New bioactive oxylipins formed by non-enzymatic free-radical-catalyzed pathways: the phytoprostanes

Major Oxidative and Antioxidant Mechanisms During Heat Stress-Induced Oxidative Stress in Chickens

Heat stress (HS) is one of the most important stressors in chickens, and its adverse effects are primarily caused by disturbing the redox homeostasis. An increase in electron leakage from the mitochondrial electron transport chain is the major source of free radical production under HS, which triggers other enzymatic systems to generate more radicals. As a defense mechanism, cells have enzymatic and non-enzymatic antioxidant systems that work cooperatively against free radicals. The generation of free radicals, particularly the reactive oxygen species (ROS) and reactive nitrogen species (RNS), under HS condition outweighs the cellular antioxidant capacity, resulting in oxidative damage to macromolecules, including lipids, carbohydrates, proteins, and DNA. Understanding these detrimental oxidative processes and protective defense mechanisms is important in developing mitigation strategies against HS. This review summarizes the current understanding of major oxidative and antioxidant systems and their molecular mechanisms in generating or neutralizing the ROS/RNS. Importantly, this review explores the potential mechanisms that lead to the development of oxidative stress in heat-stressed chickens, highlighting their unique behavioral and physiological responses against thermal stress. Further, we summarize the major findings associated with these oxidative and antioxidant mechanisms in chickens.

Exploring Oxylipins in Host-Microbe Interactions and Their Impact on Infection and Immunity

Plasma lipids are essential components of biological systems, transported through interactions with proteins to maintain cellular functions. These lipids exist in various forms, such as fatty acids, glycerolipids, glycerophospholipids, sphingolipids, sterols, and prenol lipids, derived from dietary intake, adipose tissue, and biosynthesis. While the association between certain fatty acids and cardiovascular diseases has been widely recognized, polyunsaturated fatty acids (PUFAs) exhibit cardioprotective effects, reducing risks of arrhythmias and heart-related mortality. This is due to their role in the production of eicosanoids, which modulate inflammation. Chronic inflammation, particularly in obesity, is significantly influenced by fatty acids, with saturated fatty acids promoting inflammation and PUFAs mitigating it. Oxylipins, bioactive molecules derived from the oxidation of PUFAs, play crucial roles in immune regulation across various organisms, including plants, fungi, and bacteria. These molecules, such as prostaglandins, leukotrienes, and resolvins, regulate immune responses during infection and inflammation. The production of oxylipins extends beyond mammals, with fungi and bacteria synthesizing these molecules to modulate immune responses, promoting both defense and pathogenesis. This review delves into the multifaceted effects of oxylipins, exploring their impact on host and microbial interactions, with a focus on their potential for therapeutic applications in modulating infection and immune response.

Exploring lipid signaling in plant physiology: From cellular membranes to environmental adaptation

Lipids have evolved as versatile signaling molecules that regulate a variety of physiological processes in plants. Convincing evidence highlights their critical role as mediators in a wide range of plant processes required for survival, growth, development, and responses to environmental conditions such as water availability, temperature changes, salt, pests, and diseases. Understanding lipid signaling as a critical process has helped us expand our understanding of plant biology by explaining how plants sense and respond to environmental cues. Lipid signaling pathways constitute a complex network of lipids, enzymes, and receptors that coordinate important cellular responses and stressing plant biology's changing and adaptable traits. Plant lipid signaling involves a wide range of lipid classes, including phospholipids, sphingolipids, oxylipins, and sterols, each of which contributes differently to cellular communication and control. These lipids function not only as structural components, but also as bioactive molecules that transfer signals. The mechanisms entail the production of lipid mediators and their detection by particular receptors, which frequently trigger downstream cascades that affect gene expression, cellular functions, and overall plant growth. This review looks into lipid signaling in plant physiology, giving an in-depth look and emphasizing its critical function as a master regulator of vital activities.

Exploring oxylipins in processed foods: Understanding mechanisms, analytical perspectives, and enhancing quality with lipidomics

Oxylipins are active lipid compounds formed through the oxidation of unsaturated fatty acids. These compounds have drawn considerable attention due to the potential impact on human health and processed food quality. Therefore, this study aimed to deepen current understanding and assess recent analytical advancements regarding the physiological roles of oxylipins in processed food products using lipidomics. The mechanisms behind oxylipins production in processed foods were extensively investigated, underscoring potential associations with chronic diseases. This indicates the need for innovative strategies to mitigate harmful oxylipins levels to enhance the safety and shelf life of processed food products. The results showed that mitigation methods, including the use of antioxidants and optimization of processing parameters, reduced oxylipins levels. The integration of lipidomics with food safety and quality control processes is evident in cutting-edge methods such as nuclear magnetic resonance and mass spectrometry for compliance and real-time evaluation. Aside from envisioning the future trajectory of food science and industry through prospective studies on oxylipins and processed foods, the results also provide the basis for future investigations, innovation, and advancements in the dynamic field of food science and technology.

Emerging Roles and Therapeutic Applications of Arachidonic Acid Pathways in Cardiometabolic Diseases

Cardiometabolic disease has become a major health burden worldwide, with sharply increasing prevalence but highly limited therapeutic interventions. Emerging evidence has revealed that arachidonic acid derivatives and pathway factors link metabolic disorders to cardiovascular risks and intimately participate in the progression and severity of cardiometabolic diseases. In this review, we systemically summarized and updated the biological functions of arachidonic acid pathways in cardiometabolic diseases, mainly focusing on heart failure, hypertension, atherosclerosis, nonalcoholic fatty liver disease, obesity, and diabetes. We further discussed the cellular and molecular mechanisms of arachidonic acid pathway-mediated regulation of cardiometabolic diseases and highlighted the emerging clinical advances to improve these pathological conditions by targeting arachidonic acid metabolites and pathway factors.

Functions and interaction of plant lipid signalling under abiotic stresses

Lipids are the primary form of energy storage and a major component of plasma membranes, which form the interface between the cell and the extracellular environment. Several lipids - including phosphoinositide, phosphatidic acid, sphingolipids, lysophospholipids, oxylipins, and free fatty acids - also serve as substrates for the generation of signalling molecules. Abiotic stresses, such as drought and temperature stress, are known to affect plant growth. In addition, abiotic stresses can activate certain lipid-dependent signalling pathways that control the expression of stress-responsive genes and contribute to plant stress adaptation. Many studies have focused either on the enzymatic production and metabolism of lipids, or on the mechanisms of abiotic stress response. However, there is little information regarding the roles of plant lipids in plant responses to abiotic stress. In this review, we describe the metabolism of plant lipids and discuss their involvement in plant responses to abiotic stress. As such, this review provides crucial background for further research on the interactions between plant lipids and abiotic stress.

Therapeutic Potential of Plant Oxylipins

For immobile plants, the main means of protection against adverse environmental factors is the biosynthesis of various secondary (specialized) metabolites. The extreme diversity and high biological activity of these metabolites determine the researchers' interest in plants as a source of therapeutic agents. Oxylipins, oxygenated derivatives of fatty acids, are particularly promising in this regard. Plant oxylipins, which are characterized by a diversity of chemical structures, can exert protective and therapeutic properties in animal cells. While the therapeutic potential of some classes of plant oxylipins, such as jasmonates and acetylenic oxylipins, has been analyzed thoroughly, other oxylipins are barely studied in this regard. Here, we present a comprehensive overview of the therapeutic potential of all major classes of plant oxylipins, including derivatives of acetylenic fatty acids, jasmonates, six- and nine-carbon aldehydes, oxy-, epoxy-, and hydroxy-derivatives of fatty acids, as well as spontaneously formed phytoprostanes and phytofurans. The presented analysis will provide an impetus for further research investigating the beneficial properties of these secondary metabolites and bringing them closer to practical applications.

Paraoxonase 1 hydrolysis of EPA-derived lactone impairs endothelial-mediated vasodilation

Human serum paraoxonase-1 (PON1) is a lactonase that plays a significant role in anti-atherosclerotic high-density lipoprotein (HDL) activity. PON1 is also localized in endothelial cell membranes, where it is enzymatically active and regulates endothelial signals. PON1 has a high specificity for lipophilic lactones and has been shown to hydrolyze and regulate lactone lipid mediators derived from arachidonic polyunsaturated fatty acids (PUFA). Previously, we showed that an arachidonic acid lactone metabolite (AA-L) dose-dependently dilates PON1 gene deletion (PON1KO) mouse mesenteric arteries significantly more than wild-type arteries. In contrast, preincubation with HDL or rePON1 reduced AA-L-dependent vasodilation. Recently we showed that an additional δ-lactone metabolite derived from the eicosapentaenoic acid lactone, 5,6-δ-DiHETE lactone (EPA-L) reduced blood pressure by dilating microvessels of hypertensive rats. However, whether PON1 regulates the activity of the EPA-L lipid mediator is unknown.

AIM

To demonstrate that PON1 hydrolyzes EPA-L and to reveal the effect of this hydrolysis on endothelial-dependent vascular dilation.

METHODS AND RESULTS

In vascular reactivity experiments, EPA-L dose-dependently dilated PON1KO mouse mesenteric arteries significantly more than wild-type mesenteric arteries. This dilation was not affected by nitric oxide inhibition. PON1 impaired the cellular calcium increase mediated by EPA-L in endothelial cells, though this impairment decreased with PON1 internalization to the cell.

CONCLUSION

These findings support that PUFA-lactones are physiological substrates of PON1, and that PON1 activity in the endothelial membrane affects the dilation of microvessels that is induced by these endothelial-derived hyperpolarizing PUFA-lactones.

Fishing for lipid lactones using selective reaction and characteristic fragmentation pattern

Extensive research has been invested in developing sensitive methods to identify lipid mediators (LMs) from multiple biological matrices. Previous studies point to the existence of a potential family of lactone-containing metabolites generated from eicosanoid families, isoprostanes, and prostanoid-like compounds that may function as LMs. However, targeted lipidomic studies do not routinely include lactone-containing lipids due to their low ionizability and instability under some common sample preparation conditions. Thus, the discovery of lactone-containing LM is limited. Herein we describe a method for selective identification of lipid lactones from within biological matrices. This method is based on a selective reaction of lactones with 1-(3-aminopropyl)imidazole, followed by cation exchange solid phase extraction and the identification of characteristic fragmentation patterns unique to reaction products of lactones in LC/MS/MS. NMR and LC/MS results indicated that saturated and unsaturated aliphatic ɣ and δ lactone model compounds mixed with human serum were successfully detected. MS/MS analyses of the reaction products revealed a unique pattern for the lactones, resulting from common neutral losses and fragmentation. When applied to esters and free fatty acids, some reaction products were observed. However, these reaction products' MS/MS fragmentation did not match the specific fragmentation of the lactones' reaction products. Confirming that lactones can be detected in a highly selective manner from within complex biological matrices when using the presented method. Thus, the presented method can selectively analyze lactones and may further complement existing lipidomic approaches to discover new LMs.

Bioavailable phytoprostanes and phytofurans from Gracilaria longissima have anti-inflammatory effects in endothelial cells

BACKGROUND

An array of bioactive compounds with health-promoting effects has been described in several species of macroalgae. Among them, phytoprostanes (PhytoPs) and phytofurans (PhytoFs), both autoxidation products of α-linolenic acid, have been seen to exert immunomodulatory and antiinflammatory activities in vitro. The purpose of this study was to explore the bioaccesibility, bioavailability, and bioactivity of PhytoPs and PhytoFs obtained from the edible red algae Gracilaria longissima, and to gain insight into the anti-inflammatory activity of their bioavailable fraction in human endothelial cells.

METHODS

The PhytoPs and PhytoFs profile and concentration of G. longissima were determined by UHPLC-QqQ-MS/MS. Algal samples were processed following a standardised digestion method including gastric, intestinal, and gastrointestinal digestion. The bioavailability of the PhytoPs and PhytoFs in the characterized fractions was assessed in a Caco-2 cell monolayer model of the intestinal barrier. The inflammation response of these prostaglandin-like compounds in human endothelial cells, after intestinal absorption, was investigated in vitro.

RESULTS

Simulated digestions significantly reduced the concentration of PhytoPs and PhytoFs up to 1.17 and 0.42 μg per 100 g, respectively, on average, although permeability through the Caco-2 cell monolayer was high (up to 88.2 and 97.7%, on average, respectively). PhytoP and PhytoF-enriched extracts of raw algae impaired the expression of ICAM-1 and IL-6 inflammation markers. The inflammation markers progressed in contrast to the relative concentrations of bioactive oxylipins, suggesting pro- or anti-inflammatory activity on their part. In this aspect, the cross-reactivity of these compounds with diverse receptors, and their relative concentration could explain the diversity of the effects found in the current study.

CONCLUSIONS

The results indicate that PhytoPs and PhytoFs display complex pharmacological profiles probably mediated through their different actions and affinities in the endothelium.

Phytoprostanes and Phytofurans-Oxidative Stress and Bioactive Compounds-in Almonds are Affected by Deficit Irrigation in Almond Trees

Almonds have gained consumers' attention due to their health benefits (they are rich in bioactive compounds) and sensory properties. Nevertheless, information about phytoprostanes (PhytoPs) and phytofurans (PhytoFs) (new plant markers of oxidative stress and compounds with biological properties for human health) in almonds under deficit irrigation is scarce or does not exist. These compounds are plant oxylipins synthesized by the oxidation of α-linolenic acid (ALA). Besides, they are biomarkers of plant oxidative degradation and biologically active molecules involved in several plant defense mechanisms. hydroSOStainable or hydroSOS mean plant foods made from from plants under controlled water stress. Almonds are a good source of polyunsaturated fatty (PUFAs) acids, including a high content of ALA. This paper aimed to describe the influence of diverse irrigation treatments on in vitro anti-oxidant activity (AAc) and total phenolic content (TPC), as well as on the level of ALA, PhytoP, and PhytoF in "Vairo" almonds. The AAc and TPC were not affected by the irrigation strategy, while the in vivo oxidative stress makers, PhytoPs and PhytoFs, exhibited significant differences in response to water shortage. The total PhytoP and PhytoF contents ranged from 4551 to 8151 ng/100 g dry weight (dw) and from 33 to 56 ng/100 g dw, respectively. The PhytoP and PhytoF profiles identified in almonds showed significant differences among treatments. Individual PhytoPs and PhytoFs were present above the limit of detection only in almonds obtained from trees maintained under deficit irrigation (DI) conditions (regulated deficit irrigation, RDI, and sustained deficit irrigation, SDI) but not in control almonds obtained from fully irrigated trees. Therefore, these results confirm PhytoPs and PhytoFs as valuable biomarkers to detect whether an almond-based product is hydroSOStainable. As a final conclusion, it can be stated that almond quality and functionality can be improved and water irrigation consumption can be reduced if controlled DI strategies are applied in almond orchards.

Optimization of Free Phytoprostane and Phytofuran Production by Enzymatic Hydrolysis of Pea Extracts Using Esterases

Given the growing interest in phytoprostanes (PhytoPs) and phytofurans (PhytoFs) in the fields of plant physiology, biotechnology, and biological function, the present study aims to optimize a method of enzymatic hydrolysis that utilizes bacterial and yeast esterases that allow the appropriate quantification of PhytoPs and PhytoFs. To obtain the highest concentration of PhytoPs and PhytoFs, a response surface methodology/Box-Behnken design was used to optimize the hydrolysis conditions. Based on the information available in the literature on the most critical parameters that influence the activity of esterases, the three variables selected for the study were temperature (°C), time (min), and enzyme concentration (%). The optimal hydrolysis conditions retrieved differed between PhytoPs (21.5 °C, 5.7 min, and 0.61 μg of enzyme per reaction) and PhytoFs (20.0 °C, 5.0 min, and 2.17 μg of enzyme per reaction) and provided up to 25.1- and 1.7-fold higher contents relative to nonhydrolyzed extracts. The models were validated by comparing theoretical and experimental values for PhytoP and PhytoF yields (1.01 and 1.06 theoretical/experimental rates, respectively). The optimal conditions were evaluated for their relative influence on the yield of individual nonesterified PhytoPs and PhytoFs to define the limitations of the models for obtaining the highest concentration of most considered compounds. In conclusion, the models developed provided valuable alternatives to the currently applied methods using unspecific alkaline hydrolysis to obtain free nonesterified PhytoPs and PhytoFs, which give rise to more specific hydrolysis of PhytoP and PhytoF esters, reducing the degradation of free compounds by classical chemical procedures.

Oxidized Products of α-Linolenic Acid Negatively Regulate Cellular Survival and Motility of Breast Cancer Cells

Despite recent advances in our understanding of the biological processes leading to the development and progression of cancer, there is still a need for new and effective agents to treat this disease. Phytoprostanes (PhytoPs) and phytofurans (PhytoFs) are non-enzymatically oxidized products of α-linolenic acid that are present in seeds and vegetable oils. They have been shown to possess anti-inflammatory and apoptosis-promoting activities in macrophages and leukemia cells, respectively. In this work, seven PhytoPs (PP1–PP7) and one PhytoFs (PF1) were evaluated for their cytotoxic, chemosensitization, and anti-migratory activities using the MCF-7 and MDA-MB-231 breast cancer cell lines. Among the tested compounds, only three PhytoPs had a significant effect on cell viability compared to the control group: Ent-9-L₁-PhytoP (PP6) decreased cell viability in both cell lines, while 16-F_1t-PhytoP (PP1) and 9-L₁-PhytoP (PP5) decreased viability of MCF-7 and MDA-MB-231 cells, respectively. When combined with a sub-cytotoxic dose of doxorubicin, these three PhytoPs displayed significantly enhanced cytotoxic effects on MCF-7 cells while the chemotherapeutic drug alone had no effect. In cellular motility assays, Ent-9-(RS)-12-epi-ST-Δ¹⁰-13-PhytoF could significantly inhibit cellular migration of MDA-MB-231 cells. In addition, Ent-9-(RS)-12-epi-ST-Δ¹⁰-13-PhytoF also enhanced cellular adhesion of MDA-MB-231 cells.

Lipid Mediators From Timothy Grass Pollen Contribute to the Effector Phase of Allergy and Prime Dendritic Cells for Glycolipid Presentation

Plant pollen are an important source of antigens that evoke allergic responses. Protein antigens have been the focus of studies aiming to elucidate the mechanisms responsible for allergic reactions to pollen. However, proteins are not the sole active agent present in pollen. It is known that pollen grains contain lipids essential for its reproduction and bioactive lipid mediators. These small molecular compounds are co-delivered with the allergens and hence have the potential to modulate the immune response of subjects by activating their innate immune cells. Previous reports showed that pollen associated lipid mediators exhibited neutrophil- and eosinophil-chemotactic activity and induced polarization of dendritic cells (DCs) toward a Th2-inducing phenotype. In our study we performed chemical analyses of the pollen associated lipids, that are rapidly released upon hydration. As main components we have identified different types of phytoprostanes (PhytoPs), and for the first time phytofurans (PhytoFs), with predominating 16-F_1t-PhytoPs (PPF₁-I), 9-F_1t-PhytoPs (PPF₁-II), 16-E_1t-PhytoPs (PPE₁-I) and 9-D_1t-PhytoPs (PPE₁-II), and 16(RS)-9-epi-ST-Δ¹⁴-10-PhytoFs. Interestingly 16-E_1t-PhytoP and 9-D_1t-PhytoPs were found to be bound to glycerol. Lipid-containing samples (aqueous pollen extract, APE) induced murine mast cell chemotaxis and IL-6 release, and enhanced their IgE-dependent degranulation, demonstrating a role for these lipids in the immediate effector phase of allergic inflammation. Noteworthy, mast cell degranulation seems to be dependent on glycerol-bound, but not free phytoprostanes. On murine dendritic cells, APE selectively induced the upregulation of CD1d, likely preparing lipid-antigen presentation to iNKT cells. Our report contributes to the understanding of the activity of lipid mediators in the immediate effector phase of allergic reactions but identifies a yet undescribed pathway for the recognition of pollen-derived glycolipids by iNKT cells.

Potential of Physalis peruviana calyces as a low-cost valuable resource of phytoprostanes and phenolic compounds

BACKGROUND

In Colombia, agro-industrial residues represent an enormous economic and environmental problem, which could be reduced if different techniques for the addition of value to such residues were implemented by this industrial sector. One of the fruits with the highest export rates is Physalis peruviana (goldenberry); however, this fruit is generally marketed without its calyx, generating a large amount of residues. To develop a strategy to add value to these residues, it is essential to know their chemical composition.

RESULTS

In the present work, phytoprostanes (PhytoPs) - new active oxylipins - have been detected for the first time in Physalis peruviana calyces by ultra-high performance liquid chromatography triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS), F_1t -phytoprostanes and D_1t -phytoprostanes being the predominant and minor classes, respectively. In addition, we were able to characterize the phenolic compounds profile of this matrix using LC-IT-DAD-MS/MS, describing six phenolic derivatives for the first time therein.

CONCLUSIONS

This study increases our knowledge of the chemical composition of the calyces of this fruit and thereby supports the recycling of this class of residue. Consequently, goldenberry calyces could be used as phytotherapeutic, nutraceutic, or cosmetic ingredients for the development of diverse natural products. © 2018 Society of Chemical Industry.

Pollen Lipids Can Play a Role in Allergic Airway Inflammation

In seed plants, pollen grains carry the male gametes to female structures. They are frequent in the ambient air, and cause airway inflammation in one out of four persons in the population. This was traditionally attributed to soluble glycoproteins, leaking into the nasal mucosa or the conjunctiva, and able to bind antibodies. It is now more and more recognized that also other immunomodulating compounds are present. Lipids bind to Toll-like and PPARγ receptors belonging to antigen-presenting cells in the mammal immune system, activate invariant Natural Killer T-cells, and are able to induce a Type 2 reaction in effector cells. They may also mimic lipid mediators from mammal mast cells. Pollen grains have a rich lipodome of their own. Among the lipids that have been associated with an atopic reaction are saturated and unsaturated fatty acids, glycophospholipids, sphingolipids, sterols, and oxylipids, as well as lipopolysaccharides from the microbiome on the pollen surface. Lipids can be ligands to allergenic proteins.

Priming plant resistance by activation of redox-sensitive genes

Priming by natural compounds is an interesting alternative for sustainable agriculture, which also contributes to explore the molecular mechanisms associated with stress tolerance. Although hosts and stress types eventually determine the mode of action of plant-priming agents, it highlights that many of them act on redox signalling. These include vitamins thiamine, riboflavin and quercetin; organic acids like pipecolic, azelaic and hexanoic; volatile organic compounds such as methyl jasmonate; cell wall components like chitosans and oligogalacturonides; H₂O₂, etc. This review provides data on how priming inducers promote stronger and faster responses to stress by modulating the oxidative environment, and interacting with signalling pathways mediated by salycilic acid, jasmonic acid and ethylene. The histone modifications involved in priming that affect the transcription of defence-related genes are also discussed. Despite the evolutionary distance between plants and animals, and the fact that the plant innate immunity takes place in each plant cell, they show many similarities in the molecular mechanisms that underlie pathogen perception and further signalling to activate defence responses. This review highlights the similarities between priming through redox signalling in plants and in mammalian cells. The strategies used by pathogens to manipulate the host´s recognition and the further activation of defences also show similarities in both kingdoms. Moreover, phytochemicals like sulforaphane and 12-oxo-phytodienoic acid prime both plant and mammalian responses by activating redox-sensitive genes. Hence research data into the priming of plant defences can provide additional information and a new viewpoint for priming mammalian defence, and vice versa.

Total syntheses of all tri-oxygenated 16-phytoprostane classes via a common precursor constructed by oxidative cyclization and alkyl-alkyl coupling reactions as the key steps

A unified strategy for the total synthesis of the methyl esters of all phytoprostane (PhytoP) classes bearing two ring-oxygen atoms based on an orthogonally protected common precursor is described. Racemic 16-F_1t-, 16-E₁-PhytoP and their C-16 epimers, which also occur as racemates in Nature, were successfully obtained. The first total synthesis of very sensitive 16-D_1t-PhytoP succeeded, however, it quickly isomerized to more stable, but so far also unknown Δ¹³-16-D_1t-PhytoP, which may serve as a more reliable biomarker for D-type PhytoP. The dioxygenated cyclopentane ring carrying the ω-chain with the oxygen functionality in the 16-position was approached by a radical oxidative cyclization mediated by ferrocenium hexafluorophosphate and TEMPO. The α-chain was introduced by a new copper-catalyzed alkyl-alkyl coupling of a 6-heptenyl Grignard reagent with a functionalized cyclopentylmethyl triflate.

Lipid signalling in plant responses to abiotic stress

Lipids are one of the major components of biological membranes including the plasma membrane, which is the interface between the cell and the environment. It has become clear that membrane lipids also serve as substrates for the generation of numerous signalling lipids such as phosphatidic acid, phosphoinositides, sphingolipids, lysophospholipids, oxylipins, N-acylethanolamines, free fatty acids and others. The enzymatic production and metabolism of these signalling molecules are tightly regulated and can rapidly be activated upon abiotic stress signals. Abiotic stress like water deficit and temperature stress triggers lipid-dependent signalling cascades, which control the expression of gene clusters and activate plant adaptation processes. Signalling lipids are able to recruit protein targets transiently to the membrane and thus affect conformation and activity of intracellular proteins and metabolites. In plants, knowledge is still scarce of lipid signalling targets and their physiological consequences. This review focuses on the generation of signalling lipids and their involvement in response to abiotic stress. We describe lipid-binding proteins in the context of changing environmental conditions and compare different approaches to determine lipid-protein interactions, crucial for deciphering the signalling cascades.

Biologically Active Oxylipins from Enzymatic and Nonenzymatic Routes in Macroalgae

Marine algae are rich and heterogeneous sources of great chemical diversity, among which oxylipins are a well-recognized class of natural products. Algal oxylipins comprise an assortment of oxygenated, halogenated, and unsaturated functional groups and also several carbocycles, varying in ring size and position in lipid chain. Besides the discovery of structurally diverse oxylipins in macroalgae, research has recently deciphered the role of some of these metabolites in the defense and innate immunity of photosynthetic marine organisms. This review is an attempt to comprehensively cover the available literature on the chemistry, biosynthesis, ecology, and potential bioactivity of oxylipins from marine macroalgae. For a better understanding, enzymatic and nonenzymatic routes were separated; however, both processes often occur concomitantly and may influence each other, even producing structurally related molecules.

Oxidation-sensitive nociception involved in endometriosis-associated pain

Endometriosis is a disease characterized by the growth of endometrial tissue outside the uterus and is associated with chronic pelvic pain. Peritoneal fluid (PF) of women with endometriosis is a dynamic milieu and is rich in inflammatory markers, pain-inducing prostaglandins prostaglandin E2 and prostaglandin F2α, and lipid peroxides; and the endometriotic tissue is innervated with nociceptors. Our clinical study showed that the abundance of oxidatively modified lipoproteins in the PF of women with endometriosis and the ability of antioxidant supplementation to alleviate endometriosis-associated pain. We hypothesized that oxidatively modified lipoproteins present in the PF are the major source of nociceptive molecules that play a key role in endometriosis-associated pain. In this study, PF obtained from women with endometriosis or control women were used for (1) the detection of lipoprotein-derived oxidation-sensitive pain molecules, (2) the ability of such molecules to induce nociception, and (3) the ability of antioxidants to suppress this nociception. LC-MS/MS showed the generation of eicosanoids by oxidized-lipoproteins to be similar to that seen in the PF. Oxidatively modified lipoproteins induced hypothermia (intracerebroventricular) in CD-1 mice and nociception in the Hargreaves paw withdrawal latency assay in Sprague-Dawley rats. Antioxidants, vitamin E and N-acetylcysteine, and the nonsteroidal anti-inflammatory drug indomethacin suppressed the pain-inducing ability of oxidatively modified lipoproteins. Treatment of human endometrial cells with oxidatively modified lipoproteins or PF from women with endometriosis showed upregulation of similar genes belonging to opioid and inflammatory pathways. Our finding that oxidatively modified lipoproteins can induce nociception has a broader impact not only on the treatment of endometriosis-associated pain but also on other diseases associated with chronic pain.

Dependency of Phytoprostane Fingerprints of Must and Wine on Viticulture and Enological Processes

Wine is one of the most consumed alcoholic beverages around the world. Red wine has demonstrated several benefits for health maintenance. One group of potential anti-inflammatory compounds is the phytoprostanes, oxidative degradation products of linolenic acid. The aim of the present study was to measure, for the first time, the phytoprostane content in wine and must by an UHPLC-QqQ-MS/MS method after solid-phase extraction. The data showed two predominant classes of phytoprostanes: F1- and D1-phytoprostane series. In wines, the total phytoprostane concentration ranged from 134.1 ± 2.3 to 216.2 ± 3.06 ng/mL. Musts showed concentrations between 21.4 ± 0.8 and 447.1 ± 15.8 ng/mL. The vinification and aging procedures for the production of wine seem to influence the final phytoprostane levels in red wine and to modify the phytoprostane profile. The high concentrations observed and previous reports on anti-inflammatory effects of phytoprostanes make further research on the benefits of phytoprostanes more important.

Green Leaf Volatile Emissions during High Temperature and Drought Stress in a Central Amazon Rainforest

Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. In this study, we present observations of green leaf volatile (GLV) emissions during membrane peroxidation processes associated with the combined effects of high leaf temperatures and drought-induced leaf senescence from individual detached leaves and a rainforest ecosystem in the central Amazon. Temperature-dependent leaf emissions of volatile terpenoids were observed during the morning, and together with transpiration and net photosynthesis, showed a post-midday depression. This post-midday depression was associated with a stimulation of C₅ and C₆ GLV emissions, which continued to increase throughout the late afternoon in a temperature-independent fashion. During the 2010 drought in the Amazon Basin, which resulted in widespread tree mortality, green leaf volatile emissions (C₆ GLVs) were observed to build up within the forest canopy atmosphere, likely associated with high leaf temperatures and enhanced drought-induced leaf senescence processes. The results suggest that observations of GLVs in the tropical boundary layer could be used as a chemical sensor of reduced ecosystem productivity associated with drought stress.

Nonenzymatic α-Linolenic Acid Derivatives from the Sea: Macroalgae as Novel Sources of Phytoprostanes

Phytoprostanes, autoxidation products of α-linolenic acid, have been studied in several plant species, but information regarding the natural occurrence of this large family of biologically active oxidized lipids in macroalgae is still scarce. In this work, the free phytoprostane composition of 24 macroalgae species belonging to Chlorophyta, Phaeophyta, and Rhodophyta was determined through a recently validated UHPLC-QqQ-MS/MS method. The phytoprostane profiles varied greatly among all samples, F1t-phytoprostanes and L1-phytoprostanes being the predominant and minor classes, respectively. No correlation between the amounts of α-linolenic acid in alga material and phytoprostane content was found. Therefore, it was hypothesized that the observed variability could be species-specific or result from interspecific interactions. This study provides new insight about the occurrence of phytoprostanes in macroalgae and opens doors for future exploitation of these marine photosynthetic organisms as sources of potentially bioactive oxylipins, encouraging their incorporation in food products and nutraceutical and pharmaceutical preparations for human health.

Facile synthesis of cyclopentenone B1- and L1-type phytoprostanes

Phytoprostanes (PhytoPs) represent non-enzymatic metabolites of α-linolenic acid (ALA), the essential omega-3 polyunsaturated fatty acid (PUFA) derived from plants. PhytoPs are present in the plant kingdom and represent endogenous mediators capable of protecting cells from oxidative stress damages in plants. Recently, it was found that such metabolites are present in cooking oil in high quantities, and also that B₁-PhytoPs protect immature neurons from oxidant injury and promote differentiation of oligodendrocyte progenitors through PPAR-γ activation. We report a novel and facile synthesis of natural 2,3-substituted cyclopentenone PhytoPs, 16-B₁-PhytoP, and 9-L₁-PhytoP. Our strategy is based on reductive alkylation at the 2-position of 1,3-cyclopentanedione using a recent protocol developed by Ramachary et al. and on a cross-coupling metathesis to access conjugate dienone system. In conclusion, this strategy permitted access to B₁- and L_1-PhytoPs in a relative short sequence process, and afford the possibility to easily develop analogs of PhytoPs.

Water deficit during pit hardening enhances phytoprostanes content, a plant biomarker of oxidative stress, in extra virgin olive oil

No previous information exists on the effects of water deficit on the phytoprostanes (PhytoPs) content in extra virgin olive oil from fruits of mature olive (Olea europaea L. cv. Cornicabra) trees during pit hardening. PhytoPs profile in extra virgin olive oil was characterized by the presence of 9-F1t-PhytoP, 9-epi-9-F1t-PhytoP, 9-epi-9-D1t-PhytoP, 9-D1t-PhytoP, 16-B1-PhytoP + ent-16-B1-PhytoP, and 9-L1-PhytoP + ent-9-L1-PhytoP. The qualitative and quantitative differences in PhytoPs content with respect to those reported by other authors indicate a decisive effect of cultivar, oil extraction technology, and/or storage conditions prone to autoxidation. The pit hardening period was critical for extra virgin olive oil composition because water deficit enhanced the PhytoPs content, with the concomitant potential beneficial aspects on human health. From a physiological and agronomical point of view, 9-F1t-PhytoP, 9-epi-9-F1t-PhytoP, and 16-B1-PhytoP + ent-16-B1-PhytoP could be considered as early candidate biomarkers of water stress in olive tree.

Oxylipins and plant abiotic stress resistance

Oxylipins are signaling molecules formed enzymatically or spontaneously from unsaturated fatty acids in all aerobic organisms. Oxylipins regulate growth, development, and responses to environmental stimuli of organisms. The oxylipin biosynthesis pathway in plants includes a few parallel branches named after first enzyme of the corresponding branch as allene oxide synthase, hydroperoxide lyase, divinyl ether synthase, peroxygenase, epoxy alcohol synthase, and others in which various biologically active metabolites are produced. Oxylipins can be formed non-enzymatically as a result of oxygenation of fatty acids by free radicals and reactive oxygen species. Spontaneously formed oxylipins are called phytoprostanes. The role of oxylipins in biotic stress responses has been described in many published works. The role of oxylipins in plant adaptation to abiotic stress conditions is less studied; there is also obvious lack of available data compilation and analysis in this area of research. In this work we analyze data on oxylipins functions in plant adaptation to abiotic stress conditions, such as wounding, suboptimal light and temperature, dehydration and osmotic stress, and effects of ozone and heavy metals. Modern research articles elucidating the molecular mechanisms of oxylipins action by the methods of biochemistry, molecular biology, and genetics are reviewed here. Data on the role of oxylipins in stress signal transduction, stress-inducible gene expression regulation, and interaction of these metabolites with other signal transduction pathways in cells are described. In this review the general oxylipin-mediated mechanisms that help plants to adjust to a broad spectrum of stress factors are considered, followed by analysis of more specific responses regulated by oxylipins only under certain stress conditions. New approaches to improvement of plant resistance to abiotic stresses based on the induction of oxylipin-mediated processes are discussed.

Phytoprostanes in almonds: identification, quantification, and impact of cultivar and type of cultivation

The phytoprostane profile in 11 almonds cvs varied greatly according to the genotype and several factors (agricultural system conventional or ecological and irrigation).

Involvement of the electrophilic isothiocyanate sulforaphane in Arabidopsis local defense responses

Plants defend themselves against microbial pathogens through a range of highly sophisticated and integrated molecular systems. Recognition of pathogen-secreted effector proteins often triggers the hypersensitive response (HR), a complex multicellular defense reaction where programmed cell death of cells surrounding the primary site of infection is a prominent feature. Even though the HR was described almost a century ago, cell-to-cell factors acting at the local level generating the full defense reaction have remained obscure. In this study, we sought to identify diffusible molecules produced during the HR that could induce cell death in naive tissue. We found that 4-methylsulfinylbutyl isothiocyanate (sulforaphane) is released by Arabidopsis (Arabidopsis thaliana) leaf tissue undergoing the HR and that this compound induces cell death as well as primes defense in naive tissue. Two different mutants impaired in the pathogen-induced accumulation of sulforaphane displayed attenuated programmed cell death upon bacterial and oomycete effector recognition as well as decreased resistance to several isolates of the plant pathogen Hyaloperonospora arabidopsidis. Treatment with sulforaphane provided protection against a virulent H. arabidopsidis isolate. Glucosinolate breakdown products are recognized as antifeeding compounds toward insects and recently also as intracellular signaling and bacteriostatic molecules in Arabidopsis. The data presented here indicate that these compounds also trigger local defense responses in Arabidopsis tissue.

Synthesis and discovery of phytofurans: metabolites of α-linolenic acid peroxidation

Novel phytofurans, metabolites of α-linolenic acid preoxidation are synthesized and used to identified and quantified them in seeds and nuts for the first time.

Toxicity of Fatty Acid autoxidation products: highest anti-microbial toxicity in the initial oxidative phase

The autoxidation-degradation processes of polyunsaturated fatty acids give rise to toxic products, and the relative toxicity at different stages of the process is of great interest. We report here that when methyl α-linolenate is exposed to sunlight and air, its antimicrobial activity against yeasts and bacteria (as measured by agar diffusion) reaches its maximum during the early oxidative phase when addition of oxygen occurs and the mass increases drastically. Before exposure, the activity is minimal or zero, but it increases rapidly during the first days of the test, simultaneously with the increase of the mass of the material, and begins to decrease while the mass is still increasing and before the mass begins to decrease due to degradation and formation of volatile compounds. Thus, the products formed during the degradation phase of the process are far less toxic to the test organisms than the compounds formed at the early stages when addition of oxygen occurs with maximal rate.

Nonenzymatic oxygenated metabolites of α-linolenic acid B1- and L1-phytoprostanes protect immature neurons from oxidant injury and promote differentiation of oligodendrocyte progenitors through PPAR-γ activation

Phytoprostanes (PhytoP's) are formed in higher plants from α-linolenic acid via a nonenzymatic free radical-catalyzed pathway and act as endogenous mediators capable of protecting cells from damage under various conditions related to oxidative stress. Humans are exposed to PhytoP's, as they are present in relevant quantities in vegetable food and pollen. The uptake of PhytoP's through the olfactory epithelium of the nasal mucosa, upon pollen grain inhalation, is of interest as the intranasal pathway is regarded as a direct route of communication between the environment and the brain. On this basis, we sought to investigate the potential activities of PhytoP's on immature cells of the central nervous system, which are particularly susceptible to oxidative stress. In neuroblastoma SH-SY5Y cells, used as a model for undifferentiated neurons, B1-PhytoP's, but not F1-PhytoP's, increased cell metabolic activity and protected them from oxidant damage caused by H2O2. Moreover, B1-PhytoP's induced a moderate depolarization of the mitochondrial inner membrane potential. These effects were prevented by the PPAR-γ antagonist GW9662. When SH-SY5Y cells were induced to differentiate toward a more mature phenotype, they became resistant to B1-PhytoP activities. B1-PhytoP's also influenced immature cells of an oligodendroglial line, as they increased the metabolic activity of oligodendrocyte progenitors and strongly accelerated their differentiation to immature oligodendrocytes, through mechanisms at least partially dependent on PPAR-γ activity. However, B1-PhytoP's did not protect oligodendrocyte progenitors against oxidant injury. Taken together, these data suggest that B1-PhytoP's, through novel mechanisms involving PPAR-γ, can specifically affect immature brain cells, such as neuroblasts and oligodendrocyte progenitors, thereby conferring neuroprotection against oxidant injury and promoting myelination.

Bidirectional exchange of biogenic volatiles with vegetation: emission sources, reactions, breakdown and deposition

Biogenic volatile organic compound (BVOC) emissions are widely modelled as inputs to atmospheric chemistry simulations. However, BVOC may interact with cellular structures and neighbouring leaves in a complex manner during volatile diffusion from the sites of release to leaf boundary layer and during turbulent transport to the atmospheric boundary layer. Furthermore, recent observations demonstrate that the BVOC emissions are bidirectional, and uptake and deposition of BVOC and their oxidation products are the rule rather than the exception. This review summarizes current knowledge of within-leaf reactions of synthesized volatiles with reactive oxygen species (ROS), uptake, deposition and storage of volatiles, and their oxidation products as driven by adsorption on leaf surface and solubilization and enzymatic detoxification inside leaves. The available evidence indicates that because of the reactions with ROS and enzymatic metabolism, the BVOC gross production rates are much larger than previously thought. The degree to which volatiles react within leaves and can be potentially taken up by vegetation depends upon compound reactivity, physicochemical characteristics, as well as upon their participation in leaf metabolism. We argue that future models should be based upon the concept of bidirectional BVOC exchange and consider modification of BVOC sink/source strengths by within-leaf metabolism and storage.

The Nicotiana attenuata GLA1 lipase controls the accumulation of Phytophthora parasitica-induced oxylipins and defensive secondary metabolites

Nicotiana attenuata plants silenced in the expression of GLYCEROLIPASE A1 (ir-gla1 plants) are compromised in the herbivore- and wound-induced accumulation of jasmonic acid (JA). However, these plants accumulate wild-type (WT) levels of JA and divinyl-ethers during Phytophthora parasitica infection. By profiling oxylipin-enriched fractions with targeted and untargeted liquid chromatography-tandem time-of-flight mass spectrometry approaches, we demonstrate that the accumulation of 9-hydroxy-10E,12Z-octadecadienoic acid (9-OH-18:2) and additional C18 and C19 oxylipins is reduced by ca. 20-fold in P. parasitica-infected ir-gla1 leaves compared with WT. This reduced accumulation of oxylipins was accompanied by a reduced accumulation of unsaturated free fatty acids and specific lysolipid species. Untargeted metabolic profiling of total leaf extracts showed that 87 metabolites accumulated differentially in leaves of P. parasitica-infected ir-gla1 plants with glycerolipids, hydroxylated-diterpene glycosides and phenylpropanoid derivatives accounting together for ca. 20% of these 87 metabolites. Thus, P. parasitica-induced oxylipins may participate in the regulation of metabolic changes during infection. Together, the results demonstrate that GLA1 plays a distinct role in the production of oxylipins during biotic stress responses, supplying substrates for 9-OH-18:2 and additional C18 and C19 oxylipin formation during P. parasitica infection, whereas supplying substrates for the biogenesis of JA during herbivory and mechanical wounding.

Non-enzymatic lipid oxidation products in biological systems: assessment of the metabolites from polyunsaturated fatty acids

Metabolites of non-enzymatic lipid peroxidation of polyunsaturated fatty acids notably omega-3 and omega-6 fatty acids have become important biomarkers of lipid products. Especially the arachidonic acid-derived F2-isoprostanes are the classic in vivo biomarker for oxidative stress in biological systems. In recent years other isoprostanes from eicosapentaenoic, docosahexaenoic, adrenic and α-linolenic acids have been evaluated, namely F3-isoprostanes, F4-neuroprostanes, F2-dihomo-isoprostanes and F1-phytoprostanes, respectively. These have been gaining interest as complementary specific biomarkers in human diseases. Refined extraction methods, robust analysis and elucidation of chemical structures have improved the sensitivity of detection in biological tissues and fluids. Previously the main reliable instrumentation for measurement was gas chromatography-mass spectrometry (GC-MS), but now the use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and immunological techniques is gaining much attention. In this review, the types of prostanoids generated from non-enzymatic lipid peroxidation of some important omega-3 and omega-6 fatty acids and biological samples that have been determined by GC-MS and LC-MS/MS are discussed.

A mutation in the expansin-like A2 gene enhances resistance to necrotrophic fungi and hypersensitivity to abiotic stress in Arabidopsis thaliana

Expansins are cell wall loosening agents, known for their endogenous function in cell wall extensibility. The Arabidopsis expansin-like A2 (EXLA2) gene was identified by its down-regulation in response to infection by the necrotrophic pathogen Botrytis cinerea, and by the reduced susceptibility of an exla2 mutant to the same pathogen. The exla2 mutant was equally susceptible to Pseudomonas syringae pv. tomato, but was more resistant to the necrotrophic fungus Alternaria brassicicola, when compared with the wild-type or with transgenic, ectopic EXLA2-overexpressing lines. The exla2 mutants also enhanced tolerance to the phytoprostane-A1 . This suggests that the absence or down-regulation of EXLA2 leads to increased resistance to B. cinerea in a CORONATINE INSENSITIVE 1 (COI1)-dependent manner, and this down-regulation can be achieved by phytoprostane-A1 treatment. EXLA2 is induced significantly by salinity and cold, and by the exogenous application of abscisic acid. The exla2 mutant also showed hypersensitivity towards increased salt and cold, and this hypersensitivity required a functional abscisic acid pathway. The differential temporal expression of EXLA2 and the phenotypes in transgenic plants with altered expression of EXLA2 indicate that plant cell wall structure is an important player during Arabidopsis developmental stages. Our results indicate that EXLA2 appears to be important in response to various biotic and abiotic stresses, particularly in the pathogenesis of necrotrophic pathogens and in the tolerance to abiotic stress.

Increasing atmospheric CO2 reduces metabolic and physiological differences between isoprene- and non-isoprene-emitting poplars

Isoprene, a volatile organic compound produced by some plant species, enhances abiotic stress tolerance under current atmospheric CO2 concentrations, but its biosynthesis is negatively correlated with CO2 concentrations. We hypothesized that losing the capacity to produce isoprene would require stronger up-regulation of other stress tolerance mechanisms at low CO2 than at higher CO2 concentrations. We compared metabolite profiles and physiological performance in poplars (Populus × canescens) with either wild-type or RNAi-suppressed isoprene emission capacity grown at pre-industrial low, current atmospheric, and future high CO2 concentrations (190, 390 and 590 ppm CO2 , respectively). Suppression of isoprene biosynthesis led to significant rearrangement of the leaf metabolome, increasing stress tolerance responses such as xanthophyll cycle pigment de-epoxidation and antioxidant levels, as well as altering lipid, carbon and nitrogen metabolism. Metabolic and physiological differences between isoprene-emitting and suppressed lines diminished as growth CO2 concentrations rose. The CO2 dependence of our results indicates that the effects of isoprene biosynthesis are strongest at pre-industrial CO2 concentrations. Rising CO2 may reduce the beneficial effects of biogenic isoprene emission, with implications for species competition. This has potential consequences for future climate warming, as isoprene emitted from vegetation has strong effects on global atmospheric chemistry.

Lipidomics of essential fatty acids and oxygenated metabolites

Polyunsaturated fatty acids in mammals may be oxygenated into a myriad of bioactive products through di- and monooxygenases, products that are rapidly degraded to control their action. To evaluate the phenotypes of biological systems regarding this wide family of compounds, a lipidomics approach in function of time and compartments would be relevant. The current review takes into consideration most of the diverse oxygenated metabolites of essential fatty acids at large and their immediate degradation products. Their biological function and life span are considered. Overall, this is a fluxolipidomics approach that is emerging.

Defense activated by 9-lipoxygenase-derived oxylipins requires specific mitochondrial proteins

9-Lipoxygenases (9-LOXs) initiate fatty acid oxygenation, resulting in the formation of oxylipins activating plant defense against hemibiotrophic pathogenic bacteria. Previous studies using nonresponding to oxylipins (noxy), a series of Arabidopsis (Arabidopsis thaliana) mutants insensitive to the 9-LOX product 9-hydroxy-10,12,15-octadecatrienoic acid (9-HOT), have demonstrated the importance of cell wall modifications as a component of 9-LOX-induced defense. Here, we show that a majority (71%) of 41 studied noxy mutants have an added insensitivity to isoxaben, an herbicide inhibiting cellulose synthesis and altering the cell wall. The specific mutants noxy2, noxy15, and noxy38, insensitive to both 9-HOT and isoxaben, displayed enhanced susceptibility to Pseudomonas syringae DC3000 as well as reduced activation of salicylic acid-responding genes. Map-based cloning identified the mutation in noxy2 as At5g11630 encoding an uncharacterized mitochondrial protein, designated NOXY2. Moreover, noxy15 and noxy38 were mapped at the DYNAMIN RELATED PROTEIN3A and FRIENDLY MITOCHONDRIA loci, respectively. Fluorescence microscopy and molecular analyses revealed that the three noxy mutants characterized exhibit mitochondrial dysfunction and that 9-HOT added to wild-type Arabidopsis causes mitochondrial aggregation and loss of mitochondrial membrane potential. The results suggest that the defensive responses and cell wall modifications caused by 9-HOT are under mitochondrial retrograde control and that mitochondria play a fundamental role in innate immunity signaling.

ROS-mediated lipid peroxidation and RES-activated signaling

Nonenzymatic lipid oxidation is usually viewed as deleterious. But if this is the case, then why does it occur so frequently in cells? Here we review the mechanisms of membrane peroxidation and examine the genesis of reactive electrophile species (RES). Recent evidence suggests that during stress, both lipid peroxidation and RES generation can benefit cells. New results from genetic approaches support a model in which entire membranes can act as supramolecular sinks for singlet oxygen, the predominant reactive oxygen species (ROS) in plastids. RES reprogram gene expression through a class II TGA transcription factor module as well as other, unknown signaling pathways. We propose a framework to explain how RES signaling promotes cell "REScue" by stimulating the expression of genes encoding detoxification functions, cell cycle regulators, and chaperones. The majority of the known biological activities of oxygenated lipids (oxylipins) in plants are mediated either by jasmonate perception or through RES signaling networks.