bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microtubular Systems of Paramecium in Division: Pattern of Cytospindle Assembly
Authors: DELGADO PILAR , ROMERO M. ROSARIO , TORRES ANTONIO 
Published: May 2007

ABSTRACTThe pattern of cytospindle assembly and the modifications of the microtubular cytoplasmic network during division of Paramecium are studied by means of indirect immunofluorescence. The assembly of cytospindle starts at two independent areas placed respectively around the proter's and opisthe's buccal overture. The moment of the microtubule bundles’appearance depends on their distance from the buccal opening, with those closest appearing 1st. The existence of microtubule organizing centers that act transiently during division of Paramecium is discussed.
Ultrastructure of Minchinia Sp. Spores from Shipworms (Teredo Spp.) in the Western North Atlantic, with a Discussion of Taxonomy of the Haplosporidiidae
Authors: McGOVERN ELIZABETH R. , BURRESON EUGENE M. 
Published: May 2007

ABSTRACTElectron microscopy of haplosporidan spores from Teredo navalis and T. furcifera revealed 4 distinct membrane‐bound extensions, 1 apical extension opposite the opercular hinge, 1 terminal and 2 opposing lateral extensions. These extensions were not continuous with the spore wall, but contained microtubule‐like structures and degrading epispore cytoplasm. No other known species in the family Haplosporidiidae is characterized by spores possessing four epispore extensions. There are currently two genera in this family, Minchinia and Haplosporidium. The genus Minchinia includes spores such as those of M. chitonis which bear two epispore cytoplasm extensions. Spores of the genus Haplosporidium have been characterized by spore wall derived filaments. A 3rd group of haplosporidan species with spores ornamented by wrappings have traditionally also been assigned to the genus Haplosporidium. Based on the presence of epispore cytoplasm extensions rather than spore wall filaments, the haplosporidan of Teredo spp. can be placed in the genus Minchinia.
Nutritional Studies on Acanthamoeba culbertsoni and Development of Chemically Defined Medium
Authors: SHUKLA O. P. , KAUL S. M. , MEHLOTRA R. K. 
Published: May 2007

ABSTRACTA chemically defined medium containing 11 amino acids, 3 vitamins, 6 inorganic salts and glucose, yielding maximum cell densities of 1.5‐2.5 × 107 cells/ml, has been developed for Acanthamoeba culbertsoni with a mean generation time (MGT) of 10 h. A medium containing six amino acids viz. arginine, methionine, leucine, isoleucine, valine and glycine along with other components could also support good albeit slower growth (MGT 27 h) of the amoeba. Acetate did not serve as a suitable carbon/energy source for A. culbertsoni. This organism bears close resemblance in its nutritional requirements to other Acanthamoeba especially A. polyphaga.
Conjugation Involving Dividing Cells of Tetrahymena thermophila
Authors: BLILEY MARY ANN , BELL CRAIG T. VAN 
Published: May 2007

ABSTRACTFeulgen‐stained preparations of mixtures of starved Tetrahymena thermophila cells of complementary mating types have revealed an atypical form of conjugation involving cells which have completed the nuclear events of cell division, but have not undergone cytokinesis. Both micronuclei in the dividing cells are induced to undergo meiosis, but in 21 of 23 cases, the anterior micronucleus was activated 1st, suggesting that the meiotic inducer is synthesized near the mating junction and diffuses posteriad. Despite the induction of two micronuclei, “triad” conjugants appear to regulate nuclear events so as to produce a normal outcome.
Ultrastructural Evidence for Bacterial Incorporation and Myxotrophy in the Photosynthetic Cryptomonad Chroomonas Pochmanni Huber‐Pestalozzi (Chyptomonadida)
Authors: KUGRENS PAUL , LEE ROBERT E. 
Published: May 2007

ABSTRACTUltrastructural evidence indicates that bacteria are routinely incorporated into the CellsChroomonas Pochmanni. This strain has a specialized vacuole for capturing bacteria and retaining them in this vacuole. Bacteria appear to be drawn into the vacuole through a small opening which becomes occluded by membranes, completely enclosing the Bacteria. On rare occasions, ohter membrane components and intact ejectisomes also become incorporated into this vacuole. Bacteria‐like remnants in small vesicles, in other locations in the cell, suggest that bacteria are digested in these vesicles.
Changes in the Shape of Leishmania major Promastigotes in Response to Hexoses, Proline, and Hypo‐osmotic Stress
Authors: DARLING HOMAS N. , BLUM JOSEPH 
Published: May 2007

ABSTRACTLeishmania major promastigotes in late‐log phase are generally long and slender, and remain so during a 1 h incubation in buffer without exogenous substrate. When glucose, 2‐deoxyglucose, fructose, mannose, or proline are added, the cells become shorter and more rounded. The shape change in response to glucose is complete within 20 min and is reversible upon incubating the cells without substrate. Galactose, 3‐O‐methylglucose, 6‐deoxyglucose, sucrose, maltose, ribose, glycerol, alanine, glutamate or aspartate do not cause the shape change. Decreasing the osmolarity of the medium causes a rounding of the cells similar to that observed in the presence of glucose, and increasing the osmolarity inhibits the shape change in response to glucose. Inhibitors of glucose transport and 2nd messenger analogs do not affect the shape change.
Leishmania donovani: A Chemically Defined Medium Suitable for Cultivation and Cloning of Promastigotes and Transformation of Amastigotes to Promastigotes
Authors: KAR KALIPADA , MUKERJI KRISHNA , NASKAR KSHUDIRAM , BHATTACHARYA AMAL , GHOSH DILIP KUMAR 
Published: May 2007

ABSTRACTA chemically defined medium using commercially available α‐MEM supplemented with HEPES, L‐glutamine, D‐glucose, folic acid, D‐biotin and adenine supports the luxuriant growth and propagation of Leishmania donovani promastigotes. A peak parasite population of about 7.0 × 107/ml at stationary phase and a population doubling time of 11.4 h for high‐subpassage promastigotes were obtained. The medium was suitable for transformation of isolated amastigotes from infected hamster spleen. Promastigotes could be detected by culturing kala‐azar patients’bone‐marrow aspirate or spleen puncture material in this medium. Four out of six freshly transformed isolates gradually adapted and grew well in this medium. Macroscopic colonies appeared on agar plates prepared with the medium within 16–20 days after inoculation. The cloning efficiency was increased about five‐fold by glycerol supplementation.
On the Cytology and Taxonomic Position of Nudispora biformis N. G., N. Sp. (Microspora, Thelohaniidae), a Microsporidian Parasite of the Dragon Fly Coenagrion hastulatum in Sweden
Authors: LARSSON J. I.RONNY 
Published: May 2007

ABSTRACTThe microsporidium Nudispora biformis n. g., n. sp., a parasite of a larva of the damsel fly Coenagrion hastulatum in Sweden, is described based on light microscopic and ultrastructural characteristics. Merogonial stages and sporonts are diplokaryotic. Sporogony comprises meiotic and mitotic divisions, and finally eight monokaryotic sporoblasts are released from a lobed plasmodium. Sporophorous vesicles are not formed. The monokaryotic spores are oval, measuring 1.4–1.8 × 2.8–3.4 μm in living condition. The thick spore wall has a layered exospore, with a median double‐layer. The polaroplast has two lamellar parts, with the closest packed lamellae anteriorly. The isofilar polar filament is arranged in 6 (to 7) coils in the posterior half of the spore. Laminar and tubular extracellular material of exospore construction is present in the proximity of sporogonial stages. In addition to normal spores teratological spores are produced. The microsporidium is compared to the microsporidia of the Odonata; its possible relations to the genus Pseudothelohania and to the Thelohania‐like microsporidia are discussed. The new genus is provisionally included in the family Thelohaniidae.
Buccal and Somatic Infraciliature of Lagynus elegans (Engelmann, 1862) Quennersted, 1867 (Ciliophora, Prostomatea): Remarks on its Systematic Position
Authors: SOLA ANA. I. , GUINEA ALMUDENA , LONGAS JOSE F. , FERNANDEZ‐GALIANO DIMAS 
Published: May 2007

ABSTRACTThe somatic and buccal infraciliature of Lagynus elegans are described, and aspects of its division and conjugation are reported. Its somatic infraciliature is made up of 37–46 meridianal kineties composed of isolated kinetosomes that have thick and long kinetodesmal fibers. In the anterior zone of the cell, the circumoral infraciliature can be observed: it is composed of short, slightly oblique kinetal segments, which are formed of three kinetosomes each. The brosse of this species consists of 3 or 4 groups that possess 4 to 6 ciliated kinetosomes each; these kinetosomes lack kinetodesmal fibers. On the apical pole of the cell, surrounding the oral opening, a crown of nematodesmata is observed; these nematodesmata are connected to each other by a fibrillar structure. Taking into account these features, we propose that this genus be transferred from the order Prostomatida to a new family, Lagynidae, of the order Prorodontida.
Constancy of Adenine Methylation in Tetrahymena Macronuclear DNA
Authors: KARRER KATHLEEN M. , STEIN‐GAVENS SUSAN 
Published: May 2007

ABSTRACT. Macronuclear DNA from Tetrahymena was examined in order to determine whether the pattern of adenine methylation changed with the transcriptional activity of nearby genes. The DNA from growing, starved and conjugating cells was digested with six restriction enzymes which are sensitive to methylation of adenine within their recognition site. Southern blots of the restricted DNAs were probed with seven cDNA clones and one genomic clone which are homologous to polyA+ RNAs, whose transcriptional activity varies with the physiological state of the cell. One of the cDNA clones, BC11, had not been described previously. It hybridized to a 1.3kb transcript which was present in populations of starved and conjugating, but not in growing cells. On Southern blots of genomic DNA it hybridized to a complex pattern of bands which was highly polymorphic between the DNAs of closely related strains.It was estimated that between 137 and 272 sites were assayed for changes in methylation, including at least 27 sites which were known to be methylated. No differences were seen in the size of restriction fragments from cells in different physiological states. The data suggested that the methylation pattern, which is determined during macronuclear development, does not vary with the physiological state of the cell.
Uronychia transfuga (O. F. Müller, 1786) Stein, 1859 (Ciliophora, Hypotrichia, Uronychiidae): Cortical Structure and Morphogenesis during Division
Authors: HILL BRUCE F. 
Published: May 2007

ABSTRACTMorphogenesis of cell division was investigated in Uronychia transfuga utilizing both light microscopy of living and stained specimens and SEM of preserved specimens. The cortical morphogenetic pattern of Uronychia is similar in several respects to that of the members of the family Euplotidae. These features include: the de novo development of the opisthe oral primordium in a subcortical pouch; the development of frontoventral and transverse cirri for both the proter and opisthe from 5 cirral primordia that form de novo within a single latitudinal developmental zone; and the absence of right marginal cirri. The members of the genus Uronychia also show a number of unique characteristics: development of a proter oral primordium that causes partial replacement of the parental adoral zone of oral polykinetids during development of the proter; a large oral membrane that is divided into a right and left component; large caudal cirri that bend to the left; and dorsal kineties comprised of closely set paired‐kinetosome kinetids. When compared to the other euplotid‐like ciliates, these unique features support the placement of the genus Uronychia in a separate family, Uronychiidae.
Effect of Extracellular Ions on Motility and Cell Entry in Toxoplasma gondii
Authors: ENDO TAKURO , YAGITA KENJI 
Published: May 2007

ABSTRACTToxoplasma gondii tachyzoites were quiescent in mouse peritoneal fluid or in K2SO4 buffer at pH 8.2. They became consistently motile when K+ was replaced by other monovalent or divalent cations at a constant pH (pH = 8.2). They also became motile when Cl− was substituted for SO42‐. Nitrate or SCN−, can also be substituted for Cl− to a certain extent. Tachyzoites showed independent movement for more than 15 min in KCl, and for about 5 min in the other buffers at pH 8.2 after which they were exhausted and stopped. These tachyzoites could not then be further stimulated to motility by renewal of the suspension buffer. Infection of monolayer cells was demonstrated only with parasites which were motile during inoculation. The highest infectivity was thus obtained either with freshly collected tachyzoites or with those preincubated in K2SO4 buffer for 30 min at 37° C at alkaline pH and thus not yet exhausted for motility. Approximately 34 to 38% of these latter organisms were seen to enter cells when they were inoculated into cultures immediately after being resuspended in MEM for 30 min at 37° C. Conversely, those whose motility had been exhausted by the preincubation in buffers other than K2SO4, pH 8.2 could not enter monolayer cells. Additionally, parasites were unable to enter cells when inoculated into cultures in K2SO4 buffer at alkaline pH; instead they remained quiescent on the surface of the monolayer cells, suggesting that Toxoplasma enters the host cells by active invasion.
Infraciliature, Morphogenesis and Life Cycle of Endosphaera terebrans (Suctoria, Tokophridae)
Authors: ESTEBAN GENOVEVA , TÉLLEZ CARMEN , MUÑOZ AMPARO 
Published: May 2007

The morphology, infraciliature, and life cycle of Endosphaera terebrans, a suctorian endocommensal of peritrichs, have been studied with the aid of silver impregnation.The life cycle of Endosphaera terebrans begins with infection of the host cell by a small larva. The swarmer has a pointed needle‐like cellular projection and two rings of cilia. The swarmer penetrates the peritrich, loses the cilia, and then matures into an adult. The infraciliature of the adult form has four rows of barren kinetosomes that lack kinetodesmal fibers. By endogenous budding, a migratory larva is produced that leaves the host cell through the peristomial disc and that can infect other peritrichs.
Inhibition of the Spore Polar Filament Extrusion of the Microsporidium, Encephalitozoon hellem, Isolated from an AIDS Patient1
Authors: LEITCH GORDON J. , HE QING , WALLACE SARA , VISVESVARA GOVINDA S. 
Published: May 2007

ABSTRACTSpores of the microsporidian parasitic protozoan Encephalitozoon hellem were purified and incubated at 37° C in a solution with an electrolyte composition similar to that of mammalian extracellular fluid, and in solution in which the calcium had been replaced with 0.2 mM EGTA. Polar filament extrusion (germination) was monitored by both scanning electron microscopy and light microscopy. Germination was pH‐dependent, with optima at pH 7.4 and 9.5, and was significantly greater in the presence of medium calcium. Hydrogen peroxide caused a concentration‐dependent increase in germination that was also reduced in a calcium‐free medium. Four agents were found to inhibit spontaneous and H2O2‐stimulated polar filament extrusion: the microfilament disrupter, cytochalasin D; the microtubule disrupter, demecolcine; the calcium channel blocker, nifedipine; and the antifungal agent, itraconazole. These results are consistent with the existence of a calcium‐channel‐mediated step, and requirements for an F‐actin‐ and for a tubulin‐containing element in the germination process of the spore of this parasite. Nifedipine, cytochalasin D and itraconazole all have different sites of action and were therefore able to potentiate one another when used in paired combination to inhibit germination.
Acanthamoeba stevensoni N. Sp. (Protozoa: Amoebida) from Sewage‐Contaminated Shellfish Beds in Raritan Bay, New York
Authors: SAWYER THOMAS K. , NERAD THOMAS A. , LEWIS EARL J. , McLAUGHLIN SHAWN M. 
Published: May 2007

ABSTRACTMarine sediments from 12 shallow water stations in Raritan Bay, New York were tested for the presence of Acanthamoeba. Eight stations were positive for one or more species of Acanthamoeba, A. castellanii, A. comandoni, A. hatchetti, A. lenticulata, A. polyphaga, A. rhysodes, and Acanthamoeba spp. Isolates that grew at 38–40° C were found at four stations (A. comandoni, A. lenticulata, and two unidentified strains). The two unknown strains were characterized on the basis of morphological features, isoenzyme profiles, and mouse pathogenicity tests. One of the two strains was determined to be a new species and is designated herein as Acanthamoeba stevensoni n. sp., ATCC 50388. Mature cysts were most similar to those of morphological Group II of Pussard & Pons (1977). Acanthamoeba stevensoni n. sp. was isolated from inshore coastal sediments where seawater ranged from 20–30%‰ (ppt.). The sediments supported commercially valuable populations of hard clams, Mercenaria mercenaria, that required depuration prior to sale because of contamination by sewage‐associated bacteria.
Development ofTrypanosoma (M.) theileriin Tabanids
Authors: BÖSE REINHARD , HEISTER NICOLIN C. 
Published: May 2007

ABSTRACTThus far the life cycle ofTrypanosoma (Megatrypanum) theilerihas not been studied. We collected tabanids during the mass hatching, when only few tabanids are infected with trypanosomes. Tabanids were caught immediately after attacking a bait cow to serve as controls or after they had been allowed to engorge on theTrypanosoma (M.) theileri‐infected cow. Tabanids were kept in the laboratory and used to study the developmental cycle ofT. (M.) theileriin the tabanid gut. From day 1 to day 10 the presumably unfed controls and the engorged tabanids were dissected and cytological smears made from the mid‐ and hindgut. In total 2.6% (1/38) of the controls and 39% (23/59) of the engorged tabanids were positive for trypanosomes in the 1991 season. From day 1 to day 4 after engorgement trypanosomes were found in the midgut. Epimastigotes with a length of 29 μm on day 1 after infection multiplied by inequal division to form smaller epimastigotes of 26 μm on day 3. On day 4 morphologically indistinguishable trypanosomes of 21 μm total length were found in both mid‐ and hindgut. From day 5 to day 10 trypanosomes were found only in the hindgut in which the transformation to metacyclics was demonstrated, i.e. epimastigotes transformed to amastigote stages of 5 μm in total length.
Serotypic Variation Among Isolates of Ichthyophthirius multifiliis Based on Immobilization
Authors: DICKERSON HARRY W. , CLARK THEODORE G. , LEFF ADAM A. 
Published: May 2007

ABSTRACTEfforts have been made to determine whether surface antigens could be used as biochemical markers to define strain differences in the parasitic ciliate Ichthyophthirius multifiliis. In previous studies, a wild‐type isolate designated G1 was found to have surface proteins analogous to the immobilization antigens of Paramecium and Tetrahymena; rabbit antiserum against this strain immobilizes homologous cells in vitro. It has now been shown for two additional Ichthyophthirius isolates (designated G1.1 and G2) that immobilization antigens are both present and serologically distinct. Proteins of similar size, which cross‐react in Western blots with rabbit antisera against immobilization antigens of the G1 strain, are nevertheless found in the G1.1 and G2 isolates. As shown by Southern blotting analysis, the G1.1 and G2 strains also contain genomic DNA sequences which hybridize with an immobilization antigen cDNA from G1 when probed under conditions of reduced stringency. The serotypic differences in immobilization between I. multifiliis isolates appear to be stable over time and provide a means of discriminating strains. In addition to providing a basis for comparative studies, the work described here has implications for the development of vaccines against this important fish parasite.
Purification and Characterization of Isocitrate Lyase from Ethanol‐grown Euglena gracilis
Authors: ONO KOUKI , OKIHASHI MASAHIRO , INUI HIROSHI , MIYATAKE KAZUTAKA , KITAOKA SHOZABURO , NAKANO YOSHIHISA 
Published: May 2007

ABSTRACTIsocitrate lyase was purified to homogeneity from ethanol‐grown Euglena gracilis. The specific activity was 0.26 μmol/min/mg protein. The molecular mass of the enzyme was calculated to be 380 kDa by gel filtration on a Superose 6 column. The subunit molecular mass of the enzyme was 116 kDa as determined by SDS‐polyacrylamide gel electrophoresis. These results showed that the native form of this enzyme was a trimer composed of three identical subunits. The pH optimum for cleavage and condensation reactions was 6.5 and 7.0, respectively. The Km values for isocitrate, glyoxylate and succinate were 3.8, 1.3 and 7.7 mM, respectively. Isocitrate lyase absolutely required Mg for enzymatic activity. This is the first report of the purification of isocitrate lyase to homogeneity from Euglena gracilis.
The Salient Features of Five Marine Ciliates in the Class Spirotrichea (Oligotrichia), with Notes on their Culturing and Behaviour
Authors: MONTAGNES DAVID J. S. , TAYLOR F. J. R. 
Published: May 2007

ABSTRACTDescriptive information is provided for five ciliates collected from marine coastal British Columbian surface waters. In this paper we identify three new species, Strobilidium neptuni n. sp., Strobilidium veniliae n. sp., and Strombidinopsis multiauris n. sp.; provide a new name and description for one previously described species, Strombidium siculum nom. nov. and provide more taxonomic data for Strombidinopsis cheshiri Snyder and Ohman, 1991.
Chilodonella spp. at Four Fish Farms in Northern Finland
Authors: RINTAMÄKI PÄIVI , TORPSTRÖM HEIKKI , BLOIGU AINI 
Published: May 2007

ABSTRACTA total of 4.1% infestation with Chilodonella spp. was found among fish studied in 144 tanks in 1987–1989, representing 14.0% of the tanks in which fish are reared at four salmonid farms in northern Finland. Two species were found, C. hexasticha and C. piscicola, and both occurred on salmon (Salmo salar L.), sea trout [S. trutta m. trutta (L.)] and brown trout [S. t. m. lacustris (L.)]. Variability was observed in the length and width of the C. piscicola specimens and the number of ciliary rows or kineties. Large specimens which had more kinetics than average for C. piscicola were found mainly on the skin of salmon aged 1–2 years. The number of kinetics in the right ciliary band was found in stepwise logistic regression analysis to be of importance when typing C. piscicola specimens. Fingerlings were found to be more susceptible to Chilodonella infestation than older fish, and mortality varied in the range 2–10% in the course of the epizootics in the three fish species. Most mortality cases were caused by C. hexasticha, occurring mainly on the gills of the fish. Chilodonella piscicola was most often found in salmon and occurred at lower water temperatures than C. hexasticha (mean water temperature when found for the first time being 13° C and 16° C, respectively).