Dear Colleagues,

Fatty acids (FA) are especially suitable as tools to examine processes that range from cellular to macroscopic levels of organization. Lipids comprise a large group of chemically heterogeneous compounds, the majority of which include esters of FA as part of their structure. FA represent, thus, the “building blocks” of lipids and are the largest constituent of neutral lipids, such as triacylglycerols (TAG) and wax esters (WE), which have storage functions, as well as of the polar phospholipids which are important structural components of cell membranes. FA can be used directly for energy production through beta-oxidation; there are indications that polyunsaturated fatty acids (PUFA) have nutritionally stabilizing functions; and essential fatty acids (EFA) are precursors to eicosanoid signalling molecules (i.e. prostaglandins prostacyclins, the thromboxanes and the leukotrienes). FA derived metabolites (e.g. oxylipins) may also mediate chemical interactions controlling herbivory patterns and reproduction of aquatic organisms with implications for the functioning of aquatic food webs.

Studies on FA and their metabolism are important in several research fields including, e.g. biology, bacteriology, ecology and oncology. Specific FA and their ratios in the cellular membranes of organisms may be used as biomarkers to aid in the identification of organisms, food web connections or to study adaptation of bacterial cells to toxic compounds or environmental conditions. The ability exhibited by actinomycetes to thrive under conditions fatal to other bacteria is ascribed to the presence of mycolic acids, i.e. long FA in its unusually robust cell wall. Specialized lipids allow bacteria and archaea to live under extreme conditions, such as those found in abyssal marine trenches or hot vents, where they form the base of the local food web. Mycobacterium tuberculosis cells in the human lung enter a dormant state within granulomas where they survive by incorporating FA from the host triacylglycerols into lipid droplets. Alterations in FA metabolism in cancer cells are increasingly recognised and more attention is being devoted to the fact that in these cells, carbon must be diverted from energy production to FA for biosynthesis of membranes and signalling molecules.

Lipid and FA research has gained considerable applied importance in human nutrition and health as human are “top predators” that require essential dietary nutrients in their diet, and many signal and disease related mechanisms involve lipid components. In humans, PUFA like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) play key roles in heart health, immune and inflammatory responses, visual acuity as well being major components of neurological tissues, such as the brain and spinal cord. Consumer health trends further contribute to the current interest in lipids as the debate over the benefits and risks of PUFA, trans-unsaturated and hydrogenated FA for human health appear daily in the media.

In this Special Issue, we intend to highlight the importance of FA studies to answer important questions in different research fields.

Dr. Carla C. C. R. de Carvalho
Dr. Maria José Caramujo
Guest Editors

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• saturated fatty acids
• unsaturated fatty acids
• polyunsaturated fatty acids
• omega-3 fatty acids
• specialized lipids
• phospholipids
• storage lipids
• lipidomics
• biofuels