bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Fine Structure of Conidophrys pitelkae Bradbury Related to its Life Cycle and Taxonomic Position in the Apostomatida1
Authors: BRADBURY PHYLLIS CLARKE , TYSON GRETA E. 
Published: May 2007

ABSTRACTElectron microscopy of the tomite of Conidophrys pitelkae confirms that Jankowski was correct in including the pilisuctorians in the Apostomatida. Like other apostome tomites, the tomite of Conidophrys possesses a rosette opening to the exterior, kinetodesmata made up of stacks of individual kinetodesmal fibrils, and canaliculi that are surrounded by dense inclusion bodies and open on the ventral surface. The fine structure of the trophont of Conidophrys, however, is quite unlike that of other apostome trophonts. The elaborate infraciliature of the tomite disappears immediately after it settles and reappears de novo on the trophont just before tomitogenesis. The cyst wall, which completely encloses the trophont and grows with it, attaches the ciliate to a seta on its, host, the shrimp Crangon crangon. The setae on which tomites settle vary greatly in size and shape, but each appears to have at its tip some digitiform cuticular projections that surmount a pore, which opens into the lumen of the seta. The trophont's only direct connection to its host is at the cytostome, a unique structure formed of delicate tubules that pass through the pore into the lumen of the seta. Ingestion is by micropinocytosis, and there are no visible food reserves.
Ultrastructure of the Peritrich Ciliate Ambiphrya ameiuri and Its Attachment to the Gills of the Catfish Ictalurus punctatus1
Authors: FITZGERALD MALINDA E. C. , SIMCO BILL A. , COONS LEWIS B. 
Published: May 2007

ABSTRACTAmbiphrya ameiuri is an ectocommensal peritrich that attaches to the gills of warm‐water fishes and filters bacteria from the water. The ultrastructure of this protozoon, its attachment to the fish gills, and its effect on the gill tissue were investigated by scanning and transmission electron microscopy. The peritrich attached to the gills by fibers extending from the scopula. A microtubular array, apparently a barren kinetosome, was present in each lobular projection, but no scopular cilia were observed. At low densities Ambiphrya had no apparent harmful effects on the fish; however, at high densities respiration may be impeded. Ultrastructural studies indicate that this organism receives no nourishment from the host tissue.
Isolation and Properties of Isolated Nuclei from the Florida Red Tide Dinoflagellate Gymnodinium breve (Davis)1
Authors: RIZZO P. J. , JONES M. , RAY S. M. 
Published: May 2007

ABSTRACTA simple and rapid method is described for the isolation of nuclei from the Florida red tide dinoflagellate Gymnodinium breve. The nuclei are free of cytoplasmic contamination and are active in endogenous RNA synthesis. The ratio of DNA: RNA: acidsoluble protein: acid‐insoluble protein is 1:0.39:0.13:0.63, respectively, and each nucleus contains ca. 113 picograms of DNA. Electrophoretic analysis of the acid‐soluble proteins reveals the presence of two histone‐like proteins with molecular weights of 12,000 and 13,000.
A Comparison of Cortical Proteins in Tetrahymena vorax Microstomes and Macrostomes1
Authors: BUHSE HOWARD E. , WILLIAMS NORMAN E. 
Published: May 2007

ABSTRACTProteins of surface membranes and surface‐related cytoskeletons in Tetrahymena vorax microstomes and macrostomes were compared by one‐dimensional SDS polyacrylamide gel electrophoresis to see if protein differences could be detected that correlate with the transformation from one phenotype to the other. Some differences were observed. However, these alterations appear to result from the heat‐shock procedure used to synchronize the microstome‐to‐macrostome transition. The apparent lack of transformationspecific changes in cortical proteins is discussed. Similarities and differences between cytoskeletal proteins of T. pyriformis GL‐C and T. vorax are also noted and discussed.
Effect of Temperature and Osmolarity on Growth of Crithidia fasciculata, C. hutneri, C. luciliae thermophila, and Herpetomonas samuelpessoai1
Authors: SILVA JOÃO BATISTA TAVARES DA , ROITMAN ISAAC 
Published: May 2007

ABSTRACTCrithidia fasciculata (Anopheles, Culex, and Nöller strains), C. hutneri, C. luciliae thermophila, and Herpetomonas samuelpessoai were grown in a defined medium with different values of osmolarity at different temperatures. C. fasciculata (all strains) grew best between 300 to 500 mOsm; H. samuelpessoai, 400–500 mOsm; and C. hutneri and C. luciliae thermophila, 500–800 mOsm. At higher temperatures better growth was obtained at the upper osmolarities.
Mitochondrial Associations with Specific Components of the Cortex of Tetrahymena thermophila Nanney & McCoy, 1976: Microtubules and the Epiplasm1
Authors: AUFDERHEIDE KARL J. 
Published: May 2007

ABSTRACTUltrastructural observations of the cortically‐located mitochondria of Tetrahymena thermophila revealed associations not only between the mitochondria and certain of the cortical microtubule bands, but also between the mitochondria and the epiplasm of the cortex. Most of the distal mitochondrial surface is close and parallel to the epiplasm; favorable views show bridge‐like structures spanning the 20–10 nm gap between the mitochondrion and the epiplasm.Previous studies have shown that the placement of mitochondria in the cortex appears to be determined by certain of the cortical microtubule bands. This study, however, shows that mitochondrion‐microtubule interactions account for only a small proportion of the total mitochondrial area associated with the cortex; the rest is accounted for by the epiplasm. A possible analogue of the spectrin layer of erythrocyte membranes, the epiplasm may be important in helping to arrange the intricately organized components of the ciliate cortex. Its involvement in apparently helping to “moor” mitochondria to their cortical sites is the first suggestion of any role in cell patterning played by the epiplasm.
Further Observations on the Fine Structure of Acanthamoeba palestinensis (Reich, 1933). The Golgi Complex, Microbodies, and Mitochondria1
Authors: LASMAN M. , FEINSTEIN N. 
Published: May 2007

ABSTRACTThe fine structure of the trophozoite of Acanthamoeba palestinensis with a special emphasis on the Golgi complex, microbodies, and mitochondria has been examined. Golgi complexes are distributed throughout the cytoplasm but are most abundant in the perinuclear region. Usually two Goigi complexes are found in the same plane on opposite sides of the nucleus. One of them appears to be in an intimate association with the nuclear membrane. The region of contact contains compact cisternae, vesicles of various sizes, as well as granular and amorphous electron‐dense material. Structural changes in the nuclear envelope are also observed in this area. A structure consisting of a Golgi complex and electron‐dense microtubule organizing center, comparable to the centrosphere of other Acanthamoeba species, has been observed. Microbodies, surrounded by a single unit membrane and containing a granular matrix and tubular inclusions, are scattered throughout the cytoplasm. These organelles, circular (∼1 μm in diameter) or ovoidal (∼1 μm in length and ∼0.5 μm in width) in section, have often an irregular outline. These microbodies are probably the morphological equivalent of peroxisomes and glyoxysomes. Most mitochondria show a typical structure including tubular cristae and intracristal inclusions. Occasionally mitochondria with two apposed double membranes running through the midline are found. Such atypical cristae have never been reported in small amoebae before.
Ultrastructure of Mucocysts in Peranema trichophorum (Euglenophyceae)1
Authors: HILENSKI LULA L. , WALNE PATRICIA L. 
Published: May 2007

ABSTRACTThe “mucigenic” or “muciferous” bodies of Peranema trichophorum are further characterized here as unique extrusive organelles, the mucocysts. Intracellular and ejected mucocysts have characteristic shapes that may represent different developmental stages. Mucocysts found near the Golgi apparatus are membrane‐bounded, elongate, tubular structures with amorphous contents of low electron density. Subpellicular mucocysts are often aligned with pellicular striae and have dense contents, which are separated by an electron‐lucent zone from granular material at the tips. Ejected mucocysts are uniform in structure and consist of an inner tube with helical striations, an outer tube with a diamond‐shaped pattern, and a dense middle band. Fine fibrils, visible only after mucocyst discharge, emanate from the tips. Mucocysts may also protrude through the pellicle and discharge mucilaginous materials into the medium. Acid phosphatase activity is localized within the subpellicular mucocysts, suggesting that they may be involved in release of hydrolytic enzymes into the medium.
Presence of Amoebae in the Rhizosphere of a Beach Grass1
Authors: NAPOLITANO JOSEPH J. 
Published: May 2007

ABSTRACTThe occurrence of amoebae in the rhizosphere of a beach grass (Panicum sp.) collected at the Hempstead Lake State Park, Long Island, New York, was investigated throughout the growing season of 198 1. Amoebae achieved increased population density in the root system when compared with that in the surrounding bare sand; moreover, numbers of amoebae were higher only during the period of active plant growth and up to flowering. Following flowering, the numbers of amoebae in the root system fell to the level found in bare sand. The species diversity of amoebae in this system was compared with that in the carposphere of the mushroom Laccaria trullisata which appears at the same site but at a different time of year.
Fine‐structural Alterations in Leishmania tropica within Human Macrophages Exposed to Antileishmanial Drugs in Vitro1
Authors: LANGRETH SUSAN G , BERMAN JONATHAN D. , RIORDAN G. PATRICK , LEE LINDA S. 
Published: May 2007

ABSTRACTThe mechanism of action of antileishmanial compounds is poorly understood. Ultrastructural changes in Leishmania tropica within human macrophages exposed in vitro to Pentostam, pentamidine, amphotericin B, WR 6026, ketoconazole, and Formycin B were examined in these experiments. In Pentostam‐treated cultures, some organisms exhibited diminished definition of mitochondrial and other membranes, while other organisms had completely disintegrated. Pentostam‐exposed macrophages demonstrated loss of membrane definition in the absence of further alterations; it is therefore hypothesized that impaired macrophage membrane function may contribute towards the effect of this drug against macrophage‐contained organisms. Leishmania parasites in pentamidine‐treated cultures initially demonstrated swollen kinetoplasts and fragmentation of the kinetoplast DNA core. The initial observed effect of the other four drugs on the parasites was cytoplasmic condensation. These ultrastructural studies suggest that all five non‐antimonial drugs may have different mechanisms of action than antimony (Pentostam) against Leishmania.
Electrophoretic Mobility Patterns of Ribosomal Proteins as an Aid to Phenoset Classification of Amicronucleate Strains of Tetrahymena1
Authors: PETRIDOU BARBARA , CUNY MARGUERITE , HAYES FRANÇOISE 
Published: May 2007

ABSTRACTComparison of the electrophoretic migration patterns of proteins of active 40S and 60S ribosomal subunits isolated from nine amicronucleate strains of Tetrahymena of known phenoset revealed strain dependent differences which correlated with the phenoset classification of these strains as determined by Borden, Whitt & Nanney, who compared isoenzyme patterns.
Biochemical Approaches to Mating Type Expression in Tetrahymena thermophila1
Authors: VAN BELL CRAIG T. , WILLIAMS NORMAN E. 
Published: May 2007

ABSTRACTTwo‐dimensional gel electrophoresis was used to identify the patterns of protein synthesis during initiation, and the patterns of membrane protein expression following initiation, in all of the mating types of the Tetrahymena thermophila B family. In addition, one‐dimensional analysis was used to survey 125I‐Concanavalin A‐binding proteins. Although a large number of proteins was identified by each technique, no variation among the mating types was observed.
Conjugation Between G1and G2Phase Cells inParamecium tetraurelia1
Authors: MIWA ISOJI , UMEHARA NORITOSHI 
Published: May 2007

ABSTRACTCells ofParamecium tetraurelia, stock hrd, cultured in a micro‐capillary containing 1 μl fresh culture medium, expressed mating activity through the whole cell cycle. Mating‐reactive G2phase cells can conjugate with cells of other phases. The G2phase cells, which have double (4C) the normal micronuclear DNA content, undergo pre‐meiotic DNA synthesis when conjugated with G1phase cells. The micronucleus of the progeny from the cross between a G1and a G2cell becomes triploid.
On the Organization of the Naked Filose Amoeba, Nuclearia moebiusi Frenzel, 1897 (Sarcodina, Filosea) and Its Implications1
Authors: PATTERSON DAVID J. 
Published: May 2007

ABSTRACTThe ultrastructural organization of Nuclearia moebiusi is described. The organism has filose pseudopodia without supportive microtubules; it has mitochondria with flattened cristae, lacks extrusomes, microtubule‐organizing centers, and cytoplasmic microtubules. During cell division, microtubules appear only within the nucleus, and reorganization of the nuclear envelope occurs late in the nuclear division cycle. Ultrastructural studies reveal that Nuclearia spp. have a pattern of cellular organization distinct from that of other amoebae. Comparison of ultrastructural features suggests that this organism is only distantly related to other rhizopod amoebae (including other filose amoebae) and to the heliozoa.
Direct Transmission of a Hemoflagellate, Cryptobia salmositica (Kinetoplastida: Bodonina) Between Rainbow Trout Under Laboratory Conditions1
Authors: WOO PATRICK T. K. , WEHNERT SYBILLE D. 
Published: May 2007

ABSTRACTTransmission of Cryptobia salmositica occurred when infected and uninfected rainbow trout were held in the same tank. In tanks where infected and uninfected fish were allowed to mix freely, 67–80% of the uninfected fish acquired detectable infections by the 27th week. None of the control fish in another tank was infected. In another tank where the infected and uninfected fish were separated by a wire screen, 9 of 20 uninfected fish acquired detectable infections by the 22nd week. This is the first demonstration of direct transmission of a hemoflagellate via the water medium in aquatic vertebrates. Cryptobia salmositica was found in the mucus on the body surface of 9 of 10 fish examined 6 weeks after infection. These parasites were infective and some of them were morphologically similar to those in the blood or peritoneal fluid. It is suggested that the vascular species of Cryptobia were originally ectoparasitic on fishes and that these ectoparasitic species were descended from the free‐living Procryptobia.
Invasion of Babesia microti into Epithelial Cells of the Tick Gut1
Authors: RUDZINSKA MARIA A. , LEWENGRUB SONDRA , SPIELMAN ANDREW , PIESMAN JOSEPH 
Published: May 2007

ABSTRACTDuring feeding a peritrophic membrane (PM) is formed in the gut of the tick Ixodes dammini, dividing the lumen of the gut into an ecto‐ and endoperitrophic space. Babesia and all food particles ingested with the blood meal by the tick are retained in the endoperitrophic space, the lumen proper. Only Babesia equipped with a highly specialized organelle, the arrowhead, are able to pass the PM and enter the ectoperitrophic compartment. During the crossing of the PM the arrowhead loses its density, suggesting that enzymes released from it dissolve the polymers in the PM, making passage of the parasite through this barrier possible. In the ectoperitrophic space the arrowhead of Babesia touches the epithelial cell. At the point of contact the membrane of the host cell starts to invaginate, and simultaneously the arrowhead's fine structure loses its highly organized pattern. The growing host membrane encircles the parasite and the arrowhead diminishes progressively in size. When the piroplasm is inside the host cell, the arrowhead can no longer be found. During invasion the host membrane often touches the parasite's plasma membrane at the site of a coiled structure, and the host membrane becomes ruptured and the nearby host cytoplasm appears to be lysed. Babesia inside the host cell is covered solely by its own plasma membrane; the invaginated host membrane is missing. It is postulated that the latter disintegrates during invasion by the parasite through the action of enzymes from the coiled structure. The parasite is surrounded by a halo of homogeneous material deriving most probably from the lysed host cytoplasm.
Separation and Concentration of Schizonts of Plasmodium falciparum by Percoll Gradients1
Authors: RIVADENEIRA ENID M. , WASSERMAN MOISES , ESPINAL CARLOS T. 
Published: May 2007

ABSTRACTA technique for the separation of schizonts of Plasmodium falciparum is described. The different stages of the asexual cell cycle of the parasite were positioned according to their density in a continuous gradient of Percoll. Young trophozoites coincided with erythrocytes in a broad band corresponding to densities from 1.075 to 1.100 g/ml, whereas schizonts were concentrated at a density approximating 1.062 g/ml. The viability of the parasites was unimpaired by this procedure. Young trophozoites and schizonts continued their normal life cycle when cultured after the separation procedure. The percentage of recovery was high, reaching 80% of the initial quantity. Possible applications of the technique are discussed.
Isolation of Axopodial Axonemes from Mass‐cultured Echinosphaerium nucleofilum1
Authors: HOFFMAN EUGENE J. , PRICE DOUGLAS A. , KRUMPELMAN JAMES A. 
Published: May 2007

ABSTRACTThe heliozoan Echinosphaerium nucleofilum produced about 75 times 103 floating cells per 19‐cm culture dish per day when fed the green flagellate Chlorogonium elongatum. This method yields enough cells for usable quantities of subcellular fractions. Heliozoa were lysed in a detergent mixture containing stabilizing reagents, and axonemal bundles of axopodial microtubules were isolated from the lysate by differential centrifugation. Polyacrylamide gel electrophoresis in sodium dodecylsulfate showed two prominent bands tentatively designated alpha‐ and beta‐tubulin. Apparent molecular weights were 51.8 times 103 and 48.1 times 103, respectively. As assayed by electron microscopy of negatively stained whole mounts, the microtubule bundles splintered readily, although glycerol tended to inhibit this fraying. Intermicrotubule bridges could be observed in some axonemal splinters.
The Neutral Lipids of Paramecium tetraurelia: Changes with Culture Age and the Detection of Steryl Esters in Ciliary Membranes1
Authors: KANESHIRO EDNA S. , MEYER KANIAULONO B. , REESE MARY L. 
Published: May 2007

ABSTRACTNeutral lipids, particularly triglycerides, accounted for the major decrease in the total lipid content in Paramecium cells that occurs with culture age. Sterols, triglycerides, and steryl esters were the major classes of neutral lipids in cells and isolated cilia. Free as well as high concentrations of esterified sterols were detected in purified ciliary membrane preparations. Stigmasterol and 7‐dehydrostigmasterol were the major components of both free and esterified sterols of cells and cilia; however, when cholesterol was present in the growth medium, it was desaturated to 7‐dehydrocholesterol and incorporated into cellular and ciliary lipids. Free fatty acids from cells and triglycerides from cells and cilia were low in polyunsaturated fatty acids and reflected the composition of fatty acids in the culture medium. An exception was the reduced concentration of stearate in triglycerides from whole cells. Greater than 50% of triglyceride fatty acids from cilia were saturated. The fatty acid compositions of cellular triglycerides and ciliary steryl esters did not change with culture age, but those of cellular steryl esters and ciliary triglycerides did change. In comparison with phospholipids, these neutral lipid fatty acid compositional changes were smaller. The sensitivity of these stigmasterol‐containing cells to polyene antibiotics indicated that they were killed by nystatin > filipin > amphotericin B. The unexpected finding of high concentrations of steryl esters in ciliary membrane preparations is discussed.
The Pathogenic Amoeboflagellate Naegleria fowleri: Environmental Isolations, Competitors, Ecologic Interactions, and the Flagellate‐Empty Habitat Hypothesis1
Authors: GRIFFIN JOE L. 
Published: May 2007

ABSTRACTFrom several surveys of environmental sites, the virulent human pathogen, Naegleria fowleri, was isolated from a pond in Georgia, a sewage treatment plant in Missouri, and from the Potomac and Anacostia rivers near and in Washington, D.C. Widely scattered, sparse populations seemed only a potential threat to human health at the time of sampling. The data support an estimate that the sites sampled contain 10,000 typical, low temperature, bactivorous amoebae for each heat tolerant amoeba able to grow at 45° C. Heat tolerant competitors were much more common than N. fowleri. Naegleria lovaniensis, which is heat tolerant but nonpathogenic, was isolated from and downstream from an open air thermal pollution temperature gradient. Hot piles of composting sewage sludge yielded no amoeboflagellates, many heat tolerant (45–49° C) amoebae, and one thermophilic (52° C) Acanthamoeba. Features of the methods used include two‐stage incubation to increase isolation of sparse organisms and distinction of N. fowleri from almost all other amoebae on agar plates. The flagellate‐empty habitat hypothesis postulates a general model in which human intervention and/ or natural events remove usual competitors and the ability to transform to a motile flagellate confers an advantage in recolonizing.
True Intermediate Hosts for Eimeria funduli (Apicomplexa) from Estuarine Fishes1
Authors: FOURNIE JOHN W. , OVERSTREET ROBIN M. 
Published: May 2007

ABSTRACTGrass shrimp (Palaemonetes pugio) fed liver containing sporulated oocysts of Eimeria funduli permitted development of sporozoites that became infective to a variety of killifishes. The shrimp's gastric mill mechanically ruptured the oocysts. Sporozoites then excysted through an opening in the sporocyst, and by 12 and 13 h postinfection (p.i.) numerous empty sporocysts and free sporozoites occurred extracellularly in the intestine of the grass shrimp. Even at 5, 7, 8, 11, 46, 79, and 83 days p.i., and presumably for many months, numerous sporozoites still occurred free in the alimentary tract or between intestinal cells. The coccidium did not infect killifish at either 2 or 4 days p.i., but did at 5 days; after release from the sporocyst, it became more elongate with a distinct nucleus and two relatively large refractile bodies. Infections of E. funduli resulted in about one half of the fish that were fed either entire hepatopancreas or tips of hepatopancreas from experimentally infected shrimp. Feeding either the entire alimentary tract proximal to the first abdominal segment or any portion of that section from experimentally infected shrimp produced infections in nearly all tested fish. Feeding portions of the cephalothorax without any attached hepatopancreas or alimentary tract failed to produce an infection. Feeding killifish with wild grass shrimp from an enzootic area produced infections in only a fourth of the fish sample; however, feeding experimentally infected wild, laboratory‐reared, and juvenile grass shrimp produced infections in nearly all fish. Palaemonid shrimps other than P. pugio also can serve as intermediate hosts for E. funduli, and these shrimps include Palaemonetes vulgaris, P. paludosus, P. kadiakensis, and Macrobrachium ohione. In contrast, a penaeid shrimp, mysidacean, amphipod, and crab fed liver with sporulated oocysts did not produce infections when fed to killifish.