleic/palmitic (sunflower, corn, soya an the likes), can be used as a healthy alternative in human nutrition.

Fatty acids and bioactive compounds of the pulps and kernels of Brazilian palm species, guariroba (Syagrus oleraces), jerivá (Syagrus romanzoffiana) and macaúba (Acrocomia aculeata)

BACKGROUND

Bioactive compounds are capable of providing health benefits, reducing disease incidence or favoring body functioning. There is a growing search for vegetable oils containing such compounds. This study aimed to characterize the pulp and kernel oils of the Brazilian palm species guariroba (Syagrus oleracea), jerivá (Syagrus romanzoffiana) and macaúba (Acrocomia aculeata), aiming at possible uses in several industries.

RESULTS

Fatty acid composition, phenolic and carotenoid contents, tocopherol composition were evaluated. The majority of the fatty acids in pulps were oleic and linoleic; macaúba pulp contained 526 g kg⁻¹ of oleic acid. Lauric acid was detected in the kernels of all three species as the major saturated fatty acid, in amounts ranging from 325.8 to 424.3 g kg⁻¹. The jerivá pulp contained carotenoids and tocopherols on average of 1219 µg g⁻¹ and 323.50 mg kg⁻¹, respectively.

CONCLUSION

The pulps contained more unsaturated fatty acids than the kernels, mainly oleic and linoleic. Moreover, the pulps showed higher carotenoid and tocopherol contents. The kernels showed a predominance of saturated fatty acids, especially lauric acid. The fatty acid profiles of the kernels suggest that these oils may be better suited for the cosmetic and pharmaceutical industries than for use in foods.

Perfluorinated compounds in water, sediment and soil from Guanting Reservoir, China

Concentrations of 12 perfluorinated compounds (PFCs) were measured in 21 representive water, sediment and soil samples from Guanting Reservoir and vicinity. Perfluorooctanoic acid (PFOA) was the predominant PFCs with concentrations of 0.55-2.3 ng/L, <LOQ to 0.68 ng/g dw and <LOQ to 2.8 ng/g dw in water, sediment and soil, respectively. Perfluorododecanoic acid (PFDoA) was frequently detected in solid matrices, with concentrations of <LOQ to 0.18 ng/g dw in sediment and 0.13-0.26 ng/g dw in soil. PFCs were detected in all environmental matrices sampled, but concentrations found throughout the watershed were less than those reported from other locations.

Concentrations, distribution, and persistence of perfluoroalkylates in sludge-applied soils near Decatur, Alabama, USA

Sludges generated at a wastewater treatment plant (WWTP) in Decatur, Alabama have been applied to agricultural fields for more than a decade. Waste-stream sources to this WWTP during this period included industries that work with fluorotelomer compounds, and sludges from this facility have been found to be elevated in perfluoroalkylates (PFAs). With this knowledge, the U.S. Environmental Protection Agency collected soil samples from sludge-applied fields as well as nearby "background" fields for PFA analysis. Samples from the sludge-applied fields had PFAs at much higher concentrations than in the background fields; generally the highest concentrations were perfluorodecanoic acid (≤ 990 ng/g), perfluorododecanoic acid (≤ 530 ng/g), perfluorooctanoic acid (≤ 320 ng/g), and perfluorooctane sulfonate (≤ 410 ng/g). Contrasts in PFA concentration between surface and deeper soil samples tended to be more pronounced in long-chain congeners than shorter chains, perhaps reflecting relatively lower environmental mobilities for longer chains. Several PFAs were correlated with secondary fluorotelomer alcohols (sec-FTOHs) suggesting that PFAs are being formed by degradation of sec-FTOHs. Calculated PFA disappearance half-lives for C6 through C11 alkylates ranged from about 1 to 3 years and increase with increasing chain-length, again perhaps reflecting lower mobility of the longer-chained compounds.

[Analysis of fatty acids from the flowers of Trollius chinensis]

OBJECTIVE

To analyze and identify fatty acids from the flowers of Trollius chinensis Bunge.

METHODS

To isolate and determine the constituents using GC/MS technique, quantitatively analyze their content by area normalization method.

RESULTS

31 fatty acids and 7 other constituents were isolated and determined.

CONCLUSION

The major fatty acids were hexadecanoic (19.85%), (Z,Z)-9,12-octadecadienoic (14.37%), tetradecanoic (13.93%), (Z)-9-octadecenoic (13.00%), dodecanoic (6.79%), 10-hydroxy-hexadecanoic (4.37%) and octadecanoic (3.34%) acids.

Perfluorinated compounds in urban river sediments from Guangzhou and Shanghai of China

Perfluorinated compounds (PFCs) have been determined in various matrices within China including water bodies, precipitations, biota and non-occupationally PFCs-exposed populations in recent years, yet little attention has been focused on the distributions of PFCs in urban river sediments from Chinese major metropolises such as Guangzhou and Shanghai so far. In this study, sediment samples of 0-2 cm were collected from 13 sites in the Zhujiang River across Guangzhou and nine sites in the Huangpu River across Shanghai. PFCs analysis on these sediments via high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) system was implemented targeting eight analytes involving perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoA) and perfluorotetradecanoic acid (PFTA). According to the analytical results, total concentrations of PFCs ([summation operator]PFCs) in sediments from the Zhujiang River were between 0.09 and 3.6 ng/g dry weight (dw), with PFOS being the dominant PFC contaminant in the river ranged from below LOD to 3.1 ng/g dw; while [summation operator]PFCs in sediments from the Huangpu River were between 0.25 and 1.1 ng/g dw, with PFOA being the main PFC contaminant in the river determined in the levels of 0.20-0.64 ng/g dw. Additionally, an overall decreasing trend of PFCs contaminations with depth was observed in both of two 60 cm sediment cores from the Zhujiang River and the Huangpu River each.

Perfluorinated compounds in sediments from the Daliao River system of northeast China

Perfluorinated compounds (PFCs) have received much attention on their distributions in various matrixes of different areas globally, however, little is known about their existences in river sediments of China. In this study, eight target PFCs including perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoA) and perfluorotetradecanoic acid (PFTA) were determined based upon the upper 10cm surface sediment samples collected from eleven sites covering three main streams of the Daliao River system in northeast China, which received huge amount of industrial and domestic wastewater annually from the neighbouring areas. Analytical results indicated that total concentrations of PFCs were determined in the range of 0.29-1.03ngg(-1) dry weight in sediments from this river system. As the dominant PFCs contaminants in sediment samples, concentrations of PFOS and PFOA were ranged between <LOQ and 0.37ngg(-1) dry weight and from <LOQ to 0.17ngg(-1) dry weight, respectively, while those of the other six target analytes relating to PFBS, PFHxS, PFNA, PFDA, PFDoA and PFTA were below their LOQs at most of the sampling sites. Additional analyses on vertical variations of total PFCs concentrations in sectioned sediment core samples from three main streams of this river system presented overall decreasing trends of PFCs contaminations with depth in the top 10cm surface sediments of these rivers.

Detecting the quality of glycerol monolaurate: a method for using Fourier transform infrared spectroscopy with wavelet transform and modified uninformative variable elimination

Glycerol monolaurate (GML) products contain many impurities, such as lauric acid and glucerol. The GML content is an important quality indicator for GML production. A hybrid variable selection algorithm, which is a combination of wavelet transform (WT) technology and modified uninformative variable eliminate (MUVE) method, was proposed to extract useful information from Fourier transform infrared (FT-IR) transmission spectroscopy for the determination of GML content. FT-IR spectra data were compressed by WT first; the irrelevant variables in the compressed wavelet coefficients were eliminated by MUVE. In the MUVE process, simulated annealing (SA) algorithm was employed to search the optimal cutoff threshold. After the WT-MUVE process, variables for the calibration model were reduced from 7366 to 163. Finally, the retained variables were employed as inputs of partial least squares (PLS) model to build the calibration model. For the prediction set, the correlation coefficient (r) of 0.9910 and root mean square error of prediction (RMSEP) of 4.8617 were obtained. The prediction result was better than the PLS model with full-spectra data. It was indicated that proposed WT-MUVE method could not only make the prediction more accurate, but also make the calibration model more parsimonious. Furthermore, the reconstructed spectra represented the projection of the selected wavelet coefficients into the original domain, affording the chemical interpretation of the predicted results. It is concluded that the FT-IR transmission spectroscopy technique with the proposed method is promising for the fast detection of GML content.

Analysis of the hydrodistillate from the fruits of Serenoa repens

The chemical composition of the hydrodistillate won by steam distillation from the fruits of Serenoa repens (W. Bartram), a well known phytomedicine against benign prostatic hyperplasia (BPH), was analyzed by GC-MS. It resulted in the identification of 144 steam-volatile components including about 100 structures which have not been described as constituents of the fruits from S. repens so far. The main component detected was lauric acid (40.4 %).

[Analysis of chemical constituents of the volatile oil from flowers of Oyster Rhoeo by GC/MS]

OBJECTIVE

To analyze the chemical constituents of the volatile oil from the flowers of Oyster Rhoeo.

METHODS

The volatile oil from the flower of Oyster Rhoeo was extracted by steam distillation and its chemical constituents were analyzed by GC/MS technique.

RESULTS

All 20 compounds which relative content was greater than 0.3% were identified, accounting for 90.24% of the volatile oil.

CONCLUSION

The major constituent of the volatile oil is nonaldehyde (25.72%), the other main constituents are hexadecanoid acid (22.79%), nonanoic acid (18.94%), dodecanoic acid (7.72%), isovanillin (2.84%), heptanoic acid (2.20%), octanoic acid (1.89%) and linoleic acid (1.71%), respectively.

A microfluidic platform for integrated synthesis and dynamic light scattering measurement of block copolymer micelles

Microfluidic devices were developed that integrate the synthesis of well defined block copolymers and dynamic light scattering (DLS) measurement of their micelle formation. These metal devices were designed to operate in contact with organic solvents and elevated temperatures for long periods, and thus were capable of continuous in-channel atom transfer radical polymerization (ATRP) of styrene and (meth)acrylate homopolymers and block copolymers. These devices were equipped with a miniaturized fiber optic DLS probe that included several technology improvements, including a measurement volume of only 4 microlitres, simple alignment, and reduced multiple scattering. To demonstrate the integrated measurement, poly(methyl methacrylate-b-lauryl methacrylate) and poly(methyl methacrylate-b-octadecyl methacrylate) block copolymers were processed on the device with a selective solvent, dodecane, to induce micelle formation. The in situ DLS measurements yielded the size and aggregation behavior of the micelles. For example, the block copolymer solutions formed discrete micelles (D(H) approximately = 25 nm) when the corona block was sufficiently long (f(MMA) < 0.51), but the micelles aggregated when this block was short. This study demonstrates the utility of these new devices for screening the solution behavior of custom synthesized polymeric surfactants and additives.

[A method of perfluorinated organic compounds in drinking water determinated by HPLC-MS/MS]

OBJECTIVE

To establish a method of perfluorinated organic compounds (POCs) in drinking water determinated by HPLC-MS/MS.

METHODS

The contents of selected POCs (i. e., perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA) and perfluorodecanoate (PFDA)) in water samples were extracted by the C18 solid-phase extraction (SPE). The extraction samples were then identified and quantitated by high performance liquid chromatography-negative electrospray mass spectrometry (HPLC-ESI-MS/MS).

RESULTS

Linear calibration curves were obtained at the concentration ranges from 50 pg/ml to 1000 pg/ml (the correlation coefficients were above 0.99). The average recoveries for PFOA, PFOS and PFDA spiked in water ranged from 65 to 111% and their relative standard were between 3.6% and 14.6%. The limit of quantification (LOQ) of the method was 8 pg/g.

CONCLUSION

The method for determination of POCs in drinking water could be simple, sensitive and accurate.

Long-chain n-6 polyunsaturated fatty acids in breast milk decrease the risk of HIV transmission through breastfeeding

BACKGROUND

Breastfeeding accounts for a sizable proportion of infant HIV infections. Some fatty acids (FAs) are potent immunomodulators with virucidal activity, and their primary source in breastfed children is breast milk.

OBJECTIVES

The aims of the study were to examine whether the percentage weight concentration of FAs in breast milk was associated with the risk of mother-to-child transmission (MTCT) of HIV by breastfeeding and with shedding of cell-free virus (CFV) or cell-associated virus (CAV) in breast milk.

DESIGN

We conducted a case-control study nested within a cohort of HIV-infected Tanzanian women and children. We matched 59 incident breastfeeding MTCT cases to 59 nontransmitting controls based on the child's age at sample collection. We quantified FAs, CFV, and CAV in a breast milk sample collected before the infant's first positive HIV test.

RESULTS

After adjustment for indicators of maternal HIV disease stage, the risk of MTCT was inversely related to 11c,14c-eicosadienoic acid [odds ratio (OR) for quartile 4 compared with quartile 1: 0.21; P for trend = 0.04], arachidonic acid (OR: 0.21; P for trend = 0.03), and dihomo-gamma-linolenic acid (OR: 0.24; P for trend = 0.03); the latter 2 were also linearly, inversely related to virus shedding in breast milk. Lauric acid and pentadecanoic acid were associated with increased MTCT, whereas trans FAs were related to higher CAV and CFV.

CONCLUSION

Increasing concentrations of long-chain n-6 polyunsaturated FAs in breast milk might reduce the risk of MTCT.

Production of Polyhydroxyalkanoates with High 3-Hydroxydodecanoate Monomer Content byfadBandfadAKnockout Mutant ofPseudomonas putidaKT2442

Pseudomonas putida KT2442 produces medium-chain-length (MCL) polyhydroxyalkanoates (PHA) consisting of 3-hydroxyhexanoate (HHx), 3-hydroxyoctanoate (HO), 3-hydroxydecanoate (HD), and 3-hydroxydodecanoate (HDD) from a wide-range of carbon sources. In this study, fadA and fadB genes encoding 3-ketoacyl-CoA thiolase and 3-hydroxyacyl-CoA dehydrogenase in P. putida KT2442 were knocked out to weaken the beta-oxidation pathway. Two-step culture was proven as the optimal method for PHA production in the mutant termed P. putida KTOY06. In a shake-flask culture, when dodecanoate was used as a carbon source, P. putida KTOY06 accumulated 84 wt % PHA, much higher than 50 wt % PHA in its wild type KT2442. The PHA monomer composition was completely different: the HDD fraction in PHA produced by KTOY06 was 41 mol %, much higher compared with 7.5 mol % only in KT2442. The fermentor-scale culture indicated the HDD fraction in PHA decreased during the culture time from 35 to 25 mol % in a one-step fermentation process or from 75 to 49 mol % in a two-step fermentation process. It is for the first time that PHA with a dominant HDD fraction was produced. Thermal and mechanical properties assays indicated that this new type PHA with a high HDD fraction had higher crystallinity and tensile strength than PHA with a low HDD fraction did, demonstrating an improved application property.

Milk in the island of Chole [Tanzania] is high in lauric, myristic, arachidonic and docosahexaenoic acids, and low in linoleic acid reconstructed diet of infants born to our ancestors living in tropical coastal regions

BACKGROUND

We need information on the diet on which our genes evolved.

OBJECTIVE

We studied the milk fatty acid [FA] composition of mothers living in the island of Chole [Tanzania, Indian Ocean]. These mothers have high intakes of boiled marine fish and coconut, and consume plenty amount of fruits and vegetables.

DESIGN

The outcome was compared with three fish-eating tribes living along Tanzanian freshwater lakes [Kerewe, Nyakius, Nyiramba], four tribes living in the Tanzanian inland [Hadzabe, Maasai, Sonjo, Iraqw] and our milk FA database.

RESULTS

Milk from Chole contained high levels of 12:0 [20.17 g%], 14:0 [21.19], 12:0/14:0 ratio [0.92 g/g], arachidonic acid [AA, 0.50 g%] and docosahexaenoic acid [DHA, 0.73], but low levels of linoleic acid [LA, 4.23]. The combination of a high medium chain fatty acid [MCFA; <C16] content and 12:0/14:0 ratio derives notably from coconut consumption, as opposed to a carbohydrate rich diet, while non-existent use of vegetable oils explains low LA. Milk AA/DHA ratios of the four fish-eating groups were related to the AA/DHA ratios of the available fish. Chole MCFA and LA did not fulfill Western recommendations for formulae, while AA and DHA were well above minimum levels.

CONCLUSIONS

The Chole milk FA composition is likely to reflect the dietary FA composition of babies born to our ancient ancestors living in East-African coastal regions. The poor compliance with present recommendations raises doubts on the validity of recommendations that are based on milk from Western mothers consuming diets that confer high risk of diseases typical for affluent countries.

Whey-derived free fatty acids suppress the germination of Candida albicans in vitro

Bovine whey from the cheese-making industry contains several bioactive factors that promote health and prevent disease. Although many efforts have been made over the years to show that immunoglobulins, lactoperoxidase, lactoferrin, lysosyme and small peptides present in whey have antimicrobial activities against several pathogenic microorganisms, such activities have not been investigated so far for the lipid fraction of whey. Here, we have used an in vitro assay-based fractionation procedure to show that free fatty acids derived from whey cream specifically inhibit the germination of Candida albicans, a morphologic change associated with pathogenicity. Further fractionation by HPLC demonstrated that this activity can be mainly attributed to lauric acid, myristoleic acid, linoleic acid and arachidonic acid.

[Analysis of the impurity of bacterium source of standard endotoxin by gas chromatography/mass spectrometry]

To analyse the impurity of bacterium source of standard endotoxin, 3-hydroxy fatty acid species in different endotoxin standards was determined by gas chromatography/mass spectrometry (GC/MS) using N, O-bis (trimethylsilyl) trifluoroacetamide as the silanizing reagent. GC/MS analysis was performed using a gas chromatograph equipped with a 60 m x 0.25 mm i. d. DB-5 fused silica capillary column and an injector at 250 degrees C. Helium was used as the carrier gas under a constant pressure of 206 kPa. The oven was programmed at a rate of 5 degrees C /min from 90 degrees C (held for 5 min) to 280 degrees C (held for 5 min). The sample size was 1 microL. The transfer line was kept at 280 degrees C. The quadrupole mass spectrometer was operated in electron impact (EI) ionization mode, and the temperature of the source was kept at 250 degrees C. The kind of 3-hydroxy fatty acids in 9 000 EU/tube national standard endotoxin, 20 EU/tube working standard endotoxin, Escherichia coli, Pseudomonas aeruginosa and deionized water were determined to study the purity of bacterium source of the standard endotoxin. It was shown that 9 000 EU/tube endotoxin standard and Escherichia coli only contained 3-hydroxytetradecanoic acid. There was 3-hydroxydodecanoic acid in 20 EU/tube working standard endotoxin, which indicated the presence of impurity of bacterium source.

A degradation study of PLLA containing lauric acid

Addition of lauric acid to poly (L-lactide) (PLLA) has resulted in a new family of enhanced degradation biomaterials. Presented is PLLA4.5 (PLLA containing 4.5 wt% lauric acid), the fastest degrading of the family. Degradation was studied via mass changes, gel-permeation chromatography, wide- and small-angle X-ray scattering (WAXS and SAXS), simultaneous SAXS and tensile testing, and visual observation. The undegraded PLLA4.5 deformed by crazing, recognisable from the characteristic shape of the SAXS pattern. As water up-take and degradation proceeded, samples crystallised, decreasing the SAXS long period, until by 4 days the deformation mechanism had become that of crystal-mediated deformation. This resulted in a 'peanut-lemon'-shaped SAXS pattern, interpreted in terms of cavitation and fibrillated shear. Further degradation up to 12 days resulted in the same deformation mechanism at different sample displacements, with samples failing earlier during tensile testing until a ductile-brittle transition occurred. At 30-40 days water up-take and mass-loss increased significantly and global whitening of samples occurred, while the crystallinity and long period stabilised. Complete degradation had not occurred by the end of the study at 73 days. Through an understanding of how the changes in morphology during degradation affect the micromechanisms of deformation, it may be possible to design microstructures to give a tailored evolution of mechanical response in the body.

Analysis of lipolysis in adipocytes using a fluorescent fatty acid derivative

For facilitation of the experimental analysis of the mechanism and regulation of mobilization of fatty acids from adipose triacylglycerol (TAG) stores, which also represents important targets for pharmacological intervention with the pathogenesis of diabetes and obesity, we developed a convenient and reliable non-radioactive cell-based assay. Isolated rat adipocytes are incubated with the fluorescent fatty acid derivative, 12-((7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)dodecanoic acid (NBD-FA), in the presence of insulin. The resulting NBD-FA-labeled TAG is efficiently cleaved by hormone-sensitive lipase (HSL) in vitro. After removal of insulin and excess of free NBD-FA, lipolysis is initiated by addition of isoproterenol and/or adenosine deaminase. The amount of NBD-FA generated in total or released into the incubation medium in the presence of modulatory hormones or compounds is then monitored by thin layer chromatography and fluorescence imaging. Release of NBD-FA, glycerol and [3H]oleic acid from TAG follows similar kinetics and concentration dependence in response to various lipolytic and anti-lipolytic stimuli as well as inhibitors of HSL. Release of NBD-FA from adipocytes correlates well to translocation of HSL from the cytosol to TAG droplets. In addition, we found that a cell-free system consisting of NBD-FA-labeled TAG droplets with endogenous associated HSL closely reflects the lipolytic state of the adipocytes used for its preparation. In conclusion, release of NBD-FA from TAG in vivo and in vitro can be used as accurate index for (regulation of) lipolysis in primary and cultured adipocytes.

The interaction of azacrown ether with fatty acid in nonpolar solvents and at the organic–aqueous interface

In the paper, we show that lipophilic azacrown ether (22DD) in solvents of low to intermediate polarity forms the complexes with fatty acids, like lauric or palmitic acid. Due to the weak acid-base properties of the azacrown ether-fatty acid system, no proton transfer between the two molecules was observed, as shown by IR and 1H NMR studies. The Job plot exhibits double maximum, suggesting the coexistence of two 22DD-fatty acid complexes, of 1:1 and 1:2 stoichiometry, respectively. Their stability constants were calculated by taking into account the dimerization of fatty acid in toluene. The diffusion coefficients for the free molecules and their complexes were measured with diffusion-ordered spectroscopy (DOSY) NMR in order to prove the close spatial proximity of the molecules. Interfacial tension measurements at the water-toluene interface showed that due to the presence of two decyl chains, 22DD adsorbs at the interface much stronger than dodecanoic (lauric) acid does. The shape of the adsorption isotherm for the mixture of 22DD and lauric acid suggests that the two molecules also interact at the interface in a similar manner as in the bulk of low to intermediate polarity solvents. As a result of the affinity of the fatty acid to strongly surface-active azacrown ether, the interface might be enriched with fatty acid molecules, which without 22DD shows little adsorption at the liquid-liquid interface.

Effect of dose of calcium salts of conjugated linoleic acid (CLA) on percentage and fatty acid content of milk fat in midlactation holstein cows

Increasing conjugated linoleic acid (CLA) content of milk fat from lactating dairy cattle has become a research interest due to the possible health benefits afforded humans consuming CLA. Dietary supplementation of CLA to lactating dairy cows is one potential method by which CLA content of milk and dairy products may be enhanced. Feeding CLA in calcium salt form could potentially deliver CLA to the lower digestive tract through prevention of biohydrogenation by rumen microbes. Milk fat depression (MFD) occurs when cows receive CLA-60, a commercially available CLA source containing numerous CLA isomers, abomasally. Our objectives were to determine the quantity of CLA as calcium salts required to elicit maximal MFD and to evaluate the effects of CLA supplementation on fatty acid composition of milk fat. Five Holstein cows at approximately 93 DIM were utilized in a 5 x 5 balanced Latin square crossover design. Periods were 14-d in length with a 5-d treatment phase and 9-d rest phase. Treatments were 5-d supplementation of 0, 12.5, 25, 50, and 100 g of CLA-60 in calcium salt form. Milk samples were collected on d 5 of CLA supplementation and analyzed for composition and fatty acid profile. Regression analysis of milk fat data suggested that MFD was not maximized over the dose levels investigated, despite delivery of 34.5 g of trans-10, cis-12 CLA in the 100-g dose of CLA. Supplementation with 50 and 100 g of CLA per day resulted in a reduction of milk fat percent of 29 and 34%, respectively. Trend analysis indicated a linear decrease in the milk fat content of caprylic, capric, and lauric acids as the dose of CLA increased. Milk fat content of cis-9, trans-11, and trans-10, cis-12 CLA increased at an increasing rate as dose increased.

Identification of omega hydroxy fatty acids in biological samples as their pentafluoropropyl derivatives by gas chromatography/mass spectrometry with positive and negative ion detection

A simple one-step procedure for derivatization of the omega hydroxy fatty acids 20-hydroxyeicotetraeonic acid and 12-hydroxylauric acid is presented. The procedure involves acylation of the terminal hydroxy group and esterification of the carboxylic acid with a mixture of pentafluoropropionic anhydride and pentafluoropropanol. Positive and negative ion spectra for the derivatives are presented. The procedure was used to demonstrate conversion of arachidonic acid to 20-hydroxyeicosatetraeonic acid and lauric acid to 12-hydroxylauric acid in kidney microsomal incubations. The reaction appears to be specific, since derivatives of subterminal fatty acids (secondary alcohols) could not be detected.

Effects of aliphatic dioic acids and glycerol-1,2,3-tris(dodecanedioate) on D-glucose-stimulated insulin release in rat pancreatic islets

Aliphatic dioic acids have been proposed as alternative nutrients in selected clinical situations. In this study, their possible insulinotropic action was investigated in isolated rat pancreatic islets prepared from fed rats. Azelaic acid, sebacic acid and tridecanedioic acids, when tested at a 10.0 mm concentration, were found to augment insulin release evoked by D-glucose (7.0 mm) in the pancreatic islets. Likewise, glycerol-1,2,3-tris(dodecanoedioate), when used at concentrations close to 1.0 mm, increased the secretory response to the hexose. It is speculated that these findings may extend to insulin-producing cells, the knowledge that aliphatic dioic acids or their esters may act as energy substrates, e.g. in parenteral nutrition.

Role of Yersinia intermedia and Pseudomonas putida in the development of a fruity off-flavour in pasteurized milk

Analysis by gas chromatography-mass spectrometry of pasteurized milk with a fruity (pineapple like) off odour and a sour, rancid and soapy taste indicated the presence of concentrations at microg/ml levels of ethyl butanoate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, octanoic acid, decanoic acid and dodecanoic acid. The off-odour and taste were attributed to the presence of these compounds in the milk. Microbiological examination confirmed that the milk was also contaminated with a series of psychrotrophic bacteria including Yersinia intermedia, Pseudomonas putida and Rahnella aquatilis. Growth of isolates of these bacteria in UHT milk at 23 degrees C for 7 d showed that Yer. intermedia produced significant quantities of the C4-C12 alkanoic acids; Ps. putida produced only small quantities of these acids and Rah. aquatilis produced none. In addition, Yer. intermedia and Ps. putida also produced small but significant quantities of the corresponding ethyl esters. In milk inoculated with both Yer. intermedia and Ps. patida, the quantity of ethyl esters produced was greater than that found in cultures containing only one of the isolates. These studies indicated that Yer. intermedia was the principal source of the alkanoic acids in the tainted milk and that the major producer of the corresponding ethyl esters was Ps. patida. This is the first report that Yer. intermedia and Ps. putida can cause an off-odour or taste in dairy products.

Synthesis of 9,12-dioxo-10(Z)-dodecenoic acid, a new fatty acid metabolite derived from 9-hydroperoxy-10,12-octadecadienoic acid in lentil seed (Lens culinaris Medik.)

The previously unknown linoleic acid peroxidation product 9,12-dioxo-10(Z)-decenoic acid (Z5) was detected in lentil seed flour (Lens culinaris Medik.) by electron impact mass spectrometry (EI-MS) after derivatization with pentafluorobenzyl-hydroxylamine-hydrochloride, methylation of acidic groups with diazomethane, and protection of hydroxylic groups with N-methyl-N-trimethylsilyl-trifluoroacetamide. The structure of the natural product was confirmed by synthesis of Z5, 9,12-dioxo-l0(E)-decenoic acid, and derivatives. EI-MS, nuclear magnetic resonance and gas chromatographic data of these compounds and synthetic intermediates are discussed.

Characterization of a biosurfactant, mannosylerythritol lipid produced from Candida sp. SY16

One yeast strain, SY16, was selected as a potential producer of a biosurfactant, and identified as a Candida species. A biosurfactant produced from Candida sp. SY16 was purified and confirmed to be a glycolipid. This glycolipid-type biosurfactant lowered the surface tension of water to 29 dyne/cm at critical micelle concentration of 10 mg/l (1.5 x 10(-5) M), and the minimum interfacial tension was 0.1 dyne/cm against kerosene. Thin-layer and high-pressure liquid chromatography studies demonstrated that the glycolipid contained mannosylerythritol as a hydrophilic moiety. The hydrophilic sugar moiety of the biosurfactant was determined to be beta-D-mannopyranosyl-(1-->4)-O-meso-erythritol by nuclear magnetic resonance (NMR) and fast atom bombardment mass-spectroscopy analyses. The hydrophobic moiety, fatty acids, of the biosurfactant was determined to be hexanoic, dodecanoic, tetradecanoic, and tetradecenoic acid by gas chromatography-mass spectroscopy. The structure of the native biosurfactant was determined to be 6-O-acetyl-2,3-di-O-alkanoyl-beta-D-mannopyranosyl-(1-->4)-O-meso- erythritol by NMR analyses. We newly determined that an acetyl group was linked to the C-6 position of the D-mannose unit in the hydrophilic sugar moiety.

Lipid composition of hepatocyte plasma membranes from geese overfed with corn

Twelve-week-old Landes male geese were overfed with corn for 21 d in order to induce liver steatosis (fatty liver). Lipid composition of hepatocyte plasma membranes from fatty livers was compared to that of lean livers obtained from geese fed a normal diet. The ratio cholesterol/phospholipids was higher in fatty hepatocyte plasma membranes (0.63 vs. 0.47), whereas the phospholipid/protein ratio was less than half. Overfeeding induced changes in fatty acid composition of hepatocyte plasma membranes, including a greater than twofold increase in the percentage of oleic acid (29.7 vs. 13.8%) and a somewhat lesser increase in lauric, palmitic, and palmitoleic acid contents of plasma membrane lipids of fatty livers. A concomitant reduction in the proportion of stearic acid (18.4 vs. 25.1%) was also observed. In fatty livers, the increased ratio of saturated to polyunsaturated fatty acids (PUFA) (1.5 vs. 1.0) was related to a significant decrease in PUFA content. Among all the PUFA, only the eicosatrienoic acid (20:3n-9) percentage was increased by liver steatosis. Overfeeding with corn appeared to induce competition between de novo synthesized and dietary fatty acids incorporated in hepatocyte plasma membranes. This resulted in an accumulation of de novo synthesized monounsaturated and derived fatty acids in plasma membranes from overfed birds. A defect in the incorporation of linoleic acid and linoleic- and linolenic-derived PUFA was observed despite the high proportion of these essential fatty acids in the diet. It was concluded that in overfed palmipeds, de novo hepatic lipogenesis prevails over dietary lipid intake to modulate lipid composition of the fatty liver plasma membrane.

Outer membrane changes in a toluene-sensitive mutant of toluene-tolerant Pseudomonas putida IH-2000

We isolated a toluene-sensitive mutant, named mutant No. 32, which showed unchanged antibiotic resistance levels, from toluene-tolerant Pseudomonas putida IH-2000 by transposon mutagenesis with Tn5. The gene disrupted by insertion of Tn5 was identified as cyoC, which is one of the subunits of cytochrome o. The membrane protein, phospholipid, and lipopolysaccharide (LPS) of IH-2000 and that of mutant No. 32 were examined and compared. Some of the outer membrane proteins showed a decrease in mutant No. 32. The fatty acid components of LPS were found to be dodecanoic acid, 2-hydroxydodecanoic acid, 3-hydroxydodecanoic acid, and 3-hydroxydecanoic acid in both IH-2000 and No. 32; however, the relative proportions of these components differed in the two strains. Furthermore, cell surface hydrophobicity was increased in No. 32. These data suggest that mutation of cyoC caused the decrease in outer membrane proteins and the changing fatty acid composition of LPS. These changes in the outer membrane would cause an increase in cell surface hydrophobicity, and mutant No. 32 is considered to be sensitive to toluene.

Saccharomyces cerevisiae cell fatty acid composition and release during fermentation without aeration and in absence of exogenous lipids

Medium-chain fatty-acids (MCFA) are among the main aroma compounds of fermented beverages. High concentrations of MCFA have been found in sluggish and stuck fermentations. It has been suggested that they arrest cell growth, as they may be toxic, but the causes of sluggish and stuck fermentations are still unclear. The aim of this work was to see whether the production of MCFA is related to fatty acid synthesis in the absence of exogenous lipids and aeration, and whether their increase can be regarded as a consequence, instead of the cause, of sluggish and stuck fermentations. Two possibilities were considered: (i) MCFA are produced to replace unsaturated fatty acids (UFA) for cell membrane fluidity when the lack of oxygen makes desaturation of saturated fatty acids (SFA) impossible; or (ii) MCFA are produced following the release of medium-chain acyl-CoA from the fatty acid synthetase complex (FAS) due to the accumulation of SFA, and their hydrolysis to recycle CoA-SH. In the first hypothesis, MCFA should be active in cell metabolism and be found in cell structures; in the second, MCFA should be a discard and prevalently found outside the cell. We carried out a Saccharomyces cerevisiae fermentation experiment in a synthetic, lipid-free medium without aeration. We measured the fatty acid composition of yeast cells and the amounts of MCFA and their ethyl esters in the medium throughout the fermentation. Cell growth and the oxygen content of the medium were also monitored. We found that MCFA are not immobilized in cell structures, but mainly released into the medium. Cell growth is arrested because fatty acid biosynthesis is prevented by the lack of oxygen. The higher MCFA concentrations found in sluggish and stuck fermentations can be thus regarded as an effect, and not the cause, of this arrest. Some suggestions for the prevention of these events are proposed.

Quantitative determination of polysorbate 20 in nasal pharmaceutical preparations by high-performance liquid chromatography

A specific reverse-phase HPLC method has been developed for the quantitative determination of polysorbate 20 in various compositions of nasal solutions. This method is based on the acidic hydrolysis of the sorbitan laurate ester followed by the HPLC determination of the free lauric acid. Using this method, polysorbate 20 can effectively be separated and quantitatively determined in matrices containing a wide variety of preservatives, surfactants, and viscosity agents. Sample preparation involves a one-step hydrolysis with sulfuric acid and then a dilution with acetonitrile, prior to injection. The sample is analyzed on a 5-microm octadecylsilane reverse-phase column with a mobile phase of acetonitrile: 0.025 M aqueous di-Sodium hydrogen phosphate, pH = 2.8 (75:25). The column effluent is monitored by UV detection at 210 nm. The validity of the method has been verified with specificity, linearity, recovery, method- and system precisions data. The method is linear for polysorbate 20 from 2.5 to 125 mg ml(-1) range. The limit of detection and limit of quantitation are 0.41 and 0.61 mg ml(-1), respectively.

Mutation of the htrB gene in a virulent Salmonella typhimurium strain by intergeneric transduction: strain construction and phenotypic characterization

The htrB gene product of Haemophilus influenzae contributes to the toxicity of the lipooligosaccharide. The htrB gene encodes a 2-keto-3-deoxyoctulosonic acid-dependent acyltransferase which is responsible for myristic acid substitutions at the hydroxy moiety of lipid A beta-hydroxymyristic acid. Mass spectroscopic analysis has demonstrated that lipid A from an H. influenzae htrB mutant is predominantly tetraacyl and similar in structure to lipid IV(A), which has been shown to be nontoxic in animal models. We sought to construct a Salmonella typhimurium htrB mutant in order to investigate the contribution of htrB to virulence in a well-defined murine typhoid model of animal pathogenesis. To this end, an r- m+ galE mutS recD strain of S. typhimurium was constructed (MGS-7) and used in inter- and intrastrain transduction experiments with both coliphage P1 and Salmonella phage P22. The Escherichia coli htrB gene containing a mini-Tn10 insertion was transduced from E. coli MLK217 into S. typhimurium MGS-7 via phage P1 and subsequently via phage P22 into the virulent Salmonella strain SL1344. All S. typhimurium transductants showed phenotypes similar to those described for the E. coli htrB mutant. Mass spectrometric analysis of the crude lipid A fraction from the lipopolysaccharide of the S. typhimurium htrB mutant strain showed that for the dominant hexaacyl form, a lauric acid moiety was lost at one position on the lipid A and a palmitic acid moiety was added at another position; for the less abundant heptaacyl species, the lauric acid was replaced with palmitoleic acid.

Determination of the route of medium-chain and long-chain fatty acid absorption by direct measurement in the rat

BACKGROUND

Medium-chain triglycerides are used for the treatment of malabsorptive states. We measured directly the absorption of medium- and long-chain fatty acids via the mesenteric lymphatics and portal vein in normal animals. These results may be useful in guiding therapy for short-bowel syndrome.

METHODS

Under anesthesia, male Lewis rats (n = 6) underwent placement of jugular and portal venous lines, mesenteric lymphatic duct cannula, and a duodenal tube. After recovery, a 0.3% lauric acid (C12:0) and 0.37% palmitic acid (C16:0) solution solublized with 3.25 mmol/L lecithin and 23.75 mmol/L taurocholic acid in phosphate-buffered saline was infused at a rate of 3 mL/h via the duodenal tube. After stabilization of lymphatic flow (6 hours), a pulse of radiolabeled lauric and palmitic acid was given via the duodenal tube; absorption was measured by collection of lymphatic fluid and sampling of the portal and jugular venous blood for 4 hours.

RESULTS

The amount of acid recovered in the lymphatics was 51% +/- 6% (mean +/- SD) for lauric and 59% +/- 6% for palmitic. For both fatty acids, < 1% in total was recovered from the portal vein during the 4-hour postbolus period; thereafter, levels in the blood were constant and very low. At necropsy, the majority of the remaining label was found in the intestine.

CONCLUSIONS

These results show no evidence for the preferential absorption of medium-chain fatty acids directly via the portal vein in this model. We suggest that further studies be done to measure directly portal vein absorption of the medium-chain fatty acids.