MARINE CHEMICAL AND MEDICINE RESOURCES
S. Ali and C. Llewellyn, Plymouth Marine Laboratory,
Plymouth, UK
& 2009 Elsevier Ltd. All rights reserved.
Introduction
The marine environment consists of several defined
habitats ranging from the sea surface microlayer
which encompasses the first few microns of the water
column, through the bulk water column itself, down
to the ocean floor and the subsurface sediments
underneath which can be found hydrothermal vents,
cold seeps, hydrocarbon seeps, and saturated brines,
as well as a wide range of mineral and geological
variation. It has become increasingly apparent that
within all these oceanic layers there is a diversity of
micro- and macroorganisms capable of generating a
plethora of previously undescribed molecules through
novel metabolic pathways which could be of value to
both industry and the clinic. The biological diversity
in some marine ecosystems may exceed that of the
tropical rain forests and this is supported by the
presence of 34 out of the 36 phyla of life. This biodiversity stems from the wide range of environmental
conditions to which marine organisms have adapted
for survival, including extremes of pH (acid and
alkali), temperature (high and low), salinity, pressure,
and chemical toxicity (complex polycyclic hydrocarbons, heavy metals).
Marine organisms currently being exploited for
biotechnology include sponges, tunicates, bryozoans,
mollusks, bacteria, cyanobacteria, macroalgae (seaweeds), and microalgae. These organisms have produced compounds with good activities for a range of
infectious and noninfectious disease with high specificity for the target molecule (usually an enzyme).
Targets of marine natural products which may be
clinically relevant include ion channels and G-proteincoupled receptors, protein serine-threonine kinases,
protein tyrosine kinases, phospholipase A 2 , microtubule-interfering agents (of which the largest number
identified are of marine origin), and DNA-interactive
compounds. In addition to small organic molecules,
marine organisms are increasingly being recognized as
a potential source of novel enzymes which could be of
industrial and pharmaceutical importance. More than
30 000 diseases have been clinically described, yet
less than one-third of these can be treated based on
symptoms and only a small number can be cured.
Thus, the potential market for novel marine compounds for clinical development is enormous. In
addition to providing new molecules for direct clinical
intervention, the marine environment is also rich in
compounds which are finding uses as natural additives in foods, as nutritional supplements including
color additives and antioxidants, and as vitamins,
oils, and cofactors which enhance general well-being.
Marine organisms are also increasingly providing
new solutions to developments in such diverse fields
as bioremediation, biocatalysis and chemistry, materials science, nanotechnology, and energy. Some of
the potential uses of marine products are summarized
in Figure 1.
The oceans have long been a source of nutrients,
additives, and medicines derived from marine mammals and fish; however, this article focuses on some
of the potential which is harbored in predominantly
microscopic organisms which are now being increasingly studied for novel bioactive compounds
and chemicals and may provide a sustainable alternative source for new compounds and processes.
Novel Metabolites and Drug Discovery
Marine organisms have long been recognized as a
source of novel metabolites with applications in
human disease therapy. Particular emphasis has been
placed on the invertebrates such as sponges, mollusks,
tunicates, and bryozoans, but more recently advances in genetics and microbial culture have led to a
growing interest in cyanobacteria and marine bacteria. For example, a number of anticancer drugs have
been derived from marine sources such as sponges
which have proven difficult to cultivate and their
metabolites display a structural complexity which
often precludes total chemical synthesis as an option
for potential drug candidates. In recent years, studies
have suggested that many of these complex molecules
may in fact be the product of microbes which live in a
symbiotic relationship with the sponge and that some
of these molecules may be the final product of reactions carried out by different organisms. A major
challenge within marine biotechnology will be to ascertain the nature of the organisms present in the
symbiotic relationship and to identify the pathways
involved in metabolite production. A recent advance
in molecular biology with the development of metagenomics has opened up the possibility of organismindependent cultivation of genetic material and
subsequent screening and characterization of that
112
S. Ali and C. Llewellyn, Plymouth Marine Laboratory,
Plymouth, UK
& 2009 Elsevier Ltd. All rights reserved.
Introduction
The marine environment consists of several defined
habitats ranging from the sea surface microlayer
which encompasses the first few microns of the water
column, through the bulk water column itself, down
to the ocean floor and the subsurface sediments
underneath which can be found hydrothermal vents,
cold seeps, hydrocarbon seeps, and saturated brines,
as well as a wide range of mineral and geological
variation. It has become increasingly apparent that
within all these oceanic layers there is a diversity of
micro- and macroorganisms capable of generating a
plethora of previously undescribed molecules through
novel metabolic pathways which could be of value to
both industry and the clinic. The biological diversity
in some marine ecosystems may exceed that of the
tropical rain forests and this is supported by the
presence of 34 out of the 36 phyla of life. This biodiversity stems from the wide range of environmental
conditions to which marine organisms have adapted
for survival, including extremes of pH (acid and
alkali), temperature (high and low), salinity, pressure,
and chemical toxicity (complex polycyclic hydrocarbons, heavy metals).
Marine organisms currently being exploited for
biotechnology include sponges, tunicates, bryozoans,
mollusks, bacteria, cyanobacteria, macroalgae (seaweeds), and microalgae. These organisms have produced compounds with good activities for a range of
infectious and noninfectious disease with high specificity for the target molecule (usually an enzyme).
Targets of marine natural products which may be
clinically relevant include ion channels and G-proteincoupled receptors, protein serine-threonine kinases,
protein tyrosine kinases, phospholipase A 2 , microtubule-interfering agents (of which the largest number
identified are of marine origin), and DNA-interactive
compounds. In addition to small organic molecules,
marine organisms are increasingly being recognized as
a potential source of novel enzymes which could be of
industrial and pharmaceutical importance. More than
30 000 diseases have been clinically described, yet
less than one-third of these can be treated based on
symptoms and only a small number can be cured.
Thus, the potential market for novel marine compounds for clinical development is enormous. In
addition to providing new molecules for direct clinical
intervention, the marine environment is also rich in
compounds which are finding uses as natural additives in foods, as nutritional supplements including
color additives and antioxidants, and as vitamins,
oils, and cofactors which enhance general well-being.
Marine organisms are also increasingly providing
new solutions to developments in such diverse fields
as bioremediation, biocatalysis and chemistry, materials science, nanotechnology, and energy. Some of
the potential uses of marine products are summarized
in Figure 1.
The oceans have long been a source of nutrients,
additives, and medicines derived from marine mammals and fish; however, this article focuses on some
of the potential which is harbored in predominantly
microscopic organisms which are now being increasingly studied for novel bioactive compounds
and chemicals and may provide a sustainable alternative source for new compounds and processes.
Novel Metabolites and Drug Discovery
Marine organisms have long been recognized as a
source of novel metabolites with applications in
human disease therapy. Particular emphasis has been
placed on the invertebrates such as sponges, mollusks,
tunicates, and bryozoans, but more recently advances in genetics and microbial culture have led to a
growing interest in cyanobacteria and marine bacteria. For example, a number of anticancer drugs have
been derived from marine sources such as sponges
which have proven difficult to cultivate and their
metabolites display a structural complexity which
often precludes total chemical synthesis as an option
for potential drug candidates. In recent years, studies
have suggested that many of these complex molecules
may in fact be the product of microbes which live in a
symbiotic relationship with the sponge and that some
of these molecules may be the final product of reactions carried out by different organisms. A major
challenge within marine biotechnology will be to ascertain the nature of the organisms present in the
symbiotic relationship and to identify the pathways
involved in metabolite production. A recent advance
in molecular biology with the development of metagenomics has opened up the possibility of organismindependent cultivation of genetic material and
subsequent screening and characterization of that
112