Acyl lipids in Arabidopsis and all other plants have a myriad of diverse functions. These include providing the core diffusion barrier of the membranes that separates cells and subcellular organelles. This function alone involves more than 10 membrane lipid classes, including the phospholipids, galactolipids, and sphingolipids, and within each class the variations in acyl chain composition expand the number of structures to several hundred possible molecular species. Acyl lipids in the form of triacylglycerol account for 35% of the weight of Arabidopsis seeds and represent their major form of carbon and energy storage. A layer of cutin and cuticular waxes that restricts the loss of water and provides protection from invasions by pathogens and other stresses covers the entire aerial surface of Arabidopsis. Similar functions are provided by suberin and its associated waxes that are localized in roots, seed coats, and abscission zones and are produced in response to wounding. This chapter focuses on the metabolic pathways that are associated with the biosynthesis and degradation of the acyl lipids mentioned above. These pathways, enzymes, and genes are also presented in detail in an associated website (ARALIP: http://aralip.plantbiology.msu.edu/). Protocols and methods used for analysis of Arabidopsis lipids are provided. Finally, a detailed summary of the composition of Arabidopsis lipids is provided in three figures and 15 tables.

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Acyl-Lipid Metabolism

Omega-3 fatty acids EPA and DHA: health benefits throughout life.

The gastrointestinal epithelium forms the boundary between the body and external environment. It effectively provides a selective permeable barrier that limits the permeation of luminal noxious molecules, such as pathogens, toxins, and antigens, while allowing the appropriate absorption of nutrients and water. This selective permeable barrier is achieved by intercellular tight junction (TJ) structures, which regulate paracellular permeability. Disruption of the intestinal TJ barrier, followed by permeation of luminal noxious molecules, induces a perturbation of the mucosal immune system and inflammation, and can act as a trigger for the development of intestinal and systemic diseases. In this context, much effort has been taken to understand the roles of extracellular factors, including cytokines, pathogens, and food factors, for the regulation of the intestinal TJ barrier. Here, I discuss the regulation of the intestinal TJ barrier together with its implications for the pathogenesis of diseases.

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Regulation of intestinal epithelial permeability by tight junctions

The marine environment represents a relatively untapped source of functional ingredients that can be applied to various aspects of food processing, storage, and fortification. Moreover, numerous marine-based compounds have been identified as having diverse biological activities, with some reported to interfere with the pathogenesis of diseases. Bioactive peptides isolated from fish protein hydrolysates as well as algal fucans, galactans and alginates have been shown to possess anticoagulant, anticancer and hypocholesterolemic activities. Additionally, fish oils and marine bacteria are excellent sources of omega-3 fatty acids, while crustaceans and seaweeds contain powerful antioxidants such as carotenoids and phenolic compounds. On the basis of their bioactive properties, this review focuses on the potential use of marine-derived compounds as functional food ingredients for health maintenance and the prevention of chronic diseases.

https://www.mdpi.com/1660-3397/9/6/1056/pdf

Marine Bioactives as Functional Food Ingredients: Potential to Reduce the Incidence of Chronic Diseases

A mixture of neutral short-chain galactooligosaccharides (scGOS) and long-chain fructooligosaccharides (lcFOS) has been shown to reduce the incidence of atopic dermatitis (AD) and infectious episodes during the first 6 mo of life. This dual protection occurred through the intervention period. The present study evaluated if these protective effects were lasting beyond the intervention period. In a prospective, randomized, double-blind, placebo-controlled design, healthy term infants with a parental history of atopy were fed either a prebiotic-supplemented (8 g/L scGOS/lcFOS) or placebo-supplemented (8 g/L maltodextrin) hypoallergenic formula during the first 6 mo of life. Following this intervention period, blind follow-up continued until 2 y of life. Primary endpoints were cumulative incidence of allergic manifestations. Secondary endpoints were number of infectious episodes and growth. Of 152 participants, 134 infants (68 in placebo, 66 in intervention group) completed the follow-up. During this period, infants in the scGOS/lcFOS group had significantly lower incidence of allergic manifestations. Cumulative incidences for AD, recurrent wheezing, and allergic urticaria were higher in the placebo group, (27.9, 20.6, and 10.3%, respectively) than in the intervention group (13.6, 7.6, and 1.5%) (P < 0.05). Infants in the scGOS/lcFOS group had fewer episodes of physician-diagnosed overall and upper respiratory tract infections (P < 0.01), fever episodes (P < 0.00001), and fewer antibiotic prescriptions (P < 0.05). Growth was normal and similar in both groups. Early dietary intervention with oligosaccharide prebiotics has a protective effect against both allergic manifestations and infections. The observed dual protection lasting beyond the intervention period suggests that an immune modulating effect through the intestinal flora modification may be the principal mechanism of action.

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Early Dietary Intervention with a Mixture of Prebiotic Oligosaccharides Reduces the Incidence of Allergic Manifestations and Infections during the First Two Years of Life

Background
The intestinal mucosa functions as a barrier against harmful dietary and microbial antigens. An intact gut barrier forms a prerequisite for protection against infection and allergy. Both allergic and inflammatory mediators (e.g. IL-4, IFN-γ) are known to compromise the epithelial barrier integrity by enhancing permeability. Breast milk provides protection against infection and allergy and contains polyunsaturated fatty acids (PUFA).

Polyunsaturated fatty acids support epithelial barrier integrity and reduce IL-4 mediated permeability in vitro.

Shelf-life of dietary products and the need for health supporting functional ingredients often require components with high anti-oxidative properties. The study aimed at the characterisation of peptides with antioxidant properties from enzymatically hydrolysed soybean protein isolate. Soybean protein isolate was hydrolysed with a food grade pancreatic trypsin/chymotrypsin for industrial applications, ultrafiltered and the permeate was fractionated by size exclusion chromatography. Anti-oxidative properties of these fractions were tested in a Trolox®-equivalent-anti-oxidative capacity assay, which is based on the absorbance suppression of 2,2′-azinobis(3-ethyl benzothiazoline-6-sulfonate) radical cations by anti-oxidative substances at λ 414 nm. The amino acid compositions and sequences of the peptide fractions were determined by liquid chromatography and mass spectrometry analysis. Compared to the intact soybean protein isolate a peptide fraction with an anti-oxidative capacity of 113 mg TEAC/g was obtained. This fraction was shown to be enriched in peptides smaller than 1 kDa with prevailing aromatic amino acid residues. Nine peptides derived from glycinin and β-conglycinin were sequenced by tandem mass spectrometry. The particular sequences were synthesized and assayed. The synthetic peptide analogue TTYY (β-conglycinin fragment 291–294) revealed significant radical scavenging properties of 13.6 up to 59.6% with 0.18–18 mM in a concentration dependent manner. Peptides from soybean protein isolate were shown to possess anti-oxidative capacities which might be linked to the presence of carboxy terminal tyrosine. These findings offer new functional application possibilities in nutrition, cosmetics and pharmaceuticals.

Anti-oxidative capacity of enzymatically released peptides from soybean protein isolate

The amount and quality of dietary fatty acids can modulate the fat metabolism. This dietary intervention is based on the different metabolic pathways of long-chain saturated fatty acids (LCFA), which are mostly stored in adipocytic triacylglycerols, medium-chain fatty acids (MCFA) which are preferentially available for hepatic mitochondrial β-oxidation and n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) suggested to modulate fat oxidation and storage by stimulating the peroxisomal β-oxidation. Combined dietary MCFA and n-3 LCPUFA without LCFA may synergistically stimulate fatty acid oxidation resulting in blood lipid clearance and LCFA release from adipocytes. In a short term, parallel, randomized, double-blind trial effects on the fatty acid metabolism of 10 healthy volunteers (Body Mass Index 25–30) of a formula containing 72% MCFA and 22% n-3 LCPUFA without LCFA (intake: 1.500 kcal/day; fat: 55.5% of energy) were measured in comparison to an isoenergetic formula with equal fat amount and LCFA dominated lipid profile. The plasma triacylglycerol (p < 0.1) and cholesterol (p < 0.05) content decreased in the test group. The n-3/n-6 LCPUFA (≥ C 20) ratio increased (p < 0.0001) after 4 days treatment. The LCFA content was similar in both groups despite missing LCFA in the test formula indicating LCFA release from adipocytes into the plasma. Both groups significantly reduced body weight considerably 4 kg (p < 0.01) and fat mass up to 50% of weight loss (p < 0.05). Combined dietary 72% MCFA and 22% n-3 LCPUFA without LCFA stimulate the fatty acid oxidation and release from adipocytes without affecting any safety parameters measured.

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Short term effects of dietary medium-chain fatty acids and n-3 long-chain polyunsaturated fatty acids on the fat metabolism of healthy volunteers

Background: We investigated the anti-inflammatory potential of n–3 polyunsaturated fatty acids (PUFA) on specific bronchial inflammation. Allergic asthmatics were challenged using a

Effect of n–3 Polyunsaturated Fatty Acids in Asthma after Low-Dose Allergen Challenge

The demand for health-promoting food ingredients rises within an increasing market worldwide. Different milks fermented with bacteria, yeasts, moulds or enzymes from animal, plant and microbial sources offer a broad range of possibilities to cover different health aspects with new bioactive components. By the fermentation process interesting ingredients are enriched and released from the matrix, like lactoferrin, micro-nutrients, CLA and sphingolipids or synthesized, such as exo-polysaccharides and bioactive peptides. In particular, milk derived bioactive peptides exert several important health-promoting activities, such as anti-hypertensive, anti-microbial, anti-oxidative, immune-modulatory, opioid and mineral-binding properties. Milk-fermentation processes with probiotic bacteria synergistically combine health supporting bacterial and milk ingredient aspects which include new therapeutic solutions concerning hypercholesterolemia, carcinogenic intoxications, treatment of diarrhea, reduction of intestine pathogens, and supporting natural immune defense. Especially, milk-proteins and associated bioactive peptides released during microbial or enzymatic fermentation of milk offer a broad spectrum of new functional properties, for instance anti-hypertensive, anti-microbial, anti-oxidative, immuno-modulatory, opioid and mineral-binding properties. This review aimed at discussing recent research activities on physiological purposes and technical process aspects of functional components from fermented milk with a specific focus on biofunctional peptides released from fermented milk proteins.

Christopher Beermann

Papers

Polyunsaturated fatty acids support epithelial barrier integrity and reduce IL-4 mediated permeability in vitro.

Anti-oxidative capacity of enzymatically released peptides from soybean protein isolate

Short term effects of dietary medium-chain fatty acids and n-3 long-chain polyunsaturated fatty acids on the fat metabolism of healthy volunteers

Effect of n–3 Polyunsaturated Fatty Acids in Asthma after Low-Dose Allergen Challenge

Physiological properties of milk ingredients released by fermentation