bluuebunny/crossref_metadata_2025 huggingface dataset:
A Multinucleated Marine Amoeba Which Digests Seaweeds1
Authors: POLNE‐FULLER MIRIAM
Published: May 2007

Marine amoebae were isolated during a search for organisms which degrade cell walls of seaweed. One of the isolates, a multinucleated amoeba (referred to here as Amoeba‐I‐7 or Am‐I‐7) was isolated from live tissues of the brown seaweed Sargassum muticum. It digested a variety of brown and red seaweeds including their walls and cuticles. Axenic clone cultures were isolated from cells that migrated on agar. Cultures were grown on agar or in liquid media. Seaweeds, seaweed wall extracts, and unicellular algae were tested as food sources.
Two Armored Dinoflagellates from the Southwestern Atlantic Ocean: A New Species of Protoperidinium and a First Record and Redescription for Gonyaulax alaskensis Kofoid1
Authors: BORGESE M. BEATRIZ
Published: May 2007

This paper describes a new armored dinoflagellate, Protoperidinium dolichoporum, and updates the description of Gonyaulax alaskensis Kofoid, 1911, both from the southwestern Atlantic Ocean. The distinguishing characteristics of P. dolichoporum are the following: the globular‐pentagonal shape, a pore plate extending onto the dorsal surface, a second anterior intercalary five‐sided plate in contact with the fourth and fifth precingular plates, and an unusual body sculpture of irregular rounded papillae with 1–3 pores on the top of each. Although in general similar, this new species differs in a significant number of details from other members of the Avellana group. The original thecal formula of G. alaskensis given by Kofoid in 1911 is revised with respect to the epithecal plate pattern and the sulcal region is now described in detail. This is the first record of G. alaskensis in the southwestern Atlantic Ocean.
Adhesion, Morphology, and Locomotion of Paramoeba pemaquidensis Page (Amoebida, Paramoebidae): Effects of Substrate Charge Density and External Cations1
Authors: Martin Ronald E.
Published: May 2007

Morphology and locomotive behavior in the marine amoeba, Paramoeba pemaquidensis Page, was examined under different environmental conditions. Paramoeba requires a minimum surface negative charge density for adhesion of amoebae to substrata. Once adhesion to the substratum has been attained, however, surface negative charge density has no effect on morphology or locomotive rate. Divalent cations are not required for adhesion, but external calcium is required for normal locomotion. In the presence of calcium, Paramoeba often assumes a locomotive form with a broad, well‐developed anterior hyaline region and truncate posterior region. Locomotive forms vary from those with only a well‐developed hyaline region (Flabellula‐like) to forms with long digitiform sub‐pseudopodia (Vexillifera‐like), with intermediate morphotypes. Locomotive rates decrease and anteroposterior polarity disappears in the presence of living or heat‐killed bacteria, indicating that phagocytosis temporarily interferes with locomotion and alters form.
Some Enzyme Activities in the Testate Amoeba Netzelia tuberculata1
Authors: ANDERSON O. ROGER
Published: May 2007

ABSTRACT. Testate amoebae occur in diverse environments including well aerated streams and anoxic bottom sediments. They consume a wide variety of food including algal prey, bacteria, and detritus. Since little is known about the physiological ecology of many of these widespread organisms, some respiratory and digestive enzyme activities were assessed using Netzelia tuberculata, which is readily cultivated in the laboratory. Activities, expressed as units/μg protein are as follows: acid aryl phosphatase, 19.0 × 10−1; acid protease, 26 × 10−3; cytochrome oxidase, 2.3 × 10−4; and lactate dehydrogenase, 3.6 × 10−4. No amylase was detected in these specimens, which may help to explain why starch grains, apparently consumed from algal prey, are expelled from the cytoplasm and used as wall‐construction particles.
High‐Resolution Polyacrylamide Gradient Gel Electrophoresis (PGGE) of Isoenzymes from Five Naegleria Species
Authors: MOSS DELYNN M. , BRANDT FLOY H. , MATHEWS HENRY M. , VISVESVARA GOVINDA S.
Published: May 2007

ABSTRACT. High‐resolution polyacrylamide gradient gel electrophoresis (PGGE) was used to separate isoenzymes of 12 Naegleria strains: one N. australiensis, two N. lovaniensis, one N. jadini, two N. gruberi isolated from environmental samples, and six N. fowleri strains isolated from patients with primary amoebic meningoencephalitis. Of the eight enzymes studied, seven showed zymograms with interspecific variation that identified all the species tested. Although the six N. fowleri strains were biochemically the most homogeneous, they showed intraspecific isoenzyme variation that allowed them to be grouped into four zymodemes. The PGGE technique, which separates isoenzymes by their molecular shape, is both sensitive and economical. It offers an addition or an attractive alternative to isoelectric focusing which has commonly been used to aid species identification of Naegleria by separating isoenzymes by their isoelectric point.
Analysis of Tetrahymena Mucocyst Material with Lectins and Alcian Blue1
Authors: WOLFE JASON
Published: May 2007

ABSTRACT. There are numerous mucocysts in Tetrahymena; however, little is known about their composition, organization, biosynthesis, or function. Mucocysts of Tetrahymena are membrane‐bounded vesicles located at the cell cortex. They are torpedo‐shaped structures (0.9 μm x 0.3 μm) lined up in longitudinal rows along the surface. It is estimated here that each cell contains about 5000 mucocysts. Mucocyst contents are organized in a crystalline manner, but when that material is released by exocytosis, it swells and forms a gel. Using fluorescence microscopy, we demonstrate that mucocysts contain concanavalin A (Con A)‐binding material. First, intracellular fluorescent particles in fixed cells incubated with fluorescein‐derivatized Con A (F‐Con A) have the same distribution, shape, and orientation as mucocysts in living cells. Also, mucocysts were induced to undergo synchronous exocytosis, and the released material formed a capsule around the cell. The capsule was fluorescent after incubation with F‐Con A. In both cases fluorescence was abolished by competition with α methyl mannoside, indicating that Con A is binding specifically to a glycosidic component of the mucocyst. Mucocyst capsules also bind wheat germ agglutinin but not soybean agglutinin, pea lectin, or lentil lectin. Preparations of mucocyst material were analyzed by SDS‐PAGE. Silver stain revealed a high molecular weight band that had not previously been detected by Coomassie blue staining. That band also stained with Alcian blue, indicating that it is a mucopolysaccharide. Finally, that same band was shown to be Con A binding. Thus the Con A‐binding and Alcian blue‐staining properties of mucocysts can be attributed to the same high molecular weight mucopolysaccharide component. This study indicates that it may be possible to purify a specific carbohydrate component of mucocysts which may be helpful in analyzing their function, biogenesis, and structural organization.
Four New Species of Isospora from the Small Tree Finch (Camarhynchus parvulus) from the Galapagos Islands1
Authors: McQUISTION THOMAS E. , WILSON MARCIA
Published: May 2007

ABSTRACT. Four isosporan species are described from the small tree finch, Camarhynchus parvulus from Isabela Island on the Galapagos Archipelago. Isospora exigua n. sp. oocysts subspheroidal, one‐layered, smooth, yellow‐brown color, 20.4 × 20.1 (20‐23 × 18‐23) μm, with no micropyle, residuum, or polar body. Sporocysts ovoidal, 14 × 9.5 (13‐15 × 8‐10) μm, with small Stieda and substieda bodies and irregular‐shaped residuum. Isospora rotunda n. sp. oocysts subspheroidal, single‐layered, smooth, yellow‐brown wall with large polar body and no micropyle or residuum, 20.9 × 20.8 (20‐24 × 19‐23) μm. Sporocysts ovoidal, 15 × 9.7 (13‐16 × 9‐10) μm with knob‐like Stieda bodies, prominent substieda bodies and round residuum. Isospora fragmenta n. sp. oocysts subspheroidal with no micropyle or residuum but with many splinter‐like polar granules and a smooth, colorless, single‐layered wall, 25.3 × 24.2 (24‐27 × 23‐25) μm. Sporocysts piriform 15.4 × 11.5 (14‐17 × 11‐12) μm with knob‐like Stieda bodies, prominent substieda bodies, and irregular‐shaped residuum. Isospora temeraria n. sp. oocysts ellipsoidal with one polar body, no micropyle or residuum, and wall of a single layer, smooth, yellow‐brown color, 25.4 × 21.1 (21‐30 × 17‐23) μm. Sporocysts piriform, 15 × 10 (14‐15 × 9‐11) μm with knob‐like Stieda bodies, prominent substieda bodies, and a round residuum. One woodpecker finch, Cactospiza pallida, was found to be infected with I. exigua, and a warbler finch, Certhidea olivacea was infected with I. fragmenta.
Long Term Cryopreservation of the Amastigote Stages of Hemoflagellates
Authors: YAEGER ROBERT G.
Published: May 2007

ABSTRACT. Tissue homogenates containing amastigotes of either Leishmania donovani, L. tropica, or Trypanosoma cruzi were rapidly frozen with 10% glycerol as cryoprotectant. Viability and pathogenicity were maintained for at least 23 years with the Khartoum strain of L. donovani, 22 years with the Malakal strain of L. donovani, and 7 years for L. tropica and T. cruzi. Similar results over a shorter period of time were obtained with a slow‐freezing technique.
Freeze‐Fracture Study of the Endosymbiont of Blastocrithidia culicis1
Authors: SOARES MAURILIO JOSÉ , DE SOUZA WANDERLEY
Published: May 2007

The two unit membranes which envelope the endosymbiont of the trypanosomatid protozoon, Blastocrithidia culicis, were studied using the freeze‐fracture technique. The distribution of the intramembranous particles on both fracture faces of the inner and outer membrane of the endosymbiont was analyzed in the replicas. The protoplasmic face of the inner membrane (PFi) had a higher density of membrane particles than that observed on the extracellular face (EFi), a pattern typical of plasma membranes. The extracellular face of the outer membrane (EFo) presented a density of membrane particles much higher than that observed on the P face of the outer membrane (PFo) a distribution significantly different from that found in the inner membrane of the endosymbiont and in the plasma membrane of the protozoon, but similar to that observed in Gram‐negative bacteria. The data obtained support the idea that the endosymbiont of trypanosomatids represents a Gram‐negative bacterium‐like microorganism enveloped by two unit membranes and lacking a peptidoglycan layer and which lives in direct contact with the cytoplasm of the protozoon.
Dorsal Kinetosomal Distributions in the Ciliate Genus Euplotes1
Authors: GATES MICHAEL A.
Published: May 2007

The percentage allocations of ciliary units to each ciliary row across the dorsal surface were assessed for seven marine and five freshwater populations, representing the most commonly collected morphotypes of the genus Euplotes. In marine forms, there is a spectrum of dorsal kinetosomal distributions, within which is included the characteristic distribution for the vannus complex of sibling species. In contrast, there are only two basic ciliary patterns on the dorsal surface of the most ubiquitous freshwater “species”. The congruence between the classification of morphotypes based on dorsal ciliary patterns and that based on ventral cirral patterns is remarkable, despite the morphogenetic independence of kinetosomal structures on these two surfaces.
Freeze‐Fracture Study of Blastocystis hominis1
Authors: YOSHIKAWA HISAO , YAMADA MINORU , YOSHIDA YUKIO
Published: May 2007

The ultrastructure of Blastocystis hominis was investigated by the freeze‐fracture method. Freeze‐fracture replicas of the membranes of B. hominis and its organelles were studied with special regard to the density and distribution of the intramembranous particles (IMF's). On all membrane replicas, the concentration of IMF's on the protoplasmic face (P face) invariably was greater than on the exoplasmic face (E face). On the P face, IMP's were heterogeneously distributed in dense aggregates, alternating with particle‐free, smooth surface areas. Occasionally, small depressions and protrusions were observed in these areas. On the membrane of the central vacuole, invaginations into the vacuole were frequently observed within the smooth surface regions. Since most of the granules in the central vacuoles had no IMF's, it seems likely that the intervacuolar granules were formed from these invaginations of the vacuole membrane. The width of the intermembrane space between the inner and outer membranes of the nuclear envelope was uneven, with regions of relative narrowness interspersed with regions of expansion. Nuclear pores were localized within the narrow portions of this space. A nucleus, apparently in the process of dividing, was observed enclosed within an intact outer membrane. Division of the outer membrane would then result in the formation of two discrete nuclei.
Variation in the Growth Medium During the Culture Cycle of Tetrahymena: With Special Reference to Ammonia (NH3), Ammonium (NH4+), and pH1
Authors: LARSEN JØRGEN , SVENSMARK BO , NILSSON JYTTE R.
Published: May 2007

The ciliate Tetrahymena pyriformis was grown in a peptone medium without added glucose. The interrelationship between increasing cell density and pH of the growth medium was studied from mid‐log to the stationary phase, i.e. from 50,000 to 1,000,000 cells/ml, by continuous registration of the pH of the growth medium. The present findings correlate with the known physiological, biochemical, and structural changes occurring in Tetrahymena as it passes through the culture cycle. The ammonia production of the cells and the buffer capacity of the growth medium were determined throughout the growth cycle. The results revealed that the ammonia excreted by the cells can explain the increase in pH of the medium from 6.8 to about 8.3 normally seen during the culture cycle. Moreover, neither the increased pH nor the raised level of ammonia were found to be the responsible factor for cessation of cell proliferation in the stationary growth phase although these factors may affect cell proliferation in concentrations well beyond the range found in normal cultures.
Epulopiscium fishelsoni N. G., N. Sp., a Protist of Uncertain Taxonomic Affinities from the Gut of an Herbivorous Reef Fish1
Authors: MONTGOMERY W. LINN , POLLAK PEGGY E.
Published: May 2007

Epulopiscium fishelsoni n. g., n. sp., is described from the gut of Acanthurus nigrofuscus, an herbivorous surgeonfish (Acanthuridae: Teleostei) from the Red Sea, Israel. The symbiont is placed in the kingdom Protoctista (or Protista) but more specific taxonomic assignment is impossible at this time. The organism is of an elongate oval shape, round in cross‐section, and highly mobile, with the ability to reverse direction rapidly. It lacks a mouth or other external structures, with the exception of fine surface filaments of an undetermined nature. Internally, there is a complex of folded membranes or tubules and a nucleus. No other organelles are evident. Reproduction is characterized by doubling of nuclei within the parental cell and emergence of daughter cells from a perforation in the parental cortex. Symbionts appear to exhibit circadian cycles of growth, reproductive activity, and movement within the gut. Although the organism greatly reduces local gut pH when present in large numbers, we know nothing of interactions between host and symbiont.
Feeding and Swimming Behavior in Grazing Microzooplankton1,2
Authors: LEVANDOWSKY M. , KLAFTER J. , WHITE B. S.
Published: May 2007

ABSTRACT A random‐walk model of food‐searching behavior is considered for the microzooplankton. It is suggested that in still waters a random walk of the conventional sort, modeled by a Wiener process, is less efficient than a Levy walk (a random walk whose excursions follow a Levy distribution) with Levy parameter less than two. For Levy parameter less than one, however, little advantage is gained by further reduction. In turbulent water, on the other hand, dispersion due to a random walk is dominated by the turbulent diffusion of the medium so that the Levy parameter appears to be less important. The effect of chemosensory responses is considered. It is suggested that these are most useful in still water, whereas in turbulent water their value would be less, and a non‐specific filtering behavior might be more plausible.
Biogenic Amines Stimulate Regeneration of Cilia in Tetrahymena thermophila1
Authors: CASTRODAD FELIX A. , RENAUD FERNANDO L. , ORTIZ JULIO , PHILLIPS DAVID M.
Published: May 2007

ABSTRACT Serotonin and catecholamines affect the regeneration of cilia in Tetrahymena thermophila in a dose‐dependent manner: micromolar concentrations are stimulatory, whereas millimolar concentrations have little or no effect. This conclusion is based on motility measurements in regenerating cells and on ciliary counts in scanning electron micrographs. In addition, the recognition mechanism for each hormone appears to be specific and independent. Our results suggest an evolutionary link with hormonal mechanisms in multicellular eukaryotes.
Entamoeba histolytica: Diffuse Liver Inflammation in Gerbils (Meriones unguiculatus) with Experimentally Induced Amebic Liver Abscess
Authors: CHADEE K. , MEEROVITCH E.
Published: May 2007

The histopathological changes that occur in the uninfected liver lobes of gerbils with a localized amebic liver abscess (left lobe) were studied from 5 to 60 days after inoculation. Early parenchymal changes (10 days) in the right and median liver lobes showed a lymphocytic infiltrate and bile duct proliferation in the portal areas. Maximum alternations occurred at 20 to 30 days after inoculation and were characterized by a dense portal infiltrate, hepatocyte degeneration, granulocytic infiltrate and marked glycogen depletion. In drug‐treated infections with metronidazole, the diffuse liver inflammation was terminated. The results of this study suggest that the diffuse liver injury was directly or indirectly induced by the presence of a proliferating amebic liver abscess and that the pathology caused by amebic liver abscess is more extensive than previously thought.
Properties of Purified L‐Ornithine Decarboxylase (EC 4.1.1.17) from Tetrahymena thermophila
Authors: EICHLER WOLFGANG
Published: May 2007

Ornithine decarboxylase (ornithine carboxy lyase; EC 4.1.1.17) (ODC) from Tetrahymena thermophila was purified 6,300 fold employing fractionated ammonium sulfate precipitation, gel permeation chromatography on Sephadex G‐150, ion exchange chromatography on DEAE‐Sepharose CL‐6B, and preparative isoelectric focussing. The product obtained in 24% yield was a preparation of the specific activity of 10,200 nmol CO2mdh‐1mdmg‐1. The purified enzyme was rather stable at 37°C (14% loss of activity within 1 h). The molecular and catalytic properties of this enzyme were investigated. The isoelectric point was 5.7 and the molecular weight (MW) was estimated to be 68,000 under nondenaturing conditions. The pH optimum was between 6.0 and 7.0, the Km for the substrate L‐ornithine was 0.11 mM, and the Km for the cofactor pyridoxal 5‐phosphate was 0.12 μM; the product of ODC catalysis, putrescine, was a poor inhibitor with an estimated Ki of about 10 mM. The enzyme was inhibited competitively by D‐ornithine with a Ki of 1.6 mM and by α‐difluoromethylornithine with a Ki of 0.15 mM. The latter one, an enzyme activated irreversible inhibitor of mammalian ODC, inactivated the enzyme from T. thermophila at high concentrations with a half life time of 14 min. Other basic amino acids, e.g. L‐lysine, L‐arginine, and L‐histidine, were neither substrates nor inhibitors of the enzyme, as were the diamines 1,3‐diaminopropanol and cadaverine, the polyamines spermidine and spermine and the cosubstrate analogues pyridoxal and pyridoxamine‐5‐phosphate.

Polyanions were activators of the enzyme: The half maximal ODC stimulating concentrations were 2.2 μgmdml‐1 for RNA, 6.1 μgmdml‐1 for DNA, and 0.25 μgmdml‐1 for heparin.

These results indicate that ODC from T. thermophila shares several properties with ODC preparations from other organisms but in some respects, especially in activator and inhibitor specificity, there are some special qualities unique to this particular protozoan enzyme.
Development of Babesiosoma stableri (Dactylosomatidae; Adeleida; Apicomplexa) in its Leech Vector (Batracobdella picta) and the Relationship of the Dactylosomatids to the Piroplasms of Higher Vertebrates
Authors: BARTA J. R. , DESSER S. S.
Published: May 2007

The sporogonic and merogonic development of Babesiosoma stableri Schmittner & McGhee, 1961 within its definitive host and vector, a leech Batracobdella picta (Verrill, 1872), was studied by light and electron microscopy. Gamonts released from frog erythrocytes in the blood meal of the leech associated in syzygy and fused; the gamonts were isogamous and only 1 microgamete was formed. The ultrastructural appearance of the resulting zygote was similar to that of the gamonts, but it was larger. The zygote had an apical complex (including a polar ring, conoid and 2 pre‐conoidal rings and micronemes, but no recognizable rhoptries), triple‐membraned pellicle, about 40 subpellicular microtubules and prominent stores of amylopectin. Zygotes penetrated the cells of the intestine and underwent sporogony directly within the cytosplasm of the ieech epithelial cell without the formation of a parasitophorous vacuole. Eight sporozoites budded simultaneously around the periphery of an irregularly shaped oocyst. No oocyst wall was formed. Each sporozoite had a complete apical complex (including rhoptries), abundant amylopectin inclusions and a triple‐membraned pellicle with about 32 subpellicular microtubules. The sporozoites initiated merogonic replication primarily within the salivary cells of the leech although other tissues, such as muscle, were infected. Each meront produced 4 merozoites by simultaneous budding, forming a cruciform meront typical of the intraerythrocytic development of this parasite. The meront was located directly within the cytoplasm of the host cell. Merozoites, with abundant amylopectin, had a complete apical complex and triple‐membraned pellicle with about 40 subpellicular microtubules. The merozoites either initiated a further cycle of replication, or they moved into the ductules of the leech salivary cells which extend to the tip of the proboscis. Observations on gametogenesis. syngamy and sporogony of B. stableri in its leech host indicate that the family Dactylosomatidae should be placed in the suborder Adeleina (Eucoccidiida: Apicomplexa). Babesiosoma stableri was transmitted to uninfected frogs (Rana spp.) by the bite of infected leeches. Prepatent periods ranged from 26 to 38 days at 25° C. Despite a directed search in laboratory reared tadpoles which had each been injected intraperitoneally with 150,000 merozoites, no pre‐erythrocytic developmental stages were observed. Similarities in their biology suggest close phylogenetic affinities of the dactylosomatids, and other adeleid blood parasites, with the piroplasms of higher vertebrates.
Immunoassay Comparison of Haplosporidan Spores from Teredo navalis and Haplosporidium nelsoni Spores from Crassostrea virginica
Authors: McGOVERN ELIZABETH ROBINSON , BURRESON EUGENE M.
Published: May 2007

Spores of a haplosporidan infecting Teredo navalis Linnaeus have been described as morphologically indistinguishable from spores of Haplosporidium nelsoni. To test the hypothesis that these organisms are conspecific, a colloidal gold immunoassay was used to compare antigenic characteristics of the spores from both hosts. Rabbit antibody to formalin‐fixed spores from T. navalis was tested against paraffin sections of Crassostrea virginica infected with spores of H. nelsoni and against paraffin sections of infected 7″. navalis. Application of primary antibody was followed by addition of affinity purified goat anti‐rabbit IgG coaled on 5‐nm colloidal gold particles. The reaction was enhanced by precipitation of metallic silver; a positive reaction appeared as a dark brown to black signal at the site of each antigen‐antibody complex. Haplosporidium nelsoni spores did not react when assayed with the antibody made to spores from T. navalis. Spores from infected T. navalis tissue reacted positively with rabbit antibody. This result indicates that the spores from the 2 hosts are antigenicaliy distinct and suggests that they are different species.
The Fine Structure of Secretion by Plasmodium knowlesi Merozoites during Red Cell Invasion
Authors: BANNISTER L. H. , MITCHELL G. H.
Published: May 2007

The secretory organelles of Plasmodium knowlesi were studied ultrastructurally to examine their mode of action during invasion. The formation of lamellar structures in merozoite rhoptries within late stage schizonts is prevented by the protease inhibitors chymostatin and leupeptin. Under normal conditions vesicles lined by 6‐nm membranes are formed in rhoptries during erythrocyte invasion. Stereoscopic viewing of tilted sections shows that where the merozoite apex contacts the parasitophorous vacuole (PV) membrane during invasion, a domed elevation of the PV surface lies within the mouth of the rhoptry duct in contact with the secretory matrix. The membrane of the early invasion pit is thinner (6 nm) than the red cell membrane elsewhere, and sheets of lamellar material are frequently present on the invasion pit surface. These findings support the proposal that the rhoptry‐microneme complex is capable of generating membranous material and inserting it into the red cell surface in a controlled manner to create the parasitophorous vacuole. On the basis of this model, measurements from serial sections show that the rhoptries could provide enough material to create a membrane lining the parasitophorous vacuole, and, with the contribution of the microspheres, could double it to accommodate the early ring stage of the parasite.
Analysis of Paramecium Macronuclear DNA Using Pulsed Field Gel Electrophoresis
Authors: PHAN HUAN L. , FORNEY JAMES , BLACKBURN ELIZABETH H.
Published: May 2007

.We have analyzed the macronuclear DNA of Paramecium tetraurelia using orthogonal‐field‐altemation gel electrophoresis. The mean size of the linear macronuclear DNA molecules is approximately 450 kb. Less than 6% of the macronuclear DNA is larger than 800 kb. Using pulse times of 20, 40, 60 and 90 s we show that the macronuclear fragment containing the A type variable surface antigen gene migrates reproducibly as a 320‐kb linear DNA. Over the same pulse times we describe the unusual migration of the ribosomal RNA gene (rDNA) of P. tetraurelia. At pulse times of 20 and 40 s the rDNA migrates at limit mobility (300 and 500 kb, respectively) whereas with 60‐ and 90‐s pulse times, 2 components of rDNA are observed; 1 fraction independent of pulse time migrating at limit mobility, and a 2nd component migrating between 100‐kb and 400‐kb linear markers. Based upon previous electron micrographic studies of Paramecium rDNA as well as data presented here we conclude that the majority of Paramecium rDNA molecules are a circular DNA form.
Trypanosoma theileri Associated with T‐lymphocytes Isolated from a Latently Infected Cow
Authors: GRIEBEL PHILIP J. , GAJADHAR ALVLN A. , BABIUK LORNE A. , ALLEN JOHN R.
Published: May 2007

.Trypanosoma theileri infection, latent in a mature Hereford cow, could not be demonstrated in routine blood smears or cultures. Throughout the 2‐year period an intravenous injection of dexamethasone consistently produced parasitaemia which was detectable in peripheral blood mononuclear cell (PBMC) cultures. Fractionation techniques such as plastic adherence and Sephadex‐G10 fractionation, designed to deplete monocytes and enrich T‐lymphocytes, increased trypanosome‐positive cultures from 25 to 100%. Removal of B‐lymphocytes from Sephadex, non‐adherent (SE‐NA) cells did not reduce the percentage of positive cultures. Light and transmission electron microscopy of SE‐NA PBMC cultured for 36 or 45 h revealed numerous trypanosomes and widespread T‐lym‐phocyte destruction. No trypanosomes were observed in 12‐h cultures. A close association, either extra‐ or intracellular, of a parasitic stage of T. theileri with T‐lymphocytcs is inferred.
Differentiation, Multiplication and Control of Bloodstream Form Trypanosoma (Duttonella) vivax in Mice
Authors: MAHAN S. M. , BLACK S. J.
Published: May 2007

.The growth and differentiation of Trypanosoma vivax was studied in intact and irradiated C3H/He and C57B1/6 mice. In irradiated (800 R) or intact C3H/He and irradiated (800 R) C57B1/6 mice, T. vivax parasitaemia increased rapidly then entered a plateau phase and thereafter declined in an antibody‐independent remission phase. Throughout the infection, variations were observed in parasite morphology, density, DNA content, number of organisms with 2 nuclei and 2 kinetoplasts and infectivity of parasites for mice. Parasites in exponential phase had the highest number of members in the S, G2 and M phases of the cell cycle as determined by staining with the interchalating dye Chromomycin A, and analysis on a flow cytometer. During this phase there were numerous parasites with 2 nuclei and 2 kinetoplasts and infectivity was high for mice. As the parasitaemia approached and entered the plateau phase, the proportion of organisms in the S, G2 and M phases of the cell cycle as well as the number of those with 2 kinetoplasts decreased slightly; the number of organisms with 2 nuclei decreased rapidly; and parasites had a considerably reduced capacity to infect mice. Organisms from the remission phase contained only 1 nucleus and 1 kinetoplast and were not infective for mice. The study suggests that T. vivax organisms transit from dividing to committed non‐dividing forms and that some non‐dividing, non‐infective T. vivax organisms remain trapped in the S, G2 and M stages of the cell cycle and die without completing binary fission. In contrast to the above, parasite wave remission occurred in T.vivax‐infected intact C57B1/6 mice during exponential growth when there were large numbers of dividing form organisms present in the bloodstream as determined by both DNA content and the proportion of parasites with 2 kinetoplasts and 2 nuclei. Clearance of T. vivax from the bloodstream of infected intact C57B1/6 mice coincided with the production of a parasite‐specific antibody response. The studies are discussed with reference to the mode of induction of host protective antibody responses to exponentially growing T. vivax.
5S Ribosomal RNA Sequence of Pneumocystis carinii and its Phylogenetic Association with “Rhizopoda/Myxomycota/Zygomycota Group”
Authors: WATANABE JUN‐ICHI , HORI HIROSHI , TANABE KIYOKATSU , NAKAMURA YOSHIKAZU
Published: May 2007

The cytoplasmic 5S ribosomal RNA sequence from Pneumocystis carinii was determined and compared with those of 382 eukaryotes and an evolutionary tree was constructed to establish the phylogenetic position of Pneumocystis. The data suggest that Pneumocystis is associated with the Rhizopoda/Myxomycota/ Zygomycota group but not with common fungi, such as Ascomycota or Basidiomycota, nor with other protozoa.
Propagation and Purification of Rat Pneumocystis carinii in Short‐Term Cell Culture
Authors: ARMSTRONG MARTINE Y.K. , RICHARDS FRANK F.
Published: May 2007

ABSTRACT. A short‐term cell culture is used to propagate and purify rat‐derived Pneumocystis carinii (Pc). An aliquot of pelleted material washed out of the lungs of rats with moderate to severe Pc pneumonia is cultured for 7 to 10 days on the adherent mink lung cell line Mv I Lu, and the rest of the material is frozen down in medium with 10% glycerol. Although it has not been established that substantial multiplication of Pc occurs in culture, the Pc organisms harvested from the supernatant at the end of the culture period are relatively free of both host and feeder cells. This is in marked contrast with the lung wash inoculum in which the Pc organisms are heavily contaminated with rat cells and enmeshed in a highly sticky material. Lung wash preparations frozen down in glycerol and stored at −70° C for as long as 6 months or more can be successfully cultured upon thawing with no apparent loss of viability of the Pc organisms.
Proliferation of Pneumocystis Trophozoites in Human Lymph Nodes and in Nude Mice Lungs
Authors: MATSUMOTOL YOSHITSUGU , AIKAWA JACOB K. FRENKEIA MASAMICHI , YOSHIDA YUKIO
Published: May 2007

Pneumocystis infection in athymic nude mice lungs showed a particularly high trophozoite to cyst ratio. A similar observation was obtained from a study of a patient with lymph node infection with Pneumocystis. Eosinophilic foamy masses in these sites were observed by light microscopy . With the electron microscope, the masses were seen to be composed of large aggregates of trophozoites. Cystic forms (precyst, cyst and empty cyst) were extremely scarce in comparison with the huge numbers of trophozoites. These cystic forms were mostly undergoing degeneration. These observations indicate that the mode of proliferation in both situations was predominantly asexual, that is, proliferation by trophozoites, suggesting that certain conditions may enhance asexual reproduction or depress the formation of cysts.
Pneumocystis Antigen Appearance during Immunosuppression
Authors: DOWNS M.H. IVEY.T.A. , HART M.C. , GRAVES D.C.
Published: May 2007

The sequential appearance of Pneumocystis carinii (Pc) antigens during the progression of immunosuppression in rats was studied using the immunoblotting technique and specific immunologic probes. Putative Pc soluble antigens, with molecular weights of approximately 70 and 90 kd, were detected as early as 2 wk after initiation of immunosuppression in rats using a pool of monoclonal antibodies produced to Pc isolated from lungs using enzymatic digestion. Monoclonal antibodies produced to Pc isolated by massaging the lung tissue using a Stomacher apparatus and infecuon‐derived sera did not detect soluble antigens until at least the 6lh wk of immunosuppression. Analysis of Pc pellets obtained from Stomacher‐ and lavage‐processed lungs revealed that the lower molecular weight antigens ( 40, 45 and possibly 55–60 kd) were recognized early during the immunosuppression process.
Ultrastructural Study of Pneumocystis carinii in Explant Cultures of Rabbit Lung and in Cultures with and without Feeder Cells
Authors: DEI‐CAS EDUARDO , SOULEZ BENOIT , CAMUS DANIEL , WATTEZ A. , HERBAUT J.
Published: May 2007

Pneumocystis carimV‐parasitized lung explains were obtained from corticoid‐lrealed rabbits and maintained in vitro. Twenty‐one days after the beginning of explant cultures, the ultrastructural morphology of trophozoite, precyst and cyst forms was normal as compared to the in vivo ul‐trastructure of P. carinii from infected rabbit. However, after the 36th day, only altered forms of P. carinii were observed. Lung tissue showed only minor alterations. Intracyloplasmic lamellar inclusions were observed in type 2 alveolar cells from which they were released. While the total number of parasites increased approximately 4‐fold from day 0 to day 41, trophozoite counts increased approximately 6 times. Pneumocystis cells from inocula and supemaies of cultures with and without Vero cells showed important ultrastructural alterations.
Analysis of a Surface Antigen of Pneumocystis carinii
Authors: LINKE MICHAEL J. , WALZER PETER D.
Published: May 2007

The 115 kd band in polyacrylamide gels is a major antigen of Pneumocystis carinii. Data obtained from treatment with enyzmes, binding to lectins, and labelling the surface with biotin suggest that this moiety is a glycoprotein containing mannosyl/glucosyl and N‐acetylglucosamine residues, and that it is located on the cell wall of the organism. Other rat and human P. carinii antigens also are glycoproteins but differ in specific protein or carbohydrate residues or location on the organism.
Lectins as Probes to Pneumocystis carinii Surface Glycocomplexes
Authors: DE STEFANO J. A. , CUSHION M. T. , TRINKLE L. S. , WALZER P. D.
Published: May 2007

The binding characteristics of a panel of commercially available hi lC‐conjugated lectins to Pneumocystis carinii (Pc) were assessed by fluorescence microscopy and flow cytometry. Rat Pc obtained from infected lung homogenates were incubated with FTTC‐conjugated lectins in a series of concentrations, counterstained with propidium iodide, and analyzed for percent fluorescence and fluorescence intensity. All organisms bound concanavalin A and Wisteria floribunda agglutinin, 2 representatives of the glucose/mannose‐binding group. From the lectin group specific for N‐acetylglucosamine, Pc reacted more strongly with wheat germ agglutinin than with Solanum tuberosum agglutinin or Griffonia simplicifolia II lectin. Pneumocystis treated with lectins specific for N‐acetyl‐D‐galactosamine and galactose exhibited much variation; the cells reacted moderately well to soybean agglutinin and less to Bauhinia purpurea, Madura pomifera and Dolichos biflorus agglutinins and Giffonia simplicifolia I lectin. Arachis hypogaea agglutinin, Viscum album agglutinin and Griffonia simplicifolia 1‐β4 lectin had not effect. The organisms reacted weakly with Ulex europeus 1 agglutinin which is specific for fucose and did not react with Limax flavus lectin, which is specific for sialic acid. Competitive inhibition studies using relevant carbohydrates were performed to indicate that the positive reactions were specific. These studies should help to elucidate the mechanisms of attachment and pathogenesis of this organism.
Treatment of Experimental Pneumocystis carinii Pneumonia with Analogs of Pentamidine
Authors: TIDWELL R.R. , KILGORE S. G. , OHEMENG KJV. , GERATZ J.D. , HALL JAMES EDWIN
Published: May 2007

Seven analogs of pentamidine were tested for their activity against an immunosuppressed rat model of Pneumocystis carinii pneumonia. Structural alterations of the pentamidine molecule included variations of the alkyl chain linking the two p‐amidino phenoxy moieties and relocation of the amidine groups from the para to the meta position on the phenoxy rings. All analogs of pentamidine were active against P. carinii pneumonia when compared to a saline‐treated control group. One derivative, 1, 4‐di(4′‐amidinophenoxyJbutane, proved to be statistically more active than the parent drug.
Freeze‐Fracture Study of the Bloodstream Form of Trypanosoma brucei gambiense
Authors: YOSHIKAWA HISAO , FURUKI JUNKO , TAKAHASHI YUZO , MORIOKA HIROYUKI , YOSHIDA YUKIO
Published: May 2007

The ultrastructure of Trypanosoma brucei gambiense was investigated by the freeze‐fracture method. Three different regions of the continuous plasma membrane; cell body proper, flagellar pocket, and flagellum were compared in density and distribution of the intramembranous particles (IMP's). The IMP‐density was highest in the flagellar pocket membrane and lowest in flagellum. Intra membranous particles of the cell body membrane were distributed uniformly on both the protoplasmic (P) and exoplasmic (E) faces. On the P face of the flagellar membrane, a single row of IMP‐clusters was seen along the juncture of the flagllum to the cell body. Since the spacing of the IMP‐clusters was almost equal to the spacing of the paired rivet structures observed in thin section, these clusters likely are related to the junction of flagellum and cell body. At the neck of the flagellar pocket, several linear arrays of IMP's were found on the P face of the flagellar membrane, while on the E face rows of depressions were seen. At the flagellar base, the clusters of IMP's were only seen on the P face. On the flagellar pocket membrane, particle‐rich depressions and linear particle arrays were also found on the P face, while on the E face such special particle arrangements were not recognized. These particle‐rich depressions may correspond to the sites of pinocytosis of the bloodstream forms which have been demonstrated in thin sections.
Developmental Stages of Trypanosoma (Megatrypanum) freitasi Rego, Magalhaes & Siqueira, 1957 in the Opossum Didelphis marsupialis (Marsupialia, Didelphidae)
Authors: DEANE MARIA P. , JANSEN ANA MARIA
Published: May 2007

Trypanosoma (Megatrypanum) freitasi, a parasite of marsupials of the genus Didelphis, has been found to undergo in the lumen of the scent (anal) glands of its vertebrate host, a cycle such as usually occurs in the intestinal tract of the insect vectors of trypanosomatids and similar to what has been reported for Trypanosoma (Schizotrypanum) cruzi. The invertebrate host of Trypanosoma freitasi is still unknown. Developmental stages of the trypanosome in its mammalian host, especially the dividing epimastigotes, multinucleate plasmodial forms and rosettes found in the lumen of the scent glands of a naturally infected Didelphis marsupialis are described and illustrated.
Coccidia of Brazilian Mammals: Eimeria corticulata N. Sp. (Apicomplexa: Eimeriidae) from the Anteater Tamandua tetradactyla (Xenarthra: Myrmecophagidae) and Eimeria zygodontomyis N. Sp. from the Cane Mouse Zygodontomys lasiurus (Rodentia: Cricetidae)
Authors: LAINSON RALPH , SHAW JEFFREY J.
Published: May 2007

Feces from a specimen of Tamandua tetradactyla (Linn.) from Portel, Para State, north Brazil, contained two different coccidial oocysts; one identified as Eimeria tamanduae Lainson 1968, and the other as a new species, described here as Eimeria corticulata n. sp. Oocysts of E. corticulata are ellipsoidal, 37.4 × 30.4 (31.2–43.7 × 23.7–35.0) μm, shape index (length/width) 1.2 (1.0–1.5). Oocyst wall 2.5–3.7 μm thick and composed of two layers; an outer thick, brown‐yellow one with radial striations, and a thin inner smooth one: no visible micropyle. Oocyst residuum a large globule of about 10.7 × 10.3 μm, usually accompanied by a number of smaller attached globules. Sporocysts ellipsoidal, 21.0 × 11.0 (20.0–22.5 × 10.0–12.5) μm, with a conspicuous Stieda body: shape index 1.9 (1.6–2.2). Sporocyst residuum a small number of scattered granules: sporozoites 18.7 × 5.0 μm, with a large posterior refractile body. Eimeria zygodontomyis n. sp. is described in feces from Zygodontomys lasiurus (Lund) from the Serra dos Carajas, Para. Oocysts ellipsoidal to cylindrical, 16.5 × 12.0 (13.7–18.7 × 11.2–12.3) μm, shape index 1.4 (1.2–1.5). Wall colorless, smooth, single‐layered and about 0.6 μm thick: no micropyle. No oocyst residuum, but a polar granule of about 1.8 × 1.0 μm is sometimes present. Sporocysts ellipsoidal, 8.4 × 5.5(7.5–8.7 × 5.0–6.2) μm, shape index 1.5 (1.4–1.7), with a thin colorless wall and a delicate Stieda body. Sporozoites enclose a compact residuum of about 2.5 × 3.7 μm.
Specific and Common Epitopes in Mating Pheromones of Euplotes raikovi Revealed by Monoclonal Antibodies
Authors: FIORI PIER LUIGI , MICELI CRISTINA , RAFFIONI SIMONA , VALLESI ADRIANA
Published: May 2007

Polypeptide mating pheromones Er‐1 and Er‐2, purified from the supernatant of Euplotes raikovi cultures of mating type I and mating type II, respectively, were used to immunize mice and obtain monoclonal antibodies. Five hybridoma clones producing antibodies specific to the mating pheromones were selected. They were analyzed for immunospecificity by immunoperoxidase assay, immunoblotting, and for their efficacy in inhibition of mating pheromone activity. Monoclonal antibodies from two hybridoma clones recognized only the mating pheromone used as antigen; those from the other three clones reacted, to comparable extents, with both mating pheromones. On the basis of these results it was assumed that two immunogenic sites exist in Er‐1 and Er‐2, one specific and the other common to both mating pheromones.
Trypanosoma brucei rhodesiense Bioodstream Forms: Surface Ricin‐Binding Glycoproteins are Localized Exclusively in the Flagellar Pocket and the Flagellar Adhesion Zone
Authors: BRICKMAN MARLA J. , BALBER ANDREW E.
Published: May 2007

Specific binding of fluoresceinated succinyl‐concanavalin A, wheat germ agglutinin, and ricin to untreated and trypsinized bloodstream forms of Trypanosoma brucei rhodesiense was quantitated by flow cytofluorimetry, and sites of lectin binding were identified by fluorescence microscopy. All three lectins only bound to the flagellar pocket of untreated parasites. When parasites were trypsinized to remove the variant surface glycoprotein coat, new lectin binding sites were exposed, and specific binding of all three lectins increased significantly. New specific binding sites for succinyl‐concanavalin A and wheat germ agglutinin were present along both the free flagellum and flagellar adhesion zone and were uniformly distributed on the parasite surface. However, ricin did not bind uniformly on the surface and did not stain the free flagellum of trypsinized cells. Ricin only bound to the flagellar adhesion zone of trypsinized cells and of cells that had been treated with formaldehyde prior to staining. Electron microscopy of cells exposed to ricin‐colloidal gold complexes revealed that that ricin binding was restricted to the anterior membrane of the flagellar pocket of untrypsinized cells and to this portion of the flagellar pocket and the cell body membrane in the flagellar adhesion zone of trypsinized cells. Evidence that these membranes constitute a functionally important membrane microdomain is reviewed.
Glucokinase and Fructokinase of Trichomonas vaginalis and Tritrichomonas foetus
Authors: MERTENS EMMANUEL , MÜLLER MIKLØ
Published: May 2007

ABSTRACT. Trichomonas vaginalis and Tritrichomonas foetus contain glucokinase and not a hexokinase of broad hexose specificity. Tritrichomonas foetus also contains a specific fructokinase which could be resolved from glucokinase by anion exchange chromatography. Native T. vaginalis glucokinase had a Mr of 76,000, and SDS‐PAG electrophoresis showed two equally stained bands corresponding to Mr 40,000 and 38,000. Glucose and ATP were by far the best substrates for both trichomonad glucokinases, with Km values as low as 33–35 μM and 75–83 μM, respectively. Substrate saturation curves for these enzymes were all hyperbolic. Tritrichomonas foetus fructokinase required fructose and ATP, with Km values of 200 μM and 81 μM. None of the activities was affected by a number of potential regulatory metabolites, including glucose‐6‐phosphate. The only exception was AMP which in supraphysiological concentrations had an inhibitory effect on T. foetus fructokinase. In conclusion, the absence of regulation at the hexose phosphorylation step described here, as well as the presence of an easily reversible PPi: fructose‐6‐phosphate 1 ‐phosphotransferase described previously (Mertens, E., Van Schaftingen, E. & Müller, M. 1989. Mol. Biochem. Parasitol., 37:183–190), suggest that the rate of the 1st part of glycolysis in trichomonads is controlled only by the intracellular availability of hexoses.
Identification and Characterization of Variants of Crithidia luciliae with Altered Morphological and Surface Properties
Authors: ALLEMAN MARY M. , COHN CLAUDIA S. , GOTTLIEB MICHAEL
Published: May 2007

ABSTRACT. Variants of a cloned laboratory stock of the trypanosomatid parasite Crithidia luciliae have been distinguished from “parental type” organisms. These variants accumulated spontaneously over time as the protozoan was maintained by continuous passage in a chemically defined medium. Cloned lines of these variants have been isolated by plating on nutrient agar and partially characterized on the basis of their growth characteristics in culture, their colony and cellular morphology as well as their surface protein expression. One cloned line consisted of motile, flagellated forms which, unlike “parental type” organisms, did not adhere to the surface of culture flasks. Another cloned line was composed of non‐adherent, nonmotile, amastigote‐like forms which were further distinguished from “parental type” cells by virtue of their constitutive expression, in nutrient‐replete medium, of high levels of a surface membrane associated 3′‐nucleotidase/nuclease (3′‐N'ase) activity. Both the motile, flagellated and amastigote‐like variants, like the “parental type” organisms, exhibited elevated levels of the 3′‐N'ase activity upon exposure to purine starvation conditions. The variants described are of potential importance in elucidating the mechanism of induction of the highly regulated 3′‐N'ase activity as well as for understanding the cytoskeletal systems and the surface properties of these protozoa.