bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coccidian Parasites (Apicomplexa: Eimeriidae) of Nerodia spp. (Serpentes: Colubridae), with a Description of a New Species of Eimeria
Authors: MCALLISTER CHRIS T. , UPTON STEVE J. 
Published: May 2007

ABSTRACTEimeria conanli n. sp. (Apicomplexa: Eimeriidae) is described from intestinal contents and feces of Nerodia erythrogaster transversa and N harteri harteri from northcentral Texas. Oocysts of the new species are ellipsoid in shape. 17.9 × 13.0(15–21 × 12–15) μm, with a smooth, thin, single‐layered wall; shape index 1.4 (1.2–1.5). One to several (usually 2) polar granule(s) and an oocyst residuum are present, but a micropyie is absent. Sporocysts are elongate, 12.9 × 5.2 (13–15 × 5–6) ‐m, apparently without a true Stieda body structure. Each sporoeyst contains an ellipsoid residuum, 3.9 × 3.2 (3–6 × 2–4) μm, and elongate sporozoites, 11.4 × 2.5 (10–14 × 2–3) μm in situ, each with a spherical or subspherical anterior refractile body and spherical to ellipsoid posterior refractile body. In addition to the new species, oocysts of 4 previously described eimerians from colubrid snakes were found in these hosts.
Lorica Production in Choanoflagellates–A Model System for Investigating the Mechanics, Controls and Dynamics of Secretion
Authors: LEADBEATER BARRY S. C. 
Published: May 2007

BIOMINERALIZATION is the process by which living organisms assemble structures from naturally occurring inorganic compounds. Mineral deposition is common and widespread amongst Protozoa and in most instances the mineralized structures provide skeletal support and protection for softer organic parts [10]. The 2 most common minerals to be deposited by Protozoa are silica and calcium carbonate. Groups of Protozoa that deposit silica, which we are concerned with here, include the diatoms, chrysophytes, choanoflagellates, Radiolar‐ia, Heliozoa and testate amoebae [10].In the majority of silica‐depositing protista, silica is taken up from the medium in the form of monomelic orthosilicic acid Si(OH)4 (soluble reactive silicate) and deposited as amorphous, polymerised biogenic silica or opal within membrane‐bounded vesicles known as silica deposition vesicles (SDV). Often biogenic silica is characteristically patterned and ornamented and for most protozoan groups the morphology of silicified parts is of prime taxonomic importance.By far the most extensively studied group of silica‐depositing organisms are the diatoms [1, 12, 13]. To date most of our knowledge of silica metabolism in protists has been based on investigations into this group. Diatoms require silica for the production of their frustules. Uptake and deposition of silica occurs within a closely denned portion of the cell cycle, between nuclear division and cell separation. It occupies about ± of the cell cycle and without an adequate supply of silica diatoms are unable to produce new frustule valves with the result that cell division cannot be completed. Diatoms, therefore, have an obligate requirement for silica and without this nutrient they cease to grow [11].In contrast to diatoms a number of other silica‐depositing protistan groups, such as loricate choanoflagellates and certain chrysophytes, have a facultative requirement for silica. In the past decade the ultras true ture, physiology and ecology of loricate choanoflagellates have been extensively studied by a number of different workers [7] and the significance of these studies to our understanding of the mechanisms, controls and dynamics of silica secretion is summarised and discussed here.
Morphometries and Redescription of Trypanoplasma borreli Laveran & Mesnil, 1901 (Mastigophora, Kinetoplastida) from Experimentally Infected Common Carp (Cyprinus carpio L.)
Authors: KRUSE PETER , STEINHAGEN DIETER , KÖRTING WOLFGANG , FRIEDHOFF KARL T. 
Published: May 2007

ABSTRACT.Morphological development of cloned Trypanoplasma borreli was studied during the course of experimental infections in common carp. During the course of infection the cell dimensions of T. borreli showed high variability. At the beginning of parasitemia at day 8 p.i. (post inoculation) small and slender T. borreli predominated: surface area (SA, determined using a polar planimeter) 48.9 ± 13.1 Mm2; shape index (SI, length/width) 7.8 + 2.1 (n = 110). During the exponential growth phase until day 13 p.i. the size further decreased significantly (P < 1%): SA 29.9 ± 9.5 μm: (n = 109). During the transition of parasitemia from exponential growth to the chronic phase the size of T. borreli enlarged significantly (P < 1%) and it became stumpy in shape. Day 15 p.i.: SA 63.2 ± 15.8 μm2; SI 4.2 ± 1.0 (n = 51). During the chronic phase significantly (P < 1%) larger trypanoplasms predominated: day 41 p.i. SA 90.6 ± 22.7 μm2, SI 4.9 ± 1.1 (n = 221). Further samples showed only moderate variability of cell dimensions during this phase of parasitemia. Measurements of dimensions of lrinetoplast and nucleus and length of flagella varied in a similar manner. The position of the kinetoplast remained unchanged, while the nucleus had a more anterior position in the chronic phase. Experimental infections of various cyprinids were successful, perch and rainbow trout were not susceptible to experimental infections with T. borreli. Using these data a redescription of T. borreli is given.
Trypanosomatids, Other Than Phytomonas spp., Isolated and Cultured from Fruit
Authors: CONCHON IVETE , CAMPANER MAHTA , SBRAVAT CLIZETE , CAMARGO E. PLESSMANN 
Published: May 2007

ABSTRACTTrypanosomatids were isolated from edible fruit. One of the isolates (from tangerine) presented a set of enzymes for the metabolism of arginine‐ornithine similar to that of Leptomonas spp., and failed to be recognized by monoclonal antibodies specific for Phytomonas spp. The possibility that trypanosomatids other than Phytomonas spp. could infect fruit was further examined by inoculating tomatoes with species of Crithidia, Leptomonas and Herpetomonas. Some of these flagellates multiplied in tomatoes. Besides, house flies became infected with Crithidia sp. when fed on tomatoes experimentally inoculated with this flagellate. Therefore, isolation of a trypanosomatid from a plant should not constitute an absolute criterion for placing it in the genus Phytomonas.
The Site Specificity of Two Species of Gregarina in Tenebrio molitor Larvae
Authors: RUHNKE T. R. , JANOVY J. 
Published: May 2007

ABSTRACTThe site specificity of the apicomplexans Gregarina cuneata and Gregarina sleini, in larval Tenebrio molitor was investigated. Gregarina cuneata was found to inhabit the anteriormost region of the larval midgut, while G. steini was restricted to the posterior portion of the intestine. The site specificity of the pair was conserved in single and concurrent infections. Interspecific interactions do not seem to be presently responsible for the resource partitioning by the 2 gregarine species. Key words. Gregarina, site specificity, Tenebrio molitor.
Characterization and Cloning of Pneumocystis carinii Nucleic Acid
Authors: WORLEY MARK A. , IVEY MICHAEL H. , GRAVES DON C. 
Published: May 2007

ABSTRACT.Large numbers of Pneumocystis carinii (2 × 1010 nuclei) were isolated and separated from the lungs of immunosuppressed rats by an enzymatic (collagenase, hyaluronidase and DNase) digestion procedure. The nucleic acid isolated from this P. carinnii‐enriched preparation was characterized by melting point analysis and RNA‐sizing gels. The GC content of P. carinii DNA was approximately 33% while the rat DNA was 41.4%. In addition, RNA isolated from the P. carinii‐enriched preparation showed unique ribosomal RNA bands of 3.4 kb and 1.8 kb as compared with uninfected rat lung ribosomal RNA which banded at 4.8 and 1.9 kb. Following isolation and fragmentation by sonication, the P. carinii DNA fragments were inserted into the vector, λ gt‐11. The resultant library contained 1.1 × 105 phage, of which 40–45% hybridized to P. carinii DNA but not to rat DNA.
Yeast Glucan in the Cyst Wall of Pneumocystis carinii
Authors: MATSUMOTO YOSHITSUGU , MATSUDA SHINJI , TEGOSHI TATSUYA 
Published: May 2007

ABSTRACTUluastraclurally, the cyst wall of Pneumocystis carinii consists of an electron‐dense outer layer, an electron‐lucent middle layer, and an innermost plasmalemma. This is similar in appearance to the cell wall of some yeasts, e.g. Saccharomyces cerevisiae, which consists of an outer dense layer of mannan, a middle lucent layer of β‐1,3‐glucan (yeast glucan) and an innermost plasmalemma. The cyst wall of P. carinii, as well as the cell wall of S. cerevisiae, can be labeled by a variety of methods which stain polysaccharides, such as Gomori's methenamine silver (GMS) and by Aniline blue, a dye which selectively stains β‐l,3‐glucan. The treatment of P. carinii cysts with Zymolyase, which the key enzyme is β1‐l,3‐glucan laminari‐pentaohydrolase, results in lysis of the outer 2 layers of the cyst wall and the loss of positive staining by both GMS and Aniline blue. The lysis of elements of the cyst wall of P. carinii is achieved under the same conditions and concentration at which Zymolyase lyses the outer 2 layers of the cell wall of viable cells of S. cerevisiae. These observations indicate that a major component of the cyst wall of P. carinii is β‐l,3‐glucan.
A Fifteen‐Year Perspective on the In Vitro Culture of Pneumocystis carinii
Authors: PIFER LINDA L. 
Published: May 2007

ABSTRACTThe in vitro cultivation of Pneumocystis carinii in chick lung cell culture made it possible to observe the organism proceeding through its life cycle. It provided the foundation for extensive serocpidcmiologic studies, for in vitro drug screening, and for essential biological, metabolic, and morphologic research. In vitro culture made possible the discovery of P. carinii antigenemia, its biochemical nature, and its relevance to subclinical and clinical infection. Its utility in the presumptive diagnosis of P. carinii pneumonia and in monitoring responses to drug therapy illustrate the value and clinical application of basic research.
Dynamics of Pneumocystis carinii‐Specific Immune Complexes in AIDS Patients with P. carinii Pneumonia
Authors: PIFER LINDA L. 
Published: May 2007

ABSTRACTPneumocystis carinii‐specific immune complexes were detected by immunoblot and enzyme‐linked immunosorbent assay (EUSA) in 53% of sera from Acquired Immunodeficiency Syndrome (AIDS) patients with P. carinii pneumonia (PCP). Resolution of glycoprotein antigenemia (50–55 kd = dominant species) appears to correlate with successful PCP drug therapy and recovery. An epitope map has been constructed from im‐munoblots of P. carinii hydrolysates and from human and murine serum containing P. carinii antigens.
S‐Antigen Localization in the Erythrocytic Stages of Plasmodium falciparum
Authors: CULVENOR JANETTA G. , CREWTHER PAULINE E. 
Published: May 2007

ABSTRACTLocalization of the S‐antigen of Plasmodium falciparum isolate FCQ27/PNG, from Papua New Guinea, was studied by post‐embedding immunoelectron microscopy using affinity‐purified rabbit antibodies raised against the repeat region of the antigen. Labelling was found in the parasitophorous vacuole (PV) space of early to late schizonts and in PV‐related vesicles within the erythrocyte cytoplasm of schizont‐infected cells. Other subcellular structures within the erythrocyte cytoplasm were not labelled. After breakdown of the PV membrane, label was observed around the merozoites, consistent with mixing of the PV contents and erythrocyte cytoplasm. The antigen was not found in uninfected cells, ring stages, trophozoites or associated with free merozoites. Antibodies to FCQ27/PNG S‐antigen did not react with other isolates tested, whereas rabbit antibodies to the Palo Alto/Wellcome S‐antigen repeat region reacted with isolates FCR3 and ItG2F6 but not with FCQ27/PNG.
Size Effects on the Uptake of Particles by Populations of Tetrahymena pyriformis Cells
Authors: LAVIN DANIEL P. , HATZIS CHRISTOS , SRIENC FRIEDRICH , FREDRICKSON A. G. 
Published: May 2007

ABSTRACTFlow cytometry has been used to make direct measurements of rates of uptake of latex microspheres from dilute, monodisperse suspensions by Tetrahymena pyriformis. Measurements were made for five different sizes of microspheres, ranging from 1.09 to 6.17 μm diameter. Fractions of cells in the population that did not ingest the microspheres offered were also determined. In addition, the size distributions, as indicated by the forward angle light scattering intensity which is measured by the instrument, were determined for the whole population and for the subpopulations of cells that did and did not ingest the particles, for each particle size used. It was found that the fraction of cells that did not ingest the particles was small and independent of particle size when this was less than about 2.7 μm, but increased with particle size when particle size was increased above this value. The so‐called maximum clearance rate, which can be calculated from the data, was found to increase monotonically with particle size if it were based only on those cells which actually ingested the particles offered. However, a plot of maximum clearance rate vs. particle size exhibited a maximum if the clearance rate were based on all cells present in the population.
A Light and Electron Microscopic Study of Trypanosoma fallisi N. Sp. in Toads (Bufo americanus) from Algonquin Park, Ontario
Authors: MARTIN DONALD S. , DESSER SHERWIN S. 
Published: May 2007

ABSTRACTTrypanosoma fallisi n. sp. is described from Bufo americanus in Ontario. The parasite was observed in 65 of 94 toads examined. The trypanosomes were pleomorphic with respect to the age of infections, being longer and broader in early infections (during spring and summer) and shorter and more slender during late summer and autumn. They ranged in size from 38–76 μm in body length and 3–8 μm in width, with a free flagellum 6–30 μm long. Epizootiological and experimental evidence suggests that this trypanosome is transmitted to the toads by the leech, Batracobdella picta. Trypanosoma fallisi is morphologically similar to T. bufophlebotomi described in Bufo boreas from California, but geographic isolation, host and vector differences as well as slight morphological differences indicate that speciation has occurred. Similar trypanosomes from Bufo americanus (which were identified as T. bufophlebotomi) in Michigan, are probably T. fallisi. This species shares many ultrastructual features with trypanosomes of other lower vertebrates and also of mammals.
Ultrastructural Studies on the Trypanosomatid Phytomonas serpens in the Salivary Glands of a Phytophagous Hemipteran
Authors: FREYMULLER EDNA , MILDER REGINA , JANKEVICIUS J. V. , JANKEVICIUS SHIDUCA I. , CAMARGO E. PLESSMANN 
Published: May 2007

ABSTRACTElectron microscopy of salivary glands of the phytophagous hemipteran Phihia picta infected with Phytomonas serpens revealed the presence of flagellates in the gland periphery beneath the gland envelope, in the gland central lumen, between gland cells in the intercellular space and inside the gland cells. In the latter case, flagellates were found in the cytoplasm whether or not it was surrounded by a vacuolar membrane. Flagellates were always of the promastigote type, sometimes displaying a large twisted body. Morphological peculiarities of flagellates in different gland locations are recorded.
Genome Structure and Evolution of Naegleria and its Relatives
Authors: CLARK C. GRAHAM 
Published: May 2007

ABSTRACTIn the 4 yr since the molecular biology of DNA in Naegleria was last reviewed several major advances have been made, and these are reviewed here: isolation and characterization of mitochondrial and ribosomal DNAs; enumeration of chromosomal DNAs by pulsed field gel electrophoresis; sequence analysis of differentially expressed genes; phylogenetic placement of the genus Naegleria among the eukarayotes and Naegleria species within the genus.
Epidemiology of Free‐Living Ameba Infections1
Authors: VISVESVARA GOVINDA S. , STEHR‐GREEN JEANETTE K. 
Published: May 2007

ABSTRACTSmall free‐living amebas belonging to the genera Acanthamoeba and Naegleria occur world‐wide. They have been isolated from a variety of habitats including fresh water, thermal discharges of power plants, soil, sewage and also from the nose and throats of patients with respiratory illness as well as healthy persons. Although the true incidence of human infections with these amebas is not known, it is believed that as many as 200 cases of central nervous system infections due to these amebas have occurred world‐wide. A majority (144) of these cases have been due to Naegleria fowleri which causes an acute, fulminating disease, primary amebic meningoencephalitis. The remaining 56 cases have been reported as due either to Acanthamoeba or some other free‐living ameba which causes a subacute and/or chronic infection called granulomatous amebic encephalitis (GAE). Acanthamoeba, in addition to causing GAE, also causes nonfatal, but nevertheless painful, vision‐threatening infections of the human cornea, Acanthamoeba keratitis. Infections due to Acanthamoeba have also been reported in a variety of animals. These observations, together with the fact that Acanthamoeba spp., Naegleria fowleri, and Hartmannella sp. can harbor pathogenic microorganisms such as Legionella and or mycobacteria indicate the public health importance of these amebas.
Effect of Gossypol on Trypomastigotes and Amastigotes of Trypanosoma cruzi
Authors: ROVAI LEONOR E. , AOKI AGUSTIN , BURGOS NELIA M. GEREZ DE , BLANCO ANTONCO 
Published: May 2007

ABSTRACTBloodstream Trypanosoma cruzi trypomastigotes isolated from infected mice undergo reduction of motility and structural damages after 5 to 45 min exposure to gossypol at concentrations ranging from 5 to 50 μM. When 1% serum albumin is added to the incubation medium, no alterations of parasites are observed, even with 100 μM gossypol. Intracellular T. cruzi amastigotes in infected Vero cell cultures exposed to 5 μM gossypol for 2 h do not show changes. Incubation with 5 μM gossypol for 48 h produces complete disruption of host cells; however, the amastigotes they contain show only mineor alterations. The observations indicate that, in protein‐rich media, gossypol is complexed into associations which have no activity on the different forms of the T. cruzi biological cycle.
Morphological Drift Accompanying Nascent Population Differentiation in the Ciliate Euplotes vannus
Authors: GATES MICHAEL A. 
Published: May 2007

ABSTRACTA rare phenomenon can occur in ciliated protists of the genus Euplotes, which can undergo genetic recombination by the normal outbreeding process of conjugation following mild starvation. Occasionally, the dominant mutation for the autogamy trait arises. Individuals possessing the trait show obligate self‐fertilization upon mild starvation. This yields, after normal asexual division, a population of individuals that are reproductively isolated from the parental outbreeding strain. A morphometric analysis of sympatric autogamous and non‐autogamous populations of Euplotes vannus from Somalia demonstrates that there has been morphological drift in gross body proportions in the autogamous populations. However, the positional patterns of the locomotory organelles on the ventral surface remain unchanged. The changes in body proportions in the autogamous populations are relevant to the mechanics of the conjugation process, which involves fusion of the oral regions of paired cells belonging to complementary mating types.
Sphaerospora ictaluri N. Sp. (Myxosporea: Sphaerosphoridae) Observed in the Kidney of Channel Catfish, Ictalurus punctatus Rafinesque
Authors: HEDRICK R. P. , McDOWELL T. , GROFF J. M. 
Published: May 2007

ABSTRACTSphaerospores were found in the kidneys of alevin channel catfish (Ictalurus punctatus) from a farm in Central California. MulticelluUr developmental stages, similar to C‐blood protozoans described for Sphaerospora spp. from cyprinid fishes, were observed in circulating blood and numerous tissues. Upon a 2nd examination of the same population offish 10 days later, sporogonic stages were seen developing into mature Sphaerospores in the lumina of the kidney tubules. Sporogeoesis was asynchronous with simple unicellular stages adjacent to more complex forms with developing polar capsules and valves. Only one elliptical spore (5.6 μm in width, 6.5 μm in thickness by 5.8 μm in length) developed within the surrounding pscudoplasmodium. Thin valves surrounded two sporoplasm cells and two subspherical polar capsules (1.7 × 1.9 μm) which contained a polar filament with four to five turns. The blood stages of the Sphaerospora sp. described here are similar to the trophozoites seen in channel catfish with proliferativc gill disease (PGD). Early stages of PGD also observed in the same population of channel catfish containing developmental and sporogonic stages of this newly recognized Sphaerospora sp. may suggest a causal relationship between this new myxosporean and the gill disease.
Intracellular Development of Enterocytozoon, A Unique Microsporidian Found in the Intestine of AIDS Patients
Authors: CALI ANN , OWEN ROBERT L. 
Published: May 2007

ABSTRACTEnterocytozoon was 1st described in 1985, in an AIDS patient with intestinal malabsorption and diarrhea. Since then, additional cases of infection with this organism have been observed, but only in individuals with AIDS and malabsorption. Intestinal tissue biopsies were obtained from a 45‐year‐old man prior to AIDS diagnosis, again nine months later and then at autopsy two months later. When the biopsies were examined electron microscopically, both sets contained the microsporidian parasite. However, the 2nd intestinal biopsy, when wasting was much more severe, contained infection in almost every small intestinal enterocyte examined. The parasite was actively developing, allowing us to detail its life cycle. The parasite is apansporoblastic, polysporous and has characteristics not previously reported in the Microsporida: (1) an electron lucent inclusion not usually seen in Microsporida is prominent and always present; (2) extremely elongated sausage‐shaped nuclei occur in the proliferative phase of parasite development; (3) the polar tube development uniquely involves the production of electron dense discs, yet results in the formation of a typical spore; and (4) polar tube development occurs prior to the final division of the multi‐nucleate sporont. On the basis of these characteristics, we are placing this genus in a new family, Enterocytozoonidae, n. fam.
A Rhodopsin‐like Molecule on the Plasma Membrane of Fabrea salina
Authors: PODESTA ADRIANO , MARANGONI ROBERTO , VILLANI CHIARA , COLOMBETTI GIULIANO 
Published: May 2007

ABSTRACTImmunofluorescence was used to reveal the presence of a rhodopsin‐like molecule on the plasma membrane of the photoresponsive ciliate Fabrea salina. The ciliate, fixed on a glass support, showed a spontaneous red‐orange fluorescence. Cells incubated with a fluoresceinated, anti‐bovine opsin, sheep polyclonal antiserum showed instead a green fluorescence typical of fluorochrome excited at 436 nm, whereas cells incubated with a fluoresceinated, nonimmune sheep serum kept their original red fluorescence. Excess bovine opsin did not inhibit the antibody reaction, but detergent‐coated purified bovine opsin was proven able to bind to the cell membrane. Since rhodopsin belongs to a gene‐related protein family, which includes adrenergic or cholinergic receptors, the cell response to acute exposure to muscarinic and adrenergic agonist and antagonist drugs was investigated. Acetylcholine, atropine, hexamethonium, noradrenaline, or phenoxybenzamine in the culture medium (10‐4 M) did not influence motion behaviour nor phototaxis of Fabrea salina. These findings raise the possibility that a rhodopsin‐like molecule is present on the surface of Fabrea salina. Nevertheless, they do not prove that this surface antigen is a rhodopsin, or that this molecule is responsible for photoresponsiveness in this organism.