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  • AbstractBook

    2016SpringMeeting

    March31April2,2016

    TBarMResortandConferenceCenter

    2549Highway46West,NewBraunfels,Texas

  • UndergraduateStudentOralPresentations

    1. AntibacterialActivityofPlantExtractsonPseudomonasaeruginosaChristopheChahineStEdwardsUniversity

    The bacterium, Pseudomonas aeruginosa is categorized as nosocomial and opportunistic,meaning that it frequently infects patients in hospitals especially thosewith some underlyingcondition. Ithasarelatively impermeableoutermembranemaking it lesssusceptible tomanyantibiotics.However,ifaharmfulmoleculedoesenterthecell,thenauniqueeffluxpumpmayquicklyexpel it.P.aeruginosacanalso formaprotectivebiofilmwhich furtherprotects it fromantibiotics.Approximately2millionAmericansbecomeinfectedwithantibioticresistantbacteriaannually, resulting in approximately 23,000 deaths. To provide new antibiotic alternatives oradditives, the use of natural substances that have antibacterial properties would be a goodchoice.This researchanalyzedplantextracts for theirpossibleantibacterialproperties. In thisresearch,88typesofplantextractswereincubatedinethanolsolution,usedtosaturateapaperdisk, and the disks placed onMuellerHinton agar plates inoculatedwith a suspension ofP.aeruginosa.Noneof theplantextracts testedresulted in the inhibitionofP.aeruginosa. Twoplantextractsthatshowedpromisefromapreviousstudywerealsotestedforinhibition.Virolasebifera previously inhibited Staphylococcus aureus and Daviesia quadrilateral previouslyinhibitedChromobacterviolaceum.Whentestswereperformedtoconfirmthesepreviousdata,no inhibitionwasdetected. It is possible that therewere inconsistencies in theexperimentalmethodsormisinterpretationoftheresults.Forfurtherresearch,additionalplantextractsshouldbe tested. If any plant extract shows bacterial inhibition, then determining and isolating thechemicalcompound(s)responsiblewouldbethenextstep.

    2. Testingplantextractsforantiquorumsensingactivity.MalaysoneChongFoungandPatriciaBaynham,PhDStEdwardsUniversity

    Thereareapproximately2millionpeopleinfectedwithantibioticresistantbacteriaintheUnitedStates,andatleast23,000deathsreportedannually.Thereisanecessitytodevelopnewdrugsas a solution to antibiotic resistance threats. Previous studies showed that targeting thechemical communication known as quorum sensing or QS, which is a bacterial networkingbehavior,couldbeaneffectiveapproach.InQS,bacteriaareabletosensethedensityoftheirownspeciesandcanthenundertakegroupbehaviorswhenthebacterialpopulationdensityishigh.ProcessescontrolledbyQSincludeproductionofaprotectivebiofilmortoxinproduction,whichareactivitiesthatmakebacteriamoredangerous.IfQSinhibitorsorQSIscanbefound,thesemaymakebacterialesspathogenic.Inthisresearch,variousunknownplantextractsfromPeru were tested for their ability to inhibit QS activity using the pigment production inChromobacterium violaceum as a model for detecting QSIs. Out of the 88 unknown plantextracts, one showedQSI, so the next step in this research will be to request an additionalsampleof theseextracts, for further testingwithpathogenicbacteriasuchasEscherichiacoli,Pseudomonas aeruginosa,Staphylococcus aureus andEnterococcus faecalis. We can thenfind the minimum inhibition concentration and determine the mechanism of action. If thisresearchissuccessful,thiscouldleadtothecreationofanewdrug,whoseapplicationwouldbeanewweaponagainstantibioticresistantbacteria.

    3. ThePursuitforNovelAntibiotics

  • FashakinSarahBaylorUniversity

    AccordingtotheCentersforDiseaseControlandPrevention(CDC),almosttwomillionpeopleare infected with antibiotic resistant bacteria, and over 23,000 of those people die. Thisantibioticresistancethreatisbecomingmoreprevalent,especiallyinthesixmultidrugresistantbacteriaknownastheESKAPEpathogens.Thesepathogensinclude:Enterococcusfaecalis,Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonasaeruginosa,andEnterobactercloacae.Oneplanofaction that theCDCsuggested tocombatthisissuewastodevelopnovelantibiotics.Inlightofthis,YaleUniversity,in2012,establishedtheSmallWorld Initiative (SWI),an innovative researchprogram that iscommitted to tacklingthis global health issue of the declining number of effective antibiotics by encouragingcrowdsourcingantibioticdiscoverythroughresearch.Statisticshavealsoshownthattwothirdsof antibiotics originated from the soil evidently because that is where most of the microbialwarfareoccurs.So,theSWIspotlightsthesoilasthebasisofitsresearch.UsingsoilcollectedfromCameronPark,Waco,TX,we(myresearchpartner,andI)successfullyisolatedabacterialstrain of the Pseudomonas genus that showed some antimicrobial action. We employeddifferenttechniques,liketheKirbyBauermethod,anddifferentbiochemicalteststogarnermoreinformation,andunderstandingofthisorganism.Thebiochemicaltestsshowedusthatitwasofthepseudomonasgenus,andsodid theBasicLocalAlignmentSearchTool (BLAST)results.What we were not able to figure out was the species it belonged to. Although four likelycandidates that closely resembled this organism according to BLAST were: PseudomonasmosseliistrainCFML9083,whichhadonegap,andanidentityscoreof1266/1267(99%).Thisspecies was extracted from human blood in France. Another prospective match wasPseudomonasmonteilii,whichhadzerogapsandanidentityscoreof1264/1267(99%).Itwasalsoisolatedfromclinicalsamples,butfromDenmark.PseudomonasentomophilastrainL48isalsoapossibilitywithzerogaps,andanidentityscoreof1264/1267(99%).Itwasisolatedfromsoil in France, making it a better candidate than those that were mentioned previously.Pseudomonas taiwanensis strain BCRC 11751 had zero gaps, and an identity score of1264/1267(99%). We also used the Automated Biometric Information System (ABIS) tocomparethebiochemicaltestresultsofourorganismwiththoserecordedforthesecandidates,andwefoundthesimilarityevenmorestriking.Thismadeithardtonarrowdownourorganismsspecies. From the KirbyBauer method results, our organism showed some resistance toantibiotics like penicillin, erythromycin, and sulfamethoxazole. The high antibiotic resistanceobservedinoursoil isolateischaracteristicofthePseudomonasgenus,whichisknowntobehighly competent. However, we also noticed sensitivity to ciprofloxacin. This sensitivity, webelieve,isawindowtoabreakthroughfinalsolutiontothispresenthealthmenace.

    4. Myxococcus xanthus Social Motilitydriven Colony Expansion is Dependent on CellDensity,ExopolysaccharideDeposition,andNutrientExposure

    KimberleyKissoon1,IsabelCornejo2,PintuPatra3,OlegIgoshin3,andHeidiB.Kaplan41DelMarCollege,CorpusChristi,TX2UniversityofHoustonDowntown,Houston,TX3RiceUniversity,HoustonTX4TheUniversityofTexasMedicalSchoolatHouston,HoustonTX

    Social (S) motility is the type IV pili (TFP)mediated flagellaindependent group movementexhibited by the gramnegative soil bacterium Myxococcus xanthus on solid surfaces. ThebindingofTFP toanexopolysaccharide (EPS)coatedneighbouringcell isknown tostimulatethe pilus retraction required for this motility. Previous results examining the expansion of Smotilecoloniesat24hrevealedacelldensitydependence,inwhichcolonieswithhigherinitial

  • cell densities expandedmore rapidly.Wepropose that there is a direct relationship betweencellgenerated EPS deposition and colony expansion. To test this hypotheses, we firstdevelopedamathematicalmodelbasedonFischersequation thatpredicts theeffectsofcelldensity,EPSdeposition,andnutrientexposureonthecolonyexpansionrate.Specifically,ourmodel predicts that at low initial densities,more time is required for the cells to accumulateenough EPS to activate Smotility resulting in a longer lag period. Furthermore, our modelmakesthenovelpredictionthatafterthelagphase,thepopulationwillexpandataconstantrateindependentofthecelldensity.Weexperimentallytestedthemodelbymeasuringthelongtermcolony expansion dynamics of Smotile cells. Liquid cultures ofM. xanthus DK1218, a strainexhibitingonlySmotility,weregrown,dilutedtodifferentdensities,and3ldropswerespottedontoagarplates.Theplateswereincubatedat32Cinahumidchamberforupto96h.Eachspotwasimagedwithadissectingmicroscope,andthedistancemovedbythecolonyedgewasmeasured at 2 h, 4 h, 6 h, 8 h, and least twice a day for up to four days. Under standardconditions (1% casitone 0.5% agar), as expected, the higher density colonies hadproportionallyshorterlagperiods,expandedmorerapidly,andtravelledfarther.However,underthese conditions at all densities the expansion rate decreased over time, deviating from themodelspredictionofa constantexpansion rate.To identify conditions resulting inaconstantexpansionrate,wetestedplateswithvariousagar(0.3%,0.4%)andnutrient(0.5%,1.5%,2%casitone,1%casitonewith0.2%yeastextract)contents.Onlythehighestnutrientplates(0.2%casitone, 1% casitone with 0.2% yeast extract) allowed for constant expansion. These datasupportandconfirmourmodelspredictionsthatexplain thedependenceofcolonyexpansiononcelldensity,EPSdepositionandnutrientexposure.

    5. InvestigatingUniqueGenomicFeaturesofRareClusterMMycobacteriophages in theNovelPhageNanosmite

    ReavelynM.Pray,R.DeborahOverath,DaiyuanZhang,J.RobertHatherhillDelMarCollege

    Phagesareancientbutpoorlyunderstoodandhave largeamountsofgeneticdiversity.Somephage genomes are better understood than others due to higher abundance of genomicsequencing.Thereareover7000sequencedActinobacteriophage1,129ofwhichareknowntoinfectMycobacterium spp.. Mycobacteriophages are separated into clusters based on theirsequencehomologyandthenfurthersegregatedintosubclusters.ClusterMcurrentlyhasonlynine members, with newly sequenced Nanosmite being assigned to its own subcluster.MycobacteriophageNanosmitewasisolatedfromapublicsystemwaterwayandsequencedin2015.ClusterMphagesareknownfortheirremarkablecollectionsoftRNAisotypes,whichmaybe important to complete late lytic cycle growth. Cluster M phage also carry a collection ofgenes fromMycobacteriumabscessus,aclose relative toMycobacterium tuberculosum. Thisrapi