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The Biology of Chemical Defense

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Objectives

• Explain why animals use chemicals for defense• Describe how do organisms get these chemicals• Explain how the blue-ringed octopus uses its

neurotoxin? How does the neurotoxin work?• Understand symbiotic relationships• Explain how whip scorpions are protected from their

chemical defense• Understand pheromones• Know the 3 groups of aniherbivory compounds• Understand how alkaloids affect organisms• Explain how non protein amino acids kill organisms• Give examples of human uses for chemical defense

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Key Terms

• Neurotoxin

• Pheromone

• Aposematic

• Ion Channel

• Symbiosis

• Acetic acid

• Fatty Acid

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How do most animals defend themselves?

• Large teeth (shark)

• Large size (elephant)

• Sharp claws (tiger)

• Fast speed (antelope)

• Excellent camouflage (chameleon)

• What if you don’t have any of these?

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Chemical Defense!

• Some animals and plants use chemistry!

• They synthesize the chemicals

or• They accrue the chemicals from their diet

• Many organisms that use chemical defenses are brightly colored as a warning to predators– Aposematic

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The Blue-Ringed Octopus

• Shallow waters in Pacific Ocean

• Neurotoxin from bacteria in body

• Toxin injected by glands near mouth– TTX = Tetrodotoxin

(also in puffer-fish)– TTX “plugs” ion

channel in cells

• One of the most poisonous sea animals

http://www.msmr.org/documents/BFTBToxicology12.pdf

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Clownfish

• Clownfish coexist (symbiotic relationship) with sea anemones

• Sea anemones use tentacles to sting its prey

• Why don’t they sting the clownfish?– Clownfish have evolved

a protective chemical layer of mucus

– Sea anemone and clownfish acclimate to each other

http://en.wikipedia.org/wiki/File:Anemone_purple_anemonefish.jpg

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Whip Scorpion

• Sprays defensive chemicals at enemies– Acetic acid from a gland

in the tail

• How does it protect itself?– Exoskeleton lined with

protective chemicals (fatty acids) that act as solvents if spray gets on the whip scorpion

http://en.wikipedia.org/wiki/File:Whipscorpion.jpg

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Asian Giant Hornet

• World’s largest Hornet– Found in Asia– Kill more people than

snakes in Japan– Pheromone used for

alarm• Alarm pheromone can be

used when nest is under attack

• One scout hornet marks a target with the alarm pheromone

• Remaining hornets aggressively attack the target

http://www.naturenet.net/blogs/media/mandarinia2.jpg

http://en.wikipedia.org/wiki/File:Vespa_mandarinia.jpg

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National Geographic Video:“Hornets from Hell”

http://www.youtube.com/watch?v=DcZCttPGyJ0

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Plants

• Plants have developed chemicals to serve as defenses against herbivores and other dangerous organisms

• These compounds are known as antiherbivory compounds

• Classified into three groups: – Nitrogen Compounds

– Terpenoids

– Phenolics

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Classification of Antiherbivory Compounds

Nitrogen Compounds

- Alkaloids

- Amines

- Non protein amino acids

- Cyanogenic glycosides and Glucosinolates

Terpenes-Monoterpenes

-Cartenoids

Phenols-Simple phenols

-Polyphenols

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Alkaloids

• Alkaloids derived from amino acids : – Ornithine– Lysine– Phenylalanine

• Over 3000+ known– Nicotine– Caffeine

• Effects:– Enzymes– Membranes– Nucleic acids– Nerve induction

http://upload.wikimedia.org/wikipedia/commons/c/c7/Nicotine-2D-skeletal.png

http://upload.wikimedia.org/wikipedia/commons/4/43/Nicotine-3D-vdW.png

Nicotine

Nicotine 3-D

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Non-protein amino acids

• Simplest and most widely present compound

• 300+ known• Usually found in seeds• May be directly toxic or

anti-metabolites. • Resemble amino acids,

these compounds are mistakenly incorporated into protein synthesis– Produce defective

enzymes and kill the organism

http://upload.wikimedia.org/wikipedia/commons/f/f9/Canavanine.png

http://upload.wikimedia.org/wikipedia/commons/f/f4/Arginin_-_Arginine.svg

Arginine

Canavanine

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Terpenes

• Dimers, or combinations of a 5 carbon precursor called isoprene.

• 10,000+ known • Diterpenes are made of 3

to 4 isoprenes:– Poison plant resins

• Glycosides:– Monarch butterflies

store the glycosides they eat from plants to deter birds

– Predators spit out the butterflies and avoid them in the future.

http://www.nature.com/nchembio/journal/v3/n7/images/nchembio.2007.5-F4.jpg

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Phenols

• Contain a fully saturated 6 carbon ring linked to an oxygen

• Produce pigments • Inhibit microorganisms

and seed germination• Lignin fortify and

strengthen plant walls• Act as antioxidants or free

radical receptors – Incredible medicinal

value

Lignin

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Wild Tobacco Plant

• Chemical signal to lure predators to eat leaf-eating insects

• A chemical SOS – Hawkmoth caterpillars

hatch they feed on its leaves

• Leaf-chewing by the caterpillars induces chemical release in tobacco

• Chemicals help predators zero in on the Hawkmoth

• When Hakwmoth detact chemical, they avoid the plant

• Predators are attracted and egg-laying moths are repelled

http://www.mpg.de/english/illustrationsDocumentation/documentation/pressReleases/2001/news0103_bild1.jpg

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Human Chemical Defense?

• We use chemicals too• Pharmaceuticals

– taxol

• Insecticides – nicotine

• Pepper “OC” spray – "Oleoresin Capsicum”– Produced from chilies

and peppers– Non-lethal– Irritant to eyes

http://www.defence.gov.au/Army/8_12mdm/images/101%20Solomons%20(4).jpg

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Summary

• Why do animals use chemicals for defense?• How do organisms get these chemicals?• How the blue-ringed octopus uses its neurotoxin?• How does TTX work?• Why don’t sea anemones sting clownfish?• How does the whip scorpion use chemicals to protect itself? • What is an alarm pheromone?• What are the 3 groups of aniherbivory compounds?• What effect do alkaloids have on organisms?• How do non protein amino acids kill organisms?• How do terpenes protect monarch butterflies?• Identify human uses of chemical defenses?

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Questions?

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References

• Anonymous. 1999. Biochemical defenses: secondary metabolites: Antiherbivory Biochemicals. [Online]; [about 8 screens]. <http://www2.mcdaniel.edu/Biology/botf99/herbnew/aprodbc.htm>

• Anonymous. 2002. Toxicology. Breakfast for the Brain. [Online]; [about 2 screens]. <http://www.msmr.org/documents/BFTBToxicology12.pdf>

• Caldwell, R. 2009. What makes blue-rings so deadly? Blue-ringed octopus' have tetrodotoxin. The Cephalopod Page. [Online]; [about 2 screens]. <http://www.thecephalopodpage.org/bluering2.php>

• Yotsu-Yamashitaa, M., D. Mebsb, and W. Flachsenbergerc. 2007. Distribution of tetrodotoxin in the body of the blue-ringed octopus (Hapalochlaena maculosa). Toxicon. 49(3): 410–412. <http://www.sciencedirect.com.proxy-um.researchport.umd.edu/science?_ob=MImg&_imagekey=B6TCS-4M6RXH6-1-1&_cdi=5178&_user=961305&_orig=browse&_coverDate=03%2F01%2F2007&_sk=999509996&view=c&wchp=dGLbVlb-zSkzS&md5=eecb7d0132dcb1749a0f6498699c314a&ie=/sdarticle.pdf>

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References (1 of 3)

• Fautin, D. and G. Allen. 1992. Field Guide to Anemone Fishes and Their Host Sea Anemones. [Online]; [about 4 screens]. <http://www.nhm.ku.edu/inverts/ebooks/intro.html>

• Anonymous. 2008. Monterey Bay Aquarium. Splash Zone: Coral Reef Animals. [Online]; [one screen]. <http://www.montereybayaquarium.org/efc/efc_splash/splash_animals_clownfish.aspx>

• Schmidt, J., F. Dani, G. Jones, and D. Morgan 2000. Chemistry, ontogeny, and role of pygidial gland secretions of the vinegaroon Mastigoproctus giganteus (Arachnida: Uropygi). Journal of Insect Physiology. 46(4): 443–450. <http://www.sciencedirect.com.proxy-um.researchport.umd.edu/science?_ob=ArticleURL&_udi=B6T3F-3YJYDPV-8&_user=961305&_coverDate=04%2F30%2F2000&_rdoc=9&_fmt=high&_orig=browse&_srch=doc-info(%23toc%234945%232000%23999539995%23160783%23FLA%23display%23Volume)&_cdi=4945&_sort=d&_docanchor=&_ct=25&_acct=C000049425&_version=1&_urlVersion=0&_userid=961305&md5=1026688a6374fb6606f188f84e25feec>

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References (2 of 3)

• Handwerk, B. 2002. "Hornets From Hell" Offer Real-Life Fright. National Geographic News. [Online]; [about 3 screens]. <http://news.nationalgeographic.com/news/2002/10/1025_021025_GiantHornets.html>

• MacLean, C. and E. Schmolz. 2004. Calorimetric investigations on the action of alarm pheromones in the hornet Vespa crabro. Thermochimica Acta. 414 : 71–77. <http://www.sciencedirect.com.proxy-um.researchport.umd.edu/science?_ob=MImg&_imagekey=B6THV-4BFVNKF-9-R&_cdi=5292&_user=961305&_orig=browse&_coverDate=05%2F06%2F2004&_sk=995859998&view=c&wchp=dGLzVtb-zSkWb&md5=b5c4b0b69945e4934e64e4f6e3d99ce4&ie=/sdarticle.pdf>

• Matsuura, M. and S. Sakagami. 1973. A Bionomic Sketch of the giant Hornet Vespa mandarinia, a serious pest for Japanese apiculture. Journal of the Faculty of Science, Hokkaido University. Series 6, Zoology. 19(1): 125-162. <http://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/27557/1/19%281%29_P125-162.pdf>

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References (3 of 3)

• Parry, L. 2005. Killer hornets get a taste for humans. [Online]; [about 2 screens]. Times Online. <http://www.timesonline.co.uk/tol/news/world/article582267.ece>

• Voith, M. 2003. Gee, Your Hair Smells Dangerous. Volatile fragrance chemicals may attract unwanted attention from hornets and bees. [Online]. [about 2 screens]. Chemical and Engineering News. http://pubs.acs.org.proxy-um.researchport.umd.edu/cen/critter/8137hornets.html

• Vesaluoma, M., L. Müller, J. Gallar, A. Lambiase, J. Moilanen, T. Hack, C. Belmonte, and T. Tervo. 2000. Effects of Oleoresin Capsicum Pepper Spray on Human Corneal Morphology and Sensitivity. Investigative Ophthalmology and Visual Science. 41:2138-2147. <http://www.iovs.org/cgi/reprint/41/8/2138>