微生物生态学课件Heavymetalsbeingtransferredtohumansviathefoodchainwouldfinallythreatenhumanbeingshealth.Growinplantrootsystem.Withbacteria,actinomycetes,fungi,algae,andtheprotozoa.Alternaterelationshipbetweenthemandplant.Plantrootsinteractionandpromoteeachother.Bacteria8大家学习辛苦了，还是要坚持CyanobacteriaFungiSaccharomycesCerevisiaeAlageScenedesmusObliquusAkindofparasiticbacteriainplantbody,allplantshaveendophytes.Endophyticbacteria(PGPB)isakindofparasiticlife,promotethegrowthofthehost.Canenhanceplantresistancetopathogens,drought,heavymetal.FromElsholtziasplendensandduckplantargrass(Commelinacommunis).Firmicutes,Actinobacteria,Proteobacteria.Thesebacteriastrainsincopperresistanceofmaingroups.TheCr6+resistantplantgrowthpromotingbacteria(PGPB),Pseudomonassp.PsA4andBacillussp.Ba32wereisolatedfromheavymetalcontaminatedsoilsandtheirplantgrowthpromotingactivityontheIndianmustard.Mechanismsofresistencetoheavy-metalReducetheabsorptiontheheavymetalcontentinthemicrobialcellsatalowlevelismaintainedwithoutcausingtoxiceffectsoncells.AsatypeofstaphresistanceofCd2+isthecase.Increasethedischargesomemicroorganismsmaybeproactivemannerbyheavymetalionswithinthecellisdischargedoutsidethecell,thusmaintaininglowlevelsofthecell.AsonekindofresistancetoBacilluscopper.Oxidationreductionmanymicrobialoxidationorbyreduction(inmostcases)fromthehightoxicityoftheheavymetaltransformedintolesstoxicvalencevalencestate,therebyliftingtheheavymetaltoxicity.Forexample,theresistanceofmercurythatisthecase.BondedtotheoutercellsReducingtheconcentrationoftoxicheavymetalsintheenvironment,thepurposeofdetoxification.Escherichiacolicopperresistanceeffectasthatisso,itcanbesecretedproteinscapableofbindingtocopperions,therebyreducingtheeffectiveconcentrationofcopperions.AdsorptionManymicrobialcellsurfacehasaspecialstructure,canabsorbheavymetalionsandthustoreducetheconcentrationofheavymetalionsinsolution.CurrentresearchprogressCr-resistantstrainsPseudomonassp.PsA4andBacillussp.Ba32appliedt