极端微生物

Exploringresearchfrontiersinmicrobiology:recentadvancesinhalophilicandthermophilicextremophilesBeateAverhoff,VolkerMu¨ller*MolecularMicrobiology&Bioenergetics,InstituteofMolecularBiosciences,JohannWolfgangGoetheUniversityFrankfurt,Max-von-Laue-Str.9,60438,FrankfurtamMain,GermanyReceived25March2010;accepted11May2010Availableonline31May2010AbstractExtremophilicprokaryotesinhabitecosystemsthatare,fromahumanperspective,extreme,andlifeintheseenvironmentsrequiresfar-reachingcellularadaptations.Here,wewilldescribe,fortwoexamples(Thermusthermophilus,Halobacillushalophilus),howthermophilicorhalophilicbacteriaadapttotheirenvironment;wewilldescribethemolecularbasisofsensingandrespondingtohypersalinityandwewillanalyzetheimpactandbasisofnaturalcompetenceforsurvivalinhotenvironments.�2010ElsevierMassonSAS.Allrightsreserved.Keywords:Compatiblesolutes;DNAtransport;Extremophiles;Halophiles;Naturalcompetence;Thermophiles1.IntroductionExtremophilicprokaryotesarecharacterizedbyinhabitingecosystemsthatare,fromahumanperspective,extreme.SuchenvironmentsmayhaveextremelyhighorlowpH,highorlowtemperatures,highsalinity,highpressureandvariouscombi-nationsthereof.Extremophilicmicroorganismsincludemembersofallthreedomainsoflife,theArchaea,BacteriaandEukarya.Often,thesemicrobesarenotonlychallengedbyoneextreme,butmultiple,andthustheyare“polyextremophile”(MesbahandWiegel,2008).Exampleswouldbelifeathotalkalinespringsorhypersalineandalkalinelakesorhotandacidicsprings.Eversinceextremophileswerediscovered,theirphysiologyandtheiradaptationtotheunhostileenvironmenthaveattractedmuchinterest.Thiswasnotonlybecauseoftheinterestintheirlifestyle,butalsoforexploringtheirbiotech-nologicalpotential.TheenzymeTaqpolymeraseisaprimeexampleofanenzymefromanextremophile,Thermusaqua-ticus,isolatedin1969byThomasD.BrockandHudsonFreezefromthermalspringsinYellowstoneNationalPark(BrockandFreeze,1969).Thisenzymehasmadethepolymerasechainreactionpossibleonalarge,automatedscale.Withthisenzyme,sequencinggenomeswasmadepossibleanditg