Shift In Fatty Acid Composition Research Articles

Molecular insights into the enhanced growth of cyanobacteria by adaptive laboratory evolution in wastewater environments

The expansion of population leads to an increase in nutrient-rich wastewater, posing a threat to the ecosystem. The cultivation of economically beneficial cyanobacteria consumes amounts of freshwater, exacerbating the depletion of freshwater resources. This study investigates the potential of utilizing adaptive laboratory evolution (ALE) to enhance the growth performance of Synechocystis sp. PCC 6803, a model cyanobacterium, in wastewater. After 374 days of ALE, a strain designated as WW was successfully evolved. When cultivated in wastewater, WW exhibited a specific growth rate of 0.317 per day and achieved a dry weight of 0.693 g/L by the 13th day, outperforming the wild type. WW achieved removal efficiencies of 35.55 % for total nitrogen and 60.95 % for total phosphorus in the wastewater. RNA sequencing and photosynthetic measurements revealed that enhanced photosynthetic capacity in the WW contributes to its superior growth performance. The lipid content in WW was 16.19 %, with a notable increase in the proportion of polyunsaturated fatty acids. The shift in fatty acid composition has a consequential impact on biodiesel index, including oxidation stability and saponification number. This study not only demonstrates the effectiveness of ALE in enhancing the growth of cyanobacteria in wastewater for biofuel production, but also offers significant insights into the molecular mechanisms that drive this improved performance.

Enhancing poly(3-hydroxybutyrate) production in halophilic bacteria through improved salt tolerance

Polyhydroxyalkanoates (PHA) have emerged as a promising bio-compound in the industrial application due to their potential to replace conventional petroleum-based plastics with sustainable bioplastics. This study focuses on Halomonas sp. YJPS3-3, a halophilic bacterium, and presents a novel approach to enhance PHA production by exploiting its salt tolerance toward PHA biosynthesis. Through gamma irradiation-induced mutants with enhanced salt tolerance from 15% NaCl to 20% NaCl, mutant halo6 showing a significant 11% increase in PHA yield, was achieved. Moreover, the mutants displayed not only higher PHA content but also remarkable cell morphology with elongation. In addition, this research unravels the genetic determinants behind the elevated PHA content and identifies a corresponding shift in fatty acid composition favoring PHA accumulation. This novel mutant obtained from gamma irradiation with enhanced salt tolerance in halophilic bacteria opens up new avenues not only for the bioplastic industry but also for applications in the production of high-value metabolites.

Yolk Fatty Acid Profile and Amino Acid Composition in Eggs from Hens Supplemented with ß-Hydroxy-ß-Methylbutyrate.

In recent years, a supplementation of livestock animals, including poultry, with β-Hydroxy-β-methylbutyrate (HMB) has gained attention for its effects on protein and fat metabolism. This study investigates the effects of HMB in the laying hen diet on egg quality, focusing on amino acid and fatty acid composition. Laying hens were supplemented with 0.02% HMB, with performance parameters and egg components analyzed. HMB supplementation led to increased albumen weight, influencing egg weight while also reducing feed intake per egg without affecting laying rate, yolk indices, fat, or cholesterol content. Notably, the study revealed significant changes in egg amino acid and fatty acid profiles due to HMB supplementation. Various amino acids, including glycine, serine, and isoleucine, were altered in the yolk, impacting nutritional value and potential health benefits. Regarding fatty acids, the study observed changes in both saturated as well as n-6 and n-3 fatty acids, affecting the overall lipid profile of egg yolks. However, the shifts in fatty acid composition could have implications for cardiovascular health due to altered ratios of n-6/n-3 fatty acids. Further research is required to comprehensively understand the implications of these findings for consumer-oriented egg quality and health benefits.

Effects of Iron Valence on the Growth, Photosynthesis, and Fatty Acid Composition of Phaeodactylum tricornutum

Iron is a limiting factor that controls the phytoplankton biomass of the ocean and plays an important role in the lipid production of microalgae. Elucidating the effects of different iron valences on microalgae is helpful for their commercial production. We investigated the growth, photosynthesis, and fatty acid profile of the model diatom Phaeodactylum tricornutum cultured with depleted Fe, Fe2+, Fe2+/Fe3+, and Fe3+. Samples were taken every 24 h for 8 days, and their cell density, photosynthetic pigment content, chlorophyll fluorescence, total fatty acid content, and fatty acid composition were analyzed. The cell densities of the Fe2+ and Fe2+/Fe3+ groups were significantly higher than those of the control and Fe3+ groups (p < 0.05). They were 1.26 times and 1.23 times higher than those in the Fe-depleted group. The contents of chlorophyll a and c in the Fe2+ group were significantly higher than those in the Fe-depleted group (p < 0.05). The chlorophyll fluorescence results show that Fe2+ enhanced the photosynthesis of P. tricornutum to a greater extent than Fe3+. On the eighth day of harvest, Fv/Fm and Y(II) in the Fe2+ group were 0.672 and 0.476, respectively, being 1.10 and 1.19 times greater than those in the Fe3+ group and 1.15 and 1.33 times greater than those in the Fe-depleted group, respectively. Compared with the control group, the levels of saturated fatty acids of the Fe2+/Fe3+ and Fe3+ groups were significantly higher (p < 0.05) at 21.36 ± 1.24% and 21.20 ± 0.13%, respectively. The levels of polyunsaturated fatty acids of the Fe2+/Fe3+ group were significantly lower (p < 0.05) at 29.82 ± 2.75%. Our results show that P. tricornutum exhibited physiological plasticity, including changes in photosynthetic activities and shifts in fatty acid composition, in response to different iron valences and that Fe2+ was more beneficial to the biomass production of this species than Fe3+. These findings are applicable to the production of biomass and polyunsaturated fatty acids.

The Influence of Ultrasound on the Growth of Nannochloris sp. in Modified Growth Medium.

The influence of ultrasound irradiation on the algal biomass productivity as well as its oil content and fatty acids profile, grown in a modified Zarrouk medium, i.e., deproteinized whey waste solution, was investigated. The algal samples (Nannochloris sp. 424-1 microalgae) were grown for 7 days in a thermostated incubator at 28 °C, shaken under continuous light. During this period, the algal biomass was subjected to induced stress by ultrasonic irradiation at different powers and sonication time. The obtained results demonstrate that ultrasound stressing of algae biomass has a positive effect on both the quantity of biomass and the oil obtained, also causing a shift in fatty acid composition by increasing the proportion of C16 and C18 polyunsaturated fatty acids. A low dosage level of exposure to the ultrasound led to algal biomass increase as well as lipid accumulation. For both types of irradiation modes which were investigated, daily and only initial irradiation, the beneficial effect of the ultrasound decreases as the exposure time increases and the excessive sonication becomes detrimental to microalgae growth.

Cultivation and biochemical characterization of isolated Sicilian microalgal species in salt and temperature stress conditions

In the last years, the possibility to exploit autochthone microalgae in regional applications has been explored. The regional-based microalgal industry may bring several benefits, as autochthone microalgae are already adapted to the biotic and abiotic stresses of their environment. In this work, this concept was applied to Sicily, in which three microalgal strains were collected from the coastline. Monoalgal strains were then isolated and molecular characterization was performed for the species determination. Three of them, two strains of Chlorella and one of Dunaliella, were cultivated in lab-scale in four different conditions: Low Temperature-Low Salt (LT-LS), High-Temperature-Low Salt (HT-LS), Low Temperature-High Salt (LT-HS) and High Temperature-High Salt (HT-HS) to investigate the role of each condition on the growth performance, the productivity and the biochemical composition of the microalgal biomass. In particular, lipid, fatty acid composition and antioxidant capacity were assessed. Results indicated that one of the Sicilian strains of Chlorella has a better growth performance at a higher temperature while the Dunaliella strain is tolerant to high-salt stress. Moreover, the biochemical composition appears to be strongly influenced by temperature and salt stresses: the lipid content decreased in all the strains and a significant shift in fatty acid composition was observed, with an increase in the content of n-3 PUFAs in some cases. Results indicated that also the carotenoids content decreased in some of the tested stress conditions. The results obtained in this research represent a first step for developing a regional-based microalgal industry in Sicily by exploiting the natural biodiversity of the Sicilian environment.

Enhancing lipid productivity by modulating lipid catabolism using the CRISPR-Cas9 system in Chlamydomonas

In response to the energy crisis microalgae are a promising feedstock for biofuel production. The use of metabolic engineering to improve yields of biofuel-related lipid components in microalgae, without affecting cell growth, is now recognized as a promising and more economically feasible approach to develop more sustainable energy sources. For this, we generated Chlamydomonas mutant strains using CRISPR-Cas9 technology to knockout a gene involved in fatty acid (FA) degradation. In the knockout mutant, total lipid accumulated up to 28% of dried biomass, while that of wild-type (WT) was 22%. This increase was also accompanied by a noticeable shift in FA composition with an increase up to 27.2% in the C18:1 proportion. In addition, these mutants showed comparable growth rate to the WT, indicating that inhibiting lipid catabolism through gene editing technology is a promising strategy to develop microalgal strains for biofuel production.

Homocysteine regulates fatty acid and lipid metabolism in yeast

S-Adenosyl-l-homocysteine hydrolase (AdoHcy hydrolase; Sah1 in yeast/AHCY in mammals) degrades AdoHcy, a by-product and strong product inhibitor of S-adenosyl-l-methionine (AdoMet)-dependent methylation reactions, to adenosine and homocysteine (Hcy). This reaction is reversible, so any elevation of Hcy levels, such as in hyperhomocysteinemia (HHcy), drives the formation of AdoHcy, with detrimental consequences for cellular methylation reactions. HHcy, a pathological condition linked to cardiovascular and neurological disorders, as well as fatty liver among others, is associated with a deregulation of lipid metabolism. Here, we developed a yeast model of HHcy to identify mechanisms that dysregulate lipid metabolism. Hcy supplementation to wildtype cells up-regulated cellular fatty acid and triacylglycerol content and induced a shift in fatty acid composition, similar to changes observed in mutants lacking Sah1. Expression of the irreversible bacterial pathway for AdoHcy degradation in yeast allowed us to dissect the impact of AdoHcy accumulation on lipid metabolism from the impact of elevated Hcy. Expression of this pathway fully suppressed the growth deficit of sah1 mutants as well as the deregulation of lipid metabolism in both the sah1 mutant and Hcy-exposed wildtype, showing that AdoHcy accumulation mediates the deregulation of lipid metabolism in response to elevated Hcy in yeast. Furthermore, Hcy supplementation in yeast led to increased resistance to cerulenin, an inhibitor of fatty acid synthase, as well as to a concomitant decline of condensing enzymes involved in very long-chain fatty acid synthesis, in line with the observed shift in fatty acid content and composition.

Revealing the Influence of Tempering on Polymorphism and Crystal Arrangement in Semicrystalline Oil-in-Water Emulsions

The influence of tempering (i.e., successive heating and cooling) on crystallization properties of semicrystalline milk fat-in-water emulsions was studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and cryoscanning electron microscopy. Melting profiles obtained by DSC indicate a fractionation process of milk fat in every individual fat droplet. The long spacings, as observed by XRD, were useful in the designation of polymorphic changes to a shift in fatty acid composition of the crystals. An increased layer thickness of the 3L-crystals at 20 and 30 °C tempering points to a preferential incorporation of long-chain unsaturated fatty acids over short-chain fatty acids. Additionally, at 30 °C, an increased layer thickness of the 2L-crystals assumes the incorporation of longer-chain saturated fatty acids. The highly mixed crystals, an inherent property of milk fat, seem to be fractionated in purer crystals grouping triacylglycerols with a similar fatty acid composition. Moreover, a di...

Enhancement of bile resistance in Lactobacillus plantarum strains by soy lecithin.

This study evaluated the effect of soy lecithin on the bile resistance of Lactobacillus plantarum. Six strains were cultured in MRS broth supplemented with soy lecithin at different concentrations. The strains incubated in MRS broth with 1·0% soy lecithin showed no inhibitory effect on cell growth. After culturing in MRS broth with 0·2-1·0% soy lecithin, the survival rate of harvested cells increased significantly (P < 0·05) in the 0·3% bile challenge compared with the no added soy lecithin group. The cells incubated with 0·6% soy lecithin were able to grow in an MRS broth with a higher bile salt content. The surface hydrophobicity and cell leakage in the bile challenge were assessed to reveal the physical changes caused by the addition of soy lecithin. The cell surface hydrophobicity was enhanced and the membrane integrity in the bile challenge increased after culturing with soy lecithin. A shift in the fatty acid composition was also observed, illustrating the cell membrane change in the soy lecithin culture. In this study, we report for the first time the beneficial effect of adding soy lecithin to an MRS broth on subsequent bile tolerance of Lactobacillus plantarum. Soy lecithin had no inhibitory effect on strain viability but significantly enhanced bile resistance. Surface hydrophobicity and cell integrity increased in strains cultured with soy lecithin. The observed shift in the cell fatty acid composition indicated changes to the cell membrane. As soy lecithin is safe for use in the food industry, its protective effects can be harnessed for the development of bile-sensitive strains with health-benefit functions for use in probiotic products.

Unexpected shifts in fatty acid composition in response to diet in a common littoral amphipod

To determine whether fatty acid (FA) profiles are a useful biomarker to trace the flow of material in a coastal food web, we fed the sandhopper Bellor - chestia quoyana specific seaweed diets, each with a contrasting FA profile including Durvillaea antarctica (Phaeophyta), Ecklonia radiata (Phaeophyta) or Ulva sp. (Chlorophyta). We then compared changes in FA composition in relation to diet for this sandhopper. After 12 d, sandhoppers from each treatment had distinct FA profiles, particularly with respect to polyunsaturated FAs (PUFAs); however, increases in specific FAs did not relate to those FAs that were abundant in their diet. For example, sandhoppers fed PUFA-deficient Ulva sp. exhibited a relative increase in PUFAs. The E. radiata and Ulva sp. diets both caused significant shifts in sandhopper FA composition over the course of the experiment. In order to follow the assimilation of carbon and FAs, sandhoppers were fed natural or 13C-enhanced E. radiata or Ulva sp., and changes to the δ13C of individual FAs were measured over time. Turnover of the most abundant FAs, 16:0 and 18:1ω9, was higher for sandhoppers fed E. radiata than for those fed Ulva sp. Comparisons between bulk tissue δ13C and δ13C of individual FAs were consistent with sandhoppers modifying the turnover rate of FA in response to diet. These findings suggest that there is no consistent relationship between the FA compositions of green and brown seaweeds and that of the sandhopper B. quoyana. We caution that community-level application of FAs as a dietary biomarker tool must be accompanied by controlled experiments incorporating key species of relevance.

Integrative analysis of metabolite and transcript abundance during the short-term response to saline and oxidative stress in the brown alga Ectocarpus siliculosus.

The model brown alga Ectocarpus siliculosus undergoes extensive transcriptomic changes in response to abiotic stress, many of them related to primary metabolism and particularly to amino acid biosynthesis and degradation. In this study we seek to improve our knowledge of the mechanisms underlying the stress tolerance of this alga, in particular with regard to compatible osmolytes, by examining the effects of these changes on metabolite concentrations. We performed extensive metabolic profiling (urea, amino acids, sugars, polyols, organic acids, fatty acids) of Ectocarpus samples subjected to short-term hyposaline, hypersaline and oxidative stress, and integrated the results with previously published transcriptomic data. The most pronounced changes in metabolite concentrations occurred under hypersaline stress: both mannitol and proline were accumulated, but their low final concentrations indicate that, in this stress condition, both compounds are not likely to significantly contribute to osmoregulation at the level of the entire cell. Urea and trehalose were not detected in any of our samples. We also observed a shift in fatty acid composition from n-3 to n-6 fatty acids under high salinities, and demonstrated the salt stress-induced accumulation of small amounts of γ-aminobutyric acid (GABA). GABA could be synthesized in E. siliculosus through a salt stress-induced putrescine-degradation pathway.

Myc-dependent Mitochondrial Generation of Acetyl-CoA Contributes to Fatty Acid Biosynthesis and Histone Acetylation during Cell Cycle Entry

Cell reprogramming from a quiescent to proliferative state requires coordinate activation of multiple -omic networks. These networks activate histones, increase cellular bioenergetics and the synthesis of macromolecules required for cell proliferation. However, mechanisms that coordinate the regulation of these interconnected networks are not fully understood. The oncogene c-Myc (Myc) activates cellular metabolism and global chromatin remodeling. Here we tested for an interconnection between Myc regulation of metabolism and acetylation of histones. Using [(13)C(6)]glucose and a combination of GC/MS and LC/ESI tandem mass spectrometry, we determined the fractional incorporation of (13)C-labeled 2-carbon fragments into the fatty acid palmitate, and acetyl-lysines at the N-terminal tail of histone H4 in myc(-/-) and myc(+/+) Rat1A fibroblasts. Our data demonstrate that Myc increases mitochondrial synthesis of acetyl-CoA, as the de novo synthesis of (13)C-labeled palmitate was increased 2-fold in Myc-expressing cells. Additionally, Myc induced a forty percent increase in (13)C-labeled acetyl-CoA on H4-K16. This is linked to the capacity of Myc to increase mitochondrial production of acetyl-CoA, as we show that mitochondria provide 50% of the acetyl groups on H4-K16. These data point to a key role for Myc in directing the interconnection of -omic networks, and in particular, epigenetic modification of proteins in response to proliferative signals.

Effects of exogenous salicylic acid pre-treatment on cadmium toxicity and leaf lipid content in Linum usitatissimum L .

The effects of salicylic acid (SA) on cadmium (Cd) toxicity in flax plants were studied by investigating plant growth, lipid peroxidation and fatty acid composition. Cadmium inhibited biomass production as well as the absorption of K, Ca, Mg and Fe. Furthermore, it dramatically increased Cd accumulation in both roots and shoots. The pre-soaking of dry flax grains in SA-containing solutions partially protected seedlings from Cd toxicity during the following growth period. SA treatment decreased the uptake and the transport of Cd, alleviated the Cd-induced inhibition of Ca, Mg and Fe absorption and promoted plant growth. At leaf level, Cd significantly decreased both total lipid (TL) and chlorophyll (Chl) content and enhanced electrolyte leakage and lipid peroxidation as indicated by malondialdehyde (MDA) accumulation. Concomitantly, Cd caused a shift in fatty acid composition, resulting in a lower degree of their unsaturation. SA pre-soaking ameliorated the increased electrolyte leakage as well as Chl, MDA and TL content. SA particularly increased the percentage of linolenic acid and lowered that of palmitic acid by the same proportion. These results suggest that SA could be used as a potential growth regulator and a stabilizer of membrane integrity to improve plant resistance to Cd stress.

Differential Adaptive Response and Survival of Salmonella enterica Serovar Enteritidis Planktonic and Biofilm Cells Exposed to Benzalkonium Chloride

This study examined the adaptive response and survival of planktonic and biofilm phenotypes of Salmonella enterica serovar Enteritidis adapted to benzalkonium chloride (BC). Planktonic cells and biofilms were continuously exposed to 1 microg ml(-1) of BC for 144 h. The proportion of BC-adapted biofilm cells able to survive a lethal BC treatment (30 microg ml(-1)) was significantly higher (4.6-fold) than that of BC-adapted planktonic cells. Similarly, there were 18.3-fold more survivors among the BC-adapted biofilm cells than among their nonadapted (i.e., without prior BC exposure) cell counterparts at the lethal BC concentration, and this value was significantly higher than the value for BC-adapted planktonic cells versus nonadapted cells (3.2-fold). A significantly higher (P < 0.05) proportion of surviving cells was noticed among BC-adapted biofilm cells relative to BC-adapted planktonic cells following a 10-min heat shock at 55 degrees C. Fatty acid composition was significantly influenced by phenotype (planktonic cells or biofilm) and BC adaptation. Cell surface roughness of biofilm cells was also significantly greater (P < 0.05) than that of planktonic cells. Key proteins upregulated in BC-adapted planktonic and biofilm cells included CspA, TrxA, Tsf, YjgF, and a probable peroxidase, STY0440. Nine and 17 unique proteins were upregulated in BC-adapted planktonic and biofilm cells, respectively. These results suggest that enhanced biofilm-specific upregulation of 17 unique proteins, along with the increased expression of CspA, TrxA, Tsf, YjgF, and a probable peroxidase, phenotype-specific alterations in cell surface roughness, and a shift in fatty acid composition conferred enhanced survival to the BC-adapted biofilm cell population relative to their BC-adapted planktonic cell counterparts.

Sensitivity of pig genotypes to short-term manipulation of plasma fatty acids by feeding linseed

The sensitivity of pigs selected for high daily food intake (DFI), low lean food conversion (LFC) and high lean growth rate (LGS) to dietary change of plasma fatty acids was assessed. The difference between the two diets was effectively a substitution of palmitic (C16:0), oleic (C18:1 n-9) and linoleic (C18:2 n-6) with linolenic (C18:3 n-3) fatty acids. Fatty acid compositions of plasma free fatty acids, neutral lipids and phospholipids were measured in 90 kg animals fed a base or high linolenic (C18:3 n-3) fatty acid diet, based on whole linseed, for four days. There were 24 animals from each selection line and 24 animals from an unselected control line, with boars and gilts represented equally in each line. Half of the selection line animals were fed the base diet and half were fed the high C18:3 diet, but all control animals were fed the base diet. Prior to slaughter, animals were fasted for 18 h. The fatty acids primarily affected by dietary change were C18:3 n-3 and its products, C20:5 n-3 (EPA) and C22:6 n-3 (DHA). The sensitivity of a selection line to dietary change was parameterised by the relative shift in fatty acid composition through changing from the base diet to the high C18:3 diet. In neutral lipids, the sensitivities of C18:3 n-3 in the DFI and LFC lines were similar but greater than in the LGS line (3.0 v. 1.8, S.E.D. 0.15), while, for phospholipid and free fatty acids, the sensitivity of the DFI line was greater than in the LFC and LGS lines (2.3 v. 1.8 and 2.0 v. 1.4, respectively). For C20:5 n-3 and C22:6 n-3, the DFI and LFC lines were more sensitive to dietary change than the LGS line (total lipid : 2.3 v. 1.9 and 1.5 v. 1.2). In general, the DFI line was most sensitive to dietary change and the LGS line was the least sensitive. The difference in sensitivities of the lipid classes to the high C18:3 diet between the selection lines could result from differences in body fat content and may explain the general lack of genotype with nutrition interactions in post-1990 genotypes in comparison with fatter circa-1970 genotypes.

Effect of sulphur levels on transgenic double‐low Brassica napus plants expressing a seed‐specific gene encoding a methionine‐rich 2S albumin

AbstractThe effects of supplying varying levels of sulphur to transgenic Brassica napus plants expressing the Brazil nut 2S albumin in their seeds were studied in the field. The aim was to determine if transgenic plants responded differently to such stress, and whether expression of the transgene would be effected. The transgenic plants were similar to normal plants in their response to sulphur stress. Increases in sulphur concentration were correlated with an increase in fresh and dry matter quantities as well as an increase in the carbon, nitrogen and sulphur levels in the vegetative parts of the plants. No effect on yield parameters was observed. Increasing sulphur levels resulted in an increase in the glucosinolate content, and shifts in fatty acid composition were observed. None of these changes could be correlated with the response of the transgene. The expression of the latter was altered at neither the mRNA nor The protein levels, presumably because the promoter used does not respond directly to sulphur level changes. The procedures used to create the transgenic plants in this work appear not to result in plants that respond to sulphur stress differently from normal plants in the ranges studied.

A reevaluation of the effect of auxin on phospholipids in pea stem segments

Auxin has been reported to substantially alter concentration and fatty acid composition of phospholipids in elongating pea ( Pisum sativum L. cv. Feltham First) stem segments. To further investigate this phenomenon, phospholipid composition of cv. Alaska pea segments treated with the auxin 2,4-dichlorophenoxyacetic acid (2,4-D) for 30 or 60 min was analyzed. The amount of phosphatidylethanolamine (PE) was lower in 2,4-D-treated segments at 30 min, but by 60 min, the amount was comparable to controls. Quantitative differences in phosphatidylcholine (PC) and phosphatidylinositol (PI) were not significant. Auxin did not affect phospholipid fatty acid composition. Auxin did not inhibited the incorporation of [ 14C]acetate or [ 3H]choline into the major phospholipids. These results suggest that effects of auxin on phospholipid metabolism are transient, and that shifts in fatty acid composition do not universally occur in response to auxin treatment.

Rapid changes in soybean root membrane lipids with altered temperature

In soybean roots, as temperature was increased between 15° and 30°, palmitic and stearic acids increased, and oleic, linoleic, and linolenic acids decreased in both plasmalemma and mitochondrial membrane fractions. As temperature was decreased, the reverse trend occurred. Membranes in both the mitochondria and plasmalemma responded with a significant shift in fatty acid composition in 48 hr, often in 24 hr. Mitochondria responded more quickly than the plasmalemma, particularly at the lower temperature.

Variation in Lipid Composition Among Strains of Oats1

Significant relationships were detected between lipid content and total fatty acid composition of seed from Avena sativa L. With increasing lipid content, the proportions of palmitic and linoleic acid decreased while oleic acid Increased. The relative proportions of acyl lipid classes (especially phospholipids and triglycerides) were also affected; high lipid strains contained a greater proportion of triglyceride and a lower proportion of phospholipid. Although the fatty acid composition of these two lipid classes was distinctly different in each strain, both exhibited similar shifts in fatty acid composition with changing lipid content.