Downloaded By: [University of British Columbia] At: 18:58 7 June 2007 ulse nclaoainwt h nvriyo egnadteIsiueo aieRsac,Nra,adteMrn ilgclLaboratory, Biological Marine the and Norway, Research, Marine of Institute the and Bergen of Denmark University Copenhagen, the of University with collaboration [email protected] in E-mail: Published Canada. 1Z4, V6T BC, Vancouver, agassizii Á archigregarine the of Ultrastructure ARTICLE ORIGINAL Research Biology Marine O:10.1080/17451000600724395 online DOI: 1745-1019 print/ISSN 2006) 1745-1000 July ISSN 24 Printed 2006; March 29 (Accepted Leander, These B. literature. Correspondence: gregarine into the develop in synonymous which ‘‘sporocyst’’ and are ‘‘oocyst’’ stage), that (Note oocysts. diploid Gametes robust zygotes mitosis. fleeting form to of fuse (the gamonts rounds different from multiple derived are the gametes by (i.e. of formed A hundreds pairings which reproduction. these within sexual ‘‘gamonts’’) around ‘‘syzygy’’, of forms as onset known gametocyst the up process pair a marks and in which host another animal one the with within extra- spaces inhabit haploid that cellular ‘‘trophozoites’’, the the large cells, general, relatively feeding of consists in archigregarines of gregarines lifecycle poly- a Like especially in invertebrates, systems chaetes. marine intestinal of of range parasitic wide apicom- are of that group plexans ill-defined an are Archigregarines Introduction of cisterna one contained that by pores reticulum. surrounded of endoplasmic and arrangement and of words: linear proper bodies reminiscent Key a dense nucleus misleadingly ridge, of transverse were the network a that a to of organelles and consisted connected membrane-bound structures the apparatus were thread-like four attachment to inconclusive, of novel blebs rise impression distinct The gave Although nuclear and the apicoplasts. that a convoluted motility. The giving highly suggested formed was reticulum, cellular sizes. profiles nucleus endoplasmic mitochondrial microtubules The different the larger trophozoites. electron subpellicular the of between behind surround connections transmission of blebs might mechanism narrow reticulum and clusters and association mitochondrial the expansive profiles intimate longitudinal scanning an explain mitochondria-like An and small and deformations. helped and of mitochondria cellular behaviour videography presence that dynamic The of group. digital of configuration layer the capable using functional within superficial and parasitism flat described a of extremely evolution were between were early trophozoites trophozoites the The to the microscopy. on light of shed ultrastructure could and radiation apicomplexan agassizii Phascolosoma vivax Selenidium Abstract Botany, and Canada Zoology 1Z4, of V6T Departments BC, Biology, Vancouver, Evolutionary Columbia, in British Program of Research, University Advanced for Institute Canadian LEANDER S. BRIAN yai aaieo iucldwrs(host: worms sipunculid of parasite dynamic A pcmlx,acirgrn,eouin aaie eeiim iucld ultrastructure sipunculid, Selenidium, parasite, evolution, archigregarine, Apicomplexa, ) salreaduuuluiellrprst htihbt h netnllmno h otdpau worm, peanut dotted the of lumen intestinal the inhabits that parasite unicellular unusual and large a is oeua hlgne ugs htti rhgeaielnaedvre ertenxso the of nexus the near diverges lineage archigregarine this that suggest phylogenies Molecular . 06 :178 2: 2006; , # 5967 nvriyBv,Dprmnso oayadZooy nvriyo rts Columbia, British of University Zoology, and Botany of Departments Blvd, University 3529-6270 Á # 190 06Tyo Francis & Taylor 2006 eeiimvivax Selenidium eg ‘eooy’(eie17) hc sthe is which 1971), un- archigregarines (Levine It some ‘‘merogony’’ epithelium. that dergo intestinal suggested host been the has infect same and the excyst in living be hosts to other only environment. by become environment and ingested the faeces orally in the distributed with host widely infected an leave and (e.g. and archigregarines sporo- of eugregarines case more the intestinal produce In oocyst. can per mitosis archigregarines zoites of some rounds in tional reported (Grasse been 16 also to six have sporozoites. from oocyst ranging banana-shaped numbers sporozoite each However, four within produces Meiosis usually the in literature.) meanings different coccidian very have however, terms, neigse ytenwhs,tesporozoites the host, new the by ingested Once Gregarina 93 eie17) negeaie,addi- eugregarines, In 1971). Levine 1953; ´ ,teocss i h gametocysts, the via oocysts, the ), Phascolosoma (Apicomplexa) Lecudina , Lankesteria Downloaded By: [University of British Columbia] At: 18:58 7 June 2007 e od (e.g. Chao cell relatively folds has the & 2002; trophozoites few eugregarines, archigregarine Cavalier-Smith al. in of surface et 2003b; unlike Moreover, Kuvardina al. 2004). 1996; et apicomplexans, Patterson Leander Simp- parasitic & 2000; 1991, the son free- (Mylnikov nearest of colpodellids the namely in relatives present also living is feeding (Schre of cytoplasmic vacuole) mode the food withdraws a and into cell contents a host of or wall & (the the cell pierces myzocytosis prey cell Kuvardina by predatory a feeding use whereby 1994; for process to complex 1993, appear apical trophozoites the al. The 2002). et Simdyanov Schre 1930; Dyson (Ray 1970; complex (Schre and apical movements spin- an size undulating often have of are in capable stages both dle-shaped, differ instance, often For but are 1971a,b). archigregarines similar they in remarkably which stages extracellu- trophozoite from and lar sporozoite sporozoites intracellular significantly the the are develop, tropho- from behaviour where and different eugregarines, morphology in Unlike zoite whole. Apicomplexa a the for as because plesiomorphic features be several probably to retained appear have identified, that group be the of to members yet has garines 2002). Simdyanov & field Kuvardina the 1986; Small in & workers other with (Schre consistent to is refer which instead and of scheme to members not taxonomic chosen this have I follow ‘‘demon- difficult, is and absence’’ straightforward an strating not is merogony ving (e.g. genera versus cohesive highly otherwise archigregar- the from them ines exclude to species used most tro- been in has or merogony of sporozoites absence The either phozoites. of multiplication asexual pcmlxn aeeovd(Grasse other all evolved which have the have from The authors form group several apicomplexans might stem reasons, archigregarines paraphyletic above that the speculated For of coccidians, host. single many a all within and lifecycle gregarines their hosts, complete other invertebrate they all their like of tracts and intestinal environments the marine and to confined also are gregarines ob ihydrvdaogidpnetevolutionary independent along derived highly be to Cavalier- 2006; 2003a, 2004). this Chao al. with & Smith et consistent al. been (Leander far et inference so phyloge- Leander have molecular analyses 2003; netic inconclusive, Keeling Although & 2006). Leander 1994; nuabgossnpmrh o h archigre- the for synapomorphy unambiguous An oehls,mn rhgeaieseisappear species archigregarine many Nonetheless, ´odoride es stricto sensu vl17ab The 1971a,b; ´vel Selenidioides s18;Vve epre 90 Cox 1990; Desportes & Vivier 1984; `s Selenidium B n a eutdi h irpinof disruption the in resulted has and / 0lniuia titos.Archi- striations). longitudinal 60 Lvn 91.Bcueobser- Because 1971). (Levine ) ´odoride sarchigregarines as s18;Gunderson 1984; `s vl16) This 1968). ´vel Selenidium vl1968, ´vel es lato sensu 1953; ´ ´vel , netnltat ftesipunculid the of the agassizii the characterizing tracts inhabits that by intestinal archigregarine we an example Here of such ultrastructure 2003a). al. one et present Leander 2002; Simdyanov Schre 1930; (Ray trajectories ot niiul ftesipunculid (0.2 the of agassizii individuals Forty organisms of Collection methods and Material (TEM). micro- scopy electron its transmission examine and digital SEM features further videography, real-time to using me morphological characteristics led ultrastructural species, unusual this in highly found combined the of data, nexus These with the radiation. near apicomplexan branches the that Molecular lineage 2003a). divergent a al. that demonstrated et analyses phylogenetic (Leander was marker subunit small species rRNA (SEM) the using microscopy phylogenetics this molecular electron and Subsequently, scanning with 1986). (Gunderson studied time Small that at micrographs presented & no were but kind 1986, any in of described first was ine heddhl faSinxfle odr containing holder, the filter Swinnex into a5 a directly Indivi- of hole seawater. deposited threaded filtered were in trophozoites twice dual washed micromanipula- by and material tion removed gut remaining were the parasites from 20 fine-tipped Approximately with sipunculids forceps. the teasing of intestine by the seawater apart into released were Trophozoites SEM camera. Axiovert Mega- and colour PixeLink Zeiss pixel a to movies a connected microscope with Digital inverted produced slide. were individual trophozoites of specimen images contrast glass interference differential placed a and Leica seawater on filtered a with washed tropho- and were zoites Micropipetted stereomicroscope microscope. MZ6 inverted DMIL Leica a micromanipulated with and observed were Trophozoites microscopy Light 1986) (Gun- Small worms & different derson five of the intestines convoluted to exactly of description conformed species Marine that June Trophozoites in Bamfield Canada 2003. the Island, Vancouver near Centre, Inlet Sciences Grappler of pools Á m . bv h enlwtd)fo h rocky the from tide) low mean the above m 0.3 oyabnt ebaefle (Coring filter membrane polycarbonate m namely , eesen 97wr olce tlwtide low at collected were 1967 Keferstein, lrsrcueof Ultrastructure eeiimvivax Selenidium .vivax S. . vl17;Kvria& Kuvardina 1970; ´vel eeiimvvx179 vivax Selenidium eeioae rmthe from isolated were hsarchigregar- This . Phascolosoma Phascolosoma .vivax S. is Downloaded By: [University of British Columbia] At: 18:58 7 June 2007 aaie ihOsO with parasites tao,iflrtdwt acetone of series with graded a infiltrated through ethanol, dehydrated were Cells imtrad5c al n auae ih4% cm with (4 saturated beaker and a tall) of cm base OsO 5 inside and cm the (2 diameter was canister paper on filter small Whatman a mounted tall). cm within 3.5 seawater and diameter of ml 10 submerged USA) in MA, Acton, Division, Separations 0mni itrdsaae.Tohzie were Trophozoites OsO (w/v) seawater. 1% post-fixation before in seawater filtered filtered 4 in twice in was at washed parasites glutaraldehyde min slow (v/v) of 30 and 2% pellet with micropipetting small pre-fixed by The tube centrifugation. Eppendorf in an concentrated were trophozoites 25 Approximately TEM 6.0 Photoshop USA). CA, Adobe Jose, San Systems, using on (Adobe illustrated backgrounds and three cell same of black SEM the montages of Some images from SEM. and individual created S4700 gold, were Hitachi with micrographs a coated under sputter viewed stubs, on mounted iain i rp f4 OsO 4% of drops six fixation, pr ctn,31 :,13 uersn n em- at and polymerized was resin) block pure The 60 resin. 1:3, pure in 1:1, bedded 3:1, acetone, (pure n rtclpitdidwt CO with dried alcohol critical-point ethyl of series and trophozoites graded a The with dehydrated fixative. canister were the and from seawater removed containing was and 30% apparatus holder with filter entire filled Swinnex an the the syringe for to ml screwed fixed was 10 were ethanol A parasites min. the 30 and additional seawater the to lrctUtairtm.Ti etos(70 sections Thin 85 UltraMicrotome. Ultracut 180 oee,wsnvrsai.Ec rpoot was trophozoite 1D (Figure Each itself on static. folding of capable never and was the tape-like 2 however, of and as shape width described general 120 best approximately The is 1). defor- trophozoites cellular (Figure extreme of mations capable of and active trophozoites highly extracellular The motility and shape Cell H7600 Results Hitachi a under viewed and TEM. citrate lead ) hsbhvori ehp etdsrbdas described best of reminiscent perhaps cell is it is because different movement’’ 1H ‘‘metaboloid behaviour (Figure contract This another one T). and of independently stretch regions twist, could 8 m n etoe ihadaodkieo Leica a on knife diamond a with sectioned and C )wr otsandwt rnlaeaeand acetate uranyl with post-stained were m) 4 lcn h ekroe h aitrfxdthe fixed canister the over beaker the Placing . .S Leander S. B. Á 15 4 m 4 Á o 0mna omtemperature. room at min 30 for ndph h elshape, cell The depth. in m 500 aor.Atr3 i fvapour of min 30 After vapours. m nlnt,15 length, in m 4 eeadddirectly added were Á 2 .vivax S. ei mixtures resin itr were Filters . Á ,T G, Á 80 Á )and Z) 8 m for C min were Á Á utpemmrn-on rael Fgrs4A 5A (Figures F, organelle membrane-bound multiple otspriilrgoso h yols (Figure cytoplasm the of 4A regions superficial most n ol emr one ncnrce tropho- contracted in 2A 1, rounded trophozoites multi- (Figures more zoites extended and be relatively could in S) and point N, tapered blunt end a posterior 1G, to The W). (Figure 1V, (Figure pointed digitated C), O, I, 2A, of 1H, range (Figures wide edge-like a including had morphologies, the and of plastic also end was anterior trophozoites The euglenids. some in metaboly h rpootsof trophozoites The rssi h aea agno h elwere body 2A the cell (Figure of archigregarines the reminiscent other most were of of in that folds striations surface margin cell longitudinal the lateral transient with the associated in Crests cytoskeleton and surface Cell B). 2A, (Figure cell the of end end posterior anterior the the from to passed usually and observed elrgos(iue C ,3A D, contracted 2C, of (Figures surface regions cell the over distributed striations etostruhtecl ufc,wihcorre- on which 3G striations (Figure longitudinal surface, surface cell transient the cell the to the transverse sponded associated in through the evident Weakly to were sections microtubules 3F). perpendicular of long- (i.e. (Figure bundles cell the folds) of the along transverse bundles of oriented dense axis were itudinal by trans- that subtended the microtubules of were bases folds The the devoid verse 3I). However, was folds microtubules. (Figure transverse of the that apicomplexans of to structure other structure internal of in in comprised consistent found was was and inner pellicle layers The three or folds 3F). complex (Figure organized membrane complex of subtending and membrane series membrane inner plasma trans- a the in the were (wrinkles) that tapered striations confirmed with smooth TEM verse 3E). terminate (3) (Figure small that and ends 3D) by striations (Figure transverse basally (2) ridges supported 3C), longitudinal (Figure striations long- parallel small in transverse of aligned series ridges morpholo- transverse itudinal related (1) but including: distinct gies, three had striations auls iohnra aalcgngranules paraglycogen of consisting ( trophozoites mitochondria, cytoplasm the complex vacuoles, a through demonstrated sections Longitudinal organelles membrane-bound multiple and Mitochondria below). appa- (see attachment anterior ratus the near except observed,  / Á mlpci) og oisadsvrltpsof types several and bodies Golgi amylopectin), )adwr o bevdi h eprregions deeper the in observed not were and F) Á ) h iohnrawr oaie othe to localized were mitochondria The E). Á .vivax S. ) eitli ae eealso were waves Peristaltic D). Á ) irprswr not were Micropores J). Á lohdtransverse had also ) h transverse The E). Á D). Á Downloaded By: [University of British Columbia] At: 18:58 7 June 2007 rpoots h neiredo h eli retdt h et h rpootshdrltvl ag aelk elsae htactively that shapes cell tape-like large relatively had (bar trophozoites volume The cell left. the the expanding and to shrinking oriented folding, is twisting, cell by the conformation of in changed end anterior the trophozoites; a ude fpliua irtbls(iue 4, (Figures microtubules pellicular was longitudi- of mitochondria the bundles beneath of nal immediately layer or present dense always reticulum a large organelles. disconnected Nonetheless, a of profiles population within a constituted mitochondrial together linked independent were determined definitively the not was whether It cytoplasm. the of s frame (1 micrographs contrast interference of differential trophozoite A 1. Figure eeiimvivax Selenidium sltdfo h netnso h sipunculid, the of intestines the from isolated  1 hwn h eea elsae n ovltdwigigmvmnsof movements wriggling convoluted and shapes cell general the showing ) n h elclrmcouue otie small contained ( microtubules profiles pellicular circular profiles the mitochondrial the and between region The 5A). otie igsae nlso ossigo a of consisting inclusion ring-shaped a contained mitochondria the to 5A). structure (Figure in similar otherwise h iohnrahdtblrciteadoften and cristae tubular had mitochondria The lrsrcueof Ultrastructure hsoooaagassizii Phascolosoma  / 30 / 0.1 m m). m ndaee)ta were that diameter) in m eeiimvvx181 vivax Selenidium .(A Á B iesre of series time A BB) Downloaded By: [University of British Columbia] At: 18:58 7 June 2007 D E ftepseirtpo rpoot hwn oddcl ufc bakadwiearw)i wse ofrain(bar conformation twisted a in arrows) white and (black surface cell folded a showing trophozoite a of tip posterior the of SEM (D) cnigeeto irgah(E)o oddtohzie h neiredi retdt h etadtwrstevee (bar viewer the towards and left the to oriented is end anterior the trophozoite; folded a of (SEM) micrograph electron Scanning h ula hp hne rmcrua oood h ulou i o hnesae(roha) ogtdnlsrain ntecell the in striations Longitudinal (arrowhead). shape (bars change movements not metaboloid the nucleus, did of the co-ordination nucleolus over and passed the generation and the ovoid; images) for of the mechanism to end of underlying anterior side circular an the left-hand reflected (the to from (arrows) anteriorly end surface changed moved posterior arrowheads) the shape (double from margin nuclear moving lateral waves the the peristaltic in of crests progression As and cell. generation the the showing micrographs light contrast 182 agno h ula neoewsotnhighly often was envelope nuclear 6A the (Figure of envelope margin nuclear immediately layer the darkly vesicular inside a a nucleus and euchromatin, the nucleolus of stained homogeneous shape ultrastructure of change The consisted the not B). of 2A, did centre (Figure nucleolus the the over passed trophozoites; with contraction the The as of size ovoid to 1986). waves spherical in Small from shape & changed consistent nucleus (Gunderson was reports conspic- that a previous possessed nucleolus relatively and the 6A), uous from (Figure surfaces bulging flat trophozoites, of centre of nucleus large The Nucleus cytoplasm the within shown). not deep (data observed (Figure occasionally membranes of nested 5D consisted concentrically structures common several Less 5C). organelle membrane-bound (Figure four a giving of profiles, appearance the smaller inner of the membrane against mitochondrial pressed occasionally ring-shaped was This C). inclusion 5B, (Figure membrane double of micrographs electron and Light 2. Figure Á ) ude ftoo he irtblswere microtubules three or two of Bundles E). .S Leander S. B. .vivax S. a oiindi the in positioned was eeiimvivax Selenidium Á ) The C). hwn eea rpoot hrceitc.(,B ifrnilinterference Differential B) (A, characteristics. trophozoite general showing ula lb fvrosszs(iue6B (Figure sizes various and of extensions blebs finger-like nuclear to rise giving convoluted, fdnebde n neaoaesse fendo- of system elaborate an and bodies cytoplasm accumulation dense large The a of C). contained end 7A, anterior the (Figure near ridge. openings transverse pore the of the some of from side emerged structures opposite Vermiform-shaped the the delimited pores on ridges of pores series Discontinuous linear B). edge a 7A, to width adjacent (Figure straight was entire contin- and the a cell a spanned the of of that consisted of ridge edge transverse The uous form 7A). 2C, the of (Figures end took anterior the of trophozoites configuration stable most The apparatus/mucron Attachment four of appearance (Fig- the 6C nucleus ure the gave near organelles blebs around membrane-bound reticulum nuclear endoplasmic combined of the envelope cisterna nuclear the The the with blebs. of nuclear membranes the the two surrounded including One envelope, reticulum 6D). nuclear endoplasmic (Figure stalk of thin a to cisterna by attached proper observed nucleus frequently the were blebs nuclear Á E).  Á / 50 ) The D). m   ) (C) m). / / 5 5 m m m). m). Downloaded By: [University of British Columbia] At: 18:58 7 June 2007 F yapttv ebaeadfakdo the on flanked and membrane putative a Figure in by (left side linear 7F) a one on components: unidentified flanked following thread continuous the an of consisting contained structure the also of region This cytoplasm E). 7D, (Figure reticulum plasmic iue3(Continued 3 Figure aueo hssrcuewsucer lhuhafew a Although unclear. was structure three-dimensional 7F) this The of Figure F). nature in 7D, of (left (Figure row thread side the opposite linear of was the a granules on small by evident seven also 7F) of cluster Figure A granules. in small (right side other ) lrsrcueof Ultrastructure eeiimvvx183 vivax Selenidium Downloaded By: [University of British Columbia] At: 18:58 7 June 2007 ntases iw h ovltdpam ebae(obearwed) neliginrmmrn ope n subtending and complex membrane inner underlying arrowheads), (double (bar membrane (arrowheads) plasma view convoluted longitudinal in the microtubules view, transverse in arwed)(bar (arrowheads) rpoot ufc n neligctseeo.(,B Eso w rpootsi otatdsae(pe)adasm-eae state semi-relaxed a and (upper) state contracted a in trophozoites (bar two surface cell of the SEMs over B) striations transverse (A, showing cytoskeleton. (lower) underlying and surface trophozoite iw(rohas (bar (arrowheads) view otelniuia titossoni G (bar (G) in shown striations longitudinal the to ftases od.Srthdrgoso h rpoot ufc persot rcnantases oso iylniuia ridges, longitudinal tiny of rows on transverse regions contracted contain in folds or transverse smooth continuous into appear develop bar ridges (C, surface parallel surface of cell trophozoite rows trophozoite the the transverse These of (arrowheads). parallel regions in Stretched arranged folds. transverse of iir16;Schre 1968; Schre & Vivier archigregarines (Vivier several eugregarines intestinal in and demonstrated vesicles’’) been ‘‘pinocytotic (so-called have struc- function same pro- the and vesicles with ture Vesicles nutrient-carrying endocytosis. by are duced E) multiple 5D, cytoplasm the is (Figure the of in found some It structures that membrane-bound nutrition. nonetheless likely surface-mediated highly for mechanism in surface cell 1994). (Schre 1993, al. myzocytosis et by nutrients within lum species tropho- many the of in zoites present in is absent is apparatus is this micronemes) trophozoites; This and complex rhoptries endocytosis. apical conoid, an (i.e. that via possibility the with trophozoites consistent of surface reasonably behaviour and be shape of of can cell the It that proglottids therefore, hosts. inferred, vertebrate individual their environments similar within the inhabit that conver- in flatworms has cestode that evolved characteristics of gently remarkably set is the adaptations to the of similar of set This lumen intestine. the the host with within interact can environment that nutrient-rich area increase surface motility of active amount and the shape cell flattened size, genus the in within known largest trophozoites the of Ormie enosre nafwohrgeaieparasites namely gregarine worms, orientale other sipunculid S. few infect a that in of observed shape been cell flattened large, The Discussion membrane inner the H). and 7G, (Figure membrane complex pierced plasma apparatus attachment the the (Figure of observed pores was The conoid some 7H). a of of bases evidence no the pores, near observed were microtubules 184 0.25 of (TEMs) micrographs electron transmission and (SEMs) Scanning 3. Figure and oee,mcooe eentosre vrthe over observed not were micropores However, .vivax S. m xshznsiphonosomae Exoschizon n stogtt aiiaeteaqiiinof acquisition the facilitate to thought is and m). rs16;Gnesn&Sal18) h size The 1986). Small & Gunderson 1965; `res .S Leander S. B. , aiiae uretutk costecell the across uptake nutrient facilitates .franciana S. .vivax S.  / 2.5  m vl17b epre 1974; Desportes 1971b; ´vel / ) H rnvreTMsoigdsic lseso irtblsi rnvreve bakt)ta correspond that (brackets) view transverse in microtubules of clusters distinct showing TEM Transverse (H) m). 0.2 hc ol ea expected an be would which , m ) J ihmgicto E hwn agnilve fcutrdmcouue arwed)(bar (arrowheads) microtubules clustered of view tangential a showing TEM High-magnification (J) m). .vivax S. ,  .stellatum S. / 2.5 Hki13;Tzt& Tuzet 1939; (Hukui Selenidium Selenidium m ;D ,bars E, D, m; vl16;Dyson 1968; ´vel oee,i the is however, , .vivax S.  / 0.5 , and h large The . .cantoui S. .folium S. vl1964; ´vel m  ) I ihmgicto E hwn h lsee irtblsi transverse in microtubules clustered the showing TEM High-magnification (I) m).  a also has / 0.5 / Digya- 2 m ) F ogtdnlTMtruhatohziesoigtetases folds transverse the showing trophozoite a through TEM Longitudinal (F) m). m  ) G E hwn ogtdnlsrain ntetohziesurface trophozoite the on striations longitudinal showing SEM (G) m). / 20 , m ) (C m). eet h ne ebaecmlxapa obe to appear complex microtubules membrane longitudinal inner B). of the 2A, beneath 1, bundles (Figures cell parallel posterior the of the The end from anterior the passed to usually end co-ordi- that generating waves and nated folding, and contract- extending twisting, ing, of trophozoites. capable were the trophozoites in The observed active deformations the behind cellular mechanism underlying the reflects analysis. and further reconstructions three-dimensional require and 7D will the Figure F of in shown significance structure functional linear unidentified and structural Understand- the 2002). ing Simdyanov other & of Kuvardina trophozoites 1994; Schre the (e.g. in gregarines found marine that apparatus to attachment the similar below is cluster- bodies The dense apparatus. of attachment ing the through the of absorbed pores are of intestines. the nutrients host whether attachment the unclear of is the cells It epithelial in the to function parasites the along edge pores of row anterior linear the struc- re- from thread-like emerging the tures endoplasmic Presumably, of novel. is network ticulum, convoluted highly the od nitsia eugregarines. intestinal in (1) folds in ways: motility different active and two vivax flattening increasing least cell size, at significantly cell in large by area facilitated surface nutrition cell be surface-mediated to surface-mediated seems Therefore, with complex apical nutrition. an feed- using myzocytotic-based ing replaced have that lineages (e.g. and Overall, eugregarines eugregarines. intestinal in help nutrients motility folds vivax of gliding epicytic uptake and surface-mediated the the et Presumably, facilitate Leander 1973; 2003a). MacMillan al. 1969; Small hundreds 1968; & Warner into Vavra 1968; cortex (Vivier striations the longitudinal folding of by ratio area volume surface com- the to apical increased dramatically an have lack and plex eugregarines intestinal of Like zoites 1996). Todd & Hoshida Á h tutr ftectseeo in cytoskeleton the of structure The h tahetaprtsin apparatus attachment The )SM hwn h nerdporsini h development the in progression inferred the showing SEMs E) Gregarina n 2 elrgdt n udeso epicytic of hundreds and rigidity cell (2) and tgte ihisfatndrltvs and relatives) flattened its with (together eeiimvivax Selenidium ih ersn w independent two represent might ) hwn eea hrceitc fthe of characteristics general showing vl16;Dsne al. et Dyson 1968; ´vel Lecudina .vivax S. .vivax S. , h tropho- the , Lankesteria especially , .vivax S. S. S.  / Downloaded By: [University of British Columbia] At: 18:58 7 June 2007 anfiainTM ihtemtcodi ihihe nbaki F (bar (F) in black in highlighted mitochondria the with TEMs magnification lgla xnmsadoyoa xsye have molecu- axostyles microtubule-associated oxymonad that of and demonstrated movements bending axonemes the flagellar on for Studies necessary motility. forces the cell of production the in involved 4 of (TEMs) micrographs electron Transmission 4. Figure uefiildsrbto fmtcodi.(,B dnia o-anfiainTM ihtemtcodi ihihe nbaki B (bar (B) in black in highlighted mitochondria the with TEMs low-magnification Identical B) (A, mitochondria. of distribution superficial m ) C )Ietclmdmgicto Eswt h iohnrahglgtdi lc n()(bar (D) in black in highlighted mitochondria the with TEMs mid-magnification Identical D) (C, m). eeiimvivax Selenidium cigo elclrmcouue rajcn bun- adjacent or microtubules pellicular mechanism on dyneins, similar acting micro- a or adjacent speculative, between kinesins Although tubules. sliding as for such responsible are (MAPs), motors lar hwn h at ope yols ftohzie n the and trophozoites of cytoplasm complex vast, the showing  / 1 m m). lrsrcueof Ultrastructure  / 1 eeiimvvx185 vivax Selenidium m ) E )Ietclhigh- Identical F) (E, m).  / Downloaded By: [University of British Columbia] At: 18:58 7 June 2007 E hwn uaiepncttcvscecnitn ftrepiso ocnrcmmrns(ros i (arrows; membranes concentric of pairs three of consisting vesicle pinocytotic putative a showing TEM h qaesae tutr ihntemmrnsi rbbyafiainatfc (bar artefact fixation a probably is membranes the within structure square-shaped The nlso ihnamtcodinsoigapi finrmmrns(ro)adapi fotrmmrns(obearwed (bar arrowhead) (double membranes outer of pair a and (arrow) membranes inner of pair a showing mitochondrion a within inclusion rnls()admtcodi ihrn-hpdicuin arw)(bar (arrows) inclusions ring-shaped with mitochondria and (p) granules 186 uaiemcaimwudas as transient those cause with consistent are also that striations would longitudinal the mechanism in for putative responsible observed be deformations might cellular microtubules of dles 0.2 of profiles small and arrowheads) (double (bar cristae (arrows) tubular cytoskeleton well-formed the beneath with vesicles mitochondria mitochondria-like showing TEM of (A) (TEMs) organelles. micrographs membrane-bound electron Transmission 5. Figure m ) D E hwn uaiepncttcvscecnitn fadneacmlto fcneti ebae (bar membranes concentric of accumulation dense a of consisting vesicle pinocytotic putative a showing TEM (D) m). .S Leander S. B. .vivax S. This . eeiimvivax Selenidium  / 0.5 m ) B E hwn og oy() eils() paraglycogen (v), vesicles (g), body Golgi a showing TEM (B) m). irtbls(rmcouua ude)interdigi- bundles) microtubular the If regions. (or cell transverse contracted microtubules of of surfaces generation the the on folds explain help would ing bevdin observed hwn h lrsrcueo iohnraadohrmultiple other and mitochondria of ultrastructure the showing  / 0.5 m ) C ihmgicto E faring-shaped a of TEM High-magnification (C) m).  .vivax S. / 0.2 m m). oevr irtblrslid- microtubular Moreover, .  / ne,m inner,  / ide o middle,  / 0.5  m ) (E) m). / outer).  / Downloaded By: [University of British Columbia] At: 18:58 7 June 2007 hwn ormmrns(ro-,arw2 ro-,arw4 rudancerbe n.Teotrtommrnsaeitrrtdt be to interpreted are membranes two outer The (n). bleb nuclear a around (bar arrow-4) reticulum arrow-3, endoplasmic arrow-2, (arrow-1, membranes four showing arwed)adabe mrigfo h ulu n yacntitdsak(ro)(bar (arrow) stalk constricted a by (n) nucleus the from emerging bleb a and (arrowheads) iohnralk raels(ro)advscelk rjcin ftences()(bar (n) nucleus the of projections vesicle-like and (arrow) organelles mitochondria-like h ovltdevlp arw)(bar (arrows) envelope convoluted the iue6 rnmsineeto irgah TM)of (TEMs) micrographs electron Transmission 6. Figure hog rpoot ttelvlo h ulu n hwn h atndcl hp,tencels(o n h ug ntecl rae by created cell the in bulge the and (no) nucleolus the shape, cell flattened the showing (bar (n) (arrow) nucleus the nucleus of large level the the at trophozoite a through  /  0.25 / 4 m m ) B E fances()soigavsclrlyr(rohas oiindbnahtefigr of fingers the beneath positioned (arrowheads) layer vesicular a showing (n) nucleus a of TEM (B) m). m).  / 2 m ) C ihmgicto E hwn nolsi eiuu arwed)around (arrowheads) reticulum endoplasmic showing TEM High-magnification (C) m). eeiimvivax Selenidium hwn h lrsrcueo h ulu.()Tases TEM Transverse (A) nucleus. the of ultrastructure the showing  / lrsrcueof Ultrastructure 1 m ) D E hwn nolsi reticulum endoplasmic showing TEM (D) m).  / 0.5 m ) E ihmgicto TEM High-magnification (E) m). eeiimvvx187 vivax Selenidium Downloaded By: [University of British Columbia] At: 18:58 7 June 2007 arwed)bnahtetases ig arw)adtra-hpdsrcue mrigfo h oe dul rohas (bars arrowheads) (double pores the from emerging structures thread-shaped and (arrows) ridge transverse the beneath (arrowheads) rnls(rohas otergtadasalcutro ee ml lcrndnegaue otelf dul roha)(bars arrowhead) (double left the to granules electron-dense small electron-dense small seven of of row cluster adjacent an small with a (D) and in shown right (arrow) the thread to linear (arrowheads) unidentified the granules showing TEM High-magnification (F) itiuino nolsi eiuu arwed) eils() iohnra(ro)na h neiredo rpoots(bars trophozoites of end anterior the near (arrow) mitochondria (v), vesicles (arrowheads), reticulum endoplasmic of distribution (bars neirprs(ros n nuietfidlna tutr dul roha)(bars arrowhead) (double structure linear unidentified an and (arrows) pores anterior 188 0.25 a of consisting trophozoite a (bar (arrowheads) of 1 pores edge of anterior arrangement the linear showing a SEM and Low-magnification (arrows) (A) ridge of end). transverse (TEMs) (anterior micrographs electron apparatus transmission attachment and trophozoite (SEMs) Scanning 7. Figure m ) D o-anfiainTMo h neiredsoigcutr fdnebde arwed) nolsi eiuu (er), reticulum endoplasmic (arrowheads), bodies dense of clusters showing end anterior the of TEM Low-magnification (D) m). m  ) G )Hg-anfiainTM hwn h pnnso eea oe arw)adsbedn irtbls(arrowheads) microtubules subtending and (arrows) pores several of openings the showing TEMs High-magnification H) (G, m). / 0.1 .S Leander S. B. m m).  eeiimvivax Selenidium / 2.5 m  ) B )Hg-anfiainSM hwn pores showing SEMs High-magnification C) (B, m). / 2 m ) E ihrmgicto E hwn the showing TEM magnification Higher (E) m). hwn h eea hrceitc fthe of characteristics general the showing  / 1 m m).   / / Downloaded By: [University of British Columbia] At: 18:58 7 June 2007 o te pce of movements species bending other and undulating for proposed the been explain has to mechanism MAP-based similar those like folds, in Transverse and found compensate. (wrinkle) to complex over order fold membrane in to need inner would membrane plasma overlying length the cell the overall towards the shrink microtubules and would cell of the of sliding middle the then tate, ltl urud h rpootsin trophozoites the com- connections that surrounds reticulum narrow pletely mitochondrial suggestive expansive is of an profiles of presence mitochondrial larger the microtu- between pellicular and the bules below gregarines, immediately profiles lecudinid some The in present namely as reticulum be mitochondrial some such might a is that parasites, there suggesting and evidence related 1983), been (Paulin distantly have trypanosomatids in mitochondria reported Reticulated large disconnected a of organelles. population within a together constitute or linked reticulum are pellicu- microtubules the lar below positioned profiles mitochondrial 1980). Stebbings & Mellor 1974; al. et Stebbings a play of also dynamic motility might cell that the microtubules in however, role the stressed, of be instability also Schre also should for (see motility configuration cellular functional microtu- active highly pellicular a ATP, provides and bules mitochondria of association the intimate generators between an Therefore, activity. As MAP necessary for energy host. chemical the provide sipunculid that mitochondria intestines the the suggests within of directly possible mitochondria is cells, metabolism developed presence aerobic the highly The microtubules. in of pellicular the superficially beneath mitochondria positioned of layer dense a is that fact the by hanced 2003a). al. et Leander 1994; of 1993, species other and r ossetwt h ula lrsrcuere- ultrastructure nuclear the euchromatin uniform with and consistent nucleolus are large the and meter nros(diameter enormous be parasite. this will in organization structure sectioning and mitochondrial understand serial fully to involving required gregarines study other detailed in Schre & reported (Vivier been have identical four 5C); inclusions of small (Figure appearance organelles some the membrane-bound give within profiles inclusions mitochondrial circular Moreover, trmisucerwehrteindependent the whether unclear remains It en- is mechanism putative this of viability The h ulu ntetohzie of trophozoites the in nucleus The ´odoride  / 23 .vivax S. ynclu lankesteri Cygnicollum s18) h ml mitochondria-like small The 1986). `s Á 48 vl16;Schre 1966; ´vel m nGnesn&Sal1986), Small & Gunderson in m aebe bevdin observed been have ,  Selenidum Selenidium / 20 Á 40 .vivax S. m vl17b.Amore A 1971b). ´vel nti td;dia- study; this in m eg yo tal. et Dyson (e.g. (Schre oehls,a Nonetheless, . Dsots& (Desportes vl17b.It 1971b). ´vel vl1971b; ´vel .vivax S. .vivax S. Digyalum is . adi ,Ormie J, Baudoin References Canadian Evolu- Biology. in the Program tionary Research, and of Advanced for Council 283091-04) Institute Research Natio- (NSERC the work Engineering Canada from and B.S.L. This Science to nal grants feedback. their by for supported constructive reviewers was anonymous and two thank attentive to wish I Acknowledgements here. the reported as vesicles such pinocytotic or inclusions represent blebs cellular nuclear literature other earlier or the apicoplasts in membrane- organelles multiple determine the bound to whether difficult alone images very from is it Accordingly, 1972). Schre the (Vivier 1965; in apicoplasts unknown Hennere of & reported discovery the been to of prior have literature function organelles and homology membrane-bound four aairSihT hoE.20.Poavoaepyoeyand phylogeny Protalveolate 2004. EE. Chao T, Cavalier-Smith ovltdncerevlp n ula blebs nuclear and in envelope observed The nuclear apicomplexans. and convoluted gregarines other in ported lhuhaiolsshv o endefinitively 2005). (or been McFadden gregarines not & in Waller have demonstrated 1998; apicoplasts Lang-Un- al. Although 1997; et al. et nasch apicom- (McFadden different several lineages in plexan reported been have membranes) that four photo- by vestigial surrounded organelles (i.e. synthetic apicoplasts the of cell the reminiscent within 6C is position (Figure and morphology proper were general nucleus This the and near membrane-bound sizes four organelles of reticulum, appearance endoplasmic different the gave of which cisterna of a by were surrounded blebs Ormie nuclear & several doin in The & observed (Desportes been eugregarines have but archigregarines, epre .17.Utatutr teouinnucle evolution et Ultrastructure 1974. I. Desportes o E.19.Teeouinr xaso ftesporozoa. the of expansion evolutionary The 1994. FEG. Cox epre ,The I, Desportes epre ,The I, Desportes ’lrsrcuede l’ultrastructure pyu yoo o.nv) uoenJunlo Protistol- dinoflagellates of and Journal 40:185 Sporozoa European ogy nov.). of nom. origins Myzozoa (phylum the and systematics 5. des Se Hebdomadaires Rendus Comptes Didymophyidae. garine, fungoides trophozoı nentoa ora o aaiooy24:1301 Parasitology for Journal International oa vcclide celui avec Noyau phronimae Callynthrochlamys ora fPooolg 16:449 Protozoology of Journal gre acsd l’Acade de ´ances grn Aiopea euiia)prst e anne des parasite Lecudinidae) (Apicomplexa, ´garine ¨ e ’n gre d’une tes .Cden.Junlo rtzooy21:83 Protozoology of Journal Codreanu. M. Á 212. lrsrcueof Ultrastructure ´odoride ´odoride .vivax S. rsR 93 u ulusparticularite quelques Sur 1973. R. `res rs17;Dsots17) The 1974). Desportes 1973; `res medsSine.Prs(eisD 277:73 D) (Series Paris Sciences. des ´mie iyohe chaudefouri Didymophyes sJ 99 lrsrcued agre la de Ultrastructure 1969. J. `s hlcl salpae Thalicola sJ 1986. J. `s grn d’ephe ´garine vl17b Porchet-Hennere 1971b; ´vel r nomni marine in uncommon are rne;e Frenzel; Á 60. eeiimvvx189 vivax Selenidium ynclu lankesteri Cygnicollum ´odoride Fezl (Eugregarina). (Frenzel) ´me td compare ´tude Cryptosporidium ´ropte Ormie s16;Bau- 1969; `s `re: Á 16. rs Eugre- `res, Enterocystis ed son de ´e ar des ´aire Á ´garine .sp., n. 94. Á sde ´s ´lides E). ), Á Downloaded By: [University of British Columbia] At: 18:58 7 June 2007 uadn N ene S lsi V ynkvA,Keeling AP, Mylnikov VV, Aleshin BS, Leander ON, Kuvardina from gregarines the On 1939. T. Hukui and surface cell of structure fine The 1996. KS. Todd K, Hoshida yo ,GaaeJ vnetP.19.Temco fthe of mucron The 1993. PJ. Evennett J, Grahame J, Dyson ene S aprJ,KeigP.20a oeua phylogeny Molecular 2003a. PJ. Keeling JT, Harper BS, Leander 1998. JR. Barta J, Munholland ME, Reith N, Lang-Unnasch in syzygy of structure Fine 2002. TG. Simdyanov ON, Kuvardina 1986. EB. Small J, Gunderson of Grasse complex apical The 1994. PJ. Evennett J, Grahame J, Dyson ene S eln J 03 opotssi lelt evolu- alveolate in Morphostasis 2003. PJ. Keeling BS, Leander ene S ly A,Mrhl ,LnesS.2006. SC. Landers W, Marshall SAJ, Lloyd BS, Leander Keeling AP, Mylnikov VV, Aleshin ON, Kuvardina BS, Leander 190 aMla G 93 ofrainlcagsi h cortical the in changes Conformational 1973. and WG. MacMillan Archigregarinorida the of Taxonomy 1971. ND. Levine elrJ,SebnsH 90 irtblsadtepropagation the and Microtubules 1980. H. Stebbings JS, Mellor 1997. N. Lang-Unnasch ME, Reith RF, Waller GI, McFadden ynkvA.19.Teutatutr n ilg fsome of biology and ultrastructure The 1991. AP. Mylnikov et hyaetefe-iigacsoso apicomplexans. of ancestors free-living 49:498 Microbiology the colpodellids Eukaryotic sug- of of are genes Journal rRNA phylogeny they subunit The small gests using 2002. Alveolata) TG. (Eukaryota, Simdyanov PJ, University Hiroshima 7:1 the 1) div. of B, Science (ser. of Journal (Keferstein). 35:309 Protozoologica Acta of projections hari-like 72:107 Parasitology of Journal 1867. ferstein, sipunculid the from Apicomplexa) itr 27:557 History Littorina gregarine Protisto- taxonomiques. 22:47 implications logica et fixation de L’appareil n ufc opooyo aieaett rgrns(Api- gregarines 89:1191 aseptate marine of complexa): morphology surface and 28:1743 phylum Parasitology the 54. for of Journal parasites in International ancient Apicomplexa. and widespread are Plastids 2:169 pennatum Selendium 590 p Masson. Paris: Zoologie. Lankester, gre gregarinidea 1885; 1866; Haeckel, Gregarinae nov.; n. pha 28:1 History Natural of nal gregarine the in rnsi clg n vlto 18:395 Evolution and Ecology in Trends tion. polyche aaiim rts 157:45 Protist parasitism. (Apicomplexa) gregarines Lithocystis marine of Phylogeny Microbiology Eukaryotic 50:334 of of Journal apicomplexans. morphology of ancestry surface edax and phylogeny Colpodella Molecular 2003b. PJ. ora fPooolg 20:267 trophozoite. Protozoology gregarine of a Journal of movements peristaltic during region Protozoology 18:704 of Journal Apicomplexa). (Protozoa, Selenidiidae fbnigwvsb h archigregarine, 87:149 the Biology Experimental by of waves Journal bending of 261 p Springer. Berlin: Evolution. editor. and D, Systematics Bhattacharya Plant In: parasites. apicomplexan in Plastids ersnaie fodrSiooaia(rtza.Zoologi- 70:5 (Protozoa). Zhurnal Spiromonadida chesky order of representatives -.15.Cas e gre des Classe 1953. P-P. ´ .S Leander S. B. Á `tes Á Á 77. Á grnsdsatus.I:Grasse In: auteurs). des ´garines 40. 17. pce Mluc,Gsrpd) ora fNatural of Journal Gastropoda). (Mollusca, species iylmoweni Digyalum 205. and atoiehystrix Laetmonice Lecudina Á 60. iylmoweni Digyalum Á Lankesteria 64. Avoaa:isgt notephagotrophic the into insights (Alveolata): Á 23. Sooo,Acirgrnd) Protistology Archigregarinida). (Sporozoa, Á and 15. iioimozaki Filipodium Pooo,Aiopea,prstcin parasitic Apicomplexa), (Protozoa, Á Selenidium 60. Á Á eeiimvivax Selenidium Á 7. 15. grnmrhs(Gregarinomor- ´garinomorphes et Pooo,Aiopea.Jour- Apicomplexa). (Protozoa, n h rgns fcoelomic of origin(s) the and Á Á 690. .producta L. 74. hsoooaagassizii Phascolosoma ora fParasitology of Journal . ihnsm cumanense Siphonosoma -,eio.Traite editor. P-P, ´ Á uu 99gamonts. 1939 Hukui 61. Á particularite ; eeiimfallax Selenidium 504. .s.(Protozoa, sp. n. Á Á 10. 402. Á Pterospora sde ´s Á ´de 87. Ke- Á , . a N 90 tde nsm rtzai oyheewrs I. worms. polychaete in protozoa some on Studies 1930. HN. Ray photo- microscopie en Observations 1972. E. Porchet-Hennere flagellate carnivorous marine new The 2000. AP. Mylnikov Schre Schre the in mitochondrion single a of Conformation 1983. JJ. Paulin anrF.16.Tefiesrcueof structure fine The 1968. FD. Warner the of review a apicoplast: The 2005. GI. McFadden RF, Waller iirE 98 ’raiainutatutrl otcl ela de corticale ultrastructurale L’organization 1968. E. of Vivier microscopy electron Scanning 1969. EB. Small J, Vavra The ipo G,PtesnD.19.Utatutr n identifica- and Ultrastructure 1996. DJ. Patterson AGB, Simpson Schre Schre iirE Schre E, Vivier iirE enr .16.Utatutr e tdsve stades des Ultrastructure 1965. E. Hennere E, Vivier Margulis In: Apicomplexa. Phylum 1990. I. Desportes E, Vivier Ormie O, Tuzet tbig ,BeG,GrikP.17.Mcouue and Microtubules 1974. PR. Garlick GS, Boe H, Stebbings iirE Schre E, Vivier rgrnso h genus the of Gregarines polychete I’annedlide de parasite boa sporozoaire Sthenelais n.), sp. de gen., sporogenese (n. la sur electronique et nique 69:242 sitology 79:261 Zhurnal pontica Colpodella trophozoı d’anne parasites e eeiidee er conse gre leurs et Selenidiidae les 6:389 d’anne rpmsioesaeof stage trypomastigote gre Sooo,Egeaiia.Junlo rtzooy15:59 Protozoology of Journal Eugregarinida). (Sporozoa, eie lsi faiopea aaie.CretIse in Issues Current 7:57 parasites. Biology apicomplexan Molecular of plastid derived alveolata hollandei Selenidium alcmto.Junlo rtzooy15:230 Protozoology of Journal locomotion. la Protozoology of gregarine Journal movement. the to gregarine 16:745 contribution of its and theory Sporozoa) (Protozoa, gregarines 8. Phascolion 13:339 Life iseRsac 148:331 Research Tissue Aiopea ihadsrpinof description a flagellate with (Apicomplexa) predatory the of tion hzlssoooie.Junlo irsoi 7:391 Microscopie of Journal sporozoaires. les chez alveolata gre d’une coccidie la ,CrisJ,MloinM hpa J dtr.The editors. 549 p DJ, Bartlett. and Chapman Jones 73. M, Boston: Protoctista. Melkonian of Handbook JO, Corliss L, oeeti h archigregarine, the in movement eiwo h eu.Sseai aaiooy33:187 Parasitology Systematic genus. the of review a ´odoride vlJ 91.Osrain ilgqee lrsrcuae sur ultrastructurales et biologique Observations 1971a. J. ´vel vlJ 98 ’lrsrcued are la de L’ultrastructure 1968. J. ´vel vlJ 91.Cnrbto l’e a Contribution 1971b. J. ´vel vlJ 90 otiuinal’e a Contribution 1970. J. ´vel grnmrhs ora fPooolg 18:448 Protozoology of Journal ´garinomorphes. ´garine ldspolyche ´lides Á Á 426. sJ 94 h hlgn fteGeaii.Oii of Origin Gregarinia. the of phylogeny The 1984. J. `s 57. ¨ grn ugenre du ´garine .Junlo irsoi 5:213 Microscopie of Journal L. .Junlo irsoi 3:651 Microscopie of Journal L. e.Poitlgc 7:101 Protistologica tes. euiapellucida Lecudina Selenidium et oltoh durchoni Coelotropha vlJ 96 e lrsrcue yolsiusde cytoplasmiques ultrastructures Les 1966. J. ´vel Á vlJ 94 E 1964. J. ´vel rsR 95 u ulusGeaie aaie de parasites Gregarines quelques Sur 1965. R. `res Aspidosiphon 42. Ahoiie) rtsooia8:245 Protistologica (Aphroditides). ldspolyche ´lides Á Á dtra epniiiy glKarlsbakk Egil responsibility: Editorial 4. 6. ts .Cce ilgqe.Protistologica biologiques. Cycles I. `tes. Cloeld,Pooo) Zoologichesky Protozoa). (Colpodellida, .s.gre sp. n. , tsninte son et Á Selenidium rpnsm cruzi Trypanosoma 80. Á Spnuin) rtsooia1:43 Protistologica (Sipunculiens). ´ 45. e eprsae ’lmnainet l’alimentation avec repports ses : ue umcocp e microscope au tude, ts I lrsrcued quelques de Ultrastructure II. `tes. Selenidium qecssrl syste la sur ´quences ´re td e eeiideparasites Selenidiidae des ´tude rtsooia1:89 Protistologica . grn aaiede parasite ´garine opdlapugnax Colpodella tpu l’e pour ˆt Á eeiimfallax Selenidium aaiooy22:370 Parasitology . 30. opdlaturpis Colpodella td e Selenidiidae des ´tude aaiede parasite , go ante ´gion td el nutrition la de ´tude Á Á hnhcsi pilosa Rhynchocystis 28. 70. ora fPara- of Journal . eonasthenelais Dehornia Á 46. mtqedes ´matique rer ela de ´rieure ´lectronique, Á Cienkowski Á ´ge eland Cell . Á Á 55. 70. .s.and sp. n. Sabellaria Sabellaria 410. 104. ttf de ´tatifs Á 98. Á Á 400. 73. Á Á