bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzymes of Ornithine‐Arginine Metabolism in Trypanosomatids of the Genus Phytomonas1
Authors: Camargo E. Plessmann , Silva Solange , Roitman Isaac , De Souza Wanderley , Jankevicius J. Vitor , Dollet Michel 
Published: May 2007

ABSTRACTTrypanosomatids recently isolated from the plants Euphorbia pinea, E. characias, E. hyssopifolia, Manihoi esculenta (cassava) and Lycopersicon sp. (tomato) plus the McGhee‐Postell isolate of Phytomonas davidi have been examined for the presence of enzymes of ornithine‐arginine metabolism. Arginase (EC 3.5.3.1) was not detected in the flagellates examined whereas arginine deiminase (EC 3.5.3.6) and citrullinehydrolase (EC 3.5.1.20) were present in all organisms. Phytomonas davidi and the isolate from E. hyssopifolia, besides these enzymes, also had ornithine carbamoyltransferase (EC 2.1.3.3). The enzymic constitution of these flagellates is compared from a taxonomic standpoint to that of previously studied trypanosomatids.
Electrophoretic Analysis of Isoenzymes in the Identification of Trypanosomatids of the Genus Phytomonas1
Authors: Vainstein Marilene Henning , Da Silva João Batista Tavares , De Lima Vilneide M. Q. Gonçalves , Roitman Isaac , De Souza Wanderley , Dollet Michel , Camargo E. Plessmann 
Published: May 2007

ABSTRACTFive strains of trypanosomatids of the genus Phytomonas, isolated from different species of Euphorbia {Euphorbia heterophylla, E. characias, E. pinea, E. hyssopifolia) and from Manihot escutenta, were cultured and compared through the electrophoretic mobility of isoenzymes of six enzymes: aspartate aminotransferase (EC 2.6.1.1), alanine aminotransferase (EC 2.6.1.2), phosphoglucomutase (EC 2.7.5.1), glucose‐6‐phosphate dehydrogenase (EC 1.1.1.49), glucosephosphate isomerase (EC 5.3.1.9), and malate dehydrogenase (EC 1.1.1.40). The strains could be distinguished from one another by their respective isoenzyme profiles.
Sarcocystis in Muscles of Raccoons (Procyon lotor L.)1
Authors: Kirkpatrick C. E. , Hamir A. N. , Dubey J. P. , Rupprecht C. E. 
Published: May 2007

ABSTRACTSarcocysts of Sarcocystis sp. were found in 26 (50%) of 52 raccoons (Procyon lotor) from Ohio, Pennsylvania, Florida, and Maryland. Although only 4 (7.7%) of 52 cardiac muscle specimens were found to contain sarcocysts, 25% to 36.5% of tongue, diaphragm, masseter muscle, and esophagus specimens were found infected. By light microscopy, sarcocyst walls were <3 μm thick and had no conspicuous projections; interior septa were indistinct. By transmission electron microscopy, sarcocyst walls had short (mean = 2.7 μm), villus‐like protrusions; thin septa were seen within the sarcocysts. The raccoon may be an intermediate host for a Sarcocystis sp. that completes its life cycle in an unidentified, wild carnivore.
Ultrastructural Features of Three Ectocommensal Protozoa Attached to the Gills of the Red Swamp Crawfish, Procambarus clarkii (Crustacea: Decapoda)1
Authors: VOGELBEIN WOLFGANG K. , THUNE RONALD L. 
Published: May 2007

ABSTRACTBecause heavy branchial infestations are thought to interfere with respiration, we examined the attachment of three stalked ciliates commonly found in the branchial chambers of Louisiana crawfish. Attachments by Cothurnia sp., Epistylis sp. and Acineta sp. differ in their fine structure. Stalks of the peritrichous ciliates. Cothurnia and Epistylis, contain striated tubules that differ in their arrangement, diameter, and in the periodicity of their striations. In both species the striated tubules branch within the basal disk and attach to a pad of adhesive material secreted by the organism during initial attachment to the gill surface. The stalk of the suctorian Acineta is composed of a striated honeycomb‐like matrix. Within the basal disc the matrix is disorganized; however, striated elements anchor the stalk to a pad of adhesive material. Attachment sites also differ in the amount of secretory material deposited. Cothurnia forms a multi‐layered, granular pad; Epistylis forms an indistinct, microfibrillar layer, and Acineta deposits a thick mucoid pad. None of the ciliates appear to damage the gill epicuticle nor is there an obvious host response. Harmful effects are probably limited to a decrease in respiratory surface area and disruption of normal water flow patterns. This may impair respiration sufficiently to increase the susceptibility of crawfish to low dissolved oxygen concentrations encountered periodically in commercial crawfish ponds.
Eimeria sinaitae n. sp. (Apicomplexa: Eimeriidae) from the Rock Agama (Agama sinaita) in Saudi Arabia
Authors: KASIM AHMED A. , AL SHAWA YASER R. 
Published: May 2007

ABSTRACTEimeria sinaitae n. sp. is described from the gall bladder of Agama sinaita from Wasie, Saudi Arabia. Sporulated oocysts are elongate‐ellipsoid 34.4 times 22.0 (29.0–40.0 times 17.4–24.5) μm. Oocyst wall is smooth, greenish yellow, 1.2 (1.0–1.4) μm thick, and two‐layered. Micropyle, polar granule, and oocyst residuum are absent. Sporocysts are ellipsoid 11.4 times 7.6 (9.8–15.0 times 6.7–9.0) μm. Sporocyst residuum is present. The sporocysts lack a Stieda body. Sporozoites are crescent‐shaped, blunt at one end and tapered at the other. Eimeria species from Agamidae are compared.
Euplotes Cytoskeleton: Tubulin and Microtubular Systems in Interphase1,2
Authors: DELGADO PILAR , CALVO PURIFICACION , TORRES ANTONIO 
Published: May 2007

ABSTRACTThe Euplotes cytoskeleton obtained by treatment with Triton X‐100 in a microtubule‐stabilizing buffer has been studied by electron microscopy and SDS‐polyacrylamide electrophoresis. An antiserum has been prepared using the tubulin band from preparative gels of Euplotes cytoskeletons as an antigen. This antiserum reacts with the tubulin from different ciliated protozoa but fails to recognize the vertebrate tubulin by immunoblotting. Immunoblotting studies have demonstrated a slower electrophoretic mobility for the α‐tubulin of Euplotes and Oxytricha than that of Paramecium and Tetrahymena. A cytoplasmic microtubular network in Euplotes has been revealed by indirect immunoftuorescence using both an anti‐α‐tubulin monoclonal antibody directed against chick brain tubulin and an antiserum raised against the tubulin of Euplotes.
Purification of Plasma Membrane from Acanthamoeba castellanii1
Authors: CLARKE BARBARA J. , HOHMAN THOMAS C. , BOWERS BLAIR 
Published: May 2007

ABSTRACTA simple method for isolation of plasma membrane from Acanthamoeba using self‐generating gradients of Percoll is described. To obtain a membrane marker, intact amoebae were radioiodinated and the distribution of the radiolabel was followed through the plasma membrane isolation procedure. The purity of isolated plasma membrane was assessed by enrichment of radiolabel, by electron microscopy, and by enzymatic assays for contaminating membranes. As judged from enrichment of radiolabel, a 37‐fold purification of plasma membrane was obtained. We estimate that 80% of the total protein was from plasma membrane and 10% from membrane‐associated actin.
Virulence of Paramoeba invadens Jones (Amoebida, Paramoebidae) from Monoxenic and Polyxenic Culture1
Authors: JELLETT JOANNE F. , SCHEIBLING ROBERT E. 
Published: May 2007

ABSTRACTParamoeba invadens is a pathogenic marine amoeba responsible for mass mortalities of sea urchins (Strongylocentrotus droebachiensis) along the Atlantic coast of Nova Scotia in the early 1980's. The amoeba has been maintained in vivo in S. droebachiensis for five years in the laboratory without observable loss of virulence. Paramoeba invadens was cultured polyxenically (on mixed marine bacteria) and monoxenically (on a single strain of Pseudomonas nautica) on non‐nutrient agar for 58 weeks and 19 weeks respectively. Pathogenicity tests showed some loss of virulence in monoxenic culture after 15 weeks and in polyxenic culture after 58 weeks. Polyxenic culture is recommended for long‐term culture of P. invadens although periodic passage of the amoeba through the sea urchin host may be required to maintain virulence for periods exceeding one year.
Impairment of T‐Helper Function by a Plasmodium berghei‐Derived Immunosuppressive Factor1
Authors: SROUR EDWARD F. , SEGRE MARIANGELA , SEGRE DIEGO 
Published: May 2007

ABSTRACTMice injected with an immunosuppressive factor (ISF) extracted from Plasmodium berghei‐infected rat erythrocytes have a reduced antibody response to unrelated antigens. T‐cells from ISF‐treated mice failed to provide adequate help to naive, syngeneic B‐cells in the primary IgM response in vitro to sheep red blood cells and to dinitrophenylated keyhole limpet hemocyanin. The same T‐cells, however, were able to cooperate with memory B‐cells in the secondary IgG response. No other cellular deficit was delected in ISF‐treated mice; B‐cells and macrophages behaved normally, and there was no detectable excess of suppressor cells. The T‐cell impairment was not reflected in decreased production of interleukin 2, but was also shown by the diminished delayed type hyperaensitivity reaction to sheep red blood cells of ISF‐treated mice.
Transmission Electron Microscopical Observations on Stomatogenesis during Metamorphosis of Eufolliculina uhligi (Ciliophora: Heterotrichida)1
Authors: MULISCH MARIA , HAUSMANN KLAUS 
Published: May 2007

ABSTRACTStomatogenesis during metamorphosis of the marine loricate ciliate, Eufolliculina uhligi, was observed by transmission electron microscopy. Kinetosome proliferation in the stomatogenic territory leads to the formation of an anarchic field. This separates into the left adoral and the right paroral primordia. Both primordia consist of pairs of kinetosomes. One kinetosome of a pair is associated with one transverse and two postciliary microtubules; the other has one transverse microtubule. The postciliary microtubules of the adoral kinetosomes become divergent; those of the paroral kinetosomes become convergent. The adoral kinetosomes arrange in promembranelles. Then a third row of kinetosomes is produced anteriorly to each promembranelle. This third row is short at the peristome but longer in the buccal area. The paroral kinetosomes form a stichodyad. The buccal part of the paroral primordium is resorbed during formation of the buccal cavity. Stomatogenesis ends with the development of a functioning cytostome. During this process, the postciliary microtubules of the buccal adoral membranelles elongate and become associated with cytopharyngeal vesicles. Fusion of these vesicles with the cytostome has been observed some time after the completion of the oral structures.
Genetic Characterization and Use of a Restriction Fragment Length Variant in the Hypotrichous Ciliate Euplotes crassus1
Authors: BAIRD SCOTT E. , KLOBUTCHER LAWRENCE A. 
Published: May 2007

ABSTRACTTwo forms of a macronuclear DNA molecule differing in the presence or absence of a restriction endonuclease recognition site have been detected in the hypotrichous ciliate Euplotes crassus. Through a series of genetic crosses the two forms were shown to be allelic, being derived from a single micronuclear genetic locus. This restriction fragment length variant (RFLV) was used as a genetic marker to determine that the migratory and stationary pronuclei generated during mating can be genetically non‐identical. In addition, the RFLV was used to investigate the efficiency of processing of the alternate alleles during macronuclear development and their subsequent transmission during vegetative growth. Little or no bias in the processing and/or amplification of the two alleles was observed during macronuclear development. During vegetative growth, however, changes in the relative amounts of the two alleles were observed.
Identification of C3 Acceptors Responsible for Complement Activation in Crithidia fasciculata1
Authors: GÜTHER MARIA LUCIA S. , TRAVASSOS L. R. , SCHENKMAN S. 
Published: May 2007

ABSTRACTCrithidia fasciculata, an insect trypanosomatid is readily lysed by normal human serum at concentrations as low as 3%. Lysis occurs in the presence of Mg+2‐EGTA and is antibody independent, indicating that the alternative pathway of complement activation is involved. Analysis of [131I]C3 deposition on C. fasciculata cells using C8‐deficient serum, revealed that about 4 times 105 C3 molecules bound to each cell. Most of the C3 was bound to cells as C3b, part of it forming high molecular weight complexes, which could be dissociated by methylamine treatment at alkaline pH. To characterize the C3 acceptors on C. fasciculata, surface‐iodinated cells were incubated with C8D or heat‐inactivated serum, extracted and immunoprecipitated with anti‐C3 or anti‐arabinogalactan antisera. Analysis of the immunoprecipitated material on SDS gels showed high‐molecular weight components, which disappeared after methylamine treatment, giving rise to a component of 200 kDa molecular size. This 200‐kDa component corresponded to a purified arabinogalactan complex, which was immunoprecipitated from labeled cell extracts, without incubation with C8D, using anti‐arabinogalactan antibodies. These results suggest that the arabinogalactan glycoconjugate is a C3 acceptor in C. fasciculata during complement activation. Purified arabinogalactan complexes were able to inactivate C3 in vitro. Solubilization in KOH to cleave the peptide moiety rendered it unable to inactivate C3. Apparently, the aggregated state of the purified arabinogalactan component at the cell surface is important for C3 deposition and activation.
Trypanosoma cruzi: Cell Biological Behavior of Epimastigote and Amastigote Forms in Axenic Culture
Authors: ENGEL JUAN C. , DVORAK JAMES A. 
Published: May 2007

ABSTRACTA simple protocol to maintain Trypanosoma cruzi amastigote stocks indefinitely in axenic culture is described. The growth characteristics of amastigotes differ markedly from epimastigotes cultured under identical conditions. The amastigotes replicate for two generations, followed by a transformation to epimastigotes and resumption of growth. By changing the culture medium at the end of the second amastigote generation, transformation to epimastigotes is inhibited. Therefore, the protocol used to maintain amastigotes in culture is based upon changing the culture medium at preselected intervals. Flow cytometric analyses indicate that at the end of the exponential phase of growth the amastigote population consists of predominately G1 cells; changing the medium induces the amastigotes to begin a para‐synchronous round of DNA synthesis without a pre‐replicative lag phase. In contrast, when exponentially growing or stationary‐phase epimastigotes are transferred to fresh culture medium, they grow asynchronously until reaching a limiting cell density. Amastigotes also differ from epimastigotes in being resistant to the lytic activity of human complement. These data demonstrate that marked differences in phenotypic expression exist between developmental stages of T. cruzi even when cultured under identical conditions.
Demonstration of Acid Phosphatase in Eimeria spp.: Partial Characterization of the Enzyme in E. vermiformis1,2
Authors: HOSEK JAMES E. , TODD KENNETH S. , KUHLENSCHMIDT MARK S. 
Published: May 2007

ABSTRACTSporozoite extracts of E. vermiformis, E. stiedai, and E. tenella are rich in acid phosphatase activity. They contain specific enzyme activities equal to or greater than those reported for other highly virulent protozoan parasites. The absolute amount of enzyme activity per oocyst dramatically increases during sporulation of E. stiedai and E. vermiformis. Partial characterization of the acid phosphatase activity of E. vermiformis indicates that sporozoites account for greater than 92% of the total activity in sporubted oocysts, that the enzyme is resistant to inhibition by tartrate, and that it can be separated into two forms by anion exchange chroma‐tography.
Axenic Cultivation of Phytomonas (Trypanosomatidae) Associated with Laticiferous Plants in Suriname1
Authors: KASTELEIN PIETER , PARSADI MALA 
Published: May 2007

ABSTRACTUsing variously enriched media, axenic cultures were obtained of Phytomonas spp. associated with Allamanda cathartica, Mandevilla scabra, and Rhabdadenia biflora (Apocynaceae), and Blepharodon nitidus (Asdepiadaceae) and Euphorbia hirta (Euphor‐biaceae). Cultures were usually subcultured once every week for many weeks in succession. Attempts to grow the flagellates from Bonafousia tetrastachya (Apocynaceae), Cecropia palmata (Cecropiaceae), and Euphorbia hyssopifolia (Euphorbiaceae) were unsuccessful. The “phytomonads” in latex of different host plants showed morphological differences, whereas the cultured flagellates were similar in morphology whatever the host plant source or culture medium.
Two New Species of Eimeria from Peacocks (Pavo cristatus) in Saudi Arabia1
Authors: AMOUDI MIKKY A. 
Published: May 2007

ABSTRACTFifteen fecal samples from peacocks (Pavo cristatus) in Saudi Arabia contained oocysts of Eimeria riyadhae n. sp. in two peacocks and oocysts of E. arabica n. sp. in one peacock. Sporulated oocysts of Eimeria riyadhae are ellipsoidal, 27–30.5 times 20.5–25 (28.8 ± 1.3 × 22.4 ± 1.6) μm, with a two‐layered wall and bilobed polar body, but without a micropyle or residuum. The sporocysts are ovoid, 11–14.5 × 6.5–8 (13.2 ± 1.2 × 7.2 ± 0.6) μm with a thick, knob‐like Stieda body and a residuum. Sporulated oocysts of Eimena arabica are spheroidal, 17.5–21.5 × 17.5–21.5 (19.2 ± 1.6 × 19.2 ± 1.6) μm, with a two‐layered wall and two refractile polar bodies, but without a micropyle or residuum. The sporocysts are elongate ovoid, 9.5–12 × 4–6.5 (11.2 ± 0.9 × 5.5 ± 0.88), with a small crescent‐shaped Stieda body. The host bird belongs to the order Galliformis.
Ichthyophthirius (Ciliophora): Population Studies Suggest Reproduction in Host Epithelium1
Authors: EWING MARGARET S. , EWING S. A. , KOCAN KATHERINE M. 
Published: May 2007

ABSTRACTEvidence that Ichthyophthirius multifiliis trophonts may reproduce within the epithelium of the host was obtained from experimental infections of channel catfish. Mean number of parasites spontaneously leaving the fish increased from 0 on day 3 postexposure (PE) to 66.5 per fish on day 7 PE. Mean population density in fin, however, increased five‐fold from day 3 to day 5 PE in the absence of opportunity for reinfection. At day 3 PE, 100% of parasite loci in fin and gill arches contained solitary trophonts. At day 4 PE, 10% of loci in fin contained clusters of two trophonts; at day 7 PE, 69% contained clusters of two or more trophonts. The first clusters of four trophonts in fin were observed day 5 PE and of eight trophonts, day 8 PE. Trophonts in clusters were flattened against one another.
Isolation and Characterization of Chlamydomonas reinhardtii Mutants with Defects in the Induction of Flagellar Protein Synthesis after Deflagellation1,2
Authors: LEFEBVRE PAUL A. , BARSEL SARA‐ELLEN , WEXLER DANIEL E. 
Published: May 2007

ABSTRACTAmputating the flagella of Chlamydomonas reinhardtii stimulates increased synthesis of many flagellar proteins within 30 min. We have isolated a series of mutants which are defective in this stimulation, taking advantage of the fact that cells which cannot stimulate flagellar protein synthesis cannot regenerate flagella. More than a dozen mutants which have flagella, but cannot regenerate them after amputation, were isolated and studied by in vivo labeling to identify those non‐regenerator mutants which were specifically defective in the induction of flagellar protein synthesis. Ten such mutants have been identified, and in each of them flagellar amputation does not stimulate the synthesis of any of the major flagellar proteins. At least four of the mutants display an interesting conditional phenotype. The synthesis of flagellar proteins after deflagellation is defective only in gametic cells; vegetative cells of these mutants are capable of flagellar protein synthesis after flagellar amputation.
Scanning Electron Microscopy of the Adoral Ciliary Zone of Cycloposthium Bundle (Ciliophora, Entodiniomorphida)1
Authors: IMAI SOICHI , YAMAZAKI YASUYO 
Published: May 2007

ABSTRACTThe adoral ciliary zone of Cycloposthium spp., inhabiting the large intestine of the horse, was studied by scanning electron microscopy. It could be divided into four parts: outer, inner, left, and right zones. The outer zone, extending on the anterior periphery of the apical cone of the body, had 20 tuft‐like syncilia arranged radially around the longitudinal axis. Each ciliary tuft consisted of about 170 cilia, and in cross section it had a rectangular shape. The cilia of the inner zone, situated at the top of the apical cone, were aggregated irregularly to form shorter bundles than the tufts of the outer zone. The innermost cilia of this zone were shorter than the outermost. There was a distinct non‐ciliated border between the outer and inner zones. A horseshoe‐like operculum having no cilia was present at the center of the adoral ciliary zone, and the opening of the vestibulum was situated as a cleft crossing from the center to the right periphery of this zone. No cilia extended onto the vestibular wall. The left ciliary zone was situated beneath the outer zone and consisted of five short rows of barren kinetosomes of which only the central row possessed very short cilia. The right ciliary zone, consisting of a few rows of cilia situated at the bottom of the inner adoral lip, was also easily distinguished from the other ciliary zones. This zone was interpreted as an extension of the outer adoral zone passing along the right side of the apical cone. These ciliary zones were considered to be highly differentiated and useful for both movement of and ingestion of food.
Improved Method for High‐Yield Excystation and Purification of Infective Sporozoites of Eimeria spp.1
Authors: HOSEK JAMES E. , TODD KENNETH S. , KUHLENSCHMIDT MARK S. 
Published: May 2007

ABSTRACTThis report describes a new, gentle procedure for rapid and efficient excystation of large numbers of infective sporozoites of Eimeria vermiformis and Eimeria stiedai. Excysted sporozoites are purified using modifications of a previously described ion‐exchange chromatography method. The procedure avoids physical breakage of oocysts and results in greater than 70% recovery of the sporozoites present as sporulated oocysts (i.e. 5–6 sporozoites per sporulated oocyst). The recovered sporozoites are greater than 95% pure and are infective in vivo. We routinely isolate greater than 2 times 108 sporozoites without the use of specialized or expensive equipment.
Organization of the Euplotes crassus Micronuclear Genome1
Authors: JAHN CAROLYN L. , NILLES LAURA A. , KRIKAU MARK F. 
Published: May 2007

ABSTRACTEuplotes crassus, like other hypotrichous ciliated protozoa, eliminates most of its micronuclear chromosomal DNA in the process of forming the small linear DNA molecules that comprise the macronuclear genome. By characterizing randomly selected lambda phage clones of E. crassus micronuclear DNA, we have determined the distribution of repetitive and unique sequences and the arrangement of macronuclear genes relative to eliminated DNA. This allows us to compare the E. crassus micronuclear genome organization to that of another distantly related hypotrichous ciliate, Oxytricha nova. The clones from E. crassus segregate into three prevalent classes: those containing primarily eliminated repetitive DNA (Class I); those containing macronuclear genes in addition to repetitive sequences (Class II); and those containing only eliminated unique sequence DNA (Class III). All of the repetitive sequences in these clones belong to the same highly abundant repetitive element family. Our results demonstrate that the sequence organization of the E. crassus and O. nova micronuclear genomes is related in that the macronuclear genes are clustered together in the micronuclear genome and the eliminated unique sequences occur in long stretches that are uninterrupted by repetitive sequences. In both organisms a single repetitive element family comprises the majority of the eliminated interspersed middle repetitive DNA and appears to be preferentially associated with the macronuclear sequence clusters. The similarities in the sequence organization in these two organisms suggest that clustering of macronuclear genes plays a role in the chromosome fragmentation process.