@Sea - Tortuga's Natural Treasures

To most people, a "natural product" is probably anything made by nature. To the chemists on this expedition, it is a very special type of "product".

To us, natural products, which we also call "secondary metabolites", are low molecular weight (small) compounds which are synthesized (made) by a plant , microorganism or animal which are not essential to sustain life, but which presumably confer an evolutionary advantage. What exactly does this mean?

All cells are made up of chemical compounds. If you watch TV or read magazines, you've probably see advertisements that talk about things called "cholesterol", "lipids", "fats", "protein", "sugars", "triglycerides", etc.. All of these things are chemical compounds that are essential to maintain healthy cells and ultimately healthy people. (Its only when the levels are too high or too low that they cause disease- you have to have all of them to be healthy). Substances such as lipids make up the cell membrane. Proteins such as actin and tubulin give the cells shape. Other proteins (enzymes) carry out chemical reactions within the cell. All of these types of chemical compounds (proteins, lipids, triglycerides, sugars, cholesterol, polysaccharides, amino acids, etc.) must be present to allow the cellular machinery to work. Without these substances, which we call "primary metabolites", the individual cells and thus the organism can not survive.

In contrast, cells or organisms which lack "secondary metabolites" or "natural products" can survive and reproduce. The compounds do not serve an essential function, e.g. they don't make up the cell membrane, or run chemical reactions. They simply aren't essential to the organism.

It takes a lot of energy to make a secondary metabolite. You can think of it as similar to making a cake. Someone has to work to get the money to make a cake, it doesn't come for free. You have to spend money (resources) to buy the ingredients, you have to buy or rent an oven and then you have to pay the electric bill to run the oven. You also have to mix up the ingredients which takes physical energy. All of that energy is used up for something that tastes good, but which you really don't have to have.

It is a similar situation for the organism which makes a natural product. It takes a lot of energy to do it, so, why do the organisms bother?

In order to understand this better, we need to look at the how these animals grow and the habitats in which they live. During the present expedition we will be working primarily with invertebrates such as soft corals, sponges, bryozoans and ascidians, so we will focus on these. If you look at most reefs you can see that almost every square inch of space is inhabited. Competition for space and food is enormous.

Most of the animals are sessile as adults. That means that just like a plant growing in your yard, if something comes by to eat them, they can't get up and run. There are a few invertebrates, such as nudibranchs which can move around, but they really wouldn't set any Olympic speed records. Fish are hundreds of times faster than nudibranchs. As larvae, most of these invertebrates can get around, but once they are ready to metamorphose into adults, they select a home, settle out, metamorphose into a juvenile and if they chose a good spot, they might be able to grow into adults. In general, they can't get up and move if the neighborhood gets bad. This presents a number of interesting problems:

- How can they defend themselves against things that want to eat them?

- How can they keep other animals from moving into their space?

- How can they find a mate if they can't go looking?

- How can they protect themselves from bacterial, fungal or viral infections?

One way is to accomplish all of these tasks is to use secondary metabolites. If you taste bad, or smell bad or are even toxic, you might not get eaten. Even if a fish takes a bite out of the sponge, the rest of it can survive, and many fish can eventually learn what to eat and what not to eat. The same applies to keeping the neighbors from moving in on you. Most of these animals are filter feeders and so compete with each other for the same food source. It makes sense to keep the neighbors away. Some of these animals even go so far as to produce toxic compounds such that they can actually kill off neighboring organisms and take over their space.

One sponge which we might encounter during the expedition which does this is Siphonodictyon coralliphagum. It bores through coral heads and produces a toxic substance which can kill the coral, allowing it to colonize more space.

Reproduction can also be a tough proposition if you can't move around and you live in a water environment. Many of the sessile invertebrates are broadcast spawners. That means that at certain times of the year, they simultaneously release sperm and eggs into the water column. Is it just chance that allows the sperm to find the eggs? For at least one soft coral which lives in Australia, it has been demonstrated that a natural products present in the eggs actually act as sperm attractants.

Another role of natural products can be to act as chemical lighthouses to guide the larvae back to the adult organism. The larvae can sense these compounds and actively swim back to the parent, thus insuring that they settle in a habitat which is suitable for them to live in (the right neighborhood).

On the opposite side, the compounds can act to stop larvae of other species from settling on top of them. They can do this by making it a "bad neighborhood" (e.g. next door to the land fill) or by actually making it toxic for the other species (would you move into Love canal?).

Bacteria, fungi and viruses are all present within marine habitats. Just like people, marine organisms can suffer from infection. Most of these animals have only a primitive immune system, if any at all. Many of the secondary metabolites we encounter are strong antibiotics, antifungal and/or antiviral agents, and this may be another reason why they are produced.

For most of the compounds we encounter, we really do not really understand why they are present, but luckily for us, we do not have to understand why they are there, it is enough that they are.

Most people encounter natural products every day.
Do you drink coffee? The natural product caffeine is present in the beans of both the coffee and cola plants. Caffeine acts as a stimulant in mammalian systems.

Many clinically used medicines are natural products.
Morphine comes from the opium poppy and is a potent pain reliever.

What is a Deep-water Coral Reef? - John Reed

The Search for New Antibiotics and Cancer Drugs

Extraction - First Step Towards Biological Screening

Gleaning Clues to Climate Change from Deep-water Sponges and Corals - Brad Rosenheim

My research involves the use of accretionary skeletons like those deposited by certain corals and sponges to interpret the conditions under which they formed. This is done geochemically. Using a combination of chemical theory and environmental calibration, past research has established relationships between the chemical signatures in these skeletons and the ambient environment around the organism as it lived. In organisms that preserve older portions of skeleton while building new skeleton, this type of knowledge becomes very important. Whereas modern day oceanographers can sail the world (well, most of it) and directly measure temperature, salinity, and currents of the ocean, "paleoceanographers" are left with only proxies of these parameters to elongate our short instrumental record. My work has involved calibrating species of sclerosponges that live deeper than most massive corals for paleoclimate reconstruction and comparing those records to both shallow and deep sea corals. This gives us a better idea of where heat, which is acquired and given off by the ocean at the surface, is transported on the subsurface. Thus I am very interested in the opportunity to participate in this cruise searching for these climate-recording organisms far below the surface on FloridaÆs shelf and slope.

Of course, to interpret past ocean conditions, we need to know something about chronology. My current research uses a combination of radiocarbon and uranium series dating to ascertain the age of a skeleton and how long ago its ambient water mass was located at the surface of the ocean. Performing this exercise at different locations gives us an idea of how past circulation patterns from the surface to the subsurface have compared to those that modern-day oceanographers measure. This research is of interest to many as the debate about the effects of global climate change becomes a larger part of the public conscience. My research will undoubtedly benefit from interactions with scientists of the diverse backgrounds found on this cruise and hopefully my findings will be of benefit or interest to them.

	CRUISE ESSAYS What is a Natural Product? - Amy Wright To most people, a "natural product" is probably anything made by nature. To the chemists on this expedition, it is a very special type of "product". To us, natural products, which we also call "secondary metabolites", are low molecular weight (small) compounds which are synthesized (made) by a plant , microorganism or animal which are not essential to sustain life, but which presumably confer an evolutionary advantage. What exactly does this mean? All cells are made up of chemical compounds. If you watch TV or read magazines, you've probably see advertisements that talk about things called "cholesterol", "lipids", "fats", "protein", "sugars", "triglycerides", etc.. All of these things are chemical compounds that are essential to maintain healthy cells and ultimately healthy people. (Its only when the levels are too high or too low that they cause disease- you have to have all of them to be healthy). Substances such as lipids make up the cell membrane. Proteins such as actin and tubulin give the cells shape. Other proteins (enzymes) carry out chemical reactions within the cell. All of these types of chemical compounds (proteins, lipids, triglycerides, sugars, cholesterol, polysaccharides, amino acids, etc.) must be present to allow the cellular machinery to work. Without these substances, which we call "primary metabolites", the individual cells and thus the organism can not survive. In contrast, cells or organisms which lack "secondary metabolites" or "natural products" can survive and reproduce. The compounds do not serve an essential function, e.g. they don't make up the cell membrane, or run chemical reactions. They simply aren't essential to the organism. It takes a lot of energy to make a secondary metabolite. You can think of it as similar to making a cake. Someone has to work to get the money to make a cake, it doesn't come for free. You have to spend money (resources) to buy the ingredients, you have to buy or rent an oven and then you have to pay the electric bill to run the oven. You also have to mix up the ingredients which takes physical energy. All of that energy is used up for something that tastes good, but which you really don't have to have. It is a similar situation for the organism which makes a natural product. It takes a lot of energy to do it, so, why do the organisms bother? In order to understand this better, we need to look at the how these animals grow and the habitats in which they live. During the present expedition we will be working primarily with invertebrates such as soft corals, sponges, bryozoans and ascidians, so we will focus on these. If you look at most reefs you can see that almost every square inch of space is inhabited. Competition for space and food is enormous. Most of the animals are sessile as adults. That means that just like a plant growing in your yard, if something comes by to eat them, they can't get up and run. There are a few invertebrates, such as nudibranchs which can move around, but they really wouldn't set any Olympic speed records. Fish are hundreds of times faster than nudibranchs. As larvae, most of these invertebrates can get around, but once they are ready to metamorphose into adults, they select a home, settle out, metamorphose into a juvenile and if they chose a good spot, they might be able to grow into adults. In general, they can't get up and move if the neighborhood gets bad. This presents a number of interesting problems: - How can they defend themselves against things that want to eat them? - How can they keep other animals from moving into their space? - How can they find a mate if they can't go looking? - How can they protect themselves from bacterial, fungal or viral infections? One way is to accomplish all of these tasks is to use secondary metabolites. If you taste bad, or smell bad or are even toxic, you might not get eaten. Even if a fish takes a bite out of the sponge, the rest of it can survive, and many fish can eventually learn what to eat and what not to eat. The same applies to keeping the neighbors from moving in on you. Most of these animals are filter feeders and so compete with each other for the same food source. It makes sense to keep the neighbors away. Some of these animals even go so far as to produce toxic compounds such that they can actually kill off neighboring organisms and take over their space. One sponge which we might encounter during the expedition which does this is Siphonodictyon coralliphagum. It bores through coral heads and produces a toxic substance which can kill the coral, allowing it to colonize more space. Reproduction can also be a tough proposition if you can't move around and you live in a water environment. Many of the sessile invertebrates are broadcast spawners. That means that at certain times of the year, they simultaneously release sperm and eggs into the water column. Is it just chance that allows the sperm to find the eggs? For at least one soft coral which lives in Australia, it has been demonstrated that a natural products present in the eggs actually act as sperm attractants. Another role of natural products can be to act as chemical lighthouses to guide the larvae back to the adult organism. The larvae can sense these compounds and actively swim back to the parent, thus insuring that they settle in a habitat which is suitable for them to live in (the right neighborhood). On the opposite side, the compounds can act to stop larvae of other species from settling on top of them. They can do this by making it a "bad neighborhood" (e.g. next door to the land fill) or by actually making it toxic for the other species (would you move into Love canal?). Bacteria, fungi and viruses are all present within marine habitats. Just like people, marine organisms can suffer from infection. Most of these animals have only a primitive immune system, if any at all. Many of the secondary metabolites we encounter are strong antibiotics, antifungal and/or antiviral agents, and this may be another reason why they are produced. For most of the compounds we encounter, we really do not really understand why they are present, but luckily for us, we do not have to understand why they are there, it is enough that they are. Most people encounter natural products every day. Do you drink coffee? The natural product caffeine is present in the beans of both the coffee and cola plants. Caffeine acts as a stimulant in mammalian systems. Many clinically used medicines are natural products. Morphine comes from the opium poppy and is a potent pain reliever. What is a Deep-water Coral Reef? - John Reed Deep-sea coral ecosystems are common off the southeastern U.S. within the Exclusive Economic Zone. These include a variety of high-relief, hard-bottom habitats at numerous sites from the Blake Plateau off North Carolina, southward through the Straits of Florida, and in the eastern Gulf of Mexico. However, only a few have been mapped or have had their benthic and fish resources characterized. Deep-water reefs are sometimes defined as coral banks, coral mounds, bioherms, or lithoherms. In general, deep-water banks occur below the effects of waves and the corals lack symbiotic algae (zooxanthellae). A bioherm is a deep-water coral bank that over centuries has formed a mound of unconsolidated sediment and coral debris and is capped with thickets of coral, such as Oculina or Lophelia whereas lithoherms are high-relief, lithified carbonate mounds, rather than unconsolidated sediment mounds, and also may be covered with thickets of live coral. Based on their physical and biological characteristics, these deep-water coral banks fall within the definition of a coral reef. The dominant corals on deep-water reefs in this region are the azooxanthellate, colonial scleractinian hard corals, Oculina varicosa, Lophelia pertusa, Enallopsammia profunda, Madrepora oculata, and Solenosmilia variabilis. Numerous solitary coral species are also common along with numerous species of calcified hydrozoans (family Stylasteridae), bamboo octocorals (family Isididae), and black corals (order Antipatharia). These reefs provide hard-bottom substrate and habitat for sessile macrofauna including scleractinian corals, octocorals (gorgonians), black corals, and sponges, which in turn provide habitat and living space for a relatively unknown but biologically rich and diverse community of associated fishes, crustaceans, mollusks, echinoderms, polychaete and sipunculan worms, and other macrofauna. The Search for New Antibiotics and Cancer Drugs The overall goal of this program is to discover new antibiotics and new cancer drugs. The discovery of penicillin from the fungi Penicillium chrysogenum in the 1920's with its subsequent development into an extremely useful antibiotic in the 1940's brought a revolution in how we treat bacterial infection. Many antibiotics have been discovered in nature and many are produced by microorganisms. Unfortunately there is an emerging problem as bacteria have developed resistance to existing antibiotics, leaving limited treatment options for what is called multi-drug resistant bacterial infection. In an effort to discover new antibiotics to treat these "superbugs" we are investigating marine microorganisms as the source of new antibiotics. During the expedition, microbiologist Kathleen Janda will begin the process of isolating new microorganisms any one of which may produce a useful new antibiotic. Cancer is not a single disease, but rather many diseases all of which have in common the uncontrolled growth of cells resulting in the disease we call cancer. Modern genomics tools are slowly unraveling the mysteries of what causes different forms of cancer and is suggesting new ways that we can block the progression of the disease. In this project, we are collecting new marine invertebrates and microorganisms that we hope will contain new natural products that will allow us to stop cancer. After the expedition, extracts from the organisms we have collected will be tested to see whether they contain compounds that can reverse the processes that have turned normal cells into cancer cells, or alternatively selectively kill only cancer cells. Extraction - First Step Towards Biological Screening The Chemists on the expedition will prepare extracts of each of the organisms we collect. Once we return to the laboratory at HBOI, these extracts will be used in our biological screening program. What is an "Extract"? If you drink tea or coffee, you are familiar with the extraction process. For these drinks, we pour boiling hot water over dried and ground up tea leaves or coffee beans. The hot water "extracts" out the various chemicals (Flavorings and natural products such as caffeine) which are present in the dried plant tissue, creating a good tasting beverage. On the ship, we prepare extracts of the plants and invertebrates we collect by grinding them up in a high speed blender in the presence of ethyl alcohol. We use alcohol rather than hot water, because some of the compounds present in our samples are not stable to treatment with boiling hot water. After trying out lots of different organic solvents, we found that ethyl alcohol also provides us with excellent extraction efficiency while also being safe for both the chemist handling it and the cells and enzymes we eventually use to test these extracts. Gleaning Clues to Climate Change from Deep-water Sponges and Corals - Brad Rosenheim My research involves the use of accretionary skeletons like those deposited by certain corals and sponges to interpret the conditions under which they formed. This is done geochemically. Using a combination of chemical theory and environmental calibration, past research has established relationships between the chemical signatures in these skeletons and the ambient environment around the organism as it lived. In organisms that preserve older portions of skeleton while building new skeleton, this type of knowledge becomes very important. Whereas modern day oceanographers can sail the world (well, most of it) and directly measure temperature, salinity, and currents of the ocean, "paleoceanographers" are left with only proxies of these parameters to elongate our short instrumental record. My work has involved calibrating species of sclerosponges that live deeper than most massive corals for paleoclimate reconstruction and comparing those records to both shallow and deep sea corals. This gives us a better idea of where heat, which is acquired and given off by the ocean at the surface, is transported on the subsurface. Thus I am very interested in the opportunity to participate in this cruise searching for these climate-recording organisms far below the surface on FloridaÆs shelf and slope. Of course, to interpret past ocean conditions, we need to know something about chronology. My current research uses a combination of radiocarbon and uranium series dating to ascertain the age of a skeleton and how long ago its ambient water mass was located at the surface of the ocean. Performing this exercise at different locations gives us an idea of how past circulation patterns from the surface to the subsurface have compared to those that modern-day oceanographers measure. This research is of interest to many as the debate about the effects of global climate change becomes a larger part of the public conscience. My research will undoubtedly benefit from interactions with scientists of the diverse backgrounds found on this cruise and hopefully my findings will be of benefit or interest to them.