bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation and Partial Characterization of Surface Membranes From Leishmania Donovani Promastigotes*
Authors: DWYER DENNIS M.
Published: May 2007

Cell surface pellicular membranes (PM) were isolated from promastigote forms of Leishmania donovani by differential and discontinuous sucrose gradient centrifugation procedures. the PM had a density equivalent of ∼ 1.19 g/cm3. As ascertained by electron microscopy, longitudinal parallel arrays of subpellicular microtubules (MT) remained attached to the isolated PM inner lamina, and this feature was used to assess membrane fraction purity. Gradient fractions having ∼ 95% of all membranes combined with MT were obtained routinely. the attached MT imparted a structural asymmetry to the PM permitting uniequivocal identification of the membrane external and cytoplasmic surfaces. the supramolecular structure of attached MT was evident in negatively stained PM. In ultrathin sections, PM had a mean width of ∼ 7.2 nm and attached MT a diameter of ∼ 29 nm. the MT were apparently cross‐bridged both to each other and to the PM via a flocculent filamentoid nexus. As determined by sodium dodecylsulfate‐polyacrylamide gel electrophoresis, isolated PM contained ∼ 40 peptide bands ranging in apparent molecular weight from ≤ 1.2 × 104 to ≥ 2.2 × 105daltons. of these, 19 were stained with periodic acid‐Schiffs’ reagent suggesting that most PM carbohydrate constituents were present as glycopeptides. A presumpative glycolipid/polysaccharide PM constituent was also identified in such gels.
Eimeria Meleagrimitis Tyzzer In Turkeys: the Life Cycle and Effects of Inoculum Size and Time On Severity of Infection and Intestinal Distribution
Authors: RUFF M. D. , DORAN D. J. , AUGUSTINE P. C.
Published: May 2007

Developmental stages of Eimeria meleagrimitis Tyzzer were found throughout the intestine and ceca of turkeys given inocula ranging from 104 to 7.5 × 105 sporulated oocysts/bird. Infection initially occurred in the duodenum and upper jejunum but later moved down the intestine and into the ceca. the speed with which the infection moved into these areas was roughly proportional to the inoculum size. Heaviest infections were in the ileum, neck of the cecum, and large intestine. the life cycle consisted of 5 asexual generations before gametogony, a 6th asexual generation developing simultaneously with gametogony. First‐ and 2nd‐generations were located along the sides of villi in the upper intestine rather than in the crypts of Lieberkühn, as previously described in England for this species. Transitory first‐generation stages that were abnormally large and usually degenerate were found in the neck of the cecum.
Attachment and Short‐Term Maintenance of Motility and Viability of Entamoeba Histolytica In A Defined Medium*
Authors: GILIN FRANCES D. , DIAMOND LOUIS S.
Published: May 2007

Organic requirements for attachment to glass, elongation, and motility of Entamoeba histolytica, have been determined. the trophozoite, which has been grown axenically only in highly complex media with reduced oxygen tensions, remains rounded and detached when placed in a Tris‐HCl buffered solution containing NaCI, KCI, MgCI2, and CaCI2. A maintenance medium in which the amebae could attach to glass, elongate, and remain motile and viable for 12 to 24 h was devised with the addition of cysteine, ascorbic acid, bovine serum albumin, and the vitamin solution of medium NCTC #107. Tris‐HCI was the most effective buffer tested and the optimal pH was 6.9 to 7.0. Survival, but not attachment, of the amebae was decreased at osmolalities ranging between 110 and 180 milliosmoles/kg, whereas both functions were decreased above ∼260 milliosmoles/kg. Bovine serum albumin, the most effective of the proteins tested, and the vitamin solution helped maintain attachment of some ameba strains, but were not required by other strains. the requirements for cysteine and ascorbic acid were absolute and highly specific. During incubation in the maintenance medium, cell volumes decreased. Sensitivity of the organisms to agglutination by concanavalin A, wheat germ agglutinin, soybean agglutinin and fucose binding protein remained unchanged.
The Role of Vitamin B12 Binding In the Uptake of the Vitamin By Euglena Gracilis
Authors: SARHAN F. , HOUDE M. , CHENEVAL J. P.
Published: May 2007

The uptake of [57Co]B13 (cyanocobalamin) by Euglena gracilis strain Z (ATCC 12716) occurred in 2 distinct phases‐an initial rapid phase followed by a slower secondary phase. This secondary phase appeared after the saturation of the binding sites involved in the initial rapid phase and was energy‐dependent and completely inhibited by 2,4‐dinitrophenot, KCN and sodium azide. the subcellular localization of labeled cyanocobalamin taken up by the cell was mostly contained in the chloroplast fraction. the time course and the saturation kinetics of B12 uptake by purified chloroplast fraction indicated that this fraction and the intact cell had a similar affinity for the vitamin B12. This suggested that the chloroplasts contained the binding sites for vitamin 12 and might regulate the uptake process in the intact cell. the kinetic properties of the overall 12 uptake mechanism suggested that the initial phase represent the binding of vitamin 12 to the available sites on the chloroplast. the secondary phase may represent the de novo synthesis of new binding sites.
Synthesis of Sterols In Herpetomonas Samuelpessoai: Influence of Growth Conditions*
Authors: FAGUNDES LUCIA JARDIM DE MORAES , ANGLUSTER JAYME , GILBERT BENJAMIN , ROITMAN ISAAC
Published: May 2007

Ergosterol was the only sterol detected in Herpetomonas samuelpessoai grown in a defined, lipid‐free medium. When cultivated in a complex medium, this flagellate was found to contain 6 additional sterols. As measured by incorporation of L‐[Me‐14C]methionine, in the absence of acetate, the sterol synthesis was greater at 28 C than at 37 C; in the presence of acetate, however, this synthesis was greater at 37 C. When [2‐14C]acetate was used as the sterol precursor, the synthesis level at 37 C exceeded that at 28 C.
Concanavalin A‐Sepharose Chromatography of Hexosaminidase Isozymes Secreted By Tetrahymena*
Authors: VICK G. WESLEY , BLUM J. J.
Published: May 2007

Tetrahymena pyriformis strain HSM secretes 4 isozymes of hexosaminidase. Purified isozymes B1 and B2 are eluted from the void volume of a concanavalin A‐Sepharose column, suggesting that they are not glycosylated. Purified isozymes A1 and A2 bind to the column and are eluted at ∼0.1 M α‐methylmannoside, suggesting that these isozymes are glycoproteins. In agreement with earlier deductions based on a differential kinetic assay for the A and B isozymes, the elution pattern of hexosaminidase activity from material secreted by cells grown to early and late stationary phase was consistent with these secretions containing primarily the B and the A isozymes, respectively.
Method for Coding Data on Protozoan Strains for Computers
Authors: DAGGETT PIERRE‐MARC , KRICHEVSKY MICAH I. , ROGOSA MORRISON , CORLISS JOHN O. , GIROLAMI JAMES P.
Published: May 2007

SYNOPSIS. Traditionally, observations on the nature of protozoa have been published in periodicals or books, or remain buried in research notebooks. The retrieval and processing of information on a particular species or strain are dependent solely upon individual investigators. Although various modern methods have been applied to the study of protozoa, no attempt has been made to develop a system with which information on protozoan strains can be stored, retrieved easily, and processed for various analyses by computer technology. Based upon an existing system for encoding data on bacterial strains, a complementary system applicable to protozoan strains was developed and is described herein.
Eimeria chihuahuaensis sp.n. and Other Coccidia from Dipodomys spp. in El Paso County, Texas
Authors: SHORT JEFFERY A. , MAYBERRY LILLIAN F. , BRISTOL JOHN R.
Published: May 2007

SYNOPSIS. Dipodomys merriami Mearns and Dipodomys ordi Woodhouse were surveyed for coccidia in El Paso County, Texas. Infections with Eimeria chobotari. Eimeria dipodomysis and Eimeria balphae were 24.8%. 4.4%, and 11%, respectively, for D. ordi. Dipodomys merriami had an infection level of 23.8% with E. chobotari. Four animals concurrently harbored E. chobotari and E. balphae or E. dipodomysis or a new species Eimeria chihuahuaensis. Male and female host infection levels were not significantly different. The new species is described and photographs of 3 previously described Eimeria from Dipodomys are presented.
Fine Structure of Zygotes and Oocysts of Eimeria nieschulzi*
Authors: SIBERT GARY J. , SPEER CLARENCE A.
Published: May 2007

SYNOPSIS. Mature macrogamonts were present in the small intestine of rats 5.5 to 7.5 days postinoculation with Eimeria nieschulzi oocysts; oocysts were present at 6 to 7.5 days. Types I and II wall‐forming bodies in macrogamonts began to undergo ultrastructural changes within zygotes to form the outer and inner layers of the oocyst wall. Before and during oocyst wall formation a total of 5 membranes (M1–5) were formed at or near the surface of the zygote. The outer and inner oocyst wall layers formed between M2 and M3, and M4 and M5, respectively. The mature oocyst was loosely surrounded by M1 and M2, had an electron‐dense outer layer, 100–275 nm thick, and an electron‐lucent inner layer, 160–180 nm thick. It also contained an electron‐lucent line consisting of M3 and M4 interposed between the outer and inner layers of the oocyst wall. The micropyle, measuring 935 × 47 nm, was located in the outer layer of the oocyst wall and consisted of 10–14 alternating layers of electron‐dense and lucent material. The sporont of mature oocysts was covered by M5, immediately beneath which were M6 and M7. The sporont contained a nucleus and nucleolus, lipid and amylopectin bodies, mitochondria, ribosomes, as well as smooth and rough endoplasmic reticulum. Canaliculi, Golgi complexes, and types I and II wall‐forming bodies were absent.
Electrical Events Correlated with Contractile Vacuole Activity in the Suctorian, Heliophrya
Authors: EAGLES DOUGLAS A. , GREGG ROBERT A. , SPOON DONALD M.
Published: May 2007

SYNOPSIS. The surface membrane potentials of suctorian genus Heliophrya were studied with intracellular electrodes. Resting membrane potentials averaged ‐32 mV, and spontaneous depolarizing potentials occurring at apparently random intervals and having a variety of waveforms were routinely observed. Such spontaneous potentials were correlated in time with visually monitored contractile vacuole activity. Individual contractile vacuoles had unique, although somewhat variable, electrical signatures. In the presence of an intracellular electrode all vacuoles contracted independently, but at approximately the same frequency. The amplitude of the electrical potentials increased when the membrane was hyperpolarized and decreased when it was depolarized. The sign of such potentials reversed at between ‐10 mV and the zero membrane potential. A 20% decrease in the membrane resistance was measured at the peak of the spontaneous depolarizing potentials.
Enrichment for Auxotrophic Mutants of Tetrahymena Using Density Gradient Centrifugation*
Authors: HEPFER CAROL ELY , KANEY ANTHONY R.
Published: May 2007

SYNOPSIS. A protocol based on density differences between starved and fed cells and employing density gradient centrifugation has been devised to facilitate the isolation of auxotrophic mutants of cell lines derived from Tetrahymena thermophila strain B1868. First, a mass phenotype screening procedure was established whereby true auxotrophic mutants and slow‐growing wild‐type cells such as strain C* could readily be distinguished. Second, simulation experiments were performed in which wild‐type cells starved first in non‐nutritive buffer, then suspended in a defined medium lacking a single essential amino acid became significantly denser than the same cells when starved, then suspended in a complete defined medium. Finally, using the same protocol, a reconstruction experiment was carried out which resulted in effective separation of wild‐type cells from cells of a tyrosine auxotroph. The overall procedure resulted in a 9‐fold increase in the relative frequency of auxotrophic cells, while the density gradient centrifugation alone provided a 400‐fold enrichment.
Tritrichomonas muris in the Hamster: Pseudocysts and the Infection of Newborn
Authors: MATTERN CARL F. T. , DANIEL WENDELL A.
Published: May 2007

SYNOPSIS. Female golden hamsters, either in the last week of pregnancy or in the first weeks of nursing, excreted in their feces variable numbers of pseudocysts of Tritrichomonas muris. Pseudocysts examined by electron microscopy had internalization of the 3 anterior flagella and the undulating membrane with its recurrent flagellum. The undulating membrane and the associated marginal lamellae were characteristic of T. muris. Pseudocysts gradually become motile after 2 or more hours of incubation in medium. The “excysted” trophozoites were identified ultrastructurally as T. muris. Newborn hamsters were not infected with T. muris at 3 days of age, but by the 7th day essentially all were found to have infected ceca, concomitant with cecal enlargement and the appearance of adult‐type feces.
Trypanosoma cruzi: Correlation of Growth Kinetics to Zymodeme Type in Clones Derived from Various Sources*†
Authors: DVORAK JAMES A. , HARTMAN DEBORAH L. , MILES MICHAEL A.
Published: May 2007

SYNOPSIS. Trypanosoma (Schizotrypanum) cruzi clones were derived from isolates of an acute human case of Chagas' disease (strain Esmereldo), a human case of T. cruzi infection (strain CAN‐III) and from a naturally infected opossum (strain WA‐250). The isoenzyme patterns and growth rates of the clones were stable during long‐term cultivation, by serial passages, of the parasites in liquid medium. Both clones of strain Esmereldo were zymodeme II; the 2 clones of strain CAN‐III, zymodeme III; and the 5 clones of strain WA‐250, zymodeme I. The range in doubling times of the parasite populations in liquid medium were 36–49. 7 h (strain WA‐250), 117.2–133.7 h (Esmereldo clones) and 169–208 h (CAN‐III clones).
Role of Glycerol Permeation in the Bloodstream Form of Trypanosoma brucei*
Authors: GRUENBERG JEAN , SCHWENDIMANN BERNARD , SHARMA PUKH RAJ , DESHUSSES JACQUES
Published: May 2007

SYNOPSIS. Under aerobic conditions, we have determined glycerol uptake in the long slender (LS) bloodstream form of Trypanosoma (Trypanozoon) brucei brucei by studying glycerophosphate accumulation in the parasites. The coupled enzyme theory applies to the permeation‐phosphorylation sequence. Glycerol passage through the plasma membrane is asymmetric, the efflux process being favored over the influx process. No free diffusion of glycerol can be detected even under conditions under which free glycerol accumulates within the cells; most probably, glycerol permeation is mediated by a specific transport system. In the absence of respiratory activities, glycerol is known to be an end‐product of T. brucei glycolysis; its production from glycerophosphate should allow ATP synthesis. The observed efflux of free glycerol following intracellular accumulation of glycerophosphate confirms the hypothesis that glycerol production occurs through reversal of glycerol kinase activity.

We conclude that in vivo the role of the carrier‐mediated asymmetric permeation process is to prevent inhibition of the reversal of the glycerol kinase‐mediated reaction by removing free glycerol.
Electron Microprobe Analysis of Zinc Incorporation into Rumen Protozoa
Authors: BONHOMME A. , QUINTANA C. , DURAND M.
Published: May 2007

SYNOPSIS. With the aid of electron microprobe analysis on ciliate spreads, we detected zinc in ciliates and its accumulation in the endoplasm. A correlation was found between the amount of zinc accumulation and its concentration in the medium. By the same microprobe analysis of ultrathin sections, we determined semiquantitatively the zinc accumulation in the intracytoplasmic granules and its presence in macronuclei and in intra‐ and extracellular bacteria.
Thymidylate Synthetase as a Chemotherapeutic Target in the Treatment of Avian Coccidiosis*
Authors: COLES ANTHONY M. , SWOBODA BENNETT E. P. , RYLEY JOHN F.
Published: May 2007

SYNOPSIS. Thymidylate synthetase (E.C.2.1.1.45) has been demonstrated in unsporulated oocysts of Eimeria tenella. The properties of this enzyme have also been investigated in Tetrahymena pyriformis, as a protozoan model, and 7‐day‐old chick embryo, as a host model. The enzymes from E. tenella and chick embryo were inhibited by all concentrations of MnCl2 and MgCl2 tested. Tetrahymena pyriformis thymidylate synthetase was stimulated by low concentrations of both these cations but was inhibited by high concentrations. Subsequent data refer to chick embryo, E. tenella and T. pyriformis respectively: the apparent Km was 5.89 μM, 5.94 μM, and 0.53 M for the substrate dUMP: and 5.13 μM, 1.10 μM and 4.65 μM, respectively for the cofactor N5N10‐methylenetetrahydrofolate. The pH optimum for the enzyme from both chick embryo and T. pyriformis was 8.0, with Tris‐HCl buffer; activity of E. tenella thymidylate synthetase was still increasing at pH 8.2. The E. tenella enzyme was found to have a molecular weight of 4.6–4.9 × 105 daltons. The effects of nucleotides, inhibitors, and the omission of assay components on each enzyme are presented. Thymidylate synthetase from E. tenella is not greatly different from that of chick embryo, but does not resemble the enzyme from T. pyriformis. A case for using thymidylate synthetase as a chemotherapeutic target in the treatment of Eimeria infections remains. Indeed Eimeria may be considered as a model for infections caused by other protozoan parasites, such as Toxoplasma and Plasmodium, provided that suitable inhibitors can be found that are not toxic to the host.
The Chemotherapy of Protozoal Infections of Veterinary Importance1
Authors: JOYNER L. P.
Published: May 2007

The use of drugs in domestic animals is dominated by considerations of cost‐effectiveness and profitability. They are extensively used against coccidial infections of poultry where they are an important factor in intensive husbandry. Ionophore antibiotics, which dominate this field, may have applications in ruminants. Imidocarb is of therapeutic and prophylactic value against babesial infections and there are new prospects for control of theileriasis. Effective drugs for the control of African trypanosomiasis are limited and attention is being given to alternative uses of available compounds.
The Chemotherapy of Protozoal Infections: Whither?1
Authors: STECK EDGAR A.
Published: May 2007

An assessment is given of the present state of the art in chemotherapy of protozoal infections with suggestions as to improved results in the future, especially by rendering available drugs more effective. Selective targeting of chemotherapeutic agents through enhancement of lysosomotropic character has been demonstrated, particularly through the use of liposome‐encapsulated drugs.
A Study of Choanoflagellates (Acanthoecidae) from the Weddell Sea, Including a Description of Diaphanoeca multiannulata n. sp.1
Authors: BUCK KURT
Published: May 2007

Eight species of loricate choanoflagellates (Acanthoecidae), Acanthoecopsis spiculifera Norris, Bicosta antennigera Moestrup, Bicosta spinifera Throndsen, Calliacantha multispina Manton & Oates, Calliacantha simplex Manton & Oates, Crinolina aperta Leadbeater, Diaphanoeca multiannulata n. sp., and Parvicorbicula socialis (Meunier) Deflandre, have been observed, by light and electron microscopy, in samples obtained from the Weddell Sea during the austral summer of 1977. Diaphanoeca multiannulata is described for the first time from these samples: the other organisms are discussed. The distribution of most species within the Weddell Sea was widespread. Habitats in which choanoflagellates were found included the water column, the edge of (or ponds on) ice floes, and the interior of ice floes. The distributional, environmental, habitat, and/or morphological range of all previously described species is expanded. Methods of variation of transverse costal diameters between genera may be potentially useful to the understanding of taxonomy and phylogeny of this family.
Bottled Mineral Waters Polluted by Protozoa in Mexico
Authors: RIVERA FERMÍN , GALVÁN MATILDE , ROBLES ESPERANZA , LEAL PILAR , GONZÁLEZ LETICIA , LACY ANA MARÍA
Published: May 2007

A survey of protozoa polluting bottled mineral water in Mexico was carried out using samples obtained from the three best‐selling brands of bottled mineral water in the country. The organisms were concentrated through filtration procedures and subsequently cultured in sterile media. The cultures were observed over four weeks, with identification to the level of genus and species. Most commonly found were the amoebae Naegleria gruberi, Acanthamoeba astronyxis, and Vahlkampfia vahlkampfi (trophic as well as cystic stages) plus one flagellate, Bodomorpha minima. No ciliates were detected. The public health importance of the findings is obvious, since some strains of Naegleria and Acanthamoeba have the potential to cause human disease that may lead to death.
Life Cycle of Eimeria christenseni Levine, Ivens & Fritz, 1962 from the Domestic Goat, Capra hircus L.1
Authors: LIMA JOSÉ D.
Published: May 2007

The endogenous development of Eimeria christenseni was studied in 10 two‐ to four‐week‐old kids inoculated with 106‐107 sporulated oocysts. They were killed at intervals from two to 26 days after inoculation, and their tissues were examined for endogenous stages of the coccidian by light microscopy. Such stages were found in the small intestine and mesenteric lymph nodes. In the sexual cycle, two generations of meronts were found. The first generation developed in endothelial cells of lacteals in the jejunun and ileum and mesenteric lymph nodes, and mature meronts were first seen 14 days after inoculation. The second generation developed in epithelial cells of the glands of Lieberkuehn in the jejunum and ileum and in mesenteric lymph nodes, and its mature meronts were first seen by 16 days. Sexual stages were present mostly in epithelial cells of the tips and sides of the villi and less frequently in crypt cells of the jejunum and ileum. Mature macrogametes and microgamonts and oocysts were also first seen by 16 days. The prepatent period was 17 (14‐23) days; the patent ranged from 8 to more than 30 days. Sporulation time was 3‐4 days at 30°C. E. christenseni was found to be pathogenic, kids inoculated with 1‐5 × 105 sporulated oocysts exhibited the following signs: severe diarrhea, anorexia, polydipsia, poor hair coat, and extreme weakness. They recovered about a month later, but their growth rates appeared to be lower than those of uninoculated animals kept under the same conditions. One kid died 20 days after inoculation with 107 oocysts.
Three New “Biological” Species of Tetrahymena (T. hegewischi n. sp., T. sonneborni n. sp., T. nipissingi n. sp.) and Temperature Tolerance of Members of the “pyriformis” Complex1
Authors: NYBERG DENNIS
Published: May 2007

Stocks of the Tetrahymena pyriformis complex have been collected in North America and their mating reactivity has been studied. In addition to stocks mating with Tetrahymena americanis, T. borealis, T. pigmentosa, T. hyperangularis, and T. australis, stocks belonging to old syngen 5 and three new mating groups, numbers 13, 14, and 15, were discovered. Syngen 5 and groups 13 and 14 are distinct “biological” species, based on their reproductive isolation from other groups and on the ability of withingroup crosses to produce immature progeny. These species have been named T. hegewischi n. sp., T. sonneborni n. sp., and T. nipissingi n. sp., respectively. The cross between the two group 15 stocks did not produce immature progeny, and there is not sufficient evidence to conclude that this pair of stocks represents a separate species. Temperature tolerance measurements have been made on stocks representing all known micronucleate members of “pyriformis” complex. Within each species, the range of temperature tolerances is narrow; the average within‐species standard deviation is 0.63°C. The species averages range from 32.7 to 40.7°C. Using syngen numbers, the order from lowest to highest temperature tolerance is 9, 8, 10, 7, 6, 4, 13, 14, 12, 11, 5, 3, 2, 1. The large differences among species make temperature tolerance a useful aid in identification, but the origins of the differences among species are unknown.
An Ultrastructural Study of Phytomonas davidi Lafont (Trypanosomatidae)1
Authors: POSTELL FRED J. , McGHEE R. BARCLAY
Published: May 2007

Phytomonas davidi (Trypanosomatidae) possesses typical trypanosomatid organelles: subpellicular microtubules, kinetoplast‐mitochondrial complex, K‐DNA, and four subflagellar pocket microtubules. A greater concentration of subpellicular microtubules was observed in the latex forms than in those found in the salivary glands of its insect vector. Only in the latex flagellates (the stage with postnuclear torsion) were subpellicular microtubules interconnected by crossbridges observed. Morphology and development of mitochondrial aristae varied according to the source of the flagellates. Organisms taken from culture medium had extensively developed plate‐like cristae; sparse tubular cristae were observed in the latex forms; and highly developed tubular cristae were seen in flagellates from the lumen of the vector's salivary glands, though organisms in the salivary gland channels had few or none.
Ultrastructure of the Somatic Cortex of the Gymnostome Ciliate Spathidium spathula (O. F. M.)1
Authors: WILLIAMS DONALD B. , WILLIAMS BENJAMIN D. , HOGAN B. K.
Published: May 2007

The somatic cortex of Spathidium spathula is described ultrastructurally. The pellicle consists of an outer membrane and an underlying alveolar system. Numerous membrane‐bound mucocysts and spherical electron‐opaque bodies have similar circular sites of attachment to the outer membrane. Below these are a microfibrillar zone and an underlying region of rough ER. Mitochondria are lined up under the rough ER in longitudinal cortical ridges. Parasomal sacs are found near the basal bodies and are associated with cytoplasmic membranous sacs. Various microtubular and fiber systems are associated with single basal bodies: (1) a short kinetodesmal fiber; (2) two transverse microtubular ribbons and a transverse fiber; (3) a postciliary microtubular ribbon, initially sandwiched by two fibers, which gives rise to longitudinal subpellicular microtubules extending posteriorly for a distance of some four or five basal bodies; and (4) a system of overlapping subkinetal microtubules. A three‐dimensional reconstruction is included. The somatic cortex of S spathula is similar to that reported for other Haptorida of the ciliate subclass Gymnostomata.
Determination of Macronuclear Fragmentation, Stabilization of Cell Union, and Cessation of Feeding Activity in Triplet Conjugants of Paramecium1
Authors: TAKAGI YOSHIOMI , YOSHIKI YUKO , BABA CHISAKO , YAMADA SEIJI
Published: May 2007

Triplet conjugants of Paramecium multimicronucleatum, in each of which the third cell unites by its anterior and to a posterior part of one of the conjugating pair, are induced by conjugation inducing chemicals, KCl and acriflavine in a Ca11‐poor condition. If the triplets are prematurely transferred to medium free of such chemicals, the third cells usually separate and no macronuclear fragmentation occurs in them. But in third cells of long lasting triplets, macromuclear fragmentation regularly begings at ∼12 In after chemical treatment Staluhzaton of cell union and determmation of macronuclear fragmentation occured between ∼100 and ∼130 min after initiation of chemical treatment. Electron‐microscopic observation of the stabilized third cell revealed that the two cell membranes at the uniting region were partially fused to form cytoplasmic bridges. Chemically treated cells began to cases feeding before the cell union and fully ceased such activity at ∼130 min after the treatment.
Virulent and Avirulent Strains of Babesia bovis: The Relationship Between Parasite Protease Content and Pathophysiological Effect of the Strain
Authors: WRIGHT I. G. , GOODGER B. V. , MAHONEY D. F.
Published: May 2007

A virulent strain of Babesia bovis (“L” strain) was rendered avirulent by irradiation with 35 krads with a γ source. Another virulent strain of B. bovis (“C” strain) was made avirulent by rapid blood passage through 12 splenectomised calves. Both the parent virulent and their respective avirulent strains were injected into susceptible cattle. A nonfatal disease was observed in those intact cattle that had avirulent parasites; however, a fatal disease was produced in those animals that had received virulent parasites and in splenectomised calves that had received avirulent parasites. Blood kinin levels rose and plasma kininogen levels fell significantly in those animals infected with both virulent strains. Nonsignificant changes occurred with these parameters in animals infected with avirulent parasites. Preparations of disrupted parasites were obtained from the four parasite populations. Both virulent strains contained high levels of protease. The avirulent forms contained insignificant amounts. As parasite doubling times and maximum parasitaemias were the same for all four parasite populations, we conclude that these enzymes are not obligatory for parasite multiplication in the vertebrate host. Their role in producing pathological changes in the host is discussed.
Isolation of a Stearoyl CoA Desaturase from Tetrahymena thermophila
Authors: BERTRAM JON , ERWIN J. A.
Published: May 2007

Cell free preparations of Tetrahymena thermophila contain an enzyme that catalyzes the direct desaturation of stearoyl CoA to octadecenoic acid. The enzyme is associated with the microsomal fraction of the ciliate. Substrate for the enzyme consists of either free stearic acid or stearoyl CoA. Both ATP and CoA are required when free stearate is the substrate and are also highly stimulatory when stearoyl CoA is the substrate. With stearoyl CoA as the substrate, either NADH or NADPH are required for desaturase activity. In the presence of ATP and CoA, either NAD or NADP can replace NADH and NADPH. Desaturase activity is optimal when the enzyme is incubated at a pH of 7.2 and a temperature of 30–35°C. Highest levels of the stearoyl CoA desaturase are found in stationary phase ciliates grown at 35°C.
Determination of Maximal Growth Rate Using Continuous Culture1
Authors: YEE JOHN , BROEKHOVEN LOUIS , COLGAN PATRICK , HARMSEN RUDOLF
Published: May 2007

Study of microorganism growth kinetics requires measurement of maximal specific growth rate. Standard methods of measurement‐batch, semicontinuous and continuous steady state‐have sources of imprecision that can be substantially reduced by a modification of the continuous steady‐state method. Data are presented, using the ciliate Tetrahymena pyriformis, that indicate that the theoretical foundation of the new method is firm and that precision can be increased.
Variation of DNA Levels in Euglena Related to pH of Culture Medium1
Authors: COOK J. R.
Published: May 2007

Variations in DNA levels for log‐phase Euglena have been shown to be directly related to the pH of the culture medium. Data are presented here for cultures grown in Cramer and Myer's medium at pH 3.0 and 6.8. DNA levels are ∼50% greater for Euglena at the higher pH value, confirming earlier reports.
Phosphate Incorporation by Euglena gracilis During pH‐dependent Photo‐inhibition1
Authors: COOK J. R.
Published: May 2007

Inhibition of cell division in Euglena gracilis by visible light is pH‐dependent, being most severe in the pH range 3.5–5.0. Transfer of phototrophic cells from pH 6.8 to pH 4.2 can lead to cell death at modest light intensities (500 ft‐cd) and inhibition of division at lower intensities (300 ft‐cd). Inhibition is preceded by a large influx of phosphate, most of which remains in the cold PCA pool. It is suggested that light may act to reduce control over phosphate entry at these intermediate pH levels, and excess phosphate leads to inhibition of cell division or death.
Cell Cycle‐associated Changes of Guanylate Cyclase Activity in Synchronized Tetrahymena: a Possible Involvement of Calmodulin in its Regulation1
Authors: KUDO SHUZO , NAGAO SEIJI , KASAI REIKO , NOZAWA YOSHINORI
Published: May 2007

Guanylate cyclase activity decreased during the division phase of heat‐shock synchronized Tetrahymena pyriformis, strain GL. However, when Ca2+ was removed by EGTA to negate the effects of the Ca2+‐binding protein (calmodulin), which is required for the full activity of guanylate cyclase in this organism, no significant change in the enzymatic activity was observed throughout the cell cycle. On the other hand, the reduced guanylate cyclase activity at division phase was associated with a decreased level of calmodulin content. These results suggest that fluctuations in guanylate cyclase activity during the cell cycle would be dependent on the concentration of calmodulin.
Effect of Holothurin on Trypanosoma musculi infection in Three Strains of Mice1
Authors: SEN DILIP K. , LANKARANIFARD GHOLAMREZA , NARAIN NAND K.
Published: May 2007

The effect of holothurin (a marine biotoxin) on the resistance of mice to Trypanosoma musculi was measured by studying changes in the parasite population in vivo. Swiss Webster (SW), Beige (BG), and Black (BL) mice treated with holothurin prior to and simultaneously with infection of trypanosomes had lower parasitemias than controls. Higher levels of parasitemia were observed in mice treated after infection with trypanosomes. The timing of administration of holothurin appeared to be an important factor in the observed effect. The minor variations in the parasitemia seemed to be related to the mouse strain.
Contamination Expérimentale In Vivo et In Vitro par Aggregata eberthi: Etude Ultrastructurale1
Authors: PORCHET ELIANE , RICHARD ALAIN , FERREIRA ELISABETH
Published: May 2007

RESUME

Le mode de contamination par Aggregata a étéétudié expérimentalement in vivo chez le Crabe, in vitro sur cultures cellulaires de Mollusques, puis suivi en microscopie électronique. Quelques heures après le repas infestant, les spores s'ouvrent dans l'estomac du Crabe et les sporozoïtes gagnent l'intestin moyen. Là ils traversent l'épithélium dans les espaces intercellulaires. La perforation de l'epaisse basale est liée à l'apparition d'une substance dense, de nature probablement enzymatique. Les lésions causées aux tissus du Crabe sont minimes. Les mérozoïtes sont capables de pénétrer en culture dans des cellules provenant de divers Mollusques; la membrane de la cellule‐hǒte n'est pas rompue. Un debut de développement est observé avec l'apparition d'un nucléole dans le noyau.
Host and Site Specificity in the Coccidia: a Perspective1
Authors: MARQUARDT WILLIAM C.
Published: May 2007

Some generalizations of a decade ago are reexamined in light of modern advances in coccidiology. Perhaps surprisingly, not many modifications need or can yet be made. Future successes of significance will be in areas of immunology and chemical genetics.
The Coccidian Caryospora bubonis in the Great Horned Owl (Bubo virginianus)1
Authors: STOCKDALE P. H. G. , CAWTHORN R. J.
Published: May 2007

The life cycle of Caryospora bubonis was studied in the Great Horned Owl. Owls fed sporulated oocysts became patent on days 8–13, and peak oocyst production occurred between days 14 and 18. Owls fed infected mice became patent on days 8–10, and peak oocyst production occurred between days 9 and 13. The reduction in length of the life cycle in owls fed infected mice provides evidence that both indirect and direct life cycles can occur in this species and suggests that parallels exist in the lives of various isosporid, eimeriid, and other coccidia that may not have been sufficiently appreciated in the past.
The Challenge of Fish Coccidia1
Authors: DESSER SHERWIN S.
Published: May 2007

Species of Eimeria occurring in fishes show important differences, especially in their life cycles, with respect to what is known for those forms found in mammals or other hosts. In some cases, at least, some small invertebrate may play the role of vector or intermediate host. Present studies of fish coccidia may throw light on the possible evolution of certain aspects of host‐parasite interrelationships involving eimerian species in particular: for example, the earliest site (perhaps not the gut) of infection and even the “original” host group (perhaps invertebrates rather than vertebrates).
Ultrastructure of the Flagellar Apparatus and Attachment of Herpetomonas ampelophilae in the Gut and Malpighian Tubules of Drosophila melanogaster1
Authors: ROWTON EDGAR D. , LUSHBAUGH WILLIAM B. , McGHEE R. BARCLAY
Published: May 2007

Electron microscopy was used to examine the flagellar apparatus of Herpetomonas ampelophilae from the gut and malpighian tubules of Drosophila melanogaster. The flagellates attach to the microvilli either by weaving their flagella between the microvilli or by engulfing several microvilli with an external flagellar membrane. The first type predominated in the gut while the second type was limited to the malpighian tubules. Desmosomes were not involved in either type of attachment. A subpellicular collar with emerging microtubules was found to be adjacent to the desmosome of the flagellar pocket of herpetomonads in the gut.
An Ultrastructural Study of Eimeria iroquoina Molnar & Fernando, 1974 in Experimentally Infected Fathead Minnows (Pimephales promelas, Cyprinidae) 3. Merogony1
Authors: PATERSON W. BROCKLEY , DESSER SHERWIN S.
Published: May 2007

Fathead minnows, Pimephales promelas, raised from eggs in the laboratory, were experimentally infected with oocysts of Eimeria iroquoina from either P. promelas or the common shiner, Notropis cornutus. Within intestinal epithelial cells, trophozoites thought to be derived from the sporozoites contained a prominent electron‐dense refractile body. Merozoites dedifferentiated into trophic forms by losing components of their apical complex and pellicle. The inner membrane components of the pellicle appeared discontinuous, and the micronemes became enclosed within vacuoles. Prior to merozoite formation, multinucleate meronts were limited by a single membrane. Golgi complexes were associated with the nuclei of this stage. Merozoites were formed by ectomerogony in one generation and by endomerogony in the final generation. In both forms of merogony the final nuclear division was coupled with the onset of differentiation of the merozoites and featured eccentric mitotic spindles associated with centrocones located within the nuclear envelope and with the precursors of the apical complex. A Golgi complex was closely associated with the nucleus and apical tip of the forming merozoite. Unlike other Eimeria species, the complete pellicle of the merozoites of the final asexual generation of E. iroquoina was formed within the cytoplasm of the meront, without association with the limiting membrane, thus, all pellicular components are synthesized de novo. The inner membranes of the pellicle initially appeared as longitudinal strips, each of which was associated with a pair of the 22–24 subpellicular microtubules. Mature meronts of the final asexual generation averaged 9 μm in diameter and produced 13–16 merozoites. With the exception of the internal completion of the pellicle of the final generation merozoites, the basic processes of merogony in fish Eimeria species are similar to those recorded in terrestrial hosts.
Ultrastructural Damage by Cadmium in a Marine Dinoflagellate, Prorocentrum micans1
Authors: SOYER MARIE‐ODILE , PREVOT PAUL
Published: May 2007

Prorocentrum micans Ehrenberg, a free‐living marine dinoflagellate, was used to test the intracellular toxic action of cadmium. The cells were cultivated in Erdschreiber medium, with Cd concentrations of 10–100 ppb. Thin sections of treated cells, examined ultramicroscopically, exhibited vacuolations, increased numbers of lysosomes, and severe mitochondrial damage. The first two alterations are a general response to toxicity; the third is Cd specific. Although some chloroplasts were affected by Cd, they were not very sensitive to its action. The nuclear apparatus was not morphologically affected.
Transmission and Scanning Electron Microscopic Studies of the Micronemata of Trypanosoma gambiense1
Authors: ITO YOSHIHIRO , FURUYA MASATO , OKA MIKIO , OSAKI HUMIO , AIKAWA MASAMICHI
Published: May 2007

The structure of micronemata arising from the surface of the bloodstream form of Trypanosoma gambiense was studied by electron microscopy. In order to produce micronemata, trypanosomes were incubated in either 1) phosphate buffered saline supplemented with glucose (PBSG), 2) immune mouse serum or 3) PBSG after passage through a DEAE‐cellulose column. Electron microscopic examination of the parasite revealed the presence of thread‐like micronemata arising from the anterior end and from the flagellar pocket regardless of the incubation conditions. Negative staining revealed a distinct peripheral fringe layer with nodular protrusions covering the entire surface of the micronema. The distribution and number of intramembrane particles (IMP) on the P and E faces of the micronema were similar to those of the flagellum of T. gambiense, indicating a close relationship between the membrane structure of the micronema and the flagellum. Micronemata became fragmented and adhered to each other after incubation of the parasite in the media for 12 h. Since micronemata tend to have the characteristics of adhesiveness and fragmentation, fragments of these structures might adhere to various host organs. Dispersal of potential antigenic material might be responsible, in part, for the induction of the host immune response.
In Vivo Incorporation of a Polyunsaturated Fatty Acid into the sn‐C‐1 and sn‐C‐2 Positions of Tetrahymena Glycerophospholipids1
Authors: SCHICK BARBARA P. , CONNER ROBERT L.
Published: May 2007

The glycerophospholipids of the protozoon Tetrahymena pyriformis W are unique in that the polyunsaturated fatty acid γ‐linolenate (18:3Δ6,9,12) is a major component of both the sn‐C‐1 and sn‐C‐2 positions. Tetrahymena were incubated with [1‐14C]γ‐linolenate. The positional distribution of the radiolabeled fatty acid in the three major glycerophospholipids was determined. [1‐14C]γ‐linolenate was found at both carbons of the three lipids, in general agreement with the mass distribution of γ‐linolenate, except for markedly greater labeling at the sn‐C‐2 position of phosphatidylcholine. We hypothesize that an acyltransferase exists in Tetrahymena that can esterify γ‐linolenate at both carbons during glycerophospholipid biosynthesis.
Motion of the Longitudinal Flagellum in Ceratium tripos (Dinoflagellida): A Retractile Flagellar Motion1
Authors: MARUYAMA TADASHI
Published: May 2007

The longitudinal flagellum of Ceratium tripos moves in two dissimilar ways: undulation and retraction. The undulatory wave is planar and has a wavelength of 74.3 ± 9.6 μm and an amplitude of 14.2 ± 2.3 μm in sea water. The beat frequency is 30 Hz at 20°C, pH 8.0. The retractile motion is unique to Ceratium and is triggered by mechanical stimulation on the cell body, especially at the tip of the apical horn. When it retracts, the longitudinal flagellum folds every 4–5 μm along the flagellum. Cinematographic study showed that the flagellum folded from tip to base and was finally installed into the sulcus, a groove on the ventral side of the cell. This motion is completed in sea water within 28 msec. The retracted flagellum then re‐extends and restores the undulation within a few seconds. The flagellum unfolds in the proximal portion first, then the distal, and finally the middle portion. Fixation always triggers the retraction. Scanning electron microscopy showed that the flagellum is folded and secondarily twisted in a helix. A new fiber in addition to the flagellar axoneme was found in the retracted flagellum by phase microscopy. This fiber (R‐fiber) seems to contract during the retraction to fold the flagellum.
Diffusion Coefficient of Paramecium as a Function of Temperature1
Authors: KAWAKUBO T. , TSUCHIYA Y.
Published: May 2007

The motion of Paramecium caudatum has been investigated at various temperatures by measuring the transient behavior of spatial distribution in the diffusion process of organisms that, by electric stimulus, are initially gathered at a single place in the glass culture cell. The spatial distribution through the course of diffusion has a nearly Gaussian profile. Dispersion was obtained at 1 sec intervals and increased linearly with time. The time dependence of the dispersion gave a diffusion coefficient for the random motion of the organisms. The results show that the diffusion coefficient has a maximum at the temperature at which the paramecia were cultivated.
Phagocytosis of Trypanosoma cruzi by Human Polymorphonuclear Leukocytes1
Authors: RIMOLDI MARÍA TERESA , OLABUENAGA SUSANA E. , DE BRACCO MARÍA M. DE E.
Published: May 2007

Phagocytosis of culture forms of Trypanosoma cruzi was assayed by a radioisotopic method. Purified polymorphonuclear leukocytes (PMN) were mixed with 3H‐uridine‐labeled T. cruzi epimastigotes in the presence or absence of anti‐T. cruzi antibodies. The reaction was stopped by adding N‐ethyl‐maleimide, and noningested parasites were lysed by complement. The percentage of radioactivity incorporated into the PMN pellet was recorded. The phagocytosis reaction was rapid, yielding maximum incorporation at 30 min at which point the radioactivity associated with the PMN cells decreased through release of the isotope to the supernatant. The degree of incorporation of radio‐labeled parasites was a function of the effector/target cell ratio and the antibody concentration. The method is suitable for the quantitative determination of phagocytosis of T. cruzi by normal PMN.
New Species of Lankesteria (Apicomplexa, Eugregarinida) from Ascidians on the Central California Coast1
Authors: LEVINE NORMAN D.
Published: May 2007

The following species of the gregarine genus Lankesteria were found in a study of ascidians from Monterey Bay, on the central California coast of the Pacific Ocean: L. abbotti n. sp. in Clavelina huntsmani, L. aplidii n. sp. in Aplidium solidum, L. ascidiae in Ciona intestinalis, L. diaphanis n. sp. in Archidistoma diaphanes, L. euherdmaniae n. sp. in Euherdmania claviformis, L. montereyensis n. sp. in Archidistoma molle, L. pescaderoensis n. sp. in Ritterella rubra, L. pittendrighi n. sp. in Ascidia ceratodes, L. psammii n. sp. in Archidistoma psammion, L. ritterellae n. sp. in Ritterella pulchra, L. ritterii n. sp. in Archidistoma ritteri, L. synoici n. sp. in Synoicum parfustis, and Lankesteria sp. in Botrylloides sp. No gregarines were seen in the following ascidians: Aplidium californicum, A. propinquum, Botryllus tuberatus, Diplosoma macdonaldi, Perophora annectens, and Polyclinum planum.