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81.
Modelling species distributions without using species distributions: the cane toad in Australia under current and future climates 总被引:4,自引:1,他引:3
Michael Kearney Ben L. Phillips Christopher R. Tracy Keith A. Christian Gregory Betts Warren P. Porter 《Ecography》2008,31(4):423-434
Accurate predictions of the potential distribution of range-shifting species are required for effective management of invasive species, and for assessments of the impact of climate change on native species. Range-shifting species pose a challenge for traditional correlative approaches to range prediction, often requiring the extrapolation of complex statistical associations into novel environmental space. Here we take an alternative approach that does not use species occurrence data, but instead captures the fundamental niche of a species by mechanistically linking key organismal traits with spatial data using biophysical models. We demonstrate this approach with a major invasive species, the cane toad Bufo marinus in Australia, assessing the direct climatic constraints on its ability to move, survive, and reproduce. We show that the current range can be explained by thermal constraints on the locomotor potential of the adult stage together with limitations on the availability of water for the larval stage. Our analysis provides a framework for biologically grounded predictions of the potential for cane toads to expand their range under current and future climate scenarios. More generally, by quantifying spatial variation in physiological constraints on an organism, trait-based approaches can be used to investigate the range-limits of any species. Assessments of spatial variation in the physiological constraints on an organism may also provide a mechanistic basis for forecasting the rate of range expansion and for understanding a species' potential to evolve at range-edges. Mechanistic approaches thus have broad application to process-based ecological and evolutionary models of range-shift. 相似文献
82.
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Emily HM Wong David K Smith Raul Rabadan Malik Peiris Leo LM Poon 《BMC evolutionary biology》2010,10(1):253
Background
The influenza A virus is an important infectious cause of morbidity and mortality in humans and was responsible for 3 pandemics in the 20th century. As the replication of the influenza virus is based on its host's machinery, codon usage of its viral genes might be subject to host selection pressures, especially after interspecies transmission. A better understanding of viral evolution and host adaptive responses might help control this disease. 相似文献84.
Decellularised tissue allografts have been used in reconstructive surgical applications and transplantation for many years. Some of the current methods of sterilisation have a detrimental effect on the tissue graft structure and function. The anti-microbial activity of cupric ions and hydrogen peroxide (H2O2) are well known however their combined application is not currently utilised as a decontamination agent in the tissue banking world sector. The aim of this study was to determine the combined concentrations of copper chloride (CuCl2) and H2O2 that have the optimal bactericidal and sporicidal activity on decellularised (dCELL) human dermis. The first part of this study established the decimal reduction time (D-value) of CuCl2 (0.1 mg/L and 1 mg/L) together with H2O2 (0.01, 0.1, 0.5 and 1%) for Staphylococcus epidermidis, Escherichia coli and Bacillus subtilis spores. The second part of this study identified the most effective CuCl2 and H2O2 concentration that decontaminated dCELL human dermis inoculated with these pathogens. Of all the concentrations tested, 0.1 mg/L CuCl2 in combination with 1% H2O2 had the shortest D-value; S. epidermidis D = 3.15 min, E. coli D = 2.62 min and B. subtilis spores D = 18.05 min. However when adsorbed onto dCELL dermis, S. epidermidis and E. coli were more susceptible to 1 mg/L CuCl2 together with 0.5% H2O2. These studies show promise of CuCl2–H2O2 formulations as potential sterilants for decellularised dermal allografts. 相似文献
85.
Datsen George Wei Vicki Chiang Elizabeth Fyne Mini Balakrishnan Tiffany Barnes Michael Graupe Joseph Hesselgesser Alivelu Irrinki Jeffrey P. Murry George Stepan Kirsten M. Stray Angela Tsai Helen Yu Jonathan Spindler Mary Kearney Celsa A. Spina Deborah McMahon Jacob Lalezari Derek Sloan John Mellors Romas Geleziunas Tomas Cihlar 《PLoS pathogens》2014,10(4)
Persistent latent reservoir of replication-competent proviruses in memory CD4 T cells is a major obstacle to curing HIV infection. Pharmacological activation of HIV expression in latently infected cells is being explored as one of the strategies to deplete the latent HIV reservoir. In this study, we characterized the ability of romidepsin (RMD), a histone deacetylase inhibitor approved for the treatment of T-cell lymphomas, to activate the expression of latent HIV. In an in vitro T-cell model of HIV latency, RMD was the most potent inducer of HIV (EC50 = 4.5 nM) compared with vorinostat (VOR; EC50 = 3,950 nM) and other histone deacetylase (HDAC) inhibitors in clinical development including panobinostat (PNB; EC50 = 10 nM). The HIV induction potencies of RMD, VOR, and PNB paralleled their inhibitory activities against multiple human HDAC isoenzymes. In both resting and memory CD4 T cells isolated from HIV-infected patients on suppressive combination antiretroviral therapy (cART), a 4-hour exposure to 40 nM RMD induced a mean 6-fold increase in intracellular HIV RNA levels, whereas a 24-hour treatment with 1 µM VOR resulted in 2- to 3-fold increases. RMD-induced intracellular HIV RNA expression persisted for 48 hours and correlated with sustained inhibition of cell-associated HDAC activity. By comparison, the induction of HIV RNA by VOR and PNB was transient and diminished after 24 hours. RMD also increased levels of extracellular HIV RNA and virions from both memory and resting CD4 T-cell cultures. The activation of HIV expression was observed at RMD concentrations below the drug plasma levels achieved by doses used in patients treated for T-cell lymphomas. In conclusion, RMD induces HIV expression ex vivo at concentrations that can be achieved clinically, indicating that the drug may reactivate latent HIV in patients on suppressive cART. 相似文献
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Epilepsy is a common neurological disorder affecting approximately 1% of the population. Mutations in voltage‐gated sodium channels are responsible for several monogenic epilepsy syndromes. More than 800 mutations in the voltage‐gated sodium channel SCN1A have been reported in patients with generalized epilepsy with febrile seizures plus and Dravet syndrome. Heterozygous loss‐of‐function mutations in SCN1A result in Dravet syndrome, a severe infant‐onset epileptic encephalopathy characterized by intractable seizures, developmental delays and increased mortality. A common feature of monogenic epilepsies is variable expressivity among individuals with the same mutation, suggesting that genetic modifiers may influence clinical severity. Mice with heterozygous deletion of Scn1a (Scn1a+/?) model a number of Dravet syndrome features, including spontaneous seizures and premature lethality. Phenotype severity in Scn1a+/? mice is strongly dependent on strain background. On the 129S6/SvEvTac strain Scn1a+/? mice exhibit no overt phenotype, whereas on the (C57BL/6J × 129S6/SvEvTac)F1 strain Scn1a+/? mice exhibit spontaneous seizures and early lethality. To systematically identify loci that influence premature lethality in Scn1a+/? mice, we performed genome scans on reciprocal backcrosses. Quantitative trait locus mapping revealed modifier loci on mouse chromosomes 5, 7, 8 and 11. RNA‐seq analysis of strain‐dependent gene expression, regulation and coding sequence variation provided a list of potential functional candidate genes at each locus. Identification of modifier genes that influence survival in Scn1a+/? mice will improve our understanding of the pathophysiology of Dravet syndrome and may suggest novel therapeutic strategies for improved treatment of human patients. 相似文献
88.
89.
Hanna W van Steenbergen Jessica AB van Nies Tom WJ Huizinga Monique Reijnierse Annette HM van der Helm-van Mil 《Arthritis research & therapy》2014,16(2):R92
Introduction
It is known that anticitrullinated peptide antibody (ACPA)–positive rheumatoid arthritis (RA) has a preclinical phase. Whether this phase is also present in ACPA-negative RA is unknown. To determine this, we studied ACPA-negative arthralgia patients who were considered prone to progress to RA for local subclinical inflammation observed on hand and foot magnetic resonance imaging (MRI) scans.Methods
We studied a total of 64 ACPA-negative patients without clinically detectable arthritis and with arthralgia of the small joints within the previous 1 year. Because of the character of the patients’ symptoms, the rheumatologists considered these patients to be prone to progress to RA. For comparisons, we evaluated 19 healthy, symptom-free controls and 20 ACPA-negative RA patients, who were identified according to the 1987 American Rheumatism Association criteria. All participants underwent MRI of unilateral wrist, metacarpophalangeal and metatarsophalangeal joints. Synovitis and bone marrow oedema (BME) were scored according to the OMERACT rheumatoid arthritis magnetic resonance imaging scoring system, and the scores were summed to yield the ‘MRI inflammation score’. Scores were compared between groups. Among the ACPA-negative arthralgia patients, MRI inflammation scores were related to C-reactive protein (CRP) levels and the tenderness of scanned joints.Results
MRI inflammation scores increased progressively among the groups of controls and ACPA-negative arthralgia and RA patients (median scores = 0, 1 and 10, respectively; P < 0.001). The MRI inflammation scores of ACPA-negative arthralgia patients were significantly higher than those of controls (P = 0.018). In particular, the synovitis scores were higher in ACPA-negative arthralgia patients (P = 0.046). Among the ACPA-negative arthralgia patients, inflammation was observed predominantly in the wrist (53%). The synovitis scores were associated with CRP levels (P = 0.007) and joint tenderness (P = 0.026). Despite the limited follow-up duration, five patients developed clinically detectable arthritis. These five patients had higher scores for MRI inflammation (P = 0.001), synovitis (P = 0.002) and BME (P = 0.003) compared to the other patients.Conclusion
Subclinical synovitis was observed in the small joints of ACPA-negative arthralgia patients, and especially in patients whose conditions progressed to clinically detectable arthritis. This finding suggests the presence of a preclinical phase in ACPA-negative RA. Further longitudinal studies of these lesions and patients are required to confirm this hypothesis. 相似文献90.
Rachel Knevel Diederik PC de Rooy Tore Saxne Elisabet Lindqvist Martha K Leijsma Nina A Daha Bobby PC Koeleman Roula Tsonaka Jeanine J Houwing-Duistermaat Joris JM Schonkeren Rene EM Toes Tom WJ Huizinga Elisabeth Brouwer Anthony G Wilson Annette HM van der Helm-van Mil 《Arthritis research & therapy》2014,16(3):R108