bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

ABSTRACT.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

ABSTRACT.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

SUMMARYThe 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.
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

ABSTRACTPneumocystis 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

ABSTRACTThe 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

ABSTRACTPneumocystis 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

ABSTRACTThe 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

ABSTRACTThe 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

ABSTRACTSeven 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

ABSTRACTThe 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

ABSTRACTTrypanosoma (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

ABSTRACTFeces 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

ABSTRACTPolypeptide 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

ABSTRACTSpecific 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.
Microsporidian Spore Envelope Keratins Phosphorylate and Disassemble During Spore Activation
Authors: WEIDNER EARL , HALONEN SANDRA K. 
Published: May 2007

ABSTRACTThe microsporidian spore stage of the nerve parasite, Spraguea lophii, consists of outer envelope stabilized in part by keratins, including K4 and K13. The nonepidermal K4 and K13 keratins were found only in the spore envelope and were absent in the internal microsporidian sporoplasm. At the time of spore activation, the keratin‐based outer spore envelope assemblage dissociated and became phosphorylated when the spores were placed in the presence of labeled ATP. Verapamil or lanthanum, agents which block S. lophii spore activation, also blocked spore envelope keratin disassembly and phosphorylation when the spores were incubated in activation medium with labeled ATP. However, after the removal of the verapamil or lanthanum, the spores regained the capacity to activate in discharge medium and the keratin analogues appeared to dissociate and phosphorylate.
Investigating the Comparative Biology of the Heterokonts with Nucleic Acids1
Authors: WEE JAMES L. , HINCHEY JEANETTE M. , NGUYEN KIM X. , KORES PAUL , HURLEY DAVID L. 
Published: May 2007

ABSTRACTDuring the last decade investigations of heterokont protists utilizing molecular methods have challenged established biosystematic concepts. Most investigations emphasized the chloroplast genome or sequences from nuclear‐encoded, ribosomal genes. Refinement of DNA isolation protocols, advent of “universal primers” and the polymerase chain reaction, automated sequencing and increased accessibility of DNA sequence databases have expanded data‐gathering efficiency and increased dataset sizes. Because independent datasets have been easier to obtain, the testing of specific phylogenetic hypotheses has been facilitated, altering relationship concepts, primarily at phylum/class levels, and perceptions of cellular evolution. New approaches have emphasized ecological studies and extended studies to genus/species levels and poorly investigated genomes. This paper reviews studies documenting these impacts and identifies some current limitations. Additionally, new DNA sequence data from our laboratory on nuclear‐encoded rDNA internal transcribed spacers and the chloroplast‐encoded psb A gene suggest that these regions will provide taxonomic resolution for the Synu‐rophyceae, at the class/order level and subspecies level, respectively.
Leishmania mexicana amazonensis: Differential Display Analysis and Cloning of mRNAs from Attenuated and Infective Forms
Authors: HEARD PAMELA L. , LEWIS CLARENCE S. , CHAUDHURI GAUTAM 
Published: May 2007

SUMMARYThe virulence of Leishmania mexicana is determined by the concerted action of several parasite molecules. These cells lose their infectivity to host macrophages after prolonged cultivation in axenic growth media. Both virulent and attenuated variants of the parasite cells were cloned. The differential display reverse transcription‐polymerase chain reaction technique was employed to understand whether this natural attenuation of the parasite cells is accompanied by differential expression of selected genes in those cells. Twelve different dinucleotide‐anchored oligo(dT) antisense primers were used to make cDNAs from poly(A)+ mRNAs isolated from a clonal population of virulent and avirulent cells following a protocol optimized for Leishmania mRNAs. Those cDNAs were subjected to amplifications using each of the three different arbitrary decanucleotide primers and the corresponding anchored oligo(dT) primer. This procedure revealed four virulent‐specific cDNA probes and one avirulent‐specific cDNA probe. Differential expressions of these genes were confirmed by northern hybridization using the cloned cDNA probes. These results indicate that differential expression of genes may be the key in determining the molecular basis of leishmanial virulence.
Ultrastructural Features of Spindle Microtubule Organization During the Neclear Division of Encephalitozoon hellem
Authors: SACCHI LUCIANO , BIGLIARDI ELISA , LANZARINI PAOLO , CORONA SILVIA , GATTI SIMONETTA , SCAGLIA MASSIMO 
Published: May 2007

SUMMARYUltrastructural studies were carried out to describe the nuclear division cycel of a strain of Enephalitozoon hellem isolated from an Italina AIDS patient. The nuclear division occurs during the porliferative vegetative phase and it is characterized by the intranuclear mitosis and by the lack of centrioles. The spindle termini are electron dense spindle plaques (ESPs), resembling to the spindle pole bodies (SPBs) of Sacchoaromycetes. The ESPs are bifacial organella forming microtubules on both nucleoplasmic and cytoplasmic faces. In the outer layer of the spindle plaque are present vesicular elements lined by a double membrance of unknown function. The peculiar morphological feacture of E. hellem ESPs indicate that bothe intranclear spindle and cytoplasmic microtubules are involved in the nuclear division.
Fish Trypanosomes: Their Position in Kinetoplastid Phylogeny and Variability as Determined from 12S rRNA Kinetoplast Sequences
Authors: FIGUEROA FELIPE , MAYER WERNER E. , LOM JIŘÍ , DYKOVÁ IVA , WELLER MATHIAS , PECKOVA HANA , KLEIN JAN 
Published: May 2007

ABSTRACTFish trypanosomes have traditionally been classified according to the host species from which they were isolated, each isolate being regarded as a distinct species. To test the soundness of this practice, the genetic variabilities of the kinetoplast 12S rRNA‐encoding genes of different fish trypanosomes isolates were compared. The DNAs were extracted from trypanosomes cloned from blood samples of 15 donors representing ten different fish species in four orders from waters of three major river systems of Central and Northern Europe. Comparison with other trypanosomatid sequences revealed that the fish trypanosomes form a monophyletic group with Trypanosoma brucei as a sister group. Pairwise comparisons of genetic distances yielded a wide range of continuous variation with no indication of any discontinuities attributable to barriers to gene flow. The genetic distances did not correlate with either the identity of the host species or geography. The host specificity of fish trypanosomes appears to be limited.