bluuebunny/crossref_metadata_2025 huggingface dataset:
Restriction Enzyme Analysis of Mitochondrial DNA of Acanthamoeba Strains in Japan
Authors: YAGITA KENJI , ENDO TAKURO
Published: May 2007

ABSTRACT. Eight isolates, identified as either Acanthamoeba castellanii or A. polyphaga from human eye infections, contact lens containers, and soil in Japan, were characterized by restriction fragment length polymorphisms (RFLP) of mitochondrial DNA (mtDNA). Mitochondrial DNA was digested with either Bgl II, EcoR I, Hind III, Hpa I, Sca I or Xba I, electrophoresed in agarose gels, and stained with ethidium bromide. Four distinct RFLP phenotypes that refer to the collection of six fragment size patterns obtained for a single strain with six enzymes, were discovered among the eight strains used in this study. Three strains morphologically classified as A. polyphaga share a single RFLP phenotype with the Ma strain of A. castellanii. The interspecific sequence differences of 7.06–12.74% in DNA nucleotide were estimated from the proportion of DNA fragments shared by each pair of mtDNA.
Distribution of Carbohydrates Recognized by the Lectins Euonymus europaeus and Concanavalin A in Monoxenic and Heteroxenic Trypanosomatids
Authors: GAZZINELLI RICARDO T. , ROMANHA ALVARO J. , FONTES GILBERTO , CHIARI EGLER , GAZZINELLI GIOVANNI , BRENER ZIGMAN
Published: May 2007

We observed a wide distribution of the carbohydrate epitopes galactosylα(1–3) galactose (galα1–3 gal), α‐glucoside, and α‐mannoside in mono‐ and heteroxenic trypanosomatids by using fluorescein‐labelled lectins of Euonymus europaeus (EE) and Concanavalin A (Con A) as well as sera from acute chagasic patients who have very high levels of anti‐galα(1–3) gal antibodies. The direct fluorescence test for galα1–3 gal with EE was positive at minimum concentrations of 6 μg/ml for heteroxenic trypanosomatids and 0.7 μg/ml for monoxenic ones and for the plant parasite, Phytomonas. On the other hand, heteroxenic trypanosomatids that infect vertebrates bound ten‐fold more Con A than monoxenic flagellates and Phytomonas. These data were confirmed in ELISA and Western Blot assays carried out with peroxidase‐labelled EE and Con A. Euonymus europaeus recognized several glycoproteins in all trypanosomatids that we tested. Con A, however, recognized a glycoprotein cluster in heteroxenic protozoa, which ranging from 60–120 kDa, seemed to lack monoxenic parasites and Phytomonas. These findings suggest that α‐D‐mannose and α‐D‐glucose might play an important role in the interaction between trypanosomatids and vertebrate hosts.
Trypanosoma cruzi: Flow Cytometric Analysis of Developmental Stage Differences in DNA
Authors: NOZAKI TOMOYOSHI , DVORAK JAMES A.
Published: May 2007

Flow cytometry and DNA binding‐specific fluorescent reagents were used to compare the total DNA, G‐C, and A‐T content of the epimastigote and trypomastigote stages of Trypanosoma cruzi stocks. Significant total DNA differences of 2–12% between epimastigotes and trypomastigotes were found in three of six stocks studied. The epimastigote G‐C content of five of six stocks was 4–8% higher than trypomastigotes, whereas the trypomastigote A‐T content was 2.5–13% higher than the epimastigote A‐T content. Although no obvious developmental stage association between total DNA and base composition was found, intrastage associations do exist. These observations were unaffected by nucleoprotein extraction implying that the observed differences between trypomastigotes and epimastigotes are not a consequence of nucleoprotein interference with DNA‐binding fluorochromes. The nuclei and kinetoplasts of four T. cruzi stocks were isolated and analyzed. Developmental stage differences in nuclear and kinetoplast DNA are stock‐dependent and base composition‐dependent; both organelles contribute to the observed differences in DNA of intact cells. We found a nearly linear association between the percentage of total kinetoplast DNA, G‐C, and A‐T content. During metacyclogenesis, the G‐C content decreases by approximately 7% as epimastigotes transform into metacyclic trypomastigotes. The decrease in G‐C content precedes changes in morphology or in complement resistance. If the DNA changes are causally connected to developmental stage transformations in T. cruzi remains to be determined. However, our results could facilitate studies of the molecular genetic processes the parasite uses to successfully complete various phases of its life cycle and, consequently, the disease process it evokes.
Symposium Introductory Remarks: A Brief History of Aquatic Microbial Ecology
Authors: GRAHAM JAMES M.
Published: May 2007

ABSTRACT This report serves to introduce the symposium on food chains and food webs that is jointly sponsored by the Society of Protozoologists and the Phycological Society of America. A brief history of the field of aquatic microbial ecology is presented with an emphasis on the development of theoretical models that have directed the course of research — research that has shaped the development of new and more complex models of the present. the paper aims to provide historical background for all symposium participants and an introduction to the specific presentations of the four guest speakers.
Sphaerospora epinepheli N. Sp. (Myxosporea: Sphaerosporidae) Observed in Grouper (Epinephelus malabaricus)
Authors: SUPAMATTAYA K. , FISCHER‐SCHERL T. , HOFFMANN R. W. , BOONYARATPALIN S.
Published: May 2007

Sphaerospora epinepheli n. sp. is described from grouper, Epinephelus malabaricus, in cage‐cultured and wild fish collected from both coastal lines of southern Thailand. Subspherical to spherical spores and mono‐ or disporous pseudoplasmodia were observed in the lumen of kidney tubules. Pseudoplasmodia were round to elongate, size range 15.6–22.9 μm (length) × 8.4–21.6 μm (width). Spores were 7.8–10.0 μm (length) × 12.3–14.5 μm (thickness), and 7.0–9.5 μm (width) with two spherical polar capsules of equal size measuring 2.9–4.4 μm in diameter and containing polar filaments with six or seven windings. Two uninucleate sporoplasms showed iodine vacuoles. Blood stages, similar to C‐blood protozoans observed from freshwater fish in Europe, were found from peripheral blood smears of grouper. Ultrastructural studies of blood stages showed a similar structure to unidentified mobile protozoans from the blood of carp. Electron dense bodies were observed in the cytoplasm of the primary cell blood stages. Infected proximal‐tubular epithelial cells showed highly vacuolated cytoplasm and pycnotic nuclei.
Cosmetophilus vonones, N. G., N. Sp., (Apicomplexa: Actinocephalidae) in the Harvestman Vonones sayi (Arachnida: Cosmetidae)
Authors: COKENDOLPHER JAMES C.
Published: May 2007

The gregarine Cosmetophilus vonones, n. g., n. sp. (Sporozoasida: Actinocephalidae: Acanthosporinae) from the intestine and intestinal caeca of the harvestman Vonones sayi (Simon) (Opiliones: Cosmetidae) is described. The new internal parasite is the first recorded from a harvestman in the New World and the second from the opilion suborder Laniatores. In addition to the records from the type locality in western Texas, additional collections are reported from the same host in central and eastern Texas and Tennessee.
Nutritional Requirements of Blastocrithidia culicis, a Trypanosomatid with an Endosymbiont1
Authors: de MENEZES MARIA CLAUDIA NORONHA DUTRA , ROITMANZ ISAAC
Published: May 2007

ABSTRACT. The symbiont‐containing Blastocrithidia culicis from Aedes vexans, unlike most lower trypanosomatids cultivated in defined media, require only three amino acids: methionine, histidine, and arginine; only three vitamins: thiamin, nicotinamide, and riboflavin; and neither heme nor purine. The bacterium‐like endosymbiont presumably provides the trypanosomatid's other essential nutrients.
Singhamoeba horticola (Singh & Hanumaiah, 1979) N. Comb., Type Species of Singhamoeba N. G.
Authors: SAWYER THOMAS K. , NERAD THOMAS A. , MUNSON DONALD A.
Published: May 2007

ABSTRACT. Small cyst‐forming amoebae described as Schizopyrenus horticolus Singh & Hanumaiah, 1979, were cultured from sediment samples taken from three sites along the Chester River, Kent County, MD. Morphological studies on cysts and trophozoites showed sufficient differences between Sch. horticolus and the type species, Sch. russelli Singh, 1952, to justify its removal from that genus. A new genus, Singhamoeba is proposed to accommodate the species horticolus.
Observations on a Rare Ciliate, Discomorphella pectinata (Levander, 1894) Corliss, 1960
Authors: TUFFRAU MICHEL
Published: May 2007

ABSTRACT. Specimens of the rare ciliate Discomorphella pectinata (Levander, 1894) Corliss, 1960 were impregnated with silver nitrate in 1963. The body is discoid, about 60 μm long, laterally compressed and adorned with long spines. The somatic kineties on the right and left sides are sparse, sometimes disorganized, and locally without cilia. The oral zone has a complex infraciliature that lies above two series of ventral kineties and below a large, visor‐like, epistomial fringe. The arrangement of this fringe is similar to that observed in some other heterotichous ciliates, notably members of the Metopidae and Caenomorphidae.
The Molecular Biology of a Bacterial Endosymbiont1
Authors: SOLDO A. T. , BRICKSON S. A. , VAZQUEZ D.
Published: May 2007

ABSTRACT. The marine ciliate Parauronema acutum harbors a group of symbiotic bacteria, termed xenosomes, which reside exclusively in the cytoplasm where they grow and divide in a remarkable synchronism with the host. When released into the ambient culture medium by gentle rupture of the protozoans, the symbionts can infect homologous as well as heterologous Parauronema stocks and, oddly, Miamiensis avidus, a distantly related marine ciliate. Xenosomes from certain Parauronema stocks can kill other marine ciliates, particularly those of the genus Uronema. Our principal aims with this host‐symbiont system have been to study, at the molecular level, the nature of the interaction of the xenosome with the host, infection and the killer effect. Our most recent investigations have been directed toward establishing the phylogenetic origins of the symbionts using molecular approaches. This paper summarizes our previous work and updates our more recent studies on the association of a bacterial symbiont with its protozoan host. The reader is referred to previous reviews for more details on the subject [4, 5].
A Fine Structure Study of Physarum polycephalum During Transformation from Sclerotium to Plasmodium: A Six‐Stage Description
Authors: ANDERSON O. ROGER
Published: May 2007

ABSTRACT. Physarum polycephalum is classified presently as a sarcodinid in the class Eumycetozoea. It produces a sclerotial dormant stage consisting of a crustose deposit containing nucleated spherules of cytoplasm enclosed within a honey‐comb‐like matrix of organic walls. When rehydrated, the sclerotium reverts to a plasmodium: 1) the spherules become increasingly vacuolated, 2) electron‐dense granules become dispersed within expanding vacuoles, and 3) pseudopodial extensions develop from the periphery of the spherule cytoplasm, penetrating the fragmenting walls, and making interconnections with surrounding spherules, eventually leading to a fully reticulated plasmodium. Six stages are identified during reversion from sclerotium to plasmodium in laboratory cultures, and their successive appearance was mapped over time. The six stages are: 1) sclerotial stage with crenulated nuclei, 2) cytoplasmic activation with smooth nuclear envelopes, 3) initiation of pseudopodial protrusions, 4) pseudopodial penetration into or across walls, 5) cytoplasmic interconnections among spherules with wall disintegration, and 6) fully formed cytoplasmic network as plasmodium. Cytochrome c oxidase activity, expressed per unit protein content of the homogenate, remains fairly constant throughout the developmental sequence, whereas acid phosphatase activity, expressed per unit protein concentration, is somewhat lower in the sclerotium than in subsequent stages of development after hydration.
Separation of Soluble Amoebicidal and Tumoricidal Activity of Activated Macrophages
Authors: FISCHER‐STENGER KRISTA , CABRAL GUY A. , MARCIANO‐CABRAL FRANCINE
Published: May 2007

ABSTRACT. Macrophage‐conditioned medium (MøCM) prepared from mouse peritoneal macrophages activated in vivo with bacillus Calmette‐Guérin (BCG) or Propionibacterium acnes and triggered with lipopolysaccharide in vitro contained tumoricidal and amoebicidal activity. The murine fibroblast cell line L929 was used as the indicator of tumoricidal activity and Naegleria fowleri amoeba was used to detect amoebicidal activity in MøCM. The protease inhibitor, soybean trypsin inhibitor, decreased tumoricidal activity but had little effect on amoebicidal activity in MøCM. Anti‐TNF antiserum inhibited tumoricidal activity in MøCM. The antiserum reduced amoebicidal activity in BCG‐activated MøCM but had no effect on amoebicidal activity in P. acnes‐activated MøCM. Recombinant TNF, rIL‐1, or rIL‐1 independently did not affect cytolysis of amoebae. Also, rTNF had no effect on the growth of amoebae. Preparative flat‐bed electrofocusing of BCG‐activated MøCM yielded fractions that exhibited different amoebicidal and tumoricidal activity profiles. Three domains of activity were analyzed (acidic, neutral, and basic). Anti‐TNF antiserum eliminated tumoricidal activity, but not amoebicidal activity, in fractions from the acidic domain. A combination of anti‐TNF and anti‐IL‐1 antisera failed to eliminate amoebicidal activity in fractions from the basic domain. These results indicate that different factors are responsible for macrophage amoebicidal and tumoricidal activity. The amoebicidal factors in MøCM affected cytolysis of several species of amoebae.
Entamoeba Motility: Dynamics of Cytoplasmic Streaming, Locomotion and Translocation of Surface‐Bound Particles, and Organization of the Actin Cytoskeleton in Entamoeba invadens
Authors: BAILEY GORDON B. , DAY DIANE B. , McCOOMER NORMAN E.
Published: May 2007

ABSTRACT. The dynamics of cytoplasmic streaming, retrograde translocation of externally bound particles and locomotion by Entamoeba invadens were compared. Locomoting amoebae were monopodial, exhibited fountain flow cytoplasmic streaming and translocated externally bound erythrocytes to the rear of cells. The rates of rearward flow of peripheral cytoplasmic vacuoles and of the externally bound particles were equal to the rate of cell forward locomotion. Rhodamine‐phalloidin staining revealed a distinct cortical polymerized actin cytoskeleton. This was least evident about the periphery of the advancing pseudopod, increased in density toward the rear of the cell and was most concentrated in the uroid. A monoclonal anti‐eucaryotic actin antibody, which recognized monomeric Entamoeba actin on immunoblots, stained trophozoites by indirect immunofluorescence throughout the cytoplasm, but not in the cortical regions stained by rhodamine‐phalloidin. This and other evidence implied that the antibody recognized only unpolymerized actin in Entamoeba. We propose that locomotion, cytoplasmic streaming and translocation of externally bound particles are driven by a common actin‐based mechanism in Entamoeba, possibly involving retrograde cortical actin flow and recycling.
Light and Electron Microscopic Description of Sphaerospora dicentrarchi N. Sp. (Myxosporea: Sphaerosporidae) from Wild and Cultured Sea Bass, Dicentrarchus labrax L.
Authors: SITJA‐BOBADILLA ARIADNA , ALVAREZ‐PELLITERO PILAR
Published: May 2007

ABSTRACT. A new myxosporean, Sphaerospora dicentrarchi n. sp., was found in numerous organs of wild and cultured sea bass (Dicentrarchus labrax L.). It is distinguished from all previously reported Sphaerospora spp. by the shape and small size of the spores, location in the host and its geographical distribution. Prevalence of infection was 100% and 83.5% in wild and cultured fish, respectively. Outstanding ultrastructural features are the presence of a binucleate sporoplasm, valvogenic spheroidal structures and capsulogenic lipid inclusions. Other data concerning ultrastructure and sporogenesis are presented.
Carbohydrate and Amino Acid Analyses of Giardia muris Cysts
Authors: MANNING PAUL , ERLANDSEN STANLEY L. , JARROLL EDWARD L.
Published: May 2007

ABSTRACT. Intact Giardia muris cysts were subjected to consecutive chloroform/methanol and 2% sodium dodecyl sulfate (SDS) extractions, and to amyloglucosidase treatment. The SDS‐insoluble, amyloglucosidase‐fast cyst walls (ACW) were further incubated with chymotrypsin, trypsin, papain, or pronase. Low voltage scanning electron microscopy revealed no discernible change in the ultrastructure of the filamentous layer of the cyst wall following any of these treatments. Affinity for cyst wall‐specific monoclonal antibody (Meridian Diagnostics, Cincinnati. OH) was also retained after all treatments. Periodic acid‐Schiff staining and gas chromatography/mass spectrometry (GC/MS) of intact and treated cyst hydrolysates showed a significant reduction in the amount of glucose associated with the cyst (72 nmoles/106 intact cysts vs 1.9 nmoles/106 ACW) as a result of amyloglucosidase treatment, indicating that glucose is stored with in Giardia as an SDS‐insoluble polymer, Galactosamine was identified by GC/MS as the predominant sugar associated with both the ACW and the proteinase treated ACW (42 nmoles/106 ACW). High performance liquid chromatographic analysis of amino acids from intact and treated cyst hydrolysates revealed a marked reduction, but not elimination, of detectable quantities of identifiable amino acid residues (255 nmoles/106 intact cysts vs 6.8 nmoles/106 proteinase treated ACW). These results suggest that the filamentous layer of the cyst wall is primarily a carbohydrate peptide complex.
A Genetic Screen for Vegetative Gene Expression in the Micronucleus of Tetrahymena thermophila
Authors: KANEY ANTHONY R. , SPEARE VIRGINIA J.
Published: May 2007

ABSTRACT. The presence of a micronucleus with at least a small portion of the micronuclear genome appears to be indispensable for vegetative viability in the ciliate Tetrahymena thermophila. A genetic screen was devised to detect evidence of expression of essential genes in the vegetative micronucleus by identification of thermosensitive‐lethal mutations expressed in the absence of nuclear reorganization. Although control experiments demonstrated the efficacy of the method for induction and recovery of thermosensitive lethal mutations in micronuclear genes, no expressed mutations were recovered in the absence of nuclear reorganization. This finding complements the existing lack of convincing biochemical evidence for gene expression in the vegetative micronucleus and suggests that the essential function may involve genomic DNA sequences for which thermosensitive mutant alleles are not recoverable, or perhaps a non‐genomic component of the organelle.
Porphyrin Rings and Phospholipids: Stimulators of Cloning Efficiency in Certain Species of Tetrahymena
Authors: SCHOUSBOE P. , CHRISTENSEN S. T. , GHILADI M. , RASMUSSEN L.
Published: May 2007

ABSTRACT. Species of Tetrahymena, including T. vorax, T. thermophila, T. pyriformis, and T. pigmentosa, were tested for cloning efficiency in proteose peptone and in synthetic nutrient media to which were added hemin, protoporphyrin IX, chlorophyllin, or asolectin, an impure mixture of phospholipids. All species could be cloned with high efficiency in the crude media. In unsupplemented synthetic medium the cloning efficiencies were 0–10%, around 50%, around 50%, and 90–100% for T. thermophila, T. vorax, T. pyriformis, and T. pigmentosa, respectively. The first three were all stimulated to 90–100% by addition of the porphyrin or phospholipid compounds mentioned above. Uroporphyrin III and coproporphyrin I and III had no effect. We suggest that cells unable to form clones suffer from a lack of cellular energy. This situation may be alleviated by our additions: certain porphyrin rings may be built into cytochromes and phospholipids may be used as fuel. Thus, the synthetic media used so far for these ciliates have not been optimal.
In Vitro Tryptophan Catabolism by Leishmania donovani donovani Promastigotes
Authors: LEELAYOOVA SAOVANEE , MARBURY DEAN , RAINEY PETRIE M. , MACKENZIE NEIL E. , HALL JAMES EDWIN
Published: May 2007

ABSTRACT. Metabolism of tryptophan by promastigotes of Leishmania donovani donovani was investigated in cells suspended in a simple buffer solution supplemented with glucose. Metabolites from supernatant and lysed cell pellets were analyzed by capillary gas liquid chromatography and 13C nuclear magnetic resonance spectroscopy, with structural confirmation by gas liquid chromatography‐mass spectrometry. Tryptophan does not appear to serve as a carbon energy source for L. d. donovani promastigotes since parasites could survive for only short periods in buffer containing tryptophan without glucose, levels of tricarboxylic acid cycle intermediates remained unchanged in the presence of added tryptophan and label from [13C]tryptophan was not detected in any of the intermediates. Leishmania d. donovani catabolized l‐tryptophan via aminotransferase and aromatic lactate dehydrogenase reactions to form one major end product, indole‐3‐lactic acid. The activity of aromatic lactate dehydrogenase required manganese and was NADH‐dependent in these organisms that lack lactate dehydrogenase. Promastigotes taken from the mid‐log stage of growth produced higher concentrations of indole‐3‐lactic acid than those from the stationary stage. Conservation of a similar tryptophan catabolic pathway among four Leishmania species suggests the pathway is physiologically important to the parasites themselves.
Experimental Infection of Nosema sp. Ghose in an Unnatural Host Lesioderma sericorne
Authors: GHOSH SRIKANTA , SAHA KARNICA
Published: May 2007

ABSTRACT. Various doses of a microsporan parasite, Nosema sp., were fed to third and fourth instar larvae of Lesioderma sericorne that infested different types of stored grains. A spore dose of 3 × 103 spores/individual resulted in a 39% infection rate, reduction in larval and adult weights, and mean spore concentrations of 1.28 ± 0.2 × 108 spores/larva and 1.1 ± 0.2 × 108 spores/adult. At the above dose, mortality was not well marked (about 35% in larvae and 25% in adults). At 3 × 104 spores/individual, the rate of mortality increases to 80% in larvae and 60% in adults. However, more of the pest population (88% of larvae and 73% of adults) died at a dose of 3 × 105 spores/individual. This dose produced mean spore concentrations of 3.91 ± 0.2 × 108 spores/larva and 2.89 ± 0.2 × 108 spores/adult. Insect death was caused by heavy damage to gut epithelia and fat bodies.
Redescription of Phacodinium metchnikoffi (Ciliophora, Hypotrichida): General Morphology and Taxonomic Position
Authors: FERNANDEZ‐GALIANO DIMAS , CALVO PILAR
Published: May 2007

ABSTRACT Living and stained specimens of Phacodinium metchnikoffi, collected near Madrid, Spain, were studied under light microscopy. Infraciliature was stained using a silver‐impregnation procedure. The somatic infraciliature is composed of a relatively small number of discontinuous kineties, formed by groups of few kinetosomes (pallets). The buccal ciliature is composed of an adoral zone of membranelles and a paroral formation otherwise unknown in ciliates, with many short kineties, which lie on a rigid stem. We propose that P. metchnikoffi is a primitive hypotrich and, consequently, we present a new classification system for hypotrichs.
Determination of Taxonomic Status of Pathogenic and Nonpathogenic Entamoeba histolytica Zymodemes Using Isoenzyme Analysis
Authors: BLANC DOMINIQUE S.
Published: May 2007

ABSTRACT Entamoeba histolytica infection results in either asymptomatic colonization or invasion of host tissues leading generally to clinical symptoms. Zymodeme studies have demonstrated a correlation between isoenzyme profiles and clinical presentation. Thus, strains have been attributed to pathogenic or nonpathogenic groups according to their zymodeme. To determine the taxonomic relationship of these two groups, the isoenzyme profiles of 14 loci of 38 E. histolytica strains (pathogenic and nonpathogenic) and seven strains of other species of the same genus were analyzed. Genetic distance analysis clearly demonstrates the existence of two separate groups within the species E. histolytica.
Localization of a Toxoplasma gondii Rhoptry Protein by Immunoelectron Microscopy During and After Host Cell Penetration
Authors: SAFFER LINDA D. , MERCEREAU‐PUIJALON ODILE , DUBREMETZ JEAN‐FRANÇOIS , SCHWARTZMAN JOSEPH D.
Published: May 2007

ABSTRACT We immunolocalized a Toxoplasma gondii rhoptry protein (ROP1) before and after parasite host cell invasion of human fibroblasts and TG180 murine sarcoma cells by electron microscopy and immunogold labeling using either a monoclonal antibody (Tg49) or a monospecific rabbit antiserum (α249). At all stages of parasite growth ROP1 was found within the body but rarely within the peduncle of rhoptries, even in those that appeared empty. Immediately after host cell invasion ROP1 was associated with the parasitophorous vacuole membrane. Within hours after invasion the amount of ROP1 immunodetectable on the parasitophorous vacuole membrane was markedly decreased. The localization of ROP1 suggests a role in the early establishment of infection in host cells, consistent with previous work that has indicated that monoclonal antibodies to ROP1 (including the one used in these studies) interfere with the phenomenon of penetration enhancement.
Arginine Catabolism by Leishmania donovani Promastigotes
Authors: BLUM J. JOSEPH
Published: May 2007

ABSTRACT Leishmania donovani promastigotes were grown to late log phase, washed and resuspended in iso‐osmotic buffer containing L‐arginine, and the rate of urea formation was then measured under various conditions. Addition of glucose or mannose activated urea formation, whereas 2‐deoxyglucose inhibited and 6‐deoxyglucose had no effect. Addition of alanine or of α‐aminoisobutyrate inhibited urea formation, alanine causing a greater inhibition than α‐aminoisobutyrate. Addition of leucine, proline, glycine, or lysine had no effect on urea formation. The presence of glutamate also increased the rate of urea formation from arginine, but to a lesser extent than did glucose. The presence of both glucose and alanine caused no net change in urea formation, whereas the inhibitory effect of alanine exceeded the activating effect of glutamate, so that a small inhibition in the rate of urea formation occurred in the presence of both alanine and glutamate. Cells grown to 3‐day stationary phase had a markedly reduced rate of arginine catabolism to urea, but the activating effect of glucose and the inhibitory effect of alanine were qualitatively similar to their effects on late log phase cells. Addition of water to cells suspended in buffer also inhibited urea formation, but this appeared to be due primarily to the release of alanine caused by the hypo‐osmotic stress. Addition of mannitol to cells suspended in buffer caused a small inhibition of arginine catabolism. Addition of dibutyrylcyclic AMP, 3′,5′‐cyclic GMP, phorbol myristic acid, or A23187 had no effect on the rate of urea formation from arginine. It is suggested that the effects of glucose and 2‐deoxyglucose on arginine catabolism depend largely upon the nature of their metabolites, whereas the effects of the various amino acids examined depend largely on the extent to which they interfere with or enhance arginine transport into the cells.
Microsporidian Spore Envelope Keratins Phosphorylate and Disassemble During Spore Activation
Authors: WEIDNER EARL , HALONEN SANDRA K.
Published: May 2007

The microsporidian spore stage of the nerve parasite, Spraguea lophii, consists of outer envelope stabilized in part by keratins, including K4 and K13. The nonepidermal K4 and K13 keratins were found only in the spore envelope and were absent in the internal microsporidian sporoplasm. At the time of spore activation, the keratin‐based outer spore envelope assemblage dissociated and became phosphorylated when the spores were placed in the presence of labeled ATP. Verapamil or lanthanum, agents which block S. lophii spore activation, also blocked spore envelope keratin disassembly and phosphorylation when the spores were incubated in activation medium with labeled ATP. However, after the removal of the verapamil or lanthanum, the spores regained the capacity to activate in discharge medium and the keratin analogues appeared to dissociate and phosphorylate.
Vance Tartar: A Unique Biologist
Authors: FRANKEL JOSEPH , WHITELEY ARTHUR H.
Published: May 2007

ABSTRACT. Vance Tartar (1911‐1991) has made major discoveries concerning morphogenesis, patterning, and nucleocytoplasmic relations in the giant ciliate Stentor coeruleus, mostly by means of hand‐grafting using glass microneedles. This article provides a chronological account of the major events of Vance Tartar's life, a brief description of some of his major scientific achievements, and a discussion of his distinctive personality and multifaceted interests. It concludes with a consideration of how his unique style of life and work contributed to his equally unique seientific contributions.
Septate Gregarines From Reticulitermes Flavipes and Reticulitermes Virginicus (Isoptera: Rhinotermitidae)
Authors: HALL DONALD W. , HOSTETTLER NIKLAUS
Published: May 2007

ABSTRACT. The gregarine parasites of Reticulitermes virginicus and Reticulitermes flavipes begin their development as trophozoites attached to the midgut epithelium by a small button‐shaped epimerite. the epimerite is lost when the parasite becomes free‐living in the gut lumen as a solitary gamont. Syzygy is late and was not observed. When full‐grown, gamonts enter the hemocoel and fuse in pairs to form large gametocysts that are attached to the midgut of the termite by a duct. Thousands of sporocysts are formed within the original gametocyst. the mature sporocysts are released into the lumen of the midgut through the connecting duct. They are then passed out with the feces. These gregarines are believed to be identical to Gregarina termitis Leidy which was described from a single gamont and later erroneously placed in the genus Hirmocystis by Henry.
Naegleria‐Like Cysts In Cretaceous Amber From Central Kansas
Authors: WAGGONER BENJAMIN M.
Published: May 2007

ABSTRACT. Fossil protist cysts are reported from the mid‐Cretaceous amber of Ellsworth County, Kansas, which is rich in terrestrial microfossils but contains no known macrofossils. On the basis of their distinctive morphology, the cysts can be referred to the genus Naegleria (Schizopyrenida); they most closely resemble cysts of the living species Naegleria gruberi. This is the first known fossil record for this group of amoebas. the current phylogenetic position and paleoecological role of Naegleria are discussed in relation to this find; it provides direct confirmation of morphological stasis in this group, which had previously been inferred from rRNA sequence divergence data.,
Leishmania Differentiation in Natural and Unnatural Sand Fly Hosts1
Authors: WALTERS LAUREL L.
Published: May 2007

ABSTRACT. Leishmania differentiation in the gut of phlebotomine sand flies was evaluated based on five light and electron microscopic studies of natural (Leishmania panamensis/Lutzomyia gomezi, Leishmania chagasi/Lutzomyia longipalpis) and unnatural (Leishmania mexicana/Lutzomyia abonnenci, Leishmania panamensis/Phlebotomus papatasi, Leishmania major/Lutzomyia longipalpis) life cycles. In the bloodmeal, transformation of amastigotes into stumpy promastigotes occurred before or during division. Further division in pairs or rosettes resulted in the development of spatulate and/or elongate nectomonad (free‐swimming) promastigotes. Elongate, short, and metacyclic nectomonad promastigotes, and nectomonad paramastigotes were present in the midgut lumen. Dividing short promastigotes predominated in the cardia, and appeared to generate metacyclic forms which were observed in three life cycles. Haptomonad (attached) forms of Leishmania panamensis in the hindgut were primarily spatulate promastigotes (natural host) or pear‐shaped promastigotes (unnatural host); paramastigotes and dividing forms were rare. At the stomodeal valve, short haptomonad promastigotes predominated in unnatural hosts, while both short and pear‐shaped haptomonads were abundant, along with paramastigotes in natural hosts. Haptomonad paramastigotes and pear‐shaped promastigotes colonized the esophagus, while paramastigotes predominated in the pharynx. Metacyclics were free‐swimming in the lumen of the foregut.
Myosin‐Like Protein (MR 175,000) In Gregarina Blaberae
Authors: GHAZALI MACHHOUR , SCHREVEL JOSEPH
Published: May 2007

ABSTRACT. A myosin‐like protein (Mr 175,000) was detected in the parasitic protozoan Gregarina blaberae, by both immunofluorescence and immunoblotting of one‐ and two‐dimensional electrophoresis gels using anti‐myosin antibodies. This protein was present in the trophozoite ghost but not in the cytoplasmic extract, nor in extract from the sexual stage, suggesting a protein‐stage‐dependent expression. the protein tightly bound to the cortical membranes was insoluble at low ionic strength, or in detergent solutions, but could be extracted from Gregarina ghosts by 6 M urea in high ionic strength solution (0.5 M NaCI) and in the presence of reducing agents (20 mM DTT). the protein was localized by indirect immunofluorescence in the cortex of the epimerite, in the fibrillar disc (the socalled septum) separating the proto‐ and the deutomerite segments, in the contractile ring or sphincter at the top of the protomerite, and as longitudinal lines underlying the G. blaberae epicyte folds. the presence of both actin‐like and myosin‐like proteins would be consistent with a role in gliding and other cell motility processes of this parasite.
Ultrastructural Characterization of Meiospores of Six New Species of Amblyospora (Microsporida: Amblyosporidae) from Northern Aedes (Diptera: Culicidae) Mosquitoes
Authors: ANDREADIS THEODORE G.
Published: May 2007

ABSTRACT. The ultrastructure of meiospores of six different species of Amblyospora found infecting larval mosquitoes of Aedes abserratus, Aedes aurifer, Aedes cinereus, Aedes excruciates, Aedes sticticus, and Aedes stimulans are described. Meiospores of all species exhibited characteristics typical for the genus Amblyospora including: a single nucleus, a large posterior vacuole, a thick undulating exospore and thinner endospore, a bipartite and lamellate polaroplast with more tightly stacked membranes in the proximal region, and an anisofilar polar filament with distal coils reduced in thickness. Distinct differences were found in the arrangement and number/ ratio of coils formed by the broad basal and narrow distal portions of the polar filament. These differences, when quantified and averaged, were unique from all other mosquito‐parasitic species that have been examined ultrastructurally. Information on parasite development, natural field prevalence and transmission to suspected intermediate copepod hosts is presented. The creation of six new species, Amblyospora abserrati, Amblyospora auriferi, Amblyospora cinerei, Amblyospora excrucii, Amblyospora stictici, and Amblyospora stimuli is proposed. Synonymies and complete host lists of all forms and species of Amblyospora described from mosquitoes are given.
Accumulation of Telomerase RNA and Telomere Protein Transcripts during Telomere Synthesis in Euplotes
Authors: PRICE CAROLYN M. , ADAMS ANGELA K. , VERMEESCH JORIS R.
Published: May 2007

ABSTRACT. In the ciliate Euplotes crassus a complex series of developmental events lead to formation of a new macronucleus. Millions of telomeres are synthesized during this process. We have shown that transcript levels are tightly regulated throughout Euplotes conjugation and macronuclear development. Thus, expression of gene products needed for macronuclear development and telomere synthesis appears to be controlled at the level of RNA abundance. To learn more about the role played by telomerase and the Euplotes telomere protein during telomere synthesis, we have correlated changes in the abundance of telomerase RNA and telomere protein mRNA transcript with specific developmental events. Telomerase RNA levels increase steadily during the early stages of macronuclear development and reach a peak just after telomere addition. The telomere protein transcript rises and falls twice during conjugation and then rises again at the time of telomere addition. The increases in transcript levels during conjugation parallel micronuclear division suggesting that the telomere protein is synthesized at this time and hence may have a micronuclear function.
Comparative Fine Structural Investigations of Interphase and Mitotic Nuclei of Vampyrellid Filose Amoebae
Authors: RÖPSTORF PETER , HÜLSMANN NORBERT , HAUSMANN KLAUS
Published: May 2007

The nuclei of trophozoites and digestive cysts as well as mitotic nuclei of several species of the vampyrellids Vampyrella, Gobiella, Hyalodiscus, Arachnula, and Leptophrys were investigated by electron microscopy. Except for some species of the genus Hyalodiscus, the vampyrellids are generally multinucleate. The nuclei of the trophozoite stage are in interphase. These nuclei are spherical, except for the genus Arachnula, which reveals elongated nuclei. In digestive cysts of all vampyrellids the nuclei enlarge and the pars granulosa of the nucleoli becomes prominent. Karyokineses take place synchronously in older digestive cysts, which transform into reproductive cysts. The nuclei divide by closed intranuclear orthomitosis. In telophase the old nuclear envelope disintegrates and a new one is rearranged. Only in the genus Leptophrys the nuclear envelope decomposes before telophase. Neither centrioles nor MTOC‐plaques have been found in any stage of mitosis. After karyokinesis the cell divides inside the cyst or when leaving the cyst.
Inhibition of In Vitro Splicing of a Group I Intron of Pneumocystis carinii
Authors: LIU YONG , TIDWELL RICHARD R. , LEIBOWITZ MICHAEL J.
Published: May 2007

Unlike its mammalian hosts, the opportunistic fungal pathogen Pneumocystis carinii harbors group I self‐splicing introns in its chromosomal genes encoding rRNA. This difference between pathogen and host suggests that intron splicing is a promising target for chemotherapy. We have found that intron splicing in vitro is inhibited by the anti‐Pneumocystis agent pentamidine and by a series of pentamidine analogues, as well as by some aminoglycosides, tetracycline, L‐arginine and ethidium bromide. Further studies will be needed to determine if this is the mechanism of action of pentamidine against P. carinii.
Changes in ATP Concentration, Mitochondrial Structures, and Rhodamine 123 Binding in Two Marine Dinoflagellates Cultured in the Presence of Parathion
Authors: PREVOT PAUL , SOYER‐GOBILLARD MARIE‐ODILE
Published: May 2007

Parathion, an organophosphorus insecticide, is highly toxic to the two free‐living marine dinoflagellates Prorocentrum micans Ehrenberg (autotrophic) and Crypthecodinium cohnii Biechler (heterotrophic). To study its non‐antiacetylcholinesterase action we assessed its effect on the mitochondrial system, as shown by changes in intracellular ATP concentration and in rhodamine 123 fluorescence evaluated by image analysis. The technique of image analysis permits direct assessment of changes in the overall activity of mitochondria in living cells. Mitochondrial structures were also examined in the electron microscope. The three methods of investigation yielded complementary results. In P. micans, parathion noticeably altered mitochondria but did not significantly alter ATP concentrations. In C. cohnii, however, mitochondrial disturbance was slight, whereas ATP increased greatly. We think, therefore, that parathion has different effects on mitochondria in the two organisms, and in particular that it increases mitochondrial activity in C. cohnii.
A Novel Opioid Mechanism Seems to Modulate Phagocytosis in Tetrahymena
Authors: RENAUD FERNANDO L. , COLON IRIS , LEBRON JOSE , ORTIZ NERIAN , RODRIGUEZ FERNANDO , CADILLA CARMEN
Published: May 2007

ABSTRACT. We have previously reported that a β‐endorphin‐like substance inhibits phagocytosis in Tetrahymena perhaps by a mu‐like opioid receptor. We now report a further characterization of the elements involved in the signal transduction mechanism of this opioid. Affinity chromatography followed by immunoblots of both intracellular extracts and extracellular medium reveal the presence of two main proteins of 64 and 75 kDa. These molecular weights are much higher than that of any known opioid peptide or precursor protein and suggest that we may be dealing with either a novel opioid or with proteins that by chance cross‐react with anti‐β‐endorphin antibody. Nevertheless, when the biological activity of these proteins was tested it was found that they had an effect similar to that of mammalian β‐endorphin, namely inhibition of phagocytosis by a naloxone‐reversible mechanism. We have probed a size‐selected Tetrahymena library with a pro‐opiomelanocortin probe and have obtained several positive clones; the sequencing of their inserts should establish whether we are dealing with a bona fide member of the opioid family. Another aspect we have been studying is the G‐proteins which appear to be involved in the modulation of phagocytosis. We have found, by means of Western blotting (using an antibody against the conserved GTP‐binding region of the α‐subunit), two bands of 51 and 59 kDa; no α‐subunit of 59 kDa had been reported previously and may represent a novel G‐protein. In spite of these differences, the opioid signal transduction mechanism appears to remarkably resemble that present in more complex organisms.
Chemical Signaling in Ciliates
Authors: LUPORINI PIERANGELO , VALLESI ADRIANA , MICELI CRISTINA , BRADSHAW RALPH A.
Published: May 2007

ABSTRACT. For long, our knowledge of the biology of ciliate pheromones has long relied solely upon the study of the two structurally unrelated “gamones” identified in culture filtrates of a Blepharisma species. However, the characterization of a number of polypeptide pheromones secreted by Euplotes raikovi and E. octocarinatus has now established that structural relationships of homology usually link these molecules, which is consistent with the genetic basis of the mating type systems evolved by these species. In this context, our growing appreciation of the conserved and variable elements of the pheromone architecture should foster progress in the understanding of pheromone‐receptor interactions and thus, provide important clues into pheromone mechanisms of action.
Isolation of N‐Acety‐β‐Hexosaminidase from Acanthamoeba castellanii
Authors: BALDWIN KATE M. , BOWERS BLAIR
Published: May 2007

ABSTRACT. The lysosomal enzyme N‐acetyl‐β‐hexosaminidase (βhex) has been purified from Acanthamoeba castellanii growth medium by a three step procedure. The enzyme was precipitated with ammonium sulfate, partially purified on a DE52 column and purified to homogeneity on an affinity column. The purified βhex appeared to be a monomer with a molecular mass of 58 kDa and a pI of approximately 5.8. The enzyme activity in growth medium at RT was stable for several months. The purified βhex was enzymatically deglycosylated and injected, into two rabbits to make polyclonal antibodies. One antiserum was specific for βhex, but the other stained many bands on immunoblots of whole cell preparations. Using fluorescently labelled secondary antibodies we have determined that both antisera stain digestive vacuoles in the Acanthamoeba cytoplasm, and do not stain the contractile vacuole. The multi‐specific antiserum had high avidity for βhex, but also stained the carbohydrate portion of other molecules. These other molecules may be lysosomal enzymes as well, since the activity of several other lysosomal enzymes was partially immunoprecipitable with the antiserum. We plan to use these antibodies to study traffic patterns among the variety of vacuolar structures in Acanthamoeba cytoplasm.
Fractionation of Different Life Cycle Stages of Microsporidia Nosema grylli from Crickets Gryllus bimaculatus by Centrifugation in Percoll Density Gradient for Biochemical Research
Authors: SELEZNEV KONSTANTIN V. , ISSI IRMA V. , DOLGIKH VIACHESLAV V. , BELOSTOTSKAYA GAUNA B. , ANTONOVA OLGA A. , SOKOLOVA JULIA J.
Published: May 2007

ABSTRACT. A new method of fractionation and purification of different life cycle stages of microsporidia Nosema grylli, parasitizing the fat body of cricket Gryllus bimaculatus, by centrifugation in Percoll density gradient is elaborated. The whole procedure can be summarized as: 1) infected fat body preparation, 2) homogenization in buffer and filtration through cotton wad and filter paper, 3) first centrifuging, resulting in the separation of the pellet into three layers containing different life cycle stages, 4) second centrifuging of the chosen layer in Percoll density gradient, 5) washing out the Percoll from the fraction under study. After centrifugation in Percoll density gradient, meronts and early sporonts form a band in the area corresponding to density 1.016 g/ml. Mature spores form the pellet at the bottom of centrifuge tube, while immature spores are distributed throughout the layer of 1.016 g/ml up to the bottom of the centrifuge tube, according to their buoyant densities. The offered technique is simple, it takes about one hour and may become a routine procedure for biochemical studies on microsporidia.
Detection and Immunolocalization of Human Erythrocyte Spectrin Immunoanalogues in Toxoplasma gondii (Protozoan, Parasite)
Authors: GHAZALI MACHHOUR , RODIER MARIE‐HELENE , EL MOUDNI BRAHIM , BABIN PHILIPPE , FERNANDEZ BEATRICE , JACQUEMIN JEAN‐LOUIS
Published: May 2007

ABSTRACT. We demonstrated here the presence of proteins antigenically related to human erythroid spectrin in the parasitic protozoan Toxoplasma gondii. A high molecular weight doublet (M, 245‐240,000), present in equimolar ratio, and low molecular weight polypeptides (M, 75,000) were reacted with monoclonal and polyclonal anti‐human erythroid spectrin antibodies on electroblotted nitrocellulose sheets. Indirect immunofluorescence assay clearly showed that these proteins were localized in the anterior pole of the organism. Immunogold staining further revealed specific labeling of conoid, rhoptries, micronemes, and dense granules of the apical complex. The presence of the M, 245–240,000 doublet and the M, 75,000 spectrin‐like proteins in the anterior pole of T. gondii may probably be consistent with a structural stabilizer function in its organciles which are suspected to be involved in the process of host cell invasion.
Alternation of Actinosporean and Myxosporean Phases in the Life Cycle of Zschokkella nova (Myxozoa)
Authors: USPENSKAYA ANNA V.
Published: May 2007

ABSTRACT. Experimental evidence has been gathered to show that the life cycle of the myxozoan gallbladder parasite Zschokkella nova Klokacewa, 1914, which infects the fish Carassius carassius, has a complex life cycle with alternation of two hosts (fish and Oligochaeta) and two developmental phases (myxosporean and actinosporean). The gut epithelium of the oligochaete, Tubifex tubifex, exposed experimentally to Z. nova, obtained from C. carassius, became infected with organisms resembling Actinosporea. The spore structure and cube‐like network of the interconnected spores is reminiscent of Siedleckiella silesica Janiszewska, 1952, although the spores are very different in size and number of sporoplasm nuclei. The life cycle of Z. nova resembles that of the whirling disease agent Myxosoma cerebralis described by Wolf and Markiw, which also alternates between fish and oligochaete hosts.