AbstractBook

April 27, 2018 SW 309

Art by: Sophia Lavergne

Session1|LongTalksYoutakethehighroadandI’lltakethesilkroad:malewidowspidersfindfemalesfasterbyfollowingsilktrailsofrivalsCatherineScott,SeanMcCann,MaydianneCBAndradeSocialinformationcanallowindividualstobypassthecostsandrisksofexploration,butmayalsointensifycompetition.Hereweshowthatmate-searchingmalescanexploitinadvertentsocialinformationproducedbyrivalstofindfemalesfaster,increasingtheirmatingsuccessinspiteofheightenedcompetition.Inwesternblackwidows(Latrodectushesperus),first-malespermprecedenceleadstointensescramblecompetitionforaccesstosedentaryfemales.Unmatedfemalessignaltomalesviasilk-boundpheromones,butceasesignalingshortlyaftercopulation.Throughfield-andlab-basedstudieswedemonstratethatfemalesmatureasynchronouslyinnature,creatingbriefwindowsofdetectability.Largermalesaremoresuccessfulatlocalizingfemales,butsmallermalesachievehigheraveragesearchspeeds.Critically,allmalesimprovetheirmate-searchingsuccessbyfollowingsilkdraglines(byproductsoflocomotioninspiders)producedbyrivalstoarriveatreceptivefemales’websfaster.Silk-followingmalesenterwebsinwhichrivalsarealreadycourting,butpre-copulatorycourtshiplastsseveralhours,sothefirstmaletoarriveisnotnecessarilyfirsttomate.Moreover,weshowthatmate-searchingmalesvastlyoutnumbersignalingfemalesonanygivennight.Weconcludethatsocialinformationusebymalesincreasestheirfitnessbecausepatternsoffemalereceptivitynecessitatecompetition.NeuralandBehaviouralPatternsofWithin-TaskandBetween-TaskMentalFatigueZoëFrancis,AkinaUmemoto,&MichaelInzlichtMentalfatiguewithinonecontinuous,effortfultaskisreliablycharacterizedbyworseningperformanceandreducedneuralreactionstoerrorsasthetaskcontinues.Egodepletioneffects–wherefatigueoriginatesinonetaskandnegativelyaffectsperformanceonasubsequentsecondtask–occurslessreliably.Fatiguemaynotsimplycrossbetweentasks,especiallyiftask-switchingrestoresortemporarilyrecoversmotivationorattention.Thisstudyexaminedpatternsofperformanceandneuralengagement(measuredusingEEG),forbothwithin-taskfatigueandbetween-taskdepletion.Participants(N=72)completeda40-minuteStrooptaskimmediatelyfollowedbya10-minuteGo/No-Go.Bothcognitivetaskswerestronglyaffectedbywithin-taskfatigue,withperformanceandneuralengagementdecreasingacrossthecourseofeachtask.Between-taskfatigueeffects(depletion)werenotapparentatthebeginningofthesecondtask;neitherperformancenorneuralindicatorsofengagementsignificantlydifferedwhencomparingbaselineGo/No-Gotothepost-fatigueGo/No-Go.Instead,switchingtasksresultedinre-engagementofcognitivemonitoringprocesses,withincreasedneuralengagementfromtheendoftheStrooptothebeginningoftheGo/No-Go.Self-reportedmeasuresofengagementalsodecreasedwithineachtask,andpartiallyrecoveredwhenthetaskchanged.Theseresultssuggestthatpotentialbetween-taskdepletioneffectsmaybeweakenedbyinitialreengagementthatoccurswhenonedifficultcognitivetaskends,andanotherbegins.

Understandinginvasiveness:anintegratedassessmentoftraitsleadingtoinvasionsuccessinwidowspidersM.A.Mowery,A.Dorison,A.C.Mason,M.C.B.AndradeUnderstandinginvasivenessisanongoingchallenge.Therearedebatesaboutwhichtypesofbehaviouralandphenotypictraitsfacilitateestablishmentinnovelenvironments.Wepredictedthatspidersfrominvasive(Japanese)populationsofredbackspidersLatrodectushasseltiwouldperformbetterthannative(Australian)spidersundertemperaturestypicaloftheinvasiverange,evenafter‘commongarden’rearing.Herewereportdifferentialeffectsoftemperatureonbehavioural,morphological,andlifehistorytraitsandtrade-offsthatarelikelytounderlieinvasivesuccess.Spidersfrominvasivepopulationsweremorecannibalistictowardssiblingsandmoretolerantoftemperaturechallenges.WhenheldunderAustralia-typicalandJapan-typicaltemperatures,eggsacsfromtheinvasivepopulationexperiencedlessofadelayindevelopmentandhadhigherhatchingsuccessincool,Japan-typicaltemperaturesthandidAustraliansacs.Asjuveniles,invasivesshowedmorebehaviouralplasticityinresponsetotemperaturedifferences.Asadults,invasivefemaleshadhigherfecundity.Nevertheless,spidersfromtheinvasivepopulationwerelargerandtooklongertodevelop.Invasivepopulationsmaybeabletothriveinnovelenvironmentalconditionsbecauseofincreasedbehaviouralplasticity,toleranceoftemperaturefluctuations,andhigherfecundity.Wespeculatethatspecies-leveldifferencesinthesetraitsmayexplainvariablepatternsofinvasionsuccessacrossthewidowspidergenus.ParasitetransmissionbetweenwildanddomesticcarnivoresaroundprotectedareasJuanSebastiánVargasSoto,PéterK.MolnárParasitetransmissionbetweenwildanddomesticspecies(livestockandpets)createsamajorriskofemergingdiseasesandepidemics.Toproperlyaddressthesethreatsandpreventdiseaseoutbreaks,weneedtounderstandhowdifferenthostspeciescontributetothepersistenceoftheparasite.IanalyzedthisissuewithAncylostomacaninum,anintestinalparasitethataffectsdomesticdogsandwildfelinesinSouthernCostaRica,todetermineifdogsorocelotsareactingasreservoirhosts.Icollectedandanalyzedscatsamplesfromthesetwospeciestoestimatetheparasiteprevalence.Iusedcamera-trapstoestimatehostabundanceandspatio-temporaloverlap.Withthesedata,Iusedanepidemiologicalmodelformultiplehostswithenvironmentallytransmittedparasitestoquantifytherelativecontributionsofeachhostspecies.Myresultsshowthatdogswouldbeactingasreservoirhosts,andtheparasitespillsovertowildocelots.Sensitivityanalysesshowthatonlyforafewcombinationsofparametervaluestheparasitecouldbesustainedbybothhostsindependently.Thisinformationcanbeusedtodesignmanagementstrategiestopreventnegativeeffectsoftheseandothersimilarparasitesonwildspecies.Myresultsshouldbeupdatedtoincludeotherpotentialhosts,andwithmoreaccurateestimatesofprevalenceandabundance.

Session2|LongTalksCanRFMOsManageFisheriesDuringClimateChange?BrianPenntzThisstudyevaluatestheframeworksof12RegionalFisheriesManagementOrganizations(RFMOs)against28criteriatoassesswhethertheseorganizationscaneffectivelyrespondtoresourcefluctuationsbroughtaboutbyclimatechange.RFMOsareassessedonbreadthofmanagementframeworksandinclusionofbestavailablescienceinpolicyframeworks.Theassessmentmethodbuildsuponapreviouslypublishedframework,butisexpandedtocaptureorganizationalattributesassociatedwithaneffectiveresponsetoclimatechange.TheresultsoftheRFMOassessmentsuggestthatgenerally,RFMOpolicyframeworksarecomprehensive,andseemtopossessmostelementsrequiredtoachieveresourcemanagementgoalsunderclimatechange.Thestudyhypothesizesthatthelegal(i.e.issuesofcomplianceandenforcement,sovereignty,decision-makingrules)andpoliticalfactors(i.e.factorsintrinsictocommon-poolresources)characterisingthemanagementoftransboundaryandhighseasfisheries,ratherthanframeworkcomprehensiveness,arepredominatelyresponsibleforresourceoutcomesinRFMOs.Tofurtherpromoteeffectiveresourcemanagementanddesiredoutcomesduringclimatechange,thestudymakesfourrecommendations:(1)prioritizeperformanceevaluationfromaclimatechangeperspective,(2)continueenhancementofenforcementandmonitoringstrategies,(3)increasethedesignationofmarineprotectedareas(MPAs)and(4)includepoliticalanalysisofdecision-makingprocessesinRFMOs.ThecomplexgovernanceandpoliticalfactorsaffectinghighseasandtransboundaryfisheriesmanagementunderclimatechangeunderscorestheimportanceoftheupcomingBiodiversityBeyondNationalJurisdictions(BBNJ)treatyforitspotentialtosupporttheconservationofhighseasmarinelivingresourcesinparallelwithRFMOs.InvestigationofDaphniamagnasub-lethalexposuretoorganophosphateestersinthepresenceofdissolvedorganicmatterusing1HNMR-basedmetabolomicsVeraKovacevic,AndréJ.SimpsonandMyrnaJ.Simpson

Organophosphate esters (OPEs) are frequently detected in aquatic environments. Hydrophobic OPEs with highoctanol-waterpartitioncoefficients(LogKOW)willlikelysorbtodissolvedorganicmatter(DOM)andconsequentlyalterOPEbioavailabilityandsub-lethaltoxicity.1Hnuclearmagneticresonance(NMR)-basedmetabolomicswasusedtoevaluatehowDOM(5mgorganiccarbon/L)altersthemetabolicresponseofDaphniamagnaexposedtosub-lethalconcentrationsofthree individualOPEswithvaryinghydrophobicity.D.magnaexposedtothehydrophiliccontaminant(LogKOW=1.43)tris(2-chloroethyl)phosphate(TCEP)didnothavesubstantialmetabolicchangesandDOMdidnotalterthemetabolicresponse.Thereweresignificantincreasesinaminoacidsandadecreaseinglucosefromexposuretothehydrophobiccontaminant(LogKOW=3.65)tris(2-butoxyethyl)phosphate(TBOEP)whichDOMdid not mitigate, likely due to the high sub-lethal toxicity of TBOEP. Exposure to DOM and the hydrophobiccontaminant(LogKOW=4.76)triphenylphosphate(TPhP)resultedinauniquemetabolicresponsewhichwasunlikeTPhPonlyexposure,perhapsbecauseDOMmaybeanadditionalstressorwithTPhPexposure.Therefore,LogKOWvaluesmaynotalwayspredicthowsub-lethalcontaminanttoxicitywillchangewithDOMandthereshouldbemoreconsiderationtoincorporateDOMinsub-lethalecotoxicologytesting.

Anefficientmethodforchoosingthebestsub-ensembleofclimatemodelsfor∆TProjections

ConorI.Anderson·KenButler·WilliamA.Gough

ClimatescientistsproduceprojectionsoffutureclimateusingGlobalClimateModels(GCMs),however,foraregionalclimate study, it is sometimes inconvenient or otherwise impractical to analyze each of the available modelsindividually.Often, scientistswill instead perform an `ensemble` study, by averaging the output of all availablemodels.Recentstudieshaveshown,however,thatrepresentativesub-ensemblesmayoutperformindividualmodelsandfullensemblesalike.Weproposeanefficientmethodfortheselectionofrepresentativesub-ensemblemembersforΔTprojectionsbasedonthesub-ensemble'sability to reproduceanobservedclimatebaseline.WeusedourmethodtovalidateGCMreproductionoflong-termbaselinetemperatureaveragesatTorontoandMontreal,andfoundthatsub-ensemblesconsistentlyoutperformedindividualmodelsandtotalmodelensembleswhentestedforindividual variables and stations. Furthermore, sub-ensemblesweremore effective at reproducing the baselineaverageacrosscombinationsofvariablesandstations.Ourmethod,derivedanddevelopedintheRprogramminglanguage for statistical computing, provides a fast, computationally efficient solution to the selection ofmodelmembersofselective,representativesub-ensembles.

Session2|ShortTalks

DetectingevidenceofpositiveselectioninkeyosmoregulatorygenesinfreshwaterandmarineBeloniformes

KatherineBalasingham Physiochemicalbarriers,suchasdifferencesinsalinity,isachallengeforaquaticorganismstoovercome.Evolutionaryshiftsbetweenmarineandfreshwaterhabitatsrequiresevolutionarychangesinosmoregulation.Marinefishregulatetoincreasewateruptakeandremoveintracellularionstoavoiddehydration,whereasfreshwaterfishneedtoexcretewaterandretainions.Genesinvolvedinregulatingintracellularionconcentrationandmovementofwaterworktomaintaininternalionandwaterbalance.Evolutionarychangesinthesegenesarelikelyassociatedwithmarinetofreshwaterhabitattransitions,allowingfreshwateradaptionandspeciation.SelectivepressureswillbeanalyzedonseveralosmoregulatorygenesintheBeloniformes(e.g.needlefishes,medakas,flyingfishes,andhalfbeaks),anorderthatincludesmultiplemarineandfreshwaterlineages.Phylogeneticapproachessuchastestingnucleotidesubstitutionrateswillbeimplementedtodetectevidenceofpositiveselectionincandidategenesassociatedwithosmoregulation.

ANewFamilyofSmallManganese(III)PorphyrinBasedMRIContrastAgentsandtheAnalysesoftheBindingtoHumanSerumAlbuminPiryankaSasidharan,HanlinLiu,Dr.Xiao-anZhang

Introduction.Magnetic resonance imaging (MRI) relies on the 1H-NMR signal ofwater existing in vivo. Variableproton densities and relaxation properties produce variable signal intensity. In cases of no significant signaldifference,acontrastagent(CA)isoftenemployedtoallowtissuecontrastenhancement.TheeffectivenessofaCAisreferredtoasrelaxivity(r1)andisgiveninmM-1s-1.Currently,gadoliniumbasedCAs(GBCA)dominatesclinicusebutunfortunatelyGBCAsareassociatedwithGd-toxicity,suchasnephrogenicsystemicfibrosis(NSF)inpatientswithrenaldysfunction.Additionally,relaxivityisseentodecreaseatmagneticfieldsof1-3T,limitingitsfutureapplicationwherehighfieldclinicalscannerswilldominate.1Toovercometheselimitations,wehavedevelopedanumberofmanganese(III) porphyrin (MnP) alternatives to conventional GBCAs. MnPs have been found to display highrelaxivity,containsabiocompatiblemanganeseatitscoreandtheporphyrinbackboneallowsforversatilestructuralmodifications.2Herewereportanovelfamilyofsmall,asymmetricMnPsformagneticresonanceangiography(MRA)withhighrelaxivityanddisplayaffinitytohumanserumalbumin(HSA),aprominentproteinwithinthebloodplasma.Methods. MnTPPShasbeenpreviouslyshowntodisplay long invivoretention.This is likelyduetothediffusedhydrophobicityalongtheperimeterofthemolecule.3Additionally,MnTCPhasbeenpreviouslysynthesizedbyourgroupasanalternate toMnTPPSwhereby the fourPhSO3

-armswere replacedwithcarboxylatesasameansofincreasingwatersolubilityandpolarity.AseriesofMnPshavebeendesignedhereinbaseduponthesetwomolecules(Fig1)andcontainoneuniquesubstitutionforbindingtoHSA.

Fig1.Chemicalstructureofmoleculesleft:MnTPPS,middle:MnTCP,right:novelMnPsdesignedherein

The novelMnPs have been synthesized and a series of spectroscopy techniques have been used to confirm itsidentityandpurity.Nuclearmagneticresonancedispersion(NMRD)profileswereacquiredwithaSMARTracer™FastFieldCyclingNMRRelaxometerincombinationwithavariablehighfieldrelaxometer(10–120MHz)HSAbindingwasfollowedbyrelaxivitychange.Results.AllnovelMnPsweresynthesized,purifiedandcharacterizedbyuseofNMR,UV-VIS,ESI-MSandHPLC.NMRDprofileofMnTriCPPwasobtained(Fig2).MnTriCPPwasfoundtodisplayadrasticrelaxivityincreaseuponHSAbinding.Moreover,themaximumr1wasfoundtobe21.0mM-1s-1at31.6MHzandathighclinicalfieldsanr1of14.8mM-1s-1wasobtained.Conclusion.ThenewfamilyofMnTriCPPanalogsexhibitsignificantimprovementtopreviouslysynthesizedMnPsandGBCAs,withhighsensitivityuponHSAbinding,anddisplayspotentialforfutureinvivoMRAapplications.References.1JMedChem.2014;57(2):516-520.2JBiolInorgChem.2014;19(2):229-235.3MagnResonMed.1987;33:24-33.

N N

N NMn

SO3

O3S SO3

SO3

N N

N N

O+Na-O

+Na-O O

O

O-Na+MnR

R = H: MnTriCPP

R =

R =

: MnTriCDP

: MnTriCIP

N N

N N

O+Na-O

+Na-O O

O

O-Na+Mn

O+Na-O

Fig 2. NMRD profile

KissingCousins:PopulationDensityPredictsEffectsofKinshiponMatingOutcomesinWidowSpiderPopulationsNishantSinghPopulationdensityaffectsselectionontraitsthatshapereproductivefitness,thuslinkingecologyandevolution.Westudiedhowdensityaffectsmatingbehaviour,responsetokin,andinbreedinginblackwidows(Latrodectushesperus).Weusedtwofocalpopulations—BritishColumbia(BC)andCalifornia(CA)—thatdifferinaveragedensityandspatialvariationindensityacrosstheiractiveseason.Highdensitiesintensifymale-malecompetitiongivenfirst-malespermprecedenceinLatrodectus,andincreasethelikelihoodofinbreeding.Wepredictedinbreedingtoleranceandadaptationstointensifymatingcompetitioninthehighdensity,facultativelygroup-livingBCpopulation,andconversely,discriminationofkinandinbreedingdepressioninthevariable,yetlower,density,solitaryCApopulation.Wepairedfemaleswithkinornon-kinmaleswithineachpopulation.HighdensitylineagesfromCAshowedslowmatingprogressinkinpairs,comparedtolowdensitylineages,orwhenpairswerenon-kin.Moreover,thesekin-matingswerecostly,withfewereggshatchingandloweroffspringsurvivorship.Comparingbetweenpopulations,BCpairsprogressthroughmatingfaster,andthisrelationshipisintensifiedinkinpairs,oppositetokininCA.Thisresultsuggestslocaladaptationtodistinctecologiesandcompetitiveenvironmentslinkedtosustaineddifferencesindensity.Influencesonquantityandqualityofdissolvedorganicmatterbyland-usedifferencesHuanTongDissolvedorganicmatter(DOM)isaheterogenousandcomplexmixtureofmoleculesprimarilyderivedfromplantsandmicrobes.Itisfoundubiquitouslyinterrestrial,aquaticandatmosphericsystems.Asamajorpoolofactivelycyclingorganiccarboninsoils,terrestrial-derivedDOMcanalsobeamajorcarbonfluxtootherenvironments.DOMchemistrycanalsovary,dependingonthetypeofterrestrialecosystem.Forexample,DOMderivedfromforestsischemicallydistinctfromDOMderivedfromagriculturallands.Theamountofcarbonexportedisalsodependentonecosystemtypeandenvironmentalproperties.Inaddition,land-usechangeslikelyaltertheamountandcompositionofDOMexportedtoaquaticsystems,butrarelyhasthisaspectstudiedwithotherenvironmentalfactors.Toaddressthis,themolecularcompositionandquantityofextractableDOMfrombothnativeandcultivatedNorthandSouthAmericansoilsalongameanannualtemperaturegradientwereanalyzed.Water-extractableorganicmatter(WEOM)sampleswereisolatedandanalyzedwithsolution-statenuclearmagneticresonance(NMR)spectroscopyandtotalorganiccarbonanalysisforcompositionandconcentrationdetermination,respectively.Withland-usechanges,thevariationsofconcentrationofWEOMshowedadecrease(r2=0.6033)withincreasingmeanannualprecipitate.NMRanalysisshowedthatthedominantcomponentofcroplandWEOMwasfromcarbohydratesandpeptides.Thearomaticityofnativeforest-derivedWEOMdecreasedfasterperyearafterland-usechangestopastureland.Basedonthestudy,land-use,includingvegetation,andotherenvironmentalfactorschangedthequantityandqualityofDOM.Furtherstudywillbeperformedwithlong-termcroprotationtobetterunderstandtherelationbetweenvegetationandqualityandquantityofDOM.

Understandingtheroleofsedimentdiagenesisandhowit’scapturedbymechanisticmodelsappliedtoLakeErieMeghanBrady,YukoShimoda,GeorgeArhonditsisTheuseofmechanisticecologicalmodelshasallowedfortheidentificationandunderstandingofimportantin-lakeprocessthatareknownaffectthetrophicstateandwaterqualityofLakeErie.Specifically,theyarecommonlyappliedtoLakeErieasanenvironmentalmanagementtooltopredicteutrophication,harmfulalgalblooms(HAB),andhypoxicevents.Thesemodelsattempttocapturecriticalin-lakeprocesses,suchassedimentdiagenesis,whichmaycauseinternalloadingandinfluenceeutrophication,HABs,andhypoxia.OurresearchfocusesonidentifyingtheroleofsedimentsdiagenesisandhowtheseprocessesaredescribedbymechanisticmodelsappliedtoLakeErie.Wewillexaminehowwellthesemodelshaveproperlyreproducedtheinfluenceofsedimentprocessesontheinternalloadingofthesystemandalsoevaluatethemathematicalequationsused,methodologicalpracticesfollowed,andlessonslearnedfromthesemechanisticmodels.

Session3|LongTalksHSP90CfunctionsinthethylakoidtargetingofPsbO1throughinteractionwiththethylakoidtargetingpeptideTimJiangTheplastidheatshockprotein90(HSP90C)hasbeenshowntoserveasanessentialcomponentoftheplastidproteinqualitycontrolsystem.Previously,wefoundthatHSP90CinteractswiththePSIIsubunit,PsbO1,enroutetothethylakoid.Whilethesteady-statelevelofiPsbO1(stromalform)andmPsbO1(lumenform)wasmodifiedinthepresenceofdifferentialHSP90Cactivity,theexactcauseofthisalterationwasunknown.Usingseedlingswhichonlyexpressedthechloroplasttargetingpeptide(cTP)andthylakoidtargetingpeptide(tTP)ofPsbO1fusedtoGFP(PsbO11-85GFP),westudiedthedynamictraffickingofthetTPfusionproteinbyusingisolatedchloroplasts.OurthylakoidtransportchaseassaysshowedthattheHSP90ATPaseinhibitorgeldanamycincouldcauseareversibleinhibitionoftTPtransportacrossthethylakoidmembrane.Analysesoffractionatedstromaandthylakoidsamplespost-chasesuggestedthatHSP90Cactivityisnecessaryforstroma-to-thylakoidmovementofSECtransloconsubstrates.Basedonourobservations,weproposethatHSP90CregulatelumentransportofPsbO1bytheselectivestromaltargetingoftheTPPtowardsthethylakoidmembrane.

TheSnRK1interactionnetworkplaysaroleinsaltstressresponseinArabidopsisthalianaCarinaCarianopolYearly,abioticstressisresponsiblefor70%ofcropyieldloss.50%ofagriculturallandisaffectedbyhighsoilsalinity,andwiththeexpectedincreaseinfooddemandoverthenextfewdecades,itisimportanttostudymechanismsofplantabioticstressresponsetoengineerbetterstress-adaptedcrops.Plantshavedevelopedintricatemechanismstoenablesurvivalunderabioticstress.Oncethestressissevereenough,theplantreachesastatusofenergydeprivation.TheplantSnRK1(Sucrosenon-fermentingRelatedKinase1),yeastSnf1andmammalianAMPKareconservedenergysensorsactivatedundermetabolicstresstoachieveenergyhomeostasis.TheSnRK1heterotrimerickinasecomplexcomprises2catalytic(SnRK1a),3regulatorybetaand2gammasubunits,oneofwhichisplant-specific(by).SnRK1hasbeenproposedtolinkstress,sugaranddevelopmentalsignalstoregulateplantmetabolismandenergybalanceandthereforesurvivaloftheplantunderstress.Importantduringabioticstressresponse,isthehormoneabscisicacid(ABA).RecentworkindicatesthattheSnRK1andABAsignalingpathwayssharecommontranscriptionaltargetsduringstressresponse,althoughthemechanismofthiscrosstalkisunclear.TheaimofthisprojectistoinvestigatehowSnRK1andABAinteracttoregulateabioticstressresponsesinArabidopsisthaliana.Ahigh-throughputyeasttwo-hybrid(Y2H)screenusingallSnRK1subunitsagainstalibraryof258ABA-regulatedgeneswasperformed,resultingin47putativeSnRK1substratesidentifiedintheABA-SnRK1interactionnetwork.Bioinformaticsanalysissuggeststhatacoresubsetof10novelSnRK1-PP2C-ABApartnersmayorchestratetheplantresponsetosaltandosmoticstress.Severaloftheseinteractionshavebeenconfirmedinplanta.Theirpossibleroleinmediatingtheresponsetosaltandosmoticstresswillbediscussed.PredictingthelikelihoodofaregimeshiftinCootesParadisewithstatistical&mathematicalmodelsCindyYang,Dong-KyunKim,GeorgeArhonditsisDespiteextensiverestorationefforts,CootesParadisecontinuestobedegradedandseeminglyunabletorevertbacktoitsformerclearstate.Previousworkhasfailedtoaddressthespatialheterogeneityinthesystemwhencharacterizingitsecologicalfunctioning.Ourmodellingstudywillevaluatethespatially-explicitecosystemresponseinCootesParadiseto:(1)nutrientreductionsinwastewatertreatmentplantdischargeand(2)thepresenceofsubmergentvegetationcommunities.ThepresentmodellingexercisecombinesourbestecologicalunderstandingofCootesParadiseandobserveddatatodrawpredictionsabouttheecosystemresponsetonutrientloadingreductionsandre-establishmentofsubmergentvegetation.Weevaluatedthecombinedeffectsofsubmergentvegetationandnutrientloadingreductions,asprojectedbyacalibratedeutrophicationmodel.WethendevelopedaBayesianstatisticalmodeltoanalyzethespatialdistributionofreducednutrientloadingimpactanddelineateareasinCootesParadisewherethegreaterwaterqualityimprovementswilllikelyoccur.WeconcludebydiscussingthevarioussourcesofuncertaintyandadditionalremedialactionsrequiredinCootesParadisemarshtorealizeashiftfromthecurrentturbid-phytoplanktondominatedstatetoitsformerclear-macrophytedominatedstate.

Session3|ShortTalksTemperatureandtactilestimulationalterstress-relatedgeneexpressionintheneonatalratbrainSamanthaC.Lauby&Dr.PatrickO.McGowan

Earlylifeexperiencescanaffectstressresponseinlaterlife.Inratpups,maternallicking/groominginthefirstweekoflifecanregulateadultstressreactivity.However,wedonotknowwhetherthetemperaturedroppupsexperienceduringthemother’sabsencefacilitatetheeffectsoflicking/groomingwhenthemotherreturns.Tostudythispotentialinteraction,webrieflyseparatedpupsinthefirstweekoflifeatroomtemperature(19-21°C)ornesttemperature(33-35°C)andprovidedhalftheanimalsinalitterwithsupplementaltactilestimulation(aproxyforlicking/grooming).Resultsindicatethattemperatureconditionsaffectedcorticotrophin-releasingfactorandoxytocingeneexpressionintheweek-oldratparaventricularnucleusofthehypothalamus.Inaddition,tactilestimulationdecreasedparaventricularcorticotrophin-releasingfactor,oxytocin,andargininevasopressingeneexpression.Thesefindingssuggestthatbothtemperatureandtactilestimulationaffectgeneexpressionrelatedtothestressresponseearlyinlife.Wearecurrentlyinvestigatingthyroidhormone,implicatedinbothtemperatureandtactilestimulation,asamechanismforthesedifferences.Changesinsoilorganicmattercompositionwithlong-termforestsoilwarmingandnitrogenadditionLorivandenEndenandMyrnaJ.SimpsonSoilorganicmatter(SOM)isthelargestpoolofactivelycyclingorganicmatterandtwo-thirdsofthisSOMisstoredinforestsoils.Asglobaltemperaturesandatmosphericconcentrationsofgreenhousegasescontinuetorise,itisimportanttomaximizethecarbon(C)storagecapacityofSOM.Atthesametime,itisunclearhowforestswillrespondtofutureenvironmentalconditions,includingwarmertemperaturesandgreaterratesofnitrogen(N)deposition.Tobetterunderstandtherelationshipsbetweenlong-termwarming,NadditionandSOMcomposition,astudysitewasestablishedatHarvardForest,MAin2007.Atthissitefourtreatmentswereappliedcontinuously:Control,Warming(soiltemperaturewasincreasedby5°Cusingheatingcables),N-Addition(NappliedannuallyasNH4NO3)andWarming+N(acombinationoftheWarmingandN-Additiontreatments).Aftertenyears,theOandAhorizonsweresampledandanalysedatthemolecularlevelusingbiomarkermethodsandnuclearmagneticresonance(NMR)spectroscopytomeasureSOMcompositionanddegradationstate.ResultsofNMRspectroscopyshowthatinalltreatments,theSOMintheAhorizonismoredegradedthanintheOhorizon,whichisreceivingcontinuousfreshinputsfromabove-groundlitter.TheWarmingtreatmentsappeartohaveaccelerateddegradation,particularlyintheAhorizon.Incontrast,theN-Additionmayhavesuppresseddegradation.TheresponseoftheWarming+NtreatmentismostsimilartotheWarmingtreatment,whichsuggeststhataftertenyears,soilwarmingcontrolsdegradationmorestronglythanN-Addition.Molecular-leveldatawillprovidedetailedinformationaboutSOMcompositionandbiogeochemistry,whichwillimproveunderstandingoftherelationshipbetweenfutureclimatechangeandCstorageandcyclingintemperateforests.

TheInfluenceofAtmosphericHalogenatedOzoneDepletingSubstancesonArcticAmplification

JohnVirgin,KarenSmithThegloballywarmingclimate,asdepictedthroughallpotentialRadiativeConcentrationPathway(RCP)scenariosfromtheIntergovernmentalPanelonClimateChange(IPCC),standstohaveanexacerbatedeffectatpolarlatitudes.Thisprocess,knownasArcticAmplification,hasforecastedwarmeraverageArctictemperaturesthantheglobalaveragethroughvariousclimatologicalmechanisms.Onesuchpotentialmechanismistheinfluenceofhalogenatedozonedepletingsubstances(ODS)onthenaturalcycleofozonedestructionandproduction,aswelltheirdirectimpactonclimaticwarmingaspotentgreenhousegases.ElucidationofthepreciserelationshipbetweenODS'sandArcticAmplificationhasnotyetbeenascertainedinpastresearcheffortsduetothecomplexnatureofprocessesshapingtheArcticClimate.Here,weuseoutputfromthreecompletedsimulationsofafullycoupledGeneralCirculationModel(GCM)withatmosphericchemistry,knownastheWholeAtmosphereCommunityClimateModel(WACCM),toinvestigatetherelationshipbetweenODS'sandArctictemperaturesthroughoutthestratosphereandtroposphere.Thecontrolsimulationincludesthreerunsfrom2005to2065,whichimposegreenhousegasemissionsequivalenttotheIPCCRCP4.5scenario.The"WorldAvoided"simulationincludesthreerunsfromthesametimeframeandwiththesameinputsasthecontrolsimulation,saveforaprescribed3.5%emissionincreaseofODS'sperannum.Lastly,the"fixODS"simulationincludesthreerunsfromthesametimeframe,andisidenticaltothecontrolsimulation,exceptforafixedlevelofODS'sfortheentiretimeframeequivalenttohistoricallevelsfromtheyear2000.Preliminaryspatialcomparisonsofdecadalsurfacetemperaturechangesacrossallthreesimulations,aswellasverticaltemperatureprofilesforeachseason,haveshownelevatedlevelsofwarmingandalteredlapserates.KeyfindingsforsuchresearchindicatetheimportanceofthestilllingeringtraceamountsofhalogenatedozonedepletingsubstancesinEarth'satmosphere,aswellasthepastandpotentialfutureinfluenceofozonedepletiononArcticAmplification.EffectsofearlylifestressonoffspringHPAaxisdevelopmentandbehaviour.MoulyRahmanNutrientsplayakeyroleinregulatingprenatalandearlypostnatalneurodevelopment.Atthesestages,offspringexhibitthehighestdegreeofneuroplasticity,andthus,arevulnerabletomaternalnutrientimbalance.Bycreatinganinflammatoryenvironmentfordevelopingoffspring,maternalhigh-fatdiet(mHFD)actsasaprenatalstressor.Epigeneticmodifications,chemicaltagswhichactivateorsilencegeneexpression,aresensitivetoprenatalstressors.Influencedbyepigeneticchanges,thehypothalamic-pituitary-adrenal(HPA)axisisaneuralsystemthatrespondstostressthroughsignalingofglucocorticoids(GCs)ontoGCreceptors(GRs).InflammationcausedbymHFDimbalancesGC-GRdynamics,sincetheHPAaxisandimmunesystemarelinked.Modulatingcognitionandstress,limbicbrainregionsexpressGRs,thus,disruptedGC-GRdynamicsduetoimmuneinterferencefrommHFDcanleadtolong-termeffectsonoffspringbehaviour.AsalteredimmunityhasbeenshowninoffspringexposedtomHFD,itremainstobestudiedwhetherapost-natalimmunestressorinteractswithhigh-fatdietinducedneuralremodeling.Toinvestigatethisinteraction,theproposedstudywilldeliveranimmunestressortooffspringexposedtomHFD.StressbehaviourandtheepigeneticprofileofHPAaxismarkersinlimbicbrainregionswillbeassessed.

DefiningtheinfluenceofchannelcomplexityonthedistributionoftracemetalsinsuspendedsedimentsinsaltimpactedurbanstreamsAiméKayembe,CarlP.J.Mitchell,Widespreadurbanizationhasledtoincreasedtracemetalandsaltlevelsinurbanstreams.Inadditiontoitsimpactonwaterquality,changestochannelgeomorphologyarepervasiveinurbanizinglandscapesresultingfromdramaticalterationsinthestreamhydrograph.Tracemetalsdistributioninsaltimpactedsystemshasbeenwidelycoveredprimarilyattheinterfacebetweentheaquaticandterrestrialboundaryandduringsaltingseason.However,theroleofchannelgeomorphicstructureonmechanismscontrollingtracemetalmobilizationandtransportinurbanstreamsunderbaseflowconditionsremainpoorlyresolved.Inthisstudyweaimedatprovidingaspace-resolvedanalysisoftracemetal(Cu,Cd,PbandZn)distributionbetweenpredominantly“mobilizable”and“non-mobilizable”fractionsinsuspendedsediments.Weinvestigatedthepossibleassociationbetweenconcentrationvariabilityinthesefractionsandstreamreachgeomorphologicalattributessuchassinuosityandhydraulicconductivity,in12reachesinthreeurbanwatersheds.Initialresultsindicatethathighlycomplexreaches(highlymeanderedwithgreaterriparianconnectivity)areassociatedwiththehighestconcentrationsofsaltcations,totalrecoverableandmobilefractionsofmetalelements.Thisstudyallowsforameaningfuldiscourseontheroleofstreamgeomorphologyontracemetaldistributioninsuspendedsedimentinsaltimpactstreamofhighlyurbanizedwatershedsandtheirsubcatchments.

Session4|LongTalksTheEffectofDogStranglingVineonInvadedCommunitiesDarwinSodhiIncreasedglobalizationhasledtothemovementandspreadofspeciesaroundtheworld,andthesespecieshavethepotentialtoprofoundlyalterecosystems.Theseinvasionsoftenresultinnegativeecological,economic,andhumanhealthimpacts.Vincetoxicum.rossicumisfoundinseveralecosystemssuchasopenmeadowsandunderstory,howeververylittleisknownabouthowitimpactscommunities.IhypothesizedthatV.rossicumwouldoccupysimilarnichespacetothatoftheresidentspeciesand,duetobothfitnessandnichedifferences,impactcommunitystructure.InanobservationalfieldstudyconductedintheRougeNationalUrbanPark;Canada’sfirstnationalurbanpark,IfoundthatinthemeadowecosystemV.rossicumhashighnicheoverlapandisselectingforspeciestobecomemoreabundant.However,intheunderstoryecosystemnicheoverlapcouldn’tbeconfirmedhowever,residentspeciesarebecomingincreasinglyspecializedinordertoavoiddirectcompetitionwithV.rossicum.

Theinfluenceofcurvatureonconvectioninatemperature-dependentviscosityfluid:implicationsforthe2Dand3Dmodelingofmoons JoshuaGuerrero Convection in terrestrial bodies occurswithin spherical shells described by the ratio, f, of their bounding radii.Previousstudiesthathavemodeledconvectionwithatemperature-dependentviscositynotedthestrongeffectoffontransitiontothestagnant-lidregime.Here,weanalyzestagnant-lidconvection(SLC)in2Dand3Dsystemswithcurvaturesincludingrelativelysmall-coreshells(fassmallas0.2)aswellasinthinshellandplane-layercases.Severalpeculiaritiesofconvectioninastronglytemperature-dependentviscosityfluidareidentifiedforbothhighandlowcurvaturesystems.WedemonstratethateffectiveRayleighnumbersmaydifferbyordersofmagnitudeinsystemswithdifferentcurvatures,whenallotherparametersaremaintainedatfixedvalues.Furthermore,asfisdecreased,thenatureofSLCinsmall-corebodiesshowsadivergenceinthetemperatureandvelocityfieldsfoundfor2Dannulusand3Dsphericalshellsystems.Inaddition,substantialdifferencesinthebehaviorofthinshell(f=0.9)andplane-layer(Cartesiangeometry)modelsoccurinboth2Dand3D,indicatingthatthelatter(emulatingatoroidaltopologyrather than spherical) may be inappropriate approximations for modeling variable viscosity convection in thinsphericalshells.Ourfindingsareespeciallyrelevanttounderstandingandaccuratelymodelingthethermalstructurethatmayexistinbodiescharacterizedbythinshells(e.g.,f=0.9)orrelativelysmallcores,suchasshellscomprisingtheGalileansatellitesandothermoons.Positiveselectionandred-shiftingsubstitutionsintherhodopsingeneofagloballydistributedfamilyoffishesmakingevolutionarytransitionsintofreshwater.AlexanderVanNynattenRhodopsin,thelight-sensitivevisualpigmentexpressedinrodphotoreceptors,isexquisitelywelladaptedforvisionindimly-litenvironments.However,rhodopsin’sabilitytodetectlightdiminishesunderwaterwherethevisiblespectrumnarrowswithdepth,unlessitssensitivitycoincideswiththewavelengthsoflightavailable.Indeep-seafishes,specificaminoacidsubstitutionsintheopsinproteincomponentofrhodopsinblue-shiftitspeakspectralsensitivitytomatchthewavelengthsoflightpenetratingdeepestinoff-shoremarinewaters.Incontrast,coastalregionsandlargeriversaremoreturbidandtanninstained;red-shiftingtheunderwaterlightenvironment.Themolecularmechanismsinvolvedinadaptationtored-shiftedwatershasnotyetbeenwellestablished.Wecomparedratesofmolecularevolutioninrhodopsinsequencesofagloballydistributedfamilyoffishesinhabitingoff-shore,coastalandfreshwaterhabitats.Wefindpositiveselectioninrhodopsin,consistentwiththediversearrayofvisualenvironmentsthesefishesinhabit.Modelscomparingphylogeneticpartitions,separatingmarineandfreshwaterlineages,indicatedN/dSishighestalongthetransitionalbranchfrommarinetofreshwaterinSouthAmerica.Thisbranchrepresentsthemostsubstantialred-shiftinenvironmentallightconditionsandincludedamongthepositivelyselectedsitesarered-shiftingsubstitutionsF261YandS124A.Recreatingtheseandothersubstitutionsonthebranchinvitroindicatesthefreshwaterlineageshaveared-shiftedrhodopsinpigmentcomparedtothemostrecentmarineancestor.Thisred-shiftedrhodopsinpigmentismoresensitivetothewavelengthsoflightpenetratingdeepestinAmazonianrivers,providingaclearadaptiveadvantagetothisancestrallymarinecladeoffreshwaterfishes.

SellingSuccess:PortrayalsofinvasivespeciesmanagementandthepotentialtounderestimateriskNoelleStratton,NicholasMandrak,NicoleKlenk

TheGreatLakesareofenormousecologicalandeconomicimportancetoCanadaandtheUnitedStates.Unfortunately,theregioniscurrentlythreatenedbyatleast188non-nativespecies.TheSeaLamprey,isanectoparasitethathasbeenlongestablishedthroughouttheGreatLakesandhadtremendousnegativeimpacts.SeaLampreymanagementiscurrentlyestimatedtocost$20millionperyear,andthisisonlyoneofthe188non-nativespecies.DespitetheinabilitytodatetoeradicatetheSeaLampreythreat,theGreatLakesFisheryCommissionhasdeclaredtheseeffortstobea“remarkablesuccess”.TheirgoalwasclearlytodemonstratetostakeholdersthatmanagementeffortsarehavingclearimpactsonSeaLampreyabundanceandmovementintheinterestofcontinuingthishighlyeffectivemanagementprogram.However,doesthistypeofphrasinggiveafalsesenseofourabilitytocontroltheimpactsofotherinvaders?Doweriskimplyingthatthethreatisover?Arewegivingtheimpressionthatifwesimplyhadtheresources,wecouldmanageanything?And,howmightthisinfluencethesenseofurgencytowardfutureinvaders?Giventheimportanceofearlydetectionandrapidresponsetoefficientandcost-effectiveinvasivespeciesmanagement,anyminimizationofthethreatofinvasivespeciesinthemindsofstakeholderscouldbedisastrous.Byoversellingoursuccesses,areweundersellingtherisks?Inthistalk,IwillexplorethesequestionsinordertoframemycurrentPhDresearchobjectives,andthequestionsIintendtoexploregoingforward.

PostersSessionLocomotoragilityandhearingsensitivityreconstructionfromtheinnerearofCantiussp.RajBhagat,MaryT.SilcoxThemorphologyofthemammalianinnerearisfunctionallyrelatedtocertainaspectsofecologysuchasananimal’stypeoflocomotionandhearingcapabilities.Thesepatternsareusefulinpaleontologytoreconstructbehaviouralinformationfromfossils.Here,wereconstructlocomotoragilityandhearingsensitivityfromtheinnerearoftheadapoidprimateCantiussp.(DMNSEVP124767).Cantiussp.belongstotheinfraorderAdapiformes,agroupofeuprimatesthatlivedintheEoceneofNorthAmerica,Europe,AsiaandAfricastartingabout56Ma.DMNSEVP124767wasfoundintheBighornBasin,Wyoming,duringthe2017fieldseasonoftheSilcoxLab(UTSC)andfieldpartners.Itincludesassociateddentalandneurocranialfragments.AhighresolutionmicroCTscanrevealedthepreservationoftherightinnerearincludingthelateralandposteriorsemicircularcanals(SSCs)andthecochlea(Figure1).ThedimensionsoftheSSCscanbeusedtoreconstructagilityandinferlocomotorbehaviourwhilecochleardimensionscanbeusedtoestimatehearingsensitivity.

Intermsoflocomotorbehaviour,NorthAmericanadapoids(i.e.,notharctids)aregenerallyconsideredtobearborealwithsomepropensitiesforleaping.TheagilityscoreofDMNSEVP124767iscalculatedtobe2.9(basedonthelateralSSC),whichsuggestsithadmediumslowagility.OurresultsareinlinewithapreviousstudythatreconstructedCantiusnuniensisashavingthesameagilityscore(2.9).Othernotharctidswerefoundtohavehigherscores,inthemedium-mediumfastrange.ThiscontrastissurprisingconsideringthepostcraniaofCantiusdisplayssomeadaptationsforleaping,whichisgenerallyconsideredanagilelocomotormode.Ourresultsmaysupportpreviousspeculationsthatthegenushadlesserpropensitiesforleapingthanothernotharctids.

Fewstudieshavelookedathearingsensitivitiesinadapoids.TheEuropeanadapoidAdapissp.isconsideredtohavehearingsensitivitiesof20.7dBforhighfrequencysounds(32kHz)and35.5dBforlowfrequencysounds(250Hz).Thehearingsensitivityofpreviouslystudiednotharctidsforlowfrequencysounds(250Hz)isintherangeofAdapissp.,althoughsensitivityforhighfrequencysoundsisunknown.DMNSEVP124767providesthefirstestimateforhearingsensitivityathighfrequenciesinnotharctids.Cantiussp.hadahearingsensitivityof25.2dBforhighfrequencysounds(32kHz)and38.8dBforlowfrequencysounds(250Hz).Itshearingfrequencylimitsareintherangeofotheradapoidsincludingitshighfrequencylimit.Theseresultsareinlinewiththeunderstandingthatearlyeuprimatesstartedtodevelopbetterperceptiontohighfrequencysoundsandaslightreductionintheperceptionoflowfrequencysoundsrelativetoprimitivestemprimates.Insum,theseresultshelptoprovideadditionalcontexttotheearlyevolutionofthegroupthatincludesalllivingprimates.

ForestmanagementpracticesaltersoilorganicmatterdegradationandcompositionintheSilvicultureTreatmentsforEcosystemManagementintheSayward(STEMS)experimentalforestB.F.Sultani

Forestmanagementpracticessuchasclear-cuttingfortheproductionoftimberinforestsareecologicallydisruptiveandmayresultinthelossofsoilcarbon.Greentreeretention(GTR)isanemergingsilviculturetreatmentthatretainsaportionofforestcoverwhichincludesdispersedandaggregateretention.However,molecular-levelanalysisofsoilorganicmatter(SOM)ofGTRmethodsislacking.Westudiedthemolecular-levelrootdecomposition(inlitterbags)andtheSOMprofilesoftwodifferentGTRforestpractisesaswellasclear-cuttingattheSnowdenDemonstrationForestinVancouverIsland,BC.Soilsamplesweretakenadjacenttothelitterbagsafter12monthsofdeployment.SOMbiomarkersweresubsequentlyanalysedwithgaschromatography-massspectrometrywhichtargetscompoundsderivedfromcutin,suberin,ligninaswellasvariouslipids.Inaddition,soilandrootsampleswerecharacterizedusingsolid-state13Cnuclearmagneticresonance(NMR).Resultsshowedthatamongdifferenttreatments,similarplant-derivedinputswereidentifiedbutvariedinconcentration.Theinputofplant-derivedcompoundssignificantlyalteredSOMcompositionandenhancedtheturnoverofsoilC.AnalysisofSOMcompositionwillassistwiththedevelopmentofstrategicandeffectiveforestmanagementpracticesasSOMisanimportantfactorregulatingcarboncycling.Investigationintothepost-translationalregulationofproteasomecomplexassemblyinArabidopsisthalianaduringabioticstressesDianaBoneaCellularproteinsmayundergomisfolding,denaturation,oxidationandaggregationinunfavorableenvironments.Thebuildupofdysfunctionalproteinsismitigated,inpart,bydegradationandrecyclingviatheubiquitin-proteasomesystem.Underthissystem,substratestaggedwithpolyubiquitinchains(byenzymesE1,E2,E3)aretargetedforhydrolyticbreakdownbythe26Sproteasome,whichiscanonicallycomposedofa19Sregulatoryparticle(RP)anda20Scoreparticle(CP).WhilemanystudieshighlighttheimportanceofE3ligasesintargetingregulatoryproteinsfordegradationduringplantstressresponses,littleisknownabouttheregulationofthe26Scomplexitself.Inthisstudy,weaimtoinvestigatehowthestoichiometryofproteasomeassemblyimpactstheabioticstressresponse.UsingA.thalianaseedlingsthatweretransientlyexposedtohighheat,oxidative,osmoticandsaltstress,wefoundthattheproteasomeundergoespost-translationalstructuralregulationthatalterstheratioofRP1-CP,RP2-CPandCPaloneintotallysates.ImmunoprecipitationofPAG1-FLAG,asubunitoftheCPthatco-purifiesRP,hasverifiedourfindingsandalsogivesusapotentialmeansofdetectingnovelinteractorsthatassistinstructuralremodelingoftheproteasome.BioinformaticsanalysishasrevealedputativeA.thalianaorthologsofatleast10yeastchaperonesthatarecriticalinproteasomeassembly.WehaveobtainedT-DNAinsertionsinthecorresponding10genesandwilltestwhethersomeoftheseassemblyfactorsdirectlyfunctiontoremodeltheproteasomeduringstressadaptation.

Rolesofinfralimbicandprelimbiccorticesincontextualbiconditionaldiscriminationmemoryretrieval.SadiaRiaz,PugaliyaPuveendrakumaran,DinatKhan,SharonYoon,RutsukoIto.Thetwosubdomainswithinthemedialprefrontalcortex(mPFC),infralimbic(IL)andprelimbic(PL),havebeenshowntodifferentiallycontrolcontext-dependentbehaviour.WhileactivityinthePLhasbeenshowntopromotetheexpressionofconditionedfearanddrugseeking,ILactivationhasbeenassociatedwiththeextinctionandinhibitionofthesebehaviours.Yet,thepotentialrolesofthePLandILincontextuallydrivennaturalrewardseekingremainunderexplored.ThepresentstudysoughttofurtherexaminethefunctionaldichotomyofthemPFCincontextualcontroloverappetitivelymotivatedbehaviour,employingacontextualbiconditionaldiscrimination(CBD)taskincombinationwithtemporarypharmacologicalinactivation.Tothisend,adultmaleLongEvansratsreceivedCBDtraininginvolvingthesequentialpresentationoftwodistinctauditorystimuli(X,Y)intwodifferentcontexts(A,B;differentsize&odor).Ratsweretrainedtonosepokeinresponsetothepresentationofonestimulusforthedeliveryofsucroserewardandtowithholdanosepokeresponsetothepresentationofthesecondstimulusinacontext-specificmanner(e.g.AX+,AY-;BX-,BY+).Followingacquisition,ratsreceivedanintracerebralmicroinjectionofacocktailofGABARagonistsorsalineintothePLorIL,priortoundergoingaCBDtrainingsessionandanextinctiontest.Contrarytoexpectation,bothILandPLinactivationresultedinrobustimpairmentinCBDmemory,indicatingthatbothregionsarenecessaryfortheprocessingofappetitivelymotivatedcontextualmemoriesinnaturalrewardseeking.DissociativeeffectsofdorsomedialstriatumD1andD2receptorantagonismintheregulationofinnateandlearnedapproach-avoidanceconflictdecision-makingDavidNguyen,ErindAlushaj,SuzanneErb,&RutsukoItoThestriatumiswidelyimplicatedinthetranslationofmotivationintogoal-directedbehavioraloutput.WehaverecentlyshownthatdopaminergicD1(D1R)andD2receptors(D2R)intheventralaspectofthestriatumexertdissociablecontrolovercue-elicitedapproach-avoidancedecision-making,inthepresenceofconflictingmotivationalforces.Thedorsomedialstriatum(DMS)hasalsobeensuggestedtobeinvolvedincost-benefitconflictprocessing,butthecontributionoftheregion’sdopaminergicreceptorsremainsunexplored.Tothisend,weutilizedaneuropharmacologicalapproachtoinvestigatetherolesofDMSD1RandD2Rinregulatingcue-elicitedandinnateapproach-avoidancedecision-making.Usingaconditionedmixed-valenceconflictparadigm,weinitiallytrainedratsinathree-armradialmazetoassociatevisuotactilecueswithappetitive,aversive,andneutraloutcomes.Ratsthenreceivedanintra-DMSmicro-infusionofD1Rantagonist,SCH23390,orD2Rantagonist,sulpiride,andwerethentestedfortheexpressionofapproach-avoidancebehaviorinaconflictscenario,whereintheappetitiveandaversivecuesweresuperimposedwithinasinglemazearm.TheresultsrevealedthatDMSD1RantagonismsuppressedapproachtowardstheconflictarmwhileDMSD2Rantagonismenhancedapproach.NeitherD1RnorD2RantagonismintheDLShadaneffectonapproach-avoidanceconflictbehavior.Allratsalsounderwenttestinginanelevatedplusmazetest,asameasureofinnateapproach-avoidanceconflict(anxiety).DMSD1Rantagonismdecreasedanxiety,whileDMSD2Rantagonismincreasedit.BothD1RandD2RantagonismintheDLSelicitedananxiogeniceffect.Together,ourfindingssuggestadissociationintheroleofDMSD1RandD2Rinregulatinglearnedapproach-avoidancedecision-making,andrevealadorsalstriataldopaminergicmechanismintheexpressionofinnateanxiety.

TheRoleofEcologicalDifferentiationinAcceleratingTraitEvolutioninNeotropicalBirdsVanessaLuzuriaga-AveigaThe importanceofecologicalopportunity inpromotingspeciationhasbeenstressedathigh latitudesand islandecosystems,butourunderstandingofwhetherecological-mediateddivergentselectionacceleratestheprocessofspeciationremainspoorlystudiedinthetropics.Iperformedamacroevolutionaryanalysisoftraitdivergenceacross135closelyrelatedpairsofpasserinebirdspecies fromtheAmazonbasinandadjacentAndeanslopestoassesswhetherthedifferenceinelevationalrangeseparatingspeciespairs influencesthespeedoftraitevolution.Traitdivergenceinelevationwasusedasaproxyforthedegreeofecologicaldivergence.Myresultsdemonstratethatthedegreeofelevationalseparationisassociatedwithfasterdifferentiationofsongfrequency–atraitimportantforprematingisolation–andseveralmorphologicaltraits–whichmaycontributetoextrinsicpostmatingisolation.These latter,suggest thatecologicaldifferentiationhasplayedapivotalrole inacceleratingratesofevolution intraitsimportantforspeciationinAndes.TheFunctionalSegregationoftheDentateGyrusinLearnedApproach-AvoidanceConflictDecisionMakingYeates,DylanCM;Ussling,Alicia;Lee,AndyCH;Ito,Rutsuko

Approach-avoidanceconflictsoccurwhenorganismsfacesituationsthatsignalopposingaffectiveoutcomes,andmustchoosetoeitherengageordisengage.Itisincreasinglyacknowledgedthatthehippocampus,particularlyitsventralaspect,ispartofacriticalnetworkinvolvedinrecognizingandresolvingapproach-avoidanceconflicts.Lessisknownabouthowtheventralhippocampus’subdivisionsalongitstransverseaxismediateaffectiveconflicts.UsingtransientpharmacologicallesionsinLong-Evansrats,thepresentstudyobservedthattemporaryinactivationoftheventraldentategyrusresultedinincreasedapproachestowardsaffectivelyconflictinginformationdespitealsobeingassociatedwithaversiveoutcomes,andwithoutaffectingspatialmemory.Incontrast,dorsaldentategyrusinactivationsdidnotresultinchangestoapproach-avoidanceconflictresolutionbutdidimpairspatialmemory.Thesefindingssuggestthatthedentategyrusisfunctionallydissociablealongitslongitudinalaxis,withitsventralpartservingasacriticalactorinresolvinglearnedapproach-avoidanceconflicts.DifferentialmechanismsofbacterialadhesioninresponsetosubstratestiffnessZayadi,Alexa;Hengge,Regine;Sullan,RubyM.A.Biofilmsconferbacterialresistancetoantimicrobialagentsandhostdefensesand,oncemature,aredifficulttoeradicatemakingpreventionofbiofilmformationtheoptimalmitigationstrategy.Biofilmsbeginwithbacterialadhesiontoasubstrate,mediatedbystickycellsurfaceappendagesincludingflagellaandtype1fimbriae.Recentevidenceindicatesbacteriacanusesurfaceappendagestosenseandrespondtothepropertiesofanunderlyingsubstrate,includingitsstiffness.Understandingthemolecularmechanismsofstiffness-dependentadhesionisanimportantpartofinformedmaterialsdesignandselectionforsurfacesvulnerabletobacterialcolonization.Inthiswork,theextentofadhesionbyisogenicEscherichiacolimutants,eitherlackingflagellaorlackingtype1fimbriae,isshowntodifferentiallydependonthestiffnessoftheunderlyingsubstrate.