bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cortical Ultrastructure of the Scuticociliates Dexiotricha media and Dexiotricha colpidiopsis (Hymenostomata)*†
Authors: PECK ROBERT K. 
Published: May 2007

SYNOPSIS. Cortical ultrastructure of the scuticociliates Dexiotricha media and Dexiotricha colpidiopsis was investigated. The following elements of the somatic cortex were studied: the cell membrane, alveolar membranes and the epiplasm, kinetodesmal fibers, postciliary and transverse microtubular ribbons, and transverse fibers associated with single and paired kinetosomes; mitochondria and single microtubules located in interkinetal ridges; mature and early extrusion stages of mucocysts: the expulsion vacuole pore and tube, the nephridioplasm and the cytoproct. In the buccal cortex, the paroral kinety‐ribbed wall complex, the 3 polykineties, and the cytostome‐cytopharynx were investigated.Comparative survey of ciliate ultrastructure indicates 2 principal orientation patterns for kinetodesmal and postciliary fibers, recognition of which leads to reevaluation of the theory of paroral kinety formation and the ideas of homology based on this theory. Ultrastructurally, the scuticociliates are not distinct from tetrahymenines and peniculines; the 3 groups appear to be 1 assemblage.
Fine Structure of the Cell Surface and Golgi Apparatus of Ochromonas*
Authors: KAHAN DAVID , OREN RACHEL , AARONSON S. , BEHRENS U. 
Published: May 2007

SYNOPSIS. Ochromonas danica has an unusually flexible cell surface capable of producing projections of varying sizes and shapes: large projections, 340–360 nm long, and small projections, 50–110 nm long. These projections have been demonstrated by transmission and scanning electron microscopy; some of them may break off into the medium and be the source of extracellular membranes and vesicles reported in the cell‐free O. danica growth medium. Ruthenium red stained the acid mucopolysaccharide layer just outside the cell surface as well as small blebs at the cell surface.The Golgi complex of O. danica, Ochromonas malhamensis, Ochromonas sociabilis and Ochromonas sp. produced small coated vesicles which may move toward and fuse with the plasma membrane. The role of the several vesicles is unknown but possible functions are discussed.
The Occurrence of Amphizoic Amebae in Domestic Animals
Authors: KADLEC V. 
Published: May 2007

SYNOPSIS Random examination of domestic animals revealed the frequent presence of free‐living amebae in their bodies. In diseased or dead cows, dogs, pigs, rabbits, pigeons, and turkeys 15 strains of amebae were found, belonging to the genera Acanthamoeba (A. polyphaga), Hartmannella (H. vermiformis), and Vahlkampfia (V. avara, V. enterica, V. inornata)., They were usually accompanied by other infectious agents in different parts of the host bodies. Pathogenicity of 3 isolates could not be demonstrated by inoculation of laboratory animals.Some features of the isolates differed from those previously known for members of these genera. These strains may be considered amphizoic amebae according to Page (1974).
Regulation of Macronuclear DNA Content in Paramecium tetraurelia*†
Authors: BERGER JAMES D. 
Published: May 2007

Synopsis.The amitotic division of the macronucleus of Paramecium tetraurelia produces daughter macronuclei which frequently differ in DNA content. In wild‐type cells these differences are small, but can be increased substantially by the action of mutant genes. The variance in macronuclear DNA content would increase continuously if there were no mechanism to regulate it. Paramecium has a very effective regulatory mechanism—all cells synthesize similar amounts of macronuclear DNA, regardless of the number of macronuclei or their prereplication DNA content. DNA synthesis is controlled at the level of macronuclear subunits, and the postreplication macronucleus consists of a mosaic of subunits that have undergone different numbers of replication events during the previous cell cycle. It is evident from experimental results that the amount of DNA synthesized can be influenced by the total size or mass of the cell. Experimental modification of the initial DNA content leads to no change in the amount of DNA synthesized, or in the subsequent protein content of the cells, but modification of cell size causes corresponding changes in the amount of DNA synthesized and in the size of the macronucleus. The implications of these observations for cell growth and the cell cycle are discussed.
Spores of a New Microsporidan Species Parasitizing Molluscan Neurons
Authors: KRAUHS J. M. , LONG J. L. , BAUR P. S. 
Published: May 2007

Synopsis.A new species of Microsporida was observed in neurons of the marine mollusc Aplysia californica and the ultrastructure of its spores was investigated. The spores were ˜ 1.3 m̈m long and had a thick 3‐layered coat. An anchoring disc and polar aperture were present. The polaroplast occupied most of the anterior half of the spore. The vesicular portion included lengths of loosely packed lamellar structures as well as the usual vesicular profiles embedded in fibrillar material; it was entirely surrounded by tightly packed, electron‐dense lamellae. The polar tube had 5 or 6 coils. In this stage of the life cycle (mature spores), the parasites did not appear to be disturbing the host cells. The organism was named Microsporidium aplysiae sp. n.
Structure of Trichomonads as Revealed by Scanning Electron Microscopy*†
Authors: WARTON̄A ANDRZEJ , HONIGBERG B. M. 
Published: May 2007

SYNOPSIS.A scanning electron microscope (SEM) study of Hypotrichomonas acosta (Moskowitz), Trichomonas vaginalis Donné. Pentatrichomonas hominis (Davaine), and Tritrichomonas foetus (Riedmüller) provided new information about the structure of the periflagellar canal: emergence of the flagella from the cell body; structure of the undulating membrane; and position, shape, and size of the pelta. Of special interest were the spatial relationships of the attached part of the recurrent flagellum and the accessory filament in Hypotrichomonas and in the members of Trichomonadinae, i.e. Trichomonas and Pentatrichomonas.
Ultrastructural Damage to the Malaria Parasite in the Sickled Cell
Authors: FRIEDMAN MILTON J. 
Published: May 2007

SYNOPSISThe process by which malaria parasites are killed in sickled erythrocytes was studied by electron microscopy. In vitro cultures of Plasmodium falciparum in sickle cell hemoglobin (HbS) homozygous (SS) and heterozygous (SA) red cells were deoxygenated for up to 6 h and fixed under anaerobic conditions. Parasites in SS cells appeared to be disrupted by intrusions of needle‐like deoxyHbS aggregates; disintegration of cytoplasm and membranes followed. In SA red cells, the parasites were generally not disrupted. Instead, extensive vacuolization occurred, a sign of metabolic inhibition. The resistance of HbS gene carriers to malaria results partly from these causes of intracellular parasite death.
RNA Synthesis in Isolated Nuclei of the Dinoflagellate Crypthecodinium cohnii
Authors: RIZZO PETER J. 
Published: May 2007

SYNOPSISAtypical eukaryotic RNA polymerase activity was demonstrated in nuclei of Crypthecodinium cohnii, a eukaryote devoid of histones. Nuclei were isolated from growing cultures of this dinoflagellate and assayed for endogenous RNA polymerase (EC 2.7.7.6) activity. There was a biphasic response to Mg2+ with optima at ˜ 0.01 and 0.02 M MgCl2, but in contrast to other eukaryotic RNA polymerases, this enzyme activity was inhibited by low MnCl2 concentrations. In the presence of 0.01 M MgCl2 the optimum (NH4)2SO4 concentration was 0.025 M, a concentration at which the nuclei were lysed. Incorporation of [3H]UMP into RNA was inhibited by actinomycin D and dependent on the presence of undegraded DNA, and the reaction product was sensitive to ribonuclease and KOH digestion. Omission of one or more ribonucleoside triphosphates greatly reduced the incorporation. Only a slight enhancement of RNA polymerase activity resulted from the addition of various amounts of native and denatured calf thymus DNA. Spermine caused a marked inhibition while spermidine had little effect on RNA synthesis in the nuclei. Under the optimum conditions described in the present paper the nuclei incorporated ˜ 3 pmoles of [3H]UMP/muml; DNA at 25 C for 15 min, and ˜ 80% of this activity was inhibited by the eukaryotic RNA polymerase II inhibitor, α‐amanitin (20 m̈/ml). A unique situation therefore exists in C. cohnii nuclei, in which absence of histones (a prokaryotic trait) is combined with α‐amanitin‐sensitive RNA polymerase activity (a eukaryotic trait).
Transport of L‐Proline and its Regulation in Leishmania tropica Promastigotes*
Authors: LAW SUSAN S. , MUKKADA ANTONY J. 
Published: May 2007

SYNOPSISLeishmania tropica promastigotes transport L‐proline through an active uptake system that has saturation kinetics, temperature dependence, a requirement for metabolic energy and transport against a concentration gradient. In experiments lasting 10 min, less than 10% of the proline transported is incorporated into macromolecules. The remainder is largely unaltered proline with an intracellular concentration nearly 60 times that in the reaction mixture. The uptake system has a relatively broad specificity; it is competitively inhibited by D‐proline as well as by alanine, methionine, valine, azetidine‐2–carboxylate, thioproline, 3,4–dehydroproline, hydroxyproline and α‐aminoisobutyric acid. Pre‐established intracellular proline pools exchange with external proline as well as compounds that compete with it for uptake. Evidence is presented that feedback inhibition and transinhibition may regulate proline uptake in this organism.
Characterizations of Phospholipids from Paramecium tetraurelia Cells and Cilia*,†
Authors: RHOADS DENNIS E. , KANESHIRO EDNA S. 
Published: May 2007

SYNOPSISPhospholipids from Paramecium tetraurelia strains 51s and d,95 cultures and isolated cilia were characterized. The following classes of phospholipids were identified in whole cell lipids: the 1‐alkyl‐2–acylglyceryl and the 1,2–diacylglyceryl forms of phosphonylethanolamine, phosphorylethanolamine. and phosphorylcholine; cardiolipin: ceramide aminoethylphosphonate and 5 other sphingolipids: phosphatidylserine; phosphatidylinositol; and lyso derivatives of the major glycerophospholipids. Cilia lipids were rich in ether lipids, phosphonolipids. and sphingolipids. Net lipid biosynthesis did not occur, as determined by the weight of lipids extracted from culture medium compared with the weight of lipids extracted from culture medium and ciliates after 7 days of growth. Total lipids/cell decreased with culture age. changes in the neutral lipid fraction accounting for the major decrease. Phospholipid class distributions changed with culture age—the glyceryl phosphorylethanolamine and choline content of cells decreased, while the glyceryl ohosphonylethanolamine content remained relatively constant: hence, the ratio of phosphonolipids to total phospholipids increased. All fatty acids observed in total lipids from cells and cilia were also present in the glycerophospholipids. Total lipids from cilia contained a greater percent of polyunsaturated fatty acid than those of whole cells. Whole cells and cilia glyceryl phosphonolipids contained up to 93% eicosatetraenoic plus eicosapentaenoic fatty acids. The enrichment of phosphonolipids in cilia accounted for most of the polyunsaturated fatty acid enrichment observed in cilia total lipids. The fatty acid composition of all major whole cell glycerophospholipid classes changed dramatically with culture age, while only small changes occurred in cilia glycerophospholipid fatty acids.
Etude Ultrastructurale de la Sporulation de Paramarteilia orchestiae gen. n., sp. n., Parasite de l'Amphipode Orchestia gammarellus (Pallas)
Authors: GINSBURGER‐VOGEL THOMAS , DESPORTES ISABELLE 
Published: May 2007

RESUME. L'individualisation de 2 spores bicellulaires à partir d'un měme pansporoblaste caractérise la sporulation du parasite de l'Amphipode Orchestia gammarellus (Pallas) précédemment décrit sous le nom de Marteilia sp. Cette sporulation le distingue des espèces du měme genre parasite d'Huǐtres qui sont toutes caractérisées par la production de spores tricellulaires. Les conditions semblables dans lesquelles les pansporoblastes paraissent se differencier à partir d'une cellule souche dans laquelle ils poursuivent leur évolution vers la sporogenèse ainsi que divers caractères cytologiques communs, nous incitent à maintenir tous ces parasites dans une měme famille mais à placer celui de l'Amphipode dans un genre différent. Nous proposons de le nommer Paramarteilia orchestiae gen. n., sp. n.Ces parasites ne peuvent ětre maintenus dans les Protozoaires en raison de leur évolution vers la pluricellularité et de l'individualisation de ces éléments somatiques que représentent la cellule souche primaire, les pansporoblastes et cellules sporales (à l'exception des sporoplasmes). Il semble logique de les inclure dans l'embranchement des Myxozoaires créé par Grassé pour les Myxosporidies et Actinomyxidies qui différencient également des spores pluricellulaires et des éléments somatiques. Les centrioles à 9 singlets de P. orchestiae ainsi que les cellules primaires uninucléées, quel que soit le nombre de pansporoblastes qu'elles contiennent, peuvent ětre considérés comme des caractères résiduels d'Unicellulaires.
Growth and Differentiation of Trypanosoma cruzi Cultivated with a Triatoma infestans Embryo Cell Line*
Authors: LANAR DAVID E. 
Published: May 2007

SYNOPSIS. Trypanosoma cruzi strain Peru was cultivated in the presence of an established cell line of Triatoma infestans embryo cells (TI‐32). Bloodstream trypomastigotes differentiated into amastigote‐like cells (first differentiation phase) which multiplied to form large clusters of cells. Because of their clustering nature, a new term, “staphylomastigotes,” has been proposed for this stage. After 10 days of cultivation, 90% of the staphylomastigotes underwent differentiation (2nd differentiation phase) to trypomastigotes (˜98%) or epimastigotes (˜2%). Bloodstream trypomastigotes cultivated without TI‐32 cells underwent the first, but not the 2nd differentiation phase, although occasional epimastigotes were seen (< 1%). The evidence presented suggests that TI‐32 cells produce a labile factor(s) important not only for initiation of the 2nd differentiation phase but also for maintaining the parasites in the trypomastigote stage. The pH of the culture medium was not the initiating factor for the 2nd differentiation phase.Infectivity studies indicated that staphylomastigotes were as infective as bloodstream trypomastigotes, but that metacyclic trypomastigotes isolated from culture after the 2nd differentiation phase were slightly more infective than bloodstream forms.Electromicrographs of styphylomastigotes do not provide any evidence of exchange of genetic material between cells.
Isozymic Characterization of Three Mating Groups of the Tetrahymena pyriformis complex*
Authors: NANNEY D. L. , COOPER L. E. , SIMON E. M. , WHITT G. S. 
Published: May 2007

SYNOPSIS. Strains of 3 unnamed mating groups of the Tetrahymena pyriformis complex have been subjected to starch gel electrophoresis followed by staining the gels for the enzymes isocitrate dehydrogenase (NADP), tyrosine aminotransferase, and tetrazolium oxidase (superoxide dismutase). With respect to the electrophoretic mobilities of these enzyme systems, the mating groups referred to here as 5, 13 and 14 are very similar to Tetrahymena americanis (syngen 2), the most common North American species of the complex.Cultures in our collection labeled Tetrahymena cosmopolitans (formerly syngen 4) are either amicronucleate, with unique isozyme patterns, or micronucleate cells which mate with and have isozyme patterns similar to Tetrahymena canadensis (syngen 7). Immature progeny have been derived from crosses between the latter strains and T. canadensis recently collected in Colorado. The amicronucleate strains are now placed in the Tetrahymena sp. category, and we conclude that strains identifiable as T. cosmopolitanis are no longer available.The reliability of isozymes as characters in ciliate taxonomy was evaluated by comparing the present results for 3 enzymes in 15 groups of strains (syngens and phenosets) that had been compared in an earlier study. These enzyme systems gave correlation coefficients (r) of 0.75 or higher in the separate studies, and can be considered useful diagnostic traits. Other enzymes that were present at threshold levels of detectability or varied highly in concentration from species to species are too unreliable to be of diagnostic value. Some of the strains in the complex are so evolutionarily divergent at the molecular level that we have difficulty finding growth and electrophoretic conditions under which orthologous enzyme activities can be detected simultaneously for all the strains being compared.
Rhodomonas lacustris(Pascher & Ruttner) Javornicky (Cryptomonadida): Ultrastructure of the Vegetative Cell
Authors: KLAVENESS DAG 
Published: May 2007

ABSTRACTThe ultrastructure ofRhodomonas lacustriswas examined using scanning and transmission electron microscopy, and the pigments were scanned in vivo by the opal plate technique. The periplast is composed of hexagonal plates, with trichocysts at the corners. This cryptomonad lacks a gullet but has a deep ventral furrow, in which more than 20 large ejectosomes are located. The chloroplast has mainly three thylakoids per lamella, and it is structurally reminiscent of that of certain haptophycean flagellates. The pigments appear to be as usual within the photosynthetic cryptomonads, with phycoerythrin type PE I (phycocyanin was not detected). Other cellular inclusions (e.g., lysosome‐like vesicles and the contractile vacuolar complex) are also discussed.
The Cultivation of Blastocrithidia triatomae Cerisola et al., 19711
Authors: PENG PHILLY LIN‐MOO , WALLACE F. G. 
Published: May 2007

ABSTRACTBlastocrithidia triatomae, a species very resistant to cultivation in conventional media, was successfully grown in association with cultured lepidopteran cells. The cultured flagellates were identical to those in the insect host, including the presence of characteristic cysts on the flagellum. Growth rate was better for cultures in the Heliothis zea medium than in IPL‐45 medium or modified McConnell's medium.
Ultrastructural Differences Between Species of Trypanosomatids With and Without Endosymbionts1
Authors: FREYMULLER EDNA , CAMARGO E. PLESSMANN 
Published: May 2007

ABSTRACTSpecies of trypanosomatids without endosymbionts (Leptomonas seymouri, L. collosoma, L. samueli, Crithidia fasciculata, C. luciliae, C. acanthocephali, Herpetomonas megaseliae, H. mariadeanei, H. samuelpessoai, H. muscarum muscarum, Trypanosoma cruzi) and species of trypanosomatids with endosymbionts (Crithidia deanei, C. oncopelti, Blastocrithidia culicis) were comparatively studied by means of electron microscopy. Artificially aposymbiotic strains derived from species with symbiont were also included in the survey. Species with symbiont were found to differ in some ultrastructural aspects from the group of species without symbiont. Paraxial rods of flagella or intraflagellar structure were found exclusively in species without symbiont. Peripheral branching of mitochondria, accompanied by absence of subpellicular microtubules in sites where the mitochondrial branches are appressed to the cell membrane, were found exclusively in species with symbiont. Networks of kinetoplast DNA fibrils were found to be larger and looser in species with symbiont. Symbiont‐free strains of species with symbiont retained the same morphological characteristics of their parental species.
Structure and Elemental Composition of the Cyst Wall of Echinosphaerium nucleofilum Barrett (Heliozoea, Actinophryida)1
Authors: PATTERSON DAVID J. , THOMPSON DUDLEY W. 
Published: May 2007

ABSTRACTThe structure of the cyst wall of the heliozoon Echinosphaerium nucleofilum has been investigated using light microscopy, scanning and transmission electron microscopy, and X‐ray microanalysis. The cyst wall is a composite structure of seven or eight layers. These are: an enveloping gelatinous layer; a layer of siliceous spheroidal bodies; an electron‐dense supporting membrane; a broad electron‐lucent zone; an electron‐dense layer; a layer of helicoidally packed material; and one or two layers with a granular appearance lying next to the plasma membrane of the encysted organism. The structure of the cyst wall closely resembles that of Actinophrys sol, confirming the close relationship of these actinophryid heliozoa while emphasizing their distinctiveness from other amoeboid protista.
Cell Surface Carbohydrates in Tritrichomonas foetus1
Authors: BENCHIMOL MARLENE , PEREIRA MIERCIO E. A. , ELIAS CEZAR A. , DE SOUZA WANDERLEY 
Published: May 2007

ABSTRACTThe cell surface of Tritrichomonas foetus was characterized by using 18 highly purified lectins with specificities for N‐acetyl glucosamine, N‐acetyl galactosamine, galactose, mannose, and sialic acid. The specificity of the lectin‐induced cell agglutination was verified by inhibition of the agglutination with the specific sugars. By using cytochemical techniques associated with electron microscopy, carbohydrates were detected on the cell surface of T. foetus. The following techniques were used: periodic acid‐thiosemicarbazide‐silver proteinate, concanavalin A‐horseradish peroxidase, and ruthenium red. Anionic sites were detected on the cell surface of the protozoan at pH's 1.8 and 7.2 with the use of colloidal iron hydroxide and cationized ferritin particles, respectively. The binding of colloidal iron particles, as well as the agglutination induced by the lectin from Limulus polyphemus, indicated the presence of sialic acid on the cell surface of T. foetus.
Formation of 2‐Aminobutanoic Acid from Threonine and Methionine by Mixed Rumen Ciliate Protozoa
Authors: ONODERA RYOJI , USHIJIMA TAKAYUKI 
Published: May 2007

ABSTRACTPrecursors of 2‐aminobutanoic acid (2‐ABA), found in the incubation medium of mixed rumen ciliate protozoa, were examined with washed or starved bacteria‐free ciliates. Threonine and methionine strongly stimulated the formation of 2‐ABA. Formation of 2‐ABA by direct conversion of threonine and dethiomethylation of methionine was confirmed by radiotracer experiments with [U‐14C]L‐threonine and [carboxyl‐14C] and [methyl‐14C]L‐methionine.
Trypanosoma cruzi: Biological Characterization of 19 Clones Derived from Two Chronic Chagasic Patients. I. Growth Kinetics in Liquid Medium1
Authors: ENGEL JUAN C. , DVORAK JAMES A. , SEGURA ELSA L. , CRANE MARK ST. J. 
Published: May 2007

ABSTRACTNineteen clones of Trypanosoma cruzi were obtained as single‐cell isolates from Triatoma infestans. Ten of the clones were isolates from a patient with chronic Chagas' disease; nine clones were isolates from a dog infected with T. cruzi strain CA‐I isolated originally from a chronic chagasic patient. The growth kinetics and peak modal Coulter volume of these clones were characterized. Significant inter‐ and intra‐group differences between growth rates and peak modal volumes were found. These data indicate that subpopulations and, consequently, genetic heterogeneity of T. cruzi exist in chronic chagasic patients. All of the clones infected vertebrate cells in vitro.