bluuebunny/crossref_metadata_2025 huggingface dataset:
Zschokkella mugilis N. Sp. (Myxosporea: Bivalvulida) from Mullets (Teleostei: Mugilidae) of Mediterranean Waters: Light and Electron Microscopic Description
Authors: SITJÀ‐BOBADILLA ARIADNA , ALVAREZ‐PELLITERO PILAR
Published: May 2007

A new Myxosporea, Zschokkella mugilis n. sp., was found in the gall bladder of several mugilids. It is distinguished from all previously reported Zschokkella from mugilids by the absence of valve ornamentation and from other species by the size of the spores. Prevalence of infection was 62.5% for Mugil capito, 70% for M. cephalus and 64.3% for Liza saliens. Plasmodia with rhizoids attached to epithelial cells appeared to compromise the host as evidenced in light and transmission electron micrographs presented herein. General ultrastructure and disporous sporogenesis of Z. mugilis resembled other Myxosporeans, but sporogonic cells did not seem to be formed in pansporoblasts.
Corticocolpoda kaneshiroae N. G., N. Sp., a New Colpodid Ciliate (Protozoa, Ciliophora) from the Bark of Ohia Trees in Hawaii
Authors: FOISSNER WILHELM
Published: May 2007

Corticocolpoda kaneshiroae n. g., n. sp. was discovered in the bark of Ohia trees (Metrosideros polymorpha) from the Hawaiian Archipelago. Its morphology and infraciliature were studied in live cells, with the scanning electron microscope, as well as in specimens impregnated with protargol, silver nitrate, and silver carbonate. The new genus, Corticocolpoda, belongs to the family Colpodidae and is unique in having a left oral ciliary field (polykinetid) composed of 13–20 equidistantly spaced, paired rows of monokinetids. The new species, C. kaneshiroae, measures 100–300 × 60–250 μm and has a huge vestibulum used to capture large food items, mainly other ciliates. The oral ciliary fields are within the vestibulum and of equal length; the right field is a paroral membrane composed of a single row of dikinetids. Several micronuclei are attached to the ellipsoid macronucleus. The mucocysts are inconspicuous and arranged around the somatic dikinetids. The resting cyst is globular and has a 1–2 μm thin, firm, yellowish inner wall and a 20‐μm‐thick, fragile, hyaline outer wall. Convergent evolutionary paths and a possible polyphyly of the Colpodidae are discussed. An improved key to the genera of the family Colpodidae is provided. Twenty‐three species of ciliates and one flagel***iate (Hemimastix amphikineta), which occurred together with C. kaneshiroae, are new for the fauna of Hawaii and listed in the ecology section.
Description of Chytridiopsis Trichopterae N. Sp. (Microspora, Chytridiopsidae), A Microsporidian Parasite of the Caddis Fly Polycentropus Flavomaculatus (Trichoptera, Polycentropodidae), With Comments On Relationships Between the Families Chytridiopsidae and Metchnikovellidae
Authors: LARSSON J. I. RONNY
Published: May 2007

ABSTRACT. The microsporidium Chytridiopsis trichopterae n. sp., a parasite of the midgut epithelium of larvae of the caddis fly Polycentropus flavomaculatus found in southern Sweden, is described based on light microscopic and ultrastructural characteristics. All life cycle stages have isolated nuclei. Merogonial reproduction was not observed. the sporogony comprises two sequences: one with free spores in parasitophorous vacuoles, the other in spherical, 5.6‐6.8 μm wide, sporophorous vesicles which lie in the cytoplasm. the free sporogony yields more than 20 spores per sporont. the vesicle‐bound sporogony produces 8, 12 or 16 spores. the envelope of the sporophorous vesicle is about 82 nm thick and layered. the internal layer is the plasma membrane of the sporont; the surface layer is electron dense with regularly arranged translucent components. Both spore types are spherical. They have an ∼ 35‐nm thick spore wall, with a plasma membrane, an electron‐lucent endospore, and an ∼ 14‐nm thick electron‐dense exospore. the polar sac is cup‐like and lacks a layered anchoring disc. the polar filament is arranged in two to three isofilar coils in the half of the spore opposite the nucleus. the coupling between the polar sac and the polar filament is characteristic. the surface of the polar filament is covered with regularly arranged membraneous chambers resembling a honeycomb. There is no polaroplast of traditional type. the cytoplasm lacks polyribosomes. the nucleus has a prominent, wide nucleolus. the two spore types have identical construction, but differ in dimensions and electron density. Free living spores are about 3.2 μm wide, the diameter of the polar filament proper is 102‐187 nm, the chambers of the honeycomb are 70‐85 nm high, and the polar sac is up to 425 nm wide. Living spores in the vesicle‐bound sporogony are about 2.1 μm wide, the polar filament measures 69‐102 nm, the chambers of the honeycomb are about 45 nm high, and these spores are more electron dense. Comparisons of cytology (especially the construction of the spore wall and the polar filament and associated structures) and life cycles reveal prominent differences among the Chytridiopsis‐like microsporidia, and close relationships between the families Chytridiopsidae and Metchnikovellidae.
Common Epitopes In the Circumsporozoite Proteins of Plasmodium Berghei and Plasmodium Gallinaceum Identified By Monoclonal Antibodies to the P. Gallinaceum Circumsporozoite Protein
Authors: ROCHA ELIANA M. M. , HOLLINGDALE MICHAEL R. , SINA BARBARA , LELAND PAMELA , LOPES JOSÉ D. , KRETTLI ANTONIANA U.
Published: May 2007

ABSTRACT. Monoclonal antibodies that react with the circumsporozoite protein of the avian malaria Plasmodium gallinaceum sporozoites also reacted with circumsporozoite protein of the rodent malaria Plasmodium berghei. Two types of reactivity were identified: 1) two monoclonal antibodies reacted with P. berghei sporozoite protein by enzyme‐linked immunosorbent assay, Western blot and indirect immunofluorescence antibody, 2) six other monoclonal antibodies reacted with P. berghei sporozoites by ELISA and Western blot only. We studied whether these differences could be explained by reactivity in enzyme‐linked immunosorbent assay with different P. berghei circumsporozoite peptides. Although all P. gallinaceum monoclonal antibodies reacted with the P. berghei repeats, the first group reacted with a conserved peptide sequence, N1, whereas the second group did not. These results suggest that circumsporozoite proteins from P. gallinaceum and P. berghei share common epitopes. the biological significance of our finding is not yet clear. Indeed, the cross‐reactive monoclonal antibodies giving a positive indirect immunofluorescence antibody with the P. berghei sporozoites only caused a borderline effect on the living P. berghei parasites in vitro as measured by inhibition of sporozoite infectivity.
Lateromyxa gallica N. G., N. Sp. (Vampyrellidae): A Filopodial Amoeboid Protist With A Novel Life Cycle and Conspicuous Ultrastructural Characters
Authors: HÜLSMANN NORBERT
Published: May 2007

ABSTRACT. A large, uni‐ or multinucleate vampyrellid rhizopod, Lateromyxa gallica n. g., n. sp., has been isolated several times from two lakes in central France between September 1973 and August 1989 and cultivated for several months or years under laboratory conditions. No essential variations of feeding behaviour were found over the time; all isolated strains invade the trichomes of the green alga Oedogonium and move, divide and encyst inside the vanished plant cells. Penetration is performed by attacking the cross walls and only primary attacks are directed against the lateral cell walls of the algae. These findings contrast with the behaviour, life cycles and fine structure of all known species of the genera Vampyrella, Hyalodiscus, Arachnula and Gobiella. The establishment of a new genus, Lateromyxa, with the type species Lateromyxa gallica is therefore proposed.
Species Structure in Euplotes crassus (Ciliophora, Hypotrichida)
Authors: GIANNI ALESSANDRO , PIRAS LUCIANA
Published: May 2007

ABSTRACT. We observed different low salinity tolerances between two groups of populations of Euplotes crassus. After mating analysis, the less tolerant populations could be assigned to three mating groups. Two of them were separated by preconjugative barriers but both conjugated with a third one. A breeding test showed evidence of (potential) introgression mediated by this “bridging” group. On the other hand, the more tolerant populations formed a fourth mating group unable to conjugate with the others and characterized by distinct zymogram patterns. We conclude that natural introgression among the studied populations is not complete and that the species structure of E. crassus comprises intrafertile sets of populations among which gene flow may be difficult or virtually absent.
Quassinoids Exhibit Greater Selectivity Against Plasmodium Falciparum Than Against Entamoeba Histolytica, Giardia Intestinalis Or Toxoplasma Gondii In Vitro
Authors: WRIGHT COLIN W. , ANDERSON MARGARET M. , ALLEN DAVID , PHILLIPSON J. DAVID , KIRBY GEOFFREY C. , WARHURST DAVID C. , CHANG HERNAN R.
Published: May 2007

ABSTRACT. The in vitro activities of a series of quassinoids against Plasmodium falciparum, Entamoeba histolytica, Giardia intestinalis and Toxoplasma gondii have been compared with their in vitro cytotoxic effects against KB cells (human epidermoid carcinoma of the nasopharynx). All of the compounds tested were more toxic to KB cells than to G. intestinalis, but four (ailanthinone, bruceine D, brusatol and glaucarubinone) were slightly less toxic to KB cells than to E. histolytica. Glaucarubinone was similarly more toxic to intracellular T. gondii than to KB cells but ailanthinone was more selective (36 times more toxic to T. gondii than to KB cells). All of the compounds were more toxic to P. falciparum than to KB cells; the most selective quassinoids—glaucarubinone, bruceine D, ailanthinone and brusatoi—were found to have toxicity/activity ratios of 285, 76, 48 and 32 respectively. These results suggest that quassinoids have a selective action on P. falciparum. Further studies to elucidate the basis for this are in progress.
The Effect of the Quantitative Protargol Stain and Lugol's and Bouin's Fixatives On Cell Size: A More Accurate Estimate of Ciliate Species Biomass
Authors: JEROME CHERYL A. , MONTAGNES DAVID J. S. , TAYLOR F. J. R.
Published: May 2007

ABSTRACT. The quantitative protargol stain (QPS) is used to estimate ciliate biomass and species composition from mixed field samples. Length, width, breadth and volume of live Euplotes sp., Eutintinnus sp., Strobilidium spiralis, Strombidium acutum, and Gymnodinium sanguineum were compared with 0.6% acid Lugol's fixed, 5% Bouin's fixed, and QPS cells. Cells shrank due to treatments (ANOVA and Tukey's test, α= 0.05). Protistan post‐fixation cell volume (as a percentage of live volume) was 55%‐80% for acid Lugol's fixed, 40%‐70% for Bouin's fixed, and 30%‐65% for QPS. Each species shrank to a different extent; cytostructural elements apparently alter the effect of fixation. Egestion is likely not the main cause of shrinkage since the autotroph, G. sanguineum, shrank to the same extent as the heterotrophs when stained by QPS. If field studies do not consider fixation effects on cell size, biomass may be underestimated. We recommend, for studies on planktonic ciliates, either acid Lugol's and QPS be used concurrently or QPS be used alone and biovolume values divided by 0.4 to correct for shrinkage. We stress that this is a rough estimate as this value ranges from 0.3 to 0.45 for planktonic protists.
Effects of Mesoionic Xanthine Analogs On Trypanosoma Musculi Development In Mice
Authors: SEN DILIP K. , MBAGWU GODWIN O. , ADSON ANTHONY
Published: May 2007

ABSTRACT. Two derivatives of the mesoionic thiazolo[3,2‐a]pyrimidine‐5,7‐diones 1 were prepared and examined for in vivo antiprotozoan activity to study structure‐activity relationships that might lead us to more active derivatives. Mesoionic compounds 1A and 1B were inoculated into Swiss Webster male mice with Trypanosoma musculi infection. the effects were measured by studying parasite populations during the course of patent period (days 9 through 15 post‐infection).

The injection of 200 μg of compound 1A along with 5 times 104 trypanosomes affected the level of parasitemia at both the peak and during days 9 to 13 post infection. Experimental animals that received drug 1A prior to and after infection with T. musculi developed significantly lower parasitemia as compared to the control animals at the height of parasite populations (day 11 of observation). the group that received the drug simultaneously with trypanosome infection had significantly lower parasitemias on day 11 and 13 of infection compared to the controls.
In Vitro Induced Anaerobic Resistance to Metronidazole In Trichomonas Vaginalis
Authors: KULDA JAROSLAV , TACHEZY JAN , ĈERKASOVOVA APOLENA
Published: May 2007

ABSTRACT. Resitance to metronidazole detectable under anaerobic conditions was induced in two Trichomonas vaginalis strains (TV 10‐02 and MRP‐2) by cultivation at gradually increasing pressure of the drug (1‐100 μ/ml) for 12 to 21 months. the resistant derivatives reproduced in anaerobic trypticase‐yeast‐extract‐maltose medium at 100 μ/ml metronidazole and showed very high values of minimal lethal concentration for metronidazole in anaerobic in vitro assays (556‐1,600 μ/ml at 48‐h exposure to the drug). Stepwise selection was necessary to develop the resistance in either strain. Attempts to induce resistance by prolonged maintenance of trichomonads with constant, low or moderate drug concentrations (3‐10 μ/ml) were unsuccessful. Freshly developed resistance to high concentrations of metronidazole was unstable in absence of drug pressure as well as after cryopreservation. Development of stable resistance required further cultivation at 100 μ/ml metronidazole. Unstable substrains did not revert to original susceptibility. They retained a moderate level of resistance, being able to grow at 10 μ/ml metronidazole. the strains with fully developed resistance had no activity of the hydrogenosomal enzymes pyruvate: ferredoxin oxidoreductase and hydrogenase and ceased uptake of [14C]‐metronidazole. These findings indicate that the pyruvate oxidizing pathway responsible for metronidazole activation was inactivated and metabolism of the drug stopped.
Low Genetic Diversity In Willaertia Magna From Wide Geographical Sources, and Characterisation of Willaertia Minor N. Sp. (Heterolobosea, Vahlkampfidae)
Authors: DOBSON PHILIP J. , ROBINSON BRET S. , CHRISTY PETER , HAYES SUZANNE J.
Published: May 2007

ABSTRACT. Twelve isolates assigned to Willaertia magna by morphological and physiological criteria, including the type material, were characterised at 23 enzyme‐encoding loci. Isolates from Australia, Bangladesh, Belgium, England, France, Indonesia, Japan, Korea, Madagascar and Papua New Guinea showed fixed alleles at 18 loci and polymorphism at Acp, Lap, Me, 6Pgd and Pgm 1. the maximum difference in pairwise comparisons was 8.7%, consistent with intra‐specific variation in the related genus Naegleria. an additional isolate, assigned to Willaertia by features of its flagellate and cyst stages, represents a new species. Willaertia minor n. sp. shares alleles with W. magna at only three loci, has a maximum growth temperature of 38°C and is significantly smaller in all stages than W. magna. Flagellates appear to divide only once and fail to replace the lost flagella, producing biflagellate daughter cells. Cysts and trophozoites are more readily mistaken for Naegleria, but lack perinuclear granules, as do the mature cysts of W. magna.
Characterization of Kinetoplast DNA from Phytomonas serpens
Authors: SÁ‐CARVALHO DANIEL , PEREZ‐MORGA DAVID , TRAUB‐CSEKO YARA M.
Published: May 2007

ABSTRACT. The restriction enzyme digestion of kinetoplast DNA from four Phytomonas serpens isolates shows an overall similar band pattern. One minicircle from isolate 30T was cloned and sequenced, showing low levels of homology but the same general features and organization as described for minicircles of other trypanosomatids. Extensive regions of the minicircle are composed by G and T on the H strand. These regions are very repetitive and similar to regions in a minicircle of Crithidia oncopelti and to telomeric sequences of Saccharomyces cerevisiae. Conserved Sequence Block 3, present in all trypanosomatids, is one nucleotide different from the consensus in P. serpens and provides a basis to differentiate P. serpens from other trypanosomatids. Electron microscopy of kinetoplast DNA evidenced a network with organization similar to other trypanosomatids and the measurement of minicircles confirmed the size of about 1.45 kb of the sequenced minicircle.
Lipophosphoglycan Antigen Shedding By Leishmania Donovani
Authors: KANESHIRO EDNA S. , WYDER MICHAEL A.
Published: May 2007

ABSTRACT. The biochemical characterizations of lipophosphoglycans from various Leishmania species reported by other workers may or may not contain several types of lipophosphoglycan molecules. This is the first report in which a specific lipophosphoglycan has been defined by both its antigenie and electrophoretic properties. Furthermore, a purification procedure for this specific lipophosphoglycan is described and some biochemical characterizations are presented. Phospholipase C and the so‐called phosphatidylinositol‐specific phospholipase C of Bacillus cereus convert the amphipathic form of the lipophosphoglycan antigen to the hydrophilic form. Under equivalent incubation conditions, other phospholipases tested were not effective in conversion of the amphipathic to the hydrophilic form. Since the amphipathic form is present in conditioned media, antigen shedding cannot be explained by phospholipase C digestion of the amphipathic form, which would result in the release of only the hydrophilic form into the medium. Both the pellet and the supernatant fractions of conditioned media contained both forms of the antigen and did not differ in the relative amounts of the two. This observation rules out membrane blebbing as the major mechanism for the release of the amphipathic form.
A Redescription of Entamoeba Histolytica Schaudinn, 1903 (Emended Walker, 1911) Separating It From Entamoeba Dispar Brumpt, 19251
Authors: DIAMOND LOUIS S. , CLARK C. GRAHAM
Published: May 2007

ABSTRACT. Explaining the low incidence of invasive disease (10%) in humans infected with Entamoeba histolytica has occupied the attention of generations of both clinical and nonclinical investigators. One possible explanation would be the existence of two morphologically identical species—one an invasive pathogen, the other noninvasive. This was first proposed by Brumpt in 1925, but his explanation was virtually ignored until 1978 when the first of several publications appeared suggesting that E. histolytica did indeed consist of two species. We have reexamined Brumpt's claim in light of recent biochemical, immunological and genetic studies and conclude that the data derived from these investigations provide unequivocal evidence supporting his hypothesis. With this in mind, we redescribe the invasive parasite retaining the name Entamoeba histolytica Schaudinn, 1903 (Emended Walker, 1911), and set it apart from the noninvasive parasite described by Brumpt, Entamoeba dispar Brumpt, 1925.
“On A Piece of Chalk”‐Updated1
Authors: LEE DR. JOHN
Published: May 2007

ABSTRACT.Many advances have been made in our knowledge of the biology of foraminifera over the past several decades. Fine structural, biophysical, and molecular biological studies have shown that the most prominent components of their distinctive bidirectional granuloreliculopods are bundles of micro tubules linked by crossbridges to each other, as well as to membrane‐bound organelles and the plasma membrane. the microtubules ratchet past each other as dynein transduces the free energy of ATP to produce pseudopodal movements. In spite of the fact that there are over 40,000 described species of living and fossil species of foraminifera, there have been many recent exciting discoveries of new species and groups. New casting techniques are providing us with greater understanding of the complexities and functional aspects of form in the group. Significant advances are being made in understanding the distribution and energetics of deep‐sea forms. Larger and planktonic foraminifera are the hosts for a particularly diverse range of endosymbiotic algae, including dinoflagellates, chlorophytes, unicellular rhodophytes, and diatoms. Chloroplast husbandry also occurs. Significant research effort has been expended yielding us considerable insight into various aspects of the endosymbiotic phenomenon. A unified conceptual framework has been drawn to help us understand the life cycle options found in foraminifera.
Phylogeny of Trichomonads Based On Partial Sequences of Large Subunit Rrna and On Cladistic Analysis of Morphological Data
Authors: VISCOGLIOSI ERIC , PHILIPPE HERVE , BAROIN ANNE , PERASSO ROLAND , BRUGEROLLE GUY
Published: May 2007

ABSTRACT. Several domains of large subunit rRNA from nine trichomonad species have been sequenced. Molecular phylogenies obtained with parsimony and distance methods demonstrate the trichomonads are a monophyletic group which branches very early in the eukaryotic tree. the topology of the trees is in general agreement with traditional views on evolutionary and systematic relationships of trichomonads. A clear dichotomy is noted between the subfamily Trichomonadinae and the subfamily Tritrichomonadinae. In the latter subfamily, a second division separates the “Tritrichomonas muris‐type” species from the “Tritrichomonas augusta‐type” ones. Previous evolutionary schemes in which the Monocercomonadidae were regarded as the most “primitive” and the Trichomonadidae as more “evolved” are not in agreement with our molecular data. the emergence of Monocercomonas and Hypotrichomonas at the base of the Tritrichomonas lineage suggests a secondary loss of some cytoskeletal structures, the costa and undulating membrane in these genera. This is corroborated by the early branching position of Trichomitus. which possesses a costa and an undulating membrane and has usually been placed among the Trichomonadidae on the basis of cytological characters. A cladistic analysis was applied to the available morphological characters in order to produce a hierarchical grouping of the taxa reflecting their morphological diversity. Supplementary key words. Evolution, molecular phylogeny, morphological cladistic analysis.
Inhibition of Dna Synthesis In the Macronuclear Replication Band of Euplotes Eurystomus
Authors: OLINS DONALD E. , OLINS ADA L.
Published: May 2007

ABSTRACT. The replication band is a large, migrating, macronuclear domain that is the site of DNA synthesis in hypotrichous ciliated protozoa. A number of agents that produce inactivation of this structure and its replicational activity are described here. These agents include heat shock, aphidicolin, cell crowding, various cAMP phosphodiesterase inhibitors and a calmodulin inhibitor. With the exception of aphidicolin, which has a direct inhibitory effect upon DNA polymerases, the mechanisms of inactivation are presently unknown. the inactivating properties of cAMP phosphodiesterase inhibitors suggest that intracellular cAMP levels may influence replication band structure and function.
Isospora Normanlevinei N. Sp. and Isospora Coluzzii N. Sp. (Apicomplexa: Eimeriidae) In Emberiza Cirlus (Cirl Bunting) (Passeriformes‐Emberizidae)
Authors: CRINGOLI GIUSEPPE , QUESADA ANTONIO , CAPUANO FEDERCO
Published: May 2007

ABSTRACT. The morphological characteristics of two new species of Isospora observed in Emberiza cirlus (Cirl Bunting) from Italy are reported. the oocysts of Isospora normanlevinei n. sp. are spherical or sub‐spherical, with a smooth double‐layered wall, and measure 24.2 times 23.7 (21.0‐26.5 times 21.5‐25.5) μm; each oocyst contains 2 to 10 polar granules. No micropyle or residuum was observed. the piriform sporocysts measure 19.4 times 11.2 (17.0‐21.0 times 10.0‐12.5) μm and contain a dispersed residuum. the Stieda body is flat; the substiedal body, with scattered clear and dark granules, may be either symmetrical or asymmetrical. the oocysts of I. coluzzii n. sp. are asymmetrical and rounded shape and measure 28.6 times 24.2 (25.0‐31.5 times 21.5‐26.0) μm. the oocyst has a double‐layered wall and 2 to 3 polar granules. Neither micropyle nor residuum is present. the sub‐ellipsoidal sporocyst, measuring 18.2 times 10.0(16.5‐20.0 times 9.0‐11.0) μm, has a dispersed sporocyst residuum. the Stieda complex is symmetrical.
Rumen Ciliate Protozoa of the Blue Duiker (Cephalophus monticola), with Observations on Morphological Variation Lines Within the Species Entodinium dubardi
Authors: DEHORITY BURK A.
Published: May 2007

ABSTRACT. Protozoal concentrations were determined in rumen and cecal contents of 20 blue duikers (Cephalophus monticola). Ten animals of each sex were fed either a high concentrate or high roughage diet. Rumen protozoa were present in 19 of the 20 animals and concentrations ranged from 4.5 to 33.7 × 106 per g of rumen contents. At the higher concentrations, protozoal cells equaled between 30–40% of the total rumen contents volume. No protozoa were found in cecal contents. Weight of rumen contents was higher in females than in males (P < 0.01), and rumen protozoa concentrations were higher in males (P < 0.05) and in those animals fed the high concentrate diet (P < 0.05). All the protozoa were identified as belonging to a single species, Entodinium dubardi. However, an average of about 30% of the E. dubardi cells varied from the typical morphology of this species. These cells appeared to be on variation lines leading toward 7–10 other non‐caudate species of Entodinium. The present data were used to evaluate and discuss the concept of variation lines within E. dubardi.
Fine Structure of the Marine Amoeba Vexillifera telmathalassa Collected from a Coastal Site Near Barbados with a Description of Salinity Tolerance, Feeding Behavior and Prey
Authors: ANDERSON O. ROGER
Published: May 2007

ABSTRACT. Amoebae cultured from seawater collected at a coastal site near Barbados were largely a lobose amoeba with long tapered subpseudopodia identified as Vexillifera telmathalassa. Vexillifera telmathalassa occurs widely in marine environments and additional information is presented here on its fine structure, salinity tolerance, and feeding behavior toward clarification of its taxonomic characteristics and ecological niche. The amoebae were able to adjust to a gradual decline in salinity from 36‰ to 16‰, but at a salinity of 12‰. They all became immobilized and discoidal. The fine structure showed a centrally located nucleus (2.1 μm) with a prominent nucleolus. The plasma membrane is coated with glycostyles 17 nm long and 14 nm apart, and may be derived from secretory vesicles with similar glycocalyx lining. Bacteria and occasional eukaryotic remains occur in digestive vacuoles or membrane‐enclosed spaces. Some vacuoles (2.0–2.5 μm) are filled with scattered masses of digested material and resemble the “glanzkörper” previously identified by light microscopy. In addition to bacterial prey, microflagellates were also ingested in laboratory culture as observed by light microscopy. Vexillifera telmathalassa may be more closely linked trophically to the microbial loop than previously recognized.
Conversion of Intrasporal Trehalose into Reducing Sugars During Germination of Nosema algerae (Protista: Microspora) Spores: A Quantitative Study
Authors: UNDEEN ALBERT H. , MEER ROBERT K. VANDER
Published: May 2007

ABSTRACT. Carbohydrates were extracted from dormant, stimulated and germinated spores of Nosema algerae. Concentrations of total sugars were measured by the Anthrone test. Non‐reducing sugars were quantified by NaOH hydrolysis followed by the Anthrone reaction, and reducing sugars by the Nelson's test. Glucose was measured by the o‐toluidine test and a glucose oxidase assay. The concentrations of trehalose in the cytoplasm of the dormant, ungerminated spore was estimated to be in excess of 1.0 M. Trehalose decreased by 70% during the five‐minute course of germination. All of the lost trehalose was converted to reducing sugar of which 70–78% was glucose. The osmotic potential increase caused by catabolism of trehalose appears to be sufficient for germination.
Effects of Host Cell Density on Cell Infection Level in Antheraea eucalypti (Lepidoptera: Saturniidae) Cell Cultures Persistently Infected with Nosema bombycis (Microsporida: Nosematidae)
Authors: YASUNAGA CHISA , FUNAKOSHI MASAKO , KAWARABATA TAKESHI
Published: May 2007

ABSTRACT. Spores of Nosema bombycis Y9101, isolated from the beet armyworm, Spodoptera exigua, were primed with an alkaline solution and inoculated into Antheraea eucalypti cell cultures. Infected cells were subcultured every five days at three cell densities (2.5 × 103, 5.0 × 103, and 1.0 × 104 cells/cm2). A difference was observed in the spread of N. bombycis Y9101 infection between low‐density and higher‐density cultures of host cells. The host cell density did not affect the productivity of secondary infective forms of the parasite. The principal factor determining the rate of microsporidian infection in vitro was the number of host cells existing within the reach of extruded short‐coiled polar tubes from spores germinated intracellularly.
The α‐ and β‐Tubulin Genes of Euplotes octocarinatus
Authors: LIANG AIHUA , SCHMIDT HELMUT J. , HECKMANN KLAUS
Published: May 2007

ABSTRACT. The α‐ and the β‐tubulin genes of the hypotrichous ciliate Euplotes octocarinatus were isolated from a size‐selected macronuclear DNA library. The α‐tubulin gene is located on a 1,587 bp macronuclear DNA molecule and the β‐tubulin gene on a 1,524 bp macronuclear DNA molecule. Sequencing revealed that all the cysteine residues of the two genes are encoded by the common cysteine codons UGU and UGC and none by an UGA codon. This is in contrast to the genes of E. octocarinatus sequenced so far, where some of the cysteines are encoded by the opal codon UGA. The tubulin genes end like other Euplotes genes with a TAA. They do not contain introns. The last codon for an amino acid in the α‐tubulin gene is a GAA which codes for glutamic acid. This is in contrast to what has been reported for most α‐tubulin genes, but it supports findings for other hypotrichous ciliates. No evidence for the existence of more than one type of α‐ and one type of β‐tubulin genes could be obtained.
The Different Behavior of Diphtheria Toxin, Modeccin and Ricin in HeLa Cells Infected with Trypanosoma cruzi
Authors: OSUNA ANTONIO , RODRIGUEZ‐CABEZAS NIEVES , GAMARRO FRANCISCO , MASCARO CARMEN
Published: May 2007

ABSTRACT. We have studied the action of diphtheria toxin, modeccin and ricin on HeLa cells infected by Trypanosoma cruzi. Parasitized HeLa cells were resistant to diphtheria toxin and modeccin, whereas non‐parasitized cells from the same cultures and control cultures showed cytopathological alterations. Protein synthesis, assayed by the incorporation of labelled methionine, diminished in toxin‐treated control cultures but remained unaltered in the infected ones, compared to synthesis by untreated infected cells. Ricin, on the other hand, is a toxin that enters the cytoplasm by endocytosis. It has greater cytopathological effects in parasitized cells than in non‐parasitized ones from the same cultures or uninfected control cells. Protein synthesis was inhibited in infected cultures treated with ricin.
Description of a New Species of Microsporidia from Muscidifurax raptor (Hymenoptera: Pteromalidae), a Pupal Parasitoid of Muscoid Flies
Authors: BECNEL JAMES J. , GEDEN CHRISTOPHER J.
Published: May 2007

ABSTRACT. A microsporidian parasite, Nosema muscidifuracis n. sp., has been found in Muscidifurax raptor, a parasitoid of muscoid flies. Stages of the parasite developed in direct contact with the host cell cytoplasm and were detected in midgut epithelium, Malpighian tubules, ovaries (including oocytes) and fat body of larvae and adults. Spores were also detected within eggs deposited on the host. Light and electron microscopy revealed a developmental cycle with diplokaryotic stages dividing by binary fission and disporous sporulation sequences producing diplokaryotic spores of three morphological classes, differing significantly only in length of the polar filament. Two of the classes were found in larvae, pupae and adults. One of these, with about five turns in the coiled polar filament, is presumed to be responsible for transmission from cell to cell within the host (autoinfection) and the other, with about 10 turns, responsible for transmission from host to host. A third class, with about 15 turns in the polar filament, was found in eggs of M. raptor. It is, presumably, either involved in initiation and spread of the infection at eclosion or is responsible for horizontal transmission to a new host individual when eggs are cannibalized.
Transmission of Surface Pattern Through a Dedifferentiated Stage in the Ciliate Paraurostyla. Evidence from the Analysis of Microtubule and Basal Body Deployment
Authors: FLEURY ANNE , LAURENT MICHEL
Published: May 2007

ABSTRACT. During conjugation of the hypotrich ciliate Paraurostyla weissei, the two partners fuse to form a transient dedifferentiated stage, the zygocyst, which later redifferentiates into a vegetative cell. Immunocytochemical studies have been performed to follow the deployment of microtubules and basal bodies during the entire cycle of conjugation. They show that a superficial lattice persists during the whole zygocyst stage, after most of the infraciliature of the exconjugants has been disassembled. These superficial microtubules display different immunocytochemical properties in the mature zygocyst and during its morphogenesis, suggesting that some transient chemical modifications of the microtubules are associated with the morphogenetic activity. In the zygocyst, the superficial microtubules retain the specific orientation characteristic of the ventral and the dorsal sides of the recipient cell, respectively. In the course of subsequent morphogenesis of the zygocyst, these specific cellular territories differentiate into the ventral and dorsal sides of the new cell. Although our experiments do not resolve the question of whether superficial microtubules play an active or merely a passive role in the transmission of surface pattern, they show that no complete breakdown in cell polarity occurs, even through a profound dedifferentiated stage. Thus, the overall surface pattern appears to be retained, in a simplified form, through the conjugation cycle.
A Tandem Repeat of Rat‐derived Pneumocystis carinii Genes Encoding the Major Surface Glycoprotein
Authors: SUNKIN SUSAN M. , STRINGER SAUNDRA L. , STRINGER JAMES R.
Published: May 2007

ABSTRACT. A fragment from the genome of rat‐derived Pneumocystis carinii was found to contain two MSG genes arranged as a direct repeat. The sequences from one gene (MSG B), the region between the two genes, and part of the second gene (MSG A) were determined. The two MSG genes were not identical in sequence. The open reading frames of MSG A and MSG B encode non‐identical proteins, both of which are similar to that encoded by a previously published cDNA. The MSG B gene sequence showed no evidence of introns. The 5’and 3’untranslated regions of the MSG gene pair were highly conserved, but the regions immediately upstream of the open reading frames of MSG A and B were different from the region upstream of a previously characterized MSG cDNA. Primers designed to extend upstream of the 5’end of MSG and downstream of the 3’end of MSG were used in a polymerase chain reaction with total genomic P. carinii DNA as template. Presumptive intergenic amplification products from this reaction were cloned and sequenced. The sequences of these regions were similar but distinct, indicating that tandem arrangement of MSG genes is a common organizational motif.
Subcellular Localization of the Enzymes of the Arginine Dihydrolase Pathway in Trichomonas vaginalis and Tritrichomonas foetus
Authors: YARLETT NIGEL , LINDMARK DONALD G. , GOLDBERG BURT , ALI MOHARRAMI M. , BACCHI CYRUS J.
Published: May 2007

The enzymes of the arginine dihydrolase pathway were demonstrated in Tritrichomonas foetus and their subcellular localization determined for both T. foetus and Trichomonas vaginalis. Ornithine carbamyltransferase (anabolic and catabolic activities), ornithine decarboxylase and carbamate kinase activity were localized predominately (56–80%) in the non sedimentable fraction of both species. A large proportion (35–40%) of the arginine deiminase was, however, recovered in the large granular fraction, and this distribution was unchanged by increasing the ionic strength of the buffer. Upon density gradient centrifugation the particles containing arginine deiminase activity had an isopycnic density of 1.09 g/ml in percoll, and separated from hydrogenosomes (1.18 g/ml) and lysosomes (1.12 g/ml). Arginine deiminase was also the only enzyme of the dihydrolase pathway which demonstrated latency upon treatment of the 1.09 g/ml fraction with non‐ionic detergents. The results demonstrate the presence of the arginine dihydrolase pathway in T. foetus and indicate that at least a portion of the arginine deiminase in trichomonads is membrane associated.
Occurrence of the Parasitic Dinoflagellate Amoebophrya ceratii in Chesapeake Bay Populations of Gymnodinium sanguineum
Authors: COATS D. WAYNE , BOCKSTAHLER KATRIN R.
Published: May 2007

Chesapeake Bay populations of the red‐tide dinoflagellate Gymnodinium sanguineum were regularly infected by the parasitic dinoflagellate Amoebophrya ceratii during the summers of 1988–1991. Infections developed inside the nucleus of G. sanguineum and were always lethal to the host. Parasite generation time was ˜ 40 h at 23° C, with the intracellular, trophont phase lasting 39.5 ± 0.3 h, and the extracellular, vermiform stage persisting for ˜ 20 min. Near surface accumulations of G. sanguineum sometimes exceeded 1,000 cells/ml; however, host abundance was relatively low when integrated over the surface mixed layer of each station (mean = 12.2 cells/ml ± 2.96 SE; n = 60). Parasitized hosts were encountered in 75% of the samples where host abundance was ≥ 1 per ml, and epidemic outbreaks (20–40% hosts infected) were observed on several occasions. Epidemic infections were generally located several meters below surface accumulations of G. sanguineum and were always restricted to a narrow region near the pycnocline. Consequently, integrated station values for parasite prevalence were low, with an average 2.7% (± 0.31 SE; n = 60). Parasite induced mortality removed up to 8% of G. sanguineum populations per day, but averaged < 2% of host biomass throughout the Bay. Thus, parasitism by A. ceratii does not appear to be a major factor regulating G. sanguineum bloom in the main stem of Chesapeake Bay.
Modulation of Biological Functions of Naegleria fowleri Amoebae by Growth Medium
Authors: MARCIANO‐CABRAL FRANCINE , TONEY DENISE M.
Published: May 2007

Two strains of Naegleria fowleri amoebae were studied when the amoebae were maintained in the same growth medium or in two different media. A weakly pathogenic strain of N. fowleri, LEE, and a highly pathogenic strain, LEEmpCl, were compared for growth properties, the presence or absence of surface structures termed food cups, cytopathogenicity, cellular locomotion, susceptibility to complement‐mediated lysis and immunological relatedness by western immunoblot analysis when grown in Nelson medium or in Cline medium. The two different strains of N. fowleri, LEE and LEEmpCl, were more similar in protein profiles and functional activity when both strains were grown in the same nutritional medium. Differences in growth, proteins synthesized, cytopathogenicity, susceptibility to complement lysis and rate of locomotion were noted when the same strain was grown in different media. Naegleria fowleri grown in Cline medium demonstrated an increased rate of growth, an increase in its rate of locomotion, an increased resistance to complement lysis, and destroyed target nerve cells by contact‐dependent lysis. In contrast, the same strain of amoeba grown in Nelson medium showed slower growth, destroyed target cells by trogocytosis, and was less resistant to complement‐mediated lysis.
Membrane‐Associated Polysaccharides Composition, Nutritional Requirements and Cell Differentiation in Herpetomonas roitmani: Influence of the Endosymbiont
Authors: SILVA PAULO M. FARIA E , FIORINI JOÃO E. , SOARES MAURILIO J. , ALVIANO CELUTA S. , DE SOUZA WANDERLEY , ANGLUSTER JAYME
Published: May 2007

Herpetomonas roitmani, a trypanosomatid containing a bacterial endosymbiont, was cured by high doses of chloramphenicol. Wild‐type and cured flagellates were compared as to polysaccharide composition, nutritional requirements and cellular differentiation. Fucose (18.0%), xylose (15.7%), mannose (38.9%), galactose (10.8%), glucose (16.4%) and inositol (< 1.0%) were identified as polysaccharide components of cured H. roitmani as assessed by gas‐liquid chromatography. However, the wild‐type strain displayed a markedly different sugar profile, in that xylose was absent and inositol preferentially synthesized, whereas the other monosaccharide components remained unchanged. Variations in nutritional pattern also occurred between both strains. The bacterial endosymbiont seems to provide the flagellates with nutritional factors, including usual amino acids, vitamins, purine (as adenine) and hemin. The process of cell differentiation was also significantly influenced by the endosymbiont. Opisthomastigote forms predominate (72.0%) in cured as compared with wild‐type H. roitmani (37.0%).
Overcoating of Toxoplasma Parasitophorous Vacuoles with Host Cell Vimentin Type Intermediate Filaments
Authors: HALONEN SANDRA K. , WEIDNER EARL
Published: May 2007

The interaction between the Toxoplasma parasitophorous vacuole and vimentin‐type intermediate filaments in Vero cells was investigated via immunofluorescence microscopy. A significant rearrangement of host cell vimentin around the Toxoplasma parasitophorous vacuoles occurs throughout the course of infection. Host cell vimentin associates with the parasitophorous vacuoles within an hour after invasion. This vimentin overcoating of the vacuole is initiated at the host cell nuclear surface. During parasite multiplication, vimentin retains a closely defined association with the cytosolic surface of the parasitophorous vacuole. In addition, the vimentin intermediate filaments originating from the host cell nuclear surface are progressively rearranged around the enlarging parasitophorous compartment. During infections, the order of vimentin cytoskeleton is normal throughout the cell and appears redefined only at the vicinity of the parasitophorous vacuole. Depolymerization of the intermediate filaments was achieved with the phosphatase inhibitors okadaic acid and calyculin A. Disruption of the intermediate filament networks resulted in displacement of the parasitophorous vacuoles from the host cell nuclear surface. The data indicate that host cell vimentin binds to the Toxoplasma parasitophorous vacuoles and that the host intermediate filament network serves to dock the parasite compartment to the host cell nuclear surface.
Monovalent Cations Induce Microsporidian Spore Germination In Vitro
Authors: FRIXIONE EUGENIO , RUIZ LOURDES , UNDEEN ALBERT H.
Published: May 2007

ABSTRACT The relative capacity of Na+, K+ and Cl‐ to stimulate germination of spores of the microsporidian Nosema algerae, a pathogen of mosquitoes, was examined by ion substitution experiments. Sodium at 0.1 M was ineffective to produce the high percentage of germination that typically occurs with 0.1 M NaCl (the normal stimulation solution) if Cl‐ was substituted with the usually impermeant anions SO42‐, HPO42‐, or the organic acids oxalate, cacodylate, EGTA, MES and HEPES. However, substantial concentration‐ and pH‐dependent germination was seen with Na2SO4 in the 0.2‐0.8 M Na+ range. Similar results were obtained with solutions of K+ accompanied by impermeant anions. In contrast, the chloride salts of usually impermeant cations, like choline and triethanolamine, failed to germinate spores even at 0.8 M unless Na+ or K+ was independently added. The presence of 0.5 M choline chloride in the medium reduced the levels of Na2SO4 required to produce germination down to equivalence with those of Na+ in the normal stimulation solution. Monensin, a Na+ ionophore, facilitated the germination induced by a medium‐level stimulus (0.04 M NaCl) in sonicated samples. These findings indicate that N. algerae spores germinate in response to the alkali metal cations, while CI‐ plays a passive role by diffusing to maintain internal electroneutrality during cation influx. A possible mechanism of cation action in spore germination is suggested on the basis of these results and observations on other systems of intracellular motility.
Tubulin Genes in the Algal Protist Euglena gracilis
Authors: LEVASSEUR PIERRE J. , MENG QI , BOUCK G. BENJAMIN
Published: May 2007

ABSTRACT Alpha‐ and beta‐tubulin cDNA were selected from a Euglenaλgt11 expression library, recloned and either sequenced (α‐tubulin cDNA) or hybridized to Euglena RNA and DNA (α‐ and β‐tubulin cDNA). RNA for hybridization was extracted at 30 minute intervals after flagellar amputation and quantitated for cDNA binding. Unlike previous reports on most other flagellates, no net increase in either α‐ or β‐tubulin RNA could be detected during regeneration—suggesting steady state or constitutive tubulin RNA synthesis. Incubation of the cDNA with genomic DNA after restriction digestion produced patterns of hybridization consistent with the presence of one to two kinds each of the α‐ and β‐tubulin genes. The deduced amino acid sequence of the α‐tubulin cDNA was more than 90% identical to the α‐tubulins of Trypanosoma, Chlamydomonas, Naegleria, Tetrahymena and higher plants. The carboxy terminus of the α‐tubulin cDNA and the previously sequenced β‐tubulin of Euglena showed greatest identity to the carboxy terminus of the tubulins from Trypanosoma brucei. The sequence data for α and β‐tubulins of Euglena provides direct evidence for the similarity of two gene products from euglenas and trypanosomes and adds support to earlier suggestions that these organisms are phylogenetically related.
A New Marine Interstitial Ciliate from the Northwest Atlantic Coast Tracheloraphis primitarum Sp. N. (Ciliophora, Kinetofragminophora, Karyorelictida, Trachelocercidae)
Authors: EPSTEIN SLAVA S.
Published: May 2007

ABSTRACT A new species of marine interstitial ciliate, Tracheloraphis primitarum sp. n., is described from intertidal sands (160‐200‐μm medium grain size) along the Northwest Atlantic coast. Living specimens are not transparent under incident light, 0.4‐0.9 mm in length, and are characterized by an elongated body, bulbous anterior and rounded posterior regions. Cytostome is simple without a cleft on the lip. Protargol silver impregnation shows 18‐29 longitudinal kineties. The glabrous zone is very narrow, 6‐7 μm wide, and corresponds to the area occupied by one kinety and two interkinetal spaces. Ten to fifteen kineties terminate against the glabrous zone. Interkinetal extrusomes are present. The nuclear apparatus is a single centrally‐placed nuclear group that consists of three large irregular macronuclei and 2‐3 micronuclei; these are either clustered or encapsulated.