Double Bond Index Research Articles

Exploring Local Maize Diversity for Increased Agricultural Sustainability: New Insights into Drought Stress Response and Recovery of Guinea-Bissau Landraces

Landraces are rightfully known as the backbone of sustainable food production, particularly in areas experiencing significant environmental constraints. However, protecting landraces from genetic erosion and valuing their potential for plant breeding and sustainable food production requires in-depth understanding of their phenotypic traits. Two Guinea-Bissau landraces (GA, GV) and two elite cultivars (P98438, P0023) were subjected to drought stress for 7 (S1) and 12 (S2) days. After this period plants were rewatered (R). The relative water content (RWC) was unchanged in S1 and decreased in S2 in all genotypes. Chlorophyll a fluorescence parameters changed moderately in S1 and remarkably in S2, including on GA and GV plants, where a decrease of Fv/Fm and PI, and an increase in absorbed, trapped, and dissipated energy per reaction center, was found. P0023 plants showed the most contrasting behavior to Guinea-Bissau genotypes, presenting an increase in Fv/Fm and PI values and a decrease in the specific energy fluxes per reaction center (RC), whereas P9838 presented an intermediate behavior. Drought (S1 and S2) decreased the amount of chlorophyll (Chl.) and carotenoids in GA and GV plants. On the contrary, in the P0023, the only pigment to decrease with stress was Chl. b. Fatty acid (FA) analyses allowed for the identification of C16:0, C18:2, and C18:3 in larger amounts, and C14:0, C16:1t, C18:0, and C18:1 acids in lower abundance. Drought stress decreased C18:3, the double bond index, and the total FA (except for P0023 and GV in S2) and increased C14:0 and C16:0 acids. The expression of phospholipase D (PLD) was higher at S2. After recovery, PLD expression presented a notorious decrease on the Guinea-Bissau landraces. P0023 showed the smallest alterations after recovery, while Guinea’s plants suffered more radical alterations leading to the conclusion that Guinea’s landraces were more drought-sensitive and that their recovery rate was impaired.

Pathogenicity and Lipid Composition of Mycelium of the Fungus Stagonospora cirsii VIZR 1.41 during Submerged Cultivation

In order to identify qualitative markers of a potential mycoherbicide against Canada thistle based on the mycelium of the fungus Stagonospora cirsii VIZR 1.41, changes in its pathogenicity and lipid profiles during submerged cultivation on liquid sucrose-soybean medium were analyzed. The fatty-acid composition of major lipids and the identification of molecular species of structural lipids were determined. The lipid composition during fungal growth changed together with its pathogenicity. The highly pathogenic mycelium of the fungus (at the log phase of growth) was characterized with the relatively highest content of structural lipids: phosphatidylcholine (PC), phosphatidylethanolamine (PE), and ergosterol (ES). Their relative concentration decreased with culture age and a decrease in pathogenicity. The highest lipid yield was found at the beginning of stationary growth phase (at the maximal biomass yield) of S. cirsii; triacylglycerides (TAGs) were the most abundant. The double-bond index of fatty acids in glycerolipids decreased with culture age, and the substitution of molecular PC species (34:2 versus 36:4) and PE (36:4 versus 34:2) was observed as well. High levels of ES, TAG, PC (in particular, 34:2 forms) and PE (36:4 forms) were presumed to be qualitative markers of S. cirsii mycelium.

The toc132toc120 heterozygote mutant of Arabidopsis thaliana accumulates decreased levels of the major chloroplast lipids

We used ESI-MS/MS to profile glycerolipids in a mutant of Arabidopsis thaliana that is null and heterozygous for the TOC132 and TOC120 genes, and is referred to as the toc132toc120± mutant. The goal was to assess the impact of a defective atToc132/120 receptor on the accumulation of chloroplast lipids. The mutant accumulated decreased amounts of monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG) and phosphatidylglycerol (PG). In the cold-acclimated mutant, PG accumulated at the control levels. However, 34:4-PG (18:3/16:1Δ3trans) was significantly decreased, which indicates that the mutant was impaired in synthesis of the chloroplast-derived PG. Major molecular species of MGDG and DGDG were significantly decreased, which was indicative of the decreased levels of triunsaturated fatty acids in galactolipids. The cold-acclimated mutant accumulated increased levels of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS), which indicate that defect in the atToc132/120 receptor did not impair the ER pathway of lipid synthesis. Both cold-acclimated wildtype and mutant plants accumulated increased levels of phosphatidic acid (PA). The increased levels of major molecular species of PA suggest that some pool of PA was derived from degradation of both the chloroplast and extra-chloroplast lipids. The cold-acclimated mutant had decreased double bond index (DBI) and increased acyl chain length (ACL), which was indicative of decreased membrane fluidity. However, a decrease in the ratio of MGDG to DGDG indicate that the mutant was capable of remodeling membrane lipids in response to low temperatures. We conclude that the defective Toc132/120 receptor resulted in decreased synthesis of chloroplast lipids and decreased membrane fluidity.

Biodegradation of Unpretreated Low-Density Polyethylene (LDPE) by Stenotrophomonas sp. and Achromobacter sp., Isolated From Waste Dumpsite and Drilling Fluid.

Exploring the catabolic repertoire of natural bacteria for biodegradation of plastics is one of the priority areas of biotechnology research. Low Density Polyethylene (LDPE) is recalcitrant and poses serious threats to our environment. The present study explored the LDPE biodegradation potential of aerobic bacteria enriched from municipal waste dumpsite and bentonite based drilling fluids from a deep subsurface drilling operation. Considerable bacterial growth coupled with significant weight loss of the LDPE beads (∼8%), change in pH to acidic condition and biofilm cell growth around the beads (CFU count 105–106/cm2) were noted for two samples (P and DF2). The enriched microbial consortia thus obtained displayed high (65–90%) cell surface hydrophobicity, confirming their potential toward LDPE adhesion as well as biofilm formation. Two LDPE degrading bacterial strains affiliated to Stenotrophomonas sp. and Achromobacter sp. were isolated as pure culture from P and DF2 enrichments. 16S rRNA gene sequences of these isolates indicated their taxonomic novelty. Further biodegradation studies provided strong evidence toward the LDPE metabolizing ability of these two organisms. Atomic Fore Microscopy (AFM) and Scanning Electron Microscopy (SEM) revealed considerable damage (in terms of formation of cracks, grooves, etc.) on the micrometric surface of the LDPE film. Analysis of the average roughness (Ra), root mean square roughness (Rq), average height (Rz), maximum peak height (Rp), and maximum valley depth (Rv) (nano-roughness parameters) through AFM indicated 2–3 fold increase in nano-roughness of the LDPE film. FTIR analysis suggested incorporation of alkoxy (1000–1090 cm–1), acyl (1220 cm–1), nitro (1500–1600 cm–1), carbonyl (1720 cm–1) groups into the carbon backbone, formation of N-O stretching (1360 cm–1) and chain scission (905 cm–1) in the microbially treated LDPEs. Increase in carbonyl index (15–20 fold), double bond index (1.5–2 fold) and terminal double bond index (30–40 fold) confirmed that biodegraded LDPEs had undergone oxidation, vinylene formation and chain scission. The data suggested that oxidation and dehydrogenation could be the key steps allowing formation of low molecular weight products suitable for their further mineralization by the test bacteria. The study highlighted LDPE degrading ability of natural bacteria and provided the opportunity for their development in plastic remediation process.

The TOC159 null mutant of Arabidopsis thaliana is impaired in the accumulation of plastid lipids and phosphatidylcholine

We used electrospray ionization tandem mass spectrometry to profile glycerolipids in the TOC159 null mutant of Arabidopsis, which is referred to as plastid protein import 2, or ppi2. The goal was to evaluate the impact of a defective atToc159 receptor in the accumulation of plastid lipids. The ppi2 mutant is severely impaired in the accumulation of monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG) and phosphatidylglycerol (PG), which are major components of the thylakoid membranes. Major molecular species of MGDG and DGDG are drastically decreased, which is consistent with our previous findings of decreased levels of hexadecatrienoic and linolenic acids. Under normal growth conditions, the ppi2 mutant accumulated significantly lower levels of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI). In the cold-acclimated mutant, the amounts of PE and PI were similar to the wildtype level, which indicates that the ER pathway of lipid synthesis was functional in the mutant. The cold-acclimated ppi2 mutant accumulated increased amounts of phosphatidic acid (PA), which was mirrored by an increase in phospholipase Dα (PLDα) transcript levels. These data suggest that PLDα activity contributed to the accumulation of cold-induced PA in the ppi2 mutant. The accumulation of major molecular species in PA indicates that cold-induced PA originated from the degradation of both plastidial and extraplastidial lipids. Compared with the wildtype, the ppi2 mutant had a low double bond index and high acyl chain length, which is indicative of decreased membrane fluidity. Taken together, these data indicate that a defective atToc159 receptor severely impaired the plastid pathway of lipid synthesis, which negatively affected the synthesis and/or accumulation of PC.

Comprehensive evaluation of physiological traits under nitrogen stress and participation of linolenic acid in nitrogen-deficiency response in wheat seedlings

BackgroundNitrogen (N) deficiency is a major constraint for plant production in many areas. Developing the new crop genotypes with high productivity under N deficiency is an important approach to maintain agricultural production. Therefore, understanding how plant response to N deficiency and the mechanism of N-deficiency tolerance are very important for sustainable development of modern crop production.ResultsIn this study, the physiological responses and fatty acid composition were investigated in 24 wheat cultivars under N-deficient stress. Through Pearson’s correlation analysis and principal component analysis, the responses of 24 wheat cultivars were evaluated. The results showed that the plant growth and carbohydrate metabolism were all differently affected by N deficiency in all tested wheat cultivars. The seedlings that had high shoot biomass also maintained high level of chlorophyll content under N deficiency. Moreover, the changes in fatty acid composition, especially the linolenic acid (18:3) and the double bond index (DBI), showed close positive correlations with the shoot dry weight and chlorophyll content alterations in response to N-deficient condition. These results indicated that beside the chlorophyll content, the linolenic acid content and DBI may also contribute to N-deficiency adaptation, thus could be considered as efficient indicators for evaluation of different response in wheat seedlings under N-deficient condition.ConclusionsThe alteration in fatty acid composition can potentially contribute to N-deficiency tolerance in plants, and the regulation of fatty acid compositions maybe an effective strategy for plants to adapt to N-deficient stress.

Delayed greening in phosphorus-efficient Hakea prostrata (Proteaceae) is a photoprotective and nutrient-saving strategy.

Hakea prostrata R.Br. (Proteaceae) shows a 'delayed greening' strategy of leaf development characterised by reddish young leaves that become green as they mature. This trait may contribute to efficient use of phosphorus (P) during leaf development by first investing P in the development of leaf structure followed by maturation of the photosynthetic machinery. In this study, we investigated the properties of delayed greening in a highly P-efficient species to enhance our understanding of the ecological significance of this trait as a nutrient-saving and photoprotective strategy. In glasshouse-grown plants, we assessed foliar pigments, fatty acids and nutrient composition across five leaf developmental stages. Young leaves had higher concentrations of anthocyanin, P, nitrogen (N), copper (Cu), xanthophyll-cycle pigments and saturated fatty acids than mature leaves. As leaves developed, the concentration of anthocyanins decreased, whereas that of chlorophyll and the double bond index of fatty acids increased. In mature leaves, ~60% of the fatty acids was α-linolenic acid (C18:3 n-3). Mature leaves also had higher concentrations of aluminium (Al), calcium (Ca) and manganese (Mn) than young leaves. We conclude that delayed greening in H. prostrata is a strategy that saves P as well as N and Cu through sequential allocation of these resources, first to cell production and structural development, and then to supplement chloroplast development. This strategy also protects young leaves against photodamage and oxidative stress during leaf expansion under high-light conditions.

Decreased R:FR Ratio in Incident White Light Affects the Composition of Barley Leaf Lipidome and Freezing Tolerance in a Temperature-Dependent Manner

In cereals, C-repeat binding factor genes have been defined as key components of the light quality-dependent regulation of frost tolerance by integrating phytochrome-mediated light and temperature signals. This study elucidates the differences in the lipid composition of barley leaves illuminated with white light or white light supplemented with far-red light at 5 or 15 °C. According to LC-MS analysis, far-red light supplementation increased the amount of monogalactosyldiacylglycerol species 36:6, 36:5, and 36:4 after 1 day at 5 °C, and 10 days at 15 °C resulted in a perturbed content of 38:6 species. Changes were observed in the levels of phosphatidylethanolamine, and phosphatidylserine under white light supplemented with far-red light illumination at 15 °C, whereas robust changes were observed in the amount of several phosphatidylserine species at 5 °C. At 15 °C, the amount of some phosphatidylglycerol species increased as a result of white light supplemented with far-red light illumination after 1 day. The ceramide (42:2)-3 content increased regardless of the temperature. The double-bond index of phosphatidylglycerol, phosphatidylserine, phosphatidylcholine ceramide together with total double-bond index changed when the plant was grown at 15 °C as a function of white light supplemented with far-red light. white light supplemented with far-red light increased the monogalactosyldiacylglycerol/diacylglycerol ratio as well. The gene expression changes are well correlated with the alterations in the lipidome.

Identification of the NaCl-responsive metabolites in Citrus roots: A lipidomic and volatomic signature

ABSTRACT It is known that the first osmotic phase affects the growth rates of roots immediately upon addition of salt; thus, dissecting metabolites profiling provides an opportunity to throw light into the basis of plant tolerance by searching for altered signatures that may be associated with tolerance at this organ. This study examined the influence of salt treatment on fatty acid composition and chemical composition of the essential oil of C. aurantium roots. Results proved that, under salt treatment, an increase of double bond index and linoleic desaturation ratio was pointed out. On the other hand, the reduction of saturated fatty acids was spotted. Such treatment also induced quantitative changes in the chemical composition of the essential oils from C. aurantium roots and increased markedly the rates of monoterpenes, while the sesquiterpenes decreased significantly. Both primary and secondary metabolites were found to be significantly salt responsive, including one fatty acid (palmitoleic acid) and six volatiles (E-2-dodecenal, tetradecanal, γ-Elemene, trans-caryophyllene, α-Terpinene and germacrene D). Plasticity at the metabolic level may allow Citrus plants to acclimatize their metabolic ranges in response to changing environmental conditions.

Specific Composition of Lipid Phases Allows Retaining an Optimal Thylakoid Membrane Fluidity in Plant Response to Low-Temperature Treatment.

Thylakoid membranes isolated from leaves of two plant species, the chilling tolerant (CT) pea and chilling sensitive (CS) runner bean, were assessed for the composition of lipids, carotenoids as well as for the arrangement of photosynthetic complexes. The response to stress conditions was investigated in dark-chilled and subsequently photo-activated detached leaves of pea and bean. Thylakoids of both species have a similar level of monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), but different sulfoquinovosyldiacylglycerol to phosphatidylglycerol (PG) ratio. In pea thylakoid fraction, the MGDG, DGDG and PG, have a higher double bond index (DBI), whereas bean thylakoids contain higher levels of high melting point PG. Furthermore, the lutein to the β-carotene ratio is higher in bean thylakoids. Smaller protein/lipid ratio in pea than in bean thylakoids suggests different lipid-protein interactions in both species. The differences between species are also reflected by the course of temperature-dependent plots of chlorophyll fluorescence pointing various temperatures of the lipid phase transitions of pea and bean thylakoids. Our results showed higher fluidity of the thylakoid membrane network in pea than in bean in optimal temperature conditions. Dark-chilling decreases the photochemical activity and induces significant degradation of MGDG in bean but not in pea leaves. Similarly, substantial changes in the arrangement of photosynthetic complexes with increase in LHCII phosphorylation and disturbances of the thylakoid structure take place in bean thylakoids only. Changes in the physical properties of bean thylakoids are manifested by the conversion of a three-phase temperature-dependent plot to a one-phase plot. Subsequent photo-activation of chilled bean leaves caused a partial restoration of the photochemistry and of membrane physical properties, but not of the photosynthetic complexes arrangement nor the thylakoid network structure. Summarizing, the composition of the thylakoid lipid matrix of CT pea allows retaining the optimal fluidity of its chloroplast membranes under low temperatures. In contrast, the fluidity of CS bean thylakoids is drastically changed, leading to the reorganization of the supramolecular structure of the photosynthetic complexes and finally results in structural remodeling of the CS bean thylakoid network.

Alleviation of pericarp browning in harvested litchi fruit by synephrine hydrochloride in relation to membrane lipids metabolism

Abstract This study investigated the effect of synephrine hydrochloride (Syn-HCl) on litchi pericarp browning and the potential regulating mechanism. Results showed that 0.5 g L−1 Syn-HCl significantly inhibited the development of pericarp browning. Compared to control, Syn-HCl treatment reduced malondialdehyde and H2O2 content and inhibited activities of polyphenol oxidase (PPO) and peroxidase (POD). Meanwhile, Syn-HCl-treated litchi fruit exhibited higher amounts of USFA (unsaturated fatty acids) as well as lower amounts of SFA (saturated fatty acids) through regulating activities of membrane lipids-degrading enzymes: lipase and lipoxygenase. Additionally, higher ratio of USFA to SFA and double bond index were shown in Syn-HCl-treated fruit. Further analysis showed that key genes involved in fatty acid synthesis were also regulated by Syn-HCl treatment. Taken together, these findings indicated that Syn-HCl alleviated litchi pericarp browning resulting from regulation of fatty acid metabolism and maintenance of membrane integrity, which inhibited the enzymatic browning caused by PPO and POD.

Variation of seed oil content, oil yield, and fatty acids profile in Iranian Nigella sativa L. landraces

Since there are several diverse landraces across Iran, screening the landraces with high production may lead to finding superior genotype(s) for the future conventional breeding programs. Thus, the aims of this study was to investigate the variation of oil content, yield, and profile of fatty acids in Iranian landraces of Nigella sativa L. Seed yield, oil content and oil yield significantly differed among landraces. The highest seed and oil yields were obtained from Semirom (1250 and 332 kg ha−1). Twelve different fatty acids were detected. Linoleic acid (18:2) had the highest concentration in oil of N. sativa landraces with a range of 48–55 %. After linoleic acid, oleic (18:2) and palmitic (16:0) acids, with an average of 22 and 13 %, accounted for the highest percentage of seed oil compared with the other fatty acids. Saturated fatty acids (∑SFA) was significantly different among the landraces and included 19–22 % and 21–24 % of total fatty acids. Double bond index (DBI) was significantly different among landraces and ranged between 136.5–145.3 in 2018 and 127.5–134.5 in 2019. The Gardmiran landrace had the highest Iodine value (IV) (111.7, an average of two years) and Khaf landrace had the lowest IV (105.7, in average of two years) compared with the other landraces. Cluster analysis indicated that the landraces can be divided into three groups; (1) high yield (>1000 kg ha-1 seeds and >250 kg ha−1 oil), (2) medium yield (700–1000 kg ha−1 seeds and 190–250 kg ha−1 oil), and low yield (<700 kg ha−1 seeds and <190 kg ha−1 oil) landraces. Iranian landraces were similar in fatty acid compositions and conventional breeding methods may not be a good choice to improve a special fatty acid. However, a large variations existed in seed and oil yield among the landraces for the future conventional breeding programs.

Lipid Composition of Three Bermudagrasses in Response to Chilling Stress

Cell and plastid membranes play a critical role in plant response to chilling stress. Fall color retention (chilling tolerance) of bermudagrass (Cynodon sp.) is known to vary with cultivar and management practices. A growth chamber study was conducted to characterize the lipid composition of three bermudagrasses in response to chilling stress. The grasses selected were ‘Tahoma 31’ (chilling-sensitive) and ‘Tifway’ (chilling-tolerant) interspecific hybrid bermudagrass (C. dactylon × C. transvaalensis) and ‘Celebration’ common bermudagrass (C. dactylon), which served as an internal standard. Plants were subjected to simulated fall conditions defined as an 8/2 °C (day/night) temperature regime with 10-hour photoperiod and evaluated for chilling response for 42 days before allowing plants to enter an apparent dormancy. Plant leaves were sampled for lipidomics analysis at 0, 14, and 42 days of chilling treatment (DOT) and again after 40 days of recovery from dormancy (during which temperatures were adjusted to mimic average spring conditions for Oklahoma). ‘Tifway’ demonstrated the lowest electrolyte leakage (EL) and visual discoloration at 42 DOT, while ‘Tahoma 31’ had the greatest EL and discoloration on the same date, and ‘Celebration’ was intermediate of the two. Prolonged exposure to chilling stress generally increased digalactosyldiacylglycerol and phosphatidylcholine (PC) content and decreased monogalactosyldiacylglycerol (MGDG) content, with ‘Tahoma 31’ showing the greatest increase in PC and decrease in MGDG. The double bond index, an indicator of fatty acid unsaturation, was greatest in ‘Tifway’ at 42 DOT. Each cultivar increased in fatty acid unsaturation, with Tifway demonstrating the greatest increase in MGDG unsaturation. Multivariate discriminant analysis identified six individual lipid species that contributed most to the cultivar response to chilling. These findings suggest unsaturation level of plastid lipids, particularly MGDG, is important for chilling tolerance and therefore fall color retention of bermudagrass. Furthermore, this study provides evidence that chilling tolerance can be negatively associated with freezing tolerance in bermudagrass.

The Fatty Acid Composition of Membrane Lipids in Buds of Silver Birch during the Winter–Spring Period under the Conditions of the Cryolithozone

The fatty acid composition of polar lipids, which are the structural and functional bases of cell membranes in the bud of Betula pendula Roth birch, growing under the conditions of the cryolithozone, was studied for the first time. The important role played by lipid metabolism in the winter–spring period, when the apical meristem is at the stage of intrarenal development, was established. It was shown that, during this period, unsaturated fatty acids prevail over saturated in phospholipids and glycolipids in silver birch buds. However, under the conditions of extremely low air temperatures (–40°C and below), the lowest values of double bond index (DBI) and fatty acid unsaturation coefficient (U/S) were recorded. The rise of negative temperatures under the conditions of the cryolithozone (in March) to values usually observed during the winter period throughout the range of silver birch (–20°C and higher) contributed to an increase in the level of membrane lipid unsaturation. It was found that diene fatty acids predominate in phospholipids, and diene and triene acids predominate in glycolipids, the latter reaching maximum values (80.7% of the amount of unsaturated fatty acids) by the beginning of budding. It was hypothesized that, in order to preserve the viability of the apical meristem in buds of silver birch trees under the specific conditions of the cryolithozone, various interrelated adaptive mechanisms were formed. These mechanisms are aimed not only at protecting the rudimentary organs from the effects of sharp fluctuations in daily temperatures during spring, but also at protecting them during winter under conditions of extremely low temperatures (down to –60°С), which do not occur in other parts of its range. One of these mechanisms appeared to be nonspecific, and it was associated with an increase in the unsaturation of the fatty acid composition corresponding to the liquid-crystalline state of membrane lipids. Another adaptive mechanism is probably aimed at protecting cells from dehydration with the involvement of dehydrin proteins, as well as a number of other hydrophilic cryoprotective compounds against the background of increased viscosity of membrane lipids.

From low to high latitudes: changes in fatty acid desaturation in mammalian fat tissue suggest a thermoregulatory role

BackgroundMost fatty acids (FAs) making up the adipose tissue in mammals have a dietary origin and suffer little modification when they are stored. However, we propose that some of those FAs, specifically those that can be synthesised or modified by mammals, are also being influenced by thermal forces and used as part of the mechanism to regulate core body temperature. As FA desaturation increases, adipose tissues can reach colder temperatures without solidifying. The ability to cool the superficial fat tissues helps create a thermal gradient, which contributes to body heat loss reduction. Therefore, it is expected that animals exposed to colder environments will possess adipose tissues with higher proportions of desaturated FAs. Here, through a model selection approach that accounts for phylogeny, we investigate how the variation in FA desaturation in 54 mammalian species relates to the thermal proxies: latitude, physical environment (terrestrial, semi-aquatic and fully-aquatic) and hair density.ResultsThe interaction between the environment (terrestrial, semi- or fully-aquatic) and the latitude in which the animals lived explained best the variation of FA desaturation in mammals. Aquatic mammals had higher FA desaturation compared to terrestrial mammals. Semi-aquatic mammals had significantly higher levels of desaturated FAs when living in higher latitudes whereas terrestrial and fully-aquatic mammals did not. To account for dietary influence, a double bond index was calculated including all FAs, and revealed no correlation with latitude in any of the groups.ConclusionsWe propose that FA modification is an important component of the thermoregulatory strategy, particularly in semi-aquatic mammals. Potentially this is because, like terrestrial mammals, they experience the greatest air temperature variations across latitudes, but they lack a thick fur coat and rely primarily on their blubber. Unlike fully-aquatic mammals, extremely thick blubber is not ideal for semi-aquatic mammals, as this is detrimental to their manoeuvrability on land. Therefore, the adipose tissue in semi-aquatic mammals plays a more important role in keeping warm, and the modification of FAs becomes crucial to withstand cold temperatures and maintain a pliable blubber.

Distinct fatty acid signatures in infrapatellar fat pad and synovial fluid of patients with osteoarthritis versus rheumatoid arthritis

BackgroundInfrapatellar fat pad (IFP) has recently emerged as a potential source of inflammation in knee arthropathies. It has been proposed to be one source of adipocytokines, fatty acids (FA), and FA-derived lipid mediators that could contribute to the pathophysiological processes in the knee joint. Alterations in synovial fluid (SF) lipid composition have been linked to both osteoarthritis (OA) and rheumatoid arthritis (RA). The aim of the present study was to compare the FA signatures in the IFP and SF of RA and OA patients.MethodsPairs of IFP and SF samples were collected from the same knees of RA (n = 10) and OA patients (n = 10) undergoing total joint replacement surgery. Control SF samples (n = 6) were harvested during diagnostic or therapeutic arthroscopic knee surgery unrelated to RA or OA. The FA composition in the total lipids of IFP and SF was determined by gas chromatography with flame ionization and mass spectrometric detection.ResultsArthropathies resulted in a significant reduction in the SF proportions of n-6 polyunsaturated FA (PUFA), more pronouncedly in OA than in RA. OA was also characterized with reduced percentages of 22:6n-3 and lower product/precursor ratios of n-3 PUFA. The proportions of total monounsaturated FA increased in both RA and OA SF. Regarding IFP, RA patients had lower proportions of 20:4n-6, total n-6 PUFA, and 22:6n-3, as well as lower product/precursor ratios of n-3 PUFA compared to OA patients. The average chain length of SF FA decreased in both diagnoses and the double bond index in OA.ConclusionsThe observed complex alterations in the FA signatures could have both contributed to but also limited the inflammatory processes and cartilage destruction in the RA and OA knees.

Insights into the metabolism of membrane lipid fatty acids associated with chilling injury in post-harvest bell peppers

Bell peppers are susceptible to chilling injury (CI). To uncover the metabolism of membrane lipid fatty acids (FAs) accompanying CI, a gas chromatography-mass spectrometry (GC-MS)-based approach was used to quantitatively profile major membrane lipid FAs in bell peppers. RT-qPCR was performed to investigate the expression of the key genes that regulate the synthesis of unsaturated FAs. Additionally, we used microstructural, organoleptic, and physicochemical investigations to monitor the primary physiological metabolism of bell peppers. The study revealed that CI symptoms mostly resulted from the destabilization of the cytomembrane, which was induced by decreasing FA desaturation. Moreover, three times lower level of the double bond index in chilled fruits, than the control, further proved that membrane FA unsaturation can be considered a key factor during CI. In conclusion, this study revealed that the metabolism of membrane lipid FAs is involved in responses to CI.

Lower follicular n-3 polyunsaturated fatty acid levels are associated with a better response to ovarian stimulation.

To analyze in detail the fatty acid (FA) composition of follicular fluid (FF) from two-sized follicles at oocyte retrieval and to determine associations of the FAs from large follicles with the woman's age and the response to ovarian stimulation. Observational study. University and fertility clinic. Sixty-four women (age 19-46), consisting of unfertile patients and oocyte donors, undergoing controlled ovarian stimulation. None. FF from small (< 12mm) and large (≥ 18mm) follicles was collected at oocyte retrieval. FAs by gas chromatography-flame ionization detection. Thirty-two FAs with chain lengths ranging from 14 to 25 carbons were identified. There was a readjustment in FA distribution as follicle size increased, raising very long-chain saturated FAs, nervonic (24:1n-9), arachidonic (20:4n-6), and n-3 polyunsaturated FAs (PUFA, P < 0.001), the latter mainly due to an increase in docosahexaenoic acid (22:6n-3, DHA). In large follicles, double bond and peroxidizability indices and total n-3 PUFA, particularly DHA, correlated positively with the woman's age and negatively with the number of total and mature oocytes, total and top-quality embryos, and fertilization rate. We have described 32 FAs in ovarian FF, of which 16 changed their distribution with follicle size. The results also indicate that lower n-3 PUFA levels in large follicles, which are associated with younger women, predict a better response to ovarian stimulation based on the recovery of total and mature oocytes, total and top-quality embryos, and fertilization rate per cycle. The fatty acid profile of ovarian FF changes as the follicle grows and lower n-3 PUFA levels in large follicles, associated with younger women, predict a better response to ovarian stimulation.

Overexpression of CCCH zinc finger protein gene delays flowering time and enhances salt tolerance in Arabidopsis by increasing fatty acid unsaturation

CCCH-type zinc-finger proteins constitute a large family playing key roles during plant development and growth. In the present study, we investigated the involvement of the CCCH-type zinc finger protein of AtZFP1 (At2g25900) in flowering and salt stress response in Arabidopsis. Compared with the wild type (WT), bolting and flowering were delayed in AtZFP1-overexpressing plants. Real-time PCR analysis of floral regulating genes in overexpressing Arabidopsis revealed that enhanced expression of FLC decreased the expressions of FT and SOC1. The Fv/Fm of overexpressing Arabidopsis lines was unchanged under salt stress. In contrast, ΦPSII activity and PSI oxidoreduction decreased in WT, overexpressing and mutant strains under salt stress conditions, with the smallest reduction in these parameters observed in the overexpressing strains. These results suggest that the CCCH zinc-finger protein AtZFP1 primarily controls flowering time by changing the expression of flowering genes under long-day conditions. The overexpression of this protein delayed flowering and increased the content and double-bond index of unsaturated fatty acids. Elevation of unsaturated fatty acid content might play important role in protecting the photosynthetic apparatus and maintaining the membrane function at salt stress by alleviating PSII and PSI photoinhibition.

Root length and root lipid composition contribute to drought tolerance of winter and spring wheat

Mechanisms of drought tolerance based on root architecture and lipid composition in wheat are poorly understood. We quantified the differences in root morphological traits and phospholipids and galactolipids levels between winter and spring wheat genotypes at variable water supply amounts (drought stress). Experiments were conducted using seven winter and four spring wheat (Triticum aestivum) genotypes. In the first experiment, solid agar medium was used to quantify seminal root angles. In the second experiment, the plants were grown in 150-cm columns in a greenhouse under full and deficit water supply for 65 days to record root architecture. The root tips (2-cm-long) were used for quantifying polar lipids. Drought stress at vegetative stage decreased plant height (14%), total dry matter production (48%), maximum root length (25%), root length:shoot length ratio (11%), and other root traits. Winter wheat genotypes had ~1.5 times higher maximum root length than spring wheat genotypes. Significant differences in molar percentages of root phospholipids and galactolipids, molecular species, and double bond index of galactolipids were observed among spring wheat but not winter wheat genotypes. Based on the genotypes studied, the drought tolerant mechanism of winter wheat was associated with deep root system, and in spring wheat it was well branched (albeit shallow) root system with more unsaturated membrane lipids.