Fatty acids of bacterial origin in contemporary marine sediments

Crassostrea gigas spat were fed diets of Pavlova lutheri, Dunaliella tertiolecta or Tetraselmis suecica . The D. tertiolecta diet contained no fatty acid longer or more unsaturated than linolenic acid (18:3ω3) and the T. suecica diet was deficient in decosahexaenoic acid (22:6ω3). The algal diets were supplemented with micro-encapsulated triolein, oyster lipid extract or 22:6ω3. Spat were also starved or fed carbohydrate diets.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0025315400047056

The effect of algal and artificial diets on the growth and fatty acid composition of Crassostrea gigas Spat

The polyunsaturated fatty acid (PUFA) composition of the mammalian central nervous system is almost wholly composed of two long-chain polyunsaturated fatty acids (LC-PUFA), docosahexaenoic acid (DHA) and arachidonic acid (AA). PUFA are dietarily essential, thus normal infant/neonatal brain, intellectual growth and development cannot be accomplished if they are deficient during pregnancy and lactation. Uniquely in the human species, the fetal brain consumes 70% of the energy delivered to it by mother. DHA and AA are needed to construct placental and fetal tissues for cell membrane growth, structure and function. Contemporary evidence shows that the maternal circulation is depleted of AA and DHA during fetal growth. Sustaining normal adult human brain function also requires LC-PUFA.Homo sapiens is unlikely to have evolved a large, complex, metabolically expensive brain in an environment which did not provide abundant dietary LC-PUFA. Conversion of 18-carbon PUFA from vegetation to AA and DHA is considered quantitatively insufficient due to a combination of high rates of PUFA oxidation for energy, inefficient and rate limited enzymatic conversion and substrate recycling. The littoral marine and lacustrine food chains provide consistently greater amounts of pre-formed LC-PUFA than the terrestrial food chain. Dietary levels of DHA are 2.5-100 fold higher for equivalent weights of marine fish or shellfish vs. lean or fat terrestrial meats. Mammalian brain tissue and bird egg yolks, especially from marine birds, are the richest terrestrial sources of LC-PUFA. However, land animal adipose fats have been linked to vascular disease and mental ill-health, whereas marine lipids have been demonstrated to be protective. At South African Capesites, large shell middens and fish remains are associated with evidence for some of the earliest modern humans. Cape sites dating from 100 to 18 kya cluster within 200 km of the present coast. Evidence of early H. sapiens is also found around the Rift Valley lakes and up the Nile Corridor into the Middle East; in some cases there is an association with the use of littoral resources. Exploitation of river, estuarine, stranded and spawning fish, shellfish and sea bird nestlings and eggs by Homo could have provided essential dietary LC-PUFA for men, women, and children without requiring organized hunting/fishing, or sophisticated social behavior. It is however, predictable from the present evidence that exploitation of this food resource would have provided the advantage in multi-generational brain development which would have made possible the advent of H. sapiens. Restriction to land based foods as postulated by the savannah and other hypotheses would have led to degeneration of the brain and vascular system as happened without exception in all other land based apes and mammals as they evolved larger bodies.

Brain-specific lipids from marine, lacustrine, or terrestrial food resources: potential impact on early African Homo sapiens.

The biochemical composition of krill, Euphausia superba Dana, from South Georgia

Particulate organic matter collected in sediment traps from various oceanic regimes— Sargasso Sea, equatorial North Atlantic, central North Pacific, California Current, and Peru coastal upwelling—have been analyzed for their lipid and amino acid composition and flux. Despite rapid settling of the large particles through the water column and a relatively small depth gradient for total organic carbon flux, there are major changes in the composition and flux of lipids and amino acids associated with the particles. The rapid disappearance of the more labile compounds, such as amino acids and polyunsaturated fatty acids, with increasing depth indicates that the major sources of such compounds are in the upper part of the water column and that they are readily degraded as the particles sink. On the other hand, the intermittent appearance of large amounts of wax ester, along with the changing fatty acid composition of the particles, points to deep-water sources for some of these compounds.

Biogeochemistry of particulate organic matter in the oceans: results from sediment trap experiments

1. 1. A critical examination of the fatty acids from total lipids and certain lipid fractions of the periwinkle (Littorina littorea), moon snal (Lunatia trisepriata) and sand shrimp (Crangon septemspinosus) has been carried out by open-tubular gas-liquid chromatography. 2. 2. In the mollusc lipids two sets of novel fatty acids were detected in analyses by open-tubular column gas-lipid chromatography. These had previously been respectively included in packed column analyses with the eicosenoic and docosenoic acids. 3. 3. These acids are believed to have non-methylene-interrupted structures in which two of the three eicosadienoic acids each have one ethylenic bond in the Δ 5 position and the others in positions mimicking the corresponding normal monoethylenic fatty acids, while in two docosadienoic acids the first ethylenic bond is thought to be in the Δ 7 position. 4. 4. These novel fatty acids were not obvious components in the lipids of the sand shrimp which, however, shared with the molluscs emphasis on chain extension of 9-hexadecenoic acid to 13-eicosenoic acid.

Non-methylene-interrupted fatty acids in lipids of shallow-water marine invertebrates: A comparison of two molluscs (Littorina littorea and Lunatia triseriata) with the sand shrimp (Crangon septemspinosus)

1. 1. Marine molluscs (periwinkle, oyster, quahaug) were found to contain isoprenoid, iso, anteiso and normal odd-numbered fatty acids qualitatively similar to those in higher aquatic life forms. 2. 2. In all three species the branched-chain and normal odd-numbered fatty acids tended to be quantitatively associated with trends in the neighbouring normal even-numbered fatty acids, specifically with myristic, palmitic and stearic acids. 3. 3. Periwinkle lipids had very little phytanic or pristanic acids, suggesting an adaptation to rapidly degrade ingested phytol. The obvious degradation product was 4,8,12-trimethyltridecanoic acid.

The distribution of saturated and isoprenoid fatty acids in the lipids of three species of molluscs, Littorina littorea, Crassostrea virginica and Venus mercenaria

1.	
1. The fatty acids of depot fats of three species of Atlantic marine turtles and six species of North American fresh-water turtles have been determined.

2.	
2. Dermochelys coriacea was exceptional in having 9·5% lauric acid, possibly replacing palmitic acid.

3.	
3. Trans-6-hexadecenoic acid was found only in the marine species.

4.	
4. Dermatemys mawi could be differentiated from the other fresh-water species by details of fatty acids indicative of a herbivorous diet.

S.N. Hooper

Papers

Non-methylene-interrupted fatty acids in lipids of shallow-water marine invertebrates: A comparison of two molluscs (Littorina littorea and Lunatia triseriata) with the sand shrimp (Crangon septemspinosus)

The distribution of saturated and isoprenoid fatty acids in the lipids of three species of molluscs, Littorina littorea, Crassostrea virginica and Venus mercenaria

Comparison of the fatty acid compositions of depot fats from fresh-water and marine turtles