Transcript Drosophila melanogaster Circadian Clocks in response to

Circadian Susceptibility to Pyrethroids in
Female Drosophila melanogaster
By David Chin
Mentor: Dr. Jadwiga Giebultowicz
Relevance for Research
 How
fruit flies metabolize toxins may be:
 Different
between males and females
 Related to how humans metabolize toxins via
circadian rhythms
 These
links may open up new inquiries in
pharmaceuticals, horticulture, and global
economics
Circadian Rhythms

Internal clocks that
control when
organisms rest and
remain active
 I.e.
Jet lag… … …
 Controlled by the
Period and Tim
genes
http://edfredned.com/images/portfolio/Full/jetlag.gif
Circadian Clocks (cont.)
http://www.ou.edu/wanglab/Circadianclock1/Slide1.jpg
Circadian Rhythms (cont.)
 Physiologically,
they influence:
 Hormone
secretion
 Oxygen consumption
 Metabolism
 Other
functions of the body
Point of Interest
 Circadian
rhythms may influence the rate
of metabolism of many substances,
including toxins
 The pyrethroid, deltamethrin, is
administered to the female flies to
investigate how they metabolize toxins in
relation to the presence and absence of
the circadian rhythm
Pyrethroids

Synthetic insecticides
derived from the
flowers of pyrethrums
or several plants from
the genus
Chrysanthemum
http://upload.wikimedia.org/wikipedia/com
mons/f/fa/Chrysanthemums.jpg
Deltamethrin

Deltamethrin is a pyrethroid insecticide that damages
the nervous system, paralyzing the organisms after
cuticular penetration or oral uptake of the neurotoxin
C22H19Br2NO3
http://upload.wikimedia.org/wikipedia/commons/3/3f/Deltamethrin-3D-balls-2.png
Deltamethrin (cont.)
 Modifies
the membrane function proteins
and keeps the voltage-dependent sodium
channels continuously open
Flies Being Tested
 CS
Flies = Wild type flies with Period & Tim
genes
 Per-null Flies = Mutant flies that lack the
Period gene expressions
 Csp Flies = Backcrossed flies that express the
Period & Tim genes and are closely related to
the Per-null flies
Experiments
 Dose
Response
 Two Hour Interval Test
 GST Assay
 Glutathione
S-Transferases take part in
metabolizing toxins
Mass Ratio Data
 Average
mass of female = 1.409 mg
 Average mass of male = 0.8103 mg
Dose Response Data
Deltamethrin EC50
Deltamethrin [ g/ml]
150
137 g/ml
100
50
20 g/ml
0
Female
Male
EC50
Two Hour Interval Test Data
Females
100
60
40
20
Time (ZT Hours)
22
20
18
16
14
12
8
10
6
4
2
0
0
Mortality (%)
80
Two Hour Interval Test Data
Males
100
60
40
20
Time (ZT Hours)
22
20
18
16
14
12
8
10
6
4
2
0
0
Mortality (%)
80
Csp and Per-Null Testing Data
Peak and Trough Test Data in Mortality
100
Mortality (%)
80
60
40
20
0
9 pm
Csp
7am
9 pm
7am
Per-Null
GST Assay Data
40
Females
100
80
30
Mortality (%)
20
10
60
40
20
Cs
Time (ZT Hours)
22
20
18
16
14
12
7 am
8
10
5 am
6
9 pm
4
7 pm
2
0
0
0
GST Activity (nmol/min/mg)
GST Assay (Basal Activity in Females)
GST Assay Data
Males
40
100
80
30
Mortality (%)
20
10
60
40
20
CS
Time (ZT Hours)
22
20
18
16
14
12
7 am
8
10
5 am
6
9 pm
4
7 pm
2
0
0
0
GST Activity (nmol/min/mg)
GST Assay (Basal Activity in Males)
Future Investigations
I
will continue working on investigating
direct toxin applications and GST assays
throughout the 2007-2008 school year at
Oregon State University
Acknowledgements
 Howard
Hughes Medical Institute
 URISC
 Dr.
Kevin Ahern
 Dr. Jadwiga Giebultowicz
 Everyone in the lab