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Circadian Susceptibility to Circadian Susceptibility to Pyrethroids in Female Pyrethroids in Female
Drosophila melanogasterDrosophila melanogasterBy David ChinBy David Chin
Mentor: Dr. Jadwiga Giebultowicz
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Relevance for ResearchRelevance for ResearchHow fruit flies metabolize toxins may How fruit flies metabolize toxins may
be:be:Different between males and femalesDifferent between males and femalesRelated to how humans metabolize Related to how humans metabolize
toxins via circadian rhythmstoxins via circadian rhythmsThese links may open up new These links may open up new
inquiries in pharmaceuticals, inquiries in pharmaceuticals, horticulture, and global economicshorticulture, and global economics
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Circadian RhythmsCircadian Rhythms Internal clocks Internal clocks
that control when that control when organisms rest organisms rest and remain activeand remain active I.e. Jet lag… … … I.e. Jet lag… … … Controlled by the Controlled by the
Period and Tim Period and Tim genesgenes
http://edfredned.com/images/portfolio/Full/jetlag.gif
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Circadian Clocks (cont.)Circadian Clocks (cont.)
http://www.ou.edu/wanglab/Circadianclock1/Slide1.jpg
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Circadian Rhythms (cont.)Circadian Rhythms (cont.)Physiologically, they influence:Physiologically, they influence:
Hormone secretionHormone secretionOxygen consumptionOxygen consumptionMetabolismMetabolismOther functions of the bodyOther functions of the body
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Point of InterestPoint of InterestCircadian rhythms may influence the Circadian rhythms may influence the
rate of metabolism of many rate of metabolism of many substances, including toxinssubstances, including toxins
The pyrethroid, deltamethrin, is The pyrethroid, deltamethrin, is administered to the female flies to administered to the female flies to investigate how they metabolize investigate how they metabolize toxins in relation to the presence and toxins in relation to the presence and absence of the circadian rhythmabsence of the circadian rhythm
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PyrethroidsPyrethroids Synthetic Synthetic
insecticides insecticides derived from the derived from the flowers of flowers of pyrethrums or pyrethrums or several plants from several plants from the genus the genus ChrysanthemumChrysanthemum http://upload.wikimedia.org/wikipedia/
commons/f/fa/Chrysanthemums.jpg
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DeltamethrinDeltamethrin Deltamethrin is a pyrethroid insecticide that Deltamethrin is a pyrethroid insecticide that
damages the nervous system, paralyzing the damages the nervous system, paralyzing the organisms after cuticular penetration or oral organisms after cuticular penetration or oral uptake of the neurotoxinuptake of the neurotoxin
http://upload.wikimedia.org/wikipedia/commons/3/3f/Deltamethrin-3D-balls-2.png
C22H19Br2NO3
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Deltamethrin (cont.)Deltamethrin (cont.)Modifies the membrane function Modifies the membrane function
proteins and keeps the voltage-proteins and keeps the voltage-dependent sodium channels dependent sodium channels continuously opencontinuously open
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Flies Being TestedFlies Being TestedCS Flies = Wild type flies with Period & CS Flies = Wild type flies with Period &
Tim genesTim genesPer-null Flies = Mutant flies that lack Per-null Flies = Mutant flies that lack
the Period gene expressionsthe Period gene expressionsCsp Flies = Backcrossed flies that Csp Flies = Backcrossed flies that
express the Period & Tim genes and are express the Period & Tim genes and are closely related to the Per-null fliesclosely related to the Per-null flies
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ExperimentsExperimentsDose ResponseDose ResponseTwo Hour Interval TestTwo Hour Interval TestGST AssayGST Assay
Glutathione S-Transferases take part in Glutathione S-Transferases take part in metabolizing toxins metabolizing toxins
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Mass Ratio DataMass Ratio DataAverage mass of female = 1.409 mgAverage mass of female = 1.409 mgAverage mass of male Average mass of male == 0.8103 mg 0.8103 mg
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Dose Response DataDose Response DataDeltamethrin EC50
Female Male0
50
100
150 137 μg/μ l
20 μg/μ l
EC50
Deltaμethrin [
μg/μl]
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Two Hour Interval Test DataTwo Hour Interval Test DataFemales
0 2 4 6 8 10 12 14 16 18 20 220
20
40
60
80
100
Time (ZT Hours)
Mortality (%)
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Two Hour Interval Test DataTwo Hour Interval Test DataMales
0 2 4 6 8 10 12 14 16 18 20 220
20
40
60
80
100
Time (ZT Hours)
Mortality (%)
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Csp and Per-Null Testing DataCsp and Per-Null Testing DataPeak and Trough Test Data in Mortality
9 pm 7am 9 pm 7am0
20
40
60
80
100
Csp Per-Null
Mortality (%)
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GST Assay DataGST Assay DataFemales
0 2 4 6 8 10 12 14 16 18 20 220
20
40
60
80
100
Time (ZT Hours)
Mortality (%)
GST Assay (Basal Activity in Females)
7 pm 9 pm 5 am 7 am0
10
20
30
40
Cs
GST Activity (nmol/min/mg)
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GST Assay DataGST Assay DataMales
0 2 4 6 8 10 12 14 16 18 20 220
20
40
60
80
100
Time (ZT Hours)
Mortality (%)
GST Assay (Basal Activity in Males)
7 pm 9 pm 5 am 7 am0
10
20
30
40
CS
GST Activity (nmol/min/mg)
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Future InvestigationsFuture Investigations I will continue working on I will continue working on
investigating direct toxin applications investigating direct toxin applications and GST assays throughout the and GST assays throughout the 2007-2008 school year at Oregon 2007-2008 school year at Oregon State UniversityState University
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AcknowledgementsAcknowledgementsHoward Hughes Medical InstituteHoward Hughes Medical InstituteURISCURISCDr. Kevin AhernDr. Kevin AhernDr. Jadwiga GiebultowiczDr. Jadwiga GiebultowiczEveryone in the labEveryone in the lab