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Chemistry Stinks! And How Nature Uses These Noxious Chemicals
Download slides after webinar: http://acswebinars.org/wood
Contact ACS Webinars™at acswebinars@acs.org
ACS WEBINARS™January 26, 2012
Darren Griffin, University of Kent
William Wood, Humboldt State
University
Chemistry Stinks!And How Nature Uses These
Noxious Chemicals.
William Wood
Department of Chemistry
Humboldt State University
Arcata, California
Jan. 26, 20126
2/7/2012
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Chemical Ecology
• Pheromones
• Allomones
• Kairomones
Study of how living organism use chemicals to convey messages.
7
AllomonesChemical messages between members of different species
that benefit the sender. (Attraction or Defense)
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Skunk Species in North America
1. Striped Skunk (Mephitis mephitis)
2. Hooded Skunk (Mephitis macroura)
3. Western Spotted Skunk (Spilogale gracilis)
4. Eastern Spotted Skunk (Spilogale putorius)
5. Hog-nosed Skunk (Conepatus mesoleucus)
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Striped Skunk (Mephitis mephitis)
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Hooded Skunk (Mephitis macroura)
Photograph - J. Dragoo 11
Sample of Skunk Spray
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Thomas Aldrich, 1896, 1897
• Investigated skunk defensive secretion as a possible anesthetic.
• Odor threshold of skunk spray determined at 10 ppb.
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Thomas Aldrich, 1896, 1897
1. An Isomer of 1-Butanethiol
CH3CH2CH2CH2SH
2. Other Mercaptans (Thiols)
3.N CH3
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Andersen & Bernstein 1975
1-Butanethiol (butyl mercaptan) was mistakenly incorporated into the chemical literature by the 1930s as the odoriferous compound in skunk spray.
In 1975 this was shown to be incorrect.
CH3CH2CH2CH2SH
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Andersen & Bernstein 1975
C CH
H
CH2SH
CH3
C CH
H
CH2SSCH3
CH3
CH3CHCH2CH2SH
CH3
(structure incorrectly assigned)16
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Striped & Hooded SkunkThiols and Thioacetates
C CH
H
CH2SH
CH3C C
H
H
SCCH3
CH3 O
CH3CHCH2CH2SH
CH3
CH3CHCH2CH2SCCH3
CH3 O
Wood 1990Wood, Sollers, Dragoo & Dragoo 2002
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Striped & Hooded SkunkAlkaloids
N CH2SH N CH2SCCH3
O
N CH3
Wood 1990
Wood, Sollers, Dragoo & Dragoo 2002 18
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Spotted Skunk (Spilogale gracilis)
Photograph - J. Dragoo 19
Spotted Skunk (Spilogale gracilis)
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Spotted Skunk Thiols(No Thioacetates!)
C CH
H
CH2SH
CH3
CH3CHCH2CH2SH
CH3
CH2CH2SH
Wood, Morgan and Miller 199121
Spotted Skunk Alkaloids
N CH2SH N CH3
Wood, Morgan and Miller 1991
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Hog-nosed Skunk (Conepatus mesolucas)
Photograph - J. Dragoo23
Hog-nosed Skunk(A Single Thiol and Thioacetate)
C CH
H
CH2SH
CH3C C
H
H
SCCH3
CH3 O
not in secretion
Wood, Fisher and Graham 1993
CH3
CH3CHCH2CH2SH
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Hog-nosed Skunk Alkaloids
N CH2SH N CH3
Wood, Fisher and Graham 1993
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How do the components work?
1. Thiols - They stink, are lachrymators
and cause nausea.
2. Thioacetates - Decompose to thiols
and make the spray long-lasting.
3. Alkaloids - Do they taste bitter?
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Deodorizing Skunk SprayThe Tomato Juice Myth
Experiment
1. Add skunk spray to tomato juice.
2. Smell mixture - result “skunk odor.”
3. Smell again - result no “skunk odor” only
“tomato juice odor.” DID IT WORK?
4. Smell mixture after 1 hour - result “skunk odor.”
Conclusion: Olfactory fatigue responsible for myth.27
Deodorizing Skunk Spray Pets(Paul Krebaum’s Recipe)
1. 1 Quart of 3% Hydrogen Peroxide
2. 1/4 Cup of Baking Soda
3. 1 Tsp. of Liquid Detergent
--Use Immediately--
--No Closed Container!--
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Skunks Are AggressiveSpray Used Only In Defense
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Phylogenetic Implications
Ancestral Skunk
MephitisSpilogale
Conepatus
Thiols andThioacetates Thiols but no
Thioacetates
Only one Thioland Thioacetate
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Garter Snake Defensive Secretion
CH3CHCH2CO2H
CH3
CH3CH2CH2CO2H
CH3CHCO2H
CH3
CH3CH2CO2H
CH3CO2H
Short-Chain Carboxylic Acids
CH3
N
CH3
CH3
Trimethylamine
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Garter Snake Defensive Secretion
RCO
O
HN
CH3
H3C
CH3
acid
base
R C O
O
H
salt (pH =7)
N
CH3
H3C
CH3
Wood, Parker & Weldon 1995
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Wolverine Defensive Secretion
CH3CHCH2COH
CH3 O
CH3CH2CHCOH
CH3
OCH2COH
O
Wood, Terwilliger and Copeland 200536
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CH3(CH2)6CH3
CH3(CH2)5CHO
CH3(CH2)6CHO
CH3(CH2)7CHO
OH
CH3
Alkane
Aldehydes
Aromatics
N
H
N
H
CH3
Fatty Acids
OH
O
OH
O
Wood and Weldon 2002 38
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Chemical in the Devil’s Tongue
NH
Indole (Feces)
CH2CH2OH
Phenethyl Alcohol (Roses)
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Pheromones
Chemical messages between members of the same species.
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Long-tailed Weasel
Scent markswith anal gland secretion.
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Thiatanes in Anal Secretion
SCH3CH3
S
CH3
CH3
SCH2CH2CH3
SCH3
CH3
Wood and Joest 200844
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Dithiolanes in Anal Secretion
SS
CH3
CH3 SS
CH2CH3
Wood and Joest 2008
45
Indole and 2-Aminoacetophenone
N
H
C
O
CH3
NH2
Wood and Joest 200846
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Chemical Ecology Review
Pheromones - Chemical messages between members of the same species.
Allomone - Chemical messages between members of different species that benefits the sender.
Kairomone - Chemical messages between members of different species that benefit the
receiver. 47
The End You Don’t Want To See
48
Recommended