Circadian Susceptibility to Pyrethroids in Female Drosophila melanogaster By David Chin Mentor: Dr....
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Transcript of Circadian Susceptibility to Pyrethroids in Female Drosophila melanogaster By David Chin Mentor: Dr....
Circadian Susceptibility to Circadian Susceptibility to Pyrethroids in Female Pyrethroids in Female
Drosophila melanogasterDrosophila melanogasterBy David ChinBy David Chin
Mentor: Dr. Jadwiga Giebultowicz
Relevance for ResearchRelevance for Research
How 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
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
Circadian Clocks (cont.)Circadian Clocks (cont.)
http://www.ou.edu/wanglab/Circadianclock1/Slide1.jpg
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
Point of InterestPoint of Interest
Circadian 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
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
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
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
Flies Being TestedFlies Being Tested
CS Flies = Wild type flies with Period & CS Flies = Wild type flies with Period & Tim genesTim genes
Per-null Flies = Mutant flies that lack Per-null Flies = Mutant flies that lack the Period gene expressionsthe Period gene expressions
Csp 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
ExperimentsExperiments
Dose 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
Mass Ratio DataMass Ratio Data
Average 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
Dose Response DataDose Response DataDeltamethrin EC50
Female Male0
50
100
150 137 μg/ml
20 μg/ml
EC50
[Deltamethrin
μ / ]g ml
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 (%)
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 (%)
Csp and Per-Null Testing DataCsp and Per-Null Testing Data
Peak and Trough Test Data in Mortality
9 pm 7am 9 pm 7am0
20
40
60
80
100
Csp Per-Null
Mortality (%)
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)
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)
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