bluuebunny/crossref_metadata_2025 huggingface dataset:
Freshwater Euplotes Species with a 9 Type 1 Cirrus Pattern Depend upon Endosymbionts1,2
Authors: HECKMANN KLAUS , HAGEN RUDOLF TEN , GÖRTZ HANS‐DIETER
Published: May 2007

The hypothesis is advanced that all freshwater Euplotes species with a 9 type 1 fronto‐ventral cirrus pattern (E. patella type) depend upon bacteria‐like endosymbionts. Aposymbiotic cells of these species are unable to divide. The hypothesis is based on the investigation of 40 different freshwater Euplotes stocks collected in Germany, France, the USA, and Japan. No symbionts were found in E. crenosus and E. palustris, freshwater species with 10 fronto‐ventral cirri, nor in E. muscicola, a representative of the freshwater Euplotes group with a 9 type 2 fronto‐ventral cirrus pattern (E. affinis type). Characteristic for the essential endosymbionts are multiple nucleoids, a feature described earlier for omikron, an indispensable symbiont of E. aediculatus. Although the symbionts differ from omikron and among each other in size, shape, and their average number per host, they are believed to be related to omikron. In two stocks a different type of bacterium was found in which no defined nucleoids can be detected. Transfer of this symbiont into aposymbiotic cells, originally carrying omikron, revealed that it can restore the ability to multiply. Similarly, omikron was also able to restore the ability to divide in cells freed of this symbiont. It is assumed that this different type of symbiont is a secondary invader of Euplotes which displaced the original omikron‐like endosymbiont. Some of the stocks were found to carry, in addition to omikron‐like symbionts, other symbiotic bacteria; E. daidaleos carries in addition an alga. The findings suggest that the freshwater Euplotes species with a 9 type 1 cirrus pattern are closely related to each other and evolved from an ancestor (probably of cirrotype 10) which already was dependent upon endosymbionts of the omikron type. It supports the view that the two subgroups of freshwater Euplotes forms with a cirrotype of 9 have evolved independently from each other from species with 10 fronto‐ventral cirri by losing a cirrus at different positions.
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

Morphological, 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

Ten 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

The 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

The 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

Sorogena 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

The 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

Distinctive 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

Electron 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

Ultrastructural 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

Freeze‐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

Groups 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

The 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

Scanning 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

In 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

Leighton 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

Primary 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

Variant 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

The 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

Primary 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

An 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.
Nosema helminthorum Moniez, 1887 (Microspora, Nosematidae):A Taxonomic Enigma1
Authors: CANNING ELIZABETH U. , GUNN A.
Published: May 2007

ABSTRACT. The microsporidian parasite known as Nosema helminthorum Moniez, 1887, parasitic in the tapeworm Moniezia expansa (Rudolphi, 1810), has been shown by electron microscopy to have two cycles of development, one with isolated nuclei, the other with paired nuclei (diplokarya). Both merogony and sporogony of the two separate sequences take place in direct contact with the host cell cytoplasm and ultimately give rise to unikaryotic and diplokaryotic sporoblasts. Sporogony is disporoblastic. The nuclear condition of the spores was not seen. The sequences, corresponding to those of the genera Unikaryon and Nosema, may be part of a single dimorphic life cycle and, if so, the species will have to be transferred to a new genus.
Problems in the Identification of Species of Eimeria
Authors: LONG P. L. , JOYNER L. P.
Published: May 2007

ABSTRACT. The paper is concerned with the principles upon which coccidia of the genus Eimeria may be characterized. Reference strains for comparative purposes usually are not available and the limitations of morphological data for speciation are discussed. The value of other parameters are considered such as host and site specificity, pathogenicity, immunological specificity, pre‐patent period, sporulation time, enzyme variation, and DNA buoyant density. The weight afforded to each of these parameters for specific identification may vary according to the parasite and host studied. Determinations of physiological and behavioral characteristics that are now becoming available should be included in species definitions wherever possible.
Protective Immunity to Sarcocystis capracanis‐Induced Abortion in Dairy Goats1
Authors: DUBEY J. P.
Published: May 2007

ABSTRACT. Eleven female goats (Nos. 1 to 11) were each inoculated orally with 104 sporocysts of Sarcocystis capracanis, and four female goats (Nos. 12 to 15) were not inoculated. Between 31 and 69 days after inoculation (DAI) goats were mated with a single buck; one goat (No. 5) did not breed. Eight inoculated goats were challenged with 105or 106 sporocysts, 135 DAI. Two of four goats challenged with 106 sporocysts and one of three goats challenged with 105 sporocysts aborted one month before the expected time of parturition. The three inoculated goats that were not challenged delivered healthy kids. All inoculated goats including the nonpregnant one (No. 5) were only mildly ill from the primary or challenge inoculations. Two of the four control goats challenged with 5 × 104 or 105 sporocysts aborted 21 days later, and both died of sarcocystosis 25 and 88 DAI. The two remaining control goats delivered normal kids. The results indicate that immunization prior to pregnancy protects some but not all goats from .Sarc0c.es/is‐induced abortion.
Pathological Changes and Immunity Associated with Experimental Eimeria vermiformis Infections in Mus musculus1
Authors: BLAGBURN BYRON L. , TODD KENNETH S.
Published: May 2007

ABSTRACT. Pathological changes and immunity induced by Eimeria vermiformis (Ernst, Chobotar & Hammond, 1971) were studied in outbred Swiss mice inoculated with 5000, 10,000, 20,000, or 40,000 oocysts. Cross immunity to E. ferrisi was also studied. In the case of E. vermiformis, mortality was dose dependent; most deaths were observed in the intermediate‐dose groups. Most deaths also correlated with peak oocyst output. Histopathologic changes consisted of an early neutrophil and mononuclear cell infiltration in the small intestine. Later, villus atrophy and crypt hyperplasia caused a decrease in the villus‐crypt ratio. During the acute phase (8‐10 days after inoculation), villus tips were eroded and parasites with necrotic debris filled the cryptal and intestinal lumina. Vacuolar changes were observed in epithelial cells of the small intestine. Neither parasites nor significant pathological changes were observed in extra‐intestinal organs. Mice were totally immune to reinfection with E. vermiformis 30 and 105 days after inoculation. Cross immunity was not observed between E. vermiformis and E. ferrisi.
Nucleolar Hypertrophy as an Indicator of Transcription in Cells Infected with Second Generation Meronts of Eimeria tenella1
Authors: MARQUARDT WILLIAM C. , BRYAN J. H. D. , LONG PETER L.
Published: May 2007

ABSTRACT. Changes in nuclei and nucleoli of cells of chicken cecum infected with Eimeria tenella were studied in living cells by interference microscopy and in fixed and stained tissues using light level microscopy. As soon as merozoites began to transform into second generation meronts, there was an increase in the size of both the nucleus and the nucleolus of the host cell. The dry weight of the nucleus increased somewhat, but there was a greater increase and a correlation of the dry mass of the nucleolus with the size of the parasite as measured by interference microscopy. In fixed and stained tissues, there was a correlation between the area of the nucleolus and the area of the parasite. Removal of nucleic acids with DNase and/or RNase showed high concentrations of both in the nucleoli and a residue of protein. The increased nucleolar size indicates a high level of transcription in infected cells and allows the conclusion that the parasite somehow induces transcription to occur. Since transcription is a highly specific process, the high degree of host and site specificity shown by nearly all coccidia is consistent with a hypothesis that the coccidia share a portion of the host genome.
Besnoitia darlingi (Apicomplexa, Sarcocystidae, Toxoplasmatinae): Transmission between Opossums and Cats1
Authors: SMITH D. D. , FRENKEL J. K.
Published: May 2007

ABSTRACT. Opossums (Didelphis marsupialis), act as intermediate hosts for Besnoitia darlingi and could be infected orally with sporozoites (oocysts) and bradyzoites (tissue cysts), or intraperitoneally (i.p.) with tachyzoites. Infections could presumably be transmitted through cannibalism. Cats (Felis catus), the definitive host, could be infected only with bradyzoites but not sporozoites. Oocysts shed by cats measure about 12 × 12 μm, resemble similarly sized oocysts of Toxoplasma gondii and Hammondia hammondi, and must be differentiated by the appearance of tissue cysts after experimental infection of intermediate hosts. Cats did not form tissue cysts of B. darlingi. Tachyzoites from the related B. jellisoni could be used in the Sabin‐Feldman dye test to determine the development of antibody to B. darlingi in opossums after infection.
Invasive Activity of Allogromia Pseudopodial Networks: Skyllocytosis of a Gelatin/Agar Gel1
Authors: BOWSER SAMUEL S.
Published: May 2007

Time‐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.
Further Studies of Dopamine Metabolism and Function in Tetrahymena1
Authors: Gundersen Robert E. , Thompson Guy A.
Published: May 2007

The large amounts of dopamine accumulated by cells of Tetrahymena pyriformis strain NT‐1 and secreted into their growth medium were found to depend primarily upon an extracellular, non‐enzymatic conversion of tyrosine to L‐dihydroxyphenylalanine (L‐DOPA); L‐DOPA was then rapidly taken into the ceils and transformed into dopamine enzymatically. Efforts to find physiologically significant dopamine binding sites on the cell surface or dopamine‐sensitive adenylate cyclase activity were unsuccessful, suggesting that the catecholamine does not function in Tetrahymena as it does in higher animals.
Biochemical Study of Proteins of Cortical Cytoskeleton in the Ciliate Isotricha prostoma1
Authors: Vigues Bernard , Metenier G. , Grolière C. A. , Grain J. , Sénaud J.
Published: May 2007

In Isotricha prostoma, proteins of isolated cortices retaining the ecto‐endoplasmic fibrillar boundary (EEB) have been separated by one‐ and two‐dimensional gel electrophoresis. In addition to that of tubulin, four main bands corresponding to polypeptide molecular weights of 185, 35, 23, and 22 kd have been observed on 9% SDS‐polyacrylamide gels. Supernumerary major bands within a low molecular weight range (11‐19 kd) are evident after separation on 7.5‐15% polyacrylamide gradient gels. Two‐dimensional analysis discloses ‐ 150 polypeptide spots, most of them focusing within an acidic pl range 4.6‐5.3. The cortical fibrillar structures are still distinguishable after incubation in solutions containing 1.0 M K. Cl (12 h) or 0.6 M Kl (8 h). A prolonged KI treatment (52 h), however, results in the removal of EEB filaments (˜4 nm in diameter) and of a large part of the kinetid elements, so that the insoluble material is mainly represented by a reticulum of 6‐nm filaments interconnecting the proximal regions of kinetosomes. Two proteins with MW of 58 and 63 kd appear to be constituents of this kinetosome‐associated filamentous reticulum. Some of the cortical proteins with MW ≤23 kd are the most likely candidates for components of EEB filaments. The absence of decoration with heavy meromyosin confirms that actin is not a major component of Isotricha cortical cytoskeleton.
Nutritional Requirements of Plasmodium falciparum in Culture. II. Effects of Antimetabolites in a Semi Defined Medium1
Authors: Geary Timothy G. , Divo Alan A. , Jensen James B.
Published: May 2007

A semi‐defined minimal medium, in which pantothenic acid is the only vitamin, was used to culture Plasmodium falciparum for the analysis of antimetabolite drugs. Analogs of riboflavin, nicotinamide, pyridoxine, and thiamin inhibited the growth of this parasite; for each drug, effects were much more pronounced after 96 h of exposure compared to 48 h. The most potent drug examined was 8‐methylamino‐8‐desmethyl riboflavin (IC50 value approximately 1.0 times 10‐10 M at 96 h). Avidin, a protein which complexes and thus inactivates biotin, did not affect parasite viability. Other antimalarial drugs, including chloroquine and quinine derivatives and antibiotics, were equipotent in the minimal medium and in RPMI 1640. Four strains of P. falciparum showed only minor differences in sensitivity to these antimetabolites. The use of prolonged drug exposure times and a vitamin‐depleted medium allowed the preliminary characterization of antimalarial antimetabolites in vitro.
Effects of Intestinal Contents from Normal and Immunized Mice on Sporozoites of Eimeria falciformis1
Authors: Douglass Thomas G. , Speer Clarence A.
Published: May 2007

The interaction of Eimeria falciformis sporozoites with the intestinal epithelium and with the intestinal contents from the cecum and colon of normal and specifically immunized mice was studied by light (LM) and scanning electron (SEM) microscopy. Fecal (FM) and enterocyte‐associated (EAM) mucus were removed from the cecum and colon of normal mice and mice that had been immunized 1, 6, 12, or 20 days earlier with a series of oral inoculations of E. falciformis oocysts. Sporozoite‐specific IgA, but neither IgM nor IgG, was detected by the immunofluorescent antibody test in FM and EAM from immunized mice. No sporozoite‐specific immunoglobulin was detected in normal mice. When examined by LM, sporozoites exposed to all FM and EAM preparations exhibited greater motility and excystation from sporocysts. At 4 h after incubation in FM or EAM from normal or immune mice, about 10% of the sporozoites appeared damaged, being non‐motile and non‐refractile. Immune FM and EAM caused agglutination of sporozoites and sporocysts and oocyst walls of E. falciformis. but did not agglutinate those of E. ferrisi. Scanning electron microscopy of in vitro interactions between E. falciformis sporozoites and intestinal contents revealed that sporozoites exposed to immune EAM were coated with particulate material whereas those exposed to normal EAM were relatively clean. Sporozoites exposed to immune FM were usually embedded within the mucus whereas those exposed to normal FM were situated on top of the mucus. No significant differences occurred between the length/width (L/W) ratios of sporozoites incubated in normal FM and EAM or in PBS. Sporozoites exposed to immune FM had significantly greater L/W ratios than those exposed to normal FM whereas those exposed to immune EAM had significantly shorter L/W ratios than ones exposed to normal EAM. Few of the sporozoites observed on the luminal surface of the colon and cecum of normal mice were covered by mucus and none was altered in shape or showed pellicular damage. Only a few sporozoites were observed on the luminal surface of the colon and cecum of immunized mice. Most of these were covered by mucus and some exhibited pellicular alterations.
Myxosporean Infections in Cultured Tilapias in Israel1
Authors: Landsberg Jan H.
Published: May 2007

Five new species of myxosporean parasite are described from cultured tilapias in Israel. These are: Myxosoma sarigi. Myxosoma equatorialis, Myxobolus israelensis. Myxobolus agolus, and Myxobolus galilaeus. The first four were found in hybrids of Oreochromis aureus x Oreochromis niloticus while Myxobolus galilaeus was found in Sarolherodon galilaeus. In addition, M. sarigi. M. israelensis, and Myxobolus sp. were also found in S. galilaeus. In the light of the present study, the taxonomy of myxosporean infections in tilapias is modified. Mature spores may localize in the melano‐macrophage centers of the spleen and kidney where ihey may eventually be destroyed. Nc cases of mortality have so far been associated with these parasites.
Coccidian Parasites (Apicomplexa: Eimeriidae) from Insectivores: New Species from Shrew Moles (Talpidae) in the United States1
Authors: DUSZYNSKI DONALD W.
Published: May 2007

All of 18 shrew moles, Neurotrichus gibbsii, collected in Oregon and Washington were infected with one or more species of coccidia. Three eimerians and one isosporan were identified and described as new species. Sporulated oocysts of Eimeria heterocapita n. sp. were subspheroid to ellipsoid, 25.5 times 21.4 (23–27 times 18–23) μm. A membranous, cap‐like structure was present at one pole of the oocyst, but a micropyle, oocyst residuum, and polar body were absent. Ovoid sporocysts were 13.6 times 10.0 (12–15 times 9–11) μm; a compact sporocyst residuum was present, but Stieda, sub‐, and parastieda bodies were absent. This species was found in 2 of 18 (11%) hosts. Sporulated oocysts of Eimeria neurotrichi n. sp. were avoid, 17.6 times 13.6 (16–20 times 11–16) μm; micropyle and oocyst residuum were absent, but a polar body was present. Ovoid sporocysts were 10.7 times 5.5 (9–12 times 5–6) μm; Stieda body and sporocyst residuum were present, but sub‐ and parastieda bodies were absent. This species was found in 2 of 18 (11%) hosts. Sporulated oocysts of Eimeria parastiedica n. sp. were subspheroid, 27.4 times 25.5 (25–30 times 22–28) μm; micropyle, oocyst residuum, and polar body were absent. Ovoid sporocysts, pointed at both ends, were 18.3 times 10.4 (16–20 times 9–11) μm; Stieda, sub‐, and parastieda bodies were present as was a sporocyst residuum. This species was found in 2 of 18 (11%) hosts. Sporulated oocysts of Isospora neurotrichi n. sp. were subspheroid, 13.9 times 12.0 (11–16 times 10–15) μm; micropyle and oocyst residuum were absent, but 1–3 polar bodies were present. Ellipsoid sporocysts were 9.2 times 6.1 (8–11 times 5–8) μm; sub‐ and parastieda bodies were absent, but a Stieda body and sporocyst residuum were present. This species was found in 17 of 18 (94%) hosts. Ten of 18 (56%) hosts were seen to be naturally infected with only one coccidium.
Balantidium prionuriumn. sp., Symbiont in the Intestine of the Surgeonfish,Prionurus punctatus1
Authors: GRIM J. NORMAN
Published: May 2007

During the spring of 1984, the ciliateBalantidium prionuriumn. sp. was collected from the intestinal lumen of the herbivorous surgeonfish,Prionurus punctatus, from the Gulf of California. The symbionts were found in five fish from two well separated collection sites. Morphostatic specimens average 51 μm x 42 μm, and thus fall within the size range of several other fish balantidia. But the presence ofBalantidiumin a saltwater fish has not been reported, and such a host difference alone supports at least provisional recognition of this organism as a new species.
The 5S and 5.8S Ribosomal RNA Sequences of Tetrahymena thermophila and T. pyriformis1
Authors: VAN BELL CRAIG T.
Published: May 2007

The nucleotide sequences of the 5S rRNAs of Tetrahymena thermophila and two strains of T. pyriformis have been determined to be identical. The 5.8S rRNA sequences have also been determined; these sequences correct several errors in an earlier report. The 5.8S rRNAs of the two species differ at a single position. The sequencing results indicate that the species are of recent common ancestry. Molecular evidence that has been interpreted in the past as suggestive of an ancient divergence has been reviewed and found to be consistent with a T. pyriformis complex radiation beginning approximately 30–40 million years ago.
Trypanosoma brucei: Differentiation of in Vitro‐Grown Bloodstream Trypomastigotes into Procyclic Forms1
Authors: SIMPSON AGDA M. , HUGHES DALLAS , SIMPSON LARRY
Published: May 2007

Trypanosoma brucei strain 366D trypomastigotes grown at 37°C in the presence of a human fibroblast cell line formed foci underneath the feeder cells whereas trypanosomes grown in the presence of a human epithelial cell line grew only in the culture supernatant. A culture system was developed to study the differentiation of bloodstream trypomastigotes grown in the epithelial cell system into procyclic trypomastigotes at 27°C. The morphological differentiation into the procyclic form was complete by 48 h. Cell division did not occur until 30–40 h after transfer to 27°C. Various characteristics of this system were examined, including the effect of the feeder layer, the type of medium, the presence of the metabolites cis‐aconitate and citrate, the preadaptation period, and the trypanosome cell concentration. The respiration of the recently differentiated procyclic cells was less sensitive to inhibition by CN‐than that of established procyclic forms, implying a delayed appearance of complete mitochondrial oxidative pathways. This trypanosome differentiation system has the advantage that the animal host is not needed and the entire process is carried out in in vitro culture.
Ultrastructural Features of Mitosis in Anisonema sp. (Euglenida)1
Authors: TRIEMER RICHARD E.
Published: May 2007

The fine structure of stages in mitosis in a colorless euglenoid, Anisonema sp., reveals that chromosomes remain condensed throughout the life cycle and are attached to the nuclear envelope at interphase. The onset of mitosis is marked by the anterior migration of the nucleus towards the base of the reservoir and by elongation of the nucleolus. The nuclear envelope persists throughout mitosis. Microtubules are generated in the peripheral nucleoplasm adjacent to the envelope and attach to the chromosomes while they are still associated with the envelope. The region of microtubular contact develops into a distinct layered kinetochore as the developing spindle with attached chromosomes separates from the nuclear envelope and moves into the nucleoplasm. The mature spindle consists of a number of subspindles each containing about 8–10 microtubules and a few associated chromosomes. Both chromosomal and non‐chromosomal microtubules are present in each subspindle and extend towards the envelope terminating at or near the nuclear pores. Chromosomal segregation is concomitant with nuclear elongation. By late division, an interzonal spindle develops in the dumbbell‐shaped nucleus and nucleolar separation occurs. Continued invagination of the nuclear envelope in the region of the interzonal spindle eventually separates the daughter nuclei. A remnant of the interzonal spindle persists in the cytoplasm until cytokinesis.
The Cytology of Sheep Rumen Ciliates. III. Ultrastructure of the Genus Entodinium (Stein)1
Authors: FURNESS D. N. , BUTLER R. D.
Published: May 2007

This study examines previously undescribed general and cytopharyngeal features of the genus Entodinium. The cytopharynx contains three types of microtubular ribbons underlying the cytostomal membrane as well as a loose palisade of nematodesmata. A protoesophagus composed of microtubular bundles associated with a fibrous wall lies internally to one side of an extrusible peristome on which the adoral zone of syncilia (AZS) is mounted. Macronuclear structures are very similar to those of other ophryoscolecids. The micronucleus has chromatin bodies forming a compact mass but lacks the thick wall found in other species. A tubular spongiome surrounds the contractile vacuole and the cytoproct is relatively undifferentiated. Cortical structure follows the usual five‐layered ophryoscolecid pattern with subcortical barren kinetosomes arranged into indistinct kineties. The infraciliature of the AZS has kinetosomes set upon a subkinetal rod and with associated bifurcated kinetodesmata and transverse microtubules, some of which extend into the cytopharynx. Components newly described for Entodinium are the one to three postciliary microtubules and the interkinetosomal centro‐lateral strand, all of which are present in other species of ophryoscolecid ciliates. The infraciliature of the paralabial ciliary tuft shows similar components to that of the main AZS, but lacks the subkinetal rod. The microtubular components of the cytopharynx are discussed in relation to the “alimentary” structures in other ophryoscolecids, and a relationship of these structures to dietary differences is suggested.