96 research outputs found
Effect of Grazing Frequency by Dairy Cows on Herb Based Pastures
Herbage production and quality of perennial ryegrass pastures is often limited over the summer months (Powell et al. 2007). Chicory (Cichorium intybus L.) and narrow-leaf plantain (Plantago lanceolata L.) are perennial herbs that accumulate high herbage masses during late spring and summer (Powell et al 2007; Li and Kemp 2005). These perennial herbs are being used by farmers to supplement dairy cows over summer. However, there have been many cases of poor plant persistence with current management practices. The aim of this research was to determine the effect of two grazing frequencies (GF; 2 weeks and 4 weeks) on the herbage production and persistence of pure swards of chicory, plantain and a herb-clover mix (chicory, plantain, red and white clover) over a single growing season
Plasmodium NEK1 coordinates MTOC organisation and kinetochore attachment during rapid mitosis in male gamete formation
Mitosis is an important process in the cell cycle required for cells to divide. Never in mitosis (NIMA)-like kinases (NEKs) are regulators of mitotic functions in diverse organisms. Plasmodium spp., the causative agent of malaria is a divergent unicellular haploid eukaryote with some unusual features in terms of its mitotic and nuclear division cycle that presumably facilitate proliferation in varied environments. For example, during the sexual stage of male gametogenesis that occurs within the mosquito host, an atypical rapid closed endomitosis is observed. Three rounds of genome replication from 1N to 8N and successive cycles of multiple spindle formation and chromosome segregation occur within 8 min followed by karyokinesis to generate haploid gametes. Our previous Plasmodium berghei kinome screen identified 4 Nek genes, of which 2, NEK2 and NEK4, are required for meiosis. NEK1 is likely to be essential for mitosis in asexual blood stage schizogony in the vertebrate host, but its function during male gametogenesis is unknown. Here, we study NEK1 location and function, using live cell imaging, ultrastructure expansion microscopy (U-ExM), and electron microscopy, together with conditional gene knockdown and proteomic approaches. We report spatiotemporal NEK1 location in real-time, coordinated with microtubule organising centre (MTOC) dynamics during the unusual mitoses at various stages of the Plasmodium spp. life cycle. Knockdown studies reveal NEK1 to be an essential component of the MTOC in male cell differentiation, associated with rapid mitosis, spindle formation, and kinetochore attachment. These data suggest that P. berghei NEK1 kinase is an important component of MTOC organisation and essential regulator of chromosome segregation during male gamete formation
A randomized controlled trial of sucrose and/or pacifier as analgesia for infants receiving venipuncture in a pediatric emergency department
<p>Abstract</p> <p>Background</p> <p>Although sucrose has been accepted as an effective analgesic agent for procedural pain in neonates, previous studies are largely in the NICU population using the procedure of heel lance. This is the first report of the effect of sucrose, pacifier or the combination thereof for the procedural pain of venipuncture in infants in the pediatric emergency department population.</p> <p>Methods</p> <p>The study design was a double (sucrose) and single blind (pacifier), placebo-controlled randomized trial – factorial design carried out in a pediatric emergency department. The study population was infants, aged 0 – 6 months. Eighty-four patients were randomly assigned to one of four groups: a) sucrose b) sucrose & pacifier c) control d) control & pacifier. Each child received 2 ml of either 44% sucrose or sterile water, by mouth. The primary outcome measure: FLACC pain scale score change from baseline. Secondary outcome measures: crying time and heart rate change from baseline.</p> <p>Results</p> <p>Sucrose did not significantly reduce the FLACC score, crying time or heart rate. However sub-group analysis revealed that sucrose had a much greater effect in the younger groups. Pacifier use reduced FLACC score (not statistically significant), crying times (statistically significant) but not heart rate. Subgroup analysis revealed a mean crying time difference of 76.52 seconds (p < 0.0171) (0–1 month) and 123.9 seconds (p < 0.0029) (1–3 month). For subgroup age > 3 months pacifier did not have any significant effect on crying time. Age adjusted regression analysis revealed that both sucrose and pacifier had significant effects on crying time. Crying time increased with both increasing age and increasing gestational age.</p> <p>Conclusion</p> <p>Pacifiers are inexpensive, effective analgesics and are easy to use in the PED for venipuncture in infants aged 0–3 months. The benefits of sucrose alone as an analgesic require further investigation in the older infant, but sucrose does appear to provide additional benefit when used with a pacifier in this age group.</p> <p>Trial registration</p> <p>Current Controlled Trials ISRCTN15819627</p
The Genome of the Zoonotic Malaria Parasite Plasmodium simium Reveals Adaptions to Host-switching
Oral Session
Expression Analysis of the Theileria parva Subtelomere-Encoded Variable Secreted Protein Gene Family
Background
The intracellular protozoan parasite Theileria parva transforms bovine lymphocytes inducing uncontrolled proliferation. Proteins released from the parasite are assumed to contribute to phenotypic changes of the host cell and parasite persistence. With 85 members, genes encoding subtelomeric variable secreted proteins (SVSPs) form the largest gene family in T. parva. The majority of SVSPs contain predicted signal peptides, suggesting secretion into the host cell cytoplasm.
Methodology/Principal Findings
We analysed SVSP expression in T. parva-transformed cell lines established in vitro by infection of T or B lymphocytes with cloned T. parva parasites. Microarray and quantitative real-time PCR analysis revealed mRNA expression for a wide range of SVSP genes. The pattern of mRNA expression was largely defined by the parasite genotype and not by host background or cell type, and found to be relatively stable in vitro over a period of two months. Interestingly, immunofluorescence analysis carried out on cell lines established from a cloned parasite showed that expression of a single SVSP encoded by TP03_0882 is limited to only a small percentage of parasites. Epitope-tagged TP03_0882 expressed in mammalian cells was found to translocate into the nucleus, a process that could be attributed to two different nuclear localisation signals.
Conclusions
Our analysis reveals a complex pattern of Theileria SVSP mRNA expression, which depends on the parasite genotype. Whereas in cell lines established from a cloned parasite transcripts can be found corresponding to a wide range of SVSP genes, only a minority of parasites appear to express a particular SVSP protein. The fact that a number of SVSPs contain functional nuclear localisation signals suggests that proteins released from the parasite could contribute to phenotypic changes of the host cell. This initial characterisation will facilitate future studies on the regulation of SVSP gene expression and the potential biological role of these enigmatic proteins
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Ten-year assessment of the 100 priority questions for global biodiversity conservation
In 2008, a group of conservation scientists compiled a list of 100 priority questions for the conservation of the world's biodiversity ?Sutherland et al. (2009) Conservation Biology, 23, 557?567?. However, now almost a decade later, no one has yet published a study gauging how much progress has been made in addressing these 100 high?priority questions in the peer?reviewed literature. Here we take a first step toward re?examining the 100 questions and identify key knowledge gaps that still remain. Through a combination of a questionnaire and a literature review, we evaluated each of the 100 questions on the basis of two criteria: relevance and effort. We defined highly?relevant questions as those which ? if answered ? would have the greatest impact on global biodiversity conservation, while effort was quantified based on the number of review publications addressing a particular question, which we used as a proxy for research effort. Using this approach we identified a set of questions that, despite being perceived as highly relevant, have been the focus of relatively few review publications over the past ten years. These questions covered a broad range of topics but predominantly tackled three major themes: the conservation and management of freshwater ecosystems, the role of societal structures in shaping interactions between people and the environment, and the impacts of conservation interventions. We see these questions as important knowledge gaps that have so far received insufficient attention and may need to be prioritised in future research
Young ghosts: ethical and methodological issues of historical research in children's geographies
This paper was published in the journal, Children's Geographies [© Taylor & Francis] and the definitive version is available at: http://dx.doi.org/10.1080/14733285.2012.693838Geographers researching children and young people have often been at the forefront of disciplinary
debates in geography surrounding methodological practice and ethical considerations
(Matthews et al. 1998, Valentine 1999, Pain 2004, Hemming 2008, Hopkins and Bell 2008,
van Blerk and Barker 2008). In this short paper, I want to focus on a less-popular research
method used by children’s geographers – archival methods (cf. Gagen 2000, 2001) – and
reflect specifically on some of its methodological and ethical challenges. I argue that thinking
about historical research can challenge children’s geographers to consider other types of encounter
from that of the (embodied) encounter between a researcher and a child (Horton 2008). These
different and multiple encounters include those between the (adult) creator of ‘material’ and a
young person, a young person (as creator) and their intended audience, and the further encounter
between a young person from the past and a present-day researcher during fieldwork. The spatial
and temporal deferral in some of these encounters suggests a re-thinking of how we approach and
conceptualise research ‘with’ young people. Furthermore, these (dis)embodied encounters can
challenge ethical norms in children’s geographies such as consent, confidentiality and positionality
in different but overlapping ways. I contend that children’s geographers are well versed in
these ethical issues, some of which transfer well into the practice of historical research. For
example, issues surrounding children’s ‘voice’ and responsibility are quite similar (as I later
discuss), but there is a difference between contemporary and historical research in terms of the
media involved (your own tape recordings or someone else’s recorded tapes; fresh participatory
artwork or dust-covered diaries) and a different retrieval process (direct embodied research with
young people or deferred connections in another building, time and place)
Timing of host feeding drives rhythms in parasite replication
Circadian rhythms enable organisms to synchronise the processes underpinning survival and reproduction to anticipate daily changes in the external environment. Recent work shows that daily (circadian) rhythms also enable parasites to maximise fitness in the context of ecological interactions with their hosts. Because parasite rhythms matter for their fitness, understanding how they are regulated could lead to innovative ways to reduce the severity and spread of diseases. Here, we examine how host circadian rhythms influence rhythms in the asexual replication of malaria parasites. Asexual replication is responsible for the severity of malaria and fuels transmission of the disease, yet, how parasite rhythms are driven remains a mystery. We perturbed feeding rhythms of hosts by 12 hours (i.e. diurnal feeding in nocturnal mice) to desynchronise the hosts' peripheral oscillators from the central, light-entrained oscillator in the brain and their rhythmic outputs. We demonstrate that the rhythms of rodent malaria parasites in day-fed hosts become inverted relative to the rhythms of parasites in night-fed hosts. Our results reveal that the hosts' peripheral rhythms (associated with the timing of feeding and metabolism), but not rhythms driven by the central, light-entrained circadian oscillator in the brain, determine the timing (phase) of parasite rhythms. Further investigation reveals that parasite rhythms correlate closely with blood glucose rhythms. In addition, we show that parasite rhythms resynchronise to the altered host feeding rhythms when food availability is shifted, which is not mediated through rhythms in the host immune system. Our observations suggest that parasites actively control their developmental rhythms. Finally, counter to expectation, the severity of disease symptoms expressed by hosts was not affected by desynchronisation of their central and peripheral rhythms. Our study at the intersection of disease ecology and chronobiology opens up a new arena for studying host-parasite-vector coevolution and has broad implications for applied bioscience
Impacts of cultural dynamics on conservation of Suakin, Sudan
This article was published in the journal Proceedings of the ICE- Engineering Sustainability [http://www.icevirtuallibrary.com/content/serial/ensu]. Permission is granted by ICE Publishing to print one copy for personal use. Any other use of these PDF files is subject to reprint fees.The aim of this work was to explore the impact of local cultural dynamics on the conservation of the built heritage of Suakin, an abandoned historic port on the Red Sea coast of Sudan, through a collaborative stakeholder approach. Key representatives of local stakeholder groups attended a two-day workshop and took part in a series of collaborative activities. These encompassed the production of a rank-ordered list of the key local cultural dynamics impacting on the port's conservation, agreement to a number of actions to address obstacles to conservation, identification of local cultural values collectively determined by stakeholder and confirmation of the value of an integrated conservation approach. The workshop enabled a shared understanding and responsibility between stakeholders and established a commitment to further action to address the key local cultural dynamics impacting on the conservation. This collaborative stakeholder participation represented a new step in the port's conservation and invited the development of more formal protocols to enable the equal representation and participation of stakeholders in future conservation activities and initiatives
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