bluuebunny/crossref_metadata_2025_split huggingface dataset:
La Spore des Actinomyxidies: Synactinomyxon longicauda n. sp., un Nouveau Type de Groupement Sporal et Adaptations Planctoniques: Emission et Structure du Sporoplasme1
Authors: ORMIERES A. MARQUES et R. 
Published: May 2007

RESUMEL'étude du caractère planctonique de différentes spores d'Actinomyxidies montre une complexité croissante dans leur adaptation au milieu aquatique. Au contact de l'eau, les trois cellules épéisporales de chaque spore se transforment en flotteurs de forme différente suivant les espèces. Ces flotteurs peuvent s'unir entre eux en un style équivelent à un quatrième flotteur ou associer diversement les huit spores issues d'un měme pansporocyste. C'est le cas dans le genre Synactinomyxon dont la diagnose est modifiée pour inclure une deuxième espèce S. Iongicauda n. sp. Un type nouveau est décrit chez lequel la preéence d'ancres à l'extrémité des cellules épisporales permet de maintenir efficacement réunies plusieurs dizaines de spores émises simultanément. Nous avons observé dans les genres Aurantiactinomyxon, Synactinomyxon, Echinactinomyxon l'emission du sporoplasme. II est libére en entier et capable de se déplacer dans l'eau pendant plus d'une heure grǎce à des mouvements amoeboïdes. Chez Aurantiactinomyxon eiseniellae les études ultrastructurales montrent que l'enveloppe du pansporocyste, d'une part, les épispores et les capsules polaires d'autre part sont réalisées à partir de cellules distinctes et profondément modifiées. Quant au sporoplasme, autrefois décrit comme un plasmode avec de nombreuses paires de noyaux, il contient, en fait, des ensembles identiques dont chacun est constitué de l'union d'un noyau satellite et d'une cellule uninucléée.ABSTRACTThe study of the planktonic character of different Actinomyxidia spores reveals increasingly complex adaptations to an aquatic environment. On contact with water, the three episporal cells of each spore transform into floats, the forms of which differ according to species. These floats can join together so that a fourth type of float is formed, or they can unite in various ways the eight spores originating from the same pansporocyst. This is the case in the genus Synactinomyxon whose diagnosis is modified to include a second species S. Iongicauda n. sp. A new type is described in which the presence of anchors at the extremities of the episporal cells permits several dozen spores that have been emitted simultaneously to be kept together. We have observed the emission of the sporoplasm in the genera Aurantiactinomyxon, Synactinomyxon, and Echinactinomyxon. It is freed completely and for more than an hour is capable of changing its position in the water by amoeboid movements. In the case of Aurantiactinomyxon eiseniellae, ultrastructural studies show that the pansporocyst envelope on the one hand, and the epispores and polar capsules on the other hand, are formed from separate but profoundly modified cells. The sporoplasm, however, sometimes described as a plasmodium with numerous pairs of nuclei, contains, in fact, identical complexes, each consisting of a uninucleate cell united with a satellite nucleus.
Growth Cycle‐Dependent Overproduction and Accumulation of Protoporphyrin IX in Tetrahymena: Effect of Heavy Metals1
Authors: RUBEN LARRY , LAGESON JEAN , HYZY BOB , HOOPER ALAN B. 
Published: May 2007

ABSTRACTCells of the ciliate Tetrahymena pyriformis GL overproduce and accumulate massive quantities of the heme intermediate, protoporphyrin IX. Protoporphyrin is localized intracellularly in discrete membranous compartments. The amount of porphyrin stored in the cell changes dramatically as cells progress through the growth cycle. Porphyrin overproduction is stimulated by δ‐aminolevulinic acid, but only during the mid‐stationary phase. Overproduction of protoporphyrin IX apparently results from an increase, late in the growth cycle, of activities subsequent to δ‐aminolevulinic acid synthetase. Feedback inhibition in the pathway by accumulated protoporphyrin IX does not occur. The presence of Co2+ completely inhibits accumulation of protoporphyrin IX in a manner reversed by δ‐aminolevulinic acid. Sn4+ stimulates protoporphyrin IX accumulation in the culture.
A Comparison of Growth Inhibition of Tetrahymena furgasoni by C19 and C21 Steroids
Authors: LAMONTAGNE N. S. , BROOKS J. M. , JOHNSON D. F. 
Published: May 2007

ABSTRACTThe growth inhibition of Tetrahymena furgasoni (once known as “T. pyriformis W”) by C19 and C21 steroids of similar structure was measured by determining cell population at 24 h and 48 h following addition of the steroid. A cis‐fusion of the A/B rings junction, unsaturation at C‐1,2, or C‐4,5 and carbonyl substitution all enhanced inhibition, whereas the presence of two hydroxyl groups decreased inhibition. The results indicated that the transformation of C19 and C21 steroids by this protozoon may be part of a detoxication mechanism.
Phospholipid Biosynthesis in Synchronous Plasmodium falciparum Cultures1
Authors: VIAL HENRI J. , THUET MONIQUE J. , PHILIPPOT JEAN R. 
Published: May 2007

ABSTRACTThe metabolism of phospholipids in synchronous Plasmodium falciparum‐infected erythrocytes was studied over one cycle of 48 h by the incorporation of labeled palmitate, serine, choline, and myo‐inositol into cellular lipids. The rates of incorporation of palmitate and serine into total phospholipids and of choline into phosphatidylcholine (PC) were linear with the maturation of the parasite, increasing by a factor of 2–5.6 according to the precursors. The rate of inositol incorporation into phosphatidylinositol was 9.6 times higher at the schizont stage than at the ring stage, with a marked increase in the second half of the cycle. A significant incorporation of palmitate into triglycerides also occurred during the schizont stage of the parasite. The incorporations of serine and palmitate into phosphatidylethanolamine (PE) and PC showed a net increase at approximately the twentieth hour of the cycle, while the radioactivities recovered in phosphatidylserine (PS) had already reached a maximum by this time. These findings indicate an instantaneous transformation of PS into PE and PC through a decarboxylation of PS into PE, then a methylation of PE into PC during the second half of the cycle. Although PS is a minor component of the Plasmodium parasite, our findings demonstrate the important role of this phospholipid as a precursor of PE and PC, which are major constituents of parasite phospholipids.
Morphogenetic Pattern in Laurentiella acuminata (Ciliophora, Hypotrichida): Its Significance for the Comprehension of Ontogeny and Phylogeny of Hypotrichous Ciliates1
Authors: MARTIN JESUS , FEDRIANI CONCEPCION , PEREZ‐SILVA JULIO 
Published: May 2007

ABSTRACTMorphogenetic events during division, physiological reorganization, and postraumatical regeneration, the last being induced both chemically and microsurgically, were studied by light microscopy on protargol‐impregnated specimens of the hypotrichous ciliate, Laurentiella acuminata. Parakinetal stomatogenesis, from transverse cirrus‐1 during division and reorganization, changes during regeneration to a parakinetal one which characterizes more primitive members of Hypotrichida in the S. O. Stichotrichina, but solely when the AZM is damaged. These morphogenetic events a) confirm the previous inclusion of L. acuminata among the Oxytrichidae on the basis of its morphological characters and indicate that it is a primitive species of this family related with the Stichotrichina through genera Pleurotricha and Paraurostyla; b) suggest a synthetic model that explains both the positioning and timing of cortical morphogenesis in the cell cycle. The key point of this model is the attribution to the AZM of a repressive capacity on the stomatogenic area, the last one being positioned according to the system of gradients of morphogenetic activity proposed by Jerka‐Dziadosz to explain location of primordia in urostylids. This repression is manifested not as a gradient, as indicated by De Terra, but as a long‐term repression limited to a certain distance. Simultaneous repression and stimulation occurring in a growing cortex with the AZM remaining constant in size could explain the critical ratio, buccal cortex/somatic cortex, at which stomatogenesis is triggered as indicated by De Terra.
Identification of the Immobilization Antigens of Paramecium by Their Cyanogen Bromide Cleavage Patterns1
Authors: SCHMIDT HELMUT J. 
Published: May 2007

ABSTRACTImmobilization antigens from 12 serotypes of three stocks of Paramecium tetraurelia and from one serotype of one stock of P. primaurelia were isolated and purified. Purified proteins were cleaved with cyanogen bromide, and the patterns of the fragment peptides were determined by electrophoresis on SDS‐polyacrylamide gels. It was shown that each of the serotypes of stock 51 of P. tetraurelia has an antigen that produces a characteristic and unique pattern. Consequently, the antigens can be identified by their patterns. Antigens from the allelic serotypes tested had identical patterns. The method is sensitive enough for the investigation of small sample volumes, and useful as a simple biochemical technique for the identification of serotypes.
Intracellular Bubble Formation: Differences in Gas Supersaturation Tolerances Between Tetrahymena and Euglena1
Authors: HEMMINGSEN BARBARA B. , HEMMINGSEN EDVARD A. 
Published: May 2007

ABSTRACTCells of Tetrahymena pyriformis, T. thermophila, and Euglena gracilis were saturated with nitrogen gas at pressures up to 300 atm and rapidly decompressed. Damage was assessed by measuring post‐decompression cell fragmentation or viability. Occurrence of intracellular bubbles was determined by cinephotomicrography performed during the decompression or by direct observations afterwards. The extreme gas supersaturations induced led to intracellular bubble formation and rupture in cells of Tetrahymena that contained food vacuoles, but only with supersaturations of 175 atm or higher; 225 atm left few cells intact. Bubbles were never observed in cells of Euglena or in Tetrahymena cells freed of food vacuoles, even when they were decompressed from substantially higher nitrogen supersaturations. Cells of Euglena were most resistant and were unaffected by supersaturations up to 250 atm.
Structure of Cyst Wall Precursors and Kinetics of Their Appearance During the Encystment of Laurentiella acuminata (Hypotrichida, Oxytrichidae)1
Authors: GUTIÉRREZ JUAN C. , TORRES A. , PEREZ‐SILVA J. 
Published: May 2007

ABSTRACTThe encystment of Laurenliella acuminata was divided into five stages: stage A (precystic semitransparent cell with dark‐globules), stage B (precystic transparent cell), stage C (precystic pigmented cell), stage D (spherical shape without cyst wall) and stage E (young resting cyst), on the basis of observations of changes in morphology and pigmentation during encystment. The duration of these stages was also established. Observations by electron microscopy confirmed that the cyst wall, composed of four layers, is derived from different kinds of precursors which are synthesized “de novo.” The ectocyst precursors are composed of stacks of between 5 and 12 small thin plates or discs; these stacks are about 0.9 μm in length and 0.06 μm in height. The mesocyst precursors are fibrillar bodies of variable shapes, about 2.4 μm in maximum length and 0.12–0.16 μm in diameter. These precursors appear in the cytoplasm of the precystic cell during the first precystic stage (stage A). The endocyst precursors are rounded bodies surrounded by a fine membrane, and their contents appeared similar to the endocyst. The granular layer precursors are spherical bodies about 0.1–0.2 μm in diameter, surrounded by a double membrane presenting ribosomes adhering to its outer membrane. Both endocyst and granular layer precursors are observed in the precystic cytoplasm from stage B. On the basis of ultrastructural studies, a formation and growth model of the cyst wall of the hypotrichous ciliate Laurentiella acuminata is proposed.
Characterization of Two Sibling Species of the Genus Stylonychia (Ciliata, Hypotricha): S. mytilus Ehrenberg, 1838 and S. lemnae n. sp. I. Morphology and Reproductive Behavior1
Authors: AMMERMANN DIETER , SCHLEGEL MARTIN 
Published: May 2007

ABSTRACTAll Stylonychia mytilus‐like ciliates which were collected and sent to us during the last 20 years belonged either to S. mytilus or to a new species, S. lemnae, which is described here. The only morphological differences are the shape and the size. Stylonychia mytilus that have been starved for one day average 300 μm in length, and S. lemnae starved for a day are 230 μm long. The occurrence of mating types is described.
Ultrastructural Observations on the Infection of Rat Liver by Plasmodium berghei Sporozoites In Vivo1
Authors: MEIS JACQUES F. G. M. , VERHAVE JAN PETER , JAP PAUL H. K. , SINDEN ROBERT E. , MEUWISSEN JOSEPH H. E. T. 
Published: May 2007

ABSTRACTThe invasion of liver parenchymal cells by sporozoites of Plasmodium berghei Vincke & Lips, 1948, was studied in vivo using transmission electron microscopy. Livers of Brown Norway rats were examined 30 and 60 min after intraportal injection of 15 million sporozoites each. Sporozoites found after incorporation into vacuoles in hepatocytes were often located near a bile canaliculus at the lateral cell surface, surrounded by hepatocyte lysosomal structures; however, degradation of sporozoites caused by lysosomal digestion inside hepatocytes was never observed. Due to the crescent shape of sporozoites, serial sections were necessary to demonstrate the actual process of invasion of the hepatocyte. The hepatocyte's plasmalemma appeared to invaginate due to the sporozoite's action, thereby creating a parasitophorous vacuole. It was suggested that the sporozoite actively penetrated the hepatocyte; however, no visible depletion of rhoptries and micronemes was observed.
Fine Structure and Cytochemistry of the Hydrogenosome of Tritrichomonas foetus1
Authors: BENCHIMOL MARLENE , SOUZA WANDERLEY DE 
Published: May 2007

ABSTRACTFine structural studies of the hydrogenosomes of Tritrichomonas foetus using an improved fixative reveal that they are enclosed by two closely apposed 6 nm membranes, which separate at some regions forming a large intramembranous vacuole where Ca++‐binding sites are located. Fixation of the cells in a glutaraldehyde solution containing 5 mM CaCl2 and postfixation in an osmium tetroxide‐potassium ferrocyanide solution led to the appearance of a reaction product associated with certain regions of the membrane of the hydrogenosomes and in the cisternae of the endoplasmic reticulum, in the recurrent flagellum, and in the plasma membrane. Treatment of ultrathin sections with EGTA removed the reaction product. These results, in association with others previously described, indicate the existence of several similarities between the hydrogenosomes and the mitochondria.
Electron Microscopic Observations of the Bloodstream Form of Cryptobia salmositica Katz, 1951 (Kinetoplastida: Bodonina)1
Authors: PATERSON W. BROCKLEY , WOO PATRICK T. K. 
Published: May 2007

ABSTRACTThe ultrastructure of the bloodstream form of Cryptobia salmositica in rainbow trout was examined during the acute phase of experimental infection. The arrangement of the major groupings of cytoplasmic microtubules originating near the basal bodies is similar to that in other bodonids. The cytostome is reinforced both by pellicular microtubules and an electron‐dense plaque. Certain microtubules associated with the flagellar pocket serve as nucleating sites for pellicular microtubules. A flagellar rootlet, consisting of two parallel fibers which are bound together intermittently by electron‐dense plaques, curves posteriorly from the basal body of the recurrent flagellum towards the kinetoplast. The basal body associated plaque on the kinetoplast membranes is duplicated at the same time as the basal bodies. Cytoplasmic microtubules are found in association with the plaque and the outer kinetoplastic membrane. A pulsatile vacuole, described for the first time in a hemoparasitic cryptobiid, lies adjacent to the post‐flagellar pit. Smaller, interconnected vesicles of the spongiome are continuous with the pulsatile vacuole. Since a pulsatile vacuole occurs not only in free‐living and ectoparasitic cryptobiids but in the hemoparasitic (=trypanoplasm) forms as well, this is no longer a character by which the genus Trypanoplasma may be separated from the genus Cryptobia. Possession of this osmoregulatory complex may allow the organism to survive outside of a host and fulfill a monoxenous life cycle, in addition to the usual heteroxenous cycle involving a leech as vector.
Transmission of Herpetomonas in Laboratory Populations of Drosophila melanogaster
Authors: ROWTON EDGAR D. , McGHEE R. BARCLAY 
Published: May 2007

ABSTRACTMethods of transmission and the effects of temperature and mites on ageledeme development of Herpetomonas were examined in populations of Drosophila melanogaster maintained in the laboratory. Herpetomonas was observed in feces of infected adults taken from population cages and in the vomitus of clean flies shortly after feeding on a saline suspension of flagellates. Free‐swimming flagellates were found in the moist areas of food cups. Adult D. melanogaster became infected when they fed on flagellates taken from the endoperitrophic space, the ectoperitrophic space or the Malpighian tubules.At 25°C the flagellates infected approximately 90% of the host population within 20 days. The high transmission rate was prematurely disrupted if host populations were subjected to changes in temperature. Free‐swimming flagellates did not appear to be affected at these temperature changes. Food mites (Tyrophagus) established in the growth media of the fly nearly eliminated the Herpetomonas from Drosophila populations.
Staining of Plasmodium yoelii‐Infected Mouse Erythrocytes with the Fluorescent Dye Rhodamine 1231
Authors: TANABE KAZUYUKI 
Published: May 2007

ABSTRACTThe cationic permeant fluorescent dye rhodamine 123 (R123) was used to stain Plasmodium yoelii‐infected mouse erythrocytes. Fluorescence microscopic observations demonstrated that the parasite, but not the matrix of the infected erythrocyte, accumulated the dye. Differences in fluorescence intensity could not be found at the various developmental stages of the parasite; however, quantitation of the cell‐associated dye revealed an increase in R123 uptake with parasite development. The retention of the parasite‐associated dye, as measured by fluorescence microscopy and spectrophotometry after extraction of R123 with butanol, was markedly reduced by treatment of the infected erythrocytes with a proton ionophore, carbonyl cyanide m‐chlorophenylhydrazone (CCCP), and an inhibitor of proton ATPase, dicyclohexylcarbodiimide (DCCD). These results indicate that the accumulation and retention of R123 in P. yoelii reflect the parasite membrane potential and suggest that the parasite plasma membrane has a membrane potential‐generating proton pump.
Multiple Fission in Allogromia sp., Strain NF (Foraminiferida): Release, Dispersal, and Ultrastructure of Offspring1
Authors: BOWSER SAMUEL S. , McGEE‐RUSSELL S. M. , RIEDER CONLY L. 
Published: May 2007

ABSTRACTThe release, dispersal, and ultrastructure of juveniles arising through multiple fission in the benthic foraminiferan Allogromia sp., strain NF (Lee & Pierce, 1963) has been examined by light and electron microscopy. An extensive reticulopodial network participates in the dispersal of fully differentiated young as they emerge from the fragmented parental test. During the earliest stages of release, offspring are of two classes—aroused and unaroused. Unaroused juveniles, which have not extended pseudopods, attach externally to the network and are transported bidirectionally along its surface. Aroused juveniles, which have extended pseudopods and are in protoplasmic continuity with the network, move quickly to the periphery of the network. Within 24 h, juveniles establish a communal “feeding reticulum” in which dispersed individuals are in protoplasmic continuity with neighbors via a common reticulopodial network. At the ultrastructural level, the cell body cytoplasm of unaroused juveniles contains numerous patches of a paracrystalline material, which disappears as their pseudopodia are extended to join the communal feeding reticulum. This paracrystalline material therefore appears to be a temporary reservoir of precursors required for pseudopod construction.
In Vitro Studies on the Biosynthesis of the Surface Glycoprotein of Trypanosoma congolense1,2
Authors: REINWALD ERWIN , HEIDRICH CLAUDIA , RISSE HANS‐JÖRG 
Published: May 2007

ABSTRACTTritiated leucine, glucosamine, mannose, and galactose were incorporated into the variant specific surface glycoprotein (VSG) of Trypanosoma congolense in vitro. The uptake of the precursors is shown by SDS‐polyacrylamide electrophoresis and fluorography, by assay of the radioactivity in immunoprecipitates obtained with specific antisera, and by the isolation of the labeled antigens by affinity chromatography on concanavalin A‐sepharose and isoelectric focusing. The in vitro labeled VSG exhibits the same degree of microheterogeneity as that observed in the VSG isolated from trypanosomes grown in animals. Analysis of the incorporated sugars after hydrolysis of the glycoprotein showed that glucosamine and mannose were utilized in biosynthesis of the carbohydrate moiety directly whereas galactose was converted possibly to other intermediates before being incorporated into the antigen. Tunicamycin completely prevented the incorporation of the radiolabeled sugars into the surface glycoprotein. The unglycosylated VSG with a molecular weight of 47 kDa had completely lost its size heterogeneity.
Lepidotrachelophyllum fornicis, n. g., n. sp., a Ciliate with an External Layer of Organic Scales (Ciliophora, Litostomatea, Haptoria)1
Authors: NICHOLLS K. H. , LYNN DENIS H. 
Published: May 2007

ABSTRACTLepidotrachelophyllum fornicis n. g., n. sp. was discovered in White Lake, Ontario, Canada, under winter ice. The genus is Trachelophyllum‐like, being highly flattened, elongate, and very extensible. The major feature that separates it from other genera in the family Trachelophyllidae is the presence of a dense layer of organic scales which covers the exterior of the cell and through which the cilia emerge. The scales are composed of filamentous material which is organized as an ovoid structure. The “rim” of the baseplate is formed of interwoven filaments. The baseplate is broken by circular or polygonal apertures. The same filaments form an arched superstructure broken by even larger, less regular apertures.
Trypanosoma lucknowi, a New Species of Trypanosome from Macaca mulatta with Observations on Its Fine Structure1
Authors: WEINMAN DAVID , WHITE ELIZABETH ANN , ANTIPA GREGORY A. 
Published: May 2007

ABSTRACTTrypanosoma lucknowi n. sp. was isolated in culture from one of 126 Macaca mulatta originating from the vicinity of Lucknow, Uttar Pradesh, India. Trypanosoma lucknowi is distinctive because of the large number of epimastigotes and trypomastigotes which, in culture, exhibit no movement or only a slight bending of the flagellar end. This limited motility coincides with a free flagellum which is either completely absent or rudimentary. The microorganism is cloned readily, and the description is based upon such cultures. Trypanosoma lucknowi shows pronounced differences from other trypanosomes of South Asian macaques and from “aflagellar” African trypanosomes. The ultrastructural demonstration of a cytostome and contractile vacuole suggests ultimate grouping with stercorarian trypanosomes. A 3‐D reconstruction of the flagellar pocket/cytostome region is included.