1) Based on my lectures and the assigned paper Does the evidence suggest that peroxisomes were acqu

1) Based on my lectures and the assigned paper: Does the evidence suggest that peroxisomes were acquired at the same time and by the same mechanism as mitochondria and chloroplast? After you answer your question with a distinct Yes or No, THEN explain your answer. (10 points)2) Why do peroxisomes from many different classes of organisms have similarcharacteristics? Be certain to include the evolutionary aspects in your answer – in fact this is the key point of this question so don’t digress too far from the key point. (8 points)3) Why do peroxisome from many different classes of organisms have different characteristics? Be certain to include the evolutionary aspects in your answer – in fact this is the key point of this question so don’t digress too far from the key point. (5 points)4) Is there a relationship between peroxisomes and the endoplasmic reticulum? First clearly answer Yes or No. THEN explain your answer. (5 points)5) What role does removal of the cell wall have in the formation of the peroxisome when you consider this putative evolutionary process? (5 points).Peroxisome Diversity and EvolutionAuthor(s): Toni GabaldónSource: Philosophical Transactions: Biological Sciences, Vol. 365, No. 1541, Evolution ofOrganellar Metabolism in Unicellular Eukaryotes (Mar. 12, 2010), pp. 765-773Published by: The Royal SocietyStable URL: http://www.jstor.org/stable/40538242 .Accessed: 19/09/2014 14:04Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact support@jstor.org..The Royal Society is collaborating with JSTOR to digitize, preserve and extend access to PhilosophicalTransactions: Biological Sciences.http://www.jstor.orgThis content downloaded from 149.169.115.181 on Fri, 19 Sep 2014 14:04:58 PMAll use subject to JSTOR Terms and ConditionsPHILOSOPHICALTRANSACTIONSof*T%R.Phil.Trans. Soc. B (2010) 365,765-773doi:10.1098/rstb.2009.0240THE ROYALW’SOCIETY JLßReviewPeroxisome diversity and evolutionToni Gabaldón*88Centre Genomic(CRG), Dr Aiguader, 08003 Barcelona,SpainRegulationforofinthatmembrane can be found all majorbounded a singlearePeroxisomes organdíesgroupsbyinis supported thepresence,cellularAbycompartmentevolutionary ofthisorigineukaryotes.singleandinsetofdiversebiogenesis maintenance.implicated peroxisomeorganisms, a common ofproteinsofalevel evolacrosscanTheirhowever, varyindicatinghighcontent,substantially species,enzymaticinonourknowledge peroxisomes somehavegreatlyProteomicexpandedanalysesutionaryplasticity.wehavea limitedandmammals yeasts.modelorganisms,However, stillknowledgeincludingplants,ofofinofperoxisomes thevastmajority groups microbialandaboutthedistribution functionalitiesandofrecentadvancesin our understanding peroxisomediversityHere, I revieweukaryotes.inonwitheukaryotes.evolution, a specialemphasis peroxisomes microbialevolution;proteomeglycosomes;glyoxysomes;Keywords:peroxisomes;Thisofinnarrow1. INTRODUCTIONrange species.onlybe found a veryinluciferase fireflieswerenamed microbodies, first is the case forthe fluorescentPeroxisomes,initiallyforonnotedbyRhodin(1954) as partofhis PhD thesis(Gould et al. 1987) or forseveralkeyenzymestoarewhich restricted aofmouse theproduction penicillin,tubulecellsfromofthemorphology proximalfew fungalgenera such as Pénicilliumastheirinitialcharacterization a(Kiel et al.However,kidney.in contrast,novel type of cellularorganellecame years later, 2000). Other peroxisomalpathways,suchdistribution as theß oxiableto iso- showa moredewhenChristian Duve andhisteamwerewidespreadofacidsor thesetofenzymesfrom rat liver and study their dation fattylate peroxisomesresponsiblesuchstressbiochemicalDespitedisplayingresponse.(deproperties Duve & Baudhuin1966). foroxidativeallthede Duve’s groupidentified presenceof several high levels of metabolicdiversity, peroxisomesininvolvedsetaandininvolved theproduction degradation havein common similar ofproteinsenzymesasandandhencegavethenameperoxi- theirofhydrogenbiogenesis maintenance, wellas theuseperoxidetheforSince then,peroxisomes ofsimilarsomesto theseorganelles.signals directing localizationtargetingofThe presence thesetooffrom variety otherahavebeen isolatedorganisms of proteins the organelle.evolutionthetraitsmetabolic commonthatanditsoonbecameevident thespecificsupports idea ofa singlethe exactfrom ary originfor all peroxisomes,canofalthoughsubstantiallyproperties peroxisomes differscenario still remains somewhat controversialat thelevelofa singleEventoorganspecies species.canenzymatic (de Duve 2007).ism, peroxisomes displayalternativeseveralbreakweIn recentcontentsyears, havewitnesseddependingon the specifictissue or theconsidered.conditionsenvironmentalIndeed, some throughsin peroxisomeresearch,includingtheininvolvedmechanismsofor elucidation themolecularofinfound specificgroups organismsperoxisomesasofandclassi- theformation division peroxisomes wellaswereinitiallythataretissues so divergent theyoffied as distinct organelles and are still now the finding novelclues about theirpossibleevolnames. For utionarytoreferred with alternativeorigin(van der Zand et al. 2006). Whilecommonlyouradvanced understandinghaveinspecieshar- suchfindings clearlyinstance,peroxisomes trypanosomatidofand evolution these widespreadof the functionand are thereforereactionsbour certainglycolyticthereis stilllittleinformationasknown glycosomesregarding(Michelset al. 2006), whereas organelles,acrossofandare named glyoxysomes the distribution diversity peroxisomessome plant peroxisomesoftheglyoxylate the major groupsof eukaryoticharbourIndeed,becausetheyorganisms.enzymesmainlycomesabout peroxisomesaetfungi, par- most of our knowledge(Hayashi al. 2000). In filamentouscycleinofthetoreferred as theWoronin from characterization peroxisomalofticularproteinstype peroxisome,theofofinfunctions themaintenance cellularintegrity a handful model species,including human,body,Pichiatocerevisiae,by sealingthe septalpore in response wounding rat,mouse, the yeastsSaccharomycesand YarrowiaHansenulapolymorphacan pastoris,etlipolytica,enzymes(Würtz al. 2009). Some peroxisomalthaliana.Theseand the model plant Arabidopsistwomodel organismsonlypartially of therepresentisinfiveesdiversity cureukaryoticmajorgroups which*tgabaldon(^crg.classified1)(Keelinget al. 2005) (figure and,rentlyofofOne contribution 12 to a ThemeIssue ‘Evolution organellarofwiththe notableexception yeast,theyrepresentinmetabolism unicellulareukaryotes’.765isThisjournal ( 2010 The RoyalSocietyThis content downloaded from 149.169.115.181 on Fri, 19 Sep 2014 14:04:58 PMAll use subject to JSTOR Terms and Conditions766 T. Gabaldón Review.Peroxisomeanddiversity evolutionacross the eukaryotictreeof lifeis represented.The level of inforFigure 1. Our stateof knowledgeon peroxisomediversitymationofperoxisomes based on literatureissearchesforeach taxa and theirmajorrepresentatives.Circlesnextto thedifferenttaxa indicatethe typeof information is availableon peroxisomes.Red circlesindicatesthatforthisgroup,extensivethatbiochemical data as well as comprehensiveproteomicsand bioinformaticssurveysare available. Orange circles indicate anintermediatelevel of information peroxisomalcomposition,mostlybased on biochemical studies of individualproteinsonor pathwayscoupled withcomprehensivesequence analysesto predictperoxisomallocalization.Yellow circlesindicatethatthe presenceof peroxisomesin thatgroup is well establishedbut thatthe level of the characterization theirfunctionofandwithinthis group is veryscarce. White circlesindicate that the presence of peroxisomeshas been studied in thisdiversityangroup revealing apparentabsence of these organdíes in all the membersstudied (only a white circle is associated withthe group) or in some of them (circleswithdifferentcolours are associated withthe group). Absence of a circlenextto thecontentin this group remainsto be clearlygroup indicatesthatthe presenceor absence of peroxisomesor theirenzymaticestablished.(Adapted froma modifiedversionof fig. 1 of Keeling et al (2005).)thecomplex multicellularorganisms.Only recently,interest has partially shifted to peroxisomes inmicrobialeukaryotes.Consideringtheiradaptationtoa variety niches and life styles,it is among theseofinorganisms,where the highest diversity terms ofmetabolic properties of peroxisomes is expected.Thanks to the availability completelysequencedofgenomes for a growingnumber of microbial eukartoyotes,we are now just starting unveil the existingofdiversity peroxisomesin these organisms.In thisreview, willprovidean overview the curIofrent state of our knowledgeon peroxisomediversityand evolution. For this, I will firstfocus on thecommon mechanisms shared by all peroxisomestothen surveywhat is knownto be specificin the majorof eukaryotictaxa. When discussing thisgroupingsmetabolic diversity,and to provide a logical framework, I will follow the classificationof eukaryotictaxa intofivemajorgroups,namelyUnikonts,Plantae,and Rhizaria,as describedExcavates,ChromalveolatesPhil. Trans. Soc. B (2010)R.This content downloaded from 149.169.115.181 on Fri, 19 Sep 2014 14:04:58 PMAll use subject to JSTOR Terms and ConditionsReview.Peroxisomeanddiversity evolution T. Gabaldón 767The2.viewandwhichthe(full-lineboxes),Figure A schematic oftheperoxisome. biogenesis maintenanceprocessescompriseinininvolved proteinandareofThecontent theofdivision, present alltypes peroxisomes. enzymaticimport organelleproteinswithdifferentsetsinvariable,(dashed-lineboxes)is highlyenzymatic beingpresent differentperoxisomespecies.Enzymesinvolved fatty metabolism reactiveinacidandareOtheradditional(inoxygenspeciesdetoxification widespread.pathwaysbetoofTheatsidesomeimportantblue)might restricted certaingroups eukaryotes. text theright-hand ofthefigureprovidesaboutthediversity evolution eachdepictedandofremarksprocess.by Keeling et al. (2005). Finally,I will discuss ourofunderstanding how the peroxisomalproteomehasbeen shaped duringevolutionand the currentdebateson the possible evolutionaryof this intriguingoriginorganelle.Throughoutthe text,an emphasis will beput on microbialeukaryotes.2. DIVERSE BUT ALL THE SAME: COMMONTRAITS OF PEROXISOMESA generalofthatdescription peroxisomes would fitmostorganisms be thatof a singlemembranewillwithfairlyconservedforboundedorganellesystemsand maintenance witha highlybuttheirbiogenesiscontentvariable2).enzymatic(figure The peroxisoinvolved fattyinmal lumenoftenharboursenzymesofand the detoxification reactiveacid metabolismInaofanaoxygenspecies. addition, multitude otherinhavebeen observedbolic and catabolicprocessesorcertaintaxa. In contrast mitochondria chlorotodoplasts,peroxisomes not possess an organellarAll peroxisomalproteins are thereforegenome.inandencoded thenuclearbygenome translated cytosolic ribosomes.These proteinsmust then beintobyimportincorporated the organelle specificofwhich on thepresence targetingroutes,signalsrelyin theirsequences(Brown& Baker2008; Girzalskyofetal. 2009; Ma & Subramani2009). The majorityusematrixproteins a shortperoxisomalperoxisomalwhichsignal (PTS) at theirC-terminus,targetingaminoacidsSKL or conofconsists thethreemainlyresiduessituatedvariantsservativethereof,althoughonseemto havean influence thetransportupstream&however,(Brocard Hartig2006). Otherproteins,use thealternativePTS2 with conthebi-partitesignalsensussequence [RK]-[LVI]-x5-[HQ]-[LA]at theirInN-terminalsomeperoxisomalregion. addition,proteins notpossessa recognizabledoandtargetingsignalaretransported peroxisomesintoassociatedwithotherdomains Pex5 or withofotherPTS-carryingproteins(van der Klei & Veenhuis2006a). Targetingsignalsare recognized a molecularthatbymachinery carriesThisintomatrix.peroxisomalproteins theorganellartoimport complex,referred as the importomerof(Agneet al. 2003), consists two mainfunctional/structuralmodules: a membraneproteincomplexthePexl3 andincluding receptordockingproteinsPexl4 and a receptormodule on the cytoexportplasmic side containing several RING-domainproteins,ubiquitinatingenzymes and the AAAATPases Pexl and Pex6 (Grou et al. 2009). Thisissuchas Pex5 andsystem used byreceptorproteinsinPex7, whichshuttle and out of the peroxisome,theirtherebycargoesintotheperoxisomalimportingmachinmatrix.theimportImportantly, peroxisomalhas no resemblance thoseof otherorgandíestoeryandsuch as mitochondria chloroplasts, presentsandablefoldedtheofproteinsparticularitybeing totransportet(McNew &(Walton al. 1995) and evenoligomersofGoodman1994). Despitethepresence a commonininvolved theimport peroxisomalofset ofproteinsinthis systemparticularitiesproteins,may presentFor instance,thethe differenttaxonomicgroups.a5.possesses setofbiogenesisproteinsyeast cerevisiaebeenfoundinofwhichfor13 havenotyethomologueset(Schlüter al. 2006), althoughplantsor mammalsamongfungi(Kiel et al. 2006).theyare conservedthatseemsto be sharedby allAnothermechanismPhil Trans. Soc. B (2010)R.This content downloaded from 149.169.115.181 on Fri, 19 Sep 2014 14:04:58 PMAll use subject to JSTOR Terms and Conditions768 T. Gabaldón Review,Peroxisomeanddiversity evolution3.viewshowsFigure A schematic ofmammalian(a)cell,peroxisomes. Micrographpartofa ratliver where(P),peroxisomescan be seensurrounded othercellularsuchreticulum andbycompartments as thenucleus(N), therough(ER)endoplasmicmitochondrialatticeformedinsideperoxisomes,whichresultsfrombound enzymatic(M). Note the crystallinetightlymaterial.Pictureofofthekindlyprovided DouglasF. Brayby(University Lethbridge). A reconstruction peroxisomal(¿>)proteome metabolism inferred proteomics is shown.andasfromdataColourcodesindicate likelytheofevolutionaryorigins theasandproteins follows:red,green,alphaproteobacterial;blue,yellow,eukaryotic; actinomycetales; cyanobacterial; white,undetermined.from modifiedaversion fig.5 ofGabaldónetal. (2006).)of(Adaptedisfortypesofperoxisomes thatresponsible thedivisionof the organelle.In recentyears,therehas been a significantinprogress the elucidationof thismechanism,whichhas been shownto be largelyconservedin yeast,and mammalian peroxisomes. This divisionplantmachineryinvolves,at least, a dynamin-likeproteinand a TPR (Tetratrico tide Repeat)-motifcontainPeping protein that serves as a membrane anchor.these proteinsare also involvedin mitoInterestingly,chondrial fission,establishinga link between theseorgandíes (Delille et al. 2009).In terms metabolism, picture ratheroftheisdifferentand extremely levelsofdiversity be foundacrosscanhighdifferenttaxa. Althoughmost peroxisomesshare thepresence of some fattyacid oxidation routes, etherandforoflipidbiosynthesis enzymes the detoxificationreactiveoxygenspecies,thereseems to be no commonset of enzymesthatcorrelateswiththeprescompletelyence of peroxisomes,that is, enzymespresentin allspecies with peroxisomesbut absent fromorganismsdevoidoftheorganelle(T. Gabaldón & B. Gasse 2009,unpublisheddata). This view of the peroxisomeas anwithfairlyconservedorganellebiogenesisand maintenance mechanisms witha largelybutvariableenzymaticcontentshaped to the specificneeds of each organismor tissueis likely become moreestablished peroxitoassomes fromnovel organismsare characterized. theInIoverview theofsections, willprovidea brieffollowingmain metabolic characteristics peroxisomesfromofthemajoreukaryoticgroups.3. PEROXISOMES IN UNIKONTSUnikonts constitutea recentlyproposed taxonomicgroup that includes amoebozoans, metazoans andfungi (Cavalier-Smith 2002). Without any doubt,thisgroup is the one forwhichwe knowmore detailsabout its peroxisomes. Peroxisomes of metazoanssuch as human, mouse or rat have been extensivelycharacterized(Schlüteretal. 2007). For instance,proteomicanalysesof ratliverperoxisomeshave reportedmore than 50 peroxisomal proteins (Kikuchi et al.2004; Islingeret al. 2006). A wide rangeof enzymaticfunctionshave been identified mammalianperoxiinsomes includinga oxidation of branched chain fattyacids, amino acid metabolismand differentsteps forthe synthesisof purines, pyrimidines,cholesterol,etherlipids and bile acids (figure3). Comparisonsoftissues such as mouseperoxisomes from differentliverand kidney(Mi et al. 2007) have pointed to theexistenceof tissue-specificspecializations.Severalmicrobialeukaryotesbelong to the Unikontunicellularfungiand amoebozoansgroup, includingsuch as the slime mould Dictyosteliumdiscoideum,whereperoxisomeshave been identified microscopybyand biochemicalassays (Parish 1975). However,information regarding the enzymatic content ofamoebozoan peroxisomes is very scarce. Differentstudies on D. discoideumperoxisomeshave identifiedcitrate synthase, catalase, the multi-functionalacid ß oxidation and the purineenzyme of the fattymetabolism enzymes phosphodiesterase and urateoxidase (Hayashi & Suga 1978).In contrastto amoebozoan peroxisomes,those ofhavebeen intensivelystudied.Indeed,peroxisomefungiresearch takengreatadvantageofthewealthofmolhaseculartools and genomicresources themodel yeastfor5. cerevisiae.For instance, several comprehensivestudies including the analysis of gene expressioninduced by growth in oleate (Smith et al. 2002),large-scale fluorescencemicroscopyof GFP (GreenFluorescentProtein)-fusedproteins(Huh et al. 2003)Phil. Trans. Soc. B (2010)R.This content downloaded from 149.169.115.181 on Fri, 19 Sep 2014 14:04:58 PMAll use subject to JSTOR Terms and ConditionsReview.PeroxisomeandT.diversity evolution Gabaldón 7694.cerevisiaeandas inferred proteomics Colourfromdata.codes inasFigure Saccharomyces peroxisomalproteome metabolism3.fromversion fig. ofGabaldón al. (2006).)of 5etfigure (Adapted a modifiedor subcellularofhaveproteomics highlypureperoxisomal as in othereukaryoticgroups,peroxisomes beenfractionset al. 2001; Yi et al. 2002) are lostfromsomefungalsuchas thosebelonging(Schaferspeciestheofapproaching fullcharacterization the protein to theMicrosporidia.ofinrepertoirethisorganelle.Enzymespresent theperoxisomes S. cerevisiae mainlyofareininvolved fattyacidaminoacid metabolism thedetoxifica- 4. PEROXISOMES IN PLANTAEandoxidation,tion of reactiveofPlantae characterized theareoxygenspecies derivedfromthese Members thegroupbyreactionsofderived primary4).(figure Otheryeastspeciesmaydisplay presence plastidsbyendosymbiosis.inmetabolicthisquitea differentrepertoire theirperoxi- Besideshigherplants(Viridiplantae), groupalsointhesebeingspecialized the metabolismsof includesmicrobialsuchsomes,photosyntheticeukaryotes asunusualcarbonand organicseveralsources glaucophytes,and redalgae.Peroxisomesnitrogengreenalgaeusedforstudied higherinwhere(van20066).For havebeen extensivelygrowth derKlei & Veenhuisplants,boi- theyrolesin manyinstance,methylotrophic species Candidayeast(e.gplayimportantprocessesincludingH.Pinduceperoxisome seed germination, senescence,leaffruitdiniiy polymorpha, pastoris)maturation,onastodevelopmentduringgrowth methanol a sole response abioticand bioticstress,photomorphocarbonsource.These peroxisomesharbourenzymes genesis, photorespiration,biosynthesisof plantformetabolism as alcoholsuchoxi- hormones cell signalling reactiveandandnecessary methanolbyoxygendase and dihydroxyacetonewhich may nitrogennotassynthase,species.Although as extensively inaccount up to 70 per centof theproteinforcontent mammals yeasts,andstudieshavebeenperproteomicin the cell. In filamentousformed plantperoxisomesonetfungi,peroxisomesmay(Reumann al. 2007;inalsobe involved a number biosynthetic For Eubel etal. 2008; Palmaetal. 2009). These,togetherofroles.areinstance,peroxisomes theplace forthefinalsteps with computationalanalysesof proteinsequencesof the synthesis the antibioticpenicillinin (Reumannet al. 2004), have helped to identifyofaP chrysogenum der Klei & Veenhuis20066). widevariety biochemicalofin(vanpathwayspresent perOtherfilamentouscrassa oxisomes. Among many other pathways,plantfungisuch as Neurosporainduce a special type of peroxisome,have been shownto containenzymesglyoxysomes, peroxisomesonininvolved thepentoseoxidationduringgrowth ethanolor acetate (Kionka &phosphatepathway,inKunau 1985). Similar glyoxisomes plants,tothese of fattyacids, ascorbate-glutathionecycle,biosynare characterized theirenrichmentin thesisof jasmonicacid and auxin, metabolismoforgandíesbyfromthe glyoxylateoxideand reactivePlantperoxicycle such as malate nitricenzymesoxygenspecies.and isocitrateofandMoreover,synthase.synthaseperoxi- somesshowa highdegree tissuespecializationlack the enzymecatalase.Finally, at leastfoursomesin N. crassadistinctofhavebeentypes thisorganellePhil. Trans. Soc. B (2010)R.This content downloaded from 149.169.115.181 on Fri, 19 Sep 2014 14:04:58 PMAll use subject to JSTOR Terms and Conditions770T. Gabaldón Review.Peroxisomeanddiversity evolutiondescribed.Undifferentiated peroxisomescontain groups(e.g. apicomplexans ciliates).Thankstoandplantcatalase uricase.andareofmainlyGlyoxysomes enriched the availability severalgenomicsequencesfromwithofacidandwetoenzymes thefatty oxidation theglyox- thiseukaryoticgroup, are now starting haveaand theircombinedactionallowsthese glimpse thediversity peroxisomalofofofmetabolismylatecycle,to convertthe seed storagelipids into theseForinstance, silicoinofbiogenorgandíesspecies.analysesforandsugar,necessary seedgermination subsequent esis markershave identifiedapicomplexans(e.g.Leaf peroxisomes,inaswhichlacksgrowth.present photosynthetic Plasmodium) thefirsteukaryoticgroupareinofinofmitochondriatissues, specialized themetabolism glycolate peroxisomes thepresence classicaland host many of the enzymes necessaryfor (Schlüter al. 2006). Otherchromalveolates asetsuchanotherofofandphotorespiration.Finally,type peroxisomes theciliates thegeneraTetrahymena Parameciuminhasbeenidentified therootnodules certainofettropi- do possessthisorganelle(Müller 1973; Stelly al.incal legumes, whichthe synthesis allantoinofishave1975). In oomycetes,peroxisomes beendetectedcarriedout.in the genusPhytophthoraet(Philippi al. 1975) andIn contrast therelatively amount infor- havebeenpredicted be present thediatomThatooftoinlargemationavailablefor higherplants,littleis known lassiosira pseudonana (Armbrust et al. 2004).aboutthediversity functions peroxisomes uni- However, presence peroxisomes otherofofintheofinchrocellularThe presence peroxisomes been malveolatesremainsto be established.Genomicofhasplants.insearchesfor core peroxisomalinreported severalgreenand red algae (Codd et al.proteins availableettheirdoadistribution peroxiof1972; Shinozaki al. 2009). However,specific sequences suggest patchymetabolicremainstorepertoirelargely be described. somes in severalof these groups(T. Gabaldón &B. Gasse 2009, unpublisheddata).5. PEROXISOMES IN EXCAVATESExcavates the majorassemblage protists.areofThe7. PEROXISOMES IN RHIZARIAincludes broadaofisforgroupdiversityfree-living,symbiotic Rhizaria theonlymajoreukaryoticsupergrouporparasiticwhichoften classicallackmitochon- whichno completehas yetbeenforms,genomesequencedria(see paperby Embley al. 2010). Some of the obtained. is as wellone ofthemostrecentlyetItcreatedfrom group,thissuchas theparasiticandspeciesprotozoan groupings,Cercozoa, foraminiferacomprisingGiardiaarealsolamblia^ apparently devoidof peroxi- radiolarians(Cavalier-Smith2002). Studiesreferringsomes (de Souza et al. 2004). Otherssuch as the toperoxisomesrhizarians veryinarescarce.Peroxisomesdoderivedtype of havebeendescribed solitaryasinforkinetoplastids possess a highlyorganelles severalreferred as glycosomesto&aminiferanthosethatinhabittheperoxisome(Opperdoesspecies,includingBorst1977). This groupof flagellatecom- chemocline marineofsediments&protozoa(Bernhard Bowserhuman pathogenssuch as the 2008). In such anoxic environments,Foraminiferaprises importantofand species mightbe associatedwithsulphur-oxidizingtrypanosomatids the genera Trypanosomawhichhaverecentlyreceivedconsiderable microbialwheremicromolarlevelsofH2O2 areLeishmania^mats,attention. peroxisomes theseorganismsTheofhave observed.offoraminiInterestingly,peroxisomes thesetheparticularitygenerallyofcatalaseand har- feraspecieshavebeen proposed participate thetoinlackingaofIndown of environmentalbouring number glycolyticenzymes. addition, breakinghydrogenperoxidetheseorgandíesadditionalfrom to produce oxygen,whichwould be subsequentlymaycontainenzymesa variety processesofsuch as ß oxidation fatty used in aerobic pathways(Bernhard& Bowserofthesal- 2008). Such a model…