bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Coccidian Oocyst Populations by Means of Flow Cytometry
Authors: FULLER A. LORRAINE , McDOUGALD L. R. 
Published: May 2007

ABSTRACTFlow cytometry was employed as a tool to analyze and characterize batches of oocysts from laboratory and field isolates of Eimeria spp. from chickens and to propagate sub‐populations of batches of oocysts. Oocyst batches were cleaned of debris by a combination of salt flotation, washing and treatment with dilute sodium hypochlorite (1.5% aqueous). Oocyst size and shape were registered by forward‐angle light scatter with the argon laser excitation set at 488 nm at 300 mW. Sub‐populations of oocysts were collected by map gating and used for microscopy or for propagation. The profile of particle size was characteristic for each species. Propagation of sub‐populations of oocysts of specified sizes resulted in cultures of coccidia that were pure species or nearly pure species. The small size of E. mills caused difficulty in separation from the remaining fine debris. This technique was useful for studying the variation in oocyst size within populations and characterization of field isolates of mixed species. Propagation of pure species from mixed isolates by bit‐map gating had the same limitations as micromanipulation because of the overlapping size of Eimeria spp. Chancaerization is further limited by the lack of suitable size/shape standards for flow cytometry‐Key words. Cell sorter. Eimeria spp., oocyst shape, oocyst size.
Cannibalism and Coprophagy Are Modes of Transmission of Blastocrithidia triatomae (Trypanosomatidae) between Triatomines
Authors: SCHAUB GUNTER A. , BÖKER CORNELIA A. , JENSEN CORD , REDUTH DAGMAR 
Published: May 2007

ABSTRACTTransovarial transmission was not detectable among Blastocrithidia triatomae‐ infected Triatoma infestans. Rather, B. triatomae was transmitted directiy between triatomines by cannibalism and coprophagy. Cannibalism conditions that excluded coprophagy always resulted in an infection of Dipetalogaster maxima. The efficiency of transmission was not influenced by the blood source—mice or chickens—fed to the infected donor bugs although chicken blood lyses the epimastigotes of the stomach population. Triatoma infestans was infected by coprophagy only if fed, not if unfed. Blastocrithidia triatomae in dry feces was taken up only if the feces were redissolved in fresh feces. Infections also appeared in groups of bugs fed on chickens previously used for feeding infected bugs.
Isospora peromysci Davis, 1967 (Apicomplexa: Eimeriidae) in Peromyscus leucopus and P. maniculatus (Rodentia: Cricetidae) from Texas
Authors: McALLISTER CHRIS T. , UPTON STEVE J. 
Published: May 2007

ABSTRACTOocysts of Isospora peromysci (Davis, 1967) (Apicomplexa: Eimeriidae) were recovered from the feces of 1/30 (3.3%) white‐footed mice, Peromyscus leucopus, in Johnson County, Texas. This report represents a new host and geographic record for the parasite. The coccidium was also found in 1/20 (5.0%) deer mice, P. maniculatus, from the same locale. Morphological data are provided on the sporulated oocyst of I. peromysci and comparisons are made with previously published information on the species from other geographic localities.
Metabolic Interactions Between Glucose, Glycerol, Alanine and Acetate in Leishmania braziliensis panamensis Promastigotes
Authors: DARLING T. N. , DAVIS D. G. , LONDON R. E. , BLUM J. J. 
Published: May 2007

ABSTRACT13C‐nuciear magnetic resonance (NMR) spectroscopy was used to investigate the products of glycerol and acetate metabolism released by Leishmania braziliensis panamensis promastigotes and also to examine the interaction of each of these substrates with glucose or alanine. The NMR data were supplemented by measurements of the rates of oxygen consumption and substrate utilization, and of 14CO2 production from 14C‐labeIed substrate. Cells incubated with [2‐13C]glycerol released acetate, succinate and D‐lactate in addition to CO2. Cells incubated with acetate released only CO2. More succinate C‐2/C‐3 than C‐l/C‐4 was released from both [2‐13C]glycerol and [2‐13C]glucose, indicating that succinate was formed predominantly by CO2 fixation followed by reverse flux through part of the Krebs cycle. Some redistribution of the position of labeling was also seen in alanine and pyruvate, suggesting cycling through pyruvate/oxaloacetate/phosphoenolpyruvate. Cells incubated with combinations of 2 substrates consumed oxygen at the same rate as cells incubated with 1 or no substrate, even though the total substrate utilization had increased. When promastigotes were incubated with both glycerol and glucose, the rate of glucose consumption was unchanged but glycerol consumption decreased about 50%, and the rate of 14CO2 production from [l,(3)‐14C]glycerol decreased about 60%. Alanine did not affect the rates of consumption of glucose or glycerol, but decreased 14CO2 production from these substrates by increasing flow of label into alanine. Although glucose decreased alanine consumption by 70%, it increased the rate of 14CO2 production from [U‐14C]‐ and [l‐14C]alanine by about 20%. This is consistent with rapid equilibration of alanine with pyruvate derived from glucose and yet little decrease in the specific activity of the large alanine pool.
Plasmodium falciparum Gametocyte Formation In Vitro: Its Stimulation by Phorbol Diesters and by 8‐Bromo Cyclic Adenosine Monophosphateau WILLIAM TRAGER
Authors: GILL GOKAL S. 
Published: May 2007

ABSTRACT. Phorbol 12‐myristate 13‐acetate increased the number of gametocytes by 50 to 100% in well or petri dish cultures of the HB‐3 clone of Plasmodium falciparum. Phorbol dibutyrate had a similar effect. The optimal concentration for each of these agents was 20 ng/ml or approximately 30 nM. No effect of forskolin was found, other than a general inhibition of growth at concentrations over 10 μM. An inhibitor of phosphodiesterase, 8‐bromo cyclic adenosine monophosphate (at concentrations of 0.1 and 1.0 μM) also significantly increased the number of gametocytes formed by this clone.
Circular DNA of Entamoeba histolytica Encodes Ribosomal RNA
Authors: BHATTACHARYA SUDHA , BHATTACHARYA ALOK , DIAMOND LOUIS S. , SOLDO ANTHONY T. 
Published: May 2007

ABSTRACT. The presence of repeated DNA sequences encoding RNA in Entamoeba histolytica has been reported. In the present study we demonstrate by agarose gel electrophoresis, DNase digestion and electron microscopic analysis that these genes are located on extrachromosomal circular DNA molecules with an approximate size of 26 kb. Detection of replication intermediates suggests the episomal nature of these molecules.Amplified, extrachromosomal rRNA genes appear to be a common feature among the lower eukaryotes, occurring more commonly as linear molecules and less commonly as circles. Entamoeba histolytica is 1 of the few organisms studied in which rRNA genes are located predominantly on extrachromosomal circles.
Cellular Behaviour Modulated by Ions: Electrophysiological Implications
Authors: MACHEMER HANS 
Published: May 2007

ABSTRACT. This essay considers the responses of Paramecium and other ciliates to the inorganic ion environment from an elec‐trophysiological point of view. In reviewing data from published and unpublished sources it is shown that ions affect the cellular behaviour in multiple ways because the transmembrane potential can change due to the alteration of equilibrium potentials, ion conductances and surface charges of the membrane. Sensory input including effects from the ionic environment converge upon the membrane potential which has a temporal and spatial summing function. Hyperpolarizing and depolarizing potential shifts from the set point are near‐simultaneously and omnidirectionally transmitted along the membrane including the ciliary boundaries. The membrane potential regulates ciliary motility via an intraciliary messenger, Ca2+, which can enter, and presumably leave, the cytosol directly adjacent to the ciliary motor. Integration of the responses of thousands of cilia occurs in accordance with the electrical and structural provisions of the cell. Potential‐regulated motor and behavioural responses attenuate with time. This phenomenon, which has been loosely termed adaptation, has an electrophysiological basis in analogy to membrane accommodation following sustained stimulus input. The mechanisms of adaptation serve to restore, in principle, the membrane resting state and, thereby, the sensitivity to depolarizing and hyperpolarizing shifts of the membrane potential and the cell's responsiveness to environmental stimuli, respectively. For the inorganic ions involved in chemosensation the terms attractant and repellent are not applicable. They should be reserved to signalling substances which per se can define the behaviour of the cell.
Ultrastructure of Sporozoites and Zoites of Hammondia heydorni
Authors: SPEER C. A. , DUBEY J. P. 
Published: May 2007

ABSTRACTThe ultrastructure of sporozoites and zoites of Hammondia heydorni was studied in cultured bovine cells. In addition to ultrastructural features typical of coccidian parasites, H. heydorni sporozoites and zoites contain rhoptries that are located posteriorly as well as anteriorly. Also, sporozoites contain a posteriorly located crystalloid body (1.2 μm in diameter); a small crystalloid body (0.5 μm in diameter) was occasionally seen in the anterior end. Zoites resulting from the 1st division of endodyogeny contain a posteriorly located crystalloid body, which is absent in zoites formed by subsequent divisions. Zoites contain posteriorly located amylopectin granules and a relatively large anterior vacuole which is not present in sporozoites. During penetration, the host cell plasmalemma ballooned laterally around the sporozoite creating a large cavity, which later disappeared. Sporozoites and zoites undergoing cell penetration usually exhibit partially empty anterior rhoptries; no changes occur in posterior rhoptries. Lysosomes fuse with the par‐asitophorous vacuole surrounding killed sporozoites but not live sporozoites.
In Vitro Killing of Babesia bovis by the Ornithine Analog α‐monofluoromethyldehydroornithine Methyl Ester
Authors: JASMER DOUGLAS P. , GOFF WILL L. 
Published: May 2007

ABSTRACTThe effects of the 2 ornithine decarboxylase inhibitors α‐difluoromethylomithine (DFMO) and α‐monofluoromethyl‐dehydroormithine methyl ester (ΔMFMO‐ME) on growth ofBabesia bovis blood stages in vitro were tested. The DFMO had no apparent effects on in vitro growth of B. bovis nor on the morphology of the parasite at concentrations up to 20 mM. In contrast, ΔMFMO‐ME had cytotoxic effects on B. bovis at 0.5 mM which were more pronounced at 5 mM. ΔMFMO‐ME caused both a decrease in percentage parasitized erythrocytes and a degeneration of parasites after 12 h exposure, and the magnitude of both effects was dose‐dependent. The effects of ΔMFMO‐ME were not reversible for B. bovis precultured for 12 h (5 mM) or 24 h (0.5 mM) in drug before culturing the parasite in drug‐free medium. Unexpectedly, 300 μM putrescine did not reverse the effects of ΔMFMO‐ME on B. bovis blood stage, raising the possibility that inhibition of omithine decarboxylase is not responsible for these effects.
Substrates Determine Spatial Distribution of Oxytricha bifaria (Ciliata Hypotrichida)
Authors: RICCI NICOLA , ERRA FABRIZIO , RUSSO ANTONINO , BANCHETTI ROSALBA 
Published: May 2007

ABSTRACTThe extent to which a particular substrate (scratched glass) affects the distribution of a population (Oxytricha bifaria) that settled on it was measured, yielding the following results: (1) the species distinguishes among substrates slightly differing in the quality of their superficial scratches (average dimensions of 2, 2.8, 3.5, 6.5, 17 and 25 μm, respectively); (2) it “chooses” the preferred substrate by adopting specific differential behaviors; and (3) population cell density conditions its overall distribution.
Oral Assembly in Left‐Handed Tetrahymena thermophila
Authors: NELSEN E. MARLO , FRANKEL JOSEPH , WILLIAMS NORMAN E. 
Published: May 2007

ABSTRACTWe have investigated oral development in a non‐genically derived left‐handed (LH) form of Tetrahymena thermophila, in which the large‐scale asymmetry of arrangement of cortical structures is reversed whereas the local asymmetry of ciliary architecture remains normal. Approximately 1/2 of the oral apparatuses (OAs) of LH cells develop in the form of superficial mirror‐images of OAs of RH cells. In most of these OAs, membranelles are assembled from the cells’anterior to posterior. Nonetheless, the posterior ends of these membranelles undergo the basal body displacements that lead to a “sculptured” appearance, so that the membranelles of LH OAs become organized as rotational permutations of membranelles of normal RH OAs. Many of these membranelles re‐orient to a normal orientation near the end of oral development. Membranelles and undulating membranes (UMs) may develop independently of each other, and formation of postciliary microtubules of UMs is separate from that of ribbed wall microtubules. In some cases, the entire OA develops and remains as a 180° rotational permutation of the normal, resembling the inverted OAs of mirror‐image doublets and LH cells of Glaucoma scintillans described by Suhama [36, 37]. We present a model (Fig. 37) for these complex developmental outcomes. These developmental patterns resemble those described previously and less completely for “secondary” OAs of cells with mirror‐image global patterns, including janus cells. The present study demonstrates that such alterations in oral development are not a direct outcome of genotypic changes.
Studies on the Attachment of Leishmania Flagella to Sand Fly Midgut Epithelium
Authors: WARBURG ALON , TESH ROBERT B. , McMAHON‐PRATT DIANE 
Published: May 2007

ABSTRACTAn in vitro assay was developed to study the recognition mechanism for attachment of Leishmania flagella to sand fly midgut epithelium. Frozen sections of sand fly guts were incubated with Hagella preparations, and probed with a flagella‐specific monoclonal antibody. Tissue‐specific adhesion of flagella to midgut epithelium was demonstrated by indirect immunofluorescence. None of the 13 sugars, screened to test for possible lectin‐mediation, appeared to significantly inhibit the adhesion of flagella to gut sections. Similarly no inhibition was achieved by incubating flagella with pep 63 which inhibits the promastigote‐macrophage recognition mechanism. Significant inhibition was attained by incubating flagella preparations with a monoclonal antibody which binds to a flagellar membrane‐component. The possible relevance of the described mechanism for the biology of Leishmania in their sand fly hosts, is discussed.
Structure of Major Surface Determinants and DNA Diagnosis of Pneumocystis carinii
Authors: NAKAMURA YOSHIKAZU , TANABE KIYOKATSU , EGAWA KOHJI 
Published: May 2007

ABSTRACTPneumocystis carinii is a pathogen which causes fatal pneumonia in patients with the acquired immune deficiency syndrome (AIDS). To facilitate the basic study of P. carinii, wc have analyzed its major surface proteins by both immunochemical and biochemical methods. The major protein components of both cysts and trophozoites are a group of proteins called “PI 15” with apparent masses of 105–120 kd. It includes 6 isoelectric variants. A monoclonal antibody raised against cysts recognizes all 6 variants and reacts with epitopes located in the cell wall indicating that PI 15 is an immunoreactive surface component. The isoelectric variants contain identical or closely related protein components and they are mannose‐rich glycoproteins. The isoelectric variation may be due primarily to differences in glycosylation. The majority of sera from humans with diagnosed pneumocystosis that were tested reacted strongly with the PI 15 proteins. To develop probes for DNA diagnosis and to facilitate molecular studies, a genomic DNA library of P. carinii has been constructed. Some of these clones were used for DNA hybridization analysis of rat and human lungs.
Methods for Inducing Selfing, Selfing and Its Role in the Life Cycle of Euplotes woodruffi syngen 3 (Ciliophora)
Authors: KOSAKA TOSHIKAZU 
Published: May 2007

ABSTRACTMethods for inducing selfing, and the relation between selfing and the life cycle of Euplotes woodruffi syngen 3 are reported. Three intercrossing stocks were used in this experiment. Selfing was induced with several treatments as follows: cell‐free fluid from the cultures of complementary mating types; intact cells of GI or S phase in the cell cycle; heat‐killed cells, and lysed cells of GI‐, S‐, and D‐phase cells which were prepared by freeze‐thawing. Stock SJ‐27 was used as a parental stock from which Fl clones were originated through selfing. The other two stocks, SJ‐8 and SJ‐19, were used as testers. The period of immaturity varied from clone to clone. The heterotypic conjugation of clones with cells of stock SJ‐8 seems to occur earlier in the life cycle than with cells of stock SJ‐19. This result shows that this syngen has an adolescent period in the life cycle. The length of selfing immaturity seems to be different from that of crossing immaturity, and selfing appeared slightly later than crossing with testers. But the clones in which selfing 1st occurred are considered to be in adolescence or maturity, not in senility. Once selfing appeared in any clone, the clone continued to produce selfing pairs till just before clonal death. The viability of selfing and of outcrossing were compared and found not significantly different. Inbreeding depression took place in some of the F2 clones by successive selfing. The viability of F2 clones from young parents was significantly higher than that from old parents (220 to 230 fissions) both in selfing and outcrossing. The total life spans which were studied in three F1 clones were 168 to 264 fissions.
Ortholinea alata n. sp. (Myxosporea: Ortholineidae) in the Northern Butterfly Fish Chaetodon rainfordi
Authors: KENT MICHAEL L. , MOSER MIKE 
Published: May 2007

ABSTRACTOrtholinea alata n. sp. is described from the northern butterfly fish, Chaetodon rainfordi collected at Heron Island, Great Barrier Reef, Australia. Spherical, disporous trophozoites (10–15 μ) and spores were observed in the lumina of kidney tubules and collecting ducts. Spores are broadly triangular with two short, broad processes that extend dorsoventrad from the posterior end of each of the two spore valves. Valves are bisected by a suture in the plane of the polar capsules. Spores are 12.6 μ (length) × 9.6 μ (width) × 9.9 μ (length), and at the anterior end contain two spherical, divergent polar capsules measuring 4.6 (4.1–5.1) μ. Sporogenesis is similar to that of renal Sphaerospora spp.: the intraluminal trophozoites of O. alata n. sp. correspond to pseudoplasmodia described for Sphaerospora spp. and no large, multinucleate plasmodia are formed. No significant histopathological changes were observed in the kidneys of infected fish.
Antimalarial Properties of Imipramine and Amitriptyline12
Authors: DUTTA PURABI , PINTO JOHN , RIVLIN RICHARD 
Published: May 2007

ABSTRACTDietary riboflavin deficiency is known to diminish malarial parasitemia. In this study, we determined whether imipramine and amitriptyline, drugs which inhibit riboflavin metabolism, have antimalarial efficacy. In addition, we evaluated whether these drugs, like other antimalarial agents, increase the hemolytic response to ferriprotoporphyrin IX (FP). The growth of Plasmodium falciparum (FCR3) in the absence and presence of these drugs (10 to 75 μM) was measured by determining (3H)hypoxanthine uptake by intraerythrocytic parasites for 48 h in RPMI 1640 medium. The uptake of (3H)hypoxanthine was significantly reduced in a dose‐dependent manner by both imipramine and amitriptyline. The IC50 values of imipramine and amitriptyline at 48 h were 56 and 45 μM, respectively. Both drugs enhanced hemolysis induced by FP (10 or 20 μM). No hemolysis by these drugs was detected in the absence of FP. It is concluded that the tricyclic antidepressants, imipramine and amitriptyline, possess substantial antimalarial properties.
Influence of Host Diet on the Fatty Acid Composition and Content of Rumen Protozoa in Cattle
Authors: O'KELLY JOHN C. , SPIERS WILLIAM G. 
Published: May 2007

ABSTRACTThe fatty acid profiles and contents of protozoa from the rumen fluid of cattle varied according to the type of diet consumed by their host. Changing from a high‐quality hay diet to a low‐quality hay diet (DA) decreased the proportions of saturated acids and increased the proportions of the unsaturated acids 18:1 cis‐9, 18:2 and 18:3 in neutral lipids (NL) and phospholipids (PL). Adding sucrose, urea and sulphur (SUS) to DA increased the proportions of branched chain acids in PL while addition of safflower oil increased polyunsaturated acids in PL and 18:1 trans‐11 in NL. Diet did not alter the PL fatty acid content of protozoa but oil supplement of DA resulted in a 10‐fold increase in the content of free fatty acids. The defaunating effect of oil supplement was partly reversed by SUS suggesting that factors other than the fatty acid content of cells are important in determining the toxicity of oil to rumen protozoa. The results indicate that the amounts of individual long‐chain fatty acids taken up by rumen ciliates are largely determined by their concentrations in rumen digesta.
The Effect of Ultraviolet Radiation on the Germination of Nosema algerae Vávra and Undeen (Microsporida: Nosematidae) Spores1
Authors: UNDEEN ALBERT H. , MEER ROBERT K. VANDER 
Published: May 2007

ABSTRACTSpores of Nosema algerae Vávra and Undeen were subjected to various dosages of 254 nm ultraviolet radiation (UV). Very high dosages of UV were required to block germination. Germination was normal immediately after UV dosages of 0.2 to 1.0 J/cm2, followed by a delayed effect in which both percentage germination and the intrasporal concentration of trehalose decreased with time after UV exposure. Although a few spores were germinated, most of them were inactivated (rendered temporarily unable to germinate) by exposure to UV of 1.1 J/cm2. Ultraviolet radiation between 1.1 and 3.4 J/cm2 stimulated spores to germinate. However, spores were completely unable to germinate immediately after exposure to dosages above 3.8 J/cm2. Ammonia had little effect on stimulation by UV but was inhibitory to germination after stimulation had occurred. These results demonstrate that UV behaves like a germination stimulus and are discussed in terms of the hypothesis that germination is initiated by the breakdown of barriers between trehalose and trehalase.
The Plasma Membrane of Myxosporidian Valve Cells: Freeze Fracture Data
Authors: DESPORTES‐LIVAGE ISABELLE , NICOLAS GISELE 
Published: May 2007

ABSTRACTFreeze fracturing of Myxosporidian spores reveals the occurrence of a continuous layer of transmembrane particles all over the surface area of the valve cells which form the spore envelope. These particles are densely packed all over the P face membrane. Due to their polygonal outline, their diameter (6‐7 nm) and their central core, they resemble the particles forming the connections of gap junctions which metabolically couple the neighboring cells in animal tissues. In the present report, the role of the transmembrane particles is still hypothetical. However, they might represent a membrane structural specialization of the spores which are submitted to osmotic variations of the fluid external medium. Furthermore similar transmembrane particles are observed at the level of the septate junction which seals the valve cells. In this occurrence, they are arranged in a series of 40 double rows parallel to the suture of the spore envelope. These findings support the view that Myxosporidia are Metazoa and raise the problem of their origin.