bluuebunny/crossref_metadata_2025_split huggingface dataset:
Guidelines for the Description of New Species of Lower Trypanosomatids1
Authors: WALLACE FRANKLIN G. , CAMARGO E. PLESSMANN , McGHEE R. BARCLAY , ROITMAN ISAAC 
Published: May 2007

ABSTRACTMorphological, cultural, and biochemical criteria that have been used in describing lower trypanosomatids, genera Blastocrithidia, Crithidia, Leptomonas, Herpetomonas, Rhynchoidomonas, and Phytomonas are reviewed. Kinetoplast structure, carbohydrate utilization, electrophoretic mobilities of isoenzymes, and kDNA fingerprinting are among the recommended criteria for species differentiation. Temperature, pH, and osmolarity tolerance are useful growth parameters. Generic placement may be assisted by the determination of nitrogenous excretion products and ornithine‐arginine cycle enzymes.
In Vitro Response of Blastocystis hominis to Antiprotozoal Drugs
Authors: ZIERDT CHARLES H. , SWAN JUDITH C. , HOSSEINI JEANETTE 
Published: May 2007

ABSTRACTTen antiprotozoal drugs were tested in vitro against four axenic strains of the intestinal parasite Blastocystis hominis. Inhibitory drugs in order of effectiveness were emetine, metronidazole, furazolidone, trimethoprim sulfamethoxazole, 5‐chloro‐8‐hydroxy‐7‐iodo‐quinoline (Entero‐Vioform), and pentamidine. Moderately inhibitory were two quinolines other than iodochlorhydroxquin. These were chloroquine and 5, 7‐diiodo‐8‐hydroxy‐quinoline(Floraquin). Diloxanide furoate was not inhibitory. Paromomycin and other antibiotics were not inhibitory. Entero‐Vioform and metronidazole have been effective in human and higher primate diarrhea caused by B. hominis.
Inhibition of Growth and of Thymidine Incorporation into DNA in Tetrahymena by Chlorpromazine, Pimozide and Penfluridol1
Authors: KEEGAN FRANK P. , BLUM JACOB J. 
Published: May 2007

ABSTRACTThe antipsychotic drugs chlorpromazine, pimozide, and penfluridol caused a 50% inhibition of growth of Tetrahymena at concentrations of 4.5, 5.5, and 1.5 μM, respectively. The degree of growth inhibition was dependent on the concentration of cells; higher drug concentrations were needed to produce inhibition of denser cell cultures. Binding studies with penfluridol showed that 50% growth inhibition resulted when approximately 50 μmoles of drug were bound per 106 cells. A 20‐min preincubation of cells with chlorpromazine (14.7 μM) inhibited DNA synthesis by 46%, and with penfluridol (4 μM) DNA synthesis was inhibited by 27%. The incorporation of labeled thymidine into the thymidine triphosphate pool was inhibited by chlorpromazine but not by penfluridol, indicating that the drugs produce their growth inhibitory effects by different mechanisms. TDP kinase activity was demonstrated in a particle‐free fraction of the cells. Its enzymatic activity was not affected by added chlorpromazine, penfluridol, or calmodulin, suggesting that inhibition of DNA synthesis by these drugs may be a consequence of growth inhibition.
Negative Phototaxis in Blepharisma japonicum
Authors: MATSUOKA TATSUOMI 
Published: May 2007

ABSTRACTThe protozoan Blepharisma japonicum showed negative phototaxis caused by transient reversal of the direction of ciliary beat and changes of swimming velocity induced with varying intensities of light. The ciliary reversal occurred at 1–2 sec after a sudden increase in light intensity. When light intensity was decreased, no response was observed. Moreover, the ciliates swam fast in light areas but slowly in dark areas; the mean velocity of swimming was 80 μ m/sec at 5 × 102 lux but reached about 400 μMm/sec at 5 × 103 lux. In addition, the cell body elongated in response to light application; the mean length of the body was 308 μm at 5 × 102 lux, which increased to 397 μ m at 104 lux. Such body elongation seems to contribute to rapid swimming. Negative phototaxis may be an important behavior in B. japonicum because the organisms are killed by exposure to strong light.
The Structure and Composition of the Stalk of the Ciliated Protozoan Sorogena stoianovitchae1
Authors: BLANTON RICHARD L. , WARNER STEVEN A. , OLIVE LINDSAY S. 
Published: May 2007

ABSTRACTSorogena stoianovitchae is an unusual ciliated protozoan with a life cycle characterized by the aggregation of individual trophic cells to form a multicellular sorogen that rises from the liquid culture medium surface by the secretion of a stalk. The noncellular stalk is a tapered, longitudinally furrowed structure composed of a fibrillar matrix that is initially hydrated, but with time dehydrates, the stalk becoming thin and brittle. This dehydration is of importance from the earliest stages of stalk formation since it results in the formation of the outer sheath‐like region of the stalk that appears to provide much of the support of the stalk. Cytochemical tests of the stalk for polysaccharides (including acidic mucopolysaccharides) and proteins are positive. Proteolytic enzymes degrade the stalk. Lectins specific for glucose and N‐acetyl‐D‐glucosamine bind to the stalk. Gas chromatography analysis detected the presence of fucose, glucose, glucosamine, and arabinose, as well as a variety of amino acids, predominantly glycine. The cytochemical and biochemical tests, the ultrastructural data, and the behavior of the stalk material suggest that the staik is composed of a matrix of complex protein‐polysaccharide molecules.
The Sterol Requirement of Tetrahymena setosa HZ‐11
Authors: GUYER WALTER , BLOCH KONRAD 
Published: May 2007

ABSTRACTThe growth rate of Tetrahymena setosa cells is stimulated significantly by as little as 0.1 μg and optimally by about 1 μg of ergosterol per ml of medium. Cell yields in the stationary phase are, however, not perceptibly affected by increasing sterol concentrations. Ergosterol, in concentrations that stimulate growth optimally, does not cause a reduction of tetrahymanol synthesis. The latter process is impaired only at much higher ergosterol concentrations. Epicholesterol and coprostanol inhibit ergosterol‐stimulated growth competitively. It is concluded that the trace amounts of sterol needed by T. setosa do not serve to replace tetrahymanol but function in some other manner, probably unrelated to the control of membrane fluidity. This conclusion supports the views advanced earlier by Holz, Erwin, Wagner & Rosenbaum.
Resting Cysts in the Ciliate Class Polyhymenophorea: Phylogenetic Implications1
Authors: REID P. C. , JOHN A. W. G. 
Published: May 2007

ABSTRACTDistinctive organic‐walled resting cysts of at least three different types with a highly conservative morphology appear to characterize specific orders or groups of genera within the Class Polyhymenophorea (Protozoa, Ciliophora), contrasting markedly with the great diversity of form seen in trophic stages. Polyhymenophorean ciliates have been considered in the past to form a cohesive class within the Phylum Ciliophora and, possibly, to represent the pinnacle of ciliate evolution. Evidence from cysts challenges the cohesive nature of the class, suggesting that the hypotrichs should be subdivided and that they have a different phylogenetic origin from the heterotrichs, tintinnids, and oligotrichs.
Microsporidian Spore Discharge and the Transfer of Polaroplast Organelle Membrane into Plasma Membrane
Authors: WEIDNER EARL , BYRD WILLIAM , SCARBOROUGH ANN , PLESHINGER JOHN , SIBLEY DAVID 
Published: May 2007

ABSTRACTElectron microscopic examinations of Glugea hertwigi and Spraguea lophii spores indicated the presence of a single plasma membrane; however, this membrane remained in the spore during the discharge of the sporoplasm from the spore. Although discharged spores retained the old plasma membrane, the extruded sporoplasms acquired a new plasma membrane. In order to determine where the new plasma membrane came from, we used two fluorescent probes with membrane affinities. The markers were tested on unfired and discharged spores. The probe, N‐phenyl‐1‐naphthylamine (NPN), labeled the polaroplast membrane in addition to the apolar groups in the posterior vacuoles of unfired spores. After spore discharge, NPN label disappeared from the spore ghosts except for a slight fluorescence on residual plasma membranes. Much of the NPN‐labeled membrane reappeared after spore discharge on the outer envelope of discharged sporoplasms. The probe chlorotetracycline (CTC) labeled calcium‐associated membranes of spore polaroplasts. During spore discharge, the CTC fluorescence shifted from the polaroplast organelle of unfired spores to the outer envelope of discharged sporoplasms. These results indicate that the polaroplast organelle may provide the new plasma membrane for discharged microsporidian sporoplasms.
Sporocarp Ulrastructure and Development in the Protostelid Cavostelium apophysatum1
Authors: WHITNEY KENNETH D. 
Published: May 2007

ABSTRACTUltrastructural observations on the sporocarp of the protostelid Cavostelium apophysatum are presented, including information about the mechanism of sporocarp development. The onset of sporogenesis is marked by cessation of trophic activity and the secretion of a protective sheath. The protoplast gradually molds itself into two distinct zones approximating the shape of the final sporocarp–a hyaloplasmic pre‐stalk zone and a globose incipient spore zone. The protoplast in the stalk zone deposits a fibrillar and amorphous stalk acropetally as the stalk protoplast moves into the incipient spore region. The last portion of the stalk to be deposited is the apophysis, a hollow cup‐like structure at the stalk apex. Spore wall deposition begins as the stalk nears completion. The wall consists of a single electron‐dense layer ornamented with hollow cones and solid projections. The mechanism of sporocarp development in C. apophysatum is compared to the developmental patterns of the protostelids Planoprotostelium aurantium and Schizoplasmodiopsis amoeboidea.
The Ejectisomes of the FlagellateChilomonas paramecium: Visualization by Freeze‐Fracture and Isolation Techniques1
Authors: GRIM J. NORMAN , STAEHELIN L. ANDREW 
Published: May 2007

ABSTRACTFreeze‐fracture procedures were used to visualize ejectisomes and adjacent plasma membrane specializations in the flagellate protozoanChilomonas paramecium. The ejectisomes are membrane‐bounded, cylindrically rolled, extrusive organelles. Small ones occur in large number beneath the plasma membrane of the body and considerably larger ones are located around the gullet membrane. The intra‐membrane particle distribution is different in each type. In small ejectisomes, the portion of the membrane in contact with the plasma membrane of the body has a P‐face rosette of five particles while the plasma membrane has not been observed with a rosette. Small ejectisomes and plasma membrane both contain aggregations of particles a short distance from the contact or docking site. Slightly beneath the plasma membrane is the periplastic sheet with which we speculate the small ejectisomes interact during the docking phenomenon. No obvious rosettes have been observed in large ejectisomes. Some other ejectisomal structures are presented and discussed.
Trypanosoma cruzi: Inoculation Schedules and Re‐isolation Methods Select Individual Strains from Doubly Infected Mice, as Demonstrated by Schizodeme and Zymodeme Analyses1
Authors: DEANE MARIA P. , SOUSA MARIA A. , PEREIRA NEIZE M. , GONÇALVES ANTONIO M. , MOMEN HOOMAN , MOREL CARLOS M. 
Published: May 2007

ABSTRACTGroups of mice received double infections with the Y and F strains of Trypanosoma cruzi, the first inoculum of either strain being followed by a second inoculum of the other strain on day 5, 15, 30–40, or 60–65. Parasites were re‐isolated from blood into culture, either directly or with an intermediate passage in gamma‐irradiated mice, at intervals between 7 and 35 days after the second inoculation. Strain identification in the re‐isolated material was by electrophoresis of kDNA fragments generated by the EcoRI restriction endonuclease and by electrophoresis for glucosephosphate isomerase isozymes. Both strains were identified in 22% of reislotes originating from the experimental mice and only one of them was present in the remaining re‐isolates, strain F being the most frequent. In some instances either Y or F was re‐isolated from the same blood source, depending on whether culturing had been preceded or not by passage through a mouse. These results are certainly related to strain differences in the various aspects of host‐parasite relationship and, possibly, growth rates in culture. The results demonstrate that: (1) more than one strain of T. cruzi can coexist in the same host; (2) the timing and method of parasite isolation from the vertebrate host act as selective factors, and further passages (inmice or cultures) may completely eliminate one (or more) strain from originally mixed trypanosome populations, and (3) kDNA restriction “fingerprints” and isozyme profiles are simple, sensitive, and reliable techniques for strain identification both in single and mixed preparations.
Trypanosoma cruzi: Quantification and Analysis of the Infectivity of Cloned Stocks1
Authors: DOYLE PATRICIA S. , DVORAK JAMES A. , ENGEL JUAN C. 
Published: May 2007

ABSTRACTThe infection of bovine embryo skin and muscle cells by trypomastigotes of four Trypanosoma cruzi clones (CA‐I/71, /72, Miranda/76, /80) was quantified. Stable and reproducible intra‐isolate differences were observed; an almost 70‐fold difference in infectivity occurred between clones. The CA‐I/71 clone was not susceptible to N‐acetyl‐D‐glucosamine at a concentration that inhibits the infection of vertebrate cells by Ernestina and Y‐strain parasites. Eight other monosaccharides that are common constitutents of vertebrate cell surface glycoproteins also failed to inhibit the infection of vertebrate cells by the CA‐I/71 clone.
Scanning Electron Microscopy of Toxoplasma gondii: Parasite Torsion and Host‐Cell Responses during Invasion1
Authors: CHIAPPINO MARY LOUISE , NICHOLS BARBARA A. , O'CONNOR G. RICHARD 
Published: May 2007

ABSTRACTScanning electron microscopy confirmed our previous finding that toxoplasmas actively invade mouse peritoneal cells that are inhibited from phagocytosis. The parasites entered cells with the conoid end first and sometimes showed a counter‐clockwise torsion of the body during invasion. Counter‐clockwise torsion was also noted in free toxoplasmas. Host‐cell responses to active invasion varied with experimental conditions and with the type of host cell. Under adverse culture conditions for phagocytosis, normal macrophages formed rudimentary filopodia or lamellipodia around the tips of in vading toxoplasmas; macrophages subjected to hyperthermia before similar incubation with toxoplasmas showed little or no response to invasion. Normal and heat‐treated lymphocytes showed little surface reaction to invasion, but occa ionally a flocculent collar was seen around the tip of an invading toxoplasma. Scanning electron microscopy provides clues to possil'e mechanisms of toxoplasma locomotion and host‐cell invasion.
New Aspects of the Morphology of Pleurotricha lanceolata (Ciliophora, Hypotrichida): Cirral and Membranellar Patterns and Fibrillar Systems
Authors: MARTÍN‐GONZÁLEZ ANA , SERRANO SUSANA , FERNÁNDEZ‐GALIANO DIMAS 
Published: May 2007

ABSTRACTIn Pleurotricha lanceolata, the ventral somatic infraciliature presents 13 frontoventral cirri, 5 transverse cirri, one row with 18–19 left marginal cirri and two rows of right marginal cirri of different length. On the dorsal side there are six longitudinal rows of dorsal bristles, four of them bipolar and the other two less than half body length. The oral infraciliature includes the adoral zone of membranelles, with 45–55 membranelles of three or four rows of kinetosomes each, and two undulating membranes (paroral and endoral membranes), each with two rows of kinetosomes. Some structures of the oral and somatic fibrillar systems have also been examined and are similar to those described in other species of hypotrichous ciliates.
Development of Caryospora simplex (Apicomplexa: Eimeriidae) from Sporozoites to Oocysts in Human Embryonic Lung Cell Culture1
Authors: UPTON STEVE J. , HAYNES T. BARRY , CURRENT WILLIAM L. , BARNARD SUSAN M. 
Published: May 2007

ABSTRACTLeighton tubes containing monolayers of human embryonic lung cells were inoculated with 70,000 or 30,000 sporozoites of the viperid coccidium Caryospora simplex and examined at 1, 2, 4, 6, 8, 10, 12, 14, 16, and 18 days post‐inoculation (PI). By day 1 PI, sporozoites had penetrated cells and were within parasitophorous vacuoles. Most sporozoites became spherical and then underwent karyokinesis several times between days 2 and 6 PI. Mature Type I meronts were found on days 6–16 PI and contained 8 to 22 short, stout merozoites. Mature Type II meronts were present on days 10–18 PI and contained 8 to 22 long, slender merozoites. Developing gamonts (undifferentiated sexual stages) were observed on days 14 and 16 PI. Mature micro‐ and macrogametes and thin‐walled unsporulated oocysts were present on days 16 and 18 PI. Attempts to sporulate oocysts in tissue culture medium or in a 2.5% (w/v) aqueous solution of K2Cr2O7 at 25/°C and 37°C were unsuccessful; only a few oocysts developed to the contracted sporont stage. Four Swiss‐Webster mice injected intraperitoneally with merozoites obtained from Leighton tubes on day 10 PI did not acquire infections. This is the second coccidium reported to complete its entire development, from sporozoite to oocyst, in cell culture.
Protozoan Colonization Rates and Trophic Status of Some Freshwater Wetland Lakes
Authors: HENEBRY MICHAEL S. , CAIRNS JOHN 
Published: May 2007

ABSTRACTPrimary productivity, chlorophyll a, phosphorus and nitrogen nutrients, and other chemical and physical parameters were measured in 13 wetland lakes in northern lower Michigan. These lakes included several examples located in each of the four major wetland types—bogs, fens, marshes, and swamps. Of the four types, the brown‐colored waters of the acid bog lakes generally had the highest levels of primary productivity, chlorophyll a, phosphorus, and nitrogen. Primary productivity correlated positively with water color, total‐N, and NH3‐N (α≤ 0.05). By these measures, waters of the bogs were the most eutrophic of the four types of wetland lakes. These findings would seem to contradict the generally‐held concept that “dystrophic” bog lakes are extremely oligotrophic.Protozoan colonization of artificial substrate islands was monitored at each wetland site. The correlation between protozoan colonization rates (G values in the MacArthur‐Wilson noninteractive model) and primary productivity, measured by 24‐h light and dark bottle incubations, was significant at the 95% confidence level (r= 0.850, P= 0.001) and with water color at the 90% confidence level (r= 0.599, P= 0.084). It was concluded that protozoan colonization rate was an excellent indicator of the trophic status of wetland lakes.
Purification and Properties of the Membrane Form of Variant Surface Glycoproteins (VSGs) from Trypanosoma brucei1,2,3
Authors: ALMEIDA M. LUCIA CARDOSO DE , ALLAN LINDA M. , TURNER MERVYN J. 
Published: May 2007

ABSTRACTVariant surface glycoproteins (VSG) of Trypanosoma brucei are released in a water soluble form on impairment of membrane integrity. We have previously shown that this release is the result of an enzyme‐mediated event which converts the hydrophobic membrane form VSG into the hydrophilic water‐soluble form. We now present further details of the methods by which membrane form VSG (mfVSG) may be isolated, uncontaminated by water‐soluble VSG (sVSG). The sensitivity to different metal ions of the enzyme that mediated the conversion event is discussed, and some biochemical characteristics of different mfVSG preparations are presented.
Localization of a Mg2+‐Activated ATPase in the Plasma Membrane of Trypanosoma cruzi1
Authors: MEIRELLES M. N. L. , SOUZA W. DE 
Published: May 2007

ABSTRACTThe Wachstein and Meisel incubation medium was used to detect ATPase activity in epimastigote, spheromastigote (amastigote), and bloodstream trypomastigote forms of Trypanosoma cruzi. Reaction product, indicative of enzyme activity, was associated with the plasma membrane covering the cell body and the flagellum of the parasite. No reaction product was found in the portion of the plasma membrane lining the flagellar pocket. The plasma membrane‐associated ATPase activity was not inhibited by ouabain or oligomycin, was detected in incubation medium without K+, was inhibited by prolonged glutaraldehyde fixation, and its activity was diminished when Mg2+ was omitted from the incubation medium. The Ernst medium was used to detect Na+‐K+‐ATPase activity in T. cruzi. No reaction product indicative of the presence of this enzyme was detected. Reaction product indicative of 5'‐nucleotidase was not detected in T. cruzi. Acid phosphatase activity was detected in lysosomes. These results indicate that a Mg2+‐activated ATPase is present in the plasma membrane of T. cruzi and that it can be used as an enzyme marker, provided that the mitochondrial and flagellar ATPases are inhibited, to assess the purity of plasma membrane fractions isolated from this parasite.
Effects of Cationized Ferritin and Neuraminidase on Invasion of Cultured Cells by Eimeria meleagrimitis Sporozoites
Authors: AUGUSTINE P. C. , DANFORTH H. D. 
Published: May 2007

ABSTRACTPrimary turkey kidney cells and Eimeria meleagrimitis sporozoites were treated with cationized ferritin (CF) or neuraminidase (NANase), and the effects on the invasion of the cells by the sporozoites were measured. Cultures of host cells pretreated with either compound contained significantly fewer intracellular sporozoites than did control cultures. There was little additive effect if cultures were first treated with NANase and then with CF. In contrast, pretreatment of sporozoites with CF or low concentrations of NANase had no effect on invasion. The inhibition of invasion was apparently due to an interaction between treatment substances and host cell surface rather than to direct effect on the sporozoites. The CF bound to the randomly distributed anionic sites on the surfaces of both host cells and sporozoites and then rapidly aggregated. Sporozoites, probably in the process of invading cells, were invariably found with the conoid in close association with aggregates of CF on the host cell membrane. The CF on the sporozoites was apparently shed before or during invasion because all intracellular sporozoites were completely devoid of the label.
Purification of Eimeria Sporozoites by DE‐52 Anion Exchange Chromatography
Authors: SCHMATZ DENNIS M. , CRANE MARK ST. J. , MURRAY P. KEITH 
Published: May 2007

ABSTRACTAn anion exchange column of DE‐52 has been used to purify Eimeria sporozoites from a post‐excystation mixture of oocysts, oocyst shells, sporocysts, sporocyst shells, and sporozoites. The mean recovery from several experiments was 94% and virtually all non‐sporozoite material was removed. Infectivity studies in vitro with sporozoites showed that they were viable after purification and were at least as infectious as the unpurified sporozoites; furthermore, oocysts in the crude preparation could be recovered from the DE‐52 cellulose by resuspending them in a 20% (w/v) sodium chloride solution.
Invasive Activity of Allogromia Pseudopodial Networks: Skyllocytosis of a Gelatin/Agar Gel1
Authors: BOWSER SAMUEL S. 
Published: May 2007

ABSTRACTTime‐lapse phase‐contrast videomicroscopy revealed that the psudopodial network of two allogromiid foraminiferense display an invasive behaviour, previously undescribed, which I term Skyllocytosis (Greek: skylo—to rend, tear, pluck). When these networks encounter an interface between a gelatin/agar overlay and a glass substratum, portions of the overlay are penetrated and partly surrounded by reticulopodia. By the coordinated activity and contraction of these reticulopodia, small segments of the overlay are ripped away. Manageable portions of the overlay are subsequently transported towords the cell body. In carnivorous foraminifera skyllocytosis may account for the removal of soft, autolysed tissues from dead invertebrate prey.