bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in Orthophosphate, Pyrophosphate and Long‐Chain Polyphosphate Levels in Leishmania major Promastigotes Incubated With and Without Glucose
Authors: BLUM J. J.
Published: May 2007

The intracellular levels of orthophosphate (P1), pyrophosphate (PP1) and short‐ and long‐chain polyphosphate (Poly P) were measured in Leishmania major promastigotes incubated in a phosphate‐free medium. In the absence of exogenous substrate, the levels of both P1 and PP1 increased during a 1 h incubation. The increase in both P1 and PP1 was prevented when glucose was present, but glycerol prevented the rise in P1 only. A rise in P1 and PP1 was also seen in cells incubated in the absence of exogenous substrate under anaerobic conditions. This was reversed upon addition of glucose plus oxygen. Polyphosphate, here shown to be present in L. major, was measured by means of a polyphosphate glucokinase assay. Short‐chain Poly P content did not differ between cells incubated for 1 h in the absence of exogenous substrate or in the presence of glucose or glycerol. Long‐chain Poly P content, however, was lower in cells incubated without glucose than in cells incubated with glucose and was also lower in cells incubated for 1 h with glycerol as compared with freshly washed cells. Up to 61% of the increase in P1 and PP1 that occurred in promastigotes incubated in the absence of exogenous substrate could have arisen from the concomitant decrease in long‐chain Poly P.
Ultrastructural Observations on the Gametocytic Stages of the Coccidium Tyzzeria chalcides Probert, Roberts & Wilson, 1988 from the Ocellated Skink Chalcides ocellatus
Authors: DASZAK P. , PROBERT A. J. , RUNHAM N. W. , WILSON I. B.
Published: May 2007

Gametogenesis of Tyzzeria chalcides Probert, Roberts & Wilson, 1988, from the ocellated skink, Chalcides ocellatus, occurs within the epithelium of the gali bladder. Transmission electron microscopy reveals that macrogamonts contain 2 types of wall‐forming bodies. Type I bodies are large densely stained structures associated with rough endoplasmic reticulum and the Golgi apparatus. They appear to be formed within the Golgi itself. Type II bodies are less densely stained, smaller and appear to form directly from the rough endoplasmic reticulum. Canaliculi are associated with Type I wall‐forming bodies and probably function to transport the wall‐forming bodies to the pellicle. Micropores occur in the pellicie and large amylopectin granules, lipid globules and dense bodies are found within the cytoplasm of the macrogamont. Mature microgamonts contain in excess of 20 microgametes, each of which has 2 flagella and an associated mitochondrion. Both types of gamont are found within a parasitophorous vacuole, in the host cell, which is filled with vesicular material on which the gamonts probably feed.
Vairimorpha necatrix in Adipose Cells of Trichoplusia ni
Authors: DARWISH AZIZA , WEIDNER EARL , FUXA JAMES R.
Published: May 2007

Vairimorpha necatrix infected adipose ceiis of the fat body organ of Trichoplusia ni larvae 3–31/2 days after exposure of the larvae to infective spores. During the subsequent 4–6 days, the parasitized adipose cells were hypertrophied in part due to the rapid propagation of V. necatrix schizonts. A calcium‐sensitive tubule network developed at the interface of the schizonts and the adipose ceil cytoplasm. The paired nuclei of V. necatrix have pores at the nuclear interface. The pores for each nucleus at this interface are spatially positioned so that they are in conjunction; hence, there is the potential for a channel system between the 2 nuclei.
Coated Vesicles from the Protozoan Parasite Trypanosoma brucei: Purification and Characterization
Authors: SHAPIRO STUART Z. , WEBSTER PAUL
Published: May 2007

ABSTRACT. A procedure was developed to purify a coated vesicle fraction from the protozoan parasite Trypanosoma brucei. Electron microscopy revealed a difference between T. brucei coated vesicles and clathrin‐coated vesicles from other eukaryotes: trypanosome vesicles were larger (100 to ISO nm in diameter) and contained an inner coat of electron‐dense material in addition to the external coat. Evidence suggests that the internal coat is the parasite's variant surface glycoprotein (VSG) coat. The SDS‐PAGE analysis shows the major protein of T. brucei coated vesicles has a molecular mass of 61 kD, similar to VSG; this protein was recognized in an immunoblot by anti‐VSG serum. Trypanosome coated vesicles also contain a protein which comigrates with the major protein (clathrin) of coated vesicles purified from rat brains. However, this protein is a minor component and it is not serologically cross‐reactive with mammalian clathrin. Immunoblot analysis demonstrated that the parasite vesicles contained host IgG, IgM, and serum albumin.
Characteristics of Basal Body Cartwheel Reassembly
Authors: GAVIN R. H. , DUFFUS W. A. , CONTARD P. C.
Published: May 2007

ABSTRACT. Cartwheel complexes reassembled in a fraction derived by treating isolated oral apparatuses from Tetrahymena with 1.0 M KC1 for 12 h. Approximately 40% of the KCl‐soluble protein reassembled into cartwheel complexes. The reassembly reaction was protein‐concentration dependent, and reassembled cartwheels were stable at 3° C. Sucrose gradient centrifugation resolved 3 high molecular mass protein complexes from the KCl‐soluble fraction. Each of the 3 complexes has a different mass, but each contains the same 5 polypeptides, 2 of which arc probably tubulins. When these complexes were removed from the KCl‐soluble fraction by high speed centrifugation, cartwheel reassembly did not occur. The 5 polypeptides in the high molecular mass complexes were among several other polypeptides resolved from reassembled cartwheels by 2‐dimensional gel electrophoresis. The high molecular mass complexes are probably essential for cartwheel formation. The electrophorctic data also show that several polypeptides in the KCL‐soluble fraction do not appear to be incorporated into cartwheels. These polypeptides are probably non‐essential for cartwheel formation.
Ultrastructural Observations on Life Cycle Stages of Pneumocystis carinii
Authors: RUFFOLO JOHN J. , CUSHION MELANIE T. , WALZER PETER D.
Published: May 2007

An ultrastructural study of life cycle stages of Pneumocystis carinii in infected rat lungs in situ was undertaken utilizing 8 different modes of fixation. Three of the fixatives employed gave good fixation of cysts and intracystic bodies, but for the trophic forms fixation was only fair. Both the trophic forms and intracystic bodies have nuclear pores. The mitochondria of the organism have cristac that appear lamellar. One of the fixation modes revealed a thin, electron‐dense layer on the outer surface of the cell wall, a “fuzzy coat” that had not been described previously. This material appears to mediate tight adhesion of trophic forms with other trophic forms, cysts, and with pneumocytes of the lung alveolus.
Surface Labeling of Pneumocystis carinii from in Vitro Culture
Authors: RADDING JEFFREY A. , ARMSTRONG MARTINE Y. K. , BOGUCKI M. SANDRA , RICHARDS FRANK F.
Published: May 2007

.Pneumocystis carinii is an opportunistic pathogen of man, carried as a commensal in healthy subjects. It frequently causes a fatal pneumonia in the immunosuppressed host. It is a major complication of HIV‐1 infection in man (AIDS). Using surface radioiodination of rat‐derived P. carinii trophozoites obtained from in vitro culture, a major surface glycoprotein (gpl20) has been identified. The glycoprotein exhibits adherent behavior similar to that of the intact organism. Purification of gpl20 by conventional methods was unsuccessful as the glycoprotein irreversibly bound to numerous column matrices. A combination of gel chromatography and hydroxyapatile chromatography in sodium dodecylsulfate was utilized to purify the glycoprotein. Some preliminary characterization of the glycoprotein is presented.
The Interaction of Naegleria fowleri Amoebae with Murine Macrophage Cell Lines
Authors: FISCHER‐STENGER KRISTA , CABRAL GUY A. , MARCIANO‐CABRAL FRANCINE
Published: May 2007

The present study was undertaken to determine whether murine macrophage cell lines exhibited in vitro amoebicidal activity comparable to that elicited by activated murine peritoneal macrophages. Peritoneal macrophages activated in vivo by bacillus Calmette‐Guérin or Propionibacterium acnes demonstrated significant cytolysis of Naegleria fowleri amoebae. The macrophage cell line RAW264.7 also effected cytolysis of amoebae, but to a lesser extent than that elicited by activated peritoneal macrophages. However, the macrophage cell lines, J774A.1 and P388D1, did not exhibit amoebicidal activity. Macrophage conditioned medium prepared from RAW264.7 macrophages mediated cytolysis of L929 tumor cells but had no effect on N. fowleri amoebae. In addition, neither recombinant tumor necrosis factor nor recombinant interleukin‐1 exhibited amoebicidal activity. Scanning electron microscopy of co‐cultures revealed that N. fowler bound to activated peritoneal macrophages and RAW264.7 macrophages. These results suggest that RAW264.7 macrophages treated in vitro with lipopolysaccharide are similar to macrophages activated in vivo in that they effect contact‐dependent cytolysis of Naegleria fowleri amoebae. The RAW264.7 macrophages are unlike primary macrophage cultures in that they either do not release soluble amoebicidal factors into the conditioned medium or they release insufficient quantities.
Naegleria lovaniensis tarasca New Subspecies, and the Purepecha Strain, a Morphological Variant of N. I. lovaniensis, Isolated from Natural Thermal Waters in Mexico
Authors: RIVERA FERMIN , CERVA LUBOR , MARTINEZ JULIO , KELETI GEORG , LARES FERNANDO , RAMIREZ ELIZABETH , BONILLA PATRICIA , GRANER SCOTT R. , SAHA ASISH K. , GLEW ROBERT H.
Published: May 2007

Amoebae were isolated from a natural thermal water source in Michoacaan, Mexico, in September 1986. Two 500‐ml samples were taken from pools with water at 45°C and 46°C and concentrated at 2,000 g for 15 min. The sediment was seeded on nonnutritive agar plates and incubated at 42°C. The isolates were axenized in bactocasitone‐serum medium. The identification of the isolates was based on their morphology, total protein and isoenzyme patterns by agarose isoelectric focusing, serology, fine structure, agglutination with Concanavalin A, sensitivity to trimethoprim, capacity to kill mice, and their cytopathic effect in Vero cells. The results showed several morphophysiological, biochemical and serological differences between the isolates and the type strain Aq/9/1/ 45D of Naegleria lovaniensis. These remarkable differences provide sufficient evidence to consider one of the isolates a new subspecies, and the other one a morphological variant of N. l. lovaniensis, which can be differentiated from other Naegleriae by their morphology, biochemistry, serology and physiology. The authors propose the name tarasca for the subspecies and purepecha for the morphological variant.
Peculiar Epibionts in Euplotidium itoi (Ciliata, Hypotrichida)
Authors: VERNI FRANCO , ROSATI GIOVANNA
Published: May 2007

ABSTRACT. Euplotidium itoi share with some other species of the same genus a peculiar feature: the presence of a band of particles running along the right and left borders of the cell body and forming a sort of “scarf” at the dorsal anterior end. The ultrastructural analysis, here performed, revealed that these particles (reported in the literature as extrusomes) are always external to the cell and are inserted in matching depressions on the euplotidium cortex. They are present in two different forms: type I, whose ultrastructure recalls that of bacteria, are able to reproduce by binary fission; type II are not able to divide and contain peculiar structures (a granular dome‐shaped zone, a complex extrusive apparatus and a network of regularly arranged fibrils) which render them more complicated with respect to the majority of prokaryotic organisms. These observations, together with the finding that these particles contain DNA, indicate that we are dealing with epibionts, that will be referred to as “epixenosomes” (ecto‐organisms), rather than extrusomes. Some ideas about the nature of “epixenosomes” and their relationship with the host cell are proposed and discussed.
A Survey for a Trypanocidal Factor in Primate Sera
Authors: SEED JOHN R. , SECHELSKI OHN B. , LOOMIS M. R.
Published: May 2007

ABSTRACT. The sera of 21 different species of primates were surveyed for the presence of a trypanocidal factor to a monomorphic human serum‐sensitive clone of Trypanosoma brucei gambiense (T.b.g.); human, gorilla, baboon (2 species), and the mandrill were found to contain this factor. The factor in all the sera is in the high density lipoprotein (HDL) fraction, and has similar modes of biological action. It has been shown that the human and gorilla trypanocidal factor share cross‐reactive antigenic epitopes, but do not share similar cross‐reactive epitopes with the baboon and mandrill factor. There was no relationship between the presence or absence of this factor and the primate's position on the phylogenetic tree. In addition, there was also no obvious correlation between the animals’preferred diet, and the presence or absence of trypanocidal activity. The evidence to date suggests that only African ground‐dwelling primates that live in tsetse endemic areas contain the trypanocidal factor. It is assumed that this factor is involved in resistance of these primates to T.b.b. We believe that the host has developed trypanocidal substances as a result of selective evolutionary pressure by the African trypanosomes.
Chromosomal Localization of an Exocytosis Mutant in Tetrahymena thermophila
Authors: BLEYMAN LEA K. , SATIR BIRGIT H.
Published: May 2007

ABSTRACT. Exocytosis mutants of Tetrahymena thermophila are deficient in mucus release. Experiments to chromosomally locate two of these mutants are described, using the technique of deletion mapping with nullisomic strains. One exo locus has been assigned to chromosome 5.
Populational Changes of the Enteric Protozoans Opalina spp. and Nyctotherus cordiformis During the Ontogeny of Anuran Tadpoles
Authors: SCHORR MARK S. , ALTIG RONALD , DIEHL WALTER J.
Published: May 2007

ABSTRACT. We studied ontogenetic population changes of Opalina and Nyctotherus cordiformis in eight species of tadpoles from 10 sites in east‐central Mississippi. Most tadpoles acquired Opalina early in development, while the acquisition of N. cordiformis was variable. Developmental stage, species and collection site explained significant amounts of the variation in Opalina density of tadpoles (F= 11.6; df = 27, 235; P < 0.0001) and metamorphs (F= 7.31; df = 24, 84; P < 0.0001). Relationships between Opalina density and host stage showed either (1) a gradual decrease or (2) a gradual increase throughout host ontogeny. Opalina densities declined during metamorphosis. Density variations of N. cordiformis were explained by host species of tadpoles (F= 9.30; df = 7, 142; P < 0.0001) and by host species and stage of metamorphs (F= 5.85; df = 8, 62; P < 0.0001).

The length of larval period, habitat duration and generation time of the protozoans are suggested as major modifiers of the protozoan densities. Hosts with long larval periods show a decreasing population density and hosts with short developmental periods show a pattern of increasing density. Neither pattern was detected in tadpoles from temporary sites. Metamorphic declines in protozoan density, but not necessarily the loss of protozoans, reflect metamorphic alterations of the gut common to all hosts.
Effects of Culture Age and Hexoses on Fatty Acid Oxidation by Leishmania major
Authors: BLUM J. J.
Published: May 2007

ABSTRACT. The effect of culture age on the rate of oxidation of short‐, medium‐, and long‐chain fatty acids by Leishmania major promastigotes was investigated. Promastigotes from 5‐day stationary phase cultures oxidized several saturated fatty acids about 3‐to‐4‐fold faster than cells from late log phase cultures, but [10−14C]oleate was oxidized 9‐fold faster. The increase in rate of oxidation was partially reversed within 5 h and almost completely reversed within 30 h after resuspending cells from a 5‐day stationary culture in fresh medium. Addition of acetate, leucine, or alanine caused moderate inhibitions of [1‐14C]palmitate oxidation, while glycerol had little effect. Glucose, however, was a powerful inhibitor of the oxidation of [1‐14C]palmitate and of [1‐14C]octanoate. Mannose and fructose were also strong inhibitors of palmitate oxidation, but neither galactose, 2‐deoxyglucose or 6‐deoxyglucose caused appreciable inhibition. The extent of inhibition by acetate increased with increasing culture age, whereas inhibition by glucose decreased. In addition to demonstrating a reversible rise in β‐oxidation capacity with culture age, these data also demonstrate a hitherto unrecognized strong and culture age‐dependent inhibition of fatty acid oxidation by glucose.
Characterization of an Axenic Strain of Hartmannella vermiformis Obtained from an Investigation of Nosocomial Legionellosis
Authors: FIELDS BARRY S. , NERAD THOMAS A. , SAWYER THOMAS K. , KING C. HAROLD , BARBAREE JAMES M. , MARTIN WILLIAM T. , MORRILL WILLIAM E. , SANDEN GARY N.
Published: May 2007

ABSTRACT. A free‐living amoeba identified as Hartmannella vermiformis was isolated from a water sample obtained during an investigation of nosocomial legionellosis. Hartmannella vermiformis is known to support the intracellular multiplication of Legionella pneumophila. This strain of H. vermiformis, designated CDC‐19, was cloned and established in axenic culture to develop a model for the study of the pathogenicity of legionellae. Isoenzyme patterns of axenically‐cultivated strain CDC‐19 were compared with two strains of H. vermiformis derived from the type strain, one axenic (ATCC 50236) and the other grown in the presence of bacteria (ATCC 30966). Enzyme patterns suggested that all three strains are assignable to the species H. vermiformis. Axenic H. vermiformis strain CDC‐19 has been deposited with the American Type Culture Collection (ATCC 50237) and should prove useful in the study of protozoan‐bacterial interaction.
Ascogregarina saraviae N. Sp. (Apicomplexa: Lecudinidae) in Lutzomyia lichyi (Diptera: Psychodidae)
Authors: OSTROVSKA KATHERINE , WARBURG ALON , MONTOYA‐LERMA JAMES
Published: May 2007

Ascogregarina saraviae n. sp. (Apicomplexa: Lecudinidae) is described from wild‐caught Lutzomyia lichyi (Diptera: Psychodidae) females. Gametocysts adhered to the hemocoel side of the genital accessory gland walls and oocysts were injected into their lumina. Sporulated oocysts were ellipsoidal, 12.4 × 5.8 (11.6–13.1 × 5.6–5.9) micrometers, contained eight sporozoites and a refractile residuum. The elongate form of A. saraviae n. sp. oocysts, and their more delicate walls, clearly distinguish them from oocysts of A. chagasi (Adler & Mayrink, 1961).
Identification of Sporozoite Surface Proteins and Antigens of Eimeria nieschulzi (Apicomplexa)
Authors: TILLEY MICHAEL , UPTON STEVE J.
Published: May 2007

Sodium dodecyl sulfate polyacrylamide gel electrophoresis, immunoblotting, lectin binding, and 125I surface labeling of sporozoites were used to probe sporozoites of the rat coccidian, Eimeria nieschulzi. Analysis of silver stained gels revealed >50 bands. Surface iodination revealed about 14 well labeled, and about 10 weakly labeled but potential, surface proteins. The most heavily labeled surface proteins had molecular masses of 60, 53–54, 45, 28, 23–24, 17, 15, 14, 13, and 12 kD. Following electrophoresis and Western blotting, 2 of the 12 125I labeled lectin probes bound to two bands on the blots, which collectively indicated that two bands were glycosylated. Concanavalin A (ConA) specifically recognized a band at 53 kD, which may represent a surface glycoprotein, and a lectin derived from Osage orange (MPA) bound to a single band at 82–88 kD, that may also be a surface molecule. Immunoblotting using sera collected from rats inoculated orally with oocysts, as well as sera from mice hyperimmunized with sporozoites, revealed that many surface molecules appear to be immunogenic.
Nolleria pulicis N. Gen., N. Sp. (Microsporida: Chytridiopsidae), a Microsporidian Parasite of the Cat Flea, Ctenocephalides felis (Siphonaptera: Pulicidae)
Authors: BEARD CHARLES B. , BUTLER JERRY F. , BECNEL JAMES J.
Published: May 2007

A new species of microsporidium, Nolleria pulicis, is described and named here from the cat flea, Ctenocephalides felis. The genus Nolleria is created and placed within the family Chytridiopsidae. The family is slightly modified to accommodate certain features of intracellular development seen in N. pulicis, which is otherwise very similar to other species in the family Chytridiopsidae. Sporulation is described from ultrastructural analysis of infected midgut epithelial cells of adult C. felis. The term “multiple division by vacuolation” is proposed for describing sporogony as it occurs in this species and certain related species of microsporidia. The probable mode of transmission and apparent absence of merogony are discussed.
Trypanosoma acomys (Wenyon, 1909): Continuous Culturing with a Mouse Fibroblast Cell‐Line (A9)
Authors: ABDALLAH MONA A. , ABDEL‐HAFEZ SAMI K. , AL‐YAMAN FADWA M.
Published: May 2007

The continuous culturing of Trypanosoma acomys in the presence of a murine areolar‐adipose cell line (A9) was possible for the 1st time. The trypanosomes were cultured at 37° C with A9 in DMEM supplemented with 20% heat inactivated fetal bovine serum, using an initial inoculum from primary cultures of lung or blood clots from infected spiny mice. The cultures were maintained for 115 days and underwent 15 passages before termination and cryopreservation. Using this culture system T. acomys subcultures were initiated from 3 different initial inocula (3 × 104, 1.5 × 105 and 7.4 × 105 parasites/ml) and growth curves revealed that the lowest inoculum gave the best growth pattern. This inoculum yielded a population doubling time of less than 12 h for 4 days, a high peak density of 7 × 106 parasites/ml and the most gradual decline compared to the other 2 inocula. Rosetting epimastigotes and nests of amastigotes were observed in close association with the feeder layer cells. Epimastigotes were the most predominant form in culture supernatants but other morphological forms observed included trypomastigotes and sphaeromastigotes.
Evidence for Regular Sporulation by Haplosporidium nelsoni (MSX) (Ascetospora; Haplosporidiidae) in Spat of the American Oyster, Crassostrea virginica
Authors: BARBER ROBERT D. , KANALEY SHEILA A. , FORD SUSAN E.
Published: May 2007

The spore stage of Haplosporidium nelsoni, the ascetosporan parasite causing multinucleated sphere unknown (MSX) disease in oysters, Crassostrea virginica, has been reported so rarely (≥0.01% of infected oysters) that a second host has been postulated. However, recent intensive sampling of young (≥1 year) oysters in Delaware Bay, U.S. suggests that spore formation occurs regularly in this group and that spores are produced in at least 75–85% of all infections reaching the advanced stage. Sporulation was seasonal, occurring over two to three weeks in late June/early July and again in late summer/early fall. Our data indicate that sporulation by H. nelsoni in oysters is more common than previously suspected, occurring in a segment of the host population that may not have been sufficiently sampled in the past, and that a direct life cycle should be reconsidered.
Reactivity of Monoclonal Antibodies to Species‐Specific Antigens of Entamoeba histolytica
Authors: TACHIBANA HIROSHI , KOBAYASHI SEIKI , NAGAKURA KOUICHI , KANEDA YOSHIMASA , TAKEUCHI TSUTOMU
Published: May 2007

Twenty monoclonal antibodies were produced against trophozoites of Entamoeba histolytica strains HK‐9 and HM‐1: IMSS. When reactivity to various enteric protozoa was examined by an indirect fluorescence antibody test, 15 of the monoclonal antibodies were strongly reactive with E. histolytica trophozoites. Species‐specific antigens recognized by these monoclonal antibodies were located on the plasma membrane, nucleus, cytoplasm, and cytoskeletal structures of the trophozoites. Two of the remaining five monoclonals reacted strongly with trophozoites of the E. histolytica‐like Laredo strain. The determinant antigen was located in the cytoplasm. The three remaining monoclonal antibodies were found to recognize cross‐reactive antigens between E. histolytica and E. histolytica‐like Laredo, E. hartmanni, E. coli, Dientamoeba fragilis, Giardia lamblia, and Trichomonas hominis. These three antibodies were also reactive with T. vaginalis
Cortical and Nuclear Events During Cell Division and Resting Cyst Formation in Colpoda inflata
Authors: MARTIN‐GONZALEZ ANA , BENITEZ LAURA , GUTIERREZ JUAN CARLOS
Published: May 2007

Nuclear and cortical phenomena during dividing and resting cyst formation of Colpoda inflata are described. Cell division forms a cyst and produces two or four tomites. In each tomite, the right oral field results from the proliferation of the anterior extreme of a single kinety, and the left oral field results from the proliferation of four, five, or six somatic kineties. After macronuclear division, each macronuclear mass undergoes a chromatinic extrusion process. During resting cyst formation, the oral infraciliature of the vegetative cell is resorbed. The somatic kineties dispose in a radial way and some pairs of kinetosomes disappear. As in cell division, there is an extrusion process. From these results we conclude that the resting cysts of Colpoda inflata cannot be included in any group of the previous classifications for hypotrich resting cysts. Thus, we propose a new additional group to Walker and Maugel's classification called PKR (partial‐kinetosome‐resorbing) cysts.
Involvement of 14‐nm Filament‐Forming Protein and Tubulin in Gametic Pronuclear Behavior during Conjugation in Tetrahymena
Authors: TAKAGI IBUKI , NUMATA OSAMU , WATANABE YOSHIO
Published: May 2007

We have studied in detail the immunofluorescence localizations of Tetrahymena 14‐nm filament‐forming protein (49‐kDa protein) in relation to tubulin in conjugating wild‐type Tetrahymena thermophila (B strain) pairs and in pairs between B strain and star strains with defective micronuclei. The results suggest that germ nuclear behavior during conjugation may involve the following cytoskeletal structures: (1) during meiosis, microtubule structures are involved in micronuclear elongation and meiotic division; (2) at the postmeiotic stage, 49‐kDa protein network structures that are formed independently of the existence of pronuclei are involved in the selection and the survival of one of four meiotic products; (3) during the third prezygotic division, gametic pronuclear transfer, and zygote formation, a cytoskeletal structure in which the 49‐kDa protein colocalizes with microtubules and which is dependent on the existence of a normal gametic pronucleus is involved in gametic pronuclear behavior, and (4) during the postzygotic divisions, the microtubules are involved in nuclear behavior.
Purification and Substrate Specificity of Two Cysteine Proteinases of Giardia lamblia
Authors: WERRIES ECKHARD , FRANZ ALFRED , HIPPE HOLGER , ACIL YAHYA
Published: May 2007

The proteinase activity present in homogenates of trophozoites of Giardia lamblia, active on azocasein and urea‐denaturated hemoglobin, was separated into two different enzymes by a series of purification procedures. These procedures included gel filtration on Fractogel TSK HW‐55 (F), organomercurial agarose affinity chromatography, and ion exchange chromatography on DEAE‐cellulose. By chromatography on Sephadex G‐100, two purified enzymes exhibited relative molecular weights of Mr= 95,000 and 35,000 ± 10%, respectively. On the basis of inhibition by thiol reagents and abrogation of this effect by dithiothreitol and cysteine, they were identified as cysteine proteinases. Proteinase I (Mr= 95,000) and proteinase II (Mr= 35,000) were active against the β‐chain of insulin releasing characteristic fragments. However, differences in substrate specificities of the two enzymes could be observed by using synthetic peptides that represent sequences 1–6, 8–18, and 20–30 of the insulin β‐chain. Furthermore, the synthetic tetrapeptides Arg‐Gly‐Phe‐Phe, Arg‐Gly‐Leu‐Hyp, and Arg‐Arg‐Phe‐Phe were hydrolyzed by the two proteinases releasing Phe‐Phe and Leu‐Hyp, respectively. Compared with Arg‐Gly‐Phe‐Phe, the rates of hydrolysis of Arg‐Gly‐Leu‐Hyp and Arg‐Arg‐Phe‐Phe at substrate concentrations of 1 mM were 91% and 63% (proteinase I) and 80% and 57% (proteinase II), respectively.
Three‐Dimensional Reconstruction of Rabbit‐Derived Pneumocystis carinii from Serial‐Thin Sections II: Intermediate Precyst
Authors: PALLUAULT FRANCOIS , PIETRZYK BRUNO , DEI‐CAS EDUARDO , SLOMIANNY CHRISTIAN , SOULEZ BENOIT , CAMUS DANIEL
Published: May 2007

Three‐dimensional reconstruction of a binucleate intermediate precyst of Pneumocystis carinii was performed from serial‐thin sections using the CATIA (Conception Assistée Tridimensionnelle Inter Active) Dassault system program. The presence of a mitochondrion, complex well‐developed endoplasmic structures, and numerous Golgi vesicles was established. A better understanding of the ultrastructure of rabbit‐derived P. carinii stages made it possible to formulate hypotheses on the evolution and physiology of the endomembrane system. Thus, the presence of the well‐developed endoplasmic saccular structure and more than 230 Golgi vesicles in its vicinity might be implicated in the differentiation of the parasite surface structures and might also be related to nuclear division and individualization of intracystic bodies.
Evolution of Amitosis of the Ciliate Macronucleus: Gain of the Capacity to Divide
Authors: ORIAS EDUARDO
Published: May 2007

Ciliates exhibit nuclear dimorphism, i.e. they have a germline micronucleus and a somatic macronucleus. Macronuclei are differentiated from mitotic sisters of micronuclei. The macronuclei of “higher ciliates” are polyploid and divide acentromerically (“amitotically”); they differentiate once per life cycle. By contrast, Karyorelict (KR) ciliate macronuclei are nearly diploid and cannot divide; they must differentiate at every cell cycle. Diverse lines of evidence are presented to support the hypothesis that ancestral ciliate macronuclei were incapable of division (as in living karyorelict ciliates) and that higher ciliates gained, perhaps independently more than once, the ability to divide the macronucleus. Selective pressures that could have driven the evolution and macronuclear division and two plausible step‐wise pathways for the evolution of macronuclear division are proposed. These hypotheses are relevant to our understanding of amitosis mechanisms, evolution of nuclear dimorphism, and phylogenetic classification of ciliates.
A Test for Genetic Exchange in Mixed Infections of Leishmania major in the Sand Fly Phlebotomus papatasi
Authors: PANTON LINDSEY J. , TESH ROBERT B. , NADEAU KARI C. , BEVERLEY STEPHEN M.
Published: May 2007

We tested if genetic exchange was observable between two strains of Leishmania major (Trypanosomatidae) during mixed infection of the sand fly Phlebotomus papatasi. Previous studies suggested that genetic exchange may occur in natural populations of Leishmania at a low frequency, but experimental crosses examining small numbers of progeny (<60) did not reveal hybrid parasites. Accordingly, a strategy was devised to increase the number of progeny that could be screened by 100‐fold. Clonal derivatives from two strains that were infective to flies and contained numerous restriction fragment length polymorphisms were characterized and selected for resistance to methotrexate or tunicamycin by gene amplification. A successfully mixed infection of P. papatasi was obtained, and a method was developed for directly plating promastigotes from the gut contents of infected flies onto selective media. Twenty‐five hundred independent progeny were scored for the presence of both drug resistance markers. No hybrid parasites were observed, indicating that the frequency of genetic exchange in this cross must be less than 4 times 10‐4. The lines and methods established in this work may prove useful in future studies of the mechanism and frequency of gene exchange in Leishmania.
Effects of Osmotic Pressure on the Oxidative Metabolism of Leishmania major Promastigotes
Authors: BLUM J. JOSEPH
Published: May 2007

Leishmania major promastigotes were washed and resuspended in an iso‐osmotic buffer. The rate of oxidation of 14C‐labeled substrates was then measured as a function of osmolality. An acute decrease in osmolality (achieved by adding H2O to the cell suspension) caused an increase in the rates of 14CO2 production from [6‐14C]glucose and, to a lesser extent, from [1, (3)‐14C]glycerol. An acute increase in osmolality (achieved by adding NaCl, KCl, or mannitol) strongly inhibited the rates of 14CO2 production from [1‐: 14C]alanine, [1‐14C]glutamate, and [1, (3)‐14C]glycerol. The rates of 14CO2 formation from [1‐14C]laurate, [1‐14C]acetate, and [2‐14C]glucose (all of which form [1‐14C]acetyl CoA prior to oxidation) were also inhibited, but less strongly, by increasing osmolality. These data suggest that with increasing osmolality there is an inhibition of mitochondrial oxidative capacity, which could facilitate the increase in alanine pool size that occurs in response to hyper‐osmotic stress. Similarly, an increase in oxidative capacity would help prevent a rebuild up of the alanine pool after its rapid loss to the medium in response to hypo‐osmotic stress.
Gas Vacuoles and Flotation in the Testate Amoeba Arcella discoides
Authors: OGDEN COLIN G.
Published: May 2007

The natural formation of gas vacuoles as a method of movement is described for the testate amoeba Arcella discoides. These vacuoles are used to float the organism from the substrate to the surface in an inverted position.
The Fine Structure of Saprodinium dentatum Lauterborn, 1908 as a Representative of the Odontostomatida (Ciliophora)
Authors: SCHRENK HANS‐GÜNTHER , BARDELE CHRISTIAN F.
Published: May 2007

The fine structure of the sapropelic ciliate Saprodinium dentatum is described based on phase‐contrast microscopy, silver‐staining techniques, cryo‐fracture scanning electron microscopy, and thin sections. The study concentrates on a detailed analysis of the somatic cortex and the oral ciliature of this highly asymmetric, laterally compressed ciliate. The cell shape is dominated by a number of site‐specific spines and the curving course of 10 somatic kineties (SK 1–10). The SK, composed of dikinetids, show an intrakinety differentiation that seems characteristic for other odontostomes as well. The anterior segment of the SK is mostly ciliated, followed by a non‐ciliated segment in which the kinetosomes lack all typical fiber systems. Except for SK 4–6, the posterior segment is ciliated again, forming the spine kinetics associated with particular caudal spines. The anterior segment of SK 3 through SK 7 form the frontal band, which together with the two frontal kineties constitutes the main locomotory organelle for a ciliate that creeps on the substratum. A short kinety with inverse polarity, not seen in earlier light microscopical studies, was observed near the oral spine. We made particular effort to find a logical explanation for the observed association of the SK with the various caudal spines. The oral ciliature consists of nine adoral organelles located in a tripartite oral cavity. The absence of a paroral ciliature together with the position of the cytostome anterior to the adoral organelles may be the result of rotational movement of the oral apparatus during the evolution of these bizarre ciliates. Results are discussed with special reference to the phylogenetic relationship of the Odontostomatida to the Heterotrichida and no conclusive answer was found in this first electron microscopical study of an odontostomatid ciliate.
Microfilum Lutjani N. G. N. Sp. (Protozoa Microsporida), A Gill Parasite of the Golden African Snapper Lutjanus Fulgens (Valenciennes, 1830) (Teleost Lutjanidae): Developmental Cycle and Infrastructure
Authors: FAYE NGOR , TOGUEBAYE BHEN S. , BOUIX GEORGES
Published: May 2007

ABSTRACT Microfilum lutjani n. g., n. sp. (Microsporida) was found on the gill filaments of Lutjanus fulgens (Teleost) inhabiting the coasts of Senegal. This microsporidium forms xenomas distinguished by the microvilli covering the plasma membrane. At all stages of development individuals have isolated nuclei and are in direct contact with the host cytoplasm. Merogony is binary and sporogony is tetrasporoblastic. the spore (4.75 times 2.60 μm)) is characterized by a manubrium inserted on a laterally offset anchoring disc and extending into a very short, noncoiled polar filament (no longer than 500 nm) in the form of a hook. This type of polar filament has not been described previously in the Microsporida.
Structural and Functional Characterization of Paramecium Dynein: Initial Studies
Authors: LARSEN JØRGEN , BARKALOW KURT , HAMASAKI TOSHIKAZU , SATIR PETER
Published: May 2007

ABSTRACT Dynein arms and isolated dynein from Paramecium tetraurelia ciliary axonemes are comparable in structure, direction of force generation, and microtubule translocation ability to other dyneins. In situ arms have dimensions and substructure similar to those of Tetrahymena. Based on spoke arrangement in intact axonemes, arms translocate axonemal microtubules in sliding such that active dynein arms are (‐) end directed motors and the doublet to which the body and cape of the arms binds (N) translocates the adjacent doublet (N+1) upward. After salt extraction, based on ATPase activity, paramecium dynein is found as a 22S and a 14S species. the 22S dynein is a three‐headed molecule that has unfolded from the in situ dimensions; the 14S dynein is single headed. Both dyneins can be photocleaved by UV light (350 nm) in the presence of Mg2‐, ATP and vanadate; the photocleavage pattern of 22S dynein differs from that seen with Tetrahymena. Both isolated dyneins translocate taxol‐stabilized, bovine brain microtubules in vitro. Under standard conditions, 22S dynein, like comparable dyneins from other organisms, translocates at velocities that are about three times faster than 14S dynein.
Costal Strip Accumulation and Lorica Assembly In the Marine Choanoflagellate Diplotheca Costata Valkanov
Authors: JACKSON SEAMUS M. , LEADBEATER BARRY S. C.
Published: May 2007

ABSTRACT The lorica of the tectiform choanoflagellate D. costata contains five categories of costal strips distinguishable from each other on the basis of morphology and patterning. Categories of strips include those forming the anterior transverse costa; the anterior, intermediate, and posterior costal strips, respectively, of the longitudinal costae and those constituting the posterior transverse costa. the distinctive morphology of each class of strips makes it possible to observe their location and orientation within the overall accumulation of strips at the top of the parent cell collar. In Diplotheca costata the orientation and positioning of the different categories of strips in an accumulation anticipates their orientation and imbrication in the mature lorica. Assembly of the lorica from an accumulation of strips involves lateral sliding of costal strips to constitute transverse costae and longitudinal sliding of strips to constitute longitudinal costae. the motive force for lorica assembly is provided by extension of the anterolateral tentacles.
Efficient Expression of the Paramecium Calmodulin Gene in Escherichia coli after Four TAA‐to‐CAA Changes through a Series of Polymerase Chain Reactions
Authors: KINK JOHN A. , MALEY MARGOT E. , LING KIT‐YIN , KANABROCKI JOSEPH A. , KUNG CHING
Published: May 2007

We have expressed the Paramecium calmodulin gene in Escherichia coli by changing the four TAA codons in this gene to CAAs. This was carried out by three polymerase chain reactions (PCRs) and then cloning the product into the expression vector pKK223‐3 immediately downstream of its trp‐lac hybrid promoter. JM109 strain of E. coli, transformed with the recombinant plasmid harboring the altered Paramecium calmodulin gene, produces a protein judged to be calmodulin. It is recognized by a monoclonal antibody to Paramecium calmodulin; it migrates with the native protein at nearly the same rate in electrophoreses; and it shows a Ca2+‐dependent shift in electrophoretic pattern. The production of calmodulin is about 170 times as efficient with E. coli as with Paramecium in terms of unit volume of packed cells, and is about 400 times as efficient in unit volume of liquid culture. This method appears useful in site‐directed mutageneses and in the heterologous productions of other ciliate proteins. A critique of this method is provided. A calmodulin half‐molecule, a by‐product of this project, is described.
Structural Alteration of the Plasma Membrane in Spores of the Microsporidium Nosema algerae on Germination1
Authors: UNDEEN ALBERT H. , FRIXIONE EUGENIO
Published: May 2007

The fine structure of the plasma membrane in spores of the microsporidium Nosema algerae, a pathogen of mosquitoes, was examined in the resting condition and after the spores were stimulated to germinate in vitro. Slow penetration of resin caused collapse of the germinated spores. Thin sections of germinated spores showed peculiar membrane infoldings that were never found in ungerminated samples. Analogous germination‐dependent configurations of the plasma membrane were observed in freeze‐fractured preparations of spores either fixed and impregnated with glycerol prior to freezing, or rapidly frozen with liquid propane while in the process of germination. In every case, the replicas presented germinated spores with indentations in the protoplasmic face of the plasma membrane, and apparently complementary blunt spines on the external face, that were absent in ungerminated spores. It suggests that these alterations of the plasma membrane result from a structural adjustment to a spontaneous contraction of the spore case after germination. We discuss this interpretation with regard to conflicting views on the nature of such morphological features.
Life Cycle of Paramecium bursaria Syngen 1 in Nature
Authors: KOSAKA TOSHIKAZU
Published: May 2007

ABSTRACT. Studies were completed on the natural population density of Paramecium bursaria syngen 1 and on the life cycle stages to which the individuals belonged. Green paramecia were collected from two streams once every 20 days for over one year: 413 individuals on 26 collection dates in Mikumarikyo stream and 83 individuals on 23 collection dates in Momijidani‐gawa stream. Individuals in nature did not maintain at a steady density but fluctuated greatly depending on the month. It seems that conjugation occurred from April to June in the Mikumarikyo stream and from May to June in the Momijidani‐gawa stream. The appearance of individuals with mating ability might be related closely to increasing population so that sexual reproduction probably occurred near the peak of the population density. The 413 individuals from Mikumarikyo stream were examined to determine their position within the life cycle; 309 (74%) were immature, 55 (13%) were adolescent, and 49 (12%) were mature. No senile individuals were observed. The fraction of individuals with mating ability was generally less than 30% at any collection. Four mating types were observed occurring with about equal frequencies in mature individuals. The results show the frequencies of the recessive genes for mating types (a and b) are higher than for dominant genes (A and B). Of 83 individuals from Momijidani‐gawa stream, 44 (52%) were immature, 21 (25%) were adolescent, and 18 (21%) were mature. Again, no senile individuals were observed. Because only two mating types were found, II and III (genotypes aaB‐ and aabb), it seems possible that the dominant gene A was rare or absent in the Momijidani‐gawa population.
A Reexamination of the Ultrastructure of Didinium nasutum and a Reanalysis of the Phylogeny of the Haptorid Ciliates
Authors: LIPSCOMB DIANA L. , RIORDAN GAVIN P.
Published: May 2007

ABSTRACT. The cilia of Didinium nasutum are restricted to two girdles encircling the cell. Each row of cilia in both girdles is made up of two to three anterior pairs of kinetosomes followed by several single kinetosomes. Each single kinetosome has two sets of transverse microtubules, an overlapping postciliary microtubular ribbon, and a laterally directed kinetodesmal fiber. The pairs of kinetosomes are homologous to the oral dikinetids of other haptorians: the nonciliated kinetosome of the pair has a transverse microtubular ribbon that extends to line the membrane of the proboscis, a single short postciliary microtubule, and a nematodesma; the ciliated kinetosome has a ribbon of postciliary microtubules and two sets of transverse microtubules. The presence of these characters in Didinium invalidates Leipe & Hausmann's conclusion that the Didiniidae should be removed from the subclass that contains the other haptorians (Leipe, D. D. & Hausumann, K. 1989. Somatic infraciliature of the haptorid ciliate Homalozoon vermiculare (Kinetofragminophora, Gymnostomata) Ditransversalia n. subcl. and phylogenetic implications. J. Protozool., 36:280–289). In light of this, the justification for a subclass Ditransversalia is challenged and shown to be unnecessary.
Redefinition of the Genera Diophrys and Paradiophrys and Establishment of the Genus Diophryopsis N. G. (Ciliophora, Hypotrichida): Implication for the Species Problem
Authors: HILL BRUCE F. , BORROR ARTHUR C.
Published: May 2007

ABSTRACT. Species belonging to the genus Diophrys Dujardin, 1841, are easily recognized due to possession of the usual complement of approximately seven frontoventral cirri, five transverse cirri, two left marginal cirri, and three large caudal cirri. Separation of these species has been based upon differences in cell length and width, the number and arrangement of cilia in dorsal kinetics, the configuration of the adoral zone of oral polykinetids, the number and distribution of cirri within cirral groups, and the number and arrangement of macronuclei. Jankowski used some of these characteristics to divide the genus into two genera, Diophrys and Paradiophrys, with several subgenera [Jankowski, A. W. 1978. Systematic revision of the class Polyhymenophora (Spirotricha), morphology, systematics and evolution. Tezisy Dokl. Zool. Inst. Akad. Nauk SSSR, 197839‐40. (in Russian); Jankowski, A. W. 1979. Systematics and phylogeny of the order Hypotrichida Stein, 1859 (Protozoa, Ciliophora). Trudy. Zool. Inst. Akad. Nauk SSSR, 86:48–85. (in Russian with English summary)]. Data obtained from light microscopic examination of stained (nigrosin‐butanol, Chatton‐Lwoff, and Protargol) cells in interphase or division supports and modifies the use of particular structural features of these ciliates for the purpose of taxonomic classification. The structural variability within and among populations of different species within the genera Diophrys (D. appendiculata, D. oligothrix, and D. scutum) and Paradiophrys (P. irmgard and P. multinucleata) is described. D. hystrix is redescribed as the type of the new genus Diophryopsis n. g. Comparative information on the cortical morphogenesis of division of selected species within each genus is reviewed. Two taxonomic classifications of these hypotrichs are discussed: 1) a listing of diagnoses and synonymies and 2) a binary key for identification of all species at the light microscope level. An alternative evolutionary explanation of variations among isolates is presented.