bluuebunny/crossref_metadata_2025_split huggingface dataset:
Attenuation of Parasite cAMP Levels in T. cruzi‐Host Cell Membrane Interactions In Vitro
Authors: VON KREUTER BETSY F. , WALTON BETH L. , SANTOS‐BUCH CHARLES A. 
Published: May 2007

ABSTRACTPrevious investigations have shown that the adhesion of T. cruzi plasma membrane vesicles (PMV) to monolayers of host cell myoblasts and to immobilized heart muscle sarcolemma membranes (PAM) on polyaerylamide beads is mediated by the interaction of T. cruzi attachment sites with the muscarinic cholinergic and β‐adrenergic receptors of the host cell membrane. It has also been shown that this interaction is blunted by the specific antagonists of the mammalian receptors atropine and propranol, respectively. In the studies reported here, PAM also rapidly attached to swimming T. cruzi trypomastigotes in a complex, concentration‐dependent fashion and binding isotherms showed that the equilibrium between free and bound PAM is rapidly reached within 2 minutes of incubation in physiologically balanced salt solutions. In this time frame, trypomastigote cAMP levels are significantly reduced from steady state values within 30 seconds of the addition of PAM in a buffer system containing a diesterase inhibitor. Maximal attenuation of cAMP levels was measured between 1 and 2 minutes of the addition of PAM to T. cruzi trypomastigotes. The degree of cAMP level attenuation was reduced by blocking PAM attachment with either atropine or propranol. On the basis of these results we propose that a likely pathway for the negative parasite signal generated upon adhesion of host muscle cell membranes to the surface of the flagellates is from the parasite's surface attachment sites directly to a Pertussis toxin sensitive inhibitory protein Gi, thereby blunting adenyl cyclase activity and cAMP formation.
Circular rDNA Replicons Persist in Tetrahymena thermophila Transformants Synthesizing GGGGTC Telomeric Repeats
Authors: ROMERO DANIEL P. , BLACKBURN ELIZABETH H. 
Published: May 2007

ABSTRACTSite‐directed mutagenesis of the telomerase RNA from Tetrahymena thermophila was used previously to demonstrate the templating function of a sequence within this RNA; this sequence specifies the sequence of telomeric DNA in vivo. The possible functional importance of a phylogenetically conserved nucleotide outside the telomerase RNA template region was investigated by a similar experimental approach. The telomerase RNA gene was altered by site‐directed mutagenesis, cloned in a circular selectable transformation vector consisting of an rRNA gene carrying a selectable drug resistance marker, and introduced into macronuclei of vegetatively dividing Tetrahymena thermophila by microinjection. Changing an invariant A to U at position 16 of the telomerase RNA (A16U) had no effect detectable by phenotype on telomerase function in vivo. However these experiments showed that a telomerase template alteration that dictates the synthesis of the mutant telomeric DNA sequence GGGGTC leads to a profound change in the population of rDNA replicons. The addition of GGGGTC mutant repeats leads to selective pressure for the loss of high copy linear rDNA, and the rRNA genes are maintained in the form of the circular rDNA replicons introduced during transformation.
Histochemical Detection of Carbohydrates of Blastocystis hominis
Authors: YOSHIKAWA HISAO , KUWAYAMA NOBUKO , ENOSE YOSHIMI 
Published: May 2007

ABSTRACTThe carbohydrates of Blastocystis hominis were detected by histochemical techniques using light and electron microscopy. B. hominis, fixed with various fixatives, followed by treatment with detergents, were stained with periodic acid‐Schiff (PAS) or alcian blue (AB). Intense PAS reactions were observed in cells fixed with glutaraldehyde or 1/2 Karnovsky fixative. The cells fixed with other fixatives showed weak or no reactions with PAS staining. Similar results were seen in the case of AB stain. These results indicated that, depending on the fixative used, B. hominis contained PAS‐ or AB‐reactive carbohydrates. At the electron microscopic level, ultrathin sections of B. hominis were stained with periodic acid methenamine silver (PA‐MS) or periodic acid thiocarbohydrazide‐silver proteinate (PA‐TCH‐SP) staining techniques. Intense, positive reactions with PA‐MS or PA‐TCH‐SP were observed on the central vacuole, Golgi apparatus, and cytoplasmic vesicles. The filamentous layer showed moderate reactions with PA‐MS, whereas in PA‐TCH‐SP stain, it was stained more densely. The staining intensity of the central vacuole varied from cell to cell. The presence of membrane fusions of the cytoplasmic vesicles with the central vacuole indicated the accumulation of carbohydrates in the central vacuole.
Commitment to Division in Ciliate Cell Cycles
Authors: ADL SINA M. , BERGER JAMES D. 
Published: May 2007

ABSTRACTNear the end of the cell cycle, ciliates commit irreversibly to cell division. The point of commitment occurs at the time of oral polykinetid assembly and micronuclear anaphase. The commitment is a checkpoint which requisites a threshold cell mass/ DNA ratio and stomatogenesis. It is also a physiological transition point, involving cdk protein kinases similar to those of other eukaryotes. Both P34 kD and P36 kD kinases, similar to the S. pombe cdc2 kinases, have been described to have activity as monomers. Subsequent to commitment to division, dramatic cytoskeletal modifications occur for separation of organelles, cortex morphogenesis and cytokinesis. Numerous mutants affecting cytoskeletal function associated with the division process have been obtained in several species. Of these, only the ccl mutant in Paramecium affects cell cycle progression prior to commitment to division. The material reviewed is used to speculate about the mechanisms of regulation of pre‐fission morphogenesis and cell division related processes in ciliates.
Stomatogenesis in Kyaroikeus cetarius (Dysteriina, Kyaroikeidae, N. Fam.): Clues to Its Systematic Placement
Authors: SNIEZEK JAMES H. , COATS D. WAYNE 
Published: May 2007

ABSTRACTMorphogenesis in Kyaroikeus cetarius, a large phyllopharyngean parasite of odontocete Cetacea, begins with the midventral proliferation of four short rows of kinetosomes immediately to the left of four pre‐existing, somatic kinetofragments. The resulting field of eight short kineties is located within a shallow depression that gradually elongates and deepens to form the oral cavity of the opisthe. The four right‐most of these kineties sink into the developing oral cavity and divide transversely, producing three distinct sets of kinetofragments. The anterior and posterior sets each consist of four small fragments and ultimately produce the mid‐ventral, somatic kinetofragments of the proter and the opisthe, respectively. In addition, some kinetosomes from the anterior set give rise to the secretory organelle complex of the proter. The central group consists of two long and one short kinetofragment, which represent anlagen for the opisthe circumoral and preoral kineties, respectively. These anlagen migrate progressively anteriad while undergoing a pronounced counterclockwise rotation that eventually inverts the developing oral kineties. Simultaneously, two broad sheets of microtubules, one beneath each circumoral anlage, extend deep into the cytoplasm and unite to line the cytopharynx of the opisthe. Meanwhile, the remainder of the eight original kinetofragments move laterally out of the ventral depression to produce the left ciliary field of the opisthe. Morphogenetic events observed in K. cetarius are typical of cyrtophorid Phyllopharyngia and support inclusion of this genus within suborder Dysteriina.
Ca2+‐Dependence of Conoid Extrusion in Toxoplasma gondii Tachyzoites
Authors: MONDRAGON RICARDO , FRIXIONE EUGENIO 
Published: May 2007

ABSTRACTThe role of Ca2+ in conoid extrusion was investigated in isolated Toxoplasma gondii tachyzoites by treatment with Ca2+‐ionophores, Ca2+‐chelating agents and an inhibitor of the Ca2+‐ATPase at the endoplasmic reticulum. The results were evaluated by light phase‐contrast microscopy and electron microscopy. lonomycin (0.5‐1 μM) caused an immediate and sustained extrusion of the conoid in up to 80% of the tachyzoites, depending on the concentrations of ionophore and Ca2+ in the medium. However, over 50% of the tachyzoites extruded the conoid when treated with ionomycin in Ca2+‐free saline complemented with EGTA. The effect of ionomycin was reversible and could be induced a second time in about half of the responsive population. Similar results were obtained with A23187. Conoid extrusion induced by ionomycin in Ca2+‐free medium was almost completely abolished when the tachyzoites were previously loaded with a permeable compound known to chelate intracellular Ca2+ (BAPTA/AM; 25μM). On the other hand, exposure of tachyzoites to the Ca2+‐ATPase inhibitor thapsigargin (0.5‐1μM) produced significant extrusion of the conoid. Tachyzoites loaded with BAPTA/AM as well as those treated with ionomycin, i.e. with conoids paralyzed in opposite positions, had a diminished capacity to invade cultured epithelial cells. A substantial reduction in the response to stimulation by ionomycin was found also in parasites treated with cytochalasin‐D, a drug that depolymerizes actin‐filaments. The results suggest that Ca2+‐release from internal stores may act as a key signal to activate a mechanism of conoid extrusion probably mediated, at least in part, by actin‐filaments.
Induction of Blocks in Nuclear Divisions and Overcondensation of Meiotic Chromosomes with Cycloheximide During Conjugation of Tetrahymena thermophila
Authors: KACZANOWSKI ANDRZEJ , KACZANOWSKA JANINA 
Published: May 2007

ABSTRACTDuring conjugation, the micronucleus of Tetrahymena thermophila undergoes five consecutive nuclear divisions: meiosis, third prezygotic division (pregamic mitosis) and two postzygotic mitoses of the synkaryon. The four products of the synkaryon differentiate into macronuclear anlagen and new micronuclei and the old macronucleus is resorbed. The protein synthesis inhibitor cycloheximide, applied during conjugation, induced several developmental blocks. Pairs shifted to the drug during early meiotic prophase (stages I–III) were arrested at prophase. Cycloheximide applied to cells at pachytene (stages IV‐VI) to metaphase arrested the conjugants at the stage of modified prometaphase/metaphase with overcondensed, swollen bivalents. In contrast to other systems, in the presence of cycloheximide, separation of chromatids, decondensation of chromosomes and exit from metaphase I were inhibited in both diploid and haploid cells. Pairs shifted to the drug after metaphase I were arrested at postmeiotic interphase after completing one nuclear cycle. The same rule applied to the subsequent cycle; then cells were arrested at the stage of pronuclei, and those pairs with functional pronuclei and synkarya were arrested at the stage of two products of the first postzygotic division (pronuclei were not arrested in nuclear transfer and karyogamy). Only pairs with two products of the first postzygotic division were arrested at the same stage after the cycloheximide treatment. Pairs shifted to cycloheximide during the second postzygotic division were arrested in development of macronuclear anlagen and resorption of old macronuclei. The postmeiotic conjugants pulse‐treated with cycloheximide (2 h) yielded heterokaryons retaining parental macronuclei (i.e. they exhibited macronuclear retention).
Micronuclear and Macronuclear Sequences of a Euplotes crassus Gene Encoding a Putative Nuclear Protein Kinase
Authors: HALE CYNTHIA A. , JACOBS MARY ELLEN , ESTES HEATHER G. , GHOSH SUSMITA , KLOBUTCHER LAWRENCE A. 
Published: May 2007

ABSTRACTThe sequences of a 1.8‐kbp macronuclear DNA molecule (V3), and the majority of its micronuclear counterpart, are reported. The macronuclear V3 DNA molecule contains an open reading frame that is interrupted by a single intron, while the micronuclear copy is interrupted by four internal eliminated sequences, one of which is located within the intron. The predicted protein product of the macronuclear V3 gene is a 471‐amino acid polypeptide that is very similar to a group of protein‐serine/threonine kinases from both plant and animal species, some of whose members appear to be involved in cell cycle or growth control.
Comments: Overveiw of the 5th International Workshop on Pneumocystic and the 5th General Meeting of the European Concerted Action of Pneumocystis Research
Authors: KANESHIRO EDNA S. , WAZLZER PETER D. 
Published: May 2007

SUMMARYThe major highlights of the meetings were the initiation of efforts ot assign different species names to certain Penumocystis jorganism, and the invitations for international participation in a project to map and sequence the genome of P. carinii. The oral and poster presentations demostrated important advances have been achieved in the past year.
Apical Feeding in the Karyorelictids (Protozoa, Ciliophora) Sultanophrys arabica and Tracheloraphis sp.
Authors: AL‐RASHEID KHALED A. S. , FOISSNER WILHELM 
Published: May 2007

ABSTRACT Sultanophrys arabica and Tracheloraphis sp., two interstitial karyorelictid ciliates, were cultivated in sealed 100–200 ml glass bottles half‐filled with filtered interstitial water to which some millilitres of the natural organism community and a couple of wheat grains were added. Removing sand grains and sealing the bottles were crucial to achieve a low oxygen tension milieu, which was maintained by the algae contained in the community. This cultivation method provided, for the first time, rich cultures with many feeding, dividing, and conjugating cells. Both species were omnivorous and fed through the apical end, where a well‐developed oral apparatus is present. Apical feeding was documented by micrographs of living specimens and by scanning electron microscopy of preserved cells.
American Women Writers and the First World War
Authors: Nolan Elizabeth 
Published: May 2007

AbstractTraditionally, the literary representation of the First World War has been the preserve of the male author. In particular, it is the account of the combat experienced soldier, most often the English soldier poets, which has been privileged. For more than two decades, however, critics have been actively engaged in establishing a more inclusive canon of war literature along gendered and national lines. Feminist scholars, in particular, have vigorously explored the complex intersection between war, writing and gender, recovering and re‐evaluating women's narratives of war, recognising them as important literary, social and historical documents. This article will address both gendered and national concerns, offering an overview of important developments in the study of American women's writings from the First World War. It will also engage with current critical debates which address issues such as the development of distinctly female modernisms and the presentation of war through the female gaze.
Reading Shakespearean Violence
Authors: Paul J. Gavin 
Published: May 2007

AbstractThis essay won the 2006Literature CompassGraduate Essay Prize, Shakespeare Section.This article takes as its starting point some of ways in which the events of 9/11 have been integrated into recent critical studies of Shakespeare. These linkages between Shakespeare and 9/11 are a reminder that acts of violence are readily available access points at which to engage with Shakespeare's textual and theatrical manifestations; it is also apparent that broad and contentious issues coalesce around examinations of Shakespeare and violence: authorship, human agency, ideology, the historicizing and politicization of events and texts. With this in mind, it seems a suitable moment for retrospection, to survey prominent voices of the twentieth century in an effort to gain perspective and context for critical interrogations of Shakespeare and violence. This article aims to read critics reading Shakespearean violence in order to identify and examine influential approaches to Shakespeare as well as prominent theoretical modes – Formalism, New Historicism, Cultural Materialism – brought to bear on early modern drama generally.
Exodusas Travelling Theory: Excavating the Promised Land in the African American Imagination
Authors: Hartnell Anna 
Published: May 2007

AbstractThis essay won the 2006 Literature Compass Graduate Essay Prize, American Section.Exodus, this article suggests, is one of the defining texts through which Americans have imaginatively re‐mapped the nation's relationship to the spectre of ‘Egyptian’ oppression. This article proposes to consider the evolution of theExodustext from its pivotal place in an often imperialist presidential rhetoric to its central position in African American elaborations of resistance. I suggest that the story ofExodusissuing from the lips of W. E. B. Du Bois, Martin Luther King or Toni Morrison crucially unsettles the ‘innocent’ position assumed by America's political establishment in relation to the enigmatic question of ‘freedom’. This article reviews the interruptive possibilities of African American re‐tellings of theExodusnarrative in the context of Edward Said's notion of ‘travelling theory’. In his examination of theories devolved from their point of origin, Said poses a crucial distinction between theories that lose their critical power via domestication to the status quo and those which ‘flame out’ from this path by reaffirming and even furthering their radical potential. I argue here that it is these destablizing currents that largely animate the African American counter‐cultural tradition that excavates the promised land in order to tell of a fundamentally ‘unhomely’ exodus. Where mainstream invocations ofExoduspresent America's rendition as an epochal overcoming of Hegel's seemingly inexorable master/slave dialectic, the appropriation of this story by America's internal ‘others’ is a standing reminder that America is not – contra Hegel's memorable suggestion – the destination of ‘History's’ end.
Do family members interfere in the delivery of care when present during invasive paediatric procedures in the emergency department?
Authors: Ryan Glenn , Treston Greg 
Published: May 2007

AbstractObjective:  To determine whether family members interfere with patient care when present during invasive procedures performed on their children in the ED.Methods:  A prospective observational study of consecutive cases of procedural sedation of children aged between 12 months and 16 years was conducted between March 2002 and March 2006 in the ED of a secondary‐level regional hospital in south‐east Queensland. Procedures performed included laceration repair, fracture reduction, foreign body removal and abscess incision and drainage. Parents/primary caregivers were encouraged to stay with their child. A stepwise explanation of the procedure and sedation to be used was undertaken, informed consent obtained and telephone follow up attempted 5–14 days post procedure.Results:  Six hundred and fifty‐two patient encounters with parents or primary caregivers present for the procedure were included for a total of 656 procedures: 234 laceration repairs, 250 fracture reductions, 85 foreign body removals, 33 abscess incision and drainages, 14 dislocation reductions and 40 other procedures. Telephone follow up was successful in 65% (424) of cases. The mean age was 6.5 years. Family member interference occurred in one case (0.15%, 95% confidence interval 0–0.73%). In 17 cases (2.68%, 95% confidence interval 2.1–5.9%) family members present expressed concerns about the procedure during the telephone follow up but had not interfered at the time of the procedure. There were no significant differences between the concerned parents at follow up and the study group across key patient variables such as child’s age (P = 0.369), weight (P = 0.379), respiratory rate (P = 0.477), sex (P = 0.308), procedure indication (P = 0.308) and airway manoeuvres (P = 0.153).Conclusion:  When family members are encouraged to stay for invasive procedures performed on their child, and careful explanation of the procedure, sedation, possible complications, choice of medication for sedation and possible side‐effects is undertaken, family member interference is extremely rare.
Emerging epidemic in Australia: Abdominal stab wounds. Twenty‐four months at a major trauma centre
Authors: Rozen Warren Matthew , Ma Ellen Hui , Jones Ian T , Judson Rodney Thomas 
Published: May 2007

AbstractBackground:  The incidence of abdominal stab wounds treated at the Royal Melbourne Hospital, Parkville, Vic., Australia has noticeably increased over the 12 month period to March 2006, mirroring an increase in penetrating abdominal trauma throughout many Australian trauma centres. Management protocols for abdominal stab wounds are still contentious. The current study quantifies the increase in stab wounds at the Royal Melbourne Hospital over a 24 month period and analyses the management modalities used.Methods:  A review of the Trauma Unit of the Royal Melbourne Hospital was performed for the period of 20 March 2004 until 20 March 2006. All anterior abdominal stab wounds were collated for the site of injury, investigations performed on admission, results of investigations, operations performed and findings at operation.Results:  There were 4244 emergency trauma presentations over the 24 month period between 20 March 2004 and 20 March 2006. The second 12 month period showed a 21.5% increase in overall trauma admissions and a 91.3% increase in anterior abdominal stabbings. The percentage of stab wounds treated conservatively fell by 21.8%, with the percentage of laparotomies increasing by 14.2%. Almost 30% of all patients undergoing surgery had no visceral injury at operation. Twenty CT scans were performed preoperatively, with a sensitivity of 79% and specificity of 100%.Conclusion:  Abdominal stab wounds treated at Royal Melbourne Hospital have substantially increased over the past 12 months. Although management is still contentious, a management protocol for anterior abdominal stab wounds is proposed, outlining the role of CT scanning, conservative management, laparoscopy and laparotomy.