More of our class explores Lighthouse Cave, San Salvador, Bahamas.
When you think about new advances in medicine where do you think they come from; the lab, made artificially by chemicals. This is what the majority of people that I talk to think. Most people think the only way we get useful drugs are through manipulating chemicals. Although this is where we get a large number of medications, it’s not where all medicines or therapies come from. From the beginning of man, we have used nature to help heal our ailments. Whether it is chewing on a root to help cure a headache or mixing herbs together and boiling it to cure a cold, man and nature have worked together until technology took over the world. Researchers have found a ton of new medicine in the Rainforest. They attribute this to the amount of biodiversity in this ecosystem. What about an area untouched due to its location but with more biodiversity than the rainforests? Coral reefs over the past decade have been studied in search for their medical resources. Eastern cultures have been using the coral reefs for their medicinal properties ever since the 14th century.
In this paper I will address different examples of how coral reefs have been able to help medicine, the problems that coral reefs face, and possible solutions to these problems.
The coral reef is home to so many diverse creatures especially when compared to a terrestrial ecosystem, that the prospect of finding a new drug here may be 300 to 400 times more likely than on land. Coral reefs are home to similar fungi and other sessile plants, but it is the diverse collection of invertebrates (mollusks, sponges, tunicates, etc…) that are missing from the terrestrial ecosystem that makes it so promising. Most of these animals “…spend most of their time firmly attached to the reef and cannot escape environmental perturbations, predators, or other stressors. Many engage in a form of chemical warfare, using bioactive compounds to deter predation, fight disease, and prevent overgrowth by fouling and competing organisms…” (Brucker). It is these unique properties and compounds that may lead to life-saving medicines. A couple of small examples are the collection of sea hare. With this scientists have isolated a compound used to fight melanoma, called Dolostain 10. It took 1,600kg of sea hare to isolate 10mg of the compound. Others have collected an Indo-Pacific sponge to produce and anticancer compound, called Ara-A, AZT, and Ara-C. It took 2,400kg of the sponge to produce 1 mg of the compound. There are also advances in cancer therapies made from algae and a painkiller from the venom of cone snails. At least 1 kg of each compound may be required for drug development.
For centuries the cone snail was sought after for its beautiful shell, but now they have found use in the different immobilizing toxins found in them. The main toxins are conotoxins. These can mediate heart rate and contractility, as well as skeletal muscles and brain. They can also be useful in controlling potassium and sodium ion channels. “In small-cell lung cancer, activation of nicotinic acetylcholine receptors and voltage-dependent calcium channels in tumor cell membranes promotes tumor cell proliferation. Conotoxins that block these activation receptors and ion channels, and that bind to antibodies that form to attack them, may be effective in early detection and perhaps also in treatment of this devastating cancer. One synthetic conotoxin is in Stage III clinical trials for treatment of intractable pain” (Science).
The Pacific yew is and old-growth tree that is the source of a compound called taxol. Taxol has been proven in clinical trials to induce remission in ovarian cancer. This compound has a unique way of killing cancer. It inhibits the disassembly of the mitotic spindle. Since the discovery of taxol several taxol-like medicines have been produced and scientists are hopeful that they will be useful when treating both breast and ovarian cancer. Over-logging of these Pacific yews does pose a threat to future research.
An animal that has been recently been studied for its medical use is sharks. Sharks produce powerful infection/cancer fighting molecules in their tissues that give them a boost in immune response. One substance being studied is called aminosteroid, a.k.a. squalamine. When tested in rats it has lowered infection rate and lessened tumors. Scientists believe that the reason why this compound has been so effective in reducing solid tumors is because it has an “angiogenesis-inhibiting ability”, and has been proven to be an antibiotic against both gram-negative and gram-positive bacteria. But over fishing of sharks for their fins and cartilage definitely endangers the hope of further research.
There is also a compound that can be taken from different Caribbean sponges to help fight cancer. Cytarabine is said to be the “single most effective agent for inducing remission in acute myelocytic leukemia” (Chivian). There have been many studies testing Cytarabine. They have found that it is useful in post-remission therapy but not as an initial induction treatment. One study used humans ranging for ages 15-60, those have been diagnosed with acute myelocytic leukemia and had no prior chemotherapy treatments. All groups were randomized to receive different amounts of cytarabine. All groups followed the same schedule of treatments and had the same post-induction consolidation therapy. There were problems that occurred in the higher doses to cytarabine including; nausea, vomiting, eye toxicity, and different complications with the central nervous system. But overall they did find that it does induce remission and prolong a disease free life.
Knowing the medical uses of coral reefs, why aren’t we doing more to protect it? Three of the main problems that are endangering coral reefs are pollution, tourism, and over harvesting. Pollution is one of the biggest problems facing coral reef destruction. It is said that if emission levels aren’t controlled and water pollution stopped then 70% of the world’s coral reef will be depleted within the next decade. Global warming causes Coral Bleaching, this is when the microscopic organisms, known as zooxanthellae, become stressed and leave the coral. Zooxanthellae give the coral its color and provide it with essential nutrients, which without the coral die. As far as the problems that tourism brings to the Reef, the Florida Keys hosts several million divers, snorklers, and fishing boats every year. Florida is the number one dive destination in the world. It has ten times the number of the second highest rated diving area, which is Australia, an area of reef ten times larger. At this rate tourist wont have do be concerned with visiting the coral reef, because nothing will be left to see. And finally over harvesting affects the medical field as well as the balance of the reef system. There has been much research in the reefs to show hope for the medical field. But in order for it to be helpful to medical science it must be a renewable resource. And as we have just learned, it takes so much of an organism to extract just one kg of the substance that we could easily make a species become extinct. For example, the cone snail population has been decreasing at an alarming rate ever since scientists have discovered its usefulness in cancer research.
There are things that we can do to protect the coral reef and still enjoy the wonder of them. First of all, the government needs to have tighter control on the amount of emissions into the air. They also need to hold companies and people accountable for polluting our oceans. Everyone needs to be aware of the world around them and just how delicate the web of life really is. Second, there needs to be a way to regulate how many people visit the reefs per year or something along those lines. It is sad to me to think that I could unknowingly be destroying something I enjoy just by visiting it. I believe that most people who really love the reef would understand if there were regulations put on the tourists. And finally the over harvesting problem can be solved through science. If a new compound is found, I feel that the scientists should create synthetic versions of these. This way everything will be as it should and we are still able to make medical advances. Bottom-line; it is up to us to preserve the earth and use what we need wisely. Now that we know what the problem is, it is very irresponsible for us to sit back and do nothing.
• Bishop, JF. A randomized study of high-dose cytarabine in induction in acute myeloid leukemia. Australian Leukemia Study Group, Peter MacCallum Cancer Institute, Melbourne, Australia. PMID: 8634416
• Byrd, John C. Patients With t(8;21)(q22;q22) and Acute Myeloid Leukemia Have Superior Failure-Free and Overall Survival When Repetitive Cycles of High-Dose Cytarabine Are Administered. Journal of Clinical Oncology, Vol 17, Issue 12 (December), 1999: 3767-3775.
• Caley, M. J. Predation, recruitment and the dynamics of communities coral-reef fishes. Marine Biology. Volume 117, Issue Number 1 pages: 33 – 43
• Chivian, Eric. Environment and health: 7. Species loss and ecosystem disruption — the implications for human health. Environment and Health series. CMAJ 2001;164(1):66-9.
• Ehrlich PR, Wilson EO. Biodiversity studies: science and policy. Science 1991;253:758-62.
• Glynn, P.W. Coral reef bleaching: ecological perspectives. Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric ScienceMiami, Florida. June 19, 1992.
• Knowlton, Nancy. Thresholds and Multiple Stable States in Coral Reef Community Dynamics. Smithsonian Tropical Research Institute Apartado 2072, Balboa, Ancon, Republic of Panama.
• McClamahan, T.R. Causes and consequences of sea urchin abundance and diversity in Kenyan coral reef lagoons. Oecologia. Volume 83, Issue Number 3. pg 362-370.
• Wiernik, PH. Cytarabine plus idarubicin or daunorubicin as induction and consolidation therapy for previously untreated adult patients with acute myeloid leukemia. Volume 79, Issue 2, pp. 313-319, 01/15/1992. The American Society of Hematology. 199
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