Influence of C18 long chain fatty acids on butyrate degradation by a mixed culture

Butyrate degradation in the presence of C₁₈ long chain fatty acids (LCFAs) was examined under anaerobic conditions at 21 °C. Butyrate degradation rates were a function of linoleic acid (LA) and oleic acid (OA) concentration but independent of the amount of stearic acid (SA) added. Within 2–4 h, butyrate reached undetectable levels in the control cultures. However, in cultures fed with LA, butyrate was removed within between 12 and 25 h and within 2–12 h for cultures inoculated with OA or SA. Propionate was detected in cultures fed with 50 mg dm^?3 LA and in cultures inoculated with OA and SA. LA exerted a greater inhibitory effect on butyrate‐degrading organisms than OA and SA with longer removal times observed in cultures fed with LA. The propionate and acetate removal times and quantity produced were not related to the type and concentration of LCFA. Copyright © 2004 Society of Chemical Industry     

Glucose fermentation in the presence of linoleic,oleic and stearic acids by a mixed culture

Long Chain Fatty Acid (LCFA) mixtures containing linoleic, oleic and stearic acids plus carbohydrates are found in a variety of effluents arising from fried food manufacture and milk processing. Accumulation of Volatile Fatty acids (VFAs) due to the presence of LCFAs may impair the operation of an anaerobic system treating effluents containing a mixture of triglycerides and carbohydrates. In this study, the effects of linoleic (C18:2), oleic (C18:1), and stearic (C18:0) acids on glucose fermentation were investigated at 21 °C using a culture acclimated to glucose. In cultures receiving ≥300 mg dm^?3 LCFAs, residual amounts of glucose remained after approximately 8 h and none was detected after 24 h. Acetate degradation was inhibited in the presence of 300 or more mg dm^?3 linoleic acid (LA), oleic acid (OA), or stearic acid (SA) with more acetate accumulation observed in cultures receiving LA. In comparison to the controls, similar amounts of propionate accumulation were observed in cultures receiving ≤100 mg dm^?3 of each LCFA. However, in cultures receiving ≥300 mg dm^?3 LCFAs, more propionate accumulated with complete removal observed within 20 days for only those cultures receiving oleic or stearic acids. Butyrate accumulation was observed only in cultures receiving ≥300 mg dm^?3 LA and none was detected after 10 days of incubation. Copyright © 2004 Society of Chemical Industry     

Δ6 Desaturase mRNA Abundance in HepG2 Cells Is Suppressed by Unsaturated Fatty Acids

The effect of unsaturated fatty acids on the abundance of Δ6 desaturase (D6D) mRNA and the fatty acid composition of HepG2 cell membranes was examined. Supplementation of HepG2 cells with oleic acid (18:1n-9, OA), linoleic acid (18:2n-6, LA), α-linolenic acid (18:3n-3, ALA), arachidonic acid (20:4n-6, AA) or eicosapentaenoic acid (20:5n-3, EPA) reduced D6D mRNA abundance by 39 ± 6.6, 40 ± 2.2, 31 ± 5.2, 55 ± 4.8, and 52 ± 5.0%, respectively, compared with control cells. Despite the reduction in D6D mRNA abundance, the level of D6D conversion products (20:3n-9, EPA and AA) in OA, ALA and LA supplemented cells, respectively, was elevated above that in control cells. Our results suggest that although unsaturated fatty acids decrease the abundance of D6D mRNA by as much as 50%, the conversion of polyunsaturated fatty acids and accumulation of long chain polyunsaturated fatty acids (LCPUFA) in HepG2 cell phospholipids continues to occur.     

The production of propionic acid from sugars by fermentation through lactic acid as an intermediate

As an alternative to propionic acid production from sugars by species of propionibacteria, propionic acid may be produced from sugars through lactate as an intermediate. Propionibacteria are actually able to utilize lactate as a substrate much more rapidly than glucose. In this study, Lactobacillus xylosus and Propionibacterium shermanii were utilized to convert glucose and xylose to propionate through lactate as an intermediate. Pure culture batch studies were carried out to obtain fermentation parameters for the two cultures. The pure cultures were then combined in a mixed culture series arrangement designed to prevent nutrient limitation. Finally, propionic acid production from lactate was demonstrated in a cross-linked immobilized cell reactor using lactate added to the medium and produced by L. xylosus in a continuous stirred tank reactor. Productivities of 14 g dm^?3 h^?1 at a 9 min residence time (2·1 g dm^?3 propionate) and 2 g dm^?3 h^?1 at a 9·9 h residence time (19·7 g dm^?3 propionate) were obtained without pH control.     

Investigation of the effects of fatty acids on the compressive strength of the concrete and the grindability of the cement

In cement industry, a great energy consumption has been observed during grinding of clinker. To reduce this consumption, some waste products have been used as grinding aids.In this investigation, the effects of sunflower oil (SO), oleic acid (OA), stearic acid (SA), myristic acid (MA) and lauric acid (LA) on the fineness and strength of the cement have been examined. These aids were added into clinker in certain ratios based on the cement clinker weight and the grinding has been done for a definite time at the same condition.All of the fatty acids used increased the fineness as compared with the cement without the grinding additives. SO and OA decreased the strength significantly, LA decreased it to a lesser extent and SA increased it definitely according to the common cement. But MA did not alter the strength of the cement as much as SA. In addition, the covering of the balls influences the grinding of cement clinker unfavourably.     

Interference effects from coexisting fatty acids on elaidic acid separation by fractionating crystallization: A model study

A multi‐stage temperature‐programmed fractionating crystallization process was carried out to examine the effects of the presence of stearic acid (SA), oleic acid (OA), and linoleic acid (LA) on the separation of elaidic acid (EA). The results showed that the efficiency of fractionating crystallization of EA depended largely on the crystallization temperature, initial concentration of EA and presence of SA. The content of SA plays very important role for the fractionating performance. It was a characteristic observation that only when SA <2%, substantial crystallization of EA (>50% in stepwise crystal fractions) were obtained regardless of the initial concentration of SA. In general, SA induced crystallization of EA in earlier stage but delayed further crystallization of EA in later stage; the crystallization of EA was independent from co‐existing OA and LA. After reduction of EA content in solution to certain extent (7–10%, at ?20°C), further reduction of EA content requires much lower crystallization temperatures (trans‐fatty acids (TFA) from partially hydrogenated soybean oil (PHSO) is of high commercial interest. One of the strategies is to selectively release TFAs as free fatty acids from PHSO enzymatically. However, all commercially available enzymes are far away from qualified to selectively release TFAs, where there are always substantial non‐trans FAs hydrolyzed simultaneously. Therefore, developing post‐processing technology is requisite in order to recover those non‐trans fatty acids. Thus, this model system was designed based on FA composition characteristic of PHSO, which aimed to acquire some basic data and experience that lack in available literatures, so as to serve designing efficient practical process for removing trans‐fatty acid moieties from PHSO. The results from this work may be of general value to achieve a better understanding of fractionating crystallization behaviors of different FAs, relationship with individual molecular feature and property, and their interference effects, which might contribute to the design of practically feasible protocol to remove TFAs from PHSO and recover non‐trans FAs at the same time.     

Staged and non-staged anaerobic filters: Microbial activity segregation,hydrodynamic behaviour and performance

This work describes a comparative study of staged and non-staged anaerobic filters for treating a synthetic dairy waste under similar operating conditions. The effect of increasing the substrate concentration from 3 to 12 g COD dm⁻³ at a constant hydraulic residence time (HRT) of 2 days was evaluated with respect to overall reactor performance, biogas production, volatile fatty acids profiles along the height, methanogenic and acidogenic activity distribution, and hydrodynamic behaviour. The potential maximum specific methanogenic activity against acetate, hydrogen, propionate and butyrate and the lactose specific activity were determined for sludge sampled from three different points in each reactor, under two operating conditions (influent COD of 3 and 9 g COD dm⁻³). Although all trophic groups involved in the anaerobic process were found throughout the reactors, it was possible to identify different specific sludges at different heights in both reactors. Performances of the two configurations were very similar under the operating conditions tested and the plug flow behaviour of the staged reactor was clearly reduced when the influent concentration increased from 3 to 9 g COD dm⁻³. © 1998 Society of Chemical Industry     

Fatty acid profiles in tissues of mice fed conjugated linoleic acid

The incorporation of vaccenic acid (VA, 0.5 and 1.2%), conjugated linoleic acid (CLA, mixture of primarily c9,t11‐ and t10,c12‐CLA, 1.2%), linoleic acid (LA, 1.2%) and oleic acid (OA, 1.2%) into different tissues of mice was examined. The effects on the fatty acid composition of triacylglycerols (TAG) and phospholipids (PL) in kidney, spleen, liver and adipose tissue were investigated. VA and CLA (c9,t11‐ and t10,c12‐CLA) were primarily found in TAG, especially in kidney and adipose tissue, respectively. Conversion of VA to c9,t11‐CLA was indicated by our results, as both fatty acids were incorporated into all the analyzed tissues when a diet containing VA but not c9,t11‐CLA was fed. Most of the observed effects on the fatty acid profiles were seen in the CLA group, whereas only minor effects were observed in the VA groups compared with the OA group. Thus, CLA increased n‐3 polyunsaturated fatty acids (PUFA) in PL from kidney and spleen and lowered the ratio of n‐6/n‐3 PUFA in these tissues. Furthermore, CLA increased C₂₂ PUFA in the PL fraction of kidney, spleen and liver, but reduced the level of arachidonic acid in PL of liver and spleen and lowered the Δ⁹‐desaturation indexes in all analyzed tissue TAG.     

Effect of dietary fat on the lipid composition and utilization of short-chain fatty acids by rat colonocytes

The objective of the present studies was to examine the effect of dietary fat on the lipid composition of rat colonocytes and their utilization of short-chain fatty acids (SCFA). Rats were fed 14% beef fat, fish oil or safflower oil plus 2% corn oil in a semi-synthetic base diet for 4 wk. Colonocytes were isolated and their lipid composition was examined. Feeding beef fat and fish oil resulted in an increase in monounsaturated fatty acids and a reduction in ω-6 fatty acids. Feeding fish oil resulted in an enrichment with ω-3 fatty acids. These was no dietary influence on the amount of either cholesterol or phospholipids of colonocytes. Fish oil feeding resulted in significant increase in colonocyte free fatty acids (FFA) as compared to other diets. Dietary fat was found to have no effect on SCFA utilization by colonocytes. Colonocytes were found to utilize SCFA in the order of butyrate ≥acetate ≥propionate. The presence of acetate and propionate in the medium had no effect on the rate of butyrate utilization.     

Thioglycolate-elicited rat macrophages exhibit alterations in incroporation and oxidation of fatty acids

Incorporation and oxidation of fatty acids (FA) were investigated in resident and thioglycolate-clicited (TG-elicited) rat macrophages (Mϕ). Both cell types presented a time-dependent incorporation of [¹⁴C]-labeled palmitic acid (PA), oleic acid (OA), linoleic acid (LA), and arachidonic acid (AA) up to 6h. The total amount of [¹⁴C]-FA incorporated by resident Mϕ after 6 h was: AA>PA=LA>OA. TG-elicited cells presented a 50% reduction in the incorporation of LA, PA, and AA, whereas that of OA remained unchanged as compared to resident Mϕ. The FA were oxidized by resident Mϕ as follows: LA>OA>PA>AA. TG elicitation promoted a reduction of 42% in LA oxidation and a marked increase in AA oxidation (280%). The increased oxidation of AA in TG-elicited cells may account for the lower production of prostaglandins in Mϕ under these conditions. The full significance of these findings for Mϕ function, however, remains to be examined.     

Kinetic modelling of lactic acid production from whey by Lactobacillus casei (NRRL B‐441)

The biomass growth, lactic acid production and lactose utilisation kinetics of lactic acid production from whey by Lactobacillus casei was studied. Batch fermentation experiments were performed at controlled pH and temperature with six different initial whey lactose concentrations (9‐77 g dm^?3) in a 3 dm³ working volume bioreactor. Biomass growth was well described by the logistic equation with a product inhibition term. In addition, biomass and product inhibition effects were defined with corresponding power terms, which enabled adjustment of the model for low‐ and high‐substrate conditions. The Luedeking‐Piret equation defined the product formation kinetics. Substrate consumption was explained by production rate and maintenance requirements. A maximum productivity of 2.5 g dm^?3 h^?1 was attained with an initial lactose concentration of 35.5 g dm^?3. Copyright © 2006 Society of Chemical Industry     

Plasma clerance and hepatic utilization of stearic,myristic and linoleic acids introducedvia chylomicrons in rats

The primary objective of the present study was to compare the rates of plasma clearance and hepatic utilization of stearic (18∶0), myristic (14∶0) and linoleic (18∶2) acids, as introducedvia chylomicrons. Lymph chylomicrons were specifically labeledin vivo with [¹⁴C]stearic and (SA), [¹⁴C]myristic acid (MA), or [¹⁴C]linoleic acid (LA) by infusing donor rats intraduodenally with the labeled fatty acids in a lipid emulsion. Following intravenous injection of recipient rats with the labeled chylomicrons, the rates of plasma clearance and incorporation of the label in triglycerides (TG), phospholipids (PL) and other lipids in the liver were compared at 5, 15 and 30 min. [¹⁴C]SA was cleared at a slightly faster rate (t_1/2=7.0 min) than [¹⁴C]MA (t_1/2=8.1 min) and [¹⁴C]LA (t_1/2=8.0 min) (P<0.05). [¹⁴C]SA was accumulated in the liver at a significantly faster rate than [¹⁴C]MA and [¹⁴C]LA. At the peak (15 min) of hepatic uptake, 30.3% of [¹⁴C]SA, 26.2% of [¹⁴C]LA and 21.9% of [¹⁴C]MA were recovered in the liver. At 30 min, 33.5% of [¹⁴C]SA was taken up by the liver, whereas 27.8% of [¹⁴C]LA and only 15.2% of [¹⁴C]MA were removed. In the liver, the percentage of [¹⁴C]SA incorporated into PL steadily increased with time, whereas the percent-age incorporated into TG decreased. [¹⁴C]SA was preferentially incorporated into PL at all time intervals, as compared with [¹⁴C]MA and [¹⁴C]LA. At 30 min, 38.6% of [¹⁴C]SA was found in PL, and only 5.2% of [¹⁴C]MA and 12.0% of [¹⁴C]LA were present in PL. A large proportion of hepatic [¹⁴C]MA remained unesterified (free fatty acid) throughout the 30-min period, with a small proportion incorporated into PL and TG. Of the total liver¹⁴C radioactivity recovered at 30 min, 63.8% of [¹⁴C]MA, 48.8% of [¹⁴C]LA and 25.5% of [¹⁴C]SA were found unesterified. During 30 min, a significantly greater amount of [¹⁴C]MA (76.9%) was oxidized in both the liver and the peripheral tissue combined, compared with [¹⁴C]LA (64.7%) and [¹⁴C]SA (61.2%). A higher proportion of [¹⁴C]LA was incorporated into TG than into PL at all time intervals. No differences were noted in the relative distribution of¹⁴C in cholesterol and other lipids among the three fatty acids. Using labeled fatty acids incorporatedin vivo into chylomicrons, the present study demonstrated that SA, MA and LA are distinctly different in their metabolic behavior. During the initial 30 min after their entry into the blood, 92–95% of the fatty acids were cleared. During this early phase of metabolism, [¹⁴C]SA was preferentially utilized for liver PL synthesis, whereas [¹⁴C]LA was better incorporated into TG. [¹⁴C]MA was poorly incorporated into hepatic lipids, but was preferentially oxidized in the liver or utilized by the peripheral tissue.     

Optimization of volatile fatty acid compositions for hydrogen production by Rhodopseudomonas capsulata

The effects of volatile fatty acid (VFA) compositions on the cell growth, H₂ production rate and H₂ yield have been investigated using mathematical models. The results show that a modified logistic model indicates that the maximum cell growth of 0.03 h^?1 was obtained at acetate fraction of 0.571, propionate 0.143 and butyrate 0.286 in the total amount of VFA. The response surface methodology appears to be a useful approach to select appropriate substrate compositions for H₂ production. Under the conditions in this work, the fractions of 0.551–0.566 for acetate, 0.204–0.211 for propionate, and 0.230–0.238 for butyrate were optimal for H₂ production by Rhodopseudomonas capsulata. Copyright © 2005 Society of Chemical Industry     

Palmitic Acid Lipotoxicity in Microglia Cells Is Ameliorated by Unsaturated Fatty Acids

Obesity and metabolic syndrome are associated with cognitive decline and dementia. Palmitic acid (PA) is increased in the cerebrospinal fluid of obese patients with cognitive impairment. This study was therefore designed to examine fatty acid (FA) lipotoxicity in BV2 microglia cells. We found that PA induced time- and dose-dependent decrease in cell viability and increase in cell death without affecting the cell cycle profile and that PA lipotoxicity did not depend on cell surface free fatty acid receptors but rather on FA uptake. Treatment with sulfosuccinimidyl oleate (SSO), an irreversible inhibitor of fatty acid translocase CD36, significantly inhibited FA uptake in BSA- and PA-treated cells and blocked PA-induced decrease in cell viability. Inhibition of ER stress or treatment with N-acetylcysteine was not able to rescue PA lipotoxicity. Our study also showed that unsaturated fatty acids (UFAs), such as linoleic acid (LA), oleic acid (OA), α-linolenic acid (ALA), and docosahexaenoic acid (DHA), were not lipotoxic but instead protected microglia against PA-induced decrease in cell viability. Co-treatment of PA with LA, OA, and DHA significantly inhibited FA uptake in PA-treated cells. All UFAs tested induced the incorporation of FAs into and the amount of neutral lipids, while PA did not significantly affect the amount of neutral lipids compared with BSA control.     

ω3 Fatty acids increase spontaneous release of cytosolic components from tumor cells

Mice fed menhaden (fish) oil or coconut oil-rich diets were inoculated intraperitoneally with a rapidly growing leukemia, T27A. After one week, the tumor cells were harvested, and⁵¹Cr was used to label intracellular molecules. Spontaneous release of⁵¹Cr was used as a measure of plasma membrane permeability. Compared to cells from mice fed coconut oil (rich in saturated fatty acids), tumor cells from mice fed menhaden oil (rich in long chain polyunsaturated ω3 fatty acids) showed an increased level of spontaneous⁵¹Cr release, which was exacerbated by increased temperature and reduced by extracellular protein. At physiological salt concentrations, the releated⁵¹Cr was detected in particles of ∼2700 daltons. Enhanced permeability correlated with the incorporation of dietary (fish oil) ω3 polyunsaturated fatty acids docosahexaenoic and eicosapentaenoic acid into the tumor cells. The results demonstrate that ω3 fatty acids are incorporated into cellular constituents of tumor cells and change properties associated with the plasma membrane. This result suggests that dietary manipulation may be used to enhance tumor cell permeability and contribute to tumor eradication.     

Effect of Fatty Acid Unsaturation on Phytosteryl Ester Degradation

This study examined the thermo-oxidative degradation of stigmasterol fatty acids esters. Stigmasterol stearate, oleate, linoleate and linolenate were synthesized by chemical esterification and their purity evaluated by ¹H-NMR and GC–MS. The degradation of stigmasterol esters was examined after heating them at 60 and 180 °C for 1, 2, 4, 8 and 12 h. It was established that stigmasterol esters were prone to thermo-oxidative degradation, with time and temperature affecting the degree of degradation. The unsaturation of fatty acids affected the rate of stigmasteryl ester degradation. The kinetics of StS and StO degradation were similar and the additional double bonds in StL and StLn resulted in their faster decomposition. The esters degraded faster at 180 than at 60 °C. The sterol and fatty acid molecules degraded at different rates, such that the fatty acid moiety deteriorated faster than the sterol at both temperatures, independent of the time of heating and the level of unsaturation.     

Continuous Gradient Temperature Raman Spectroscopy of Oleic and Linoleic Acids from −100 to 50 °C

We analyzed the unsaturated fatty acids oleic (OA, 18:1n‐9) and linoleic (LA, 18:2n‐3), and a 3:1 LA:OA mixture from ?100 to 50 °C with continuous gradient temperature Raman spectroscopy (GTRS). The 20 Mb three‐dimensional data arrays with 0.2 °C increments and first/second derivatives allowed rapid, complete assignment of solid, liquid, and transition state vibrational modes. For OA, large spectral and line width changes occurred in the solid state γ to α transition near ?4 °C, and the melt (13 °C) over a range of only 1 °C. For LA, major intensity reductions from 200 to 1750 cm^?1 and some peak shifts marked one solid state phase transition at ?50 °C. A second solid state transition (?33 °C) had minor spectral changes. Large spectral and line width changes occurred at the melt transition (?7 °C) over a narrow temperature range. For both molecules, melting initiates at the diene structure, then progresses towards the ends. In the 3:1 LA:OA mixture, some less intense and lower frequencies present in the individual lipids are weaker or absent. For example, modes assignable to C8 rocking, C9H–C10H wagging, C10H–C11H wagging, and CH3 rocking are present in OA but absent in LA:OA. Our data quantify the concept of lipid premelting and identify the flexible structures within OA and LA, which have characteristic vibrational modes beginning at cryogenic temperatures.     

Modulation of phorbol ester-associated events in epidermal cells by linoleate and arachidonate

To elucidate the events elicited by the skin tumor promotor 12-O-tetradecanoylphorbol-13-acetate (TPA), which are modulated by linoleic acid (LA) and arachidonic acid (AA), the activity of these fatty acids in cultured mouse epidermal cells was compared. Approximately 94% of either exogenous radiolabelled fatty acid was incorporated into the total phospholipid pool over 15 h. The relative distribution among the phospholipid classes differed, however, such that approximately 70% of phospholipid-associated [¹⁴C]-LA was found in phosphatidylcholine, compared to approximately 30% for [¹⁴C]AA. Phosphatidylethanolamine and phosphatidylinositol/phosphatidylserine contained 17 and 13% of the phospholipid [¹⁴C]LA, and 34 and 30% of [¹⁴C]AA, respectively. Prostaglandin (PG) E₂ production was low but similar in unstimulated cultures prelabelled with either [¹⁴C]LA or [¹⁴C]AA. However, in cultures treated with TPA (1.6 μM), [¹⁴C]AA-prelabelling resulted in approximately three times the amount of [¹⁴C]PGE₂ compared with cultures prelabelled with [¹⁴C]LA. Cultured cells were found to contain significant δ6 desaturase activity, which may enable conversion of LA to AA, and thus may account for the observed PGE₂ production from [¹⁴C]LA treated cells. AA-Supplemented (1.6 μM) cultures supported approximately twice the induction of ornithine decarboxylase activity by TPA compared with cultures treated with 1.8 μM LA. Activation of partially purified protein kinase C was similar for either fatty acid tested over a 10–300 μM dose range. Overall, the results suggest that LA does not have the same biological activity as AA with regard to several TPA-associated events known to be important in skin tumor promotion. This reduced biological activity of LA may be partly responsible for the known inhibition of mouse skin tumor promotion by high dietary levels of LA [Leyton, J., Lee, M.L., Locniskar, M.F., Belury, M.A., Slaga, T.J., Bechtel, D., and Fischer, S.M. (1991)Cancer Res. 51, 907–915].     

Metabolic Conversion of C20 Polymethylene-Interrupted Polyunsaturated Fatty Acids to Essential Fatty Acids

Polymethylene-interrupted (PMI)-polyunsaturated fatty acids (PUFA) are fatty acids present largely in gymnosperm. Sciadonic acid (SciA, 20:3 Δ-5,11,14) and juniperonic acid (JA, 20:4 Δ-5,11,14,17) are typical C20 PMI-PUFA with an isolated double bond at Δ5. Previously, we found that SciA and JA are converted to linoleic acid (LNA) and α-linolenic acid (ΑLA), respectively. The conversion process includes chain-shortening step by peroxisomal β-oxidation for elimination a double bond at Δ5, and subsequent chain-elongation step in microsomes. In this study, we examined the substrate specificity of this metabolism in rodent and human cells. Supplementation of SciA, eicosadienoic acid (EDA, 20:2 Δ-11,14) or JA to CHO-K1 cells (wild type) induced an accumulation of LNA, LNA or ALA, respectively, in cellular lipids. These changes were not observed in the peroxisomes-deficient CHO cells, indicating involvement of peroxisomes in the metabolism. Two types of human cells (MKN74 and HepG2) also converted the C20 PMI-PUFA and EDA to the respective essential fatty acids. In contrast, no chain-shortened metabolite of pinolenic acid (18:3 Δ-5,9,12) was detected in any cell lines tested. From these results, C20 PMI-PUFA and EDA, but not C18 PMI-PUFA, are suggested as being effectively converted to essential fatty acids by the fatty acid remodeling system in rodent and human cells.     

<Emphasis Type="Italic">De novo</Emphasis> Synthesis of Linoleic Acid in Multiple Collembola Species

Many ecological interactions in communities take place between consumers and the organisms they feed on. Continuous surplus of specific nutritional compounds in the diet may lead to evolutionary changes in the metabolic capacity of the consumer, leaving the biosynthesis of such compounds prone to genetic decay and render organisms auxotrophic. A nutrient that is essential to many organisms is the unsaturated fatty acid, linoleic acid (LA; 18:2n-6), which is important in the maintenance of cell membrane fluidity and as a precursor for signaling molecules. LA is readily synthesized in bacteria, protozoa and plants, but it was long thought that all animals lack this ability. Although the majority of animals lack the ability for LA biosynthesis, an increasing number of studies have shown that LA is commonly synthesized in arthropods. Here, we investigated a basal hexapod group, Collembola, to shed light on early evolution of LA synthetic ability in arthropods and its relation to dietary composition. We use stable isotope labeling to detect biosynthesis of LA in Collembola fed with ¹³C–OA oleic acid (OA; 18:1n-9), a precursor of LA. Our data demonstrate that LA biosynthesis is common among Collembola with 10 out of 16 tested species being able to synthesize LA and 4 species lacking this ability. However, we did not find clear evidence for a relationship between LA synthetic ability and the natural diet of species. Thus, the selective pressures underlying LA biosynthesis might be species-specific and further research will shed new light on understanding this evolutionary process.