bluuebunny/crossref_metadata_2025 huggingface dataset:
Pyridoxine Kinase in Plasmodium lophurae and Duckling Erythrocytes*
Authors: PLATZER EDWARD G. , KASSIS JUDITH A.
Published: May 2007

SYNOPSIS. Pyridoxine kinase enzyme activity was greatly increased in duckling erythrocytes infected with Plasmodium lophurae. Pyridoxine kinase activity in parasites freed from erythrocytes was much greater than that of uninfected erythrocytes. The apparent Km for pyridoxine of the parasite enzyme was 6.6 × 10‐5 M whereas the host red cell enzyme Km was 1.9 × 10‐6 M. Deoxypyridoxine inhibited host and parasite pyridoxine kinase activity with an apparent Ki of 1.5 × 10‐6 and 8.6 × 10‐6 M, respectively. These results suggest that the vitamin B6 metabolism of the malaria parasites is distinct and separate from that of the host erythrocytes.
Fine Structure of Penetration of Cultured Cells by Isospora canis Sporozoites
Authors: JENSEN JAMES B. , EDGAR S. ALLEN
Published: May 2007

SYNOPSIS Monolayers of Embryonic Bovine Trachea (EBTr) cells were inoculated with Isospora canis Nemeséri spcrozoites. As penetration commenced, they were fixed, stained with OsO4‐ruthenium red, dehydrated, embedded and sectioned in situ. Examination by electron microscopy revealed that host cell membranes remained intact during penetration. The sporozoites caused an invagination of the cell's plasmalemma until the parasites were entirely within the cell, after which the invagination was sealed by short pseudopodia enclosing the parasite within a membrane‐lined vacuole inside the cells. Rhoptries and micronemes, which appeared as branched elements of the same network, became less tortuous near the conoid and often became empty or partially empty during penetration. Concurrent with the appearance of these partially empty rhoptries, vesiculations were seen in the host cell cytoplasm opposite the apical tip of the sporczoite. Constrictions of the sporozoite during entry were probably due to bands of microfilaments beneath the plasmalemma and elsewhere in the cytoplasm of the host cell.
Comparison of Singlet and Doublet Paramecium tetraurelia: DNA Content, Protein Content and the Cell Cycle*
Authors: MORTON GLENN T. , BERGER JAMES D.
Published: May 2007

SYNOPSIS Doublet Paramecium tetraurelia contain either a single macronucleus which is substantially larger than that in a singlet cell, or 2 smaller macronuclei. Doublets have approximately twice the DNA content and twice the total protein content of singlets. The cell cycle of doublets is 164% as long as that of singlets, but the relative position of the macronuclear DNA synthesis period within the cell cycle is the same as in singlets. The DNA content of doublets is regulated so that differences in the number of macronuclei do not produce corresponding changes in DNA content; bimacronucleate doublets have only 27% more DNA than unimacronucleate doublets.
Behavior of a Virus in a Symbiotic System, Paramecium bursaria—Zoochlorella
Authors: KAWAKAMI HISAKO , KAWAKAMI NOBORU
Published: May 2007

SYNOPSIS In a culture system of Paramecium bursaria, virus particles were found in large number. The particle was able to infect and multiply in certain cells of the zoochlorella, an intracellular symbiotic alga of P. bursaria. The infective particle, designated as zoochlorella cell virus (ZCV), was icosahedral and 120–180 nm in edge to edge diameter. The ZCV particle was found to differ from any of the already established viruses attacking the green and the blue‐green algae. Within the system where P. bursaria cells were growing, ZCV particles were detected in the depression of the pellicle, among the cilia growing in the cytopharynx, and in the food vacuole of P. bursaria. ZCV particles were infective only for the zoochlorella cells which were recently released from the cytoplasm of P. bursaria. The multiplication process of ZCV comprised the adsorption of the particle to the cell wall of the zoochlorella, the penetration of nucleic acid into the host cell interior, the replication of viral constituents, the maturation of viral particles and their final release by the burst of the zoochlorella cell. ZCV particles appeared only in the cytoplasmic region of the zoochlorella cell in which many ribosomes were distributed. A possible ecosystem among the 3 members consisting of P. bursaria, zoochlorella and ZCV is discussed.
Population Dynamics of Herpetomonas ampelophilae, with a Note on the Systematics of Herpetomonas from Drosophila spp.
Authors: ROWTON EDGAR D. , McGHEE R. BARCLAY
Published: May 2007

SYNOPSIS Previous surveys of feral Drosophila melanogaster in Clarke County, Georgia, indicated 10 to 30% of the flies were parasitized with Herpetomonas ampelophilae. In the present study, herpetomoniasis in D. melanogaster reared in population cages rose from 0.01% to 90% in 14 days. The infection fluctuated between 5% and 100% during the 250 days in which the ageledeme was maintained.

Herpetomonas were found endotrophically, peritrophically, and in the Malpighian tubules. In population cages, although there were sporadic rises in percentages, peritrophic and Malpighian tube infections usually remained low. Endotrophic infections often reached 100%, with individual flies being heavily parasitized. Although Chatton felt that several species of Herpetomonas inhabit a single species of Drosophila, we suggest that all the Herpetomonas in D. melanogaster be referred to as H. ampelophilae.
Mating‐Type Dependent Cell Pairing in Oxytricha hymenostoma: Macronuclear Fusion and Lack of Meiosis
Authors: ESPOSITO FULVIO , BANCHETTI ROSALBA , RICCI NICOLA
Published: May 2007

SYNOPSIS In a hologamy‐like process observed in Oxytricha hymenostoma, 2 cells belonging to complementary mating types fused and appeared to contribute equally to the macronuclei of the organism resulting from the fusion. The process was characterized by the absence of micronuclear division and by fusion of the macronuclei of the 2 partners. True conjugation involving micronuclear meiosis was not observed in O. hymenostoma. The biologic significance and the possible adaptive role of the hologamy‐like process are discussed.
Analysis of the Antigenic Composition of Trypanosoma brucei brucei Bloodstream and Culture Forms by the Quantitative Direct Fluorescent Antibody Methods*
Authors: STANLEY HAROLD A. , HONIGBERG B. M. , CUNNINGHAM ISABEL
Published: May 2007

SYNOPSIS The quantitative direct fluorescent antibody (QDFA) methods were employed for the antigenic analysis of bloodstream forms and culture procyclics of 2 variants, TRUM (Trypanosome Research University of Massachusetts) 106 and TRUM 107, of Trypanosoma brucei brucei. Intact and trypsinized trypanosomes were studied. It was demonstrated that: (A) The specific variant antigens are localized in the surface coat of bloodstream trypomastigotes. (B) In addition to the common antigens shared by bloodstream forms and culture procyclics, there are also certain antigens unique to these latter stages. (C) Still another group of antigens. not found in the culture procyclics, appears to be shared by the bloodstream forms, irrespective of their variant‐specific antigens. These antigens may be present in part in the coat or on the cell membrane and in part within the cytoplasm. (D) Irrespective of the bloodstream‐form variant from which they are derived, the procyclics are antigenically the same. The QDFA results are analyzed statistically and discussed in the light of the available literature.
Regulation of Macronuclear DNA Content in Tetrahymena thermophila*†
Authors: DOERDER F. P.
Published: May 2007

Synopsis.

Unequal macronuclear division in Tetrahymena thermophila introduces variance into G1 macronuclei; unless eliminated such variance would result in continuous variation in DNA content. Analysis of G1 and G2 macronuclear variances reveals that the added variance is eliminated by action on the extremes of macronuclear DNA content. In this model (Model II), macronuclei with small amounts of DNA have an additional complete S phase, while those with large amounts of DNA skip S. From available data, chromatin extrusion is shown not to contribute significantly, if at all, to the elimination of variance. Computer simulations utilizing haploid subunits indicate that model II predictions apply reasonably well to experimental data in terms of coefficients of variation, mean DNA content, and frequency of additional and skipped S phases. The simulations reveal also that within certain constraints, particularly the thresholds for additional and skipped S phases, macronuclear assortment is unaffected by Model II regulation. The relationships between Model II and other aspects of the cell cycle are briefly discussed.
Microscopic Observations on the Filopodia of Entamoeba histolytica*
Authors: LUSHBAUGH WILLIAM B. , PITTMAN FRED E.
Published: May 2007

SYNOPSIS

Living Entamoeba histolytica trophozoites were examined by phase‐contrast microscopy. Intact critical point dried trophozoites were examined by transmission electron microscopy at an accelerating voltage of 1000 kV (HVEM) and by scanning electron microscopy (SEM). Half and quarter m̈ thick sections of epoxy‐embedded trophozoites were examined by HVEM. Many of the trophozoites of 2 strains examined had surface filopodia, 1 to over 100 pan in length. The cytoplasm of filopodia was continuous with the cytoplasm and bounded by surface plasmalemma bearing a glycocalyx. Structures called “surface‐active lysosomes with trigger,”“dendritic plasmalemmal extensions,” and “extra‐amebic vesicles” by previous investigators probably represent portions of filopodia demonstrated in the present study. Filopodia appear to be of frequent normal occurrence in E. histolytica and may function in: (a) endocytosis or pinocytosis; (b) exocytosis; (c) attachment to substratum; (d) penetration of tissue; (e) release of cytotoxic substances; or (f) contact cytolysis of host cells.
Acetate Oxidation by Bloodstream Forms of Trypanosoma cruzi*
Authors: DOCAMPO ROBERTO , CRUZ FERNANDO S. , LEON WILSON , SCHMUNIS GABRIEL A.
Published: May 2007

SYNOPSIS

Bloodstream forms of Trypanosoma cruzi had a substantial increase in respiration in the presence of acetate. Oxidation of acetate took place via the tricarboxylic acid cycle and involved an antimycin A‐sensitive respiratory pathway. Oxygen uptake in the presence of acetate was as sensitive to antimycin A inhibition as was CO2 production. There was a 6–7% residual O2 uptake which was not inhibited by high antimycin concentrations. Human anti‐T. cruzi sera had no effect on oxygen uptake.
Preparation and Properties of Mitochondria from Naegleria gruberi*
Authors: WEIK R. R. , JOHN D. T.
Published: May 2007

SYNOPSIS

Whole cell respiration rates were measured polarographically for Naegleria gruberi during growth in agitated cultures. Log growth phase amebae consumed 80 ng atoms O/min/mg cell protein. At stationary phase, respiration rate decreased 4–fold. Intact mitochondria were isolated from N. gruberi and their oxidative and phosphorylative capacities were studied polarographically. As with the mammalian system, the mitochondria oxidized succinate and NAD‐linked substrates, but unlike rat liver mitochondria, those from the protozoan rapidly oxidized citrate and NADH. The rates of substrate oxidation were ADP‐dependent, with ADP:O ratios equalling ˜ 2.8 for NAD‐linked substrates and ˜ 2.2 for succinate. The respiratory control ratios. 2 to 4 for 11 substrates, were dependent on Pi, Mg2+, and serum albumin. Potassium cyanide, azide, malonale, and rotenone inhibited electron transport the same way as that of the mammalian system: however, amytal inhibited both glutamate and succinate respiration. Pentachlorophenol, DNP, and bilirubin uncoupled oxidation from phosphorylation. Difference spectra of oxidized and dithionite‐reduced mitochondria had distinct absorption bands of flavins and of c‐, b‐, and α‐type cytochromes.
Absolute DNA Determinations by Flow Microfluorometry
Authors: KEMPNER E. S. , DION R. L.
Published: May 2007

SYNOPSIS The DNA content of Euglena gracilis and murine leukemic cell line L‐1210 were varied by growth under abnormal conditions. DNA measurements by colorimetry and by flow microfluorometry were compared and absolute calibration of the flow device was established.
Evidence for NADH‐ and NADPH‐linked Glutamate Dehydrogenases in Trypanosoma cruzi Epimastigotes*
Authors: WALTER ROLF D. , EBERT FRANK
Published: May 2007

SYNOPSIS Two glutamate dehydrogenases, NADH‐linked (EC 1.2.1.2) and NADPH‐linked (EC 1.2.1.4.) were isolated from the epimastigote forms of Trypanosoma cruzi and purified. Both enzymes exist as hexamers. The molecular weights of the native NADH‐and NADPH‐linked glutamate dehydrogenases were estimated to be 360,000 and 265,000, respectively, and those of the subunits to be 58,000 and 43,000, respectively. The isoelectric point of the NADH‐linked dehydrogenase is at pH 5.25 and that of the NADPH‐linked enzyme at pH 5.1. The activities of both enzymes are regulated by product inhibition. In addition, purine nucleotides were shown to be potent inhibitors of the NADH‐linked glutamate dehydrogenase.
Biology and Structure of Phytomonas staheli sp. n., a Trypanosomatid Located in Sieve Tubes of Coconut and Oil Palms
Authors: MCGHEE R. BARCLAY , MCGHEE ANN H.
Published: May 2007

SYNOPSIS. Phytomonas staheli sp. n. is described from the oil palm (Elaeis guineensis) and the coconut palm (Cocos nucifera) of Surinam, South America. The phytomonad is the probable cause of “Hartrot” in the coconut palm and “Marchitez sopresiva” in oil palms. Parasites are confined to the sieve tubes in palms. Some success was obtained at cultivation of the organism from Elaeis.
Eimeria filamentifera sp. n. from the Snapping Turtle, Chelydra serpentina (Linné), in Iowa
Authors: WACHA RICHARD S. , CHRISTIANSEN JAMES L.
Published: May 2007

SYNOPSIS. Oocysts of Eimeria filamentifera sp. n. were isolated from 2 of 2 snapping turtles, Chelydra serpentina (Linné), in Iowa. The ovoid to ellipsoid oocysts of this species averaged 23.2 × 18.6 μm and had a length/width ratio ranging from 1.1 to 1.6. The ellipsoid sporocysts averaged 14.0 × 7.7 μm and had papillose, filament‐bearing Stieda bodies. Oocyst and sporocyst residua were present, but micropyle and polar granule were not. This appears to be the 2nd species of Eimeria reported from snapping turtles, with E. chelydrae being the first.
Changes in the Classification of Several Major Taxa of Ciliophora on the Basis of a Numerical Phenetic Analysis*,†
Authors: LYNN DENIS H.
Published: May 2007

SYNOPSIS. Several taxonomic problems arising from recent revisions of the phylum Ciliophora. Initially, electro‐ and light‐microscopic features of 7 species from 4 genera of colpodid ciliates were analyzed by several numerical phenetic procedures. The phenogram derived by using Jaccard's coefficient as the measure of similarity and the unweighted pair‐group arithmetic clustering method (UPGMA) yielded a classification with the highest cophenetic correlation coefficient.

Subsequently, relationships among 22 oligohymenophoran and related genera were determined by analyzing 57 ultrastructural and light‐microscopic features with Jaccard's coefficient and UPGMA. On the basis of these results, the suborder Peniculina is elevated to ordinal rank and the family Turaniellidae is transferred from the Peniculida to the Tetrahymenina. The phenogram also indicated that the nassuline ciliates may be allied with the OLIGOHYMENOPHORA rather than the KINETOFRAGMINOPHORA.
Development, Ultrastructure, and Mode of Transmission of Amblyospora sp. (Microspora) in the Mosquito*
Authors: ANDREADIS THEODORE G. , HALL DONALD W.
Published: May 2007

SYNOPSIS. Amblyospora sp. in Culex salinarius (Coquillett) is transovarially transmitted and has 2 developmental sequences, one in each host sex. In females, the entire life cycle is restricted to oenocytes which become greatly hypertrophied due to the multiplication of diplokaryotic cells during merogony and come to lie next to ovaries. Sporulation occurs only after a blood meal is taken and is shortly followed by infection of the oocytes and subsequent transmission to the next host generation. In the male host, infections spread from oenocytes to adipose tissue where diplokaryotic cells undergo a 2nd merogony. During this merognic cylce, the number of diplokaryotic cells greatly increases and the infection is spread throughout the body of the larval host. Sporulation is initiated with the physical separation of the 2 members of the diplokaryon and the simulatneous secretion of a pansporoblastic membrane. Subsequent meiotic division and morphogenesis result in the formation of 8 haploid spores enclosed with a pansporoblastic membrane. Buildup of spores and subsequent destruction of host adipose tissue prove fatal to the male host during the 4th larval stage.
Axenic Paramecium caudatum. I. Mass Culture and Structure*
Authors: FOK AGNES K. , ALLEN RICHARD D.
Published: May 2007

SYNOPSIS. To establish and grow Paramecium caudatum in mass axenic culture the culture medium of Soldo, Godoy & van Wagtendonk was modified by substituting phosphatidylethanolamine (PE) for TEM‐4T and by a 10‐fold increase in folic acid. Population densities of 4000 to 6000 cells/ml and a generation time of 20–26 h are regularly obtained. Optimal growth is obtained with PE‐stigmasterol ratios between 40:1 to 400:1. Cells from 1‐day‐old axenic cultures have many lipid bodies aggregated in clumps (which disappear in 2 to 3 days) as well as foci of rough endoplasmic reticulum bordered by dictyosomes. The latter suggests a very active metabolism. Crystalline sheets found in both food vacuoles and lysosomes presumably play a role in digestion. Axenically grown cells also have abundant Golgi bodies (dictyosomes) and by late log phase become filled with lysosomes.
Interactions of Pseudomonas Aeruginosa Hemagglutinins With Euglena Gracilis, Chlamydomonas Reinhardi, and Tetrahymena Pyriformis
Authors: SHARABI YEDIDA , GILBOA‐GARBER NECHAMA
Published: May 2007

SYNOPSIS The galactosephilic and mannosephilic hemagglutinins of Pseudomonas aeruginosa adsorbed onto Euglena gracilis, Chlamydomonas reinhardi, and Tetrahymena pyriformis. Furthermore, peroxidase binding to the 3 protozoan species was shown to be mediated by these lectins. Binding of Pseudomonas lectins to E. gracilis and C. reinhardi caused their specific agglutination, whereas no agglutination was observed with T. pyriformis, even after treatment by papain or by NaF. Added to the culture medium, the Pseudomonas hemagglutinins stimulated growth of E. gracilis and T. pyriformis due to their binding to these protozoa: this effect was partly inhibited by the specific sugar.
Multiconjugant Complexes of Euplotes Crassus: an Instance of Coordination of Nuclear Events*,†
Authors: LUPORINI PIERANGELO , GIACHETTI CINZIA
Published: May 2007

SYNOPSIS In the ciliate Euplotes crussus, doublet cells of 3 complementary mating types were mixed and multiconjugant complexes

obtained. The cells were not uniform in the G, stage at the time of mixing. Despite asynchrony, the nuclear events of conjugation

started and progressed coordinately in all the members of each complex, leading to a synchronous exchange of pronuclei. An adjustment

of the cellular timing takes place before the nuclei of multiconjugants begin dividing. This adjustment probably occurs through specific

ciliary contact during preconjugant interaction.
A New Method For Axenic Mass Cultivation of Paramecium Tetraurelia*
Authors: THIELE JÜRGEN , D̊ OTMAR HONER‐SCHMID , WAHL JÜRGEN , KLEEFELD GERTRUD , SCHULTZ JOACHIM
Published: May 2007

SYNOPSIS A method is described for the axenic mass cultivation of Paramecium tetraurelia strains 51s and 299s. the ciliate is grown in an enriched axenic medium developed by Soldo, Godoy & van Wagtendonk. Under continuous shaking on a rotary shaker, cultures were grown in one‐liter Erlenmeyer flasks with 330 ml medium yield cell densities of 32,000 cell/ml and 20,000 cells/ml for strains 299s and 51s respectively. Doubling time is considerably shorter under these conditions than in the conventional static cultures. A 20‐liter airlift bioreactor is described in detail which can be used successfully to otain up to 100 g wet weight of Paramecium in a single run; in this reactor the cell density reaches 38,000 cells/ml for strain 299s. and 23,000 cells/ml for 51s. This technic should facilitate the study of minor protein components of the ciliate.
Effects of Autogamy In Paramecium Tetraurelia On Catalase Activity and On Radiosensitivity to Natural Ionizing Radiations
Authors: CROUTE F. , DUPOUY D. , CHARLEY J. P. , SOLEILHAVOUP J. P. , PLANEL H.
Published: May 2007

SYNOPSIS Catalase activity of Paramecium tetraurelia decreased during autogamy and recovered to normal 5 days later. Autogamy also caused changes in the ciliate's sensitivity to natural ionizing radiations—the decrease in cell growth rate previously described in shielded cultures did not occur when autogamous cells were used. Maximum effect of shielding was observed in 11‐day‐old postautogamous cells. the role of the catalase in the mechanism of natural irradiation effect is discussed.
Prey‐Dependent Cell Size In A Protozoan Predator*
Authors: HEWETT STEVEN W.
Published: May 2007

SYNOPSIS. the cell size of Didinium nasutum was found to be dependent on the size of the Paramecium species available as prey. Didinium feeding on P. tetraurelia averaged 5.6 × 105μm3. the cell volume of Didinium increased with increasing prey size for the 5 prey species tested, to 9.1 × 105μm3 for Didinium feeding on P. caudatum. Didinium nearing a cell division ranged in size from 8.6 × 105μm3 on P. tetraurelia to 12.9 × 105μm3 on P. caudatum. the range in cell volume is such that Didinium feeding on P. caudatum are larger than the size at which Didinium divide when feeding on P. tetraurelia. This morphologic plasticity in cell volume allows Didinium to exploit a wide size range of Paramecium species as prey. It is proposed that the size of a Didinium may have profound effects on its ability to encounter and capture prey of different sizes.
Identification and Purification of an External Antigenic Glycoprotein (Immobilization Antigen) From Pseudomicrothorax Dubius
Authors: BOLIVAR IGNACIO
Published: May 2007

SYNOPSIS. A large, external glycoprotein with antigenic properties isolated from the ciliate Pseudomicrothorax dubius was found to have a molecular weight of ∼ 250,000 daltons. Analysis of the extracts by isoelectric focusing in combination with immunodiffusion and gradient polyacrylamide gel electrophoresis revealed that the principal antigen was a large glycoprotein. the glycoprotein was purified partially by Sephadex ultrafiltration. and almost completely by affinity chromatography on a concanavalin A‐Sepharose column.
Trypanosoma Cruzi: Pattern of Rna Synthesis Following Infection of Vertebrate Cells
Authors: ST J. CRANE MARK , DVORAK JAMES A.
Published: May 2007

SYNOPSIS. the pattern of RNA synthesis of intracellular Trypanosoma cruzi amastigotes, immediately following infection of Lesch‐Nyhan human fibroblasts, was studied by autoradiography. Amastigote RNA synthesis, determined by [3H]guanine incorporation, was not detected until 2 h after infection. At 8 h postinfection more than 90% of intracellular amastigotes were labeled. It was verified that extracellular trypomastigotes also synthesized RNA. Therefore it was concluded that, if RNA is required for trypomastigote‐to‐amastigote transformation, this nucleic acid is already present in the trypomastigotes before infection of the vertebrate cell. It is probable that the RNA synthesized by amastigotes during the prereplicative lag period (the period between initial infection and the onset of DNA synthesis) is required for intracellular growth and reproduction.
Production of Melanin Precursors By A Mutant of Tetrahymena Thermophila*
Authors: KANEY ANTHONY R. , KNOX GLEN W.
Published: May 2007

SYNOPSIS. A mutant of Tetrahymena thermophila. “pig,” excretes melanin precursors into the culture medium where spontaneous polymerization to melanin occurs. the precursors, probably oxidation products of catecholamines. are produced in large amounts by the mutant by decarboxylation of tyrosine and hydroxylation of the resulting tyramine. Overproduction and excretion of precursors by the mutant appears to result from elevated specific activity of L‐aromatic amino acid decarboxylase (DOPA decarboxylase) (E.C. 4.1.1.26).
Scanning Electron Microscopy of Spores of the Myxosporidans Chloromyxum Trijugum Kudo and Chloromyxum Catostomi Kudo*
Authors: LISTEBARGER JAMES K. , MITCHELL LAWRENCE G.
Published: May 2007

Spores of Chloromyxum trijugum Kudo from Lepomis macrochirus Rafinesque and Chloromyxum catostomi Kudo from Notropis dorsalis (Agassiz) were obtained from infected gall bladders, glass‐bead sonicated, and examined by scanning electron microscopy. Valves of C. trijugum spores each have a thick ridge running parallel to the sutural ridge. Uncapped cnidocyst pores open into the extrasutural ridges. A pyriform structure of unknown function was observed at the posterior surface in some spores. Spore valves of C. catostomi are sculptured with ridged striations running in various parallel and converging patterns over the entire surface. Cnidocyst pores open into ridges adjacent to the sutural plane. Glass bead sonication was found effective in polar filament extrusion. Discharged filaments were twisted along the long axis and partially coated with mucoid globules.
The Separation and Structure of Infective Trypanosomes From Cultures of Trypanosoma Brucei Grown In Association With Tsetse Fly Salivary Glands*
Authors: GARDINER P. R. , LAMONT LYNNE C. , JONES T. W. , CUNNINGHAM ISABEL
Published: May 2007

Infective trypanosomes developed when Trypanosoma brucei was cultivated at 28 C in a liquid medium containing tsetse fly head‐salivary gland explants. They were separated from the noninfective culture forms using DEAE‐cellulose column chromatog‐raphy. It was demonstrated by light and electron microscopy that the separated organisms were morphologically similar to metacyclic stages found in a tsetse fly and that they had a characteristic surface coat. Single metacyclic trypanosomes isolated from the cultures gave rise to infections in mice.
Sporozoites of Mammalian Malaria: Attachment To, Interiorization and Fate Within Macrophages
Authors: DANFORTH HARRY D. , AIKAWAD̊ MASAMICHI , COCHRANE ALAN H. , NUSSENZWEIG RUTH S.
Published: May 2007

Sporozoites of Plasmodium berghei and Plasmodium knowlesi, incubated in normal serum readily interact with peritoneal macrophages of mice or rhesus monkeys, respectively. Interiorization of the sporozoite requires that both serum and macrophages be obtained from an animal susceptible to infection by the malaria parasite. Serum requirements for sporozoite attachment to the macrophage are less specific. Phagocytosis is not essential for the parasites to become intracellular. Our findings indicate that active penetration of the sporozoites into the macrophages does occur.
Clonal Aging In Two Species of Spathidium (Ciliophora: Gymnostomatida)*
Authors: WILLIAMS DONALD B.
Published: May 2007

Thirty newly excysted Spathidium spathula (Müller) and 60 newly excysted Spathidium muscicola (Kahl) were selected as progenitors of clonal daily reisolation lines that omitted both conjugation and encystment. Daily division rates were determined for each clone either until it died or until the end of the 170 days of reisolation. Both species had reduced fission rates as they accumulated fissions in the absence of macronuclear reorganization. Spathidium spathula had a significant reduction of daily fission rate after 100‐120 fissions and S. muscicola after 20‐30 fissions. Older clones of both species contained a noticeable proportion of abnormal organisms. A significant increase (10.5%) in daily fission rate occurred in aged sublines of S. spathula following conjugation (selfing) and its concomitant nuclear reorganization. Spathidium muscicota did not conjugate, but recently excysted sublines, compared to aged lines, had an increased daily fission rate.
Structure of Mitochondrial Dna From Paramecium Tetraurelia*
Authors: FINDLY R. CRAIG , GALL JOSEPH G.
Published: May 2007

Mitochondrial DNA (mtDNA) from endosymbiote‐free stocks of Paramecium tetraurelia was isolated by 2 procedures. the buoyant density of the mtDNA in neutral CsCI was 1.702 gm/cm3. a value consistent with the melting temperature of the mtDNA. Only linear molecules were observed by electron microscopy. These molecules were homogeneous in size with a monomer molecular weight of 25.6 × 106 daltons. the size of the mtDNA determined after digestion with the restriction endonucleases EcoRI or Hind III agreed with the value obtained by electron microscopy. These studies also revealed that the digestion pattern of mtDNA from stock 172 differed from that of the other 3 stocks (51, 127. 203) examined. Some mtDNA molecules exhibited snapback reassociation following denaturation.
Structural Changes in Tetrahymena rostrata during Induced Encystment*
Authors: McARDLE EUGENE W. , BERGQUIST BARTON L. , EHRET CHARLES F.
Published: May 2007

SYNOPSIS. Experimentally induced precystic stages and mature cysts from 3 clones of Tetrahymena rostrata were examined by light and electron microscopy. It was demonstrated by cytochemical staining and fine‐structural observations that precystic stages release mucocyst material that provides for the production of a cyst wall. Early and late cysts also contain numerous autophagous vacuoles. In late cysts there is a replacement of depleted mucocyst organelles. The developmental evidence obtained from sampling of sequential developmental stages suggests an ∼24‐h timetable of cytoplasmic events associated with encystment in this organism.
Torsional Movements in the Ameba, Chaos carolinensis, Suggest a Helical Cytoskeletal Organization*†
Authors: BYNUM R. D. , ALLEN‡ R. D.
Published: May 2007

SYNOPSIS. Centrifugation for 30–40 seconds at 8,000 g has been used to render monopodial specimens of the large free‐living ameba. Chaos carolinensis. These monopodial amebae exhibit obvious torsional movements in the tail. In many cases the posterior ectoplasm assumes the form of a screw with helical ridges forming in place of the more common straight dorsal fins. This finding prompted a re‐examination of normal polypodial C. carolinensis, and a majority of these were found also to exhibit torsional movement in the tail and in retracting pseudopodia. These movements suggest that the cytoskeleton of Chaos may have a helical component in its organization.
Studies on the Macronuclei of Doublet Paramecium tetraurelia: Distribution of Macronuclei and DNA at Fission*
Authors: BERGER JAMES D. , MORTON GLENN T.
Published: May 2007

SYNOPSIS. Doublet Paramecium tetraurelia would be expected to contain 2 macronuclei if their nuclear complement were strictly analogous to that of singlets. However, most doublets are unimacronucleate. It is shown in this study that dimacronucleate cells are present only in young clones. Unimacronucleate cells arise either through abnormalities in the determination and distribution of macronuclear anlagen during the first cell cycle after conjugation, or from dimacronucleate cells through abnormal division and segregation of macronuclei during the fission process.

When a change in the number of macronuclei occurs through abnormalities in the division and segregation of daughter macronuclei, the daughter cells produced typically have DNA contents more similar than those expected from either random segregation of daughter macronuclei, or from the normal segregation pattern in ciliates in which changes in the number of macronuclei in progeny cells do not occur. This suggests that part of the regulation process of macronuclear DNA content in Paramecium may occur through control of the segregation pattern of daughter macronuclei.
Comparison of DNAs of Crypthecodinium cohnii‐like Dinoflagellates from Widespread Geographic Locations*
Authors: STEELE ROBERT E. , RAE PETER M. M.
Published: May 2007

SYNOPSIS. We have examined various properties of DNAs from 7 dinoflagellate isolates of wide geographic distribution; all of the isolates are superficially indistinguishable from a laboratory strain of Crypthecodinium cohnii originally isolated at Woods Hole, Massachusetts (WHd strain). Two isolates, one from Puerto Rico and the other from Honduras, are clearly distinguishable from WHd and the other isolates by their DNA buoyant density values. WHd and the other 5 isolates we have examined are indistinguishable from one another in terms of DNA buoyant densities and melting temperatures. The relationship among the various isolates, including WHd, were evaluated at a finer level through restriction endonuclease cleavage and molecular hybridization to compare ribosomal RNA gene structure in the several DNAs. All the isolates could be further categorized by this method, the patterns of restriction endonuclease cleavage of ribosomal RNA genes in the isolates paralleling exactly their sexual compatibilities established from breeding experiments by Beam & Himes. The DNAs were also treated with a restriction endonuclease sensitive to the presence of the modified base 5‐methylcytosine. In all isolates, cytosine residues in both total DNA and DNA specifically containing the ribosomal RNA genes were found to be extensively methylated, as was previously shown for the WHd strain.
Protist Biogeography1
Authors: BAMFORTH STUART S.
Published: May 2007

Autecology (cellular organelles and secretions, encystment and dispersal abilities), environmental conditions (physiological tolerances and interaction with other organisms), and evolutionary history contribute to protist biogeography, which manifests ecological and historical aspects. Ecological biogeography is seen in the influence of geochemistry on the distribution of fresh‐water phytoflagellates and algae, and of moisture and vegetation type on soil‐litter protists. A temporal feature is often present because many protists encyst and respond only to certain ranges of temperature and organic content. Historical biogeography has occurred by radiative host evolution on symbiotic protozoa (e.g., termite flagellates and rumen ciliates), and by the isolating effects of water currents, temperature, and density gradients on oceanic protists (coccoliths, dinoflagellates, foraminifera, radiolaria, and tintinnines). These two aspects combine in protists living on animal surfaces. Humans affect protist biogeography by increasing parasite ranges through human migrations and by water pollution. They can diminish these situations by disease control and exploiting appropriate ciliates in sewage disposal. Many free‐living protozoa appear to be cosmopolitan, but mating types and isoenzyme studies suggest that speciation with its geographic connotations may be more widespread than presently appreciated.
Aufwuchs Protozoa and Bacteria on the Gills of the Rock Crab, Cancer irroratus Say: A Survey by Light and Electron Microscopy1
Authors: BODAMMER JOEL E. , SAWYER THOMAS K.
Published: May 2007

Histological examination of gills of the rock crab (Cancer irroratus Say, 1917) taken from specimens collected in polluted and nonpolluted areas indicated that gill discoloration was not directly related to the degree of microbial fouling. Light microscope studies demonstrated that bacteria, peritrich and suctorian ciliates, and some naviculoid diatoms were the principal members of the fouling community. Examination of the bacteria by electron microscopy showed that several distinct types were present, and that some of these were attached to the gill by holdfast structures while others were enmeshed in a filamentous slime layer. An unusual small marine flagellate and an unidentified amoeba were also examined ultrastructurally.
Mitosis of Micronuclei During Division and Regeneration in the Ciliate Stentor coeruleus1
Authors: RAIKHEL NATASHA , PAULIN JEROME J. , SKARLATO SERGE O.
Published: May 2007

Stages of mitosis of the micronuclei of Stentor coeruleus were described as seen by transmission electron microscopy. Cells in division and those regenerating new oral membranelles were studied. Microtubules were found in early prophase in the karyoplasm and interspersed between the condensing chromatin. A monaxial intranuclear spindle is formed by early metaphase, with kinetochore microtubule attachment sites on the chromosomes. The spindle elongates, separating the daughter nuclei at anaphase. A new nuclear envelope, consisting of two unit membranes, begins to form at late anaphase. Small segments of membrane found in the space between the newly forming and the old micronuclear envelopes appear to fuse to form the new nuclear envelope. No ultrastructural differences were found in the mitotic nuclei of cells in division or regeneration.
Electrically Induced Tentacle Retraction in the Suctorian Protozoon Discophrya collini (Root)1
Authors: HACKNEY CAROLE M. , BUTLER R. D.
Published: May 2007

Discophrya collini is a free‐living suctorian with retractile tentacles covered by a thick fibrous cortex. The tentacles contain a microtubular central canal surrounded at the base by a fibrous collar. Electrical stimulation induces a reproducible tentacle retraction. With extracellular electrodes, the tentacles nearest the anode respond initially, contracting by up to 75% of their original length. There is an inverse relationship between voltage level and duration of stimulus in producing a threshold response, and at a set voltage, between duration and degree of retraction. With intracellular electrodes, the membrane potential has been measured as ‐30 mV, and tentacle retraction occurs in response to as little as 1.25 nA when the intracellular electrode is made the cathode of the circuit. SEM studies show that retracted tentacles have a wrinkled cortex, while TEM shows that the microtubular canal bends as it enters the cytoplasm. No consistent changes occur in the microtubule configuration of the canal on retraction, suggesting that the microtubules are not directly involved in the contractile mechanism.
Identification of Surface Proteins on Viable Plasmodium knowlesi Merozoites
Authors: JOHNSON JAMES G. , EPSTEIN NAVA , SHIROISHI TSUGIYE , MILLER LOUIS H.
Published: May 2007

Viable merozoites of Plasmodium knowlesi were isolated and the proteins that were labeled on intact merozoites by lactoperoxidase‐catalyzed radioiodination were identified. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography of Triton soluble extracts of labeled merozoites demonstrated eight major bands ranging in apparent molecular weight from 150,000 D to 22,000 D. Exposure of intact merozoites to trypsin (10 μg/ml) for 10 min resulted in the loss of the two highest molecular weight proteins (150,000 D and 105,000 D) and the appearance of two new bands at 70,000 D and 62,000 D. Trypsin treatment under these conditions also removed the receptor(s) for merozoite attachment to erythrocytes. Therefore, these high molecular weight proteins are candidates for the merozoite component that attaches to erythrocytes. There was no evidence that the labeled membrane components were serum or erythrocyte membrane components, two potential contaminants in the preparation. Anti‐rhesus erythrocyte antibody did not precipitate labeled merozoite proteins. Furthermore, the immunoprecipitation of labeled merozoite proteins by rhesus anti‐merozoite serum was not inhibited by erythrocyte ghosts.
Kinetoplast DNA in Trypanosoma equinum1
Authors: CUTHBERTSON ROBIN SHERYL
Published: May 2007

Identification and characterization of kDNA is described in the naturally occurring totally dyskinetoplastic species Trypanosoma equinum. Fluorescence microscopy of live cells, using the highly sensitive and specific probe DAPI (4,6,‐diamidino‐2‐phenyl‐indole), showed the presence of a diversity of extranuclear fluorescent bodies scattered along the length of the organism. Transmission electron microscopic studies revealed a close similarity between the distribution of these DAPI‐fluorescing particles and of dense aggregates of nonfibrillar material resembling the kDNA of dyskinetoplastic strains of other species. Variable sized remnants of kDNA, occurring singly or in clusters, were found scattered throughout the mitochondrion. Analytical cesium chloride ultracentrifugation of total cellular DNA extracts showed a kDNA banding profile at a buoyant density equal to 1.691 gm/cm3, representing approximately 11% of the total cellular DNA content. Molecular spreads of isolated kDNA revealed a population of open circular molecules ranging in contour length from 0.11–9.69 μm.
Morphogenesis in Conchophthirus curtus: a Study of the Morphological Events Associated with Binary Fission1
Authors: ANTIPA GREGORY A. , HATZIDIMITRIOU GEORGE
Published: May 2007

Morphogenesis in Conchophthirus curtus has been investigated by the use of protargol silver impregnation supplemented by selective use of scanning electron microscopy. Events are assigned to nine sequential stages; the last, stage 9, which involves maturation of the somatic ciliature and infraciliature as well as the final development of the buccal cavities of both proter and opisthe, occurs following cytokinesis. Stomatogenesis involves both the parental haplokinety and the deep kinetosomal unit (DKU). In perhaps a unique phenomenon, phylogenetically, the ciliated parental haplokinety forms the early oral primordium of the opisthe and is replaced in the proter by the DKU. The DKU then acts as a formative center for new kinetosomes that migrate into the developing opisthe primordium. Late in the process, the haplokinetal primordia of both proter and opisthe give rise to their respective DKU's. Some events of nuclear activity and somatic development are also described. The high degree of structural differentiation of this ciliate has provided the opportunity to examine temporal relationships during morphogenesis. We have found that somatic, buccal, and nuclear events proceed in a tightly coupled sequence. Hence, somatic and nuclear development can be directly correlated with the nine stages of stomatogenesis.
The Cortical Morphogenetic Cycle Associated with Cell Division in Diophrys Dujardin, 1841 (Ciliophora, Hypotrichida)1
Authors: HILL BRUCE E.
Published: May 2007

Morphogenesis of cell division was investigated in Diophrys scutum, D. oligothrix, and D. appendiculata utilizing both light microscopy of living and stained specimens and SEM of preserved specimens. The cortical morphogenetic pattern of Diophrys is similar to that of other members of the family Euplotidae. The opisthe oral primordium, which develops in a subsurface pouch, forms posterior to the parental buccal cavity. The proter inherits the parental adoral zone of membranelles (AZM) apparently unchanged. The endoral membrane forms to the right of the posterior end of the AZM in the proter, in association with the developing AZM in the opisthe. The paroral cirrus and membrane develop from a single streak that first appears along the right edge of the buccal cavity in the proter to the right of the developing buccal structures of the opisthe. Frontal and transverse cirri develop in both proter and opisthe from five separate cirral primordia that form to the right of the buccal cavity. Left marginal cirri do not develop in association with the corresponding parental structures. Kinetosomes formed within the opisthe oral primordium, or kinetosomes that were part of any parental ciliary structure, do not appear to become part of any developing paroral structures, frontal, transverse, or left marginal cirri. Speciation within the genus Diophrys and evolution of the family Euplotidae as they relate to the morphogenesis of cortical structure are discussed.
Species of Eimeria in Nonepithelial Sites1
Authors: OVERSTREET ROBIN M.
Published: May 2007

In a few homoiothermic host species, Eimeria spp. in a schizogonic stage, a gamogonic stage, or as resting sporozoites infect nonepithelial tissues. However, epithelium serves as a critical site in the cycle of these and all other species known from warm‐blooded hosts. Eimeria funduli, infecting at least four different killifishes, undergoes both schizogony and gamogony in non‐epithelial hepatic and pancreatic cells and requires an invertebrate host to complete its cycle. Oocysts are not released from the living fish into the environment. The cycle for this species, or aspects of it, may exemplify those found in several piscine species infecting nonepithelial (and possibly epithelial) cells. Eimeriu funduli differs from most species of Eimeria infecting homoiotherms in other respects, some of which may also characterize traits for piscine and other poikilotherm eimerians in general. Endogenous development is affected by temperature and host‐age, sporogony occurs in the host, and infections occur in several related fishes. The presence of an intermediate host in at least E. funduli and the presence of sporozoites in macrophages of several eimerians of homoiotherms, as well as other features, suggest a closer relationship between eimeriids and Lankesterella, Schellackia, and even the Haemosporina than previously assumed.
The Sarcocystidae: Sarcocystis, Frenkelia, Toxoplasma, Besnoitia, Hammondia, and Cystoisospora1
Authors: SMITH DONALD D.
Published: May 2007

Members of the family Sarcocystidae, as defined by Frenkel, have had a complicated history, principally due to the existence of both coccidial and cystic stages. This formerly clandestine relationship resulted in dual or partial designations of nomenclature for individual species. The problem was further compounded by the obligatory heteroxeny of several of the genera, making it impossible to transmit the parasites from one individual to another of a single host. As a result, oocysts similar in appearance, though from hosts separated taxonomically up to the familial level, were sometimes considered to be identical. Discoveries within the last decade have generated much interest and some understanding. Current studies of these and other coccidia should emphasize complete cyclical transmissions with cognizance of potential heteroxeny with the production of tissue cysts in intermediate hosts.
Coccidian Taxonomy and Nomenclature1
Authors: FAYER RONALD
Published: May 2007

Problems of the taxonomy and, especially, of the nomenclature of various species of coccidia of direct importance to humans are further discussed. The diversity of host potential and site selection is also mentioned, with the prediction that, hopefully, our knowledge will be much greater 15 years from now than it presently is.
A Simple, Highly Efficient Plating Method for Trypanosomatids1
Authors: TANURI AMILCAR , DE ANDRADE PAULO P. , DE ALMEIDA DARCY F.
Published: May 2007

A simple technique for plating trypanosomatids includes use of plates with lower agar concentrations than those usually prescribed for plating bacteria and a simple system to prevent dehydration due to the long incubation time needed for formation of visible colonies. Consistently high plating efficiency was thus achieved. Colonies from Herpetomonas samuelpessoai and Crithidia deanei were clearly distinguishable from each other; their individual characteristics varied with plating conditions.
Rapid In Vitro Prescreen for Chelators as Potential Trypanocides Based on Growth of Crithidia fasciculata1
Authors: SHAPIRO ANNA , HUTNER S. H. , KATZ LILLIAN , BACCHI C. J.
Published: May 2007

A rapid in vitro prescreen for Fe‐binding chelators has been developed with growth of Crithidia fasciculata and the sparing of its heme requirement in a defined medium as a test system. The prescreen functions as an index of chelator‐mediated Fe transport and as an index of growth inhibition, presumably by the interference with Fe and/or heme metabolism at intracellular chelatable sites. Of 161 chelators examined, 84 were active heme‐sparers; 32 of these inhibited growth at low chelator concentrations. Twenty‐eight other chelators inhibited growth and another 49 were inactive. Such chelating activity directed at Fe and heme targets in hemoflagellates may provide leads for chemotherapy.