Eicosatetraenoic acid (ETA) designates any straight chain 20:4

fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, fr ...

. Eicosatetraenoic acid belongs to the family of

eicosanoid Eicosanoids are signaling molecules made by the enzymatic or non-enzymatic oxidation of arachidonic acid or other polyunsaturated fatty acids (PUFAs) that are, similar to arachidonic acid, around 20 carbon units in length. Eicosanoids are a sub-c ...

molecule A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...

s synthesized from oxidized

polyunsaturated fatty acid Polyunsaturated fatty acids (PUFAs) are fatty acids that contain more than one double bond in their backbone. This class includes many important compounds, such as essential fatty acids and those that give drying oils their characteristic proper ...

s (PUFAs) to mediate

cell-cell communication In biology, cell signaling (cell signalling in British English) or cell communication is the ability of a cell to receive, process, and transmit signals with its environment and with itself. Cell signaling is a fundamental property of all cellula ...

. The eicosanoids, working in tandem, contribute to a

lipid signaling Lipid signaling, broadly defined, refers to any biological signaling event involving a lipid messenger that binds a protein target, such as a receptor, kinase or phosphatase, which in turn mediate the effects of these lipids on specific cellular r ...

complex widely responsible for inducing an inflammatory

immune response An immune response is a reaction which occurs within an organism for the purpose of defending against foreign invaders. These invaders include a wide variety of different microorganisms including viruses, bacteria, parasites, and fungi which could ...

. Common signs of inflammation are both internal and external, with effects like visible redness, pain in the surrounding area, swelling, and the sensation of heat—many of these an effect of varying eicosanoid species. These effects are associated with and have been observed in patients with cancers and various neurological/metabolic disorders. :''See

Essential Fatty Acid Essential fatty acids, or EFAs, are fatty acids that humans and other animals must ingest because the body requires them for good health but cannot synthesize them. Only two fatty acids are known to be essential for humans: alpha-linolenic ac ...

for nomenclature.'' Two

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. Iso ...

s, both of them

essential fatty acid Essential fatty acids, or EFAs, are fatty acids that humans and other animals must ingest because the body requires them for good health but cannot synthesize them. Only two fatty acids are known to be essential for humans: alpha-linolenic ac ...

s, are of particular interest: * ''all-cis''-5,8,11,14-eicosatetraenoic acid is an ω-6 fatty acid with the trivial name

arachidonic acid Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega-6 fatty acid 20:4(ω-6), or 20:4(5,8,11,14). It is structurally related to the saturated arachidic acid found in cupuaçu butter. Its name derives from the New Latin word ''arachi ...

. It is formed by a desaturation of dihomo-gamma-linolenic acid (DGLA, 20:3 ω-6). * ''all-cis''-8,11,14,17-eicosatetraenoic acid is an ω-3 fatty acid. It is an intermediate between

stearidonic acid Stearidonic acid (SDA: C18 H28 O2; 18: 4, n-3) is an ω-3 fatty acid, sometimes called moroctic acid. It is biosynthesized from alpha-linolenic acid (ALA: C18H30O2; 18:3, n-3) by the enzyme delta-6-desaturase, that removes two hydrogen (H) atoms ...

(18:4 ω-3) and

eicosapentaenoic acid Eicosapentaenoic acid (EPA; also icosapentaenoic acid) is an omega-3 fatty acid. In physiological literature, it is given the name 20:5(n-3). It also has the trivial name timnodonic acid. In chemical structure, EPA is a carboxylic acid with a 20-c ...

(EPA, 20:5 ω-3) Some chemistry sources define 'arachadonic acid' to designate any of the eicosatetraenoic acids. However, almost all writings in biology, medicine and nutrition limit the use of the term 'arachidonic acid' to ''all-cis''-5,8,11,14-eicosatetraenoic acid (ω-6).

Recent studies

ETA is found in

green-lipped mussel ''Perna canaliculus'', the New Zealand green-lipped mussel, also known as the New Zealand mussel, the greenshell mussel, ''kuku'', and ''kutai'', is a bivalve mollusc in the family Mytilidae (the true mussels). ''P. canaliculus'' has economic i ...

and appears to act as dual inhibitor of arachidonic acid oxygenation by both the cyclooxygenase (COX) and lipoxygenase pathway. According to the journal of nutrition, feeding green-lipped mussel to arthritic dogs leads to an improved response. In addition to their inflammatory nature, eicosanoid molecules such as ETA can also contribute to an anti-inflammatory response. Many ω-3-PUFAs are abundantly produced in nature and can be extracted and studied. These molecules have exhibited anti-inflammatory properties and have led scientists to believe that they may serve as relief to patients with rheumatoid arthritis, asthma, and heart disease, afflictions associated with an overly active inflammatory response. ETA, which is much less abundant in nature, has been the subject of significantly less studies. As a member of the eicosanoid family, it is expected that ETA should have a similar positive effect in the human body however there is a lack in its production and therefore a lack in its scientific investigation and understanding. ''

Mortierella alpina ''Mortierella'' species are soil fungi belonging to the order Mortierellales within the subphylum Mortierellomycotina (phylum: Mucoromycota). The widespread genus contains about 85 species. Taxonomy The genus name of ''Mortierella'' is in hon ...

'' 1S-4 is a fungus employed in the biological production of arachidonic acid, and so biotechnology has allowed for the biosynthesis of a mutant strain of this fungus. ''Mortierella alpina'' typically only produces ETA in trace amounts at low temperatures, making it difficult to isolate and examine. This developed mutant strain is capable of producing larger amounts of ETA due to the expression of an ω-3-desaturase gene, typically responsible for the significant production of the more abundant PUFAs.The development of a mutant strain was considered in the context of the over-expression of the endogenous ω-3-desaturase gene versus the heterologous ''Saprolegnia diclina'' Δ17 (''sdd17m'') desaturase gene. The endogenous ω-3-desaturase gene transformed fungi had ETA at 42.1% in total lipid concentration, 84.2-fold and 3.2-fold more than two wild-type strain fungi when contrasted at a temperature of 12 degrees Celsius. While no ETA accumulation is documented at 28 degrees Celsius, the mutant strain of the fungus transformed with the heterologous ''sdd17m''gene exhibited 24.9% of the total lipid content at the same temperature, indicating success in the genetic alteration and abundance of ETA provided for the study, at a variety of different temperatures and conditions. This allows for a more inclusive analysis of the effects of ETA on the human body and provides new insight for medical treatments to inflammatory conditions, given the newfound methods for producing and collecting these molecules for isolation and analysis. This study provides insight as to how many molecules may have multiple functions, some of which are unknown and are still being determined by scientists. The duality of molecules like eicosatetraenoic acid and other eicosanoids, both as inflammatory and anti-inflammatory molecules, is a point of compelling research.

References

{{Reflist, 30em Fatty acids Alkenoic acids

Recent studies

See also

References