456 research outputs found

    Body Temperature In Captive Long-Beaked Echidnas (Zaglossus Bartoni)

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    The routine occurrence of both short-term (daily) and long-term torpor (hibernation) in short-beaked echidnas, but not platypus, raises questions about the third monotreme genus, New Guinea's Zaglossus. We measured body temperatures (Tb) with implanted data loggers over three and a half years in two captive Zaglossus bartoni at Taronga Zoo, Sydney. The modal Tb of both long-beaks was 31 degrees C, similar to non-hibernating short-beaked echidnas, Tachyglossus aculeatus, in the wild (30-32 degrees C) and to platypus (32 degrees C), suggesting that this is characteristic of normothermic monotremes. Tb cycled daily, usually over 2-4 degrees C. There were some departures from this pattern to suggest periods of inactivity but nothing to indicate the occurrence of long-term torpor. In contrast, two short-beaked echidnas monitored concurrently in the same pen showed extended periods of low Tb in the cooler months (hibernation) and short periods of torpor at any time of the year, as they do in the wild. Whether torpor or hibernation occurs in Zaglossus in the wild or in juveniles remains unknown. However, given that the environment in this study was conducive to hibernation in short-beaks, which do not easily enter torpor in captivity, and their large size, we think that torpor in wild adult Zaglossus is unlikely

    Body Temperature and Diurnal Activity Patterns In the Platypus (Ornithorhynchus anatinus) During Winter

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    Using implanted radiotransmitters, we monitored body temperatures in five platypuses ranging freely in the Thredbo River in Australia's southern alps between April and October 1988, where the water gets as cold as any that a platypus is likely to encounter. Activity pattern showed a distinct daily cycle. No evidence of hibernation or even brief periods of torpor was found, all individuals maintaining body temperatures close to 32 degrees C throughout the winter (mean s.d., 32.08 0.75 degrees C, range 29.2 34.6 degrees C, n = 2237). No differences were found between the means or the variances of body temperatures of animals during day-time rest in stream-bank burrows and those during night-time foraging in winter at temperatures as low as 1.0 degrees C

    Movements and burrow use by platypuses, Ornithorhynchus anatinus, in the Thredbo River, New South Wales

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    During studies of temperature regulation in 1981 and 1988/89, 11 males and 16 female platypuses were captured in the lower Thredbo River, with 30% of these being recaptured. Eight animals were followed for several days using radiotelemetry, with five being monitored remotely over 2 to 5 months. Although short-term radiotracking showed that most animals foraged wthin I km of where they were caught, one individual moved 1. 3 km in 36 hours and four others ranged over 1. 3 - 2.3 km during the study. Males appeared to be more mobile than females. Implications of these results for mark and recapture studies are discussed. Individuals occupied a number of burrows during the study. One burrow complex was occupied simultaneously by two adult males and, at a different time, by two adult females. Animals rested in burrows for between 5.25 and 15.1 hours at a time and most emerged between the hours of 1815 and 2100

    Novel reporter systems for facile evaluation of I-SceI-mediated genome editing

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    Two major limitations to achieve efficient homing endonuclease-stimulated gene correction using retroviral vectors are low frequency of gene targeting and random integration of the targeting vectors. To overcome these issues, we developed a reporter system for quick and facile testing of novel strategies to promote the selection of cells that undergo targeted gene repair and to minimize the persistence of random integrations and non-homologous end-joining events. In this system, the gene target has an I-SceI site upstream of an EGFP reporter; and the repair template includes a non-functional EGFP gene, the positive selection transgene MGMTP140K tagged with mCherry, and the inducible Caspase-9 suicide gene. Using this dual fluorescent reporter system it is possible to detect properly targeted integration. Furthermore, this reporter system provides an efficient approach to enrich for gene correction events and to deplete events produced by random integration. We have also developed a second reporter system containing MGMTP140K in the integrated target locus, which allows for selection of primary cells with the integrated gene target after transplantation. This system is particularly useful for testing repair strategies in primary hematopoietic stem cells. Thus, our reporter systems should allow for more efficient gene correction with less unwanted off target effects

    A systematic review of the use of an expertise-based randomised controlled trial design

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    Acknowledgements JAC held a Medical Research Council UK methodology (G1002292) fellowship, which supported this research. The Health Services Research Unit, Institute of Applied Health Sciences (University of Aberdeen), is core-funded by the Chief Scientist Office of the Scottish Government Health and Social Care Directorates. Views express are those of the authors and do not necessarily reflect the views of the funders.Peer reviewedPublisher PD

    Malaria early warning tool: linking inter-annual climate and malaria variability in northern Guadalcanal, Solomon Islands

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    BACKGROUND: Malaria control remains a significant challenge in the Solomon Islands. Despite progress made by local malaria control agencies over the past decade, case rates remain high in some areas of the country. Studies from around the world have confirmed important links between climate and malaria transmission. This study focuses on understanding the links between malaria and climate in Guadalcanal, Solomon Islands, with a view towards developing a climate-based monitoring and early warning for periods of enhanced malaria transmission. METHODS: Climate records were sourced from the Solomon Islands meteorological service (SIMS) and historical malaria case records were sourced from the National Vector-Borne Disease Control Programme (NVBDCP). A declining trend in malaria cases over the last decade associated with improved malaria control was adjusted for. A stepwise regression was performed between climate variables and climate-associated malaria transmission (CMT) at different lag intervals to determine where significant relationships existed. The suitability of these results for use in a three-tiered categorical warning system was then assessed using a Mann-Whitney U test. RESULTS: Of the climate variables considered, only rainfall had a consistently significant relationship with malaria in North Guadalcanal. Optimal lag intervals were determined for prediction using R2 skill scores. A highly significant negative correlation (R = - 0.86, R2 = 0.74, p < 0.05, n = 14) was found between October and December rainfall at Honiara and CMT in northern Guadalcanal for the subsequent January-June. This indicates that drier October-December periods are followed by higher malaria transmission periods in January-June. Cross-validation emphasized the suitability of this relationship for forecasting purposes [Formula: see text]  as did Mann-Whitney U test results showing that rainfall below or above specific thresholds was significantly associated with above or below normal malaria transmission, respectively. CONCLUSION: This study demonstrated that rainfall provides the best predictor of malaria transmission in North Guadalcanal. This relationship is thought to be underpinned by the unique hydrological conditions in northern Guadalcanal which allow sandbars to form across the mouths of estuaries which act to develop or increase stagnant brackish marshes in low rainfall periods. These are ideal habitats for the main mosquito vector, Anopheles farauti. High rainfall accumulations result in the flushing of these habitats, reducing their viability. The results of this study are now being used as the basis of a malaria early warning system which has been jointly implemented by the SIMS, NVBDCP and the Australian Bureau of Meteorology

    The Wolbachia Genome of Brugia malayi: Endosymbiont Evolution within a Human Pathogenic Nematode

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    Complete genome DNA sequence and analysis is presented for Wolbachia, the obligate alpha-proteobacterial endosymbiont required for fertility and survival of the human filarial parasitic nematode Brugia malayi. Although, quantitatively, the genome is even more degraded than those of closely related Rickettsia species, Wolbachia has retained more intact metabolic pathways. The ability to provide riboflavin, flavin adenine dinucleotide, heme, and nucleotides is likely to be Wolbachia's principal contribution to the mutualistic relationship, whereas the host nematode likely supplies amino acids required for Wolbachia growth. Genome comparison of the Wolbachia endosymbiont of B. malayi (wBm) with the Wolbachia endosymbiont of Drosophila melanogaster (wMel) shows that they share similar metabolic trends, although their genomes show a high degree of genome shuffling. In contrast to wMel, wBm contains no prophage and has a reduced level of repeated DNA. Both Wolbachia have lost a considerable number of membrane biogenesis genes that apparently make them unable to synthesize lipid A, the usual component of proteobacterial membranes. However, differences in their peptidoglycan structures may reflect the mutualistic lifestyle of wBm in contrast to the parasitic lifestyle of wMel. The smaller genome size of wBm, relative to wMel, may reflect the loss of genes required for infecting host cells and avoiding host defense systems. Analysis of this first sequenced endosymbiont genome from a filarial nematode provides insight into endosymbiont evolution and additionally provides new potential targets for elimination of cutaneous and lymphatic human filarial disease
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