The Effects of Msr A and Msr B

The Effects of Msr. A and Msr. B in Anoxia Tolerance in Aging Drosophila melanogaster Nirthieca Suthakaran Advisor: Dr. David Binninger Dr. Evelyn Frazier

What is Anoxia? • Oxygen deprivation

Dangers of Anoxia Reoxygenation Effect Introducing oxygen back into the system Methionine Oxidation Burst of reactive oxygen species (ROS) Superoxide anion (O 2 -) Hydrogen peroxide (H 2 O 2) Cellular Damage http: //nmr. fli-leibniz. de/nmrprojects. shtml

DROSOPHILA

Methionine Sulfoxide Reductase Reduction Oxidation Reduction

Research Question Does Msr. A and Msr. B play a role in responding to anoxic conditions?

Msr Single Deletion Fly Lines Genotype Msr. A Msr. B WT 60 Present A 90 Not Present B 54 Present Not Present

Research Strategy 1) Individual flies for each genotype were placed into each of the 32 tubes in the Drosophila Activity Monitor (DAM) holder. 2) Flies were placed in the DAM holder for 10 minutes of stabilization 3) Flies were placed into the anoxia tank for 1 hour. 5) Analyzed and averaged the recovery times recorded by the DAM system 4) Flies were placed into the DAM system for 5 hours

Preliminary Data: Longer Recovery Time in Older Aged Flies * * * Legend WT 60: Wild-type control (Msr. A+Msr. B+) A 90: Msr. A Loss of Function (Msr. A-Msr. B+) B 54: Msr. B Loss of Function (Msr. A+Msr. B-) AB 46: Msr Double Loss of Function (Msr. A-Msr. B-) * *

Research Question #1 Will Msr single LOF mutant flies show increased susceptibility to anoxia as they approach senescence (60 -65 days)? Aging: 20 -25 days (young age) 40 -45 days (middle age) 60 -65 days (old age) 32 flies 10 min Normoxia 32 flies 1 hour Anoxia 32 flies 1 hour anoxia + 5 hours Reoxygenation

Single Deletion Line Results The WT 60 line recover significantly later as they approach senescence, while the Msr. A and Msr. B mutants reach maximum recovery time at middle age (4045 days old). A. B. C.

Research Question #2 Does a knock down of the single LOF Msr genes via RNAi show increased susceptibility to anoxia as they approach senescence (60 -65 days)? RNAi lines: UAS-Gal 4 system Main Driver Used: Actin Driver http: //www. nature. com/nrg/journal/v 3/n 3/box/nrg 751_BX 2. html

Creating RNAi Lines

Results for RNAi Lines The RNAi-A and RNAi-B knockdown lines reach maximum average recovery time after anoxic stress at middle age (40 -45 days old). A. B. C. * * *

Summary & Significance • The Msr. A+Msr. B+ (WT 60) line recovers significantly later as the flies approached senescence (60 -65 days old). • The Msr. A and Msr. B single deletion mutants reach maximum recovery time at middle age (40 -45 days old). • Unexpectedly, the 60 -65 day old Msr. A and Msr. B single deletion lines recover faster than the 40 -45 day old single deletion lines and are indistinguishable from the Msr. A+Msr. B+ (WT 60) line.

Summary & Significance • Similar results are not seen in their respective RNAi lines, although there a few discrepancies because the RNAi-lines may contain residual forms of the Msr. A or Msr. B gene. • As the flies approached senescence (60 -65 days), the decrease in average recovery time among the Msr. A and Msr. B deletion lines, indicate that there may be a novel compensatory mechanism causing this.

ACKNOWLEDGEMENTS • • • Dr. David Binninger Dr. Evelyn Frazier Dr. John Nambu Ramon Garcia and Chelsea Bennice Dr. Sarah Milton Lindsay Bruce Lab mates Honors Program and Peers National Institute of Health Grant FAU Undergraduate Research Grant

Questions? http: //www. cartoonstock. com/directory/f/fruit_fly. asp