bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiple Alleles and Other Factors Affecting Plasmodium Formation in the True Slime Mold Physarum polycephalum Schw*
Authors: DEE JENNIFER 
Published: May 2007

SYNOPSIS. The life cycle of the true slime mold Physarum polycephalum includes 2 vegetative stages: the multinucleate coenocytic plasmodium and the uninucleate amoeba. A clone of amoebae established from a single spore does not normally yield plasmodia. Plasmodia are formed when amoebae from particular clones are mixed; thus plasmodium formation is said to be controlled by a ‘mating‐type’ system.Previous work by the author with a sample of P. polycephalum derived from a single source revealed that 2 mating types were present and were determined by a pair of alleles at 1 locus. The present paper reveals the presence of 2 more mating types in a sample of P. polycephalum derived from a different source and provides evidence that these are determined by 2 alleles at the same locus as the other 2.Evidence for the presence of other inherited factors affecting plasmodium formation, the mode of action of these factors and possible explanations for the occurrence of plasmodia in single‐spore cultures are also discussed.
Characterization and Localization of Acid Phosphatase Activity of Trypanosoma gambiense*
Authors: SEED JOHN RICHARD , BYRAM JAMES , GAM ALBERT A. 
Published: May 2007

SYNOPSIS. Properties and cellular location of acid phosphatase in Trypanosoma gambiense were studied. Activity was found in both the sediment (32,000 ×g) and the supernatant of homogenates. Cenrifugation in 0.3 M sucrose showed activity principally in the lowspeed fraction (4,000 ×g). One min of sonication released most of this activity. Several phosphomonoesters were hydrolyzed at acid H's. Enzymatic activity was relatively specific for pyrophosphate and p‐nitrophenylphosphate at pH 3.6. At pH 5.2, purine and pyimidine nucleotide 5′‐triphosphates as well as adenosine di‐ and ono‐5′‐phosphates were hydrolyzed nonspecifically. Activity with yrophosphate at pH 3.6 had a temperature optimum of 60‐70 C while that for adenosine 5′‐triphosphate (pH 5.2) was 50 C. These ctivities of the sediment required no metal co‐factors and were inibited by Fe++, inhibition at the lower pH being greater.Glucose 6‐phosphate was hydrolyzed by the supernatant with maximum activity between pH 6.0 and 7.2 and a temperature optimum of 50 C. This pH range showed a broad plateau with 2 or 3 minor peaks. The hydrolysis of p‐nitrophenylphosphate showed a similar pH curve. In glucose 6‐phosphate hydrolysis, Mg++ was a required co‐factor but could be replaced by Ni++ or Co++. Ammonium sulfate fractionation precipitated most of the supernatant activity between 50 and 75% saturation.A modified Gomori technic produced spherical deposits of PbS thruout the cytoplasm of the intact cell. With the electron microscope, Pb phosphate deposition was observed in membrane‐bound vesicles (i.e., lysosomes) approximately 100‐150 mμ in diameter. These organelles were common in the region of the reservoir at the base of the flagellum. Acid phosphatase activity specific for glucose 6‐phosphate as substrate was localized within this basal pocket.
Ultrastructural Observations on the Development of the Microsporidian Protozoon Plistophora hyphessobryconis Schaperclaus*
Authors: LOM JIRI , CORLISS JOHN O. 
Published: May 2007

SYNOPSIS. A sequence of developmental stages of Plistophora hyphessobryconis Schaperclaus, a microsporidian protozoan parasite of the muscular tissue of several species of freshwater fishes, was studied with the electron microscope. The youngest stages observed, ca. 4 × 2 μ, have a single nucleus and their plasm contains only ergastoplasmic lamellae and ribosomes. They are surrounded by a halo of lysed host tissue. They increase in volume to become large sporonts with a great number of nuclei and a thick, 2‐layered membrane. Thru schizogony, a corresponding number of sporoblasts is produced within this pansporoblast membrane. Sporoblasts start to develop a thick spore membrane, and a number of smooth‐membraned vesicles appear in the plasm. These vesicles fuse to make the outer membrane of the filament. Later, its inner structures originate—the axial electron‐dense substance, filling the hollow lumen of the filament, and a middle, electron‐transparent layer. The structure of the filament is discussed in relation to its function and with regard to the findings of other authors.The polaroplast is a laminated structure, originating possibly by transformation of endoplasmic reticulum; the polar cap forms its apical part. The cap is also lamellar; its substance reaches into the lumen of the filament for a certain distance. No micropyle was discovered in the shell; the filament is fastened to the polar cap. These observations on microsporidian development and on the structure of their spores are compared with similar data on myxosporidian species. Such a comparison speaks clearly in favor of the complete taxonomic separation of the Microsporidea from the Myxosporidea, the latter being quite different also from other sporozoa sensu lato.
Critical Phases of Oral Primordium Development in Tetrahymena pyriformis GL‐C: An Analysis Employing Low Temperature Treatment
Authors: FRANKEL JOSEPH 
Published: May 2007

SYNOPSIS. The effects of temperatures of 12–18 C on cell division and oral primordium development were investigated in cultures of synchronized Tetrahymena pyriformis GL‐C. If exposures to 12 or 15 C were initiated prior to a “transition point,” long delays of cell division were generated. After this transition point, cell division could no longer be substantially delayed by exposure to low temperature. The time of the transition point was somewhat earlier with 15 C than with 12 C treatments. At temperatures higher than 15 C long delays of cell division were not generated regardless of time of treatment.The effects of low temperature on oral morphogenesis were strongly dependent on the stage which was affected. (i) The further development of cells initially in the “anarchic field” stage (stage 1) was immediately blocked at both 12 and 15 C. (ii) Cells initially in the stages of incipient membranelle differentiation (stages 2 and 3) continued to develop at both 12 and 15 C, and formed oral primordia in which all 3 membranelles were clearly differentiated (stage 4). The subsequent progress of these stage 4 primordia depended on the temperature: at 12 C virtually all were resorbed (and cell division was blocked); at 15 C only about 1/3 were resorbed, while the remaining 2/3 completed their development (with the concomitant completion of cell division). (iii) Cells initially in intermediate stages of membranelle differentiation (early stage 4) developed to some extent at 12 C, and then underwent resorpton of oral primordia and blockage of cell division; at 15 C such cells completed their development and division normally. (iv) Cells in which the membranelles and undulating membrane were complete or nearly so (stage 5 and very late stage 4) at the time of the beginning of the cold treatment subsequently finished their development and went thru cell division, even at temperatures as low as 5 C.These results indicate that in addition to a “stabilization point” which occurs shortly before the completion of membranelle development, there is an earlier change in the primordium at the time of the onset of membranelle development, which renders development much less sensitive to direct interference by low temperature.
Infection of Macrophages in Culture by Leptomonads of Leishmania donovani
Authors: MILLER HAROLD C. , TWOHY DONALD W. 
Published: May 2007

SYNOPSIS. Peritoneal macrophages from hamsters were monolayered on coverslips in Leighton tubes. Twenty‐four hours later these were transferred to a perfusion chamber. Leptomonads were added with fresh medium and the infection process observed with the aid of phase contrast. In the perfusion chamber free‐swimming leptomonads attached to the macrophage by the tip of their flagella. Shortly after this initial attachment the macrophage extended a narrow pseudopodium around the flagellum which eventually reached and enveloped the body of the parasite. Upon complete envelopment the pseudopod containing the leptomonad was retracted into the central body of the macrophage. When first seen in the granular endoplasm of the macrophage, most of the leptomonads appeared to be surrounded by vacuoles. In most cases these vacuoles disappeared in a few minutes making it difficult to distinguish the parasite from the host cell cytoplasm.Leptomonads also were added directly to Leighton tube cultures, and the coverslips with the adherent macrophages and parasites were removed, fixed and stained periodically during the infection process. In these preparations most of the parasites were in clumps in the vicinity of macrophages. Details of the ingestion of the clumps could not be seen, but occasionally a single organism was seen with its flagellum and part of its body enclosed by an extended pseudopod. Most of the intracellular leptomonads were in large vacuoles. Forms intermediate between elongate leptomonads and LD bodies were surrounded by smaller vacuole‐like spaces. The halo‐like vacuoles most frequently seen around LD bodies may have been fixation artifacts. Under favorable conditions the leptomonads transformed to LD bodies in 1–4 hours, but it was 48 hours before a population increase could be found.
Generic Criteria for Flabellula, Rugipes and Hyalodiscus, With Descriptions of Species*
Authors: PAGE FREDERICK C. 
Published: May 2007

SYNOPSIS. Six strains of amoebae isolated from freshwater habitats and having broad, flattened locomotive forms were studied in clonal cultures, with attention to trophic structure, nuclear division, cyst structure in those strains which formed cysts, some aspects of cytochemistry, and other characteristics.Three strains were found to belong to the genus Flabellula, one being identified as F. platypodia (Gläser, 1912) and the other 2 as F. mira Schaeffer, 1926. The new species Rugipes placidus is described. One strain, identified as belonging to the species originally called Amoeba actinophora Auerbach, 1855, is re‐described as Hyalodiscus actinophorus, and a similar strain is described as H. actinophorus var. minor n. var.All 3 strains of Flabellula had the unusual type of mitotic figure reported by Gläser for F. platypodia but not previously studied with the Feulgen technic. The genus Rugipes has the mitotic pattern more common to small amoebae and is distinguished from Flabellula partly on that basis. Both strains of Hyalodiscus have division figures of this common type.Of the strains included in this investigation, only R. placidus and H. actinophorus formed cysts in culture. The cysts of neither species were viable after one year at room temperature and humidity.The status of Rugipes as distinct from Flabellula is discussed. The genus Hyalodiscus is interpreted in a manner compatible with the original definition of Hertwig and Lesser and is included within the order Amoebida. The strains of this genus isolated have a doubly contoured, strongly PAS‐positive covering over the endoplasmic hump.Some criteria for the taxonomy of amoebae are evaluated in the light of work reported in this and 2 previous papers.
Electron Microscopic Observations on the Symbiosis of Paramecium bursaria and its Intracellular Algae*
Authors: KARAKASHIAN STEPHEN J. , KARAKASHIAN MARLENE W. , RUDZINSKA MARIA A. 
Published: May 2007

SYNOPSIS. Observations were made on the fine structure of Paramecium bursaria and its intracellular Chlorella symbionts. Emphasis was placed on the structure of the algae and structural aspects of the relationship between the organisms.The algae are surrounded by a prominent cell wall and contain a cup‐shaped chloroplast which lies just beneath the plasma membrane. Within the cavity formed by the chloroplast are a large nucleus, a mitochondrion, one or more dictyosomes, and numerous ribosomes. The chloroplast itself is made up of a series of lamellar stacks each containing 2–6 or more thylakoids with a granular stroma and starch grains intercalated between the stacks. The thylakoid stacks of mature algae are frequently more compact than those of recently divided algae. A large pyrenoid is located within the base of the chloroplast. It is made up of a granular or fibrillar matrix surrounded by a shell of starch. The matrix is bisected by a stack of 2 thylakoids. Prior to the division of the chloroplast the pyrenoid regresses; pyrenoids subsequently form in the daughter chloroplasts thru condensation of the matrix material and the reappearance of a starch shell. This shell appears to be formed by the hollowing‐out of starch grains already present in the chloroplast stroma. Accordingly, in this case, starch moves from the stroma to the pyrenoid.The algae are located thruout the peripheral cytoplasm of the Paramecium. Each alga is located in an individual vacuole except immediately following division of the algae when the daughter cells are temporarily located in the vacuole which harbored the parental cell. Shortly thereafter the vacuole membrane invaginates, thereby isolating the daughter algae into individual vacuoles. Degenerating symbiotic algae are seen; because these are frequently found in vacuoles with bacteria, they are presumed to be undergoing digestion. Due to the conditions of culture these algae could have been either of intracellular or extracellular origin.
L'Organisation Ultrastructurale Corticale de la Gregarine Lecudina pellucida; ses Rapports avec l'Alimentation et la Locomotion
Authors: VIVIER E. 
Published: May 2007

SYNOPSIS. The structure of the cortical region (epicyte and ectoplasm) of the gregarine Lecudina pellucida, an intestinal parasite of the polychete worm Perinereis cultrifera was studied by electron microscopy.The epicitary folds have 3 unit type membranes. Between the 1st and 2nd is a layer probably composed of fine longitudinal fibrils which has an arch‐like or gutter‐like structure at the crest of the folds. Inside these folds is cytoplasm without any noticeable differentiation or inclusion except for a granular (or finely fibrillar) layer under the limiting inner membrane and close to it.The ectoplasmic zone of the entocyte is separated from the epicitary region by a lengthwise discontinuous cylindrical opaque layer, inwardly tangential to the folds. The ectoplasm lacks paraglycogen granules but has various organelles: apparently pinocytic vesicles against the wall between the folds, vesicles with myelinic membranes, opaque granules, a few mitochondria with blistered internal vesicles, and a few circular tubular fibers.The superficial zone of the gregarine is supposed to contribute to nutrition, thru the extensive surface furnished by its folds and thru the pinocytic vesicles; but this alimentary intake is incomplete compared with that of the previously studied anterior region.Insufficient mucus is discharged to account for locomotion. There are some circular ectoplasmic fibers, but locomotory myonemes are completely absent. However, there are deformations of the folds and corresponding waves that could account for locomotion by creeping or swimming. These movements of the folds might be due to the action of the contractile proteins and correspond with some of the layers seen in the wall.
Purine and Pyrimidine Synthesis by the Avian Malaria Parasite, Plasmodium lophurae*
Authors: WALSH CHARLES J. , SHERMAN IRWIN W. 
Published: May 2007

SYNOPSIS. Purine and pyrimidine biosynthesis in the avian malaria parasite Plasmodium lophurae and its host cell, the duck erythrocyte, were investigated in vitro. Pyrimidine synthesis, as measured by the incorporation of C14‐NaHCO3 into cytosine, uracil and thymine was slight in uninfected duck erythrocytes, whereas infected erythrocytes and erythrocyte‐free parasites had high rates of incorporation of NaHCO3 into these bases. In addition, orotidine‐5′‐monophosphate pyrophosphorylase and thymidylate synthetase, 2 enzymes of the pyrimidine biosynthetic pathway, were found in cell‐free extracts of the plasmodia. Purine synthesis was measured by determining the extent of incorporation of C14‐Na‐formate into adenine and guanine. Uninfected and infected erythrocytes had similar rates of Na‐formate incroporation into adenine. whereas free parasites incorporated little of this compound into adenine, or guanine. On the other hand, the incorporation of Na‐formate into guanine was 54% higher in infected erythrocytes than in uninfected erythrocytes.It is suggested that P. lophurae synthesizes purines to a limited extent, and derives most of its purines from the host erythrocyte. The greater incorporation of Na‐formate into guanine by infected cells, and its low incorporation into free parasites may be accounted for by parasite conversion of host cell adenine (in the form of ATP) into guanine. Pyrimidine biosynthesis in infected cells can be accounted for by de novo synthesis by the parasite itself.
Isolation of Toxoplasma gondii from the Feces of a Helminth Free Cat
Authors: DUBEY J. P. 
Published: May 2007

SYNOPSIS. Toxoplasma gondii was isolated from the feces of one of 2 cats infected orally with the Beverley strain of T. gondii.Toxoplasma gondii infects many species of warm blooded animals including man but its mode of transmission is not fully known. Congenital infection and cannibalism are the 2 accepted modes of transmission. Besides, nematode eggs have been suggested as another effective way of to transmission by Hutchison whose work has been reviewed in detail (5).
Circadian Rhythm of Pattern Formation in Populations of a Free‐Swimming Organism, Tetrahymena*
Authors: WILLE JOHN J. , EHRET CHARLES F. 
Published: May 2007

SYNOPSIS. In a preliminary search for a phototactic response in Tetrahymena, we discovered instead an autotactic phenomenon of pattern formation produced by motile free‐swimming cells in a dense culture. This pattern of cell aggregation is remarkably similar to the Bénard‐cell patterns of classical physical chemistry, and reminiscent of the streaming patterns of motile microorganisms.In a study of light effects on the rate of pattern formation, we found that it has an endogenous circadian component, and is strongly dependent on cell concentration.
Participation of the Undulating Membrane in the Formation of Oral Replacement Primordia in Tetrahymena pyriformis*
Authors: FRANKEL JOSEPH 
Published: May 2007

SYNOPSIS. Cells of T. pyriformis GL‐C, transferred from a complete axenic medium to a medium lacking amino acids, cease dividing after several hours, and instead begin to undergo oral replacement. This process can be synchronized by a single long 33.8 C treatment. Oral replacement was also observed during stationary phase of normal culture growth in cells of strain GL‐C and WH‐6 (syngen 1).In strain GL‐C the oral replacement primordium is initiated by the appearance of a small number of kinetosomes adjacent to the anterior end of kinety 1, just posterior to the undulating membrane (UM). The UM then loses its cilia and becomes disorganized, and is thus converted into a field of kinetosomes which is broadest near its posterior end. This UM‐derived field then becomes joined with the much smaller field which had appeared earlier near the anterior end of kinety 1. As a consequence, the right margin of the UM‐derived field becomes continuous with the anterior end of kinety 1, and thus comes to appear as an anterior extension of this kinety. The membranelles and UM of the new oral area differentiate within this composite field. While this is going on, the membranelles of the old oral area are progressively resorbed; these old membranelles always remain spatially separate from the oral replacement primordium.In strain WH‐6, the stomatogenic field initially formed adjacent to kinety 1 is substantial, and the role of the UM kinetosomes in stomatogenesis is less obvious than in strain GL‐C. The posterior portion of the UM probably contributes to the oral replacement primordium, while the anterior portion is resorbed. In this strain small supernumerary primordia are occasionally seen adjacent to the portion of kinety 2 which is nearest to the posterior region of the UM.It is suggested that the junction between the posterior portion of the UM and the neighboring cortex can serve as an inductive zone for initiation of stomatogenesis, the UM itself having a varying capacity for direct provision of kinetosomes for the stomatogenic field. The flexibility of the stomatogenic site in T. pyriformis is discussed in relation to the apparent restriction of potentialities in peniculine ciliates such as Paramecium.
Quelques Particularités Structurales de Cyanophora paradoxa Korsch., Protozoaire Flagellé
Authors: MIGNOT J. P. , JOYON L. , PRINGSHEIM E. G. 
Published: May 2007

SYNOPSIS. An electronmicroscopic study of Cyanophora paradoxa shows that its cuticle, vestibule, flagellar canals, and chondriome differ from those of Cryptomonadina. The flat cortical vesicles, peripheral tubules, as well as flagellar canals, which are surrounded by tubules, the anterior opening into an oblique depression and the posterior into a ventral groove, are more characteristic of Dinoflagellida. It is evident thus that, following Chadefaud, Cyanophora ought to be classified with primitive Dinoflagellida.Certain cytologic characteristics, especially the structure of the transitional zone (of the flagella), lead us to believe that Glaucocystis nostochinearum also belongs in this group.
Behavior and Pathogenicity of Tritrichomonas foetus in Chick Liver Cell Cultures*
Authors: KULDA JAROSLAV , HONIGBERG B. M. , Kulda Jelena 
Published: May 2007

SYNOPSIS. Clones of Tritrichomonas foetus, referred to as strains KV‐1, DK‐2, and UT‐1, which were judged by subcutaneous mouse assay to differ in pathogenicity, had different effects on trypsin‐dispersed liver cell cultures prepared from 3 lines (Light Brown Leghorn, Massachusetts Brown, Massachusetts Low Growth) of chicks. The general pattern of parasite‐cell interaction was similar in all cell cultures, but the intensity of certain responses of the cultures to trichomonads, reflected best in the levels of macrophage activity, depended on the line of chicks.The mild UT‐1 strain was readily engulfed and digested by the macrophages, caused very little damage to the epithelial cells and fibroblasts, and had a minimal inhibitory effect on the division rate of the latter. Many abnormal changes were seen, however, in the cytoplasm and nucleil of fibroblasts and epithelial cells in cultures exposed to strains of high (KV‐1) and intermediate (DK‐2) pathogenicity or to cell‐free filtrates of rich active cultures (henceforth referred to as filtrates) of these strains. The changes included retraction of cytoplasm which caused cell‐free spaces to appear in the sheets of fibroblasts and around the epithelial islands; the islands became detached from the surrounding fibroblast sheets and tended to form multilayered cell mounds. The flagellates and filtrates of KV‐1 strain greatly inhibited fibroblast division, and similar, but less pronounced, inhibitory effects were exerted by DK‐2 strain and its filtrates. Trichomonads of all 3 strains did not attach themselves to fibroblasts and epithelial cells. Thus the abnormal changes in cultures infected with KV‐1 and DK‐2 parasites apparently were caused by some toxic substances produced by the trichomonads, which had to be responsible also for the identical changes in cultures exposed to filtrates of these strains. KV‐1 and DK‐2 strains inhibited the phagocytic activity of the macrophages in the early stages of infection, the former causing stronger and longer lasting inhibition. Trichomonads of KV‐1 strain multiplied actively within the phagocytes which developed degenerative changes and ultimately burst, releasing healthy parasites into the medium. DK‐2 flagellates, altho incapable of dividing inside the macrophages, usually were not digested and caused degeneration of the cells which contained them.