bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Cytology of Sheep Rumen Ciliates. I. Ultrastructure of Epidinium caudatum Crawley1
Authors: FURNESS D. N. , BUTLER R. D. 
Published: May 2007

ABSTRACTEpidinium caudatum has an anterior vestibulum containing the adoral zone syncilia (AZS) on an extrusible peristome. The cytopharyngeal structures include a funnel‐shaped arrangement of nematodesmata, longitudinal and transversely oriented microtubular ribbons all of which are located in the peristome, a structure which also contains filamentous phagoplasm. The origins of the microtubular ribbons indicate affinities to the rhabdos type of cytopharynx. The peristomal base is continuous with the tubular esophagus, the region connecting the two being ensheathed by a fibrous layer and low density cytoplasm. The esophagus has a microtubular/microfilamentous wall. A distinct cytoproct with associated myonemal structures occurs posteriorly. The skeletal plates consist of a large number of interconnected, variably shaped platelets and may have dual skeletal and storage functions. The endoplasm is more vesicular than the ectoplasm, the two separated by a fibrous boundary layer. The five‐layered cortex has an external glycocalyx, a plasma membrane with two subtending membranes, homogeneous, microtubular, and microfilamentous layers. The syncilia of the AZS are mounted in a U‐shaped band on the peristome with transversely oriented kinetics consisting of kinetosomes linked by a sub‐kinetosomal rod. There is a bifurcated kinetodesma, dense support material forming a lateral spur with associated transverse microtubules, and postciliary, interkinetal, and occasional basal microtubules, nematodesmata, and a subciliary reticulum. A barren, possibly vestigial, somatic infraciliature consists of non‐ciliated kinetosomes and a basal striated fiber with associated basal and perpendicular (cortical) microtubules.
Scanning Electron Microscopy of Attached Trophozoites of Pathogenic Entamoeba histolytica1
Authors: GONZALEZ‐ROBLES ARTURO , MARTINEZ‐PALOMO ADOLFO 
Published: May 2007

ABSTRACTThe surface morphology of Entamoeba histolytica trophozoites of HM 1:IMSS (axenic and monoxenic) and HK9 (axenic) strains cultured on plastic and MDCK cell substrates was examined using scanning electron microscopy (SEM). The conditions for processing trophozoites were determined by comparing the SEM observations with the morphology of living amebas examined by light microscopy. The most frequent surface differentiations in all the amebas observed with SEM were lobopodia. Round cytoplasmic projections were found in approximately half of the axenic amebas. Endocytic stomas and filopodia were more common in monoxenic cultures while the uroid was found in only 2–8% of all examined amebas. The basal surfaces of the trophozoites, involved in both attachment and cytolysis, showed no unusual features, except for the presence of a small number of short filopodia at the outer edge. No differences were found in the morphology of amebas grown on artificial and natural substrates. These observations demonstrate that there are significant quantitative differences in the surface morphology of cultured trophozoites of different strains of E. histolytica and that association with bacteria produces an increase in the relative number of surface specializations of the parasite.
Strain‐Specific Proteins of Symbiont‐Containing Amoeba proteus Detected by Two‐Dimensional Gel Electrophoresis1
Authors: AHN T. I. , JEON K. W. 
Published: May 2007

ABSTRACTTwo‐dimensional gel electrophoresis was used to compare the protein composition of normal (D strain) and symbiont‐containing (xD strain) A. proteus. Over 500 different peptide spots could be identified on a typical gel of cytosol proteins. In addition to differences in a few minor peptides, one prominent polypeptide with an isoelectric point of about 5.5 and a molecular weight of about 29,000 was present in the cytoplasm of symbiont‐containing amoebae and in the endosymbionts but not in D‐strain amoebae. When endosymbionts were removed from xD‐strain amoebae, the xD‐specific polypeptide also disappeared, suggesting that it is produced by the endosymbionts.
Fine Structure of Yellow‐Brown Symbionts (Prymnesiida) in Solitary Radiolaria and Their Comparison with Similar Acantharian Symbionts1
Authors: ANDERSON O. R. , SWANBERG N. R. , BENNETT P. 
Published: May 2007

ABSTRACTYellow‐brown, algal symbionts varying in diameter from approximately 5 μ m to 20 μ m, associated with solitary Radiolaria with spongiose skeletons (i.e. Spongodrymus sp.), exhibit fine structural features resembling the Prymnesiida (botanical class, Prymnesiophyceae). A large central vacuole is surrounded by a thin layer of cytoplasm containing plastids with lamellae composed of three thylakoids and granular pyrenoids with internal tubules immersed between the thylakoids. The pyrenoids lack internal thylakoid membranes. The nucleus is surrounded by a dilated cisterna of the nuclear envelope that also encloses the plastids and gives rise to saccules of the endoplasmic reticulum. The algal symbionts appear coccoid; hence no flagella nor surface scales were observed. The symbiont fine structure is compared to similar yellow‐brown symbionts associated with Acantharia. Thus far, three kinds of algal symbionts have been observed to be associated with solitary Radiolaria: dinoflagellate, prasinomonad, and this apparent prymnesiomonad.
Altered Flagellar Size‐Control in shf‐1 Short‐Flagella Mutants of Chlamydomonas reinhardtii
Authors: JARVIK JONATHAN W. , REINHART FREDERICK D. , KUCHKA MICHAEL R. , ADLER SALLY A. 
Published: May 2007

ABSTRACTTwo allelic Mendelian mutations which confer a short flagella phenotype were used to explore flagellar size control in Chlamydomonas reinhardtii. When mutant/wild type quadriflagellate dikaryon cells were constructed, their two short flagella rapidly grew out to near wild type length. The kinetics of elongation suggest that the flagellar assembly process is not intrinsically self‐limiting as a number of otherwise attractive models for size control require. Instead, we suggest that there exists a cellular machinery dedicated to flagellar size control and that the short‐flagella mutations alter the machinery in some as yet unknown way. One of the mutants shows temperature‐sensitive flagellar assembly, and both are flagellaless in acetate media. Genetic analysis indicates that the temperaturesensitive, acetate‐sensitive, and short‐flagella phenotypes have a common genetic basis. The responsible gene has been named shf‐1, and it has been mapped to chromosome VI, approximately 5 map units from the centromere.
Scale Formation in an Amoeba, Cochliopodium sp.
Authors: YAMAOKA IKUO , KAWAMURA NOBUYUKI , MIZUNO MANAKO , NAGATANI YOSHIMI 
Published: May 2007

ABSTRACTDuring excystment of an amoeba, Cochliopodium sp., scale formation was examined with light and electron microscopy. This amoeba was covered with scales. When the amoeba encysted, the scales remained on the external surface of the cyst wall. Soon after the induction of excystment the Golgi complex began to develop. Many vesicles were extruded from it and changed into vacuoles. Scales were observed first in the vacuole adjacent to the Golgi complex and later in inside the cyst wall. When the amoeba excysted it had been coated by the newly formed scales. It is suggested that the scale formation is dependent on the activity of the Golgi complex.
Characterization of a Mutant of Toxoplasma gondii Resistant to Aphidicolin1
Authors: PFEFFERKORN E. R. 
Published: May 2007

ABSTRACTAphidicolin, a mycotoxin that inhibits eucaryotic DNA polymerase alpha, blocked the growth of Toxoplasma gondii in confluent cultured human fibroblasts. Aphidicolin immediately inhibited DNA synthesis by T. gondii while it had a delayed and less dramatic effect on RNA synthesis. A mutant of T. gondii resistant to aphidicolin was isolated with the aid of mutagenesis by ethylnitrosourea. Parasite growth measured three days after drug treatment and parasite DNA synthesis measured immediately after drug treatment were, respectively, five‐ and four‐fold more resistant to aphidicolin in the mutant as compared with the wild type parasite. The mutant had a three‐fold greater capacity than the wild type to incorporate uracil into its deoxycytidine triphosphate pool. This increased deoxycytidine triphosphate pool is the probable explanation for the mutant's resistance because this deoxynucleotide is known, in mammalian cells, to reverse the inhibition of DNA synthesis by aphidicolin in a competitive manner.
Eimeria beldingiin. sp. and Other Coccidia (Apicomplexa) of the Ground SquirrelSpermophilus beldingi1
Authors: VELUVOLU PUSHPAVATHY , LEVINE NORMAN D. 
Published: May 2007

ABSTRACTFecal samples of 36 ground squirrels,Spermophilus beldingi, from Tioga Pass (elev. ca. 3315 m) in the Sierra Nevada, California, yielded oocysts ofEimeria beckeriin nine squirrels,E. citelliin four squirrels,E. beldingiin. sp. in two squirrels, and degenerated, unidentifiable oocysts in ten squirrels.Eimeria beldingiin. sp. oocysts are ellipsoidal, 30–34 × 24–30 (mean 32 × 26) μm with a two‐layered, rough, striated wall, without a micropyle or residuum, with polar granules; they contain ellipsoidal or ovoid sporocysts 11–15 × 9–12 (mean 13 × 10) μm with a Stieda body and residuum.
Chemical Induction of Autogamy in Paramecium multimicronucleatum, Syngen 21
Authors: SHIMOMURA FUMIYO , TAKAGI YOSHIOMI 
Published: May 2007

ABSTRACTThe combination of KCl + acriflavine + Ca2+‐poor condition, known as conjugation‐inducing‐chemicals, was found to be autogamy‐inducing‐chemicals as well. Suspension of a single cell of Paramecium multimicronucleatum, syngen 2 in this medium for three hours or more resulted in autogamy that was evidenced by cytological similarity to conjugation.
Detection of Giardia in Sewage Effluent1
Authors: McHARRY MARGARET J. 
Published: May 2007

ABSTRACTGiardia sp. cysts were found at levels of 4,000–450,000/378,500 liters (100,000 gallons) in sewage effluents from three of seven sewage treatment plants in Sangamon County, Illinois, in June, July, and August 1981. Effluent from the positive plants is discharged into Lake Springfield (the present source of the city of Springfield's water supply) or the Sangamon River.
The Effects of Aspirin‐Containing Serum in the Continuous Culture of Plasmodium falciparum1
Authors: WHAUN JUNE M. 
Published: May 2007

ABSTRACTIn vitro culture of Plasmodium falciparum‐infected human erythrocytes (RBC) has permitted systematic study of human host‐parasite relations. In this study the effect of aspirin in the culture system was examined by using serum from blood of fasting, healthy male volunteers, before and after the ingestion of aspirin. The addition of aspirin‐containing serum disturbed parasite growth and development: 0‐1/2 dilutions of treated/control sera inhibited parasite development, with nuclear pyknosis, pyknotic extracellular parasites (trophozoites) in the media, decreased numbers and sizes of “rings” (early trophozoites), and an increased number of later trophozoites and schizonts. Paradoxically, while the incorporation of [3H]isoleucine into protein was not affected by the aspirin‐containing sera, the incorporation [3H]hypoxanthine was significantly changed and did not correlate with morphological evidence of cytotoxicity. Thus, the so‐called “incorporation” of a radioactive tracer is not a fully reliable index of parasite growth in the presence of certain compounds. The findings underscore the importance, in this culture system which employs human serum, of avoiding serum from donors who have recently ingested aspirin.
Trypanosoma cruzi from the Paraguayan Chaco: Isoenzyme Profiles of Strains Isolated at Makthlawaiya1
Authors: CHAPMAN MARTIN D. , BAGGALEY RACHEL C. , GODFREY‐FAUSSET PETER F. , MALPAS TIMOTHY J. , WHITE GENEVIEVE , CANESE JORGE , MILES MICHAEL A. 
Published: May 2007

ABSTRACTAt Makthlawaiya, in the Paraguayan Chaco, the prevalence of Trypanosoma (Schizotrypanum) cruzi infection among both domestic Triatoma infestans and domestic dogs was 38%, and IgG anti‐T. cruzi antibody was detected by the quantitative enzyme‐linked immunosorbent assay (ELISA) in 80% (105/133) of human sera. Ninety percent (25/28) of T. cruzi strains isolated from both T. infestans and dogs showed heterozygous isoenzyme profiles for glucose phosphate isomerase, phosphoglucomutase and 6‐phosphogluconate dehydrogenase. These strains appeared to be closely related to Bolivian zymodeme 2. Three Paraguayan T. cruzi strains showed homozygous isoenzyme profiles, similar to those of major Brazilian zymodemes. It was concluded that T. cruzi strains with heterozygous isoenzyme profiles predominate in domestic transmission cycles in this highly endemic area of the Paraguayan Chaco.
The Surface of the African Trypanosomes1,2
Authors: RICHARDS FRANK F. 
Published: May 2007

ABSTRACTThe African trypanosomes bear on the outside of their cell membrane a single 10–15 nm thick coat of a glycoprotein. This glycoprotein may differ in structure in the predominant populations of parasitemic waves found in relapsing infections. Variant Specific Glycoprotein (VSG) range in MW between 53,000–63,000 d and may have variable amounts of carbohydrate attached at one, two, or several loci. Such differences in carbohydrate content may account in part for their range in molecular size. Approximately 30 C‐terminal residues demonstrate isotypy; i.e. these regions fall into classes having similar amino acid sequence. Modest homology has been demonstrated in two VSGs of T. congolense arising in relapsing infections although comparison of many VSG show little or no obvious homology. More recently, lipid‐associated forms of VSG have been described and it is believed that these forms may be transmembrane proteins. Different VSGs appear to have different amounts of the primary sequence which have alpha‐helix‐forming potential. In some VSG, in excess of 80% of the structure is helical as judged by both Chou‐Fasman calculations and by circular dichroism. This raises the possibility that different VSG may have different folding patterns. The arrangement of VSG on the trypanosome surface probably places the basic amino acid‐rich carbohydrate‐bearing C‐terminus of the polypeptide chain close to the membrane. There is some protein‐protein association between VSGs for which (in T. evansi) the C‐terminal tail is not required. The importance of VSG structure lies not only in the fact that the molecule mediates the phenomenon of antigenic variation but also in the recent observation that VSG may act on the cellular immune system to suppress the humoral immune responses of the host.
Trichodinid Protozoa (Ciliophora: Peritrichida) from Freshwater Fishes of Rybinsk Reservoir, USSR1
Authors: ARTHUR J. R. , LOM J. 
Published: May 2007

ABSTRACTDuring the spring of 1981, trichodinid protozoa were collected from the gills or urinary bladder of the following species of fishes of Rybinsk Reservoir, USSR, located on the upper reaches of the Volga River system: Esox lucius, Rutilus rutilus, Leuciscus idus, Blicca bjoerkna, Abramis ballerus, Pelecus cultratus, Lota lota, and Perca fluviatilis. A total of 13 species of Trichodinidae was recovered from Rybinsk fishes, among which are three new species of the genus Trichodina: T. izyumovae n. sp. from the gills of L. idus, T. borokensis n. sp. from the gills of P. cultratus, and T. kupermani n. sp. from the gills of A. ballerus. Other species of trichodinids reported are T. modesta Lom, 1980; T. nigra Lom, 1969; T. pediculus (O. F. Müller, 1786); T. prowazeki Grupcheva & Lom, 1980; T. rostrata Kulemina, 1968; T. urinaria Dogiel, 1940; T. ophiocephalus Kostenko & Karaev, 1976; Paratrichodina incisa (Lom, 1959); Trichodinella epizootica (Raabe, 1950); and Tripartiella copiosa Lom, 1959. Photomicrographs and morphometric data are presented for each species and aspects of their host and geographic distribution discussed. Trichodina algonquinensis Li & Desser, 1983 is considered a synonym of T. urinaria Dogiel, 1940.
Taxonomy and Review of the Coccidian GenusCryptosporidium(Protozoa, Apicomplexa)1
Authors: LEVINE NORMAN D. 
Published: May 2007

ABSTRACTReports ofCryptosporidiumin various hosts and cross‐transmission experiments are reviewed.Cryptosporidiumhas been found in mammals (Primates, Artiodactyla, Perissodactyla, Carnivora, Lagomorpha, and Rodentia), birds, reptiles, and fish. The only cross‐transmission attempts that have been made have been from mammals to other mammals and to a few birds. Names have been given to 19 “species,” but it is concluded that only four of these should be considered valid at present. These are:C. murisTyzzer, 1907 in mammals,C. meleagridisSlavin, 1955 in birds,C. crotaliTriffit, 1925 in reptiles, andC. nasorumHoover, Hoerr, Carlton, Hinsman & Ferguson, 1981 in fish.
The Morphology of Ovine Trypanosoma melophagium (Zoomastigophorea: Kinetoplastida)1
Authors: BÜSCHER G. , FRIEDHOFF K. T. 
Published: May 2007

ABSTRACTMorphologic and biometric data on bloodstream stages of Trypanosoma melophagium are presented. An increasing parasitemia with 111 trypomastigote stages of T. melophagium were found in Giemsa‐stained thin blood smears taken from a splenectomized, cortisone‐treated sheep recently infested with Melophagus ovinus infected with T. melophagium. The arithmetic mean and standard deviation in μm of the distances between posterior end and kinetoplast were 14.7 and 2.9, from the kinetoplast to the center of the nucleus 5.1 and 1.1, and from there to the anterior end 19.5 and 1.9. The free flagellum measured 6.0 μm ± 1.6 μm. The median and the range of the central 70% of values (median ± 35%) of the nuclear index were 1.1 and 0.9–1.2 and of the kinetoplastic index 3.8 and 3.3–4.9. The same data in μm for the maximal width were 3.1 and 2.1–4.6, and for the width at the level of the nucleus 2.9 and 2.2–4.6. The larger and smaller diameters of the nucleus measured 2.6 (2.2–3.7) μm and 1.7 (1.3–1.7) μm, respectively. The corresponding kinetoplast diameters were 1.1 (0.9–1.3) μm and 0.9 (0.6–0.9) μm, respectively.
Activation of Glycogen Phosphorylase by Cyclic AMP in Tetrahymena pyriformis1
Authors: MUTO YOSHINORI , KUDO SHUZO , NOZAWA YOSHINORI 
Published: May 2007

ABSTRACTGlycogen phosphorylase in Tetrahymena pyriformis was activated by a Mg2+ ATP‐dependent process and this activation was further increased by the addition of cyclic AMP. When the enzyme activity in subcellular fractions was measured, it was largely associated with the glycogen fraction but was no longer activated by ATP and cyclic AMP. Mixing the glycogen fraction and cytosol fraction together restored the effects of ATP and cyclic AMP on phosphorylase activity. These findings suggest that glycogen phosphorylase associated with Tetrahymena glycogen granules may be regulated by cytosolic factor(s) with cyclic AMP.
Development of Second Generation Merozoites of Leucocytozoon caulleryi In Vitro
Authors: ISOBE T. , YAMAGUCHI S. , IMADA T. , KAWAKITA F. , AKIBA K. 
Published: May 2007

ABSTRACTSporozoites of Leucocytozoon caulleryi were inoculated into specific‐pathogen‐free (SPF) chickens intravenously. Fourteen days after inoculation, the infected blood, parasitized with second generation merozoites, was collected from the chickens. The blood was then suspended in SPF chicken serum or RPMI‐1640 culture medium supplemented with 20% SPF chicken serum in petri dishes, which were cultured at 37°C or 41°C in a humidified atmosphere of 5% CO2. Second generation merozoites in parasitized, immature erythrocytes developed continuously through several substages and finally became micro‐ and macro‐gametocytes after 6 days of incubation.
The Catabolism of Tryptophan to Indole‐3‐Ethanol by Crithidia fasciculata and Phytomonas davidi1
Authors: Seed John R. , Hall James Edwin , Sechelski John 
Published: May 2007

ABSTRACTCrithidia fasciculata and Phytomonas davidi catabolize tryptophan (TRP) to indole‐3‐ethanol, which was identified by both thin layer and gas chromatography. The catabolic pathway involved in this metabolic conversion is suggested to be similar to that proposed for other members of the family Trypanosomatidae. Although this catabolism occurs at both 25° and 37°C, the catabolic rate is greater at 37°C, a non‐permissive growth temperature. Conditions that inhibit protein synthesis would appear to favor the catabolism of tryptophan to indole‐3‐ethanol. The possible importance of this catabolic pathway to these organisms is discussed.
Observation on Complete Schizogony of Plasmodium vivax in Vitro1
Authors: Brockelman Chariya R. , Tan‐Ariya Peerapan , Laovanitch Ratchapin 
Published: May 2007

ABSTRACTAttempts to grow Plasmodium vivax in vitro were made on 43 isolates in three different culture media. Complete schizogony occurred in the new medium SCMI 612 in which 34 out of 43 isolates produced merozoites. The RPMI 1640 and Waymouth media suitable for the cultivation of P. falciparum were also used with markedly less success. Results of the experiments indicate differences in nutritional requirements between the two species of Plasmodium.
Trypanosoma cruzi: Biological Characterization of Clones Derived from Chronic Chagasic Patients. II. Quantitative Analysis of the Intracellular Cycle1
Authors: Engel Juan C. , Doyle Patricia S. , Dvorak James A. 
Published: May 2007

ABSTRACTThe complete intracellular cycle of five cloned stocks of Trypanosoma cruzi was quantified. Marked but stable interclonal differences were found in the length of the pre‐replicative lag period (18.2‐34.2 h), amastigote doubling lime (8.6‐21.5 h), and duration of the complete intracellular cycle (96‐215 h). Strong correlations were demonstrated between these characteristics as well as to the growth rate of the epimastigote stage of the same clones grown in liquid medium. These data demonstrate that the marked heterogeneity of the natural population of T. cruzi extends to the intracellular cycle of the parasite and has important implications for our understanding of Chagas’ disease.
Long‐Term Patterns of Protozoan Colonization in Douglas Lake, Michigan
Authors: Pratt James R. , Cairns John 
Published: May 2007

ABSTRACTLong‐term patterns of noninteractive and interactive protozoan colonization of polyurethane foam (PF) artificial substrates in Douglas Lake, Michigan, were examined for a 14‐yr period. Species‐time data were fitted to the Mac Arthur‐Wilson equilibrium model, S =Šeq(1 ‐ eGt), and examined through time from 1969‐1982. Comparisons were made to historical water chemistry measurements. No long‐term changes in water chemistry were evident. Similarly, equilibrium species number (Šeq) and colonization rate (G) oscillated about a mean through time. Protozoan colonization of PF substrates appeared stable for extended periods and showed modest variation from year to year. Examination of 7‐yr‐old substrates in 1982 revealed little difference from young (< 50 days) substrates. Previous reports of senescence of artificial substrate communities may have been due to habitat loss within the substrates. No evidence existed for chemical or biological degradation of the lake.
Electron Microscope Autoradiography of DNA Synthesis in the Replication Band of Two Hypotrichous Ciliates1
Authors: Lin Meiying , Prescott David M. 
Published: May 2007

ABSTRACTThe synthesis of DNA in two hypotrichous ciliates, Styx sp. and an amicronucleated strain of Oxytricha sp., was studied by high voltage (1000 kV) electron microscopy. High voltage EM permits use of thick sections (0.25‐0.40 μm), including serial sections; thick sections produce strong autoradiographic images with relatively short exposure times. The autoradiographs show that DNA synthesis occurs in a narrow part of the rear zone of a replication band in the macronucleus. Macronuclear DNA synthesis occupies a substantial part of the interdivision interval, and micronuclear DNA synthesis in Styx sp. takes place in early prophase at a time when macronuclear DNA synthesis is in its terminal phase.