bluuebunny/crossref_metadata_2025 huggingface dataset:
Sequence Diversity and Linkage Disequilibrium within the Merozoite Surface Protein‐1 (Msp‐1) Locus of Plasmodium falciparum: A Longitudinal Study in Brazil
Authors: DA SILVEIRA LUCIMEIRE A. , RIBEIRO WEBER L. , KIRCHGATTER KARIN , WUNDERLICH GERHARD , MATSUOKA HIROYUKI , TANABE KAZUYUKI , FERREIRA MARCELO U.
Published: July 2005

ABSTRACT. The merozoite surface protein‐1 (MSP‐1) is a major vaccine candidate for the asexual blood stage of malaria. We examined both the extent of sequence diversity in block 17, the 3′end of Msp‐1 gene coding for a 19‐kDa polypeptide (MSP‐119) putatively involved in red blood cell binding, and the patterns of linkage disequilibrium between polymorphic sites throughout the Msp‐1 locus. The parasite population sample consisted of Plasmodium falciparum isolates collected between 1985 and 1998 in Rondônia. an area of hypoendemic malaria transmission in the southwestern Brazilian Amazon. Results were summarized as follows. (I) Seven block‐17 sequence variants or haplotypes were found among 130 isolates, including two new haplotypes (novel combinations of previously reported amino acid replacements), here named Brazil‐1 (E‐TSR‐F) and Brazil‐2 (Q‐TSR‐F). (2) As previously shown for other Msp‐1 polymorphisms, frequencies of block‐17 haplotypes displayed significant temporal variation. (3) Extensive linkage disequilibrium was demonstrated between neighboring dimorphic sites within block 17, as well as between polymorphisms at the 5′and 3′ends of Msp‐1 (map distance range: 3.83–4.99 kb). (4) The overall patterns of linkage disequilibrium within Msp‐1 remained stable over a period of nearly one decade, and examples of possible ‘epidemic’ expansion of parasites carrying particular Msp‐1 alleles were found in the 1980s and 1990s. These results are discussed in relation to the population biology of P. falciparum and the development of malaria vaccines based on MSP‐1.
Light Microscopic Observations of Infraciliature and Morphogenesis in Six Species of Rumen Ostracodinium Ciliates
Authors: ITO AKIRA , MIYAZAKI YUTAKA , IMAI SOICHI
Published: July 2005

ABSTRACT. Infraciliature and morphogenesis of six rumen ciliates, Ostracodinium mammosum, O. munham, O, dilohum, O. rugaloricatum, O. iwawoi, and O. tiete are described from pyridinated silver carbonate‐impregnated specimens. These six Ostracodinium have a similar polybrachykinety arrangement, distinct from that of other ophryoscolecid ciliates and intermediate between those of O. gracile and O. damaliscus. Buccal infraciliature is composed of three polybrachykineties, a kinety loop, and paralabial kinetics. Small dorso‐adoral polybrachykinety, slender vestibular polybrachykinety, and kinety loop are characteristic. Dorsal infraciliature consists of the dorsal polybrachykinety that extends laterally along the dorsal side of the body. Morphogenesis is different from that of O. gracile, because the right end of ventral primordium extends dorsally to grow into a right primordium without separation.
Molecular Evidence for the Existence of Two Species of Marteilia in Europe
Authors: LE ROUX FREDERIQUE , LORENZO GEMA , PEYRET PIERRE , AUDEMARD CORINNE , FIGUERAS ANTONIO , VIVARÈS CHRISTIAN , GOUY MANOLO , BERTHE FRANCK
Published: July 2005

ABSTRACT. Marteilia refringens is one of the most significant pathogens of bivalve molluscs. Previous sequencing of the small subunit ribosomal RNA gene of M. refringens isolates derived from the infected mussels (Mytilus edulis and Mytilus galloprovinciallis) and the oyster (Ostrea edulis) in Europe did not reveal genetic polymorphisms despite indications from epizootiological data that distinct types may exist. We investigated the existence of polymorphisms in the internal transcribed spacer region of the ribosomal RNA genes. The sequences of this region proved to be clearly dimorphic among Marteilia from five sampling sites. The distribution of the two genetic types, named “O” and “M”, appeared to be linked to the host species, oysters and mussels, respectively. We therefore support the recognition of two species of Marteilia in Europe and propose that the “O” type corresponds to M. refringens and the “M” type to M. maurini.
The Rumen Ciliate Fauna of Domestic Sheep (Ovis ammon aires) from the Turkish Republic of Northern Cyprus
Authors: GÖÇMEN BAYRAM , DEHORITY BURK A. , TALU GÜL H. , RASTGELDY SAMIYE
Published: July 2005

ABSTRACT. Concentration and composition of ciliate protozoa in the families Ophryoscolecidae and Isotrichidae were determined in rumen contents of domestic sheep (Ovis ammon aries) from Cyprus. A total of five genera of Ophryoscolecidae were identified, Metadinium, Enoploplastron, Polyplastron, Epidinium, and Ophryoscolex, which included six species: Metadinium affine, Enoploplastron triloricatum, Polyplastron multivesiculatum, Epidinium ecaudatum, Epidinium graini, and Ophryoscolex purkynjei. Eight separate forms of Epidinium were identified (E. ecaudatum f. ecaudatum, E, e. f. caudatum, E. e. f. bicaudatum, E. e. f. tricaudatum, E. e. f. quadricaudatum, E. graini f. graini, E. g. f. caudatricoronatum, and E. g. f. caudaquadricoronatum), along with five forms of Ophryoscolex purkynjei (O. p. f. purkynjei, O. p. f. bifidobicinctus, O. p. f. bifidoquadricinctus, O. p. f. bicoronatus, O. p. f. tricoronatus, and O. p. f. quadricoronatus). Three species of Isotrichidae were observed, Isotricha intestinalis, I. prostoma, and Dasytricha ruminantium. This study reports new host records for three forms of Epidinium graini and Ophryoscolex purkynjei f. bifidobicinctus. The rumen fauna in the family Ophryoscolecidae from Cypriote domestic sheep appear to have limited diversity compared to those from Turkish and Far Eastern (Chinese/Japanese) sheep, while they are more diverse than those found in Western European (Scottish) and North American (Canadian/Alaskan) sheep.
On Core Jakobids and Excavate Taxa: The Ultrastructure of Jakoba incarcerata
Authors: SIMPSON ALASTAIR G. B. , PATTERSON DAVID J.
Published: July 2005

ABSTRACT. The cellular organisation of the ‘excavate’ flagellate Jakoba incarcerataBernard, Simpson and Patterson 2000 is described. Cells have one nucleus and dictyosome. The putative mitochondria lack cristae. Two flagella (anterior and posterior) insert anterior to the feeding groove. The posterior flagellum bears a dorsal vane. An ‘anterior’ microtubular root arises against the anterior basal body. Two main microtubular roots, left and right, and a singlet ‘root’ arise around the posterior basal body and support the groove. Non‐microtubular fibres termed ‘A’, ‘B’, ‘I’, and ‘composite’ associate with the right root. A multilaminar ‘C’ fibre associates with the left root. The cytoskeleton of J. incarcerata indicates a common ancestry with other excavate taxa (i.e. diplomonads, retortamonads, heteroloboseids, ‘core jakobids’, Malawimonas, Carpediemonas, and Trimastix). Overall, J. incarcerata is most similar to (other) core jakobids, namely Jakoba libera, Reclinomonas, and Histiona. We regard J. incarcerata as a core jakobid and identify the group by the synapomorphy ‘vanes restricted to dorsal side of the posterior flagellum’. The anterior root and position of the B fibre (and presence of dense inclusions in the cartwheels and a conscpicuous singlet root‐associated fibre) in J. incarcerata are novel for core jakobids and argue for close relationships with Trimastix and/or Heterolobosea. The C fibre is similar in substructure to the costal fibre of parabasalids and it is possible that the structures are homologous.
Archaebacterial Relationships of the Phosphoenolpyruvate Carboxykinase Gene Reveal Mosaicism of Giardia intestinalis Core Metabolism
Authors: SUGURI SETSUO , HENZE KATRIN , SÁNCHEZ LIDYA B. , MOORE DOROTHY V. , MÜLLER MIKLÓS
Published: July 2005

ABSTRACT. A gene encoding a putative GTP‐specific phosphoenolpyruvate carboxykinase has been cloned and sequenced from the type I amitochondriate protist Giardia intestinalis. The deduced amino acid sequence is related most closely to homologs from hyper‐thermophilic archaebacteria and only more distantly to homologs from Eubacteria and Metazoa. Most enzymes of Giardia core metabolism, however, are related more closely to eubacterial and metazoan homologs. An archaebacterial relationship has been noted previously for the unusual acetyl‐CoA synthetase (ADP‐forming) of this organism. The results suggest that phosphoenolpyruvate carboxykinase and acetyl‐CoA synthetase have been acquired from different sources than most enzymes of Giardia core metabolism.
Phylogenetic Position of the Trichomonad Parasite of Turkeys, Histomonas meleagridis (Smith) Tyzzer, Inferred from Small Subunit rRNA Sequence1
Authors: GERBOD DELPHINE , EDGCOMB VIRGINIA P. , NOËL CHRISTOPHE , ZENNER LIONEL , WINTJENS RENÉ , DELGADO‐VISCOGLIOSI PILAR , HOLDER MICHAEL E. , SOGIN MITCHELL L. , VISCOGLIOSI ERIC
Published: July 2005

ABSTRACT. The phylogenetic position of the trichomonad, Histomonas meleagridis was determined by analysis of small subunit rRNAs. Molecular trees including all identified parabasalid sequences available in data bases were inferred by distance, parsimony, and likelihood methods. All reveal a close relationship between H. meleagridis, and Dientamoeba fragilis. Moreover, small subunil rRNAs of both amoeboid species have a reduced G + C content and increased chain length relative to other parabasalids. Finally, the rRNA genes from H. meleagridis and D. fragilis share a recent common ancestor with Tritrichomonas foetus, which exhibits a more developed cytoskeleton. This indicates that Histomonas and Dientamoeba secondarily lost most of the typical trichomonad cytoskeletal structures and hence, do not represent primitive morphologies. A global phylogeny of parabasalids revealed significant discrepancies with morphology‐based classifications, such as the polyphyly of most of the parabasalid families and classes included in our study.
Riding The Ciliate Cell Cycle—A Thirty‐Five‐Year Prospectivea
Authors: BERGER JAMES D.
Published: July 2005

ABSTRACT. Studies of the ciliate cell cycle have moved from early examination of its biochemistry with heat‐synchronized Tetra‐hymena through descriptive studies of Paramecium using small synchronous cell samples. These studies described what happens during the cell cycle and provided some initial insights into control, especially the idea that there was a point at which cells became committed to division. This early work was followed by an analytical phase in which the same small sample techniques, combined with gene mutations, were used to tease apart some major features of the regulation of cell growth kinetics, including regulation of macronuclear DNA content and regulation of cell size, the control of timing of initiation of macronuclear DNA synthesis, and the control of commitment to division in Paramecium. The availability of new molecular genetic approaches and new means of manipulating cells en masse made it possible to map out some of the basic features of the molecular biology of cell cycle regulation in ciliates. The challenge before us is to move beyond the ‘me‐too‐ism’ of validating the presence of basic molecular regulative machinery underlying the cell cycle in ciliates to a deeper analysis of the role of specific molecules in processes unique to ciliates or to analysis of the role of regulatory molecules in the control of cell process that can be uniquely well studied in ciliates.
The Ultrastructure of Contractile Tubules in the Heliozoon Actinophrys sol and Their Possible Involvement in Rapid Axopodial Contraction
Authors: KINOSHITA EIJI , SHIGENAKA YOSHINOBU , SUZAKI TOSHINOBU
Published: July 2005

ABSTRACT. We employed an improved fixation procedure for electron microscopy using ruthenium red, and found a bundle of contractile tubules inside the axopodia of the heliozoon Actinophrys sol. Upon food uptake, the tubules shorten and transform into a mass of small granules when rapid axopodial contraction occurs, suggesting that these structures are involved in the process of axopodial contraction. The relationship between transformation of the contractile tubules and accompanying disassembly of the axonemal microtubules was studied by examining the ultrastructure of the contractile tubules after disassembly of the microtubules was artificially induced by cold or colchicine treatment. Granulation of the contractile tubules was induced by cold but not by colchicine treatment. During recovery from cold treatment, granular forms of the contractile tubules became re‐elongated and their initial tubular appearance was restored. These results suggest that the contractile tubules in heliozoon axopodia play a role in repetitive cytoplasmic contraction.
Partial Cloning of Putative G‐Proteins Modulating Mechanotransduction in the Ciliate Stentor
Authors: MARINO MICHAEL J. , SHERMAN THOMAS G. , WOOD DAVID C.
Published: July 2005

ABSTRACT. Signal transduction systems known to utilize G‐proteins in higher eukaryotes undoubtedly evolved prior to the development of metazoa. Pharmacological evidence indicates that the ciliates Paramecium, Stentor, and Tetrahymena all utilize signaling systems similar to those found in mammals. However, there has been relatively little direct evidence for the existence of G‐proteins in ciliates. Since highly conserved heterotrimeric G‐proteins form the basis of receptor‐coupled signal transduction systems in a wide variety of metazoa, it is of interest to know if these important signaling molecules were early to evolve and are present and functionally important in a wide variety of unicellular organisms. We have previously shown that mechanotransduction in Stentor is modulated by opiates in a manner that may involve pertussis toxin‐sensitive G‐proteins. Here we utilize drugs known to interact with G‐proteins to further test for the involvement of these important signaling molecules in Stentor mechanotransduction. We present behavioral and electrophysiological data demonstrating that putative G‐proteins in Stentor decrease mechanical sensitivity by modulating the mechanotransduction process. In addition, we report the partial cloning of 4 G‐protein α‐subunits from Stentor. We confirm that these clones are of Stentor origin and are transcribed. Furthermore, we employ antisense oligodeoxynucleotide‐mediated knockout to demonstrate that these ciliate G‐proteins exert a modulatory influence on Stentor behavior, and that a G1/G0‐like clone mediates the inhibitory action of β‐endorphin on mechanotransduction.
Directed Migration of Ascogregarina taiwanensis (Apicomplexa: Lecudinidae) in its Natural Host Aedes albopictus (Diptera: Culicidae)
Authors: Chen Wei‐June , Fan‐Chiang Mei‐Hwei
Published: July 2005

ABSTRACT. Directed migration of trophozoites from the midgut toward the Malpighian tubules is essential for Ascogregarina taiwanensis (Apicomplexa: Lecudinidae) to complete its developmental cycle within the natural host Aedes albopictus. We have obtained a 275‐bp actin cDNA fragment amplified from extracted mRNAs of migrating trophozoites, suggesting the involvement of actin in trophozoite motility. Down‐regulation on the migration of the trophozoite was seen in mosquito larvae fed with cytochalasin D, ML‐7. and BDM, indicating that myosin, in the form of an actomyosin system, may also be involved in driving motility of the trophozoite. The “protruding apparatus” (PA) formed at the anterior end of trophozoites during the migrating stage had significant deposits of actin by immunofluorescent microscopy. Moreover, PA formation was enhanced in response to elevated levels of 20‐hydroxyecdysone (20‐HE) in cultures of alimentary canals in which the trophozite was contained. Thus, 20‐HE may also promote expression of actin and perhaps myosin simultaneously.
Programmed Translational Frameshifting Is Likely Required for Expressions of Genes Encoding Putative Nuclear Protein Kinases of the Ciliate Euplotes octocarinatus
Authors: TAN MING , LIANG AIHUA , BRÜNEN‐NIEWELER CLAUDIA , HECKMANN KLAUS
Published: July 2005

ABSTRACT. Three macronuclear genes encoding putative nuclear protein kinases of the ciliate Euplotes octocarinatus syngen I were isolated and sequenced. All three deduced gene products share significant properties with a group of recently identified nuclear serine/ threonine protein kinases named Ndr. The three predicted proteins contain the twelve conserved catalytic subdomains of protein kinases and 22 near universally‐conserved amino acids residues that are characteristic of serine/threonine protein kinases. In addition, there is an—30 amino acid‐peptide insertion between subdomains VII and VIII that contains a potential nuclear localization signal. Sequence analysis suggests that expression of the Eondr2 gene requires a +1 programmed translational frameshift for its translation. Comparison of the deduced EoNdr2 with other known Ndr protein kinases implies that a +1 ribosomal frameshift occurs at the motif AAATAA.
Phylogenetic Relationships of the Subclass Peritrichia (Oligohymenophorea, Ciliophora) with Emphasis on the Genus Epistylis, Inferred from Small Subunit rRNA Gene Sequences
Authors: MIAO WEI , YU YU‐HE , SHEN YUN‐FEN
Published: July 2005

ABSTRACT. The peritrichs have been recognized as a higher taxon of ciliates since 1968. However, the phylogenetic relationships among them are still unsettled, and their placement within the class Oligohymenophorea has only been supported by the analysis of the small subunit rRNA gene sequence of Opisthonecta henneguyi. DNA was isolated directly from field‐sampled species for PCR, and was used to resolve relationships within the genus Epistylis and to confirm the stability of the placement of peritrichs. Small subunit rRNA gene sequences of Epistylis plicatilis, Epistylis urceolata, Epistylis chrysemydis, Epistylis hentscheli, Epistylis wenrichi, and Vorticella campanula were sequenced and analyzed using both distance‐matrix and maximum‐parsimony methods. In phylogenetic trees, the monophyly of both the genus Epistylis and the subclass Peritrichia was strongly supported, while V. campanula clustered with Vorticella microstoma. The topology in which E. plicatilis and E. hentscheli formed a strongly supported sister clade to E. urceolata, E. chrysemydis, and E. wenrichi was consistent with variations in the thickness of the peristomial lip. We concluded that the peristomial area, especially the peristomial lip, might be the important phylogenetic character within the genus Epistylis.
The Sterol Composition of Trypanosoma cruzi Changes After Growth in Different Culture Media and Results in Different Sensitivity to Digitonin‐Permeabilization
Authors: RODRIGUES CLAUDIA O. , CATISTI ROSANA , UYEMURA SERGIO A. , VERCESI ANIBAL E. , LIRA RENEE , RODRIGUEZ CARLOS , URBINA JULIO A. , DOCAMPO ROBERTO
Published: July 2005

ABSTRACT. Respiration, oxidative phosphorylation, and the corresponding changes in membrane potential (ΔΨ) of Trypanosoma cruzi epimastigotes grown either in liver infusion‐tryptose (LIT) or brain heart infusion (BHI) culture medium were assayed in situ using digitonin to render their plasma membrane permeable to succinate, ADP, safranine O, and other small molecules. When the cells were permeabilized with 64 μM digitonin, a concentration previously used with epimastigotes, the ability of the cells grown in LIT medium to sustain oxidative phosphorylation was demonstrated by the detection of an oligomycin‐sensitive decrease in mitochondrial membrane potential induced by ADP. In contrast, the cells grown in BHI medium were not able to sustain a stable membrane potential and did not respond to ADP addition. Analyses of oxygen consumption by these permeabilized cells indicated that the rate of basal respiration, which was similar in both cell types, was significantly decreased by 64 μM digitonin. Addition of ADP to the permeabilized cells grown in LIT medium promoted an oligomycin‐sensitive transition from resting to phosphorylating respiration in contrast to the cells grown in BHI medium, whose respiration decreased steadily and did not respond either to ADP or CCCP. Titration of the cells grown in BHI medium with different digitonin concentrations indicated that their mitochondria have higher sensitivity to digitonin than those grown in LIT medium. Analysis of the sterol composition of epimastigotes grown in the two different media showed a higher percentage of cholesterol in total and mitochondrial extracts of epimastigotes grown in BHI medium as compared to those grown in LIT medium, suggesting the involvement of this sterol in their increased sensitivity to digitonin‐permeabilization.
Sarcocystis lindsayi n. sp. (Protozoa: Sarcocystidae) from the South American Opossum, Didelphis albiventris from Brazil
Authors: DUBEY J. P. , ROSENTHAL B. M. , SPEER C. A.
Published: July 2005

ABSTRACT. A new species, Sarcocystis lindsayi n. sp., is proposed for a parasite resembling Sarcocystis falcatula. It was obtained from the lungs and muscles of budgerigars (Melopsittacus undulatus) fed sporocysts from a naturally‐infected South American opossum, Didelphis albiventris, from Jaboticabal, Brazil. Sarcocysts of S. lindsayi n. sp. in budgerigars are microscopic, up to 600 μm long and up to 50 μm wide. The cyst wall is up to 2 μm thick. Ultrastructurally, the sarcocyst wall consists of numerous slender villar protrusions (up to 2.0 μm long and up to 0.3 μm wide), each with a stylet at its tip. Schizonts in cell culture divide by endopolygeny leaving a residual body. Sporocysts are ∼ 12 × 7 μm. The parasite is genetically distinct from other organisms that also cycle between opossums and avian species and resemble S. falcatula. Diagnostic genetic variation has been observed in the nuclear large subunit ribosomal RNA gene, the internal transcribed spacer (ITS‐1), and each of two other genetic loci. Although the structure of the sarcocyst wall may not provide sufficient grounds for differential diagnosis, several other attributes including schizont morphology and genetic variation at each of these genetic loci permit identification of S. lindsayi n. sp. Natural intermediate hosts for S. lindsayi n. sp. are not known, and fuller characterization of these and other Sarcocystis species would benefit from experimental avian hosts that are more permissive to the maturation of sarcocysts.
Phylogenetic Position of Sorogena stoianovitchae and Relationships within the Class Colpodea (Ciliophora) Based on SSU rDNA Sequences
Authors: LASEK‐NESSELQUIST ERICA , KATZ LAURA A.
Published: July 2005

ABSTRACT. The ciliate Sorogena stoianovitchae, which can form a multicellular fruiting body, has been classified based upon its ultrastructure and morphology: the oral and somatic infraciliature of S. stoianovitchae most closely resemble those of members of the order Cyrtolophosidida in the class Colpodea. We characterized the small subunit ribosomal DNA (SSU rDNA) gene sequence from S. stoianovitchae and compared this sequence with those from representatives of all ciliate classes. These analyses placed S. stoianovitchae as either sister to members of the class Nassophorea or Colpodea. In an in‐group analysis, including all SSU rDNA sequences from members of the classes Nassophorea and Colpodea and representatives of appropriate outgroups, S. stoianovitchae was always sister to Platyophrya vorax (class Colpodea, order Cyrtolophosidida). However, our analyses failed to support the monophyly ot the class Colpodea. Instead, our data suggest that there are essentially three unresolved clades: (1) the class Nassophorea; (2) Bresslaua vorax, Colpoda inflata, Pseudoplatyophrya nana, and Bursaria truncatella (class Colpodea); and (3) P. vorax and S. stoianovitchae (class Colpodea).
Development of an Acanthamoeba‐specific Reverse Dot‐Blot and the Discovery of a New Ribotype
Authors: CAST REBECCA J.
Published: July 2005

ABSTRACT. Acanthamoeba is a genus of free‐living amoebae, of which some speeies have been found to cause opportunistic infections in humans. The identification of these amoebae in natural and disease samples is based primarily upon morphological features. While these features are more than adequate for identification to the genus level, they are not useful for species‐level identification. This not only leads to difficulty in the diagnosis of infections, but it makes an accurate assessment of the natural distribution of acanthamoebae very difficult to achieve. To improve this situation, a detection method was developed that utilizes both selective polymerase chain reaction amplification and the reverse dot‐blot. Oligonucleotides were designed to be specific for the described ribosomal groups (or ribotypes) of Acanthamoeba, as well as one specific for the genus itself. When this method was used to analyze a series of Acanthamoeba cultures from Pakistan, a new ribotype was identified in addition to the detection of the ubiquitously distributed T4 type.
Spore Ornamentation of Haplosporidium pickfordi Barrow, 1961 (Haplosporidia), a Parasite of Freshwater Snails in Michigan, USA
Authors: BURRESON EUGENE M.
Published: July 2005

ABSTRACT. Spore ornamentation is increasingly recognized as a key character for species differentiation and genus assignment in the phylum Haplosporidia. Unfortunately, spore ornamentation is known for only a small number of described species so it is difficult to assign most species to genera with any confidence. Scanning and transmission electron microscopy were used to determine the presence and morphology of spore ornamentation of Haplosporidium pickfordi collected from the digestive gland of the snail Physella parkeri in Douglas Lake, Michigan. Spores possess filaments that are derived from the spore wall and originate from two separate areas at the posterior end of the spore. When spores are first isolated from host tissue, filaments are fused into a sheet that wraps around the spore, passing under the opercular lid. These filaments gradually unravel when spores are held in water and after about 14 d most filaments project freely from the posterior end of the spore. The number of filaments could not be determined with certainty, but appears to be approximately nine. Filaments are 100 nm in diam. and up to 50 μm in length. The presence of spore wall‐derived filaments confirms the placement of the parasite in the genus Haplosporidium.
Leptotheca sparidarum N. Sp. (Myxosporea: Bivalvulida), a Parasite from Cultured Common Dentex (Dentex dentex L.) and Gilthead Sea Bream (Sparus aurata L.) (Teleostei: Sparidae)
Authors: SITJÀ‐BOBADILLA ARIADNA , ALVAREZ‐PELLITERO PILAR
Published: July 2005

ABSTRACT. A new myxosporean, Leptotheca sparidarum n. sp., is described from the trunk kidney of two sparid fish, Sparus aurata and Dentex dentex, in several culture facilities from the Western Mediterranean coasts. It is distinguished from all the previously described species by spore morphometrics. Spores with two equal polar capsules and one binucleated sporoplasm. Spore measurements from D. dentex were 5–7.1 μ long × 8.8–12.3 μ thick × 5.88–6.18 μ wide; polar capsules 2.6–3.5 μ in diam. Spore measurements from S. aurata were 5.1–8.24 μ long × 9.41–11.76 μ thick; polar capsules 2.4–3.2 μ in diam. No significant differences were detected between either host. Prevalence could reach 21.4% in D. dentex and 19% in some stock of S. aurata. Renal tubules were the typical site of infection, which was also found in ureters and glomeruli, but seldom in the epiepithelial position of the gut. Spores were formed in disporous sporoblasts, and spore maturation seemed to proceed from the host epithelium towards the lumen. Trophozoites were attached to the host epithelial cells of renal tubules by pseudopodial‐like projections, which were inserted into gaps between epithelial cells. Also, cell junctions were observed between primary cells and between neighboring spores.
Phagosome Formation in Paramecium: Roles of Somatic and Oral Cilia and of Solid Particles as Revealed by Video Microscopy
Authors: ISHIDA MASAKI , ALLEN RICHARD D. , FOK AGNES K.
Published: July 2005

ABSTRACT. The roles of somatic and oral cilia and solid particles during digestive vacuole (DV) formation in Paramecium multimicronucleatum were investigated using video‐enhanced and immunofluorescence microscopy. Membrane incorporation into DVs was found to increase linearly with increasing particle concentration. The rate of discoidal vesicle transport to the cytopharynx was not affected by particles, showing that particles are not required for membrane trafficking to the cytopharynx. However, the presence of particles leads to an increased membrane fusion between the cytopharyngeal membrane and the discoidal vesicles. When live cells lost their somatic cilia on the left‐ventral side anterior to the oral region due to deciliation, membrane incorporation into newly formed DVs was strongly inhibited. Using video‐enhanced microscopy, latex beads were seen to be loaded along the quadrulus on the dorsal surface of the buccal cavity, but few beads were seen next to the dorsal and ventral peniculi. Particle sequestration into a pre‐formed nascent digestive vacuole (NDV) was studied in Triton X‐100‐permeabilized cells whose ciliary beating was reactivated by the addition of Mg‐ ATP. Both beat frequency and the percentage of cells containing bead‐labeled NDV were dependent on the Mg‐ATP concentration: the higher the beat frequency, the higher the percentage of cells with a bead‐labeled NDV. These results suggest that ciliary beating is probably the only mechanism required for particle accumulation in the NDV, while a coordinated beating of the somatic cilia on the left‐ventral side anterior to the oral region as well as the quadrulus moves particles into the NDV. The beating of the peniculi may somehow prevent the backward flow of particles out of the NDV.
Tubulins in Trichomonas vaginalis: Molecular Characterization of α‐Tubulin Genes, Posttranslational Modifications, and Homology Modeling of the Tubulin Dimer
Authors: NOÉL CHRISTOPHE , GERBOD DELPHINE , FAST NAOMI. M. , WINTJENS RENÉ , DELGADO‐VISCOGLIOSI PILAR , DOOLITTLE W. FORD , VISCOGLIOSI ERIC
Published: July 2005

ABSTRACT. We have isolated and analysed an α‐tubulin‐encoding gene (atub1) in an early‐diverging eukaryote, Trichomonas vaginalis. The complete atub1 open reading frame included 1,356 bp encoding a polypeptide of 452 amino‐acyl residues. A second α‐ tubulin gene (atub2) was amplified by PCR using primers derived from consensus α‐tubulin amino acid sequences. Both T. vaginalisα‐tubulin sequences showed high identity to those described in other parabasalids (94.4%–97.3%), and exhibited a high degree of similarity to sequences from Metazoa (such as pig brain) and diplomonads (such as Giardia). Despite large evolutionary distances previously observed between trichomonads and mammals, the three‐dimensional model of the T. vaginalis tubulin dimer was very similar to that of pig brain. Possible correlations between α‐tubulin sequences and posttranslational modifications (PTMs) were examined. Our observations corroborated previous data obtained in T. vaginalis using specific anti‐PTMs antibodies. As described in the related species Tritrichomonas mobilensis, microtubules are likely acetylated, non‐tyrosinated, glutamylated, and non‐glycylated in T. vaginalis. Evolutionary considerations concerning the time of appearance of these tubulin PTMs are also discussed since trichomonads are potentially one of the earliest diverging eukaryotic lineages.
Korotnevella hemistylolepis N. Sp. and Korotnevella monacantholepis N. Sp. (Paramoebidae), Two New Scale‐covered Mesohaline Amoebae
Authors: O'KELLY CHARLES J. , PEGLAR MICHAEL T. , BLACK MEGAN N. D. , SAWYER THOMAS K. , NERAD THOMAS A.
Published: July 2005

ABSTRACT. Two new species of KorotnevellaGoodkov, 1988, Korotnevella hemistylolepis n. sp. and Korotnevella monacantholepis n. sp., are described from mesohaline ecosystems. The amoebae are characterized on the basis of light and electron microscopy with special emphasis on the structure of the basket scales, which have species‐specific architecture. The two new species are the second and third ones recovered from environments other than freshwater. In terms of scale morphology they most closely resemble a freshwater species, Korotnevella bulla (Schaeffer, 1926) Goodkov, 1988. Two genus names, DactylamoebaKorotnev, 1880 and KorotnevellaGoodkov, 1988, are in current use. The latter name is preferred, pending rediscovery and characterization of Dactylamoeba elongataKorotnev, 1880, the type species of the genus. Korotnevella species can be divided into three groups on the basis of scale morphology, suggesting that the genus may not be monophyletic. A key to species is provided.
Platyamoeba pseudovannellida N. Sp., a Naked Amoeba With Wide Salt Tolerance Isolated from the Salton Sea, California
Authors: HAUER GWEN , ROGERSON ANDREW , ANDERSON O. ROGER
Published: July 2005

ABSTRACT. A new species of naked amoeba, Platyamoeba pseudovannellida n.sp., is described on the basis of light microscopic and fine structural features. The amoeba was isolated from the Salton Sea, California, from water at a salinity of ca. 44‰. Locomotive amoebae occasionally had a spatulate outline and floating cells had radiating pseudopodia, sometimes with pointed tips. Both these features are reminiscent of the genus Vannella. However, the surface coat (glycocalyx) as revealed by TEM indicates that this is a species of Platyamoeba. Although salinity was not used as a diagnostic feature, this species was found to have remarkable tolerance to fluctuating salinity levels, even when changes were rapid. Amoebae survived over the range 0‰ to 150%c salt and grew within the range 0%c to 138%c salt. The generation time of cells averaged 29 h and was not markedly affected by salt concentration. This is longer than expected for an amoeba of this size and suggests a high energetic cost of coping with salinity changes. The morphology of cells changed with increasing salinity: at 0‰ cells were flattened and active and at the other extreme (138‰) amoebae were wrinkled and domed and cell movement was very slow. At the ultrastructural level, the cytoplasm of cells grown at high salinity (98‰) was considerably denser than that of cells reared at 0‰.
FISH Probes for the Detection of the Parasitic Dinoflagellate Amoebophrya sp. Infecting the Dinoflagellate Akashiwo sanguinea in Chesapeake Bay
Authors: GUNDERSON JOHN H. , GOSS SUSAN H. , COATS D. WAYNE
Published: July 2005

ABSTRACT. A comparison of the small subunit rRNA sequences of a Chesapeake Bay strain of the dinoflagellate Akashiwo sanguinea and the dinoflagellate Amoebophrya sp. parasitizing it revealed several potential target sites that could be used to detect the parasite through in situ hybridization. The fluorescence of probed cells under various conditions of hybridization was measured by using a spot meter on a Nikon UFX‐II camera attachment so that the effect of various hybridization parameters on probe binding could be determined. Probes directed against both the junction between helices 8 and 11 and helix 46 could detect the parasite, although the helix 8/11 probe produced a stronger signal under the conditions tested. The fluorescence of the probed cells increased with increasing hybridization time up to approximately twelve hours. The background fluorescence was lower at the wavelengths used to detect Texas Red than at those used to detect fluorescein, so probed cells were more distinct when Texas Red was used as the label. Cells stored in cold paraformaldehyde for a year still bound the probes. Young stages of the parasite could be seen more readily after in situ hybridization than after protargol impregnation.
Isolation of a Unique Membrane Protein from Naegleria fowleri
Authors: RÉVEILLER FABIENNE L. , SUH SANG‐JIN , SULLIVAN KAREN , CABANES PIERRE‐ANDRÉ , MARCIANO‐CABRAL FRANCINE
Published: July 2005

ABSTRACT. Naegleria fowleri, an amoeboflagellate, is the causative agent of Primary Amoebic Meningoencephalitis, a fulminating disease of the central nervous system. In order to elucidate the mechanisms of pathogenicity of this amoeba, a cDNA expression library was prepared from N. fowleri RNA. A specific protein was found to be expressed from a cDNA clone designated Mp2CL5. Northern blot analysis showed that the Mp2CL5 mRNA was expressed in pathogenic N. fowleri but was not expressed in non‐pathogenic Naegleria species nor in Acanthamoeba. Western blot analysis using anti‐. N fowleri antiserum demonstrated that IPTG‐induced Escherichia coli Mp2CL5 expressed a 23‐kDa recombinant protein. The Mp2CL5 recombinant protein was histidine‐tagged and purified to homogeneity from E. coli. A polyclonal rabbit antiserum was prepared against the purified Mp2CL5 recombinant protein. This antibody was used to further characterize the Mp2CL5 native protein expressed by Nfowleri. Western blot analysis in conjunction with immunofLuorescence microscopy demonstrated the presence of a native protein of 17 kDa on the plasma membrane of N. fowleri trophozoites. The native N. fowleri protein was expressed in the logarithmic phase of trophozoite growth and the production of this protein increased through the stationary phase of growth. Studies are in progress to examine further its role as a virulence factor.
Odd Mating‐type Substances May Work as Precursor Molecules of Even Mating‐type Substances in Paramecium caudatum
Authors: XU XUEHUA , KUMAKURA MICHIHO , KAKU EMI , TAKAHASHI MIHOKO
Published: July 2005

ABSTRACT. Mating‐type substances are key molecules in the sexual recognition of the odd (O) and even (E) complementary mating‐type cells in Paramecium caudatum. Indirect evidence suggested that the substances were proteins and were located on ventral surface cilia. Monoclonal antibodies inhibiting the mating reactivity of the O cells have been obtained. Using these antibodies, we tried to detect antigen molecules as dot‐blot signals. Strong dot‐blot signals of antigens were only detected from the mating reactive cells, but they were not detected from the well‐fed and starved cells without mating reactivity. In addition to identifying the antigen on cilia and cytoplasm of the O cell, the antigen was detected from the cytoplasm of the E cells but never from their cilia. Furthermore, extracts of the E cells induced mating reaction with the living E cells but not with O cells. Thus, the O mating‐type substances exist in the cytoplasm of the E mating‐type cells, supporting strongly the hypothesis that O mating‐type substances are precursor molecules of the E mating‐type substances.
Molecular Cloning and Characterization of a Gene Encoding a 13.1 kDa Antigenic Protein of Naegleria fowleri
Authors: SHIN HO‐JOON , CHO MYUNG‐SOO , JUNG SUK‐YUL , KIM HYUNG‐IL , PARK SUN , KIM HAN‐JIP , IM KYUNG‐IL
Published: July 2005

ABSTRACT. An antigen‐related gene was cloned from a cDNA expression library of Naegleria fowleri by immunoscreening with sera obtained from mice that were either immunized with an amoebic lysate or infected with trophozoites. The coding nucleotide sequence of the cloned gene consisted of 357 bases that were translated into 119 amino acids. This gene was designated as nfal. The predicted amino acid sequence of Nfal protein has two potential glycosylation and three potential phosphorylation sites, and its predicted secondary structure consists of four helices and three corners. The deduced amino acid sequence of Nfal protein shares 43% identity with the myohemerythrin (myoHr) protein from a marine annelid, Nereis diversicolor, including 100% identity in conserved regions and iron‐binding residues. A phylogenetic tree constructed from amino acid sequences placed the N. fowleri Nfal protein outside of a cluster of myoHr proteins from eight invertebrates. A purified recombinant protein that migrated as a 13.1 kDa species in SDS‐PAGE was produced. This recombinant protein exhibited a strong immunoreactivity with infected, immune, and anti‐Nfal sera. In addition. an anti‐Nfal serum reacted with an amoeba lysate in immunoblotting analysis. The present nfal gene encoding the myoHr‐like protein is the first myoHr gene cloned from protozoa, and the Nfal antigen may be useful in diagnostic studies.
An Evaluation of Hsp90 as a Mediator of Cortical Patterning in Tetrahymena
Authors: FRANKEL JOSEPH , WILLIAMS NORMAN E. , NELSEN E. MARLO , KEELING PATRICK J.
Published: July 2005

ABSTRACT. This study asks two questions: 1) whether Hsp90 is involved in the regulation of cortical patterning in Tetrahymena, and 2) if it is, whether specific defects in this regulation can be attributed to functional insufficiency of the Hsp90 molecule. To address question I, we compared the effects of a specific inhibitor of Hsp90, geldanamycin, on population growth and on development of the oral apparatus in two Tetrahymena species, T. pyriformis and T. thermophila. We observed that geldanamycin inhibits population growth in both species at very low concentrations, and that it has far more severe effects on oral patterning in T. pyriformis than in T. thermophila. These effects are parallel to those of high temperature in the same two species, and provide a tentative affirmative answer to the first question. To address question 2, we ascertained the base sequence of the genes that encode the Hsp90 molecules which are induced at high temperatures in both Tetrahymena species, as well as corresponding sequences in Paramecium tetraurelia. Extensive comparative analyses of the deduced amino acid sequences of the Hsp90 molecules of the two Tetrahymena species indicate that on the basis of what we currently know about Hsp90 both proteins are equally likely to be functional. Phylogenetic analyses of Hsp90 amino acid sequences indicate that the two Tetrahymena Hsp90 molecules have undergone a similar number of amino acid substitutions from their most recent common ancestor, with none of these corresponding to any known functionally critical region of the molecule. Thus there is no evidence that the Hsp90 molecule of T. pyriformis is functionally impaired; the flaw in the control of cortical patterning is more likely to be caused by defects in mechanism(s) that mediate the response to Hsp90, as would be expected from the “Hsp90 capacitor” model of Rutherford and Lindquist.
Invasion of Different Cell Types by Sporozoites of Eimeria Species andEffects of Monoclonal Antibody 1209‐C2 on Invasion of Cells by Sporozoitesof Several Apicomplexan Parasites
Authors: AUGUSTINE P. C.
Published: July 2005

ABSTRACT. Sporozoites of avian Eimeria species differed markedly in their ability to invade cells in vitro. Invasion by E. tenella and E. adenoeides was significantly greater in baby hamster kidney (BHK) and chicken cecal cell (CC) cultures than in primary chicken(PCK) or turkey kidney (PTK) cell cultures. Moreover, invasion of BHK cell cultures by E. adenoeides was significantly greater thanthat of other Eimeria species, and invasion by E. acervulina Sporozoites was significantly lower. Monoclonal antibody 1209‐C2 (MAb1209‐C2) reacted by immunofluorescent labeling (IFA) with refractile bodies of Sporozoites of 5 species of Eimeria and Caryosporabigenetica, but not with Sporozoites of Toxoplasma gondii, Hammondia hammondi, or Cryptosporidium parvum, which have no refractilebodies. The MAb also cross‐reacted with formalin‐fixed BHK, CC, turkey cecal (TC) cells, and PTK. Pretreatment of BHK cells withMAb 1209‐C2 significantly reduced invasion of the cells by Sporozoites of E. tenella, E. acervulina, E. meleagrimitis, and C. bigenetica, but did not alter invasion by T. gondii, C. parvum, or H. hammondia. Apparently, reactivity of MAB1209‐C2 with the Sporozoites wasrequired for inhibition of invasion despite the fact that the inhibition resulted from pre‐treatment of the host cell. Conversely, althoughMAb 1209‐C2 also reacted moderately with PTK and TC cells, pre‐treatment of these cell cultures with the MAb did not inhibit invasionby either MAB 1209‐C2‐reactive or ‐nonreactive parasites. Collectively, the data indicated that refractile body antigens of Sporozoitesof Eimeria and Caryospora, which are recognized by MAb 1209‐C2, may function in cellular invasion, but also suggest that cellularinvasion is probably not mediated by interactions between the conserved epitopes in sporozoites and cultured host cells that arerecognized by the MAb.
Pneumocystis carinii f. sp. carinii Synthesizes De Novo Four Homologs of Ubiquinone
Authors: SUL DONGGEUN , KANESHIRO EDNA S.
Published: July 2005

ABSTRACT. Ubiquinone, coenzyme Q, plays a pivotal role in electron transport and is a target for chemotherapy against a number of eukaryotic infectious agents, including Pneumocystis carinii. Coenzyme Q10 was previously identified as the major Ubiquinone homolog in P. carinii isolated and purified from rat lungs; CoQ9 was also present. In contrast, CoQ9 and CoQ8 (but not CoQl0) were detected in the lungs of uninfected rat controls. These observations suggested that the pathogen synthesizes CoQ10, and perhaps CoQ9as well. In the present study, CoQ biosynthesis in P. carinii was examined in greater detail. Radiolabeled mevalonate, a precursor of the CoQ polyprenyl chain, was incorporated in vitro into P. carinii ubiquinones. Incorporation of radiolabeled mevalonate into P. carinii CoQ was not enhanced by treating cells with lovastatin, suggesting that the cells did not transport the drug, or that a lovastatin‐ insensitive pathway for de novo synthesis of isoprenoids may also function in this organism. Radiolabeled precursors of the ring moiety, including shikimic acid, p‐hydroxybenzoic acid, and tyrosine were also incorporated into P. carinii CoQ. Unexpectedly, it was found that not only CoQ9 and CoQ10, but also CoQ7, and CoQ8, were metabolically radiolabeled by all the precursors tested, indicating that the organism synthesizes CoQ7, CoQ8, CoQ9, and CoQ10. Metabolic radiolabeling of ubiquinones in rat lung controls was not detected in experiments using either radioactive mevalonate or p‐hydroxybenzoate. Thus the incorporations measured using purified P. carinii preparations were due to the enzymes of the organism.
Redescription of the Rare Heterotrichid Ciliate, Copemetopus subsalsusVilleneuve‐Brachon, 1940
Authors: AL‐RASHEID KHALED A. S.
Published: July 2005

ABSTRACT. The morphology and infraciliature of the rare heterotrichid ciliate Copemetopus subxalsusVilleneuve‐Brachon, 1940 were studied in live and protargol‐impregnated specimens and also by scanning electron microscopy. It is characterized by a dumbbell‐ shaped macronucleus, a specific dorsal brush cilia, an oblique peristome, and a distinct S‐shaped adoral zone of membranelles equipped with whip‐shaped anterior adoral membranelles.
Comparative Morphology of the Euglenid Pellicle. II. Diversity of Strip Substructure
Authors: LEANDER BRIAN S. , FARMER MARK A.
Published: July 2005

ABSTRACT. The morphological diversity associated with the strip substructure of the euglenid pellicle was examined, and after identifying characters and states, we outlined hypotheses about their evolution. We have attempted to standardize terms necessary for analytical comparisons of strips by providing a glossary and comparing published synonyms. Most of the substructural diversity found in euglenids is demonstrated with 13 representative taxa. Strips are generally composed of two subcomponents: frames and projections. Frames support the basic shape of strips and many can be described as either S‐shaped, plateau‐shaped, M‐shaped, or A‐shaped. Projections branch laterally from the frames, are usually periodic, and can be described as thread‐like structures, an indented plate, tooth‐like structures, and plate‐like structures. The ancestral state included strips that were few in number, flat, and fused. The strips became S‐shaped and disjoined in the lineage leading to most euglenid taxa. These strips became secondarily flattened and fused in one lineage. In some lineages of phototrophs, the strips became increasingly robust. Two strips of different morphology formed the repeating pellicular unit or doublet in four taxa. These doublets evolved convergently at least three times and may provide insights into developmental patterns of the cytoskeleton.