1,257 research outputs found

    Bacterial Communities of Two Ubiquitous Great Barrier Reef Corals Reveals Both Site- and Species-Specificity of Common Bacterial Associates

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    Background: Coral-associated bacteria are increasingly considered to be important in coral health, and altered bacterial community structures have been linked to both coral disease and bleaching. Despite this, assessments of bacterial communities on corals rarely apply sufficient replication to adequately describe the natural variability. Replicated data such as these are crucial in determining potential roles of bacteria on coral

    The Ecology of ‘Acroporid White Syndrome', a Coral Disease from the Southern Great Barrier Reef

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    Outbreaks of coral disease have increased worldwide over the last few decades. Despite this, remarkably little is known about the ecology of disease in the Indo-Pacific Region. Here we report the spatiotemporal dynamics of a coral disease termed ‘Acroporid white syndrome’ observed to affect tabular corals of the genus Acropora on the southern Great Barrier Reef. The syndrome is characterised by rapid tissue loss initiating in the basal margins of colonies, and manifests as a distinct lesion boundary between apparently healthy tissue and exposed white skeleton. Surveys of eight sites around Heron Reef in 2004 revealed a mean prevalence of 8.1±0.9%, affecting the three common species (Acropora cytherea, A. hyacinthus, A. clathrata) and nine other tabular Acropora spp. While all sizes of colonies were affected, white syndrome disproportionately affected larger colonies of tabular Acroporids (>80 cm). The prevalence of white syndrome was strongly related to the abundance of tabular Acroporids within transects, yet the incidence of the syndrome appears unaffected by proximity to other colonies, suggesting that while white syndrome is density dependant, it does not exhibit a strongly aggregated spatial pattern consistent with previous coral disease outbreaks. Acroporid white syndrome was not transmitted by either direct contact in the field or by mucus in aquaria experiments. Monitoring of affected colonies revealed highly variable rates of tissue loss ranging from 0 to 1146 cm−2 week−1, amongst the highest documented for a coral disease. Contrary to previous links between temperature and coral disease, rates of tissue loss in affected colonies increased threefold during the winter months. Given the lack of spatial pattern and non-infectious nature of Acroporid white syndrome, further studies are needed to determine causal factors and longer-term implications of disease outbreaks on the Great Barrier Reef

    One Year of Alendronate Treatment Lowers Microstructural Stresses Associated with Trabecular Microdamage Initiation

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    Alendronate, an anti-remodeling agent, is commonly used to treat patients suffering from osteoporosis by increasing bone mineral density. Though fracture risk is lowered, an increase in microdamage accumulation has been documented in patients receiving alendronate, leading to questions about the potentially detrimental effects of remodeling suppression on the local tissue (material) properties. In this study, trabecular bone cores from the distal femur of beagle dogs treated for one year with alendronate, at doses scaled by weight to approximate osteoporotic and Paget's disease treatment doses in humans, were subjected to uniaxial compression to induce microdamage. Tissue level von Mises stresses were computed for alendronate-treated and non-treated controls using finite element analysis and correlated to microdamage morphology. Using a modified version of the Moore and Gibson classification for damage morphology, we determined that the von Mises stress for trabeculae exhibiting severe and linear microcrack patterns was decreased by approximately 25% in samples treated with alendronate compared with non-treated controls (p<0.01), whereas there was no reduction in the von Mises stress state for diffuse microdamage formation. Furthermore, an examination of the architectural and structural characteristics of damaged trabeculae demonstrated that severely damaged trabeculae were thinner, more aligned with the loading axis, and less mineralized than undamaged trabeculae in alendronate-treated samples (p<0.01). Similar relationships with damage morphology were found only with trabecular orientation in vehicle-treated control dogs. These results indicate that changes in bone's architecture and matrix properties associated with one year of alendronate administration reduce trabecular bone's ability to resist the formation of loading-induced severe and linear microcracks, both of which dissipate less energy prior to fracture than does diffuse damage

    The Nondeterministic Waiting Time Algorithm: A Review

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    We present briefly the Nondeterministic Waiting Time algorithm. Our technique for the simulation of biochemical reaction networks has the ability to mimic the Gillespie Algorithm for some networks and solutions to ordinary differential equations for other networks, depending on the rules of the system, the kinetic rates and numbers of molecules. We provide a full description of the algorithm as well as specifics on its implementation. Some results for two well-known models are reported. We have used the algorithm to explore Fas-mediated apoptosis models in cancerous and HIV-1 infected T cells

    Tolerance of endolithic algae to elevated temperature and light in the coral Montipora monasteriata from the southern Great Barrier Reef

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    Photosynthetic endolithic algae and cyanobacteria live within the skeletons of many scleractinians. Under normal conditions, less than 5% of the photosynthetically active radiation (PAR) reaches the green endolithic algae because of the absorbance of light by the endosymbiotic dinoflagellates and the carbonate skeleton. When corals bleach (loose dinoflagellate symbionts), however, the tissue of the corals become highly transparent and photosynthetic microendoliths may be exposed to high levels of both thermal and solar stress. This study explores the consequence of these combined stresses on the phototrophic endoliths inhabiting the skeleton of Montipora monasteriata, growing at Heron Island, on the southern Great Barrier Reef. Endoliths that were exposed to sun after tissue removal were by far more susceptible to thermal photoinhibition and photo-damage than endoliths under coral tissue that contained high concentrations of brown dinoflagellate symbionts. While temperature or light alone did not result in decreased photosynthetic efficiency of the endoliths, combined thermal and solar stress caused a major decrease and delayed recovery. Endoliths protected under intact tissue recovered rapidly and photoacclimated soon after exposure to elevated sea temperatures. Endoliths under naturally occurring bleached tissue of M. monasteriata colonies (bleaching event in March 2004 at Heron Island) acclimated to increased irradiance as the brown symbionts disappeared. We suggest that two major factors determine the outcome of thermal bleaching to the endolith community. The first is the microhabitat and light levels under which a coral grows, and the second is the susceptibility of the coral-dinoflagellates symbiosis to thermal stress. More resistant corals may take longer to bleach allowing endoliths time to acclimate to a new light environment. This in turn may have implications for coral survival

    Lie families: theory and applications

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    We analyze families of non-autonomous systems of first-order ordinary differential equations admitting a common time-dependent superposition rule, i.e., a time-dependent map expressing any solution of each of these systems in terms of a generic set of particular solutions of the system and some constants. We next study relations of these families, called Lie families, with the theory of Lie and quasi-Lie systems and apply our theory to provide common time-dependent superposition rules for certain Lie families.Comment: 23 pages, revised version to appear in J. Phys. A: Math. Theo

    The dynamic mass spectrometry probe (DMSP) - Advanced process analytics for therapeutic cell manufacturing, health monitoring and biomarker discovery

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    Spatially and temporally resolved in situ monitoring of biochemical cell culture environments, e.g., in application to therapeutic cell bioreactors, is of critical importance for facilitating the development of new and reliable quality control methodologies for cell therapies. Identifying and monitoring secreted biomolecular critical quality attributes (CQAs) to enable online feedback control will enable large scale, cost-effective manufacturing of therapeutic cells. These CQA biomarkers have varying concentrations within a bioreactor, both in time and space. Current methods for monitoring these diverse biomolecules are generally ex-situ, time consuming, destructive, provide bulk measurements, or lack the ability to reveal the complete secretome/metabolome composition. The Dynamic Mass Spectrometry Probe (DMSP) synergistically incorporates a sampling interface for localized intake of a small fluid volume of the cellular content, a micro-fabricated mass exchanger for sample conditioning and inline separation, and an integrated electrospray ionization (ESI) emitter for softly ionizing (i.e. preserved biochemical structure) extracted biomolecules for mass spectrometry (MS). ESI-MS via DMSP treatment enables both biomarker discovery and transient (~1 min) analysis of biochemical information indicative of cell health and potency. DMSP is manufactured using advanced batch microfabrication techniques, which minimize dead volume (~20 nL) and ensure repeatable operation and precise geometry of each device. DMSP treatment removes 99% of compounds that interfere with mass spectrometry analysis, such as inorganic salts, while retaining biomolecules of interest within the sample for ESI-MS analysis. DMSP has demonstrated the ability to substantially increase signal to noise ratio in MS detection of biomolecules, and to further enhance sensitivity for probing lower biomarker concentrations via introduction of ESI-MS enhancing molecules (i.e. proton donating chemicals, protein denaturing solvents, and supercharging agents) into the sample within the integrated mass exchanger. To exemplify the DMSP’s unique capabilities, Fig. 1 demonstrates detection of multiple low-concentration protein biomarkers sampled from a biochemically-complex cell media solution serving as a proxy to samples taken directly from cell growth bioreactors [1]. Please click Additional Files below to see the full abstract

    Superposition rules for higher-order systems and their applications

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    Superposition rules form a class of functions that describe general solutions of systems of first-order ordinary differential equations in terms of generic families of particular solutions and certain constants. In this work we extend this notion and other related ones to systems of higher-order differential equations and analyse their properties. Several results concerning the existence of various types of superposition rules for higher-order systems are proved and illustrated with examples extracted from the physics and mathematics literature. In particular, two new superposition rules for second- and third-order Kummer--Schwarz equations are derived.Comment: (v2) 33 pages, some typos corrected, added some references and minor commentarie

    The impact of ocean acidification on the functional morphology of foraminifera

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    This work was supported by the NERC UK Ocean Acidification Research Programme grant NE/H017445/1. WENA acknowledges NERC support (NE/G018502/1). DMP received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.Culturing experiments were performed on sediment samples from the Ythan Estuary, N. E. Scotland, to assess the impacts of ocean acidification on test surface ornamentation in the benthic foraminifer Haynesina germanica. Specimens were cultured for 36 weeks at either 380, 750 or 1000 ppm atmospheric CO2. Analysis of the test surface using SEM imaging reveals sensitivity of functionally important ornamentation associated with feeding to changing seawater CO2 levels. Specimens incubated at high CO2 levels displayed evidence of shell dissolution, a significant reduction and deformation of ornamentation. It is clear that these calcifying organisms are likely to be vulnerable to ocean acidification. A reduction in functionally important ornamentation could lead to a reduction in feeding efficiency with consequent impacts on this organism’s survival and fitness.Publisher PDFPeer reviewe

    Integrated approach to designing growth factor delivery systems

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154661/1/fsb2fj067873com-sup-0001.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154661/2/fsb2fj067873com.pd
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