bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrastructural Study of Schizogony of Eimeria bovis in Cell Cultures*
Authors: DUBREMETZ JEAN F. , ELSNER YOKO Y.
Published: May 2007

SYNOPSIS. First‐generation schizogony of Eimeria bovis in bovine cell culture was studied by electron microscopy. The intracellular sporozoite retained its structure for at least 6 days at which time it rounded up and lost its apical complex. Although the refractile body underwent certain morphologic changes, it was retained throughout the parasite's growth. The beginning of mitosis was marked by the formation of a cytoplasmic funnel which traversed the nucleus opening on each side toward a pair of centrioles. Subsequently, there developed an intranuclear spindle. Separation of the daughter nuclei was preceded by the formation of typical centrocones. Differentiation of merozoites was accomplished by exogenesis during the last mitotic division. A dense fiber, interpreted as a link connecting the merozoite anlage with its nucleus, extended from the developing apical complex to the nearest division pole. In the anlage, the inner membrane complex was at first composed of patches associated with pairs of subpellicular microtubules. Rhoptries appeared early in merogenesis, whereas micronemes formed at the time the merozoites detached from the residuum. The level of amylopectin, low in schizonts, rose at the beginning of merozoite formation.
Microtubules Beneath the Pellicles of Two Ciliate Protozoa As Seen With the Sem
Authors: GRIM J. NORMAN , HALCROW KENNETH R. , HARSHBARGER ROBERT D.
Published: May 2007

SYNOPSIS. Chemical procedures remove some of the outer 3 limiting membranes of 2 ciliate protozoa, Euplotes eurystomus and Tetrahymena pyriformis, and reveal sheets of microtubules in their ectoplasm for SEM study. This greatly enhances the analysis of the 3‐dimensional geometry of these sheets, as is shown especially for E. eurystomus. In this organism, sheets of microtubules can readily be observed and described as they course through or around parts of the oral apparatus and other 3‐dimensionally complex regions.
Eimeria and Sarcocystis in Raccoons in Illinois1
Authors: ADAMS JOHN H. , LEVINE NORMAN D. , TODD KENNETH S.
Published: May 2007

Eimeria nuttalli oocysts were found in 58% (21/36) and E. procyonis oocysts in 25% (9/36) of raccoons Procyon lotor in Illinois, and sporocysts of Sarcocystis sp. in 17% (2/12) of other raccoons in Illinois. The oocysts of E. nuttalli were ellipsoidal to ovoid. 15–21 × 12–17 μm, with a one‐layered, smooth, colorless wall. The oocysts of E. procyonis were 22–28 × 18–22 μm, with a rough, striated, brownish, two‐layered wall. The sporulated sporocysts of Sarcocystis sp. were 11–13 × 8–10 μm. Attempts to infect baby pigs by feeding them sporocysts of Sarcocystis sp. from the raccoon failed.
In Vivo and In Vitro Localization of Leishmania within Macrophage Phagolysosomes: Use of Colloidal Gold as a Lysosomal Label1
Authors: BERMAN JONATHAN D. , FIORETTI THOMAS B. , DWYER DENNIS M.
Published: May 2007

The interaction of Leishmania with lysosomes within macrophages in vivo has been investigated. Lysosomes labeled with colloidal gold in vivo fused with phagocytic vacuoles containing Leishmania amastigotes within the macrophages of infected footpad tissue of BALB/c mice. This localization of Leishmania within macrophage phagolysosomes in vivo is the first confirmation for any obligate intracellulaire protozoon that parasite‐lysosome interactions in vitro occur in vivo.
Adaptive Use of N2‐Dimethyl‐Substituted Pterins by Cultures of Crithidia fasciculata1
Authors: ZIEGLER IRMGARD , BÖHME MANFRED , PFLEIDERER WOLFGANG , ELSTNER ERICH F.
Published: May 2007

The compound 6‐(L‐erythro‐1,2′,3′‐trihydroxypropyl)pterin, at a concentration of 50 pg/ml (“L‐erythro‐neopteria”), supports half‐maximal growth of Crithidia fasciculata; biopterin at a concentration of 30 pg/ml is shown to yield similar growth. N2‐dimethyl‐6‐(L‐erythro‐1′,2′,3′‐trihydroxypropyl)pterin (A) was inactive even at 100 ng/ml. Synergism was observed with the N2‐dimethylamino derivative (A) in the presence of suboptimal biopterin, its activity then being of the order of L‐erythro‐neopterin. In contrast, the stereoisomeric N2‐dimethyl‐6‐(D‐erythro‐1′,2′,3′‐trihydroxypropyl)pterin (“dimethyl‐D‐erythro‐neopterin”) and its 3′‐mono‐phosphate only slightly enhanced growth under similar conditions but both threo‐isomers had no supplementary activity. Biopterin‐induced growth was slowed by 6‐(D‐erythro1′,2′,3′‐trihydroxypropyl)pterin (D‐neopterin); the threo‐isomers had no such effect. An adaptive demethylation capacity by growing cultures and competition of biopterin uptake by D‐neopterin seems likely. The report of the occurrence in Euglena of N2‐dimethyl‐6‐(L‐threo‐1′,2′,3′‐trihydroxypropyl)pterin and its 3′‐mono‐phosphate adds further interest to our observations.
Generation Time and Growth Rate of the Human Intestinal Parasite Blastocystis hominis
Authors: ZIERDT CHARLES H. , SWAN JUDITH C.
Published: May 2007

ABSTRACT. Blastocystis hominis, an anaerobic intestinal protozoan parasite of man, has a generation time (GT) in axenic culture of 8.5–19.4 h, depending on the strain tested. Average GT of the eight strains was 11.7 h. Zero growth time cell counts of 5.0 × 105/ml to 2.0 × 106/ml rose in 3–5 days to 1 × 107 or 1 × 108 cells/ml. The GT was determined for the 24‐h period during which the most rapid growth occurred; about 2% of the B. hominis cells were in division during this time. Division under the culture conditions provided was by binary fission, the usual mode for B. hominis in vitro as well as in vivo. Division times were determined also by direct observation of individual dividing cells in slide cultures. These were usually ca. 40–60 min but sometimes as low as 20 min.
Biochemical Characterization of Secreted Proteases During Growth in Tetrahymena pyriformis WH‐14: Comparison of Extracellular with Intracellular Proteases
Authors: BANNO YOSHIKO , YANO KOH , NOZAWA YOSHINORI
Published: May 2007

Tetrahymena pyriformis strain WH‐14 secreted large quantities of intracellular proteases into its culture medium during growth. Extracellular enzymes were purified to homogeneity from cell‐free medium by ammonium sulfate precipitation, CM‐Sephadex column chromatography, gel filtration, and DEAE‐cellulose column chromatography. The DEAE‐cellulose eluates were separated into four peaks (P‐I, P‐II, P‐III, and P‐IV), each of which exhibited a different specific activity toward azocasein and α‐N‐benzoyl‐DL‐arginine‐ρ‐nitroanilide (Bz‐Arg‐Nan). These four forms of the protease showed similarity in amino acid composition, molecular weight (21,000–24,000), and antigenic reactivity. They had pH optima at neutral range. P‐I showed the highest specificity to azocasein whereas P‐IV was most effective toward the synthetic substrates. The Km values for hydrolysis of Bz‐Arg‐Nan were 2.4, 1.6, 1.3, and 1.4 mM for P‐I, P‐II. P‐III, and P‐IV, respectively, and the corresponding Kcat/Km values were 5.0, 9.4, 28.5, and 114.3 S‐1.M‐1. These properties of secreted proteases were compared with those of intracellular proteases purified by the same procedure except for the initial Triton X‐100 extraction. There were similarities in specific activity toward two substrates, molecular weight, Km, pH optima, and antigenic reactivity between the proteases from two sources, providing evidence that the intracellular proteases may be secreted into the extracellular medium without modification.
The Effect of Specific Sterols on Cell Size and Fatty Acid Composition of Tetrahymena pyriformis W
Authors: CONNER ROBERT L. , LANDREY JOSEPHINE R. , CZARKOWSKI NANCY
Published: May 2007

The size and fatty acid composition of Tetrahymena pyriformis W cells were influenced by the provision of a nutritional supplement of ergosterol, cholesterol, or tetrahymanol, but not of 20‐isocholesterol. Ergosterol and cholesterol addition led to a reduction in cellular volume, an increase in glycerophospholipid saturated fatty acid content, and an increase in palmitoleic acid and its metabolic products when compared to unsupplemented controls. Tetrahymanol supplementation resulted in an increase in cellular volume, a decrease in saturated fatty acid content, and a reduction in palmitoleic acid and derivatives. 20‐Isocholesterol was accumulated by the cells; however, this compound had no effect on any of the parameters followed in this investigation and had only a small depressant effect on tetrahymanol biosynthesis. Ergosterol and cholesterol had the same impact on the ciliates, even though the ergosterol‐supplemented cells contained approximately three times as much free sterol as did cholesterol‐grown cells. The amount of the free cholesterol and metabolic products in supplemented cultures was similar to the amount of tetrahymanol present in control cultures. This observation suggests that the cells recognize qualitative differences among the various polycyclic alcohols rather than responding to the amount of sterol present. Increased cellular levels of tetrahymanol led to a response unlike that of the true sterols, which again suggests that the high degree of specificity depends on the structure of the added polycyclic alcohol. The changes in fatty acid composition may be required to maintain proper interaction of the polar lipids and the polycyclic alcohols to give an appropriate degree of membrane fluidity.
Highly Purified Micro‐ and Macronuclei from Tetrahymena thermophila Isolated by Percoll Gradients1
Authors: ALLEN SALLY LYMAN , WHITE THEODORE C. , LANGMORE JOHN P. , SWANCUTT MARK A.
Published: May 2007

ABSTRACT. A new procedure is described that utilizes Percoll gradients for purifying micronuclei (MIC) and macronuclei (MAC) from Tetrahymena thermophila. Separation of MIC from MAC during certrifugation in Percoll gradients occurs as a result of their difference in size rather than density. Three kinds of tests were used to evaluate the purity of the nuclei: visualization of the nuclei by light microscopy; examination of the nuclei by electron microscopy; and Southern blots of MIC and MAC DNA probed with the 5s rRNA genes or a fragment from the MAC extrachromosomal rDNA molecule. When examined under the light microscope, the isolated MIC and MAC have much lower nuclear cross contamination levels than previous methods have reported. MIC's contaminated with less than 1 MAC in 1000 MIC and MAC's contaminated with less than 1 MIC in 500 MAC can be routinely prepared. Quantitative analyses of electron micrographs gave higher estimates of cross contamination in our purified nuclei, which may, in part, be explained by the difficulty in identifying small MIC or MAC fragments. Southern blots of MIC and MAC DNA probed with 5s rDNA confirmed the level of MAC contamination in the MIC estimated by light microscopy during purification of the nuclei. The level of nucleolar contamination in the MIC was estimated at 10% by Southern blots of MIC and MAC DNA, derived from a heterokaryon with distinctive MIC and MAC Bam HI sites, using an rDNA probe.
The Effects of Purine and Pyrimidines Upon Transformation in Tetrahymena vorax, Strain V2S1
Authors: BUTZEL HENRY M. , FISCHER JANICE
Published: May 2007

Column chromatography with Biogel P2 (molecular exclusion of 1800 daltons) indicates that the transforming principle causing microstomes to become macrostomes is a small molecule. Absorbance tests show that only those fractions with high absorbance at 260 nm have biological activity, indicating that the active principle is a component of nucleic acids. Tests of purines and pyrimidines show that purines are active, with hypoxanthine having the highest activity. The combination of hypoxanthine with uridine shows a synergistic reaction. As these two compounds are the natural catabolic excretory products from nucleic acids in Tetrahymena, the fact that they induce transformation in concentrated, starving cells may be a survival mechanism allowing cannibalism to be induced when nutrients are depleted, thereby allowing the survival of the transformed cells until such time as adequate nutritional conditions are restored.
Ultrastructure and Cortical Morphogenesis in the Euplotine Hypotrich Certesia quadrinucleata Fabre‐Domergue, 1885 (Ciliophora, Protozoa)1
Authors: WICKLOW BARRY J.
Published: May 2007

The cortical development during cell division and the interphase ultrastructure of the marine interstitial hypotrich Certesia quadrinucleata is described using light microscopy and both scanning and transmission electron microscopy. Membranelles are paramembranelles; postciliary microtubules from rightmost membranellar kinetosomes line the buccal cavity and separate parallel arrays of pharyngeal discs that border the cytopharynx. A large paroral membrane is present; an endoral membrane is absent. Alveolar plates lie within alveolar membranes except in regions where organelles and organellar complexes (cirri, the condylopallium, dorsal bristles, membranelles, and the paroral membrane) emerge from the cortex. Muciferous‐like bodies attach to the plasma membrane in these regions. Dorsal bristles possess transverse and postciliary microtubules as well as kinetodesmal fiber like those of other hypotrichs. Lasiosomes are present. A unique bulbous structure—the condylopallium—protrudes from the anterior right of the cell. The morphogenetic pattern is euplotine in that cortical development begins in one latitudinal zone, and the oral primordium of the opisthe develops within a subsurface pouch apart from the frontal primordia. Microtubular bundles appear beside (later attached to) developing frontal anlagen; they disappear after cirri are in final interphase locations. Although possessing unique characters, Certesia shares a close phylogenetic relationship with Euplotes.
Characterization of Two Sibling Species of the Genus Stylonychia (Ciliata, Hypotricha): S. mytilus Ehrenberg, 1838 and S. lemnae n. sp. II. Biochemical Characterization1
Authors: STEINBRÜCK GÜNTHER , SCHLEGEL MARTIN
Published: May 2007

The two closely related hypotrichous ciliate species, Stylonychia lemnae and S. mytilus, have been compared with respect to their isoenzyme patterns, their macronuclear DNA banding patterns, and micronuclear DNA banding patterns after restriction enzyme digestion. Since macronuclear DNA contains mainly protein‐coding sequences and since the micronuclear DNA patterns represent mainly the repetitive fraction of the genome, these results, together with the isoenzyme patterns, reflect differences on three different levels of molecular evolution between morphologically very similar species. Each of the three methods allows an unequivocal identification of each of the two species. Intraspecific variation seems to be greatest among the repetitive sequences of the micronuclear genomes. By using the isoenzyme data and the formula of Nei (19) the genetic distance between the two species is calculated and compared with the results from other protozoa and different Drosophila species. Despite their morphological similarity, the two species show a considerable amount of evolutionary divergence on the three molecular levels which have been investigated.
Leishmania mexicana mexicana: Attachment and Uptake of Promastigotes to and by Macrophages In Vitro1
Authors: BRAY R. S.
Published: May 2007

Promastigotes of Leishmania mexicana mexicana attach to mouse macrophages in vitro in the absence of serum by a wheat germ agglutinin‐like ligand on the surface of the promastigote that binds to the N‐acetyl glucosamine moiety of a receptor on the surface of the macrophage. The binding is temperature dependent, and the macrophage receptor is trypsin, cytochalasin B, and glutaraldehyde sensitive. The promastigote ligand is proteolytic enzyme and glutaraldehyde insensitive. Uptake follows attachment and is assisted or inhibited as for attachment. Treatment of promastigotes with proteolytic enzymes uncovers a receptor for a serum component that binds strongly to a mouse macrophage receptor in vitro. The strain of mice donating the macrophages had little effect upon attachment and uptake except that A strain mouse macrophages attached fewer promastigotes in 10 min than those of outbred mice, but took up as many promastigotes over 90 min as those of outbred mice. Low responder Biozzi mouse macrophages took up more promastigotes than high responder Biozzi mouse macrophages. Normal unheated human, rabbit, and guinea pig sera lysed promastigotes and so inhibited their attachment to macrophages in vitro. Unheated immune serum showed an enhanced inhibition of attachment. Heated normal serum allowed attachment and uptake, while promastigotes treated with heated immune serum showed enhanced attachment to and uptake by macrophages. Treatment of macrophages in vitro with immune serum enhanced their ability to attach promastigotes and to engulf them. Repeated 90‐min exposures of a population of promastigotes to uptake by mouse macrophages in vitro did not deplete the population of any sub‐population more likely to be taken by macrophages. The first sub‐population to be taken up survived better in macrophages over 24 h than subsequently engulfed sub‐populations.
Ultrastructural Localization of Enzymes Involved in the Feeding Process in Plasmodium chabaudi and Babesia hylomysci1
Authors: SLOMIANNY C. , CHARET P. , PRENSIER G.
Published: May 2007

In P. chabaudi, hemoglobin digestion occurs in two ways: micropinocytosis and cytostomal phagocytosis. Both mechanisms lead to the formation of digestive vesicles which evolve to pigment vesicles containing hemozoin crystals. We used ultrastructural enzyme cytochemistry to detect and localize endoarylamidase and aminopeptidase activity. In P. chabaudi, these two enzymes are at first detected at the level of cytoplasmic ribosomes. When pinocytic vesicles appear, enzyme activity is localized at the membrane of the newly formed vesicles. Then, the labelling extends to the vesicle contents where it becomes very prominent. In the late trophozoite, enzymatic activity decreases and is no longer detected. In B. hylomysci, no endoarylamidase activity can be detected. Aminopeptidase is noted in the cytoplasm, the labelling being heavier in the growing trophozoites than in the younger stages. No vesicles or pigment can be observed. We thus conclude that aminopeptidase or endoarylamidase are synthesized in the cytoplasm of P. chabaudi and migrate to the digestive vesicles where hemoglobin digestion occurs. We do not know whether Babesia degrades hemoglobin since it does not produce residual pigment. It could feed from small peptides or amino acids coming from or through the stroma of the red blood cell.
An Ultrastructural Study of the Myxosporeans, Sphaerospoa angulata and Sphaerospora carassii, in the Common Carp, Cyprinus carpio L.1
Authors: DESSER SHERWIN S. , MOLNAR KALMAN , HORVATH IREN
Published: May 2007

Sporogenesis of Sphaerospora angulata occurs in the lumen of renal tubules, and of Sphaerospora carassii sporogenesis occurs in the gill epithelium of carp (Cyprinus carpio) from Hungarian pond farms. In infected fish, the lumen of the renal tubules is filled with disporous pansporoblasts of S. angulata. Spores are formed through the participation of paired valvogenic and capsulogenic cells, and a dikaryotic sporoplasm, all of which lie in the cytoplasm of an envelope cell. The polar filament is formed through the apparent invagination of components of the elongate external tubule into the capsular primordium, coupled with the incorporation of dense material from the lumen of the primordium and external tubule. The cytological events leading to spore formation in monosporous pansporoblasts of S. carassii are similar to those of S. angulata and most other species of Myxosporea thus far. While neither parasite appears to induce severe pathogenesis, they may contribute to morbidity in concurrent infections with other microorganisms. Since spores of S. angulata and S. carassii are not formed in plasmodia and the earliest stage observed in this study was 2‐celled, earlier stages of these parasites must occur elsewhere in the carp host.
Ultrastructure of a Coccidium (Apicomplexa: Sporozoea: Coccidia) in Priapulus caudatus (Priapulida)1
Authors: McLEAN NORMAN
Published: May 2007

Stages in the life cycle of a coccidium are described from the intestine of Priapulus caudatus Lamarck, 1816. Meronts, merozoites, microgamonts, microgametes, and walled and unwalled macrogametes were seen in intestinal cells. Meronts were about 8 μm long and 3–7 μm wide and produced up to seven merozoites. Free merozoites were about 9 μm long and 4 μm wide and contained about 43 subpellicular microtubules that terminated in the outer polar ring. Microgamonts were up to 23 μm long and 7 μm wide and usually were delimited by a single membrane. Microgametes were about 5 μm long, exclusive of the two flagella, about 2 μm wide, and contained a nucleus that was not uniformly dense. Macrogametes, about 6 μm in diameter, had a nucleus largely without dense chromatin. The oocyst wall formed around intracellular macrogametes to a thickness of 0.2–0.5 μm as thin, osmiophilic elements that became arranged in reticular and tubular layers. Wall‐forming bodies were not seen, but fine filaments may participate in wall formation, as these were found between the outer membrane of the pellicle and the nearest wall elements. Microgametes and walled macrogametes were delivered to the lumen of the host intestine during apocrine secretion or excretion by the intestinal cells. Fertilization may occur in the intestinal lumen. Unsporulated ovoid oocysts, 18–27 μm long and 10–14 μm wide, with a 3 μm micropyle and a wall 0.6–0.7 μm thick, were passed from the host.
Ultrastructural Study of an Endosymbiotic Alga and Its Host Ciliate Stentor niger
Authors: KAWAKAMI HISAKO
Published: May 2007

Stentor niger collected in the suburbs of Hiroshima contained in its cytoplasm several hundreds of endosymbiotic algae and innumerable brownish pigment granules. The body of the ciliate was dark due to a mixture of the green endosymbiotic algae and brown pigment granules. The algae belonged to the genus Chlorella; each was enclosed in a perialgal vacuole and dispersed uniformly in the host cytoplasm from the myoneme layer inward to the center of the ciliate. The cell wall and plasma membrane of the alga enclosed a nucleus, chloroplast, mitochondrion, Golgi complex, accumulation bodies, myelinated vesicles, and many ribosomes. The chloroplast occupied more than half of the volume of the alga and contained a conspicuous pyrenoid. Algal multiplication occurred by two successive divisions of an alga, leading to four autospores within a perialgal vacuole; the walls of the vacuole invaginated to separate the autospores each into its own vacuole. Three types of pigment granules were scattered uniformly throughout the cytoplasm of the ciliate. The ultrastructure of the membranellar region, somatic cortex, and macro‐ and micronucleus of the ciliate are also described.
A Redescription of Hepatozoon mocassini (Laveran, 1902) n. comb. from Agkistrodon piscivorus leucostoma Troost, 1836
Authors: NADLER STEVEN A. , MILLER JOSEPH H.
Published: May 2007

Hepatozoon mocassini (Laveran, 1902) n. comb. from Agkistrodon piscivorus leucostoma (water moccasin) is redescribed by light microscopic study of all developmental stages and reclassified since mature oocysts contained sporocysts. Formerly this species was assigned to the genus Haemogregarina on the basis of a description of the gamonts. A neotype is designated because the original specimens cannot be located. Mature oocysts, containing sporocysts, developed in the hemocoel of the experimental host Aedes aegypti. These oocysts proved infective for A. piscivorus leucostoma when administered orally.
Effects of Chloroquine on the Feeding Mechanism of the Intraerythrocytic Human Malarial Parasite Plasmodium falciparum1
Authors: YAYON AVNER , TIMBERG RINA , FRIEDMAN SHOSHANA , GINSBURG HAGAI
Published: May 2007

Ultrastructural investigations of P. falciparum cultivated in vitro in human erythrocytes revealed new features of the feeding mechanism of the parasite. Mature trophozoites and schizonts take up a portion of the host cytosol by endocytosis which is restricted to cytostomes and which involves the invagination of both parasitophorous and parasite membranes. The resulting endocytic vesicles, surrounded by two concentric membranes, migrate towards the central food vacuole membrane. The external membrane of the endocytic vesicles apposes that of the food vacuole, leading to the internalization of vesicles bounded by a single membrane into the vacuolar space where they are rapidly degraded. We conclude from this sequence of events that endocytic vesicles fuse with the food vacuole. Treatment of infected cells with therapeutic concentrations of chloroquine inhibited the last step of the feeding process, i.e. vacuolar degradation. This was manifested by the accumulation within the vacuolar space of intact vesicles bounded by single membranes. The implications of these findings for the antimalarial activity of chloroquine are discussed.
Somatic and Oral Cortical Ultrastructure of the Plagiopylid Ciliates Lechriopyla mystax Lynch, 1930 and Plagiopyla minuta Powers, 19331
Authors: BERGER JACQUES , LYNN DENIS H.
Published: May 2007

The somatic and oral cortical ultrastructure of the plagiopylid ciliates Lechriopyla mystax Lynch, 1930 and Plagiopyla minuta Powers, 1933 are described. The somatic kinetids are monokinetids with an anteriorly directed kinetodesmal fibril originating near triplets 5, 6, 7, a divergent postciliary ribbon originating at triplet 9, and an unusual transverse ribbon originating in dense material adjacent to triplets 1, 2, 3. The transverse ribbon extends beneath the right surface of the cortical ridge adjacent to the kinety from which it originated. The oral kinetids are also monokinetids from whose base rootlet fibrils extend inwards beneath the oral kineties and converge on the furcula. The striated band on these ciliates is composed of a series of short ridges orthogonal to the longitudinal axis of the band. The sides of the striated band groove are apparently supported by macrotubules. The cortical ultrastructure of the plagiopylids is discussed with reference both to the optical microscopy of the organisms and to the ultrastructure of other ciliate taxa. The plagiopylids are not clearly related to any other higher taxon and are placed incertae sedis in the Subphylum Cyrtophora Small, 1976.
The Effect of Gamma Radiation on Nosema algerae (Microspora: Nosematidae) Spore Viability, Germination, and Carbohydrates1
Authors: UNDEEN ALBERT H. , MEER ROBERT K. VANDER , SMITTLE BURRELL J. , AVERY SUSAN W.
Published: May 2007

Spores of Nosema algerae Vávra & Undeen were exposed to 5 to 3000 KR of gamma radiation, then assayed for viability in Anopheles quadrimaculatus Say, and tested for germination in vitro. There was a dosage‐dependent loss of viability between 5 and 100 KR. Immediately after exposure to radiation at dosages between 1000 and 3000 KR, the spores progressively lost ability to germinate in 0.2 M KCl, pH 9.5. Between 250 and 1000 KR spores germinated well immediately after irradiation but, over a time span of days, fewer spores were able to germinate. Gamma radiation at 1000 and 2500 also caused a decrease in intrasporal trehalose concentration. The decline in percentage germination and trehalose concentration was more rapid at the higher dosages than the lower dosages.
Cytological Studies of Trichophrya rotunda (Hentschel)1
Authors: MOGENSEN METTE M. , BUTLER R. D.
Published: May 2007

Morphological, ultrastructural, and reproductive studies of a suctorian suggest its designation as Trichophrya rotunda (Hentschel) as distinct from Heliophrya collini, Heliophrya rotunda, and Craspedophrya rotunda of previous descriptions. Trichophrya rotunda has a round or slightly irregular, dorsoventrally flattened body (37–73 μm) with peripheral tentacles arranged randomly within 4–13 fascicles, a central polymorphic macronucleus, and 7–21 peripheral contractile vacuoles with ventrally terminating discharge pores. The tentacles are contractile and highly flexible. The axoneme consists of microtubules forming seven curved lamellae and 35 outer microtubules, which are separated into seven groups. Deviations from this prevailing pattern include helically arranged lamellae at the points of apical and basal termination, outer ring microtubules joined in an apical connective sheath, and the presence of a basal connective sheath near the point of axoneme termination. In common with other suctorians the cortex is multilayered and the cytoplasm contains characteristic organelles such as crescentic bodies and elongate dense bodies, but the haptocysts have unusual radial projections. Trichophrya rotunda feeds readily on motile vorticellids, attachment of the tentacular knobs occurring at their trochal band. Reproduction is endogenous, producing a single, slightly flattened, oval‐shaped swarmer with five equatorial kineties. The swarmer cytoplasm shows no evidence of primordia of tentacle axonemes nor any stages in development of the tentacle.
Inhibition of Growth of Giardia lamblia by Difluoromethylornithine, a Specific Inhibitor of Polyamine Biosynthesis1
Authors: GILLIN FRANCES D. , REINER DAVID S. , McCANN PETER P.
Published: May 2007

Difluoromethylornithine (DFMO) is a specific and irreversible inhibitor of ornithine decarboxylase, an enzyme which catalyzes the first step in the biosynthetic pathway of the polyamines. We tested the effect of DFMO on the growth of Giardia lamblia, Entamoeba histolytica, and Trichomonas vaginalis. Growth of G. lamblia was inhibited by DFMO at concentrations of ≥ 1.25 mM. Culture doubling time increased with increasing DFMO concentration. Growth inhibition was reversed if spermidine was added within 53 h of addition of DFMO; no growth was observed if spermidine was added later, indicating eventual parasite death. The growth of E. histolytica and T. vaginalis, two unrelated mucosal‐dwelling parasites of humans, was not inhibited by 20 mM DFMO. These studies indicate that polyamine biosynthesis from ornithine is required for growth of G. lamblia.
Infection with Eimeria tenella: Modulation of Lymphocyte Blastogenesis by Specific Antigen, and Evidence for Immunodepression1
Authors: ROSE M. ELAINE , HESKETH PATRICIA
Published: May 2007

ABSTRACT. The blastogenic effects of specific parasite antigen and of mitogens on the lymphocytes of chickens infected with Eimeria tenella were examined. Lymphocytes from infected chickens were stimulated to divide when cultured with parasite antigen, but their responses to the T‐cell mitogen, phytohemagglutinin (PHA), were depressed throughout the period of infection. Responses to the B‐cell mitogen, lipopolysaccharide (LPS), were depressed during the first week of infection but enhanced in the second week. The inclusion of plasma samples from infected chickens in the culture medium depressed the responses of normal spleen lymphocytes to PHA, suggesting that soluble suppressor factors are generated during infection.
Initial Extracellular Development in Vitro of Merozoites of Plasmodium falciparum1
Authors: TRACER WILLIAM , LANNERS H. NORBERT
Published: May 2007

ABSTRACT. Late schizonts from continuous cultures of P. falciparum were concentrated over Percoll, inoculated to various experimental media at the rate of about 20 × 106 per 0.5 ml of medium, and incubated in a candle jar at 37° for 1 day. Controls in standard culture medium showed a heavy invasion with young rings in the previously uninfected red cells introduced with the inoculum of schizonts. In a medium of high potassium content containing a 33% extract of human erythrocytes, this invasion was inhibited and many free merozoites were present. If, however, this same medium was supplemented with both ATP, as the dipotassium salt at 1.6 mM, and sodium pyruvate at 3.6 mM, there appeared large numbers of extracellular forms resembling young rings. Examination of these by electron microscopy shows that they are indeed merozoites that have begun to differentiate extracellularly. This suggests that the trigger for differentiation of merozoites may not depend on the process of entry into a red cell but rather on specific factors within the red cell.
The Role of Birds as Definitive Hosts and Intermediate Hosts of Heteroxenous Coccidians
Authors: ČERNÁ Ž.
Published: May 2007

ABSTRACT. Sarcocystis‐like oocysts‐sporocysts were found in four species of owls (Asio otus, Bubo bubo, Strix aluco, and Tyto alba) and in five species of predatory birds (Accipiter gentilis, Accipiter nisus, Buteo buteo. Circus aeruginosus, Falco tinnunculus). In addition, the muscles of 15 of 41 (36.5%) pheasants (Phasianus colchicus) and one of two jays (Garrulus glandarius) were found to harbor three types of Sarcocystis. Three of 15 (20%) infected pheasants had type I cystozoites (6‐8 × 2 fim) in muscle homogenates, but sarcocysts were not seen whereas the other 12 infected pheasants had type II cystozoites (16 × 2‐3 pm) and sarcocysts (90 × 600 μm) in their muscles. The one infected jay had type III cystozoites (8‐10.5 × 2.5‐3 μm) and sarcocysts (35‐40 × >770 μm) in its muscles.
Nutritional Requirements of Plasmodium falciparum in Culture. I. Exogenously Supplied Dialyzable Components Necessary for Continuous Growth
Authors: Divo Alan A. , Geary Timothy G. , Davis Nella L. , Jensen James B.
Published: May 2007

Continuous cultivation of Plasmodium falciparum presently requires the nutritionally complex medium, RPMI 1640. A basal medium of KCl, NaCl, Na2HPO4, Ca(NO3)2, MgSO4, glucose, reduced glutathione, HEPES buffer, hypoxanthine, phenol red (in RPMI 1640 concentrations), and 10% (v/v) exhaustively dialyzed pooled human serum was used to determine which vitamins and amino acids had to be exogenously supplied for continuous cultivation. Supplementation of basal medium with calcium pantothenate, cystine, glutamate, glutamine, isoleucine, methionine, proline, and tyrosine was necessary for continuous growth. This semi‐defined minimal medium supported continuous growth of four isolates of P. falciparum at rates slightly less than those obtained with RPMI 1640. Adding any other vitamin or amino acid did not improve growth. Incorporation of several non‐essential amino acids, particularly phenylalanine and leucine, into proteins was markedly enhanced in the minimal medium compared to RPMI 1640.
Effects of Long‐Term in Vitro Cultivation on Leishmania donovani Promastigotes
Authors: Nolan Thomas John , Herman Robert
Published: May 2007

Promastigotes of Leishmania donovani that had been subcultued in modified Tobie's medium for 2 to 3 years showed decreased infectivity and lack of virulence for hamsters and mice compared to newly transformed promastigotes. Amastigotes derived from these long‐term promastigote cultures decreased in number rapidly in hamsters, but only slightly in mice, over a 48‐day period. In cultured mouse and hamster macrophags infected in vitro, amastigotes derived from long‐term cultures rapidly decreased to low numbers, which persisted. The same pattern was seen in macriphages treated with catalase, an inhibitor of the oxygen‐dependent killing mechanism of the macrophage. Promastigotes from long‐term cultures also differed from virulent first‐passage promastigotes in size, growth patterns in Tabie's medium, and in the quantities of some of their antigens.
Goussia polylepidis n. sp. (Apicomplexa: Sporozoea: Coccidia) from Chondrostoma polylepis (Pisces: Cyprinidae) of the Duero Basin (NW Spain)1
Authors: ÁLVAREZ‐PELLITERO M. P. , GONZÁLEZ‐LANZA M. C.
Published: May 2007

In the examination of 90 Chondrostoma polylepis caught in the Esla River, a coccidium of the genus Goussia was found in the swimbladder, peritoneum, kidney, and ureter. It is described as Goussia polylepidis n. sp. and its taxonomic affinities are discussed. Data on its prevalence and seasonality are also given.
Enzyme Composition and the Taxonomy of Acanthamoeba
Authors: COSTAS MENELAOS , GRIFFITHS ALAN J.
Published: May 2007

The enzyme activities of 37 representative strains of Acanthamoeba against 19 substrates have been examined. A total of 13 enzyme complements were identified, which could be arranged in six larger groups. There was good agreement between these groupings and the arrangement of the strains that was suggested by the electrophoresis patterns of their esterases and acid phosphatases. A nomericlature is described which provides an unequivocal numerical label for each enzyme complement.
Experimental Transmission of Caryospora simplex (Apicomplexa: Eimeriidae) to Palestine Vipers, Vipera xanthina palestinae (Serpentes: Viperidae)
Authors: UPTON STEVE J. , BARNARD SUSAN M.
Published: May 2007

ABSTRACT. Four littermate, laboratory‐reared Palestine vipers, Vipera xanthina palestinae (#149, #150, #151, #152) (Serpentes: Viperidae) were used to determine modes by which Caryospora simplex (Apicomplexa: Eimeriidae) could be transmitted to snakes. Viper #149 was inoculated orally by stomach tube with 5.0 x 104 sporulated oocysts of C. simplex obtained from the feces of an Ottoman viper, V. x. xanthina and began passing unsporulated oocysts of C. simplex 121 days post‐inoculation (DPI). Viper #150 was fed five mice that had been inoculated orally £25 days previously with 5.0 x 104 sporulated oocysts of C. simplex and it began passing unsporulated oocysts of C. simplex 33 days after being fed the first two of five mice. Viper #151 was inoculated orally with sporulated oocysts of C. simplex obtained from viper #150 and began passing oocysts 52 DPI. Viper #152 served as an uninoculated control and did not pass oocysts of any species of coccidian. This study demonstrates that snake/snake and mouse/snake transmission of C. simplex readily occurs.
Food Vacuoles During Heat‐Shock‐Induced Transformation from the Microstomal to the Macrostomal Cell Type of Tetrahymena vorax1
Authors: SMITH‐SOMERVILLE HARRIETT E. , VERCHOT MARTHA E. , RYALS PHILLIP E.
Published: May 2007

ABSTRACT. The heat‐shock method for induction of the macrostomal form of Tetrahymena vorax involves the transfer of cells to reduced nutrient medium and the application of a series of elevated temperature shocks followed by washing the protozoa into inorganic medium. The component of the procedure that had the greatest effect on food vacuoles was the heat shocks. At the end of the heat shocks, cells formed vacuoles at a lower rate than non‐heat‐shocked cells, but the size of the vacuoles formed was larger and the protozoa contained an increased number of vacuoles and total vacuolar membrane. The rate was further reduced by washing cells into nonnutrient medium. In the absence of the heat shocks, the medium had little effect on the capacity of the cells to form vacuoles although after 7.5 h in inorganic medium, the vacuoles formed were smaller and the protozoa possessed fewer vacuoles and therefore less vacuolar membrane. The amount of membrane required to form the cytopharyngeal pouch of the macrostomal cell type was equivalent to the surface area of food vacuoles present in cells prior to the onset of the heat shocks, but the number and surface area of vacuoles decline between the time of oral resorption and pouch development.
Ultrastructural Studies of the Zygote and Oocyst Wall Formation of Eimeria truncata of the Lesser Snow Goose1
Authors: GAJADHAR ALVIN A. , STOCKDALE P. H. G. , CAWTHORN RICHARD J.
Published: May 2007

ABSTRACT. Zygote development and oocyst wall formation of Eimeria truncata occurred in epithelial cells in renal tubules and ducts of experimentally infected lesser snow geese (Anser c. caerulescens). Post‐fertilization stages were present throughout the kidneys beginning nine days post‐inoculation. Initially, a single plasmalemma enclosed the zygote, and type 1 wall‐forming bodies (WF1) became labyrinthine and moved toward the surface. There, WF1 degranulated and formed the outer layer of the oocyst wall between the plasmalemma and a newly formed second subpellicular membrane. Several WF2 fused and formed the inner layer, of the oocyst wall between the third and fourth subpellicular membranes. Six subpellicular membranes were observed during wall formation. Other features of oocyst development were similar to those of other eimerian species.
Light and Electron Microscopic Observations on the Intraerythrocytic Development of Babesiosoma stableri (Apicomplexa, Dactylosomatidae) in Frogs from Algonquin Park, Ontario1
Authors: BARTA JOHN R. , DESSER SHERWIN S.
Published: May 2007

ABSTRACT. The intraerythrocytic development and ultrastructure of Babesiosoma stableri Schmittner & McGhee, 1961 are described from Rana catesbeiana and Rana septentrionalis from Algonquin Park, Ontario. Morphometric and chronological observations on B. stableri in an experimentally infected Rana pipiens support the hypothesis that two successive types of merogonic cycles occur within the erythrocytes of infected frogs; the first cycle gives rise to the second and the second cycle produces merozoites destined to become gamonts. Merozoites, meronts, and gamonts are described by light and electron microscopy. Merozoites are typically coccidian and have a trilaminate pellicle with micropores, approximately 40 sub‐pellicular microtubules, an apical and posterior polar ring, a conoid with two accessory rings and a pair of intra‐conoidal microtubules, three rhoptries and numerous micronemes, and a nucleus with a nucleolus and a paranuclear Golgi body. The gamonts are larger than merogonic stages and are isogamous. They have approximately 55 sub‐pellicular microtubules and large stores of amylopectin. These observations indicate that the genus Babesiosoma should be transferred from the Family Haemohormidiidae (Piroplasmida, Piroplasmia) to the Family Dactylosomatidae (Eucoccidiida, Coccidia).
Acid Intracellular Vesicles and the Cytolysis of Mammalian Target Cells by Entamoeba histolytica Trophozoites1
Authors: RAVDIN JONATHAN I. , SCHLESINGER PAUL H. , MURPHY CHERYL F. , GLUZMAN ILYA Y. , KROGSTAD DONALD J.
Published: May 2007

ABSTRACT. Entamoeba histolytica kills mammalian target cells in a multi‐step sequential process with separate adherence, cytolytic, and phagocytic events. In the studies reported here, we used fluorescein isothiocyanate linked to dextran to label the endocytic vesicles of the HM1 strain of E. histolytica and measure vesicle pH (5.1 ± 0.2 by spectrofluorimetry). Concentrations of NH4Cl (1.0–10.0 mM) sufficient to increase vesicle pH to °5.7 inhibited amebic killing of target Chinese hamster ovary (CHO) cells as assayed by trypan blue staining, by the release of 3H‐thymidine previously incorporated into CHO cell monolayers, and by the release of 111indium oxine from radiolabeled CHO cells. Similar effects were also observed with two other weak bases, primaquine and chloroquine (both 50 μM). In contrast, NH4Cl (10 mM) did not affect either the adherence or phagocytic events, as measured by amebic adherence to CHO cells at 4°C and by the binding and ingestion of 3H‐leucine‐labeled bacteria. In the presence of NH4Cl and and the carbohydrate ligand asialofetuin, there was no evidence of intracellular trapping of the amebic galactose‐inhibitable lectin; inhibition of adherence by cycloheximide (10 μg/ml for 3 h) suggested rapid turnover of the surface lectin. Prolonged exposure to NH4Cl for 48 h (which had no effect on amebic protein synthesis) or shorter exposure to cycloheximide (10 μg for 3 h) produced persistent inhibition of cytolysis. These results indicate that an uninterrupted acid pH in intracellular endocytic vesicles is necessary for the cytolysis of target cells by E. histolytica trophozoites.
Effects of DL‐Alpha‐Difluoromethylornithine on Leishmania donovani Promastigotes1
Authors: KAUR KIRAN , EMMETT KIM , McCANN PETER P. , SJOERDSMA ALBERT , ULLMAN BUDDY
Published: May 2007

ABSTRACT. Alpha‐difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase, has been demonstrated to be an effective agent against a variety of parasitic protozoa but not against Leishmania spp. In this report, we show that Leishmania donovani promastigotes in continuous culture are sensitive to the growth inhibitory and cytotoxic effects of DFMO. Incubation of the promastigotes with DFMO obliterates intracellular putrescine pools and depletes spermidine concentrations, which correlates with the onset of growth inhibition. The effects of DFMO on the growth and the intracellular polyamine pools can be reversed completely by the addition of 10 μM putrescine to the culture medium. These results suggest that the treatment of leishmaniasis may be amenable to chemotherapeutic manipulation by DFMO.
Encystation of Entamoeba invadens IP‐1 Is Induced by Lowering the Osmotic Pressure and Depletion of Nutrients from the Medium1
Authors: AVRON BOAZ , STOLARSKY TAMARA , CHAYEN ANN , MIRELMAN DAVID
Published: May 2007

ABSTRACT. Trophozoites of Entamoeba invadens IP‐1 can be induced to encyst in simple solutions composed of semipermeable constituents (buffer, salts, or sugars) provided that their osmotic pressure is in the range of 60–160 mosmol/kg. Optimal yield of mature cysts was obtained when the osmotic pressure of the medium was 110 mosmol/kg. Encystation could be obtained in the absence of serum although higher yields were obtained in its presence. No difference in the yield of mature cysts was found when either dialyzed or full serum was used. High yields of encystation were obtained (>70%) in the presence of 5% serum in solutions of NaCl, KCl, or MgSO4, suggesting that the mechanism of encystation is not induced via sodium or potassium channels. Cysts were obtained in the presence of 72 mM glucose, indicating that depletion of a carbon source is not the only requirement for encystation. A rapid change in the density of the Entamoeba cells was observed upon transfer of trophozoites (density 1.061–1.073 g/ml) from growth medium to the low osmotic pressure encystation solutions. Within the first 2 min their density decreased (to 1.050 g/ml), but it soon increased, reaching within 30 min a density higher than 1.120 g/ml. As the encystation process continued to completion, the density of the cells gradually decreased, the mature cysts reaching a density of 1.049–1.061 g/ml.
Studies on the Coccidian Parasites (Apicomplexa: Eimeriidae and Pfeifferinellidae) of Pulmonate Gastropods1
Authors: FRITSCHE THOMAS R.
Published: May 2007

Pulmonate and prosobranch gastropods collected in Minnesota and Washington were examined for the presence of coccidian parasites. Typical coccidian oocysts were recovered from the feces of 89 of 543 (16%) pulmonate snails representing the families Lymnaeidae, Physidae, Planorbidae, and Succineidae. No coccidial infections were apparent in 104 specimens representing the prosobranch families Viviparidae and Pleuroceridae. Oocysts identified as Pfeifferinella ellipsoides were recovered from 21 of 101 (21%) Stagnicola elodes, 2 of 94 (2%) Physa gyrina, and 4 of 67 (6%) Aplexa hypnorum although incidence of infection differed greatly (2–40%) dependent upon the locality sample. This coccidian has not been described previously from North America and is reported here from members of the families Lymnaeidae and Physidae for the first time. Twenty percent of Oxyloma retusa from one habitat were shedding oocysts slightly smaller than, but otherwise identical with, those of Alveocystis gugleri. A third as yet unidentified oocyst was recovered from up to 54% of Helisoma trivolvis. As a group, the coccidia of pulmonate molluscs have been poorly studied. The findings of this survey, however, suggest that these parasites may be more common and widely distributed in both the Basommatophora and Stylommatophora than previously believed.
Recording of Pinocytosis in Amoeba proteus by Microcalorimetry1
Authors: NÄSSBERGER L. , MONTI M.
Published: May 2007

In the present work we have found that microcalorimetry might be a useful method to record pinocytosis in Amoeba proteus. Sodium‐induced (67 mM) and potassium‐induced (75 mM) pinocytosis caused an increase in heat output of 130 and 325%, respectively. Heat production during lysozyme‐induced (0.43 mg/ml) pinocytosis increased about 100%.