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Poster Full Abstracts - Neurophysiology and Behavior
Poster board number is above title. The first author is the presenter
294
607A
A new model of chronic social defeat in
Drosophila melanogaster
.
David Popovic
1
, Jill Penn
1
, Justin Dalton
2
, Michelle Arbeitman
2
, Edward Kravitz
1
. 1)
Neurobiology, Harvard Medical School, Boston, MA; 2) College of Medicine, Florida State University, Tallahassee, FL.
Behavioral changes following the loss of a fighting contest are exhibited in species throughout the animal kingdom. After experiencing a single loss
Drosophila
become less aggressive and lose subsequent fights. In mammals, chronic social defeat has been used as a model of depression- and anxiety-like
behaviors. Here we have developed a model of chronic social defeat in
Drosophila
. In order to increase the likelihood of a loss, Canton S males fought
against a larger fly from a hyper-aggressive strain, once a day for six consecutive days. Those males that lost all six fights were then paired in a test fight
against an age-, size- and genetically-matched socially naïve male on the seventh day. Twenty-four hours later the same males were tested in a sucrose
preference assay. Most flies displayed decreased aggression and subsequently lost their test fights, suggesting that they were susceptible to the experience of
chronic social defeat. These same flies also had a decreased sucrose preference and a decrease in their overall food intake. Moreover, we found that these
effects last at least one week after the six-day training period. We also found a resilient subpopulation of chronically defeated flies that behaved like control
flies in both test fights and sucrose preference assays, suggesting that they are resistant to chronic defeat. In order to determine the genetic mechanisms
underlying these two populations, we are now performing RNA-Sequencing analyses on susceptible and resilient chronically defeated flies (This work was
supported by grants from NIGMS to EAK, and from The German National Merit Foundation and The Max-Weber-Program to DP).
608B
Effects of RNAi-Mediated Suppression of Odorant binding protein 56h on Aggression and Mating Behaviors.
John R. Shorter
1
, Kavita Sharma
2
,
Anandasankar Ray
2
, Robert R. Anholt
3
, Trudy F. Mackay
1
. 1) Genetics, North Carolina State, Raleigh, NC; 2) Entomology, University of California,
Riverside, CA; 3) Biology, North Carolina State, Raleigh, NC.
Odorant binding proteins play an important role in chemosensation by transporting odorants to the receptor in the olfactory membrane. Previous research
has shown that disruption of odorant reception will alter chemosensory perception and change behavior. Here, we knock down Odorant binding protein 56h
(Obp56h) using RNA interference (RNAi). Gene expression of Obp56h is dramatically reduced in the RNAi line relative to the control. We performed a
comprehensive analysis of behaviors in the Obp56h RNAi and the control. We found that that RNAi-mediated suppression of Obp56h reduces male-male
aggression and increases the frequency of mating. The effects of Obp56h knock down on startle response, geotaxis, and phototaxis are very small compared
to the effects on aggression and mating behavior. We are currently performing RNA-Seq and single-unit recordings from the trichoid sensilla of RNAi and
control lines and will present these results. We hypothesize that Obp56h may be transporting an odorant for “maleness” or a signal for male quality.
609C
Drosophila olfactory-related preferences to diverse yeast volatiles profiles.
J R. Arguello
1
, Carolina Sellanes Parodi
2
, Yann-Ru Lou
3
, Andrew Clark
1
,
Robert Raguso
4
. 1) Mol Bio & Genetics, Cornell, Ithaca, NY; 2) Laboratorio de Ecología Química, Universidad de la República, Uruguay; 3) Dept. Of Plant
Biology,Cornell, Ithaca, NY; 4) Dept. of Neurobio and Behavior,Cornell, Ithaca, NY.
Our understanding of the molecular and cellular basis of Drosophila chemosensation has been progressing rapidly. These advances enable evolutionary
analyses aimed at understanding within and between species variation in these physiological pathways, and simultaneously provide motivation for furthering
our understanding of the ecological contexts in which the pathways operate. We have combined chemical ecological and behavioral approaches to
investigate olfactory-related fly preferences in response to a second model genetic system: yeast (S. cerevisiae), a known attractant and food source for
Drosophila. Our experiments were designed to 1) test for population variation in yeast volatile production, 2) test for population variation in D. melanogaster
preference towards differing yeast volatiles, and 3) test for preference differences between D. melanogaster and two closely related non-specialist species, D.
simulans and D. yakuba. Our chemical approach relied on 14 worldwide yeast accessions within a randomized block-common garden design, and headspace
sampling of volatiles using GC-MS. The results reveal extensive variation in volatile composition, particularly in 2-phenylethanol, ethyl esters of aliphatic
acids, and acetoin; these compounds have previously been shown to be Drosophila olfactory ligands either directly or indirectly. To test for variation in fly
preference to these varying volatile profiles, we have carried out single-fly choice experiments between the most variable yeast samples using a 4-armed
olfactometer, and have quantified behavior throughout the experiments by video analyses of their tracks. Our results indicate both within and between
species differences in responses to several of these profiles, and point to ecologically relevant compounds as modulators of these behavioral differences.
610A
The circadian neuropeptide PDF couples preferentially to a specific adenylate cyclase isoform.
Laura B. Duvall, Paul H. Taghert. Department of
Anatomy & Neurobiology, Washington University in St Louis, St Louis, MO.
The neuropeptide Pigment Dispersing Factor (PDF) coordinates
Drosophila
pacemaker cells and is essential for normal circadian function. However,
specific signaling components downstream of the PDF receptor (PDFR) remain unknown. Using live imaging of intact fly brains and transgenic RNAi
methods, we identify the particular adenylate cyclase (AC) isoform that is associated with PDF signaling in small LNv cells (also termed M cells). Genetic
disruptions of Gsα60A including both RNAi knockdown and overexpression alter responses to both PDF and the related peptide dh31. In a screen of all
Drosophila
AC isoforms, knockdown of a specific adenylate cyclase (AC3) disrupted PDF responses specifically in small LNv cells. Manipulations of AC3
disrupt PDF, but not dh31 responses. Loss of PDF responsiveness was rescued by restoring appropriate levels of AC3. Flies with AC3 alterations show
circadian dysfunction consistent with known roles of M cells. In addition, knockdown of the
Drosophila
AKAP-like scaffolding protein nervy reduces PDF
responses and disrupts circadian behavior. Together these results indicate that within small LNv cells, the PDF receptor couples preferentially to a single
AC, and that critical pathways of circadian synchronization are mediated by highly specific second messenger components.
611B
Extreme Light Sensitivity in
Drosophila
.
P. Fozdar, J. Coupar, S. Hughes, P. Vinayak, W. Brasher, J. Kilby, J. Hirsh. Dept. of Biology, University of
Virginia, Charlottesville, VA 22904.
We study the basis for the extreme light sensitivity of Drosophila melanogaster. Drosophila can entrain to LD cycles, and show positive behavioral
masking, at light intensities below the limit of human perception. We find that both visual input via the R1-6 rhabdomeres and input from cryptochrome are