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

Circadian Clocks (cont.)

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 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 C 22 H 19 Br 2 NO 3

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 = mg  Average mass of male = mg

Dose Response Data

Two Hour Interval Test Data

Csp and Per-Null Testing Data

GST Assay Data

Future Investigations  I will continue working on investigating direct toxin applications and GST assays throughout the school year at Oregon State University

Acknowledgements  Howard Hughes Medical Institute  URISC  Dr. Kevin Ahern  Dr. Jadwiga Giebultowicz  Everyone in the lab