BiochemicalmechanismsofpathogenrestrictionbyintestinalbacteriaKavitaJ.Rangan1andHowardC.Hang1,*1LaboratoryofChemicalBiologyandMicrobialPathogenesisAbstractTheintestineisahighlycomplexecosystemwheremanybacterialspeciesinteractwitheachotherandhostcellstoinfluenceanimalphysiologyandsusceptibilitytopathogens.Genomicmethodshaveprovidedabroadframeworkforunderstandinghowalterationsinmicrobialcommunitiesareassociatedwithhostphysiologyandinfection,butthebiochemicalmechanismsofspecificintestinalbacterialspeciesareonlyemerging.Inthisreview,wefocusonrecentstudiesthathavecharacterizedthebiochemicalmechanismsbywhichintestinalbacteriainteractwithotherbacteriaandhostpathwaystorestrictpathogeninfection.Understandingthebiochemicalmechanismsofintestinalmicrobiotafunctionshouldprovidenewopportunitiesfortherapeuticdevelopmenttowardsavarietyofinfectiousdiseases.Emergingmechanismsandapplicationsofmicrobiota-mediatedpathogenresistanceTheintestinalmicrobiota(seeGlossary)iscentraltohostmetabolismandimmunity[1,2].Asaresult,themicrobiomeasawholebroadlyimpactshostphysiologyandresponsetointestinalandsystemicdiseases.Thecompositionoftheintestinalmicrobiomeisdynamicandisinfluencedbyenvironmentalfactorsincludinghostdietandexposuretodrugs,infection,andprobiotics,aswellasbygeneticfactors.Advancesinourunderstandingofspecificbacterialgenesandmoleculeshaverevealedadiversityofinter-bacterialinteractionsandimmuno-modulatoryrolesforintestinalbacteriathatinfluencepathogenfitnessandhostresponsetoinfection[3].Thisreviewwillfocusonrecentstudiesofspecificintestinalbacterialspecies,theirmetabolitesandpotentialbiochemicalmechanisms(seeTable1forexamplespresentedinthisreview).Beyondinfection,theintestinalmicrobiomewidelyinfluenceshostphysiology,withspecificbacterialfactorscontributingtodiseasesincludingobesity,cardiovasculardisease,anddiverseneurologicaldisorders.Thesetopicshavebeenrecentlyreviewedelsewhere[4,5]andwillnotbediscussedinthisreview.Amolecularunderstandingofintestinalmicrobiota-hostinteractionsisofgr...
