bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Long‐Term in Vitro Cultivation on Leishmania donovani Promastigotes
Authors: Nolan Thomas John , Herman Robert 
Published: May 2007

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

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

ABSTRACTThe enzyme activities of 37 representative strains of Acanthamoeba against 19 substrates have been examined. A total of 13 enzyme complements were identified, which could be arranged in six larger groups. There was good agreement between these groupings and the arrangement of the strains that was suggested by the electrophoresis patterns of their esterases and acid phosphatases. A nomericlature is described which provides an unequivocal numerical label for each enzyme complement.
Studies on the Coccidian Parasites (Apicomplexa: Eimeriidae and Pfeifferinellidae) of Pulmonate Gastropods1
Authors: FRITSCHE THOMAS R. 
Published: May 2007

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

ABSTRACTIn the present work we have found that microcalorimetry might be a useful method to record pinocytosis in Amoeba proteus. Sodium‐induced (67 mM) and potassium‐induced (75 mM) pinocytosis caused an increase in heat output of 130 and 325%, respectively. Heat production during lysozyme‐induced (0.43 mg/ml) pinocytosis increased about 100%.
A Multinucleated Marine Amoeba Which Digests Seaweeds1
Authors: POLNE‐FULLER MIRIAM 
Published: May 2007

ABSTRACTMarine 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

ABSTRACTThis 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

ABSTRACTMorphology 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.
Freeze‐Fracture Study of the Endosymbiont of Blastocrithidia culicis1
Authors: SOARES MAURILIO JOSÉ , DE SOUZA WANDERLEY 
Published: May 2007

ABSTRACTThe 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

ABSTRACTThe 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

ABSTRACTThe 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

ABSTRACTThe 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

ABSTRACTEpulopiscium 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.
Entamoeba histolytica: Diffuse Liver Inflammation in Gerbils (Meriones unguiculatus) with Experimentally Induced Amebic Liver Abscess
Authors: CHADEE K. , MEEROVITCH E. 
Published: May 2007

ABSTRACTThe 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

ABSTRACTOrnithine 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

ABSTRACTThe 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

ABSTRACTSpores 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

ABSTRACTThe 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

ABSTRACT.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.