ABSTRACTS

3

1A

The Palyphyleti; Sature 01 Amoebae, JEFFREY D SILBER.LlAN+, LINDA A AMARAL ZETTLER'. THOMAS A NERAD?. DAVID A. CAROX;. and MlTCNELL L S001N'. "Bs\ Paul Center !or Comonrativc Molecular B i o l o ~ v and Evolution. Marine BioIo~~~c:i l

East Coast Conference on Protistology 7th Meeting

May 21-23, 1997 (Abstracts 1-29, 189)

1 Implications uf Dinoflagellate Trophic Diversity to hdicrobial Food Web Dynamics. D.

Wayne Coats. Snirhsoniaii Environmental Research Cunter, Edgewater. MD, 21037 P l d f o n i c dinollagellates represent a diversc and frequently abundmf component of

marine and rshmne ecosystenis. Their sfructural and physiological dimrsity I S manifested in variety o f trophc behaviors that encompass phototrophy. Iieterotrophy. misotrophy. :ind parasitism. Pho:os) ntlietic dmoflagellatcs arc !niponant primary produccrs, cspecdly 1indr.r enviroimienfal conditions that promofe bloom formation. while Iieferotroplitc species :ire vicwcd JS significanl mcrobial consumen. In addition, sonic heterofrophic dinoflagcllatts l i r d on invertebrates (e f.. nauplii and ~ s g s of copepods) and may exert considerable grazing pressure o n zooplankton. R x e n f sludies have also dcinonsfrated Lhaf many pliotosynflietic dinoilagcllxrs ingest prey and. JS such. represent mixoirophic species capable at- functioning simiiltaiieuus at different trophic :cwIs. Wliile iiiixotraphic dinollagcllatcs are known 10 feed on .I tmci! , of prufisfs. inosf s p x i e s seem fo exhibit some degree of prey speciticity. Dcpcnding on the particular nature ~i h e predator-prey relationship. dinoflagellaic misotrophy may cifher incrcase or dccrcase fropkc efficiency within plnnktaiiic communities Psras1tlc dinoflapellaics infcct il

wide .issorlmcnt Jf hosts including appcndiculxia, cliariognafhs. copepods. siphoiiophurr,. and proiists Many oifhcse parasifes kill their host in order to reproduce and some can prsvcnr liost reproduction. l h s . parasitic dinaflagellafes probably play a very irnponanf role in inlcrnhial food webs. with epidemic infections lidving the potential to promote rapid decliiics 111 Ih i j t

populalions.

2 Preliminary Genomic Analysis Of The Microsporidian Parasite SDraquea

looh,r GREGORY HINKLE (1,2) AND MITCHELL L SOGIN ( 2 ) , 1 Department of Biology UniversQ of Massachusetts Dartmouth 2 Program in Comparative Molecular Biology and Evolution Marine Biological Laboratory Woods Hole Massachusetls

range of invertecrate and vertebrate hosts Microsporidia divide and grow only within other eukaryotic cells a life history that precludes direct biocbimical analyses The microsporidian parasite Spraguea lophii infects goosefish (Lophius amencanus) one of the primary catcbes of the New England fishery where they give rise to large tumors in nerve tissue T t e incidence of infection among goosefish is near 100% The effect of the infection on (joosefish growth and development however is unknown in part because our kncwledge of microsporidial biology is so scant

Microsporid'a have among the smallest known eukaryotic genomes Spraguea lophii cells wntain approximately 6 2 million base pairs a size more characteristic of bacteria We have taken advantage of this small genome size in order to indirectly describe microspondian biology and biochemistry Our approach has involved the construction of a genomic library the use of automated DNA sequencing technologies and the developrent of software tools to conduct systematic searches of molecular databases Sequence similarities of protein-coding regions have indirectly provided a wealth of here-to-fore inaccessible information on microsporidian biology

Microspordia are a phylum of amitochondrial parasitic protists that infect a broad

k&nto;y, \i:oods Hole. xl.4 025Jj. tAmerican Type C u l t u ~ ~ Collection. 12301 Parklawn Drivc, Rockiille. .\ID 20S52. :Biology Deparimeni. Woods Hole Oceanographic ln\titution. Wuods Hole. \[A 02513.

The or.$ morphologiaal character which .ill amoebae h i r c is the presence uI pwdopodia life cycle. Funher clsssical tasonomic diviiion of amoehod form5 i s pauciry of distinctive strueturd characters. Some of the inure important ficxion of amoebae include w e , ihspc. rhc mucture OS the pseudopodia. hondrial cristae, the presence of g o l y Liictyocomes. the prescncc of d

flagellate 1 1 3 0 ~ the capability oiencyatment and cyar cliar3ctcri\tcs Evcii Ziven thesc plieiieiic chnmctzrs. the LIassificntion ot the moebae i ? .\I bed conrciitioii, To addreis [hi, pioblcm. w c hequenced the l6S-like rRYLU-\ coding regions ofa number oS inarine and nun-marine amoebae to ieconstuct e\o!utionnry histon on the hasis ot inolcciildr itmiliiritics In general. our d:it~ dcmon,tmte tk.2 e\trems pohphylctic nnturz of thc iimocbae bur reveal mrtain distinct cladc\ i s 2 the Hetrroloba~sa).

A goo; example oim,classification of amoebae 15 icpremitcd by the A c m t l i ~ r c : ~ dnd the Polycysrinea. : 1 0 c13sses oimoeb.ic that iire eclus~rely planhtonic .ind occur .tiicrly in oligotrophic rnrine en\ iroiinicnts. Tlisse two cl.i~zcs are included in the rupercla>c Actiiiopoda based on ipecislized pseudopodia called 3XopOdin. Phyl ieyons do not support rhs common nncestry of the Aeon the supercl.iss +crinopoJa IS aniiicisl and should be disc monophyl) oi'he Acmhnrca and ihc separate inonvphy \equcnccr ~ b 3 i confirmed b! m lili hybridrz;lrionc

4 Of Clliatas and Zytcchalasins. ROBERT V. 7.ACKPOFB' and LINDA A. HW€NAGEL'.

'Mass,achusrtts 721iepe :f ;;.armacy and Allied Health Sciances. Easton. MA 02115, and Department :: alcC.errjtry, Imcrob~olagy. and :.'a;ecular tenet~cs, University of Rhode Islanc. i ( i n g s i z > , ?.I 02881.

CilLate e;tin er.a:::ts considerable sequence divergence from mammalian actin, and thers 15 aian d high degree of actin sequence varrabrllty within the phylum Clllophcri. nhile S,c;rostomum actin has been reported to be undetectable by myosin S-1 decczitnn c z L::.:.ase bindinq criteria. actir :n the oral apparatus has been Structurall/ and f':-.-r::anally implicated i n Pdrdmecim phaqacytos15, and many laboratories hc're Cha:LTI?T1zed cytochalasin B 5 e ~ s 1 t l v ~ t y of PdrdmeCiUm and T e t r d h y m e n d phrpsome ?:.-ztiun. We have therefore recently Characterized the

. . . drhydrocytochHlrsln B 1 3 ) maxrmaiiy and ce'zerslbly lnhlblts the rate of phagosome POnnaTlOn, wk::;le aignlfiesntly less inhibition 1s Observed at the same molar C0nCentTa:LOn of zyr::halasins 8 . C. 0. E, or J . Interestingly, DHCB 15 also the only cytochalasin tested that inhibits Splrostomum contraction, for which we have p r e v l o u s l . hnwtr5s;:ed the involvement of an actin-dependent signal transduction p r x e s s . I5ilDltion of Spirostomvm phaqocytosiz. by cytochalasina was associated wit? the f ~ r . a : i a n of an excessively large, Cytostome-as5ociated phaqosome. indir3ting :ha! cytochalasins inhibit phaqosame separation from the cytostome as ha5 Seen deszzrbed 1" Paramecium and Tetrahymend. Preliminary result. indicate that =lllarY :orLllty 1s strmulated by cytochalasms. The relative cytochalasin PO:dnCleS ?>: :Illate phaqoqtosis inhibition are very different from those reported 5 1 Inh:x:ion O f actin-dependant mammalian cell motility. These results theref::? SUPFJ:: ;he idea that ciliate actins differ markedly from mammalian aCtl:l in z,rzchalasin binding prapert:es, and indicate that cytochalasins m y be uss:~: drugs in elucidating the e l u s ~ v e role of actin in clllate rnOtll>t_'.

5 Random movements of Soil Amebas, H. LEVANOOWSKY and F.L. SCHUSTER, Haskins Laboratories, Pace U., N.Y. NY 10038 and Brooklyn college, CUNY, Brooklyn, NY 11210.

Visual assays and videomicroscopy were used to record and analyze movements of soil amebas in the absence of chemical signal gradients. Seventeen isolates of amebas belonging to a genera, including several potential pathogens, were studied. Recordings of movements on glass or plastic surfaces in saline solutions or liquid media were made over periods ot 15-60 min, and tracks of individual cells were then traced at intervals of 1 or 2 min onto acetate overlay sheets. Mean and variance of speed and turning angle were computed, as well as the McCutcheon index (total displacement from the starting point divided by the distance traveled) and the mean square displacement. Dispersion followed a power law: log mean square displacement plotted against log time gave a straight line with slope between 1 and 2, usually closer to 2. Random walk theory predicts a slope of 1 for Gaussian dispersion and 2 f o r "ballistic" dispersion. Thus, in the time scale of these experiments, the amebas dispersed more rapidly than would be expected from a Gaussian model. This would be an advantage in populations searching to r food. Random movements of soil amebas may be approxinated by a 1-parameter class of random processes termed Levy walks, which includes Gaussian and ballistic dispersion as special cases at opposite extremes of the parameter's range.

2A ABSTRACTS

6 aharoaap.orp aaaptation to repollento in Pmrame-ziun and Totrahp- m a . T.x, Hennessey, H.G. Xuruvilla and X . Y . Kim, uept. or slol. Sc:.., S.U.N.Y.A.B., Buffalo, N.Y. 14260

Chenosenrory adaptation is a proceea by which ciliates such as Paramecium and Tetrahymcna modify t.heir responsiveness to charnorepellents like GTP and lysozyme. These chemorepellents CaJse somatic depolarizinq receptor potentials, ciliary Ca++- based action potentials and consquent backward swimming at non- toxic (nX to US) concentratlons. High aftinity CYtracOlLular receptors have been shown for both GTP and lyrozyme, with RD VdlUeS ox a h + low and 7w respPctively. while these repellents initially cause obvious bouts of backward swimming, normal for- ward swinming resumes after 5-10 min. in either 1 O W GTP or 0.luH lysozyme. This behavioral adaptation to I O U GTP is correlated with a decreased frequency of GTP-induced receptor potentials

ithout m y fhangc in their axplitud*=.) and a loss of surface "P GTP binding sitqs. A l l of these changes are reversible within LC nin- after, removal of the extracellular GTP. This sugsepCS that adaptation is due to reversible receptm down-regulation. Behavioral adaptation to lysozyme causes a dacreaee i tho s w a t - it rec4ptor potential amplitude, 1oes a€ sur€ace 'tI lysozyme receptors and forvard swimming. These changes are also reverslble within 10 lain. after removal of lysozyme. Adaptation to either repellent is sp cific. GTP adapted cells still respond to lyso- zl'me and bind 'FI lysozyme normally and vice-versa. Repellent adapted cells also nave normal responscs to ionic stirnulation (Ha++, K C . Na+ or TF%+) and chemoattractants. The GTP receptor hos boon identified by photoaffinity labeling to be about 50kO but it has not yet been purified. The lysozyme receptor has been purified (mol.ut-45kO) and antibodies to it block the lyrozyme responses but not the GTP responses. W e propoae that there ere separaee GTP and lysozyme rcocptorr t h a t ire independently and s-?ocifically down-rqulatad during cbemosonsory adaptation. E'itracolliilar recognition of these normally intracallular com- poundr may be used as a slgnal for general cell l ye i s , a situa- tion vorthy of avoidance. Although me exact physioloqrcal roles far these repellents arc Unknown, the ciliates have invested considerable enerqy in dcveloping specific receptors and modifia- ble raspoases to these chemorepellents.

7 Microscopic Studies or Exocytosis in Ni(Ac), Immobilized Paramecium lelmuerljq

SERGE1 LEVIS and BIRGIT If SATIR, Department of Anatomy mid Structural Biology, Albert Einstein College of Medicine, Bronu, NY, 10461.

Synchro-ous exocytosis in Paramecium can be stimulated in a Ca2+-dependent manner upon addition o i the non-lethal secretagogue lysozyme. The exocytic site in Paramecium i s marked in freeze fracture electron microscopy by a rosette of intramembrane particles. surrounded by ?.LO outer nngs of smaller particles. Ni2+ was earlier shown to inhibit cell motility in permeablized ;elis (Larsen and Satir.1991, I. Cell. Sci. 99, 33). High speed analysts of the process of exoc:.tosis (trichocyst matrix expansion) was performed on Ni'+-immobiIized cells. The time (0-30 nin) and concentration (0-300 pM) dependent effects of Ni(Ac), were studied on motility and sxocytosis. Our results showed that Ni(Ac), immobilizes Paramecium wilhout any effect on exocytosis. This was confirmed by freeze-fracture analysis which showed normal exocytic uluastrxture. Complete inhibition was reached after 15 min exposure to 200 pM Ni(Ac), and the :ifect of Ni" on motility was completely reversible for up to 3 hours. We have measured the ra:e of trichocyst matrix expansion upon stimulation with 100 pM lysozyme. For this high speed aalysis we used late log phase Poromecium cells exposed to 100 pM Ni(Ac), lor 15 min. High speed video sequences (200 irameslsec) were digitized and further analyzed using image processing techniques. The matnx expansion took place in a linear manner reaching i t s final length (-JOpm) in under 20 msec. This suggest that membrane fusion takes place on the msec scale.

8 Biophysical study of outer arm dynein and its regulation, Toshikazu

Hamasaki, Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, NY ;0461

Ciliary ceat is mainly powered by a mechanochemical activity of ciliary outer dynein arms. To understand how dynein arms work, we have determined !he relationship teiween microtubule length and translocation velocity from recordings of bovine brain nicrotubules translocating over a Paramecium 22s dynein (isolated form of the outer dyctin arm) substratum in an in vitro assay chamber. For comparison with untreated sardes . the 22s dynein has been subjecteti to detergent Triton X-100 andlor to pretreatments that induce phosphorylation of an associated 29 kDa regulatory light chain (p29: Barkalow eta/, 1994, J. Cell Biol. 126:727-735). This CAMP-mediated signal tranduction pathway is shown to increase ciliary beat so that Paramecium cells swim faster upon szmulation. We applied a kinetic analysis method. similar to those used in studying enzyme kinetics Assuming that dynein molecules are located randomly on a glass substraun and that activity is stochastic. we have determined maximum velocity (v,) and duty Chase ratio (0, the fraction of cycle time when dynein strongly attaches to and trans1oca:es the microtubule v, from CAMP-phosphorylated dynein is 40-50% higher than its matched control, whereas f seems constant around 0.01 regardless of the phosphorylaticn state of the dynein. This result confirms that the dynein mechnochemical cycle of a cilia:2 is regulated by phosphorylation of its regulatory light chain.

9 Evaluation of the Utility and Accuracy of Quantitative Protargol Stain in

Analysis of Salt Marsh Pan Ciliate Communities, JESSICA K. NELSON and MARK D. JOHNSON, Department of Life Sciences, University of New England, Biddeford, ME 04005.

Ciliate diversity and dynamics in salt marsh environments have not been extensively studied due to methodological difficulties. In other aquatic environments, i i

quantitative protargol stain (QPS) has been used, resulting in silver-stained ciliates which can be accurately identified. Enrichment cultures of ciliate isolates and then whole samples collected from a salt marsh pan in Biddeford. Maine, were subjected tc QPS to evaluate its accuracy and utility in this habitat. Ciliates were enumerated by live count, after fixation with Lugol's iodine, after Bouin's treatment, and after the final protargol stain. For most ciliates tested, significant losses occurred during the protargol stain procedure. However, in one ciliate species the most significant loss occurred during Lugol's fixation. Ciliate losses between live counts and the final protargol stain were comparable for cultured ciliates (37% loss) and natural salt marst assemblages (43% loss). We do feel that using QPS for some salt marsh samples is possible. However, enumeration by live count andlor after staining with Lugol's is recommended lo guard against error due to loss of delicate organisms or obfuscation of small forms by debris in the silver stained preparations.

10 Host Specificih of the Parasitic Dinoflagellate Amoebophoo ' e m u . FELISA L.

WOLFE, Oberlin College and Conservatory Oberlm, OH 44074 and D. W A W E COATS Smthsonian Enwonmental Research Center Edgewater, M D 21037

The protist Amoebophrya cernlit, a fatal intracelluiar parasite of dinoflagellates, I S itself rewgnmd as a member o f the Dmoflagellata It IS the only species of Amoebophrya know to parasitize free-limg dmoflagellates, however, recent work has show that A ceraOi mamtamed UI cultures of G)mnodinrrm rongeineum do not mfen several other dmoflagellate species dumg short- term (24 h) mcubations Tne study presented here exarmned the abillty of A cerfliii e x G sangirrnesm to infect alternate host species dumg long-term exposures Two of the four flasks contaming 500 ml of mxed host culture (Cemrrirm / ? m a G sangmeurn Gyrodrnium iuncareniim and Scrippsiella irochordea at 2 5 x 10' cells ml I , each) were moculated with 25 G sanguineurn m late-rtage mfection T h e two remammg flasks served as controls and &d not receive parasites Cultures were rnamtamed at 2 3 T on a 14 10 light dark cycle, wmth CWI white fluorescent bulbs prowdmg -IOG pm m s ' Samples (20 ml) collected daily over a two week pen4 were fixed UI Bourn's fluid, and processed by the quantitative protargol technique to detemune parasite prevalence Host abundance was obtamed by countmg cells present m I-ml of fixed sample usmg Sedgvnck- Rafter chambers All four host species exhibited exponential growth m control flasks, while only C /?ma G uncatcnum, and S rrochoideo did so m the presence of A ceralii G sanguineurn m expenmental flasks shoued positive growth for 3 4 days and then abruptly declmed to near zero as A ceratii approached 100% mfenion levels m that species No mfenions were observed in the h e r dmoflagellate species Tnese hdmgs suggest that bloom-formmg, manne dmoflagellates may be mfected by more than one species of Amoehophrya. with what has been prenously called A ceralll representmg a species complex

11

12

ABSTRACTS

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3A

U l t r a s t r u c t u r a l Evtdence for Host a n d Bacter la l E n d o s y m b l o n t interaction i n Euplotes. JOHN J. RUFFOLO, Henry M. Jackson Foundation for the Advancement a1 Mllitary Medicine. Rockviile. MD. 20852.

In Eupiotes eurysiomus the major type of cytoplasmic bacleriai endosymbiont is abaut 0.5 pm in dlameter and 3-8 pm long. has a Gram-negative ceii Wall morphology, has dlslinct multiple nucleoids and internal membrane diffarentiations. and is sumunded by a ho6t cyfoplasmic membrane with bound ribosomes. The surrounding membrane 1s structurally equivatent to rough sndoplasmic reticulum and it is reasonable to assume that proteins synthesized on the bound ribosomes are incorporated into the membrane structure or are deposited Insode the membrane compartment. Considenng that the bacterial endosymbionts are maintained i n the h o g cytoplasm. that they grow and divide within the membranous companment and are distributed and transmitted among progeny mi ls during host cell reproduction, and that host cells and symbionrs have a mutually dependent relationship for g r o w h and suwival. it is reasonable to expea that host-symbiont interadions are mediated by the OOmpdRmentel membrane. UltrastruOural ObseNafians have revealed examples of a band of donre material 3n the host's cvtoplasmic slde 01 the membrane surrounding a bacterial endosYmbiont. The dense band appears to form a ring around the comoanment and some mnfigurations suggest it is contractile. A few images suggest that the dense band constricts tha membrane compartment at a site where the bacterium may divide. If the dense band truly marks a ifssion site in the bacterium, then

I s reasonable to SuPPXe 11s Presence and location are determined by the presence and location o f the bactenal Rssion site.

13 Specialization of Life Cycle Stages of a Per i t r ich Ciliate f o r Planktonic and Symbiotic Existence, JOHN C. CLAMP, Department of Biology, North Carolina Central Unlvefs 3, Durham, NC 27707.

pattern in way: :hat can Se related to their life as symbionts on planktonic diatoms that are somec Tes present in rather low numbers. Living trophonts attached in fissures betweel cells in chains of the planktOfllC diatom Chaetoceros sp. were observed in W~EI mounts Under the compound microscope and videotaped. AS in typical peritricrs, one daughter from an asexual division usually stayed on the parental stalk as a trophonr, and the other became a motile, dispersive telotroch; however, tropi-3nts held mder a CoversliD too long or attached to moribund Chaetoceros frequently divided to produce two telotrochs instead. This would maximize dispcsal during times of stress in addition to abandoning a deteriorating substrate. By csntrast, typical peritrich trophonts under stress simply transform into telotrochs .vlthout dividing. Typical telotrochs swim and explore Substrates by giialng wi th t h i aboral scopula. a stalk-secreting organelle. held close to the surface Telotrochs of V xeanica do not swim and appear uninterested in exploring sunstrates o th f * than chacroceros, which they walk over with the scopula held off the surface usir? their locomotory cilia as "legs". Typical telotrochs flatten the body and scopula ag2.nst a surface when cementing to it. but those of v. oceanica inject the scopula ber.veen t w o diatoms in the host chain by elongating the aboral end

The life cyc 1 of the peritrich ciliate Vorricella oceanica differs from rhe typical

14 T h e Conserved T e r m i n i of Pnrnrneciiira a n d Eiip lo tes crnss i is I n t e r n a l El ini inated Sequences Resemble !he Ends of Tec a n d Tc l - re la ted Transposons, L A W R E N C E A. K L O B U T C H E R ' , M A R Y E L L E N JACOBS', a n d G L E N N H E R R I C K ' .

i ty of Connecticut Health Center, Farmington. CT 06030. Molecular Biology. University of Utah School o i

Foilowing maring in ciliated protozoa, a copy of the micronucleus is rrmsfomzd into a tmnscnptionall! x t i , e macronqcleus. Macronucleardeveiopment e n u l s extensi\e DNA rcarrangement, including the excision of large numbers of interstitial segments of D N A (internal eliminated sequexes) from the chromosomes with rejoining of flanlclng sequences. Two types ol JESS have been icsniilied in the hypotnchous ciliates: 1) large families of transposons that are related to the wid?!). distnbuted Tcl-mnner-ISi53O family of elements, and 2) smaller segmenu 01- D N A bounded b! short direct repeats. I t has been suggested that the short IESs represent degenerate copier . ~ f transpions To investigate this. we have used a statistically-bzed method to analyze the termi;d sequences for twenty short IESs in Pwmecaori and seven short lESs in Dipl01e.r c r u s i u in each case, sshort consewed inverted terminal repeat ~ v z identified The consensus sequenzes of the terminal invert repeats are similar to the ends of the developmentally cvcised Tcc transxsons of O~plotercrmms. and more generally to the ends of members of ihc Tc l - i~ in t i r r - IS6 .~~~ family o1clernenu. supporting the notion that short IESs arc denvcd irom lranspocon.; .A r ,x ie l for the in\olvcment of t r a n s ~ ~ o n ~ in the DNA exciswn process 01 inacronuclcdr derclopment nil1 be presented

A n Unusual I i istone H3 Tar-geted to the Developing iMacronucleus dur ing !he Period of D N A Deletion in Biiplofer crnssris, S U S M I T A CHOSH' , Z H O N C LING', CI IRISTOPHER M. TEBEAU', C A R O L Y N L. JAHN'. and L A W R E N C E A. K L O B U T C H E R ' , 'Department of Biwhcmistr).. Universit! 01 Connecucut Health Ccntcr, Fnrmingion, CT 06030. and 'Department of Cell and Molecular Biolugy. Nonhwcstern Univcrciiy Medical School, 303 h r l Cliicsgo A \ e , Chicago. ILF.0611

A scries of genes ha\c been isoialcd ilia1 are cxprcssed esclusi \c l ) duiing niacronuclcar dcrciopment in the ciliatc Oiplfflc.> crmsio. Onc such gene. c m ~ l , cncodcc d prorein tit31 15

-758 identical to conventional hislone H3 protcins. but i t has an unusual N-icrminal region containing an additional 15 amino acids. Tianscnpts of the coiiZL31 gene accumulatc at the sun 01 macriinuclear development .ind appear to rcplacc those of the vcgeativcly ciprcsscd histanc H3 gene. A pol!clonal antikxly to the conZB 1 protein h a been used to demons1r;lle that lhe protein is produced pnmanl! dunng the polytcnc chromosome sugc o l macrunuclcar development, a pen& when > 100,oOO D N A cscision cvents occur, and that conZB I i s urgctcd exclusivclv to the developing mdcronuclcus. Wc have also carned out microcwcal nucleuc digcsts olLhromatin and analyxd them by hybndimtion with probes specilic for micronuclear and macronuc1ur sequenccs. The results indicate that there is a change in nucleosomc spacing that conelates n i t h the maximal espression of the conZDl gene The unusual conZB i histonc H3 may be involved i n generating yxcidl izcd chromatin domains that target DNA scqucnccs for cither rranscnptional acti\ation and retention i n the macronucleus or hctcrochrnmatiz~lion m d climination

16 A centriwlike protein IS a component of a basal-body sheath in Euplotes.

JOHN A. KLOETZEL. W. T. HORICH and T. M. KOLB, Department 01 Blologtcai Sciences. University of Maryland Baltimore County, Catonsvilie. Maryland 21250

Centrin (or caltractin) 1s a Ca++-binding. 20kDa protein. tirst identified m tibrous connectors associated with the basai bod,es of green aigae, that Since has been found to be highly conserved and widely distributed. Centrin proteins are found in centrosomes of higher cells, postulated cenfrin Iunctfons include roles in basal body duplication and positioning. as well as a demonstrated role in contraction. A monoclonal antibody (MAb) against Chfamydornonas centrin (20H5, kindly provided by Jeff Salisbury) was used to probe for centrin-like proteins in Eupiotes aediculalus. On immunobtots of Eupfoles whole-cell protein extracts or Tnton.htgh salt (THS, or 'cytosketetai') preparations, a 2OkDa protein reacted strongly with this MAb. lmmunotluorescence microscopy revealed anti-centrin staining associated with each individual basa! body, whether in dorsal 'bristle' rows (diplosomes) or in ventral polykinettds (cirri. paroral membranelie. rnrmbranelles of the adoral zone). immunogold staining of ultrathin Sections showed gold particles specificaliy associated with basal bodies and cilia. in THS-extracted conical residues, which are devoid 01 cilia and almost all tubulin. anti-centrin immunogold labeling remained associated with residual filamentous structures located where basai bodies normally reside. grouped within the cagein protein.based scaffolds or 'cages' of the ventral polykinetids. Only slight indications of kinetosome 9-lold organization remain in such high-salt (1 5 M KCI)-treated preparations: i t appears lhat the centnn-like protein 1s a Component 01 a fibrous sheath encompassing each basal body. A ioie for centrin in linking basal bodies to the cage matrix within poiykinetids. or possibly a more active motile role in polykinetid functioning. are anractive hypotheses.

in addition to basal body staining. imrnunolluorescence preparations reveal 20H5 reactivity, clearly above background, in Other locations along the microtubule bundles running anteriorly from the transverse cirri: and, notably. In a laterally striated sheet across the entire back wail of the buccal cavity (peristome) A potential rote In prey capture and/or food vacuole lormation can be suggested io i a centrin like protein In thts latter location, given centrin's known contractile properties.

17 ATlr r e c - p t i o n in t h e c i l i a t e s Paramecium and T*trahynan.. TM. l lennessey and W.X. X i m , Oept. o f B i o l . Sc l . . S.U.N.Y.A.B., Butfa- lo N.Y. 1 4 2 6 0

Many e a s r y o t j c c e l l 6 eons8 and r e s p o n d t o e x t r a c e l l u l a r ATP by way o f XTP E P C C L ~ ~ R p u r i n e r q i c r e c e o t o r s . These r e c e p t o r s have c l r s s i c a l l y b e e n c h a r a c t e r i z e d b y t h e o r d e r of p o t e n c i e s ot various p u r i n e r g i c a g o n i s t s . P r e v i o u s w o r k w i t h Paramecium suq- g e s t e d t h a t the c i l i a t e s r e p r e s e n t a new c l a s s i f i c a t i o n of puri- n e r q r c r e c e p t o r s because they r e s p o n d p r i r a r i l y t o GTP a n d n o t ATP u n d e r t h e a s s a y c o n d i t i o n s u s e d ( C l a r k e t a l . , 1 9 9 3 , 1 9 9 7 ) . E x t e r n a l CTP i s a d ~ p o l a r i z i n q c h e m o r e p e l l e n t d u e t o a c t i v a t i o n of a r e c e p t o r - o p e r a t e d s o m m t i c Ca++ c o n d u c t a n c e . W h l b o t h P a r a m e c i u m a n d P e t r a h y m e n a h a v e n o v e l , hlqh a r f l n l t y "P GTP b ind inq r e c e p t o r s , t h e s e c i l i a r e a also r e s p o n d t o ATP under a p p r o p r i a t e c o n d i t i o n s . T h e r e w o n that ATP r e c e p t i o n was n o t Se-n p r e v i o u s l y is t h a t t h e common b e h a v i o r a l and e l e c t r o p b y s i o - l o q i c a l s o l u t i o n s c o n t a i n e d high (mu) o o n c e n t r a t i o n e of Ca++ a n d Hgc+. T h L s c o n d i t i o n was i d e a l f o r a c t i v a t i n g a d e d i c a t e d Cat+ a n d / o r W g H dependent ecto-ATPase t h a t p r e f e r s ATP over GTP a s a Substrate b y 4:l ( s m i t h st a1. ,1997) . s i n c e the eoto-ATPa6e i s d i s t r i b u t c d on both t h e c i l i a r y and body membranes and t h e pur i - n e r q i e ' r r c o p t o r s a r e o n t h e body, much of t h e ATP was h y d r o l y z e d b e f o r e i t c o u l d reach t h e r e c e p t o r , I n t e s t s o l u t i o n s c o n t a l n l n g low Ca++ (and n o added H g H ) , e l e c t r o p h y s i o l o g i c a l and b e h a v i o r a l r e s p o n s e s t o e x t e r n a l ATP i n c r e a s e d as t h e Ca++ w a s l o w e r e d t o un l e v e l s . F u r t h e r m o r e . n o n - h y d r o l y z a b l e ATP a n a l o g s ( l i k e b e t a - g s m a D o t h y l e n s ICP) were e f f e c t i v e d e p o l a r i z i n q c e m o r a p e l l e n t s a t c o n c e n t r a t i o n s a s low as 1 0 M . H i g h a f f i n i t y "P ATP b i n d i n q w I 5 seen u n d e r t h e s e c o n d i t i o n s t h a t c o u l d be e t r e c t i v r l y comp ec. by c o l d ATP or = e t h y l e n e ATP but not by GTP. G i m l l a r l y , % GYP bindinq was cozpeted b y c o l d CTP but n o t by ETP. GTP adapted cc-11s) v h i o h h a d l a s t t h e i r r e s p o n s i v e n e s s t o GTP due t o loss of s t r f a c e GTP r e c e p t s r s , s t i l l responded n o r m a l l y t o ATP and vice- v e r s a . T o g e t h e r . ttis Suqqests that t h e s e c e l l s have s e p a r a t e ATP arid GTP r e c e p t o r s t h a t c a n ba i n a e p e n d e n t l y d m - r e g u l a t e d d u r i n g s p e c i f i c chenasensory a d a p t a t i o n . P r e l i m i n a r y evidence shows t h a t a d d i t i o n of ATP during mating d r a m a t i c a l l y d e c r e a s e s t h e number 01: m a t i n g pairs ir. T a t r a h p e n a . s u g g e s t i n g that ATP (or o n e of it:% m e t a b o l i t e s ) :ay b e a f f e c t i n g e i t h e r t h e c e l l r e c o g n i t i o n , c e l l a d h e s i o n or d i s e n g a g i n g s t e p s of t h e m a t i n g response.

4A ABSTRACTS

18 Affinity Purified Con A-Binding Ckliary Polypeptides From Starved And Fed Tetrahvmena

Thermophila. C.A. DRISCOLL and L.A. HUFNAGEL. University of Rhode Island Kingston RI, 02881

Evidence 'or SlaNatlon-lnouced changes In Concanavalrn A (Con A) bindlng polypeptldes of ciliary membranes of I themODhila and for a relationship of such changes to development of matjng competency based on lectin-blotting studies has been reported from our laboratory (Cheng and Hufnagel Dev Genet 13 26-33 1992) We now have conducted a similar experimental analysis of polypeptides puri'%3 from ciliary membrane-rich fraclons by Con A affinty Chromatography Chary membrane fractio~s were isolated from two wild lype Stralns (CU427 3 and CU428 1 ) and a mating mutant able to cosmulate wits of complementary matlng type but not able to enter nto pajr formatton (RH179E1) Afler 'hey were solubilized with Nonidet P-40 or Triton X-100 fractions were subjected to Con A-Sepharose affinity chromatography followed by acetone precrpllallon to remove detergent The resulting fraclions znnched for Con A-binding polypeptides were analyzed by SDS PAGEisllver In some experiments motease mhioitors (PMSF BAM and ACA) were used extenswely throughout the experimental procedures whereas in other experiments use of mhibilors was limlled lo membrane isolation Steps Comparisons were made of fractions from cells In late exponentlal phase and from cells starved overnight n 10 mM Tris buffer pH 7 2 The results we obtamed are consistent with earher findings that 1 ) starvat~on of wild type cells leads to several changes m Con A bmdlng ciliary membrane polypeptides 2) '+ese changes are shut off in slrain RH179E1 and 3) a consplwous low rnolecuiar weight polypeptide vanishes following overnight starvation ofwild type cells but does not dlsappear In the mutant However under the most stringent use Of prolease lnhlbltors our results suggest that the native molecular weight of this polypeptide 8s 28 Kda rather than 25 KDa as previously reported Our findings lend funher suppotl lo the idea fhat changes In ciliary membrane polypeptldes or thelr glycosylation patterns are neeaed for the development of palrlng competency In matlng I lhermophila and prompt our c- osily about the possible roles In mating of several glycosylaled clllary prolerns including the 28 Kda rnOleWle

19 W h a t Does Molecular Biology O f f e r Ecological S t u d i e s of Protists?

D A V I D A. CARON, REBECCA J. GAST A N D EE LIN LIM, Depar tment of Biology, W a o d s H o l e Oceanographic Insti tution, W o o d s Hole , M A 10543.

microalgae a n d pro tozoa in na tura l ecosystems h a s a d v a n c e d considerably d u r i n g the 1st several decades In particular, the basic nutri t ional modes , t rophic roles a n d geographical distributions of s o m e of t h e larger and m o r e c o n s p i c u o c j pro t i s t s have been established fundamenta l issues still exist tha t a r e difficult o r imposs ib le to resolve us ing ex tan t ecoiogical methodology. N e w investigative approaches involv ing m o d e r n molecular biological techniques have begun to a p p e a r in recent years tha t m a y b? capable of address ing s o m e of these long-standing ecological ques t ions This lecture will p r o v i d e an overv iew of s i tua t ions in w h i c h extant met6,odolog). lacks the abil i ty t o resolve impor tan t ques t ions of protistan y s c i e s diversity, c o m m u n i t y s t ruc ture a n d biogeography, as well a s p r o v i d e s o m e examplez w h e r e molecular techniques a r e b e i n g developed to provide new insights a n d answers to these questions.

O u r unders tanding of the ecological a n d biogeochemical roles of

Nevertheless, severa l

20 Ozone Detoxification of Dinoflagellate Poisons. Potential Treatment for Aquaria and

Aquafarms. WALTER J. BLOGOSLAWSKI, NOAA, NEFSC, NMFS, Milford Laboratory. 212 Rogers .Ale., Milford, CT 06460

Some marine dinotlagellates possess potent neurotoxins that advzrscly dfect tile h e d t h ot marine fish, tnvenebrates, birds, and mammals. including those of terrestrial origin which consume s a f o o d Alexuiidriwn sps. produce paralytic shellfish po~son(PSP) , which when concentrated in the tissues of various filter-feeding molluscs. make the molluscs toxic to venebrates.

A fifteen-year series of sxperimrnts indicated that ozone gas can be effective in detoxification of letrodoxin( puffer f i sh suborder Gjmnodontes). PSP from the dinoflagellatea Alexmdri i ini lanrureiix and Altrundriiiiii txcauimini, 2nd red tide poisons from the dinoflagellate. Gy!nnodi,irron breve. the agent responsible for Carribean fish kills.

A review of theie experimenta is presented along with proposed methods for ozone tredlment of seawater supplies of aquaria and dquafarms.

21 Detection of the Arginine Dihydrolase Pathway and other Selected Enzyme

Activities in Hexarnica in€lata, Ann C. BilleCz, Donald 0 . Lindmark and Nigel Yarlett. Department of Siology. Cleveland State University. Cleveland. ox 14115 and Haskins Laborac?rles. Pace University, New York, NY 10038.

Hexamita sp. belonging to the order Dzplomonadlda include both parasitic and free living species. Small-subunlt ribosomal PNA sequencing suggests that these protozoans are one of the earliest branches Of eukaryotes. The following enzyme activities lmU/mg protelnl were detected in H . m: a r g l n m e deirnmase (3.29). anabolic ornithine carbamyltransferase IOCT) ( 2 2 9 0 1 . and arnithine decarbavlase (5.7 x 10-4) suggesting the presence of an arginine dihydrolase pathway. This pathway may be used in the production of polyamines. The polyamrne content in Y. inf, as determined by XPLC analysis, is as follows (mol/mg protein): spermine (10.2). spermidhe ( 7 . 0 1 , and putrescine (NDI

Anabol ic OCT has Seen partlally purified U s i q drfferencial sedimentatla?, ammonlm sulfate fractionation. and gel filcratlon HPLC. OCT has a native molecular weight of 130 kDa as determined by gel filtration YPLC. Iniciil characterization of OCT actrvity shows the optimal temperature and pH to be 37' C and 8 . 5 . The apparent Km and vmax for ornrthine are 0.49 mM and 3.41 U/mg atd for carbamyl phosphate 0 . 4 2 mM and 2.15 u/mg respectively. In addltion to tie enzymes Of the arginine dihydrolase pathway the following enzyme activiciss lmU/mg protein) were detected in H . inf: acid phosphataee 1 4 5 1 . 8 - U - acetylglucasaminidase 145) , NROH dehydrogenase (3521 , malate dehydr0rJena;e Ldecarboqlatingl 1891, malate dehydrogenase (1729). pyruvate ferredoxm oxidoreductase 112001, pyrophosphate dependent phosphofructokmase 120001, a.id pyruvate kinase (1251

22 Factors Influencing thc Feeding Ueliavior of the hliriitrophic Uinoflagellale

Cemfiurn furca. G A B R E L A W. SMALLEY, 1). JVAYNE COATS and E. JEREMY ADAM. SmithsCNan Environmental Research Center, Edgewater. MD 21037. and D U N E I;. STOECKEK, Horn Point Environmental Laboratory. Cambridge, MD 21613.

Durtng thz summer of 1995 and 1996. several it! SIN feeding experunents were conducttd along the main ;IXLS of the Chesapeake Bay to explore spatial aspects of mkotrophy tn tlie dinoflagellate Cerariim f i r m . Physical facrors influencing the feeding rate of the dinoflagella e were also considered. We employed a method using fluorescent rmcrospheres to lab4 inicrophagous protozoa and followed ingestion of these labeled organisms by C furca. Feedirg rates varied grexly between the two years, but were w i t h the range previously reported f w other large mixouophic dmoflagellates. Analysis of food vacuole contents revealed that C. pirca was feedtng predominantly on smU ohgornch cdiates. Both light and nulnent mvuonmeiit seemed to influence feeding rates. Lower feeding rates were observed when C. furco was kept in complete darkness. Increased nitrogen concentrations seemed to decrease feeding rates. When ingestion of labetd prey was followed over a 48-hour tune period. a die1 feeding pattern emerged, charactenzed by c!evated ingestion during the day.

23 Feeding Ecoloa. of Planktonic Amoebae in Chesapeake Bay. RICHARD W. PIERCE and D. WAYNE COATS Smithsonian Em;ronmental Research Center, Edgewater, !d!3 21037

Planktomi amoebae are often overlooked in estuarine systems Traditional methods of fixation and examination of plankton samples often fail to detect these organisms Through the use of Quantitatke Protargol Staining, piankonic heliozoa were found to be a regular and often abundant component of the plankton community of Chesapeake Bay Heliozoa were observed throughout the b2y during the warmer months and could exceed densities of 1000 cells 1_'

Ciliates are 2 major component of heliozoa diets To examine feeding of heliozoa, samples containing both ciliates and heliozoa at in situ concentrations were labeled with I p n fluorescent microspheres Ciliates rapidly become labeled allowing detection within heliozoa food vacuoles Two ciliates, a Strobilidium sp 30 pm in diameter and a Pleuroirema sp were the primary ciliate prey items, although a wide range of ciliate taxa were ingested Two other ciliates, Cyclidiiim sp and Uronema sp were also labeled and added at various concentrations Heliozoa feeding rates at in situ prey concentrations (-35 Strobrlidiiim & Pleiiroiiema d-') were 0 3 to 0 5 prey I heliozoa I hour. Feeding rates increased with prey concentration to a maximum of 3 35 prey I heliozoa I hour at concentrations of 1000 Cycliditim d-' Clearance rates ranged from 0 3 to 0 09 ml I heliozoa I day Both feeding and clearance rates suggest that at even I000 prey d-', feeding in this heliozoan is not saturated. At densities of more than a few heliozoa ml.', they may exert a significant grazing pressure on the planktonic ciliate populations of Chesapeake Bay

ABSTRACTS 5A

24 A n n u a l a b u n o a n c e and divers i ty o f ter rest r ia l g y m n a m o e b a e i n

s u r f a c e soil of a g r a s s y site in nor theastern U S . A,, 0. ROGER ANDERSCN, Biological Oceanography, Lamont-Doher ty Earth Observatory o f C o l u m b i a Univers i ty , Palisades, N. Y. 10964

The a b u n d a n c e and divers i ty o f g y m n a m o e b a e w e r e assessed at m o n t h l y 1n:ervais for a p e r i o d of 20 m o n t h s . increas ing ly r e c o g n i z g d to have a n important role i n n u t r i e n t minera l izat ion a n d soi l fert i l i ty. L i t t le is known, h o w e v e r , about a n n u a l var ia t ions i n a b u n d a n c e s o f terrestrial g y m n a m o e b a e , p o s s i b l y due t o l imi ta t ions in p r i o r t e c h n i q u e s for e n u m e r a t i n g them. U s i n g a n e w e r culturing methodology, a larger r a n g e of m o r p h o t y p e s c a n be detected. A b u n d a n c e s varied ':om 156 g-1 to 3,191 g.1 and v a r i e d substant ia l ly throughout the s a m p i i n g period, without a regular seasonal pat tern. available moisture aopears to be the major c o n t r o l l i n g factor f o r a b u n d a n c e s , u n l i k e a q u a t i c e n v i r o n m e n t s w h e r e t e m p e r a t u r e (seasonal i ty ) is a m o r e signif ican! var iab le. L a b o r a t o r y e x p e r i m e n t s with soil t a k e n f r o m the samplinG site s u p p o r t the h y p o t h e s i s that available m o i s t u r e is a p r i m a r y var iab le d e t e r m i n i n g abundance of ter rest r ia l g y r n n a m o e b a e a n d t h a t avai lab le o r g a n i c s is a s e c o n d a r y contr ibut ing f a c t o r

Terrest r ia i gymnamoebae a r e

The

25 A u t e c o l o g y a n d S y n e c o l o g y of a M i x o t r o p h i c Ciliate, MARK D. JOHNSON,

The relationship between the trophic behavior of an algaliciliate symbiosis and its function wllhin a

Department of Life Sciences. University of New England. Biddeford. ME 04005. AMELIA K WARD, Aquatic Biology Program, UniversiV of Alabama, Tuscaloosa. AL 35487.

pond ecosystem was investigated. Ophrydium versalile ( 0 F Muller) lorms macroscopic colonies up to 25 cm in diameter and depends nu:ntionally upon both filter feeding and photosynthetic productivity of endosymbiotic Chiorella. Feeding experiments were used to determine the ellect of light and temperature on trophic behavior. lccreased rate of filter feeding was the initial response to lowered light levels. Grkter than 24 hours darkmss induced zooid transformation to the telotroch/swarmer stage Teiotroch cells were found lo be positively phototropic. Attempted digestion of the endosymbiotic algae was the zooid response to prolonged darkness. Field data conlirmed the importance 01 these behavior options as responses to natural disturbances and in compensating for seasonal changes. Coiony primary productivity was measured monthly ,n the field with radiolabeled carbon, and rates 01 bacterivory were measured seasonatly. Summer rates 01 primary production and bacfenvory per Unit 01 colony surface area were higher than during any other season. However, high summer rates of bacterioplankton production and iimiled distrtbulion 01 the ctt'ate colonies diminished their importance lo lhe pond ecosystem in warm months. During the winter when insolation was lowest. 0 versatile colonies functioned primarily as bacterivores and colonized a greater portion of the wetland pond than during any other season. Low planktonic bacterial productivity in wnter combined with high clearance rates increased the impact of these ciliate colonies on planktonic microbial populations during that season.

26 A Survey of Protists as Indicators of Pollution in the Quinnipiac River, CT.

MARIA ILL4NA AYALA and AHTIIUR J. REPAK, School ofForestry and Environmental Studies, Yale University, New Haven, CT 065 I I & Dept Biological Sciences. QuiMipiac College. Hamden, CT 065 18

with the lebel ofpoilution Six sites along the Quinnipiac h v e r were monitored and urnpled from Southingon to Meriden, CT from July, 1996 to March, 1997 Ln addition to protozoan numbers and species identification the following physical parameters were measured. DO, p H and temperature Hot spots of pollution were noted at all sites dunng this penod oit ime .&\OVA analysis were used t o reflect a correlation between the physiochemical parameters and the Saprobic Index obtamed. Twenty seven different species of flagellates (5). testate amoebae ( I ) , heliozoa (1) and ciliates (10) were found at vanous times

A Saprobic Index was developed for species of prousta that correlates the species

27 Protists without mitochondria: an update on the status of the Archezoa hypothesis. ANDREW J. R O G E R t , STAFFAN G. SVARD*, FRANCES D. GILLIN* and MITCHELL L. SOGINt. b a y Paul Center lor Comparative Molecular Biology and Evolution. Maine Biological Laboratoly. Woods Hole, MA. 02543, *Deparfment 01 Pathology, University of California at San Diego Medical Center, San Diego, CA. 92103

Three amitochondriate protist lineages, tnchomonads, microsporidia and diplomonads. are basal to a81 other eukaryotes in 16s-like rDNA trees. One interpretation 01 this branching pattern IS the% groups diverged before the endosymbiotic event that introduced mitochondria into eukaryotc cells. Ho:vever. comparisons of hsp70, hsp60 and hsplO genes challenge this view. Previous heat Shock gene trees show that Inchomonad and microsporidian hsp genes share a commn evolutionary history with heat shock proteins localized in the mitochondria 01 olher eukaryotes. Furthermore, these sequences are specifically related to hamologs in the a Proteobacteria. the prokaryotic lineage implicated in milochondrial origins.

Here ' . e describe a similar yene sequence from the diplomonad Giaidfa fambfia. a representative 21 yet ano:her early diverging amitochondriate protist lineage. Southern and northern blots :ndicate that the Giardia hsp5O is encoded by a single copy gene that is expressed on a -2 kilobase transcript. Phylogenetic comparisons of hsp6O genes place the highly divergent Giarda sequence closest to the milochondrial and a-proteobacleriai lineages

These heat shock gene phylogenies suggest that diplomonads trichomonads and microsporidia may be descended from mitochondnon-bearing ancestors. Alternatwdy, these hsp genes may have originated from distinct a-proteobacterial endosymbioses formed transiently within the ancestors of these protist groups.

28 Tbe jakobid and retartarnoodd flagellates: keys to understanding early events in

mitochondria1 euksryote cvolufion. GERTRAUO BURGER', MARK A. FARMER*, MICHAEL W. GRAY', 8. FRANZ LAVGi, THOMAS A. NERAD' 2nd CRARLES J. O'KELLP,' D6partement de Biochimie, Univcrsiti de Monueal. C. P. 6128, succ. Cenhe-Ville. Monnial, PQ tI3C 37. Cnnada; ' Center for Advanced CiImSmrcml Rewnrch, University of Georgi4Athcos. GA 30602; ' Depamnent of Biochemistry. Dalhousie Univmity, Hdifur,NS B3H 4H7, CMsda; Protistology DepartmenL American Type Culture Collectios Rochill- MD 20852: ' Bigelow Labcntory for Ocem Scimces. P 0. Box 475, McKowo Powt, West Boothbay Harbor. ME 04575.

Jakobid flagellates (Himono, Jukobu, Rccfinomonar and the ncw genus Muimimonar) share nmcrous ulasmrcrural features with each other and with retorramonads, Q lineage of amitmhondrial protisrs fxqqucntly assigned to Archaezoa (ancestrally without mitcchonckia). Two addi t iod species of kc-l iving motiagellates, common in wastcwatm and previously arsigncdto Temamim (class Ileleroloborca). have ultmsmrctural fen- of the rctorlamonnd genus Ckzio-tir but unlike Chilomastir and similar to the jakobidr, possess well-dcvelopcd endomembw systems including Golgi. Mitofhondrial gonorncs of R. omericonn. J. bbero and .M jakob$ormt.r. completely scquenccd with data available on thc World Widc Web at

h n p : / / m e g P r ~ ~ . b c h . u m o n ~ ~ c ~ o ~ p / p r o j c c h l , prcsewe more cubaclcrial-like facahlres than m y other mitochondrial genomes sequenced lo date. The most ancestral stages of divcrsificatron of rnitachondriaIe c h r y o t c r may be conserved in these flagellates.

29 Digi ta l Imaging, Frame Grabbing. and Resource Dispersion: A new 11 eh site wi th an evolving image dnta base. Cnry W. Grimes, Department of Biology, Hofstra University, Hempstead, NY 11550

present in texts, laboraton, manuals, or published in scientific Journals. During this time, i have had innumerable requests for copies of some of the images that I personally have made in m y lab. This past Fall semester (F-96), I taught Protozoology and generated a large number of SEMs that I used for this course, simply because tl.: images irere not available eisewhere. Because the new SEMs are digital (as well as analogue) based, images can be "captured" in a state suitable for immediate retrieval via the internet. With the encouragement and aid of the Academic Computing Center at Hofstra, we have established an image gal lerj accessible to anyone with internet capabilities. The data ate available for personal andior instructional purposes at no charge (i.e., images may be downloaded as desired). The sire is currently overweight with protozoa, but many other types o f subjects are available as well. Our URL address is HTTP //www.Hofstra.edulweb/docs/sem/jndex/hrml Come give the site a visit; al l comments or suggestions on how to improve the site wi l l be welcomed.

For many years. use o f images for insvuctional purposes were limited LO those