英文文献报告

ReadingReportTheeffectofmixotrophyonmicroalgalgrowth,lipidcontent,andexpressionlevelsofthepathwaygenesinChlorellasorokinianaIF=3.425主要内容•本文围绕生物能源微藻的培养进行研究。对目的微藻进行培养优化，对微藻的光合自养、异养和混合培养对其生长、脂质影响进行比较和分析，认为混合培养即可以大量促进微藻的生物量的累积并提高微藻的脂含量，而且代价较异养要低，可以作为微藻大规模培养的可选择手段。且C.sorokinianaCCTCCM209220要优于另外两种微藻。•本文通过实时PCR，对（accD、acc1、rcbL）基因在C.sorokinianaCCTCCM209220中的表达量进行测试，并将表达差异和脂质含量进行比较，选出了和脂质含量密切相关的基因作为将来基因改造的候选基因。认为在非异养条件下，accD基因的表达水平可作为评估脂质含量的检验手段之一。ContentsIntroduction1.Results2.Discussion3.Benefits4.Introduction•Thesearchofanimprovedrawmaterialisoneofthemajorobjectivesinbiodieselresearch.•Microalgaehavemanyadvantagesfortheproductionofbiodieselcomparedtootheroilcrops.IntroductionThecultivationofmicrolagaedoesnotrequirelargeareasofarable.AdvantagesMicroalgaecangrowrapidly,andmanymicroalgaespeciesarerichinoils.IntroductionHeterotrophyMixotrophyPhotoautotrophyWithoutorganiccarbonsources.SlowgrowthLowestcostRelayonorganiccarbonsourcesFastgrowthHighestcostcomplementphotoautotrophywithorganicmaterialFastgrowthRelativelycheap•MixotrophicMixotrophiccultivationcancomplementphotoautotrophywithorganicmaterial,thusshorteningthegrowthcycle,increasingbiomassyield,anddecreasingthecostofheterotrophicmicroalgaecultivation.Introduction•Acetyl-CoAcarboxylase(ACCase)•Inthebranchpoint,acetyl-CoAcarboxylase(ACCase)cancatalyzeacetyl-CoAtobeconvertedtomalonyl-CoAandtoenterthepathwayoflipidbiosynthesis.Thisreactionisacriticalstepinfattyacidbiosynthesis,soACCaseisconsideredakeyenzymeforlipidaccumulation.IntroductionaccDheteromericacetyl-CoAcarboxylasebetasubunit.acc1homomericacetyl-CoAcarboxylasercbLribulose1,5-bisphosphatecarboxylase/oxygenaselargesubunitIntroductionIntroduction•Thispaperanalyzedtheexpressionofthreedifferentgenes(accD,acc1,andrbcL)inthisstrainunderdifferentmixotrophicconditionsbyreal-timePCR.Inordertostudygeneregulationrelatedtolipidsynthesis,andexaminedtherelativeexpressionofthreegeneswithrespecttogrowthandoilaccumulation,whichoffersusefulinsightsintosubsequentstepstoimprovethisparticularmicroalgalstrain.ResultsFig.1(a)GrowthcurvesofN.oculataCCMP525undermixotrophicconditionsEffectofmixotrophicconditionsonmicroalgalgrowthResultsFig.1(b)GrowthcurvesofD.salinaFACHB435undermixotrophicconditionsFig.1(c)GrowthcurvesofC.sorokinianaCCTCCM209220undermixotrophicconditionsResultsResultsFig2(a):LipidcontentofN.oculataCCMP525,D.salinaFACHB435,andC.sorokinianaCCTCCM209220undermixotrophicconditionsEffectsofmixotrophicgrowthonproteinandlipidcontentofalgalbiomassResultsFig2(b):ProteincontentofN.oculataCCMP525,D.salinaFACHB435,andC.sorokinianaCCTCCM209220undermixotrophicconditionsResultsResultsFig.3(a)TheglucoseremainsofN.oculataCCMP525inthemixotrophicmediumResultsFig3.(b)TheglucoseremainsofD.salinaFACHB435inthemixotrophicmediumResultsFig3.(c)TheglucoseremainsofC.sorokinianaCCTCCM209220inthemixotrophicmedium•EffectsofmixotrophicconditionsonoilcontentanddifferentialgeneexpressioninC.sorokinianaResultsResultsFig.4Quantificationoftheexpressionofpathwaygenes,accD,relatedwithlipidsynthesisinC.sorokinianaCCTCCM209220withdifferentglucoseconcentrationsResultsFig.4Quantificationoftheexpressionofpathwaygenes,acc1,relatedwithlipidsynthesisinC.sorokinianaCCTCCM209220withdifferentglucoseconcentrationsResultsFig.4Quantificationoftheexpressionofpathwaygenes,rbcL,relatedwithlipidsynthesisinC.sorokinianaCCTCCM209220withdifferentglucoseconcentrationsResultsFig.5LipidcontentofC.sorokinianaCCTCCM209220duringdifferentpopulationgrowthperiodsundermixotrophicconditionsDiscussion•Highlipidproductivityisakeycharacteristicofanalgalspeciesforbiodieselproduction.Inthisstudy,C.sorokinianaCCTCCM209220hasexhibitedarapidgrowthrateandhighoilcontentwhenculturedinmixotrophicconditionandthuscanbeconsideredasapromisingcandidatespeciesthatmayinthefuturebegeneticallymanipulatedtoimproveoilyieldfurther.Discussion•Mixotrophiccultivationisaneffectivemethodtoobtainhighmicroalgalbiomassproductivity;furthermore,mixotrophycanbeneficiallyaffecttheproteinandlipidcontentofthisbiomassatleastforspeciessuchasC.sorokiniana.Arendofincreasedlipidandproteincontentwasobservedperhapsbecauseglucoseprovidesadditionalenergyandmaterialforbiosynthesis.Discussion•HeteromericACCase(accD)isoneofthekeyenzymesrequiredforthesynthesisoffattyacids.•Inthisstudy,expressionlevelsofthegeneshowedlittlecorrelationwithlipidcontentasexpressionlevelsofacc1wereconsistentlylowineachculture.•Thus,therbcLgenewasusedtoexaminefortherateofphotosynthesisinthestudy.Inparticular,theexpressionlevelsoftherbcLgeneinlogarithmicphaseofphotoautotrophicculturegreatlyexceededthosefoundinmixotrophicculture.