bluuebunny/crossref_metadata_2025 huggingface dataset:
A Light and Electron Microscopic Study of Trypanosoma fallisi N. Sp. in Toads (Bufo americanus) from Algonquin Park, Ontario
Authors: MARTIN DONALD S. , DESSER SHERWIN S.
Published: May 2007

Trypanosoma fallisi n. sp. is described from Bufo americanus in Ontario. The parasite was observed in 65 of 94 toads examined. The trypanosomes were pleomorphic with respect to the age of infections, being longer and broader in early infections (during spring and summer) and shorter and more slender during late summer and autumn. They ranged in size from 38–76 μm in body length and 3–8 μm in width, with a free flagellum 6–30 μm long. Epizootiological and experimental evidence suggests that this trypanosome is transmitted to the toads by the leech, Batracobdella picta. Trypanosoma fallisi is morphologically similar to T. bufophlebotomi described in Bufo boreas from California, but geographic isolation, host and vector differences as well as slight morphological differences indicate that speciation has occurred. Similar trypanosomes from Bufo americanus (which were identified as T. bufophlebotomi) in Michigan, are probably T. fallisi. This species shares many ultrastructual features with trypanosomes of other lower vertebrates and also of mammals.
Ultrastructural Studies on the Trypanosomatid Phytomonas serpens in the Salivary Glands of a Phytophagous Hemipteran
Authors: FREYMULLER EDNA , MILDER REGINA , JANKEVICIUS J. V. , JANKEVICIUS SHIDUCA I. , CAMARGO E. PLESSMANN
Published: May 2007

Electron microscopy of salivary glands of the phytophagous hemipteran Phihia picta infected with Phytomonas serpens revealed the presence of flagellates in the gland periphery beneath the gland envelope, in the gland central lumen, between gland cells in the intercellular space and inside the gland cells. In the latter case, flagellates were found in the cytoplasm whether or not it was surrounded by a vacuolar membrane. Flagellates were always of the promastigote type, sometimes displaying a large twisted body. Morphological peculiarities of flagellates in different gland locations are recorded.
Genome Structure and Evolution of Naegleria and its Relatives
Authors: CLARK C. GRAHAM
Published: May 2007

In the 4 yr since the molecular biology of DNA in Naegleria was last reviewed several major advances have been made, and these are reviewed here: isolation and characterization of mitochondrial and ribosomal DNAs; enumeration of chromosomal DNAs by pulsed field gel electrophoresis; sequence analysis of differentially expressed genes; phylogenetic placement of the genus Naegleria among the eukarayotes and Naegleria species within the genus.
Epidemiology of Free‐Living Ameba Infections1
Authors: VISVESVARA GOVINDA S. , STEHR‐GREEN JEANETTE K.
Published: May 2007

Small free‐living amebas belonging to the genera Acanthamoeba and Naegleria occur world‐wide. They have been isolated from a variety of habitats including fresh water, thermal discharges of power plants, soil, sewage and also from the nose and throats of patients with respiratory illness as well as healthy persons. Although the true incidence of human infections with these amebas is not known, it is believed that as many as 200 cases of central nervous system infections due to these amebas have occurred world‐wide. A majority (144) of these cases have been due to Naegleria fowleri which causes an acute, fulminating disease, primary amebic meningoencephalitis. The remaining 56 cases have been reported as due either to Acanthamoeba or some other free‐living ameba which causes a subacute and/or chronic infection called granulomatous amebic encephalitis (GAE). Acanthamoeba, in addition to causing GAE, also causes nonfatal, but nevertheless painful, vision‐threatening infections of the human cornea, Acanthamoeba keratitis. Infections due to Acanthamoeba have also been reported in a variety of animals. These observations, together with the fact that Acanthamoeba spp., Naegleria fowleri, and Hartmannella sp. can harbor pathogenic microorganisms such as Legionella and or mycobacteria indicate the public health importance of these amebas.
Effect of Gossypol on Trypomastigotes and Amastigotes of Trypanosoma cruzi
Authors: ROVAI LEONOR E. , AOKI AGUSTIN , BURGOS NELIA M. GEREZ DE , BLANCO ANTONCO
Published: May 2007

Bloodstream Trypanosoma cruzi trypomastigotes isolated from infected mice undergo reduction of motility and structural damages after 5 to 45 min exposure to gossypol at concentrations ranging from 5 to 50 μM. When 1% serum albumin is added to the incubation medium, no alterations of parasites are observed, even with 100 μM gossypol. Intracellular T. cruzi amastigotes in infected Vero cell cultures exposed to 5 μM gossypol for 2 h do not show changes. Incubation with 5 μM gossypol for 48 h produces complete disruption of host cells; however, the amastigotes they contain show only mineor alterations. The observations indicate that, in protein‐rich media, gossypol is complexed into associations which have no activity on the different forms of the T. cruzi biological cycle.
Electrophoretic Karyotype and Linkage Groups of the Amoeboflagellate Naegleria gruberi
Authors: CLARK C. GRAHAM , LAI ELAINE Y. , FULTON CHANDLER , CROSS GEORGE A. M.
Published: May 2007

ABSTRACT. We have constructed a molecular karyotype for two strains of Naegleria gruberi using pulsed field gel electrophoresis. Each strain has about 23 chromosomes, considerably more than any previous estimate. These chromosomes range in size from 400 kilobasepairs to over 2,000 kilobasepairs. In Naegleria, construction of the DNA karyotype depends on assessment of the anomalous electrophoretic mobility of the circular ribosomal RNA genes. We have determined the chromosomal locations of an identified unique gene (flagellar calmodulin) and four identified multigene families (α‐ and β‐tubulin, actin, ubiquitin), as well as three differentially expressed genes of unknown functions. The ca. 12 actin genes are dispersed over at least seven chromosomes, whereas the majority of the more than eight α‐tubulin genes are confined to a single chromosome. The ubiquitin genes are found on five chromosomes in one strain and seven in the other and the β‐tubulin genes are on three or four. Our observations provide a foundation for molecular genetic studies in this organism.
Non‐Mendelian Inheritance of Early Maturity in Euplotes crassus
Authors: DINI FERNANDO , BLEYMAN LEA K. , GIUBBILINI PAOLA
Published: May 2007

ABSTRACT. This paper reports on a new phenomenon in the ciliated protists: cytoplasmically determined early sexual maturity. Stock MN1 of the marine hypotrich Euplotes crassus matures immediately after conjugation. We analyzed the respective contribuboas of the nucleus and the cytoplasm to the inheritance of this stable condition. A genetic marker, and new methods in E. crassus for cytoplasmic labeling, production of amicronucleates, and induction of selfing were used. Crosses within and among the early mature (EM) variants and late mature (LM) “wild type” lines were done in ovarious combinations. Descendants of EM conjugants continued to be EM, and descendants of LM continued to be LM, regardless of the different experimental approaches used. The results of the crosses clearly show that the clonally stable, variant EM phenotype is transmitted at conjugation in a non‐Mendelian manner through the cytoplasmic lineage. The expression of the trait is independent of the micronuclear genome, but the precise site and nature of the hereditary basis is unknown.
Growth of Phytomonas serpens in a Defined Medium; Nutritional Requirements
Authors: DA SILVA JOÃO BATISTA TAVARES , ROITMAN ISAAC
Published: May 2007

ABSTRACT. Three strains of Phytomonas serpens two from tomatoes, Lycopersicon esculentum one from the insect Phtia picta (Hemiptera, Coreidae), were cultivated in a chemically defined medium developed from a defined medium for cultivating insect flagellates. Besides organic growth factors required by other insect trypanosomatids this flagellate requires, serine and inositol. Glutamine stimulates growth, and, surprisingly, does not require heme.
The Role of Osmotic Pressure in the Germination of Nosema algerae Spores1
Authors: UNDEEN ALBERT H. , FRIXIONE EUGENIO
Published: May 2007

ABSTRACT. Both the lag period and the time required for the filament and sporoplasm to emerge from Nosema algerae spores were prolonged when germination occurred under hyperosmotic conditions. Polyethylene glycol (PEG) and sucrose inhibited germination, first by preventing eversion of the filament, and then at higher concentrations by preventing stimulation. The size of the spore cases decreased by about 21% following germination, indicating an elastic spore wall and turgor pressure in the dormant spores. Increased pressure during germination was indicated by less osmotically‐induced shrinkage in stimulated than in dormant spores and by higher concentration of solutes in the homogenates of germinated than ungerminated spores. These results are consistent with the hypothesis of a pressure increase during germination that is caused by an endogenous increase in solute concentration.
Morphological Drift Accompanying Nascent Population Differentiation in the Ciliate Euplotes vannus
Authors: GATES MICHAEL A.
Published: May 2007

A rare phenomenon can occur in ciliated protists of the genus Euplotes, which can undergo genetic recombination by the normal outbreeding process of conjugation following mild starvation. Occasionally, the dominant mutation for the autogamy trait arises. Individuals possessing the trait show obligate self‐fertilization upon mild starvation. This yields, after normal asexual division, a population of individuals that are reproductively isolated from the parental outbreeding strain. A morphometric analysis of sympatric autogamous and non‐autogamous populations of Euplotes vannus from Somalia demonstrates that there has been morphological drift in gross body proportions in the autogamous populations. However, the positional patterns of the locomotory organelles on the ventral surface remain unchanged. The changes in body proportions in the autogamous populations are relevant to the mechanics of the conjugation process, which involves fusion of the oral regions of paired cells belonging to complementary mating types.
Sphaerospora ictaluri N. Sp. (Myxosporea: Sphaerosphoridae) Observed in the Kidney of Channel Catfish, Ictalurus punctatus Rafinesque
Authors: HEDRICK R. P. , McDOWELL T. , GROFF J. M.
Published: May 2007

Sphaerospores were found in the kidneys of alevin channel catfish (Ictalurus punctatus) from a farm in Central California. MulticelluUr developmental stages, similar to C‐blood protozoans described for Sphaerospora spp. from cyprinid fishes, were observed in circulating blood and numerous tissues. Upon a 2nd examination of the same population offish 10 days later, sporogonic stages were seen developing into mature Sphaerospores in the lumina of the kidney tubules. Sporogeoesis was asynchronous with simple unicellular stages adjacent to more complex forms with developing polar capsules and valves. Only one elliptical spore (5.6 μm in width, 6.5 μm in thickness by 5.8 μm in length) developed within the surrounding pscudoplasmodium. Thin valves surrounded two sporoplasm cells and two subspherical polar capsules (1.7 × 1.9 μm) which contained a polar filament with four to five turns. The blood stages of the Sphaerospora sp. described here are similar to the trophozoites seen in channel catfish with proliferativc gill disease (PGD). Early stages of PGD also observed in the same population of channel catfish containing developmental and sporogonic stages of this newly recognized Sphaerospora sp. may suggest a causal relationship between this new myxosporean and the gill disease.
Intracellular Development of Enterocytozoon, A Unique Microsporidian Found in the Intestine of AIDS Patients
Authors: CALI ANN , OWEN ROBERT L.
Published: May 2007

Enterocytozoon was 1st described in 1985, in an AIDS patient with intestinal malabsorption and diarrhea. Since then, additional cases of infection with this organism have been observed, but only in individuals with AIDS and malabsorption. Intestinal tissue biopsies were obtained from a 45‐year‐old man prior to AIDS diagnosis, again nine months later and then at autopsy two months later. When the biopsies were examined electron microscopically, both sets contained the microsporidian parasite. However, the 2nd intestinal biopsy, when wasting was much more severe, contained infection in almost every small intestinal enterocyte examined. The parasite was actively developing, allowing us to detail its life cycle. The parasite is apansporoblastic, polysporous and has characteristics not previously reported in the Microsporida: (1) an electron lucent inclusion not usually seen in Microsporida is prominent and always present; (2) extremely elongated sausage‐shaped nuclei occur in the proliferative phase of parasite development; (3) the polar tube development uniquely involves the production of electron dense discs, yet results in the formation of a typical spore; and (4) polar tube development occurs prior to the final division of the multi‐nucleate sporont. On the basis of these characteristics, we are placing this genus in a new family, Enterocytozoonidae, n. fam.
Three‐Dimensional Reconstruction of Rabbit‐Derived Pneumocystis carinii from Serial‐Thin Sections I: Trophozoite
Authors: PALLUAULT FRANCOIS , PIETRZYK BRUNO , DEI‐CAS EDUARDO , SLOMIANNY CHRISTIAN , SOULEZ BENOIT , CAMUS DANIEL
Published: May 2007

The highly complex ultrastructural morphology of the endomembrane system in Pneumocystis carinii led us to perform three‐dimensional reconstruction from serial‐thin sections using the CATIA (Conception Assistée Tridimensionnelle Inter Active) Dassault system program. The three‐dimensional reconstruction of a small trophozoite made it possible to better understand the morphological relationship among organelles and to suggest cytophysiological hypotheses. By reconstructing other parasite stages, we gathered information about the evolution of organelles during the life cycle and about their physiology.
In Vitro Production of Lysine from 2,2′‐Diaminopimelic Acid by Rumen Protozoa
Authors: ONODERA RYOJI , TAKASHIMA HIDEMITSU , LING JOHN R.
Published: May 2007

Rumen protozoa can produce lysine from free 2,2′‐diaminopimelic acid (DAP). However, the quantitative importance of this transformation has been disputed; lysine contents of protozoal incubation supernatants reported by Onodera & Kandatsu [12] and Masson & Ling [9] show a 26‐fold difference. The in vitro experimental methods of both groups were compared to determine the causes of this difference. Lysine production was proportional to DAP concentration. Results with rumen protozoa from sheep or goats were similar. The incubation medium and deproteinizing procedure of the Welsh group gave a two‐fold increase in lysine production compared with Japanese protocols. Omissions of rice starch from protozoal incubations slightly increased lysine production, whereas omissions of antibacterial agents resulted in varying, yet relatively small changes. The greatest cause of the difference was the number of rumen protozoa incubated. When this factor was taken into account, the difference in the maximum rates of lysine production between the Welsh and Japanese groups was only three‐fold, namely 4.5 versus 15.0 nmol lysine/105 protozoa/h. Adding other amino acids to the incubations suggested that DAP uptake by rumen protozoa may occur via transport system ASC. The importance of DAP metabolism by protozoa as a source of lysine for ruminant host animals is discussed.
The Axenic Cultivation of Insect Forms of Trypanosoma (Duttonella) vivax and Development to the Infective Metacyclic Stage
Authors: GUMM IAN D.
Published: May 2007

A method for axenic cultivation of epimastigote and metacyclic forms of Trypanosoma (Duttonella) vivax at 27°C in vitro is described. Iscove's medium was supplemented with specific concentrations of foetal bovine serum, L‐proline, L‐glutamine, hypoxanthine, adenosine, pyruvate, and 2‐mercaptoethanol. Bloodstream form parasites rapidly transformed into epimastigote forms that grew as surface‐adherent colonies in plastic culture flasks. Transformation of epimastigotes to metacyclic forms was first observed 9–12 days after initiation of cultures. Percentages of metacyclics varied: East African T. vivax ranged up to 40% and West African T. vivax ranged up to 24%. Subcultures were made at two‐week intervals and maintained for several months. Transformation of bloodstream forms to epimastigotes depended on initial attachment to the bottom of culture flasks and the presence of L‐proline. The number and maturity of metacyclic forms was influenced by the concentrations of foetal bovine serum, L‐proline, L‐glutamine, and 2‐mercaptoethanol. Trypanosomes from cultures were cryopreserved, revived, and used to re‐establish fresh axenic cultures. These results represent a significant advance in cultivation of T. vivax insect forms that should enable studies to be accomplished on metabolism, differentiation, and pharmacology of this parasitic protozoan, free from the influence of extraneous cells.
The Effects of the Methylating Agent 1,2‐Bis(methylsulfonyl)‐1‐methylhydrazine on Morphology, DNA Content and Mitochondrial Function of Trypanosoma brucei Subspecies
Authors: PENKETH PHILIP G. , DIVO ALAN A. , SHYAM KRISHNAMURTHY , PATTON CURTIS L. , SARTORELLI ALAN C.
Published: May 2007

Repeated exposure of trypanosomes in vitro or in vivo to low concentrations of the methylating agent 1,2‐bis(methylsulfonyl)‐1‐methylhydrazine induces a series of moderately synchronous morphological and biochemical changes. Cell division halts and the long‐slender bloodstream forms transform to short‐stumpy forms via larger intermediate‐stage cells which contain approximately double the normal G2 content of DNA. In common with naturally occurring short‐stumpy trypanosomes, drug‐induced short‐stumpy forms do not infect rodents and when transferred to Cunningham's medium, transform to and replicate as procylics. Furthermore, these short‐stumpy forms exhibit α‐ketoglutarate supported motility and oxygen consumption, acquire the ability to reduce nitroblue tetrazolium (NADH diaphorase positivity) and appear to be in the G1 or G0 stage of the cell cycle based upon DNA content.
Physiological Reorganization and Post‐Traumatic Regeneration in Stylonychia mytilus: Reflections on Developmental Constraints and the Evolutionary Origin of Alternative Modes of Asexual Morphogenesis
Authors: ZOU SHI FA , NG STEPHEN F.
Published: May 2007

We investigated development of cortical ciliature in Stylonychia mytilus during starvation‐induced physiological reorganization, and during regeneration following amputation of the anterior part of the cell. Cortical reorganization in the two processes is generally similar. The posterior part of the adoral zone of membranelles is resorbed and replaced with newly assembled membranelles. The pre‐existing set of ventral cirri and dorsal bristles is entirely resorbed and replaced with new ones. Regenerants exhibit posterior displacement of the frontal‐ventral‐transverse cirri primordium and the undulating membrane primordium, and recruit basal bodies from ectopic locations for the development of these ciliature. This illustrates flexibility in the initiation site of ciliary primordia, and opportunism in utilizing building blocks. Such morphogenetic versatility of hypotrichs provides the basis for the operation of a global control of pattern formation, which governs cortical reorganization in dividers, and additionally, in the absence of the prerequisites for binary fission, alternative modes of cortical development such as physiological reorganization or regeneration. These considerations suggest that the three processes are homologous and that physiological reorganization and regeneration have evolved from binary fission. In physiological reorganization and regeneration, the micro‐ and macronuclei reorganize to resemble that in binary fission; these nuclear events are considered evolutionary relics of the nuclear development of binary fission. Tetrahymena also exhibits such morphogenetic flexibility; stomatogenesis is under global control, so that asexual cells can replace its oral apparatus without undergoing binary fission. Paramecium, on the other hand, adopts a more rigid strategy in relying heavily on pre‐existing structures for morphogenetic cues; this could have imposed constraints in the exploration of alternative modes of asexual development.
Anomalous Cases of Conjugation and Spontaneous Autogamy in Stylonychia mytilus: A Note on the Asexuality of Early Conjugants
Authors: ZOU SHI FA , NG STEPHEN F.
Published: May 2007

Four types of anomalous conjugation were documented in Stylonychia mytilus. Type I pairs were formed between mates of different sizes. These pairs exhibited an abnormal site of fusion in at least one of the mates, and the mates might face each other ventrally throughout conjugation instead of the normal side‐by‐side position. Type I pairs underwent sexual nuclear development and proceeded with the first cortical reorganization as in normal conjugants. Type II involved pairing at the anterior ends of mates with ventral surfaces facing the same direction. These pairs also underwent sexual nuclear development. Hence, aberrant orientation of the mates, and also ectopic sites of cytoplasmic fusion, if extensive, would permit sexual development. Type III pairs were united ventral‐to‐ventral with their anterior‐left sides at the adoral zone of membranelles, and remained as such throughout conjugation. In these pairs, nuclear and cortical events were typical of the asexual development of physiological reorganization. In Type IV pairs, one mate of the pair possessed a fission furrow and developed two sets of ciliature typical of binary fission, while the other mate might undergo physiological reorganization or binary fission. Type III and Type IV pairs thus reveal the asexual state of early conjugants, which can pursue either one of the two modes of asexual cortical reorganization; these cases reinforce the notion of overlap of asexual and sexual cycles during conjugation of hypotrichs. Spontaneous autogamy was documented for the first time for this genus. The autogamonts proceeded with nuclear development and with the first cortical reorganization. Some probably underwent second and third reorganizations, as in conjugants, but accompanied by abnormalities, particularly in the stages beyond fertilization. Post‐autogamous clones were nonviable except for one dubious case.
Phylogenetic Relationships of Blepharisma Americanum and Colpoda Inflata Within the Phylum Ciliophora Inferred From Complete Small Subunit Rrna Gene Sequences
Authors: GREENWOOD SPENCER J. , SCHLEGEL MARTIN , SOGIN MITCHELL L. , H.LYNN DENIS
Published: May 2007

ABSTRACT The complete small subunit rRNA gene sequences of the heterotrich Blepharisma americanum and the colpodid Colpoda inflata were determined to be 1719 and 1786 nucleotides respectively. the phylogeny produced by comparisons with other ciliates indicated that C. inflata is allied more closely with the nassophoreans and oligohymenophoreans than the spirotrichs. This is consistent with the placement of the colpodids in the Class Copodea. Blepharisma americanum was not grouped with the hypotrichs but instead was placed as the earliest branching ciliate. the distinct separation of B. americanum supports the elevation to class status given the heterotrichs based on morphological characters.
Morphology, Morphogenesis and Systematic Position of the Sorocarp Forming Ciliate Sorogena Stoianovitchae Bradbury & Olive, 1980
Authors: BARDELE CHRISTIAN F. , FOISSNER WILHELM , BLANTON RICHARD L.
Published: May 2007

ABSTRACT Reinvestigation of the type population of the sorocarp‐forming ciliate Sorogena stoianovitchae Bradbury & Olive, 1980 using the Fernández‐Galiano technique and various electron‐microscopy techniques (scanning electron microscopy, freeze‐fracture and ultrathin sections) expands the observations reported in the original description of the species, Sorogena stoianovitchae is a colpodid ciliate with oral ciliature consisting of 25 ciliated paroral dikinetids on the right and 3‐5 small adoral organelles on the left of an elongated and domed oral slit, resembling that of the genus Platyophrya. Sorogena stoianovitchae divides in the free swimming condition and not in a division cyst, as is the case in the colpodids sensu stricto (s. str.), e.g. Colpoda, Bresslaua. or Tillina, As shown in a detailed light‐microscopy study, morphogenesis in S. stoianovitchae is of the stomatic mode typical for certain colpodid ciliates. Based on the wealth of new information the phylogenetic position of S. stoianovitchae is discussed at some length and arguments are given in favor of the following classifications: S. stoianovitchae Bradbury & Olive, 1980 currently sole member of the family Sorogenidae Bradbury & Olive, 1980; order Sorogenida Foissner, 1985;subclassColpodiaFoissner, 1985; class Colpodea Small & Lynn, 1981. This investigation facilitates the discovery of further members of this genus reported primarily from the tropical and subtropical zone.
Synchronous Division of an Endosymbiotic Methanogenic Bacterium In the Anaerobic Ciliate Plagiopyla Frontata Kahl
Authors: FENCHEL TOM , FINLAY BLAND J.
Published: May 2007

ABSTRACT The life cycle of a methanogenic bacterium, symbiotic within the marine, free‐living anaerobic ciliate Plagiopyla frontata, was studied using light microscopy and transmission electron microscopy (TEM). the bacteria are disc‐shaped. During the growth phase of the host, bacteria and hydrogenosomes (organelles which ferment pyruvate into acetate and hydrogen) are arranged in conglomerates resembling stacks of coins in which bacteria and hydrogenosomes alternate; hydrogenosomes always cap the ends of the stacks. During the growth phase, numbers of hydrogenosomes and bacteria remain constant (about 5,000 and 3,500 per cell, respectively). Hydrogenosomes increase in volume shortly after cell division. Methanogens increase in volume slowly during the growth phase of the ciliate and rapidly when the ciliate begins to divide. the hydrogenosomes divide mainly during the initial phases of cell division while the methanogens divide synchronously during the last phase of ciliate division. the timing of reproduction of the symbionts is controlled by the host‐cell cycle. the ciliate is known to receive an energetic advantage from its symbionts. the suppression of continuous bacterial reproduction may trigger the secretion of excess bacterial production as soluble organic compounds, for use by the ciliate.
In Vitro Development of Exoerythrocytic Forms of Plasmodium Gallinaceum Sporozoites In Avian Macrophages
Authors: RAMIREZ ADELINA D. , ROCHA ELIANA M. M. , KRETTLI ANTONIANA U.
Published: May 2007

ABSTRACT Exoerythrocytic forms of Plasmodium gallinaceum were cultured in vitro using salivary gland sporozoites extracted from experimentally infected Aedes fluviatilis mosquitoes. the host cells were macrophage precursors from chicken bone marrow. At various times after introduction of Sporozoites, the cultures were stained by Giemsa or by immunofluorescence assay (IFA) using anti‐sporozoite‐specific monoclonal antibodies (MAb). the time to complete parasite development in vitro was 50‐70 h. By 70 h, ruptured segmenters and free merozoites were visible within the cells. Inoculation of normal chickens with infected cultures induced parasitemia after a pre‐patent period of 10‐11 days. In vitro young exoerythrocytic forms, late schizonts that include the matured segmenters, and free merozoites shared common antigens with the sporozoites as revealed by IFA using anti‐sporozoite‐specific MAbs. Our data indicate that macrophages support development of P. gallinaceum sporozoites and that the circumsporozoite proteins are present until Ac end of the primary exoerythrocytic schizogony.
Feeding In Planktonic Protozoans: Evidence For Non‐Random Acquisition of Prey
Authors: VERITY PETER G.
Published: May 2007

ABSTRACTThe literature on discriminant feeding by planktonic protozoans using geometric and nongeometric criteria is reviewed with emphasis on recent studies that indicate phagotrophic protists can use information other than particle size or shape to sort among potential prey. Sufficient data are available for ciliates, aplastidic microflagellates, and phagotrophic dinoflagellates. Numerous representative taxa of all three groups have chemosensory capabilities, either to specific chemicals or to prey exudates, that modify their motility patterns resulting in aggregation or dispersal. Representatives of all three groups also have specific prey preferences. These considerations imply, but do not prove, selectivity in feeding through use of chemical cues. Although prey geometry is clearly a first‐order determinant of ingestion through passive mechanical selection, recent studies illustrate that planktonic ciliates and flagellates can use other criteria to discriminate among prey. the evidence clearly implicates use of chemical cues, most likely perceived through contact chemoreception. Filter feeders as well as raptors have such abilities indicating that feeding mechanisms per se do not imply limitations on feeding behavior. Evidence of considerable flexibility and complexity in chemoperceptive feeding suggests that we have only glimpsed the more detailed features of feeding behavior in aquatic protozoans.
Herpetomonas roitmani (Fiorini et al., 1989) N. Comb.: A Trypanosomatid with a Bacterium‐like Endosymbiont in the Cytoplasm
Authors: SILVA PAULO M. FARIA E , SOLÉ‐CAVA ANTONIO M. , SOARES MAURILIO J. , MOTTA MARIA CRISTINA M. , FIORINI JOÁTO E. , SOUZA WANDERLEY DE
Published: May 2007

The trypanosomatid previously described as Crithidia roitmani is characterized here at the ultrastructural and biochemical levels. The data indicates that the parasite belongs to the Herpetomonas genus, and we therefore suggest the flagellate to be denominated as Herpetomonas roitmani n. comb. Cladistic analysis of isoenzyme data generated by eight different enzymes showed that the parasite presented a distinct banding pattern and could be grouped with some Herpetomonas spp., but not with Crithidia spp., used as reference strains. Accordingly, when the parasites were grown for longer periods in Roitman's defined medium, expontaneous differentiation from promastigotes to opisthomastigotes (typical of the Herpetomonas genus) occurred. Transmission electron microscopy revealed the presence of bacterium‐like endosymbionts in the cytoplasm of all evolutive forms of the parasite. All morphological alterations characteristic of endosymbiont‐bearing trypanosomatids could be observed.
The Patterning of Ciliates1
Authors: FRANKEL JOSEPH
Published: May 2007

This past‐presidential address considers the relationship between small‐scale assembly and large‐scale patterning in ciliates. Certain model examples of assembly‐based patterning are reviewed, followed by the introduction of Williams and Honts' concept of “meta‐assembly” as applied to the development of the oral apparatus. The major part of this review then explores two topics: the nature and origin of large‐scale circumferential order, and the manner by which the large‐scale order of cell directions influences the organization of membranelles of the oral apparatus. In this review, I summarize an existing formal description of large‐scale positional order, allude to a more precise abstract theoretical model, and end with a brief discussion of the problem of searching for molecular mechanisms.
Identification of the Mitochondrial Genome in the Chrysophyte Alga Ochromonas danica
Authors: COLEMAN ANNETTE W. , THOMPSON WILLIAM F. , COFF LYNDA J.
Published: May 2007

ABSTRACT. Analysis of total DNA isolated from the Chrysophyte alga Ochromonas danica revealed, in addition to nuclear DNA, two genomes present as numerous copies per cell. The larger genome (˜120 kilobase pairs or kbp) is the plastid DNA, which is identified by its hybridization to plasmids containing sequences for the photosynthesis genes rbcL, psbA, and psbC. The smaller genome (40 kbp) is the mitochondrial genome as identified by its hybridization with plasmids containing gene sequences of plant cytochrome oxidase subunits I and II. Both the 120‐ and 40‐kbp genomes contain genes for the small and large subunits of rDNA. The mitochondrial genome is linear with terminal inverted repeats of about 1.6 kbp. Two other morphologically similar species were examined, Ochromonas minuta and Poteriochromonas malhamensis. All three species have linear mitochondrial DNA of 40 kbp. Comparisons of endonuclease restriction‐fragment patterns of the mitochondrial and chloroplast DNAs as well as those of their nuclear rDNA repeats failed to reveal any fragment shared by any two of the species. Likewise, no common fragment size was detected by hybridization with plasmids containing heterologous DNA or with total mitochondrial DNA of O. danica; these observations support the taxonomic assignment of these three organisms to different species. The Ochromonas mitochondrial genomes are the first identified in the chlorophyll a/c group of algae. Combining these results with electron microscopic observations of putative mitochondrial genomes reported for other chromophytes and published molecular studies of other algal groups suggests that all classes of eukaryote algae may have mitochondrial genomes < 100 kbp in size, more like other protistans than land plants.
Hydrogenosome‐Methanogen Assemblages in the Echinoid Endocommensal Plagiopylid Ciliates, Lechriopyla mystax Lynch, 1930 and Plagiopyla minuta Powers, 19331
Authors: BERGER JACQUES , LYNN DENIS H.
Published: May 2007

ABSTRACT. Lechriopyla mystax Lynch, 1930 and Plagiopyla minula Powers, 1933 contain hydrogenosome‐methanogen assemblages similar to those reported for other plagiopylid ciliates. These assemblages are stacks of elongate ovoid hydrogenosomes alternating with methanogens; these stacks are surrounded by cisternae of the rough endoplasmic reticulum that are often accompanied by Golgi complexes. The individual methanogens in the larger ciliate, L. mystax, are about four times the volume of those in the smaller ciliate, P. minuta, but both ciliates appear to contain Gram‐negative methanococcoid bacteria, possibly Methanoplanus sp. The endoplasmic reticulum‐Golgi complex probably plays a significant role in exploitation of the methanogens by the host ciliate.
Specificity of an Antiserum Produced Against Pseudomicrothorax dubius Trichocysts Prepared by a Rapid Isolation Method
Authors: PECK ROBERT K.
Published: May 2007

ABSTRACT. A rapid method was developed for the isolation of Pseudomicrothorax dubius ciliary and trichocyst fractions which were characterized by SDS‐PAGE followed by combined silver and Coomassie blue staining. Antibodies were prepared against the trichocyst fraction and employed to label Lowicryl thin sections of cells. Trichocysts were strongly labeled, as were the surfaces of the plasma and ciliary membranes. Immunoblots of the trichocyst fraction revealed labeling of major bands at 16–29 kD, characteristic of the trichocyst proteins. On immunoblots of the ciliary fraction, approximately eight bands were labeled, including the major cell surface glycoprotein, the immobilization antigen. Ciliary proteins not located on the membrane surface, such as the tubulins, were not labeled. Absorption of the antiserum against fixed P. dubius cells eliminated the cell surface labeling on Lowicryl sections and on immunoblots of the ciliary fraction. The major trichocyst protein bands were as strongly labeled as with the nonabsorbed antiserum. Labeling of several of the minor, higher molecular weight bands of the trichocyst fraction was eliminated, indicating that they are cell surface contaminants. Of the two major structural components of the trichocyst, the shaft and the arms, the antiserum is shown to react nearly exclusively with the shaft proteins on both Lowicryl sections and immunoblots.
Protein Polymorphism and Evolution in the Genus Tetrahymena1
Authors: WILLIAMS NORMAN E. , HONTS JERRY E. , DRESS VIRGINIA M.
Published: May 2007

ABSTRACT. Immunoblotting tests involving cytoskeletal protein arrays and fluorescence microscopical examinations of whole cells using monoclonal antibody 424A8 gave substantially different results in three evolutionary subgroups within the genus Tetrahymena. These responses are described and some implications of the evolutionary divergence indicated in this ciliated protozoan are discussed.
The Biology of Vampyrophrya pelagica (Chatton & Lwoff, 1930), a Histophagous Apostome Ciliate Associated with Marine Calanoid Copepods
Authors: GRIMES BARBARA HARTLEY , BRADBURY PHYLLIS CLARKE
Published: May 2007

ABSTRACT. The histophagous apostome. l'ampyrophrya pelagica, occurs on calanoid copepods in North Carolina. Its life cycle has two pathways: one when the copepod host is injured; the other when the host is ingested by an invertebrate predator. The ciliate, immediately after encysting on a copepod. metamorphoses to a feeding stage. When its host is injured or ingested by a predator, it excysts enters the wound and ingests the host's cytoplasm. In the single‐host life cycle, after feeding, the ciliate encysts within the cadaver; in the two‐host life cycle, after feeding it encysts upon a substrate. Encysted cells divide into 2–32 migratory tomites. Freed tomites are motionless in the water column until the water is disturbed, at which time they spring in the direction of any vibration, which many times results from a feeding copepod. Tomites select specific hosts, since not all species of copepods are infested. We hypothesize that the single‐host life cycle yields many tomites that heavily infest hosts at random, and passage through the predator (two‐host life cycle) results in fewer, but more widely dispersed tomites that are released continuously. The two‐host life cycle is facultative for the individual, but may be obligate for the continuation of the species.
The Life Cycle of Rotaliella elatiana N. Sp.: A Tiny Macroalgavorous Foraminifer from the Gulf of Elat1
Authors: PAWLOWSKI JAN , LEE JOHN J.
Published: May 2007

ABSTRACT. A new foraminiferan species, Rotaliella elatiana n. sp., was isolated in the Gulf of Elat, where it lives in association with a macrophytic green alga, Enteromorpha. The agamont of this tiny new species has a transparent test composed of a bilocular embryonic chamber followed by six to seven trochospirally coiled inflated chambers. The spiral sutures are undulated. The umbilical side has numerous denticules and has radial grooves. The gamont has only one inflated chamber. Rotaliella elatiana has a classical, heterophasic life cycle, with a regular alternation of diploid agamontic phase and haploid gamontic phase. The gamontic phase of the life cycle is exceptionally reduced and the uninucleated gamonts pair immediately after they build their first chamber. A few cases of autogamic reproduction were observed. R. elatiana is a heterocaryotic species; agamonts have one somatic and two to three generative nuclei.
Molecular Factors Responsible for Host Cell Recognition and Invasion in Plasmodium falciparum1
Authors: SAM‐YELLOWE TOBILI Y.
Published: May 2007

ABSTRACT. In Plasmodium falciparum. the rhoptries involved in the invasion process are a pair of flask‐shaped organelles located at the apical tip of invading stages. They, along with the more numerous micronemes and dense granules, constitute the apical complex in Plasmodium and other members of the phylum Apicomplexa. Several proteins of varying molecular weight have been identified in P. falciparum rhoptries. These include the 225‐, 140/130/110‐, 80/60/40‐, RAP‐1 80‐, AMA‐1 80‐, QF3 80‐, and 55‐kDa proteins. Some of these proteins are lost during schizont rupture and release of merozoites. Others such as the 140/130/110‐kDa complex are transferred to the erythrocyte membrane during invasion. The ring‐infected surface antigen (RESA). a 155‐kDa polypeptide located in dense granules also associates with the erythrocyte membrane during invasion. Erythrocyte‐binding studies have demonstrated that both the 140/130/110‐kDa rhoptry complex and RESA bind to inside‐out‐vesicles (IOVs) prepared from human erythrocytes. The 140/130/110‐kDa complex also binds to erythrocyte membranes prepared by hypotonic lysis. These proteins, however, do not bind to intact human erythrocytes. In a heterologous erythrocyte model, both the 140/130/110‐kDa complex and RESA are shown to bind directly to mouse erythrocytes. Other studies have shown that RESA associates with spectrin in the erythrocyte cytoskeleton. We have recently developed a liposome‐binding assay to demonstrate the lipophilic binding properties of the P. falciparum rhoptry complex of 140/130/110 kDa. The rhoptry complex binds to liposomes containing neutrally, positively, and negatively charged phospholipids. However, liposomes containing phosphatidylethanolamine compete effectively for rhoptry protein binding to mouse erythrocytes. The rhoptry complex also binds to membrane and inside‐out‐vesicles prepared from human erythrocytes and erythrocytes from other species. The rhoptry complex associated with the erythrocyte membrane in ring‐infected erythrocytes is accessible to cleavage by phospholipase A. Studies are in progress to identify the molecular epitopes on the individual proteins within the complex responsible for lipid interaction in the erythrocyte bilayer and to determine the specificity of the phospholipid interaction using erythrocyte phospholipids.
Bacterial‐Endosymbiote‐Derived Lipopolysaccharides on Amoeba Symbiosome Membranes
Authors: CHOI EUI Y. , JEON KWANG W.
Published: May 2007

ABSTRACT. Monoclonal antibodies were obtained against lipopolysaccharides of Gram‐negative bacterial endosymbiotes in amoebae and were used to determine the origin and distribution of the antigens. The lipopolysaccharides were located on endosymbiote's surfaces as determined by indirect immunofluorescence staining under both light and electron microscopes. In addition, host symbiosome membranes enclosing the endosymbiotes also contained the same lipopolysaccharides on the cytoplasmic side as shown by indirect immunofluorescence staining after intracellular injection of anti‐lipopolysaccharide antibodies. This is the first report for the presence of symbiote‐derived lipopolysaccharides on the host symbiosome membranes, and their possible roles are discussed in relation to the prevention of lysosomal fusion with symbiosomes.
Aggregata dobelli N. Sp. and Aggregata millerorum N. Sp. (Apicomplexa: Aggregatidae) from Two Species of Octopus (Mollusca: Octopodidae) from the Eastern North Pacific Ocean
Authors: POYNTON SARAH L. , REIMSCHUESSEL RENATE , STOSKOPF MICHAEL K.
Published: May 2007

ABSTRACT. Gamogony and sporogony of two new species of Aggregata (Apicomplexa: Aggregatidae) commonly were observed during histopathological examination of the digestive tracts of octopuses from the National Aquarium in Baltimore. North Pacific giant octopus, Octopus dofleini martini Pickford 1964, from British Columbia and Washington state were infected with Aggregata dobelli n. sp. Sporocysts were smooth‐surfaced, dark‐staining, subspherical to subovoid, typically 18–31 μm long by 15–27 μm wide, and contained 9–22 sporozoites, 18–23 μm long. California two‐spotted octopus, Octopus bimaculoides Pickford and McConnaughey 1949, from California were infected with Aggregata millerorum n. sp. Sporocysts were smooth‐surfaced, dark‐staining, and subspherical to subovoid, 12–20 μm long by 11–17 μm wide, and contained 8–10 sporozoites, 18–31 μm long. Both species infected the noncuticularized spiral caecum and intestine; A. millerorum n. sp. also infected the cuticularized esophagus and crop. Both parasites were present in the submucosa, muscularis, and serosa. Our observations of Aggregata infections in cuticularized regions of the gut and in the muscularis and serosa appear to be novel. Associated pathologic features included hypertrophy of invaded cells, edema, inflammation, and ulceration.
Observations on First‐Generation Schizogony of Leucocytozoon caulleryi in Chickens
Authors: MORII T. , FUKUDA M.
Published: May 2007

ABSTRACT. First and second generation schizogony of Leucocytozoon caulleryi occurred in chickens infected with sporozoites. First generation schizogony was studied by light and electron microscopy. First‐generation schizonts were first detected in capillary endothelial cells in the spleen, lung, liver, and bursa of Fabricius between 3 and 6 d post‐sporozoite inoculation (DPI). The schizonts ranged from 15 to 65 μm in diameter and were surrounded by a thin pellicle. Early schizonts contained numerous round or oval nuclei, endoplasmic reticulum, and mitochondria. The schizonts reached maturity 5 DPI and produced first‐generation merozoites which were released into the peripheral bloodstream. The merozoites. which were infective to chickens, measured 7.1 μm in length. They were slender and had a large nucleus, a mitochondrion, and an apical complex consisting of three polar rings, rhoptries, numerous micronemes. The morphology of first‐generation merozoites was different from that of second‐generation merozoites.
Phylogenetic Analysis of the Diplomonadida (Wenyon, 1926) Brugerolle, 1975: Evidence for Heterochrony in Protozoa and Against Giardia lamblia as a “Missing Link”
Authors: SIDDALL MARK E. , HONG HENRY , DESSER SHERWIN S.
Published: May 2007

ABSTRACT. A suite of 23 ultrastructural characters was used in a phylogenetic analysis of the protozoan order Diplomonadida. A single most parsimonious solution was found, with a length of 38 transformations and a consistency index of 0.84. The cladogram supports previous hypotheses of the relationships of the genera in the suborder Diplomonadina, as well as the inclusion of the genera Enteromonas and Trimitus in the order. Heterochrony is suggested in the change to binary axial symmetry, as hypermorphosis resulting from delayed cytokinesis in the ancestor. Hypotheses regarding a pivotal position for Giardia lamblia in the evolution of eukaryotes are inconsistent with the phylogeny proposed here.
Characterization of the Calcium‐Binding Contractile Protein Centrin from Tetraselmis striata (Pleurastrophyceae)
Authors: COLING DONALD E. , SALISBURY JEFFREY L.
Published: May 2007

ABSTRACT. Centrin is a major protein of the contactile striated flagellar roots of the green alga Tetraselmis striata. We present a newly modified procedure for the preparation of centrin in sufficient quantity and purity to allow for detailed biochemical characterization. We establish that centrin purified by differential solubility, followed by phenyl‐Sepharose and DEAE‐Sephacel chromatography is identical with the protein extracted directly from striated flagellar roots with regard to molecular weight, isoelectric point, and calcium‐dependent behavior in SDS‐PAGE. We also compare the biochemical properties of purified centrin with calmodulin isolated from Tetraselmis and calmodulin isolated from mammalian brain. Centrin can be fully distinguished from either algal or mammalian calmodulin on the basis of molecular weight, isoelectric point, calcium‐dependent behavior in SDS‐PAGE, proteolytic peptide maps, amino acid composition, ability to activate bovine brain phosphodiesterase, and reactivity with specific antibodies.