urca poster turner

Introduction

Abstract Results

Methods

Discussion

Literature Cited

Acknowledgements

The$rela(onship$between$Drosophila$and$Saccharomyces$has$been$an$area$of$evolu(onary$study$for$decades.$$While$the$twos$interac(ons$are$well$documented$and$discussed,$the$en(rety$of$their$symbio(c$rela(onship$is$yet$to$be$fully$explored$and$established.$$Previous$studies$have$found$Drosophila*Melanogaster$to$be$able$to$dis(nguish$between$dierent$concentra(ons$of$sugar$sources$and$show$a$preference$to$sugar$types.$Drosophila$has$also$been$shown$to$be$able$to$recognize$areas$of$faCy$acids,$and$other$benecial$food$proteins.$$To$successfully$survive$passage$through$the$ies$diges(ve$tract,$yeast$species$must$have$previously$undergone$sporula(on.$Considering$that$vegeta(ve$cell$survival$through$the$y$gut$is$an$anomaly,$it$gives$the$yeast$strains$a$dis(nct$evolu(onary$advantage$to$aCract$ies$to$their$sporulated$forms.$

The$experiment$conducted$aimed$to$further$prove$Drosophilaes$ability$to$recognize$varying$levels$of$sugar$concentra(on$and,$primarily,$to$establish$a$preference$for$sporulated$or$vegeta(ve$Saccharomyces$Cerevisiae.$$Instruments$referred$to$as$FlyCafes$were$u(lized$to$quan(ta(vely$compare$feeding$consump(ons$of$varying$media.$$Dierences$in$consump(on$were$considered$a$direct$correla(on$to$preference.$$While$Drosophilae$Melanogaster$demonstrated$a$preference$for$higher$concentrated$sugars,$no$preference$to$either$state$of$Saccharomyces$Cerevisiae$was$observed.$

$!

D.$melanogaster$Prepara(on!Female!drosophilae!melanogaster!are!

raised!in!vials!lled!with!sugar!rich!solid!media.!!Females!were!knocked!out!using!FlyNapTM!and!isolated!using!microscopy!into!FlyCafe!Vials.!Eight!ies!were!isolated!per!vial.!!Flies!were!starved!for!6!hours!!

!$$

Media$Prepara(on!Spent!YPD!was!created!by!allowing!

uninhibited!yeast!cell!growth!in!pure!YPD!for!one!week.!!Yeast!cells!were!then!removed!via!sterile!ltraGon!and!the!remaining!YPD!was!autoclaved.!!SporulaGon!of!M4330!was!induced!with!potassium!acetate.!!VegetaGve!and!sporulated!versions!of!M4330!were!equalized!via!spectroscopy!once!resuspended!in!spent!YPD$

Feeding$and$Analysis!Two!categories!of!media!were!introduced!

via!capillary!tubes.!!ConsumpGon!of!media!was!allowed!for!24!hours.!!Immediately!proceeding!consumpGon,!capillary!tubes!were!removed,!and!consumpGon!rates!were!measured!in!millimeters!consumed.!

!!$$$

Our greatest appreciations go to Dr. Stephen Proulx and Kelly Thomasson, who mentored us through the entire course of the project. We would like to thank. We are also extremely grateful for the contribution of the UC Santa Barbara Undergraduate Research and Creative Activities (URCA) unit, as well as the Faculty Research Assistance Program (FRAP), as this project would have been impossible without their generous funding

The!relaGonship!between!Drosophila!and!Saccharomyces!has!been!an!area!of!evoluGonary!study!for!decades.!!While!the!twos!interacGons!are!well!documented!and!discussed,!the!enGrety!of!their!symbioGc!relaGonship!is!yet!to!be!fully!explored!and!established.!!While!the!benets!received!by!saccharomyces!are!apparent,!there!may!be!solid!evidence!that!supports!the!idea!of!a!nonScommensal!relaGonship!between!them!and!drosophila!species.!!This!project!aims!to!compile!substanGal!data!that!would!help!to!prove!that!Drosophila*Melanogaster!has!the!ability!to!dierenGate!sporulated!Saccharomyces*Cerevisiae!from!its!vegetaGve!cell!form.!

!Prior!research!has!clearly!indicated!that!yeast!species!are!able!to!uGlize!drosophila!movements!to!transport!to!new!nutrient!rich!areas2.!!This!uGlizaGon!nearly!guarantees!exposure!to!new!food!sources!with!liVle!energy!expenditure.!!While!some!transportaGon!is!acquired!through!the!limbs!of!drosophila,!it!has!been!well!documented!that!survival!through!the!gut!may!be!equally,!if!not!more,!eecGve.!While!the!assistances!gained!by!the!yeast!through!this!relaGonship!are!quite!obvious,!the!advantages!beWng!the!ies!are!less!apparent.!Studies!have!proven!that!adult!drosophilae!are!able!to!use!yeast!as!a!sole!source!of!food2,!however!this!is!rarely!applicable!in!the!natural!world.!!Far!more!oXen!ies!feed!upon!fruit!or!tree!sap,!ingesGng!yeast!cells!as!a!secondary!event.!!!

!To!successfully!survive!passage!through!the!ies!digesGve!tract,!yeast!species!must!have!previously!undergone!sporulaGon.3!Considering!that!vegetaGve!cell!survival!through!the!y!gut!is!an!anomaly,!it!give!the!yeast!strains!liVle!evoluGonary!advantage!to!aVract!ies!to!their!vegetaGve!forms.!!It!is!reasonable!to!hypothesize!that!it!would!be!evoluGonarily!

Howe!HF!(1986)!Seed!dispersal!by!ruitSeaGng!birds!and!mammals.!In:!Murray!DR,!ed.!Seed!Dispersal.!Orlando,!FL:!Academic!Press.!pp!123190.!Begon!M!(1986)!Yeasts!and!Drosophila.!In:!Ashburner!M,!Carson!H,!Thompson!JN,!eds.!The!GeneGcs!and!Biology!of!Drosophila.!London:!Academic!!Press.!pp!345384.!!Coluccio!AE,!Rodriguez!RK,!Kernan!MJ,!Neiman!AM!(2008)!The!Yeast!Spore!Wall!Enables!Spores!to!Survive!Passage!through!the!DigesGve!Tract!of!Drosophila.!PLoS!ONE!3(8):!e2873.!doi:10.1371/journal.pone.0002873!Masek,!P.!&!ScoV,!K.!Limited!taste!discriminaGon!in!Drosophila.!Proc.*Natl*Acad.*Sci.*USA107,!1483314838!(2010).!Sanchez,!Maria!Gabriela!De!Brito,!Esther!Lorenzo,!Songkun!Su,!Fanglin!Liu,!Yi!Zhan,!and!MarGn!Giurfa.!The!Tarsal!Taste!of!Honey!Bees:!Behavioral!and!Electrophysiological!Analyses.!Fron=ers*in*Behavioral*Neuroscience*(2014):!n.!pag.!Web.!Masek,!Pavel.!"Drosophila!FaVy!Acid!Taste!Signals!through!the!PLC!Pathway!in!SugarSSensing!Neurons."!PLOS*Gene=cs:.!10.1371/journal.pgen.1003710,!12!Sept.!2013.!Web.!04!Oct.!2014.!

Further understanding the inter-specie interactions amongst the most common model organisms is an important area of study within evolutionary biology. The eventual goal of identifying molecular reasons inducing evolved traits begins with discerning minute behavioral traits amongst organisms. Within this experiment, no statistically relevant selectivity was present within Drosophilae melanogasters traits in response to saccharomyces cerevisae sporulation. The lack of ability to discriminate between saccharomyces forms suggests Drosophilae is unable to identify extracellular proteins of microorganisms.

Consumption was measured in the unit of millimeters and was considered to be a direct representation of feeding preference. All data sets were statistically analyzed with a Students T-Test with an value of 0.5. In order to test the effectiveness of our device, Drosophilas ability to detect and prefer higher concentrations of sugar-rich media was tested. Pure yeast extract peptone dextrose (YPD) was compared to 100-fold diluted YPD. The raw data demonstrated that flies preferred higher concentrated YPD by an additional +7.957mm on average, with daily averages ranging from +14.75mm to 2.22mm. The student T-Test demonstrated high significance (p=.00046) These results were successfully replicated using spent-YPD as a media.

Vegetative M4330 was grown and resuspended Spent-YPD media. The flies had a very mild attraction to the addition of the yeast cells to spent-YPD. The overall average preference was found to be 5.21mm, with individual daily ratings ranging from +3.33mm to +8.286mm. This markedly reduced average preference demonstrates that Drosophila would prefer medias with higher sugar concentration than those with vegetation. However, with some preference it indicates there must be some ability to detect the presence of yeast in media.

When comparing feeding preference between the sporulated and vegetative state of M4330, drosophilae light preference for vegetative cells. The average preference towards vegatative was +1.13mm. This data, while significant, does not indicate a strong preference between sporulated and vegetative external protein structures.

Although this data suggests S. cerevisea does not actively attract D. melanogaster to its sporulated states, this research did not encompass the entirety of sporulation conditions. During sporulation a variety of unique bi-products are released that may be involved in attracting drosophilae. Through resuspension in sterile spent-YPD, these specific biproducts were removed.

Drosophila melanogasters feeding preferences to unique cell-surface molecules of Saccharomyces cerevisiae vegetative and sporulated states

Turner S. Baker*1, Cameron A. Gable, Victor H. Quach, Sarah Seagrave, Kelly M. Thomasson, and Stephen R. Proulx2

*1University of California, Santa Barbara Department of Molecular, Cellular, and Developmental Biology 2University of California, Santa Barbara Department of Ecology, Evolution, and Marine Biology

benecial!to!have!spores!appear!more!aVracGve!to!ies.!!By!enGcing!drosophilae!to!consume!areas!of!sporulated!cells,!the!yeast!has!a!greater!chance!of!survival.!!This!is!not!a!unique!idea!within!the!natural!world.!!Fruits!and!berries!were!similarly!designed!to!aVract!birds!to!increase!dispersal.1!!And!the!honey!bee,!an!insect!similar!to!drosophila*melanogaster,!is!able!to!disGnguish!between!wide!varieGes!of!substrates!in!order!to!beVer!acquire!pollen!and!sugar.5!

!Studies!have!found!Drosophila*Melanogaster!to!be!able!to!disGnguish!between!dierent!concentraGons!of!sugar!sources!and!show!a!preference!to!one!sugar!over!another.4!!Drosophila!has!also!been!shown!to!be!able!to!recognize!areas!of!faVy!acids,!and!other!benecial!food!proteins.6!!Figure$1:!FlyCafe!equipped!with!two!media!lled!capillary!tubes!and!two!breathing!tubes!

Figure 2: Example Consumption Measurement. Demonstrates difference in millimeters between two types of media exposed to starved female flies for 24hrs.

Figure 4: Pure YPD vs. 1:100 YPD. D. melanogaster demonstrated strong preference to higher concentrations of sugar-rich media..

Figure 2: Feeding Preferences and Significance Utilizing a student t test analysis, all results were found to be significant. YPD concentration was found to be the biggest factor in feeding behaviors, with addition of vegetative yeast boosting preference. Light preference was found between sporulated states, with drosophilae preferring sporulated cells.

29.8!

17.73!22.62!

0!

5!

10!

15!

20!

25!

30!

35!

YPD!vs.!Diluted!YPD! VegetaGve!M4330!vs.!Spent!YPD! VegetaGve!M4330!vs.!Sporulated!M4330!

Average$To

tal$C

onsump(

on$(m

m)$

18.87857143!

10.92142857!

0!

5!

10!

15!

20!

25!

Pure!YPD! 1:100!YPD!

Average$Co

nsum

p(on

$(mm)$

11.64705882!10.50980392!

0!

2!

4!

6!

8!

10!

12!

14!

VegetaGve! Sporulated!

Average$Co

nsum

p(on

$(mm)$

11.47619048!

6.261904762!

0!

2!

4!

6!

8!

10!

12!

14!

YPD!+!Veg! Pure!YPD!

Average$Co

nsum

p(on

$(mm)$

Compra(ve$Selec(vity$Dierence$in$Preference$ PQValue$

Degrees$of$Freedom$

YPD!vs.!Diluted!YPD! 7.957! 0.000456968! 138!

VegetaGve!M4330!vs.!Spent!YPD!5.2143! 1.69038ES06! 86!

VegetaGve!M4330!vs.!Sporulated!M4330! 1.1372! 0.032634678! 202!

Figure 5: YPD + Vegetative S. Cerevisea vs. Spent YPD. D. melanogaster had mild preference to spent YPD with vegetative S. cerevisea.

Figure 6: Vegetative M4330 vs. Sporulated M4330. D. melanogaster demonstrated extremely light preference to vegetative S. cerevisea.

Figure 3: Total Consumption. Shows relatively standard consumption over entirety of experiment. With 24 hour consumption times, 8 flies consistently ate ~20mm of media.

S5!

0!

5!

10!

15!

20!

25!

30!

1! 4! 7! 10! 13! 16! 19! 22! 25! 28! 31! 34! 37! 40! 43! 46! 49! 52! 55! 58! 61! 64! 67! 70! 73! 76! 79! 82! 85! 88! 91! 94! 97!100!

Consum

p(on

$(mm)$

Round$3$Trial$Number$