bluuebunny/crossref_metadata_2025 huggingface dataset:
Phylogenetic Analysis of Coccidia Based on 18S rDNA Sequence Comparison Indicates that Isospora Is Most Closely Related to Toxoplasma and Neospora
Authors: Carreno Ramon A. , Schnitzler Beate E. , Jeffries Alex C. , Tenter Astrid M. , Johnson Alan M. , Barta John R.
Published: May 2007

The phylogenetic relationships and taxonomic affinities of coccidia with isosporan‐type oocysts have been unclear as overlapping characters, recently discovered life cycle features, and even recently discovered taxa. continue to be incorporated into biological classifications of the group. We determined the full or partial 18S ribosomal RNA gene sequences of three mammalian Isospora spp., Isospora felis, Isospora ohioensis and Isospora suis, and a Sarcocystis sp. of a rattlesnake, and used these sequences for a phylogenetic analysis of the genus Isospora and the cyst‐forming coccidia. Various alveolate 18S rDNA sequences were aligned and analyzed using maximum parsimony to obtain a phylogenetic hypothesis for the group. The three Isospora spp. were found to be most closely related to Toxoplasma gondii and Neospora caninum. This clade in turn formed the sister group to the Sarcocystis spp. included in the analysis. The results confirm that the genus Isospora does not belong to the family Eimeriidae, but should be classified together with the cyst‐forming coccidia in the family Sarcocystidae. Furthermore, there appear to be two lineages within the Sarcocystidae. One lineage comprises Isospora and the Toxoplasma/Neospora clade which share the characters of having a proliferative phase of development preceding gamogony in the definitive host and an exogenous phase of sporogony. The other lineage comprises the Sarcocystis spp. which have no proliferative phase in the definitive host and an endogenous phase of sporogony.
A Developmentally Eliminated Sequence in the Flanking Region of the Histone H1 Gene in Tetrahymena thermophila Contains Short Repeats
Authors: Huvos Piroska E. , Wu Min , Gorovsky Martin A.
Published: May 2007

In Tetrahymena, as in other ciliated protozoans, a transcriptionally active, “somatic” macronucleus develops from a transcriptionally inactive “germline” micronucleus after conjugation. The process of development involves elimination of germline DNA segments at thousands of locations in the genome. The characterization of one of these segments in Tetrahymena thermophila is described here. This micronucleus‐specific DNA has been identified by comparing the sequence of the corresponding micronuclear and macro‐nuclear regions. The micronucleus‐specific DNA is over 1 kb long, is AT‐rich and has TTT direct repeats at its termini. At one end of the micronuclear sequence there is a 130 bp duplication, and at the other end there are several related repeats of a 13‐mer. Short G‐rich sections are found in the middle of the eliminated DNA, as well as on one side of the rearrangement junction. Short G‐rich segments are also detectable in three previously described micronucleus‐specific sequences. The micronuclear sequence described here is a member of a repeat family. Cross‐hybridizing sequences are also detectable in some other Tetrahymena species. The distribution of cross‐hybridizing sequences among related species is not consistent with the phylogenetic tree.
Isospora thibetana N. Sp. (Apicomplexa, Eimeriidae), a Parasite of the Tibetan Siskin (Serinus thibetanus=Carduelis thibetanus) (Passeriformes, Fringillidae)
Authors: Perrucci Stefania , Rossi Giacomo , Macchioni Glido
Published: May 2007

Tibetan siskins are birds native to the Himalayan region often imported into Italy for commercial purposes. Fecal examination of 45 imported subjects with clinical signs of diarrhoea revealed the presence of a large number of coccidian oocysls. After sporulation, accomplished by mixing feces with 2.5 % (w/v) acqueous K2Cr2O7 at room temperature (22° C ± 1° C), exogenous stages of an Isospora species were revealed. The oocysts of this Isospora are spherical, have a bilayered colorless wall, and average 23.24 μm × 23.05 μm; oocyst residuum and micropyle are absent, while an oval polar granule is rarely present. The elliptical sporocysts average 18.44 μm × 10.97 μm and the Stieda body protrudes slightly from the end of the sporocyst. A spherical sporocyst residuum is present though it sometimes consists of scattered granules. The spindle‐shaped sporozoites average 11.53 μm × 2.86 μm, and have two refractile bodies. The taxonomic position of the tibetan siskin is controversial. Some authors include this species in the genus Serinus, while others include it in the genus Carduelis. The coccidian species isolated from these tibetan siskins was, for this reason. compared with the Isospora species previously described both in the genus Carduelis and in the genus Serinus. As a result of this comparison a new species. Isospora thibetana, was named. In the intestine of dead subjects, oocysts were found only in the ileum where the mucosa was greatly thickened and presented a heavy leucocytic infiltration consisting mainly of lympho‐monocytic cells. A similar infiltration was observed in liver and lungs as well.
Changes in the Fatty Acid Composition of the Marine Ciliated Protozoan Parauronema acutum with Increasing Culture Age and Adaptation to Changing Sodium Chloride Concentrations
Authors: Sul Donggeun , Erwin Joseph A.
Published: May 2007

Changes in the fatty acid composition of the membrane lipids of the marine ciliate. Parauronema acutum were studied in ciliates harvested from early logarithmic, decelerating logarithmic and stationary phase culture. The relative amounts of 18:1 (9) and 18:2 (9, 12) decreases in both the phospholipid and the neutral sphingolipid fractions with increasing culture age. The content of 18:4 (6, 9, 12, 15), 20:5 (5, 8, 11, 14, 17) and 22:6 (4, 7, 10, 13, 16, 19) in these same lipids increases with culture age. While P. acutum was isolated as a marine ciliate and is usually grown in a medium containing 2.8% NaCl concentration, it actually grows well over NaCl concentration of 1% to 3% and will grow suboptimally without added NaCl. NaCl concentrations above 3% are inhibitory, although suboptimal growth occurs at 5% NaCl concentration. Lipids obtained from ciliates grown at either 1.5% or 2.8% NaCl have essentially identical FAME profiles. Lipids obtained from ciliates grown at either higher or lower concentrations of NaCl show marked changes in FAME profile. In both cases 18:2 (9, 12) content greatly increases while the content of 18 and 20 carbon highly unsaturated fatly acids, particularly 22:6 (4, 7, 10, 13, 16, 19), decreases.
Quantitation of Absolute Pneumocystis carinii Nuclear DNA Content. Trophic and Cystic Forms Isolated from Infected Rat Lungs are Haploid Organisms
Authors: Wyder Michael A. , Rasch Ellen M. , Kaneshiro Edna S.
Published: May 2007

The Pneumocystis carinii carinii DNA content in nuclei of trophic forms and cysts (spore cases) containing 2, 4, or 8 intracystic bodies, were compared using quantitative fluorescence image analysis. The nuclear DNA content was found to be lower than the theoretical limits of Feulgen cytophotometry. Several fluorescent DNA dyes provide brighter staining, but these techniques suffer from nonspecific binding to other cellular components, such as RNA. It was demonstrated that the thick glycocalyx surfaces of trophic forms and the cyst walls of P. carinii organisms, as well as the cell wall of S. cerevisiae, bound all fluorescent dyes tested to varying degrees. Hence in this study, measurements were performed on cells in which the outer surfaces of organisms were first removed with lyticase. Two stains that appeared most specific for DNA, DB181 and 4′,6‐diamidino‐2‐phenylindole (DAPI), were used for quantitations; lower deviations of fluorescence intensities were observed with DB181. Haploid wild type Saccharomyces cerevisiae and cdc‐28 temperature‐sensitive mutant cells, accumulated at the restrictive temperature (37° C), were used as quantitative internal standards for estimating the absolute nuclear DNA content of P. carinii. Haploid wild type and mutant nuclei stained with DAPI had the same relative fluorescence intensities. The P. carinii nuclear DNA content of trophic forms and individual intracystic bodies (spores), regardless of life cycle stage, were not different. The mean values obtained were 6.9 and 6.7 fg DNA/nucleus with DB181 and DAPI, respectively (approximately 9.26 and 8.99 Mbp nucleotides, respectively). Since these would include 2C (G‐2 phase) and S‐phase nuclei, a 1C population of nuclei was selected by histogram distributions of DB181‐stained nuclei. Almost all nuclei analyzed in all life cycle stages fell within this population. The 1C mean of 6.55 fg DNA/nucleus (median, 6.62 fg DNA/nucleus) was estimated as representing 8.79 Mbp nucleotides, assuming only A‐T binding of the dye and taking into account the G+C content of S. cerevisiae and P. carinii. A 4C (G‐2‐phase diploid nuclei) population was not detected in histograms of DB181‐ or DAPI‐stained nuclei. The P. carinii nuclear DNA content values obtained in this study were similar to those independently obtained by calculating the total DNA in the organism's chromosomes resolved by electrophoretic techniques. Together, the data on total chromosome numbers and the estimated DNA content of those chromosomes, with our quantitation of nuclear DNA content of different life‐cycle stages demonstrate that P. carinii carinii isolated from infected rat lungs are haploid organisms.
A PCR Screen Identifies a Novel, Unconventional Myosin Heavy Chain Gene (MYO1) in Tetrahymena thermophila
Authors: Garcés Jorge , Gavin R. H.
Published: May 2007

Degenerate primers for two regions of sequence homology in the myosin head domain were used in a polymerase chain reaction screen of Tetrahymena thermophila genomic DNA to amplify a 765 bp fragment that was cloned and sequenced. Based on the presence of conserved, myosin‐specific sequences, the 765 bp PCR product was identified as a fragment of a myosin gene, the first to be discovered in ciliated protozoa and herein referred to as MYO1. An inverse polymerase chain reaction strategy was used to obtain additional sequence data that included the entire head domain of MYO1. Alignment of the predicted amino acid sequence of the MYO1 head domain with known myosin sequences identified the ATP‐binding site, a phosphorylation site, and other myosin‐specific consensus regions. In a northern blot analysis, a 765 bp MYO1‐specific probe detected a 6.6 kb transcript under highly stringent hybridization conditions. Phylogenetic analysis revealed that the predicted protein encoded by MYO1 is not a member of any of the previously defined myosin classes and therefore represents a presumptive new myosin class.
Zymolyase Treatment Exposes p55 Antigen of Pneumocystis carinii
Authors: Broomall Kathleen R. , Morris Randal E. , Walzer Peter D. , Smulian A. George
Published: May 2007

Rats exposed to Pneumocystis carinii mount antibody responses to a broad band migrating on western blot with an apparent molecular weight of 45‐55 kDa. One antigen within this band, designated p55, is uniformly recognized by P. carinii exposed rats. Although the gene encoding the p55 antigen had been previously cloned, the location of this antigen within the organism was unknown. Prior attempts to localize the protein were unsuccessful. A monospecific polyclonal antiserum raised against a carboxyl‐terminai 15‐oligomer peptide yielded specific reactivity with a single 55 kDa band on a western blot of P. carinii. Using this antiserum, little to no reactivity could be detected with P. carinii organisms by immunofluorescence assay (IIFA). However, zymolyase treatment of P. carinii dramatically increased the intensity and proportion of organisms reactive by IFA. Zymolyase, an enzyme with β‐1,3 glucanase activity, has previously been shown to remove the electron dense outer layer of the P. carinii cell wall, exposing an electron lucent layer. Immunoelectron microscopy performed on zymolyase treated organisms showed the majority of labeling occurs within the cell wall.
Verification of Intermediate Hosts in the Life Cycles of Microsporidia by Small Subunit rDNA Sequencing
Authors: Vossbrinck Charles R. , Andreadis Theodore G. , Debrunner‐Vossbrinck Bettina A.
Published: May 2007

Small subunit rDNA sequences were obtained from field‐collected Amblyospora connections (Microsporida: Amblyosporidae) spores isolated from the mosquito, Aedes cantator (Diptera: Culicidae), and from field collected spores isolated from the putative intermediate host, Acanthocyclops vernalis (Copepoda: Cyclopidae). The ribosomal DNA sequences of the spores isolated from the two hosts were identical. These findings corroborate previous laboratory transmission studies and validate the intermediary role of A. vernalis in the life cycle of this microsporidium. These data represent the first comparative sequence analysis of a microsporidium isolated from its definitive and intermediate hosts. The results demonstrate the effectiveness of using rDNA sequence data for screening potential intermediate hosts. Unlike laboratory transmission tests, which can take months or years to complete, this technique can be completed in days and can be performed on a single infected organism.
Heterogeneity and a Coiled Coil Prediction of Trypanosomatid‐Like Flagellar Rod Proteins in Euglena
Authors: Ngǒ Huan M. , Bouck G. Benjamin
Published: May 2007

The emergent flagellum of euglenoids and trypanosomatids contained in addition to microtubules a prominent filamentous structure—the flagellar rod (paraflageliar/paraxonemal rod). Immunoblots and immunofluorescence localization using three antibodies generated against gel‐isolated proteins confirmed previous studies that the Euglena flagellar rod consisted of polypeptides migrating at 66‐, 69‐, and 75‐kD. Immunoblotting after two dimensional gel electrophoresis identified ten or more isoforms of these polypeptides. Differences in migration in acrylamide gels under nonreducing and reducing conditions suggested that the rod proteins contain intramolecular disulfide linkages. Comparative peptide mapping showed that the 66‐. 69‐, and 75‐kD polypeptides were distinct, but related proteins, and also identified a fourth related protein migrating at 64‐kD. Using antibodies against rod proteins, two overlapping cDNAs were isolated and from their sequences the cDNAs were predicted to encode 334 amino acids of the 66‐kD protein: the amino acid sequence had >65% identity to the carboxyl‐terminus of the trypanosomatid flagellar rod proteins. Secondary structural prediction suggested that flagellar rod proteins contain an extended segmented coiled coil stalk and two nonhelical heads. Coiled coil appeared to be an important structural motif in the construction of flagellar rod filaments.
Entamoeba histolytica Contains a β1 Integrin‐like Molecule Similar to Fibronectin Receptors from Eukaryotic Cells
Authors: Talamás‐Rohana Patricia , Hernández‐Ramirez Veronica I. , Perez‐García Javier N. , Ventura‐Juárez Javier
Published: May 2007

Entamoeba histolytica trophozoites do interact with extracellular matrix components in order to invade and finally destroy tissue. An important step in this interaction involves the binding of a 140‐kDa membrane protein that binds to fibronectin. The similarity of this amoebic receptor to fibronectin receptors from higher eukaryotic cells was defined by indirect immunofluorescence, western blot and immunohistochemistry. using polyclonal monospecific antibodies raised against the amoebic protein. These results suggest that lower eukaryotic cells have and use a β1 integrin‐like molecule as well as mechanisms similar to those present in higher eukaryotic cells during interaction with extracellular matrix components.
Introducing Antisense Oligodeoxynucleotides into Paramecium via Electroporation
Authors: Fraga Dean , Yano Junji , Reed Michael W. , Chuang Rosa , Bell Wade , Houten Judith L. Van , Hinrichsen Robert
Published: May 2007

ABSTRACT A method utilizing electroporation to deliver antisense oligodeoxynucleotides into Paramecium tetraurelia has been developed. For these studies antisense oligonucleotides directed to different regions of the calmodulin mRNA were used. It was found that a pulse delivered at 150‐250 V (375‐625 V/cm field strength) for 3.9‐4.2 ms using a 275 μF capacitor with resistance set at 13 Ohms was sufficient to achieve measurable incorporation of fluorescently‐labeled oligodeoxynucleotides in up to 95% of the cells treated. Optimal parameters included using oligodeoxynucleotides of at least 12 bases in length with a 3′ blocking group at a dose of around 10 μM. In addition, multiple oligodeoxynucleotides directed to the same target mRNA resulted in at least a 10‐fold reduction in the dose of oligodeoxynucleotide required to achieve the desired effects. Taken together, these results indicate that the use of antisense oligodeoxynucleotides can be an easy and useful method for linking genes to specific functions in Paramecium tetraurelia. Finally, this report discusses how different 3′ blocking groups and the use of combinations of oligodeoxynucleotides directed to different regions of the same target mRNA can help address concerns about specificity.
The HSP70 Gene Family in Pneumocystis carinii: Molecular and Phylogenetic Characterization of Cytoplasmic Members
Authors: Stedman Timothy T. , Butler Diann R. , Buck Gregory A.
Published: May 2007

ABSTRACT Pneumocystis carinii, a major opportunistic lung pathogen of AIDS patients, is found in a number of mammals and is proposed to be a member of the fungi. In this work, several members of the highly conserved HSP70 multigene family were characterized from rat‐derived P. carinii. Previously, we reported characterization of the ER resident HSP70 homolog known as BiP from prototype (P. c. carinii) and variant (P. c. rattus) strains of the organism. We report here, from P. c. carinii, characterization of Pcsal, an HSP70 homolog that encodes a cognate/stress‐induced HSP70 homolog of the SSA subfamily in Saccharomyces cerevisiae. We also identify from both rat strains and from a human isolate of P. carinii (P.c. hominis), a third set of HSP70 homologs that apparently encode a ribosome‐associated cytoplasmic HSP70 homologous to the S. cerevisiae SSB subfamily. Our data indicate that Pcsal mRNA, like Pcbip mRNA, bears an intron in the 5′ untranslated region, is induced by heat shock, and suggest that this gene undergoes alternative transcription and splicing. The SSB homologs display significant sequence heterogeneity between P. carinii source strains, supporting the genetic divergence and likely speciation of P. carinii isolates within and between host species. Phylogenetic analysis with the PcSAl protein supports inclusion of P. carinii among the higher fungi.
Characterization of Myosin Heavy Chain and Its Gene in Amoeba proteus
Authors: Oh Sang W. , Jeon Kwang W.
Published: May 2007

ABSTRACT Monoclonal antibodies against the myosin heavy chain of Amoeba proteus were obtained and used to localize myosin inside amoebae and to clone cDNAs encoding myosin. Myosin was found throughout the amoeba cytoplasm but was more concentrated in the ectoplasmic regions as determined by indirect immunofluorescence microscopy. In symbiont‐bearing xD amoebae, myosin was also found on the symbiosome membranes, as checked by indirect immunofluorescence microscopy and by immunoelectron microscopy. The open reading frame of a cloned myosin cDNA contained 6,414 nucleotides, coding for a polypeptide of 2,138 amino acids. While the amino‐acid sequence of the globular head region of amoeba's myosin had a high degree of similarity with that of myosins from various organisms, the tail region building a coiled‐coil structure did not show a significant sequence similarity. There appeared to be at least three different isoforms of myosins in amoebae, with closely related amino acids in the globular head region.
A Quantitative Approach to Movement, Displacement, and Mobility of Protozoa
Authors: Ricci Nicola , Barbanera Filippo , Erra Fabrizio
Published: May 2007

ABSTRACT Diffusion theory can completely describe the movement of a ciliate along a track of a certain length (L), travelled in a time (t), and with the extremes lying at a distance D. Three important descriptors of this behavior are: (1) the kinetic index (Ik= L/t), namely the average velocity in μm/s, which expresses the state of the “accelerator” of the ciliate; (2) the geometric index (Ig= D/L) measuring the straightness of the track by a dimensionless number. 0 ≤ Ig≤ 1, which expresses the state of the “steering wheel” and represents a sort of “directional efficiency”; and (3) the displacement rate (Rd= D/t), integrating the first two indices and expressing the combined effect of the “accelerator” and the “steering wheel” of the organism with a unique measure (in μm/s), which defines the average displacement rate or the effectiveness of the track in displacing the organism in space. A weighted estimate of general mobility is given by the mobility rate [Rmo= (R̄d.f)creeping‐ (R̄d.f)swimming], obtained by multiplying the average Rd of the creeping organisms and the average Rd of the swimming organisms by their relative frequencies of occurrence (f), and adding the two products. Values for experimental populations of Oxytricha bifaria (Ciliata, Hypotrichida) maintained at 24, 19, 14, and 9° C demonstrated both the appropriateness and the usefulness of these indices and rates to describe the tracks a posteriori, and to provide measures to reason about their possible adaptive significance.
Actin Gene Sequence from Euglena gracilis
Authors: Petersen‐Mahrt Silja K. , Petersen‐Mahrt Svend K. , Widell Slsanne
Published: May 2007

ABSTRACT The full length coding sequence of the Euglena gracilis actin gene was determined by RT‐PCR of Euglena gracilis mRNA. Conserved regions in the actin amino acid sequence were used as guides for the synthesis of degenerate primers. Sequence was obtained for 1.238 nucleotides, of which 1.131 were coding for 377 amino acids. Sequence comparisons showed a similarity with other actins of 56% to 80%. Even though most of the actin amino acid sequence was conserved, some regions showed high divergence, i.e. the DNase I‐binding loop at the N‐terminal region. The construction of a phylogenetic tree based on actin sequences from different organisms placed Euglena gracilis in a cluster with Trypanosoma brucei and Leishmania major.
The Golden Anniversary of the Society of Protozoologists (1947‐1997)1
Authors: Corliss John O.
Published: May 2007

ABSTRACT The history of the Society of Protozoologists is traced from its birth, half a century ago, to the present time. Emphasis is placed on events of the formative years, since data from the scattered records and memories of those times need to be assembled in one place before they are entirely forgotten or “misremembered.” As is true in the establishment of any new association, the people involved are responsible for its later success. Thus tribute is especially paid to the original founding fathers and the early charter members who worked so hard and so unselfishly to assure the permanence—and long—lasting usefulness‐of their Society in a specialized branch of biology. An obvious value of a new scientific organization lies in its production of a scholarly journal. In the present case, such a publication was launched early, and it rapidly became known worldwide as a protozoological research outlet of the highest quality. The aims and goals of the founders seem to have been well met over the past 50 years, but the international Society of Protozoologists faces new challenges and obligations in the years ahead.
A Comparison of Three Populations of the Ciliate Genus, Paracichlidotherus Grim 1992. New Fish Hosts, and Biogeography; Revised Genus Description
Authors: Grim J. Norman
Published: May 2007

ABSTRACT Two populations of Paracichlidotherus (Ciliophora. Nyctotheridae) were collected from the intestines of the Surgeon‐fishes, Zebrasoma flavescens. and Acanthurus nigricans, from waters around the island of Guam. They were examined after Protargol staining and compared with the type population for 14 morphological characters. Right and left posterior short kinetal rows of very close kinetosomes and apparently fused cilia are described based on light microscopy and scanning electron microscopy. They often appear to be part of a second posterior suture system on each side. From transmission electron microscopic studies, kinetid structures of somatic dikinetids are described and compared for normal and fused cilia. They are similar, but in the latter, a fibril connects adjacent dikinetids. The buccal overture is V shaped at its posterior aspect. The genus is described more fully based on these characteristics.
A Short Internal Eliminated Sequence with Central Conserved Sequences Interrupting the LA‐MSC Gene of the 81 Locus in the Hypotrichous Ciliates Oxytricha fallax and O. trifallax
Authors: Seegmiller Adam , Herrick Glenn
Published: May 2007

ABSTRACT IES‐LA is a short Internal Eliminated Sequence interrupting LA‐MSC, a protein‐coding gene of the 81 locus of Oxytricha fallax and O. trifallax. IES‐LA is precisely excised from the gene during development of the macronucleus. The internal eliminated sequence is bounded by CAAT… AATG, and thereby resembles a TBE1 transposon internal eliminated sequence insertion that is grossly shortened (4.1 kbp to 52‐64 bp), consistent with the hypothesis that short IESs are degenerated ancient transposons. The pattern of sequence conservation between five alleles of IES‐LA shows that it differs from previously characterized classes of ciliate short IESs: while many short IESs have conserved ends and diverged centers, IES‐LA is more conserved in its center and its ends are diverged. This implies a excision mechanism for IES‐LA that is distinct from those for other known Oxytricha IESs.
Epibiotic Bacteria on Several Ciliates from Marine Sediments
Authors: Epstein Slava S. , Bazylinski Dennis A. , Fowle William H.
Published: May 2007

ABSTRACTBacterial epibionts were observed on the surface of the marine sediment ciliateGeleia fossata.Rod‐shaped bacteria, from 2‐10 X103per ciliate, were universally positioned in ciliated grooves, in apparent spatial association with dikinetids. SEM and TEM examination of the ciliates confirmed that a tight affiliation exists between the epibiotic bacteria and ciliate cortex infrastructures. These observations, as well as the distinct bacterial distribution pattern over ciliate surface, suggest that there is a close epibiont/host physiological integration. Epibiotic bacteria were also observed on the surfaces of other sediment ciliates from the generaLoxophyllum, Tracheloraphis, Geleia, Paraspathidium, andCyclidium.These findings indicate that the bacterial/protozoa associations are widespread in the marine benthic environment. The potential benefits for both epibionts and their hosts are discussed.
Structure and Expression of a GroE‐homologous Operon of a Macronucleus‐Specific Symbiont Holospora obtusa of the Ciliate Paramecium caudatum
Authors: Dohra Hideo , Fujishima Masahiro , Ishikawa Hajime
Published: May 2007

ABSTRACT The reproductive form of a macronucleus‐specific symbiont Holospora obtuse, when harbored by the macronucleus of the ciliate Paramecium caudatum, selectively synthesized a 63‐kDa protein which is immunologically related to GroEL, or HSP60, of Escherichia coli. Heat shock treatment of isolated cells of the reproductive and infectious form of the bacterium also induced the synthesis of the GroEL homolog. Immunoblotting showed that the amount of this protein per cell, whether the reproductive or infectious form, is roughly constant. Cloning and sequencing of a gene coding for the GroEL homolog suggested that the protein is 55.2% identical to GroEL of E. coli at the amino acid sequence level, and that the gene is preceded by an open reading frame which encodes a protein 39.6% identical to GroES of E. coli. Northern blot hybridization showed that the GroEL homologous gene is highly expressed in the reproductive form, but only in a trace amount in the intermediate and infectious form. Immunoelectron microscopy revealed that the GroEL homolog is localized in the cytoplasm of the reproductive and infectious form.
Induction of Conjugation by Methyl Cellulose in Paramecium
Authors: Yanagi Akira , Haga Nobuyuki
Published: May 2007

ABSTRACT An improved method has been developed for the induction of selfing conjugation in Paramecium. Methyl cellulose induces selfing conjugation simply and efficiently in all species examined. Induction of conjugation by methyl cellulose was characterized in P. caudatum, where it occurred only in sexually mature, mating reactive cells. Conjugation produced sexual offspring and the time course of nuclear processes was substantially the same as that in natural conjugation between cells of complementary mating types. The method is useful for genetic studies in a wide variety of Paramecium species including P. caudatum, P. tetraurelia, P. multimicronucleatum and P. bursaria.
Sarcocystis dubeyella n. sp. and Sarcocystis phacochoeri n. sp. (Protozoa: Sarcocystidae) from the Warthog (Phacochoerus aethiopicus) in South Africa
Authors: Stolte Manuela , Ooening Klaus , Quandt Sybille , Bengis Roy G. , Bockhardt Ingrid
Published: May 2007

ABSTRACT Sarcocystis dubeyella n. sp. and S. phacochoeri n. sp. from muscle fibers of the skeletal musculature of two warthogs in South Africa are described by light and and electron microscopy. Sarcocystis dubeyella sarcocysts are macroscopic (up to 12 mm long and 1 mm wide), with a parasite‐induced encapsulation of the host muscle fiber in which the plasma membrane of the latter remained unaltered. The sarcocyst wall is characterized by evenly arranged, irregularly semicircular or rectangular villar protrusions (5.0 T. 2.8‐11.0 μm) with indented margins and no specific content. Sarcocystis phacochoeri formed filiform microcysts (up to 4 mm long and 0.13 mm wide). Its cyst wall is provided with tightly packed, molarlike villar protrusions (1.6‐3.3 T. 1.7‐3.3 μm), with smooth margins, hollow on one side, and with longitudinal condensations of the fine granular matrix at various locations in the interior.
Densities and Diversity of Gymnamoebae in Relation to Some Inshore Aquatic Habitats at Bermuda
Authors: Anderson O. Roger
Published: May 2007

ABSTRACT Densities and diversity of gymnamoebae are reported for three sites at Bermuda. Two are marine sites in Mullet Bay, and the third is a shallow pond (Ferry Reach Park), Bermuda. Site 1 (edge of a small island in Mullet Bay) had higher densities of gymnamoebae (28,761/g sediment) than at a disturbed site 2 (17,597/g), a boat mooring. The diversity was higher, however, at site 2 (H = 4.3) compared to site 1 (H = 3.3). The site 2 species were larger including morphotypes categorized as type 1 (e.g. Mayorella and a reticulate amoeba). The brackish inland pond had higher abundances in the sediments (40.590/g) compared to the marine habitats. However, the diversity was lower (H = 2.7) and it was dominated largely by Vannella and Platyamoeba (categorized as morphotype 4). These data are consistent with findings at continental coastal locations in northeastern USA. Pond sediments generally contain higher densities of gymnamoebae than marine coastal sediments with less organic content. The ratio of type 4 to type 1 amoebae in pond samples is higher than those from coastal sites. The data from Bermuda, an open ocean insular site, provide additional zoogeographic evidence for the generality of these patterns of abundance.
Regional Differentiation of Cortical Structures and Their Reorganization during Cell Division in Paramecium trichium
Authors: Takahashi Tadao , Okubo Masa‐Aki , Hosoya Hiroshi
Published: May 2007

We observed the cell surface of Paramecium trichium using three different methods. A non‐dividing paramecium's cell surface consisted of three major regions outside of the oral apparatus: a) an oral groove region, with 2‐cilia‐2‐basal‐body (2C‐2BB) units; b) a posterior region, occupying 1/4 to 1/5 of the cell surface, with 1‐cilium‐l‐basal‐body (1C‐1BB) units; c) the remainder, with l‐cilium‐2‐basal‐body (1C‐2BB) units. Five kinds of region‐specific cortical reorganization occurred prior to cytokinesis: the 2C‐2BB and 1C‐1BB units were not duplicated, while the 1C‐2BB units were reorganized to 2C‐2BB, 1C‐2BB or 1C‐1BB units. These reorganizations of the cell surface progressed from the fission line to the anterior in the prospective anterior daughter cell, and to the posterior in the prospective posterior daughter cell, and bilaterally from the old and also newly developing oral apparatus in both daughter cells. In contrast, the development of cilia and their associated structures in each of the cortical units always progressed from posterior to anterior. The present work also showed that two fission lines began to develop bilaterally from the oral primordium, and then they joined to become a single fission line at the dorsal surface.
Phylogenetic Placement of Trichonympha
Authors: Dacks Joel B. , Redfield Rosemary J.
Published: May 2007

Flagellated protists of the Class Hypermastigida have previously been classified on morphology alone, since no molecular sequences have been available. We have isolated DNA from 350 cells of the hypermastigote Trichonympha, manually collected from the hindgut of Zootermopsis angusticollis, and used this DNA as template for polymerase chain reaction amplification of the small‐subunit ribosomal RNA gene. The DNA sequence of the amplified fragment is closely related to that of a previously‐unidentified gut symbiont from the termite Reticulitermes flavipes, and phylogenetic analysis places both sequences as a sister group to the known trichomonads. in agreement with the morphological classification.
Cinetozona pyriformis n. g., n. sp.: a Relative of the Ciliate Genera Urozona and Cinetochilum (Ciliophora, Scuticociliatida)
Authors: Olmo José L. , Téllez Carmen , Esteban Genoveva F.
Published: May 2007

Cinetozona pyriformis n. g., n. sp. is a very small scuticociliate recently found in a freshwater artificial pond in Madrid, Spain. This new ciliate is here described using silver impregnation techniques. C. pyriformis bears a girdle of cilia near the equator ot the cell, similar to the genus Urozona Schewiakoff, 1889, while the oral structures resemble those in the genus Cinetochilum Perty, 1852. The ciliate's systematic position is discussed, and its inclusion in the family Cinetochilidae is proposed.
Insights on the Diversity within a “Species” of Thalassicolla (Spumellarida) Based on 16S‐like Ribosomal RNA Gene Sequencing
Authors: Zettler Linda A. Amaral , Anderson O. Roger , Caron David A.
Published: May 2007

We compared 16S‐like ribosomal RNA (rRNA) coding regions of samples of the solitary spumellarian radiolarian Thalassicolla nucleata collected from the Sargasso Sea and the Pacific Ocean. Sequences derived from these locations showed variability in both length and base‐pair composition. This level of sequence variability is similar to the degree of variability reported in the literature for species‐ or even genus‐level distinctions. Explanations for our results include multiple alleles for the rRNA gene, or the existence of multiple species of Thalassicolla that are morphologically indistinguishable. The seven existing descriptions of Thalassicolla species, including T. nucleata, are discussed in view of these molecular findings and with reference to our current understanding of the physiology and life cycle of the spumellarian radiolaria.
A Description of Occurrence and Morphology of a New Species of Red‐Water Forming Strombidium (Spirotrichea, Oligotrichia)
Authors: Montagnes David J. S. , Humphrey Elaine
Published: May 2007

We describe a red‐water ciliate, Strombidium lingulum n. sp., collected from a marine fjord in British Columbia (BC), Canada. In August, 1995, red‐brown streaks were observed in the waters of Kyuquot Sound. BC. These streaks were composed of a ciliate population with an abundance in the surface of ˜ 1.5 × 103 cells ml‐1. Density was reduced to < 50 cells ml‐1 below the surface. The bloom persisted for only a few hours; cells were observed for 3‐4 days and were only occasionally observed in the weeks after the bloom. The red waters were speculated to be formed by a combination of downwelling events and an observed phototactic migration of the ciliate. As the ciliate was positively phototactic and pigmented, it may be mixotrophic; it was certainly heteroirophic, as it contained dinoflagellates and small ciliates in food vacuoles. Ciliates were preserved in Lugol's iodine and then both protargol stained and prepared for scanning electron microscopy.
The Small Subunit Ribosomal RNA Gene Sequence of Pleistophora anguillarum and The Use of PCR Primers for Diagnostic Detection of the Parasite
Authors: Hung Hsu‐Wei , Lo Chu‐Fang , Tseng Chieh‐Chih , Peng Shao‐En , Chou Chih‐ Ming , Kou Guang‐Hsiung
Published: May 2007

Using the polymerase chain reaction (PCR) and two primers for conserved regions of the small subunit ribosomal RNA (SSU‐rRNA.) of Microsporidia, a DNA segment about 1,195 base pairs long was amplified from a DNA template prepared from purified spores of the microsporidian species Pleistophora anguillarum. These spores had been isolated from adult eels (Anguilla japonica) with “Beko Disease.” A comparison of sequence data from other microsporidian species showed P. anguillarum SSU‐rRNA to be most similar to Vavraia oncoperae. When juvenile eels were artificially infected with P. anguillarum, enzyme‐linked immunosorbent assay could detect a positive infection only 12 days post‐infection. However, when suitable PCR primers were used, a DNA fragment of about 0.8 kb was detected from these juvenile eels after only 3 days post‐infection. No PCR product was obtained with templates prepared from clinically healthy control animals.
Polar Tube Proteins of Microsporidia of the Family Encephalitozoonidae
Authors: KEOHANE ELAINE M. , ORR GEORGE A. , TAKVORIAN PETER M. , CALI ANN , TANOWITZ HERBERT B. , WITTNER MURRAY , WEISS LOUIS M.
Published: May 2007

ABSTRACT Encephalitozoonidae are microsporidia associated with human infections including hepatitis, encephalitis, conjunctivitis, and disseminated disease. Microsporidia produce a small resistant spore containing a polar tube which serves as a unique vehicle of infection. Polar tube proteins (PTPs) from Encephalitozoon hellem, Encephalitozoon (Septata) intestinalis, and Encephalitozoon cuniculi were purified to homogeneity by HPLC. By SDS‐PAGE, the Mr of E. hellem PTP was 55 kDa, while the Mr of E. intestinalis and E. cuniculi PTP was 45 kDa. Polyclonal rabbit antiserum to these purified PTPs localized to polar filaments by immunogold electron microscopy and immunofluorescence, and demonstrated cross‐reactivity by both immunoblotting and immunogold electron microscopy. These PTPs have similar solubility properties, hydrophobicity, and proline content to a 43‐kDa PTP we have previously purified from Glugea americanus, a fish microsporidium. As the polar tube is critical in the transmission of this organism, further study of PTPs may lead to the development of new therapeutic strategies and diagnostic tests.
Disturbance of the Determination of Germinal and Somatic Nuclei by Heat Shock in Paramecium caudatum
Authors: YANG XIANYU , TAKAHASHI MIHOKO
Published: May 2007

ABSTRACT During conjugation of Paramecium caudatum, nuclear determination occurs soon after the third postzygotic division: one of the four anterior nuclei becomes the micronucleus and the remaining three degenerate, while four posterior nuclei differentiate into macronuclear anlagen. Macronuclear differentiation is supposed to be dependent on a cytoplasmic differentiation factor. In this study, postzygotic cells were subjected to heat shock for 30 min and nuclear changes were observed by staining with carbol fuchsin solution. When heat shock was initiated during the period from metaphase to telophase of the third postzygotic division, cells showed an excess of macronuclear anlagen and were typically amicronucleate. Abnormal nuclear localization around the end of the third (last) postzygotic division may explain the origin of these kinds of cells. A similar phenomenon appeared after treatment with actinomycin D or emetine. Since heat shock did not inhibit macronuclear differentiation but destroyed the formation of micronuclei, some factor(s) probably plays an essential role in nuclear determination, especially in the protection of the micronuclei.
Transformation of Paramecium tetraurelia by Electroporation or Particle Bombardment
Authors: BOILEAU ANDREW J. , KISSMEHL ROLAND , KANABROCKI JOSEPH A. , SAIMI YOSHIRO
Published: May 2007

ABSTRACT Methods for mass transformation of Paramecium tetraurelia were established using plasmids bearing neomycin‐resistance or calmodulin gene fragments. Phenotypic and molecular analyses showed that, although variable, up to 5% transformation can be achieved by electroporation. Concentrations of divalent cations Ca2‐ and Mg2+ in the electroporation medium were crucial for efficient transformation. Strong neomycin‐resistance transformation using bioballistic particle bombardment with gold particles was observed. For both methods, hybridization to transformant DNA revealed plasmid signals consistent with macronuclear transformation and correlated with transformed phenotypes. Complementation of a known calmodulin gene mutation was also achieved by mass transformation. Possible sources of variation and the general utility of these methods are discussed.
Growth and Grazing Rates of the Marine Planktonic Ciliate Strombidinopsis sp. on Red‐Tide and Toxic Dinoflagellates
Authors: JEONG HAE JIN , SHIM JAE HYUNG , LEE CHANG WON , KIM JAE SEONG , KOH SEONG MIN
Published: May 2007

ABSTRACT We investigated growth and grazing rates of Strombidinopsis sp. when feeding on several species of red‐tide and/or toxic dinoflagellates. Strombidinopsis sp. one of the largest aloricate choreotrichs so far reported, grew well on Lingulodinium polyedrum, Gymnodinium sanguineum, Scrippsiella trochoidea, Cochlodinium polykrikoides, and Prorocentrum minimum, but failed to grow on Amphidinium carterae. Specific growth rates of Strombidinopsis sp. increased rapidly with increasing prey density up to ca. 100 ng C ml‐1, but were saturated or increased slightly at higher concentrations. Maximum specific growth rates of Strombidinopsis sp. on various prey species were 1.38 day‐1 for C. polykrikoides, 1.27 for G. sanguineum, 1.06 for P. minimum, 0.83 for L. polyedrum, and 0.67 for S. trochoidea. Threshold prey concentrations (where net growth = 0) were 12–38 ng C ml‐1. Maximum ingestion and clearance rates of Strombidinopsis sp. were 353 ng C grazer‐1 day‐1 and 110 μ, l grazer‐1 h‐1, respectively. Strombidinopsis sp. exhibited higher maximum growth, ingestion, and clearance rates than the mixotrophic dinoflagellate Fragilidium cf. mexicanum or the heterotrophic dinoflagellates Protoperidinium cf. divergens and P. crassipes, when grown on the same prey species. In addition, the sequence of prey species arranged according to growth response of Strombidinopsis sp. differed considerably from those of Fragilidium cf. mexicanum, Protoperidinium cf. divergens, and P. crassipes.
Identification of Trypanosoma cruzi Zymodemes by Kinetoplast DNA Probes
Authors: MONTAMAT ENRIQUE E. , DURAND SANDRA , BOCCO JOSE L. , D'ORO GLORIA M. DE LUCA , BLANCO ANTONIO
Published: May 2007

ABSTRACT Analysis of zymograms of extracts of Trypanosoma cruzi isolated from different hosts in Argentina allowed characterization of 12 zymodemes or “isozymic strains,” only six of which were found in human patients. Two of these six zymodemes (Z1 and Z12) were widely distributed and found in more than 80% of human patients. These two “major natural clones” differed significantly in pathogenic activity. Because the groupings obtained by studying enzymes and kinetoplast DNA (kDNA) were similar, it is possible to identify the zymodeme by analyzing kDNA. A 290‐bp fragment was amplified by PCR using primers for the sequences flanking the hypervariable regions of kDNA minicircles. Labeled probes for this fragment, prepared from Z1 and Z12 reference stocks, hybridized specifically with PCR‐amplified kDNA from parasite stocks, allowing identification of zymodemes.
A Molecular Study of Euglenoid Phylogeny using Small Subunit rDNA
Authors: LINTON ERIC W. , HITTNER DANA , LEWANDOWSKI CAROLE , AULD THERESA , TRIEMER RICHARD E.
Published: May 2007

ABSTRACT The euglenoids are an ancient and extremely diverse lineage of eukaryotic flagellates with unclear relationships among taxa. Synapomorphies for the euglenoids include a surface pellicle and a closed mitosis with a series of separate sub‐spindles. The taxonomy currently in use is inconsistent with the available data and needs revision. Most euglenoid phylogenies are largely intuitive reconstructions based on a limited number of morphological characters. Therefore, we have added molecular characters from the Small Subunit (SSU) rDNA to generate an overall phylogenetic framework for the euglenoids. SSU rDNA sequences from photosynthetic, osmotrophic, and phagotrophic euglenoids were aligned based on secondary structure. Phylogenetic analysis using the conserved areas of the sequence was performed using parsimony, maximum likelihood, and distance methods. Trees derived using different criteria are in agreement. The euglenoids form a distinct monophyletic clade with phagotrophic members diverging prior to the phototrophic and osmotrophic members. Among photosynthetic members, the biflagellate form diverged prior to the uniflagellate form. Additionally, the genus Euglena appears to be paraphyletic, with osmotrophic taxa, such as Astasia and Khawkinea, diverging independently within the clade containing the photosynthetic genus Euglena.
Rediscovery of Paramecium nephridiatum Gelei, 1925 and its Characteristics
Authors: FOKIN SERGEI I. , STOECK THORSTEN , SCHMIDT HELMUT J.
Published: May 2007

Paramecium nephridiatum Gelei. 1925, was rediscovered. It is a euryhaline brackish‐water species that morphologically resembles Paramecium woodruffi. but with multiple contractile vacuole pores. The general morphology, morphometry. and random amplified polymorphic DNA (RAPD) fingerprint patterns are presented for a number of the stocks collected around the world.
The Role of Iron In Protozoan and Fungal Infectious Diseases
Authors: WEINBERG EUGENE D.
Published: May 2007

ABSTRACT. To survive and replicate in vertebrate hosts, protozoan and fungal invaders must be capable of securing host iron. Successful pathogens obtain the metal from either extraction of heme, binding of siderophilins. binding of siderophores, and/or iron pools within host cells. the actual strategy can vary with the availability of iron in the particular host milieu. As a corollary, hosts have developed an elaborate iron withholding defense system. Conditions that can compromise the system as well as procedures that can strengthen it are reviewed.
Description of Opisthonecta Matiensis N. Sp. (Protozoa, Ciliophora), A New Peritrich Ciliate From Wastewater
Authors: MARTÍN‐CERECEDA MERCEDES , SERRANO SUSANA , GUINEA ALMUDENA
Published: May 2007

ABSTRACT. Opisthonecta matiensis n. sp. was isolated from the inlet water of a wastewater treatment plant near Madrid. Spain, and studied in vivo, with silver methods, and using electronic and indirect immunofluorescence microscopy. This new species shows an amphora‐like cell shape and has a size of 45‐73 μm (x̄ 58.2) × 25‐40 μm (x̄ 31.3). the oral infraciliature is formed by one haplokinety, three polykineties, and a short row of kinetosomes (epistomial membrane). the aboral infraciliature is made up of the trochal band and the scopula. From the trochal band arise three fibrillar systems: oral fibers, aboral fibers, and oblique fibers. the myoneme system is composed of a delicate peristomial ring, longitudinal branched fibers that reach the trochal band and of radial fibers extending from the scopula to the trochal band. the silverline system consists of an average of 147 lines. This new species is separated from other known forms by its smaller size, the presence of one single vacuole, and its higher number of silverlines.