Β. Hydrocarbons
169
sense, i.e., they are primary rather than secondary metabolites. Furthermore,
it is too soon to know whether marine plants and animals elaborate any
unique fatty acids. While fatty acid research that is related to marine organisms, prominently of course to fishes and mammals, dates back many years (for
reviews see Hilditch and Williams, 1964 ; Stansky, 1967), much of the work prior
to about 1960 suffers from lack of adequate separation techniques (glc) and of
physical tools of structural determination (particularly mass spectrometry).
Additionally, the bulk of all the early work on fatty acid chemistry was
undertaken with a nutritional (percent saturated vs. unsaturated fatty acids)
rather than a structural bias, thus rendering the results only marginally
relevant to our discussion. Other interesting fatty acid research has been
undertaken primarily from other than a structural chemical viewpoint. For
example, the apparently rare occurrence of polyunsaturated acids in bluegreen algae (Holton et al., 1968) is essentially a chemotaxonomic investigation; or the stereochemistry of fatty acid dehydrogenation (Morris et al.,
1968) was undertaken in connection with biosynthetic work; or, e.g., the
work on fatty acid composition of blue-green algae by Parker et al. (1967)
was part of a geochemical study. All these researches are only of peripheral
interest to our theme. Finally, the sum total of modern and rigorous structural
research on marine-derived fatty acids is still quite modest and our ability to
draw general conclusions is therefore limited.
From the most recent comprehensive reviews on marine lipids (Lovern,
1964; Malins and Wekell, 1970) it appears that the fatty acid make-up of
marine lipids is complex and that its composition in a particular organism
may well be characteristic of a given species of plant or animal. It remains to
be seen, however, whether any uniquely marine structural features will
eventually emerge, e.g., 6,9,12,15-hexadecatetraenoic acid of the marine
diatom Biddulphia sinensis with its unusual terminal double bond (Klenk and
Eberhagen, 1962); or the twenty-two carbon acid with six carbon-carbon
double bonds (docosahexaenoic acid), at C-4, C-10, C-13, C-16, and C-19,
which has been identified from the dinoflegellate Gyrodinium cohnii (Harrington and Holz, 1968) and from cod liver oil (Hinchcliffe and Riley, 1971). It
would, for instance, be not at all surprising if some unique halogenated fatty
acids were to be isolated from marine sources.
B. Hydrocarbons
Hydrocarbons with an unbranched carbon skeleton have an evident biogenetic relationship to fatty acids. Since in the course of biosynthesis at
least one transformation, i.e., decarboxylation, must take place, an opportunity arises for concomitant and independent, or for decarboxylation-triggered
169
sense, i.e., they are primary rather than secondary metabolites. Furthermore,
it is too soon to know whether marine plants and animals elaborate any
unique fatty acids. While fatty acid research that is related to marine organisms, prominently of course to fishes and mammals, dates back many years (for
reviews see Hilditch and Williams, 1964 ; Stansky, 1967), much of the work prior
to about 1960 suffers from lack of adequate separation techniques (glc) and of
physical tools of structural determination (particularly mass spectrometry).
Additionally, the bulk of all the early work on fatty acid chemistry was
undertaken with a nutritional (percent saturated vs. unsaturated fatty acids)
rather than a structural bias, thus rendering the results only marginally
relevant to our discussion. Other interesting fatty acid research has been
undertaken primarily from other than a structural chemical viewpoint. For
example, the apparently rare occurrence of polyunsaturated acids in bluegreen algae (Holton et al., 1968) is essentially a chemotaxonomic investigation; or the stereochemistry of fatty acid dehydrogenation (Morris et al.,
1968) was undertaken in connection with biosynthetic work; or, e.g., the
work on fatty acid composition of blue-green algae by Parker et al. (1967)
was part of a geochemical study. All these researches are only of peripheral
interest to our theme. Finally, the sum total of modern and rigorous structural
research on marine-derived fatty acids is still quite modest and our ability to
draw general conclusions is therefore limited.
From the most recent comprehensive reviews on marine lipids (Lovern,
1964; Malins and Wekell, 1970) it appears that the fatty acid make-up of
marine lipids is complex and that its composition in a particular organism
may well be characteristic of a given species of plant or animal. It remains to
be seen, however, whether any uniquely marine structural features will
eventually emerge, e.g., 6,9,12,15-hexadecatetraenoic acid of the marine
diatom Biddulphia sinensis with its unusual terminal double bond (Klenk and
Eberhagen, 1962); or the twenty-two carbon acid with six carbon-carbon
double bonds (docosahexaenoic acid), at C-4, C-10, C-13, C-16, and C-19,
which has been identified from the dinoflegellate Gyrodinium cohnii (Harrington and Holz, 1968) and from cod liver oil (Hinchcliffe and Riley, 1971). It
would, for instance, be not at all surprising if some unique halogenated fatty
acids were to be isolated from marine sources.
B. Hydrocarbons
Hydrocarbons with an unbranched carbon skeleton have an evident biogenetic relationship to fatty acids. Since in the course of biosynthesis at
least one transformation, i.e., decarboxylation, must take place, an opportunity arises for concomitant and independent, or for decarboxylation-triggered