DefenseMechanisms: Difference between revisions
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* Toxins | * Toxins | ||
** | ** Relatively harmless to humans | ||
*** Exception: Fire coral – contain a cocktail of toxins than can cause pain, inflammatory effects | |||
** Most toxins are neurotoxins | ** Most toxins are neurotoxins | ||
*** Interfere with signal transmission in animals’ nervous systems | *** Interfere with signal transmission in animals’ nervous systems | ||
*** Three main types | *** Three main types of toxins, all neurotoxic in origin | ||
**** Saxitoxin – causes paralysis and respiratory failure <ref> Ferrer, Ryan P., and Richard K. Zimmer. "Neuroecology, Chemical Defense, and the Keystone Species Concept." The Biological Bulletin 213.3 (2007): 208-25. Print.</ref><ref>Marcus, Erin N. "Marine Toxins." Marine Toxins. Ed. James F. Wiley, II. UpToDate, Inc., 17 Dec. 2012. Web. 27 Feb. 2013.</ref> | **** Saxitoxin – causes paralysis and respiratory failure | ||
***** Produced by a dinoflagellate | |||
***** Sodium channels are blocked, which quickly prevents sodium ions from channels where they need to be <ref> Ferrer, Ryan P., and Richard K. Zimmer. "Neuroecology, Chemical Defense, and the Keystone Species Concept." The Biological Bulletin 213.3 (2007): 208-25. Print.</ref><ref>Marcus, Erin N. "Marine Toxins." Marine Toxins. Ed. James F. Wiley, II. UpToDate, Inc., 17 Dec. 2012. Web. 27 Feb. 2013.</ref> | |||
**** Palytoxin - causes kidney, respiratory and heart failure | **** Palytoxin - causes kidney, respiratory and heart failure | ||
***** Produced by a dinoflagellate | |||
***** Acts on the sodium/potassium antiporters that control cell membrane activity essential for proper functioning of the kidneys and red blood cells | |||
***** So potent that a dose large enough to kill an adult human is invisible to the human eye | |||
**** Lophototoxin – causes muscle contractions, possibly paralysis and respiratory failure | **** Lophototoxin – causes muscle contractions, possibly paralysis and respiratory failure | ||
***** Blocks the connections, or synapses, where nerves connect with muscles | |||
***** Disruption of these receptors causes muscle contractions | |||
* Symbiotic Relationships | * Symbiotic Relationships | ||
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*Nematocytes | *Nematocytes | ||
**Stinging cells used to capture small prey, kill | **Stinging cells used to capture small prey, kill off neighboring corals in a continuous battle for space | ||
**Most corals possess these in addition to everything else | **Most corals possess these in addition to everything else | ||
Revision as of 22:17, 15 April 2013
Defense Mechanisms
The Importance of Defense Mechanisms[1][2]
- Corals are sessile
- Fixed at a certain position, attached to a substrate (such as a rock, or between sand)
- Corals are sessile, colonial animals — remaining stationary for most of their life cycle — which makes the ocean a very dangerous place
- Their vulnerability has lead to some of the most lethal toxins found in nature today
- chemical defense is vital
- Toxicity was naturally selected for
- Corals that were often preyed upon by fish now have higher toxicity levels, for their own protection
- The low nutritional value of some corals made them less susceptible to predation, so the lower the nutritional value, the lower the toxicity level
Chemical Defense Mechanisms [3]
- Toxins
- Relatively harmless to humans
- Exception: Fire coral – contain a cocktail of toxins than can cause pain, inflammatory effects
- Most toxins are neurotoxins
- Interfere with signal transmission in animals’ nervous systems
- Three main types of toxins, all neurotoxic in origin
- Saxitoxin – causes paralysis and respiratory failure
- Palytoxin - causes kidney, respiratory and heart failure
- Produced by a dinoflagellate
- Acts on the sodium/potassium antiporters that control cell membrane activity essential for proper functioning of the kidneys and red blood cells
- So potent that a dose large enough to kill an adult human is invisible to the human eye
- Lophototoxin – causes muscle contractions, possibly paralysis and respiratory failure
- Blocks the connections, or synapses, where nerves connect with muscles
- Disruption of these receptors causes muscle contractions
- Relatively harmless to humans
- Symbiotic Relationships
- Nematocytes
- Stinging cells used to capture small prey, kill off neighboring corals in a continuous battle for space
- Most corals possess these in addition to everything else
Physical Defense Mechanisms
- Cnidocils
- Activated when a predator touches it
- Discharges a nematocyst
- Nematocysts [9]
- Discharge by firing a barb into the predator, leaving a hollow filament through which poisons are injected to immobilize the prey
- Tentacles move the prey to the polyp mouth
Notes
- ↑ "NOAA's Coral Reef Information System (CoRIS) - About Coral Reefs." Coral Ecosystem Publications RSS. National Oceanic and Atmospheric Administration, n.d. Web. 27 Feb. 2013.
- ↑ Van Der Weijden, Sander. "Chemical Defense Mechanisms." Chemical Defense Mechanisms. Coral Publications, n.d. Web. 27 Feb. 2013 [1]
- ↑ Chemical Defense Mechanisms on the Great Barrier Reef, Australia – Gerald J. Bakus. Science. New Series, Vol. 211, No. 4481 (Jan. 30, 1981). pp. 497-499
- ↑ Ferrer, Ryan P., and Richard K. Zimmer. "Neuroecology, Chemical Defense, and the Keystone Species Concept." The Biological Bulletin 213.3 (2007): 208-25. Print.
- ↑ Marcus, Erin N. "Marine Toxins." Marine Toxins. Ed. James F. Wiley, II. UpToDate, Inc., 17 Dec. 2012. Web. 27 Feb. 2013.
- ↑ Rosenberg, Eugene, Omry Koren, Leah Reshef, Rotem Efrony, and Ilana Zilber-Rosenberg. "The Role of Microorganisms in Coral Health, Disease and Evolution." Nature Reviews Microbiology 5.5 (2007): 355-62. Print.
- ↑ Lema, Kimberley A., Bette L. Willis, and David G. Bourne. "American Society for MicrobiologyApplied and Environmental Microbiology." Corals Form Characteristic Associations with Symbiotic Nitrogen-Fixing Bacteria. American Society for Microbiology, 17 Feb. 2012. Web. 27 Feb. 2013.[2]
- ↑ *Stewart, Hannah L., Sally J. Holbrook, Russell J. Schmitt, and Andrew J. Brooks. "Symbiotic Crabs Maintain Coral Health by Clearing Sediments." Coral Reefs 25.4 (2006): 609-15. Print.[3]
- ↑ Kass-Simon, G., and A.A. Scappaticci, Jr. "The Behavioral and Developmental Physiology of Nematocysts." Canadian Journal of Zoology 80.10 (2002): 1772-794. Print.